Annual Water Quality and Benthic Algae Monitoring Results for the Clark Fork River Basin 2014

CLARK FORK RIVER WATER QUALITY MONITORING COMMITTEE

ANNUAL WATER QUALITY AND BENTHIC ALGAE MONITORING RESULTS FOR THE CLARK FORK RIVER BASIN 2014

6/23/2015

Prepared by: Christine Brick, Clark Fork Coalition, P.O. Box 7593, Missoula, MT 59807 Table of Contents

1.0 Introduction ...... 2 2.0 History and Background ...... 2 3.0 Monitoring Program ...... 2 4.0 Data Quality Control ...... 5 5.0 Nutrient Results ...... 6 5.1 Total Phosphorous ...... 6 5.2 Soluble Reactive Phosphorous ...... 6 5.3 Total Nitrogen ...... 7 5.4 Nitrate + Nitrite ...... 7 5.5 Ammonia ...... 8 6.0 Benthic Algae Results ...... 14 7.0 Peak Flow Nutrient Monitoring ...... 16 8.0 References ...... 17

Figures Figure 1: Clark Fork and Pend Oreille River Monitoring Sites.………………………………………………………………….4 Figure 2: Total phosphorous results.……………………………………………………………………………………………………….9 Figure 3: Soluble reactive phosphorous results.….………………………………………………………………………………..10 Figure 4: Total nitrogen results..……………………………………………………………………………………………………………11 Figure 5: Nitrate + nitrite results………………………………………..……………………………...…………………………………12 Figure 6: Ammonia results…………………………………………………………………………………………………………………….13 Figure 7: Benthic algae chlorophyll-a and ash-free dry weight results…………………………………………………..15

Tables Table 1: Monitoring Locations, Rationale, & Sampling Frequency on Clark Fork River and Tributaries……5 Table 2: Estimated Lake Pend Oreille Nutrient Loads from Clark Fork River 2012 to 2014…………………….17

Attachments QA/QC Report for Clark Fork River Monitoring 2014 CFR-BASIN Data Tables HydroSolutions Tech Memo: Estimate of 2014 Nutrient Loading from Clark Fork River into Lake Pend Oreille

1 1.0 INTRODUCTION

This report presents 2014 nutrient and benthic algae monitoring results from the Clark Fork River basin collected by the University of Montana (UM), the City of Missoula, and Avista Corporation (Avista) and overseen by the Clark Fork River Water Quality Monitoring Committee (CFRWQMC). This report also summarizes and presents results of quality assurance and quality control analysis by the Montana Department of Environmental Quality (MDEQ), and annual nutrient loading analysis to Lake Pend Oreille by Avista. The purpose of the report is to present monitoring results and assess the results with respect to compliance with water quality standards.

Further analysis of the annual results from this monitoring program is accomplished on a five-year schedule when the Clark Fork River Water Quality Monitoring Committee contracts a statistical evaluation and trends analysis. The latest trends report covered the period 1998-2012 (HydroSolutions, 2014) and the next trends report will be presented in 2018, adding data through 2017.

2.0 HISTORY AND BACKGROUND

The current monitoring program is a continuation of the Montana portion of program begun through the Tri-State Water Quality Council (TSWQC) in 1998. The TSWQC, a partnership of citizens, businesses, industry, tribes, government, and environmental groups, formed in 1993 to collaboratively address solutions to the problem of excess nutrients and algae identified in the Clark Fork-Pend Oreille Basin Management Plan (EPA, 1993) in Montana, Idaho and Washington. The monitoring committee of the TSWQC began a basin-wide targeted monitoring program in 1998, in part to assess the progress of a 10- year Voluntary Nutrient Reduction Program (VNRP) in Montana. The monitoring program employed a statistically-based sampling design and was intended to support sound, scientifically-based water management decisions. Nutrient and algal targets developed for the VNRP were later adopted as numeric standards in the Clark Fork basin in 2002 – the first numeric standards for nutrients and algae in Montana. Due to shrinking budgets, the TSWQC disbanded in 2012 but Montana DEQ assumed responsibility for monitoring in the Clark Fork basin. Former members of the TSWQC in Montana and Idaho formed the Clark Fork River Water Quality Monitoring Committee (CFRWQMC), comprised of MDEQ, Avista, City of Missoula, UM Watershed Clinic, and Idaho Department of Environmental Quality (IDEQ), to continue and oversee the monitoring effort. The 2013-2017 monitoring program represents the first 5 year monitoring program managed by the CFRWQMC. The Tri-State Water Quality Council managed the previous 5 year monitoring programs from 1998-2002, 2003-2007, and 2008-2012, which provided the basis for a statistical analysis of water quality time trends for the Clark Fork River and Lake Pend Oreille Watershed. The CFRWQMC modified the monitoring plan to be as cost effective as possible while still maintaining continuity for statistical analysis.

3.0 MONITORING PROGRAM

The CFRWQMC monitoring program in Montana maintains two of the original four management goals established by the TSWQC which are to: 1) Control nuisance algae in the Clark Fork River by reducing nutrient concentrations 2) Protect Lake Pend Oreille water quality by maintaining or reducing current rates of nutrient loading from the Clark Fork River To meet these goals in Montana, the CFRWQMC will:

2 1) Evaluate time trends in nutrient concentrations in the mainstem Clark Fork River and selected tributaries; 2) Evaluate time trends for periphyton (algae) standing crops in the Clark Fork River; 3) Monitor summer nutrient and periphyton target levels in the Clark Fork River; 4) Estimate nutrient loading rates to Lake Pend Oreille from the Clark Fork River;

The states of Idaho and Washington carry out additional monitoring and studies to address the remaining TSWQC goals and objectives specific to Lake Pend Oreille and the Pend Oreille River. These are described in the Quality Assurance Project Plan (QAPP) (MDEQ, 2015). Water quality data collected under ID and WA QAPPs will also be analyzed within the 2013-2017 five year trend report.

The 2013-2017 program consists of a basic monitoring component and several annual and periodic, rotational add-on elements incorporated as needed. The basic program consists of the highest priorities for annual monitoring, while the add-ons represent options for additional monitoring that are contingent on annual funding availability (e.g., the lower Flathead River monitoring station was added in 2013 and additional sites for the Statewide Monitoring Program may be added in the future). All monitoring activities to meet the Montana objectives were performed in accordance with the “Clark Fork River-Pend Oreille Watershed Water Quality Monitoring Program from Headwaters to Below Cabinet Gorge Dam – Quality Assurance Project Plan (QAPP)” (MDEQ, 2015) which is updated annually.

The objectives are met by: 1. Monthly monitoring: Avista collects monthly nutrients and field constituents at three lower Clark Fork River sites (excluding December, January, and February); 2. Peak flow monitoring: Avista collects nutrient samples at the Clark Fork River below Cabinet Gorge Dam during spring peak flow (six sampling events over a 1-month period in approximately May and/or June); 3. Summer monitoring: The City of Missoula and the University of Montana Watershed Clinic collect nutrient samples and field constituents in summer at nine Clark Fork River sites and one site on the Lower Flathead River (six sampling events, July-September; coordinated between the City of Missoula and UM); 4. Benthic algae monitoring: The UM Watershed Clinic collects summer benthic algae samples for chlorophyll-a and ash-free dry weight at seven Clark Fork River sites and one site on the lower Flathead River August-September.

Specifically, the CFRWQMC measures:  Nutrients: total phosphorus (TP), total persulfate nitrogen (TPN), nitrate + nitrite nitrogen

(NO2+NO3-N), dissolved ammonia nitrogen (NH3+NH4-N), and soluble reactive phosphorus (SRP).  Field parameters: water temperature (˚C), dissolved oxygen (mg/l), pH (standard units), redox potential (mv), specific conductance (μs/cm), total dissolved solids (mg/l), and turbidity (NTU).  Benthic algae: chlorophyll-a (mg/m2) and ash-free dry weight (g/m2).

All nutrient samples are analyzed by the City of Missoula Wastewater Treatment Plant lab and benthic algae samples are analyzed by the UM Watershed Health Clinic. Sampling, QA/QC and analytical methods are described in the Quality Assurance Project Plan (MDEQ 2015). MDEQ’s QA/QC Report for Clark Fork River Monitoring (May 13, 2015) is attached to this report and data qualifiers are noted in the 2014 CFR-BASIN Data Tables, attached. The locations of the monitoring stations are provided in Figure 1 and Table 1.

Figure 1. Clark Fork and Pend Oreille River Monitoring Sites. Note that only Clark Fork River sites (above Lake Pend Oreille) are included in this monitoring report.

4 Table 1. Monitoring Locations, Rationale, and Sampling Frequency on Clark Fork River and Tributaries Station Name Rationale Sampling Frequency CFR 2.5 Silver Bow Creek at Opportunity below mixing zone for Butte WWTP S6 upstream control site, start of Clark Fork CFR 07 Clark Fork below Warm Springs Creek S6 River upstream control site, upper river indicator CFR 09 Clark Fork at Deer Lodge C20, S6 site CFR 10 Clark Fork above Little Blackfoot River below mixing zone for Deer Lodge WWTP C20, S6 upper river site, between significant CFR 12 Clark Fork at Bonita (Beavertail Hill) C20, S6 tributaries below Blackfoot drainage, control site for CFR 15.5 Clark Fork above Missoula C20 S6 Missoula Clark Fork below Missoula (Tower Street CFR 18 below mixing zone for Missoula WWTP C20, S6 Conservation Area) lower river site, downstream of Missoula CFR 22 Clark Fork at Huson C20, S6 and Smurfit-Stone lower river site, upstream control for the CFR 25 Clark Fork above Flathead C20, S6 Flathead River Flathead River near Mouth (near Tribal CFR 26 Requested by EPA for TMDL purposes C20, S6 Boundary) lower river site, downstream of Flathead CFR 28 Clark Fork below Thompson Falls N9 River and Thompson Falls WWTP CFR 29 Clark Fork at Noxon Bridge lower river site, reflects reservoir influence N9 estimation of nutrient loading to Lake Pend CFR 30 Clark Fork below Cabinet Gorge Dam N15 Oreille CFR = Clark Fork River and its tributaries N9 = Monthly monitoring for nutrients and field constituents, 9 monthly samples (excludes December, January and February) N15 = Monthly monitoring for nutrients and field constituents, 9 monthly samples (excludes December, January and February) and Peak flow monitoring for nutrients, 6 peak flow samples C20 = Benthic algae monitoring for Chlorophyll-a and ash-free dry weight , 20 replicates per site, August and September S6 = Summer monitoring for nutrients and field constituents, 6 samples during July, August and September

4.0 DATA QUALITY CONTROL

Montana DEQ analyzes the monitoring data each year for quality assurance/quality control and provides a report (QA/QC Report for Clark Fork River Monitoring) that is appended to this report. This section briefly summarizes the results. Data flags from the QA/QC report are included in the 2014 CFR-BASIN Data Tables, also appended to this report. Nine data were flagged H for exceeding holding times. Seven blank samples had detects above the lower reporting limit and as a result, 18 data results were flagged B. Seven blanks had detects less than the lower reporting limit and above the method detection limit and as a result 36 data results were flagged J to indicate a greater level of uncertainty. Three data were flagged JB and one was flagged JH for the combination of issues. Four field duplicates exceeded a relative percent difference of 25%. Two of these were near or below the lower reporting limit where small differences become large percentages, and one is influenced by a blank sample above the

5 detection limit. Four samples failed logic checks where dissolved constituents exceed total results, but were generally within error range. Three of these were labeled D because differences are likely due to dilution required for analysis. Overall, 12 data were flagged D because the reporting limit was increased due to sample dilutions. There was no data flagged for laboratory issues, and the overall project DQOs and DQIs were met as set forth in the QAPP. There was no data that was determined to be unusable (rejected) in the validation process or lost due to sampler or laboratory error. The CFWQMC discussed ways to improve data quality and QA/QC reporting at their annual meeting, and the QAPP and SAPs were updated accordingly.

5.0 NUTRIENT RESULTS

5.1 TOTAL PHOSPHOROUS

Upper to middle Clark Fork sites were sampled by the City of Missoula and UM six times at approximate two week intervals from early July to mid-September. Lower Clark Fork sites were sampled by Avista at monthly intervals from mid-March to mid-November. Results of total phosphorous monitoring are presented in Figure 2 and in the 2014 CFR-BASIN Data Tables, attached. Total phosphorous is highest in Silver Bow Creek (range: 167.5 – 296.7 ug/L). Numeric standards for total phosphorous are established in ARM 17.30.631 on the mainstem of the Clark Fork River. From below Warm Springs Creek to the confluence of the Blackfoot River the total P standard is 20 ug/L. From the Blackfoot River to the confluence with the Flathead River, the total P standard is 39 ug/L. The standards are applicable from June 21 to September 21. All but one of the samples from the four upper Clark Fork River stations (below Warm Springs, at Deer Lodge, above Little Blackfoot and Bonita) exceeded the total phosphorous standard. Samples at these stations ranged from 19 ug/L to 233 ug/L. Nine of the 24 samples were double the standard or higher. None of the samples below Bonita exceeded the standard, and were generally lower overall and decreasing downstream with lowest concentrations in the Flathead River. Total P at these stations (above Missoula to the Flathead) ranged from 5.5 ug/L to 26.3 ug/L. Total P at the three lower Clark Fork stations was generally low with the exception of one sample in March below Thompson Falls (69.3ug/L). Excluding that sample, the range was 5.1 – 31.6 ug/L.

5.2 SOLUBLE REACTIVE PHOSPHOROUS

6 Site Mean Percentage SRP of Total Phosphorous Silver Bow Creek at Opportunity 77.8% Clark Fork below Warm Springs 66.6% Clark Fork at Deer Lodge 35.4% Clark Fork above Little Blackfoot 45.7% Clark Fork at Bonita (Beavertail Hill) 46.8% Clark Fork above Missoula 37.4% Clark Fork below Missoula 40.5% Clark Fork at Huson 33.1% Clark Fork above Flathead 39.7% Flathead River 29.6% Clark Fork below Thompson Falls 35.7% Clark Fork at Noxon 41.4% Clark Fork below Cabinet Gorge Dam 34.5%

5.3 TOTAL NITROGEN

Upper to middle Clark Fork sites were sampled by the City of Missoula and UM six times at approximate two week intervals from early July to mid-September. Lower Clark Fork sites were sampled by Avista at monthly intervals from mid-March to mid-November. Results of total nitrogen monitoring are presented in Figure 4 and in the 2014 CFR-BASIN Data Tables, attached. Total nitrogen concentrations were highest in Silver Bow Creek and were generally more than double other sites there (range: 896- 2586 ug/L). Numeric standards for total nitrogen are established in ARM 17.30.631 on the mainstem of the Clark Fork River from below Warm Springs Creek to the confluence of the Flathead River from June 21 to September 21. The total N standard is 300 ug/L. The standard was exceeded in 50% of the samples from the Clark Fork below Warm Springs (range: 194-387 ug/L), 100% of the samples from the Clark Fork at Deer Lodge (range: 306-370 ug/L), 50% of the samples from the Clark Fork above Little Blackfoot (range: 236-418 ug/L), and 16.7% of the samples from the Clark Fork at Bonita (range: 198- 321). Samples from all other stations met the standard. With the exception of one sample below Thompson Falls (TN = 586 ug/L), all other samples below the Bonita station ranged generally between 100-200 ug/L, with the Flathead River at the lower end of that range.

