Urban Recharge Research Articles

Assessment of Urban Land Use and Cover on Groundwater Recharge and Quality

This study focusses on a method for estimating the urban recharge and evaluating the ground water quality for drinking and irrigation purposes. The study was carried out in the Liverpool Local Government Area of New South Wales, Australia, and it included year-long monitoring of four boreholes for the water table depth and water quality. Average depth of water table was in the range of 1 to 4 m from the land surface. The pattern of variations in the water table depth (WTD) varied across the four boreholes. The WTD variations between borehole 2 (BH2) and borehole 3 (BH3) were similar, but significantly different variations were exhibited in BH1 and BH 4, with BH1 showing a quicker response to rainfall events. The presence of lake appears to have influenced the recharge pattern in the adjacent area as reflected in the WTD variations in BH3 and BH4. The recharge rates for BH3 and BH4 was about 2 to 5 times higher than those observed for BH1 and BH2, which are located at a relatively greater distance from the lake. This indicates that the presence of urban lakes can influence recharge rate in the area. Water quality analysis indicated higher salt and turbidity levels, which may be attributed to the local geology (the Wianamatta group) present in the study area and/or possible saltwater intrusion. This has implications for the treatment cost associated with the supply of the groundwater for drinking and irrigation purposes. Pearson’s analysis indicated a significant correlation between EC, TDS, Turbidity and pH. The turbidity of groundwater varied between 33 and 530 NTU, indicating that the turbidity may have been affected by the dissolution of salt deposits via colloidal particles. Significant variations in groundwater quality during rainy periods, also, indicated the existence of groundwater recharge in the study area. This study highlights the issues associated with the groundwater recharge and quality management in urban landscapes and provides a basis for further research.

Impact of urbanization on groundwater quality and recharge using hydrogeochemical and environmental tracers in the San Salvador Aquifer

Chemical and isotopic characteristics of the urban aquifer of San Salvador, drinking water (SAP) and wastewater systems (SAR), were evaluated in an area of 362 km2 to detect if leakages in both are recharging the aquifer and modifying its natural quality. An amount of 37 sampling sites that includes deep wells and springs, as well as two water import systems of the Metropolitan Area of San Salvador (AMSS) were sampled in 2007, 2009 and 2017. Samples were analyzed for major ions and stable isotopes of d18O and d2H. While the SAR was characterized by chemical tracers of Cl- and NO3-. Results show the existence of four water groups: Groups A (Ca-Mg-HCO3), B (Mg-Ca-HCO3) and D (Na-Ca-HCO3) have meteoric water as their main source of recharge, hence, they do not evidence urban influence in their quality; group C (Na-Ca-HCO3 and Na-Mg-HCO3) is derived from group A, flows under the AMSS and suggests three sources of recharge: Direct natural recharge due to precipitation along urban recharge from SAP and SAR leakages. An expensive “fictitious sustainability” could be perceived due to the quantitative contribution of the SAP recharge, which would be hiding the effects of the extractions and consequently the decrease of groundwater levels in the aquifer. Meanwhile, SAR recharge forewarn of a potential entry of pollutants into the aquifer that must be monitored and treated in a timely manner to avoid contamination. The study highlights the need of an integrated urban water resources management.

A Development of a ‘ArcSWAT’ Surface Runoff Model for Estimating Urban Precipitation Recharge

Groundwater recharge estimation is a fundamental part of groundwater resources management and may need to be estimated at a variety of spatial and temporal scales. Recharge is variable in time, responding to changes in land use and subsurface infrastructure as well as to climatic changes. Howevera, estimating recharge in urban environments is more complex than rural environments as it has many sources and pathways for recharge. Buildings, roads, land cover permeability, and other surface infrastructure combine with man-made drainage networks to influence recharge. Thus, this study is trying out an existing GIS-based system (ArcSWAT) to model and estimate urban recharge. The unconfined Triassic sandstone aquifer that underlies part of the city of Birmingham, United Kingdom (UK) was used as the study area for this project (occupies around 94.2km2 area). The results from this study show that SWAT model correlates better with 4RH (RMSE=17.78) as compared to UGif (RMSE=38.89) and 4ReH (RMSE=28.08). This is due to the reason that mains leakage factor has been included in 4RH and SWAT model. In summary, SWAT model produced a satisfactory result of urban precipitation recharge to the previous study that includes mains leakage factor during the modelling process.

