Evaluation of water resources in mountainous region of Kathmandu Valley using high resolution satellite precipitation product

In Kathmandu valley, KUKL (Kathmandu Upatyka Khanepani Limited) is supplying potable water from the mountainous region of the valley to meet the daily demand but could meet only the 19% and 31% of total demand on dry and wet season respectively. The rapidly increased population, urbanization along with degraded water quality resulted water insecurity in Kathmandu Valley. Which motivated to access the potentiality of additional water harvesting from natural conservation zone for potable water supply. However, lacking of hydro meteorological gauges is challenging for water resources assessment and management from mountain in Kathmandu. Therefore, satellite-gauge merging precipitation data called bias reduction PERSIANN-CCS (BR-PER) was applied for stream-flow simulation for estimating the freshwater available on mountainous region to identify the possibility of water resources project development because BR-PER exploits the ability to capture the rainfall spatial variation from very high resolution satellite data PERSIANN-CCS and shows comparable rainfall magnitude estimations at the station scale. The model based simulation indicates the possibility to harness additional 67 MLD (million liters-a-day) and 87 MLD which is 18 % and 23 % of total current water demand can serve the additional 0.49 and 0.65 million of people in Kathmandu Valley during dry and wet season respectively. This statistics shows that if this additional available water will harnesses then it will reduced the ground water extraction rate and stress on groundwater resources. These could be short term solution to reduce the water insecurity in Kathmandu valley utilizing fresh water in sustainable way.