Spatial Variability of Stormwater Control Measures in Northeast Ohio: Preliminary Analysis and Additional Data Required04/15/2020
In urban areas, impervious surfaces and pipe networks rapidly deliver high volumes of stormwater to streams and sewer networks. Stormwater runoff causes flooding, erosion, pollution and degradation of aquatic ecosystems, and the discharge of raw sewage into the environment when combined sewers overflow. These impacts, especially in the context of increased urbanization and climate change have provoked intense interest in mitigating stormwater runoff. Yet, the impact of stormwater management practices on urban hydrology is poorly understood at the watershed scale as well as at the scale of a metropolitan area. Increased urbanization and imperviousness in urban watersheds throughout the world necessitate informed decision-making practices when implementing stormwater control measures. This study seeks to quantify how stormwater management actions modulate the influence of urbanization on flow regimes at the watershed scale. We analyze impervious surface cover and road density as measures of urbanization intensity. Based on data provided by the Cuyahoga Soil and Water Conservation District for 22 municipalities, the density of SCMs in USGS gauged watersheds is 0.31 SCMs/km2. Incomplete data means that this number is likely and underestimate of the true SCM density in the Cleveland area and we are actively seeking additional sources of SCM data from municipalities and other organizations. Using the current SCM dataset, we analyze the variability in SCM types, year of construction, and spatial distribution and compare these results to urbanization intensity. Once the SCM database is complete in the >12 USGS gaged watersheds in the Cleveland area, the next step will be to analyze the hydrologic response to precipitation with respect to urbanization intensity and stormwater management and their change over time. This research has the potential to inform municipal and watershed-scale efforts to optimize investments in stormwater infrastructure.