Water accounting and auditing assessment
Due to the effects of climate change, such as prolonged droughts and floods, farmers in the Malwathu Oya southern catchment are experiencing challenges with the water supply. To improve water resource management, especially in times of water scarcity, the KnoWat project set out to conduct a water accounting and auditing (WA&A) assessment in the Malwathu Oya southern catchment.
Water accounting and auditing are an essential aspect of managing water resources. Water accounting is the systematic examination of status and trends in the availability, demand, accessibility and usage of water. Water auditing puts trends in water supply, demand, accessibility, and usage into a broader framework of governance, institutions, public and private expenditure, law and the political economy of water. When combined, water accounting and auditing facilitate policy development and decision-making.
In addition to the water accounting and auditing assessments, the KnoWat project carried out a water productivity study in an area found to have low water productivity .
The water accounting study focused on ten subwatersheds of the Malwathu Oya catchment over four seasons. In each case, water balances were calculated with inputs from the WaPOR database, based on the Soil and Water Assessment Tool (SWOT), which is commonly used for hydrological studies by the Irrigation Department of Sri Lanka. These water balances were compared with observed hydrological data. The study showed that the flows based on the SWOT and WaPOR data were between 4 and 13 percent higher than the observed flows. It concluded that the model replicates the situation on the ground quite well and can be used in future water balance studies.
The water auditing study focused on three case studies in areas where there is an issue with water management:
- Water sharing between agricultural and domestic uses and the issues of unavailability of water from a tank in Thuruwila . The auditing study discovered that enhancing collaboration between area officials and the farmers could help solve issues related to water sharing by drawing on the practical knowledge of the farmers.
- The Nuwara Wewa feeder canal and the issue of illegal use of water. In this case, irrigation officials believe that the illegally-irrigated lands should be legalized because siphoning is difficult to control.
- Water management in areas of low water productivity in the Nachchaduwa irrigation scheme. The water productivity analysis (see below) revealed inadequate maintenance and cleaning of the canal, which caused flooding and, as a result, low water productivity. In addition to improving the canal system, the establishment of better facilities for accessing and using the infrastructure should be considered.
The results of the water accounting and auditing studies were validated with stakeholders at local and national levels. The information can underpin better decisions on water management in the future.
Capacity building
In cooperation with the International Water Management Institute (IWMI), the KnoWat project trained 30 experts from the Irrigation Department of Sri Lanka and other partners in water accounting and auditing methodologies through a combined on-site and remote training programme. In addition, 23 experts were trained in the application of WaPOR data to assess agricultural water use and productivity at basin and irrigation scheme levels.
In cooperation with the University of Peradinya, students and university staff received training in WaPOR-based water accounting and productivity assessments. WaPOR-based assessments have now been incorporated into the curricula of hydrology and agronomy students.