Next Issue
Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Water, Volume 10, Issue 2 (February 2018)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story (view full-size image) Waste stabilisation pond (WSP) performance is significantly affected by poor hydraulic control. [...] Read more.
View options order results:
result details:
Displaying articles 1-145
Export citation of selected articles as:

Research

Jump to: Review, Other

Open AccessArticle Land Cover Change Detection in Urban Lake Areas Using Multi-Temporary Very High Spatial Resolution Aerial Images
Water 2018, 10(2), 1; doi:10.3390/w10020001
Received: 11 December 2017 / Revised: 10 January 2018 / Accepted: 18 January 2018 / Published: 23 January 2018
PDF Full-text (5852 KB) | HTML Full-text | XML Full-text
Abstract
The availability of very high spatial resolution (VHR) remote sensing imagery provides unique opportunities to exploit meaningful change information in detail with object-oriented image analysis. This study investigated land cover (LC) changes in Shahu Lake of Wuhan using multi-temporal VHR aerial images in
[...] Read more.
The availability of very high spatial resolution (VHR) remote sensing imagery provides unique opportunities to exploit meaningful change information in detail with object-oriented image analysis. This study investigated land cover (LC) changes in Shahu Lake of Wuhan using multi-temporal VHR aerial images in the years 1978, 1981, 1989, 1995, 2003, and 2011. A multi-resolution segmentation algorithm and CART (classification and regression trees) classifier were employed to perform highly accurate LC classification of the individual images, while a post-classification comparison method was used to detect changes. The experiments demonstrated that significant changes in LC occurred along with the rapid urbanization during 1978–2011. The dominant changes that took place in the study area were lake and vegetation shrinking, replaced by high density buildings and roads. The total area of Shahu Lake decreased from ~7.64 km2 to ~3.60 km2 during the past 33 years, where 52.91% of its original area was lost. The presented results also indicated that urban expansion and inadequate legislative protection are the main factors in Shahu Lake’s shrinking. The object-oriented change detection schema presented in this manuscript enables us to better understand the specific spatial changes of Shahu Lake, which can be used to make reasonable decisions for lake protection and urban development. Full article
(This article belongs to the Special Issue Optimizing Land Use Patterns in a Context of Watershed Management)
Figures

Figure 1

Open AccessArticle Near-Bed Monitoring of Suspended Sediment during a Major Flood Event Highlights Deficiencies in Existing Event-Loading Estimates
Water 2018, 10(2), 34; doi:10.3390/w10020034
Received: 15 November 2017 / Revised: 16 December 2017 / Accepted: 17 January 2018 / Published: 23 January 2018
PDF Full-text (7075 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Rates of fluvial sediment discharge are notoriously difficult to quantify, particularly during major flood events. Measurements are typically undertaken using event stations requiring large capital investment, and the high cost tends to reduce the spatial coverage of monitoring sites. This study aimed to
[...] Read more.
Rates of fluvial sediment discharge are notoriously difficult to quantify, particularly during major flood events. Measurements are typically undertaken using event stations requiring large capital investment, and the high cost tends to reduce the spatial coverage of monitoring sites. This study aimed to characterise the near-bed suspended sediment dynamics during a major flood event using a low-cost approach. Monitoring nodes consisted of a total suspended sediment (TSS) logger, a single stage sampler, and a time-lapse camera for a total cost of less than US$420. Seven nodes were deployed across an elevation gradient on the stream bank of Laidley Creek, Queensland, Australia, and two of these nodes successfully characterised the near-bed suspended sediment dynamics across a major flood event. Near-bed TSS concentrations were closely related to stream flow, with the contribution of suspended bed material dominating the total suspended load during peak flows. Observed TSS concentrations were orders of magnitude higher than historical monitoring data for this site collected using the State government event station. This difference was attributed to the event station pump inlet screening the suspended bed material prior to sample collection. The ‘first flush’ phenomenon was detected and attributed to a local resuspension of muddy crusts immediately upstream of the study site. This low-cost approach will provide an important addition to the existing monitoring of fluvial sediment discharge during flood events. Full article
Figures

Figure 1

Open AccessArticle Assessment of Water Quality in Roof-Harvested Rainwater Barrels in Greater Philadelphia
Water 2018, 10(2), 92; doi:10.3390/w10020092
Received: 9 November 2017 / Revised: 14 January 2018 / Accepted: 15 January 2018 / Published: 24 January 2018
PDF Full-text (1330 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A study of water quality parameters was conducted in 38 small-scale roof-harvested rainwater barrels (RHRB) located in urban and peri-urban Philadelphia, USA in winter (November–December) 2014 and summer (June–August 2016). Parameters included two fecal indicator bacteria (FIB) (Escherichia coli and Enterococcus spp.)
[...] Read more.
A study of water quality parameters was conducted in 38 small-scale roof-harvested rainwater barrels (RHRB) located in urban and peri-urban Philadelphia, USA in winter (November–December) 2014 and summer (June–August 2016). Parameters included two fecal indicator bacteria (FIB) (Escherichia coli and Enterococcus spp.) measured using culture-based methods, eight potential enteric and opportunistic pathogens (Campylobacter jejuni, Acanthamoeba spp., Legionella spp., L. pneumophila, Naegleria fowleri, Pseudomonas aeruginosa, Mycobacterium avium and Mycobacterium intracellulare) measured using quantitative polymerase chain reaction (qPCR), and two metals (lead and zinc) using inductively coupled plasma mass spectrometry (ICP-MS). Fecal indicator bacteria were detected in greater than 60% RHRB samples and concentrations (up to >103 per 100 mL) exceeded US Food and Drug Administration (USFDA) irrigation water quality standards. Among the enteric and opportunistic pathogens tested, 57.9, 44.7, 21.1, 18.4, 5 and 3% were PCR positive for Legionella spp., M. intracellulare, M. avium, Acanthamoeba spp., P. aeruginosa, and C. jejuni, respectively. N. fowleri and L. pneumophila were not detected in any sample. The concentrations of enteric and opportunistic pathogens ranged from 102 to 107 gene copies/L of barrel water. Lead and zinc were each observed in 88.5% of RHRB but the concentrations did not exceed US Environmental Protection Agency (USEPA) standards for irrigating produce, with the exception of one zinc observation (2660 µg/L). Based on these data, it appears that the risk associated with metals in RHRB is likely to be low, as these barrels are only used for gardening and non-potable purposes. However, risks due to fecal and opportunistic pathogens may be higher due to exposure to aerosols during gardening activities and produce consumed raw, and should be investigated further. Full article
(This article belongs to the Special Issue Health Risks of Alternative Water Sources)
Figures

Open AccessArticle Long-Term Stability of Low-Pressure Reverse Osmosis (RO) Membrane Operation—A Pilot Scale Study
Water 2018, 10(2), 93; doi:10.3390/w10020093
Received: 13 December 2017 / Revised: 11 January 2018 / Accepted: 18 January 2018 / Published: 23 January 2018
PDF Full-text (9852 KB) | HTML Full-text | XML Full-text
Abstract
Reverse osmosis (RO) elements operating at a low pressure (LP) or a low energy (LE) are generally called “LPRO” or “LERO”, and the nomenclature “LP” and “LE” are convertible due to the interrelated features of the pressure and the energy in the RO
[...] Read more.
Reverse osmosis (RO) elements operating at a low pressure (LP) or a low energy (LE) are generally called “LPRO” or “LERO”, and the nomenclature “LP” and “LE” are convertible due to the interrelated features of the pressure and the energy in the RO process. Not only can LPRO be operated at lower pressures, which enables energy saving, but also at the standard operating pressure with an enhanced permeate flux. In this study, the feasibility of the LPRO element was evaluated in the face of high fouling potential feed water. The commercially available standard RO and LPRO were chosen, and the membrane properties including the fouling susceptibility and the surface characteristics were thoroughly evaluated. The variations of various performance parameters were monitored during an 872 h operation in a pilot system, which was operated in a constant flux mode. Then, the used membranes were analyzed to further verify the fouling load localization and the fouling intensities. The average flux variation of the individual RO elements in a vessel and the economic feasibility of LPRO were also evaluated through a simulation study using an RO system design software. This study showed that the localization of fouling load within a pressure vessel of an LPRO system caused about 20% higher flux decline and almost 2-times higher salt passage than those of a standard RO membrane system. Furthermore, the simulation study predicted that average operating pressure difference ratio (%) between two RO membranes decreased from 24.4% to 17.8% and a substantial quantity of LPRO elements (83.3%) must be replaced to meet the designated water criteria only after 2 years’ operation. Full article
(This article belongs to the Special Issue Sustainable Water Supply through Desalination and Wastewater Reuse)
Figures

Figure 1

Open AccessArticle The Cost of Clean Water in the Delaware River Basin (USA)
Water 2018, 10(2), 95; doi:10.3390/w10020095
Received: 22 September 2017 / Revised: 31 October 2017 / Accepted: 8 January 2018 / Published: 24 January 2018
PDF Full-text (5590 KB) | HTML Full-text | XML Full-text
Abstract
The Delaware River has made a marked recovery in the half-century since the adoption of the Delaware River Basin Commission (DRBC) Compact in 1961 and passage of the Federal Clean Water Act amendments during the 1970s. During the 1960s, the DRBC set a
[...] Read more.
The Delaware River has made a marked recovery in the half-century since the adoption of the Delaware River Basin Commission (DRBC) Compact in 1961 and passage of the Federal Clean Water Act amendments during the 1970s. During the 1960s, the DRBC set a 3.5 mg/L dissolved oxygen criterion for the river based on an economic analysis that concluded that a waste load abatement program designed to meet fishable water quality goals would generate significant recreational and environmental benefits. Scientists with the Delaware Estuary Program have recently called for raising the 1960s dissolved oxygen criterion along the Delaware River from 3.5 mg/L to 5.0 mg/L to protect anadromous American shad and Atlantic sturgeon, and address the prospect of rising temperatures, sea levels, and salinity in the estuary. This research concludes, through a nitrogen marginal abatement cost (MAC) analysis, that it would be cost-effective to raise dissolved oxygen levels to meet a more stringent standard by prioritizing agricultural conservation and some wastewater treatment investments in the Delaware River watershed to remove 90% of the nitrogen load by 13.6 million kg N/year (30 million lb N/year) for just 35% ($160 million) of the $449 million total cost. The annual least cost to reduce nitrogen loads and raise dissolved oxygen levels to meet more stringent water quality standards in the Delaware River totals $45 million for atmospheric NOX reduction, $130 million for wastewater treatment, $132 million for agriculture conservation, and $141 million for urban stormwater retrofitting. This 21st century least cost analysis estimates that an annual investment of $50 million is needed to reduce pollutant loads in the Delaware River to raise dissolved oxygen levels to 4.0 mg/L, $150 million is needed for dissolved oxygen levels to reach 4.5 mg/L, and $449 million is needed for dissolved oxygen levels to reach 5.0 mg/L. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Sorption of Arsenic from Desalination Concentrate onto Drinking Water Treatment Solids: Operating Conditions and Kinetics
Water 2018, 10(2), 96; doi:10.3390/w10020096
Received: 31 December 2017 / Revised: 21 January 2018 / Accepted: 22 January 2018 / Published: 24 January 2018
PDF Full-text (1468 KB) | HTML Full-text | XML Full-text
Abstract
Selective removal of arsenic from aqueous solutions with high salinity is required for safe disposal of the concentrate and protection of the environment. The use of drinking water treatment solids (DWTS) to remove arsenic from reverse osmosis (RO) concentrate was studied by batch
[...] Read more.
Selective removal of arsenic from aqueous solutions with high salinity is required for safe disposal of the concentrate and protection of the environment. The use of drinking water treatment solids (DWTS) to remove arsenic from reverse osmosis (RO) concentrate was studied by batch sorption experiments. The impacts of solution chemistry, contact time, sorbent dosage, and arsenic concentration on sorption were investigated, and arsenic sorption kinetics and isotherms were modeled. The results indicated that DWTS were effective in removing arsenic from RO concentrate. The arsenic sorption process followed a pseudo-second-order kinetic model. Multilayer adsorption was simulated by Freundlich equation. The maximum sorption capacities were calculated to be 170 mg arsenic per gram of DWTS. Arsenic sorption was enhanced by surface precipitation onto the DWTS due to the high amount of calcium in the RO concentrate and the formation of ternary complexes between arsenic and natural organic matter (NOM) bound by the polyvalent cations in DWTS. The interactions between arsenic and NOM in the solid phase and aqueous phase exhibited two-sided effects on arsenic sorption onto DWTS. NOM in aqueous solution hindered the arsenic sorption onto DWTS, while the high organic matter content in solid DWTS phase enhanced arsenic sorption. Full article
(This article belongs to the Special Issue Desalination and Water Treatment)
Figures

Open AccessArticle Tracers Reveal Recharge Elevations, Groundwater Flow Paths and Travel Times on Mount Shasta, California
Water 2018, 10(2), 97; doi:10.3390/w10020097
Received: 31 October 2017 / Revised: 17 January 2018 / Accepted: 18 January 2018 / Published: 23 January 2018
PDF Full-text (7378 KB) | HTML Full-text | XML Full-text
Abstract
Mount Shasta (4322 m) is famous for its spring water. Water for municipal, domestic and industrial use is obtained from local springs and wells, fed by annual snow melt and sustained perennially by the groundwater flow system. We examined geochemical and isotopic tracers
[...] Read more.
Mount Shasta (4322 m) is famous for its spring water. Water for municipal, domestic and industrial use is obtained from local springs and wells, fed by annual snow melt and sustained perennially by the groundwater flow system. We examined geochemical and isotopic tracers in samples from wells and springs on Mount Shasta, at the headwaters of the Sacramento River, in order to better understand the hydrologic system. The topographic relief in the study area imparts robust signatures of recharge elevation to both stable isotopes of the water molecule (δ18O and δD) and to dissolved noble gases, offering tools to identify recharge areas and delineate groundwater flow paths. Recharge elevations determined using stable isotopes and noble gas recharge temperatures are in close agreement and indicate that most snowmelt infiltrates at elevations between 2000 m and 2900 m, which coincides with areas of thin soils and barren land cover. Large springs in Mt Shasta City discharge at an elevation more than 1600 m lower. High elevation springs (>2000 m) yield very young water (<2 years) while lower elevation wells (1000–1500 m) produce water with a residence time ranging from 6 years to over 60 years, based on observed tritium activities. Upslope movement of the tree line in the identified recharge elevation range due to a warming climate is likely to decrease infiltration and recharge, which will decrease spring discharge and production at wells, albeit with a time lag dependent upon the length of groundwater flow paths. Full article
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
Figures

Figure 1

Open AccessArticle A Paradigm Shift in Water Quality Governance in a Transitional Context: A Critical Study about the Empowerment of Local Governance in Georgia
Water 2018, 10(2), 98; doi:10.3390/w10020098
Received: 30 November 2017 / Revised: 14 January 2018 / Accepted: 17 January 2018 / Published: 24 January 2018
Cited by 1 | PDF Full-text (2312 KB) | HTML Full-text | XML Full-text
Abstract
The management of water quality is an important part of natural resource governance. Assurance of water quality therefore requires formulation of the regulatory framework and institutional process. Water quality-related problems and their management are mainly recognized as local responsibilities in Integrated Water Resources
[...] Read more.
The management of water quality is an important part of natural resource governance. Assurance of water quality therefore requires formulation of the regulatory framework and institutional process. Water quality-related problems and their management are mainly recognized as local responsibilities in Integrated Water Resources Management (IWRM). The politics of environmental policy-making should consider the political economic dynamics and socio-ecological patterns. Decentralization by providing more power to the local level and moving to a new spatial management system that is based on water basins are the two strong entreaties in the new water governance paradigm. Transitional countries facing rapid institutional adjustment, restructuring of regulations, and political-economic changes are encountering these demands internally and externally in their policy formulations. In this context, this study critically examines the case of Georgia, a transitional country. In particular, the focus is on how local governance entities can be empowered and what obstacles water quality governance encounters in Georgia. Qualitative research design is the main research method implemented in this study. The key findings from the research analysis are as follows: the existing regulations and governance system do not facilitate the active engagement of local entities in water quality governance. The application of new water polices may fail again if a top-down governance model is put in place that only creates a narrow space for local governance entities to effectively govern water quality. Full article
Figures

Figure 1

Open AccessArticle High-Strength Domestic Wastewater Treatment and Reuse with Onsite Passive Methods
Water 2018, 10(2), 99; doi:10.3390/w10020099
Received: 10 October 2017 / Revised: 18 December 2017 / Accepted: 19 December 2017 / Published: 25 January 2018
Cited by 1 | PDF Full-text (1208 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes the preliminary monitoring results of an onsite pilot wastewater treatment plant consisting of a septic tank, an anaerobic up-flow filter, and a horizontal subsurface flow wetland system planted with Agapanthus africanus. The system was designed to treat heavily polluted
[...] Read more.
This paper describes the preliminary monitoring results of an onsite pilot wastewater treatment plant consisting of a septic tank, an anaerobic up-flow filter, and a horizontal subsurface flow wetland system planted with Agapanthus africanus. The system was designed to treat heavily polluted domestic wastewater produced in a research and development (R&D) center, reaching additional goals of zero energy consumption and eliminating the use of chemical additives. First water quality data shows that organic load in the treated sewage were removed achieving more than 95% efficiency. Nutrients were removed by almost 50%, and fecal and total coliform counts decreased by 99.96%. The results were compared to official Mexican regulations for wastewater discharged into lakes and reservoirs complied with all of them except for nutrients. In this pilot project, the resulting treated wastewater was directly reused for watering the green areas of the R&D center. The result was that the excess of nutrients improved the quality of the grass, avoiding the use of synthetic fertilizers, and created a wetland habitat for small wildlife species living in the area. Full article
(This article belongs to the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse)
Figures

Figure 1

Open AccessArticle Quantification of Groundwater Discharge in a Subalpine Stream Using Radon-222
Water 2018, 10(2), 100; doi:10.3390/w10020100
Received: 4 November 2017 / Revised: 21 January 2018 / Accepted: 22 January 2018 / Published: 25 January 2018
PDF Full-text (7059 KB) | HTML Full-text | XML Full-text
Abstract
During the dry months of the water year in Mediterranean climates, groundwater influx is essential to perennial streams for sustaining ecosystem health and regulating water temperature. Predicted earlier peak flow due to climate change may result in decreased baseflow and the transformation of
[...] Read more.
During the dry months of the water year in Mediterranean climates, groundwater influx is essential to perennial streams for sustaining ecosystem health and regulating water temperature. Predicted earlier peak flow due to climate change may result in decreased baseflow and the transformation of perennial streams to intermittent streams. In this study, naturally occurring radon-222 (222Rn) was used as a tracer of groundwater influx to Martis Creek, a subalpine stream near Lake Tahoe, CA. Groundwater 222Rn is estimated based on measurements of 222Rn activity in nearby deep wells and springs. To determine the degassing constant (needed for quantification of water and gas flux), an extrinsic tracer, xenon (Xe), was introduced to the stream and monitored at eight downstream locations. The degassing constant for 222Rn is based on the degassing constant for Xe, and was determined to be 1.9–9.0 m/day. Applying a simple model in which stream 222Rn activity is a balance between the main 222Rn source (groundwater) and sink (volatilization), the influx in reaches of the upstream portion of Martis Creek was calculated to be <1 to 15 m3/day/m, which cumulatively constitutes a significant portion of the stream discharge. Experiments constraining 222Rn emanation from hyporheic zone sediments suggest that this should be considered a maximum rate of influx. Groundwater influx is typically difficult to identify and quantify, and the method employed here is useful for identifying locations for focused stream flow measurements, for formulating a water budget, and for quantifying streamwater–groundwater interaction. Full article
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
Figures

