Your search found 33 records
1 Loague, K. 2010. Rainfall-runoff modelling. Wallingford, UK: International Association of Hydrological Sciences (IAHS). 506p. (IAHS Benchmark Papers in Hydrology 4)
Rainfall-runoff relationships ; Models ; Flooding ; Catchment areas ; Stream flow ; Hydrology ; Hydrography ; Groundwater flow ; Flow discharge ; Surface runoff ; Infiltration ; Sloping lands / Australia / USA / Washington / Reynolds Creek Watershed / Idaho
(Location: IWMI HQ Call no: 333.91 G000 LOA Record No: H043500)
(0.36 MB)
2 Katic, Pamela; Grafton, R. Q. 2012. Economic and spatial modelling of groundwater extraction. Hydrogeology Journal, 20(5):831-834. [doi: https://doi.org/10.1007/s10040-011-0817-z]
(Location: IWMI HQ Call no: e-copy only Record No: H044697)
(0.07 MB)
3 Chinnasamy, P.; Hubbart, J. A. 2014. Measuring and modeling shallow groundwater flow between a semi-karst border stream and Ozark forested riparian zone in the Central USA. Journal of Scientific Research and Reports, 3(6):844-865.
Groundwater flow ; Flow discharge ; Ecosystems ; Forests ; Riparian zones ; Hydrology ; Models ; Soil hydraulic properties ; Stream flow / USA / Missouri
(Location: IWMI HQ Call no: e-copy only Record No: H046360)
http://www.sciencedomain.org/download.php?f=Chinnasamy362013JSRR7711_1.pdf&aid=3574
https://vlibrary.iwmi.org/pdf/H046360.pdf
https://vlibrary.iwmi.org/pdf/H046360.pdf
(0.52 MB)
Aims: Quantitative information is limited pertaining to riparian forest and stream shallow groundwater interactions particularly in karst hydro-ecosystems. Study Design, Place and Duration: Spatiotemporal variability of shallow groundwater flow was monitored along two stream reaches in a riparian Ozark border forest of central Missouri, United States. Each reach was equipped with twelve piezometers and two stream-gauging stations during the 2011 water year (WY). Methodology: High-resolution (i.e. 15 minute) time-series data were analyzed indicating average groundwater flow per unit stream length was -3 x 10-5 m3 s-1 m-1 (losing stream) for the entire study reach (total reach length = 830m) during the 2011 WY. The HYDRUS – 1D groundwater flow model was forced with observed data and outputs were assessed to improve model end user confidence in karst hydrogeologic systems. Results and Discussion: Results indicate rapid groundwater response to rainfall events within two to 24 hours nine meters from the stream. Analyses indicated average stream flow loss of 28% and 7% total volume to groundwater during winter and spring seasons, respectively. During the dry season (June-September), the stream was gaining 95% of the time. During the wet season (March-June), the stream was losing 70% of the time. Based on established assessment criteria, shallow groundwater modeling performance with HYDRUS – 1D was deemed very good (NS = 0.95, r2 = 0.99, RMSE = 2.38 cm and MD =1.3 cm). Conclusion: Results supply greatly needed baseline information necessary for improved understanding of riparian forest management and shallow groundwater transport and storage processes in semi-karst forest ecosystems.
4 Elango, L. (Ed.) 2005. Numerical simulation of groundwater flow and solute transport. New Delhi, India: Allied Publishers. 245p.
Groundwater management ; Groundwater flow ; Mathematical models ; Hydrogeology ; Waterlogging ; Groundwater pollution ; Contamination ; Remote sensing ; Rivers ; Case studies / India / Orissa / Hirakud / Palar River / Hyderabad / Andhra Pradesh / Patancheru / Medak District / Karnataka
(Location: IWMI HQ Call no: 553.79 G635 ELA Record No: H046629)
(0.31 MB)
