Deschutes River and Tumalo Creek 2005-2008 (Bend, Oregon)

Upper Deschutes Watershed Council Technical Report

City of Bend Ambient Water Quality Monitoring: Deschutes River and Tumalo Creek 2005‐2008 (Bend, Oregon)

Prepared for: City of Bend Public Works Department 575 NE 15th Street Bend, OR 97701

Prepared by: Lesley Jones and Ryan Houston Upper Deschutes Watershed Council PO Box 1812 Bend, OR 97709

June 30, 2010

Acknowledgements

There are numerous individuals and organizations that have helped support the water quality monitoring that is part of this report.

The City of Bend staff, including the team at Public Works, the Laboratory and Water Divisions, were instrumental in project planning, implementation, and final documentation. In particular, the following team members have dedicated a tremendous amount of time and energy to the monitoring work presented in this report: Steve Prazak, Jeff Buystedt, Drexell Barnes, Ollie Fick, Patrick Griffiths, Wendy Edde and Tom Hickmann.

The Oregon Department of Environmental Quality Laboratory and field crews contributed a great deal of guidance with methodologies and assistance in the development and adaptation of field protocols. In particular, the following contributors are appreciated: Steve Hanson, Greg Pettit, and Michael Tichenor.

Bonnie Lamb, Oregon Department of Environmental Quality Natural Resource Specialist Eastern Region and Joanne Richter of Richter Environmental Consulting, assisted with the early development of the monitoring program in the City of Bend.

The UDWC Water Quality Monitoring Program relies on funding from the City of Bend, Oregon Department of Environmental Quality 319 Grant Program and the Oregon Watershed Enhancement Board to make the monitoring in this report possible.

The UDWC Water Quality Monitoring Program is guided by the Upper Deschutes Water Quality Committee who provide invaluable guidance and input: Michelle McSwain (Bureau of Land Management), Wendy Edde (City of Bend), Brett Golden (Deschutes River Conservancy), Bonnie Lamb (Oregon Department of Environmental Quality), Ted Wise (Oregon Department of Fish and Wildlife), Kyle Gorman (Oregon Water Resources Department), Lori Campbell (Portland General Electric), Ryan Houston, (Upper Deschutes Watershed Council), Marc Wilcox (U.S. Forest Service, Deschutes and Ochoco National Forests).

City of Bend Ambient Water Quality Monitoring Report ii Abbreviations and Acronyms

Organizations

BLM Bureau of Land Management COID Central Oregon Irrigation District DRC Deschutes River Conservancy EPA Environmental Protection Agency ODEQ Oregon Department of Environmental Quality ODFW Oregon Department of Fish and Wildlife OWEB Oregon Watershed Enhancement Board OWRD Oregon Water Resources Department PGE Portland General Electric TID Tumalo Irrigation District UDWC Upper Deschutes Watershed Council USFS United States Forest Service USGS United States Geological Survey

Technical Terminology

7DMAX Seven day moving average maximum BMP Best management practice °C Degree Celsius cfs Cubic feet per second DMA Designated management agency DO Dissolved oxygen °F Degree Fahrenheit FWS Fall, winter, and spring mg/L Milligrams per liter Ln Natural logarithm NIST National Institute of Standards and Technology NTU Nepthleometric turbidity units OAR Oregon Administrative Rules QA/QC Quality assurance / quality control S Summer TKN Total Kjeldahl nitrogen TMDL Total Maximum Daily Load QD Mean daily flow UGB Urban growth boundary μg/L Micrograms per liter

City of Bend Ambient Water Quality Monitoring Report iii Table of Contents

Executive Summary ...... vii 1.0 Introduction ...... 1 2.0 Study Area ...... 1 2.1 Upper Deschutes River ...... 4 2.2 Tumalo Creek ...... 4 2.3 Existing 303(d) Listings ...... 6 3.0 Monitoring Methods ...... 9 3.1 Quality Assurance and Quality Control ...... 9 3.2 Monitoring Stations and Parameters ...... 12 4.0 Results: 303(d) List Parameters ...... 15 4.1 Temperature ...... 15 4.1.1 Background ...... 15 4.1.2 Upper Deschutes River ...... 16 4.1.3 Tumalo Creek ...... 23 4.2 Upper Deschutes River Dissolved Oxygen ...... 30 4.2.1 Background ...... 30 4.2.2 Status ...... 31 4.3 Upper Deschutes River pH ...... 39 4.3.1 Background ...... 39 4.3.2 Status ...... 39 4.4 Upper Deschutes River Sedimentation and Turbidity ...... 47 4.4.1 Background ...... 47 4.4.2 Evaluation ...... 48 4.5 Summary of Results ...... 53 5.0 Results: Nutrients, Other Compounds and Biological Indicators ...... 55 5.1 Nutrients ...... 55 5.1.1 Nitrogen ...... 55 5.1.2 Phosphorus ...... 57 5.2 Other Compounds ...... 57 5.2.1 Ammonia ...... 57 5.2.2 Chloride ...... 57 5.2.3 Fluoride ...... 59 5.2.4 Sulfate ...... 59 5.3 Biological Indicators ...... 59 5.3.1 Escherichia coli ...... 59

City of Bend Ambient Water Quality Monitoring Report iv 5.3.2 Primary Productivity (Chlorophyll‐a and Pheophytin‐a) ...... 61 6.0 Discussion ...... 62 7.0 Recommendations for Further Study ...... 64 8.0 Bibliography ...... 66

List of Figures

Figure 1. Upper Deschutes River Seven Day Moving Average Maximum Temperature 1997 – 2008 ...... 17 Figure 2. City of Bend Area Seven Day Moving Average Maximum Temperature 1997 – 2008 ...... 18 Figure 3. Upper Deschutes River Hottest Seven Day Moving Average Maximum Temperature by River Mile ...... 19 Figure 4. City of Bend Area Hottest Seven Day Moving Average Maximum Temperature by River Mile ...... 20 Figure 5. Upper Deschutes River Rate of Temperature Change on the Hottest Day ...... 21 Figure 6. City of Bend Area Deschutes River Rate of Temperature Change on the Hottest Day ...... 22 Figure 7. Tumalo Creek Temperature Compared to Salmon and Trout Standards ...... 24 Figure 8. Tumalo Creek Temperature Compared to Bull Trout Standards ...... 25 Figure 9. Tumalo Creek Hottest Seven Day Moving Average Maximum Temperature by River Mile ...... 26 Figure 10. Tumalo Creek Rate of Temperature Change on the Hottest Day ...... 27 Figure 11. Tumalo Creek Hottest Water Day during Bull Trout Spawning and Migration ...... 28 Figure 12. Tumalo Creek Rate of Temperature Change during Bull Trout Spawning and Migration...... 29 Figure 13. Upper Deschutes River Daily Mean Dissolved Oxygen 2001 – 2008 ...... 32 Figure 14. City of Bend Area Upper Deschutes River Daily Mean Dissolved Oxygen 2001 – 2008 ...... 33 Figure 15. Upper Deschutes River Daily Mean Dissolved Oxygen Spawning 2007 – 2008 ...... 34 Figure 16. Upper Deschutes River Daily Mean Dissolved Oxygen Non‐Spawning 2007 – 2008 ...... 36 Figure 17. Upper Deschutes River Grab Dissolved Oxygen Spawning 2007 ‐2008 ...... 37 Figure 18. Upper Deschutes River Grab Dissolved Oxygen Non‐Spawning 2007 – 2008 ...... 38 Figure 19. Upper Deschutes River Daily Maximum pH 2001 – 2008 ...... 40 Figure 20. City of Bend Area Upper Deschutes River Daily Maximum pH 2001 – 2008 ...... 41 Figure 21. Upper Deschutes River Daily Minimum pH 2001 – 2008 ...... 42

City of Bend Ambient Water Quality Monitoring Report v Figure 22. City of Bend Area Upper Deschutes River Daily Minimum pH 2001 – 2008 ...... 43 Figure 23. Upper Deschutes River Daily Maximum pH 2007 – 2008 ...... 44 Figure 24. Upper Deschutes River Daily Minimum pH 2007 – 2008 ...... 45 Figure 25. Upper Deschutes River Grab pH 2007 – 2008 ...... 46 Figure 26. Upper Deschutes River Turbidity Values 2005 ‐ 2008 ...... 50 Figure 27. Probability Plot of Upper Deschutes River Turbidity Values ...... 51 Figure 28. Confidence Interval Plot of Upper Deschutes River Mean Turbidity Values ...... 52

List of Tables

Table 1. 303(d) Listed Impaired Upper Deschutes River Miles and Parameters 2004/2006 .. 7 Table 2. 303(d) Listed Impaired Tumalo Creek River Miles and Parameters 2004/2006 ...... 8 Table 3. ODEQ Reaches and Monitoring Stations on the Upper Deschutes River ...... 13 Table 4. ODEQ Reaches and Corresponding Monitoring Stations on Tumalo Creek ...... 14 Table 5. Upper Deschutes River Dissolved Oxygen Spawning Exceedences 2007 – 2008 .... 35 Table 6. Trend Analysis Hypotheses ...... 49 Table 7. Tumalo Creek Ambient Water Quality Status Summary 2007 / 2008 ...... 53 Table 8. Upper Deschutes River Ambient Water Quality Status Summary 2007 / 2008 ...... 54 Table 9. Upper Deschutes River and Tumalo Creek Nutrients Status Summary ...... 56 Table 10. Upper Deschutes River and Tumalo Creek Other Compounds ...... 58 Table 11. Upper Deschutes River and Tumalo Creek Biological Status Summary ...... 60

List of Maps

Map 1. Upper Deschutes and Little Deschutes Subbasins ...... 2 Map 2. City of Bend Ambient Water Quality Monitoring Study Area ...... 3 Map 3. Dams and Associated Impoundments Located within the City of Bend ...... 5 Map 4. Study Area Water Quality Monitoring Stations ...... 10 Map 5. City of Bend Ambient Water Quality Monitoring Stations within the Study Area .. 11

Appendices

Appendix A: 303(d) listing maps Appendix B: Photos

City of Bend Ambient Water Quality Monitoring Report vi Executive Summary

In 2004, the City of Bend and Upper Deschutes Watershed Council (UDWC) began working together to implement a collaborative water quality monitoring project in the Deschutes River and Tumalo Creek. The five‐year effort included monitoring of 13 water quality parameters at a variety of sites within and adjacent to the City of Bend. The purpose of the monitoring was to develop a baseline understanding of water quality conditions through Bend, evaluate status and trends of water quality parameters on a local and regional basis, and to help inform future studies, management and other activities in the area. Simply stated, the City of Bend initiated this project to more fully understand the quality of the water flowing into the Urban Growth Boundary and, subsequently, the quality of the water after it flowed through the Urban Growth Boundary.

Specific reaches of the Deschutes River and Tumalo Creek have already been included on the 2004/2006 Clean Water Act Section 303(d) list by the Oregon Department of Water Quality because they do not meet state water quality standards for temperature, dissolved oxygen, pH, chlorophyll‐a and/or sedimentation/turbidity. The monitoring in this report has verified some of these listings, provided contradictory information for others, and identified additional reaches of the Deschutes River and Tumalo Creek that may be potential additions to the 303(d) list.

Monitoring results for ammonia, chloride, fluoride and sulfate indicated that values are within established guidelines. Results for nutrients identified values that exceed federal guidance, although the specific source of these nutrients is not known. Biological monitoring identified moderate levels of chlorophyll‐a, suggesting a need for more research. High values of E. coli were recorded at the mouth of Tumalo Creek, although these values are likely to be anomalies.

Recommendations presented in this report include additional monitoring and studies to better understand how key water quality parameters (e.g., dissolved oxygen, pH, temperature, chlorophyll‐a, nutrients, etc.) may be affected by conditions in the Deschutes River (e.g., flow conditions, influence of dams, sedimentation, algal growth, etc.).

City of Bend Ambient Water Quality Monitoring Report vii 1.0 Introduction

In 2004 the City of Bend engaged the services of the Upper Deschutes Watershed Council to assist in the implementation of a water quality monitoring project in the Deschutes River and Tumalo Creek. The five‐year monitoring effort included members of the UDWC and City of Bend staff working together on the monitoring of 13 water quality parameters at a variety of sites within and adjacent to the City of Bend. The purpose of the monitoring was to develop a baseline understanding of water quality conditions through Bend, evaluate status and trends of water quality parameters on a local and regional basis, and to help inform future studies, management and other activities in the area. Simply stated, the City of Bend initiated this project to more fully understand the quality of the water flowing into the Urban Growth Boundary and, subsequently, the quality of the water after it flowed through the Urban Growth Boundary.

This report presents a concise summary of the results of the monitoring from 2004 through 2008. This will provide the City of Bend with information that can be used in its planning and public works activities, and in the development of future monitoring efforts. Where possible, the monitoring results presented in this report are compared to state and/or federal guidelines or standards to provide context.

2.0 Study Area

The City of Bend is located within the Upper Deschutes Subbasin and downstream of the Little Deschutes Subbasin (Map 1). The Deschutes River flows through the center of the City of Bend. Within the Upper Deschutes River Subbasin, the river can be divided into three reaches including the High Lakes (upstream of Wickiup Reservoir), Upper Deschutes (Wickiup Reservoir to North Canal Dam including the City of Bend), and Middle Deschutes (North Canal Dam to Lake Billy Chinook) (Map 1).

The study area for this report includes the High Lakes, Upper, and Middle reaches of the Deschutes River and Tumalo Creek Watersheds because these are the watersheds that surround the City of Bend (Map 2). The study area includes the areas beyond the City of Bend’s UGB because this context allows for a more comprehensive understanding of water quality within the City of Bend. This is particularly important for the City of Bend because there are a number of water quality drivers, such as irrigation diversions and reservoirs, located outside the City that may influence water quality within the City.