5.4 NITRATE + NITRITE

7 Site Mean Percentage Nitrate+Nitrate of Total Nitrogen Silver Bow Creek at Opportunity 99.2% Clark Fork below Warm Springs 5.3% Clark Fork at Deer Lodge 16% Clark Fork above Little Blackfoot 2.3% Clark Fork at Bonita 1.6% Clark Fork above Missoula 1.9% Clark Fork below Missoula 10.8% Clark Fork at Huson 12.8% Clark Fork above Flathead 6.1% Flathead River 8.3% Clark Fork below Thompson Falls 16.2% Clark Fork at Noxon 21.3% Clark Fork below Cabinet Gorge Dam 19.9%

5.5 AMMONIA

8 100 2014 Total Phosphorous 350 90 300 Summer - Silver Bow to Flathead 250

200 70 ug/L 150 60 100

50 50 Phosphorous Standard 0 40 Silver Bow Creek at 30 ug/LTotal Phosphorous Opportunity 20 10 0 Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Flathead River below River at River above River at River above River below River at River above River Warm Deer Lodge Little Bonita Missoula Missoula Huson Flathead Springs Blackfoot 100 2014 Total Phosphorous 90 Monthly - Lower Clark Fork

70 60 50 40 30

ug/LTotal Phosphorous 20

10 0 Clark Fork River below Thompson Clark Fork River at Noxon Clark Fork River below Cabinet Falls Gorge Dam

Figure 2: Total phosphorous results for summer nutrient monitoring (upper) and monthly nutrient monitoring (lower). Bars indicate sampling dates that range from early July to mid-September for Silver Bow to Flathead and mid-March to mid-November for the lower Clark Fork. See 2014 CFR-BASIN Data Tables for exact dates.

50 300

45 2014 Soluble Reactive Phosphorous 250 Summer - Silver Bow to Flathead

40 200

35 150

ug/L 30 100

25 50

20 0 15 Silver Bow Creek at Opportunity

10 ug/LSoluble Reactive Phosphorous 5

0 Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Flathead River below River at River above River at River aboveRiver below River at River above River Warm Deer Lodge Little Bonita Missoula Missoula Huson Flathead Springs Blackfoot

50 2014 Soluble Reactive Phosphorous

45 Monthly - Lower Clark Fork 40

35 30 25 20 15

ug/LSoluble Reactive Phosphorous 5

0 Clark Fork River below Thompson Clark Fork River at Noxon Clark Fork River below Cabinet Falls Gorge Dam

Figure 3: Soluble reactive phosphorous results for summer nutrient monitoring (upper) and monthly nutrient monitoring (lower). Bars indicate sampling dates that range from early July to mid-September for Silver Bow to Flathead and mid-March to mid-November for the lower Clark Fork. See 2014 CFR- BASIN Data Tables for exact dates.

600 3000

2014 Total Nitrogen 2000 500 Summer - Silver Bow to Flathead ug/L 1000

400 Silver Bow Creek at Nitrogen Standard 300 Opportunity

200 ug/LTotal Nitrogen

100

0 Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Flathead River River at River River at River River River at River River below Deer Lodgeabove Little Bonita above below Huson above Warm Blackfoot Missoula Missoula Flathead

Springs

600

2014 Total Nitrogen 500

Monthly - Lower Clark Fork

400

300

200 ug/LTotal Nitrogen

100

0 Clark Fork River below Thompson Clark Fork River at Noxon Clark Fork River below Cabinet Falls Gorge Dam

Figure 4: Total nitrogen results for summer nutrient monitoring (upper) and monthly nutrient monitoring (lower). Bars indicate sampling dates that range from early July to mid-September for Silver Bow to Flathead and mid-March to mid-November for the lower Clark Fork. See 2014 CFR-BASIN Data Tables for exact dates.

11 2500 140 2000

2014 Nitrate + Nitrite

120 1500 ug/L Summer - Silver Bow to Flathead 1000 100 500

0 80 Silver Bow

Creek at 60 Opportunity

ug/LNitrate Nitrite + 40

Springs

140 2014 Nitrate + Nitrite 120

Monthly - Lower Clark Fork 100

ug/LNitrate Nitrite + 40

Clark Fork River below Thompson Clark Fork River at Noxon Clark Fork River below Cabinet

Falls Gorge Dam

Figure 5: Nitrate+Nitrite results for summer nutrient monitoring (upper) and monthly nutrient monitoring (lower). Bars indicate sampling dates that range from early July to mid-September for Silver Bow to Flathead and mid-March to mid-November for the lower Clark Fork. See 2014 CFR-BASIN Data Tables for exact dates.

45 40 2014 Total Ammonia 30

40 Summer - Silver Bow to Flathead 20 35 ug/L

30 0 Silver Bow 25 Creek at 20 Opportunity

ug/LTotal Ammonia 10

Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Flathead

River River at River River at River River River at River River below Deer Lodge above Bonita above below Huson above Warm Little Missoula Missoula Flathead Springs Blackfoot

40 2014 Total Ammonia

35 Monthly - Lower Clark Fork

30 25

ug/LTotal Ammonia 10

0 Clark Fork River below Thompson Clark Fork River at Noxon Clark Fork River below Cabinet Falls Gorge Dam

Figure 6: Ammonia results for summer nutrient monitoring (upper) and monthly nutrient monitoring (lower). Bars indicate sampling dates that range from early July to mid-September for Silver Bow to Flathead and mid-March to mid-November for the lower Clark Fork. See 2014 CFR-BASIN Data Tables for exact dates.

13 6.0 BENTHIC ALGAE RESULTS

Benthic algae were sampled twice: once in late July-early August and again at the end of August-early September. Averages for chlorophyll-a and ash free dry weight from each sample date are shown in Figure 7. Individual sample results for specific dates are included in the 2014 CFR-BASIN Data Tables, attached. Numeric standards for benthic algae chlorophyll-a are established in ARM 17.30.631 on the Clark Fork River below Warm Springs Creek to the confluence of the Flathead River from June 21 to September 21. The standard for summer mean algal density is 100 mg/m2 and the standard for summer maximum density is 150 mg/m2. Algal density exceeded the summer mean standard at Deer Lodge (221 mg/m2) and Bonita (125 mg/m2). Algal density exceeded the summer maximum standard at Deer Lodge on August 3 (280 mg/m2) and August 31 (162 mg/m2), and at Bonita on August 3 (151 mg/m2). Although the maximum standard applies only to the average of multiple samples collected at a site on a given date, it is instructive to see how many of the individual samples exceeded 150 mg/m2. These are listed below.

Percent individual samples over Late July – early August Late August – early September 150 mg/m2 (not the same as standard exceedance – see discussion above) Deer Lodge 48% 50% Above Little Blackfoot 20% 11% Bonita 32% 25% Above Missoula 10% 20% Below Missoula 0% 30% Huson 0% 0% Above Flathead 0% 0% Flathead River 0% 0%

14 300 Benthic Algae Chorophyll-a 250

Upper Clark Fork to Flathead

200

150

100 mg/squaremeter

0 Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Clark Fork Flathead River at River above River at River above River below River at River above River Deer Lodge Little Bonita Missoula Missoula Huson Flathead Blackfoot

180

160 Benthic Algae Ash Free Dry Weight

140 Upper Clark Fork to Flathead

120

100

g/squaremeter 60

Figure 7: Benthic Algae Chlorophyll-a and Ash Free Dry Weight Results. Bars indicate average results for 2 sampling dates (1) late July-early August and (2) late August-early September. See 2014 CFR-BASIN Data Tables for exact dates.

15 7.0 PEAK FLOW NUTRIENT MONITORING

This section summarizes the results of a technical memorandum to Avista on nutrient loading to Lake Pend Oreille in 2014 (HydroSolutions, 2015, attached). Peak flow nutrient monitoring is done below the Cabinet Gorge Dam to estimate nutrient loading from the Clark Fork watershed in Montana to Lake Pend Oreille in Idaho per the Montana and Idaho Border Nutrient Load Memorandum of Agreement (Border Agreement), established in 2002. Nutrient targets established in the Border Agreement were developed to maintain water quality in the open waters of Lake Pend Oreille from the mouth of the Clark Fork River to the Long Bridge (Highway 95). The Border Agreement and the Montana and Idaho Border Nutrient Load Agreement Technical Guidance (Tri-State Water Quality Council 2001) are available on the Montana DEQ website at: http://www.deq.mt.gov/wqinfo/OtherWQLinks.mcpx. Nutrient targets are outlined in section VII of the Border Agreement as follows:  An area-weighted euphotic-zone average concentration of 7.3 μg/L total phosphorus (TP) for Lake Pend Oreille,  Total loading to Lake Pend Oreille of 328,651 kilograms per year (kg/year) total phosphorus,  259,500 kg/year total phosphorus from Montana (as measured at Clark Fork River below Cabinet Gorge Dam),  69,151 kg/year total phosphorus from Lake Pend Oreille watershed in Idaho,  Greater than 15:1 total nitrogen to total phosphorus ratio.

The Border Agreement establishes short-term and long-term exceedances of the established nutrient targets. As stated in the Border Agreement, an exceedance of the target exists when either of the following conditions is documented: 1) A short-term exceedance of the targets (three consecutive years of total phosphorus load increases at the border that are above the targets by greater than 10%). 2) A long-term exceedance of the targets (a ten year average total phosphorus concentration in the lake greater than 7.3 μg/L).

Every year the estimated annual TP load is evaluated against the Border Agreement’s nutrient load target for the Clark Fork River of 259,500 kg/year, and for short term exceedance of this target. The load estimation method is detailed in HydroSolutions, 2015. Results of the loading estimate for 2014 and the previous two years are presented in Table 2. In 2014 the estimated TP load exceeded the allocated target load of 259,500 kilograms per year by 0.4 percent. Since 1998 the estimated TP load has exceeded the allocated target load five times. All of the exceedances have occurred in the last eight years: in 2006, 2008, 2011, 2012, and 2014. Of those exceedances only estimated TP loads in 2011 and 2012 were greater than 110 percent of the target load as defined in the Border Agreement in evaluating short term exceedances. Based on this assessment there is no short term TP load exceedance in the past three years or any previous consecutive three year period since 1998.

16 Table 2: Estimated Lake Pend Oreille Nutrient Loads from the Clark Fork River 2012 to 2014 (From: HydroSolutions, 2015)

8.0 REFERENCES

HydroSolutions, 2015, Estimate of 2014 Nutrient Loading from Clark Fork River into Lake Pend Oreille, Technical Memorandum to Avista Corporation, May 7.

HydroSolutions, 2014, Clark Fork River Nutrient Water Quality Status and Trends Report, 1998—2012, Helena, MT.

Montana Department of Environmental Quality, 2015, QA/QC Report for Clark Fork River Monitoring, QAPP ID: WQPBQAP-10, Water Quality Planning Bureau, May 13.

Montana Department of Environmental Quality, 2015, Clark Fork River-Pend Oreille Watershed Water Quality Monitoring Program from Headwaters to Below Cabinet Gorge Dam – Quality Assurance Project Plan (QAPP).

U.S. Environmental Protection Agency, 1993, Clark Fork-Pend Oreille Basin Water Quality Study: A Summary of Findings and a Management Plan, EPA Region 10, Seattle, EPA 910/R-93-006.

QA/QC REPORT FOR CLARK FORK RIVER MONITORING

QAPP ID: WQPBQAP-10

MAY 13, 2015

Prepared for: Randy Apfelbeck, Clark Fork Monitoring Project Manager Montana Department of Environmental Quality Water Quality Planning Bureau Monitoring and Assessment Section

Prepared by: Terri Mavencamp, QA Officer Montana Department of Environmental Quality Water Quality Planning Bureau Quality Assurance Section

1 TABLE OF CONTENTS

1.0 Introduction ...... 2 2.0 Field Components ...... 3 Field Documentation...... 3 Chain of Custody Forms ...... Error! Bookmark not defined.4 Sample Sites ...... 4 Frequency of Field Blanks and Field Duplicates ...... 4 3.0 Sample Handling ...... 4 Preservation and Holding Times from SAPs/QAPP ...... 4 Field to Lab drop off ...... 6 Holding Times and H flagged data ...... 8 4.0 Analysis ...... 8 Required Analytical Methods ...... 8 Required Detection Limits ...... 9 Field Blanks ...... 9 Field Duplicates ...... 12 General Quality Checks ...... 12 Laboratory QC ...... 13 5.0 QC Summary ...... 13 Flagged Data ...... 13 Completeness...... 16 6.0 Recommended Corrective Actions ...... 16 Appendix A…………………………………………………………………………………………………………………………………………….16

1.0 INTRODUCTION

A data quality control (QC) review has been completed on all data collected and submitted to DEQ in 2014 for the Clark Fork River-Pend Oreille Watershed Water Quality Monitoring Program. Monitoring activities were performed in accordance with the “Clark Fork River-Pend

2 Oreille Watershed Water Quality Monitoring Program from Headwaters to Below Cabinet Gorge Dam – Quality Assurance Project Plan (QAPP)” (QAPP ID: WQPBQAP-10) and associated SAPs. The scope of the QC evaluation was to evaluate documentation associated with sampling and measurement (i.e., field logbooks and site visit forms) and laboratory analytical results to verify data quality. The QC evaluation includes a review of the data quality objectives (DQOs) and data quality indicators (DQIs) as outlined in the QAPP and follows the DEQ QA/QC program. The review also includes:  Review of field data sheets to verify calibration and to identify field notes that explain any deviations from the QAPP  Review of field notes and field data sheets for a data logic check and to identify any notes indicating deviations from the QAPP  Review of the sample delivery group to evaluate the overall quality of the data including reporting errors, data omissions, and suspect or anomalous values

The QC review applies to the monthly and peak flow nutrient monitoring by Avista and the summer nutrient monitoring by the City of Missoula and University of Montana.

2.0 FIELD COMPONENTS

FIELD DOCUMENTATION A review of City of Missoula field logbooks shows that the field meter was calibrated (typically 1-2 days before sampling) and checks performed daily prior to sampling. Some field notes were difficult to decipher and it would be easier if Missoula used a form similar to the Avista form and referred to the stations both by the name and by the station number. On 8/27/14, the turbidity readings were taken as an average of two readings and the oxygen reduction potential was very variable (+/- 100, outside the +/- 20 mV accuracy allowance). It was unclear from the field forms if the City of Missoula took grab samples or not.

Avista had field notes and the field measurement and calibration data was recorded and stored in the YSI instrument used to make the measurements. There was one turbidity reading above the turbidity range on 3/11/14. The field notes from 3.11.2014, were filled out as both 3.14.14(typed) and 5.14.14 (written). The samples were named cfr-30-031114-S and a chain of custody was attached to this from 5.6.14 for samples cfr 30 050614 S PF, but with only the sampler’s signature. The University of Montana submitted field forms with collection information for the benthic algae sample collections, and sample handling information. The station ID and lat/longs were clearly identified on the form. All samples were collected and went from ice to the freezer within 9 hours, and typically just 2-3 hours.

3 CHAIN OF CUSTODY FORMS Avista Overall, the chain-of-custody forms were easy to follow and filled out correctly by Avista. The Avista IDs on the COCs matched those in EQUIS.

University of Montana I received two University of Montana Chain of Custody forms from 8/1/2014 and 8/30/2014 for two sets of water chemistry samples. The sample IDs on the form from 8/1/14 did not match those in EQUIS, (Sample ID dates were one day off of actual collection time, 8/2 vs 8/1 and the sample IDs were changed in EQuIS to reflect sampling date). In addition, it appears that the blank, CFR-22-080214-QC-FB was mislabeled, because in EQUIS it was FHR-26-080114-QC-FB. There are no temperatures recorded on the COC forms, and therefore holding time exceedances could not be determined.

The sample handling was indicated on the field forms for the benthic algae samples, and all samples went from ice to the freezer within 9 hours.

The City of Missoula does not fill out chain of custody forms because the samples never leave the City’s possession. But, I don’t have an easy-to-follow record to track sample handling.

