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Water, Volume 8, Issue 1 (January 2016)

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Open AccessEditorial Acknowledgement to Reviewers of Water in 2015
Water 2016, 8(1), 33; https://doi.org/10.3390/w8010033
Received: 21 January 2016 / Accepted: 21 January 2016 / Published: 21 January 2016
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Abstract
The editors of Water would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2015. [...] Full article
Open AccessArticle Spatial and Temporal Distribution of Soil Moisture at the Catchment Scale Using Remotely-Sensed Energy Fluxes
Water 2016, 8(1), 32; https://doi.org/10.3390/w8010032
Received: 1 December 2015 / Revised: 12 January 2016 / Accepted: 15 January 2016 / Published: 21 January 2016
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Abstract
Despite playing a critical role in the division of precipitation between runoff and infiltration, soil moisture (SM) is difficult to estimate at the catchment scale and at frequent time steps, as is required by many hydrological, erosion and flood simulation models. In this
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Despite playing a critical role in the division of precipitation between runoff and infiltration, soil moisture (SM) is difficult to estimate at the catchment scale and at frequent time steps, as is required by many hydrological, erosion and flood simulation models. In this work, an integrated methodology is described to estimate SM at the root zone, based on the remotely-sensed evaporative fraction (Λ) and ancillary information on soil and meteorology. A time series of Terra MODIS satellite images was used to estimate SM maps with an eight-day time step at a 250-m spatial resolution for three diverse catchments in Europe. The study of the resulting SM maps shows that their spatial variability follows the pattern of land cover types and the main geomorphological features of the catchment, and their temporal pattern follows the distribution of rain events, with the exception of irrigated land. Field surveys provided in situ measurements to validate the SM maps’ accuracy, which proved to be variable according to site and season. In addition, several factors were analyzed in order to explain the variation in the accuracy, and it was shown that the land cover type, the soil texture class, the temporal difference between the datasets’ acquisition and the presence of rain events during the measurements played a significant role, rather than the often referred to scale difference between in situ and satellite observations. Therefore, the proposed methodology can be used operationally to estimate SM maps at the catchment scale, with a 250-m spatial resolution and an eight-day time step. Full article
(This article belongs to the Special Issue Remote Sensing of Soil Moisture)
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Open AccessArticle Effects of the “Run-of-River” Hydro Scheme on Macroinvertebrate Communities and Habitat Conditions in a Mountain River of Northeastern China
Water 2016, 8(1), 31; https://doi.org/10.3390/w8010031
Received: 30 October 2015 / Revised: 11 January 2016 / Accepted: 12 January 2016 / Published: 21 January 2016
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Abstract
The main objective of this study was to quantify the impacts of the run of river (ROR) scheme on the instream habitat and macroinvertebrate community. We sampled the macroinvertebrate assemblages and collected the habitat variables above and below an ROR hydropower plant: Aotou
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The main objective of this study was to quantify the impacts of the run of river (ROR) scheme on the instream habitat and macroinvertebrate community. We sampled the macroinvertebrate assemblages and collected the habitat variables above and below an ROR hydropower plant: Aotou plant in the Hailang River, China. The effects of the ROR scheme on habitat conditions were examined using regulation-related variables, most of which, particularly the hydrological variables and substrate composition, presented spatial variations along the downstream direction, contributing to heterogeneous conditions between reaches. The macroinvertebrate richness, the density and the diversity metrics showed significant decreases in the “depleted” reach compared with the upper and lower reaches. Approximately 75% of reach-averaged densities and 50% of taxa richness suffered decreases in the “depleted” reach compared with the upper reach. Furthermore, functional feeding groups also showed distinct site differences along the channel. The relative abundance of both collector-gatherers and the scrapers reduced considerably at the “depleted” sites, particularly at the site immediately downstream of the weir. The total variance in the the functional feeding group (FFG) data explained by Canonical correlation analysis (CCA) was more than 81.4% and the high-loadings factors were depth, flow velocity, DO and substrate composition. We demonstrated that flow diversion at the 75% level and an in-channel barrier, due to the ROR scheme, are likely to lead to poor habitat conditions and decrease both the abundance and the diversity of macroinvertebrates in reaches influenced by water diversion. Full article