5 Elango, L.; Jayakumar, R. (Eds.) 2001. Modelling in hydrogeology. New Delhi, India: Allied Publishers. 259p.
Hydrogeology ; Models ; Groundwater flow ; Aquifers ; Artificial recharge ; Watersheds ; River basin management ; Mathematical models ; Salt water intrusion ; Soil fertility ; Chlorides ; Nitrogen ; Hydrocarbons ; Porous media / India / Australia / South America / Gujarat / Chennai / Tamil Nadu / Mahi Right Bank Canal / Lower Murray Region / Kallar Watershed / Lower Palar River Basin / Guarani Aquifer
(Location: IWMI HQ Call no: 551.48011 G000 ELA Record No: H046634)
(0.52 MB)
6 Chinnasamy, Pennan; Hubbart, J. A. 2014. Potential of MODFLOW to model hydrological interactions in a Semikarst floodplain of the Ozark Border Forest in the Central United States. Earth Interactions, 18(20):1-24. [doi: https://doi.org/10.1175/EI-D-14-0015.1]
Hydrology ; Models ; Surface water ; Groundwater flow ; Nitrates ; Precipitation ; Floodplains ; Stream flow ; Forests ; Riparian zones / Central USA / Missouri / Ozark Forest
(Location: IWMI HQ Call no: e-copy only Record No: H046708)
http://journals.ametsoc.org/doi/pdf/10.1175/EI-D-14-0015.1
https://vlibrary.iwmi.org/pdf/H046708.pdf
https://vlibrary.iwmi.org/pdf/H046708.pdf
(1.81 MB) (1.81 MB)
Riparian shallow groundwater and nutrient movement is important for aquatic and forest ecosystem health. Understanding stream water (SW)–shallow groundwater (GW) interactions is necessary for proper management of floodplain biodiversity, but it is particularly confounding in underrepresented semikarst hydrogeological systems. The Modular Three-Dimensional Finite-Difference Ground-Water Flow Model (MODFLOW) was used to simulate shallow groundwater flow and nutrient transport processes in a second-growth Ozark border forest for the 2011 water year. MODFLOW provided approximations of hydrologic head that were statistically comparable to observed data (Nash–Sutcliffe = 0.47, r2 = 0.77, root-mean-square error = 0.61 cm, and mean difference = 0.46 cm). Average annual flow estimates indicated that 82% of the reach length was a losing stream, while the remaining 18% was gaining. The reach lost more water to the GW during summer (2405 m3 day-1) relative to fall (2184 m3 day-1), spring (2102 m3 day-1), and winter (1549 m3 day-1) seasons. Model results showed that the shallow aquifer had the highest nitrate loading during the winter season (707 kg day-1). A Particle-Tracking Model for MODFLOW (MODPATH) revealed significant spatial variations between piezometer sites (p = 0.089) in subsurface flow path and travel time, ranging from 213 m and 3.6 yr to 197 m and 11.6 yr. The current study approach is novel with regard to the use of transient flow conditions (as opposed to steady state conditions) in underrepresented semikarst geological systems of the U.S. Midwest. This study emphasizes the significance of semikarst geology in regulating SW–GW hydrologic and nutrient interactions and provides baseline information and modeling predictions that will facilitate future studies and management plans.
7 Africa Groundwater Network (AGW-Net). 2015. Training manual on integration of groundwater management into transboundary basin organizations in Africa. Hanover, Germany: Federal Institute for Geosciences and Natural Resources (BGR); Harare, Zimbabwe: Africa Groundwater Network (AGW-Net); Rio de Janeiro, Brazil: Computer Aided Provider Network (Cap-Net). 219p.
Groundwater management ; Groundwater extraction ; Groundwater recharge ; Groundwater flow ; Aquifers ; Water resources ; International waters ; River basins ; Water use ; Water balance ; Surface water ; Water allocation ; Water quality ; Water pollution ; International organizations ; Assessment ; Sustainability ; Hydrological cycle ; Monitoring ; Living standards ; Food security ; Climate change ; Adaptation ; Environmental effects ; Ecosystems ; Irrigation development ; Information management ; Cost benefit analysis ; Legal aspects ; Regulations ; Licences ; Stakeholders ; Contamination ; Case studies ; Training materials / Africa
(Location: IWMI HQ Call no: 333.9104 G100 AFR Record No: H047239)
https://www.bgr.bund.de/EN/Themen/Zusammenarbeit/TechnZusammenarb/Politikberatung_GW/Downloads/Trainingsmanual.pdf?__blob=publicationFile&v=7
https://vlibrary.iwmi.org/pdf/H047239.pdf
https://vlibrary.iwmi.org/pdf/H047239.pdf
(5.46 MB) (5.46 MB)
8 Hogeboom, R. H. J.; van Oel, P. R.; Krol, M. S.; Booij, M. J. 2015. Modelling the influence of groundwater abstractions on the water level of Lake Naivasha, Kenya under data-scarce conditions. Water Resources Management, 29(12):4447-4463. [doi: https://doi.org/10.1007/s11269-015-1069-9]