SAMPLE SITES Avista sample sites matched locations specified in the QAPP. University of Montana Sample sites matched the locations specified in the QAPP. Sites in the field notebook of the City of Missoula were referred to slightly differently than the other two samplers, and it is suggested that they refer to the sites by the station IDs as well as the name. It was unclear from the notebook where several sights were, e.g., McClays, Buckhouse.

FREQUENCY OF FIELD BLANKS AND FIELD DUPLICATES One field blank sample and one duplicate sample were collected for Avista (sites 28, 29 and 30), the City of Missoula (sites 7, 9, 10, 12, 15.5, 18, 2.5, 22, 25 and 26) and the University of Montana (22,25,26) for each monitoring event. This frequency met the frequency outlined in the requirements as described in the QAPP.

3.0 SAMPLE HANDLING

PRESERVATION AND HOLDING TIMES FROM SAPS/QAPP

4 The preservation outline in the QAPP, Table 1, did not agree with that outlined in the DEQ monitoring suite, Table 2, or in the individual SAPs, Table 3. It is recommended to change the preservation methods in the QAPP to reflect what is currently occurring in the field and to agree with the SAPs.

Table 1. Sample volumes, containers, preservation and holding times From QAPP Analyte Sample Volume Container Preservation Holding Time TPN 250 ml Acid-washed cool to 4°C 28 days polyethylene TP 500 ml Acid-washed Add H2SO4 to pH<2, 28 days polyethylene cool to 4°C NO2+NO3 and 250 ml Acid-washed Filter, cool to 4°C or 28 days NH3+NH4 polyethylene freeze SRP 250 ml Acid-washed Filter, cool to 4°C or 48 hours* polyethylene freeze *Holding

Table 2. Sample volumes, containers, preservation and holding times From DEQ Monitoring Suite Parameter Method Alt method RRL Holding Container Preservative time Total Persulfate A4500-N C A4500-N B 40 28 250ml ≤6oC (28d HT), Nitrogen (TPN) HDPE Freeze (45d HT) Dissolved EPA 365.1 A4500-P F 1 2 250ml Filt. 0.45 um, ≤6oC Orthophosphate as P HDPE (SRP) o Total Phosphorus as P EPA 365.1 A4500-P F 3 28 250 ml H2SO4 , ≤6 C or (TP) HDPE Freeze Nitrate-Nitrite as N EPA 353.2 A4500-NO3 F 10 NO2+NO3 Total Ammonia as N EPA 350.1 A4500-NH3 50 NH3+NH4 B,C,D,E,or G

Table 3. Sample volumes, containers, preservation and holding times From SAPs, 2014 Analytes Filtered? Bottle Size Container Preservation Holding Time and Storage TPN N 250 ml HDPE Bottle Cool to ≤ 4 °C 28 days (on ice)in field, then freeze solid TP N 500 ml HDPE Bottle H₂SO₄; Cool to 28 days ≤ 4 °C (on ice) SRP Y 250 ml HDPE Bottle Cool to ≤ 4 °C 28 days (on ice) in field; then Freeze solid Dissolved Y 250 ml HDPE Bottle Cool to ≤4 °C 28 days NO2+NO3 and (on ice)in field; NH3+NH4 then freeze solid

FIELD TO LAB DROP OFF Avista Sample delivery and check in at lab:

Red = sample handling error Green = good Orange = borderline

Samples taken on 3/11/14 from 12:54-3:42 were delivered to the lab 3/12/14 and accepted 3/13 at 9:30 the temp was 1.1 °C. This approaches the holding time for SRP and Nitrate/nitrite total ammonia and SRP should be frozen.

Samples delivered from Avista to City of Missoula on 4/15/14 were noted as being taken from 10:40- 12:40, and were delivered 4/15 and accepted 4/16 at 11:30 am at 6.5 °C. Nitrate/nitrite, total ammonia and SRP should be frozen.

Samples from 5/14 (?) from 10:20-1:12 were delivered to the lab on 5/16/14 at 12:30 at 12.8 °C, this exceeds the allowed temperature for all analytes and exceeds the time for SRP.

The samples taken at 5/16- 5/29 were delivered to the lab at 6/2. As is indicated on the COC, the samples were on ice/partially frozen (2.4-3.3 C). This exceeds the allowed holding time for SRP (2 days) and Nitrate/nitrite total ammonia and SRP should be frozen.

Samples taken 6/11 from 10:28-12:39 were delivered to the lab 6/11 at 1:30 and accepted 6/12/14 at 10:05 at 6.9-7.6C.

Samples taken 7/16/14 from 11:03- 1:43 were delivered to the lab at 7/16/14 and checked in 7/17/14 at 10:40 at 7.4C. Nitrate/nitrite total ammonia and SRP should be frozen-has 24 hr on ice then freeze been tested for accuracy of analytical results?

Samples taken 8/11/14 from 10:20 – 1:15 were delivered to the lab 8/13 at 1:00 and accepted on 8/14/14 at 10:17 (?). The temperature was 3.8C. This exceeds the holding time for SRP and Nitrate/nitrite, total ammonia and SRP should be frozen.

The samples taken 9/17/14 from 10:08 – 12:05 and delivered to the lab 9/17 at 12:45 and accepted 9/18 at 10:35 were at temp 2.C This exceeds the holding time for SRP. Nitrate/nitrite total ammonia and SRP should be frozen.

6 The samples taken 10/15/14 from 10:00 – 11:50 were delivered to the lab 10/15/14 at 12:30 and accepted 10/16 at 9:30. Temperature distilled water = 3.3 C. Nitrate/nitrite total ammonia and SRP should be frozen.

Samples taken 11/19/14 from 10:42-1:29 were delivered to the lab 11/19/14 at 2:05 and accepted 11/20/14 at 10:35 the temp was 4.5C. Nitrate/nitrite total ammonia and SRP should be frozen.

U of Mont:

Samples were delivered 2 days after collection. pH was checked and ok on all relevant bottles, but temperature was not recorded, so it was not possible to determine if HT was exceeded.

Laboratory holding times from delivery:

Avista: Table 4. Sample Handling Date Time samples Time lab Lab- OK? Date(s) of OK? taken checked in recorded lab analysis temp at sign +/- 1-2 d in 3.11.14 12:54-3:42 pm 3/13 Temp 1.1 C No, borderline Lab analysis Yes 9:30 am orthophosphate 3/26/2014 (maybe) Ok TP, TPN 4.15.14 10:40-12:40 4/16 Temp 6.5 C Ok TP, TPN 4/29/14 Yes 11:30 am

5.14.14 12:20-1:12 5/16 12.8 C No 5/28/14- Yes 12:30 6/4/14 TPN 7/9 No

5/16- 12:15, 11:52, 6/3/14 3.3 and 2.4 No 6/4-7/2 Some exceedances 5/23- 11:44, C OK TP for first 2 sampling 5/29/14 respectively Ok TPN dates see tbl 5

6/11/14 10:28-12:39 6/12 6.9-7.6 C No variable OK 6/6 1:30 1 exceedance for 6/6/ see tbl 5

7/16 11:03-1:43 7/17 7.4 C No 7/18-7/23 OK 10:40 am

8/11/14 10:20-1:15 8/14 3.8 C NO 8/14-8/22 1 FD exceedance 10_24 am Except TPN and (10/9) TP

7 9/17/14 10:00-12:05 9/18/14 2.0 C Borderline ortho 10/2-10/9 ok 10:35 am P Ok TPN and TP

10/15/14 10:00-11:50 10/16/14 3.3 C Borderline ortho 10/23-10/29 ok 9:30am P Ok TPN and TP

11/19/14 10:42-1:29 11/20 4.5C Borderline ortho 12/4-12/18 ok 10:35 am P Ok TPN and TP

HOLDING TIMES Analytical holding times were reviewed for Clark Fork River monthly, peak flow, and summer nutrient monitoring. The twelve samples identified in Table 4 were flagged H for exceeding the holding times. SRP were not flagged, because it was assumed that the holding time was 28 days if you put on ice and then freeze the samples.

Table 5. Samples that exceeded holding times and were flagged H. Activity ID Characteristic name Result value Unit Fraction flag CFR-30-050614-S-PF Nutrient-nitrogen 132 ug/l Total H CFR-30-051414-QC-FD Nutrient-nitrogen 219 ug/l Total H CFR-30-051414-S Nutrient-nitrogen 167 ug/l Total H CFR-30-051614-S-PF Orthophosphate 4 ug/l Dissolved H CFR-30-051614-S-PF Ammonia-nitrogen ND Dissolved H CFR-30-051614-S-PF Inorganic nitrogen 44.4 ug/l Dissolved H (nitrate and nitrite) CFR-30-051614-S-PF Phosphate- 13.2 ug/l Total H phosphorus

CFR-30-052314-S-PF Ammonia-nitrogen 7.2 ug/l Dissolved JH CFR-30-052314-S-PF Phosphate- 15.9 ug/l Total H phosphorus

CFR-30-052314-S-PF Inorganic nitrogen 35.2 ug/l Dissolved H (nitrate and nitrite) CFR-30-060614-S-PF Nutrient-nitrogen 278 ug/l Total H CFR-30-081114-QC-FD Nutrient-nitrogen 132 ug/l Total H

4.0 ANALYSIS

REQUIRED ANALYTICAL METHODS

8 All requested parameters specified in the SAPs were reported. The analytical analyses were not performed in accordance with methods defined in the QAPP (QAPP from 2013 need update?), but were performed in accordance with the methods defined in the individual 2014 SAPs.

Table 6. Analytical Methods Variations Parameter Analytical Method Defined in SAPs, Analytical Method Reported 2014 Total Phosphorus (TP) SM 4500 P H 4500-P-H Total Persulfate Nitrogen (TN) SM 4500 N (C) 4500-N-C Total Ammonia-Nitrogen (NH3) SM 4500 NH3 (H) 4500-NH3-H Soluble Reactive Phosphorus (SRP) SM 4500 P (G) 4500-P-G Nitrate + Nitrite-Nitrogen (NO2+NO3- SM 4500 NO3 (I) 4500-NO3-I N)

The TN method (4500-N-C) is an EPA-approved method and is a method used by DEQ. The methods for TP, SRP, NH3, and NO2+NO3-N methods are flow injection analysis (FIA) methods that are not EPA- approved. According to EPA, if you use a modification to an approved 40 CFR Part 136 method, the regulated community is allowed more flexibility to modify approved methods without EPA review. The automated wet chemistry FIA methods are considered as an acceptable alternative to equivalent segmented flow methods (which are EPA-approved methods).

REQUIRED DETECTION LIMITS The laboratory reporting limit met the project-required detection limits defined in the QAPP except where dilution increased the LRL.

FIELD BLANKS B – Flags:

The following field blanks had detects above the Lower reporting limit, and were therefore B flagged.

Table 7. Field blanks with detects above the lower reporting limit. Activity ID result Characteristic name LRL MDL CFR-30-071614-QC-FB 2.1 ug/l Inorganic nitrogen (nitrate and nitrite) 2 .8

CFR-30-091714-QC-FB 70 ug/L Nutrient-nitrogen 50 32.8

CFR-07-090314-QC-FB 2.6 Phosphate-phosphorus 1 0.86

CFR-10-080614-QC-FB 2 ug/L Inorganic nitrogen (nitrate and nitrite) 2 0.8

FHR-26-080114-QC-FB 15.7 Ammonia-nitrogen 10 7.6

9 FHR-26-080114-QC-FB 2.7 Inorganic nitrogen (nitrate and nitrite) 2 .8

FHR-26-082114-QC-FB 14.4 Ammonia-nitrogen 10 7.6

The following samples were B flagged for detections above the LRL in the associated blanks.

Table 8. Field samples with associated blank detects above the lower reporting limit. Activity ID Result ug/L Characteristic name LRL MDL CFR-07-080614-S 16 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-12-080614-S 4.8 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-15.5-080614-S 2.7 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-15.5-090314-S 16.9 Phosphate-phosphorus 1 0.86 CFR-22-080114-S 10.4 Ammonia-nitrogen 10 7.6 CFR-22-082114-S 11.4 Ammonia-nitrogen 10 7.6 CFR-25-080114-S 8.8 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-25-082114-S 17.5 Ammonia-nitrogen 10 7.6 CFR-28-071614-S 11.1 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-28-091714-S 125 Nutrient-nitrogen 50 32.8 CFR-29-071614-S 9.5 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-29-091714-S 153 Nutrient-nitrogen 50 32.8 CFR-30-071614-QC-FD 11.8 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-30-071614-S 12.7 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-30-091714-QC-FD 123 Nutrient-nitrogen 50 32.8 CFR-30-091714-S 120 Nutrient-nitrogen 50 32.8 FHR-26-080114-S 7.9 Inorganic nitrogen (nitrate and nitrite) 2 0.8 FHR-26-082114-QC-FD 14.8 Ammonia-nitrogen 10 7.6

J-Flags

The following blanks had detects above the minimum detection level and below the required reporting limit and are flagged as J.

Table 9. Blanks with detects less than the LRL and above the MDL. Activity ID result Characteristic name LRL MDL CFR-30-031114-QC-FB 1 Inorganic nitrogen (nitrate and nitrite) 2 .8

CFR-30-041514-QC-FB 6.3 Ammonia-nitrogen 10 6.1

CFR-30-052914-S-QC-FB 1 Inorganic nitrogen (nitrate and nitrite) 2 .8

CFR-30-061114-QC-FB .8 Inorganic nitrogen (nitrate and nitrite) 2 .8

CFR-30-071614-QC-FB 2.7 Phosphate-phosphorus 4 2.48

CFR-07-090314-QC-FB 1 Orthophosphate 2 .98

FHR-26-082114-QC-FB 1.4 Inorganic nitrogen (nitrate and nitrite) 2 .8

The following samples had detects above the minimum detection level and below the required reporting limit in the associated blanks and are therefore flagged as J, indicating an increased level of uncertainty.

Table 10. Samples with Blank detects less than the LRL and above the MDL. Activity ID Result ug/L Characteristic name LRL MDL CFR-07-071614-S 9.2 Ammonia-nitrogen 10 7.6 CFR-07-090314-QC-FB 1 Orthophosphate 2 0.98 CFR-09-071614-S 9.1 Ammonia-nitrogen 10 7.6 CFR-10-071614-S 9.2 Ammonia-nitrogen 10 7.6 CFR-10-080614-QC-FD 1.5 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-10-080614-S 1.4 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-10-082014-S 1.7 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-10-091714-S 7.8 Ammonia-nitrogen 10 7.6 CFR-12-082014-S 9.2 Ammonia-nitrogen 10 7.6 CFR-12-091714-S 8.9 Ammonia-nitrogen 10 7.6 CFR-12-091714-S 1.1 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-15.5-071614-S 8 Ammonia-nitrogen 10 7.6 CFR-15.5-082014-S 8.6 Ammonia-nitrogen 10 7.6 CFR-15.5-082014-S 1.1 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-15.5-091714-S 1.7 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-18-082114-S 8.2 Ammonia-nitrogen 10 7.6 CFR-25-070314-S 9.4 Ammonia-nitrogen 10 7.6 CFR-25-083014-S 9.3 Ammonia-nitrogen 10 7.6 CFR-25-091814-S 9.8 Ammonia-nitrogen 10 7.6 CFR-29-051414-S 9.2 Ammonia-nitrogen 10 6.1 CFR-29-061114-S 7.0 Ammonia-nitrogen 10 6.1 CFR-29-101514-S 8.4 Ammonia-nitrogen 10 7.6 CFR-30-031114-QC-FB 1 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-30-031114-S 9.3 Ammonia-nitrogen 10 6.1 CFR-30-041514-QC-FB 6.3 Ammonia-nitrogen 10 6.1 CFR-30-050614-S-PF 6.5 Ammonia-nitrogen 10 6.1 CFR-30-051414-QC-FD 8.7 Ammonia-nitrogen 10 6.1 CFR-30-051414-S 8.5 Ammonia-nitrogen 10 6.1 CFR-30-052314-S-PF 7.2 Ammonia-nitrogen 10 6.1 CFR-30-052914-S-QC-FB 1 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-30-060614-S-PF 7.9 Ammonia-nitrogen 10 6.1 CFR-30-061114-QC-FB 0.8 Inorganic nitrogen (nitrate and nitrite) 2 0.8 CFR-30-061114-QC-FD 6.8 Ammonia-nitrogen 10 6.1 CFR-30-071614-QC-FB 2.7 Phosphate-phosphorus 4 2.48 CFR-7-082014-S 8 Ammonia-nitrogen 10 7.6 FHR-26-070314-S 1.4 Orthophosphate 2 0.98 FHR-26-071714-S 1.3 Orthophosphate 2 0.98 FHR-26-080114-S 1.8 Orthophosphate 2 0.98 FHR-26-082114-QC-FB 1.4 Inorganic nitrogen (nitrate and nitrite) 2 0.8 FHR-26-082114-S 1.9 Orthophosphate 2 0.98

FIELD DUPLICATES The following field duplicates were outside of the data quality objective for relative differences of field blanks as specified in the QAPP, field duplicates must be < 25%.

