The City's new innovative stormwater treatment facility provides an excellent opportunity to quantify the benefits of such a system on a variety of water quality parameters. Valuable information regarding how these parameters affect other related issues such as aquatic species and terrestrial wildlife can also be gathered from this treatment facility. An intensive monitoring strategy was initiated in 1999, prior to the commencement of construction. Post-construction monitoring was conducted through the 2002 calender year. The final water quality monitoring report is now available. This project will serve as a model to address use impairments related to non-point source pollution, habitat degradation and the coupling of these concerns with land uses.

The City of Portage has received a Section 319 Watershed Grant from the Michigan Department of Environmental Quality to help monitor this facility. This grant has also funded educational signage throughout the facility and long-term tracking of wetland plantings.
Prior to construction, two Isco Auto-sampling devices were stationed upstream and downstream of the stormwater treatment facility. Both instruments were used to log water level and collect water samples during wet-weather events. The water samples collected were sent to the Michigan Department of Environmental Quality laboratory for analysis of metals, total phosphorus, ortho-phosphorus, total kjeldahl nitrogen, nitrate & nitrite, ammonia-nitrogen, sodium, chloride, total suspended solids, and hardness. Each of these parameters can then be plotted against a water level hydrograph. An example of such a graph is shown below.
The figure at right displays upstream and downstream level as well as precipitation. The stars in the figure designate sampled events. As shown in the graph, a wide variety of precipitation events have been sampled during July through October, 2000.
Manual measurements of flow were taken in the drain during wet-weather events. These flow measurements were regressed with the corresponding water level. This relationship has been used to derive flows in the drain from instrument-measured water levels. An example of the regression relationship used to determine flow is shown in the figure below.
With an understanding of flows, pollutant loading can be calculated for each of the sampled parameters. An example of the loading graphs can be viewed in the figures to the right and below. Such calculations will continue to be made through 2002 to monitor the efficiency of this new stormwater treatment facility.