ĐÁNH GIÁ HIỆU QUẢ CỦA ĐẬP NGẦM LÀM CHẬM DÒNG CHẢY TRONG TẦNG CUỘI SỎI VÙNG NINH THUẬN, BÌNH THUẬN

Abstract

A subsurface dam is a structure that is arranged across a groundwater channel to store shallow groundwater or slow down the seepage in the aquifer (sand, gravel, etc…). Subsurface dam technologies have been widely applied and documented in the literature, especially in dry riverbeds around the world. However, there are a few assessments of the efficiency of the available technologies, particularly the efficiency of the subsurface dam type that is partly cut-off the interflows in gravel layers. This paper presents the solutions of designing and implementing as well as monitoring results of a full-scale experiment of a semi-cross-section arrangement subsurface dam at a freshwater treatment plant in My Thanh commune, Ham Thuan Nam district, Binh Thuan province (with a design capacity of 80 m³/day in the dry season), a region where experiences severe droughts in the last 3 months of the dry season. It is found that when the subsurface dam was constructed, the water treatment plant supplied sufficient water as designed and the groundwater storage exceeded the actual yield about 6000m³. This is a good reference for applying the subsurface dam in those places that have similar geological conditions.