Table 11. Field duplicates with relative differences above 25%. Activity ID result Characteristic name LRL MDL Relative % Data Difference Qualifier? CFR-30-061114- 6.8 Ammonia-nitrogen 10 6.1 From 82-12.7% None QC-FD Depending on the ND (from CFR-30-061114-S ND Ammonia-nitrogen 10 6.1 3.1ug/L to 6 none ug/L, respectively)

CFR-10-080614- 12.4 Ammonia-nitrogen 10 6.1 From 1,200 – None QC-FD 69.6% RPD for ND=3.1 ug/L to 6 CFR-10-080614-S nd Ammonia-nitrogen 10 6.1 ug/L none

CFR-15.5- 177 Nutrient-nitrogen 50 32.8 None 070214-QC-FD RPD = 71.3% CFR-15.5- 84 Nutrient-nitrogen 50 32.8 none 070214-S

FHR-26-082114- 14.8 Ammonia-nitrogen 10 7.6 blank = 14.4 B QC-FD

FHR-26-082114- ND Ammonia-nitrogen 10 7.6 B S

General Quality Checks:

Table 12. Logic checks Activity ID result Characteristic name LRL MDL Data Qualifier? CFR-07-090314-S 33.1 Orthophosphate 2 .98 None

CFR-07-090314-S 29.6 Phosphate- 1 .86 none phosphorous

These are so close, it is possible that all of the phosphate was orthophosphate.

12 Activity ID result Characteristic name LRL MDL Data Qualifier? CFR-2.5-082014- 252 Orthophosphate 4 .98 D S

CFR-2.5-082014- 232.9 Phosphate- 4 .98 S phosphorous

Again, these are so close, see comment above. Activity ID result Characteristic name LRL MDL Data Qualifier? CFR-2.5-090314- 100 D S 1185 Nutrient-nitrogen 32.8 CFR-2.5-090314- 10 S 13 Ammonia-nitrogen 7.6 CFR-2.5-090314- Inorganic nitrogen 40 D S 1892.3 (nitrate and nitrite) 0.8 These data are enough out that they could be flagged “J” Activity ID result Characteristic name LRL MDL Data Qualifier? FHR-26-073114- FM 0.3 Specific conductance FHR-26-073114- FM 0 Total dissolved solids

LABORATORY QC

The Missoula Waste Water Treatment Plant Laboratory quality control summary was reviewed. Laboratory QC including lab control blanks, laboratory control standards, replicates and matrix spikes were evaluated to determine the usability of the data for each analysis. All laboratory QC was within limits specified by the specific analytical methods and the QAPP.

5.0 QC SUMMARY

FLAGGED DATA The overall project data had 9 data flagged “H” for exceeding holding times and 18 data flagged “B” for field blank contamination. In the electronic data deliverable, there are 12 data flagged “D” because the reporting limit was increased due to sample dilutions. Also in the electronic data deliverable there are 36 data that had reported values between the method detection limit and the reporting limit were flagged “J”. Three data were flagged for JB and one for JH. There was no data flagged for laboratory issues. The overall project DQOs and DQIs were met as set forth in the QAPP. A summary of the flagged data is shown in Table 4 below.

13 Table 13. Flagged Data in the Electronic Data Deliverable

Sample ID Parameter Data Flag CFR-30-050614-S-PF Nutrient-nitrogen H CFR-30-051414-QC-FD Nutrient-nitrogen H CFR-30-051414-S Nutrient-nitrogen H CFR-30-051614-S-PF Orthophosphate H CFR-30-051614-S-PF Ammonia-nitrogen H CFR-30-051614-S-PF Inorganic nitrogen (nitrate and nitrite) H CFR-30-052314-S-PF Inorganic nitrogen (nitrate and nitrite) H CFR-30-060614-S-PF Nutrient-nitrogen H CFR-30-051614-S-PF Phosphate-phosphorus H

CFR-30-052314-S-PF Phosphate-phosphorus H

CFR-30-081114-QC-FD Nutrient-nitrogen H

CFR-28-071614-S Inorganic nitrogen (nitrate and nitrite) B CFR-28-091714-S Nutrient-nitrogen B CFR-29-071614-S Inorganic nitrogen (nitrate and nitrite) B CFR-29-091714-S Nutrient-nitrogen B CFR-30-071614-QC-FD Inorganic nitrogen (nitrate and nitrite) B CFR-30-071614-S Inorganic nitrogen (nitrate and nitrite) B CFR-30-091714-QC-FD Nutrient-nitrogen B CFR-30-091714-S Nutrient-nitrogen B CFR-07-080614-S Inorganic nitrogen (nitrate and nitrite) B CFR-12-080614-S Inorganic nitrogen (nitrate and nitrite) B CFR-15.5-080614-S Inorganic nitrogen (nitrate and nitrite) B CFR-15.5-090314-S Phosphate-phosphorus B CFR-22-080114-S Ammonia-nitrogen B CFR-22-082114-S Ammonia-nitrogen B CFR-25-080114-S Inorganic nitrogen (nitrate and nitrite) B CFR-25-082114-S Ammonia-nitrogen B FHR-26-080114-S Inorganic nitrogen (nitrate and nitrite) B FHR-26-082114-QC-FD Ammonia-nitrogen B

CFR-2.5-070214-S Inorganic nitrogen (nitrate and nitrite) D CFR-2.5-071614-S Nutrient-nitrogen D CFR-2.5-071614-S Inorganic nitrogen (nitrate and nitrite) D CFR-2.5-082014-S Orthophosphate D CFR-2.5-082014-S Nutrient-nitrogen D CFR-2.5-082014-S Inorganic nitrogen (nitrate and nitrite) D CFR-2.5-090314-S Orthophosphate D CFR-2.5-090314-S Nutrient-nitrogen D

14 Table 13. Flagged Data in the Electronic Data Deliverable

Sample ID Parameter Data Flag CFR-2.5-090314-S Inorganic nitrogen (nitrate and nitrite) D CFR-2.5-091714-S Orthophosphate D CFR-2.5-091714-S Nutrient-nitrogen D CFR-2.5-091714-S Inorganic nitrogen (nitrate and nitrite) D

CFR-29-051414-S Ammonia-nitrogen J CFR-29-061114-S Ammonia-nitrogen J CFR-29-101514-S Ammonia-nitrogen J CFR-30-031114-QC-FB Inorganic nitrogen (nitrate and nitrite) J CFR-30-031114-S Ammonia-nitrogen J CFR-30-041514-QC-FB Ammonia-nitrogen J CFR-30-050614-S-PF Ammonia-nitrogen J CFR-30-051414-QC-FD Ammonia-nitrogen J CFR-30-051414-S Ammonia-nitrogen J CFR-30-052914-S-QC-FB Inorganic nitrogen (nitrate and nitrite) J CFR-30-060614-S-PF Ammonia-nitrogen J CFR-30-061114-QC-FB Inorganic nitrogen (nitrate and nitrite) J CFR-30-061114-QC-FD Ammonia-nitrogen J CFR-30-071614-QC-FB Phosphate-phosphorus J CFR-07-071614-S Ammonia-nitrogen J CFR-07-090314-QC-FB Orthophosphate J CFR-09-071614-S Ammonia-nitrogen J CFR-10-071614-S Ammonia-nitrogen J CFR-10-082014-S Inorganic nitrogen (nitrate and nitrite) J CFR-10-091714-S Ammonia-nitrogen J CFR-12-082014-S Ammonia-nitrogen J CFR-12-091714-S Ammonia-nitrogen J CFR-12-091714-S Inorganic nitrogen (nitrate and nitrite) J CFR-15.5-071614-S Ammonia-nitrogen J CFR-15.5-082014-S Ammonia-nitrogen J CFR-15.5-082014-S Inorganic nitrogen (nitrate and nitrite) J CFR-15.5-091714-S Inorganic nitrogen (nitrate and nitrite) J CFR-25-070314-S Ammonia-nitrogen J CFR-25-083014-S Ammonia-nitrogen J CFR-25-091814-S Ammonia-nitrogen J CFR-7-082014-S Ammonia-nitrogen J FHR-26-070314-S Orthophosphate J FHR-26-071714-S Orthophosphate J FHR-26-080114-S Orthophosphate J FHR-26-082114-QC-FB Inorganic nitrogen (nitrate and nitrite) J FHR-26-082114-S Orthophosphate J

15 Table 13. Flagged Data in the Electronic Data Deliverable

Sample ID Parameter Data Flag

CFR-10-080614-QC-FD Inorganic nitrogen (nitrate and nitrite) JB CFR-10-080614-S Inorganic nitrogen (nitrate and nitrite) JB CFR-18-082114-S Ammonia-nitrogen JB CFR-30-052314-S-PF Ammonia-nitrogen JH

COMPLETENESS There was no data that was determined to be unusable (rejected) in the validation process or lost due to sampler or laboratory error.

6.0 RECOMMENDED CORRECTIVE ACTIONS

As a result of the QA review, the following are recommended actions: ▪ The City of Missoula should use a field note format similar to Avista for clarity; grab samples should be reported and the stations should be referred to by name and number. ▪ University of Montana Benthic Algae Chain of Custody & field forms need to be filled out for QC on sample handling, sample sites, etc, to be carried out. ▪ Sample handling for the City of Missoula could not be reviewed, as there was not sufficient documentation, no COC (alternatively, sample handling could be documented on the field notes, e.g., samples were frozen at -20C at 10:30, except for TPN and TP, which were stored in the fridge at 4 C). ▪ Provide documentation that the current sample handling does not affect results.

▪ To increase holding time above 0 °C, consider adding H2SO4 to Nitrate-Nitrite(N) and total Ammonia. But, SRP would still need to be frozen.

Appendix A. Data Result Qualifiers:

Table A-1 Data Result Qualifiers. Result Result Qualifier Description Qualifier B Detection in field blank D Reporting limit increased due to sample matrix H EPA holding time exceeded J Estimated: The analyte was positively identified and the associated numerical value is the approximate concentration of the analyte in the sample. R Rejected: The sample results are unusable due to the quality of the data generated because certain criteria were not met. The analyte may or may not be present in the sample.

16 2014 Clark Fork River Basin Nutrient Monitoring Data Tables

Field blanks are yellow; Duplicate nutrient samples are blue; Peak flow samples below Cabinet Gorge are gray; Numeric standard exceedances for TN and TP are in pink Data Qualifiers: H – exceeded holding time; B – field blank contamination; D – reporting limit increased due to sample dilution; J – between method detection limit and reporting limit Nitrate and nitrite Total Persulfate Orthophosphate Total Phosphorus Station Name Start Date Sample Type Ammonia (ug/l) (ug/l) Nitrogen (ug/l) (ug/l) (ug/l) Silver Bow Creek at Opportunity 7/2/2014 Routine Sample 20.8 1264.5 D 1252 130.7 167.5 Silver Bow Creek at Opportunity 7/16/2014 Routine Sample 12.6 907.8 D 1263 D 143.3 175.6 Silver Bow Creek at Opportunity 8/6/2014 Routine Sample 22.2 316.3 896 143.8 205.8 Silver Bow Creek at Opportunity 8/20/2014 Routine Sample 32.4 1383.5 D 974 D 252 D 232.9 Silver Bow Creek at Opportunity 9/3/2014 Routine Sample 13 1892.3 D 1185 D 152.2 D 204.6 Silver Bow Creek at Opportunity 9/17/2014 Field Blank < 10 < 2 < 50 < 2 < 1 Silver Bow Creek at Opportunity 9/17/2014 Routine Sample 20.7 2211.3 D 2586 D 161.7 D 296.7

Clark Fork River below Warm Springs 7/2/2014 Routine Sample < 10 14.3 194 16 28.3 Clark Fork River below Warm Springs 7/16/2014 Routine Sample 9.2 J 21.7 290 24.3 45.1 Clark Fork River below Warm Springs 8/6/2014 Routine Sample 13.1 16 B 311 38.5 61.8 Clark Fork River below Warm Springs 8/20/2014 Routine Sample 8 J 10.4 303 33 52.5 Clark Fork River below Warm Springs 9/3/2014 Field Blank < 10 < 2 < 50 1 J 2.6 Clark Fork River below Warm Springs 9/3/2014 Field Duplicate < 10 15.8 268 33.4 33.6 Clark Fork River below Warm Springs 9/3/2014 Routine Sample < 10 15.4 278 33.1 29.6 Clark Fork River below Warm Springs 9/17/2014 Routine Sample 14.6 10.2 387 35.1 66.9

Clark Fork River at Deer Lodge 7/2/2014 Routine Sample < 10 39.6 306 15.5 42.5 Clark Fork River at Deer Lodge 7/16/2014 Routine Sample 9.1 J 60.9 370 17.3 37.2 Clark Fork River at Deer Lodge 8/6/2014 Routine Sample 17.1 70.2 310 7.8 19 Clark Fork River at Deer Lodge 8/20/2014 Field Blank < 10 < 2 < 50 < 2 < 4 Clark Fork River at Deer Lodge 8/20/2014 Routine Sample 15.2 54 330 13.7 30.9 Clark Fork River at Deer Lodge 9/3/2014 Routine Sample < 10 43.5 314 8.8 94.9 Clark Fork River at Deer Lodge 9/17/2014 Routine Sample 12.1 43.9 326 8.7 25

Clark Fork River above Little Blackfoot 7/2/2014 Routine Sample < 10 45.2 418 27.6 69.5 Clark Fork River above Little Blackfoot 7/16/2014 Routine Sample 9.2 J 5.2 294 27.2 45.7 Clark Fork River above Little Blackfoot 8/6/2014 Field Blank < 10 2 < 50 < 2 < 4 Nitrate and nitrite Total Persulfate Orthophosphate Total Phosphorus Station Name Start Date Sample Type Ammonia (ug/l) (ug/l) Nitrogen (ug/l) (ug/l) (ug/l) Clark Fork River above Little Blackfoot 8/6/2014 Field Duplicate 12.4 1.5 JB 243 17.3 30.2 Clark Fork River above Little Blackfoot 8/6/2014 Routine Sample < 10 1.4 JB 236 16.9 30.1 Clark Fork River above Little Blackfoot 8/20/2014 Routine Sample 12.1 1.7 J 311 18.7 33.9 Clark Fork River above Little Blackfoot 9/3/2014 Routine Sample < 10 < 2 282 10.4 33.2 Clark Fork River above Little Blackfoot 9/17/2014 Routine Sample 7.8 J < 2 321 8.5 26.1