Possibility on Contamination of Upper MUSI Ground Water for Flow Water at River End

The musi river historically provided farmers downstream of hyderabad with irrigation water for the cultivation of paddy for the duration of and after the monsoon rains. Through the construction of weirs, river water is retained in large and small reservoirs on the river from wherein it is diverted thru irrigation canals to village tanks and agricultural fields. This paper focuses on the sample description and corrective requirements after the survey samples at unique black points alongside musi. The presence heavy metals and microbiological pollutants have made the groundwater dangerous for consuming at diverse places in hyderabad. It has also proved that there is large issue of city groundwater recharge in this region. The internet urban recharge factor of groundwater in this region changed into anticipated to be about 567. 51 mm/a and natural recharge element turned into observed to be 52. 78 mm/a. The combination of tools carried out, the outcomes received and the recommendations provided in this have a look at will be helpful for neighborhood planners and selection makers to shield and restore the water assets on this location. The existing work also makes a speciality of the scope of infection by float water immersion at 2d part of musi river in ground as nicely agriculture. The consequences taken into consideration from 2017 june to may additionally 2019 for the actual identifications, the parameters are y18 and y19 for graphical enter.

Coupling groundwater GIS mapping and geovisualisation techniques in urban hydrogeomorphology: focus on methodology

The role of climate, geology, geomorphology, land use/cover, hydraulics and human activities are vital for the balanced and integrated assessment of water resources in urban areas. This approach addresses the key importance on ground field surveys at several scales, a representative hydrological inventory and an integrated groundwater mapping as useful tools to support urban groundwater systems conceptualisation. Lately, a new emphasis has arisen, addressing issues related to an integrated geovisualisation techniques and Geographical Information System (GIS) mapping studies on urban water supply systems, mainly in historical cities. Some key catchments in Porto urban area (NW Portugal) was selected to demonstrate this approach and to show the importance of groundwater GIS mapping for urban studies. The Porto city bedrock is dominated by an anisotropic and heterogeneous fissured media. An extensive field survey yielded data on hydroclimatology, hydrogeology, hydrogeomorphology, urban hydraulics and potential contamination sources. The Infiltration Potential Index in Urban Areas (IPI-Urban), Urban Recharge and Vulnerability Indexes was determined using GIS mapping techniques and hydrological inventory fieldwork. The integrated approach can be incorporated into an urban hydrological management system to support decision making on sustainable groundwater resources and in urban planning.

Reactive and Mixing Processes Governing Ammonium and Nitrate Coexistence in a Polluted Coastal Aquifer

A comprehensive hydrochemical, stable isotope and microbial analyses characterisation has been performed to evaluate the sources of groundwater, nitrogen pollution and degradation processes occurring in an industrial polluted coastal aquifer in the framework of a complex hydrodynamic system. The coexistence of ammonium and nitrate has been observed in almost all the investigated monitoring wells, reaching maximum values of 100 and 200 mg/L for both species. Chloride and potassium concentration coupled with groundwater stable isotopes data show the influence of local and urban recharge and the occurrence of seawater intrusion in areas near the coastline. δ15N–NH4+ values ranging between −4.9 and +14.9% suggest that different processes such as partial nitrification of ammonium, probably anammox activities and sorption, are occurring at the site. The isotope data for NH4+ also showed the existence of the remnant of an old fertilizer plume in the downgradient area. The nitrate isotope data ranging between +9 and +46% and +6 and +26% for δ15N–NO3− and δ18O–NO3−, respectively, suggest that nitrate content is attenuated by denitrification and probably annamox. The fast groundwater flow field is one of the reasons for the coexistence of NH4+ and NO3− in groundwater, since both compounds can penetrate the reducing zone of the aquifer. The influence of leakage of sewage pipelines on the aquifer cannot be discerned due to the complexities of the nitrogen attenuation processes, also influenced by pumping activities.

