M3 – Hydrologic model: future water availability

Partner: IWW-MH in cooperation with UAF

Objective
Setting up a detailed hydrological model of the Lower Chenab Canal Area (LCC) in Pakistan will help to estimate changes in water availability due to shifting land use patterns, alternative crop management strategies, and potential climate change scenarios. It will be used to assess surface water availability for agriculture in the near and far future.  This information, which we generate using the physically based hydrological SWAT (Soil & Water Assessment Tool) model, will further be used by other project partners to estimate groundwater level declines and groundwater abstractions for irrigation purposes to generate a comprehensive picture of future water resources dynamics in the LCC area.

Current Results
A hydrological model (SWAT) was set up for the LCC area. Focus was put on modelling the changes of evapotranspiration rates as a proxy for changes in future water demand caused by changing land use patterns, alternative crop management strategies, and climate change scenarios. Remote sensing and ground station evapotranspiration measurements were used to calibrate and validate the model. Results show that optimized irrigation techniques examined in M2 can help to reduce irrigation water demand in LCC area by up to 20%.  A soft-coupling of the SWAT model with M4 groundwater model is under discussion.

Expected Outcome
M3 will be able to estimate the impacts of locally occurring environmental changes on future surface water availability in LCC. Reducing water demand by crop shifting according to local climatic patterns and climate change scenarios are currently assessed.