City of Bend Ambient Water Quality Monitoring Report 1 Map 1. Upper Deschutes and Little Deschutes Subbasins

City of Bend Ambient Water Quality Monitoring Report 2 Map 2. City of Bend Ambient Water Quality Monitoring Study Area

City of Bend Ambient Water Quality Monitoring Report 3 2.1 Upper Deschutes River

The Upper Deschutes River watersheds cover approximately 893,214 acres and include Charleton Creek, Browns Creek, Fall River, Pilot Butte, McKenzie Canyon Deep Canyon, and Haystack watersheds (USGS, 2008). The Upper Deschutes River headwaters are located on the Deschutes National Forest at Little Lava Lake (river mile 252) where groundwater inflows appear as springs on the north side of the lake. The Upper Deschutes River then flows south from Little Lava Lake to Crane Prairie Reservoir (river mile 243 – 239), and travels east through Wickiup Reservoir (river mile 237 – 227). Downstream from Wickiup Reservoir, three major tributaries contribute flows to the Upper Deschutes River, including Fall River (river mile 205), the Little Deschutes River (river mile 193), and Spring River (river mile 190). Near Spring River, a complex of groundwater springs enters the river.

As the Deschutes River nears the City of Bend, the river flows past the Arnold Irrigation District (AID) diversion before crossing over the southern City of Bend UGB (river mile 172). Four impoundments along the Upper Deschutes River are created by the Colorado Avenue Dam, Pacific Power and Light Company hydroelectric dam (i.e. Mirror Pond), the Steidl and Tweet Dam, and the North Canal Dam (Map 3). Downstream of the diversion located at the North Canal Dam and the northern City of Bend UGB, Tumalo Creek is a major tributary to the Upper Deschutes River. Downstream an additional 30 miles, groundwater springs begin to enter the Upper Deschutes River near Lower Bridge Road (river mile 133). Whychus Creek joins the Upper Deschutes River at river mile 123, and the river flows downstream to Lake Billy Chinook (river mile 120).

The establishment of homesteaders in 1898 and agriculture in the Upper Deschutes River Valley in 1900 marks the start of changes for the Upper Deschutes River (Yake, K., 2003). In 1901, Central Oregon Irrigation District Canal began diverting water from the Upper Deschutes River to support agriculture. Between 1910 and 1922 the four dams through the City of Bend had been constructed for agriculture, timber, and hydroelectricity. Upon the completion of Crane Prairie Reservoir in 1940 and Wickiup Reservoir in 1949 by the U.S. Bureau of Reclamation, the naturally stable year‐round flows of the Upper Deschutes River were significantly modified (USDI, 2006).

2.2 Tumalo Creek

The Tumalo Creek Watershed covers approximately 48 square miles and includes approximately 18 miles of creek. As a perennial stream, Tumalo Creek’s flow is primarily from springs and snowmelt originating in the glaciated eastern Cascades. The highest peaks include Ball Butte 8,091 feet and Tumalo Mountain 7,775 feet. Near the headwaters, perennial

City of Bend Ambient Water Quality Monitoring Report 4 Map 3. Dams and Associated Impoundments Located within the City of Bend

City of Bend Ambient Water Quality Monitoring Report 5

tributaries contribute flow to Tumalo Creek and include South, Middle, and North Forks of Tumalo Creek, Bridge Creek, and Tumalo Lake Creek. The confluence of Tumalo Creek with the Upper Deschutes River is approximately 3,200 feet in elevation. The natural flows in Tumalo Creek fluctuate from low winter time flows of approximately 50 cfs to high spring time flows of approximately 300‐400 cfs.

There are two water diversions in the Tumalo Creek watershed: the City of Bend surface water intake on Bridge Creek and the Tumalo Irrigation Districts’ Tumalo Feed Canal diversion on Tumalo Creek. The City diversion on Bridge Creek is about 500 feet upstream of the confluence with Tumalo Creek at river mile 14.7. The Tumalo Feed Canal diversion is located at river mile 2.5 downstream of Shevlin Park. The City of Bend diversion is operated year‐round whereas the Tumalo Feed Canal is operated from April 15 to October 15 of each year. Flows may drop to less than 5 cfs downstream of the Tumalo Feed Canal during the summer irrigation season (USFS, 1998).

2.3 Existing 303(d) Listings

Under the federal Clean Water Act of 1972, and subsequent amendments, each state compiles a list of rivers, streams, lakes and other waterbodies that do not meet established water quality standards. Every two years, each state submits this list, called a “303(d) list,” to the U.S. Environmental Protection Agency (EPA) for approval. Once a waterbody is on the 303(d) list, the state then develops a Total Maximum Daily Load (TMDL), defining permissible loading of pollutants that may enter the waterbody. Sources of pollutants that are addressed by TMDLs may include point sources such as wastewater discharges, nonpoint sources such as urban and agricultural runoff, natural background sources, and potential future pollution sources. The TMDL is implemented through a Water Quality Management Plan (WQMP) that guides local partners in protecting and managing water quality. The current 303(d) list for the Upper Deschutes and Tumalo Creek is included in Tables 1 and 2.

The state of Oregon is currently in the early stages of developing a TMDL for the Upper Deschutes River and Tumalo Creek, although the completion date is currently unknown (ODEQ, 2004). The TMDL for the Upper Deschutes River will likely include regulation of temperature, dissolved oxygen, pH and chlorophyll‐a.

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Table 1. 303(d) Listed Impaired Upper Deschutes River Miles and Parameters 2004/2006 Sed.& Parameter Temperature Dissolved Oxygen pH Chl‐a Turb. Salmon Bull Trout and Trout Beneficial Spawning Non‐ Multiple Multiple Multiple Multiple Rearing Spawning Use and Spawning Uses Uses Uses Uses and Rearing Migration Fall / Year August 15 – Jan 1 ‐ Spring / Season Year Round Winter/ Summer Summer Round June 15 May 15 Summer Spring ODEQ 8.0 mg/L @ 11.0 mg/L 6.5 ‐ 8.5 >10% NTU Reach River 18 °C 12 °C 6.5 ‐ 8.5 SU 0.015 mg/L 95% Sat @ 90% Sat SU increase Mile Standard not Insufficient Insufficient Insufficient Insufficient Insufficient 223.3 to 303(d) Standards applicable data for data for data for data for data for 244.8 listed met to this evaluation evaluation evaluation evaluation evaluation reach Standard not Insufficient 189.5 to 303(d) 303(d) 303(d) Standard Standard 303(d) applicable data for 220.0 listed listed listed met met listed to this evaluation reach Standard not 168.2 to 303(d) 303(d) 303(d) Standard Standard 303(d) 303(d) applicable 189.4 listed listed listed met met listed listed to this reach Standard not Insufficient 162.6 to 303(d) Standard 303(d) Standard 303(d) Standard applicable data for 168.2 listed met listed met listed met to this evaluation reach Standard not Insufficient 126.4 to 303(d) Standard 303(d) 303(d) 303(d) Standard applicable data for 162.7 listed met listed listed listed met to this evaluation reach (ODEQ, 2004)

Note: The City of Bend UGB extends from approximately river mile 172.00 to 163.25 on the Deschutes River.

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Table 2. 303(d) Listed Impaired Tumalo Creek River Miles and Parameters 2004/2006

Parameter Temperature Dissolved Oxygen pH Chl‐a Sed./Turb.

Salmon and Bull Trout Beneficial Trout Salmon and Salmon and Spawning Multiple Multiple Multiple Multiple Use Rearing Trout Non‐ Trout and Uses Uses Uses Uses Criteria and Spawning Spawning Rearing Migration

Fall / August 15 – January 1 Spring / Season Year Round Year Round Winter/ Summer Summer June 15 ‐ May 15 Summer Spring

ODEQ 8.0 mg/L @ 11.0 mg/L >10% NTU Reach 18 °C 12 °C 6.5 ‐ 8.5 SU 6.5 ‐ 8.5 SU 0.015 mg/L 95% Sat @ 90% Sat increase River Mile

Not Not Not Insufficient Insufficient Insufficient Not Standard 12.5 – 20.0 evaluated evaluated evaluated data for data for data for evaluated met by ODEQ by ODEQ by ODEQ evaluation evaluation evaluation by ODEQ Standard not Insufficient Insufficient Insufficient Insufficient Not 303(d) Standard 0.0 – 12.5 applicable data for data for data for data for evaluated listed met to this evaluation evaluation evaluation evaluation by ODEQ reach (ODEQ, 2004)

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3.0 Monitoring Methods

The monitoring conducted as part of this study was completed by several local, state and federal partners working together at monitoring sites in the Upper Deschutes River and Tumalo Creek watersheds (Map 3 and 4). City of Bend staff monitored twelve locations on the Upper Deschutes River and six locations on Tumalo Creek while the UDWC staff monitored two stations downstream and two stations upstream of the City of Bend. Oregon Department of Environmental Quality monitored an additional five stations on the Upper Deschutes River and the U.S. Forest Service monitored three stations on the Upper Deschutes River in the high lakes area.

The monitoring conducted specifically for this study occurred between 2004 and 2008. However, when additional data from prior to 2004 or from other parts of the watershed were available to use in the analyses in this report, they were used to help improve the quality of the evaluations.

3.1 Quality Assurance and Quality Control

All of the monitoring conducted by the UDWC Water Quality Monitoring Program is conducted under a State of Oregon approved Quality Assurance Project Plan (QAPP) (City of Bend, 2004). All data used in this report are considered to be “Grade B” or better per the ODEQ data quality matrix.1 In addition, the UDWC’s Water Quality Monitoring Program as a whole operates under a QAPP approved by ODEQ in 2002 and updated and reapproved in 2006 and 2008 (UDWC, 2002) (UDWC, 2006a) (UDWC, 2008). Coordinated monitoring efforts are carried out according to standard methods and protocols that are discussed in detail in the UDWC Water Quality Monitoring Program Standard Operating Procedures (UDWC, 2009).

The City of Bend Laboratory maintains accreditations and certifications by compliance with the relevant standards of operation, submission of acceptable performance evaluation test results, and undergoing periodic external audits by accrediting authorities. The laboratory is guided and evaluated by the U.S. Environmental Protection Agency, National Environmental Laboratory Accreditation Conference, Oregon Environmental Laboratory Accreditation Program, and ODEQ.

1 See: http://www.deq.state.or.us/lab/techrpts/docs/DEQ04‐LAB‐0003‐QAG.pdf

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Map 4. Study Area Water Quality Monitoring Stations

City of Bend Ambient Water Quality Monitoring Report 10

Map 5. City of Bend Ambient Water Quality Monitoring Stations within the Study Area

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3.2 Monitoring Stations and Parameters

The monitoring stations are listed in Tables 3 and 4. ODEQ has established reaches of the Upper Deschutes River and Tumalo Creek (named per river mile), and the City of Bend has multiple corresponding monitoring stations within each ODEQ reach. The City of Bend UGB extends from approximately river mile 172.00 to 163.25 on the Deschutes River. The monitoring focused on the following parameters:

Continuous monitoring parameters:

• Temperature, • Dissolved oxygen, • Percent saturation of dissolved oxygen, • Specific conductance, and • Turbidity

Grab sample monitoring parameters:

• ammonia‐N, • chloride, • fluoride, • sulfate, total Kjeldahl nitrogen, • nitrite‐N, • nitrate‐N, • nitrite/nitrate‐N, • total phosphorus, • orthophosphorus, • Escherichia coli, • chlorophyll a, and • pheophytin a.

When the monitoring project began in 2004, the monitoring also included total suspended solids, oil and grease, and the heavy metals lead, zinc and, copper. However, these parameters were discontinued for a variety of reasons. Total suspended solids and oil and grease were not monitored because the City of Bend Laboratory and UDWC agreed that the total suspended solids samples were difficult, time consuming and expensive to process, and the additional samples would not provide any new information. Oil and grease (that may escape if volatile), heavy metals, and nutrients are not found in the water rather they commonly accumulate within sediments. Lead, zinc, and copper were found to be non‐detectable in the water during monitoring in 2004 so were also not monitored after 2004. Other parameters were added to the monitoring effort due to the additional information their

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Table 3. ODEQ Reaches and Monitoring Stations on the Upper Deschutes River

Station ID Description ODEQ Reach River Mile

1 DR 250.50 d/s Little Lava Lake

2 DR 246.75 d/s Deschutes bridge at pullout by mm 42

3 DR 243.75 Cow camp 223.3 to 244.8

4 DR 243.50 u/s Crane Prairie 5 DR 237.50 d/s Browns Crossing

6 DR 226.75 d/s of USGS gaging station d/s Wickiup

7 DR 217.25 Pringle Falls Experimental Station 8 DR 207.25 Big Tree 189.5 to 220.0

9 DR 199.00 d/s General Patch Bridge

10 DR 192.75 u/s Little Deschutes River

11 DR 191.75 Harper Bridge

12 DR 181.50 Benham Falls Footbridge 168.2 to 189.4 13 DR 173.00 USFS Meadow Camp

14 DR 172.00 Southern UGB

15 DR 169.00 u/s end Mill Log Pond

16 DR 168.00 Columbia St. Bridge 17 DR 167.50 Colorado Street footbridge

18 DR 167.25 Columbia Park Footbridge 162.6 to 168.2

19 DR 166.75 Drake Park Footbridge 20 DR 166.00 u/s Portland Ave. Bridge

21 DR 165.75 First St. Rapids

22 DR 164.75 u/s Riverhouse Hotel 23 DR 163.25 Firerock footbridge

24 DR 160.25 u/s Tumalo Creek

25 DR 160.00 d/s Tumalo Boulder Field 26 DR 159.50 Tumalo Bridge

27 DR 158.50 d/s end Tumalo State Park

28 DR 150.75 White Rock Loop Rd, private ranch 126.4 to 162.7

29 DR 146.00 u/s Cline Falls State Park

30 DR 141.00 Tetherow Crossing

31 DR 133.50 Lower Bridge

32 DR 127.75 u/s Steelhead Falls

33 DR 123.25 u/s Whychus Creek

34 DR 123.00 d/s Whychus Creek

Note: Sites located within or adjacent to the City of Bend UGB are shown in bold.

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Table 4. ODEQ Reaches and Corresponding Monitoring Stations on Tumalo Creek

Station ID Description ODEQ Reach River Mile

1 TC 020.00 North and Middle Fork Confluence 2 TC 018.25 u/s of Tumalo Falls

3 TC 018.00 u/s of Bridge Creek 12.5 ‐ 17.1

4 TC 017.25 d/s of Bridge Creek 5 TC 014.50 d/s Skyliner Bridge

6 TC 007.50 upstream Road 4606 7 TC 003.25 d/s Tumalo Feed Canal Gage 0.0 ‐ 12.5 8 TC 000.25 Mouth 9 TCSF 000.25 South Fork Tumalo Creek at Mouth

assessment provides. These parameters include ammonia‐N, chloride, fluoride, sulfate, orthophosphorus, and pheophytin‐a. Monitoring parameters presented in this document are a result of an adaptive monitoring strategy that was based on periodic review of data (Jones, 2007) (Jones, L., 2008).

