Harvesting Nature's Bounty: Leveraging Flood Water Diversion for Sustainable Agriculture and Pisciculture in Wetlands

Abstract Lakhimpur district extensive river system has been prone to flash floods, causing devastation every year. In the district, wetlands are disappearing at an alarming rate, covering a large part of the land surface. To achieve a reduction in flood magnitude, it is important to investigate the feasibility of diverting flood water to existing wetlands. As a result, the study investigated flood mitigation measures, such as the diversion of floodwater into existing wetlands. LiDAR-DEM was used to determine the capacity of suitable wetlands. An embankment along their edges was constructed to increase their capacity and prevent them from overtopping. To divert flood water, LiDAR-DEM was used to identify suitable routes, and canal sections were designed along those routes using Lacey’s Regime theory. Estimating peak flood discharge in rivers was done using HEC-HMS hydrological modeling software. In-situ Sediment load calculation was carried-out. AHP model was used to identify the suitable sites for Check-dam construction as a controlling measure. Crops that can be grown during non-monsoon seasons were recommended for use of wetland water. Using the Crop Water Requirement for the respective crops, the water availability in the wetland was evaluated. The findings demonstrate that the peak river discharge exceeds the capacity of wetlands, and it is additionally evident that the flow of silt will quickly fill wetlands. Flood water diversion into existing wetlands will not be feasible since it would be unsustainable and expensive. However, economic analysis shows that utilizing wetlands water for irrigation and pisciculture may lead to positive economic growth.