Determination of water balance components of a micro watershed for improved water management practices

Abstract

The incidents of water shortage are prevalent even in areas with high annual rainfall and are a serious issue requiring immediate attention. The uneven temporal distribution of rainfall, poor water conservation, and management are the primary reasons for this scarcity. A water balance study on a watershed basis can provide objective solutions to water scarcity and other water management issues. Hence, such a study on a sub-watershed of river Bharathapuzha, having a catchment area in and around Valanchery municipal town in Malappuram district, has been carried out in this research work. Major objectives of the study included the determination of monthly water balances of the watershed, developing relationships between them, and suggesting scientific water management practices for the watershed. Four automatic tipping bucket rain gauges were installed in the study area to record the rainfall. The stream runoff was determined by the area-velocity method, using automatic water level sensors, data loggers, and cup-type current meters. The soil moisture was measured using both capacitance and resistance-based soil moisture sensors, and a water level sensor recorded the groundwater level. The evapotranspiration (ET) was estimated using the FAO Penman-Monteith (PM) method and the water balance method. The sub-components of water balance were also assessed using the Soil and Water Assessment Tool (SWAT). The SWAT-CUP (Calibration and Uncertainty Programme) was used for sensitivity analysis and calibration of the model. The monthly and weekly relationships were found between the rainfall and other water balance components using R software. The soil and water conservation measures were suggested for the study based on the morphometric and water balance information.