Walla Walla River 

Chlorinated Pesticides and PCBs 

Total Maximum Daily Load 

(Water Cleanup Plan) 

Submittal Report 

February 2006 

Publication Number 05-10-079 

Walla Walla River 

Chlorinated Pesticides and PCBs 

Total Maximum Daily Load 

(Water Cleanup Plan) 

Submittal Report 

Prepared by: 

Donovan Gray, Karin Baldwin, and Art Johnson 

Washington State Department of Ecology 

Water Quality Program 

4601 N. Monroe Street 

Spokane, Washington 99205-1295 

February 2006 

Publication Number 05-10-079 
For additional copies of this document contact: 

Department of Ecology 

Water Quality Program 

Eastern Regional Office 

4601 N. Monroe Street 

Spokane, Washington 99205-1295 

Telephone: 509-329-3557 

If you need this publication in an alternate format, please call the Water Quality Program at 

509-329-3557. Persons with hearing loss can call 711 for Washington Relay Service. Persons 

with a speech disability can call 877-833-6341.
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page i 

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Table of Contents 

List of Tables and Figures............................................................................................................... ii 

Acknowledgements........................................................................................................................iii 

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

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

Applicable Criteria.......................................................................................................................... 9 

Water Quality and Resource Impairments.................................................................................... 13 

Seasonal Variation ........................................................................................................................ 17 

Technical Analysis........................................................................................................................ 19 

Loading Capacity.......................................................................................................................... 26 

Load and Wasteload Allocations .................................................................................................. 29 

Margin of Safety ........................................................................................................................... 37 

Summary Implementation Strategy .............................................................................................. 39 

References Cited ........................................................................................................................... 57 

Appendix A - Evaluation of Toxics in the Walla Walla River................................................. A-59 

Appendix B - Walla Walla Watershed Plan ............................................................................. B-61 

Appendix C - Stormwater Management Manual for Eastern Washingtont.............................. C-63 

Appendix D - Model Municipal Stormwater Manual for Eastern Washington........................ D-65 

Appendix E - Upper Yakima Submittal Report.........................................................................E-67 

Appendix F - Agency for toxic Substance Registry ..................................................................F-69 

Appendix G - Acronyms and Abbreviations ............................................................................ G-71 

Appendix H - Responsiveness Summary.................................................................................. H-73 

Appendix I - Public Participation Materials .............................................................................I-139 
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List of Tables and Figures 

Figure 1. Water Resource Inventory Area (WRIA) 32.................................................................. 4 

Figure 2. Land Use in the Walla Walla Basin, 1986-1996 data .................................................... 5 

Table 1. Applicable Washington State Water Quality Criteria* for Chlorinated Pesticides and 

PCBs ............................................................................................................................ 11 

Table 2. Oregon State Water Quality Criteria* for Chlorinated Pesticides and PCBs. ............... 12 

Table 3. Walla Walla Sub basin (WRIA 32) Toxics 303(d) Listings and Impairments.............. 13 

Figure 4. Typical flow patterns in the Walla Walla drainage (.................................................... 18 

Figure 5. Water quality monitoring sites where SPMDs were deployed..................................... 20 

Figure 6. Location of Walla Walla and College Place WWTPs.................................................. 21 

Figure 7. Location of fish samples............................................................................................... 22 

Table 4. Loading Capacity for Chlorinated Pesticides and PCBs in the Lower 

Walla Walla River ........................................................................................................ 26 

Table 5. Loading capacities for the Walla Walla mainstem and tributaries ................................ 27 

Table 6. Loading Capacities for the East Little Walla Walla River and Yellowhawk Creek .... 27 

Table 7. Recommended load reductions in the mainstem Lower Walla Walla River................. 28 

Table 8. Applicable Washington State Water Quality Criteria* for Chlorinated Pesticides and 

PCBs as the basis for the load and wasteload allocations and TSS targets.................. 29 

Table 9. Load allocations for the Walla Walla mainstem and tributaries, except for the East Little 

Walla Walla River and Yellowhawk Creek. ................................................................ 31 

Table 10. Load allocations for the East Little Walla Walla River and Yellowhawk Creek. ...... 31 

Table 11. Fish Consumption Rates of CRITFC Member Tribes and Approximate Fish Meals 

per Month.................................................................................................................... 31 

Table 12. TSS targets/goals and corresponding t-DDT concentrations for the protection of 

average and high fish consumers among the general public and tribal members. ...... 32 

Table 13. Water quality targets for the Walla Walla River drainage. ......................................... 33 

Table 14. Water Quality Targets for the East Walla Walla River and Yellowhawk Creek. ....... 34 

Table 15. Wasteload and Load allocations for PCBs in Garrison Creek, Mill Creek, and 

Yellowhawk Creek...................................................................................................... 36 

Table 16. Timelines for the achievement of interim targets and state water quality standards... 40 

Table 17. Summary of management goals for the Walla Walla chlorinated pesticides and 

PCBs TMDL. .............................................................................................................. 41 

Table 18. Organization of TMDL entities and their contributions. ............................................. 45 

Table 19. Miscellaneous existing projects related to water quality improvement in WRIA 32. 49
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Acknowledgements 

The authors of this report would like to thank the following people for their contributions: 

• The Walla Walla TMDL advisory group for their valuable recommendations and support 

• The Confederated Tribes of the Umatilla Indian Reservations (CTUIR) for their valuable 

assistance during the sampling stages of the TMDL evaluation. 

