# Spokane River Dissolved Metals Total Maximum Daily Load

Submittal Report

May 1999 Publication No. 99-49-WQAdams

Asotin Benton Chelan Clallam

Clark Columbia

Cowlitz Douglas Ferry

Franklin Garfield Grant Grays

Harbor Island

Jefferson

King K i t s a p

Kittitas

Klickitat Lewis Lincoln

Mason Okanogan

Pacific Pend

Oreille

Pierce San Juan

Skagit

Skamania

Snohomish

Spokane Stevens

Thurston

Wahkiakum
Walla

Walla Whatcom

Whitman

Yakima Northwest
425-649-7000

Southwest

360-407-6300 Eastern
509-329-3400 Central

509-575-2490 Headquarters (Lacey) 360-407-6000 TTY (for the speech and hearing impaired) statewide is 711 or 1-800-833-6388

Regional

Office

location

Spokane

Yakima Lacey Bellevue For additional copies of this report, contact:

Department of Ecology

Publications

P.O. Box 47600 Olympia, WA 98504-7600 Telephone: (360) 407-7472

The Department of Ecology is an equal opportunity agency and does not discriminate on the basis of race, creed, color, disability, age, religi on, national origin, sex, marital status, disabled veteran's status, Vietnam Era vetera n's status, or sexual orientation.

If you need this publication in an alternate format, please contact us at 509-329-3503 or TTY (for the speech and hearing impaired) at 711 or 1-800-833-6388.

# Spokane River Dissolved Metals Total Maximum Daily Load

Submittal Report

by

Steve Butkus

Ken Merrill

Washington State Department of Ecology Water Quality Program

Post Office Box 47600 Olympia, Washington 98504-7600

May 1999 Publication No. 99-49-WQSpokane River Metals TMDL Page i 

# Table of Contents

List of Figures............................................................................................ii

List of Tables.............................................................................................ii

Introduction...............................................................................................1

Background...............................................................................................3

Applicable Criteria.......................................................................................4

Water Quality Impairments.............................................................................6

Seasonal Variation.......................................................................................6

Modeling Approach.....................................................................................8

Loading Capacity ........................................................................................8

Load and Waste Load Allocations.....................................................................9

Margin of Safety.........................................................................................10

Summary Implementation Strategy...................................................................10

References Cited.........................................................................................12

Figures.....................................................................................................13

Appendix A - Public Participation Materials

Appendix B - Responses to Comments Recieved

Appendix B - Quality Assurance Project Plan

Appendix C - Technical Report: Pelletier, G. and K. Merrill. 1998. "Cadmium, Lead, and Zinc in the Spokane River - Recommendations fo r Total Maximum Daily Loads and Waste Load Allocations", Publication No. 98-329, Washington Department of Ecology, Olympia, WA.Spokane River Metals TMDL Page ii 

# List of Figures

Figure 1. Spokane River Drainage System Map..................................................13



# List of Tables

Table 1. Spokane River 1998 Sec tion 303(d) Listed Segments...................................6

Table 2. Seasonal Statistics of the Spoka ne River Total Recoverable Metals at Washington-Idaho Border ...............................................................7

Table 3

. Seasonal Statistics of th e Spokane River Hardness......................................7Spokane River Metals TMDL Page 1 

# Introduction

Section 303(d) of the federal Cl ean Water Act mandates that the State establish Total Maximum Daily Loads (TMDLs) for surface waters that do not meet standards after application of technology-based pollution controls. The U.S. Environmental Protection Agency (EPA) has established regulations (40 CFR 130) and de veloped guidance (EPA, 1991) for establishing

TMDLs.

Under the Clean Water Act, every state has its ow n water quality standards designed to protect, restore, and preserve water qual ity. Water quality standards cons ist of designated uses, such as cold water biota and drinking water supply, and cr iteria, usually numeric criteria, to achieve those uses. When a lake, river or stream fails to meet water quality standa rds after application of required technology-based controls, the Clean Water Act requires th at the state place the water body on a list of "impaired" water bodies and to prepare an analysis called a Total Maximum Daily Load (TMDL)

.