Groundwater extraction ; Water levels ; Mathematical models ; Groundwater flow ; Water balance ; Irrigation water ; Water use ; Lakes ; Hydrological data ; Calibration / Kenya / Rift Valley / Lake Naivasha / Flower Business Park
(Location: IWMI HQ Call no: e-copy only Record No: H047906)
http://link.springer.com/content/pdf/10.1007%2Fs11269-015-1069-9.pdf
https://vlibrary.iwmi.org/pdf/H047906.pdf
https://vlibrary.iwmi.org/pdf/H047906.pdf
(4.38 MB) (4.38 MB)
This study presents the state-of-the-art understanding of the data-scarce and hydrogeologically complex groundwater system of Lake Naivasha, Kenya, with the particular aim of exploring the influence groundwater abstractions have on Lake Naivasha’s water level. We developed multiple alternative but plausible parameterizations for a MODFLOW groundwater model, based on literature, existing models and available data, while trying not to over-complicate the model. In doing so, we illustrate a possible strategy of going about data-scarce regions in modelling in general. Processes encountered in the calibrated parameterizations show groundwater flows laterally from the escarpments to the valley floor and axially from the lake along the Rift, with a larger portion flowing out southward than northward. Extraction of groundwater interrupts the flow from the northwestern highlands to the lake, leading to a lake stage reduction of 0.7–7.5 cm due to abstractions at our target farm (Flower Business Park) or an implied 7–75 cm due to total groundwater abstractions in the area. Although this study demonstrates our understanding of Naivasha’s groundwater system remains fragile and the current model cannot be embedded in operational water management yet, it (i) reflects the contemporary understanding of the local groundwater system, (ii) illustrates how to go about modelling in data-scarce environments and (iii) provides a means to assess focal areas for future data collection and model improvements.
9 Sonkamble, S.; Sahya, A.; Jampani, M.; Ahmed, S.; Amerasinghe, Priyanie. 2019. Hydro-geophysical characterization and performance evaluation of natural wetlands in a semi-arid wastewater irrigated landscape. Water Research, 148: 176-187. [doi: https://doi.org/10.1016/j.watres.2018.10.040]
Wastewater irrigation ; Performance appraisals ; Wetlands ; Electrical resistance ; Tomography ; Hydrogeology ; Pollutants ; Semiarid zones ; Groundwater flow ; Contamination / Southern India / Musi River
(Location: IWMI HQ Call no: e-copy only Record No: H048961)
Natural wetlands are green infrastructure systems that are energy-efficient for wastewater treatment and can be found in diverse geo-environmental settings around the world. Their structure and functions, which defines the treatment efficiencies are highly varied. Wetlands over shallow bedrock and geological lineaments (weak zones) have been known to contribute to groundwater contamination. However, not many studies have been performed to understand the structure in different geological settings to identify the efficiency determining factors. Therefore, it is important to investigate the geological suitability of the natural wetlands. We examined wastewater fed natural wetlands in diverse geological settings aiming at studying the depth, geo-stability, bio-chemical interactions, and hydrogeological attributes that improve the wastewater quality, within the Musi River basin, India. The integrated geophysical scans encompassing electrical resistivity tomography (ERT), hydrogeological test, bathymetric study and hydro-chemical analysis were carried out to explore the physical structure and hydro-dynamic processes in the wetlands. ERT investigations showed that, the depth to bedrock up to 20–25 m devoid of geo-fractures (lineaments) indicated the effective depth of saturated zone as a passable scope for potential bio-chemical interactions, implying the proportionality of the deep seated (deep bedrock) wetland to the pollutant removal efficiency. The lower order of electrical resistivity range 10–35 Om and hydraulic conductivity 2.938 md-1 acquired for saturated weathered zone were found catalyzing the bioremediation, sedimentation, adsorption, redox reactions and ion exchange processes. It caused the deep seated wetland removing nitrate 194.34 kgd-1 (97.18%); sulphate 333.75 kgd-1 (77.70%); phosphate 9.66 kgd-1 (82.53%); microbes 99.99%, BOD 80%, and COD 80% load with discharge 1408 m3d-1 of treated wastewater. Further, the strategies for designating the natural wetlands as wastewater treatment systems are also discussed in this paper.