• Washington State Department of Ecology, Water Quality Program Staff for their valuable 

advice and support 

• Helen Rueda, EPA Region 10, for reviewing drafts of the report 
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Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 1 

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Introduction 

The Washington State Department of Ecology (Ecology) is establishing a water quality clean-up 

plan or total maximum daily load (TMDL) for the Washington State portion of the Walla Walla 

basin that covers the pollution parameters of chlorinated pesticides and PCBs. This TMDL will 

address potential impairments of beneficial uses of the Walla Walla River and its tributaries in 

Washington State. Ecology does not have jurisdiction over the portion of the watershed in 

Oregon State that comprises roughly a quarter of the entire Walla Walla watershed. However, 

some load allocations are given in this TMDL for streams in Washington where the headwaters 

are in Oregon. Therefore, Ecology is mindful of the need to develop and foster strong and 

effective cross-border ties that will help coordinate implementation efforts and ensure water 

quality is protected across the basin. 

Under the Clean Water Act, every state has its own water quality standards designed to protect, 

restore, and preserve water quality. Water quality standards consist of designated uses (such as 

cold-water biota and drinking water supply) and numeric standards to achieve those uses. When 

a water body fails to meet water quality standards after application of best management practices 

(BMPs) and required technology-based controls, the Clean Water Act requires that the state 

place the water body on a list of impaired water bodies and to prepare an analysis called a 

TMDL. BMPs usually apply to nonpoint sources and are defined in WAC 173-201A as 

‘physical, structural and/or managerial practices approved by the department that, when used 

singularly or in combination, prevent or reduce pollutant discharges.’ Technology-based control 

typically applies to point sources and is the best technology available that is economically 

achievable and can be applied to facilities to reduce pollution discharges. The U.S. 

Environmental Protection Agency (EPA) has established regulations [40 Code of Federal 

Regulations (CFR) Part 130] and developed guidance for setting TMDLs (EPA, 1991). In June 

2002, Washington State Department of Ecology developed its own guidance (which has been 

used in the writing of this document) for setting TMDLs. 

The goal of a TMDL is to ensure that the impaired water body will attain water quality standards 

within a reasonable time period. A TMDL includes a written, quantitative assessment of the 

water quality problem and of the pollutant sources that cause the problem. The TMDL 

determines the amount of a given pollutant (called the loading capacity) that can be discharged to 

the water body and still meet water quality standards and, subsequently, 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 facility’s discharge pipe, that facility’s share of the loading capacity 

is a wasteload allocation. If the pollution comes from a diffuse source (referred to as a nonpoint 

source) such as runoff from roads, parking lots, and fields, that share is a load allocation. 

However, each location that makes up the diffuse source does not receive an individual 

allocation. Load allocations are assigned to the broad nonpoint source. 

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 problem or its loading 

capacity. The sum of the individual allocations and the margin of safety must be equal to or less 

than the loading capacity. 
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The general purposes of this submittal document are to: 

• Provide an analysis of chlorinated pesticides and PCB data from the Walla Walla River 

and tributaries from sampling performed by the Environmental Assessment Program 

(EAP) of the Washington State Department of Ecology from May 2002 through 

September 2003. 

• Identify potential point and nonpoint sources of chlorinated pesticides and PCB pollution. 

• Summarize ongoing and planned actions that will allow the Walla Walla River and its 

tributaries to meet state water quality standards. 

• Summarize proposed monitoring activities to verify whether those standards are being 

met. 

• Fulfill requirements of the federal Clean Water Act. 

A detailed implementation plan (DIP) will be developed within one year after the TMDL 

approval by the Environmental Protection Agency (EAP) and will be based on the information 

presented in this document. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 3 

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Background 

Basin Description 

The Walla Walla River is located in the southeast corner of Washington State (Figure 1). The 

river extends 61 miles from its headwaters in Oregon to its confluence with the Columbia River. 

