A Multi-Year Longitudinal Study of Water Quality Parameters in Four Salmon-Bearing and Recreational Streams on Mount Hood, Oregon

Four streams–Clear Fork, Lost Creek, Camp Creek and Still Creek–in northwestern Oregon’s Sandy River Basin were monitored for temperature, dissolved oxygen levels, and fecal bacterial concentrations in a multi-year analysis examining stream health for recreational users and anchor habitat for Pacific Salmon. Temperatures were recorded using micro –T temperature loggers at 15 locations, during 22 July - 5 September 2006, 2 July - 4 September 2007, 20 June - 7 September 2008, 23 June - 9 September 2009, and 2 July –9 September 2010. The Seven-Day Average Maximum water temperature (7-DAM) of 13°C was used as a reference value for the biological limit governing suitable salmonid spawning and egg incubation conditions. The maximum 7-DAM temperatures occurred on different dates and all streams neared or exceeded the 13°C standard at least once each summer. Dissolved oxygen levels were measured at weekly or longer intervals in 2006, 2007, 2008, and 2009. Dissolved oxygen levels fell below the 9.0 ppm standard for Clear Fork on almost half the sampling dates in 2006, 2007, and 2009. Concentrations of the bacterial genus Enterococcus were measured as an indicator of fecal contamination. Samples were collected at 15 sites along the four streams. Weekly samples were collected during a 9 week period from July - September 2007, an 11 week period from June - September 2008, and an 11 week period from June - September 2009. Enterococcus counts exceeded the federal recommended national criterion value of 61 colony forming units (CFU) per 100 mL every year in Camp Creek and occasionally elsewhere, with exceedances trending towards late summer.