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Open AccessReview Rain Drop Measurement Techniques: A Review
Water 2016, 8(1), 29; https://doi.org/10.3390/w8010029
Received: 17 November 2015 / Revised: 15 December 2015 / Accepted: 4 January 2016 / Published: 21 January 2016
Cited by 11 | PDF Full-text (2290 KB) | HTML Full-text | XML Full-text
Abstract
For over a century there have been many studies that describe the use of rain drop measurement techniques. Initial manual measurement methods evolved due to improved technology to include photographic and, more recently, automated disdrometer and laser measurement techniques. Despite these numerous studies,
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For over a century there have been many studies that describe the use of rain drop measurement techniques. Initial manual measurement methods evolved due to improved technology to include photographic and, more recently, automated disdrometer and laser measurement techniques. Despite these numerous studies, there have been few comparative reviews of the range of methodologies, and their relative performance. This review explores the raindrop measurement techniques available, and summarizes and classifies the techniques according to the method or principle involved. The requirements of a robust raindrop measurement technique are suggested, and these are reviewed against existing rain drop measurement techniques to provide a comparative guide to the use of the range of techniques available for any research study. This review revealed that while advances in technology have allowed many of the deficiencies of early techniques to be eliminated, challenges remain in relation to the precision of the measurement of the size, shape, and velocity of rain drops. Full article
(This article belongs to the Special Issue Urban Drainage and Urban Stormwater Management)
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Open AccessArticle Anthropogenic Nitrogen and Phosphorus Emissions and Related Grey Water Footprints Caused by EU-27′s Crop Production and Consumption
Water 2016, 8(1), 30; https://doi.org/10.3390/w8010030
Received: 19 October 2015 / Revised: 5 January 2016 / Accepted: 14 January 2016 / Published: 20 January 2016
Cited by 7 | PDF Full-text (1293 KB) | HTML Full-text | XML Full-text
Abstract
Water is a prerequisite for life on our planet. Due to climate change and pollution, water availability for agricultural production, industry and households is increasingly put at risk. With agriculture being the largest water user as well as polluter worldwide, we estimate anthropogenic
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Water is a prerequisite for life on our planet. Due to climate change and pollution, water availability for agricultural production, industry and households is increasingly put at risk. With agriculture being the largest water user as well as polluter worldwide, we estimate anthropogenic nitrogen and phosphorus emissions to fresh water related to global crop production at a spatial resolution level of 5 by 5 arc min and calculate the grey water footprints (GWF) related to EU-27′s crop production. A multiregional input-output model is used to trace the the GWF embodied in the final consumption of crop products by the EU-27. The total GWF related to crop production in the EU-27 in 2007 was 1 × 1012 m3/year. Spain contributed about 40% to this total. Production of cereals (wheat, rice and other cereals) take the largest share, accounting for 30% of the GWF, followed by fruits (17%), vegetables (14%), and oil crops (13%). The total agricultural GWF of the EU-27 related to crop consumption was 1830 billion m3/year, which is 3700 m3/year per capita on average. Overall, the EU-27 was able to externalize about 41% of the GWF to the rest of the world through imports of crop products. Full article
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Open AccessArticle Extraction and Preference Ordering of Multireservoir Water Supply Rules in Dry Years
Water 2016, 8(1), 28; https://doi.org/10.3390/w8010028
Received: 19 October 2015 / Revised: 9 January 2016 / Accepted: 13 January 2016 / Published: 20 January 2016
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Abstract
This paper presents a new methodology of combined use of the nondominated sorting genetic algorithm II (NSGA-II) and the approach of successive elimination of alternatives based on order and degree of efficiency (SEABODE) in identifying the most preferred multireservoir water supply rules in