Figure 1

Open AccessArticle Submerged Fixed Floating Structure under the Action of Surface Current
Water 2018, 10(2), 102; doi:10.3390/w10020102
Received: 17 November 2017 / Revised: 23 January 2018 / Accepted: 23 January 2018 / Published: 26 January 2018
PDF Full-text (2606 KB) | HTML Full-text | XML Full-text
Abstract
The implementation of floating structures has increased with the construction of new sluices for flood control. The overturning moment of floating structure and its influencing factors are the important parameters that determine the structural safety. It is essential to understand the overturning characteristics
[...] Read more.
The implementation of floating structures has increased with the construction of new sluices for flood control. The overturning moment of floating structure and its influencing factors are the important parameters that determine the structural safety. It is essential to understand the overturning characteristics of these structures in currents. Based on hydrodynamic theory and equilibrium analysis, the hydraulic characteristics of a floating structure are discussed by means of theoretical analysis and experiments. A formula for the overturning moment is developed in terms of the time-averaged pressure on the structure. The corresponding parametric study aims to assess the effects of flow velocities, vertical positions, shape ratios and water levels on the overturning moment. The experimental results show that hydrodynamic factors have a significant influence on the overturning of the structure. Furthermore, a relationship is obtained between the overturning moment and the contributing parameters according to dimensional analysis and the linear fitting method of multidimensional ordinary least squares (OLS). The results predicted by the formula agree with the experimental results, demonstrating the potential for general applicability. Full article
Figures

Figure 1

Open AccessArticle Numerical and Physical Investigation of the Performance of Turbulence Modeling Schemes around a Scour Hole Downstream of a Fixed Bed Protection
Water 2018, 10(2), 103; doi:10.3390/w10020103
Received: 17 November 2017 / Revised: 19 January 2018 / Accepted: 22 January 2018 / Published: 26 January 2018
PDF Full-text (2175 KB) | HTML Full-text | XML Full-text
Abstract
Local scour occurs around hydraulic structures such as piers, bed protections, and dikes. In this study, the turbulent flow around a scour hole downstream of a fixed bed protection was investigated. Numerical modeling with OpenFOAM was applied to compute the flow velocity and
[...] Read more.
Local scour occurs around hydraulic structures such as piers, bed protections, and dikes. In this study, the turbulent flow around a scour hole downstream of a fixed bed protection was investigated. Numerical modeling with OpenFOAM was applied to compute the flow velocity and turbulent kinetic energy with respect to flow conditions by changing water depth. A proper computational grid size and time step for simulations are suggested. Three typical turbulent models, k ε , k ω , and k ω S S T , were considered for simulating the flow around a scour hole. The performances of the three models were evaluated by comparing them with numerical and laboratory experimental results. Mean flow velocity profiles computed by the three turbulent schemes are generally in good agreement with laboratory measurements. However, k ω has a limitation in simulating reversal flow in the scour hole, and the k ε model does not predict turbulent kinetic energy well near the bottom. Thus, this study found that the most suitable turbulent model for simulating flow around a scour hole downstream of a fixed bed protection is the k ω S S T model. Full article
Figures

Figure 1

Open AccessArticle Occurrence, Distribution, and Risk Assessment of Antibiotics in a Subtropical River-Reservoir System
Water 2018, 10(2), 104; doi:10.3390/w10020104
Received: 25 November 2017 / Revised: 9 January 2018 / Accepted: 23 January 2018 / Published: 26 January 2018
PDF Full-text (2277 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Antibiotic pollutions in the aquatic environment have attracted widespread attention due to their ubiquitous distribution and antibacterial properties. The occurrence, distribution, and ecological risk assessment of 17 common antibiotics in this study were preformed in a vital drinking water source represented as a
[...] Read more.
Antibiotic pollutions in the aquatic environment have attracted widespread attention due to their ubiquitous distribution and antibacterial properties. The occurrence, distribution, and ecological risk assessment of 17 common antibiotics in this study were preformed in a vital drinking water source represented as a river-reservoir system in South China. In general, 15 antibiotics were detected at least once in the watershed, with the total concentrations of antibiotics in the water samples ranging from 193.6 to 863.3 ng/L and 115.1 to 278.2 μg/kg in the sediment samples. For the water samples, higher rain runoff may contribute to the levels of total concentration in the river system, while perennial anthropic activity associated with the usage pattern of antibiotics may be an important factor determining similar sources and release mechanisms of antibiotics in the riparian environment. Meanwhile, the reservoir system could act as a stable reactor to influence the level and composition of antibiotics exported from the river system. For the sediment samples, hydrological factor in the reservoir may influence the antibiotic distributions along with seasonal variation. Ecological risk assessment revealed that tetracycline and ciprofloxacin could pose high risks in the aquatic environment. Taken together, further investigations should be performed to elaborate the environmental behaviors of antibiotics in the river-reservoir system, especially in drinking water sources. Full article
(This article belongs to the Special Issue Antimicrobial Resistance in Environmental Waters)
Figures

Figure 1

Open AccessArticle Short-Term Effects of Drying-Rewetting and Long-Term Effects of Nutrient Loading on Periphyton N:P Stoichiometry
Water 2018, 10(2), 105; doi:10.3390/w10020105
Received: 31 October 2017 / Revised: 22 December 2017 / Accepted: 18 January 2018 / Published: 26 January 2018
PDF Full-text (2596 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Nitrogen (N) and phosphorus (P) concentrations and N:P ratios critically influence periphyton productivity and nutrient cycling in aquatic ecosystems. In coastal wetlands, variations in hydrology and water source (fresh or marine) influence nutrient availability, but short-term effects of drying and rewetting and long-term
[...] Read more.
Nitrogen (N) and phosphorus (P) concentrations and N:P ratios critically influence periphyton productivity and nutrient cycling in aquatic ecosystems. In coastal wetlands, variations in hydrology and water source (fresh or marine) influence nutrient availability, but short-term effects of drying and rewetting and long-term effects of nutrient exposure on periphyton nutrient retention are uncertain. An outdoor microcosm experiment simulated short-term exposure to variation in drying-rewetting frequency on periphyton mat nutrient retention. A 13-year dataset from freshwater marshes of the Florida Everglades was examined for the effect of long-term proximity to different N and P sources on mat-forming periphyton nutrient standing stocks and stoichiometry. Field sites were selected from one drainage with shorter hydroperiod and higher connectivity to freshwater anthropogenic nutrient supplies (Taylor Slough/Panhandle, TS/Ph) and another drainage with longer hydroperiod and higher connectivity to marine nutrient supplies (Shark River Slough, SRS). Total P, but not total N, increased in periphyton mats exposed to both low and high drying-rewetting frequency with respect to the control mats in our experimental microcosm. In SRS, N:P ratios slightly decreased downstream due to marine nutrient supplies, while TS/Ph increased. Mats exposed to short-term drying-rewetting had higher nutrient retention, similar to nutrient standing stocks from long-term field data. Periphyton mat microbial communities may undergo community shifts upon drying-rewetting and chronic exposure to nutrient loads. Additional work on microbial species composition may further explain how periphyton communities interact with drying-rewetting dynamics to influence nutrient cycling and retention in wetlands. Full article
Figures

Figure 1

Open AccessArticle Cross-Analysis of Land and Runoff Variations in Response to Urbanization on Basin, Watershed, and City Scales with/without Green Infrastructures
Water 2018, 10(2), 106; doi:10.3390/w10020106
Received: 13 December 2017 / Revised: 10 January 2018 / Accepted: 22 January 2018 / Published: 26 January 2018
PDF Full-text (10328 KB) | HTML Full-text | XML Full-text
Abstract
Evaluating land and runoff variations caused by urbanization is crucial to ensure the safety of people living in highly developed areas. Based on spatial scales, runoff analysis involves different methods associated with the interpretation of land cover and land use, the application of
[...] Read more.
Evaluating land and runoff variations caused by urbanization is crucial to ensure the safety of people living in highly developed areas. Based on spatial scales, runoff analysis involves different methods associated with the interpretation of land cover and land use, the application of hydrological models, and the consideration of flood mitigation measures. Most studies have focused on analyzing the phenomenon on a certain scale by using a single data source and a specific model without discussing mutual influences. In this study, the runoff changes caused by urbanization are assessed and cross-analyzed on three sizes of study areas in the Zhuoshui River Basin in Taiwan, including basin (large), watershed (medium), and city (small) scales. The results demonstrate that, on the basin scale, land-cover changes interpreted from satellite images are very helpful for identifying the watersheds with urbanization hotspots that might have larger runoff outputs. However, on the watershed scale, the resolution of the land-cover data is too low, and land-cover data should be replaced by investigated land-use data for sophisticated hydrological modeling. The mixed usage of land-cover and land-use data is not recommended because large discrepancies occur when determining hydrological parameters for runoff simulation. According to present and future land-use scenarios, the influence of urbanization on runoff is simulated by HEC-1 and SWMM on watershed and city scales, respectively. The results of both models are in agreement and show that runoff peaks will obviously increase as a result of urbanization from 2008 to 2030. For low return periods, the increase in runoff as a result of urbanization is more significant and the city’s contribution to runoff is much larger than its area. Through statistical regression, the watershed runoff simulated by HEC-1 can be perfectly predicted by the city runoff simulated by SWMM in combination with other land/rainfall parameters. On the city scale, the installation of LID satisfactorily reduces the runoff peaks to pre-urbanization levels for low return periods, but the effects of LID are not as positive and are debatable for higher return periods. These findings can be used to realize the applicability and limitations of different approaches for analyzing and mitigating urbanization-induced runoff in the process of constructing a sponge city. Full article
(This article belongs to the Special Issue Sponge Cities: Emerging Approaches, Challenges and Opportunities)
Figures

Figure 1

Open AccessArticle Defining Seasonal Functional Traits of a Freshwater Zooplankton Community Using δ13C and δ15N Stable Isotope Analysis
Water 2018, 10(2), 108; doi:10.3390/w10020108
Received: 30 November 2017 / Revised: 17 January 2018 / Accepted: 23 January 2018 / Published: 27 January 2018
Cited by 1 | PDF Full-text (1519 KB) | HTML Full-text | XML Full-text
Abstract
Functional-based approaches are increasingly being used to define the functional diversity of aquatic ecosystems. In this study, we proposed the use of δ13C and δ15N stable isotopes as a proxy of zooplankton functional traits in Lake Maggiore, a large,
[...] Read more.
Functional-based approaches are increasingly being used to define the functional diversity of aquatic ecosystems. In this study, we proposed the use of δ13C and δ15N stable isotopes as a proxy of zooplankton functional traits in Lake Maggiore, a large, deep subalpine Italian lake. We analyzed the seasonal pattern of δ13C and δ15N signatures of different crustacean zooplankton taxa to determine food sources, preferred habitats, and trophic positions of species throughout one year. The cladocerans Daphnia longispina galeata gr., Diaphanosoma brachyurum, and Eubosmina longispina were grouped into a primary consumer functional group from their δ13C and δ15N isotopic signatures, but while the former two species shared the same food sources, the latter exhibited a more selective feeding strategy. Cyclopoid copepods occupied a distinct functional group from the other secondary consumers, being the most 15N enriched group in the lake. The δ15N signature of calanoid copepods showed trophic enrichment in comparison to Daphnia and Eubosmina and linear mixing model results confirmed a predator-prey relationship. In our study, we have demonstrated that the use of δ13C and δ15N stable isotopes represented an effective tool to define ecological roles of freshwater zooplankton species and to determine functional diversity in a lake. Full article
Figures

Figure 1

Open AccessArticle Impact of Hydrodynamic Reconfiguration with Baffles on Treatment Performance in Waste Stabilisation Ponds: A Full-Scale Experiment
Water 2018, 10(2), 109; doi:10.3390/w10020109
Received: 5 January 2018 / Revised: 21 January 2018 / Accepted: 23 January 2018 / Published: 27 January 2018
PDF Full-text (7236 KB) | HTML Full-text | XML Full-text
Abstract
Wastewater infrastructure is expensive to build and maintain, and there is a need to focus on improving and modernising existing infrastructure before large capital investments are made to service future population needs. Waste stabilisation ponds (WSPs) are used worldwide for the treatment of
[...] Read more.
Wastewater infrastructure is expensive to build and maintain, and there is a need to focus on improving and modernising existing infrastructure before large capital investments are made to service future population needs. Waste stabilisation ponds (WSPs) are used worldwide for the treatment of wastewater, but their performance is significantly affected by poor hydraulic control. Hydraulic reconfiguration of ponds is a possible solution to this problem, whereby the flow is controlled and short-circuiting is reduced. There is evidence to suggest that this approach has the potential to increase treatment performance, however in the absence of full-scale validation it is difficult to generalise this to a wide range of sites. For example, there is no consensus on the best baffle configuration to optimise hydraulic performance. The main objective of this study was to conduct a full-scale experiment of baffles in a WSP, and to investigate their impact on hydraulic performance. To achieve this objective, the approach combined high-resolution pond bathymetry and 2D hydrodynamic modelling, assessed with hydraulic indices, to determine the optimal baffle configuration for the site; it was shown that three baffles perpendicular to the inflow provided the greatest increase (up to 24%) in mean residence time. This configuration was then implemented in a working WSP. The effects of the baffles on the pond were then assessed using a combination of field tracer testing, revealing an increase in mean residence time of at least 20%, and further hydrodynamic modelling. Through the addition of wind data into the hydrodynamic model, it is shown that baffles not only improve the flow, but also attenuate the effect of wind on pond hydraulics. While the conclusions of this study are site-specific, the implementation of site-specific solutions is important for progress towards optimal pond design. The approach developed here is easily transferrable for use on other sites, and will enhance our ability to plan, design and operate WSP systems in the future. Full article
Figures

Open AccessArticle A Numerical Approach to Predict Water Levels in Ungauged Regions—Case Study of the Meghna River Estuary, Bangladesh
Water 2018, 10(2), 110; doi:10.3390/w10020110
Received: 26 October 2017 / Revised: 17 January 2018 / Accepted: 17 January 2018 / Published: 27 January 2018
PDF Full-text (18665 KB) | HTML Full-text | XML Full-text
Abstract
Quantitative flood frequency investigation in a large estuary is somewhat challenging by numerical modelling, because the model optimization depends on the appropriate physical and hydrodynamic properties of the estuarine river. This study attempts to solve the bathymetry configurations of the Meghna River estuary
[...] Read more.
Quantitative flood frequency investigation in a large estuary is somewhat challenging by numerical modelling, because the model optimization depends on the appropriate physical and hydrodynamic properties of the estuarine river. This study attempts to solve the bathymetry configurations of the Meghna River estuary and the assimilation of flow data, which exposed an important role in water level prediction. Upstream flow rates and nonlinear semidiurnal tides have an impact on the instability of the flow in this estuarine river. A large amount of flow accumulates in the upstream confluence against or in favor of tides during the rainy season from the adjacent river basins and significantly moves in the Bay of Bengal. The aim of this study is to predict water levels in the un-gauged regions of the Meghna River estuary. A numerical technique was developed using Mike21 flexible mesh, comprising shallow water hydrodynamic components in the estuary. Subsequently, log-normal distribution was employed to analyze the flood magnitudes among the ungauged stations of the estuary. The calibration results comprised with the observed water levels adequately. In conclusion, these water level prediction results can be applied to alleviate the coastal land from extreme flooding and to design hydraulic structures in the narrow streams. Full article
Figures

Figure 1

Open AccessArticle Streambank Alluvial Unit Contributions to Suspended Sediment and Total Phosphorus Loads, Walnut Creek, Iowa, USA
Water 2018, 10(2), 111; doi:10.3390/w10020111
Received: 16 January 2018 / Revised: 23 January 2018 / Accepted: 25 January 2018 / Published: 28 January 2018
PDF Full-text (5368 KB) | HTML Full-text | XML Full-text
Abstract
Streambank erosion may represent a significant source of sediment and phosphorus (P) to overall watershed loads; however, watershed-scale quantification of contributions is rare. In addition, streambanks are often comprised of highly variable stratigraphic source materials (e.g., alluvial deposits), which may differentially impact in-channel
[...] Read more.
Streambank erosion may represent a significant source of sediment and phosphorus (P) to overall watershed loads; however, watershed-scale quantification of contributions is rare. In addition, streambanks are often comprised of highly variable stratigraphic source materials (e.g., alluvial deposits), which may differentially impact in-channel P dynamics once eroded. The objective of this study was to quantify sediment and total phosphorus (TP) losses from four materials comprising streambanks within a 5218 ha watershed in Iowa, USA. Streambank-face surveys, erosion pins, and soil analyses were used to quantify surface area representation, recession, and losses of sediment and TP over a two-year period. Cumulative, whole-bank gross mean recession totaled 18.6 cm over two years, and material-specific gross mean recession ranged from 15.5 to 64.1 cm. Cumulative, whole-bank mean gross mass losses totaled 0.28 Mg sediment and 0.7 × 10−5 Mg TP per meter channel length. Annual sediment losses equated to 4–44% of historic suspended sediment loads. Stratigraphy was significant in gross material erosion and losses, with lower materials (i.e., bank toe region) exhibiting the greatest recession rates and cumulative recession. Weathered/colluvial material dominated total bank face surface area (88.3%), and contributed the greatest proportion of sediment and TP mass loss (66, 68%, respectively) versus other streambank materials. Full article
(This article belongs to the Special Issue Streambank Erosion: Monitoring, Modeling and Management)
Figures

Open AccessArticle Spatial and Temporal Analysis of Rainfall Concentration Using the Gini Index and PCI
Water 2018, 10(2), 112; doi:10.3390/w10020112
Received: 16 November 2017 / Revised: 22 January 2018 / Accepted: 22 January 2018 / Published: 28 January 2018
PDF Full-text (5635 KB) | HTML Full-text | XML Full-text
Abstract
This study aims to determine if there is variation in precipitation concentrations in Chile. We analyzed daily and monthly records from 89 pluviometric stations in the period 1970–2016 and distributed between 29°12′ S and 39°30′ S. This area was divided into two climatic
[...] Read more.
This study aims to determine if there is variation in precipitation concentrations in Chile. We analyzed daily and monthly records from 89 pluviometric stations in the period 1970–2016 and distributed between 29°12′ S and 39°30′ S. This area was divided into two climatic zones: arid–semiarid and humid–subhumid. For each station, the Gini coefficient or Gini Index (GI), the precipitation concentration index (PCI), and the maximum annual precipitation intensity in a 24-h duration were calculated. These series of annual values were analyzed with the Mann–Kendall test with 5% error. Overall, it was noted that positive trends in the GI are present in both areas, although most were not found to be significant. In the case of PCI, the presence of positive trends is only present in the arid–semiarid zone; in the humid–subhumid zone, negative trends were mostly observed, although none of them were significant. Although no significant changes in all indices are evident, the particular case of the GI in the humid–subhumid zone stands out, where mostly positive trends were found (91.1%), of which 35.6% were significant. This would indicate that precipitation is more likely to be concentrated on a daily scale. Full article
Figures

