Keywords

irrigation water requirement; water balance model; irrigation tank; climate change

Location

Session H2: Water Resources Management and Planning - Modeling and Software for Improving Decisions and Engaging Stakeholders

Start Date

19-6-2014 10:40 AM

End Date

19-6-2014 12:20 PM

Description

This paper focuses specifically on the irrigation field and water supply tanks for ways to improve efficiency of water use and increase the resilience to climatic variability. The purpose of this paper is to develop an excel-based water balance model that will allow the maximum cropping area be planted in the upcoming agricultural season. The model consists of three modules: a crop water requirement calculator that allows the water requirements of specific crops to be compared, a water tank balance model, and a model which simulates the storage in the permanent wetland attached to the irrigation tank. The hydrological computation has been used with either daily rainfall data or predictions on water of availability for the upcoming agricultural season.

Climate change is predicted to further increase irrigation water requirements on the East Coast of Sri Lanka. Modelling shows a reduction of 26-45% in the area available to be cultivated due to increased irrigation water requirements and reductions in water availability. A number of scenarios have been investigated that increase the resilience of Sri Lankan farmers to climatic variations. Crop diversification decreases water requirements as crops other than rice don't require the maintenance of standing water. This significantly reduces the loss of water through seepage and percolation. Modelling shows that by substituting half the rice cultivated with maize, cropping area can be increased by 50%. Starting the irrigation season early proved the most successful measure and allowed cropping area to be increased by approximately 100% while having the irrigation tank and permanent wetland at 97% and 74% full respectively at the end of the first cultivation season.

 
Jun 19th, 10:40 AM Jun 19th, 12:20 PM

Development of a decision support tool to allocate irrigation water on competitive basis: application to Kathiraveli Village, Sri Lanka

Session H2: Water Resources Management and Planning - Modeling and Software for Improving Decisions and Engaging Stakeholders

This paper focuses specifically on the irrigation field and water supply tanks for ways to improve efficiency of water use and increase the resilience to climatic variability. The purpose of this paper is to develop an excel-based water balance model that will allow the maximum cropping area be planted in the upcoming agricultural season. The model consists of three modules: a crop water requirement calculator that allows the water requirements of specific crops to be compared, a water tank balance model, and a model which simulates the storage in the permanent wetland attached to the irrigation tank. The hydrological computation has been used with either daily rainfall data or predictions on water of availability for the upcoming agricultural season.

Climate change is predicted to further increase irrigation water requirements on the East Coast of Sri Lanka. Modelling shows a reduction of 26-45% in the area available to be cultivated due to increased irrigation water requirements and reductions in water availability. A number of scenarios have been investigated that increase the resilience of Sri Lankan farmers to climatic variations. Crop diversification decreases water requirements as crops other than rice don't require the maintenance of standing water. This significantly reduces the loss of water through seepage and percolation. Modelling shows that by substituting half the rice cultivated with maize, cropping area can be increased by 50%. Starting the irrigation season early proved the most successful measure and allowed cropping area to be increased by approximately 100% while having the irrigation tank and permanent wetland at 97% and 74% full respectively at the end of the first cultivation season.