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This paper presents a new methodology of combined use of the nondominated sorting genetic algorithm II (NSGA-II) and the approach of successive elimination of alternatives based on order and degree of efficiency (SEABODE) in identifying the most preferred multireservoir water supply rules in dry years. First, the suggested operation rules consists of a two-point type time-varying hedging policy for a single reservoir and a simple proportional allocation policy of common water demand between two parallel reservoirs. Then, the NSGA-II is employed to derive enough noninferior operation rules (design alternatives) in terms of two conflicting objectives (1) minimizing the total deficit ratio (TDR) of all demands of the entire system in operation horizon, and (2) minimizing the maximum deficit ratio (MDR) of water supply in a single period. Next, the SEABODE, a multicriteria decision making (MCDM) procedure, is applied to further eliminate alternatives based on the concept of efficiency of order k with degree p. In SEABODE, the reservoir performance indices and water shortage indices are selected as evaluation criteria for preference ordering among the design alternatives obtained by NSGA-II. The proposed methodology was tested on a regional water supply system with three reservoirs located in the Jialing River, China, where the results demonstrate its applicability and merits. Full article
(This article belongs to the collection Water Policy Collection)
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Open AccessArticle Spatial Distribution of Benthic Macroinvertebrate Assemblages in Relation to Environmental Variables in Korean Nationwide Streams
Water 2016, 8(1), 27; https://doi.org/10.3390/w8010027
Received: 23 October 2015 / Revised: 13 January 2016 / Accepted: 15 January 2016 / Published: 20 January 2016
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Abstract
Conserving and enhancing freshwater biodiversity are global issues to ensure ecosystem integrity and sustainability. To meet this, it is critical to understand how the biological assemblages are determined by environmental gradients in different spatial scales. Nevertheless, information on their large-scale environmental relationships remains
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Conserving and enhancing freshwater biodiversity are global issues to ensure ecosystem integrity and sustainability. To meet this, it is critical to understand how the biological assemblages are determined by environmental gradients in different spatial scales. Nevertheless, information on their large-scale environmental relationships remains scarce in Korea. We aimed to understand nationwide spatial distribution patterns of benthic macroinvertebrates and important environmental factors affecting their distribution in 388 streams and rivers across Korea. A total of 340 taxa, belonging to 113 families in 23 orders of five phyla, were identified. Assemblage composition in most Korean streams included a few predominant colonizers and a majority of rare taxa. Cluster analysis based on benthic macroinvertebrates classified a total of 720 sampling sites into five clusters according to the pollution levels from fast-flowing less polluted streams with low electrical conductivity to moderately or severely polluted streams with high electrical conductivity and slow water velocity. Canonical correspondence analysis revealed that altitude, water velocity and streambed composition were the most important determinants, rather than watershed and water chemistry variables, for explaining the variation in macroinvertebrate assemblage patterns. The results provide basic information for establishing the conservation and restoration strategies of macroinvertebrate biodiversity against anthropogenic disturbances and developing more confident bio-assessment tools for diagnosing stream ecosystem integrity. Full article
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Open AccessArticle Implications of Texture and Erodibility for Sediment Retention in Receiving Basins of Coastal Louisiana Diversions
Water 2016, 8(1), 26; https://doi.org/10.3390/w8010026
Received: 15 November 2015 / Revised: 8 January 2016 / Accepted: 12 January 2016 / Published: 20 January 2016
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Abstract
Although the Mississippi River deltaic plain has been the subject of abundant research over recent decades, there is a paucity of data concerning field measurement of sediment erodibility in Louisiana estuaries. Two contrasting receiving basins for active diversions were studied: West Bay on
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Although the Mississippi River deltaic plain has been the subject of abundant research over recent decades, there is a paucity of data concerning field measurement of sediment erodibility in Louisiana estuaries. Two contrasting receiving basins for active diversions were studied: West Bay on the western part of Mississippi River Delta and Big Mar, which is the receiving basin for the Caernarvon freshwater diversion. Push cores and water samples were collected at six stations in West Bay and six stations in Big Mar. The average erodibility of Big Mar sediment was similar to that of Louisiana shelf sediment, but was higher than that of West Bay. Critical shear stress to suspend sediment in both West Bay and Big Mar receiving basins was around 0.2 Pa. A synthesis of 1191 laser grain size data from surficial and down-core sediment reveals that silt (4–63 μm) is the largest fraction of retained sediment in receiving basins, larger than the total of sand (>63 μm) and clay (<4 μm). It is suggested that preferential delivery of fine grained sediment to more landward and protected receiving basins would enhance mud retention. In addition, small fetch sizes and fragmentation of large receiving basins are favorable for sediment retention. Full article