Figure 1

Open AccessArticle Seasonal Variability and Evolution of Glaciochemistry at An Alpine Temperate Glacier on the Southeastern Tibetan Plateau
Water 2018, 10(2), 114; doi:10.3390/w10020114
Received: 4 October 2017 / Revised: 7 January 2018 / Accepted: 25 January 2018 / Published: 29 January 2018
PDF Full-text (1731 KB) | HTML Full-text | XML Full-text
Abstract
Temperate glaciers are highly sensitive to climatic and environmental changes. Studying the chemical composition of snow, firn, and ice on temperate glaciers is important for understanding the variations in atmospheric circulation patterns, deposition conditions, and melting processes. To define snowpack chemistry and environmental
[...] Read more.
Temperate glaciers are highly sensitive to climatic and environmental changes. Studying the chemical composition of snow, firn, and ice on temperate glaciers is important for understanding the variations in atmospheric circulation patterns, deposition conditions, and melting processes. To define snowpack chemistry and environmental significance, seven snowpacks (one snowpack in late autumn, two in winter, two in spring, and two in summer) were sampled in 2008/2009 on Baishui Glacier No. 1 in Mt. Yulong. Soluble ions in the winter snowpacks showed low values in the middle part but high values in the lower and upper parts, influenced by the atmospheric deposition of snow accumulation. The larger variations of ionic concentrations in the spring snowpacks were associated with the variable atmospheric patterns with high dust content in spring, leading to high ionic concentrations in the upper snowpack. Strong meltwater percolation resulted in quick migration and redistribution of ions for the profiles during the monsoon period. The ion elution sequence was Ca2+ > SO42− > NH4+ > K+ > NO3 > Na+ > Cl > Mg2+. Factor analysis showed that NO3, SO42−, NH4+ were mainly supplied by wet deposition-plus-anthropogenic input, while Cl and Na+ originated from marine sources. Ca2+ and Mg2+ had multiple sources and the local terrestrial source was important because of locally exposed carbonate. The results suggest that chemical concentrations reflect mainly impurities supplied by atmospheric circulation and precipitation during periods of snow accumulation, as well as during the melting process. Full article
Figures

Figure 1

Open AccessArticle Occurrence, Seasonal Variation and Risk Assessment of Antibiotics in Qingcaosha Reservoir
Water 2018, 10(2), 115; doi:10.3390/w10020115
Received: 28 November 2017 / Revised: 6 January 2018 / Accepted: 19 January 2018 / Published: 29 January 2018
PDF Full-text (17605 KB) | HTML Full-text | XML Full-text
Abstract
Qingcaosha Reservoir is an important drinking water source in Shanghai. The occurrence of five groups of antibiotics was investigated in the surface water of this reservoir over a one-year period. Seventeen antibiotics were selected in this study based on their significant usage in
[...] Read more.
Qingcaosha Reservoir is an important drinking water source in Shanghai. The occurrence of five groups of antibiotics was investigated in the surface water of this reservoir over a one-year period. Seventeen antibiotics were selected in this study based on their significant usage in China. Of these antibiotics, 16 were detected, while oxytetracycline was not detected in any sampling site. The detected frequency of tylosin was only 47.92% while the other 15 antibiotics were above 81.25%. The dominant antibiotic was different in four seasons: norfloxacin was dominant in spring, and penicillinV was dominant in summer, autumn and winter, with medium concentrations of 124.10 ng/L, 89.91 ng/L, 180.28 ng/L, and 216.43 ng/L, respectively. The concentrations and detection frequencies of antibiotics were notably higher in winter than in other seasons, demonstrating that low temperature and low flow may result in the persistence of antibiotics in the aquatic environment. Risk assessment suggested that norfloxacin, ciprofloxacin, penicillinV, and doxycycline in the surface water presented high ecological risks. Full article
(This article belongs to the Special Issue Antimicrobial Resistance in Environmental Waters)
Figures

Figure 1

Open AccessArticle Roof Rainwater Harvesting in Central Mexico: Uses, Benefits, and Factors of Adoption
Water 2018, 10(2), 116; doi:10.3390/w10020116
Received: 20 December 2017 / Revised: 17 January 2018 / Accepted: 22 January 2018 / Published: 29 January 2018
PDF Full-text (1089 KB) | HTML Full-text | XML Full-text
Abstract
This study was carried out in rural communities in the state of Guanajuato, in central Mexico. A questionnaire was directly applied to users of rainwater (RW) to identify the uses, water consumption, and perception towards RW and traditional supply sources, for the purpose
[...] Read more.
This study was carried out in rural communities in the state of Guanajuato, in central Mexico. A questionnaire was directly applied to users of rainwater (RW) to identify the uses, water consumption, and perception towards RW and traditional supply sources, for the purpose of evaluating the relevance of RW in different situations as an alternative supply, as well as the factors that affect the adoption and use of this source. RW turned out to be the users’ main water source, and functions as a tool to increase the knowledge and perception of the rainy season and other factors. The respondents identified at least one benefit from the use of RW; the most important benefits were the watering of plants and gardens, avoiding the purchase of water from tank trucks, avoiding the need to fetch water, among others. In the localities studied, where the traditional water supply is either deficient or totally lacking, the use and acceptance of RW has increased. Economic support and training to install systems were key factors for those systems’ installation in the communities. These findings may assist future projects to promote the use of RW harvesting at the domestic level and increase the water supply. Full article
Figures

Figure 1

Open AccessArticle Using DPSIR and Balances to Support Water Governance
Water 2018, 10(2), 118; doi:10.3390/w10020118
Received: 9 November 2017 / Revised: 22 January 2018 / Accepted: 24 January 2018 / Published: 29 January 2018
PDF Full-text (594 KB) | HTML Full-text | XML Full-text
Abstract
The DPSIR framework has proven to be an effective communication tool, but has become subject to criticism upon increasing practical application. It is assumed that this is the consequence of the combination of terminological unclarity, absence of a methodological description for analyzing disturbances,
[...] Read more.
The DPSIR framework has proven to be an effective communication tool, but has become subject to criticism upon increasing practical application. It is assumed that this is the consequence of the combination of terminological unclarity, absence of a methodological description for analyzing disturbances, and a confined conceptual basis when dealing with complex environmental issues. DPSIR has been embedded within the broader conceptual Pentatope Model (PTM), by making use of an ‘interface’ called GASI. GASI, which means Governance by Actor–Subject Impact Assessment, deals explicitly with governance as a framework and impact analysis as a process. The result is an extended version of DPSIR. Illustrated by means of a water balance, the importance of a combined PTM–GASI–DPSIR tool for impact assessments to support evidence-based governance is shown. Full article
Figures

Figure 1

Open AccessArticle Comparing Mixed-Media and Conventional Slow-Sand Filters for Arsenic Removal from Groundwater
Water 2018, 10(2), 119; doi:10.3390/w10020119
Received: 13 November 2017 / Revised: 22 December 2017 / Accepted: 8 January 2018 / Published: 29 January 2018
PDF Full-text (2832 KB) | HTML Full-text | XML Full-text
Abstract
Arsenic contamination of groundwater is a major public health concern worldwide. The problem has been reported mainly in southern Asia and, especially, in Bangladesh. Slow-sand filters (SSF) augmented with iron were proven to be a simple, low-cost and decentralized technique for the treatment
[...] Read more.
Arsenic contamination of groundwater is a major public health concern worldwide. The problem has been reported mainly in southern Asia and, especially, in Bangladesh. Slow-sand filters (SSF) augmented with iron were proven to be a simple, low-cost and decentralized technique for the treatment of arsenic-contaminated sources. In this research, three pilot-scale SSF (flowrate 6 L·h−1) were tested regarding their capability of removing arsenic from groundwater in conditions similar to those found in countries like Bangladesh (70 µg As(III) L−1, 26 °C). From the three, two filters were prepared with mixed media, i.e., sand mixed with corrosive iron matter (CIM filter) and iron-coated sand (ICS filter), and a third conventional SSF was used as a reference. The results obtained showed that the CIM filter could remove arsenic below the World Health Organization (WHO) guideline concentration of 10 µg·L−1, even for inlet concentrations above 150 µg·L−1. After 230 days of continuous operation the arsenic concentration in the effluent started increasing, indicating depletion or saturation of the CIM layer. The effluent arsenic concentration, however, never exceeded the Bangladeshi standard of 50 µg·L−1 throughout the whole duration of the experiments. Full article
Figures

Open AccessArticle Impact of Climate Change on Streamflow Hydrology in Headwater Catchments of the Upper Blue Nile Basin, Ethiopia
Water 2018, 10(2), 120; doi:10.3390/w10020120
Received: 5 October 2017 / Revised: 22 January 2018 / Accepted: 24 January 2018 / Published: 29 January 2018
Cited by 2 | PDF Full-text (3248 KB) | HTML Full-text | XML Full-text
Abstract
This study assessed the impact of climate change on water availability and variability in two subbasins in the upper Blue Nile basin of Ethiopia. Downscaled future climate data from HadCM3 of A2 (medium-high) and B2 (medium-low) emission scenarios were compared to the observed
[...] Read more.
This study assessed the impact of climate change on water availability and variability in two subbasins in the upper Blue Nile basin of Ethiopia. Downscaled future climate data from HadCM3 of A2 (medium-high) and B2 (medium-low) emission scenarios were compared to the observed climate data for a baseline period (1961–1990). The emission scenario representing the baseline period was used to predict future climate and as input to a hydrologic model to estimate the impact of future climate on the streamflow at three future time horizons: 2020–2045, 2045–2070 and 2070–2100. Results suggest that medium-high emission scenario best represents the local rainfall and temperature pattern. With A2 scenario, daily maximum/minimum temperature will increase throughout the future time horizons. The minimum and maximum temperature will increase by 3.6 °C and 2.4 °C, respectively, towards the end of the 21st century. Consequently, potential evapotranspiration is expected to increase by 7.8%, although trends in annual rainfall do not show statistically meaningful trends between years. A notable seasonality was found in the rainfall pattern, such that dry season rainfall amounts are likely to increase and wet season rainfall to decrease. The hydrological model indicated that the local hydrology of the study watersheds will be significantly influenced by climate change. Overall, at the end of the century, streamflow will increase in both rivers by up to 64% in dry seasons and decrease by 19% in wet seasons. Full article
Figures

Figure 1

Open AccessArticle Simulating Water Allocation and Cropping Decisions in Yemen’s Abyan Delta Spate Irrigation System
Water 2018, 10(2), 121; doi:10.3390/w10020121
Received: 30 November 2017 / Revised: 28 December 2017 / Accepted: 26 January 2018 / Published: 29 January 2018
PDF Full-text (1951 KB) | HTML Full-text | XML Full-text
Abstract
Agriculture employs more Yemenis than any other sector and spate irrigation is the largest source of irrigation water. Spate irrigation however is growing increasingly difficult to sustain in many areas due to water scarcity and unclear sharing of water amongst users. In some
[...] Read more.
Agriculture employs more Yemenis than any other sector and spate irrigation is the largest source of irrigation water. Spate irrigation however is growing increasingly difficult to sustain in many areas due to water scarcity and unclear sharing of water amongst users. In some areas of Yemen, there are no institutionalised water allocation rules which can lead to water related disputes. Here, we propose a proof-of-concept model to evaluate the impacts of different water allocation patterns to assist in devising allocation rules. The integrated model links simple wadi flow, diversion, and soil moisture-yield simulators to a crop decision model to evaluate impacts of different water allocation rules and their possible implications on local agriculture using preliminary literature data. The crop choice model is an agricultural production model of irrigation command areas where the timing, irrigated area and crop mix is decided each month based on current conditions and expected allocations. The model is applied to Yemen’s Abyan Delta, which has the potential to be the most agriculturally productive region in the country. The water allocation scenarios analysed include upstream priority, downstream priority, equal priority (equal sharing of water shortages), and a user-defined mixed priority that gives precedence to different locations based on the season. Once water is distributed according to one of these allocation patterns, the model determines the profit-maximising plant date and crop selection for 18 irrigated command areas. This aims to estimate the impacts different water allocation strategies could have on livelihoods. Initial results show an equal priority allocation is the most equitable and efficient, with 8% more net benefits than an upstream scenario, 10% more net benefits than a downstream scenario, and 25% more net benefits than a mixed priority. Full article
(This article belongs to the Special Issue Hydroeconomic Analysis for Sustainable Water Management)
Figures

Figure 1

Open AccessArticle A Heuristic Method for Measurement Site Selection in Sewer Systems
Water 2018, 10(2), 122; doi:10.3390/w10020122
Received: 21 December 2017 / Revised: 19 January 2018 / Accepted: 25 January 2018 / Published: 29 January 2018
PDF Full-text (8424 KB) | HTML Full-text | XML Full-text
Abstract
Although calibration of a hydrodynamic model depends on the availability of measurement data representing the system behavior, advice for the planning of necessary measurement campaigns for model calibration is scarce. This work tries to address this question of efficient measurement site selection on
[...] Read more.
Although calibration of a hydrodynamic model depends on the availability of measurement data representing the system behavior, advice for the planning of necessary measurement campaigns for model calibration is scarce. This work tries to address this question of efficient measurement site selection on a network scale for the objective of calibrating a hydrodynamic model case study in Austria. For this, a model-based approach is chosen, as the method should be able to be used before measurement data is available. An existing model is assumed to represent the real system behavior. Based on this extended availability of “measurement data” in every point of the system, different approaches are established to heuristically assess the suitability of one or more pipes in combination as calibration point(s). These approaches intend to find suitable answers to the question of measurement site selection for this specific case study within a relatively short time and with a reasonable computational effort. As a result, the relevance of the spatial distribution of calibration points is highlighted. Furthermore, particular efficient calibration points are identified and further measurement sites in the underlying network are recommended. Full article
(This article belongs to the Special Issue Quantifying Uncertainty in Integrated Catchment Studies)
Figures

Figure 1

Open AccessArticle Mathematical Modeling of Non-Fickian Diffusional Mass Exchange of Radioactive Contaminants in Geological Disposal Formations
Water 2018, 10(2), 123; doi:10.3390/w10020123
Received: 30 July 2017 / Revised: 8 January 2018 / Accepted: 23 January 2018 / Published: 29 January 2018
PDF Full-text (1067 KB) | HTML Full-text | XML Full-text
Abstract
Deep geological repositories for nuclear wastes consist of both engineered and natural geologic barriers to isolate the radioactive material from the human environment. Inappropriate repositories of nuclear waste would cause severe contamination to nearby aquifers. In this complex environment, mass transport of radioactive
[...] Read more.
Deep geological repositories for nuclear wastes consist of both engineered and natural geologic barriers to isolate the radioactive material from the human environment. Inappropriate repositories of nuclear waste would cause severe contamination to nearby aquifers. In this complex environment, mass transport of radioactive contaminants displays anomalous behaviors and often produces power-law tails in breakthrough curves due to spatial heterogeneities in fractured rocks, velocity dispersion, adsorption, and decay of contaminants, which requires more sophisticated models beyond the typical advection-dispersion equation. In this paper, accounting for the mass exchange between a fracture and a porous matrix of complex geometry, the universal equation of mass transport within a fracture is derived. This equation represents the generalization of the previously used models and accounts for anomalous mass exchange between a fracture and porous blocks through the introduction of the integral term of convolution type and fractional derivatives. This equation can be applied for the variety of processes taking place in the complex fractured porous medium, including the transport of radioactive elements. The Laplace transform method was used to obtain the solution of the fractional diffusion equation with a time-dependent source of radioactive contaminant. Full article
Figures

Figure 1

Open AccessFeature PaperArticle A Wall Boundary Condition for the Simulation of a Turbulent Non-Newtonian Domestic Slurry in Pipes
Water 2018, 10(2), 124; doi:10.3390/w10020124
Received: 4 December 2017 / Revised: 17 January 2018 / Accepted: 22 January 2018 / Published: 30 January 2018
PDF Full-text (8466 KB) | HTML Full-text | XML Full-text
Abstract
The concentration (using a lesser amount of water) of domestic slurry promotes resource recovery (nutrients and biomass) while saving water. This article is aimed at developing numerical methods to support engineering processes such as the design and implementation of sewerage for concentrated domestic
[...] Read more.
The concentration (using a lesser amount of water) of domestic slurry promotes resource recovery (nutrients and biomass) while saving water. This article is aimed at developing numerical methods to support engineering processes such as the design and implementation of sewerage for concentrated domestic slurry. The current industrial standard for computational fluid dynamics-based analyses of turbulent flows is Reynolds-averaged Navier–Stokes (RANS) modelling. This is assisted by the wall function approach proposed by Launder and Spalding, which permits the use of under-refined grids near wall boundaries while simulating a wall-bounded flow. Most RANS models combined with wall functions have been successfully validated for turbulent flows of Newtonian fluids. However, our experiments suggest that concentrated domestic slurry shows a Herschel–Bulkley-type non-Newtonian behaviour. Attempts have been made to derive wall functions and turbulence closures for non-Newtonian fluids; however, the resulting laws or equations are either inconsistent across experiments or lack relevant experimental support. Pertinent to this study, laws or equations reported in literature are restricted to a class of non-Newtonian fluids called power law fluids, which, as compared to Herschel–Bulkley fluids, yield at any amount of applied stress. An equivalent law for Herschel–Bulkley fluids that require a minimum-yield stress to flow is yet to be reported in literature. This article presents a theoretically derived (with necessary approximations) law of the wall for Herschel–Bulkley fluids and implements it in a RANS solver using a specified shear approach. This results in a more accurate prediction of the wall shear stress experienced by a circular pipe with a turbulent Herschel–Bulkley fluid flowing through it. The numerical results are compared against data from our experiments and those reported in literature for a range of Reynolds numbers and rheological parameters that are relevant to the prediction of pressure losses in a sewerage transporting non-Newtonian domestic slurry. Nonetheless, the application of this boundary condition could be extended to areas such as chemical and food engineering, wherein turbulent non-Newtonian flows can be found. Full article
(This article belongs to the Special Issue Smart Hydraulics in Wastewater Transport)
Figures