Recognition of the anthropogenic contribution to the input of fluoride in urban recharge

Fluoride is a common inorganic contaminant of geogenic origin around the world. Anthropogenic sources of fluoride could also contribute to increased fluoride concentrations in groundwater, although they have not been well-documented. This paper presents soil batches and unsaturated column experiments on fluoride-enriched recharge water percolating from a urine-polluted soil in an area where fluorosis is endemic. Results from the polluted soil collected near a main street in Addis Ababa (Ethiopia) are compared with an unpolluted soil collected in a garden inside the university campus, located 50 m from the polluted one. Soils were sampled at the end of the dry season and after the first intense rainfall at the beginning of the wet season. The objectives of the study were to evaluate the anthropogenic fluoride enrichment in urban recharge due to unmanaged human excretions along the streets and model recharge water fluxes and solutes leaching to evaluate the reactivity of dissolved species. Batch experiments found extremely high fluoride (42.1 ± 5.2 mg/kg) and urea (89.5 ± 8.1 mg/kg) concentrations in polluted soil before the rainy season. The fluoride concentration in the polluted soil was more than one order of magnitude higher than that recorded in the uncontaminated soil. This study proved that in areas where the population is subject to a large fluoride daily intake, recharge waters extremely enriched in fluoride can be leached from urine-contaminated soils in urban environments. The proposed methodology could be applied for a first screening for the anthropogenic sources of fluoride in urban recharge.

Impact of urbanization on groundwater recharge and urban water balance for the city of Hyderabad, India

Groundwater recharge processes in an urban area are different than in non-urban areas. There are various new components that must be considered in the case of urban groundwater recharge in addition to the natural recharge from precipitation. These various components are estimated in this study based on the water balance equation for the Hyderabad city of India. Initially, urban recharge components including leakages from water supply network and sewage networks were calculated. To estimate the natural recharge from precipitation, actual evapotranspiration and surface runoff were estimated using remote sensing and GIS techniques. Results indicated that the urban recharge component of groundwater was more than ten times greater than the natural recharge. The net urban recharge component of groundwater was estimated to be approximately 568mm yr-1 and the natural recharge component was observed to be 53mm yr-1. Water inflow and outflow components were also estimated to provide the complete scenario of the total urban water balance of Hyderabad. This analysis has provided the information regarding the extent and intensity of percolation of urban contaminants into the aquifer.

Groundwater Level Changes in Shallow Aquifer of Yogyakarta City, Indonesia: Distribution and Causes

The population in Yogyakarta City, Indonesia has increased since 1970, resulting in high groundwater utilization. This normally results in a decline of groundwater level in shallow aquifer beneath the city. However, expansion of the city and urbanization effects can also have the opposite effect and lead to a rise of groundwater levels due to urban recharge. This study investigates groundwater level changes in Yogyakarta City during a time period of 30 years between 1985 and 2015. Collected data in this research are groundwater level, rainfall, population density, sewer system, and land use. Overlaying various spatial information reveals a pattern of groundwater level rise in some areas of the city by 0–12 m, whilst in other areas a decline of 0–9 m is discovered. Rising groundwater levels are mainly found in areas moderate to high population density where sewer system networks have been installed. The rising of groundwater levels is this expected to be caused by urban recharge and sewers leakage.

Sustainable cities and the groundwater governance challenge

With over half the world’s population now living in towns and cities, serious questions are being asked about the sustainability of urban water supplies. Groundwater is a particular concern as it represents over 95 % of the world’s available fresh water reserves and supplies over 1.5 billion city dwellers with water essential for their drinking and sanitation needs. Within 20 years, the global population is projected to rise from 7 billion to 8 billion with this entire growth accommodated in urban areas. Much of the additional water required will be sought from groundwater due to the generally modest cost of waterwells and the close, “well’s length” proximity of the resource. Fortunately, significant progress has been made in the science of urban groundwater during the past 25 years, most notably with respect to the nature of urban recharge and components of the urban water balance, contaminant source characterisation, recharge management and methods of assessing aquifer vulnerability. There have also been major advances in the development and use of advanced ground and surface water modelling tools, some of which are linked with GIS and urban databanks to provide unprecedented support for resource management decision making. What is missing are appropriate systems of urban water governance that are essential for effective and responsible groundwater resource management. Despite the growing popularity of “integrated water resource management” models that promote urban water management in a comprehensive, holistic, way, it is not clear that such techniques adequately incorporate the unique storage and flow attributes of groundwater, behaviours that merit special management considerations. Today, a significantly increased awareness for the valuable role of groundwater in the urban water cycle is beginning to raise its profile at the political level. Improved groundwater governance with the full involvement of all stakeholders in the decision-making process is now recognised as the key to resolve sustainability concerns over water in the world’s rapidly growing cities.

