CRWC WQ Methods and Discussion


From 2010 through 2014, the Crooked River Watershed Council (CRWC) monitored water quality parameters in the Crooked River watershed that are essential to understanding threats to habitat quality. The monitoring is intended to raise awareness about where, and the degree to which water quality in the basin departs from desired standards. The monitoring is also designed to inform long term trend analysis, guide project priorities, and support ODEQ’s TMDL process. This reporting contributes to the goals of the Crooked River Watershed Council by communicating water quality conditions to stakeholders and partners in the watershed. The data is located on the council’s website and is fully accessible to any interested party.


The Crooked River Watershed consists of three 4th field sub-basins and covers nearly three million acres of public and private lands, these sub-basins are the Lower Crooked River, the Upper Crooked River, and the Beaver-South Fork Watershed. The Oregon Department of Environmental Quality’s (ODEQ) water quality assessment database lists 587 miles of 303d temperature-listed streams in the Crooked River Watershed. Conditions and land uses in the Lower Crooked River Watershed potentially impacting water quality include climate, the encroachment of Western Juniper (J. occidentalis), stored and diverted of water for irrigated agriculture, non-irrigated agricultural practices, urban and rural development, seasonal sewage treatment activities, logging, roads, and recreation. Stream channels characterized by unstable banks and disconnected floodplains also contribute to a decline in water quality.

Native redband trout (Onchorynchus mykiss) inhabit much of the Crooked River Watershed, and with the completion of a fish passage facility at the Pelton-Round Butte hydroelectric complex in 2008, Mid-Columbia summer steelhead (O. mykiss) and chinook salmon (Onchyrnchus tshawytscha) were actively reintroduced.

The Lower Crooked River

This subbasin is the entire drainage of the Crooked River below Bowman dam, approximately 1.2 million acres. Most of the subbasin is located in Crook and Deschutes counties in Central Oregon. The lower Crooked River encompasses a range of ecological conditions, from semi-arid areas of high desert prairie to moist forest. Landform is punctuated by small mountain ranges and isolated peaks, and include valleys, plains, foothills, headwaters streams, and rivers. Elevation ranges from a low point of 1942 ft. at Lake Billy Chinook to a high point of 5925 ft. located in the Ochoco National Forest between Little McKay and McKay Creeks. Communities within the watershed include Prineville, Terrebonne, parts of Redmond, and a portion of Culver.

The Lower Crooked River is located in the south-central Oregon climatic zone. The climate is characterized by cold nights throughout the year, and hot daytime summer temperatures. Average annual precipitation is between 8 and 15 inches at lower elevations, and may reach 30 to 40 inches at higher elevations in the Ochoco Mountains. Precipitation in the higher regions is typically in the form of snow during the winter months. The highest monthly precipitation totals occur in the winter months, with a secondary maximum during the late spring and early summer. High intensity thunderstorms can contribute large proportions of local annual rainfall in late spring and summer. Summer temperatures are warm at lower elevations, but the growing season is relatively short; frost has been recorded in every month in Priveville.

Major rivers and streams in the Lower Crooked include the Crooked River, Ochoco Creek, McKay Creek, Little McKay, Creek, Allen Creek, Lytle Creek, and Mill Creek. Flooding is largely controlled by the Ochoco Dam (built in 1921) and Bowman Dam (built in 1961). The total river mileage for these waterways is approximately 132 miles. In addition the watershed has numerous minor intermittent and perennial streams, small reservoirs, and wetland areas.

The Upper Crooked River and Beaver-South Fork Watershed

These watersheds encompass a similar range of ecological conditions as the Lower Crooked. Land use and management differs from that of the Lower Crooked in that the ownership parcels are much larger (ranches of 20,000 acres or more are common) and public lands make up a larger percentage of the landscape. These watersheds are above the large reservoirs of the Crooked River system, and here there is little storage capacity for irrigation, leaving instream flows and late season availability of irrigation water more dependent upon the conditions of winter snow accumulations and seasonal rainfall.

Elevation ranges from a low point of 3230 ft. at Prineville Reservoir to a high point of 7130 ft. on Snow Mountain, the headwaters of the South Fork Beaver Creek. Communities within the watershed include Post and Paulina. Major rivers and streams in the Upper Crooked include the Horse Heaven Creek, Newsome Creek, Lost Creek, Camp Creek, Beaver Creek, Bear Creek, and the North and South Forks of the Crooked River.


The Crooked River Watershed Council collected multi-parameter water quality data at up to 32 sites within the Crooked River watershed from 2010 through 2014. The types of data collected were physical and biological/chemical, including: continuous water temperature, pH, specific conductance, salinity, dissolved oxygen as mg/L and % saturation, turbidity, nitrates, total phosphates, and total Coliform/E. coli.

