Oral Presentation Society for Freshwater Science 2026 Annual Meeting

From Land to Lake: A Continuous Flow-Path Framework for Land-Use Impacts on Water Quality (134704)

Mikaela Sako 1 , Erich Seamon 1 , Thad Scott 2
  1. Environmental Science, Baylor University, Waco, TX, United States
  2. Biology, Baylor University, Waco, TX, United States

Land-use composition within a watershed is a critical driver of variation in water chemistry across waterbodies at a landscape scale. However, the magnitude of land-use effects may vary across climate gradients and along hydrologic flow paths. Here, we quantify land-use influences on lake water quality across Texas lakes using a continuous, flow-path based distance metric within hydrologically connected subwatersheds. Land-use data from the National Land Cover Database (NLCD) are integrated with routed flow paths to weight upstream land-use contributions by hydrologic distance from each lake. Statistical models are used to relate these metrics to observed nutrient and chlorophyll-a concentrations from Texas lakes monitored by the Texas Commission on Environmental Quality (TCEQ).  Generalized additive and mixed model approaches are used to quantify nonlinear land-use-water-quality relationships and examine how these relationships vary with climate conditions, spatial scale, and hydrologic context. The aim of this research is to improve inference on the land-use composition and water quality correlations by accounting for variation in spatial scale and hydrologic context.