The goal of a TMDL is to ensure the impaired water will attain water quality standards. A TMDL includes a written, quantitative assessment of water quality problem s and of the pollutant sources that cause the problem. The TMDL dete rmines the amount of a given pollutant which can be discharged to the water body a nd still meet standards, called the loading capacity, and allocates that load among the various sources. If the pollutant comes from a discrete source (referred to as a point source ) such as an industrial f acility’s discharge pipe, that facility’s share of the loading capacity is called a wasteload allocation . If it comes from a diffuse source (referred to as a nonpoint source ) such as a farm, that facility’s share is called a load allocation

.

The TMDL must also consider seasonal variations and include a margin of safety that takes into account any lack of knowledge about the causes of the water quality pr oblem or its loading capacity. The sum of the individual allocations and th e margin of safety must be equal to or less than the loading capacity.

The Washington State Department of Ecology (Eco logy) is establishing a Total Maximum Daily Load (TMDL) for the Spokane River for dissolv ed cadmium, lead, and zinc. This TMDL will address impairments due to potentia l toxic effects on the five segmen ts of the river listed in the 1988 Section 303(d) list of impaired surface waters.Spokane River Metals TMDL Page 2 The five elements of the Spokane River Dissolved Metals TMDL as required by the Clean Water

Act are :



### Loading Capacity
In the case of dissolved metals in the Spokane River, a concentration measure is appropriate because the relationship between the effluent-b ased criterion and the receiving water quality

holds for all effluent flow rate s and critical conditions in th e Spokane River. The proposed

concentration-based allocations assure that the in-river concentration of the metals of concern will always be further below the aquatic toxic ity criterion downstream of each discharge than

was present upstream.



### Wasteload Allocation
The Spokane River dissolved metals waste load a llocation is based on the most restrictive permit limits derived by either meeting aquatic life toxicity criteria at effluent hardness at the end-ofpipe, or based on maintaining exis ting concentrations of metals in effluent using performancebased limits with an added 10 percent compliance buffer. Whichever method results in the lower limit will be selected for the permit limit and established as the wasteload allocation. A minimum of ten representative low-level metals analyses will be required of dischargers where adequate metals data does not exist to develop performance-based limits.



### Load Allocations
The load allocation is the concentration required to meet the chronic criterion at the outlet of Lake Coeur d'Alene. However, the concentr ation-based wasteload allocation approach will assure compliance with Washington State water qua lity standards even if the Spokane River only meets the standards at the Washington-Idaho border.



### Margin of Safety
Numerous conservative assumptions were made in model development to provide an inherent margin of safety. Extreme values of either 90 th or 10 th percentile values were used to estimate

critical variables in the model application. In the worst-case scenario, the highest allowable

effluent concentration as derive d from the end-of-pipe, aquatic life criteria met hod will assure that downstream metals concentrations will be further below the aquatic life criteria than present upstream of each discharge. It is anticipated that wasteload allocations using the performancebased method will, in many cases, be much less th an allocations using the end-of-pipe, aquatic life criteria method, and ther efore will provide a great er margin of safety.



### Seasonal Variation
Water quality data on metals and hardness coll ected in the Spokane River show seasonal variation at the Washington-Idaho border. The meta ls data show increasing trends as river flows increase. Significant variation in hardness al so occurs during the lower river flows when groundwater inflow significantly affects river ha rdness moving progressively downstream in the Spokane Valley. The modeling approach used the conservative approach for critical conditions

when river hardness is low.Spokane River Metals TMDL Page 3 

# Background

Geographic Setting

The source of the Spokane River is Lake Coeur d' Alene located in Idaho (Figure 1). The river flows in a westerly direction from the lake, across the state boundary line, to the city of Spokane. From Spokane, the river flows in a northwesterly direction to its conflu ence with the Columbia River. The Spokane River is approximatel y 111 miles long with a watershed covering 6,580 square miles. Major tributar ies to the Spokane River include the Little Spokane River and Hangman (Latah) Creek. There are six hydroele ctric dams located on the Spokane River.

Forested lands comprise a majority of the land us e in Washington (55%), with agriculture (33%), urban (6%) and rangeland (3%) following in areas c overed. Agricultural lands lie mainly in the Lower Spokane River, Little Spokane River, and Hangman Creek watersheds. Urban land use occurs mainly in the Middle Spokane River waters hed, primarily due to th e location of the City of Spokane. The population of the greater Spokane is 400,000. Other urban areas include Cheney (population 7,700), Medical Lake (popula tion 3,700), Deer Park (population 2,300), and Airway Heights (population 2,000). The Spokane I ndian Tribe's reservation is located in the lower river watershed, covering 155, 000 acres of land (Knight, 1998).