Figure 1

Open AccessArticle Cascade Cropping System with Horticultural and Ornamental Plants under Greenhouse Conditions
Water 2018, 10(2), 125; doi:10.3390/w10020125
Received: 29 December 2017 / Revised: 26 January 2018 / Accepted: 27 January 2018 / Published: 30 January 2018
PDF Full-text (2375 KB) | HTML Full-text | XML Full-text
Abstract
The blending of drainage with water of low electrical conductivity and the sequential reuse of the drainage water are innovative technologies to manage salts in agricultural drainage. Plants of Cucumis melo were grown in coir grow bags, and Rosmarinus officinalis and Cacti spp.
[...] Read more.
The blending of drainage with water of low electrical conductivity and the sequential reuse of the drainage water are innovative technologies to manage salts in agricultural drainage. Plants of Cucumis melo were grown in coir grow bags, and Rosmarinus officinalis and Cacti spp. were grown in pots with a mixture of sphagnum peat-moss and perlite. In order to assess the effect and evolution over time of these water treatments on plant growth and water management and removal of nutrients, three water treatments were applied over a period of eight weeks. These were: (1) standard nutrient solution; (2) blended water treatment (drainage water blended with water of low electrical conductivity (EC)) and (3) sequential reuse of drainage water treatment. During the experimental growing period, samples of water supplies and drainages generated in each water treatment were collected weekly and from these data water volume and nutrient loads were calculated. At the end of the experiment, leaf fresh weight of rosemary plants decreased under the fertigation with the blended and sequential reuse water treatments. Nevertheless, the application of blended and sequentially reused water allowed for the saving of significant amounts of water and nutrients in comparison to the standard nutrient solution treatment. Considering these advantages, we strongly recommend the setting-up of these water treatments in areas with water scarcity such as in the Mediterranean Basin. Full article
Figures

Figure 1

Open AccessArticle Multiple Climate Change Scenarios and Runoff Response in Biliu River
Water 2018, 10(2), 126; doi:10.3390/w10020126
Received: 19 October 2017 / Revised: 25 January 2018 / Accepted: 26 January 2018 / Published: 30 January 2018
Cited by 1 | PDF Full-text (18364 KB) | HTML Full-text | XML Full-text
Abstract
The impacts of temperature and precipitation changes on regional evaporation and runoff characteristics have been investigated for the Biliu River basin, which is located in Liaoning Province, northeast China. Multiple climate change scenarios from phase 3 and phase 5 of the Coupled Model
[...] Read more.
The impacts of temperature and precipitation changes on regional evaporation and runoff characteristics have been investigated for the Biliu River basin, which is located in Liaoning Province, northeast China. Multiple climate change scenarios from phase 3 and phase 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5) (21 scenarios in total) were utilized. A calibrated hydrologic model—SWAT model—was used to simulate future discharges based on downscaled climate data through a validated morphing method. Results show that both annual temperature and precipitation increase under most of the CMIP3 and CMIP5 scenarios, and increase more in the far future (2041–2065) than in the near future (2016–2040). These changes in precipitation and temperature lead to an increase in evaporation under 19 scenarios and a decrease in runoff under two-thirds of the selected scenarios. Compared to CMIP3, CMIP5 scenarios show higher temperature and wider ranges of changes in precipitation and runoff. The results provide important information on the impacts of global climate change on water resources availability in the Biliu River basin, which is beneficial for the planning and management of water resources in this region. Full article
(This article belongs to the Special Issue Adaptive Catchment Management and Reservoir Operation)
Figures

Figure 1

Open AccessArticle Consumption of Free Chlorine in an Aqueduct Scheme with Low Protection: Case Study of the New Aqueduct Simbrivio-Castelli (NASC), Italy
Water 2018, 10(2), 127; doi:10.3390/w10020127
Received: 19 November 2017 / Revised: 10 January 2018 / Accepted: 26 January 2018 / Published: 30 January 2018
PDF Full-text (1632 KB) | HTML Full-text | XML Full-text
Abstract
The safety of high quality drinking water supply relies on the quantities to be delivered, on the complexity of the water supply systems, and on the widespread phenomena of the contamination of water bodies. These parameters indicate the need for the development of
[...] Read more.
The safety of high quality drinking water supply relies on the quantities to be delivered, on the complexity of the water supply systems, and on the widespread phenomena of the contamination of water bodies. These parameters indicate the need for the development of an application that will allow the quick acquisition of data on strategic management. This is requires both the analysis of factors related to the hydraulic operation of the plants and the characteristics of water quality. The present paper aims to evaluate the use of models that predict data for water quality in a distribution system. The assessment is made in order to consider the use of the model as a support tool for the management system of a supply network and to optimize the quality of the provided service. The improvement of the control system related to the operations of disinfection, in particular, in the case of long pipelines, is absolutely mandatory in order to ensure the safety of public health and respect for the environment at high levels. Full article
Figures

Figure 1

Open AccessArticle Hydrologic Regime Changes in a High-Latitude Glacierized Watershed under Future Climate Conditions
Water 2018, 10(2), 128; doi:10.3390/w10020128
Received: 27 October 2017 / Revised: 12 December 2017 / Accepted: 20 December 2017 / Published: 30 January 2018
PDF Full-text (11892 KB) | HTML Full-text | XML Full-text
Abstract
A calibrated conceptual glacio-hydrological monthly water balance model (MWBMglacier) was used to evaluate future changes in water partitioning in a high-latitude glacierized watershed in Southcentral Alaska under future climate conditions. The MWBMglacier was previously calibrated and evaluated against streamflow measurements, literature values of
[...] Read more.
A calibrated conceptual glacio-hydrological monthly water balance model (MWBMglacier) was used to evaluate future changes in water partitioning in a high-latitude glacierized watershed in Southcentral Alaska under future climate conditions. The MWBMglacier was previously calibrated and evaluated against streamflow measurements, literature values of glacier mass balance change, and satellite-based observations of snow covered area, evapotranspiration, and total water storage. Output from five global climate models representing two future climate scenarios (RCP 4.5 and RCP 8.5) was used with the previously calibrated parameters to drive the MWBMglacier at 2 km spatial resolution. Relative to the historical period 1949–2009, precipitation will increase and air temperature in the mountains will be above freezing for an additional two months per year by mid-century which significantly impacts snow/rain partitioning and the generation of meltwater from snow and glaciers. Analysis of the period 1949–2099 reveals that numerous hydrologic regime shifts already occurred or are projected to occur in the study area including glacier accumulation area, snow covered area, and forest vulnerability. By the end of the century, Copper River discharge is projected to increase by 48%, driven by 21% more precipitation and 53% more glacial melt water (RCP 8.5) relative to the historical period (1949–2009). Full article
Figures

Figure 1

Open AccessArticle Identification of Phytoplankton Blooms under the Index of Inherent Optical Properties (IOP Index) in Optically Complex Waters
Water 2018, 10(2), 129; doi:10.3390/w10020129
Received: 23 December 2017 / Revised: 24 January 2018 / Accepted: 26 January 2018 / Published: 30 January 2018
PDF Full-text (2654 KB) | HTML Full-text | XML Full-text
Abstract
Phytoplankton blooms are sporadic events in time and are isolated in space. This complex phenomenon is produced by a variety of both natural and anthropogenic causes. Early detection of this phenomenon, as well as the classification of a water body under conditions of
[...] Read more.
Phytoplankton blooms are sporadic events in time and are isolated in space. This complex phenomenon is produced by a variety of both natural and anthropogenic causes. Early detection of this phenomenon, as well as the classification of a water body under conditions of bloom or non-bloom, remains an unresolved problem. This research proposes the use of Inherent Optical Properties (IOPs) in optically complex waters to detect the bloom or non-bloom state of the phytoplankton community. An IOP index is calculated from the absorption coefficients of the colored dissolved organic matter (CDOM), the phytoplankton ( phy ) and the detritus (d), using the wavelength (λ) 443 nm. The effectiveness of this index is tested in five bloom events in different places and with different characteristics from Mexican seas: 1. Dzilam (Caribbean Sea, Atlantic Ocean), a diatom bloom (Rhizosolenia hebetata); 2. Holbox (Caribbean Sea, Atlantic Ocean), a mixed bloom of dinoflagellates (Scrippsiella sp.) and diatoms (Chaetoceros sp.); 3. Campeche Bay in the Gulf of Mexico (Atlantic Ocean), a bloom of dinoflagellates (Karenia brevis); 4. Upper Gulf of California (UGC) (Pacific Ocean), a diatom bloom (Coscinodiscus and Pseudo-nitzschia) and 5. Todos Santos Bay, Ensenada (Pacific Ocean), a dinoflagellate bloom (Lingulodinium polyedrum). The diversity of sites show that the IOP index is a suitable method to determine the phytoplankton bloom conditions. Full article
Figures

Figure 1

Open AccessArticle Research on Validity Examination of Simulated Results of Eggplant Water Requirements with Drip Irrigation under Mulch in Sunlight Greenhouse
Water 2018, 10(2), 130; doi:10.3390/w10020130
Received: 8 December 2017 / Revised: 18 January 2018 / Accepted: 23 January 2018 / Published: 31 January 2018
PDF Full-text (820 KB) | HTML Full-text | XML Full-text
Abstract
In order to explore the validity of the single and dual crop coefficient approaches in sunlight greenhouses, eggplant with drip irrigation was taken as the study object, and the crop water requirement was calculated via field experiments in a sunlight greenhouse. Results indicated
[...] Read more.
In order to explore the validity of the single and dual crop coefficient approaches in sunlight greenhouses, eggplant with drip irrigation was taken as the study object, and the crop water requirement was calculated via field experiments in a sunlight greenhouse. Results indicated that the results of the two model simulations are satisfactory. Model parameters of the single crop coefficient approach are perfect with a correlation index (R2) of 0.8374, a regression coefficient of 0.8281, an average mean absolute error of 0.2335 mm/day, an average standard error of 0.28 mm/day, a consistency index of relative unbiasedness of 0.9530, and a residual variance of 0.0785. For the dual crop coefficient approach, the model parameters had a correlation index (R2) of 0.8597, a regression coefficient of 0.8220, an average mean absolute error of 0.2196 mm/day, an average standard error of 0.27 mm/day, a consistency index of relative unbiasedness of 0.9543, and a residual variance of 0.0685. The results indicated that the dual crop coefficient model was better than the single crop coefficient model. Our research can provide some reference for the study of crop water requirements with drip irrigation under mulch in a sunlight greenhouse. Full article
Figures

Figure 1

Open AccessArticle Potential of Sentinel-1 Images for Estimating the Soil Roughness over Bare Agricultural Soils
Water 2018, 10(2), 131; doi:10.3390/w10020131
Received: 13 December 2017 / Revised: 24 January 2018 / Accepted: 29 January 2018 / Published: 31 January 2018
PDF Full-text (1752 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this study is to analyze the potential of Sentinel-1 C-band SAR data in VV polarization for estimating the surface roughness (Hrms) over bare agricultural soils. An inversion technique based on Multi-Layer Perceptron neural networks is used. It involves
[...] Read more.
The purpose of this study is to analyze the potential of Sentinel-1 C-band SAR data in VV polarization for estimating the surface roughness (Hrms) over bare agricultural soils. An inversion technique based on Multi-Layer Perceptron neural networks is used. It involves two steps. First, a neural network (NN) is used for estimating the soil moisture without taking into account the soil roughness. Then, a second neural network is used for retrieving the soil roughness when using as an input to the network the soil moisture that was estimated by the first network. The neural networks are trained and validated using simulated datasets generated from the radar backscattering model IEM (Integral Equation Model) with the range of soil moisture and surface roughness encountered in agricultural environments. The inversion approach is then validated using Sentinel-1 images collected over two agricultural study sites, one in France and one in Tunisia. Results show that the use of C-band in VV polarization for estimating the soil roughness does not allow a reliable estimate of the soil roughness. From the synthetic dataset, the achievable accuracy of the Hrms estimates is about 0.94 cm when using the soil moisture estimated by the NN built with a priori information on the moisture volumetric content “mv” (accuracy of mv is about 6 vol. %). In addition, an overestimation of Hrms for low Hrms-values and an underestimation of Hrms for Hrms higher than 2 cm are observed. From a real dataset, results show that the accuracy of the estimates of Hrms in using the mv estimated over a wide area (few km2) is similar to that in using the mv estimated at the plot scale (RMSE about 0.80 cm). Full article
(This article belongs to the Special Issue Applications of Remote Sensing and GIS in Hydrology)
Figures

Figure 1

Open AccessArticle Determining Surface Infiltration Rate of Permeable Pavements with Digital Imaging
Water 2018, 10(2), 133; doi:10.3390/w10020133
Received: 22 December 2017 / Revised: 23 January 2018 / Accepted: 29 January 2018 / Published: 31 January 2018
PDF Full-text (9049 KB) | HTML Full-text | XML Full-text
Abstract
Cell phone images of pervious pavement surfaces were used to explore relationships between surface infiltration rates (SIR) measured using the ASTM C1701 standard test and using a simple falling head test. A fiber-reinforced porous asphalt surface and a highly permeable material comprised of
[...] Read more.
Cell phone images of pervious pavement surfaces were used to explore relationships between surface infiltration rates (SIR) measured using the ASTM C1701 standard test and using a simple falling head test. A fiber-reinforced porous asphalt surface and a highly permeable material comprised of stone, rubber and a polymer binder (Porous Pave) were tested. Images taken with a high-resolution cellphone camera were acquired as JPEG files and converted to gray scale images in Matlab® for analysis. The distribution of gray levels was compared to the surface infiltration rates obtained for both pavements with attention given to the mean of the distribution. Investigation into the relationships between mean SIR and parameters determined from the gray level distribution produced in the image analysis revealed that mean SIR measured in both pavements were proportional to the inverse of the mean of the distribution. The relationships produced a coefficient of determination over 85% using both the ASTM and the falling head test in the porous asphalt surface. SIR measurements determined with the ASTM method were highly correlated with the inverse mean of the distribution of gray levels in the Porous Pave material as well, producing coefficients of determination of over 90% and Kendall’s tau-b of roughly 70% for nonparametric data. Full article
(This article belongs to the Special Issue Permeable Pavements and Their Role in Sustainable Urban Development)
Figures

Figure 1

Open AccessArticle Identifying Critical Elements in Sewer Networks Using Graph-Theory
Water 2018, 10(2), 136; doi:10.3390/w10020136
Received: 4 December 2017 / Revised: 26 January 2018 / Accepted: 27 January 2018 / Published: 31 January 2018
Cited by 1 | PDF Full-text (9375 KB) | HTML Full-text | XML Full-text
Abstract
Underground water infrastructure is essential for life in cities. The aging of these infrastructures requires maintenance strategies to maintain a minimum service level. Not all elements are equally important for the functioning of the infrastructure as a whole. Identifying the most critical elements
[...] Read more.
Underground water infrastructure is essential for life in cities. The aging of these infrastructures requires maintenance strategies to maintain a minimum service level. Not all elements are equally important for the functioning of the infrastructure as a whole. Identifying the most critical elements in a network is crucial for formulating asset management strategies. The graph theory is presented as a means to identify the most critical elements in a network with respect to malfunctioning of the system as a whole. As opposed to conventional methods, the proposed method does not rely on iterative hydraulic calculations; instead, the structure of the network is taken as a starting point. In contrast to methods applied in practise, the results are independent on the chosen test-load. Because of the limited calculation effort, the method allows the analysis of large networks that are now, for practical reasons, beyond the scope of methods applied so-far. Full article
Figures

Figure 1

Open AccessArticle Responses of Water Level in China’s Largest Freshwater Lake to the Meteorological Drought Index (SPEI) in the Past Five Decades
Water 2018, 10(2), 137; doi:10.3390/w10020137
Received: 22 December 2017 / Revised: 20 January 2018 / Accepted: 25 January 2018 / Published: 1 February 2018
PDF Full-text (19797 KB) | HTML Full-text | XML Full-text
Abstract
Poyang Lake, which is the largest freshwater lake in China, is an important regional water resource and iconic ecosystem that has experienced a period of continuous low water level in recent years. In this paper, the Standardized Precipitation Evapotranspiration Index (SPEI) was applied
[...] Read more.
Poyang Lake, which is the largest freshwater lake in China, is an important regional water resource and iconic ecosystem that has experienced a period of continuous low water level in recent years. In this paper, the Standardized Precipitation Evapotranspiration Index (SPEI) was applied to analyze the temporal variability and spatial distribution characteristics of meteorological drought over the Poyang Lake Basin during 1961–2015. In addition, correlation analysis was used to investigate the response relationship between lake level and meteorological drought in the basin. The main results showed that: (1) The decline of water level in Poyang Lake since 2000 has been dramatic, especially in autumn, when the downward speed reached 11.26 cm/day. (2) The meteorological drought in the Poyang Lake Basin has obvious seasonal characteristics, and drying tendencies in spring and autumn were relatively obvious. Following the 1960s, this basin entered a new drought period in the 2000s. (3) The results of correlation analysis showed that three- and six-month timescales were the optimum times for the lake level to respond to the SPEI in the Poyang Lake Basin. Seasonally, the correlation was best in winter and worst in autumn. Furthermore, the spatial distribution of correlations was: Hukou < Xingzi < Duchang < Wucheng < Tangyin < Kangshan. Overall, the results of this study quantified the response of lake level to meteorological drought in the context of climate change, and they provide a reliable scientific basis for water resource management in similar basins. Full article
Figures

Figure 1

Open AccessArticle Empirical Characterization of Particle Size Distribution Spatial Dynamics for Helminth Eggs Detection in Waste Stabilization Ponds (WSP)
Water 2018, 10(2), 138; doi:10.3390/w10020138
Received: 13 December 2017 / Revised: 12 January 2018 / Accepted: 24 January 2018 / Published: 1 February 2018
PDF Full-text (1895 KB) | HTML Full-text | XML Full-text
Abstract
This study assesses seasonal particle size distribution (PSD) dynamics inside a waste stabilization ponds (WSP) (Buguruni, Tanzania) to understand settling dynamics of wastewater particles with an interest in helminth eggs. Results indicate that particles coming into the pond are mainly supracolloidal and settleables
[...] Read more.
This study assesses seasonal particle size distribution (PSD) dynamics inside a waste stabilization ponds (WSP) (Buguruni, Tanzania) to understand settling dynamics of wastewater particles with an interest in helminth eggs. Results indicate that particles coming into the pond are mainly supracolloidal and settleables with 52.9% and 45.6%, respectively, in dry season and 48.9% and 49.9%, respectively, in wet season. Inflow PSD is a unimodal distribution that splits into settling and suspended PSDs, with an indication of particle breakage, as shown by the increased volume of smaller particles and hence the appearance of a bimodal distribution for the suspended particles. Up to 61.5% and 45.2% of particles that fall within the size range of helminths eggs are suspended during dry and wet seasons, respectively, with the potential to be carried in the effluent and to cause contamination. Full article
Figures