Clark Fork River at Bonita 7/2/2014 Routine Sample < 10 5.5 321 22 59.4 Clark Fork River at Bonita 7/16/2014 Field Blank < 10 < 2 < 50 < 2 < 4 Clark Fork River at Bonita 7/16/2014 Field Duplicate < 10 4 201 23.2 40 Clark Fork River at Bonita 7/16/2014 Routine Sample < 10 4.2 217 24.9 39.3 Clark Fork River at Bonita 8/6/2014 Routine Sample 26.1 4.8 B 198 16.8 30.6 Clark Fork River at Bonita 8/20/2014 Routine Sample 9.2 J 4.3 263 17.7 36.4 Clark Fork River at Bonita 9/3/2014 Routine Sample < 10 4.3 260 16.4 37.6 Clark Fork River at Bonita 9/17/2014 Routine Sample 8.9 J 1.1 J 226 7.3 21.9

Clark Fork River above Missoula 7/2/2014 Field Blank < 10 < 2 < 50 < 2 < 4 Clark Fork River above Missoula 7/2/2014 Field Duplicate < 10 4.3 177 10.1 24.4 Clark Fork River above Missoula 7/2/2014 Routine Sample < 10 4.3 84 9.3 26.3 Clark Fork River above Missoula 7/16/2014 Routine Sample 8 J 2.7 165 7.8 16.6 Clark Fork River above Missoula 8/6/2014 Routine Sample 16.7 2.7 B 133 3.5 11.5 Clark Fork River above Missoula 8/20/2014 Routine Sample 8.6 J 1.1 J 170 5.1 11.6 Clark Fork River above Missoula 9/3/2014 Routine Sample < 10 2 215 5.7 16.9 B Clark Fork River above Missoula 9/17/2014 Routine Sample 10.8 1.7 J 164 4.9 14.5

Clark Fork River below Missoula 7/3/2014 Routine Sample < 10 8.6 155 8 22.9 Clark Fork River below Missoula 7/17/2014 Routine Sample < 10 10 135 8.5 17.6 Clark Fork River below Missoula 8/7/2014 Routine Sample 13.1 23.7 162 3.9 12.7 Clark Fork River below Missoula 8/21/2014 Routine Sample 8.2 JB 19.6 156 6.6 16 Clark Fork River below Missoula 9/4/2014 Routine Sample 10.5 28.9 224 6.7 15.6 Clark Fork River below Missoula 9/18/2014 Routine Sample 15.4 25.4 218 10.3 22.9

Clark Fork River at Huson 7/3/2014 Routine Sample < 10 24.1 168 7.8 20.6

1 Nitrate and nitrite Total Persulfate Orthophosphate Total Phosphorus Station Name Start Date Sample Type Ammonia (ug/l) (ug/l) Nitrogen (ug/l) (ug/l) (ug/l) Clark Fork River at Huson 7/17/2014 Routine Sample < 10 10.1 159 7 14.2 Clark Fork River at Huson 8/1/2014 Routine Sample 10.4 B 37.6 178 5.2 15.2 Clark Fork River at Huson 8/21/2014 Routine Sample 11.4 B 18.2 165 3.4 12.5 Clark Fork River at Huson 8/30/2014 Routine Sample < 10 8.4 169 4 17.9 Clark Fork River at Huson 9/18/2014 Routine Sample 12.3 45 236 4.1 14.8

Clark Fork River above Flathead 7/3/2014 Routine Sample 9.4 J 15.4 136 7 17.5 Clark Fork River above Flathead 7/17/2014 Routine Sample < 10 7 182 3.6 10.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 10 8.8 B 266 3 7.8 Clark Fork River above Flathead 8/21/2014 Routine Sample 17.5 B 11.1 134 3.2 9.3 Clark Fork River above Flathead 8/30/2014 Field Blank < 10 < 2 < 50 < 2 < 1 Clark Fork River above Flathead 8/30/2014 Routine Sample 9.3 J 6.3 136 3.9 12.1 Clark Fork River above Flathead 9/18/2014 Field Blank < 10 < 2 < 50 < 2 < 1 Clark Fork River above Flathead 9/18/2014 Field Duplicate 11.8 7.7 148 3.6 8.2 Clark Fork River above Flathead 9/18/2014 Routine Sample 9.8 J 7.7 141 4.6 7.9

Clark Fork River below Thompson Falls 3/11/2014 Routine Sample 42.0 141.3 586 17.6 69.3 Clark Fork River below Thompson Falls 4/15/2014 Routine Sample < 10 26.3 221 4.7 31.6 Clark Fork River below Thompson Falls 5/14/2014 Routine Sample < 10 35.9 222 3.5 21.6 Clark Fork River below Thompson Falls 6/11/2014 Routine Sample < 10 32 179 6 22.8 Clark Fork River below Thompson Falls 7/16/2014 Routine Sample < 10 11.1 B 139 2.2 8.8 Clark Fork River below Thompson Falls 8/11/2014 Routine Sample < 10 6.4 143 2 6.8 Clark Fork River below Thompson Falls 9/17/2014 Routine Sample < 10 9.6 125 B 2.5 7.2 Clark Fork River below Thompson Falls 10/15/2014 Routine Sample < 10 14.9 107 4.1 5.7 Clark Fork River below Thompson Falls 11/19/2014 Routine Sample < 10 66.2 158 3.7 4.8

Clark Fork River at Noxon 3/11/2014 Routine Sample 10.1 62.5 152 2.2 6.9 Clark Fork River at Noxon 4/15/2014 Routine Sample < 10 8.7 126 2.8 11.9 Clark Fork River at Noxon 5/14/2014 Routine Sample 9.2 J 42.8 173 3.8 14.6 Clark Fork River at Noxon 6/11/2014 Routine Sample 7.0 J 33.4 162 4.4 13.1 Clark Fork River at Noxon 7/16/2014 Routine Sample < 10 9.5 B 138 2.2 13.7 Clark Fork River at Noxon 8/11/2014 Routine Sample 19.1 16.3 132 4 9.6

2 Nitrate and nitrite Total Persulfate Orthophosphate Total Phosphorus Station Name Start Date Sample Type Ammonia (ug/l) (ug/l) Nitrogen (ug/l) (ug/l) (ug/l) Clark Fork River at Noxon 9/17/2014 Routine Sample 14.8 46 153 B 5.1 9.9 Clark Fork River at Noxon 10/15/2014 Routine Sample 8.4 J 27.6 118 4.1 5.1 Clark Fork River at Noxon 11/19/2014 Routine Sample < 10 34.3 135 3.8 5.6

Clark Fork River below Cabinet Gorge Dam 3/11/2014 Field Blank < 10 1 J < 50 < 2 < 4 Clark Fork River below Cabinet Gorge Dam 3/11/2014 Field Duplicate 10.9 66.3 184 2.2 9.6 Clark Fork River below Cabinet Gorge Dam 3/11/2014 Routine Sample 9.3 J 67.7 187 2.5 8.9 Clark Fork River below Cabinet Gorge Dam 4/15/2014 Field Blank 6.3 J < 2 < 50 < 2 < 4 Clark Fork River below Cabinet Gorge Dam 4/15/2014 Field Duplicate < 10 5.9 122 2.1 10 Clark Fork River below Cabinet Gorge Dam 4/15/2014 Routine Sample < 10 5.5 118 2.3 10 Clark Fork River below Cabinet Gorge Dam 5/6/2014 Peak Flow 6.5 J 24.5 132 H 2.4 12.1 Clark Fork River below Cabinet Gorge Dam 5/14/2014 Field Blank < 10 < 2 < 50 < 2 < 4 Clark Fork River below Cabinet Gorge Dam 5/14/2014 Field Duplicate 8.7 J 43.4 219 H 3.8 15.3 Clark Fork River below Cabinet Gorge Dam 5/14/2014 Routine Sample 8.5 J 45.6 167 H 3.8 15.5 Clark Fork River below Cabinet Gorge Dam 5/16/2014 Peak Flow < 10 H 44.4 H 171 4 H 13.2 H Clark Fork River below Cabinet Gorge Dam 5/23/2014 Peak Flow 7.2 JH 35.2 H 225 4.4 15.9 H Clark Fork River below Cabinet Gorge Dam 5/29/2014 Peak Flow 12.0 40 187 5.6 23.2 Clark Fork River below Cabinet Gorge Dam 5/29/2014 Field Blank < 10 1 J < 50 < 2 < 4 Clark Fork River below Cabinet Gorge Dam 5/29/2014 Field Duplicate 14.4 45 222 6.3 21.8 Clark Fork River below Cabinet Gorge Dam 6/6/2014 Peak Flow 7.9 J 38.5 278 H 4.1 14.8 Clark Fork River below Cabinet Gorge Dam 6/10/2014 Peak Flow < 10 35.7 139 3.9 13.3 Clark Fork River below Cabinet Gorge Dam 6/11/2014 Field Blank < 10 0.8 < 50 < 2 < 4 Clark Fork River below Cabinet Gorge Dam 6/11/2014 Field Duplicate 6.8 34.5 138 4.5 12.9 Clark Fork River below Cabinet Gorge Dam 6/11/2014 Routine Sample < 10 32.6 146 4.5 12.1 Clark Fork River below Cabinet Gorge Dam 7/16/2014 Field Blank < 10 2.1 < 50 < 2 2.7 J Clark Fork River below Cabinet Gorge Dam 7/16/2014 Field Duplicate < 10 11.8 B 124 2.2 8.7 Clark Fork River below Cabinet Gorge Dam 7/16/2014 Routine Sample < 10 12.7 B 115 2.5 8.9 Clark Fork River below Cabinet Gorge Dam 8/11/2014 Field Blank < 10 < 2 < 50 < 2 < 4 Clark Fork River below Cabinet Gorge Dam 8/11/2014 Field Duplicate < 10 18.2 132 H 2.3 7.9 Clark Fork River below Cabinet Gorge Dam 8/11/2014 Routine Sample < 10 17.4 159 2 7.6 Clark Fork River below Cabinet Gorge Dam 9/17/2014 Field Blank < 10 < 2 70 < 2 < 1 Clark Fork River below Cabinet Gorge Dam 9/17/2014 Field Duplicate < 10 15.3 123 B 3.5 8.3

3 Nitrate and nitrite Total Persulfate Orthophosphate Total Phosphorus Station Name Start Date Sample Type Ammonia (ug/l) (ug/l) Nitrogen (ug/l) (ug/l) (ug/l) Clark Fork River below Cabinet Gorge Dam 9/17/2014 Routine Sample < 10 16 120 B 3.1 8.3 Clark Fork River below Cabinet Gorge Dam 10/15/2014 Field Blank < 10 < 2 < 50 < 2 < 1 Clark Fork River below Cabinet Gorge Dam 10/15/2014 Field Duplicate < 10 27.6 120 3.3 5.8 Clark Fork River below Cabinet Gorge Dam 10/15/2014 Routine Sample < 10 27.3 108 3.2 6.8 Clark Fork River below Cabinet Gorge Dam 11/19/2014 Field Blank < 10 < 2 < 50 < 2 < 1 Clark Fork River below Cabinet Gorge Dam 11/19/2014 Field Duplicate < 10 32.8 123 2.7 5.2 Clark Fork River below Cabinet Gorge Dam 11/19/2014 Routine Sample < 10 33.3 118 3.1 5.3

Flathead River 7/3/2014 Routine Sample < 10 15.1 120 1.4 J 7.6 Flathead River 7/17/2014 Routine Sample < 10 7 112 1.3 J 8.1 Flathead River 8/1/2014 Field Blank 15.7 2.7 < 50 < 2 < 4 Flathead River 8/1/2014 Routine Sample < 10 7.9 B 108 1.8 J 5.5 Flathead River 8/21/2014 Field Blank 14.4 1.4 J < 50 < 2 < 4 Flathead River 8/21/2014 Field Duplicate 14.8 B 9.1 127 2.1 5.8 Flathead River 8/21/2014 Routine Sample < 10 8.4 134 1.9 J 6.8 Flathead River 8/30/2014 Routine Sample < 10 6.9 96 2.2 4.9 Flathead River 9/18/2014 Routine Sample 14 13.6 130 2.5 6.7

2014 CFR-BASIN Field Measurement Results

Dissolved Oxidation Specific Total oxygen reduction pH conductance Temperature, dissolved Turbidity Station Name Start Date Activity Type (mg/l) potential (mV) (s.u.) (uS/cm) water (deg C) solids (mg/l) (NTU) Silver Bow Creek at Opportunity 7/2/2014 Field 10.08 -409.4 8.57 371.4 20.8 241.2 3.87 Silver Bow Creek at Opportunity 7/16/2014 Field 9.27 18.7 8.59 412.4 21.1 267.8 4.5 Silver Bow Creek at Opportunity 8/6/2014 Field 11.24 167.9 9.24 513 22.9 333.5 3.51 Silver Bow Creek at Opportunity 8/20/2014 Field 8.69 197.4 8.52 526 19.4 341.9 6.55 Silver Bow Creek at Opportunity 9/3/2014 Field 11.22 196.8 8.38 519 14.5 337.3 6.65 Silver Bow Creek at Opportunity 9/17/2014 Field 11.50 230.9 8.69 565 15.5 367.3 6.74

4 Dissolved Oxidation Specific Total oxygen reduction pH conductance Temperature, dissolved Turbidity Station Name Start Date Activity Type (mg/l) potential (mV) (s.u.) (uS/cm) water (deg C) solids (mg/l) (NTU) Clark Fork River below Warm Springs 7/2/2014 Field 9.76 -413.7 8.44 207.8 15.8 135.2 2.84 Clark Fork River below Warm Springs 7/16/2014 Field 8.87 250.9 8.56 255.9 17.0 166.4 3.29 Clark Fork River below Warm Springs 8/6/2014 Field 9.28 88.8 9.00 347 19.3 225.6 2.96 Clark Fork River below Warm Springs 8/20/2014 Field 9.83 195.4 8.90 356 16.9 231.4 2.83 Clark Fork River below Warm Springs 9/3/2014 Field 10.89 163.9 8.96 363.6 13.5 236.6 1.94 Clark Fork River below Warm Springs 9/17/2014 Field 11.91 200.3 9.26 414.3 13.4 269.1 1.99

Clark Fork River at Deer Lodge 7/2/2014 Field 10.01 -406.5 8.17 267.5 17.2 174.2 8.07 Clark Fork River at Deer Lodge 7/16/2014 Field 10.00 250.6 8.37 348.7 18.3 226.9 3.98 Clark Fork River at Deer Lodge 8/6/2014 Field 10.69 204.9 8.33 451.8 19.6 293.8 2.03 Clark Fork River at Deer Lodge 8/20/2014 Field 10.14 203.3 8.34 447.3 17.6 290.6 3.27 Clark Fork River at Deer Lodge 9/3/2014 Field 11.09 190.7 8.42 448.7 13.3 291.9 2.69 Clark Fork River at Deer Lodge 9/17/2014 Field 12.04 247.8 8.76 474.8 12.9 308.7 2.13

Clark Fork River above Little Blackfoot 7/2/2014 Field 9.68 -407.4 8.21 314.6 17.6 204.7 9.47 Clark Fork River above Little Blackfoot 7/16/2014 Field 11.02 196 8.44 374.8 18.4 243.8 2.96 Clark Fork River above Little Blackfoot 8/6/2014 Field 9.50 201.4 7.92 399.7 19.4 260 1.49 Clark Fork River above Little Blackfoot 8/20/2014 Field 11.76 194.9 8.29 462.7 17.7 301 2.8 Clark Fork River above Little Blackfoot 9/3/2014 Field 9.72 192.1 8.47 454.4 13.2 295.1 3.62 Clark Fork River above Little Blackfoot 9/17/2014 Field 11.28 216.6 8.46 474.9 12.8 308.7 2.79

