Your search found 4 records
1 Dewandel, B.; Perrin, J.; Ahmed, S.; Aulong, S.; Hrkal, Z.; Lachassagne, P.; Samad, Madar; Massuel, S. 2010. Development of a tool for managing groundwater resources in semi-arid hard rock regions: application to a rural watershed in South India. Hydrological Processes, 24(19):2784–2797. [doi: https://doi.org/10.1002/hyp.7696]
(Location: IWMI HQ Call no: e-copy only Record No: H043174)
(0.33 MB)
Until recently, aquifers located in hard rock formations (granite, gneiss, schist) were considered as a highly heterogeneous media, and no adequate methodology for groundwater management was available. Recent research studies have shown that when hard rocks are exposed to regional and deep-weathering processes and when the geology is relatively homogenous, a typical hard rock aquifer is made of two main superimposed hydrogeological layers each characterized by quite homogeneous specific hydrodynamic properties: namely the saprolite and the fissured layers. Therefore, for these cases, hard rock aquifers can be considered as a multi-layered system. Based on these works, an operational decision support tool (DST-GW ) designed for the management of groundwater resources in hard rock area under variable agro-climatic conditions has been developed. The tool focuses on the impact of changing cropping pattern, artificial recharge and rainfall conditions on groundwater levels at the scale of small watersheds (10 to about 100 km2 in case well-developed weathering profile). DST-GW is based on the groundwater balance and the ‘water table fluctuation method’, which are well-adapted methods in hard rock and semiarid contexts. Based on field data from an overexploited South Indian watershed (58 km2), the model allows calibrating, at watershed scale, the variation in specific yield of the aquifer with depth, as well as the rainfall-aquifer recharge relationship. Seasonal basin-scale piezometric levels are computed with an average deviation of š0Ð56 m compared to measurements from 2001 to 2005. The model shows that, if no measure is taken, the water table depletion will induce the drying-up of most of the exploited borewells by the year 2012. Scenarios of mitigation measures elaborated with the tool show that change in cropping patterns could rapidly reverse the tendency and lead to a sustainable management of the resource. This work presents the developed tool and particularly the hydraulic model involved in and its application to a case study. However, the purpose tool is applicable at watershed scale but not design for the groundwater management of a very small area or for a single borewell.
2 Schmitt, R.; Amerasinghe, Priyanie H.; Perrin, J.; Dinis, L.; Ahmed, S.; Pavelic, Paul. 2010. Towards the development of a methodology to assess hydrological impacts of wastewater irrigation on groundwater: a case study from Hyderabad, India. [Abstract only]. Paper presented at the Annual Tropical and Subtropical Agricultural and Natural Resource Management (Tropentag) Conference on World Food System - a contribution from Europe, Thematic scientific session on Water management, Zurich, Switzerland, 14 -16 September 2010. 2p. (published online)
Wastewater irrigation ; Groundwater ; Impact assessment ; Hydrological factors ; Case studies / India / Andhra Pradesh / Hyderabad / Musi River
(Location: IWMI HQ Call no: e-copy only Record No: H043223)
http://www.tropentag.de/2010/abstracts/links/Schmitt_2rQBM1Rw.pdf
https://vlibrary.iwmi.org/pdf/h043223.pdf
https://vlibrary.iwmi.org/pdf/h043223.pdf
(0.11 MB)
In the lands adjacent to the Musi-River, downstream of the city of Hyderabad, India, wastewater reuse for irrigation of various crops is common. Studies have shown that poor water quality has been a driver for crop selection in this area and this study describes the methodological approach used to understand the hydrological impacts and processes on groundwater associated with wastewater irrigation of a variety of crop types. An area (2.8km2) comprising wastewater- and groundwater-irrigated agriculture was selected based on landuse maps and observations. The watershed was delineated using DEM and GIS data. A crop model (BUDGET; Raes, 2005) was combined with field measure-ments, baseline data on irrigation practices, and land use patterns, to assess the overall water balance. The suitability of the method was validated with questionnaire survey results and available secondary data. 4 Piezometers were installed to assess and monitor groundwater levels and quality. Major crops irrigated with wastewater were found to be Paragrass (20 ha), Paddy (6 ha) and leafy vegetables (1.8 ha). Groundwater was used for Paddy (8 ha) and leafy vegetables (1.6 ha). Discharge from 17 wells or pumps was measured. Base line data for 23 distinct fields were collected. The annual irrigation flux was calculated to be 1.6×106 m3 and comprised of 77% wastewater, 23% groundwater. Return-flows from agriculture were 0.44×106m3 and madeup of 60% wastewater and 40% groundwater. There is neither a difference in the application rate of irrigation for paddy and Paragrass (n=12, p = 0.12) (Mann-Whitney-U-Test) nor in irrigation practices between wastewater and groundwater users (n=10, p = 0.10). The accuracy of survey results and crop modelling is dependant on crop type (p = 0.043, n=9) and season (p = 0.04, n=9). Piezometric measurements support differences in returnflows as modeled. Groundwater development is low, however, the irrigation return flows constitute an important source of ground water recharge. Findings indicate further potential for groundwater-based irrigation in wastewater irrigated areas maximizing the area under cultivation and benefits from the available water resources. These preliminary findings are being verified by more indepth studies that are presently underway and will finally allow the assessment different land and water use scenarios with regards to groundwater quality and quantity.
