Newaukum Creek Site 0322

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King County Water Quality Monitoring

King County monitors the ecological health of Newaukum Creek in a variety of ways including collecting and analyzing water, sediment, and benthic invertebrate samples. Since 1972 water quality samples have been collected 1 mile upstream from the mouth of Newaukum Creek at station 0322, located at the USGS gauging station near the bridge at 212th SE Street.

From time to time additional studies have been conducted at various streams in King County. Click here for information about Special Studies of Newaukum Creek.

Newaukum Creek Watershed

The Newaukum Creek watershed is located in South King County in Water Resource Inventory 9 (WRIA 9) and drains an area of approximately 27.8 square miles (Kerwin and Nelson 2000). The creek originates in the mountains east of Enumclaw Plateau, flows for roughly 14 miles, and enters the Middle Green River at River Mile 40.7. Eight tributaries to the creek provide and additional 13.5 miles of stream length.

Land use in the Newaukum Creek basin has gone from historic forested lands to agriculture and now to rural residential. The upland part of the basin (approximately 25 percent of the basin) was noted to consist primarily of commercial forest production in 2000 (Kerwin and Nelson 2000). This area is located outside the Urban Growth Boundary (UGB) and will likely remain in commercial forest production. The mid-section of the creek is known as the Enumclaw Plateau and consists of agriculture (pasture), low-density residential, and low-to-high density residential and commercial land uses. The Enumclaw Plateau area occupies approximately 57 percent of the basin.

For more information about the Newaukum Creek watershed, visit the WRIA 9 website for the Middle Green River Subwatershed.

Fisheries

Chinook, coho, sockeye, and chum salmon as well as winter steelhead have been observed spawning in Newaukum Creek (Kerwin and Nelson, 2000). Resident and Anadromous cutthroat have been observed throughout the basin. This subbasin of the Green-Duwamish watershed is considered to be a major producer of winter steelhead, coho and chinook salmon. The Middle Green River Baseline Habitat Survey Report provides more detailed information about habitat conditions in the Newaukum Creek area.

Water Quality

Water quality samples are analyzed monthly for temperature, dissolved oxygen, pH, conductivity, turbidity, total suspended solids, ortho-phosphorus, total phosphorus, ammonia, nitrate-nitrogen, total nitrogen, and fecal coliform bacteria. Results are compared to State water quality standards. Water quality standards are designed to protect public health and aquatic life. Comparing monitoring results to water quality standards allows an understanding of how safe the creek is for recreational contact as well as for aquatic life. (See link at top of page to view current water data.)

State water quality standards were revised in 2003. Newaukum Creek was considered a “Class A” water body under the 1997 rules. As the 2003 become effective Newaukum Creek is categorized as “Core Summer Salmonid Habitat” for aquatic life use, and “Primary Contact” for recreational use. As part of the updated water quality standards, Newaukum Creek has been assigned an additional “Supplemental Spawning and Incubation Protection” temperature criteria of 13 ºC to be applied from September 15th through July 1st. The creek is on the 2004 Washington Department of Ecology’s (Ecology) 303(d) list for violation of fecal coliform bacteria standards. See Table 1 for a summary of water quality violations in the creek during the most recent water year.

Water quality conditions in Newaukum Creek have historically been characterized as “fair” (Metro 1989) due to high nutrient concentrations and high fecal coliform bacteria counts related to agricultural practices.

Long-term Trends

A 25-year (1979 – 2004) trend analysis was conducted with baseflow water quality data collected from the mouth of Newaukum Creek. This analysis shows that there have been some improvements in water quality since 1979. Total suspended solids, ammonia, total nitrogen, and fecal coliform bacteria have all shown a significant decrease in this 25-year time period. pH values have shown a significant decreasing trend. However, conductivity and phosphorus concentrations (both ortho-phosphorus and total phosphorus) have increased significantly during this same time period and pH levels have lowered. In spite of improvements noted since 1979, a water quality data assessment conducted for the Green-Duwamish River in 2003 found that Newaukum Creek continues to have low dissolved oxygen and high nitrate-nitrogen, total nitrogen, ortho-phosphorus, total phosphorus concentrations in both base and storm flow, particularly at sites representing agricultural land use, relative to the rest of the Green-Duwamish watershed (Herrera 2005). Turbidity and total suspended solids were elevated in the creek during storm events. Total aluminum concentrations exceeded U.S. EPA chronic criterion during base flow sampling, and acute criterion during storm flow sampling.

Water Quality Index

A Water Quality Index (WQI) rating system was developed by the State Department of Ecology that evaluates several water quality parameters and gives a single rating of “high,” “moderate,” or “low” water quality concern. During the last six water years Newaukum Creek rated “moderate concern” primarily due to high FC and high nutrient concentrations. To see how Newaukum Creek ratings compare with other stream sites, visit the WQI page.

A review of the 2008 data shows the following violations of State water quality standards:

 

Hydrology

King County maintains ten water temperature gauges on Newaukum Creek at 305th Ave SE (44H), 212 Ave SE (GRT09), SE 424th St (GRT11), 292nd Ave SE bridge (GRT12), Newaukum Cr @ SE 416th (GRT24), Spring Creek (GRT25), Newaukum Cr @ SE 244th (GRT26), Newaukum Cr @ SE 248th (GRT27), North Fork Newaukum @ 292nd Ave (GRT28), and Newaukum Cr @ SE 416th & 278th (GRT29)

Stream Sediment

Sediment data were collected from Newaukum Creek as part of the Streams Monitoring program starting in 1987. Data were compiled and analyzed for the years 1987 through 2002. Data were analyzed for trends, correlations, and were compared to sediment quality guidelines. No significant trends were identified during data analysis for any of the parameters tested. Results indicate that Newaukum Creek sediments did not exceed any sediment quality guidelines. Of the 27 streams monitored in King County, Newaukum Creek had the 4th lowest metals concentration.

Benthic Invertebrates

The County also monitors stream health by collecting samples of benthic invertebrates from selected streams as part of King County's Benthic Invertebrate Program. Benthic invertebrates are an important link in the food chain for fish in the creek and are an excellent indicator of stream health. In both 2002 and 2003, benthic invertebrate samples were collected, analyzed, and benthic invertebrate index scores (BIBI) were calculated for Newaukum Creek. Each year several samples were collected from the creek.

Results indicate that conditions for benthic invertebrates in Newaukum Creek ranged from good to poor depending where on the creek the sample was taken. In general, the further downstream and closer to the Green River, the lower the score. Higher in the basin the samples had a lower percentage of species that are tolerant to degraded conditions, while lower in the basin the samples were dominated by these species. Also, higher in the basin there were several individuals of species that are long lived or are intolerant to degraded conditions. Whereas, in the samples from closer to the Green River very few individuals that are long lived, or are sensitive to degraded conditions, were present. Longer-lived species tend to take longer to reproduce and along with sensitive species, are among the first to disappear when a stream ecosystem is altered by human activity such as urbanization.

Special Studies

Green-Duwamish Water Quality Assessment

In 2001 King County initiated a separate comprehensive study of the Green-Duwamish Watershed, called the Green-Duwamish Watershed Water Quality Assessment (GDWQA). Several reports evaluate data collected as part of the GDWQA. Newaukum Creek is included in this analysis. More information about the GDWQA, as well as the reports, can be found at GDWQA page.