Resolution No. 4793 - Laserfiche WebLink

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MWMC FACIL~ES PLAN irrigation, livestock watering, anadromous fish passage, salmordd fish rearing and spawning, resident fish and aqualSc life, w~ldlife and hunting, fishing, boating, water contact recreat/on, aesthet/c quality, and hydro power. Applicable water quality standards for the Willamette River that protect these uses are found in OAR 340 Division 41. In general the water quality of the Willamette River in Eugene-Springfield meets applicable standards, with a few exceptions. DEQ's "2002 List of Water Quality L/mired Waterbodies' (DEQ, 2002) indicates that the beneficial uses of the Willamette River are not entirely supported in the area of the discharge. The list indicates the WillameRe River violates [he in- stream standards for temperature in summer, mercury in fish tissue year-round, and also violates the human health criteria for arsenic. Temperature New revised Oregon water quality standards for temperature were recently approved by EPA. Included in the standards package are a series of maps that delineate the fish uses for water bodies in the state. According to these maps, [he Willamette River in the area of the WPCF discharge is listed as salmon and trout rearing and migration, and also as salmon and steelhead spawning from October 15 through June 15. This assignment of a spawning use to the Willamette River in Eugene-Springfield does not match other findings, including the recent Habitat AssessmentI. It may be a reflection of thinking that the area is a potential spawning area. Temperature criteria ha the new standards are expressed as 7-day-average maximum temperatures. The new criterion for salmon and trout rearing and rrdgration areas is 18 degrees Celsius (64.4 degrees Fahrenheit). The October 15 to June 15 spawrdng use has an associated temperature criterion of 13 degrees Celsius (55.4 degrees Fahrenheit), and this may be a future issue for fur[her noncompliance with standards, particularly in October during warm, dry fall periods. The temperature standard is violated in the Willamette River during the summer. Typical summer wastewater temperatures are in the low 70s Fahrenheit. The new Oregon temperature standard provides for a human use allowance along a specified reach of 0.3 degrees Celsius, and ut/lizing 25 percent of the 7Q10 stream flow assuming the stream temperature is above the numerical standard ~ercury The Willamette River in Eugene is included in the 2002 303(d) li~qt as not meeting water quality criteria for mercury in fish tissue. This listing is based on exceedances of the reference fish tissue value of 0.35 parts per million (ppm). The EQC is expected to act on DEQ's recommendations for changes to water quality criteria for toxic substances in the near future, and is expected to adopt EPA's recommended fish tissue criterion for methyl mercury of 0.30 ppm. Currently, DEQ is developing a mercury TMDL for the Willamette River. This TMDL is not expected to initially result in waste load alloca6ons for point sources, but rather to impose requirements for monitoring a~td implementation of mercury reduction plans. 1MECT, 2002. Aquatic and Riparian Habitat Assessment for the Eugene-Springfield Area, September 2002. 5-24 MWMO~5 0_REVS_VKS.[~