Figure 1

Open AccessArticle Multi-Stakeholder Development of a Serious Game to Explore the Water-Energy-Food-Land-Climate Nexus: The SIM4NEXUS Approach
Water 2018, 10(2), 139; doi:10.3390/w10020139
Received: 15 December 2017 / Revised: 19 January 2018 / Accepted: 30 January 2018 / Published: 1 February 2018
PDF Full-text (6395 KB) | HTML Full-text | XML Full-text
Abstract
Water, energy, food, land and climate form a tightly-connected nexus in which actions on one sector impact other sectors, creating feedbacks and unanticipated consequences. This is especially because at present, much scientific research and many policies are constrained to single discipline/sector silos that
[...] Read more.
Water, energy, food, land and climate form a tightly-connected nexus in which actions on one sector impact other sectors, creating feedbacks and unanticipated consequences. This is especially because at present, much scientific research and many policies are constrained to single discipline/sector silos that are often not interacting (e.g., water-related research/policy). However, experimenting with the interaction and determining how a change in one sector could impact another may require unreasonable time frames, be very difficult in practice and may be potentially dangerous, triggering any one of a number of unanticipated side-effects. Current modelling often neglects knowledge from practice. Therefore, a safe environment is required to test the potential cross-sectoral implications of policy decisions in one sector on other sectors. Serious games offer such an environment by creating realistic ‘simulations’, where long-term impacts of policies may be tested and rated. This paper describes how the ongoing (2016–2020) Horizon2020 project SIM4NEXUS will develop serious games investigating potential plausible cross-nexus implications and synergies due to policy interventions for 12 multi-scale case studies ranging from regional to global. What sets these games apart is that stakeholders and partners are involved in all aspects of the modelling definition and process, from case study conceptualisation, quantitative model development including the implementation and validation of each serious game. Learning from playing a serious game is justified by adopting a proof-of-concept for a specific regional case study in Sardinia (Italy). The value of multi-stakeholder involvement is demonstrated, and critical lessons learned for serious game development in general are presented. Full article
Figures

Figure 1

Open AccessArticle The Total Risk Analysis of Large Dams under Flood Hazards
Water 2018, 10(2), 140; doi:10.3390/w10020140
Received: 3 December 2017 / Revised: 20 January 2018 / Accepted: 24 January 2018 / Published: 1 February 2018
PDF Full-text (1433 KB) | HTML Full-text | XML Full-text
Abstract
Dams and reservoirs are useful systems in water conservancy projects; however, they also pose a high-risk potential for large downstream areas. Flood, as the driving force of dam overtopping, is the main cause of dam failure. Dam floods and their risks are of
[...] Read more.
Dams and reservoirs are useful systems in water conservancy projects; however, they also pose a high-risk potential for large downstream areas. Flood, as the driving force of dam overtopping, is the main cause of dam failure. Dam floods and their risks are of interest to researchers and managers. In hydraulic engineering, there is a growing tendency to evaluate dam flood risk based on statistical and probabilistic methods that are unsuitable for the situations with rare historical data or low flood probability, so a more reasonable dam flood risk analysis method with fewer application restrictions is needed. Therefore, different from previous studies, this study develops a flood risk analysis method for large dams based on the concept of total risk factor (TRF) used initially in dam seismic risk analysis. The proposed method is not affected by the adequacy of historical data or the low probability of flood and is capable of analyzing the dam structure influence, the flood vulnerability of the dam site, and downstream risk as well as estimating the TRF of each dam and assigning corresponding risk classes to each dam. Application to large dams in the Dadu River Basin, Southwestern China, demonstrates that the proposed method provides quick risk estimation and comparison, which can help local management officials perform more detailed dam safety evaluations for useful risk management information. Full article
Figures

Figure 1

Open AccessArticle Well Salinization Risk and Effects of Baltic Sea Level Rise on the Groundwater-Dependent Island of Öland, Sweden
Water 2018, 10(2), 141; doi:10.3390/w10020141
Received: 16 December 2017 / Revised: 22 January 2018 / Accepted: 25 January 2018 / Published: 1 February 2018
PDF Full-text (4800 KB) | HTML Full-text | XML Full-text
Abstract
In this study, we estimate baseline conditions in terms of the current risk of well salinization on the Baltic Sea island of Öland, Sweden, and assess the effects of future sea level rise on the land area, infrastructure and cultural values. We use
[...] Read more.
In this study, we estimate baseline conditions in terms of the current risk of well salinization on the Baltic Sea island of Öland, Sweden, and assess the effects of future sea level rise on the land area, infrastructure and cultural values. We use a multicriterion geographical information systems (GIS) approach. Geomorphological and physical parameters affect the risk of saltwater intrusion into freshwater aquifers, including their hydrology, geomorphology, and climatology; the spatial distribution of the current risk of salinization is mapped in this study. In the event of a future 2 m sea level rise, a total land area of 67 km2 will be inundated on Öland, corresponding to approximately 5% of the island’s land surface. Inundation includes urban areas, nature reserves, and animal protection areas, implying the loss of environmental and socioeconomic values. A future 2 m sea level rise will also cause direct inundation of 3% of all wells on the island. Currently, 17.5% of all wells are at a high risk of becoming saltwater contaminated. More generally, the present results add evidence showing a relatively high vulnerability of major Baltic Sea islands and their infrastructure to future sea level rise. The approach used here and related results, including salinization risk maps, may prove useful for decision-makers in the planning of infrastructure. Drilling of new wells could for instance preferably be done in areas with identified lower risk-index values, which would facilitate an overall higher freshwater withdrawal in the interest of the entire island. Full article
(This article belongs to the Special Issue Seawater Intrusion: Simulation and Control)
Figures

Figure 1

Open AccessArticle Gene Expression Programming Coupled with Unsupervised Learning: A Two-Stage Learning Process in Multi-Scale, Short-Term Water Demand Forecasts
Water 2018, 10(2), 142; doi:10.3390/w10020142
Received: 21 November 2017 / Revised: 25 January 2018 / Accepted: 30 January 2018 / Published: 2 February 2018
PDF Full-text (1645 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This article proposes a new general approach in short-term water demand forecasting based on a two-stage learning process that couples time-series clustering with gene expression programming (GEP). The approach was tested on the real life water demand data of the city
[...] Read more.
This article proposes a new general approach in short-term water demand forecasting based on a two-stage learning process that couples time-series clustering with gene expression programming (GEP). The approach was tested on the real life water demand data of the city of Milan, in Italy. Moreover, multi-scale modeling using a series of head-time was deployed to investigate the optimum temporal resolution under study. Multi-scale modeling was performed based on rearranging hourly based patterns of water demand into 3, 6, 12, and 24 h lead times. Results showed that GEP should receive more attention among the emerging nonlinear modelling techniques if coupled with unsupervised learning algorithms in detailed spherical k-means. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Groundwater Overexploitation and Seawater Intrusion in Coastal Areas of Arid and Semi-Arid Regions
Water 2018, 10(2), 143; doi:10.3390/w10020143
Received: 19 December 2017 / Revised: 24 January 2018 / Accepted: 25 January 2018 / Published: 2 February 2018
PDF Full-text (7422 KB) | HTML Full-text | XML Full-text
Abstract
The exploitation of groundwater resources is of high importance and has become very crucial in the last decades, especially in coastal areas of arid and semi-arid regions. The coastal aquifers in these regions are particularly at risk due to intrusion of salty marine
[...] Read more.
The exploitation of groundwater resources is of high importance and has become very crucial in the last decades, especially in coastal areas of arid and semi-arid regions. The coastal aquifers in these regions are particularly at risk due to intrusion of salty marine water. One example is the case of Tripoli city at the Mediterranean coast of Jifarah Plain, North West Libya. Libya has experienced progressive seawater intrusion in the coastal aquifers since the 1930s because of its ever increasing water demand from underground water resources. Tripoli city is a typical area where the contamination of the aquifer in the form of saltwater intrusion is very developed. Sixty-four groundwater samples were collected from the study area and analyzed for certain parameters that indicate salinization and pollution of the aquifer. The results demonstrate high values of the parameters Electrical Conductivity, Na+, K+, Mg2+, Cl and SO42−, which can be attributed to seawater intrusion, where Cl is the major pollutant of the aquifer. The water types according to the Stuyfzand groundwater classification are mostly CaCl, NaCl and Ca/MgMix. These water types indicate that groundwater chemistry is changed by cation exchange reactions during the mixing process between freshwater and seawater. The intensive extraction of groundwater from the aquifer reduces freshwater outflow to the sea, creates drawdown cones and lowering of the water table to as much as 25 m below mean sea level. Irrigation with nitrogen fertilizers and domestic sewage and movement of contaminants in areas of high hydraulic gradients within the drawdown cones probably are responsible for the high NO3 concentration in the region. Full article
Figures

Figure 1

Open AccessArticle Quantifying Climatic Impact on Reference Evapotranspiration Trends in the Huai River Basin of Eastern China
Water 2018, 10(2), 144; doi:10.3390/w10020144
Received: 18 December 2017 / Revised: 23 January 2018 / Accepted: 30 January 2018 / Published: 2 February 2018
Cited by 2 | PDF Full-text (20811 KB) | HTML Full-text | XML Full-text
Abstract
Reference evapotranspiration (ETref) is an important study object for hydrological cycle processes in the context of drought-flood risks of the Huai River Basin (HRB). In this study, the FAO-56 Penman–Monteith (PM) model was employed to calculate seasonal and annual ET
[...] Read more.
Reference evapotranspiration (ETref) is an important study object for hydrological cycle processes in the context of drought-flood risks of the Huai River Basin (HRB). In this study, the FAO-56 Penman–Monteith (PM) model was employed to calculate seasonal and annual ETref based on 137 meteorological station data points in HRB from 1961 to 2014. The Mann–Kendall (MK) trend analysis was adopted together with Theil–Sen’s estimator to detect tendencies of ETref and climate factors. Furthermore, a developed differential equation method based on the FAO-56 PM model was applied to quantify the sensitivities of ETref to meteorological factors and their contributions to ETref trends. The results showed that the ETref demonstrated a strong spatially heterogeneity in the whole HRB at each time scale. ETref showed a significant decreasing trend in the upper-middle HRB and Yi-Shu-Si River Basin, especially at the annual time scale, in growing season and summer, while a generally increasing trend in ETref was detected in the lower HRB, and the significance only showed in spring. These phenomena could be reasonably explained by a significantly increasing mean temperature (TA), a significantly decreasing wind speed (WS), solar radiation (SR), and a slightly decreasing relative humidity (RH). The most sensitive factor to ETref was RH in most sub-regions and most time scales, except in the growing season and summer. Based on the developed differential equation method, the dominant factor of the decreasing ETref was WS in the annual time scale, spring, autumn, and winter in most sub-regions, except the lower HRB, which then shifted to SR in the growing season and summer. However, in the lower HRB, the significantly decreasing RH was the most dominant factor, especially in the annual time scale, growing season, and spring, which might be responsible for the slightly increasing ETref there. Full article
Figures

Figure 1

Open AccessArticle Improving Stochastic Modelling of Daily Rainfall Using the ENSO Index: Model Development and Application in Chile
Water 2018, 10(2), 145; doi:10.3390/w10020145
Received: 21 December 2017 / Revised: 18 January 2018 / Accepted: 30 January 2018 / Published: 2 February 2018
PDF Full-text (4436 KB) | HTML Full-text | XML Full-text
Abstract
Stochastic weather simulation, or weather generators (WGs), have gained a wide acceptance and been used for a variety of purposes, including climate change studies and the evaluation of climate variability and uncertainty effects. The two major challenges in WGs are improving the estimation
[...] Read more.
Stochastic weather simulation, or weather generators (WGs), have gained a wide acceptance and been used for a variety of purposes, including climate change studies and the evaluation of climate variability and uncertainty effects. The two major challenges in WGs are improving the estimation of interannual variability and reducing overdispersion in the synthetic series of simulated weather. The objective of this work is to develop a WG model of daily rainfall, incorporating a covariable that accounts for interannual variability, and apply it in three climate regions (arid, Mediterranean, and temperate) of Chile. Precipitation occurrence was modeled using a two-stage, first-order Markov chain, whose parameters are fitted with a generalized lineal model (GLM) using a logistic function. This function considers monthly values of the observed Sea Surface Temperature Anomalies of the Region 3.4 of El Niño-Southern Oscillation (ENSO index) as a covariable. Precipitation intensity was simulated with a mixed exponential distribution, fitted using a maximum likelihood approach. The stochastic simulation shows that the application of the approach to Mediterranean and arid climates largely eliminates the overdispersion problem, resulting in a much improved interannual variability in the simulated values. Full article
Figures

Figure 1

Open AccessArticle Decision Support System for the Design and Planning of Low-Impact Development Practices: The Case of Seoul
Water 2018, 10(2), 146; doi:10.3390/w10020146
Received: 3 December 2017 / Revised: 18 January 2018 / Accepted: 30 January 2018 / Published: 2 February 2018
PDF Full-text (1614 KB) | HTML Full-text | XML Full-text
Abstract
This study presented the conceptual framework of the water-management analysis module (WMAM) to derive effective physical specifications for the design and planning of low-impact development (LID) practices using the storm-water management model (SWMM). This decision-support system can be used for six LID types
[...] Read more.
This study presented the conceptual framework of the water-management analysis module (WMAM) to derive effective physical specifications for the design and planning of low-impact development (LID) practices using the storm-water management model (SWMM). This decision-support system can be used for six LID types and has the following key capabilities: determining relevant LID design parameters within the SWMM that critically influence the hydrological cycle components using a simple sensitivity analysis and determining the best hydrological values for LID planning specification. This study analyzed a highly urbanized university campus as a case study to determine the design and planning specifications for an infiltration trench and permeable pavement. In addition, the performance of different LID practices during high-intensity rainfall events was compared. The results indicate that the WMAM can be very useful in determining many LID design and planning parameters. Full article
Figures

Figure 1

Open AccessFeature PaperArticle Improving the Multi-Objective Performance of Rainwater Harvesting Systems Using Real-Time Control Technology
Water 2018, 10(2), 147; doi:10.3390/w10020147
Received: 21 November 2017 / Revised: 20 January 2018 / Accepted: 30 January 2018 / Published: 2 February 2018
PDF Full-text (2139 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Many studies have identified the potential of rainwater harvesting (RWH) systems to simultaneously augment potable water supply and reduce delivery of uncontrolled stormwater flows to downstream drainage networks. Potentially, such systems could also play a role in the controlled delivery of water to
[...] Read more.
Many studies have identified the potential of rainwater harvesting (RWH) systems to simultaneously augment potable water supply and reduce delivery of uncontrolled stormwater flows to downstream drainage networks. Potentially, such systems could also play a role in the controlled delivery of water to urban streams in ways which mimic baseflows. The performance of RWH systems to achieve these three objectives could be enhanced using Real-Time Control (RTC) technology to receive rainfall forecasts and initiate pre-storm release in real time, although few studies have explored such potential. We used continuous simulation to model the ability of a range of allotment-scale RWH systems to simultaneously deliver: (i) water supply; (ii) stormwater retention; and (iii) baseflow restoration. We compared the performance of RWH systems with RTC technology to conventional RWH systems and also systems designed with a passive baseflow release, rather than the active (RTC) configuration. We found that RWH systems employing RTC technology were generally superior in simultaneously achieving water supply, stormwater retention and baseflow restoration benefits compared with the other types of system tested. The active operation provided by RTC allows the system to perform optimally across a wider range of climatic conditions, but needs to be carefully designed. We conclude that the active release mechanism employing RTC technology exhibits great promise; its ability to provide centralised control and failure detection also opens the possibility of delivering a more reliable rainwater harvesting system, which can be readily adapted to varying climate over both the short and long term. Full article
(This article belongs to the Special Issue Development of Alternative Water Sources in the Urban Sector)
Figures

Figure 1

Open AccessArticle A First Estimation of County-Based Green Water Availability and Its Implications for Agriculture and Bioenergy Production in the United States
by and
Water 2018, 10(2), 148; doi:10.3390/w10020148
Received: 21 November 2017 / Revised: 20 January 2018 / Accepted: 25 January 2018 / Published: 2 February 2018
PDF Full-text (27206 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Green water is vital for the terrestrial ecosystem, but water resource assessment often focuses on blue water. In this study, we estimated green water availability for major crops (i.e., corn, soybean, and wheat) and all other users (e.g., forest, grassland, and ecosystem services)
[...] Read more.
Green water is vital for the terrestrial ecosystem, but water resource assessment often focuses on blue water. In this study, we estimated green water availability for major crops (i.e., corn, soybean, and wheat) and all other users (e.g., forest, grassland, and ecosystem services) at the county level in the United States. We estimated green water resources from effective rain (ER) using three different methods: Smith, U.S. Department of Agriculture—Soil Conservation Service (USDA-SCS), and the NHD plus V2 dataset. The analysis illustrates that, if green water meets all crop water demands, the fraction of green water resources available to all other users varies significantly across regions, from the Northern Plains (0.71) to the Southeast (0.98). At the county level, this fraction varies from 0.23 to 1.0. Green water resources estimated using the three different ER methods present diverse spatiotemporal distribution patterns across regions, which could affect green water availability estimates. The water availability index for green water (WAI_R) was measured taking into account crop water demand and green water resources aggregated at the county level. Beyond these parameters, WAI_R also depends on the precipitation pattern, crop type and spatially differentiated regions. In addition, seasonal analysis indicated that WAI_R is sensitive to the temporal boundary of the analysis. Full article
(This article belongs to the Special Issue Progress in Water Footprint Assessment)
Figures

Figure 1

Open AccessArticle Land Use Change over the Amazon Forest and Its Impact on the Local Climate
Water 2018, 10(2), 149; doi:10.3390/w10020149
Received: 7 November 2017 / Revised: 19 January 2018 / Accepted: 22 January 2018 / Published: 3 February 2018
PDF Full-text (1998 KB) | HTML Full-text | XML Full-text
Abstract
One of the most important anthropogenic influences on climate is land use change (LUC). In particular, the Amazon (AMZ) basin is a highly vulnerable area to climate change due to substantial modifications of the hydroclimatology of the region expected as a result of
[...] Read more.
One of the most important anthropogenic influences on climate is land use change (LUC). In particular, the Amazon (AMZ) basin is a highly vulnerable area to climate change due to substantial modifications of the hydroclimatology of the region expected as a result of LUC. However, both the magnitude of these changes and the physical process underlying this scenario are still uncertain. This work aims to analyze the simulated Amazon deforestation and its impacts on local mean climate. We used the Common Land Model (CLM) version 4.5 coupled with the Regional Climate Model (RegCM4) over the Coordinated Regional Climate Downscaling Experiment (CORDEX) South America domain. We performed one simulation with the RegCM4 default land cover map (CTRL) and one simulation under a scenario of deforestation (LUC), i.e., replacing broadleaf evergreen trees with C3 grass over the Amazon basin. Both simulations were driven by ERA Interim reanalysis from 1979 to 2009. The climate change signal due to AMZ deforestation was evaluated by comparing the climatology of CTRL with LUC. Concerning the temperature, the deforested areas are about 2 °C warmer compared to the CTRL experiment, which contributes to decrease the surface pressure. Higher air temperature is associated with a decrease of the latent heat flux and an increase of the sensible heat flux over the deforested areas. AMZ deforestation induces a dipole pattern response in the precipitation over the region: a reduction over the west (about 7.9%) and an increase over the east (about 8.3%). Analyzing the water balance in the atmospheric column over the AMZ basin, the results show that under the deforestation scenario the land surface processes play an important role and drive the precipitation in the western AMZ; on the other hand, on the east side, the large scale circulation drives the precipitation change signal. Dipole patterns over scenarios of deforestation in the Amazon was also found by other authors, but the precipitation decrease on the west side was never fully explained. Using budget equations, this work highlights the physical processes that control the climate in the Amazon basin under a deforestation scenario. Full article
Figures