Slowflow fingerprints of urban hydrology

Summary Urban streamflow is commonly characterized by increased peak discharges and runoff volumes. Slowflow integrates altered storage and transit times affecting urban recharge and drainage, resulting in a highly variable indeterminate urban slowflow response. This study introduces the use of multiple baseflow metrics to characterize and interpret the dominant processes driving urban slowflow response. Slowflow characteristics derived from USGS streamflow records are used to quantify the patterns of hydrologic alteration across the rural-to-urban landuse gradient in the Piedmont watersheds of the Baltimore Ecosystem Study (BES), an NSF Urban Long Term Ecological Research (LTER) site in the Baltimore Metropolitan area. We interpret multimetric slowflow response from a top-down perspective, learning from data, in order to draw dominant process inferences from observed slowflow. When characterized by a single slowflow metric such as the baseflow index, urban slowflow response can exhibit equifinality and is not reliably predicted a priori. Multimetric analysis quantifies distinct differences in urban slowflow response, framing testable hypotheses and refined experimental designs to elucidate the dominant processes driving urban slowflow. Multimetric fingerprinting offers a consistent framework for interpreting urban slowflow response, constrained by the equifinality of single slowflow metrics and the inherent limitations on process inferences that can be drawn from gauged streamflow alone. Heterogeneity of observed slowflow belies the simple paradigm of a single consistent type of urban slowflow response. In contrast, we suggest a conceptual typology of urban slowflow response, framing a conceptual mixing model of dominant process endpoints that shape the slowflow fingerprints of urban hydrology.

Urban recharge beneath low impact development and effects of climate variability and change

[1] Understanding low impact development (LID) planning and best management practices (BMPs) effects on recharge is important because of the increasing use of LID BMPs to reduce storm water runoff and improve surface-water quality. LID BMPs are microscale, decentralized management techniques such as vegetated systems, pervious pavement, and infiltration trenches to capture, reduce, filter, and slow storm water runoff. Some BMPs may enhance recharge, which has often been considered a secondary management benefit. Here we report results of a field and HYDRUS-2D modeling study in San Francisco, California, USA to quantify urban recharge rates, volumes, and efficiency beneath a LID BMP infiltration trench and irrigated lawn considering historical El Nino/Southern Oscillation (ENSO) variability and future climate change using simulated precipitation from the Geophysical Fluid Dynamic Laboratory (GFDL) A1F1 climate scenario. We find that in situ and modeling methods are complementary, particularly for simulating historical and future recharge scenarios, and the in situ data are critical for accurately estimating recharge under current conditions. Observed (2011–2012) and future (2099–2100) recharge rates beneath the infiltration trench (1750–3710 mm yr−1) were an order of magnitude greater than beneath the irrigated lawn (130–730 mm yr−1). Beneath the infiltration trench, recharge rates ranged from 1390 to 5840 mm yr−1 and averaged 3410 mm yr−1 for El Nino years (1954–2012) and from 1540 to 3330 mm yr−1 and averaged 2430 mm yr−1 for La Nina years. We demonstrate a clear benefit for recharge and local groundwater resources using LID BMPs.

Recharge assessment in an urban area: a case study of La Plata, Argentina

Leakage from water mains, storm drainage and sewer systems in urban areas constitutes a source of recharge that is difficult to identify and quantify at a regional scale. The objective of this work is to apply a methodology that would make it possible to evaluate urban recharge at a regional scale, taking as a case study the city of La Plata (Argentina). In the study area, population growth and an increase in water demand has caused the intensive exploitation of groundwater with resulting alteration in groundwater flow. The methodology used was developed on the basis of a water balance and the simulation of the temporal evolution of the cones of depression and the volumes of water extracted from the aquifer. The method consists of adjusting the piezometry resulting from the numerical modelling to the measured piezometry, by means of the variation of the recharge parameter in the urban area. The results obtained make it possible to identify and quantify urban recharge, which in this case represents a volume of water similar to the recharge from precipitation.