The Spokane River has a complex geological hi story (Crosby et al., 1971). The basin is composed of highly porous, poorly sorted glacial deposits. The upper and lower river substrate is composed of granitic rock cobble. From Ri ver mile 90 to 85 the substrate is composed of

rocks and boulders. The river do es not exhibit typical riffle-p ool morphology (Bailey and Saltes, 1982). Below the river lies the Spokane-Rathdrum Aquifer, which is the sole source of drinking water for the region.

The climate in the watershed is temperate. The region lies on the edge of a rain shadow created by the Cascade Mountain Range. Annual rainfall va ries from 14 inches in the lower watershed to 35 inches in the upper watershe d. The precipitation near the City of Spokane is 17 inches per year. The average temperature range is 21°F to 85°F, with extreme temperatures from below minus 30°F to over 100°F (Knight, 1998).

The annual average flow in the Spokane River is approximately 6,300 cfs. The lowest 7-day average flow with a 10-year recurrence at the up stream end near Post Falls is approximately 187 cubic feet per second (cfs). The highest 7-da y average flow with a 10-year recurrence is approximately 36,000 cfs. Substantial inflow s of groundwater enter the river beginning downstream from the Liberty Lake outfall. Th ese groundwater inflows si gnificantly increase the river flow rate, especially when surface water flow s are low. The total net aquifer inflows range between 500 to 800 cfs. For comparison, the combined effluent flow from all permitted discharges is about 128 cfs (Pelletier and Merrill, 1998).Spokane River Metals TMDL Page 4 

## Description of Pollutant Sources

Seven wastewater treatment facili ties legally discharge to the ri ver. In Idaho, EPA permits the following discharges (proceeding downstream from the river source):

• City of Coeur d'Alene Advanced Wastewater Treatment Plant

• Hayden Area Regional Sewer Board Publicly-owned Treatment Works

• City of Post Falls Publicly-owned Treatment Works Continuing downstream, Ecology permits discharges from:

• Liberty Lake Publicly-owned Treatment Works

• Kaiser Aluminum Industrial Wastewater Treatment Plant

• Inland Empire Paper Company Industrial Wastewater Treatment Plant

• City of Spokane Advanced Wastewater Treatment Plant



# Applicable Criteria

Description of the Applicable Water Quality Standards and Numeric Water Quality Target

Within The State of Washington, water quality standards are published pursuant to Chapter 90.48 of the Revised Code of Washington (RCW). Authority to adopt rules, regulations, and standards as are necessary to pr otect the environment is vested with the Department of Ecology. Under the federal Clean Water Act, the EPA Re gional Administrator must approve the water quality standards adopted by the State (Section 303(c)(3)). Through adoption of these water quality standards, Washington has designated certai n characteristic uses to be protected and the criteria necessary to protect these uses [Was hington Administrative C ode (WAC), Chapter 173- 201A). These standards were la st adopted in November 1997.Spokane River Metals TMDL Page 5 This TMDL is designed to address impairments of characteristic uses ca used by toxic effects of metals. The characteristic uses designated fo r protection in the Spokane River are as follows:

"Characteristic uses. Characteristic uses sha ll include, but not be li mited to, the following:

(i) Water supply (domestic, industrial, agricultural).

(ii) Stock watering.

(iii) Fish and shellfish:

Salmonid migration, rearing, spawning, and harvesting.

Other fish migration, rear ing, spawning, and harvesting.

Clam and mussel rearing, spawning, and harvesting.

Crayfish rearing, spawning, and harvesting.

(iv) Wildlife habitat.

(v) Recreation (primary contact recreati on, sport fishing, boating, and aesthetic enjoyment).

(vi) Commerce and navigation."