10 Walker, D.; Parkin, G.; Schmitter, Petra; Gowing, J.; Tilahun, S. A.; Haile, Alemseged T.; Yimam, A. Y. 2019. Insights from a multi-method recharge estimation comparison study. Groundwater, 57(2): 245-258. [doi: https://doi.org/10.1111/gwat.12801]
Hydrogeology ; Aquifers ; Groundwater recharge ; Groundwater flow ; Water storage ; Water resources development ; Water levels ; Water table ; Uncertainty ; Rain / Ethiopia
(Location: IWMI HQ Call no: e-copy only Record No: H048963)
https://onlinelibrary.wiley.com/doi/epdf/10.1111/gwat.12801
https://vlibrary.iwmi.org/pdf/H048963.pdf
https://vlibrary.iwmi.org/pdf/H048963.pdf
(938 KB)
Although most recharge estimation studies apply multiple methods to identify the possible range in recharge values, many do not distinguish clearly enough between inherent uncertainty of the methods and other factors affecting the results. We investigated the additional value that can be gained from multi-method recharge studies through insights into hydrogeological understanding, in addition to characterizing uncertainty. Nine separate groundwater recharge estimation methods, with a total of 17 variations, were applied at a shallow aquifer in northwest Ethiopia in the context of the potential for shallow groundwater resource development. These gave a wide range of recharge values from 45 to 814 mm/a. Critical assessment indicated that the results depended on what the recharge represents (actual, potential, minimum recharge or change in aquifer storage), and spatial and temporal scales, as well as uncertainties from application of each method. Important insights into the hydrogeological system were gained from this detailed analysis, which also confirmed that the range of values for actual recharge was reduced to around 280-430 mm/a. This study demonstrates that even when assumptions behind methods are violated, as they often are to some degree especially when data are limited, valuable insights into the hydrogeological system can be gained from application of multiple methods.
11 Kpegli, K. A. R.; van der Zee, S. E. A. T. M.; Alassane, A.; Bier, G.; Boukari, M.; Leijnse, A.; de Louw, P. G. B.; Mama, D. 2018. Impact of hydraulic and storage properties on river leakage estimates: a numerical groundwater flow model case study from southern Benin. Journal of Hydrology: Regional Studies, 19:136-163. [doi: https://doi.org/10.1016/j.ejrh.2018.07.004]
River basins ; Leakage ; Estimation ; Hydraulic conductivity ; Water storage ; Groundwater flow ; Models ; Groundwater recharge ; Aquifers ; Discharges ; Water loss ; Groundwater extraction ; Water budget ; Hydrogeology ; Case studies / Benin / Zou River / Ouémé River
(Location: IWMI HQ Call no: e-copy only Record No: H048921)
(10.90 MB)
Study area: The coastal sedimentary basin including the Zou and Ouémé rivers in Benin.
Study focus: River discharge loss is known to occur on the Zou and Ouémé rivers in southern Benin since a couple of decades ago. The reason behind this discharge reduction remained so far unclear. In this study, we focus on creating a 3D-numerical model of the system and on evaluating the sensitivity of leakage between the rivers and aquifers to various parameters.
New hydrological insights for the region: Results show that leakages along the Zou river and Ouémé stream are tiny (i.e., ~3% of the discharge losses). This implies that the observed water loss from the Zou and Ouémé rivers is not likely caused by the leakage (infiltration) along these rivers into the subsurface. The streambed conductance is found to be among the factors that impact less the computed leakages in the study area. This study has ranked the different hydraulic and storage properties in their order of importance with respect to the computation of river leakages along the concerned rivers. The determined rank of importance of the hydraulic and storage properties can guide river leakage modelling exercises in similar regions elsewhere.
Study focus: River discharge loss is known to occur on the Zou and Ouémé rivers in southern Benin since a couple of decades ago. The reason behind this discharge reduction remained so far unclear. In this study, we focus on creating a 3D-numerical model of the system and on evaluating the sensitivity of leakage between the rivers and aquifers to various parameters.
New hydrological insights for the region: Results show that leakages along the Zou river and Ouémé stream are tiny (i.e., ~3% of the discharge losses). This implies that the observed water loss from the Zou and Ouémé rivers is not likely caused by the leakage (infiltration) along these rivers into the subsurface. The streambed conductance is found to be among the factors that impact less the computed leakages in the study area. This study has ranked the different hydraulic and storage properties in their order of importance with respect to the computation of river leakages along the concerned rivers. The determined rank of importance of the hydraulic and storage properties can guide river leakage modelling exercises in similar regions elsewhere.