The drainage basin covers approximately 1,760 square-miles. Approximately three-quarters (73 

percent) of the drainage and the last 40 miles of the mainstem lie within Washington. In 

downstream order, the major Washington tributaries are Russell Creek, Reser Creek, 

Cottonwood Creek, Birch Creek, Yellowhawk Creek, Stone Creek, Garrison Creek, Cold Creek, 

Mill Creek, East Little Walla Walla River, West Little Walla Walla River, Dry Creek, Mud 

Creek, Pine Creek, the Touchet River, and the Gardena Creek. 

Mill Creek flows from municipal watershed conditions in the Blue Mountains. Most of the city 

of Walla Walla’s drinking water comes from a 36 square-mile protected portion of upper Mill 

Creek. Approximately 14 miles below the waterworks, part of its flow is diverted to Yellowhawk 

and Garrison creeks year round for irrigation purposes (Nicholson, pers. comm., 2005). 

The two major permitted discharges in the basin are the Walla Walla Wastewater Treatment 

Plant (WWTP) that discharges to Mill Creek at river mile (R.M.) 5.4 and the College Place 

WWTP that discharges to Garrison Creek at R.M. 1.0. Yellowhawk, Garrison, and Mill creeks 

enter the Walla Walla River between R.M. 37.9 and 33.6. The drainage area of the greater Mill 

Creek watershed is 96 square-miles. 
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Figure 1. Water Resource Inventory Area (WRIA) 32
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 5 

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The Washington side of the Walla Walla basin has few urban areas. The Washington State 

Office of Financial Management’s (OFM) most recent census results show there were 

approximately 56,700 people living in Walla Walla County in 2004. The major cities are Walla 

Walla and College Place, with a combined population of less than 40,000. Starting as early as the 

1920s, the principal form of land use was production of small grains such as wheat and barley, 

and forage crops like alfalfa, and row crops (Mapes, 1969). Currently, wheat, pasture, potatoes, 

alfalfa seed, and hay are the largest percentage of the irrigated crops. Pasture makes up roughly a 

quarter of irrigated lands on the Washington side of the Walla Walla basin. Other crops include 

onions, peas, grapes, apples, asparagus, and barley. Roughly 25 percent of the total acreage in 

the Walla Walla basin is under the Conservation Reserve Program (CRP), and just less than 1 

percent is under the Conservation Reserve Enhancement Program (CREP) (Walla Walla County 

and Walla Walla Basin Watershed Council, 2004). Figure 2 shows land use patterns as of the late 

1980s/early 1990s. About 91 percent of land on the Washington side of the Walla Walla basin is 

privately owned with approximately 6 percent and 2 percent owned by federal and state entities 

respectively (Hashim and Stalmaster, 2004). 

Figure 2. Land Use in the Walla Walla Basin, 1986-1996 data 

The Walla Walla basin consists primarily of ridges and rolling hills interspersed with valleys. 

The ridges and hills are underlain by loessal (windblown silt) formations up to 250 feet thick, 

except to the west where the soils are sandy. The valley floors are underlain by floodplain 

alluvium ranging in grain size from gravel to silt. Beneath the floodplain alluvium are clay units 

as much as 500 feet thick. Most benches within the valleys and terraces on the valley sides are 

composed of sand and silt of the Touchet Beds deposited by catastrophic floods from Montana’s 
Page 6 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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glacial Lake Missoula. The last flood series was between about 15,000 and 13,000 years ago. 

Under all the sediment, and exposed at the surface locally, are the Columbia River Basalts 

(CRB) which are thousands of feet of lava that erupted 17 to 6 million years ago. There are two 

major aquifers in the area. The basalts are the deep confined aquifer. The gravels are the shallow 

unconfined aquifer. In general, streams are in hydraulic continuity with the shallow gravel 

aquifer. In the Walla Walla Valley the clays serve to slow water movement between the shallow 

aquifer and the deep basalt aquifer (Newcomb, 1965, and Carson and Pogue, 1996). Folds and 

faults in the basalt can work as natural dams, creating impediments to groundwater flow, large 

differences in groundwater pressure, and fluctuations in water levels (HDR/EES Inc., 2005). 

Elevation exerts significant control over climate in the Walla Walla basin, presenting 

temperature and precipitation gradients from west to east with the rise in elevation towards the 

Blue Mountains. Local climate varies from warm and semiarid in the western lowlands that lie in 

the rain shadow of the Cascade Mountains, to cool and relatively wet at higher elevations in the 

Blue Mountains. The average temperatures range from 20° to 25° F in the winter to 90° F to 

95°F in the summer, with summer highs peaking in July and decreasing in late August. The 

lower west end of the basin averages less than 10 inches of precipitation per year (extremes can 

be as low as 4 inches), while the higher east end of the basin averages 40 to 60 inches of 

precipitation per year (HDR/EES Inc., 2005). 

