Frequently Asked Questions
What is a watershed?
A watershed is the entire area draining into a specific body of water,
such as a river or creek. Watersheds are composed of uplands,
riparian areas, wetlands, lakes, streams, and rivers. One
watershed is separated from another by ridgetops.
How big is the Tualatin Watershed?
It is 712 square miles (455,680 Acres)
The Tualatin River is approximately 83 miles long and flows from the
eastern side of the Coast Range to the Willamette River.
The Tualatin River is a fourth-field
hydrologic unit (HUC 17090010)
What type of climate does the watershed have?
Mediterranean
climate with prolonged winter rainfall and summer drought
Mean winter air temperatures in the valley floor |
32º F to 63º F (0º C to 17º C) |
Mean summer air temperatures in the valley
floor |
41º F to 83º F (5º C to 28º C) |
Rainfall varies from 100” to 120” in the Coastal Range
to 48” to 36” in the valley (inches per year)
What are the major and minor tributaries?
Major |
Minor |
- Scoggins Creek
- Gales Creek
- Dairy Creek
- Rock Creek
- Fanno Creek
|
|
Are there any reservoirs in the watershed?
Scoggins Reservoir (Henry Hagg Lake)
Barney Reservoir on the Trask River releases water to the Tualatin
River during the summer months.
 Where is the Tualatin River Watershed located?
Most is in Washington County
Small sections are in Clackamas, Tillamook, Multnomah, Columbia, and
Yamhill counties
How do I find out the current flow of the river?
The river’s
flow is measured in cubic feet per second (cfs) and can
be found at these sites: US Geological Survey (or.water.usgs.gov/ )
and the watermaster.
What Cities are located in the Tualatin Watershed?
Banks, Beaverton, Cornelius, Durham, Forest Grove, Gaston, Hillsboro,
King City, North Plains, Sherwood, Tigard, Tualatin, West
Linn. A large portion of the urbanized area is in unincorporated
Washington County.
 What is the population of the Tualatin Basin?
-
Approximately 450,000 (US Bureau of Census, 2001)
-
Washington County has grown 43 % in the last 10 years
What are the predominant uses of the land in the Tualatin Watershed?
-
15% Urban
-
35% Agriculture
-
50% Forestry
Who owns and/or manages the land?
What are the water quality issues?
The Department of Environmental Quality issued Total
Maximum Daily Loads for Dissolved Oxygen (excess oxygen-consuming organics and ammonia),
Temperature, Bacteria, and Chlorophyll a (excess phosphorus)
for the Tualatin Basin in August 2001.
Are there species on the Endangered Species List in the Tualatin Basin?
Winter Steelhead are listed as threatened
What types of wildlife can be found in the basin?
Roosevelt elk, black-tailed deer, and black bears are found in the
Coastal Range
An estimated 5,000 Canada geese and 65,000 ducks winter in the basin.
Bald eagles, osprey, herons, hawks and many more birds live in the
basin.
 What are the recreational opportunities?
The Tualatin Riverkeepers have a recreation
guide.
There are many parks and trails.
Hagg Lake is open to boating and fishing. Many people enjoy canoeing
on the Tualatin.
What are the economic drivers in the Tualatin Basin?
Agriculture; horticulture; forest products; food processing; high-tech,
including software and electronics; sports equipment; and
apparel (Oregon Blue Book)
What is the economic productivity?
Washington County is ranked 4th in state for gross farm and
ranch sales with $204 million (Oregon Department of Agriculture
2001)
Washington County is ranked 2nd county in state for retail sales (US Census Bureau: 1997
Economic Census)
Per capita personal income $30,621 compared to Oregon average of $23,920
(1998 figures)
|
