Assessment of climate variability and short-term land use land cover change effects on water quality of Cahaba River Basin

This study examines the short-term impacts of land use land cover (LULC) changes as well as climate variability on the water quality of the Cahaba River watershed in Alabama. The Soil and Water Assessment Tool (SWAT), in combination with spatial-temporal analysis were applied for evaluating contributions of dominant LULC patterns on changes in the sediment yields and nutrient loads. Optimised hot spot analysis with LULC change alone showed decreases in sediment yield and nutrient loads in the upper Cahaba watershed where forests and agricultural lands were replaced by urban development. Climate and LULC raised annual sediment yield and phosphorus load by 2.8% and 61% respectively and lowered nitrogen load by 17%. The combined changes in climate and land use posed a stronger impact on water quality in future. The findings of this study will provide useful information for future water and land management in the Cahaba River Basin.