12 Hester, E. T.; Eastes, L. A.; Widdowson, M. A. 2019. Effect of surface water stage fluctuation on mixing-dependent hyporheic denitrification in riverbed dunes. Water Resources Research, 55(6):4668-4687. [doi: https://doi.org/10.1029/2018WR024198]
Rivers ; Dunes ; Surface water ; Hydraulics ; Denitrification ; Groundwater flow ; Stream flow ; Sediment ; Nitrates ; Oxygen ; Models ; Environmental effects
(Location: IWMI HQ Call no: e-copy only Record No: H049256)
(3.49 MB)
The hyporheic zone, where surface water (SW) and groundwater (GW) interact in shallow sediments beneath rivers, is uniquely reactive and attenuates pollutants. Mixing of reactants from SW and GW enables mixing-dependent (MD) reactions, which may be the last opportunity for GW contaminants to react before entering SW. Yet little is known about hyporheic MD reactions, particularly how they respond to daily or seasonal SW fluctuations or sediment heterogeneity. We used MODFLOW and SEAM3D to simulate non-mixing-dependent (NMD) aerobic respiration and MD denitrification in a riverbed dune with nitrate from SW and dissolved organic carbon from GW. We varied SW heads and heterogeneity of sediment hydraulic conductivity. For longer-term fluctuations (i.e., seasons), increasing SW depth from 0.1 to 1.0 m increased NMD aerobic respiration by 270% and MD denitrification by 78% in homogeneous sediment. MD reactions thus were controlled by mixing zone length or size and would be stronger when SW stage is elevated, for example, during wintertime. Adding sediment heterogeneity to the long-term scenarios, particularly by increasing hydraulic conductivity correlation length, increased flow focusing and consequently increased MD denitrification by 20–30%. By contrast, the net effect of daily SW fluctuations on MD denitrification in homogeneous sediment was minor. In sum, SW fluctuations are an important control on hyporheic MD reactions, primarily by controlling mixing zone length. The hyporheic zone may attenuate nitrate in upwelling GW plumes, but temporal fluctuations may be considerable as quantified above.
13 Thangarajan, M.; Singh, V. P. (Eds.) 2016. Groundwater assessment, modeling, and management. Boca Raton, FL, USA: CRC Press. 511p.
Groundwater assessment ; Groundwater management ; Models ; Water availability ; Water quality ; Water purification ; Water use ; Water resources ; Groundwater flow ; Groundwater recharge ; Alluvial aquifers ; Climate change ; Coastal area ; Water pollution ; Saline water ; Arsenic ; Contamination ; Freshwater ; Carbon dioxide ; Ion exchange ; Fluorides ; Hydraulic conductivity ; Geographical information systems ; Forecasting ; Optimization ; Food security ; Agricultural production ; Rice ; Rivers ; Hydrogeology ; Hydraulic fracturing ; Case studies / Africa South of Sahara / Southern Africa / East Africa / India / Brazil / Botswana / Okavango Delta / Cauvery River / Ganges River / Boro River Valley / Gangetic Plains / Maharashtra / Tamil Nadu
(Location: IWMI HQ Call no: e-copy SF Record No: H049342)
14 Nonterah, C.; Xu, Y.; Osae, S. 2019. Groundwater occurrence in the Sakumo Wetland Catchment, Ghana: model-setting-scenario approach. Hydrogeology Journal, 27(3):983-996. [doi: https://doi.org/10.1007/s10040-019-01959-4]
Groundwater flow ; Wetlands ; Catchment areas ; Models ; Aquifers ; Water levels ; Groundwater recharge ; Hydrogeology ; Precipitation / Africa South of Sahara / Ghana / Accra / Sakumo Wetland Catchment
(Location: IWMI HQ Call no: e-copy only Record No: H049346)
(3.25 MB)
Water flow is required for the health and integrity of any wetland environment. Based on field investigation, flow simulation and hydrogeological data, a conceptual flow model representing the physical characteristics of the Sakumo wetland (Ghana) was developed. Two major flow systems were identified: interflow (local topsoil water) in the alluvium and shallow groundwater flow in the unconfined unit. A simple two-dimensional finite-difference numerical model was applied to analyse the groundwater flow system in the Sakumo wetland catchment using ModelMuse. The purpose of the model was to explain the groundwater flow system and quantify the water fluxes contributing to the wetland water storage. The main source of groundwater for use in the catchment is the shallow unconfined Quaternary aquifer. The modelling results indicate that changes in recharge significantly affect the wetland water balance. The water table declines during the dry season as there is high evapotranspiration with little rain. The modelling results also confirm that the Sakumo wetland water fluxes are predominately associated with local shallow flows; the calibrated model simulation showed no hydraulic link between the wetland and the underlying deep basement aquifer. This study thus provides valuable hydrogeological information on the Sakumo wetland basin and lays the foundation for development of detailed future predictive models in this under-researched area of hydrogeology in the humid tropics.
