Water Quality Monitoring
Sites
Jackson Bottom Wetlands Preserve — southern end of Preserve

Gene Pool Monitoring
Site
The "Gene Pool" is a restored
wetland pond on the Jackson Bottom floodplain. It is named after
Gene Herb, a retired wildlife biologist, who serves on the Preserve's
Board of Directors. The Gene Pool is located about 1/4 mile northeast
of the Education Center. The Gene Pool was constructed in 1998 to
provide open water habitat for ducks and other water birds. A water
quality station is maintained at the Gene Pool. In order to interpret
the water quality data, a basic understanding of the hydrology of
the Gene Pool is needed.
For much of the year the Gene Pool is
hydraulically separated from the rest of the floodplain. A low berm
holds water in the Gene Pool. Groundwater flow is generally low
due to the low permeability of the silt and clay soils. During the
summer, much of the Gene Pool dries out, exposing mudflats that
are used by shorebirds. The west portion of the Gene Pool, where
the water quality monitoring station is located, generally still
holds water during the drier months. During the summer there is
considerable growth of aquatic plants and algae.
Clean Water Services recycles treated
wastewater in the Gene Pool in late spring (May - June) and again
in fall (November - December). The treated wastewater is discharged
into the east side of the Gene Pool; the monitoring site is on the
west (opposite) side. In winter and spring, as a result of significant
precipitation events, the Tualatin River overflows onto large areas
of the Preserve, including the Gene Pool. At water levels above
approximately 129 feet above Mean Sea Level (MSL) , water flows
into the Gene Pool.
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Tualatin
River Monitoring Site
The Tualatin River drains an area of
712 square miles. The river generally flows in easterly direction
from its headwaters in the Coast Range to its confluence with the
Willamette River. The river is approximately 83 miles long, with
several tributaries, including Scoggins, Gales, Dairy, Rock and
Fanno Creeks.
Jackson Bottom Wetlands Preserve is
located in the 3000-acre Jackson Bottom floodplain of the Tualatin
River. Jackson Bottom is located just downriver of the Dairy Creek
confluence with the Tualatin. In winter and spring, as a result
of significant precipitation events, the Tualatin River overflows
onto large areas of the Preserve. Most of the Preserve is at 128-130
feet MSL (above Mean Sea Level). The water quality monitoring site
at the Preserve is at River Mile (RM) 44.4. (RM 0 is at the confluence
with the Willamette River.)
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