Identification of suitable sites for freshwater aquaculture in the flood-prone areas of the Nilwala river basin, using land use patterns and soil quality

Abstract

Flood-prone areas (FPA) are land areas susceptible to being inundated by water and, preparation of FPA maps are important in disaster management and planning further development activities. The present study ascertains the areas suitable for aquaculture in flood-prone areas of the Nilwala River basin, using land-use patterns and soil quality. Five GIS maps of the most flooded District Secretariat (DS) divisions of Matara district, viz, Thihagoda, Malimbada, Athuraliya, Matara, and Kamburupitiya were developed. Relative abundance of sand, clay, and silt and the pH and electrical conductivity (EC) were measured. Basic soil textural classes were ascertained in 20 selected locations having high aquaculture potential. Developed GIS maps indicate that potential areas for aquaculture were highest in the Matara DS division (9.64 km2) followed by Thihagoda (6.25 km2), Athuraliya (2.13 km2), Malimbada (2.08 km2), and Kamburupitiya (1.53 km2) DS divisions, having a cumulative value of 21.63 km2, accounting for 22% of FPA in five DS divisions. Abandoned paddy fields (10.52 km2) accounted for the highest aquaculture potential areas followed by marshlands (7.38 km2), rivers and canals (2.6 km2), and minor reservoirs (0.59 km2).