[WAC 173-201A-030(2)]

The water quality standards describe criteria for metals for the protection of characteristic uses. The Spokane River TMDL establishes allocations for cadmium, lead, and zinc. The chronic and acute criteria of these metals apply to the dissolv ed form and are calculated using water hardness (in mg/L as CaCO 3 ) based on the following equations:

Dissolved Cadmium

Chronic < (1.101672-((ln(hardness))*(0.041838 )))*EXP(0.7852*(ln(ha rdness))-3.49)

Acute < (1.136672-((ln(hardness ))*(0.041838)))*EXP (1.128*(ln(hardness))-3.828)

Dissolved Lead

Chronic < (1.46203-((ln(hardness) )*(0.145712)))*EXP(1.273*( ln(hardness))-4.705)

Acute < (1.46203-((ln(hardness))*(0.145712 )))*EXP(1.273*(ln( hardness))-1.46)

Dissolved Zinc

Chronic < 0.986*EXP(0.8473*(ln (hardness))+0.7614)

Acute < 0.978*EXP(0.84 73*(ln(hardness))+0.8604)

[WAC 173-201A-040]Spokane River Metals TMDL Page 6 

# Water Quality Impairments

As a result of measurements made that show criteria are exceeded, the Spokane River (representing 18 segments) is included on Washington's 1998 Sec tion 303(d) list (Table 1).

Table 1

. Spokane River 1998 Section 303(d) Listed Segments

Listed Parameter Segment Location (Township-Range-Section)

Cadmium 25N-46E-06
Lead 25N-42E-14, 26N-42E-20, 25N-46E-06
Zinc 25N-42E-14, 26N-42E-20, 26N -42E-33, 25N-44E-03, 25N-46E-06
PCBs* 27N-40E-22, 26N-42E-05, 26N-42E-07, 28N-37E-33

Chromium* 25N-42E-04

Arsenic* 25N-46E-06 Sediment Bioassay* 28N-37E-33, 25N-43E-01 Dissolved Oxygen* 25N-44E-06, 25N-46E-06 pH* 28N-36E-20 Temperature* 28N-36E-20 Total Phosphorus* 26N-42E-07

• not addressed in this TMDL



# Seasonal Variation

Data on total recoverable cadmium, lead, zi nc, and hardness collect ed by Ecology at the Washington-Idaho border between 1991 and 1998 we re compiled and descriptive statistics generated (Table 2). Sufficient dissolved metals data of which the TMDL is based were not available to compute similar statistics. Howe ver, similar patterns are observed with total recoverable metals and are used here only for pr esentation. Additional information regarding the relationship of dissolved metals with flows is presented in Pelletier and Me rrill (1998). The dissolved metals vary with the seasonal flows.

Water quality data on total recoverable metals collected in the Spokane River show seasonal variation at the Washington-Idaho border. The total recoverable metals data show increasing trends as river flows increase in the spring. Wa ter quality data on hardness collected in the Spokane River do not show significant seasonal variation at the Washington-Idaho border. However, hardness in the river does exhibit a large summer variation in the lower reaches downstream of where significant groundwater contri butions to the river ar e observed (Table 3).Spokane River Metals TMDL Page 7 Table 2

. Seasonal Statistics of the Spokane River Total Recoverable Metals at Washington-Idaho Border

Cadmium

(μg/L) Lead (μg/L) Zinc (μg/L) Time Period

Median Standard

Deviation Median Standard

Deviation Median Standard

Deviation

Winter (December-February) 0.3 0.8 1.5 6.2 86.5 12.3

Spring (March-May) 0.4 0.0 3.1 6.4 89.6 10.3

Summer (June-August) 0.3 0.1 1.6 3.1 47.0 18.0

Fall (September-November) 0.2 0.1 1.2 0.7 49.0 23.7

Annual (January-December) 0.3 0.5 1.5 4.6 79.5 23.0

Table 3

. Seasonal Statistics of the Spokane River Hardness (in mg / L as CaCO 3 )

River Mile

100.7 River Mile

96.0 River Mile

85.3 River Mile

66.0 Time Period

Median Standard

Deviation Median Standard

Deviation Median Standard

Deviation Median Standard

Deviation

Winter (December-February) 22.0 1.7 23.0 1.1 27.0 3.1 37.0 6.3

Spring (March-May) 23.0 2.2 23.0 0.6 26.0 1.6 36.0 2.3

Summer (June-August) 20.0 2.6 20.0 1.7 59.5 29.9 72.0 26.3

Fall (September-November) 21.0 2.0 20.5 0.7 37.0 3.4 58.0 6.3

Annual (January-December) 22.0 2.3 22.0 1.4 32.5 20.4 48.5 20.7Spokane River Metals TMDL Page 8 