Clark Fork River at Bonita 7/2/2014 Field 8.98 -406.1 8.13 350 17.3 227.5 11.3 Clark Fork River at Bonita 7/16/2014 Field 9.16 253.5 8.20 437.5 19.5 284.7 2.13 Clark Fork River at Bonita 8/6/2014 Field 8.70 244 8.24 545 19.3 354.2 1.99 Clark Fork River at Bonita 8/20/2014 Field 8.78 229.7 8.26 521 18.0 338.7 4.28 Clark Fork River at Bonita 9/3/2014 Field 9.10 239.7 8.21 494.1 14.7 321.1 5.09 Clark Fork River at Bonita 9/17/2014 Field 9.72 106.6 8.30 514 13.6 334.1 3.5

Clark Fork River above Missoula 7/2/2014 Field 9.10 -401.2 7.59 212.2 15.0 137.8 5.35 Clark Fork River above Missoula 7/16/2014 Field 8.73 240.6 8.00 249.7 17.2 162.5 2.67 Clark Fork River above Missoula 8/6/2014 Field 8.40 253 7.77 299.6 17.7 195 1.59

5 Dissolved Oxidation Specific Total oxygen reduction pH conductance Temperature, dissolved Turbidity Station Name Start Date Activity Type (mg/l) potential (mV) (s.u.) (uS/cm) water (deg C) solids (mg/l) (NTU) Clark Fork River above Missoula 8/20/2014 Field 8.25 243 8.05 302.7 17.1 196.9 1.51 Clark Fork River above Missoula 9/3/2014 Field 8.59 239.4 7.80 330 14.3 214.5 2.85 Clark Fork River above Missoula 9/17/2014 Field 9.34 235 7.68 346.9 12.5 225.6 2.34

Clark Fork River below Missoula 7/3/2014 Field 9.11 -442.9 8.07 207.9 16.3 135.2 5.34 Clark Fork River below Missoula 7/17/2014 Field 8.89 184.6 8.19 249.6 17.6 162.5 2.24 Clark Fork River below Missoula 8/7/2014 Field 8.86 203.7 8.15 269.2 18.2 174.8 2.12 Clark Fork River below Missoula 8/21/2014 Field 8.91 236 8.19 294.5 16.7 191.1 1.87 Clark Fork River below Missoula 9/4/2014 Field 10.88 226.4 8.11 324.4 13.0 210.6 2.51 Clark Fork River below Missoula 9/18/2014 Field 9.36 238.4 8.06 347.6 13.6 226.2 2.84

Clark Fork River at Huson 7/3/2014 Field 8.93 -410.2 7.67 137.6 17.0 89.7 5.13 Clark Fork River at Huson 7/17/2014 Field 8.85 179 7.94 177.2 18.9 115.1 2.26 Clark Fork River at Huson 8/1/2014 Field 8.72 195.8 7.72 234.1 21.4 152.1 1.54 Clark Fork River at Huson 8/21/2014 Field 9.34 238.3 8.21 258 18.1 167.7 1.61 Clark Fork River at Huson 8/30/2014 Field 9.55 193.4 8.32 275.6 18.2 179.4 1.79 Clark Fork River at Huson 9/18/2014 Field 8.13 268.2 8.08 306.7 14.3 199.6 2

Clark Fork River above Flathead 7/3/2014 Field 9.42 -381.7 7.89 136.4 17.4 88.4 5.71 Clark Fork River above Flathead 7/17/2014 Field 8.62 167.3 7.97 170.3 19.6 110.5 1.69 Clark Fork River above Flathead 8/1/2014 Field 8.09 98.6 8.07 219.6 20.3 143 1.31 Clark Fork River above Flathead 8/21/2014 Field 8.94 217.9 8.24 236.6 19.4 154 1.1 Clark Fork River above Flathead 8/30/2014 Field 8.17 210.5 8.22 257 17.9 167 1.91 Clark Fork River above Flathead 9/18/2014 Field 9.68 238.1 8.06 280.7 15.5 182.6 1.54

Clark Fork River below Thompson Falls 3/11/2014 Field 12.37 208 7.42 162 3.65 105 49.8 Clark Fork River below Thompson Falls 4/15/2014 Field 12.76 230.1 7.99 159 7.29 103 7.11 Clark Fork River below Thompson Falls 5/14/2014 Field 12.09 154.1 7.86 153 9.72 99 6.58 Clark Fork River below Thompson Falls 6/11/2014 Field 10.3 244.5 7.89 147 14.37 96 9.91 Clark Fork River below Thompson Falls 7/16/2014 Field 8.24 264.9 8.00 176 21.45 114 4.97 Clark Fork River below Thompson Falls 8/11/2014 Field 7.5 228.7 8.25 187 23.05 121 1.45

6 Dissolved Oxidation Specific Total oxygen reduction pH conductance Temperature, dissolved Turbidity Station Name Start Date Activity Type (mg/l) potential (mV) (s.u.) (uS/cm) water (deg C) solids (mg/l) (NTU) Clark Fork River below Thompson Falls 9/17/2014 Field 12.4 241.5 8.03 200 15.37 130 1.69 Clark Fork River below Thompson Falls 10/15/2014 Field 10.41 236.2 8.09 194 12.79 126 1.39 Clark Fork River below Thompson Falls 11/19/2014 Field 14.3 260.6 8.13 190 0.37 124 1.86

Clark Fork River at Noxon 3/11/2014 Field 13.54 213.6 8.00 184 0.98 120 3.81 Clark Fork River at Noxon 4/15/2014 Field 12.69 208.5 8.06 162 8.04 105 3.54 Clark Fork River at Noxon 5/14/2014 Field 11.98 139.9 7.75 136 9.42 88 5.70 Clark Fork River at Noxon 6/11/2014 Field 10.82 238.4 7.87 144 13.9 93 6.76 Clark Fork River at Noxon 7/16/2014 Field 8.31 234.2 7.98 165 20.54 107 2.46 Clark Fork River at Noxon 8/11/2014 Field 7.34 231.4 7.94 176 21.08 114 0.75 Clark Fork River at Noxon 9/17/2014 Field 10.33 230.8 7.73 193 16.55 126 1.15 Clark Fork River at Noxon 10/15/2014 Field 9.13 213.1 7.99 194 14.48 126 1.07 Clark Fork River at Noxon 11/19/2014 Field 10.9 239.9 8.19 186 7.22 121 1.39

Clark Fork River below Cabinet Gorge Dam 3/11/2014 Field 13.21 242.4 7.98 178 1.25 115 4.74 Clark Fork River below Cabinet Gorge Dam 4/15/2014 Field 12.89 211.5 7.99 167 8.03 108 2.32 Clark Fork River below Cabinet Gorge Dam 5/6/2014 Field 13.89 215.6 7.57 147 9.11 96 4.27 Clark Fork River below Cabinet Gorge Dam 5/14/2014 Field 12.3 98.7 7.77 135 9.74 88 5.90 Clark Fork River below Cabinet Gorge Dam 5/16/2014 Field 13.73 122.5 7.61 136 9.49 89 5.69 Clark Fork River below Cabinet Gorge Dam 5/23/2014 Field 13.45 222 7.55 124 11.19 80 8.32 Clark Fork River below Cabinet Gorge Dam 5/29/2014 Field 13.68 217.6 7.65 131 12.09 85 15.8 Clark Fork River below Cabinet Gorge Dam 6/6/2014 Field 12.77 161.5 7.66 144 12.8 93 9.92 Clark Fork River below Cabinet Gorge Dam 6/10/2014 Field 11.97 202.3 7.62 139 13.83 90 7.76 Clark Fork River below Cabinet Gorge Dam 6/11/2014 Field 11.84 231.4 7.80 142 13.82 92 6.24 Clark Fork River below Cabinet Gorge Dam 7/16/2014 Field 8.56 255.1 8.02 165 20.58 107 2.12 Clark Fork River below Cabinet Gorge Dam 8/11/2014 Field 8.21 214.2 8.08 175 20.33 114 0.90 Clark Fork River below Cabinet Gorge Dam 9/17/2014 Field 12.53 209.2 7.98 188 17.26 122 1.22 Clark Fork River below Cabinet Gorge Dam 10/15/2014 Field 9.31 212.2 7.83 194 14.26 126 1.00 Clark Fork River below Cabinet Gorge Dam 11/19/2014 Field 11.84 257.1 7.74 186 6.92 121 0.94

Flathead River 7/3/2014 Field 10.68 -381.6 8.02 163.5 17.6 106 5.1

7 Dissolved Oxidation Specific Total oxygen reduction pH conductance Temperature, dissolved Turbidity Station Name Start Date Activity Type (mg/l) potential (mV) (s.u.) (uS/cm) water (deg C) solids (mg/l) (NTU) Flathead River 7/17/2014 Field 9.63 169.1 8.27 166.7 23.3 108.5 3.35 Flathead River 7/31/2014 Field 8.58 167.7 8.60 0.3 22.3 0 1.31 Flathead River 8/1/2014 Field 9.12 130.5 8.33 167.3 22.4 108.5 1.33 Flathead River 8/21/2014 Field 9.28 228 8.42 162.5 21.8 106 1.03 Flathead River 8/30/2014 Field 7.59 207 8.37 176.5 19.2 114.4 0.995 Flathead River 9/18/2014 Field 10.12 250.2 8.39 180.5 17.2 117.7 1.37

8 2014 CFR-BASIN Chlorophyll-a Results

Averages for sample date in blue; Summer Mean in green; Summer mean exceedances in pink; Summer max exceedances in yellow

Ash-free Chlorophyll a Dry Weight Station Name Start Date Activity Type (mg/m2) (g/m2) Clark Fork River at Deer Lodge Summer Mean 221 Clark Fork River at Deer Lodge 8/3/2014 Date Average 280 95 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 697 295 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 264 101 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 47 25 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 41 17 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 79 26 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 82 28 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 106 38 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 93 35 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 128 50 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 162 55 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 156 56 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 819 291 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 175 54 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 256 62 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 229 56 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 320 172 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 1956 544 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 74 17 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 93 36 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 90 30 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 137 50 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 127 49 Clark Fork River at Deer Lodge 8/3/2014 Routine Sample 312 102 Clark Fork River at Deer Lodge 8/31/2014 Date Average 162 31 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 69 13 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 101 16 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 75 17 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 90 17 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 177 30 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 229 39 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 150 24 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 285 63 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 222 35 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 173 34 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 285 51 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 80 13 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 340 80 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 69 13 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 81 21 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 106 17 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 184 37 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 210 44 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 149 29 Clark Fork River at Deer Lodge 8/31/2014 Routine Sample 168 23

Clark Fork River above Little Blackfoot Summer Mean 91 Clark Fork River above Little Blackfoot 8/3/2014 Date Average 105 156 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 193 305 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 44 79 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 87 160 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 91 179 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 147 235 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 94 156

Ash-free Chlorophyll a Dry Weight Station Name Start Date Activity Type (mg/m2) (g/m2) Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 47 73 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 62 162 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 34 45 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 41 86 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 39 93 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 270 370 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 99 188 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 56 48 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 70 140 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 49 95 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 117 93 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 107 178 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 228 142 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 216 260 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 150 224 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 265 299 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 48 105 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 34 90 Clark Fork River above Little Blackfoot 8/3/2014 Routine Sample 49 97 Clark Fork River above Little Blackfoot 8/31/2014 Date Average 77 32 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 19 10 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 67 67 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 92 21 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 48 54 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 109 22 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 59 72 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 178 44 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 180 47 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 121 54 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample < 4 < 0.4 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 28 14 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 45 23 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 118 29 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 106 59 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 4 3.9 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 70 19 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 80 22 Clark Fork River above Little Blackfoot 8/31/2014 Routine Sample 64 11

Clark Fork River at Bonita Summer Mean 125 Clark Fork River at Bonita 8/3/2014 Date Average 151 123 Clark Fork River at Bonita 8/3/2014 Routine Sample 465 235 Clark Fork River at Bonita 8/3/2014 Routine Sample 25 7.4 Clark Fork River at Bonita 8/3/2014 Routine Sample 68 32 Clark Fork River at Bonita 8/3/2014 Routine Sample 107 57 Clark Fork River at Bonita 8/3/2014 Routine Sample 88 27 Clark Fork River at Bonita 8/3/2014 Routine Sample 82 47 Clark Fork River at Bonita 8/3/2014 Routine Sample 93 40 Clark Fork River at Bonita 8/3/2014 Routine Sample 48 45 Clark Fork River at Bonita 8/3/2014 Routine Sample 71 137 Clark Fork River at Bonita 8/3/2014 Routine Sample 108 100 Clark Fork River at Bonita 8/3/2014 Routine Sample 190 214 Clark Fork River at Bonita 8/3/2014 Routine Sample 529 240 Clark Fork River at Bonita 8/3/2014 Routine Sample 74 132 Clark Fork River at Bonita 8/3/2014 Routine Sample 46 170 Clark Fork River at Bonita 8/3/2014 Routine Sample < 4 < 0.4 Clark Fork River at Bonita 8/3/2014 Routine Sample 530 299 Clark Fork River at Bonita 8/3/2014 Routine Sample 161 275 Clark Fork River at Bonita 8/3/2014 Routine Sample 187 214 Clark Fork River at Bonita 8/3/2014 Routine Sample 310 213 Clark Fork River at Bonita 8/3/2014 Routine Sample 51 75

Ash-free Chlorophyll a Dry Weight Station Name Start Date Activity Type (mg/m2) (g/m2) Clark Fork River at Bonita 8/3/2014 Routine Sample 79 149 Clark Fork River at Bonita 8/3/2014 Routine Sample 9 1.9 Clark Fork River at Bonita 8/31/2014 Date Average 100 27 Clark Fork River at Bonita 8/31/2014 Routine Sample 94 21 Clark Fork River at Bonita 8/31/2014 Routine Sample 78 26 Clark Fork River at Bonita 8/31/2014 Routine Sample 136 57 Clark Fork River at Bonita 8/31/2014 Routine Sample 71 21 Clark Fork River at Bonita 8/31/2014 Routine Sample 163 28 Clark Fork River at Bonita 8/31/2014 Routine Sample 115 32 Clark Fork River at Bonita 8/31/2014 Routine Sample 54 20 Clark Fork River at Bonita 8/31/2014 Routine Sample 155 34 Clark Fork River at Bonita 8/31/2014 Routine Sample 34 5.0 Clark Fork River at Bonita 8/31/2014 Routine Sample 32 7.0 Clark Fork River at Bonita 8/31/2014 Routine Sample 35 6.2 Clark Fork River at Bonita 8/31/2014 Routine Sample 122 24 Clark Fork River at Bonita 8/31/2014 Routine Sample 224 87 Clark Fork River at Bonita 8/31/2014 Routine Sample 75 18 Clark Fork River at Bonita 8/31/2014 Routine Sample 80 23 Clark Fork River at Bonita 8/31/2014 Routine Sample 56 24 Clark Fork River at Bonita 8/31/2014 Routine Sample 172 31 Clark Fork River at Bonita 8/31/2014 Routine Sample 189 32 Clark Fork River at Bonita 8/31/2014 Routine Sample 43 13 Clark Fork River at Bonita 8/31/2014 Routine Sample 63 36