Figure 1

Open AccessArticle Application of a Low Cost Ceramic Filter for Recycling Sand Filter Backwash Water
Water 2018, 10(2), 150; doi:10.3390/w10020150
Received: 17 December 2017 / Revised: 26 January 2018 / Accepted: 30 January 2018 / Published: 3 February 2018
PDF Full-text (3216 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study is to examine the application of a low cost ceramic filter for the treatment of sand filter backwash water (SFBW). The treatment process is comprised of pre-coagulation of SFBW with aluminum sulfate (Alum) followed by continuous filtration usinga
[...] Read more.
The aim of this study is to examine the application of a low cost ceramic filter for the treatment of sand filter backwash water (SFBW). The treatment process is comprised of pre-coagulation of SFBW with aluminum sulfate (Alum) followed by continuous filtration usinga low cost ceramic filter at different trans-membrane pressures (TMPs). Jar test results showed that 20 mg/L of alum is the optimum dose for maximum removal of turbidity, Fe, and Mn from SFBW. The filter can be operated at a TMP between 0.6 and 3 kPa as well as a corresponding flux of 480–2000 L/m2/d without any flux declination. Significant removal, up to 99%, was observed forturbidity, iron (Fe), and manganese (Mn). The flux started to decline at 4.5 kPa TMP (corresponding flux 3280 L/m2/d), thus indicated fouling of the filter. The complete pore blocking model was found as the most appropriate model to explain the insight mechanism of flux decline. The optimum operating pressure and the permeate flux were found to be 3 kPa and 2000 L/m2/d, respectively. Treated SFBW by a low cost ceramic filter was found to be suitable to recycle back to the water treatment plant. The ceramic filtration process would be a low cost and efficient option to recycle the SFBW. Full article
Figures

Figure 1

Open AccessArticle Environmental Variability and Macrophyte Assemblages in Coastal Lagoon Types of Western Greece (Mediterranean Sea)
Water 2018, 10(2), 151; doi:10.3390/w10020151
Received: 21 December 2017 / Revised: 26 January 2018 / Accepted: 30 January 2018 / Published: 3 February 2018
PDF Full-text (7933 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Coastal lagoon types of Western Greece were allocated to a spectrum of meso to polyhaline chocked lagoons; poly to euhaline restricted lagoons; and euhaline restricted lagoons along the Ionian Sea coast. This diversity comprises wide ranges of physical, chemical and environmental parameters in
[...] Read more.
Coastal lagoon types of Western Greece were allocated to a spectrum of meso to polyhaline chocked lagoons; poly to euhaline restricted lagoons; and euhaline restricted lagoons along the Ionian Sea coast. This diversity comprises wide ranges of physical, chemical and environmental parameters in a seasonal and annual scale, which explains the variability in the distribution of benthic macrophytes. Four different macrophyte assemblages were distinguished, characterized by annual or perennial species. Extensive statistical analysis showed that salinity and nitrate concentrations had a great impact on the composition and distribution of macrophyte assemblages into lagoon types that also changed their abundance on a seasonal and annual scale. During the monitoring period, an important salinity shift in a chocked lagoon might cause the gradual loss of Zostera noltii and its replacement by Ruppia cirrhosa. Restricted lagoons were characterized by higher species diversity, while the other three identified macrophyte assemblages were dominated by the angiosperms Ruppia cirrhosa and Cymodocea nodosa. This integrated study of coastal lagoons is likely to be broadly applicable, since it was based on important parameters affecting such ecosystems, and the provided links between macrophyte assemblages and abiotic factors are of critical importance to improve management and environmental policies. Full article
Figures

Figure 1

Open AccessArticle Impacts of Environmental Variables on a Phytoplankton Community: A Case Study of the Tributaries of a Subtropical River, Southern China
Water 2018, 10(2), 152; doi:10.3390/w10020152
Received: 15 December 2017 / Revised: 2 February 2018 / Accepted: 2 February 2018 / Published: 4 February 2018
PDF Full-text (2124 KB) | HTML Full-text | XML Full-text
Abstract
The phytoplankton community in the river is closely related to the location of the river and the impact of human activities. To summarize the patterns of phytoplankton community changes in rivers and to analyze the reasons for these patterns and differences, we sampled
[...] Read more.
The phytoplankton community in the river is closely related to the location of the river and the impact of human activities. To summarize the patterns of phytoplankton community changes in rivers and to analyze the reasons for these patterns and differences, we sampled the three tributaries of the Dongjiang River at different latitudes in the dry and rainy season for three years. The results showed that the three rivers were mesotrophic, lightly eutrophic and moderately eutrophic respectively. From the south to the north, the water temperature and nutrition showed an increasing trend. In two different seasons, the differences in the water temperature and dissolved oxygen were clear. In the dry season, results of the multidimensional scaling (MDS) analysis indicated that the phytoplankton community structures in the Li River and Qiuxiang River were similar. Regardless of the number of species, the cell abundance or the dominance index, Bacillariophyta were found to be dominant. Chlorophyta was dominant in the Danshui River. In the rainy season, Bacillariophyta, Bacillariophyta-Chlorophyta and Chlorophyta-Cyanophyta became the dominant types in the Li River, Qiuxiang River and Danshui River, respectively. These different patterns in phytoplankton community variation were affected by both the water quality and temperature. Full article
Figures

Figure 1

Open AccessArticle Global Sensitivity Analysis of a Water Quality Model in the Three Gorges Reservoir
Water 2018, 10(2), 153; doi:10.3390/w10020153
Received: 6 December 2017 / Revised: 29 January 2018 / Accepted: 31 January 2018 / Published: 5 February 2018
PDF Full-text (796 KB) | HTML Full-text | XML Full-text
Abstract
Global sensitivity analysis is the key to establishing advanced and complex water quality models and measurements of ecological parameters. In this paper, the Sobol’s sensitivity analysis method was applied to a quantitative analysis of the important factors governing a water quality model, which
[...] Read more.
Global sensitivity analysis is the key to establishing advanced and complex water quality models and measurements of ecological parameters. In this paper, the Sobol’s sensitivity analysis method was applied to a quantitative analysis of the important factors governing a water quality model, which has been developed to simulate algal dynamics in Caotang Bay, one of the tributary bays in the Three Gorges Reservoir, China. The analysis focused on the response of chlorophyll-a and dissolved oxygen to 11 parameters. The results show that chlorophyll-a is influenced mainly by the maximum phytoplankton growth rate, the lower optimum temperature for algal growth, the phosphate half-saturation constant, and the phytoplankton linear mortality rate; while dissolved oxygen is influenced mainly by the maximum phytoplankton growth rate, the lower optimum temperature for algal growth, the phytoplankton basal respiration rate, and the detritus remineralization rate. These parameter sensitivities change with time and have a marked seasonal pattern. The parameter sensitivity differences between a shallow lake or reservoir and a deep reservoir suggest that mechanisms of cycling in nutrients and dissolved oxygen are different. Full article
Figures

Figure 1

Open AccessArticle The Effects of Antibiotics on Microbial Community Composition in an Estuary Reservoir during Spring and Summer Seasons
Water 2018, 10(2), 154; doi:10.3390/w10020154
Received: 23 November 2017 / Revised: 24 December 2017 / Accepted: 17 January 2018 / Published: 6 February 2018
PDF Full-text (4085 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The increased antibiotic pollutants in aquatic environments pose severe threats on microbial ecology due to their extensive distribution and antibacterial properties. A total of 16 antibiotics including fluoroquinolones (FQs) (ofloxacin (OFX), ciprofloxacin (CFX), norfloxacin (NFX)), Sulfonamides (SAs) (sulfamonomethoxine (SMM), sulfadiazine (SDZ), sulfaquinoxaline (SQX)),
[...] Read more.
The increased antibiotic pollutants in aquatic environments pose severe threats on microbial ecology due to their extensive distribution and antibacterial properties. A total of 16 antibiotics including fluoroquinolones (FQs) (ofloxacin (OFX), ciprofloxacin (CFX), norfloxacin (NFX)), Sulfonamides (SAs) (sulfamonomethoxine (SMM), sulfadiazine (SDZ), sulfaquinoxaline (SQX)), Tetracyclines (TCs) (tetracycline (TC), doxycycline (DC)), β-lactams (penicillin G (PEN G), penicillin V (PEN V), cefalexin (LEX)), Macrolides (MLs) (erythromycin-H2O (ETM), tylosin (TYL)) and other antibiotics (Polymix-B (POL), Vancomycin (VAN), Lincomycin (LIN)) were detected in the surface water of the Qingcaosha Reservoir. Multivariate statistical analysis indicated that both water quality and physicochemical indexes have less contributions on variations of these antibiotics, suggesting the concentrations of antibiotics inside the reservoir are mainly affected by upstream runoff and anthropic activity along the river. Antibiotics including TYL, PEN G and ETM showed significant correlations with variations of bacterial community composition, and closely connected with various gram-negative bacteria in co-occurrence/exclusion patterns of the network, suggesting these bacterial taxa play important roles in the course of migration and transformation of related antibiotics. In conclusion, further research is required to evaluate the potential risk of genetic transfer of resistance to related bacteria induced by long-term exposure to low levels of antibiotics in the environment. Full article
(This article belongs to the Special Issue Antimicrobial Resistance in Environmental Waters)
Figures

Figure 1a

Open AccessArticle Treatment of Dairy Wastewater by Oxygen Injection: Occurrence and Removal Efficiency of a Benzotriazole Based Anticorrosive
Water 2018, 10(2), 155; doi:10.3390/w10020155
Received: 12 December 2017 / Revised: 23 January 2018 / Accepted: 30 January 2018 / Published: 6 February 2018
PDF Full-text (1134 KB) | HTML Full-text | XML Full-text
Abstract
Benzotriazole is used as corrosion inhibitor in many industrial sectors, such as the dairy industry. Due to its widespread use in various applications and everyday consumer products, this chemical easily reaches the aquatic environment, where it may have deleterious effects. In fact, benzotriazole
[...] Read more.
Benzotriazole is used as corrosion inhibitor in many industrial sectors, such as the dairy industry. Due to its widespread use in various applications and everyday consumer products, this chemical easily reaches the aquatic environment, where it may have deleterious effects. In fact, benzotriazole has been included among the so-called emerging contaminants. In this work, the occurrence and fate of a benzotriazole based anticorrosive (BTA-A) during wastewater treatment in a dairy industry has been assessed. At this dairy, a new system for wastewater treatment based on the injection of pure oxygen was recently started. This system has been proved to be efficient, economic and able to stably operate under a wide range of chemical oxygen demand and total suspended solids inputs. Then, after detecting the presence of BTA-A in the effluent of the wastewater treatment plant, it was aimed to optimize oxygen injection for the removal of this anticorrosive together with the regulated parameters. The performance of the system was evaluated at a real scale during a month period, during which the mean removal performance of the oxygen injection based treatment was 91%, 90% and 99% for chemical oxygen demand, total suspended solids and BTA-A, respectively. Full article
(This article belongs to the Special Issue Recent Advances in Water Management: Saving, Treatment and Reuse)
Figures

Figure 1

Open AccessArticle French Reed Bed as a Solution to Minimize the Operational and Maintenance Costs of Wastewater Treatment from a Small Settlement: An Italian Example
Water 2018, 10(2), 156; doi:10.3390/w10020156
Received: 29 December 2017 / Revised: 29 January 2018 / Accepted: 2 February 2018 / Published: 6 February 2018
PDF Full-text (1601 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
French Reed Bed (FRB) is a particular constructed wetland (CW) solution which receives raw wastewater. Data from the full-scale FRB wastewater treatment plant of Castelluccio di Norcia (center of Italy) were collected to show the FRB capability to minimize the operational and management
[...] Read more.
French Reed Bed (FRB) is a particular constructed wetland (CW) solution which receives raw wastewater. Data from the full-scale FRB wastewater treatment plant of Castelluccio di Norcia (center of Italy) were collected to show the FRB capability to minimize the operational and management (O&M) costs. The system was designed to treat wastewater variable from 200 person equivalent (PE) in off-season up to 1000 PE. Data from 2014 up to 2016 showed high removal efficiency in line with French experiences with FRBs. An interview was conducted with the Water Utility to estimate the operational and maintenance (O&M) costs faced by the WWTP, which allowed us to detail the O&M costs for energy consumption, water quality samples, and personnel for inspection. Other O&M expenditure items were estimated on the basis of parametric costs from the executive design. The FRB O&M costs in euro for 500–1000 PE (6–11 € PE−1 year−1) resulted from 5 to 13 lower in comparison to those reported for classical activated sludge systems in an Italian context (45–90 € year−1). The low O&M costs are mainly due to the limited energy consumed and to the minimized costs of sludge management. Full article
(This article belongs to the Special Issue Advances in the Economic Analysis of Residential Water Use)
Figures

Open AccessArticle Impacts of Climate Change and Land Subsidence on Inundation Risk
Water 2018, 10(2), 157; doi:10.3390/w10020157
Received: 12 December 2017 / Revised: 15 January 2018 / Accepted: 1 February 2018 / Published: 6 February 2018
PDF Full-text (11302 KB) | HTML Full-text | XML Full-text
Abstract
In this study, a physiographic drainage-inundation model was used to analyse the impacts of land subsidence and climate change on inundation disaster and risk in a land subsidence area. The results indicated that for land subsidence and land subsidence combined with climate change,
[...] Read more.
In this study, a physiographic drainage-inundation model was used to analyse the impacts of land subsidence and climate change on inundation disaster and risk in a land subsidence area. The results indicated that for land subsidence and land subsidence combined with climate change, inundation area, and volume increased under one- and two-day storms for 2-, 5-, 10-, 25-, 50-, 100-, and 200-year return periods. Moreover, locations that originally had high inundation depth showed even greater inundated areas and volumes in the presence of land subsidence. The inundation phenomenon under the combination of land subsidence and climate change proved to be severe, compared to that of land subsidence alone. Land subsidence increased not only inundation depth but also inundation duration. Given land subsidence and climate change, the average inundation duration for each return period increased. The average flooding duration for each return period post land subsidence was found to be 1.05–1.1 times greater than that preceding it. Under the combination of land subsidence and climate change, the average flooding duration for each return period post land subsidence was about 1.13–1.27 times greater than that before it. Furthermore, by assessing inundation risk with inundation depth index, inundation duration index, and damage index from different land uses, it was found that after land subsidence, inundation risk showed an increase, which was amplified in the presence of land subsidence combined with climate change. Full article
Figures

Figure 1

Open AccessArticle Impact of a Programme for Water Affordability on Residential Consumption: Implementation of the “Programa Mínimo Vital de Agua Potable” in Bogotá, Colombia
Water 2018, 10(2), 158; doi:10.3390/w10020158
Received: 3 December 2017 / Revised: 25 January 2018 / Accepted: 2 February 2018 / Published: 6 February 2018
PDF Full-text (1502 KB) | HTML Full-text | XML Full-text
Abstract
Affordability of services is a determinant for people’s level of access to water. In this study, we analyse the effect of a programme aimed at improving the affordability of water services on users’ water consumption. The programme was implemented in 2012 by the
[...] Read more.
Affordability of services is a determinant for people’s level of access to water. In this study, we analyse the effect of a programme aimed at improving the affordability of water services on users’ water consumption. The programme was implemented in 2012 by the local government of the city of Bogotá, Colombia, intending to provide an essential “lifeline” volume of water to poor households free of charge. Our assessment was carried out with secondary data and used difference-in-difference estimators in a panel data analysis of a two-period sample: 2011 and 2014. The unit of analysis was defined based on the city’s administrative divisions and the socio-economic stratification of residences. Over the period analysed, beneficiaries’ household consumption increased, reaching per capita consumption levels closer to those of the upper strata of users. Results suggest that the programme contributes to increased consumption and equity among users. Full article
(This article belongs to the Special Issue Advances in the Economic Analysis of Residential Water Use)
Figures

Figure 1

Open AccessArticle Challenges to Sustainable Safe Drinking Water: A Case Study of Water Quality and Use across Seasons in Rural Communities in Limpopo Province, South Africa
Water 2018, 10(2), 159; doi:10.3390/w10020159
Received: 20 December 2017 / Revised: 16 January 2018 / Accepted: 16 January 2018 / Published: 7 February 2018
PDF Full-text (1875 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Consumption of microbial-contaminated water can result in diarrheal illnesses and enteropathy with the heaviest impact upon children below the age of five. We aimed to provide a comprehensive analysis of water quality in a low-resource setting in Limpopo province, South Africa. Surveys were
[...] Read more.
Consumption of microbial-contaminated water can result in diarrheal illnesses and enteropathy with the heaviest impact upon children below the age of five. We aimed to provide a comprehensive analysis of water quality in a low-resource setting in Limpopo province, South Africa. Surveys were conducted in 405 households in rural communities of Limpopo province to determine their water-use practices, perceptions of water quality, and household water-treatment methods. Drinking water samples were tested from households for microbiological contamination. Water from potential natural sources were tested for physicochemical and microbiological quality in the dry and wet seasons. Most households had their primary water source piped into their yard or used an intermittent public tap. Approximately one third of caregivers perceived that they could get sick from drinking water. All natural water sources tested positive for fecal contamination at some point during each season. The treated municipal supply never tested positive for fecal contamination; however, the treated system does not reach all residents in the valley; furthermore, frequent shutdowns of the treatment systems and intermittent distribution make the treated water unreliable. The increased water quantity in the wet season correlates with increased treated water from municipal taps and a decrease in the average contaminant levels in household water. This research suggests that wet season increases in water quantity result in more treated water in the region and that is reflected in residents’ water-use practices. Full article
Figures

Figure 1

Open AccessArticle Analysis of the Effects of Water Management Strategies and Climate Change on the Environmental and Agricultural Sustainability of Urmia Lake Basin, Iran
Water 2018, 10(2), 160; doi:10.3390/w10020160
Received: 17 December 2017 / Revised: 24 January 2018 / Accepted: 31 January 2018 / Published: 7 February 2018
PDF Full-text (5667 KB) | HTML Full-text | XML Full-text
Abstract
In arid and semi-arid areas, unsustainable development of irrigated agriculture has reduced the water level of large lakes such as Aral, Urmia, Hamoon, and Bakhtegan. Urmia Lake, as a hyper saline and very shallow lake, located in the northwest of Iran, has water
[...] Read more.
In arid and semi-arid areas, unsustainable development of irrigated agriculture has reduced the water level of large lakes such as Aral, Urmia, Hamoon, and Bakhtegan. Urmia Lake, as a hyper saline and very shallow lake, located in the northwest of Iran, has water level reductions of about 40 cm each year over the past two decades. In this research, the indices of environmental and agricultural sustainability are evaluated using performance criteria influenced by climate change and water management strategies for the Zarrinehrud and Siminehrud River basins as the largest sub-basin of Urmia Lake basin. Modeling of hydrologic behavior of these basins is performed using WEAP21 model. The model is analyzed for three future emission scenarios (A2, A1B, and B1), for the period of 2015–2040 and five water management scenarios: (1) keeping the existing situation; (2) crop pattern change; (3) improving the conveyance and distribution efficiency; (4) combining the improvement of conveyance and distribution efficiency with improving the application efficiency using modern technology; and (5) the combination of crop pattern change with the improvement of total irrigation efficiency. The results show that the highest values of indices of environmental sustainability and agricultural sustainability are related to the scenario of combining the crop pattern change with improving the total irrigation efficiency under the B1 emission scenario (B1S4). Full article
(This article belongs to the Special Issue Sustainable Water Management in Agriculture under Global Change)
Figures