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Open AccessArticle Hydraulic Transients Caused by Air Expulsion During Rapid Filling of Undulating Pipelines
Water 2016, 8(1), 25; https://doi.org/10.3390/w8010025
Received: 15 October 2015 / Revised: 11 January 2016 / Accepted: 12 January 2016 / Published: 19 January 2016
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Abstract
One of the main issues arising during the rapid filling of a pipeline is the pressure transient which originates after the entrapped air has been expelled at the air release valve. Because of the difference in density between water and air, a pressure
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One of the main issues arising during the rapid filling of a pipeline is the pressure transient which originates after the entrapped air has been expelled at the air release valve. Because of the difference in density between water and air, a pressure transient originates at the impact of the water column. Many authors have analyzed the problem, both from the theoretical and the experimental standpoint. Nevertheless, mainly vertical or horizontal pipelines have been analyzed, whereas in real field applications, the pipe profile is a sequence of ascending and descending pipes, with air release/vacuum valves at high points. To overcome lack of knowledge regarding this latter case, laboratory experiments were carried out to simulate the filling of an undulating pipeline, initially empty at atmospheric pressure. The pipe profile has a high point where an orifice is installed for air venting, so as to simulate the air release valve at intermediate high point of a supply pipeline. In the experiments, the diameter of the orifice and the opening degree of both upstream and downstream valves were varied, in order to analyze their effect on the pressure transient. The experiments were also carried out with a longer descending pipe, in order to assess the effects on the pressure surge of the air volume downstream of the orifice. Full article
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Open AccessArticle New Insights on the Simultaneous Removal by Adsorption on Organoclays of Humic Acid and Phenol
Water 2016, 8(1), 21; https://doi.org/10.3390/w8010021
Received: 23 August 2015 / Revised: 23 December 2015 / Accepted: 6 January 2016 / Published: 18 January 2016
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Abstract
The exploitation of thermal water as a heat source in houses and apartments (during winter) is a widely used alternative to natural gas. However, this type of water may contain organic contaminants, which must be removed before releasing the used water into rivers
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The exploitation of thermal water as a heat source in houses and apartments (during winter) is a widely used alternative to natural gas. However, this type of water may contain organic contaminants, which must be removed before releasing the used water into rivers and lakes. Because of the presence of a wide range of pollutants (including phenolic compounds and humates), efficient, cheap removal processes are needed. In order to demonstrate their capability in thermal water cleaning, clay minerals were applied for the removal of phenol and humic acid via adsorption. To determine the most efficient removal strategy for the aforementioned pollutants, the following parameters were investigated: the type of the clay mineral, the organophilization strategy (in situ or pre-organophilization), and the individual or simultaneous removability of the model pollutants. The current study revealed that the applied low cost, in situ prepared clay mineral adsorbents are applicable in the removal of pollutants from thermal water. Full article
(This article belongs to the Special Issue Groundwater Monitoring and Remediation)
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Open AccessArticle Effect of Plant Harvesting on the Performance of Constructed Wetlands during Summer
Water 2016, 8(1), 24; https://doi.org/10.3390/w8010024
Received: 24 November 2015 / Revised: 24 December 2015 / Accepted: 8 January 2016 / Published: 16 January 2016
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Abstract
Plants can remove pollutants through direct absorption and by providing habitats for microbes to stimulate their activities. The aboveground plant biomass is usually harvested to remove pollutants absorbed in plant tissues. However, the effect of plant harvesting during summer on the performance of