Introduction
This four-year study examined characteristics of four streams on the western slopes of Mount Hood, Oregon, that are both salmonbearing and recreational. The presence of campgrounds, cabins, a wastewater treatment plant, and spawning salmonids listed as threatened under the Endangered Species Act provides a complex and interesting milieu for interactions. Our measurements were of water quality parameters that impact both salmonid health and the health of campers in the Mount Hood National Forest who use the streams for recreational purposes.
Endangered Species Act listings have increased attention and funding for restoring degraded watersheds for threatened Pacific salmon Oncorhynchus spp. and steelhead Oncorhynchus mykiss [1]. However, wild salmon stocks have continued to decline since the mid-1800s [2]. The Sandy River Basin Working Group [3] confirmed that habitat degradation is the most important stressor on salmonid habitat within the Sandy River basin. The Sandy River basin supports spawning habitat for wild populations of spring and fall Chinook (Oncorhynchus tshawytscha), Coho (Oncorhynchus kisutch), and winter Steelhead (Oncorhynchus mykiss), all listed as threatened under the U.S. Endangered Species Act in the lower Columbia River [4]. The Oregon Department of Fish and Wildlife has implemented a Native Fish Conservation Policy [5].
This study focused on examining salmonid habitat by measuring three known indicators of habitat quality: water temperature, dissolved oxygen, and bacterial concentration. Human activities (e.g. riparian deforestation, and waste treatment plants) often alter water quality attributes. Salmonids coping with a stressor in one category such as thermal stress are less capable of adapting to additional stressors [6].
Brannon et al. [7] indicated that the poikilothermic nature of salmonids requires particular attention in determining how to maintain or restore appropriate thermal regimes. Temperature directly influences metabolic rate, growth, and additional physiological factors [8]. Poole et al. [9,10] emphasized water temperature as a determinant in overall water quality of individual streams and entire watersheds. Streams such as those in the Sandy River basin, buffered by groundwater sources, transfer cool water in summer from aquifers to streams [11].
Negative consequences associated with elevated temperatures result in increased stress levels, inability to cope with additional stressors, disease, bioenergetic depletion, or lethality [12]. Thermal refugia, such as holes scoured out under logs during high flows, can shelter salmonids from thermally stressful conditions [12,13]. The EPA [14] has provided upper optimal temperature threshold criteria for specific salmonid life cycles using a 7-day average maximum (7-DAM) of the daily temperature value. Excessive water temperatures pose a risk for salmonid spawning, rearing, migration, and smoltification depending on thermal stressor magnitude, duration, and frequency [12,15]. High temperatures have been known to increase the virulence of pathogenic diseases in fish, increase metabolic rate, and decrease the water's dissolved oxygen concentration [16]. Kocan et al. [17] found that disease rate increased with a progressive rise in temperature, producing negative consequences for migration stamina and evasion of predators during early life stages.
As another focus of this study, the presence of the bacterial genus Enterococcus is an indicator of fecal contamination which threatens human health and can contain many toxic materials that can bioaccumulate in salmonids. Enterococci are part of the normal intestinal microbiota of humans and many animals, and include species that are significant pathogens. Their presence in freshwater habitats indicates fecal contamination from a human or animal source [18]. They can be monitored relatively easily because cultivation on selective media at 41uC favors the growth of enterococci over that of other bacteria [19]. From human data, there is a direct correlation between the concentration of enterococci in recreational waters and swimming-associated gastroenteritis [20]. The EPA recommended recreational water quality standards for human health for Enterococcus in recreational freshwater were employed in this study [21].
While enterococcal diseases are not common in fish, salmonids are susceptible to infection by enterococci and other closely related bacteria under certain circumstances [22]. The presence of bacterial contamination impacts the stress load in stream systems and compromises resistance to disease [6]. One typical salmonid infection stems from the fungus Saprolegnia parasitica especially affecting spawning adults and juveniles under multiple stresses [23].
Dissolved oxygen concentrations are inversely related to water temperature, but they can increase due to aeration that occurs when water spalshes over rocks. For water in which salmonids spawn and incubate, the State of Oregon requires a minimum dissolved oxygen concentration in the water column of 9.0 ppm [24]. This is similar to the lower limits on dissolved oxygen set by the State of Washington, the Province of British Columbia, and most Northwestern Indian Tribes [25]. Lower dissolved oxygen levels can significantly impair salmonid reproduction and survival [26].
Monitoring the variables described above over the course of a multi-year study allowed us to document the variability in space and time of characteristics important to stream health for both fish and for people using the streams recreationally. We selected these variables over other environmental factors that impact streams because they had accompanying Federal standards and relative ease of quantification. Other variables, like shading and precipitation, lack Federal standards and are more difficult to quantify. For shading, its constantly changing nature at any location both across the course of a day and also across the summer pose a great challenge. Precipitation has very localized patterns on at different sites on Mount Hood that make quantification difficult (see for example Rhododendron and Government Camp precipitation data sets, accessible online through the National Climate Data Center).

Ethics Statement
We thank the personnel of the U.S. Forest Service's Mount Hood National Forest for permission to conduct this research. The streams in this study, Clear Fork, Lost Creek, Camp Creek, and Still Creek, are tributaries to the Sandy River, now a freeflowing tributary to the Columbia River. Streams varied in length from 1 km for Clear Fork to 5.3 km for Still Creek, the longest stream. Streams are fed either entirely or predominantly by groundwater sources and flow through forests characterized by Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). Our sampling sites ranged in elevation from 1128.1 m to 482.5 m, see Table 1.

Site Description
Spawning surveys conducted by the Oregon Department of Fish and Wildlife (ODFW) from 1996-1999 and 2002-2005 provide population estimates for the streams included in this study. The ODFW spawning survey records suggested productive salmonid spawning for Clear Fork and Still Creek in 1998 with redd densities of 28.3 redds/1.61 km and 27.9 redds/1.61 km respectively [27]. The ODFW surveys suggested relatively unproductive salmonid spawning in 1998 for Lost Creek and Camp Creek with records of 6.5 redds/1.61 km and 4.5 redds/1.61 km respectively [27]. All four streams maintained these productivity levels over  The removal of the Marmot Dam in 2007, whose fish passage structures posed a challenge to migrating salmonids on the Sandy River, reestablished a free-flowing system. This increased the potential for utilization of historic spawning grounds including the four streams in this study, all of which are tributaries of the Sandy River upstream from the former Marmot Dam site. A comprehensive salmonid survey of Sandy River tributaries has yet to be completed following the removal of the Marmot Dam. Geomorphic and hydrologic data collected by the USGS after dam removal have been collected [29]. We thank the personnel of the U.S. Forest Service's Mount Hood National Forest for permission to conduct this research. We thank them as well for access to normally inaccessible locations, and for occasional help with transportation.

