Home | Overview | Willamette bathymetric survey | Dye studies | Width survey | N. Santiam temperature model
In 2002, the U.S. Geological Survey (USGS) began an investigation of water temperature in the North Santiam and Santiam Rivers in western Oregon. This effort included the development of a flow and temperature model of those rivers, starting at Big Cliff Dam and ending at the mouth of the Santiam River where it joins the Willamette River. This work was performed in an effort to better understand, quantify, and model those processes that determine stream temperature. This project also was undertaken in support of efforts by the Oregon Department of Environmental Quality (ODEQ) to generate water temperature Total Maximum Daily Loads (TMDLs) to comply with the Federal Clean Water Act.
The ability of many streams in the Willamette River Basin in northwestern Oregon to support resident fish and aquatic life, salmonid fish spawning, and salmonid fish rearing is impaired by water temperatures that often are too warm. Water temperature is the most frequently listed criterion on the State of Oregon's 1998 list of "impaired" waterbodies (the 303(d) list), accounting for 87% of the total length of listed streams in the State. In addition, many streams in the Willamette River Basin are listed for threatened and endangered salmon and steelhead species under the Federal Endangered Species Act, and one of the issues threatening these species is an excessively high water temperature.
By the end of 2003, ODEQ is required to finalize and submit to the U.S. Environmental Protection Agency a TMDL for water temperature in the Willamette River and many of its tributaries. This TMDL will specify certain remedies necessary to restore the water temperature of these rivers to a regime that is healthier for fish. To ensure that the temperature TMDL is based on a sound foundation, ODEQ put together a team from industries, municipalities, and local, state, and federal agencies to collect temperature data and construct the necessary temperature models. The USGS is a member of that team, and this project was undertaken to strengthen the Willamette TMDL process.
To aid in the development of a Willamette temperature TMDL, USGS personnel identified several tasks that would strengthen ODEQ's efforts to analyze and simulate water temperature and subsequently develop TMDLs for these rivers. These tasks were critical to the success of the TMDL modeling effort.
USGS personnel collected detailed bathymetric data, both cross-sections and a longitudinal mid-channel transect, in the main stem Willamette River. These data were needed to fill a large data gap so that an accurate representation of the geometry of the Willamette River channel would be available to the scientists at Portland State University that were constructing a numerical model of flow and water temperature in the Willamette River.
USGS personnel conducted four dye studies to determine travel time in selected river reaches of the Willamette and Long Tom Rivers. Two dye studies were conducted on each of these rivers; one at high flow in the spring, and one at low flow in late summer. Dye studies provide important information on the time of travel in the studied reaches. No such studies had ever been performed on the Long Tom River, so this work filled a data gap. For the other rivers, travel time data were available from a comprehensive 1960s era study by Harris (1968). The dye studies on the Willamette River were used to verify that the Harris data were still valid.
USGS personnel performed surveys of river width along the lengths of the largest Willamette River tributaries. These rivers included the Clackamas, North Santiam, South Santiam, Santiam, McKenzie, Blue, South Fork McKenzie, Middle Fork Willamette, Coast Fork Willamette, and Row Rivers, as well as Fall Creek, from their mouths up to the first major dam. These data were critical to the calibration of the flow and water temperature models being constructed for the temperature TMDL analysis.
USGS personnel participated on ODEQ's Willamette River TMDL Model Coordination Team (MCT), which oversaw all aspects of model construction, calibration, and use. USGS personnel also were involved in all details of the modeling work through the construction of a flow and temperature model for the North Santiam and Santiam Rivers, one of the rivers included in the Willamette temperature TMDL.
This investigation enhanced our knowledge of the water resources of the region by providing the data and supporting/developing the analytical methods necessary to understand the dynamics of water temperature in western Oregon streams. Warm streamwater is one of the most important issues facing management and regulatory agencies across Oregon and Washington because warm streamwater is detrimental to native aquatic life, resident fish, and the rearing and spawning needs of anadromous fish. Providing reliable scientific data and interpretations that are essential for the sound management of the Nation's water resources is one of the primary missions of the USGS; this investigation supported that mission and is relevant well beyond the boundaries of the Willamette River Basin.
