Search Results (10)

In early 2018, Cape Town, South Africa, experienced severe water shortages during the worst drought in nearly a century (2015–2017), underscoring the need to diversify water resources, including groundwater. This study evaluated infiltration rates and hydraulic properties of three representative stormwater ponds in the Zeekoe Catchment, Cape Town, to assess their feasibility as recharge basins for transferring detained stormwater runoff into the underlying aquifer. Field infiltration data were analysed to estimate hydraulic properties, while laboratory permeability tests and material classification on 36 soil samples provided inputs for numerical modelling using HYDRUS 2-D software. Simulations estimated recharge rates and indicated wetting front movement from pond surfaces to the water table (~5.5 m depth) ranged between 15 and 140 h. The results revealed field hydraulic conductivity values of 0.3 to 19.9 cm/h, with laboratory estimates up to 103% higher due to controlled conditions. Simulated infiltration rates were 67–182% higher than field measurements, attributed to idealised assumptions. Despite these variations, ponds in the central catchment exhibited the highest infiltration rates, indicating suitability for artificial recharge. Explicit recognition of pond-specific infiltration variability significantly contributes to informed urban water security planning, enabling targeted interventions to optimise groundwater recharge initiatives. Full article

Rain gardens are increasingly being used to control stormwater. Infiltration is a key component of volume control. Thus, determining the infiltration rate or field saturated hydraulic conductivity (K_sat) of rain gardens is critical to their continued successful operation. Designers and inspectors of rain gardens need to rapidly and efficiently determine the field K_sat. Prior research has found that single-ring infiltrometers (Princeton Hydro, Trenton, NJ, USA) can reliably be used to determine the infiltration rates of soils. The question often posed by designers and inspectors is “how many spot-infiltration tests are needed to sufficiently characterize the infiltration capacity of a rain garden?” Five rain gardens, varying in size from 62 to 429 m², were analyzed for this study. Three different spot infiltration methods were used: single-ring (Princeton Hydro, Trenton, NJ, USA) (least sophisticated and expensive), modified Philip–Dunne (Villanova University, Villanova, PA, USA), and SATURO (METER Group, Pullman, WA, USA) (most sophisticated and expensive). These rain gardens also had been instrumented to capture the recession rates during either natural or artificial ponding events. The linear portion of the recession curve obtained during ponding events was used to provide the rain-garden-wide K_sat. It was found that the geometric mean of six spot infiltration tests provided a reliable K_sat value similar to that found by the recession rate, which best represents the value of K_sat for the entire rain garden. This indicates that an inspector can reliably determine the infiltration capacity of a rain garden in less than a day. Full article

Urbanization and climate change exacerbate groundwater overexploitation and urban flooding. The infiltration basin plays a significant role in protecting groundwater resources because it is a prevalent technology of managed aquifer recharge. It could also be utilized as a retention pond to mitigate city waterlogging. The goal of this study was to explore the offsets of artificial recharge on the extra runoff induced by urbanization and extreme storms via infiltration basins. To achieve this objective, a lumped infiltration basin module was developed and integrated into a semi-distributed hydrologic model. Then, the enhanced model was applied to an agriculture watershed with urban areas. Finally, the functionalities of the infiltration basins were evaluated under the scenarios of the predicted urbanization and extreme storms. The results demonstrated the capability of the infiltration basins to influence both artificial recharge and flood mitigation. To mitigate floods, especially peak flows, larger areas are needed for infiltration basins than for artificial recharge purposes only. Based on different demands, the intermittent regulation of infiltration basins according to different hydrologic periods is recommended. The offsets of artificial recharge on the extra surface runoff provide insight into the comprehensive preservation and management of surface water resources and groundwater resources. Full article