Measurement quality objectives follow elements in the DEQ Volunteer Monitoring QAPP ( ), and adhere to the CRWC Sample Analysis Plan developed in collaboration with the Oregon Department of Environmental Quality. Data has been evaluated by ODEQ for meeting standards of quality control.

Continuous temperature monitoring was conducted by deploying thermistors at the multi-parameter sampling locations. Thermistors were deployed in the spring and removed from monitoring locations in late fall when water temperatures are no longer at risk of exceeding state criteria. All physical and biological/chemical parameters were collected at least once monthly from May through October.

Site selection consideration for analysis included adjacent ecological conditions and management practices, impoundments, channel morphology, and stream inputs. Sample points bracket areas delineated by these conditions, allowing trend and impact of the target reach to be observed. The aggregation of extensive sample point and reach trend information collected in the watershed is used to develop a basin scale understanding of water quality conditions.



Water temperatures are critical to fish growth and survival at all life stages. Excessively warm stream temperatures increase stress and disease, raise metabolism, lower growth rates, and enhance conditions for introduced non-native predators. Temperature affects the dissolved oxygen potential in water – the warmer the water, the less dissolved oxygen it can hold. Fish cope with thermal stress and the related water quality impairments by adjusting their behavior. Coldwater fish may seek refuge during the heat of the day in nearby cooler waters that are fed by springs or groundwater, while others may migrate great distances to seek out cooler refuge.

Stream temperatures are influenced primarily by direct solar radiation, air temperature, and movement of groundwater into streams (Moore and Miner, 1997). Basic approaches to minimizing increases in water temperature include: providing shade, maintaining a narrow stream, and maintaining adequate in-stream flows. Water temperature is closely correlated to water quantity, such that more thermal energy is required to increase water temperature under greater flows. Vegetation also affects most of these factors and land use and management often have a direct influence on vegetation.

Oregon’s temperature standard (OAR 340-041-0028) is designed to protect the different life stages of fish and aquatic life, and has several different numeric temperature requirements (criteria) based on the type of aquatic life history and species being supported. These numeric criteria are based on a seven-day moving average of daily maximum temperatures.

ODEQ’s salmonid spawning criterion of 15°C is only applied in streams that are identified as supporting salmon and steelhead spawning; no streams in the Crooked River watershed currently meet this criterion. Therefore, streams in the Crooked River watershed were only evaluated against the salmonid migration and rearing criterion of 18°C. If the reintroduction of anadromous fish into the assessment area is successful, it is possible that the spawning criterion will then be applied.

Temperatures and variability reported here are in reference to the seven-day average maximum temperature, unless otherwise noted.

Dissolved Oxygen

Adequate concentrations of dissolved oxygen (D.O.) are essential for supporting fish, invertebrates, and other aquatic life. Some aquatic species, including salmonids, are sensitive to reduced concentrations of D.O., especially during early life stages as eggs and alevins. Dissolved oxygen concentrations in the water column vary naturally over the course of the day due to temperature changes and photosynthetic processes; D.O. levels in the water are typically at their lowest during the early morning hours when photosynthesis is typically lowest.

Concentration of dissolved oxygen within water also undergoes seasonal fluctuations. Warmer water temperatures increase the amount of plant production and thereby increase dissolved oxygen. However, the decomposition of plants material requires oxygen and leads to decreases in dissolved oxygen. Changes in flow patterns that affect the aeration of the water; sewage seepage, urban runoff, and nutrient deposition all increase the amount of organic and inorganic compounds within the water and can lead to reduced oxygen levels as nutrients and organic matter undergo chemical oxidation.

Dissolved oxygen can be measured either as mg/L of oxygen or as percent of saturation. Percent of saturation is the amount of oxygen that can be held within the water at that specific temperature and altitude. Cold water holds more dissolved oxygen than warm water, and water at higher altitudes holds less dissolved oxygen than water at lower altitudes.

The water quality standard (OAR 340-041-0016) for dissolved oxygen takes into account the salmonid life stage present, barometric pressure, altitude and temperature. Dissolved oxygen levels are most stringent during the spawning season. In the Deschutes basins, redband/steelhead trout typically spawn during the spring months from March to May (Zimmerman, 1999). At other times of the year the “cool-water” or “cold-water” criteria apply. For the assessment area, the standard can generally be summarized as follows: (1) during the spawning season (January 1-May 15), the D.O. may not be less than 11.0 mg/L, or if conditions of barometric pressure, altitude and temperature preclude attainment of 11.0 mg/L, then D.O. levels must not be less than 95 percent of saturation for water bodies identified as providing cold-water aquatic life, the D.O. must not be less than 8.0 mg/L or 90 percent of saturation; and (3) for water bodies identified as providing cool-water aquatic life, the D.O. may not be less than 6.5 mg/L. The designation of “cool-water” and “cold-water” is determined based on the ecological zone in which the water body is found. Because the CRWC measures DO with grab samples periodically, it is not possible to use the 30-day mean minimum. Considering the tributaries in the watershed as “cold-water”, any site recording under 6 mg/L is a concern.