Although highly altered by grazing, prescribed burning, wildfires, and agriculture, remnants of 

the original grassland and shrub-steppe vegetation remain. However, the preliminary draft of the 

Walla Walla Watershed Plan (January 2005, section 3 pg. 4) states that most disturbed areas not 

under cultivation can be dominated by non-native invasive species such as cheat grass (Bromus 

tectorum), velvet grass (Holcus lanatus), yellow star thistle (Centaurea solstitialis), barnyard 

grass (Echinochloa crusgalli), tansy (Tanacetum vulgar), and rattlegrass (Bromus brizaeformis). 

Of these, Bromus tectorum and Centaurea solstitialis may currently be the most significant 

invasive species (Schirman, pers. comm., 2005). Riparian vegetation is limited in most areas 

throughout the basin, although considerable riparian enhancement has occurred through efforts 

by Walla Walla County and Columbia Conservation Districts. Areas of shrubs and grasses in the 

western lowlands gradually give way to the open woodlands and then transition into the upland 

coniferous forests of the Blue Mountains at higher elevations in the east (HDR/EES Inc., 2005). 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 7 

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Ecology’s Chlorinated Pesticide and PCB Study 

In 1996, the Walla Walla River was listed by the state of Washington under Section 303(d) of the 

Clean Water Act for non-attainment of the EPA human health criteria for 4,4’-DDE, 4,4’-DDD, 

dieldrin, chlordane, hexachlorobenzene, heptachlor epoxide, and PCB-1260 in edible fish tissue. 

The listings are based on sampling done by Ecology in 1993 (Davis et al., 1995). The 1996 

303(d) listings were maintained on the 1998 and draft 2002/2004 lists (Table 3). Garrison Creek, 

a Walla Walla tributary, was also proposed for listing in 2002/2004 due to human health 

violations of standards for DDT compounds and hexachlorobenzene in water samples (White et 

al., 1998). Prior to Ecology’s TMDL evaluation, toxaphene was absent from Washington’s most 

recent toxin listings for the Walla Walla as it was previously unknown to violate water quality 

standards. However, Ecology’s 2002-2003 TMDL evaluation found Pine Creek to have 

relatively high concentrations of toxaphene, and is shown in this report as impaired. 

Chlorinated pesticides, their breakdown products, and polychlorinated biphenyls (PCBs) are no 

longer used in the United States, having been banned in the 1970s and 1980s for ecological 

concerns. They are now classed as probable human carcinogens by EPA. Chlorinated pesticides 

have a range of possible negative human health effects, including nervous system, digestive 

system, immune system, and reproductive system effects. They do not breakdown easily and 

bind strongly with the soil, and so often persist in the environment for many years. In the Walla 

Walla River watershed, the primary source of chlorinated pesticides is thought to be from soil 

erosion from agricultural lands and runoff from urban areas. 

Like chlorinated pesticides, PCBs (Polychlorinated Biphenyls) also breakdown very slowly and 

persist in the environment. For this reason, both chlorinated pesticides and PCBs are commonly 

referred to as ‘legacy pollutants’. PCBs do not burn easily, have been used widely as coolants 

and lubricants, and because they do not conduct electrical charges readily, they have been used 

as insulators in electrical transformers. PCBs can have severe human health effects, possibly 

causing stomach, liver and kidney damage, skin irritation, and thyroid gland injuries. They are 

also suspected to be probable human carcinogens. PCBs released into the air can enter the land 

or water by settling or from runoff in snow and rain. Both chlorinated pesticides and PCBs can 

build up in fish tissue and can reach levels much higher than those in the water, and can 

accumulate further in humans through fish consumption. Detailed profiles including use, 

regulations, environmental occurrence, and health effects have been prepared by the agency for 

Toxic Substances and Disease Registry (see Appendix F). 

In 2002-2003, Ecology initiated a total maximum daily load (TMDL) evaluation of chlorinated 

pesticides and PCBs in the Walla Walla River and its tributaries. The evaluation was based on a 

field study that sampled concentrations of these pollutants in fish tissue and the water column, 

including sampling of the waste water treatment plant effluents for the cities of Walla Walla and 

College Place. The study area included the mainstem of the Walla Walla River and its tributaries 

from the Oregon border to the Columbia River. Tributary sampling was confined to sites at or 

near their mouths. Water sampling was done primarily on a quarterly basis: May-June, AugustSeptember, November-December of 2002, and November-December of 2003. Fish sampling was 

limited to resident mainstem species with upper river fish being analyzed separately from lower 

river fish (see the sampling section under Technical Analysis for further information). 
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The primary goals of the field study for the Walla Walla River chlorinated pesticide/PCB 

TMDL were to 1) quantify water column concentrations and loadings of 303(d) listed pesticides 

and PCBs in the Walla Walla mainstem, major tributaries, and significant point sources; 

2) recommend numerical water quality targets that will result in fish meeting human health 

standards; and 3) propose load allocations to meet the targets. In pursuit of these goals, sufficient 

data were obtained to allow an assessment of human health risk from fish consumption. 

