Projections of land cover change and its implications for water yield in the Maros watershed

The decline in water yield in the Maros watershed, which is located in the Mamminasata national strategic area, is influenced by land cover changes that occur in response to development in the watershed. The aims of this study are (1) to project future land cover changes (2032) via the CA-ANN approach and (2) to analyze the effects of these land cover changes on water yield via the SWAT model. In the SWAT simulation, the land cover map of 2023 and the projection map of 2032 were used as scenarios. SWAT-CUP was also used to validate the SWAT model. River Batubassi and River Lekopancing had R2 values of 0.7257 and 0.7802, respectively, indicating that the model worked well. The land cover change projections showed a decrease of 208.55 hectares of secondary forest and a decrease of 104.99 hectares of secondary mangrove forest, respectively. Additionally, the areas of settlements, fish ponds, paddy fields, and agriculture/crop land increased by 87.19 hectares, 95,79 hectares, 86.59 hectares, and 94.38 hectares, respectively. The SWAT simulation revealed that the water yield decreased from 31.09 billion m³ in 2023 to 21.65 billion m³ in 2032. A decrease in annual rainfall and a decrease in vegetated land area triggered a decrease in water yield.