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Plants can remove pollutants through direct absorption and by providing habitats for microbes to stimulate their activities. The aboveground plant biomass is usually harvested to remove pollutants absorbed in plant tissues. However, the effect of plant harvesting during summer on the performance of constructed wetlands and microbial abundance is unclear. In this study, three types of microcosms were set up, including: cleared group (both shoots and roots were harvested), harvested group (only shoots were harvested) and unharvested group. The concentrations of ammonia nitrogen and chemical oxygen demand in the effluent of the harvested group were the lowest. The nitrogen mass balance showed that summer harvesting improved nitrogen absorbance by plants, which was 1.24-times higher than that in the unharvested group. Interestingly, the other losses were taken up by the highest amounts in the cleared group, which were 1.66- and 3.72-times higher than in the unharvested and harvested group, respectively. Quantitative polymerase chain reaction revealed that harvesting of shoots during summer increased the microbial abundance. Additionally, Proteobacteria was the dominant phylum among all bacteria according to pyrosequencing analysis. These results indicate that harvesting of shoots during summer has positive effects on pollutant removal and microbial abundance. Full article
(This article belongs to the Special Issue Constructed Wetlands Systems and Management)
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Open AccessArticle Potential Impacts of Climate Change on Water Resources in the Kunhar River Basin, Pakistan
Water 2016, 8(1), 23; https://doi.org/10.3390/w8010023
Received: 19 October 2015 / Revised: 31 December 2015 / Accepted: 4 January 2016 / Published: 16 January 2016
Cited by 10 | PDF Full-text (3909 KB) | HTML Full-text | XML Full-text
Abstract
Pakistan is one of the most highly water-stressed countries in the world and its water resources are greatly vulnerable to changing climatic conditions. The present study investigates the possible impacts of climate change on the water resources of the Kunhar River basin, Pakistan,
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Pakistan is one of the most highly water-stressed countries in the world and its water resources are greatly vulnerable to changing climatic conditions. The present study investigates the possible impacts of climate change on the water resources of the Kunhar River basin, Pakistan, under A2 and B2 scenarios of HadCM3, a global climate model. After successful development of the hydrological modeling system (HEC-HMS) for the basin, streamflow was simulated for three future periods (2011–2040, 2041–2070, and 2071–2099) and compared with the baseline period (1961–1990) to explore the changes in different flow indicators such as mean flow, low flow, median flow, high flow, flow duration curves, temporal shift in peaks, and temporal shifts in center-of-volume dates. From the results obtained, an overall increase in mean annual flow was projected in the basin under both A2 and B2 scenarios. However, while summer and autumn showed a noticeable increase in streamflow, spring and winter showed decreased streamflow. High and median flows were predicted to increase, but low flow was projected to decrease in the future under both scenarios. Flow duration curves showed that the probability of occurrence of flow is likely to be more in the future. It was also noted that peaks were predicted to shift from June to July in the future, and the center-of-volume date—the date at which half of the annual flow passes—will be delayed by about 9–17 days in the basin, under both A2 and B2 scenarios. On the whole, the Kunhar basin will face more floods and droughts in the future due to the projected increase in high flow and decrease in low flow and greater temporal and magnitudinal variations in peak flows. These results highlight how important it is to take cognizance of the impact of climate change on water resources in the basin and to formulate suitable policies for the proper utilization and management of these resources. Full article
(This article belongs to the Special Issue Water Resource Variability and Climate Change) Printed Edition available
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Open AccessArticle Roles of N:P Ratios on Trophic Structures and Ecological Stream Health in Lotic Ecosystems
Water 2016, 8(1), 22; https://doi.org/10.3390/w8010022
Received: 2 November 2015 / Revised: 23 December 2015 / Accepted: 7 January 2016 / Published: 16 January 2016
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Abstract
Little is known about the functions of N:P ratios in determining trophic structures and ecological health in lotic ecosystems, even though N:P ratios have been frequently used as a stoichiometric determinant in ambient water for trophic allocation of low-level organisms such as phytoplankton
