Estimated groundwater recharge under cascade dams (141,407 m 3/year) is greater than recharge estimated for gravity dam (103,853 m 3/year) by at least 36%. These check dams will slow down the runoff flow, form small reservoirs, and enhance recharge along the valley, without requiring expensive foundations. Instead, a series of three low check dams (2 to 4 m high) was proposed. Using gravity dam at Wadi Bahaman for groundwater recharge proved not suitable based on the relatively small predicted runoff from a small catchment area and geological concerns in the abutment areas. The water balance model was used to estimate recharge at Wadi Bahaman, under gravity and cascade dams’ scenarios. A general conclusion of this comparison is that the hydraulic conductivity ( K) is the main determining factor in recharge calculations in these situations. This is because, despite Darcian approach that should have affected the recharge rate as other parameters were introduced in the calculation of q t, e.g., groundwater table mound, reservoir water height, etc., the results show general agreement between the two methods which seem to validate the assumptions made in both methods. By applying the two models at three new dam sites, the amount of recharge rates calculated over the period 2007–2026 was close. In arid country with limited resources, two simple techniques have been used for recharge estimation: (1) a simple water balance model in spreadsheet and (2) a more refined Darcian approach involving an analytical approximation of a flow-net solution. Combined, these constraints require an approach which involves best use of available data, adoption of relatively simple analytical approximations of reality, and the adoption of several key assumptions. In approaching the task of developing recharge estimates for dam sites, several constraints are apparent, including the scarcity of site-specific data for the selected new sites and the availability of simple yet robust analysis techniques.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
January 2023
Categories |