Urbanization and watershed development have often been driven by an increased demand for food and livelihood. However, developments upstream may cause changes in nutrient fluxes discharging to the receiving water body, such as a lake, and trigger a decline in water quality. Tinago Lake, located within Batan Bay in Aklan, Philippines, is known for its very productive aquaculture and diverse aquatic resources but has been experiencing lower productivity over years of urbanization and watershed development to cater to the community's needs. As developments in the catchment upstream affect the ecosystem dynamics downstream, understanding the impacts of these developments on the receiving water body is essential for sustainable watershed-lake management initiatives. This study aims to investigate the effect of decadal land cover change on the nutrient discharges of Batan Watershed. The Soil and Water Assessment Tool+ (SWAT+) was used to describe the seasonal hydrology and nutrient fluxes of the watershed draining to Tinago Lake. A long-term scenario simulation to investigate the effect of land cover change on the nutrient outputs of the watershed was also done using the 1990, 2000, 2010, and 2020 land covers as input to the hydrology model. Land cover analysis showed that from 1990 to 2020, there was an 18.60% reduction in agricultural cover while having an increase of 11.85% and 53.16% in rangelands and forests, respectively. Long-term simulation results showed that about 41.29 kg of nitrogen and 3.07 kg of phosphorus from the watershed are added to the load discharging to the lake each year. In addition, model results revealed a general increase in carbon yield, with drops observed during El Niño years, indicating the pronounced effect of precipitation on the carbon yield of the catchment. Lastly, an annual average increase of 2895.4 tons of carbon for the past 30 years was calculated which can be related to the amount of sediments coming into the bay that is affected by the land cover in the upstream catchment. The information generated from this study could aid local stakeholders in planning future development for both the lake and watershed and assess its possible impacts on the water quality of the receiving water body.