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Little is known about the functions of N:P ratios in determining trophic structures and ecological health in lotic ecosystems, even though N:P ratios have been frequently used as a stoichiometric determinant in ambient water for trophic allocation of low-level organisms such as phytoplankton or zooplankton. In this study, nutrients (N, P) and sestonic chlorophyll (CHL) from 40 different streams in the Geum-River watershed were measured from 2008 to 2011. Fish compositions and stream health were also assessed, based on the multi-metric modeling of an index of biological integrity. Land use patterns in these watersheds were a key factor regulating nutrient contents and N:P ratios in ambient water, and also influenced empirical relationships between N:P ratios (or nutrients) and sestonic CHL. Land use patterns in forested, urban and wastewater treatment plant regions were associated with significant differences in stream N:P ratios, and the ratios were mainly determined by phosphorus. Sestonic CHL was significantly correlated with nutrient level (N, P); the ratios had a positive linear relationship with the proportion of omnivores, and a negative relationship with the proportion of insectivores. A similar trend in the N:P ratios was observed in indicator fishes such as N. koreanus and Z. platypus. Overall, the N:P ratio may be a good surrogate variable of ambient concentrations of N or P in assessing trophic linkage and diagnosing the ecological stream health in aquatic ecosystems. Full article
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Open AccessArticle A CN-Based Ensembled Hydrological Model for Enhanced Watershed Runoff Prediction
Water 2016, 8(1), 20; https://doi.org/10.3390/w8010020
Received: 2 October 2015 / Revised: 11 January 2016 / Accepted: 11 January 2016 / Published: 15 January 2016
Cited by 2 | PDF Full-text (4432 KB) | HTML Full-text | XML Full-text
Abstract
A major structural inconsistency of the traditional curve number (CN) model is its dependence on an unstable fixed initial abstraction, which normally results in sudden jumps in runoff estimation. Likewise, the lack of pre-storm soil moisture accounting (PSMA) procedure is another inherent limitation
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A major structural inconsistency of the traditional curve number (CN) model is its dependence on an unstable fixed initial abstraction, which normally results in sudden jumps in runoff estimation. Likewise, the lack of pre-storm soil moisture accounting (PSMA) procedure is another inherent limitation of the model. To circumvent those problems, we used a variable initial abstraction after ensembling the traditional CN model and a French four-parameter (GR4J) model to better quantify direct runoff from ungauged watersheds. To mimic the natural rainfall-runoff transformation at the watershed scale, our new parameterization designates intrinsic parameters and uses a simple structure. It exhibited more accurate and consistent results than earlier methods in evaluating data from 39 forest-dominated watersheds, both for small and large watersheds. In addition, based on different performance evaluation indicators, the runoff reproduction results show that the proposed model produced more consistent results for dry, normal, and wet watershed conditions than the other models used in this study. Full article
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Open AccessArticle Tracing Temporal Changes of Model Parameters in Rainfall-Runoff Modeling via a Real-Time Data Assimilation
Water 2016, 8(1), 19; https://doi.org/10.3390/w8010019
Received: 19 November 2015 / Revised: 31 December 2015 / Accepted: 4 January 2016 / Published: 11 January 2016
Cited by 2 | PDF Full-text (3455 KB) | HTML Full-text | XML Full-text
Abstract
Watershed characteristics such as patterns of land use and land cover (LULC), soil structure and river systems, have substantially changed due to natural and anthropogenic factors. To adapt hydrological models to the changing characteristics of watersheds, one of the feasible strategies is to
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Watershed characteristics such as patterns of land use and land cover (LULC), soil structure and river systems, have substantially changed due to natural and anthropogenic factors. To adapt hydrological models to the changing characteristics of watersheds, one of the feasible strategies is to explicitly estimate the changed parameters. However, few approaches have been dedicated to these non-stationary conditions. In this study, we employ an ensemble Kalman filter (EnKF) technique with a constrained parameter evolution scheme to trace the parameter changes. This technique is coupled to a rainfall-runoff model, i.e., the Xinanjiang (XAJ) model. In addition to a stationary condition, we designed three typical non-stationary conditions, including sudden, gradual and rotational changes with respect to two behavioral parameters of the XAJ. Synthetic experiments demonstrated that the EnKF-based method can trace the three types of parameter changes in real time. This method shows robust performance even for the scenarios of high-level uncertainties within rainfall input, modeling and observations, and it holds an implication for detecting changes in watershed characteristics. Coupling this method with a rainfall-runoff model is useful to adapt the model to non-stationary conditions, thereby improving flood simulations and predictions. Full article
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