Continuously monitored parameters were collected via monitoring equipment that provides large datasets to compare to Oregon water quality standards or federal guidelines and provide important information about daily and seasonal fluctuations in water quality. Grab data collected under this study provide a snap shot in time of water quality status and focused on compounds that are valuable in assessing local stormwater influences on water quality within the urban reach of the Upper Deschutes River and along Tumalo Creek.

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4.0 Results: 303(d) List Parameters

This section focuses on reporting the status of temperature, dissolved oxygen, pH, sedimentation and turbidity, parameters that are 303(d) listed. Chlorophyll‐a, another parameter on the 303(d) list, is discussed separately in Section 5.3.

This section includes a brief introduction to each monitoring parameter followed by results and figures that illustrate the key findings. Whenever possible, state standards for water quality have been used to evaluate the status in the same way that the state evaluates listings for the 303(d) list. When a state standard is not available, federal guidance has been used to provide context.

Data were evaluated according to the methods described in the state of Oregon Assessment Methodology for Oregon’s 2004/2006 Integrated Report on Water Quality Status (ODEQ, 2006). It is important to note that (a) ODEQ is prioritizing the next 303(d) list assessment and data review on toxics data and not other data such as dissolved oxygen, and (b) continuous data has not been used in the past 303(d) assessments due to difficulty in determining a good statistical measure (Lamb, 2009).

4.1 Temperature

4.1.1 Background

Water temperature naturally fluctuates on both a daily and seasonal basis. Daily fluctuations are usually the result of the continuous changes in solar radiation and air temperatures. Seasonal fluctuations are often a response to changes in climate, solar aspect, and to variable amounts of stream flows from snowmelt and precipitation. Water temperatures naturally increase as water flows downstream and water temperatures can decrease as a result of groundwater inflows (springs) or the inflow of cooler tributaries.

Fish and aquatic life are sensitive to increases in temperature because growth, metabolism, reproduction and other key functions can be affected by the surrounding water temperature. The state of Oregon has set temperature standards as follows (ODEQ, 2009):

• Salmon and trout rearing and migration temperatures are not to exceed a seven day moving average maximum (7DMAX) temperature of 18 °C / 64 °F. This standard applies all year. • Bull trout spawning and rearing temperatures are not to exceed 12 °C / 54 °F 7DMAX. This standard applies between August 15 and June 15. • Lethal temperatures for salmon and trout are above 24 °C / 75 °F (ODEQ, 1995).

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The High Lakes, Upper, and Middle reaches of the Upper Deschutes River are identified for salmon and trout rearing and migration (18 °C / 64 °F). The High Lakes reach is additionally identified for bull trout spawning and rearing (12 °C / 54 °F) between August 15 and June 15. The Upper and Middle reaches of the Upper Deschutes River are currently 303(d) listed for not meeting salmon and trout rearing and migration standards while the High Lakes reach is listed for not meeting bull trout spawning and rearing standards.

All of Tumalo Creek is identified for salmon and trout rearing and migration (18 °C / 64 °F). In addition, the upper reach of Tumalo Creek (above river mile 12.5) is identified for bull trout spawning and rearing (12 °C / 54 °F) between August 15 and June 15. The lower 12.5 miles of Tumalo Creek is currently 303(d) listed for not meeting salmon and trout rearing and migration temperature standards.

4.1.2 Upper Deschutes River

The monitoring data from this study was combined with regional data to provide a comprehensive summary of water temperature through the City of Bend. The resulting temperature dataset extends back to 1997.

Figure 1 displays all of the temperature data compiled by the UDWC WQ Monitoring Program. Continuous temperature, expressed as the seven day moving average maximum degree Celsius (°C), was collected at 39 monitoring stations, yet not all stations were monitored each year. From 1997 through 2008, each year displays summer temperatures that are elevated above the state of Oregon temperature standard of 18 °C / 64 °F for salmon and trout rearing and migration. The warmest stream temperatures are typically observed during the summer months of July and August when agricultural use of water is high and the solar radiation and air temperatures are at their peak. Figure 2 displays a subset of these data for the City of Bend monitoring sites that are the focus of this report.

Temperatures above the state temperature standard for salmon and trout rearing and migration occur predominately in the High Lakes Reach, the lower end of the Upper Reach (downstream of river mile 172), and the Middle Reach of the Deschutes River. There are no data for the Middle Reach of the Deschutes River (downstream of river mile 160) until 2001 when ODEQ implemented data collection for TMDL development for the Upper Deschutes River and the UDWC WQ Monitoring Program started coordinating water quality monitoring in the Upper Deschutes and Little Deschutes Subbasins.

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Figure 1. Upper Deschutes River Seven Day Moving Average Maximum Temperature 1997 – 2008

DR 250.50 DR 247.75 Deschutes River Temperatures 1997 ‐ 2008 DR 246.75 DR 243.75 DR 237.50 30 DR 226.75 28 DR 217.25 DR 207.25 26 DR 199.00 24 DR 192.75 DR 191.75 Temperature 22 DR 181.50 20 DR 173.00 DR 172.00 (C)

18 DR 169.00 DR 168.00

Maximum 16 DR 167.50

Celsius 14 DR 167.25 DR 166.75 12 DR 166.00 Average 10 DR 165.75 Degree DR 164.75 8 DR 163.25 DR 160.25

Moving 6 DR 160.00 4 DR 159.50 Day 2 DR 158.50 DR 150.75 0 DR 146.00

Seven DR 141.00 97 98 99 00 01 02 03 04 05 06 07 08 09

‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ DR 133.50 DR 127.75 DR 123.25 DR 123.00 January January January January January January January January January January January January January Criteria

Every year in which data was collected for the Middle Reach of the Deschutes River, except 2008, temperatures reach the lethal level of 24 °C / 75 °F at some point in the river system (Figure 1) (ODEQ, 1995). In 2003, temperatures were above the lethal level in the High Lakes reach of the Deschutes River. Year to year, temperature was relatively constant downstream of Wickiup Reservoir (river mile 220 – 180) because temperatures are controlled by high reservoir release flows (approximating 1900 cfs) from a cool temperature, mid‐reservoir depth (Breuner, 2003) (USBR, 2003).

City of Bend Ambient Water Quality Monitoring Report 17

Figure 2. City of Bend Area Seven Day Moving Average Maximum Temperature 1997 – 2008

City of Bend Monitoring Deschutes River DR 173.00 1997 ‐ 2008 DR 172.00 24 DR 169.00

22 DR 168.00 20

Temperature DR 167.50 18 16 DR 167.25 (C)

Maximum DR 166.75

Celsius 12

10 DR 166.00 Average

Degree 8 DR 165.75 6 DR 164.75 Moving 4

Day DR 163.25 2

0 DR 160.25 Seven 97 98 99 00 01 02 03 04 05 06 07 08 09 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ DR 160.00

Criteria January January January January January January January January January January January January January

Figure 3 displays a plot of the longitudinal profile of temperatures in the Deschutes River on July 7, 2007, the hottest day of 2007 and 2008. Temperatures exceeded the 18°C / 64 °F state temperature standard in the High Lakes reach of the Deschutes River (temperature reached up to 24 °C / 75 °F) and in the Middle Reach (temperature reached up to 26 °C / 79 °F). Relatively constant temperatures are observed downstream of Wickiup Reservoir (river mile 220 – 180) because temperatures are controlled by high reservoir release flows (approximating 1900 cfs) from a cool temperature, mid‐reservoir depth (Breuner, 2003) (USBR, 2003). Figure 4 illustrates the City of Bend area in more detail.

Figure 5 illustrates the rate of change in temperature per river mile along the longitudinal extent of the Deschutes River between Lava Lake and the confluence with Whychus Creek. Although temperatures are expected to increased gradually as the river flows downstream, this illustration is useful in identifying locations along the river where the temperature increases or decrease rapidly, potentially indicating sources of natural or unnatural changes in temperature.

City of Bend Ambient Water Quality Monitoring Report 18

Figure 3. Upper Deschutes River Hottest Seven Day Moving Average Maximum Temperature by River Mile

Seven Day Moving Average Maximum Temperature 7/7/2007 Criteria

River Mile Degree

251.25 246.00 241.00 236.00 231.00 226.00 221.00 216.00 211.00 206.00 201.00 196.00 191.00 186.00 181.00 176.00 171.00 166.00 161.00 156.00 151.00 146.00 141.00 136.00 131.00 126.00 121.00 30 28 26 Temperature 24 22 (C) 20 Maximum

Celsius 16 14 Average

12 10 8 Moving 6 Day ‐ Springs Fall River Fall Seven Spring River City S. UGB City City N. UGB City Crane Prairie Tumalo Creek Wickiup Outlet Lower Brdg Rd Lower Whychus Creek Whychus Lava LakeOutlet

The High Lakes, Upper, and Middle reaches of the Deschutes average rate of temperature change per mile is 0.4, 0.0, and ‐0.1 °C (0.7, 0.0, and ‐0.2 °F), respectively. Natural drivers of temperature change are likely the cool waters originating from Lava Lake, the steady temperature conditions downstream of Fall River and Spring River, and the rapid rate of cooling downstream of the springs near Lower Bridge Road that results in significant temperature reduction of 1.4 °C / 2.5 °F per mile. Increased warming rates are observed downstream of Crane Prairie Reservoir, at the four impoundments within the City of Bend, and downstream of the primary irrigation diversions at North Canal Dam. The observed warming rates are consistent with the anticipated effects of the impoundments at Crane Prairie and in the City of Bend, and with the reduced flow conditions downstream of the irrigation diversions in Bend. At Lower Bridge Road, Figure 5 illustrates that temperatures appear to be increasing despite temperatures already being approximately 26 °C / 79 °F.

City of Bend Ambient Water Quality Monitoring Report 19

Figure 4. City of Bend Area Hottest Seven Day Moving Average Maximum Temperature by River Mile

Seven Day Moving Average Maximum Temperature 7/7/2007 Criteria

River Mile 175.00 174.00 173.00 172.00 171.00 170.00 169.00 168.00 167.00 166.00 165.00 164.00 163.00 162.00 161.00 160.00 159.00 30 Temperature

28 26

22 Maximum 20 Celsius 18 16 Average

Degree 14 12 Moving

10 8 Day ‐ 6 Seven Mirror Pond City S. UGB City City N. UGB City Tumalo Creek North Canal Dam

City of Bend Ambient Water Quality Monitoring Report 20

Figure 5. Upper Deschutes River Rate of Temperature Change on the Hottest Day

Above Average Rate of Temperature Change Below Average Rate of Temperature Change Average Rate of Temperature Change River Mile

Average ‐1.5

‐2 ‐2.5 Degree Moving

‐3 ‐3.5 Day ‐4 Seven

Springs Fall River Fall City N. UGB City Spring River City S. UGB City Crane Prairie Tumalo Creek Wickiup Outlet Lower Brdg Rd Lower Whychus Creek Whychus Change Lava LakeOutlet

City of Bend Ambient Water Quality Monitoring Report 21

Figure 6. City of Bend Area Deschutes River Rate of Temperature Change on the Hottest Day

Above Average Rate of Temperature Change Below Average Rate of Temperature Change Average Rate of Temperature Change

River Mile 175.00 174.00 173.00 172.00 171.00 170.00 169.00 168.00 167.00 166.00 165.00 164.00 163.00 162.00 161.00 160.00 159.00 Temperature 2 1.5 1 0.5 Maximum

(C)

0 ‐0.5 ‐1 Celsius Average

‐1.5 ‐2 ‐2.5 Degree Moving

‐3 ‐3.5 Day ‐4 Seven

Mirror Pond City N. UGB City City S. UGB City Tumalo Creek Change North Canal Dam

City of Bend Ambient Water Quality Monitoring Report 22

4.1.3 Tumalo Creek

The monitoring data collected along Tumalo Creek was combined with regional data, resulting in a data set that extends back to 1995. As noted earlier, there are two temperature standards in place for Tumalo Creek:

• The entire longitudinal extent of Tumalo Creek is identified for salmon and trout rearing and migration, resulting in a temperature standard of 18 °C / 64 °F. • The upper reach of Tumalo Creek (above river mile 12.5) is identified for bull trout spawning and rearing, resulting in a temperature standard of 12 °C / 54 °F.

The existence of a bull trout standard in Tumalo Creek is somewhat unusual because there is general agreement among state and federal fisheries managers that bull trout do not currently exist in Tumalo Creek and are not likely to be reintroduced. Nevertheless, this purpose of this report is to compare data to existing standards, not to comment on the standards. Therefore, temperature data are compared to the existing standards, including the bull trout standard, because these standards are currently in place.

Figure 7 displays 1995 to 2008 temperature data compiled by the UDWC WQ Monitoring Program compared to the state temperature standards that are applicable to the entire creek system. The continuous temperature, expressed as the seven day moving average maximum (7DMAX) °C, was collected at nine monitoring stations, yet not all stations were monitored each year. There is less data collected prior to 2001 compared to the time period post 2001. In 2001, ODEQ implemented data collection for TMDL development for Tumalo Creek and the UDWC WQ Monitoring Program started coordinating water quality monitoring in the Upper Deschutes and Little Deschutes Subbasins. All years since 2001 display summer temperatures on the main stem of Tumalo Creek that are elevated above the 18 °C / 64 °F. state of Oregon temperature standard for salmon and trout rearing and migration. The South Fork of Tumalo Creek meets state temperature standards for salmon and trout rearing and migration. The warmest stream temperatures are typically observed during the summer months when diversions are at their peak and the solar radiation and air temperatures are highest. Within Tumalo Creek, temperatures do not reach the lethal level of 24 °C / 75 °F for salmon and trout rearing and migration (ODEQ, 1995).