# Modeling Approach

Linking Water Quality and Pollutant Sources

A mass-balance model of the Spokane River was de veloped to evaluate th e effect of different effluent loading on metals and hardness (Pelletier and Merrill, 1998). The model includes a flow

balance that accounts for inflow of water from th e outlet of Lake Coeur d'Alene, inflow from permitted discharges, and flow exchanges from the aquifer and Hangman Creek. The model application assumed that Lake Coeur d'Alen e outflow met Washingt on State water quality standards with a hardness of 20 mg/L as CaCO 3 and wastewater discharges met aquatic life toxicity criteria end-of-pipe at e effluent hardness. The model divides the river into 14 reaches

from Lake Coeur d'Alene to near the headwaters of Long Lake (RM 64.6).

Calibration of the model to actual conditions in th e river involved estimation of aquifer hardness

and metals to match observed concentrations in th e river. All other input s in the flow and mass balance equations were directly estimated from available data. Relationships between hardness, metals, and flow are known at various locati ons in the river based on long-term ambient monitoring data. The model was calibrated for hardness by starting with the known upstream hardness and adjusting the groundwater hardness to equate predictions with observed values. After the hardness was calibrated, the same a pproach was used to estimate the dissolved cadmium, lead, and zinc of the inflows.

The calibrated mass-balance model was used to estim ate concentrations of metals in the river for a variety of river flows and effluent flows. The model was used to evaluate whether water quality standards would be violated in the ri ver assuming the river met Washington State water quality standards when it leaves Lake Coeur d' Alene and the effluent met aquatic life criteriabased limits at the point of discharge based on e ffluent hardness. The model results show that

standards would be met for cadmium and zinc. The standards for lead would be met if the

maximum concentration of total recoverable l ead in the effluent does not exceed the value predicted from the extrapolated tangent line of the chronic criterion equation.



# Loading Capacity

Identification of the loading capacity is an impor tant step in developing TMDLs. The loading capacity is the amount of pollutant a water body can receive and still meet water quality standards. By definition, a TMDL is the sum of the allocations. An allocation is defined as the portion of a receiving water's load ing capacity that is assigned to a particular source. EPA defines the loading capacity as "the greatest amount of loading that a wa ter can receive without violating water quality standards."Spokane River Metals TMDL Page 9 The hardness of the wastewater effluent from th e various discharges is significantly higher than the hardness of the Spokane River. The metals criteria for protection of aquatic life are based on hardness, because the toxi city of metals decreases as hardness increases. Thus, as the Spokane River flows downstream, its loading capacity for metals increases due to inflow of harder water.

The Spokane River Metals TMDL utilizes a different measure than “daily loads” to fulfill requirements of Section 303(d). Instead, the TMDL is expressed in terms of concentration as allowed under EPA regulations [defined as “other appropriate measures” in 40 CFR §130.2(i)]. In this case, a concentration measure is appropri ate because the relationship between the effluent hardness-based criterion and the receiving water quality holds for all river and effluent flow

rates. The use of effluent flow to establis h a loading limit would not only be unnecessary, but also could be misconstrued to represent a restric tion on effluent flow. Also, a loading limit could require unnecessary TMDL and permit modificati ons to change loading limits as communities grow and flows increase.



# Load and Waste Load Allocations

Cadmium, lead, and zinc concentrations in the Spokane River at the stat e line often exceed water quality standards. EPA and Idaho Department of Environmental Quality are developing a TMDL to control pollution sources in Idaho. One of the necessary objectives of the work is to meet Washington's water quality standards in th e Spokane River. The load allocation is the concentration required to meet the chronic criteri on at the outlet of Lake Coeur d'Alene. The wasteload allocations in Washington assure co mpliance with Washington State water quality

standards if the criteria are met only at the Washington-Idaho border

The waste load allocation is based on the most restrictive permit limits based on the comparison

of:

• Potential limits based on meeting aquatic life criteria at effluent hardness, or

• Potential limits, plus 10%, based on maintaining ex isting concentrations of metals in effluent, where adequate data exist.