15 Matengu, B.; Xu, Y.; Tordiffe, E. 2019. Hydrogeological characteristics of the Omaruru Delta Aquifer System in Namibia. Hydrogeology Journal, 27(3):857-883. [doi: https://doi.org/10.1007/s10040-018-1913-0]
Aquifers ; Deltas ; Hydrogeology ; Groundwater recharge ; Artificial recharge ; Catchment areas ; Groundwater table ; Groundwater flow ; Water balance ; Coastal area ; Sediment ; Sustainability / Africa South of Sahara / Namibia / Omaruru Delta Aquifer System / Omdel Aquifer / Omaruru River
(Location: IWMI HQ Call no: e-copy only Record No: H049357)
https://link.springer.com/content/pdf/10.1007%2Fs10040-018-1913-0.pdf
https://vlibrary.iwmi.org/pdf/H049357.pdf
https://vlibrary.iwmi.org/pdf/H049357.pdf
(2.77 MB) (2.77 MB)
Sustainable utilization of groundwater in parts of hyper-arid Sub-Saharan Africa, like the Namib Desert, is always a challenge due to lack of resources and data. For the Omdel Aquifer in the Omaruru catchment, Namibia, issues to investigate include the lack of information on the geology and hydrogeological setting, the hydraulic properties and geometry of the aquifer at the inflow and outflow sections, groundwater recharge conditions upstream of the aquifer, and the impact of artificial recharge. In this desert environment, the methods applied are hydrogeological surveys and site visits, together with interpretation of geological, hydrological and geomorphological data from investigations carried out to define the hydrogeological characteristics of the Omdel Aquifer. The bedrock geometry of the aquifer indicates that the Main channel (one of four palaeochannels) is the largest reservoir of stored fresh groundwater, estimated at 133 Mm3, and it is deeper than the other three channels, with an average sediment thickness of 80 m. All groundwater chemistry facies of the selected boreholes tapping the Omdel Aquifer reveal a NaCl character, indicating a coastal environment. The yield of the Omdel Aquifer is estimated to have increased from 2.8 Mm3/year before construction of a recharge enhancement dam to 4.6 Mm3/year after the construction. This paper focuses on the understanding of hydrogeological characteristics of the Omaruru Delta Aquifer System in terms of groundwater recharge and discharge, groundwater dynamics within the aquifer and groundwater chemistry, in order to assess whether the current abstractions are operating within the hydrogeological limits of sustainability.
16 Baumle, R.; Himmelsbach, T.; Noell, U. 2019. Hydrogeology and geochemistry of a tectonically controlled, deep-seated and semi-fossil aquifer in the Zambezi Region (Namibia). Hydrogeology Journal, 27(3):885-914. [doi: https://doi.org/10.1007/s10040-018-1896-x]
Groundwater flow ; Aquifers ; Hydrogeology ; Geochemistry ; Tectonics ; Remote sensing ; Geophysics ; Rain ; Temperature ; Palaeoclimatology ; Models / Africa South of Sahara / Namibia / Zambezi River / Lower Kalahari Aquifer
(Location: IWMI HQ Call no: e-copy only Record No: H049358)
https://link.springer.com/content/pdf/10.1007%2Fs10040-018-1896-x.pdf
https://vlibrary.iwmi.org/pdf/H049358.pdf
https://vlibrary.iwmi.org/pdf/H049358.pdf
(16.60 MB) (16.6 MB)
Recent exploration has revealed that deep-seated and large groundwater reservoirs in Africa’s intracontinental basins can be regarded as an additional strategic resource for supply of drinking water. The origin, genesis and recharge of these groundwater reservoirs, however, are still poorly understood. A multidisciplinary approach involving remote sensing, geophysical surveys and hydraulic investigations, as well as hydrochemical and isotope studies, was pursued to gain better insight into the genesis and the potential of a recently discovered lower Kalahari aquifer (LKA) located in the Zambezi Region (Namibia). The study shows that regional tectonic activity associated with the propagation of the Okavango Rift Zone had a tremendous impact on the drainage evolution and hydrogeological setting of the region. Furthermore, there is geomorphological evidence that the LKA—prior to tectonic subsidence and burial—was part of a paleochannel of the upper Zambezi River. Hydraulic continuity could be confirmed by geochemical evolution down the flow path. Cation exchange combined with dissolution of calcite progressively produces alkalinity and sodium and consumes calcium in the north–south direction. Comparison of stable isotope content of the LKA with modern rainfall indicates that the recharge occurred under cooler climate conditions. Analysis of 14C concentrations and 36Cl/Cl ratios show that the age of the groundwater exceeds 100 ka and is hence older than presumed. It is concluded that the assessment of the sedimentology, tectonic structures and geochemistry are key factors for understanding both the paleoclimatic and modern recharge processes of deep-seated aquifer systems.
