Nutrient enrichment is a ubiquitous stressor to freshwater ecosystems. In order to effectively manage freshwater ecosystems, we need a better understanding of spatiotemporal dynamics of water chemistry at multiple spatial scales. We used a long-term dataset (27 years) of watershed-scale synoptic sampling of two rivers nationally recognized for their aquatic biodiversity, the Etowah and Conasauga Rivers. Water quality monitoring programs were initiated in both rivers in 1997, with synoptic sampling continuing through 2025 at frequencies ranging from one to ten times per year. We evaluated watershed controls on spatiotemporal patterns in nutrients and conductivity. Preliminary analyses revealed that nitrate and SRP concentrations declined modestly but significantly over time in both the Etowah (β = −0.028 ± 0.007 SE yr⁻¹, p < 0.001; β = -0.069 ± 0.009 SE yr⁻¹, p<0.001) and the Conasauga (β = -0.029 ± 0.007 SE yr⁻¹, p<0.001; β = -0.051 ± 0.007 SE yr⁻¹, p<0.001). However, temporal stability at the watershed scale does not preclude substantial spatial heterogeneity within watersheds. Watershed-level analyses may obscure important variation occurring at the subcatchment scale. Spatially distributed sampling therefore provides a critical opportunity to test the spatial scales which may be controlling nutrient fluxes and to identify areas that exert disproportionate influence on watershed-scale nutrient dynamics. To address this, ongoing analyses integrate long-term water quality data with land-use change information and subcatchment leverage calculations to examine how nutrient sources and sinks within subcatchments influence flux at watershed outlets. Additionally, leverage analyses allow for the identification of specific subcatchments that function as biogeochemical control points. Comparing patterns between rivers with differing geology and land-use histories may further reveal common small-scale drivers that shape watershed-scale nutrient behavior. By identifying the location and spatial scale of these control points, this work provides spatially explicit frameworks for the focal watersheds which could improve the efficiency of monitoring programs and help inform targeted management and conservation strategies.