Benchmarks were established to gauge future improvements in water quality. 

Historical application of chlorinated pesticides to soils and crops is the primary source of these 

chemicals in rivers and streams in agricultural areas like the Walla Walla basin. Because 

chlorinated pesticides bind strongly to soil particles, the chief means to meeting pesticide 

standards in the Walla Walla River and its tributaries is to reduce the amount of soil entering 

these water bodies. A report by Economic and Engineering Services, Inc. (EES, as cited from 

Kuttel, 2001; Pacific Groundwater Group, 1995; Saul et al., 2001) has concluded that erosion of 

fine sediment is a problem in the lower Walla Walla basin (EES, 2003). EES identified a number 

of sources of sediment including road-building and logging activities in the upper reaches of 

tributaries, recreational vehicle use, and urban runoff. They concluded, however, that “given the 

predominance of agricultural land use in the watershed, agricultural practices have been 

identified as the principal source of fine sediment.” Historically, agricultural areas have been 

large contributors to the suspended sediment problem in some drainages in the Walla Walla. 

Studies conducted in the 1960s showed yields of suspended sediment were greatest in the highly 

cultivated Touchet River and Dry Creek drainage basins that were contributing up to 80 percent 

of the total sediment load to the Walla Walla River (Mapes, 1969). Soils in these two drainages 

consist of well-drained silty loams and very fine sandy loams that are highly susceptible to 

erosion from runoff. Recently, much work has been done in the area to address agricultural 

sources of the problem. 

Total suspended solids (TSS) and turbidity are proposed as water quality indicators and surrogate 

numerical targets for chlorinated pesticides in the Walla Walla River and its tributaries. Setting 

water quality targets based on TSS and turbidity has the advantage of translating more directly 

into land use practices and being easier and less expensive to monitor than trace chemical 

concentrations. Additionally, TSS and turbidity levels in rivers and streams have a direct and 

quantifiable effect on the health of fish and other aquatic organisms as well as aesthetic values. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 9 

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Applicable Criteria 

The Washington State Water Quality Standards are published pursuant to Chapter 90.48 of the 

Revised Code of Washington (RCW). The authority to adopt rules, regulations, and standards as 

necessary to protect the environment is vested with the state Department of Ecology. Under 

Section 303(c)(3) of the federal Clean Water Act, the EPA Regional Administrator approves the 

water quality standards adopted by the state. Through adoption of these standards, Washington 

State has designated certain characteristic uses to be protected and the criteria necessary to 

protect these uses (WAC 173-201A). 

Although the Washington State Water Quality Standards were revised and adopted by the state 

on July 1, 2003, the standards from November 1997 will be used for this TMDL. The new water 

quality standards will not take effect for projects that require federal action until EPA approves 

the new standards. TMDLs under development with field work completed will continue to use 

the 1997 version of the water quality standards, per Ecology document Concise Explanatory 

Statement and Responsiveness Summary for the Adoption of Water Quality Standards, Chapter 

173-201A WAC published July 1, 2003. At the time of writing this report, revisions to the water 

use and criteria classes (WAC 173-201A-030) and toxic substances sections (WAC 173-201A040) had not yet been approved, thus the 1997 standards are employed. However, the toxics 

criteria for this TMDL are not being revised and are still in effect in the same form they will be 

in after the revised standards are approved. 

Under WAC 173-201A-030 (1997) the Walla Walla River drainage is a predominately a Class A 

system, although portions of the mainstem and Mill Creek are Class B. The characteristic 

beneficial uses of a Class A and Class B water bodies are described in WAC 173-201A-030 

(2)(a) and (b) and WAC 173-201A-030 (3)(a) and(b) (1997) respectively as: 

Characteristic uses shall include, but not be limited 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, rearing, spawning, and harvesting. 

Clam, oyster, and mussel rearing, spawning, and harvesting. 

Crustaceans and other shellfish (crabs, shrimp, crayfish, scallops, etc.) 

rearing, spawning, and harvesting. 

(iv) Wildlife habitat. 

(v) Recreation (primary contact recreation, sport fishing, 

boating, and aesthetic enjoyment). 

(vi) Commerce and navigation. 

 [WAC 173-201A-030(2)(b)and (3)(b)] 

State law does not establish a ranking priority among the beneficial uses, but the individual 

waters are expected to support all uses within the classification. 
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Toxic Substances: Washington State Regulations 

WAC 173-201A-030 (2) (vii) and (3) (vii) state the following with regard to toxic substances: 

 Toxic, radioactive, or deleterious material concentrations shall be below those which 

have the potential either singularly or cumulatively to adversely affect characteristic 

water uses, cause acute or chronic conditions to the most sensitive biota dependent upon 

those waters, or adversely affect public health, as determined by the department (see 

WAC 173-201A-040 and 173-201A-050). 