17 Thapa, Bhesh Raj; Ishidaira, H.; Gusyev, M.; Pandey, Vishnu Prasad; Udmale, P.; Hayashi, M.; Shakya, N. M. 2019. Implications of the Melamchi water supply project for the Kathmandu Valley groundwater system. Water Policy, 21(S1):120-137. [doi: https://doi.org/10.2166/wp.2019.084]
Water supply ; Groundwater management ; Groundwater flow ; Models ; Groundwater extraction ; Pumping ; Wells ; Water resources ; Water deficit ; Water demand ; Watersheds ; Aquifers ; Valleys / Nepal / Kathmandu Valley / Melamchi Water Supply Project
(Location: IWMI HQ Call no: e-copy only Record No: H049465)
https://iwaponline.com/wp/article-pdf/21/S1/120/632511/021000120.pdf
https://vlibrary.iwmi.org/pdf/H049465.pdf
https://vlibrary.iwmi.org/pdf/H049465.pdf
(0.89 MB) (912 KB)
To meet the demand deficit in Kathmandu Valley, the Government of Nepal has planned to supply an additional 510 million liters per day (mld) of water by implementing the Melamchi Water Supply Project (MWSP) in the near future. In this study, we aim to assess the spatial distribution of groundwater availability and pumping under five scenarios for before and after the implementation of the MWSP using a numerical groundwater flow model. The data on water demand, supply infrastructure, changes in hydraulic head, groundwater pumping rates, and aquifer characteristics were analyzed. Results showed that groundwater pumping from individual wells ranges from 0.0018 to 2.8 mld and the average hydraulic head declined from 2.57 m below ground level (bgl) (0.23 m/year) to 21.58 m bgl (1.96 m/year). Model simulations showed that changes in average hydraulic head ranged from þ2.83 m to þ5.48 m at various stages of the MWSP implementation, and 2.97 m for increased pumping rates with no implementation of the MWSP. Regulation in pumping such as monetary instruments (groundwater pricing) on the use of groundwater along with appropriate metering and monitoring of pumping amounts depending on the availability of new and existing public water supply could be interventions in the near future.
18 Faye, S. C.; Diongue, M. L.; Pouye, A.; Gaye, C. B.; Travi, Y.; Wohnlich, S.; Faye, S.; Taylor, R. G. 2019. Tracing natural groundwater recharge to the Thiaroye Aquifer of Dakar, Senegal. Hydrogeology Journal, 27(3):1067-1080. (Special issue: Groundwater in Sub-Saharan Africa) [doi: https://doi.org/10.1007/s10040-018-01923-8]
Groundwater recharge ; Aquifers ; Semiarid zones ; Urban areas ; Groundwater flow ; Groundwater table ; Monsoon climate ; Rain ; Chemical composition ; Isotopes / Senegal / Dakar / Thiaroye aquifer
(Location: IWMI HQ Call no: e-copy only Record No: H049362)
https://link.springer.com/content/pdf/10.1007%2Fs10040-018-01923-8.pdf
https://vlibrary.iwmi.org/pdf/H049362.pdf
https://vlibrary.iwmi.org/pdf/H049362.pdf
(5.43 MB) (5.43 MB)
Urban groundwater in Sub-Saharan Africa provides vital freshwater to rapidly growing cities. In the Thiaroye aquifer of Dakar (Senegal), groundwater within Quaternary unconsolidated sands provided nearly half of the city’s water supply into the 1980s. Rising nitrate concentrations traced to faecal contamination sharply curtailed groundwater withdrawals, which now contribute just 5% to Dakar’s water supply. To understand the attenuation capacity of this urban aquifer under a monsoonal semi-arid climate, stable-isotope ratios of O and H and radioactive tritium (3H), compiled over several studies, are used together with piezometric data to trace the origin of groundwater recharge and groundwater flowpaths. Shallow groundwaters derive predominantly from modern rainfall (tritium >2 TU in 85% of sampled wells). d18O and d2H values in groundwater vary by >4 and 20‰, respectively, reflecting substantial variability in evaporative enrichment prior to recharge. These signatures in groundwater regress to a value on the local meteoric water line that is depleted in heavy isotopes relative to the weighted-mean average composition of local rainfall, a bias that suggests recharge derives preferentially from isotopically depleted rainfall observed during the latter part of the monsoon (September). The distribution of tritium in groundwater is consistent with groundwater flowpaths to seasonal lakes and wetlands, defined by piezometric records. Piezometric data further confirm the diffuse nature and seasonality of rain-fed recharge. The conceptual understanding of groundwater recharge and flow provides a context to evaluate attenuation of anthropogenic recharge that is effectively diffuse and constant from the vast network of sanitation facilities that drain to this aquifer.