Whichever method results in the lower limit is established as the waste load allocation.Spokane River Metals TMDL Page 10 

# Margin of Safety

The statute requires that a margin of safety be identified to account for uncertainty when establishing a TMDL. The margin of safety can be explicit in the form of an allocation, or implicit in the use of conservative assumptions in the analysis. Several assumptions and critical conditions used in the modeling analysis of the Spokane River TMDL provide an inherent margin of safety as required by the statute. These conservative assumptions and critical

conditions are listed below:

• Effluent hardness was assumed to be the 10 th percentile hardness as measured at the Spokane Advanced Wastewater Treatment Plant

• Effluent hardness was assumed to be a lo wer value based on a mixture of river and groundwater used for production proposes at th e Kaiser Industrial Wastewater Treatment

Plant.

• Effluent total recoverable metal concentrations were assumed to be approximate maximum values reported.

• The hardness for the outflow for Lake Coeur d'Alene was assumed to be the seasonal 10 th
percentile for the low flow and high flow periods, and the 5 th percentile from all seasons.

• The hardness in the river was assumed to equal the 10% prediction limits from the regression equations with flow.

• The dissolved metals were assumed to equal the 90% prediction limits from the regressions with flow.



# Summary Implementation Strategy

The success of the TMDL largely relies on c ontrolling the upstream sources in Idaho so that the toxicity criteria of Washington' s Water Quality Standards for Surface Water (WAC 173-201 A) are met at the Washingt on/Idaho border. Effluent limits will be placed in all NPDES permits fo r direct discharge to the Sp okane River where adequate

low-level effluent data exist.Spokane River Metals TMDL Page 11 

## Monitoring Plan for TMDLs Developed Under the Phased Approach

EPA (1991) guidance calls for a monitoring plan for TMDLs where implementation will be phased in over time. The monitoring is conducted to provide assurance that the control measures achieve the expected load reductions. 

### All Spokane River NPDES discharge permits in Washington, which do not currently have adequa te metals monitoring, will be opened and monthly monitoring will be added by the e nd of 1999, which will follow appropriate clean sampling protocols and EPA 1600-series an alytical methods for total recoverable. Quarterly dissolved metals mon itoring should also be included if source-specific effluent

dissolved/total recoverable metals ratios are to be determined.



## Reasonable Assurances

All Spokane River dischargers will have the TMDL-based limits plac ed in their permits within 21⁄2 years from the initiation of monthly low level monitoring. Monitoring requirements have already been placed in th e Liberty Lake Sewer District permit and

effluent metals limits will be put into City of Sp okane's permit which is now targeted to

be issued in June 1999.Spokane River Metals TMDL Page 12 

# References Cited

Bailey, G.C and J. Saltes. Fishery Assessment of the Upper Spokane River. Report 46. State of Washington Water Research Center, Pullman, WA.

Crosby, J.W., et al. 1971. Investigation of techniques to provide advance warning of groundwater pollution hazards with special refe rence to aquifers in glacial outwash. Final Report to OWRR, Project No. B-005-WASH . State of Washington Water Research Center, Pullman, WA.

Knight, D.T. 1998. Watershed Approach to Wa ter Quality Management Needs Assessment for the Spokane Water Quality Management Area (WRIA 54-57). Publication No. WQ-98- 21. Washington State Departme nt of Ecology, Spokane, WA

Pelletier, G. and K. Merrill. 1998. Cadmium, Lead, and Zinc in the Spokane River - Recommendations for Total Maximum Daily Lo ads and Waste Load Allocations. Publ. No. 98-329. Washington State Depa rtment of Ecology, Olympia, WA.

SASSI, 1993. 1992 Washington State Salmon a nd Steelhead Stock I nventory. Washington Department of Fisheries, Washington Depa rtment of Wildlife and Western Washington Treaty Indian Tribes. Olympia, WA.

U.S. Environmental Protection Agency. 1991. Guidance for Water Quality-based Decisions: The TMDL Process. EPA 440/4-91-001. Washington, DC.Spokane River Metals TMDL Page 13 

# Figures

# Appendix A

Public Participation Materials

# Appendix B

Responses to Comments Received

# Appendix C

Quality Assurance Project Plan

# Appendix D

Technical Report

Bound Separately as Ecol ogy Publication No. 98-329