Toxics substances are further addressed in WAC 173-201A-040 as follows (selected sections): 

(1) Toxic substances shall not be introduced above natural background levels in waters 

of the state which have the potential either singularly or cumulatively to adversely affect 

characteristic water uses, cause acute or chronic toxicity to the most sensitive biota 

dependent upon those waters, or adversely affect public health, as determined by the 

department. 

(2) The department shall employ or require chemical testing, acute and chronic toxicity 

testing, and biological assessments, as appropriate, to evaluate compliance with 

subsection (1) of this section and to ensure that aquatic communities and the existing and 

characteristic beneficial uses of waters are being fully protected. 

(5) Concentrations of toxic and other substances with toxic propensities not listed in 

Subsection (3) of this section shall be determined in consideration of USEPA Quality 

Criteria for Water, 1986, as revised, and other relevant information as appropriate. 

Human health-based water quality criteria used by the state are contained in 40 CFR 

131.36 (known as the National Toxics Rule). 

(6) Risk-based criteria for carcinogenic substances shall be selected such that the upperbound excess cancer risk is less than or equal to one in one million. 

Washington State water quality criteria that apply to 303(d) listed pesticides and PCBs in the 

Walla Walla drainage are shown in Table 1 [from sections (3) and (5) of WAC 173-201A-040]. 

The human health criteria are for a one in one million increased lifetime cancer risk from 

consumption of water and fish or fish only. A fish consumption rate of 6.5 grams per day and a 

water consumption rate of 2 liters per day are assumed. These criteria were promulgated for 

Washington in the EPA National Toxics Rule (40 CFR 131.36). 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 11 

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Table 1. Applicable Washington State Water Quality Criteria* for Chlorinated Pesticides and PCBs 

(ng/L; parts per trillion). 

Criteria for Protection Criteria for Protection 

of Aquatic Life of Human Health 

Chemical Freshwater Freshwater Water and Fish Fish 

Acute Chronic Consumption Consumption 

4,4'-DDT 0.59 0.59 

4,4'-DDE 0.59 0.59 

4,4'-DDD 0.83 0.84 

DDT (and metabolites) 1,100 1.0 

Dieldrin 2,500 1.9 0.14 0.14 

Heptachlor 520 3.8 0.21 0.21 

Heptachlor epoxide 0.10 0.11 

Hexachlorobenzene 0.75 0.77 

Chlordane 2,400 4.3 0.57 0.59 

Toxaphene 730 0.2 0.73 0.75 

PCBs 2,000 14 0.17 0.17 

*WAC 173-201A-040 (1997 version http://www.ecy.wa.gov/programs/wq/swqs/wac173201a1997.pdf) EPA promulgated the human health criteria for Washington in 40 CFR 131.36 

Toxic Substances: Oregon State Regulations 

Approximately one quarter of the Walla Walla drainage lies in Oregon State and does not fall 

under Washington State Department of Ecology’s jurisdiction. Beneficial uses and water quality 

standards for the surface waters of the state of Oregon are codified in the Oregon Administrative 

Rules (OAR) Chapter 340, Division 41. Beneficial uses for the Walla Walla River basin are 

given in OAR 340-041-0330 and are shown below 

Beneficial Uses 

Walla Walla River Mainstem 

from Confluence of North and 

South Forks to State Line 

All Other 

Basin 

Streams *

Public domestic water supply X X 

*

Private domestic water supply X X 

Industrial water supply X 

Irrigation X X 

Livestock watering X X 

Anadromous fish passage X X 

Salmonid fish rearing X X 

Salmonid fish spawning X X 

Resident fish & aquatic Life X X 

Wildlife & hunting X X 

Fishing X X 

Boating X X 

Water contact recreation X X 

Aesthetic quality X X 

Hydro power X 

*With adequate pretreatment (filtration and disinfection) and natural quality to meet drinking water standards. 
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The newly adopted Oregon Administrative Rule (OAR) 340-041-0033 states the following with 

regard to toxic substances. 

(1) Toxic substances may not be introduced above natural background levels in waters of 

the state in amounts, concentrations, or combinations that may be harmful, may 

chemically change to harmful forms in the environment, or may accumulate in sediments 

or bioaccumulate in aquatic life or wildlife to levels that adversely affect public health, 

safety, or welfare of aquatic life, wildlife, or other designated beneficial uses. 

(2) Levels of toxic substances in waters of the state may not exceed the applicable criteria 

listed... 