19 Grzybowski, M.; Lenczewski, M. E.; Oo, Y. Y. 2019. Water quality and physical hydrogeology of the Amarapura township, Mandalay, Myanmar. Hydrogeology Journal, 27(4):1497-1513. [doi: https://doi.org/10.1007/s10040-018-01922-9]
Water quality ; Hydrogeology ; Groundwater development ; Urban areas ; Groundwater table ; Aquifers ; Groundwater flow ; Drinking water ; Well construction ; Geochemistry ; Wastewater ; Escherichia coli ; Hydraulic conductivity ; Electrical conductivity ; Models / Myanmar / Mandalay / Amarapura
(Location: IWMI HQ Call no: e-copy only Record No: H049365)
https://link.springer.com/content/pdf/10.1007%2Fs10040-018-01922-9.pdf
https://vlibrary.iwmi.org/pdf/H049365.pdf
https://vlibrary.iwmi.org/pdf/H049365.pdf
(4.08 MB) (4.08 MB)
Mandalay is a major city in central Myanmar with a high urban population and which lacks a central wastewater management system, a solid waste disposal process, and access to treated drinking water. The purpose of this study is to investigate the groundwater quality of local dug wells and tube wells, determine quantitative data on characteristics of the Amarapura Aquifer, and compare seasonal variations in groundwater flow and quality. Water samples were collected during the dry and wet seasons, then analyzed for major ion chemistry using ion chromatography to identify indicators of wastewater contamination transport to the shallow aquifer and to compare seasonal variations in groundwater chemistry. An open-source analytic element model, GFLOW, was used to describe the physical hydrogeology and to determine groundwater flow characteristics in the aquifer. Hydrogeochemistry data and numerical groundwater flow models provide evidence that the Amarapura Aquifer is susceptible to contamination from anthropogenic sources. The dominant water types in most dug wells and tube wells is Na-Cl, but there is no known geologic source of NaCl near Mandalay. Many of these wells also contain water with high electrical conductivity, chloride, nitrate, ammonium, and E. coli. Physical measurements and GFLOW characterize groundwater flow directions predominantly towards the Irrawaddy River and with average linear velocities ranging from 1.76 × 10-2 m/day (2.04 × 10-7 m/s) to 9.25 m/day (1.07 × 10-4 m/s). This is the first hydrogeological characterization conducted in Myanmar.
20 Patil, N. S.; Chetan, N. L.; Nataraja, M.; Suthar, S. 2020. Climate change scenarios and its effect on groundwater level in the Hiranyakeshi Watershed. Groundwater for Sustainable Development, 10:100323. [doi: https://doi.org/10.1016/j.gsd.2019.100323]
Groundwater table ; Climate change ; Watersheds ; Groundwater recharge ; Rivers ; Groundwater flow ; Models ; Water availability ; Precipitation ; Temperature / India / Ghataprabha Sub-Basin / Hiranyakeshi Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H049689)
(1.62 MB)
The availability of groundwater resources is depleting due to growth of population, urbanization, industrialization and climate change. With increasing concern on global climate change all over the world, there has been raising interest on water resource conservation. Similarly, Hukkeri (lies within Hiranyakeshi watershed) is one such town under Belagavi, Karnataka is facing severe groundwater problems from the past few years due to uneven rainfall, climate change and over exploitation of groundwater for irrigation activities. This study focused to measure and evaluate groundwater resources by modelling approach for the Hiranyakeshi watershed using Visual MODFLOW Flex software (Modular Finite Difference Groundwater Flow Model). The model calibration achieved by Parameter Estimation (PEST), and the model performance was checked by using coefficients R2, RMSE and NRMSE. It is observed that the coefficients of R2, RMSE and NRMSE obtained are 0.98, 1.68 and 3.41% respectively. The results from the model simulation gives increase in head of 1.8 m during 5years simulation period. The model was again simulated for the A1B climate change scenarios for the period 2021–2050 using Hadley Regional Model 3 (HadRM3) data for the Hiranyakeshi watershed to measure the effects of climate change on the groundwater recharge. Based on the long term output analysis, it is expected that there is an increase in the average annual temperature by 2.59 °C, precipitation by 81.50% and groundwater recharge by 24.91%.
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