A detailed quality assurance project protocol governs all UNHSC’s methods, procedures, maintenance, and analyses related to the evaluation of stormwater treatment systems. All systems have an impermeable liner so that researchers can provide a strict accounting of the stormwater runoff flowing through the systems, as well as the contaminants it contains.

Mouse over the numbered steps in the diagram below for a description of the evaluation process.

Step 1

1. Stormwater runoff from the nine-acre parking lot is channeled into a 36-inch pipe where influent (runoff) is monitored in real time for the following characteristics: flow, pH, conductivity, dissolved oxygen, temperature, and turbidity. At the same time, automated samplers collect samples of influent at discrete time intervals over the course of the rainfall’s hydrograph. These samples are processed and evaluated for a range of contaminants, or frozen for future evaluation.

Step 2

2. Stormwater then flows into a distribution box with a floor that rests slightly higher than the outlet invert elevations, which direct runoff to each of the stormwater treatments. This configuration insures that runoff will scour the floor of the box, thereby preventing the accumulation of sediment. Baffles and flow splitters help to equally and evenly distribute stormwater among treatments.

Step 3

3. From the distribution box, runoff influent flows into a network of pipes and is distributed into each stormwater treatment.

Step 4

4. Runoff influent moves through the stormwater treatments.

Step 5

5. Runoff leaving the treatments (effluent) is conveyed by perforated subdrains into a sampling gallery.

Step 6

6. In the sampling gallery, the effluent is monitored in real time for the following characteristics: flow, pH, conductivity, dissolved oxygen, temperature, and turbidity. Also in the gallery, automated samplers collect samples of runoff at discrete time intervals over the rainfall hydrograph. These samples are evaluated for the same range of contaminants to generate performance characterizations.