The revised adopted toxics criteria in Oregon Administrative Rule (OAR) 340-0410-0033 

are not Water Quality Standards as defined under the Clean Water Act as they have not 

received EPA approval. However, as of February 15, 2005, Oregon Department of 

Environmental Quality (DEQ) has chosen to use the new criteria to produce TMDLs 

where they are overly protective with regard to the ‘applicable’ water quality standards 

(Fitzpatrick, M. pers. comm., 2005). Where the ‘old’ criteria are more stringent these 

continue to be used for Oregon TMDLs until the new criteria are approved by the EPA. A 

complete list of the more stringent criteria can be found in Table 33A of Division 41 at 

http://www.deq.state.or.us/wq/wqrules/wqrules.htm. It should be noted that Table 33A values 

cannot yet be used for listing a water body as impaired because those standards are yet be 

approved by EPA. Table 2 shows the new more stringent Oregon State criteria for the 

toxins addressed in this submittal report. Figures in bold represent the ‘old’ criteria that 

continue to be employed in Oregon TMDLs where they are more stringent than the new 

criteria. 

Table 2. Oregon State Water Quality Criteria* for Chlorinated Pesticides and PCBs (ng/L; 

parts per trillion figures in bold represent ‘old’ criteria still in use where they are more stringent). 

Criteria for Protection Guidance Values for the 

of Aquatic Life Protection of Human Health 

Freshwater Freshwater Water and Fish Fish 

Chemical Acute Chronic Consumption Consumption 

4,4'-DDT 1,100 1.0 0.024 0.024 

4,4'-DDE 0.22 0.22 

4,4'-DDD 0.31 0.31 

Dieldrin 240 1. 9 0.052 0.052 

Heptachlor 520 3.8 0.079 0.079 

Heptachlor epoxide 520 3.8 0.039 0.039 

Hexachlorobenzene 0.28 0.29 

Chlordane 2,400 4.3 0.46 0.48 

Toxaphene 730 0.2 0.28 0.28 

PCBs 2,000 14 0.064 0.064 

*OAR 340-041-0033 (‘new’ criteria) and OAR 340-041-0685 (‘old’ criteria). 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 13 

Submittal Report 

Water Quality and Resource Impairments 

Sampling conducted in 1993 indicated the Washington State’s water quality standards had been 

violated in various water bodies of the Walla Walla drainage and these were then considered 

‘impaired.’ Several of these water bodies were included on both the state’s 1996 and 1998 

Section 303(d) list for non-attainment of the EPA’s human health criteria for 4,4’DDE; 

4,4’DDD; dieldrin; chlordane; hexachlorobenzene; heptachlor epoxide; and PCB 1260 in edible 

fish tissue. Although sections of the Walla Walla and its tributaries were identified as being 

impaired for other factors (including, but not restricted to: pH; dissolved oxygen; and 

temperature), this report addresses only chlorinated pesticides and PCB’s. 

Although parts of the Oregon side of the Walla Walla drainage appear on the 303(d) list as 

impaired for temperature, there are currently no listed impairments for toxins (Butcher, 2005 

pers. comm.). However, it is important to note that in order to meet the most stringent toxin 

target loads it may be necessary to address activities taking place in Oregon with the help of state 

and local authorities at a later date. Toxin impairments in the Walla Walla River watershed that 

are addressed in this TMDL are summarized in Table 3. 

In 2002-2003, Ecology conducted a TMDL evaluation of the chlorinated pesticide and PCB 

problem in the Walla Walla River and its tributaries. This study found several additional 

exceedances previously not on the 1996 and 1998 303(d) lists. These are shown in Table 3 as 

‘other areas not meeting standards’. The deadline for the inclusion of new data in the 2004 

303(d) list was 12/31/2003. Although water quality samples for the Walla Walla TMDL 

assessment had been collected by this time, the data had not yet been analyzed and so were not 

available for inclusion in the current 303(d) list. 

Table 3. Walla Walla Sub basin (WRIA 32) Toxics 303(d) Listings and Impairments. 

Water Body Waterbody 

ID#(old) 

Waterbody 

ID#(new) 

Parameter Medium Township 

Range 

Section 

1996 

List 

1998 

List 

2004 

List 

Other 

areas not 

meeting 

standards 

Walla Walla 

River 

WA-32-

1010 

QE90PI 4,4’-DDT Tissue 07N 

31E 

25 

No No

40970

Walla Walla 

River 

WA-32-

1010 

QE90PI 4,4’-DDE Tissue 07N 

31E 

25 

Yes Yes 

8806 

Walla Walla 

River 

WA-32-

1010 

QE90PI Chlordane Tissue 07N 

31E 

25 

Yes Yes

8804

Walla Walla 

River 

WA-32-

1010 

QE90PI Dieldrin Tissue 07N 

31E 

25 

Yes Yes

8805

Walla Walla 

River 

WA-32-

1010 

QE90PI Heptachlor 

epoxide 

Tissue 07N 

31E 

25 

Yes Yes

8808

Walla Walla 

River 

WA-32-

1010 

QE90PI Hexachlorobenzene Tissue 07N 

31E 

26 

Yes Yes

8809

Walla Walla 

River 

WA-32-

1010 

QE90PI Total PCBs Tissue 07N 

31E 

26 

Yes Yes

8810
Page 14 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

 Submittal Report

Water Body Waterbody 

ID#(old) 