Clark Fork River above Missoula Summer Mean 92.5 Clark Fork River above Missoula 8/4/2014 Date Average 76 41 Clark Fork River above Missoula 8/4/2014 Routine Sample 13 5.8 Clark Fork River above Missoula 8/4/2014 Routine Sample 84 65 Clark Fork River above Missoula 8/4/2014 Routine Sample 34 14 Clark Fork River above Missoula 8/4/2014 Routine Sample 103 94 Clark Fork River above Missoula 8/4/2014 Routine Sample 24 17 Clark Fork River above Missoula 8/4/2014 Routine Sample 170 81 Clark Fork River above Missoula 8/4/2014 Routine Sample 269 67 Clark Fork River above Missoula 8/4/2014 Routine Sample 14 1.9 Clark Fork River above Missoula 8/4/2014 Routine Sample 32 15 Clark Fork River above Missoula 8/4/2014 Routine Sample 65 35 Clark Fork River above Missoula 8/4/2014 Routine Sample 139 70 Clark Fork River above Missoula 8/4/2014 Routine Sample 71 47 Clark Fork River above Missoula 8/4/2014 Routine Sample 63 29 Clark Fork River above Missoula 8/4/2014 Routine Sample 48 21 Clark Fork River above Missoula 8/4/2014 Routine Sample 74 52 Clark Fork River above Missoula 8/4/2014 Routine Sample 48 17 Clark Fork River above Missoula 8/4/2014 Routine Sample 90 72 Clark Fork River above Missoula 8/4/2014 Routine Sample 34 19 Clark Fork River above Missoula 8/4/2014 Routine Sample 64 56 Clark Fork River above Missoula 8/4/2014 Routine Sample 78 46 Clark Fork River above Missoula 8/29/2014 Date Average 109 31 Clark Fork River above Missoula 8/29/2014 Routine Sample 32 5.4 Clark Fork River above Missoula 8/29/2014 Routine Sample 90 30 Clark Fork River above Missoula 8/29/2014 Routine Sample 98 33 Clark Fork River above Missoula 8/29/2014 Routine Sample 148 58 Clark Fork River above Missoula 8/29/2014 Routine Sample 70 25 Clark Fork River above Missoula 8/29/2014 Routine Sample 113 22 Clark Fork River above Missoula 8/29/2014 Routine Sample 229 61 Clark Fork River above Missoula 8/29/2014 Routine Sample 68 16 Clark Fork River above Missoula 8/29/2014 Routine Sample 173 38 Clark Fork River above Missoula 8/29/2014 Routine Sample 218 58 Clark Fork River above Missoula 8/29/2014 Routine Sample 95 43 Clark Fork River above Missoula 8/29/2014 Routine Sample 137 39 Clark Fork River above Missoula 8/29/2014 Routine Sample 137 50 Clark Fork River above Missoula 8/29/2014 Routine Sample 75 19

Ash-free Chlorophyll a Dry Weight Station Name Start Date Activity Type (mg/m2) (g/m2) Clark Fork River above Missoula 8/29/2014 Routine Sample 90 20 Clark Fork River above Missoula 8/29/2014 Routine Sample 11 2.7 Clark Fork River above Missoula 8/29/2014 Routine Sample 205 40 Clark Fork River above Missoula 8/29/2014 Routine Sample 41 8.5 Clark Fork River above Missoula 8/29/2014 Routine Sample 67 30 Clark Fork River above Missoula 8/29/2014 Routine Sample 72 30

Clark Fork River below Missoula Summer Mean 82 Clark Fork River below Missoula 7/31/2014 Date Average 40 13 Clark Fork River below Missoula 7/31/2014 Routine Sample 24 6.2 Clark Fork River below Missoula 7/31/2014 Routine Sample 47 16 Clark Fork River below Missoula 7/31/2014 Routine Sample 50 21 Clark Fork River below Missoula 7/31/2014 Routine Sample 46 14 Clark Fork River below Missoula 7/31/2014 Routine Sample 60 24 Clark Fork River below Missoula 7/31/2014 Routine Sample 54 21 Clark Fork River below Missoula 7/31/2014 Routine Sample 48 15 Clark Fork River below Missoula 7/31/2014 Routine Sample 41 14 Clark Fork River below Missoula 7/31/2014 Routine Sample 51 19 Clark Fork River below Missoula 7/31/2014 Routine Sample 77 24 Clark Fork River below Missoula 7/31/2014 Routine Sample < 4 < 0.4 Clark Fork River below Missoula 7/31/2014 Routine Sample 32 9.3 Clark Fork River below Missoula 7/31/2014 Routine Sample < 4 < 0.4 Clark Fork River below Missoula 7/31/2014 Routine Sample 27 7.8 Clark Fork River below Missoula 7/31/2014 Routine Sample 29 8.9 Clark Fork River below Missoula 7/31/2014 Routine Sample 31 8.9 Clark Fork River below Missoula 7/31/2014 Routine Sample 42 16 Clark Fork River below Missoula 7/31/2014 Routine Sample 42 14 Clark Fork River below Missoula 7/31/2014 Routine Sample 52 16 Clark Fork River below Missoula 7/31/2014 Routine Sample 46 10 Clark Fork River below Missoula 9/1/2014 Date Average 124 20 Clark Fork River below Missoula 9/1/2014 Routine Sample 11 1.6 Clark Fork River below Missoula 9/1/2014 Routine Sample 117 18 Clark Fork River below Missoula 9/1/2014 Routine Sample 288 35 Clark Fork River below Missoula 9/1/2014 Routine Sample 139 21 Clark Fork River below Missoula 9/1/2014 Routine Sample 101 16 Clark Fork River below Missoula 9/1/2014 Routine Sample 107 17 Clark Fork River below Missoula 9/1/2014 Routine Sample 45 12 Clark Fork River below Missoula 9/1/2014 Routine Sample 166 29 Clark Fork River below Missoula 9/1/2014 Routine Sample 122 18 Clark Fork River below Missoula 9/1/2014 Routine Sample 184 26 Clark Fork River below Missoula 9/1/2014 Routine Sample 426 57 Clark Fork River below Missoula 9/1/2014 Routine Sample 40 6.2 Clark Fork River below Missoula 9/1/2014 Routine Sample 210 35 Clark Fork River below Missoula 9/1/2014 Routine Sample 90 19 Clark Fork River below Missoula 9/1/2014 Routine Sample 52 10 Clark Fork River below Missoula 9/1/2014 Routine Sample 31 8.1 Clark Fork River below Missoula 9/1/2014 Routine Sample 84 15 Clark Fork River below Missoula 9/1/2014 Routine Sample 179 28 Clark Fork River below Missoula 9/1/2014 Routine Sample 30 7.4 Clark Fork River below Missoula 9/1/2014 Routine Sample 51 11

Clark Fork River at Huson Summer Mean 22.5 Clark Fork River at Huson 8/1/2014 Date Average 20 5.5 Clark Fork River at Huson 8/1/2014 Routine Sample 22 7.4 Clark Fork River at Huson 8/1/2014 Routine Sample 37 7.4 Clark Fork River at Huson 8/1/2014 Routine Sample 47 10 Clark Fork River at Huson 8/1/2014 Routine Sample 27 7.0 Clark Fork River at Huson 8/1/2014 Routine Sample 25 10 Clark Fork River at Huson 8/1/2014 Routine Sample 15 3.9 Clark Fork River at Huson 8/1/2014 Routine Sample 27 2.7 Clark Fork River at Huson 8/1/2014 Routine Sample 12 5.9

Ash-free Chlorophyll a Dry Weight Station Name Start Date Activity Type (mg/m2) (g/m2) Clark Fork River at Huson 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River at Huson 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River at Huson 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River at Huson 8/1/2014 Routine Sample 16 6.2 Clark Fork River at Huson 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River at Huson 8/1/2014 Routine Sample 23 12 Clark Fork River at Huson 8/1/2014 Routine Sample < 4 0.4 Clark Fork River at Huson 8/1/2014 Routine Sample 39 12 Clark Fork River at Huson 8/1/2014 Routine Sample 17 8.5 Clark Fork River at Huson 8/1/2014 Routine Sample 27 5.0 Clark Fork River at Huson 8/1/2014 Routine Sample 27 6.6 Clark Fork River at Huson 8/1/2014 Routine Sample 22 3.9 Clark Fork River at Huson 8/30/2014 Date Average 25 11 Clark Fork River at Huson 8/30/2014 Routine Sample 31 7.4 Clark Fork River at Huson 8/30/2014 Routine Sample 27 10 Clark Fork River at Huson 8/30/2014 Routine Sample 21 11 Clark Fork River at Huson 8/30/2014 Routine Sample 22 8.5 Clark Fork River at Huson 8/30/2014 Routine Sample 22 7.8 Clark Fork River at Huson 8/30/2014 Routine Sample 19 8.1 Clark Fork River at Huson 8/30/2014 Routine Sample 37 16 Clark Fork River at Huson 8/30/2014 Routine Sample 15 8.5 Clark Fork River at Huson 8/30/2014 Routine Sample 16 12 Clark Fork River at Huson 8/30/2014 Routine Sample 42 28 Clark Fork River at Huson 8/30/2014 Routine Sample 22 12 Clark Fork River at Huson 8/30/2014 Routine Sample 24 5.8 Clark Fork River at Huson 8/30/2014 Routine Sample 17 10 Clark Fork River at Huson 8/30/2014 Routine Sample 31 10 Clark Fork River at Huson 8/30/2014 Routine Sample 25 6.6 Clark Fork River at Huson 8/30/2014 Routine Sample 27 5.0 Clark Fork River at Huson 8/30/2014 Routine Sample 25 19 Clark Fork River at Huson 8/30/2014 Routine Sample 19 5.0 Clark Fork River at Huson 8/30/2014 Routine Sample 42 17 Clark Fork River at Huson 8/30/2014 Routine Sample 25 14

Clark Fork River above Flathead Summer Mean 18 Clark Fork River above Flathead 8/1/2014 Date Average 19 8.7 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 0.8 Clark Fork River above Flathead 8/1/2014 Routine Sample 39 29 Clark Fork River above Flathead 8/1/2014 Routine Sample 50 22 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample 9 3.5 Clark Fork River above Flathead 8/1/2014 Routine Sample < 4 < 0.4 Clark Fork River above Flathead 8/1/2014 Routine Sample 10 3.1 Clark Fork River above Flathead 8/1/2014 Routine Sample 9 5.4 Clark Fork River above Flathead 8/1/2014 Routine Sample 44 23 Clark Fork River above Flathead 8/1/2014 Routine Sample 36 19 Clark Fork River above Flathead 8/1/2014 Routine Sample 39 20 Clark Fork River above Flathead 8/1/2014 Routine Sample 54 25 Clark Fork River above Flathead 8/1/2014 Routine Sample 69 22 Clark Fork River above Flathead 8/30/2014 Date Average 17 11 Clark Fork River above Flathead 8/30/2014 Routine Sample 8 3.5 Clark Fork River above Flathead 8/30/2014 Routine Sample 15 6.2 Clark Fork River above Flathead 8/30/2014 Routine Sample 31 14 Clark Fork River above Flathead 8/30/2014 Routine Sample 23 10

Ash-free Chlorophyll a Dry Weight Station Name Start Date Activity Type (mg/m2) (g/m2) Clark Fork River above Flathead 8/30/2014 Routine Sample 25 8.5 Clark Fork River above Flathead 8/30/2014 Routine Sample 22 8.5 Clark Fork River above Flathead 8/30/2014 Routine Sample 16 7.0 Clark Fork River above Flathead 8/30/2014 Routine Sample 18 7.0 Clark Fork River above Flathead 8/30/2014 Routine Sample 23 62 Clark Fork River above Flathead 8/30/2014 Routine Sample 10 8.5 Clark Fork River above Flathead 8/30/2014 Routine Sample 16 12 Clark Fork River above Flathead 8/30/2014 Routine Sample 9 5.0 Clark Fork River above Flathead 8/30/2014 Routine Sample 15 8.1 Clark Fork River above Flathead 8/30/2014 Routine Sample 13 28 Clark Fork River above Flathead 8/30/2014 Routine Sample 13 5.0 Clark Fork River above Flathead 8/30/2014 Routine Sample 12 3.9 Clark Fork River above Flathead 8/30/2014 Routine Sample 7 3.1 Clark Fork River above Flathead 8/30/2014 Routine Sample 15 6.6 Clark Fork River above Flathead 8/30/2014 Routine Sample 19 10 Clark Fork River above Flathead 8/30/2014 Routine Sample 26 13 Clark Fork River above Flathead 8/30/2014 Routine Sample 17 7.8

Flathead River Summer Mean 21 Flathead River 8/1/2014 Date Average 12 10 Flathead River 8/1/2014 Routine Sample 4 20 Flathead River 8/1/2014 Routine Sample 16 10 Flathead River 8/1/2014 Routine Sample 15 10 Flathead River 8/1/2014 Routine Sample < 4 < 0.4 Flathead River 8/1/2014 Routine Sample < 4 < 0.4 Flathead River 8/1/2014 Routine Sample 5 1.6 Flathead River 8/1/2014 Routine Sample < 4 < 0.4 Flathead River 8/1/2014 Routine Sample 4 1.2 Flathead River 8/1/2014 Routine Sample 4 1.6 Flathead River 8/1/2014 Routine Sample 29 26 Flathead River 8/1/2014 Routine Sample 35 29 Flathead River 8/1/2014 Routine Sample 11 7.8 Flathead River 8/1/2014 Routine Sample 22 20 Flathead River 8/30/2014 Date Average 30 16 Flathead River 8/30/2014 Routine Sample 4 2.3 Flathead River 8/30/2014 Routine Sample 12 7.8 Flathead River 8/30/2014 Routine Sample 24 10 Flathead River 8/30/2014 Routine Sample 27 11 Flathead River 8/30/2014 Routine Sample 42 10 Flathead River 8/30/2014 Routine Sample 49 35 Flathead River 8/30/2014 Routine Sample 47 21 Flathead River 8/30/2014 Routine Sample 38 17 Flathead River 8/30/2014 Routine Sample 27 26 Flathead River 8/30/2014 Routine Sample 68 40 Flathead River 8/30/2014 Routine Sample 81 46 Flathead River 8/30/2014 Routine Sample 23 10 Flathead River 8/30/2014 Routine Sample 22 20 Flathead River 8/30/2014 Routine Sample 6 2.7 Flathead River 8/30/2014 Routine Sample 7 3.1 Flathead River 8/30/2014 Routine Sample 12 5.4 Flathead River 8/30/2014 Routine Sample 55 31 Flathead River 8/30/2014 Routine Sample 14 5.0 Flathead River 8/30/2014 Routine Sample 31 13 Flathead River 8/30/2014 Routine Sample 21 12

TECHNICAL MEMORANDUM

TO: MR. JOE DOSSANTOS, AVISTA CORPORATION

FROM: LUKE OSBORNE, P.E., HYDROSOLUTIONS INC

DATE: MAY 7, 2015

SUBJECT: ESTIMATE OF 2014 NUTRIENT LOADING FROM CLARK FORK RIVER INTO LAKE PEND OREILLE

Introduction

HydroSolutions Inc (HydroSolutions) completed this technical memorandum under contract with Avista Corporation (Avista) as part of their 2014 annual water quality monitoring program. Clark Fork River water quality monitoring for nutrient concentrations completed by Avista is used to assess annual nutrient loading of the Clark Fork River to Lake Pend Oreille. This memorandum evaluates nutrient loading estimates to nutrient targets established in the 2002 Montana and Idaho Nutrient Load Agreement. Avista conducts monthly water quality monitoring from March through November at three Lower Clark Fork River monitoring stations, and peak flow monitoring at one monitoring station. Nine water quality sample sets are collected during monthly monitoring at all three monitoring stations. Peak flow monitoring includes collection of six water quality sample sets at the furthest downstream monthly monitoring station, Clark Fork River below Cabinet Gorge Dam (CFR-30), near the Montana-Idaho border. Peak flow monitoring generally occurs during the rising limb and peak flow of the annual hydrograph (typically May and June). Surface water samples collected at CFR-30 for Avista’s monitoring program are analyzed for total phosphorus (TP) and total nitrogen (TN) and used to estimate nutrient loading to Lake Pend Oreille from the Clark Fork River. Montana Department of Environmental Quality (DEQ) completeed all quality assurance (QA) review of the water quality data prior to this evaluation.