This is a measure of the hydrogen ion concentration (pH) of the water using a logarithmic scale of 0.0 to 14.0. Any pH below 7.0 is acidic while a pH greater than 7.0 is alkaline. Spawning and rearing of salmonid fish species are the most sensitive beneficial uses affected by pH. Values of pH outside the range in which a species evolved may result in both direct and indirect toxic effects. Elevated pH levels can cause dramatic increases in toxicity of other pollutants, such as metals and ammonia, and cause can lead to fish kills.

Like temperature, pH naturally varies both daily and seasonally. Fluctuations in pH are usually the result of the photosynthetic activity of aquatic plants or algae. Algae and aquatic plants become food for aquatic insects and crustaceans, and are an important part of the stream ecosystem. However, over-stimulated plant growth from warm water and high levels of nutrients can cause an increase in pH, a decrease in the available oxygen, and alter aquatic invertebrate and plant communities. Nutrient sources in streams often include septic systems, treated waste water from municipalities, animal feed lots, and fertilizers used in agriculture. These conditions can be exacerbated by low stream flows and lack of riparian cover.

The levels of pH in streams are typically highest late in the afternoon when photosynthesis is at its maximum. The pH standard for streams in the Deschutes Basin (including the Crooked River watershed) states that pH values should not fall outside the range of 6.5-8.5 (OAR 340-041-0135). However, the Crooked River drains the Ochoco Mountains, which are more similar geologically to eastern Oregon than the Cascades. Eastern Oregon has a maximum pH criterion of 9.0, and as part of the TMDL analysis, ODEQ may raise the maximum pH criterion for the Crooked River watershed from 8.5 to 9.0, to reflect the local geology, or background conditions.


Bacteria in the Crooked River Watershed are indicated by measuring fecal coliforms, which are one kind of bacteria found in animal and human feces. High levels of bacteria can cause human illnesses. Thus the most sensitive beneficial use protected by the bacteria standard is water contact recreation. Recreation includes activities such as swimming or fishing where people could swallow or have water touch open cuts or sores. The bacteria standard also does not allow bacteria in numbers high enough to interfere with waters used for domestic purposes, livestock watering, irrigation, or other beneficial uses.

The standard for bacteria requires measurement in the form of “most probable number” (MPN), or the number of coliforms per 100 milliliters (ml) of water. The MPN is the number which makes the observed outcome most probable (Blodgett, R., 2010). There is an equation to calculate MPN or one can use an 95% confidence interval table such as is used at the CRWC.

The ODEQ standards state that the MPN in the Crooked River Watershed should not exceed a mean of 126 E. coli organisms per 100 ml over a 30-day period, and should not at any one point exceed 406 E. coli organisms per 100 ml. Again, since the grab samples do not allow the calculation of 30-day averages, locations of concern are those above the maximum standard of 406 E. coli organisms per 100ml.


Nitrates and phosphorus are assimilated by plants and are necessary for growth, but often there is excess of either one or both that leaches through the soil or reacts with other substances. Nitrates and phosphorus are found in fertilizers and can get into water via runoff from cropland and leakage through the soil. Nitrates can also get into water from runoff of animal waste or industrial discharges. Both nitrates and phosphorus provide food for plankton and are necessary for underwater plants, both of which may be food sources for fish. If too abundant in water, they may cause the biological oxygen demand (BOD) to increase because they are not processed quickly enough, the water becomes cloudy, and the sun cannot reach through to plants to photosynthesize. This process often occurs in older lakes and is also referred to as eutrophication. Eutrophic lakes and rivers have high nutrient inputs, high plant production, murky water, anoxia, toxicity, and reduced ecosystem services (Carpenter, S.R., Ludwig, D., and Brock, W.A., 1999). Since rivers have a surface flow and higher rates of aeration, eutrophication does not happen as frequently. However, high nutrient levels can still cause too much growth, leading to high rates of respiration and decomposition which increase the amount of carbon dioxide in the water. Aside from a decrease in oxygen and possible anoxia, this can potentially decrease the pH as compounds react with carbon dioxide to form acids.