Figure 8 displays the 1995 to 2008 temperature data compiled by the UDWC WQ Monitoring Program compared to the state temperature standard set to protect bull trout spawning and rearing that applies only upstream of river mile 12.5. Continuous temperature, expressed as the seven day moving average maximum degree Celsius, was collected at five monitoring stations within the bull trout spawning and rearing designated reach of Tumalo Creek, yet not

City of Bend Ambient Water Quality Monitoring Report 23

all stations were monitored each year. Temperatures along the main stem of Tumalo Creek were elevated above the state of Oregon temperature standard for bull trout spawning and

Figure 7. Tumalo Creek Temperature Compared to Salmon and Trout Standards

Tumalo Creek Temperatures 1995 ‐ 2008

30 28 TC 020.00 26 24 Temperature 22 TC 018.25 20 18 Maximum

16 Celsius

14 TC 018.00 12 Average

Degrees 10 8 TC 017.25 Moving 6

Day 4

2 TC 014.50 Seven 0 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐

January January January January January January January January January January January January January January January January

rearing in all years since 1995 (excluding 1996 when no data were collected). The South Fork of Tumalo Creek meets state temperature standards for bull trout spawning and rearing.

Figure 9 display a plot of the longitudinal profile of temperatures in Tumalo Creek on July 7, 2007, the hottest day of 2007 and 2008. Temperatures reached approximately 21 °C / 70 °F near the mouth of Tumalo Creek, exceeding the state standard set to protect salmon and trout rearing and migration.

Figure 10 provides an illustration of the rate of change in the temperature per river mile along the longitudinal extent of Tumalo Creek. The average rate of temperature change per mile for Tumalo Creek is 0.4 °C / 0.7 °F. There are two stations that reflect no rate of change or a cooling rate of change and one station that reflects a warming rate of change. The cooling is

City of Bend Ambient Water Quality Monitoring Report 24

likely the result of spring inflows whereas the warming is likely the result of irrigation withdrawals at the Tumalo Feed Canal diversion at approximately river mile 3.5.

Figure 8. Tumalo Creek Temperature Compared to Bull Trout Standards

Tumalo Creek Upper Reach Temperatures 1995 ‐ 2008 30 28 26 24

Temperature 22

TC 020.00 20 18 16 TC 018.25 Maximum

Celsius 14 12 TC 018.00

Average 10

Degrees 8 6 Moving 4

Day 2

0 Seven 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐

January January January January January January January January January January January January January January January January

City of Bend Ambient Water Quality Monitoring Report 25

Figure 9. Tumalo Creek Hottest Seven Day Moving Average Maximum Temperature by River Mile

Seven Day Moving Average Maximum Temperature 7/7/2007

Salmon and Trout Criteria (18C) River Mile 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 20.00 19.00 18.00 17.00 16.00 15.00 14.00 13.00 12.00 11.00 10.00 30 Temperature

28 26 24 (C) 22 Maximum

Celsius 18

Average 14

Degree 12 10

Moving 8

6 Day ‐ Mouth Seven Road 4606 Tumalo Falls Tumalo Bridge Creek N.F. and S.F. OWRD Gage Shevlin Road Tumalo Creek Skyliners Road Skyliners TID Canal Feed S.F. Tumalo Creek

City of Bend Ambient Water Quality Monitoring Report 26

Figure 10. Tumalo Creek Rate of Temperature Change on the Hottest Day

Above Average Rate of Temperature Change Below Average Rate of Temperature Change Average Rate of Temperature Change

River Mile 20.00 19.00 18.00 17.00 16.00 15.00 14.00 13.00 12.00 11.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 Temperature 2 1.5 1 Maximum

‐0.5 ‐1 Degree Moving ‐1.5 Day ‐2 Seven

Mouth in

Road 4606 N.f. and SF Tumalo Falls Tumalo Bridge Creek Shevlin Road OWRD Gage Tumalo Creek Skyliners Road Skyliners TID Canal Feed Change S.F. Tumalo Creek

Figure 11 illustrates the longitudinal profile of temperatures in Tumalo Creek on August 15, 2007, the hottest water day for Tumalo Creek during the time period designated for potential bull trout spawning and rearing in 2007 and 2008. Temperatures exceeded the state temperature standard at river mile 14.5.

Figure 12 shows that the average rate of temperature change per mile for Tumalo Creek during bull trout spawning and migration is 0.5 °C / 0.9 °F.

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Figure 11. Tumalo Creek Hottest Water Day during Bull Trout Spawning and Migration

Seven Day Moving Average Maximum Temperature 8/15/2008

Bull Trout Criteria (12C)

River Mile 20.00 19.75 19.50 19.25 19.00 18.75 18.50 18.25 18.00 17.75 17.50 17.25 17.00 16.75 16.50 16.25 16.00 15.75 15.50 15.25 15.00 14.75 14.50 14.25 14.00 30 28 26 Temperature 24 22 (C) 20 18 Maximum 16 Celsius 14 12 Average 10 Degree 8 6 Moving

Day ‐ Bridge Creek Seven Tumalo Falls Tumalo N.F. and M.F. Tumalo Creek Skyliners Road Skyliners S.F. Tumalo Creek

City of Bend Ambient Water Quality Monitoring Report 28

Figure 12. Tumalo Creek Rate of Temperature Change during Bull Trout Spawning and Migration

Above Average Rate of Temperature Change Below Average Rate of Temperature Change

Average Rate of Temperature Change

River Mile 20.00 19.75 19.50 19.25 19.00 18.75 18.50 18.25 18.00 17.75 17.50 17.25 17.00 16.75 16.50 16.25 16.00 15.75 15.50 15.25 15.00 14.75 14.50 14.25 14.00 Temperature 5 4 3 2 Maximum

1 (C) 0 ‐1 ‐2 Celsius Average

‐3 ‐4 ‐5 ‐6 Degree Moving

‐7 ‐8

Day ‐9 ‐10 Seven

Tumalo Falls Tumalo Bridge Creek N.F. and M.F. Tumalo Creek Skyliners Road Skyliners Change S.F.Tumalo Creek

City of Bend Ambient Water Quality Monitoring Report 29

4.2 Upper Deschutes River Dissolved Oxygen

4.2.1 Background

Dissolved oxygen is the concentration of oxygen in the water. The concentration of dissolved oxygen within the waterway undergoes daily fluctuations as primary producers photosynthesize and aquatic organisms degrade compounds. During the day, aquatic plants utilize photosynthesis and produce oxygen. During the day and night, respiration and aerobic redox reactions that decompose organic and inorganic matter consume oxygen. The balance between photosynthesis that produces oxygen and respiration and decomposition that consume oxygen affects the amount of dissolved oxygen levels in the waterway.

The concentration of dissolved oxygen within the waterway also undergoes seasonal fluctuations. Warmer temperatures during summer months increase the rates of photosynthesis and decomposition. As plants die at the end of the season, decomposers consume oxygen to break down the organic plant compounds. This results in a seasonal fluctuation in dissolved oxygen concentrations. In a healthy waterway, a balance between consumers and producers exists and aquatic organisms acclimate to the daily and seasonal fluctuations in dissolved oxygen and its percent saturation.

Percent saturation is the amount of oxygen that can be held within the water. The percent saturation within the waterway is affected by temperature and altitude. Cold water holds more dissolved oxygen than warm water. Water at higher altitudes holds less dissolved oxygen than water at lower altitudes, because atmospheric pressure is lower at higher altitudes.

Aquatic organisms are affected by the fluctuations in dissolved oxygen within the waterway. If oxygen is consumed at a faster rate than it is produced, dissolved oxygen levels decrease and aquatic organisms can be negatively affected. Salmon and trout, especially in their early life stages, are very susceptible to low dissolved oxygen concentrations.

The state of Oregon has set dissolved oxygen standards as follows:

• Salmon and trout non‐spawning dissolved oxygen concentrations and percent saturations are not to drop below 8.0 mg/L and 90% saturation. This standard applies all year round. • Salmon and trout spawning dissolved oxygen concentrations and percent saturations are not to drop below 11.0 mg/L and 95% saturation. This standard applies January 1 – May 15.

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4.2.2 Status

The 303(d) listing of dissolved oxygen impairment on the Upper and Middle reaches of the Deschutes River is based on data collected in 2001 – 2006. The status of dissolved oxygen concentrations in 2007 – 2008 is of interest because it includes data that is more recent than the data available from the state.

In order for data to qualify for 303(d) listing evaluation, at least five measurements must be collected on different days in one season and at least 10% of the samples collected must not meet the standard in order for the waterway to be considered impaired (ODEQ, 2006).

Continuous Data Continuous dissolved oxygen data from 2001 – 2008 are presented in Figure 13, illustrating daily mean dissolved oxygen as the statistic used to evaluate continuous dissolved oxygen data against the state standard (ODEQ, 2006). Specific sites located within the City of Bend UGB are presented in Figure 14. Monitoring stations and time periods that fall outside the state criteria are presented in more detail in Figures 15 and 16.

The Middle reach of the Deschutes River downstream of Tumalo Boulder Field (DR 160.00) falls below the spawning standard during 2007 – 2008 (Figure 15). For this evaluation, continuous dissolved oxygen data are used to calculate the daily mean dissolved oxygen concentration, which is compared to the state dissolved oxygen standard for salmon and trout spawning 2007 – 2008 of 11.0 mg/L (ODEQ, 2006). The Middle reach of the Deschutes River downstream of the Tumalo boulder field (DR 160.00) is the only station that meets the minimum sample requirement during the 2007 – 2008 salmon and trout spawning time periods. Dissolved oxygen concentrations do not meet state standards for dissolved oxygen during 2007 on the Middle reach of the Deschutes River downstream of the Tumalo boulder field (DR 160.00).

City of Bend Ambient Water Quality Monitoring Report 31

Figure 13. Upper Deschutes River Daily Mean Dissolved Oxygen 2001 – 2008

Dissolved Oxygen 2001 ‐ 2008 15.0 DR 237.50

14.0 DR 226.75 13.0

(mg/L) DR 191.75 12.0 DR 172.00 11.0 Oxygen

10.0 DR 166.75

9.0 Dissolved

DR 164.75 8.0 Mean

DR 160.00 7.0

Daily DR 133.50 6.0

5.0 Criteria 01 02 03 04 05 06 07 08 09 10 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ January January January January January January January January January January

City of Bend Ambient Water Quality Monitoring Report 32

Figure 14. City of Bend Area Upper Deschutes River Daily Mean Dissolved Oxygen 2001 – 2008

Dissolved Oxygen 2001 ‐ 2008 15.0 DR 172.00 14.0

13.0 (mg/L) DR 166.75 12.0

11.0 Oxygen

10.0 DR 164.75

9.0 Dissolved

8.0 DR 160.00 Mean

7.0 Daily 6.0 Criteria 5.0 01 02 03 04 05 06 07 08 09 10 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ January January January January January January January January January January

City of Bend Ambient Water Quality Monitoring Report 33

Figure 15. Upper Deschutes River Daily Mean Dissolved Oxygen Spawning 2007 – 2008

Deschutes River Dissolved Oxygen Spawning 2007 ‐ 2008 15

13 (mg/L) 12

11 11 Oxygen

9 Dissovled

8 Mean

7 Daily 6

5 DR 160.00 2007

Station ID Sample Size 10% median 90% Percentile Range

DR 160.00 25 10.1 11.1 11.3 1.2

Because dissolved oxygen concentrations do not meet state standards for dissolved oxygen during 2007 on the Middle reach of the Deschutes River downstream of the Tumalo boulder field (DR 160.00), percent saturation of dissolved oxygen is used to evaluate the data against the state standard (Table 5). The state of Oregon dissolved oxygen standard for the salmon and trout spawning time period is 11 mg/L and 95% saturation dissolved oxygen. In 2007, there are more than ten samples from the Middle reach of the Deschutes River downstream of the Tumalo boulder field, of which six of the samples did not meet the state minimum dissolved oxygen concentration and percent saturation standard set to protect salmon and trout spawning.

City of Bend Ambient Water Quality Monitoring Report 34

Table 5. Upper Deschutes River Dissolved Oxygen Spawning Exceedences 2007 – 2008

DR 160.00 Daily Mean DO (mg/L) Daily Mean % Sat

4/6/2007 10.5 92.5 4/7/2007 10.4 92.1 4/8/2007 10.7 92.9 4/9/2007 10.9 93.7 4/14/2007 10.9 94.2 5/10/2007 10.0 94.0

There are four stations in 2007 – 2008 that have enough continuous data for analyses of dissolved oxygen against the state of Oregon minimum dissolved oxygen standard of 8.0 mg/L set to protect salmon and trout rearing and migration (Figure 16). Two stations on the Upper reach of the Deschutes River (i.e., City of Bend southern urban growth boundary [DR 172.00] and Drake Park Footbridge [DR 166.75]) and two stations on the Middle Reach of the Deschutes River (i.e., downstream of the Tumalo boulder field [DR 160.00] and at Lower Bridge Road [DR 133.50]) have enough data. Dissolved oxygen concentrations meet the state standard for dissolved oxygen during 2007 – 2008 at all four of these stations.

City of Bend Ambient Water Quality Monitoring Report 35

Figure 16. Upper Deschutes River Daily Mean Dissolved Oxygen Non‐Spawning 2007 – 2008

Dissolved Oxygen Rearing and Migration 2007 ‐ 2008 15

13 (mg/L) 12

11 Oxygen

9 Dissolved

8 8 Mean

7 Daily 6

5 DR 172.00 DR 166.75 DR 160.00 DR 133.50

Station ID Sample Size 10% Median 90% Percentile Range

DR 172.00 52 8.9 9.1 9.4 0.5 DR 166.75 110 8.7 9.1 11.0 2.4 DR 160.00 102 8.6 9.6 11.0 2.4 DR 133.50 54 8.0 9.5 12.0 3.9

Grab Sample Data Grab samples do not provide the daily fluctuations in dissolved oxygen, but they are a good way to assess the need for continuous monitoring that can capture daily and seasonal fluctuations in dissolved oxygen. The results presented in Figures 17 and 18 provide some insight into additional data collection needs.

In Figure 17, concentrations of dissolved oxygen grab samples collected along the longitudinal extent of the Upper Deschutes River 2007 – 2008 are compared to the state of Oregon minimum dissolved oxygen standard of 11.0 mg/L for salmon and trout spawning time periods. Although there are not enough grab samples to formally evaluate these data using the state assessment methodology, several stations within the Upper and Middle reaches of the Deschutes River are below the state standard set to protect salmon and trout spawning time periods.