Montana and Idaho Border Nutrient Load Agreement

The Montana and Idaho Border Nutrient Load Memorandum of Agreement (Border Agreement) was established in 2002. Nutrient targets established in the Border Agreement were developed to maintain water quality in the open waters of Lake Pend Oreille from the mouth of the Clark Fork River to the Long Bridge (Highway 95). The Border Agreement and the Montana and Idaho Border Nutrient Load Agreement Technical Guidance (Tri-State Water Quality Council 2001) are available on the Montana DEQ website at: http://www.deq.mt.gov/wqinfo/OtherWQLinks.mcpx. Nutrient targets are outlined in section VII of the Border Agreement as follows:

Billings Office Helena Office PO Box 80866 PO Box 1779 Billings, MT 59108-0866 Helena, MT 59624 Phone: (406) 655-9555 Phone: (406) 443-6169 Fax: (406) 655-0575 Fax: (406) 443-6385 Avista Corporation May 7, 2015 Clark Fork River Nutrient Loading 2014 Page 2

• An area-weighted euphotic-zone average concentration of 7.3 μg/L total phosphorus for Lake Pend Oreille, • Total loading to Lake Pend Oreille of 328,651 kilograms per year (kg/year) total phosphorus, • 259,500 kg/year total phosphorus from Montana (as measured at Clark Fork River below Cabinet Gorge Dam), • 69,151 kg/year total phosphorus from Lake Pend Oreille watershed in Idaho, • Greater than 15:1 total nitrogen to total phosphorus ratio. The Border Agreement establishes short-term and long-term exceedances of the established nutrient targets. As stated in the Border Agreement, an exceedance of the target exists when either of the following conditions are documented: (a) A short-term exceedance of the targets (three consecutive years of total phosphorus load increases at the border that are above the targets by greater than 10%). (b) A long-term exceedance of the targets (a ten year average total phosphorus concentration in the lake greater than 7.3 μg/L). In support of the Border Agreement, and in coordination with Montana DEQ, this memorandum provides estimates of 2014 annual nutrient loads from the Clark Fork River. The annual TP load is estimated from the Clark Fork River monitoring station CFR-30. The estimated annual TP load is evaluated against the Border Agreement’s nutrient load target apportioned to the Clark Fork River of 259,500 kg/year, and for short term exceedance of this target.

Nutrient Loading Estimation Method

Consistent with previous analyses, Clark Fork River nutrient loading (TP and TN) into Lake Pend Oreille was evaluated using the U.S. Army Corps of Engineers (USACE) FLUX32 Load Estimation Software model (version 3.10). The FLUX32 model is one of three USACE models that comprise the BATHTUB Eutrophication model (Walker 1999). The model uses grab-sample nutrient concentrations, corresponding discharge measurements, and complete discharge records to calculate annual nutrient loading. The FLUX32 model provides six methods to synthesize the discharge-nutrient concentration relationship from individual sample records and impute them onto the entire flow record. Method 6, Regression Applied to Individual Flows, as described in the Technical Guidance document (Tri-State Water Quality Council 2001), has been used in previous annual and five year trend reports (Tri-State Water Quality Council 2009), and is used in this evaluation to maintain consistency. Method 6 is generally preferred over the other regression-based methods when the discharge-nutrient concentration relationship is well defined. Method 6, Regression Applied to Individual Flows, is defined by Walker (1999) and shown in the following equation:

2 W = exp a + (b +1)ln(Q )+ SE 6 ∑j [ j 2 ]

Where:

HydroSolutions Inc Avista Corporation May 7, 2015 Clark Fork River Nutrient Loading 2014 Page 3

W6 = estimated mean flux over N days, method 6 (kg/year)

c = measured concentration in sample in milligrams per cubic meter (mg/m3) q = measured flow during sample

a = intercept of ln(c)versus ln(q) regression

b = slope of ln(c)versus ln(q)regression

3 Q j = mean flow on day j in cubic hectometers per year (hm /year)

= sum over N days in daily flow record ∑ j

SE = Standard error of estimate for ln(c)versus ln(q)regression

For the loading analysis, nutrient concentrations were converted from µg/L to milligrams per cubic meter (mg/m3) and discharge values were converted from cfs to cubic hectometers per year (hm3/year). The FLUX32 program outputs of 2014 TP and TN loading are provided in Attachment 1.

To be consistent with previous nutrient loading analysis, nutrient loads were estimated using the record of mean daily discharge from U.S. Geological Survey (USGS) station 12392000, Clark Fork River at Whitehorse Rapids. This station is located downstream of Cabinet Gorge Dam and though it is no longer operated, the USGS maintains flow annual discharge records. Flow at this station is now calculated from the sum of measured flow at USGS station 12391950, Clark Fork River below Cabinet Gorge dam and 600 cfs groundwater inflow derived from seepage estimation around the dam (USGS 2015).

To improve loading estimates the model stratified loading regressions by the discharge hydrograph. The FLUX32 model develops separate regression equations for individual stratified discharge regimes. As defined by the model, the three separate stratum used include: flow less than one-half of the mean, medium flow, and flow greater than two times the mean. For each stratum, a regression equation is applied individually to each corresponding flow value. The sum of daily loads provides the annual estimate.

Nutrient Loading Results

Results of the loading estimated for 2014 and the previous two years is presented in Table 1. In 2014 the estimated TP load exceeded the allocated target load of 259,500 kilograms per year by 0.4 percent. Since 1998 the estimated TP load has exceeded the allocated target load five times. All of the exceedances have occurred in the last eight years: in 2006, 2008, 2011, 2012, and 2014. Of those exceedances only estimated TP loads in 2011 and 2012 were greater than 110 percent of the target load as defined in the Border Agreement in evaluating short term exceedances. Although no targets are established for TN loading to Lake Pend Oreille, they are also presented in Table 1.

HydroSolutions Inc Avista Corporation May 7, 2015 Clark Fork River Nutrient Loading 2014 Page 4

Table 1. Estimated Lake Pend Oreille Nutrient Loads from Clark Fork River 2012 to 2014 Daily Mean Flow rate Inflow Volume TP Loading TN Loading

Year 3 ac-ft x CFS % of Average hm Kg x 1000 lbs x 1000 Kg x 1000 lbs x 1000 1000

2012 26,219 119% 23,481 19,036 312.0 687.8 3,966 8,743

2013 19,535 89% 17,447 14,144 148.9 328.2 2,279 5,025

2014 25,598 116% 22,799 18,483 260.5 574.3 3,720 8,200 Notes: CFS - cubic feet per second lbs -- pound mass TP - Total Phosphorus hm3 - cubic hectometer Kg – Kilogram TN - Total Nitrogen ac-ft - acre feet -Average of mean daily flow rate at USGS gaging station 12392000 Clark Fork at Whitehorse Rapids near Cabinet Idaho for 1929-2014 approved daily mean data. -Nutrient load of 259,500 kilograms per year TP is allocated in The Montana and Idaho Border Nutrient Load Memorandum of Agreement for Clark Fork River nutrient contribution to Lake Pend Oreille

TP and TN loading to Lake Pend Oreille from the Clark Fork River from 1998 to 2014 are presented in Figures 1 and 2.

600 160%

140% 500 2014) 120% 400 100%

300 80%

Target Load 259,500 Kg 60% 200 40% 100 PhosphorusLoad x (Kg 1,000) 20% Inflow Percent of Average - (1929 Average of Percent Inflow 0 0% 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Phosphorus Load Inflow

Figure 1. Chart of Estimated Total Phosphorus Loading from the Clark Fork River 1998 to 2014, Annual Inflow as Percent of Average at USGS Gaging Station 12392000 Clark Fork at Whitehorse Rapids, and Montana-Idaho Nutrient Border Agreement Clark Fork River Allocated Annual Target Load.

HydroSolutions Inc Avista Corporation May 7, 2015 Clark Fork River Nutrient Loading 2014 Page 5

6000 160%

140%

5000 2014)

120%

4000 100%

3000 80%

60% 2000

40% NitrogenLoad (Kg x 1,000) 1000 20% Inflow Percent of Average - (1929 Average of Percent Inflow 0 0% 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Nitrogen Load Inflow

Figure 2. Chart of Estimated Total Nitrogen Loading from the Clark Fork River 1998 to 2014 and Annual Inflow as Percent of Average at USGS Gaging Station 12392000 Clark Fork at Whitehorse Rapids.

Conclusions

Nutrient loading of TP and TN from the Clark Fork River to Lake Pend Oreille varies year to year and is in general, proportional to the volume of inflow from the watershed. In years when Clark Fork River flow from Montana is in excess of the annual average daily discharge, the TP load exceeds the allocated target load of 259,500 kilograms per year of the Border Agreement. The estimated TP load has exceeded the allocated target load five times since 1998. In 2014 the average daily flow was 116 percent of the long term average and the estimated TP load was 260,519 Kg, or 0.4 percent above the allocated target load. Estimated TP and TN loading in 2014 were consistent with the average daily flow for the year. Similar to the average daily flow trends, estimated TP and TN loading in 2014 was more than 2013 loading levels, but less than 2012 loading levels. Estimated TP loads in 2012 to 2014 are less than 110 percent of the target load. Based on this assessment there is no short term TP load exceedance in the past three years or any previous consecutive three year period since 1998. Attachment 1 FLUX32 program outputs of 2014 TP and TN loading

HydroSolutions Inc Avista Corporation May 7, 2015 Clark Fork River Nutrient Loading 2014 Page 6

References

Tri-State Water Quality Council. 2001. "Montana and Idaho Border Nutrient Load Agreement Technical Guidance." Montana DEQ Water Quality Planning Bureau Other Water Quality Links. January. Accessed May 6, 2014. http://www.deq.mt.gov/wqinfo/pdf/TechGuidanceFinal.pdf.

Tri-State Water Quality Council. 2009. Water Quality Status and Trends in the Clark Fork-Pend Oreille Watershed: Time Trends Analysis for the 1984-2007 Period. Helena: PBS&J.

U.S. General Services Administration. 2012. Preliminary Engineering Report Infrastructure Piegan Port of Entry, Piegan, Montana. Helena, MT: Robert Peccia and Associates.

USGS. 2015. USGS 12392000 Clark Fork at Whitehorse Rapids near Cabinet, Idaho. April 8. Accessed April 30, 2015. http://waterdata.usgs.gov/nwis/dv?referred_module=sw&site_no=12392000.

Walker, W.W. 1999. Simplified Procedures for Eutrophication Assessment and Predicion: User Manual. Updated April, Instruction Report W-96-2. Vicksburg: U.S. Army Corps of Engineers Waterways Experimentation Station.

HydroSolutions Inc

ATTACHMENT 1

FLUX32 Program Outputs of 2014 TP and TN Loading

HydroSolutions Inc FLOW AND LOAD SUMMARIES FOR TotalPhosphorus(ug/L)

Method: C/Q Reg3(daily) (6) DISTRIBUTION OF SAMPLES VS. DAILY FLOWS Daily Flow Smpl FlowTotalPhosphorus(ug/L) Flux** SLOPE Stratum Flows Smpls Evnts Vol % (CFS) (CFS) (µg/L) (kg/y) LgC/LgQ R² p > C/Q 1 Flow < 1/2 Me 114 3 3 12.3 10028.77 11033.33 6.8 60606 -3.176 0.62 0.4238 2 Medium Flow 189 5 5 43.9 21649.89 31880 10.18 173904 0.5549 0.75 0.0556 3 Flow > 2x Mea 61 7 7 43.8 66924.59 68200 14.943 902489 1.092 0.79 0.0079 Overall 364 15 15 100.0 25597.56 44660 11.727 260519 0.4612 0.83 0.0000

STRATUM BOUNDARIES(CFS) ------STRATUM LOWER LIMIT UPPER LIMIT Flow < 1/2 Mean 0 12798.8 Medium Flow 12798.8 51195.1 Stratum 3 51195.1 91302.7

------

DAILY FLOW STATISTICS Daily Flow Duration 364 Days = 0.997 Years Daily Mean Flow Rate 25597.60 (CFS) Daily Total Flow Volume 22799.00 (Mega m³) Daily Flow Date Range 01/01/2014 to 12/31/2014 Samples Date Range 03/11/2014 to 11/19/2014

LOAD ESTIMATES FOR TotalPhosphorus(ug/L) Flw Wgted Method Mass(kg) Flux(kg/y)** Flux Variance Conc.(µg/L) C.V. 1 Average Load 341738 342911 3.4012919E9 15 0.170 2 Flw Wghted Conc. 284618 285595 7.2918364E8 12.5 0.095 3 Flw Wghted IJC. 287972 288961 8.547306E8 12.6 0.101 4 C/Q Reg1 262899 263802 6.655642E8 11.5 0.098 5 C/Q Reg2(VarAdj) 264753 265662 4.7348783E8 11.6 0.082 6 C/Q Reg3(daily) 259627 260519 4.2894257E8 11.4 0.079 8 Time Series* 258318 259205 N/A 11.3 N/A

------*Time series estimates use residual interpolation. Maximum Interpolation Gap is set at 15.00 days ** Flow duration includes a fractional year; units of Flux/y may mislead. FLOW AND LOAD SUMMARIES FOR TotalNitrogen(ug/L)

Method: C/Q Reg3(daily) (6) DISTRIBUTION OF SAMPLES VS. DAILY FLOWS Daily Flow Smpl FlowTotalNitrogen(ug/L) Flux** SLOPE Stratum Flows Smpls Evnts Vol % (CFS) (CFS) (µg/L) (kg/y) LgC/LgQ R² p > C/Q 1 Flow < 1/2 Me 114 3 3 12.3 10028.77 11033.33 115.33 1040592 0.5535 0.30 0.6287 2 Medium Flow 190 5 5 44.5 21807 31880 149.2 2977329 -0.04694 0.01 0.8777 3 Flow > 2x Mea 60 7 7 43.3 67181.67 68200 182.57 11160169 0.9464 0.41 0.1175 Overall 364 15 15 100.0 25597.56 44660 158 3719588 0.2291 0.41 0.0103

STRATUM BOUNDARIES(CFS) ------STRATUM LOWER LIMIT UPPER LIMIT Flow < 1/2 Mean 0 12889.7 Medium Flow 12889.7 51559 Stratum 3 51559 91750.3

------

LOAD ESTIMATES FOR TotalNitrogen(ug/L) Flw Wgted Method Mass(kg) Flux(kg/y)** Flux Variance Conc.(µg/L) C.V. 1 Average Load 4446318 4461587 3.0910566E11 195 0.125 2 Flw Wghted Conc. 3687105 3699767 6.511735E10 162 0.069 3 Flw Wghted IJC. 3699327 3712031 6.5720037E10 162 0.069 4 C/Q Reg1 3680397 3693035 9.0296665E10 161 0.081 5 C/Q Reg2(VarAdj) 3666154 3678744 1.0402965E11 161 0.088 6 C/Q Reg3(daily) 3706859 3719588 1.0460377E11 163 0.087 8 Time Series* 3671382 3683990 N/A 161 N/A

------*Time series estimates use residual interpolation. Maximum Interpolation Gap is set at 15.00 days ** Flow duration includes a fractional year; units of Flux/y may mislead.