Temperature
The temperature sensors used for recording water temperatures were micro-T model DS1921G temperature loggers which employ iButton technology. These have +/21uC accuracy, 0.5uC resolution, a range of -40uC to +85uC, and can record a maximum of 2,048 temperature measurements (a total of 85 days at one reading per hour). All micro-T loggers were calibrated before deployment using a laboratory-quality alcohol thermometer. In preparation for deployment, the micro-T temperature loggers were programmed to record measurements in degrees Celsius every hour on the hour. They were deployed in late July of 2006, early July of 2007, late June in 2008 and 2009, and early July of 2010. These dates were determined by water depth, and therefore site access, in the four streams. Micro-T loggers were retrieved in early September. Upon retrieval, the 7-DAM was calculated. By definition, a 7-DAM is the average of the maximum water temperature for seven consecutive days. The maximum 7-DAM for each site was graphed over the entire sampling period and compared to the 13uC 7-DAM upper optimal standard for spawning and egg incubation [12,14].
In a typical deployment, two micro-T loggers were used at each site for redundancy. The ParafilmH M-wrapped micro-T loggers were encased in a perforated plastic golf ball sealed with a zip tie. This insured that the two loggers would remain together and be fully exposed to the current. The micro-T loggers were attached to cord-wrapped rocks coated with a layer of rubber on the bottom to prevent slipping of the cord. These rocks were then hidden in each stream in deep areas with swift water flow.

Bacteriological Analysis
Weekly water samples were collected from 15 locations along the four streams. The samples were collected aseptically in sterile 120-mL polypropylene specimen containers. Randomized duplicate samples were obtained each week to confirm accurate counts. Each site was duplicated at least once during each season of the study. Field blanks of sterile water were also prepared at randomized sampling locations and lab blanks were prepared upon return to the laboratory to confirm that contamination did not occur during sample collection and analysis. All field samples and blanks were kept on ice in insulated coolers during transport to the laboratory. The samples were analyzed within 6 hours after collection of the first sample. Each water sample was vacuum filtered in aliquots of 100 mL through a 47-mm diameter Tritonfree cellulose nitrate membrane filter with a pore size of 0.45 mm. To enumerate enterococci, the membrane filters were aseptically transferred to mE agar (Difco) and incubated for 48 hours at 41uC [19].
After incubation, the filters were transferred to esculin iron agar (EIA, Difco) and incubated for an additional 30 minutes at 41uC [19]. Bacterial colonies that produced red colonies on mE agar were identified as ''suspected enterococcus'' and those that also formed a black to reddish-brown precipitate when transferred to EIA were identified and counted as ''confirmed enterococci.'' The standard of a single sample maximal allowable density of 61 colony forming units (CFU)/100 mL for waters in which full body contact recreation takes place was used as the threshhold for excessive concentrations of enterococci. This standard is recommended for state and tribal waters of freshwater orgin to protect primary contact for safe recreation [21]. Young campers were frequently seen playing in the water of Lost Creek, Still Creek and Camp Creek.
Error was minimized with three independent counts of the colonies on each membrane filter, and high colony counts that were readable but nonetheless challenging by eye were confirmed by microscopic observation. Even with a microscope, colony counts above 300 colonies per plate could not be reliably made, and these values are represented in our data graphically simply at the 300 colony level and discussed in the text as exceeding the federally recommended water quality criterion for full body contact recreation of 61 CFU.

