While SO₂ and NO_x emissions from energy, industrial and mobile sources have been reduced significantly by traditional regulations, land use-related emissions are playing a more dominant role in affecting surface water acidification through deposition. Development of land use and climate-based policies to improve both air and water quality requires comprehensive assessments of future deposition and meteorological conditions and its associated impacts on water quality, especially in sensitive regions (National Parks and other Class I regions). In this study, we applied the watershed biogeochemical model, PnET-BGC, to evaluate the responses of stream water chemistry to the future changes in atmospheric deposition and meteorological conditions in the Great Smoky Mountains National Park and the Adirondack region of New York in eastern US. The future atmospheric deposition scenarios were developed by using CMAQ model simulations of future (2050) scenarios with and without considering land use-related emission changes in various sectors (agriculture, biogenic and forest fire emissions). The future climate scenarios were extracted and downscaled from 18 global climate models from the Coupled Model Inter-comparison Project Phase 5 (CMIP5). Our simulation results will show that the difference in stream water chemistry in response to two future deposition scenarios (with and without land use-related emission change)  and the comparison of stream water chemistry in response to multiple projected meteorological conditions. Model simulations will examine the effects of changing climate and land use-related emission on recovery of stream waters.