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Use of Environmental Isotope Tracer Techniques to Improve Basin-scale Recharge Estimation
Closed for proposals
Project Type
Project Code
F33017CRP
1529Approved Date
Status
Start Date
Expected End Date
Completed Date
12 December 2013Description
Groundwater is a vital to human and ecological health, and its importance as a drinking water, industrial and agricultural source will grow because of population increases and the expected impacts from land use and climate changes. There is therefore, a need to improve estimates of groundwater recharge (renewal) at the basin scale, which is the most relevant scale for water management. Quantifying groundwater recharge at this scale is difficult, and such a situation impedes sustainable use of groundwater resources. Environmental isotopes are powerful tools for recharge estimation, but because they yield rates that typically represent recharge at a point or within a limited area, their potential for basin scale estimation has not been realized. This CRP aims to apply environmental isotope tracer methods to quantify the recharge distribution within basins and to link these results to a GIS tool that can be used by Member States to upscale their isotope results and make better basin scale recharge estimations.
Objectives
To improve basin scale assessments of groundwater recharge in Member States through the combination of isotope tracer data and GIS tools. The objective will be met through integration of isotope based recharge estimates with GIS based upscaling methods. The results will contribute to sustainable management of groundwater resources.
Specific objectives
Compile broadly distributed isotope tracer based recharge estimates in selected basins from new analyses and/or existing data.
Develop a user-friendly GIS based approach that incorporates the correlation results for making spatially distributed, basin scale recharge estimates.
Examine correlations between the recharge estimates and basin characteristics or categories that can be determined through basin GIS analysis in a straightforward way. Significant correlations will be used to define zones or areas with a characteristic recharge rate or range within the basin.
Impact
This CRP could not be completed successfully. However, the four completed studies illustrated the relevance and importance of using geochemical/isotope methods to derive reliable estimates of groundwater recharge at point and basin scale. Upscaling recharge estimates to the basin hydrological characteristics and distribution of recharge rates at basin scale using GIS approach have been done successfully by few MS. However, as the CRP could not be concluded in the required manner, therefore, its impact is limited in using the techniques and methodology used/developed under this CRP.
Relevance
Normally, the recharge rates are estimated at point scale and the values are neither correlated with basin hydrological characteristics neither the point recharge rates are distributed at basin scale. The four studies completed have successfully illustrated the relevance and importance of using geochemical/isotope methods to derive reliable estimates of groundwater recharge at point scale. And upscaling recharge estimates to the basin hydrological characteristics and distribution of recharge rates at basin scale using GIS approach. Although the CRP is very relevant but the limited results obtained limits its relevance at large scale.