Cross-sectional Stream Analysis Protocol for Dissolved Oxygen
For each stream analyzed, a cross-sectional template was employed. This template was made by stretching a rope across the stream and setting a series of eight equidistant points starting at the left bank and ending at the right bank. The template gave an objective and repeatable way to measure dissolved O 2 since water levels and channel widths generally changed every week.

Dissolved O 2
The dissolved O 2 meter used was a portable HACH HQ20. It has an O 2 probe with an accuracy of +/20.1 mg/L for concentrations between 0-8 mg/L and +/20.2 mg/L for concentrations between 8-20 mg/L. The O 2 probe was calibrated weekly prior to taking in-stream measurements. Measurements of O 2 were made at the eight established equidistant points according to the cross-sectional stream analysis method. After the O 2 levels were measured, a stream average was calculated for each week. All O 2 measurements were made in the water column rather than making intragravel measurements which are highly correlated with water column measurements but more disruptive to the stream environment.

Temperature
The 7-DAM values are graphed with the 13uC upper optimal threshold for salmonid spawning and egg incubation indicated by a red dashed line. Each 7-DAM value was associated with a particular stream measurement location. The sampling locations are encoded by the line color, indicated in the key by name and number (e.g. Lost Creek 7 DAM (A) is the most upstream site on Lost Creek) and indicated on the map provided as Figure 1. The streams are all graphed with early summer data to the left proceeding to later in the season as the axes go to the right. Temperature peaked at different times in different years, in a more unpredictable fashion than an assumption of streams growing warmer as the summer progressed would suggest.
All temperature logger sites in Clear Fork were in close proximity to each other. Each maximum 7-DAM value exceeded the 13uC upper optimal threshold for salmonid spawning and egg incubation during one distinctive warming period each summer:

Bacteria
The figures below display Enterococcus counts over the course of three sample years. In general Camp Creek was the most heavily contaminated of the four streams. However there was no stream in which the level of bacterial contamination was uniformly acceptable.
Clear Fork water samples all remained below the 61 CFU value for confirmed Enterococcus counts, the federally recommended water quality criterion for full body contact recreation, for all water samples in 2007 and 2008, but in 2009 exceeded that value in week 10 at sampling sites B and C, see Figure 6.
Lost Creek water samples all remained below the 61 CFU value for confirmed Enterococcus counts, the federally recommended water quality criterion for full body contact recreation, for all

Temperature Analysis
Thermal regimes of rivers are vitally important to the overall health of aquatic ecosystems, water quality, and the distribution of aquatic species [30]. For salmonids, thermal regimes are an especially critical environmental factor, with different life stages impacted at different temperature levels [8,9,10,12,16]. Spawning and incubation of eggs in the gravel is an especially sensitive life history stage. An upper optimal temperature of 13uC marks the biological limit governing suitable salmonid spawning and egg incubation conditions [12]. Peak summer temperatures that near or exceed 13uC would inhibit the abilities of salmonids to maintain a breeding population in a stream. Given the presence in the Sandy River basin of Coho salmon, fall-run Chinook salmon, spring-run Chinook salmon, Chum salmon, and Winter-run steelhead, spawning and subsequent incubation take place throughout much of the year [31]. In the Sandy River basin, winter-run steelhead may emerge from the gravel as late as the end of August, and fall-run Chinook may emerge as late as the beginning of July, so that incubating eggs are potentially present in streambed gravels throughout our study periods [31].
Clear Fork experienced high thermal stress for a historically productive anchor habitat [27,28]. Each site on Clear Fork exceeded the 13uC biological limit at least once during the sampling period for the 7-DAM. This was not true for any other stream. Each site on Clear Fork recorded the Camp Creek, a relatively unproductive stream (27,28), reported pronounced temperature variability between upstream and downstream sites. The most favorable temperatures, located at the farthest upstream site, would have been inaccessible to salmonids due to a large waterfall about 30 meters downstream of temperature logger site IL. This upstream site never approached the 13uC biological limit. Midstream and downstream temperature loggers approached or exceeded the 13uC biological limit.
Still Creek, in the summer of 2009, had the greatest temperature separation from upstream to downstream sites respectively compared to the other streams. Despite the success of salmonids in Still Creek [27,28], the farthest downstream site in the summer of 2009 was of most concern out of all the temperatures recorded. This was the only site that exceeded the 13uC biological threshold on two separate occasions in one summer, the longest for 22 consecutive days. In 2010, the farthest downstream site exceeded the standard for 31 consecutive days.

