Effects of a bypass-type multistage sand-filled dam on water supply in a drought-vulnerable area in Mullocheon catchment, South Korea

Abstract

Study region

Mullocheon catchment, Gangwon-do, South Korea

Study focus

Climate change can lead to extreme droughts worldwide, and regions relying on valley streams without large reservoirs are more vulnerable to drought. To address this, a bypass-type multistage sand-filled dam (BMSD) was constructed in a drought-prone area in South Korea, specifically in the Mullocheon catchment, to supply water to a small-population village. The BMSD was connected in series with an existing small pond, and the drainage rates were integrated through a single conduit. Quantitatively analyzing the contribution of the newly constructed sand-filled dam was challenging, so this study investigated the effect of the sand dam on water supply capacity using a bed-mounted infiltration system. The contribution of the sand-filled dam to the total drainage rate was calculated using observation data.

New hydrological insights for the region

The hydraulic conductivity of the riverbed and the drainage rate of the intake pond were estimated using the observed water level and flow rate. Prior to the installation of the sand dam, from January to May 2021, the total precipitation was approximately 284.72 mm, and the average drainage rate was 76.78 m³/d. After the sand dam was installed, from January to May 2022, the precipitation was 165.13 mm, and the average drainage rate increased by 45.4 % to 124.49 m³/d. It was observed that during normal periods, the supply was more than three times greater than before, and even during droughts, the supply met the residents' needs. This indicates that the sand-filled dam’s storage effect has enhanced drought resilience.