Estimating Urban-Induced Artificial Recharge: A Case Study for Austin, TX

Urbanization alters the character and state of the land surface. Urban-induced anthropogenic recharge sources that include leaky utility lines, storm sewer systems, and storm-water catchments, as well as over-irrigation of lawns, parks, and golf courses, can be significant. However, data may be sparse and quantification difficult. A case study for Austin, TX, uses commonly available data to estimate recharge from leaky utility lines and irrigation return flows. The estimates indicate that these sources accounted for at least 5 percent of the total recharge between 1999 and 2009 and that on a monthly basis these contributions can vary from <1 percent to nearly 100 percent of the total recharge. Irrigation return flow was the most significant contributor in summer seasons; however, leakage from utility lines provided more total recharge. Urban recharge contributions were comparable to the mid-size watershed contributions over the 10-year period. These estimates are conservative and should be reevaluated as urbanization continues and as new data become available. Outcomes are relevant for habitat conservation, drought response planning, and urban groundwater management. Urban recharge can be important for buffering seasonal fluctuations during periods of low precipitation and springflow.

Impacts of urbanization on the groundwater resources in Shahrood, Northeastern Iran: Comparison with other Iranian and Asian cities

Urbanization may lead to the contamination of groundwater and/or it may alter the hydrogeological regime. Shahrood is a medium size city in northeastern Iran, underlain by an alluvial aquifer. Analysis of 45 samples collected from the Shahrood Plain’s aquifer in 2003 and 2005 revealed that: (1) Shahrood’s wastewater disposal wells and deep cesspits have led to the nitrate pollution of groundwater (up to 140 mg/L NO 3–NO 3); (2) urban recharge has lowered the groundwater temperature and pH and (3) urbanization has possibly resulted in the incomplete interaction between various flow compartments of the aquifer. In four other Iranian cities, Gorgan, Kerman, Zahedan and Mashad, urbanization has led to water quality deterioration, alarming rise of groundwater levels endangering foundations of the buildings as well as collapse of ‘qanat’s galleries. The maximum concentration of nitrate (MCN) in groundwater in all these cities has been compared with the ratio of population/rainfall in each city. A similar exercise has been carried out for Asian megacities. These show that MCN in an urban aquifer is directly controlled by population and average annual rainfall. This has serious implications for the management of urban groundwater resources and suggests that the current world population growth rate and the likely reduction in the atmospheric precipitation induced by global warming will further deteriorate the quality of such resources.

Estimation of sewer leakage to urban groundwater using depth‐specific hydrochemistry

AbstractThe contribution of sewer leakage to urban groundwater recharge remains poorly characterised. There has been a tendency to focus on estimating leakage from pipe network characteristics rather than its impact on the receiving environment. Indeed, pipeline leakage simulation models are frequently used to analyse sewage systems and optimise maintenance efforts. Here a mass balance approach employing groundwater geochemistry is presented to estimate sewer leakage rates; this is done using depth‐specific groundwater quality measurements from multilevel monitoring piezometers, specially installed in the Sherwood Sandstone aquifer underlying Doncaster (UK). The results show that leakage rates from the foul sewage system are up to 10% of flow per annum (30–40% of urban recharge) and highlight the utility of groundwater quality monitoring (in particular depth‐specific sampling) as an alternative means to assess sewage ingress to urban groundwater.

Tracing sources of carbon in urban groundwater using δ13CTDIC ratios

Total dissolved inorganic carbon (TDIC) and its stable isotope ratio δ13CTDIC are used to trace the evolution of the carbon system of groundwater in three UK Permo-Triassic sandstone aquifers. Samples were collected from multilevel piezometers, open boreholes and sewer sampling points in the British Midlands (Nottingham, Birmingham and Doncaster) to evaluate both local and regional variations in δ13CTDIC. δ13C samples of matrix and pore water have also been analysed in each aquifer to further constrain the interpretations. Combining δ13CTDIC ratios with measurements of TDIC and pH clearly distinguishes the principal processes underlying the geochemical evolution of groundwater in Triassic sandstone aquifers, where processes can be both natural (e.g. carbonate dissolution) and anthropogenic (sewer-derived recharge). The paper shows that δ13CTDIC resolves ambiguities that arise from the interpretation of TDIC and pH measurements in isolation. Field measurements demonstrate that, under natural conditions, the carbonate system evolves similarly in each aquifer. An open-system evolution during recharge largely saturates the groundwater with carbonate depending upon its availability in the sandstone matrix. The contribution of sewer exfiltration to urban recharge is readily distinguished by lower pH and higher TDIC values without significant changes in δ13CTDIC.