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Even though the data do not permit a formal evaluation, the results presented in Figure 17 suggest that continuous monitoring should be conducted to allow a formal evaluation of the dissolved oxygen concentrations relative to the state standard. Although past continuous monitoring has been conducted at some of the sites included in Figure 17, the monitoring has not occurred early enough in the year to be included in the spawning season evaluation. Therefore, additional monitoring should be conducted early in the season (e.g., starting April 1) at the following sites: upstream of the City of Bend (DR 172.00), downstream of the Tumalo boulder field (DR 166.75) and at Lower Bridge Road (DR 133.50). Additional upstream sites could also be added to provided better upstream context (e.g., Pringle Falls and Benham Falls).

Figure 17. Upper Deschutes River Grab Dissolved Oxygen Spawning 2007 ‐2008

Deschutes River; Spawning 2007 ‐ 2008 May‐08

14 Apr‐08 13 12

(mg/L) Mar‐08 11 10 Oxygen 9 May‐07 8 Dissoved 7 Apr‐07 6 5 Mar‐07 75 25 . . ODEQ UDWC UDWC

191 191 75 UDWC 160 25

DR DR DR 168.00 DR 167.25 DR 163.25 DR 166.75 DR 164.75 DR 172.00 DR 160.00 DR DR 181.50 DR 169.00 DR 165.75 DR 123.00 Criteria spawning City of Bend Area 133.50 133.50 (11 mg/L) DR 217.25 ODEQ DR 133.50 DR DR DR 217.25

City of Bend Ambient Water Quality Monitoring Report 37

Figure 18 presents concentrations of dissolved oxygen grab samples collected along the longitudinal extent of the Upper Deschutes River 2007 – 2008 compared to the state of Oregon minimum dissolved oxygen standard of 8.0 mg/L for salmon and trout non‐spawning time periods. Although there are not enough grab samples to formally evaluate these data using the state assessment methodology, the data suggest that all of the stations meet the state standards established to protect salmon and trout non‐spawning time periods.

Figure 18. Upper Deschutes River Grab Dissolved Oxygen Non‐Spawning 2007 – 2008

Deschutes River; Non‐Spawning 2007 ‐ 2008 Nov‐08

15 Oct‐08 14 Sep‐08 13 12 Aug‐08 (mg/L)

11 Jul‐08 10 Oxygen Jun‐08 9 8 Oct‐07 Dissoved 7 Sep‐07 6 5 Aug‐07 25 75 . . Jul‐07 ODEQ UDWC UDWC

UDWC

160 25 191 191 75

DR 167.25 DR 169.00 DR 165.75 DR 163.25 DR 166.75 DR DR 160.00 DR 123.00 DR 181.50 DR 172.00 DR 164.75 DR DR DR 168.00 Jun‐07 133.50 DR 217.25 ODEQ DR 133.50

City of Bend Area DR DR 217.25 Criteria Non‐ Spawning (8 mg/L)

City of Bend Ambient Water Quality Monitoring Report 38

4.3 Upper Deschutes River pH

4.3.1 Background

The measure of pH is the hydrogen ion concentration of a solution using a logarithmic scale of 0.0 to 14.0. Low pH (i.e., less than 7.0) is considered acidic while high pH (i.e., greater than 7.0) is alkaline. Water pH can have both direct and indirect effects on the aquatic ecosystem. In general, aquatic organisms do best in a water pH range of 6.5 to 8.5. Water pH can impact both aquatic insect populations and salmon and trout by affecting egg development, egg hatching, and embryo development. Extreme pH levels can affect the availability and toxicity of certain pollutants such as heavy metals and ammonia.

Like temperature and dissolved oxygen, pH naturally varies both daily and seasonally. Daily fluctuations in pH are usually the result of the photosynthetic activity of aquatic plants. During the day when aquatic plants uptake carbon dioxide and release oxygen, the water becomes more alkaline (i.e., pH values increase). Conversely, during the night when plants are not actively photosynthesizing yet other aquatic organisms are producing carbon dioxide via respiration, the water becomes more acidic (i.e., pH values decrease). The daily peak in pH values typically occurs in the mid to late afternoon while the lowest values occur just before sunrise. Seasonal fluctuations in pH are also due to the differences in the photosynthetic activity of aquatic plants, and fluctuations are affected by increased primary production during the summer and decreased primary production during the winter.

The state of Oregon has set the year‐round pH standard at 6.5 to 8.5.

4.3.2 Status

The 303(d) listing of pH impairment on the Upper and Middle reaches of the Upper Deschutes River reflects the maximum pH values collected in 2001 – 2006 and does not reflect the minimum pH values collected. The status of pH in 2007 – 2008 is of interest because it represents results that are more recent than those provided by the state.

In order to formally evaluate the 303(d) status relative to state standards, at least five measurements must be collected on different days in one season and at least 10% of the samples collected must not meet the standard in order for the waterway to be considered impaired (ODEQ, 2006).

City of Bend Ambient Water Quality Monitoring Report 39

Continuous Data Figure 19 includes the daily maximum pH from 2001 – 2008. Daily maximums were derived from continuous data and are shown relative to the state standard of 8.5. (ODEQ, 2006). Figure 20 includes the subset of data from the City of Bend area.

Figure 19. Upper Deschutes River Daily Maximum pH 2001 – 2008

Daily Maximum pH 2001 ‐ 2008 DR 237.50 10.0 DR 226.75 9.5

9.0 DR 191.75 8.5 (SU) 8.0 DR 172.00 Unit

7.5 DR 166.75 7.0 Standard

pH 6.5 DR 164.75 6.0

5.5 DR 160.00

5.0 DR 133.50 00 01 02 03 04 05 06 07 08 09 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐

Criteria January January January January January January January January January January

City of Bend Ambient Water Quality Monitoring Report 40

Figure 20. City of Bend Area Upper Deschutes River Daily Maximum pH 2001 – 2008

City of Bend Daily Maximum pH 2001 ‐ 2008 DR 172.00 10.0

9.5

9.0 DR 166.75 8.5 (SU) 8.0 Unit

7.5 DR 164.75 7.0 Standard

pH 6.5

6.0 DR 160.00 5.5

5.0 00 01 02 03 04 05 06 07 08 09 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Criteria January January January January January January January January January January

Figure 21 includes the daily minimum pH from 2001 – 2008 relative to the state standard of 6.5 established to salmon and trout spawning, rearing, and migration. The state of Oregon 303(d) listing of pH impairment on the Upper and Middle reaches of the Deschutes River does not reflect the minimum pH values collected in 2001 – 2006. The status of pH in 2007 – 2008 is of interest because it illustrates values that exceed the state standard (see discussion below).

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Figure 21. Upper Deschutes River Daily Minimum pH 2001 – 2008

Daily Minimum pH 2001 ‐ 2008

10.0 DR 237.50 9.5 DR 226.75 9.0 DR 191.75 8.5 (SU)

8.0 DR 172.00 Unit

7.5 DR 166.75

7.0

Standard DR 164.75

pH 6.5 DR 160.00 6.0 DR 133.50 5.5

5.0 Criteria 00 01 02 03 04 05 06 07 08 09 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ January January January January January January January January January January

City of Bend Ambient Water Quality Monitoring Report 42

Figure 22. City of Bend Area Upper Deschutes River Daily Minimum pH 2001 – 2008

City of Bend Daily Minimum pH 2001 ‐ 2008 10.0 DR 172.00 9.5

9.0

8.5 DR 166.75 (SU)

8.0 Unit

7.5 DR 164.75

7.0 Standard

pH 6.5 DR 160.00 6.0

5.5 Criteria 5.0 00 01 02 03 04 05 06 07 08 09 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ January January January January January January January January January January

Of the data available, there are four stations in 2007 – 2008 that have enough continuous data for formal analyses of pH against the state of Oregon maximum pH of 8.5 set to protect multiple beneficial uses over two seasons during 2007 ‐ 2008 (i.e., fall/winter/spring and summer) (Figure 23). These stations include the Deschutes River at the City of Bend southern urban growth boundary (DR 172.00), Drake Park Footbridge (DR 166.75), downstream of Tumalo boulder field (DR 160.00), and Lower Bridge Road (DR 133.50).

City of Bend Ambient Water Quality Monitoring Report 43

Figure 23. Upper Deschutes River Daily Maximum pH 2007 – 2008

Daily Maximum pH 2007 ‐ 2008 10

8.5 Units

8 Standard

7 City of Bend Area

6 DR 172.00 DR 166.75 DR 160.00 DR 133.50

Station ID Sample Size 10% 90% Maximum Percentile Range

DR 172.00 141 7.8 8.7 9.1 0.9 DR 166.75 124 8.1 8.7 9.3 0.6 DR 160.00 95 7.9 8.6 9.0 0.7 DR 133.50 58 8.1 8.9 9.0 0.9

Based on this analysis, the following do not meet the state maximum pH standard:

• Summer 2007: Upper reach of the Deschutes River at Drake Park Footbridge (DR 166.75), Middle reach of the Deschutes River at Tumalo boulder field (DR 160.00) and Lower Bridge Road (DR 133.50); • Fall 2007: The Upper reach of the Deschutes River at the City of Bend southern urban growth boundary (DR 172.00); and • Summer 2008: The Upper reach of the Deschutes River at Drake Park Footbridge (DR 166.75), the Middle reach of the Deschutes River at the Tumalo boulder field (DR 160.00), and Lower Bridge Road (DR 133.50).

There are four stations in 2007 – 2008 that have enough continuous data for analyses of pH against the state of Oregon minimum pH standard of 6.5 established to protect multiple beneficial uses of the water over two seasons (i.e., fall/winter/spring and summer) (Figure 24). These stations include the Deschutes River at the City of Bend southern UGB (DR 172.00), Drake

City of Bend Ambient Water Quality Monitoring Report 44

Park Footbridge (DR 166.75), downstream of the Tumalo boulder field (DR 160.00), and Lower Bridge Road (DR 133.50).

Figure 24. Upper Deschutes River Daily Minimum pH 2007 – 2008

Daily Minimum pH 2007 - 2008 10

City of Bend Area

9 Units

8 Standard

6.5

6 DR 172.00 DR 166.75 DR 160.00 DR 133.50

Station ID Sample Size Minimum 10% 90% Percentile Range

DR 172.00 141 6.9 7.1 7.8 0.7 DR 166.75 124 7.5 7.5 7.7 0.1 DR 160.00 95 6.8 7.4 7.8 0.4 DR 133.50 58 6.8 6.9 7.5 0.6

Based on these results, all of the sites presented in Figure 24 meet the state minimum pH standard during 2007 – 2008.

Grab Sample Data Although grab samples do not provide the daily fluctuations in pH, they are a good way to assess the need for potential continuous monitoring. Figure 25 presents the results of pH grab samples collected along the longitudinal extent of the Upper Deschutes River in 2007 – 2008 compared to the state of Oregon minimum and maximum pH standard of 6.5 and 8.5, respectively. Although there are not enough grab samples to formally evaluate the data using the state assessment methodology, the data suggest that the Upper reach of the Deschutes River at Benham Falls (DR 181.50) and the Middle reach of the Deschutes River at Lower Bridge

City of Bend Ambient Water Quality Monitoring Report 45

(DR 133.50) do not meet state pH standards. These are two sites where additional continuous pH monitoring would be valuable to formally assess the status.

Figure 25. Upper Deschutes River Grab pH 2007 – 2008

Nov‐08 Deschutes River; Grab pH 2007 ‐ 2008 Oct‐08 10.0 9.5 Sep‐08

9.0 Aug‐08 8.5 Jul‐08 8.0 Jun‐08 (SU)

7.5

pH 7.0 Oct‐07

6.5 Sep‐07 6.0 Aug‐07 5.5 5.0 Jul‐07 75 . Jun‐07 ODEQ UDWC UDWC

166 75

DR DR 168.00 DR 160.25 DR 163.25 DR 181.50 DR 169.00 Criteria high DR 165.75 DR 164.75 DR 172.00 DR 123.00 DR 167.25 DR 160.00 DR 191.75 (8.5 SU)

DR 217.25 ODEQ Criteria low DR 133.50 DR 217.25 City of Bend Area DR 133.50 (6.5 SU)

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4.4 Upper Deschutes River Sedimentation and Turbidity

4.4.1 Background

Because it is very difficult and expensive to directly measure sedimentation, turbidity measurements are often used as an indicator of sediment loading because they are far more cost effective and efficient. Turbidity measures the amount of light able to pass through a sample and is inversely reported as nephelometric turbidity units (NTU). Therefore, with increasing NTU, decreasing light passage and increasing solids are reported. Turbidity cannot distinguish between suspended sediment and other materials suspended in the water sample, and it does not address the sources of sediment or the rates of sediment deposition. However, if turbidity measurements indicate that additional studies are necessary, subsequent substrate studies can establish the effects of sediment deposition via embeddedness of aquatic habitats and the ability of a waterway to transport the sediment loads.

A waterway composed of a range of fine sediments to large boulders provides the habitat for many aquatic organisms. Sediments are naturally produced by the erosion of rock and soil particles into a waterway. A healthy waterway has achieved a balance between the sediment load and sediment transport (sedimentation and erosion) thus providing a range of habitat for different aquatic species. Although all rivers move sediment naturally, a waterway with an increased sediment load or increased sediment deposition may stress aquatic organisms that evolved under a different sediment regime because sediment can smother habitat, interfere with spawning and alter the aquatic vegetation. Fine sediments can carry toxins into the water column and, once in the water column, some compounds can partition directly into aquatic species such as fish and enter the food chain. Other toxins adhere to fine sediments, deposit onto the aquatic substrate, partition into benthic organisms, and make their way into the food chain.

Sediment loading occurs from natural and anthropogenic influences and can contribute to the turbidity of a waterway. 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. When an increase in sediment loads occurs, the waterway may transport the increased load of sediment, altering the amount of dissolved solids, suspended solids, deposited solids (sedimentation). Elevated turbidity levels can indicate a waterway that is transporting sediment while low levels of sedimentation may indicate a region of sediment deposition.

It is unclear how the state of Oregon standard for turbidity applies to the Deschutes River. The standard states, “No more than a ten percent cumulative increase in natural stream turbidities may be allowed, as measured relative to a control point immediately upstream of the turbidity

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causing activity” (ODEQ, 2009). It is very difficult to meaningfully apply this standard because the multiple reservoirs, impoundments, and diversions along the Upper Deschutes River all have the potential to alter turbidity. Therefore, any measure of turbidity relative to the state standard depends entirely upon the reference site used in the evaluation. Because of this limitation turbidity is not evaluated against the state standard in this report. Instead, a statistical evaluation of how turbidity changes as it flows through the impoundments located within the City of Bend UGB is used.