Dissolved Oxygen Analysis
The South Fork of Lost Creek experienced low dissolved oxygen levels at intervals, but this is a small tributary whose depth and flow rates would limit its usefulness to spawning salmon. The unexpected finding was that Clear Fork experienced frequent low dissolved oxygen levels for what was a historically productive anchor habitat (27,28). Aside from the very shallow South Fork of Lost Creek, the other streams did not experience low dissolved oxygen levels.

Bacteriological Analysis
Bacterial contamination varied between streams and within individual streams each summer (2007)(2008)(2009)). Concentrations of enterococci generally increased from early to late summer and the federal single sample Enterococcus recommended national criterion value of 61 CFU/100 mL for recreational waters was exceeded at various times each year.
Camp Creek was the most frequent tributary in this investigation to exceed the federal standard in the summer months with numerous spike events in excess of 61 CFU/100 mL above the single-sample limit (see Figure 8). Clear Fork's bacterial spike events in excess of 61 CFU/100 mL above the single-sample limit occurred at two sites during the final two 5-week sampling periods in 2009. Lost Creek experienced a single spike event in excess of 61 CFU/100 mL, in week 10 of 2009. Bacteriological water   Creek's high frequency of spike events in excess of 61 CFU/100 mL above the single-sample limit was due in part to a specific set of circumstances brought to light by our sampling. In 2008, a change in management at the Government Camp sewage treatment plant contributed to an improperly assembled discharge pipe. Direct discharge of raw sewage into Camp Creek ensued. At site I, the site about 15 meters downstream of the sewage discharge pipe, four of the sampling periods exceeded 300 CFU/100 mL and were deemed too high for accurate counting. Comparable levels of contamination were not detected at site IU, located about 15 meters upstream of upstream of the discharge pipe. The Government Camp sewage treatment plant was the only such facility in our sampling area, and contamination due to sewage runoff had previously been listed as a concern in the Sandy River basin [31].
Earlier studies have reported increased levels of fecal bacteria in campground streams associated with recreational activity [32,33,34]. Increases may have been due to stirred up sediment or waste from dogs and horses rather than to human waste [32,33]. Along with the formal campgrounds equipped with pit toilets in the Mount Hood National Forest, like those on Camp Creek, Still Creek, and Lost Creek, informal or dispersed campsites are scattered along the streams and these lack sanitary facilities. Use of campsites lacking sanitary facilities has been shown to increase bacterial contamination of nearby streams, especially following weekends of heavy camping activity [34]. The

Conclusions
The Sandy River basin and its small tributary streams have been identified as very important to efforts to restore Chinook, Coho, and Steelhead [31]. This is considerably more important now than when the Sandy River Basin Characterization Report came out in 2005 [31], because the dams on the Sandy River have been removed and more habitat is easily accessible to returning spawners than had been for decades [29]. Elevated enterococci present in Camp Creek and Lost Creek is a transient but probably unavoidable problem [32,33,34]. Elevated water temperatures above the 7-DAM maximum temperatures were common but occurred at different times during different years. Clear Fork alone experienced frequent low dissolved oxygen levels. The environmental measurements reported in this article highlight the potential for restoration of wild salmonids in the Sandy River basin with even modest habitat recovery efforts. However, the ongoing Federal lawsuit brought by the Native Fish Society highlights the peril to wild fish posed by the unprecedented number of hatchery fish now able to reach spawning areas that  were formerly inaccessible to them, due to the current regime of hatchery operations [35,36,37,38,39,40], and the future of the four steams studied remains in doubt.