Figure 1

Open AccessArticle Evaluation of the Digestibility of Attached and Suspended Growth Sludge in an Aerobic Digester for a Small Community
Water 2018, 10(2), 161; doi:10.3390/w10020161
Received: 7 August 2017 / Revised: 14 November 2017 / Accepted: 21 November 2017 / Published: 7 February 2018
PDF Full-text (2384 KB) | HTML Full-text | XML Full-text
Abstract
The aerobic sludge digestion process for waste sludge generated from suspended biomass (i.e., activated sludge process, ASP) and attached biomass (i.e., moving bed bioreactor, MBBR and modified packed bed biofilm, PBBR) reactors in a residential complex were analyzed. The rate of digestion with
[...] Read more.
The aerobic sludge digestion process for waste sludge generated from suspended biomass (i.e., activated sludge process, ASP) and attached biomass (i.e., moving bed bioreactor, MBBR and modified packed bed biofilm, PBBR) reactors in a residential complex were analyzed. The rate of digestion with respect to different sludge characteristics generated through these various treatment processes were examined; the results revealed that waste sludge from ASP took 16 days to achieve complete digestion while MBBR and PBBR took nine and seven days, respectively. The most important factors influencing the sludge digestion such as sludge volume index (SVI), mixed liquor suspended solid (MLSS), and mixed liquor volatile suspended solid (MLVSS) were examined. The ASP which had the highest initial MLSS and MLVS took a longer time for digestion. Aerobic sludge digestion in all the treatment reactors was studied under laboratory scale conditions in batch experimentation to evaluate sludge characteristics and the rate of digestion as well as through a continuous bench scale pilot system to optimize the process parameters. Removal efficiencies of volatile solids (VS) 90.71% in ASP, 84.27% in MBBR and 84.07% in PBBR in aerobic digestion during batch mode were also observed. The study revealed that the aerobic sludge digestion process utilized in curbing sludge is not feasible application for a small community due to very long digestion times and a large amount of space although Packed Bed Biofilm (PBBR) used the lowest time (seven days) compared to the other systems. Full article
Figures

Figure 1

Open AccessArticle Effect of Saturated Zone on Nitrogen Removal Processes in Stormwater Bioretention Systems
Water 2018, 10(2), 162; doi:10.3390/w10020162
Received: 9 December 2017 / Revised: 23 January 2018 / Accepted: 2 February 2018 / Published: 7 February 2018
PDF Full-text (4619 KB) | HTML Full-text | XML Full-text
Abstract
The introduction of a saturated zone (SZ) has been recommended to address the issue of nitrogen removal fluctuation in the bioretention system, which is one of the most versatile low-impact development facilities for urban stormwater management. Nine experimental columns were used to characterize
[...] Read more.
The introduction of a saturated zone (SZ) has been recommended to address the issue of nitrogen removal fluctuation in the bioretention system, which is one of the most versatile low-impact development facilities for urban stormwater management. Nine experimental columns were used to characterize the nitrogen concentration variations over the outflow during wetting periods and in SZ during the antecedent drying periods (ADPs), as well as compare removal efficiencies of various nitrogen species in systems with different SZ depths under alternate drying and wetting conditions. Results indicated that NO3-N concentrations in the outflow showed quasi-logistic curve-shaped variations over time: being low (<0.5 mg/L) in the early process, sharply increasing thereafter, and finally flattening around 3.0 mg/L with NO3 leaching; NH4+-N and organic nitrogen (ON) concentrations were consistently low around 0.5 mg/L and 1.8 mg/L, respectively during the wetting periods. NH4+ removal efficiency in bioretention systems was consistently high around 80%, not varying with the increasing SZ depth; ON removal efficiency had a slight rise from 57% to 84% and NO3 removal efficiency was significantly enhanced from −23% to 62% with the SZ depth increasing from 0 to 600 mm. Deeper SZ could store more runoff and promote more denitrification of NO3 and mineralization of ON during the ADPs, providing more “old” water with low NO3 and ON concentrations for water exchange with “new” inflow of higher NO3 and ON concentrations during the wetting periods. The total nitrogen (TN) removal, a combined result of the instantaneous removal through adsorption and retention in the upper soil layer during the wetting periods and the gradual removal via denitrification and mineralization in SZ during the ADPs, was also improved by increasing the SZ depth; TN removal efficiency was elevated from 35% to 73% when the SZ depth increased from zero to 600 mm. Full article
(This article belongs to the Special Issue Sponge Cities: Emerging Approaches, Challenges and Opportunities)
Figures

Open AccessArticle Cross-Scale Baroclinic Simulation of the Effect of Channel Dredging in an Estuarine Setting
Water 2018, 10(2), 163; doi:10.3390/w10020163
Received: 4 December 2017 / Revised: 20 January 2018 / Accepted: 31 January 2018 / Published: 7 February 2018
PDF Full-text (5130 KB) | HTML Full-text | XML Full-text
Abstract
Holistic simulation approaches are often required to assess human impacts on a river-estuary-coastal system, due to the intrinsically linked processes of contrasting spatial scales. In this paper, a Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) is applied in quantifying the impact of a
[...] Read more.
Holistic simulation approaches are often required to assess human impacts on a river-estuary-coastal system, due to the intrinsically linked processes of contrasting spatial scales. In this paper, a Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) is applied in quantifying the impact of a proposed hydraulic engineering project on the estuarine hydrodynamics. The project involves channel dredging and land expansion that traverse several spatial scales on an ocean-estuary-river-tributary axis. SCHISM is suitable for this undertaking due to its flexible horizontal and vertical grid design and, more importantly, its efficient high-order implicit schemes applied in both the momentum and transport calculations. These techniques and their advantages are briefly described along with the model setup. The model features a mixed horizontal grid with quadrangles following the shipping channels and triangles resolving complex geometries elsewhere. The grid resolution ranges from ~6.3 km in the coastal ocean to 15 m in the project area. Even with this kind of extreme scale contrast, the baroclinic model still runs stably and accurately at a time step of 2 min, courtesy of the implicit schemes. We highlight that the implicit transport solver alone reduces the total computational cost by 82%, as compared to its explicit counterpart. The base model is shown to be well calibrated, then it is applied in simulating the proposed project scenario. The project-induced modifications on salinity intrusion, gravitational circulation, and transient events are quantified and analyzed. Full article
Figures

Figure 1

Open AccessArticle Experimental and Numerical Study of Hydrodynamic Characteristics of Gullies for Buildings
Water 2018, 10(2), 165; doi:10.3390/w10020165
Received: 13 November 2017 / Revised: 19 January 2018 / Accepted: 5 February 2018 / Published: 7 February 2018
PDF Full-text (10334 KB) | HTML Full-text | XML Full-text
Abstract
The miniaturization of a gully for building drainage system is attempted by installing a streamlined bump in the discharge pipe to maintain the minimum water trap height of 50 mm. The hydrodynamic performances of the air–water flows with or without glass balls through
[...] Read more.
The miniaturization of a gully for building drainage system is attempted by installing a streamlined bump in the discharge pipe to maintain the minimum water trap height of 50 mm. The hydrodynamic performances of the air–water flows with or without glass balls through the two types of four-entry gullies with beveled or vertical nozzle flows are experimentally and numerically studied. The images of air–water–solid flow, maximum flow rates, self-purification properties and sustainable water traps subject to static and dynamic loadings are experimentally detected. The predictions of Computational Fluid Dynamics (CFD) unravel the characteristic flow structures to assist the interpretation of experimental results. In this respect, the observed entrained air bubbles and clustered glass balls in each gully correspond favorably to the regions with negative static pressures and weak flow momentums as disclosed by the CFD predictions. The measured ratios between discharged and supplied glass balls are consistently higher for the gully with beveled nozzle flows. The less efficient transportation of glass balls out of the drum for the gully with downward nozzle flow is attributed to the larger pressure gradients with considerable air entrainments. The relaxations of the form and friction drags over the nozzle-tip region and the reductions of air entrainments are essential for upgrading the maximum flow rate and the self-purification performance of a miniaturized gully. Full article
Figures

Figure 1

Open AccessArticle Comparison of Bootstrap Confidence Intervals Using Monte Carlo Simulations
Water 2018, 10(2), 166; doi:10.3390/w10020166
Received: 24 September 2017 / Revised: 11 January 2018 / Accepted: 29 January 2018 / Published: 8 February 2018
PDF Full-text (4463 KB) | HTML Full-text | XML Full-text
Abstract
Design of hydraulic works requires the estimation of design hydrological events by statistical inference from a probability distribution. Using Monte Carlo simulations, we compared coverage of confidence intervals constructed with four bootstrap techniques: percentile bootstrap (BP), bias-corrected bootstrap (BC), accelerated bias-corrected bootstrap (BCA)
[...] Read more.
Design of hydraulic works requires the estimation of design hydrological events by statistical inference from a probability distribution. Using Monte Carlo simulations, we compared coverage of confidence intervals constructed with four bootstrap techniques: percentile bootstrap (BP), bias-corrected bootstrap (BC), accelerated bias-corrected bootstrap (BCA) and a modified version of the standard bootstrap (MSB). Different simulation scenarios were analyzed. In some cases, the mother distribution function was fit to the random samples that were generated. In other cases, a distribution function different to the mother distribution was fit to the samples. When the fitted distribution had three parameters, and was the same as the mother distribution, the intervals constructed with the four techniques had acceptable coverage. However, the bootstrap techniques failed in several of the cases in which the fitted distribution had two parameters. Full article
Figures

Figure 1

Open AccessArticle A Risk-Based Model for Real-Time Flood Control Operation of a Cascade Reservoir System under Emergency Conditions
Water 2018, 10(2), 167; doi:10.3390/w10020167
Received: 13 December 2017 / Revised: 5 February 2018 / Accepted: 5 February 2018 / Published: 8 February 2018
Cited by 1 | PDF Full-text (4508 KB) | HTML Full-text | XML Full-text
Abstract
Real-time flood control operations of a cascade reservoir system under emergency conditions can reduce the social and economic loss caused by natural disasters. This paper proposes a risk-based model for real-time flood control operation of reservoirs under emergency conditions and uncertainties. The proposed
[...] Read more.
Real-time flood control operations of a cascade reservoir system under emergency conditions can reduce the social and economic loss caused by natural disasters. This paper proposes a risk-based model for real-time flood control operation of reservoirs under emergency conditions and uncertainties. The proposed model consists of three modules: emergency scenarios establishing, Monte Carlo simulations, and risk analysis. The emergency scenarios considered are earthquakes, extreme floods and failure of the spillways of a reservoir. The uncertainty factor considered is the forecast error of reservoir inflows, arising from model structural uncertainty and parameter estimating. The Monte Carlo simulations conduct the real-time flood control operation of reservoirs considering the proposed emergency events and uncertainties. The module of risk analysis performs the assessment of the operation schedules and calculates the risk of dam overtopping, based on the results from Monte Carlo simulations. The proposed model is applied to a cascade reservoir system in the upper reaches of Daduhe river basin in China. The results show that the maximum initial water level of the Shuangjiangkou reservoir is 2447 m a.s.l. (meters above sea level) using the release capacity model and is 2444.5 m a.s.l. using the command model under the scenario of upstream dam break. The integrated risk of the reservoir increases with the initial water level and the uncertainty degree of the reservoir inflows. The decision-makers can choose the operation models according to the actual initial water level of the reservoir under different emergency scenarios. Full article
Figures

Figure 1

Open AccessArticle Application of EMI and FDR Sensors to Assess the Fraction of Transpirable Soil Water over an Olive Grove
Water 2018, 10(2), 168; doi:10.3390/w10020168
Received: 27 November 2017 / Revised: 3 February 2018 / Accepted: 5 February 2018 / Published: 8 February 2018
PDF Full-text (8098 KB) | HTML Full-text | XML Full-text
Abstract
Accurate soil water status measurements across spatial and temporal scales are still a challenging task, specifically at intermediate spatial (0.1–10 ha) and temporal (minutes to days) scales. Consequently, a gap in knowledge limits our understanding of the reliability of the spatial measurements and
[...] Read more.
Accurate soil water status measurements across spatial and temporal scales are still a challenging task, specifically at intermediate spatial (0.1–10 ha) and temporal (minutes to days) scales. Consequently, a gap in knowledge limits our understanding of the reliability of the spatial measurements and its practical applicability in agricultural water management. This paper compares the cumulative EM38 (Geonics Ltd., Mississauga, ON, Canada) response collected by placing the sensor above ground with the corresponding soil water content obtained by integrating the values measured with an FDR (frequency domain reflectometry) sensor. In two field areas, characterized by different soil clay content, two Diviner 2000 access tubes (1.2 m) were installed and used to quantify the dimensionless fraction of transpirable soil water (FTSW). After the calibration, the work proposes the combined use of the FDR and electromagnetic induction (EMI) sensors to measure and map FTSW. A strong correlation (R2 = 0.86) between FTSW and EM38 bulk electrical conductivity was found. As a result, field changes of FTSW are due to the variability of soil water content and soil texture. As with the data acquired in the field, more structured patterns occurred after a wetting event, indicating the presence of subsurface flow or root water uptake paths. After assessing the relationship between the soil and crop water status, the FTSW domain includes a critical value, estimated around 0.38, below which a strong reduction of relative transpiration can be recognized. Full article
(This article belongs to the Special Issue Soil Water Conservation: Dynamics and Impact)
Figures

Figure 1

Open AccessArticle A Case Study of Preliminary Cost-Benefit Analysis of Building Levees to Mitigate the Joint Effects of Sea Level Rise and Storm Surge
Water 2018, 10(2), 169; doi:10.3390/w10020169
Received: 13 October 2017 / Revised: 28 January 2018 / Accepted: 29 January 2018 / Published: 8 February 2018
PDF Full-text (16612 KB) | HTML Full-text | XML Full-text
Abstract
Sea-level rise (SLR) will magnify the impacts of storm surge; the resulting severe flooding and inundation can cause huge damage to coastal communities. Community leaders are considering implementing adaptation strategies, typically hard engineering projects, to protect coastal assets and resources. It is important
[...] Read more.
Sea-level rise (SLR) will magnify the impacts of storm surge; the resulting severe flooding and inundation can cause huge damage to coastal communities. Community leaders are considering implementing adaptation strategies, typically hard engineering projects, to protect coastal assets and resources. It is important to understand the costs and benefits of the proposed project before any decision is made. To mitigate the flooding impact of joint effects of storm surge and SLR, building levee segments is chosen to be a corresponding adaptation strategy to protect the real estate assets in the study area—the City of Miami, FL, USA. This paper uses the classic Cost-Benefit Analysis (CBA) to assess the cost efficiency and proposes corresponding improvements in the benefit estimation, by estimating the avoided damages of implementing levee projects. Results show that the city will benefit from implementing levee projects along the Miami River in both a one-time 10 year storm event with SLR and cumulative long-term damage scenarios. This study also suggests that conducting CBA is a critical process before making coastal adaptation planning investment. A more meaningful result of cost effectiveness is estimated by accounting for the appreciation and time value. In addition, a sensitivity analysis is conducted to verify how the choice of discount rate influences the result. Uncertain factors including the rate of SLR, storm intensification, land use changes, and real estate appreciation are further analyzed. Full article
Figures

Figure 1

Open AccessArticle Agricultural Water Use Sustainability Assessment in the Tarim River Basin under Climatic Risks
Water 2018, 10(2), 170; doi:10.3390/w10020170
Received: 1 December 2017 / Revised: 1 February 2018 / Accepted: 6 February 2018 / Published: 8 February 2018
Cited by 1 | PDF Full-text (5284 KB) | HTML Full-text | XML Full-text
Abstract
Proper agricultural water management in arid regions is the key to tackling climatic risks. However, an effective assessment of the current response to climate change in agricultural water use is the precondition for a group adaptation strategy. The paper, taking the Tarim River
[...] Read more.
Proper agricultural water management in arid regions is the key to tackling climatic risks. However, an effective assessment of the current response to climate change in agricultural water use is the precondition for a group adaptation strategy. The paper, taking the Tarim River basin (TRB) as an example, aims to examine the agricultural water use sustainability of water resource increase caused by climatic variability. In order to describe the response result, groundwater change has been estimated based on the Gravity Recovery and Climate Experiment (GRACE) and the Global Land Data Assimilation System (GLDAS)–Noah land surface model (NOAH) data. In order to better understand the relationship between water resource increase and agricultural water consumption, an agricultural water stress index has been established. Agricultural water stress has been in a severe state during the whole period, although it alleviated somewhat in the mid–late period. This paper illustrates that an increase in water supply could not satisfy agricultural production expansion. Thus, seasonal groundwater loss and a regional water shortage occurred. Particularly in 2008 and 2009, the sharp shortage of water supply in the Tarim River basin directly led to a serious groundwater drop by nearly 20 mm from the end of 2009 to early 2010. At the same time, a regional water shortage led to water scarcity for the whole basin, because the water consumption, which was mainly distributed around Source Rivers, resulted in break-off discharge in the mainstream. Therefore, current agricultural development in the Tarim River basin is unsustainable in the context of water supply under climatic risks. Under the control of irrigation, spatial and temporal water allocation optimization is the key to the sustainable management of the basin. Full article
(This article belongs to the Special Issue Sustainable Water Management within Inland River Watershed)
Figures

Figure 1

Open AccessArticle Continuously Tracking the Annual Changes of the Hengsha and Changxing Islands at the Yangtze River Estuary from 1987 to 2016 Using Landsat Imagery
Water 2018, 10(2), 171; doi:10.3390/w10020171
Received: 5 December 2017 / Revised: 28 January 2018 / Accepted: 2 February 2018 / Published: 8 February 2018
PDF Full-text (8988 KB) | HTML Full-text | XML Full-text
Abstract
The evolution of estuarine islands is potentially controlled by sediment discharge, tidal currents, sea level rise, and intensive human activities. An understanding of the spatial and temporal changes of estuarine islands is needed for environmental change monitoring and assessment in estuarine and coastal
[...] Read more.
The evolution of estuarine islands is potentially controlled by sediment discharge, tidal currents, sea level rise, and intensive human activities. An understanding of the spatial and temporal changes of estuarine islands is needed for environmental change monitoring and assessment in estuarine and coastal areas. Such information can also help us better understand how estuarine islands respond to sea level rise in the context of global warming. The temporal changes of two estuarine islands in Shanghai near the Yangtze River Estuary were obtained using Landsat TM (Thematic Mapper) and ETM+ (Enhanced Thematic Mapper) images from 1987 to 2016 on an annual scale. First, a composite image was generated by using the multi-temporal Landsat images for each year. Then, a modified normalized difference water index (MNDWI) was applied to the annual estuarine island maps using a threshold segmentation method. Finally, we obtained the temporal changes of the estuarine islands in Shanghai during the period 1987–2016. The results suggest that (1) Landsat TM/ETM+ images can be used for estuarine island mapping and change detection; (2) the two estuarine islands have expanded significantly during the past three decades; (3) human activities are the main driving factor that caused the expansion of the estuarine islands; and (4) the sea level can also partly explain the change in the estuarine islands. This study demonstrates that Landsat data are useful for determining the annual variations in the land area of two estuarine islands in Shanghai during the past 30 years. In the future, other factors and their contributions to estuarine island changes should be further investigated. Full article
Figures