Groundwater is critical to the socioeconomic development of any region. Infiltration of surface water into the ground is influenced by a variety of factors such as soil pores, folds, fractures, faults, and joints, all of which contribute to groundwater recharge. Groundwater is an important source of freshwater in the drought-prone Pudukkottai district of Tamil Nadu, India. Therefore, the search for groundwater potential zones (GWPZs) is critical. The present study focuses on the investigation of potential groundwater zones using geospatial techniques. Geology, land use and land cover, geomorphology, soil, drainage density, lineament, and groundwater levels were obtained from state and non-state associations. ArcGIS version 10.8 was used to create all thematic layers and classified grids. The intensive use of groundwater in arid and semiarid regions is becoming a problem for the public to meet their freshwater needs. The condition of arid and semi-arid regions due to intensive groundwater extraction has become one of the most important environmental problems for the public. In this study, a powerful groundwater potential mapping technique was developed using integrated remote sensing data from GIS-AHP. Using AHP techniques, thematic layers for geology, geomorphology, and soil followed by drainage, drainage density and lineament, lineament density, slope, water level, and lithological parameters were created, classified, weighted, and integrated into a GIS environment. According to the results of the study, it is estimated that 14% of the groundwater potential in the study area is good, 49% is moderate and 36% is poor. A groundwater level map was used to verify the groundwater potential. In addition, the model was validated with a single-layer sensitivity analysis, which showed that geology was the most influential layer and water level was the least influential thematic layer. The low-potential areas identified on the groundwater potential map can be used for further study to identify ideal locations for artificial recharge. In low potential areas, the groundwater potential map can be used to find ideal locations for artificial recharge. The water table in the area must be raised by artificial recharge structures such as infiltration basins, recharge pits, and agricultural ponds. Artificial recharge structures such as infiltration basins, recharge pits, and agricultural ponds can be used for groundwater development in the low potential zones. The GWPZ map was successfully validated with three proxy data, such as the number of wells, groundwater level, and well density, obtained from well inventory information. The results of this study will improve our understanding of the geographic analysis of groundwater potential and help policy makers in this drought-prone area to create more sustainable water supply systems. Full article

The improvement of rural living standards in developing countries and the continuous upgrading of the rural industrial economy have prompted the diversification of rural areas and residential forms. Thus, an integrated rural sewage treatment process has gradually become the mainstream technology for rural sewage treatment. Numerous studies have reported the effects of ecological wastewater treatment. Meanwhile, the relevant process technologies, evaluations, and operating models of the integrated rural sewage treatment process have yet to be thoroughly summarized. This review aims to fill these gaps. First, the applicability of artificial wetland, soil infiltration, stabilization pond, and integrated rural sewage treatment process technology in rural sewage treatment are outlined and compared. Second, the process flow, technical characteristics, and economic indicators of typical integrated sewage treatment processes (i.e., Anoxic/Oxic (A/O) process, Membrane Bio-Reactor (MBR) process, biological contact oxidation process, Sequencing Batch Reactor Activated Sludge (SBR) process) are introduced. The engineering application effects of the integrated rural sewage treatment process in different countries are also described. Third, the practical and effective evaluation methods of the integrated rural sewage treatment process are introduced. Bearing in mind the current operation and maintenance management modes of the integrated rural sewage treatment process in developed and developing countries, combined with the national conditions of developing countries, the prospect section provides development proposals for further optimization and improvement of the integrated rural sewage treatment process in developing countries. Full article

The content of pharmaceuticals in natural waters is steadily increasing. Especially nonsteroidal anti-inflammatory drugs (NSAIDs) are often detected in natural waters due to their widespread use. This group of compounds includes commonly used representatives, such as paracetamol and ketoprofen. The quality of natural waters determines the processes applied for the treatment of drinking water. The methods used in order to remove pharmaceuticals from treated water include adsorption and biologically active filtration. Both processes also occur during artificial infiltration (forced flow of intake surface water through the ground to the collecting wells) at surface water intakes. The processes, which occur in the soil, change the water quality characteristics to a great extent. The goal of the study was to evaluate the removal efficiency of paracetamol and ketoprofen in the process of artificial infiltration used as a pre-treatment of surface water. The studies were conducted at a field experimental installation located at the technical artificial infiltration intake. The experimental installation consisted of three metering wells (piezometers) which were located on the way between the bank of the infiltration pond and the collecting well. The collected water samples allowed to evaluate the change of selected NSAIDs concentrations during the passage of water through the ground. The analysis procedure included solid phase extraction (SPE) and high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Removal of the studied NSAIDs in the infiltration process occurred with variable effectiveness throughout the year. Paracetamol was removed with annual efficiency equal to 42%, although no significant removal of ketoprofen was observed. Full article

This paper aims to propose methods to mitigate the risks of flash flood events in arid rural communities with poor infrastructure. A flash flood management case study was conducted at Afouna Village in Egypt, which is characterized by an arid climate and faced a devasting flash flood in 2015. First, the flash flood was modelled and it was found that it corresponds to a 100 year return period flood that led to an almost 13 million m³ total runoff volume. A structural protection approach, using an artificial infiltration pond, was applied to mitigate the flooding risks through water harvesting and recharging the groundwater of the Moghra aquifer. In this study, a novel approach was proposed, which is substituting the low permeability silty sand (2.0 × 10⁻⁴ m/s) in the pond area with a high permeability one (9.6 × 10⁻³ m/s), which will enhance water harvesting and reduce direct evaporation. Modern techniques of hydrological modelling were utilized in order to achieve the optimal use, and harvesting, of flash flood water. Full article