3 Schamper, C.; Pedersen, J. B.; Auken, E.; Christiansen, A. V.; Vittecoq, B.; Deparis, J.; Jaouen, T.; Lacquement, F.; Nehlig, P.; Perrin, J.; Reninger, P.-A. 2013. Airborne transient EM methods and their applications for coastal groundwater investigations. In Wetzelhuetter, C. (Ed.). Groundwater in the coastal zones of Asia-Pacific. Dordrecht, Netherlands: Springer. pp.121-151. (Coastal Research Library Volume 7)
Coastal area ; Groundwater ; Electromagnetic field ; Aerial surveying ; Models ; Mapping ; Aquifers ; Hydrogeology ; Salt water intrusion ; Case studies
(Location: IWMI HQ Call no: 551.457 G570 WET Record No: H046331)
For more than half a century airborne electromagnetic (AEM) methods have been used worldwide for cost-effective resistivity mapping of areas larger than several hundred km2. The technical developments and intensive use of these systems, principally in mining exploration during the first decades, led to the development of helicopter transient EM (HTEM) systems. Since the 2000s these systems provide the best lateral and vertical resolution for environmental exploration, and they still keep a good depth of investigation allowing the exploration from the first meters to depths of several hundred meters. This chapter focuses on helicopter borne transient electromagnetic (HTEM) systems, which are well suited for the detection of low resistive targets such as salt water intrusion in coastal zones. AEM methods are based on the diffusive induction phenomenon. It is a key tool for building realistic hydrogeological models; however it requires an understanding of its limits, and some insight into data processing modeling is necessary. They require careful processing, and removal of cultural EM noise, present in most survey areas, is mandatory in order to get high quality results. Accurate modeling of the data and of the system is also critical. The modeling is most often based on least-square optimization algorithms giving smooth or layered model descriptions of ground. In this chapter we describe the AEM method in detail and we discuss processing and inversion of data. To demonstrate the results from an investigation, we end the chapter with a case study of a SkyTEM survey made in the volcanic island of Mayotte where key geological structures and salt water intrusion were successfully mapped.
4 Jeelani, G.; Shah, R. A.; Deshpande, R. D.; Fryar, A. E.; Perrin, J.; Mukherjee, A. 2017. Distinguishing and estimating recharge to karst springs in snow and glacier dominated mountainous basins of the western Himalaya, India. Journal of Hydrology, 550:239-252. [doi: https://doi.org/10.1016/j.jhydrol.2017.05.001]
Water springs ; Recharge ; Karst ; Highlands ; Precipitation ; Snow cover ; Glaciers ; Snowmelt ; Flow discharge ; Temperature ; Rain ; Hydrogeology ; Hydrography ; Isotope analysis ; Elements ; Ions ; Chlorides ; Uncertainty / India / Western Himalaya / Liddar Basin / Kuthar Basin / Bringi Basin
(Location: IWMI HQ Call no: e-copy only Record No: H048190)
(4.76 MB)
Recharge assessment is a challenge in snow and glacier dominated Himalayan basins. Quantification of recharge to karst springs in these complex geological environments is important both for hydrologic understanding and for effective water resource management. We used spring hydrographs and environmental tracers (isotopes and solutes) to distinguish and estimate the sources of spring water and to identify the flow paths of the recharging waters in three mountainous basins of the western Himalaya. The karst springs are perennial with high discharge amplitudes. The results indicate that ambient temperature has a strong influence on the hydrological behavior of the springs. Although the spring flow is dominantly controlled by the melting of snow and/or glaciers, rain events produce sharp spikes in spring hydrographs. The facies patterns in springs within the Bringi basin (Ca-HCO3) and the Liddar basin (Ca-HCO3 and Ca-Mg-HCO3) suggest flow dominantly through limestone and dolomite. Higher concentrations of SO4 2 and Na+ in warm springs of the Kuthar basin indicate flow through carbonate, silicate and other rocks. The isotopic composition (d18O, d2 H) of precipitation, snowpacks, glacier melt and karst springs show wide variation both in space and time, and are strongly influenced by the basin relief and meteorology. The tracer-based two- and three-component mixing models suggest that the snowmelt dominantly contributes to the spring flow (55–96%), followed by glacier melt (5–36%) and rain (4–34%). Based on tracer tests with good recovery rates, springs are dominantly recharged through point sources rather than by diffuse infiltration. Changes in the timing, form, and amount of winter precipitation substantially affect the timing and magnitude of spring discharge during the rest of the year.
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