4.4.2 Evaluation

To evaluate if turbidity is changing as the Upper Deschutes River flows through the City of Bend UGB, a statistical analysis was utilized to detect changes in the turbidity that can be attributed to features within the City of Bend UGB including dams and diversions, the major features suspected of impacting turbidity along the Upper Deschutes River. A Student’s t‐test was used to identify if there are significant changes in turbidity and, if so, the direction of these changes; increasing or decreasing turbidity. Steps 1 – 5 below provide a simplified description of the steps in analysis that follows. For a more detailed description of the Student’s t‐test reference the Statistical Methods in Water Resources (Helsel & Hirsch, 1991).

Steps in Student’s t‐test of Hypotheses

1. Calculate daily mean turbidities for each station. 2. Use a probability plot to verify the normal distribution of the daily mean turbidities for each station and remove any outliers at 90%. 3. Create a 95% confidence interval plot around the daily mean turbidities for each station and compare. 4. Perform Student’s t‐test (two sample t‐test) to statistically evaluate differences in the daily mean turbidities for each station. 5. Evaluate hypotheses.

The four hypotheses in Table 6 help evaluate turbidity changes within waterways flowing through the City of Bend UGB according to standard methods for water resources analyses (Helsel & Hirsch, 1991).

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Table 6. Trend Analysis Hypotheses

Null: The mean of the upstream station and downstream daily mean turbidity are equal.

The mean of the upstream station and downstream station daily mean turbidity are Alt1: statistically different.

The mean of the downstream station daily mean turbidity is significantly less than the Alt2: mean of the upstream station; Conditions are less turbid downstream.

The mean of the downstream station daily mean turbidity is significantly more than the Alt3: mean of the upstream station; Conditions are more turbid downstream.

Continuous turbidity is available for the Upper Deschutes River through the City of Bend (Figure 26). These data reveal a very low level of turbidity that is similar to previous studies that indicate the average turbidity in the Upper Deschutes River is 3 NTU (Jones, L., 2003) but there are outliers of greater 2000 NTU. The outliers were compared to flow and precipitation patterns (not shown) and no correlations were noted. It is suspected that the outliers are the result of instrument error (e.g., blockage of the optical turbidity probe).

Although continuous data is available for 2005 through 2008, the analysis presented here focuses on the time period of September 8 – 12, 2007 when three turbidity loggers simultaneously collected data that can be used in statistical analysis of turbidity trends. The daily mean turbidity was calculated for the September 8 – 12, 2007 time period and a probability plot was used to check the data for normality (Figure 27). The distribution around the mean and results of a probability plot demonstrate a normal distribution at 95% confidence for all three stations.

Because the data collected at the three stations are normally distributed around their mean they can be used in the Student’s t‐test to evaluate changes in turbidity between stations. An interval plot of the mean daily turbidity reveals the differences in turbidity between stations (Figure 28). Figure 28 illustrates that turbidity is significantly different between the City of Bend southern UGB (DR 172.00), Drake Park Footbridge (DR 166.75), and downstream of the Tumalo boulder field (DR 160.00) because there is no overlap between the 95% confidence interval plots for each station. A Student’s t‐test identifies that the mean daily turbidity is significantly different between the City of Bend southern UGB (DR 172.00), Drake Park Footbridge (DR 166.75), and downstream of the Tumalo boulder field (DR 160.00). Therefore, hypothesis 2 is accepted, suggesting that there is a downstream‐trending decrease in turbidity. This result is

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consistent with the assumption that the impoundments in the City of Bend serve to slow water velocities, thus settling material from the water column and reducing turbidity.

Figure 26. Upper Deschutes River Turbidity Values 2005 ‐ 2008

DR 172.00 DR 166.75 DR 164.75 DR 160.00 2500

2000

1500 (NTU)

1000 Turbidity

500

05 06 07 08 09 ‐ ‐ ‐ ‐ ‐ 12, 2007 January January January January January ‐ September 8

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Figure 27. Probability Plot of Upper Deschutes River Turbidity Values

Probability Plot of Deschutes River Turbdity Normal ‐ 95% CI

99 Variable DR 172.00 95 DR 166.75 DR 160.00 90 Mean StDev N P 80 2.229 0.03821 5 0.835 70 2.071 0.01260 5 0.761 60 1.525 0.01906 5 0.049 50 40 Percent 30 20

1 1.50 1.75 2.00 2.25 2.50 Data

Station ID Description P‐Value α‐value Result Distribution

DR 172.00 City of Bend Southern UGB 0.84 0.05 P > α Normal DR 166.75 Drake Park footbridge 0.76 0.05 P > α Normal DR 160.00 Downstream of Tumalo Creek 0.05 0.05 P > α Normal

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Figure 28. Confidence Interval Plot of Upper Deschutes River Mean Turbidity Values

Interval Plot of Mean Turbidity 95% CI for the Mean

2.6

2.4

(NTU) 2.2

2.0 Turbidity

1.8 Mean

1.6 Daily

1.4

1.2 DR 172.00 DR 166.75 DR 160.00

Station ID Description 5% Mean 95% SD N

DR 172.00 City of Bend Southern UGB 2.2 2.2 2.3 0.04 5 DR 166.75 Drake Park footbridge 2 2.1 2.1 0.01 5 DR 160.00 Downstream of Tumalo Creek 1.5 1.5 1.6 0.02 5

Station ID P‐Value α‐value Result DF T‐value Tα Result

DR 172.00 Reject Null Accept 0.01 0.05 4 5.42 2.13 DR 166.75 Hypothesis Alternative 2

DR 166.76 Reject Null Accept 0.00 0.05 5 60 2.02 DR 160.00 Hypothesis Alternative 2

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4.5 Summary of Results

Tables 7 and 8 present consolidated summaries of the results discussed in Sections 4.1 through 4.4 using the following terminology:

• Standards met: Data presented in this report met the state standards. • Not consistent with 303(d) listing: Standard met: Data presented in this report met the state standards. This contradicts the existing 303(d) list and suggests that de‐listing may be warranted. • Not consistent with 303(d) list; Standard not met: Data presented in this report do not meet state standards, suggesting that a new 303(d) listing may be warranted for this reach. This result contradicts the existing 303(d) list. • Consistent with 303(d) listing; Standard not met: Data presented in this report do not meet state standards. This result is consistent with the existing 303(d) list. • Insufficient data for evaluation: There were not enough data to formally evaluate this parameter with respect to state standards. • Standard not applicable to this reach: The standard does not apply to this reach.

Table 7. Tumalo Creek Ambient Water Quality Status Summary 2007 / 2008

Parameter Temperature Dissolved Oxygen pH Chl‐a Sed./Turb.

Salmon and Bull Trout Trout Salmon and Salmon and Beneficial Spawning Multiple Multiple Multiple Multiple Rearing Trout Non‐ Trout Use Criteria and Uses Uses Uses Uses and Spawning Spawning Rearing Migration Fall / Year August 15 – January 1 – Spring / Season Year Round Winter/ Summer Summer June 15 Summer Round 15‐May Spring ODEQ Reach 11.0 mg/L 8.0 mg/L @ >10% NTU 18 °C 12 °C 6.5 ‐ 8.5 SU 6.5 ‐ 8.5 SU 0.015 mg/L River Mile @ 90% Sat 95% Sat increase

Not consistent Insufficient Insufficient Insufficient Insufficient Insufficient Standard with 303(d) Standard 12.5 – 20.0 data for data for data for data for data for met list; met evaluation evaluation evaluation evaluation evaluation Standard not met

Consistent Standard with 303(d) not Insufficient Insufficient Insufficient Insufficient Insufficient Standard 0.00 – 12.5 listing; applicable data for data for data for data for data for met Standard to this evaluation evaluation evaluation evaluation evaluation not met reach

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Table 8. Upper Deschutes River Ambient Water Quality Status Summary 2007 / 2008

Parameter Temperature Dissolved Oxygen pH Chl‐a Sed.& Turb. Salmon Bull Trout and Trout Beneficial Spawning Non‐ Multiple Multiple Multiple Multiple Rearing Spawning Use and Spawning Uses Uses Uses Uses and Rearing Migration Fall / Year August 15 Year Jan 1 ‐ Spring / Season Winter/ Summer Summer Round – June 15 Round May 15 Summer Spring ODEQ 8.0 mg/L 11.0 mg/L 6.5 ‐ 8.5 6.5 ‐ 8.5 0.015 >10% NTU Reach 18 °C 12 °C @ 95% Sat @ 90% Sat SU SU mg/L increase River Mile Consistent Standard with not Insufficient Insufficient Insufficient Insufficient Insufficient Insufficient 223.3 to 303(d) applicable data for data for data for data for data for data for 244.8 listing; to this evaluation evaluation evaluation evaluation evaluation evaluation Standard reach not met Not Consistent Standard consistent with not Insufficient Insufficient Insufficient Insufficient with Insufficient 189.5 to 303(d) applicable data for data for data for data for 303(d) data for 220.0 listing; to this evaluation evaluation evaluation evaluation listing: evaluation Standard reach Standard not met met Not Not Consistent Not Standard consistent consistent with consistent not with Insufficient with 168.2 to 303(d) with Standard Turbidity applicable 303(d) data for 303(d) 189.4 listing; 303(d) list; met decreasing to this listing: evaluation listing: Standard Standard reach Standard Standard not met not met met met Consistent Consistent Standard with with not Insufficient Turbidity 162.6 to 303(d) Standard Standard 303(d) Standard applicable data for decreasing 168.2 listing; met met listing; met to this evaluation Standard Standard reach not met not met Not Consistent Consistent consistent Consistent Standard with with with with not Turbidity 126.4 to 303(d) Standard 303(d) Section 303(d) Standard applicable decreasing 162.7 listing; met listing; 303(d) listing; met to this Standard Standard Listing: Standard reach not met not met Standard not met Met Note: The City of Bend UGB extends from approximately river mile 172.00 to 163.25 on the Deschutes River.

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5.0 Results: Nutrients, Other Compounds and Biological Indicators

5.1 Nutrients

Table 9 provides a summary of the status of Upper Deschutes River and Tumalo Creek nutrients including nitrogen and phosphorous. The following sections describe each nutrient.

The Upper Deschutes and Little Deschutes Subbasins are nitrogen limited and naturally high in phosphorus due to the influence of volcanic soils (Jones, L., 2003). It is often difficult to detect nitrogen based nutrients in nitrogen limited systems because available nutrients are rapidly utilized by primary producers. Therefore, if nitrogen is detected in a nitrogen limited river system, it should be noted as a result worth investigating.

5.1.1 Nitrogen

Total Nitrogen (TN) is the primary indicator of nitrogen levels in a waterway and is the sum of nitrate‐N, nitrite‐N, and Total Kjeldahl Nitrogen (TKN). TN cannot be evaluated directly in this report because the monitoring presented in this report did not include instances when measurable amounts of nitrate, nitrite, and TKN occurred simultaneously. Therefore, individual nitrate, nitrite, and TKN measurements are summarized and compared to the TN guidance provided by the EPA in Table 9 (EPA, 2000).2,3 It can be assumed that if an individual constituent of TN is above the TN guidance, then the TN guidance is exceeded.

Some of the values reported in Table 9 exceed federal guidance values. These locations are predominately between Wickiup Reservoir and North Canal Dam. While the specific sources cannot be teased apart in this report, inputs could be the result of a combination of upstream [e.g., Wickiup Reservoir, upstream sediment inputs, and inputs from the La Pine Aquifer groundwater (Jones, L., 2003) (Hinkle, Morgan, Orzol, & Polette, 2007)] and local sources [e.g., stormwater inputs, runoff from fertilized lawns, and local sediment inputs (City of Bend, 2008)]. Because there are known nutrient sources from Wickiup Reservoir, south Deschutes County,

2 Note that EPA guidance values are the EPA’s recommended starting points for states and tribes to begin the process of setting nutrient standards. Therefore, guidance values are presented here for context and should not be considered standards or regulations. 3 Per EPA (2000), most of the study area is located within EPA’s Ecoregion II while some of the monitoring sites are located within Ecoregion III. Because the EPA guidance values are included in this report for context (but not as rigid standards) guidance values for both Ecoregion II and III are included in this report to allow comparison. Monitoring stations located upstream of river mile 164.75 are located within Ecoregion II whereas stations located at or below river mile 164.75 are within Ecoregion III.

