Comparison of Bacteria and Nutrient Loading in Subsurface Storm Drains Receiving Flows from Groundwater Seepage and Dry Weather Urban Runoff

摘要

This project examines whether there is a positive association between bacterial growth and nutrient loading in subsurface storm drains. Storm drains that are perennially fed by groundwater seepage and/or permanent dewatering infrastructure may provide "incubator" conditions for bacteria proliferation. Grout lined storm drains convey storm runoff and dry weather flows (car wash runoff, lawn runoff, and other nuisance flows) away from urban areas. As runoff enters storm drains, it carries N and P, which serve as electron acceptors and provides necessary energy for bacteria to multiply. Other elements needed to create incubator conditions are carbon rich input and seed bacteria. Vegetation detritus washed into the storm drain during urban watering or from internal algae growth provide a carbon source, and enough wildlife exists in and near storm drains (racoons, bats, rats) to provide the seed bacteria spawning bacteria growth.