Artificial groundwater recharge is commonly used for drinking water supply. The resulting water quality is highly dependent on the raw water quality. In many cases, pretreatment is required. Pretreatment improves the drinking water quality, although how and to what extent it affects the subsequent pond water quality and infiltration process, is still unknown. We evaluated two treatment systems by applying different pretreatment methods for raw water from a eutrophic and temperate lake. An artificial recharge pond was divided into two parts, where one received raw water, only filtered through a microscreen with 500 µm pores (control treatment), while the other part received pretreated lake water using chemical flocculation with polyaluminum chloride (PACl) combined with sand filtration, i.e., continuous contact filtration (contact filter treatment). Water quality factors such as cyanobacterial biomass, microcystin, as well as organic matter and nutrients were measured in both treatment processes. Microcystin condition was screened by an immunoassay and a few selected samples were examined by ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) which is a chemistry technique that combines the physical separation capabilities of liquid chromatography with the mass analysis capabilities of mass spectrometry. Results showed that cyanobacterial biomass and microcystin after the contact filter treatment were significantly different from the control treatment and also significantly different in the pond water. In addition, with contact filter treatment, total phosphorus (TP) and organic matter removal were significantly improved in the end water, TP was reduced by 96% (<20 µg/L) and the total organic carbon (TOC) was reduced by 66% instead of 55% (TOC content around 2.1 mg/L instead of 3.0 mg/L). This full-scale onsite experiment demonstrated effective pretreatment would benefit a more stable water quality system, with less variance and lower microcystin risk. From a broader drinking water management perspective, the presented method is promising for reducing cyanotoxin risk, as well as TP and TOC, which are all predicted to increase with global warming and extreme weather. Full article

Floods are of great concern as the global climate changes, and investigations of flood water infiltration and groundwater recharge are important for water resource management worldwide, especially under conditions of global climate changes. However, information on the relationship between the flood water and groundwater recharge is limited. The objective of this study was to determine the relationship between the flood water depth and the height of groundwater rise using lysimeters and numerical modeling in the floodplain of the Tarim River in northwestern China. The experimental results suggested that the rise in height of the groundwater table was closely related to the flood water ponding depth, and the groundwater depth decreased quickly after flooding due to the high infiltration rate of water originating at the Tarim River. The water table falling velocity was significantly less than the water table rising velocity. If the initial groundwater table was deeper, the variation in the water table rise depth was smaller and the water table falling velocity was slower. The numerical simulation results showed good agreement with the observed data, with a determination coefficient (R²) of 0.87 and a root mean square error (RMSE) of 63.91 cm. A good relationship (R² = 0.789) between the initial groundwater table depth (H₀), initial soil water content (W₀), flood water depth (h), and height of the water table rise (H) was established. Considering that natural and artificial flood frequencies are related to flood time interval (dt), a relationship (R² = 0.892) was developed between them. These results can enhance the understanding of flood recharge characteristics in the floodplains of inland rivers. Full article

Conservation agriculture is often presented as being ‘climate smart’ due to anticipated increases in soil moisture. The extent of enhanced water availability in farmers’ fields is, however, poorly documented. This paper presents five data sets describing soil moisture in fields of small-scale conservation and conventional farmers in the Agro-ecological Zone IIa, Zambia. The data include (1) soil cover; (2) time required for visible soil surface saturation, ponding and initial runoff under artificial rainfall; (3) saturated water infiltration rates; (4) weekly soil moisture at six soil depths for two entire rain seasons; and (5) weekly rainfall in each field. Measurements were done for 15 pairs of comparable fields under conservation and conventional agriculture. Pairwise analysis showed significantly shorter time for surface saturation, ponding, and runoff in conservation fields compared to conventional fields. Saturated infiltration rates in riplines and basins of conservation fields were similar to rates in ploughed/hoed fields. Infiltration rates between riplines and between basins were 31–37% lower than those in ploughed/hoed fields. Soil moisture in riplines and basins of conservation fields was higher by an average factor of 1.08 down to 40 cm soil depth, whereas it was lower by an average factor of 0.89 between plant rows compared to fields under conventional tillage. Based on 34,000 soil moisture measurements from 0 to 60 cm depth over two seasons, soils in conservation fields contained a weighted average of 18.2% (vol.) water compared to 19.9% (vol.) in conventional fields (p < 0.05). The results indicate that small-scale adopters of conservation agriculture are less ‘climate smart’ than conventional farmers in terms of water infiltration and soil moisture. Full article