Open AccessArticle Flood Mitigation by Permeable Pavements in Chinese Sponge City Construction
Water 2018, 10(2), 172; doi:10.3390/w10020172
Received: 29 November 2017 / Revised: 4 February 2018 / Accepted: 6 February 2018 / Published: 9 February 2018
PDF Full-text (1676 KB) | HTML Full-text | XML Full-text
Abstract
It is important to evaluate the effectiveness of permeable pavements on flood mitigation at different spatial scales for their effective application, for example, sponge city construction in China. This study evaluated the effectiveness of three types of permeable pavements (i.e., permeable asphalts (PA),
[...] Read more.
It is important to evaluate the effectiveness of permeable pavements on flood mitigation at different spatial scales for their effective application, for example, sponge city construction in China. This study evaluated the effectiveness of three types of permeable pavements (i.e., permeable asphalts (PA), permeable concretes (PC), and permeable interlocking concrete pavers (PICP)) on flood mitigation at a community scale in China using a hydrological model. In addition, the effects of clogging and initial water content in permeable pavements on flood mitigation performance were assessed. The results indicated that in 12 scenarios, permeable pavements reduced total surface runoff by 1–40% and peak flow by 7–43%, respectively. The hydrological performance of permeable pavements was limited by clogging and initial water content. Clogging resulted in the effectiveness on total surface runoff reduction and peak flow reduction being decreased by 62–92% and 37–65%, respectively. By increasing initial water content at the beginning of the simulation, the effectiveness of total runoff reduction and peak flow reduction decreased by 57–85% and 37–67%, respectively. Overall, among the three types of permeable pavements, PC without clogging had the best performance in terms of flood mitigation, and PICP was the least prone to being clogged. Our findings demonstrate that both the type and the maintenance of permeable pavements have significant effects on their performance in the flood mitigation. Full article
Figures

Figure 1

Open AccessArticle Urban Estuarine Beaches and Urban Water Cycle Seepage: The Influence of Temporal Scales
Water 2018, 10(2), 173; doi:10.3390/w10020173
Received: 4 October 2017 / Revised: 18 December 2017 / Accepted: 6 February 2018 / Published: 9 February 2018
PDF Full-text (2659 KB) | HTML Full-text | XML Full-text
Abstract
Temperate estuarine beaches are an asset to coastal cities. Being located within the transition zone where the river meets the sea can provide several environmental benefits such as warm water temperature during the summer, flat waters, protection from coastal upwelling-induced morning fog, as
[...] Read more.
Temperate estuarine beaches are an asset to coastal cities. Being located within the transition zone where the river meets the sea can provide several environmental benefits such as warm water temperature during the summer, flat waters, protection from coastal upwelling-induced morning fog, as well as additional recreational and cultural values. In this study we address a major question—can the urban water cycle impair the water quality dynamics during a bathing season in a temperate Atlantic estuary (Douro, Northwest Portugal)? Water quality was assessed according to the EU legal criteria at different time scales. No daily, weekly, or monthly patterns for microbiological descriptors were found, which rather followed the hourly tidal dynamics. Quality decreased during high tide, affecting potentially 800+ beach-users during mid-summer weekends (4 m2 per person). Low water quality was transported upstream from highly populated urban areas. Therefore, the understanding of the dynamics of estuarine systems is essential to adapt the standard official approach, and the obtained results can be used to draw policy recommendations to improve the sampling strategy, aiming for more accurate assessment of the water quality to reduce the risk hazard of estuarine beaches. Full article
(This article belongs to the Special Issue Urban Water Cycle Modelling and Management)
Figures

Figure 1

Open AccessArticle 3-D Numerical Investigation on Oxygen Transfer in a Horizontal Venturi Flow with Two Holes
Water 2018, 10(2), 174; doi:10.3390/w10020174
Received: 12 December 2017 / Revised: 13 January 2018 / Accepted: 1 February 2018 / Published: 9 February 2018
PDF Full-text (2301 KB) | HTML Full-text | XML Full-text
Abstract
In order to investigate the dissolved oxygen increase caused by air suction in a horizontal Venturi flow with two holes, a 3-D computational fluid dynamics model was used to explore the water and bubble mixture flow, coupled with a dissolved oxygen transfer model.
[...] Read more.
In order to investigate the dissolved oxygen increase caused by air suction in a horizontal Venturi flow with two holes, a 3-D computational fluid dynamics model was used to explore the water and bubble mixture flow, coupled with a dissolved oxygen transfer model. A series of experiments were conducted to validate the mathematical model. A relative saturation coefficient correlation was examined factoring in dissolved oxygen concentration at the inlet, water velocity at the inlet, the hole’s diameter, contraction ratio at throat section, and the downstream length of Venturi pipe. It was found that the relative saturation coefficient increases with increasing dissolved oxygen concentration at the inlet and downstream length of Venturi pipe respectively. However, it increases with decreasing water velocity at the inlet and contraction ratio at the throat section to some extent. The hole’s diameter plays a complex role in the relative saturation coefficient. The dimensional analysis method and the least square method were used to deduce a simple formula for the relative saturation coefficient, and this was consistent with related data. Full article
Figures

Figure 1

Open AccessArticle Stochastic Linear Programming for Reservoir Operation with Constraints on Reliability and Vulnerability
Water 2018, 10(2), 175; doi:10.3390/w10020175
Received: 16 December 2017 / Revised: 6 February 2018 / Accepted: 6 February 2018 / Published: 9 February 2018
PDF Full-text (1151 KB) | HTML Full-text | XML Full-text
Abstract
Reliability and vulnerability (RV) are two very important performance measures but, due to their stage-inseparable nature, they cannot be explicitly incorporated in stochastic dynamic programming (SDP), which is extensively used in reservoir operation. With inflows described as a Markov chain, a stochastic linear
[...] Read more.
Reliability and vulnerability (RV) are two very important performance measures but, due to their stage-inseparable nature, they cannot be explicitly incorporated in stochastic dynamic programming (SDP), which is extensively used in reservoir operation. With inflows described as a Markov chain, a stochastic linear programming (SLP) model is formulated in this paper to explicitly incorporate the RV constraints in the reservoir operation, aimed at maximizing the expected power generation by determining the optimal scheduling decisions and their probabilities. Simulation results of the SLP and SDP models indicate the equivalence of the proposed SLP and SDP models without considering the RV constraints, as well as the strength of the SLP in explicitly incorporating the RV constraints. A simulated scheduling solution also reveals a reduction of power generation fluctuation, with the reservoir capacity emptied in advance to meet given reliability and vulnerability. Full article
(This article belongs to the Special Issue Adaptive Catchment Management and Reservoir Operation)
Figures

Figure 1

Open AccessArticle Simulation of Groundwater Flow and Migration of the Radioactive Cobalt-60 from LAMA Nuclear Facility-Iraq
Water 2018, 10(2), 176; doi:10.3390/w10020176
Received: 30 June 2017 / Revised: 22 January 2018 / Accepted: 25 January 2018 / Published: 9 February 2018
PDF Full-text (7184 KB) | HTML Full-text | XML Full-text
Abstract
This study provides a simulation of groundwater flow and advective-dispersive migration of radioactive Co-60 through an aquifer with three layers, which release or leak to groundwater from the Active Metallurgy Testing Laboratory (LAMA) Nuclear Facility-Iraq due to the nuclear accident scenario. Processing Modflow
[...] Read more.
This study provides a simulation of groundwater flow and advective-dispersive migration of radioactive Co-60 through an aquifer with three layers, which release or leak to groundwater from the Active Metallurgy Testing Laboratory (LAMA) Nuclear Facility-Iraq due to the nuclear accident scenario. Processing Modflow for windows (PMWIN) and Modular Three-Dimensional Multispecies Transport (MT3DMS) Models were used for this purpose. The study area and the contaminated area were 12.7 km2 and 0.005625 km2, respectively. Water levels of the groundwater have been measured in six monitoring wells. The simulation time was assumed to have started in 2016. The PMWIN model simulated the flow for two scenarios of water level in Tigris River (average and minimum water levels). The MT3DMS model simulated 10 years of plume travel, beginning in 2016. The simulated Co-60 concentrations after five years of travel were 32.34 and 34.44 μg/m3 for the two scenarios. The maximum predicted Co-60 concentrations at the end of Year 10 were 34.86 and 37.31 μg/m3, respectively. The sensitivity analysis showed that the simulated hydraulic heads in the observation wells and the simulated plume of Co-60 were highly sensitive to changes in the effective porosity but less sensitive to changes in other parameters of the dispersion and chemical reaction processes. The time necessary to reach steady state condition was predicted to be approximately 16 years. The contaminated area was isolated by using remedial process which is represented by three fully penetrating pumping wells with a suitable flow rate (0.045 m3/s) for controlling the movement of Co-60 pollutant. Full article
(This article belongs to the Special Issue Isotopes in Hydrology and Hydrogeology)
Figures

Figure 1

Open AccessArticle Comparison of Precipitation and Streamflow Correcting for Ensemble Streamflow Forecasts
Water 2018, 10(2), 177; doi:10.3390/w10020177
Received: 11 November 2017 / Revised: 25 January 2018 / Accepted: 6 February 2018 / Published: 9 February 2018
PDF Full-text (2788 KB) | HTML Full-text | XML Full-text
Abstract
Meteorological centers constantly make efforts to provide more skillful seasonal climate forecast, which has the potential to improve streamflow forecasts. A common approach is to bias-correct the general circulation model (GCM) forecasts prior to generating the streamflow forecasts. Less attention has been paid
[...] Read more.
Meteorological centers constantly make efforts to provide more skillful seasonal climate forecast, which has the potential to improve streamflow forecasts. A common approach is to bias-correct the general circulation model (GCM) forecasts prior to generating the streamflow forecasts. Less attention has been paid to the issue of bias-corrected streamflow forecasts that were generated by GCM forecasts. This study compares the effect of bias-corrected GCM forecasts and bias-corrected streamflow outputs on the improvement of streamflow forecast efficiency. Based on the Upper Hanjiang River Basin (UHRB), the authors compare three forecasting scenarios: original forecasts, bias-corrected precipitation forecasts and bias-corrected streamflow forecasts. We apply the quantile mapping method to bias-correct precipitation forecasts and the linear scaling method to bias-correct the original streamflow forecasts. A semi-distributed hydrological model, namely the Tsinghua Representative Elementary Watershed (THREW) model, is employed to transform precipitation into streamflow. The effects of bias-corrected precipitation and bias-corrected streamflow are assessed in terms of accuracy, reliability, sharpness and overall performance. The results show that both bias-corrected precipitation and bias-corrected streamflow can considerably increase the overall forecast skill in comparison to the original streamflow forecasts. Bias-corrected precipitation contributes mainly to improving the forecast reliability and sharpness, while bias-corrected streamflow is successful in increasing the forecast accuracy and overall performance of the ensemble forecasts. Full article
Figures

Figure 1

Open AccessArticle Decline of N and P Uptake in the Inner Protection Zone of a Terminal Reservoir during Inter-Basin Water Transfers
Water 2018, 10(2), 178; doi:10.3390/w10020178
Received: 23 December 2017 / Revised: 1 February 2018 / Accepted: 6 February 2018 / Published: 9 February 2018
PDF Full-text (21905 KB) | HTML Full-text | XML Full-text
Abstract
Inter-basin water transfer projects are designed to relieve water scarcity around the world. However, ecological problems relating to reductions in protection zone functions can occur during inter-basin transfers. This paper uses the largest inter-basin water transfer project in the world, namely, the South-to-North
[...] Read more.
Inter-basin water transfer projects are designed to relieve water scarcity around the world. However, ecological problems relating to reductions in protection zone functions can occur during inter-basin transfers. This paper uses the largest inter-basin water transfer project in the world, namely, the South-to-North Water Transfer Project (SNWTP) in China, as an example to analyze the variation of Miyun Reservoir’s inner protection zone functions when water is transferred. Specifically, a riparian model (RIPAM) coupled with remote sensing data were used to calculate the nitrogen (N) and phosphorus (P) losses due to plant uptake, and these results were validated by in situ survey data. Then, correlations between water levels and N and P removal were analyzed. The results show that water table disturbances resulting from elevated water levels strongly influence the growth of plants and have obvious negative impacts on N and P removal in the inner protection zone. With the implementation of the middle route of the SNWTP, the water level of Miyun will rise to 150 m in 2020, and subsequently, the total net primary productivity (NPP) could decline by more than 40.90% from the level in 2015, while the N and P uptake could decline by more than 53.03% and 43.49%, respectively, from the levels in 2015, according to the modeling results. This will lead to declines in the inner protection zone’s defense effectiveness for N and P interception and increases in risks to the security of water resources. The results of this study provide useful knowledge for managing the defense function of the terminal reservoir’s inner protection zone and for ensuring that water quality is maintained during the diversion process. Full article
(This article belongs to the Special Issue Adaptive Catchment Management and Reservoir Operation)
Figures

Figure 1

Open AccessArticle Return Level Estimation of Extreme Rainfall over the Iberian Peninsula: Comparison of Methods
Water 2018, 10(2), 179; doi:10.3390/w10020179
Received: 30 November 2017 / Revised: 29 January 2018 / Accepted: 2 February 2018 / Published: 9 February 2018
PDF Full-text (4598 KB) | HTML Full-text | XML Full-text
Abstract
Different ways to estimate future return levels (RLs) for extreme rainfall, based on extreme value theory (EVT), are described and applied to the Iberian Peninsula (IP). The study was done for an ensemble of high quality rainfall time series observed in the IP
[...] Read more.
Different ways to estimate future return levels (RLs) for extreme rainfall, based on extreme value theory (EVT), are described and applied to the Iberian Peninsula (IP). The study was done for an ensemble of high quality rainfall time series observed in the IP during the period 1961–2010. Two approaches, peaks-over-threshold (POT) and block maxima (BM) with the generalized extreme value (GEV) distribution, were compared in order to identify which is the more appropriate for the estimation of RLs. For the first approach, which identifies trends in the parameters of the asymptotic distributions of extremes, both all-days and rainy-days-only datasets were considered because a major fraction of values of daily rainfall over the IP is zero. For the second approach, rainy-days-only data were considered showing how the mean, variance and number of rainy days evolve. The 20-year RLs expected for 2020 were estimated using these methods for three seasons: autumn, spring and winter. The GEV is less reliable than the POT because fixed blocks lead to the selection of non-extreme values. Future RLs obtained with the POT are greater than those estimated with the GEV, mainly because some gauges show significant positive trends for the number of rainy days. Autumn, rather than winter, is currently the season with the heaviest rainfall for some regions. Full article
Figures

Figure 1

Open AccessArticle Urban Floods and Climate Change Adaptation: The Potential of Public Space Design When Accommodating Natural Processes
Water 2018, 10(2), 180; doi:10.3390/w10020180
Received: 28 December 2017 / Revised: 28 January 2018 / Accepted: 7 February 2018 / Published: 9 February 2018
PDF Full-text (3097 KB) | HTML Full-text | XML Full-text
Abstract
Urban public space is extraordinarily adaptable under a pattern of relatively stable changes. However, when facing unprecedented and potentially extreme climatic changes, public spaces may not have the same adaptation capacity. In this context, planned adaptation gains strength against “business as usual”. While
[...] Read more.
Urban public space is extraordinarily adaptable under a pattern of relatively stable changes. However, when facing unprecedented and potentially extreme climatic changes, public spaces may not have the same adaptation capacity. In this context, planned adaptation gains strength against “business as usual”. While public spaces are among the most vulnerable areas to climatic hazards, they entail relevant characteristics for adaptation efforts. As such, public space design can lead to effective adaptation undertakings, explicitly influencing urban design practices as we know them. Amongst its different intrinsic roles and benefits, such as being a civic common gathering place of social and economic exchanges, public space may have found an enhanced protagonism under the climate change adaptation perspective. In light of the conducted empirical analysis, which gathered existing examples of public spaces with flood adaptation purposes, specific public space potentialities for the application of flood adaptation measures are here identified and characterized. Overall, this research questions the specific social potentiality of public space adaptation in the processes of vulnerability tackling, namely considering the need of alternatives in current flood management practices. Through literature review and case study analysis, it is here argued that: people and communities can be perceived as more than susceptible targets and rather be professed as active agents in the process of managing urban vulnerability; that climate change literacy, through the design of a public space, may endorse an increased common need for action and the pursuit of suitable solutions; and that local know-how and locally-driven design can be considered as a service with added value for adaptation endeavors. Full article
Figures

Figure 1

Open AccessArticle Ecohydrologic Connections in Semiarid Watershed Systems of Central Oregon USA
Water 2018, 10(2), 181; doi:10.3390/w10020181
Received: 26 December 2017 / Revised: 31 January 2018 / Accepted: 5 February 2018 / Published: 9 February 2018
PDF Full-text (29214 KB) | HTML Full-text | XML Full-text
Abstract
An improved understanding of ecohydrologic connections is critical for improving land management decisions in water-scarce regions of the western United States. For this study, conducted in a semiarid (358 mm) rangeland location in central Oregon, we evaluated precipitation-interception-soil moisture dynamics at the plot
[...] Read more.
An improved understanding of ecohydrologic connections is critical for improving land management decisions in water-scarce regions of the western United States. For this study, conducted in a semiarid (358 mm) rangeland location in central Oregon, we evaluated precipitation-interception-soil moisture dynamics at the plot scale and characterized surface water and groundwater relations across the landscape including areas with and without western juniper (Juniperus occidentalis). Results from this study show that juniper woodlands intercepted up to 46% of total precipitation, altering soil moisture distribution under the canopy and in the interspace. Results indicate that precipitation reaching the ground can rapidly percolate through the soil profile and into the shallow aquifer, and that strong hydrologic connections between surface and groundwater components exist during winter precipitation and snowmelt runoff seasons. Greater streamflow and springflow rates were observed in the treated watershed when compared to the untreated. Streamflow rates up to 1020 L min−1 and springflow rates peaking 190 L min−1 were observed in the watershed where juniper was removed 13 years ago. In the untreated watershed, streamflow rates peaked at 687 L min−1 and springflow rates peaked at 110 L min−1. Results contribute to improved natural resource management through a better understanding of the biophysical connections occurring in rangeland ecosystems and the role that woody vegetation encroachment may have on altering the hydrology of the site. Full article
Figures

Figure 1