Serial Correlation Characteristics of Hydrology and Water Quality From Stormwater Management Technologies

Natural stream system state variables (flow, temperature, dissolved oxygen, etc.) possess varied stochastic properties from site to site. The majority of land development occurs on smaller order streams (first, second). Because stormwater management is often required with development, yet specific strategies are not prescribed, often the selected technologies may solve one problem (for example flood peaks) yet cause another (for example, retention ponds increasing summer temperatures). In small order streams, the effluent from stormwater management technologies can dramatically affect the background stochastic characteristics receiving stream. This study selected variables measured in real time (flow, temperature, conductivity, pH, and dissolved oxygen), over a three year period, and determined the serial correlation characteristics of these variables in the influent and effluent from the following stormwater management technologies: grass swale, rip rap swale, retention pond, sand filter, bioretention cell, and gravel wetland. The results underscore the differences that these technologies imprint on their effluent. Ultimately, this information should lead to improved decision-making in the selection of stormwater management technologies that flow into small order streams.