Hydrochemical evidence of the depth of penetration of anthropogenic recharge in sandstone aquifers underlying two mature cities in the UK

Pollution of urban groundwater is routinely reported but the profile of contamination with depth in urban aquifers is rarely resolved. This limits understanding of the depth of penetration of urban recharge and contaminants, and use of urban groundwater. Penetration of anthropogenic solutes (major ions, trace metals) in Permo-Triassic sandstone aquifers underlying two mature conurbations in the UK was investigated through depth-specific, groundwater sampling of dedicated multilevel piezometers. Identification of solute origin and biogeochemical processes (e.g. denitrification, mineral dissolution) was aided by use of stable isotope ratios ( 34S/ 32S, 18O/ 16O, 15N/ 14N, 13C/ 12C) and chemical speciation modelling (PHREEQC). Depth profiles of aquifer hydrochemistry reveal penetration of anthropogenic solutes to depths of between 30 and 47 m below ground in the unconfined sandstone and confirm the contributions of faecal and industrial effluents to urban recharge. They also highlight the complexity of solute loading and difficulty resolving solute origin from the range of potential sources in urban groundwater. Faecally-derived NO 3 is the most pervasive contaminant exceeding drinking-water quality guidelines and is associated with elevated concentrations of B and SO 4. Elevated concentrations of Li, B, Cr and Co are observed at depth in groundwater contaminated by long-term industrial land use (metalworking). Observed penetration of anthropogenic solutes in the unconfined sandstone is consistent with post-development recharge of urban groundwater (residence times <230 a) indicated by flow modelling, and suggests tentatively that urban abstraction to depths of up to 50 m below ground in the unconfined Permo-Triassic sandstone is required to scavenge contaminated groundwater.

A groundwater recharge methodology for Water Framework Directive initial characterization in Scotland

Synopsis Estimation of recharge to groundwater is an important component in the characterization of groundwater bodies for the Water Framework Directive (WFD). The time scale allowed for the WFD initial characterization required a pragmatic methodology for efficient assessment of recharge to each delineated groundwater body. An assessment methodology was developed through a project funded by the Scotland and Northern Ireland Forum for Environmental Research, although it has application throughout the UK. Few recharge calculations have previously been attempted in Scotland. The environmental influences on recharge processes differ from much of the rest of the UK and the ability of the groundwater body to accept recharge is a key criteria. The method proposed is based on a water budget approach which estimates direct and indirect recharge flow components. It includes estimation of effective rainfall, actual evapotranspiration, surface run-off and interflow in addition to the potential impacts of snow-melt, bypass flows, urban recharge and surface water leakage where appropriate. This is calculated on a daily or monthly time step with the use of a spreadsheet software tool. The degree of uncertainty in the recharge estimation increases with the scarcity of data available to the groundwater body. Many recharge estimations in Scotland will rely on national-scale mapping of climatic, land use, soil and aquifer properties. It is important that the confidence in the estimation is balanced against the perceived risk of stress to the groundwater body. Validation of the recharge calculations is ongoing and the assessment of bypass flow and interflow has been determined as critical to the accuracy of the calculation.

Identifying and quantifying urban recharge: a review

The sources of and pathways for groundwater recharge in urban areas are more numerous and complex than in rural environments. Buildings, roads, and other surface infrastructure combine with man-made drainage networks to change the pathways for precipitation. Some direct recharge is lost, but additional recharge can occur from storm drainage systems. Large amounts of water are imported into most cities for supply, distributed through underground pipes, and collected again in sewers or septic tanks. The leaks from these pipe networks often provide substantial recharge. Sources of recharge in urban areas are identified through piezometry, chemical signatures, and water balances. All three approaches have problems. Recharge is quantified either by individual components (direct recharge, water-mains leakage, septic tanks, etc.) or holistically. Working with individual components requires large amounts of data, much of which is uncertain and is likely to lead to large uncertainties in the final result. Recommended holistic approaches include the use of groundwater modelling and solute balances, where various types of data are integrated. Urban recharge remains an under-researched topic, with few high-quality case studies reported in the literature.