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Table 9. Upper Deschutes River and Tumalo Creek Nutrients Status Summary

Exceedences EPA Max Top Five Stations Date Value5 /Observations Guidance4 DR 166.75 Deschutes River Drake Park Footbridge 9/20/2004 0.9 TKN‐N DR 164.75 Deschutes River u/s Riverhouse Hotel 8/16/2004 0.54 TN (II) = 0.12 mg/L 32/163 0.87 DR 164.75 Deschutes River u/s Riverhouse Hotel 6/22/2004 0.47 TN (III) = 0.38 DR 173.00 Deschutes River USFS Meadow Camp 6/21/2004 0.43 DR 167.50 Deschutes River Colorado St. Footbridge 6/21/2004 0.38 DR 168.00 Deschutes River Columbia St. Bridge 8/30/2006 0.45 Nitrite as N DR 167.25 Deschutes River Columbia Park Footbridge 9/13/2006 0.04 TN (II) = 0.12 mg/L 1/449 0.45 DR 168.00 Deschutes River Columbia St. Bridge 10/21/2008 0.04 TN (III) = 0.38 DR 167.25 Deschutes River Columbia Park Footbridge 10/24/2006 0.02 DR 164.75 Deschutes River u/s Riverhouse Hotel 5/23/2006 0.02 DR 169.00 Deschutes River u/s end Mill Log Pond 10/23/2007 0.32 Nitrate as N DR 168.00 Deschutes River Columbia St. Bridge 10/23/2007 0.32 TN (II) = 0.12 mg/L 38/459 0.32 DR 164.75 Deschutes River u/s Riverhouse Hotel 10/23/2007 0.32 TN (III) = 0.38 DR 172.00 Deschutes River Southern UGB 10/24/2007 0.32 DR 166.75 Deschutes River Drake Park Footbridge 10/24/2007 0.32 DR 217.25 Deschutes River Pringle Falls Experimental Station 1/10/2006 0.19

Nutrients Nitrate/Nitrite N DR 217.25 Deschutes River Pringle Falls Experimental Station 3/11/2008 0.05 TN (II) = 0.12 mg/L 1/81 0.19 DR 217.25 Deschutes River Pringle Falls Experimental Station 1/27/2004 0.03 TN (III) = 0.38 DR 133.50 Deschutes River Lower Bridge 1/9/2006 0.03 DR 191.75 Deschutes River Harper Bridge 9/19/2006 0.03 DR 169.00 Deschutes River u/s end Mill Log Pond 10/23/2007 0.30 Orthophosphate as P DR 166.75 Deschutes River Drake Park Footbridge 10/24/2007 0.30 TP (II) = 0.01 mg/L 24/501 0.30 DR 168.00 Deschutes River Columbia St. Bridge 10/23/2007 0.29 TP (III) = 0.02 DR 165.75 Deschutes River First St. Rapids 10/23/2007 0.29 DR 172.00 Deschutes River Southern UGB 10/24/2007 0.29 DR 159.50 Deschutes River Tumalo Bridge 8/18/2004 0.40 Phosphorus‐Total DR 168.00 Deschutes River Columbia St. Bridge 8/17/2004 0.34 TP (II) = 0.01 mg/L 354/389 0.40 DR 163.25 Deschutes River Firerock Footbridge 8/16/2004 0.33 TP (III) = 0.02 DR 166.75 Deschutes River Drake Park Footbridge 5/17/2005 0.33 DR 166.00 Deschutes River u/s Portland Ave. Bridge 8/16/2004 0.32

4 Per EPA (2000), most of the study area is located within EPA’s Ecoregion II while some of the monitoring sites are located within Ecoregion III. Because the EPA guidance values are included in this report for context (but not as rigid standards or regulations) guidance values for both Ecoregion II and III are included in this report to allow comparison. Monitoring stations located upstream of river mile 164.75 are located within Ecoregion II whereas stations located at or below river mile 164.75 are within Ecoregion III. 5 Total phosphorus guidance values are compared to orthophosphate results for comparison only. Orthophosphate is not equivalent to total phosphorus and constitutes only a portion of a samples total phosphorus value. Guidance values for total phosphorus are equal to or lower than typical method reporting limits for both total phosphorus (MRL=0.02 mg/L) and orthophosphate (MRL=0.1 mg/L). City of Bend Ambient Water Quality Monitoring Report 56

and stormwater runoff in Sunriver, Bend and other areas, additional nutrient monitoring should be conducted to better understand potential sources and implications.

5.1.2 Phosphorus

Total phosphorus and orthophosphate are likely to be naturally high in the Deschutes River system because of the underlying geology. Therefore, the values reported here are most likely the result of natural conditions. The TP guidance provided by the EPA is used to evaluate TP concentrations in Table 9 (EPA, 2000).6,7

5.2 Other Compounds

Other compounds discussed in this section include ammonia, chloride and fluoride, and sulfate. Source of these compounds are typically anthropogenic. Table 10 provides a summary of the Upper Deschutes River and Tumalo Creek results, all of which are within guidelines.

5.2.1 Ammonia

Ammonia has been reported toxic to fresh water organisms at concentrations ranging from 0.53 to 22.8 mg/L (EPA, 1999). Toxic levels are both pH and temperature dependent and, according to Oregon Administrative Rules (OAR, 2010), can be calculated on a per sample basis using the EPA Ambient Water Quality Criteria for Ammonia (EPA, 1999). Concentrations reported here are well below guidelines.

5.2.2 Chloride

Freshwater has a chloride concentration from 1‐250 mg/L. A chloride range of 45‐155 mg/L for a river is considered normal. The state of Oregon has a chloride standard not to exceed 860 mg/L (OAR, 2010). Concentrations reported here are well below guidelines.

6 Note that EPA guidance values are the EPA’s recommended starting points for states and tribes to begin the process of setting nutrient standards. Therefore, guidance values are presented here for context and should not be considered standards or regulations. 7 Per EPA (2000), most of the study area is located within EPA’s Ecoregion II while some of the monitoring sites are located within Ecoregion III. Because the EPA guidance values are included in this report for context (but not as rigid standards) guidance values for both Ecoregion II and III are included in this report to allow comparison. Monitoring stations located upstream of river mile 164.75 are located within Ecoregion II whereas stations located at or below river mile 164.75 are within Ecoregion III.

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Table 10. Upper Deschutes River and Tumalo Creek Other Compounds

Exceedences Standard or Max Top Five Stations Date Value /Observations Guidance

DR 163.25 Deschutes River Firerock Footbridge 5/17/2005 0.11 Ammonia as N DR 217.30 Deschutes River Pringle Falls Experimental Station 11/17/2004 0.10 mg/L 0/492 0.538 0.11 TC 007.50 Tumalo Creek u/s Road 4606 5/23/2006 0.10

DR 160.00 Deschutes River d/s boulder field 5/24/2006 0.09 DR 166.75 Deschutes River Drake Park Footbridge 6/16/2005 0.08 DR 159.50 Deschutes River Tumalo Bridge 6/23/2004 3.8

Chloride TC 000.25 Tumalo Creek Mouth 6/23/2004 2.3 mg/L 0/449 860.09 3.8 DR 163.25 Deschutes River Firerock Footbridge 3/15/2005 1.8 Concern

DR 168.00 Deschutes River Columbia St. Bridge 3/16/2005 1.8 DR 160.25 Deschutes River u/s Tumalo Creek 3/15/2005 1.8 Potential DR 168.00 Deschutes River Columbia St. Bridge 10/23/2007 0.39 of

Fluoride DR 169.00 Deschutes River u/s end Mill Log Pond 10/23/2007 0.39 mg/L 0/276 0.5010 0.39 DR 160.00 Deschutes River d/s boulder field 10/24/2007 0.38

Compounds DR 165.75 Deschutes River First St. Rapids 10/23/2007 0.38 DR 160.25 Deschutes River u/s Tumalo Creek 10/24/2007 0.38 DR 167.25 Deschutes River Columbia Park Footbridge 7/11/2007 5.9 Sulfate as SO4 DR 167.25 Deschutes River Columbia Park Footbridge 5/8/2007 3.0 10011 mg/L 0/449 5.9 DR 166.75 Deschutes River Drake Park Footbridge 10/24/2007 2.1 25012 DR 165.75 Deschutes River First St. Rapids 4/5/2006 1.9 DR 172.00 Deschutes River Southern UGB 8/7/2007 1.7

8 Guidance (EPA, 1999) 9 Standard (ODEQ, 2009) 10 Guidance (Carmago, 2003) 11 Standard (OAR, 2010) 12 Guidance (EPA, 2010)

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5.2.3 Fluoride

Fluoride in water derives mainly from dissolution of natural minerals in the rocks and soils and higher concentrations occur in areas with volcanic influence. In freshwaters, fluoride concentrations as low as 0.5 mg F‐/L can adversely affect invertebrates and fishes (Carmago, 2003). The state of Oregon does not have a fluoride set standard to protect aquatic life (OAR, 2010), therefore the Carmago (2003) estimate of fluoride concentrations that can adversely affect aquatic life is used. Concentrations reported here are well below guidelines.

5.2.4 Sulfate

Sulfate occurs in freshwater at concentrations that range from a few to several thousand milligrams per liter (NIST, 1998). There is no state of Oregon standard or federal guidance for sulfate in freshwaters. However, the state guidance for TDS, of which sulfate is a major constituent, is 100 mg/L (OAR, 2010) and the federal drinking water standard for sulfate is 250 mg/L (EPA, 2010). Both are provided in Table 10. Sulfate concentrations reported here are well below these guidelines.

5.3 Biological Indicators

Biological indicators discussed here include Escherichia coli and indicators of primary productivity (chlorophyll‐a and pheophytin‐a). Table 11 provides a summary of the biological indicator status for the Upper Deschutes River and Tumalo Creek. Each indicator is described in the following sections.

5.3.1 Escherichia coli

The state of Oregon has set Escherichia coli concentrations at 406 MPN/100ml to protect recreational waters (OAR, 2010). Escherichia coli exceeded state standards on Tumalo Creek at the Mouth (TC 000.25) for single grab samples on two occasions, yet E. coli levels are not consistently elevated and do not justify a 303(d) listing. Escherichia coli do not exceed state standards on the Upper Deschutes River. However, if there is a source of E. coli on Tumalo Creek, it is possible for this to affect downstream recreational uses at Tumalo State Park on the Deschutes River. Therefore, additional monitoring should be conducted to better understand whether the values on Tumalo Creek are simply anomalous or indicative of a potential concern.

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Table 11. Upper Deschutes River and Tumalo Creek Biological Status Summary

Exceedences Standard or Max Top Five Stations Date Value /Observations Guidance

TC 000.25 Tumalo Creek Mouth 4/22/2008 2420 E. coli DR 133.50 Deschutes River Lower Bridge 6/30/2008 613 MPN/100mL 2/513 40613 2420 DR 160.25 Deschutes River u/s Tumalo Creek 8/3/2005 345

DR 160.00 Deschutes River d/s boulder field 4/22/2008 308 DR 163.25 Deschutes River Firerock Footbridge 4/5/2006 249 DR 217.25 Deschutes River Pringle Falls Experimental Station 7/28/2004 11.00 Chlorophyll a DR 217.25 Deschutes River Pringle Falls Experimental Station 7/1/2008 11.00 15 μg/L14 μg/L 0/103 11.00 Deschutes River Pringle Falls Experimental Station 9/13/2005 11.00 1.08 μg/L15 DR 217.25 Biological DR 217.25 Deschutes River Pringle Falls Experimental Station 7/20/2005 10.40 DR 191.75 Deschutes River Harper Bridge 9/13/2005 9.50 DR 217.25 Deschutes River Pringle Falls Experimental Station 7/20/2005 3.70 Pheophytin a DR 133.50 Deschutes River Lower Bridge 5/16/2005 3.10 μg/L 103 NA 3.70 DR 163.25 Deschutes River Firerock Footbridge 8/16/2004 3.10

DR 217.25 Deschutes River Pringle Falls Experimental Station 9/5/2007 3.00 DR 133.50 Deschutes River Lower Bridge 9/4/2007 2.70

13 Standard (OAR, 2010) 14 Standard (OAR, 2010) 15 Guidance (EPA, 2000)

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5.3.2 Primary Productivity (Chlorophyll‐a and Pheophytin‐a)

The primary productivity in a waterway refers to the plants that utilize photosynthesis to convert photons (sunlight energy) into consumer usable ATP (chemical energy). Primary producers include aquatic plants, phytoplankton, and periphyton, while consumers include aquatic macroinvertebrates, fish, and wildlife. Due to the ability of primary producers to convert sunlight energy into a usable product (chemical energy), primary producers form the basis of the aquatic food chain. Primary producers utilize various pigments to perform this service, and all primary producers use chlorophyll‐a. Therefore, from a water quality perspective, chlorophyll a is a good indicator of suspended (sestonic) primary growth and abundance. It is not, however, an indicator to the abundance of benthic primary producers such as macrophytes that take root in deposited sediments or attach to rocks. An important degradation product of chlorophyll‐a that interferes with its measurement is pheophytin‐a. Pheophytin‐a can interfere with the quantification of chlorophyll‐a and is used to determine a more accurate measure of chlorophyll‐a. Elevated levels of chlorophyll‐a indicate increases in primary production within a waterway.

The state of Oregon standard that applies to chlorophyll‐a is set to measure nuisance phytoplankton growth and states that chlorophyll‐a concentrations should not exceed 0.015 mg/L (15 μg/L) (OAR, 2010). The chlorophyll‐a guidance of 1.08 μ/L provided by the EPA (EPA, 2000) is based upon regional concentrations. Both the state standard and regional guidance are used to evaluate chlorophyll‐a concentrations in Table 11.

The federal guidance for chlorophyll‐a is approximately 14 times more strict than the state criteria. This is likely related to the state criteria being focused on nuisance conditions (e.g., excessive phytoplankton growth that can affect recreational uses) rather than using chlorophyll‐a as an indicator of primary productivity. The concentrations reported here meet state criteria but exceed the EPA guidance, suggesting that there is a need to better understand the significance of the federal and state criteria, whether these results are indicative of increased primary productivity, natural background conditions in the Deschutes River and other factors that may affect the interpretation of these data.

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6.0 Discussion

The following summarizes the key results from this report:

Summary of Water Quality Status

Data presented in this report suggest that changes to the existing 303(d) list may be warranted. Specifically, there are some data suggesting new listings and other data that suggest listings may not be warranted (see Tables 7 and 8). However, it is important to note that ODEQ has sole responsibility for evaluating available data, preparing the 303(d) list and modifying the 303(d) list over time so these results will not automatically trigger any action by ODEQ. When ODEQ conducts this evaluation in the future, there are many factors that may affect whether changes to the 303(d) list are made.

Portions of the Deschutes River are currently listed on the 303(d) list for not meeting state standards for temperature, dissolved oxygen, pH, chlorophyll‐a and sedimentation/turbidity. The following reach may qualify for being added to the 303(d) list for the Deschutes River:

• pH (Fall/Winter/Spring): River mile 168.2 to 189.4.

Data presented in this report suggest that the following Deschutes River reaches meet water quality standards, contradicting the existing 303(d) list:

• Chloropyll‐a: River mile 168.2 to 189.4, and 189.5 to 220.0; • Dissolved oxygen (non‐spawning): River mile 168.2 to 189.4; and • pH (Fall/Winter/Spring): River mile 126.4 to 162.7.

Portions of Tumalo Creek are listed on the 303(d) list for not meeting state standards for temperature. Data presented in this report suggest that the following may qualify for being added to the 303(d) list for Tumalo Creek:

• Temperature (Bull Trout Spawning and Rearing): River mile 12.5 to 20.0.

Results for ammonia, chloride, fluoride and sulfate are all within the identified guidelines. Nitrogen and phosphorous values exceed the federal guidance. Results for E. Coli includes values that exceed the standard or guidance. The E. coli results in Tumalo Creek should be investigated further to determine if they are indicative of a larger problem or simply anomalous data. The chlorophyll‐a concentrations reported here meet state criteria but exceed the EPA guidance, suggesting that there is a need to further evaluate the importance of this result.

