The SPROut (Sustainable Plant Research and Outreach) program
at The Oregon Garden started collecting wetlands water quality
data in 2002, and since then has expanded to 14 designated sites.
We check monthly for nutrients (nitrate and phosphorous), temperature,
turbidity, conductivity, dissolved oxygen, and pH for each of
the 14 sites, and conform to DEQ standards. We take all measurements
on site except for the nutrient sampling which is sent to a Portland
lab for analysis.
Rough analysis of the water quality data shows a reduction
in nutrient load and temperature as the water filters through
the ponds. Our flow system using aquatic plants restores water
to acceptable standards for fish and watershed health before
rejoining the local watershed at Brush Creek.
Figure 1 shows a summary for several months of nitrate
data in 2005. It confirms a decrease in nitrate levels as the
water passes through the cells. A rough comparison between the
levels in the wastewater cells and those sites not influenced
by wastewater (Brush-Up, Native Pond, and Oak Grotto) demonstrates
that our wetlands return nitrate density to levels more characteristic
of native waters.