Flow Simulation and Storage Assessment in an Ungauged Irrigation Tank Cascade System Using the SWAT Model

In the semi-arid regions of South Asia, tank systems are the major source of irrigation. In India, the Telangana state government has initiated the Mission Kakatiya program to rejuvenate irrigation tank systems. Understanding the hydrological processes that supply water to these systems is critical to the success of these types of programs in India. The current study attempted to comprehend the hydrological processes and flow routing in the Salivagu watershed tank cascade system in Telangana. There are a lot of ungauged tank cascade systems in this region. Soil Water Assessment Tool (SWAT), a physically-based model, was used to simulate flow patterns in the Salivagu watershed with and without tank systems. The geospatially extracted area and volume were used for this study provided by WBIS-Bhuvan-NRSC. Additionally, the Katakshapur Tank Cascade System (KTCS) was chosen to analyze the water availability in each tank using the water balance approach. The Salivagu watershed flow simulation without tanks overestimated streamflow. The volume difference in flow between with and without tank was 606 Mm(3), 615.9 Mm(3), and 1011 Mm(3) in 2017, 2018, and 2019, respectively. The SWAT simulated volumes of the Ramchandrapur and Dharmaraopalle tanks in KTCS were merely satisfied because the tank size was less than 0.7 km(2) and the storage capacity was up to 1 Mm(3). Due to tank sizes more than 0.8 km(2) and capacities greater than 2 Mm(3), the Mallampalli and Katakshapur tank simulation findings were in good agreement with WBIS-Bhuvan-NRSC. This research advances our understanding of the hydrological processes in ungauged cascading tank systems in tropical semi-arid regions.

Automated summary

This study aimed to investigate the hydrological processes and flow routing of tank systems in the semi-arid region of Telangana, India. The SWAT model was used to simulate flow patterns in the Salivagu watershed, and water availability in the Katakshapur Tank Cascade System was analyzed using a water balance approach. The research found that tank sizes in the KTCS with areas less than 0.7 km(2) and capacities up to 1 Mm(3) were barely satisfied in the simulation.