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Potential Factors Influencing Water Quality

Although the monitoring conducted for this report was not focused on testing cause‐and‐effect relationships, there are some general observations that can be made regarding potential influences on the observed water quality. These observations should be considered as background information or hypotheses that may be useful for future studies.

As the Deschutes River flows cross the City of Bend’s southern UGB, water temperatures have already reached the state temperature standard of 18 °C / 64 °F. Therefore, even though water temperatures increase in the impoundments within the City of Bend, the temperatures are already near or above state standards before the flows reach the City of Bend. The temperatures observed in the Deschutes River upstream of the City of Bend are likely the result of numerous factors, including the temperature of the water that flows from Wickiup Reservoir as well as the temperature of various tributaries (i.e., Fall River, Little Deschutes River, Spring River, and groundwater springs downstream of Spring River) and the naturally occurring downstream warming that happens in most river systems.

As the water flows through the four impoundments located within the City of Bend, the rate of temperature warming increases. These impoundments also serve to slow the river and promote sediment deposition. These conditions – warm, slow moving water with fine sediment – provide an ideal environment for the growth of algae and other aquatic vegetation, particularly if there are nutrient inputs into the river. As this vegetation grows, dies and is decomposed, these processes can reduce the concentrations of dissolved oxygen and alter pH. Given that the Deschutes River is 303(d) listed for temperature, pH and dissolved oxygen, it would be valuable to understand precisely how the dynamics of sediment deposition, vegetative growth and decomposition potentially affect these parameters. However, because the dams that form these impoundments are not owned, managed, operated or approved by the City of Bend, the City’s role in this work would likely be via partnerships with the operators of the dams.

The results presented in this report coupled with the existing 303(d) listing for chlorophyll‐a indicate that there is a need to better understand primary productivity in the Deschutes River. While the drivers of primary productivity have not been specifically identified, they may include nutrients from natural sources, Wickiup Reservoir, south Deschutes County and/or stormwater runoff within the study area. However, primary productivity is likely to affect dissolved oxygen and pH (as described above) and, therefore, be an important consideration in understanding the drivers behind the 303(d) listings. Given that the Deschutes River is 303(d) listed for dissolved oxygen, pH, chlorophyll‐a and temperature, all of which may be interrelated to each other and affected by nutrient cycling, it would be very valuable to further study the nutrient dynamics in the Deschutes River to better understand how the system is functioning.

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Understanding nutrient cycling in the river will also help inform analyses of how nutrient inputs from upstream or local sources do or do not affect 303(d) listed parameters.

Most of the major diversions on the Deschutes River are located within the City of Bend. Because these diversions reduce streamflow during the summer months, resulting in increased water temperature, they are important influences on water quality. However, much like the impoundments, these diversions are not owned, managed or operated by the City. Therefore, the City’s role in addressing the water quality impacts of reduced streamflow on the Deschutes River is one of partner and collaborator with the irrigation districts, Deschutes River Conservancy and other partners.

Another local influence on the water quality through the City of Bend is Tumalo Creek. As a tributary to the Deschutes River near the northern edge of Bend, Tumalo Creek can be either a warming or cooling influence depending upon the amount of flow in Tumalo Creek (UDWC, 2006b). Therefore, efforts to reduce water temperature in the middle Deschutes should consider streamflow in Tumalo Creek as one of the key drivers.

7.0 Recommendations for Further Study

Based on the information presented in this report and others, we recommend the following additional studies and evaluations:

1. Evaluate cause and effect relationships. The monitoring presented in this report was focused on assessing the status and, in some cases, trends in water quality within the study area. This monitoring was not intended to assess cause and effect relationships between observed water quality conditions and potential influences. Therefore, there are many potential questions for additional study that would focus on identifying cause and effect relationships, including: o What are the key drivers, such as sedimentation, temperature and/or nutrient inputs, that may influence algal growth in the Deschutes River (e.g., Mirror Pond and other impoundments)? What is the relative importance of each driver? What are the primary sources and/or causes of each driver? How would potential future management approaches in Mirror Pond affect each driver? o How does the algal growth in the Deschutes River influence pH, dissolved oxygen and other parameters in the Deschutes River?

2. Support continued monitoring in the Deschutes River and Tumalo Creek to allow continued tracking of water quality conditions. Specific focus should include: a) Continued monitoring of 303(d) listed parameters at all of the monitoring sites within the study area.

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b) Investigation of the high E. coli results in Tumalo Creek by conducting additional monitoring. c) Continued and/or expanded continuous multi‐parameter monitoring on the Deschutes River at stations 181.50, 172.00, 166.75 and 133.50 to provide expanded context for water quality conditions within the City of Bend. In particular, the upstream stations provide important information on the water quality of the Deschutes River before it reaches the City of Bend. This should include early season monitoring (starting April 1) to develop better data. These data will also help provide more information about the dissolved oxygen conditions discussed in this report.

3. Further examine primary productivity in the Deschutes River. This is an important area of study because there are several indications of potentially elevated primary productivity that could be indicative of elevated nutrient inputs: o Portions of the Deschutes River are currently 303(d) listed for chlorophyll‐a, indicating that there may be elevated levels of primary productivity. Elevated levels of primary productivity would likely be linked to elevated nutrient levels. o High levels of algal growth can be observed in many locations throughout the Deschutes River, potentially indicating elevated primary productivity. o Because the Deschutes River is a nitrogen limited system and there are known sources of nutrient inputs (e.g., groundwater in south Deschutes County, releases from Wickiup reservoir and stormwater runoff), it is likely that there is elevated primary productivity. Increases in primary productivity can result in changes in pH and dissolved oxygen, which are important parameters on the 303(d) list. Additional study should focus on more comprehensive productivity and nutrient monitoring to better understand baseline conditions throughout the entire Upper Deschutes River and Little Deschutes River watersheds, an assessment of known and potential local and regional nutrient sources, and modeling of potential future conditions in the Deschutes River under a variety of nutrient input scenarios.

4. Support efforts by the U.S. Forest Service, Oregon Water Resources Department, Deschutes River Conservancy, Irrigation Districts and others to address erosion and sediment transport in the Deschutes River upstream of the City of Bend. This may include, but not necessarily be limited to, winter flow restoration, irrigation water conservation, bank stabilization and other types of projects that address both root causes (i.e., streamflow alternation) as well as symptoms (i.e., bank instability). Sediment reductions in Bend will benefit water quality and help address other key issues, such as the management of Mirror Pond.

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8.0 Bibliography

Breuner, N. (2003). Temperatures of the Upper Deschutes and Little Deschtues Subbasins. Bend, Oregon: Upper Deschutes Watershed Council.

Carmago, J. (2003). Fluoride toxicity to aquatic organisms: a review. Chemosphere vol. 50, p. 252 ‐ 254.

City of Bend. (2004). Quality Assurance Project Plan; City of Bend Ambient Water Quality Monitoring. Bend: Upper Deschutes Watershed Council.

City of Bend. (2008). 2007‐2008 Annual Report Stormwater NPDES Permit No. 102901. City of Bend: Public Works Department, Stormwater Utility Division.

EPA. (1999). 1999 Update of Ambient Water Quality Criteria for Ammonia. Washington, D.C.: Envrionmental Protection Agency, Office of Water, EPA 822‐R‐99‐014.

EPA. (2000). Ambient Water Quality Criteria Recommendations; Information Supporting the Development of State and Tribal Nutrient Criteria. Rivers and Streams in Nutrient Ecoregion II. Washington, D.C.: Environmental Protection Agency EPA 822‐B‐00‐015.

EPA. (2010). Drinking Water Contaminants, Environmental Protection Agency. http://www.epa.gov/safewater/contaminants/index.html.

Helsel, D. R., & Hirsch, R. M. (1991). Statistical Methods in Water REsources, Techniques of Water Resources Investigations of the United States Geological Survey, Book 4, Hydrologic Analysis and Interpretation Chapter A3. United States Geological Survey.

Hinkle, S., Morgan, D., Orzol, L., & Polette, D. (2007). Ground Water Redox Zonation near La Pine, Oregon: Relation to River Positino within the Aquifer‐Riparian Zone Continuum. Prepared in cooperation with Deschutes County: U.S. Department of the Interior, U.S. Geological Survey Scientific Investigations Report 2007‐5239.

Jones, L. (2003). Characterization of Select Water Quality Parameters within the Upper Deschutes and Little Deschutes Subbasins. Bend, Oregon: Upper Deschutes Watershed Council.

Jones, L. (2007). City of Bend Water Quality Monitoring 2005 ‐ 2006. Bend: Upper Deschutes Watershed Council.

Jones, L. (2008). City of Bend Water Quality data Summary 2005 ‐ 2007. Bend: Upper Deschutes Watershed Council.

Lamb, B. (2009, September 28). ODEQ Basin Coordinator. (L. Jones, Interviewer)

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NIST. (1998). Standard Methods for the Examination of Water and Wastewater 20th Edition. National Institute of Science and Technology.

OAR. (2010). Water Quality Standards: Beneficial Uses, Policies, and Criteria for Oregon. Oregon Administrative Rules, Chapter 340, Division 041. Retrieved from http://www.deq.state.or.us/regulations/rules.htm.

ODEQ. (2006). Assessment Methodology for Oregon's 2004/2006 Integrated Report on Water Quality Status. Portland, Oregon: Oregon Department of Environmental Quality.

ODEQ. (2004). Oregon's 2004 Water Quality Assessment. Water Quality Division. Portland, Oregon: Oregon Department of Environmental Quality.

ODEQ. (1995). State of Oregon 1992 ‐ 1994 Water Quality Standards Review. Portland, Oregon: Oregon Department of Environmental Quality.

ODEQ. (2009). Water Quality Standards: Beneficial Uses, Policies, and Criteria for Oregon. Oregon Administrative Rules, Chapter 340, Division 041. Portland, Oregon: Oregon Department of Environmental Quality.

UDWC. (2002). Sampling and Analysis Plan; Upper Deschutes Basin Stream Temperature Monitoring Plan. Bend: Upper Deschutes Watershed Council.

UDWC. (2006a). Quality Assurance Project Plan; Water Quality Monitoring Program. Bend: Upper Deschutes Watershed Council.

UDWC. (2006b). Deschutes River Temperature Summary 2004‐2006. Bend: Upper Deschutes Watershed Council.

UDWC. (2008). Quality Assurance Project Plan; Water Quality Monitoring Program. Bend: Upper Deschutes Watershed Council.

UDWC. (2009). Water Quality Monitoring Program Standard Operating Procedures. Bend: Upper Deschutes Watershed Council.

USBR. (2003). Biological Assessment on the Continued Operation and Maintenance of the Deschutes River Basin Projects and Effects on Essential Fish Habitat under the Magnuson‐ Stevens Act, Appendix B Water Quality Report. Pacific Northwest Regional Office, Portland: U.S. Department of Interior, Bureau of Reclamation.

USDI. (2006). Dams, Projects, and Powerplants. United States Department of Inerior Bureau of Reclamation.

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USFS. (1998). Bend Watershed Analysis, Deschutes National Forest. Bend, Oregon: U.S. Forest Service, Bend Fort Rock Ranger District.

USGS. (2008). Hydrologic Unit Map. United States Geological Survey.

Yake, K. (2003). Upper Deschutes Subbasin Assessment. Bend, Oregon: Upper Deschutes Watershed Council.

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Appendix A: 303(d) Listing Maps

Please see Tables 7 and 8 for additional information about these maps.

City of Bend Ambient Water Quality Monitoring Report Appendix A‐1

Map A‐1. Study Area 303(d) Listed Impaired Waterways

City of Bend Ambient Water Quality Monitoring Report Appendix A‐2

Map A‐2. 303(d) Listed Impaired Temperature

City of Bend Ambient Water Quality Monitoring Report Appendix A‐3

Map A‐3. 303(d) Listed Impaired Dissolved Oxygen

City of Bend Ambient Water Quality Monitoring Report Appendix A‐4

Map A‐4. 303(d) Listed pH

City of Bend Ambient Water Quality Monitoring Report Appendix A‐5

Map A‐5. 303(d) Listed Chlorophyll‐a

City of Bend Ambient Water Quality Monitoring Report Appendix A‐6

Map A‐6. 303(d) Listed Sedimentation and Turbidity

City of Bend Ambient Water Quality Monitoring Report Appendix A‐7

Appendix B: Photos

City of Bend Ambient Water Quality Monitoring Report Appendix B‐1

The Upper Deschutes River Sediment Deposition and Thermal Warming Reach

Photos by L. Jones

The Upper Deschutes River is impounded at four locations through the City of Bend. These impoundments are areas of sediment deposition and increased rates of water warming. A TMDL will be created for the Upper Deschutes River that includes regulation of temperature, dissolved oxygen, pH, chlorophyll‐a, nutrients, and sedimentation.

City of Bend Ambient Water Quality Monitoring Report Appendix B‐2

Upper Deschutes River Downstream of Wickiup Reservoir during High Summer Flows

Photo by L. Jones

The sedimentation within the City of Bend UGB is likely exacerbated by flow management and bank erosion in the Upper Deschutes. The Upper Deschutes River downstream of Wickiup Reservoir is characterized by high summer flows that create steep, eroding banks that are a source of sediment. Sediment travels from the source and is deposited downstream. A TMDL will be created for the Upper Deschutes River that includes regulation of temperature, dissolved oxygen, pH, chlorophyll‐a, nutrients, and sedimentation. This widespread issue of erosion and sedimentation will likely be discussed during the development of the TMDL.

City of Bend Ambient Water Quality Monitoring Report Appendix B‐3

Middle Reach of the Deschutes River Downstream North Canal Dam during Low Summer Flows

Photo by L. Jones

The Middle reach of the Deschutes River downstream of North Canal Dam is characterized by exposed, water‐polished boulders during summer low flows. The low flows are considered the primary driver to water temperature impairment downstream of the North Canal Dam located within the City of Bend UGB. The contribution of Tumalo Creek flow to the Middle reach of the Deschutes River can have a local cooling affect at the City of Bend Northern UGB. The TMDL being developed for Tumalo Creek will address temperature impairment within the creek, likely resulting in changes to water quality in the Middle Deschutes as well.

City of Bend Ambient Water Quality Monitoring Report Appendix B‐4