2024 NATIONAL WATER CONFERENCE AND EXHIBITION | BICC | LILONGWE | MALAWI
Reliable hydrological time series data is required to effectively and efficiently assess water availability. However, globally there is a dense decline in hydrological data, which makes it challenging to assess water availability. Remotely acquired data can be an alternative data source. The study aimed to assess water availability using remote sensing in the South Rukuru and North Rumphi River Basin. Specifically, the study sought to (a) develop a remote-sensing rainfall-runoff model and (b) conduct a performance analysis of the remote-sensing rainfall-runoff model. A rainfall-runoff (soil moisture method) hydrological model was developed using the Water Evaluation and Planning (WEAP) modelling software to assess the water availability. The WEAP inputs included the Global Land Data Assimilation System (GLDAS) climate datasets, Elevation data, and the Land Use Land Cover. The observed streamflow data was used to calibrate and validate the WEAP model. The performance of the WEAP model simulation was assessed, and the monthly measured and simulated streamflow statistics showed a positive, strong relationship (R2 = 0.81, NSE = 0.81, IA = 0.95, KGE = 0.89 and PBIAS of -3.8) at gauging station 7G18. Similarly, there was a good agreement between the monthly measured and simulated streamflow at gauging station 7H3 (R2 = 0.94, NSE = 0.93, IA = 0.98, KGE = 0.85 and PBIAS of -9.3). The WEAP model developed can estimate nearly all components of the hydrological cycle. The hydrological response showed that in months at which the precipitation was at its peak, the water availability was also at its peak. Therefore, this remote sensing rainfall runoff WEAP model can be used as a baseline for assessing water availability when insufficient, inconsistent or fragmented observed hydrological data exists.
Keywords: Water Availability, Remote Sensing, WEAP, Soil Moisture Method, GLDAS