The goals of this investigation are consistent with actions identified in the USGS Strategic Plan and the Strategic Directions document for the USGS Water Resources Discipline. One of the thrusts identified in the USGS Strategic Plan is to enhance our predictive modeling capabilities. One of the goals identified in the Strategic Directions document is to "design study products that will be more useful and relevant to solving problems that are faced by water managers and other decision makers," including "the development of models and other decision-support tools, including evaluation of alternative management scenarios, in interpretive and assessment studies." This study helped to fulfill these identified goals.
To meet the objectives of this study, bathymetric and travel-time data were collected, and a numerical model of water temperature was constructed and calibrated for one of the tributaries to the Willamette River.
Detailed cross-sectional and longitudinal depth-profile data, referenced to a reliable elevation datum, were collected in the main-stem Willamette River from Harrisburg (approximately) to the Willamette Falls, focusing on reaches where previously collected HEC-2 cross-sectional data were not available. In this manner, this work identified all of the shallow and deep areas of the river channel, allowing interpolated cross-sections to be created for the model grid that capture these depth characteristics of the channel. Cross-sectional data were collected approximately every mile along the profile of the river, using standard protocols with an acoustic doppler current profiler. Detailed streamflow measurements were collected at the same time, every 3 to 5 miles. All data were referenced to an elevation datum using advanced Global Positioning System (GPS) and surveying techniques. These data were collected during the winter of 2002.
Because the width of the river is critical in determining the amount of solar energy received by the river, USGS personnel visited as many sites as practicable (one per mile, when possible) along the lengths of the major tributaries (Clackamas, North and South Santiam, McKenzie, Middle Fork, and Coast Fork) to measure the surface width of the river. These visits were done three times each, at different levels of streamflow (April, June, and August). Such width data provide an important check for the temperature calibration of the model.
Dye studies were performed on both the Long Tom River and on a 25-mile (approximate) reach of the main stem Willamette River, to verify the accuracy of an older, but more comprehensive travel-time dataset from the late 1950s and early 1960s. Dye studies were carried out at two different flow levels (spring and late summer). Standard techniques and rhodamine WT dye were used.
As part of the USGS effort supporting the Model Coordination Team, USGS personnel attended monthly MCT meetings that discussed all aspects of model construction, calibration, and use. To ensure a real depth of involvement in the modeling work, as well as the construction of a product that could be published, USGS personnel constructed and calibrated the temperature model for the North Santiam and Santiam Rivers, one of the Willamette River tributaries included in the TMDL effort. Like all the other models constructed by Portland State University and ODEQ for the Willamette temperature TMDL work, the North Santiam and Santiam River models were constructed using CE-QUAL-W2, a Corps of Engineers flow and water quality model. Initial model calibration was accomplished with a dataset from 2001; further calibration and verification of the model used data from 2002. A USGS report was prepared that describes the construction, calibration, and use of the temperature model.
Cole, T.M. and Wells, S.A., 2000, CE.QUAL.W2: A two-dimensional, laterally averaged, hydrodynamic and water quality model, version 3.0: U.S. Army Corps of Engineers Instruction Report EL-00-1 [variously paged].
Harris, D.D., 1968, Travel rates of water for selected streams in the Willamette River Basin, Oregon: U.S. Geological Survey Hydrologic Investigations Atlas HA-273, 2 sheets.
Oregon Department of Environmental Quality, 1998, Oregon's 1998 water quality limited waterbodies - 303(d) list [Online], URL: http://www.deq.state.or.us/wq/WQLData/SearchChoice98.htm, accessed January 14, 2004.
U.S. Geological Survey, 1999b, Strategic directions for the Water Resources Division, 1998-2008, U.S. Geological Survey Open-File Report 99-249, 19 p.
Home | Overview | Willamette bathymetric survey | Dye studies | Width survey | N. Santiam temperature model
Questions? Comments? For more information about this project, contact:
Stewart Rounds
U.S. Geological Survey
2130 SW 5th Avenue
Portland, OR 97201
503-251-3280
sarounds@usgs.gov
Oregon Water Science Center Home page
Oregon Water Science Center Hydrologic Studies page
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