In the Crooked River Watershed, phosphates are measured as total phosphorus in the water, and the concentration of nitrites and nitrates are added together (both in units of mg/L). Because a total maximum daily load (TMDL) has not been established for the Deschutes Basin by the DEQ, there no set standard for nutrient loads. The EPA has recommended national limits for phosphorus and nitrogen, the concentrations of which differ based on whether or not the water flows into a lake or reservoir because they are more at risk for eutrophication. A “healthy” system flowing into a reservoir should not exceed phosphorus concentrations of 0.025 mg/L, and systems not entering a reservoir have a limit of 0.1 mg/L (Bartenhagen, K.A., Turner, M.H., and Osmond, D.L, n.d.).


Turbidity is related to total suspended solids (TSS), which can include attached toxins carried in the water column. Once in the water column, some compounds can enter directly into the aquatic food chain through fish and other high trophic-level species. Other toxins make their way into the food chain by adhering to fine sediments, which deposit onto the aquatic substrate and are incorporated into benthic organisms (UDWC, 2006).

Sediment loading occurs from natural and anthropogenic influences and can contribute to the turbidity of an aquatic system. The local geology, soils, slope, health of the riparian zone, precipitation rates, and natural stream flows all can contribute to natural rates of sediment loading and turbidity. Land management practices, storm water discharges, construction, logging, roads, flow regulations, and agricultural activities can increase the sediment load and turbidity above natural levels (UDWC, 2006). Unstable and avulsing stream banks also contribute substantial loads of fine sediment into the water column causing increased turbidity. The Oregon Watershed Assessment manual recommends an “evaluation criteria of 50 NTU” as the level at which salmonid eyesight is negatively affected for purposes of feeding and escapement (Watershed Professionals Network, 1999).


Conductivity measures the ability of water to conduct electricity based on anions (elements with a negative charge) and cations (elements with a positive charge) in the water. This is mostly dependent on the type of soil and rock through which water infiltrates and percolates. For example, in the Crooked River Watershed, the water originating in the South Fork/ Beaver Creek sub-basin flows through primarily alkaline rock, which is composed of alkali metals that are conductive compared to other chemical elements (ChemEd DL, n.d.). Thus, in general, one might expect the conductivity to be higher in that sub-basin and lesser in the Lower Crooked River sub-basin. Conductivity can also be influenced by other factors such as nearby industrial outputs.

Conductivity is usually measured in microsiemens per centimeter (uS/cm). According to the EPA, rivers in the United States range in conductivity from about 50 to 1500 uS/cm, and freshwater systems supporting fisheries should range from about 150 to 500 uS/cm (USEPA, 2012). Once a baseline is established for conductivity in a reach, it can be a good indicator of water quality in that if it changes vastly in a short period, there may be a new source of contamination.


Use the Water Qualitmenitems to view the complete dataset and the sample locations, create charts, or export data.


Bartenhagen, K.A., Turner, M.H., & Osmond, D.L. (n.d.) Phosphorus. Retrieved from

Borok, A. (n.d.) Water quality standard for turbidity; changes to aquatic life criteria [PowerPoint slides]. Retrieved from

Blodgett, R. (2010). Bacterial analytical manual appendix 2; most probable number from serial dilutions. Retrieved from

California Regional Water Quality Control Board. (2005). The effects of temperature on steelhead trout, Coho salmon, and Chinook salmon biology and function by life stage; implications for Klamath basin TMDLs. California. Author: Carter, K.

Carpenter, S.R., Ludwig, D., & Brock, W.A. (1999). Management of eutrophication for lakes subject to potentially irreversible change. Ecological Applications, 9, 751-771.

ChemEd DL. (n.d.). GenChem textbook. Retrieved from

Lenntech. (2013). Part II of “matter cycles”; the nitrogen cycle. Retrieved from

Oregon Department of Environmental Quality (ODEQ). (2012). Water quality standards: Beneficial uses, policies, and criteria for Oregon division 41. Retrieved from

Oregon Department of Environmental Quality (ODEQ). (n.d.) Oregon water quality index report for Deschutes and Hood basins; water years 1986-1995. Retrieved from use this for a little past reference on eutroph in crooked river/ efforts to improve it

RiverWatch Institute of Alberta. (2010). Interpreting phosphorus test results. Retrieved from

Sigler, J.W., Bjornn, T.C., & Everest, F.H. (1984). Effects of chronic turbidity on density and growth of steelheads and coho Salmon. Transactions of the American Fisheries Society, 113, 142-150.

Teton Science Schools. (n.d.) Nitrogen and phosphorus. Retrieved from

United States Environmental Protection Agency (USEPA). (2000). Ambient water quality criteria recommendations; information supporting the development of state and tribal nutrient criteria. Washington, DC.

United States Environmental Protection Agency (USEPA). (2012). Water: Monitoring and assessment. Retrieved from

Crooked River Watershed Council, 498 SE Lynn Blvd, Prineville, OR 97754, 541-447-8567

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