Waterbody 

ID#(new) 

Parameter Medium Township 

Range 

Section 

1996 

List 

1998 

List 

2004 

List 

Other 

areas not 

meeting 

standards 

Walla Walla 

River 

WA-32-

1010 

QE90PI 4,4’-DDE Tissue 07N 

32E 

35 

No No

14178

Garrison 

Creek 

 DH35GB 4,4’-DDT Water 06N 

35E 

3 

No No 

14386 

Garrison 

Creek

 DH35GB 4,4’-DDE Water 06N 

35E 

3 

No No 

40969 

Garrison 

Creek

 DH35GB 4,4’-DDD Water 06N 

35E 

3 

No No 

40968 

Garrison 

Creek 

 DH35GB Hexachlorobenzene Water 06N 

35E 

3 

No No 

14389 

Walla Walla 

River 

 QE90PI Toxaphene Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI 4,4’-DDE Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI 4,4’-DDD Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI Chlordane Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI Dieldrin Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI Heptachlor 

epoxide 

Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI Hexachlorobenze Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI PCBs Tissue 07N 

32E 

21 

No No No X 

Walla Walla 

River 

 QE90PI 4,4’-DDE Water 07N 

32E 

36 

No No No X 

Walla Walla 

River 

 QE90PI Dieldrin Water 07N 

32E 

36 

No No No X 

Walla Walla 

River 

 QE90PI Toxaphene Water 07N 

32E 

36 

No No No X 

Walla Walla 

River 

 QE90PI PCBs Water 07N 

32E 

36 

No No No X 

Walla Walla 

River 

 QE90PI 4,4’-DDE Tissue 07N 

35 

31 

No No No X 

Walla Walla 

River 

 QE90PI Dieldrin Tissue 07N 

35 

No No No X 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 15 

Submittal Report 

Water Body Waterbody 

ID#(old) 

Waterbody 

ID#(new) 

Parameter Medium Township 

Range 

Section 

1996 

List 

1998 

List 

2004 

List 

Other 

areas not 

meeting 

standards 

31 

Walla Walla 

River 

 QE90PI Chlordane Tissue 07N 

35 

31 

No No No X 

Walla Walla 

River 

 QE90PI PCBs Tissue 07N 

35 

31 

No No No X 

Walla Walla 

River 

 QE90PI Toxaphene Tissue 07N 

35 

31 

No No No X 

Walla Walla 

River 

 QE90PI 4,4’-DDE Water 07N 

35E 

31 

No No No X 

Walla Walla 

River 

 QE90PI 4,4’-DDT Water 07N 

35E 

31 

No No No X 

Walla Walla 

River 

 QE90PI Dieldrin Water 07N 

35E 

31 

No No No X 

Walla Walla 

River 

 QE90PI PCBs Water 07N 

35E 

31 

No No No X 

Walla Walla 

River 

 QE90PI Chlordane Water 07N 

35E 

31 

No No No X 

Dry Creek OT03FJ Dieldrin Water 07N 

34E 

29 

No No No X 

Dry Creek OT03FJ Hexachlorobenzene Water 07N 

34E 

29 

No No No X 

East Walla 

Walla River 

 XO26DW 4,4’-DDE Water 06N 

35E 

38 

No No No X 

East Walla 

Walla River

 XO26DW Dieldrin Water 06N 

35E 

38 

No No No X 

East Walla 

Walla River

 XO26DW Heptachlor 

epoxide 

Water 06N 

35E 

38 

No No No X 

Gardena 

Creek 

 t-DDT Water 06N 

33E 

8 

No No No X 

Garrison 

Creek 

 DH35GB t-DDT Water 06N 

35E 

3 

No No No X 

Garrison 

Creek 

 DH35GB Dieldrin Water 06N 

35E 

3 

No No No X 

Garrison 

Creek 

 DH35GB PCBs Water 06N 

35E 

3 

No No No X 

Garrison 

Creek 

 DH35GB Chlordane Water 06N 

35E 

3 

No No No X 

Mill Creek SS77BG t-DDT Water 07N 

35E 

38 

No No No X 
Page 16 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

 Submittal Report

Water Body Waterbody 

ID#(old) 

Waterbody 

ID#(new) 

Parameter Medium Township 

Range 

Section 

1996 

List 

1998 

List 

2004 

List 

Other 

areas not 

meeting 

standards 

Mill Creek SS77BG 4,4’-DDE Water 07N 

35E 

38 

No No No X 

Mill Creek SS77BG Dieldrin Water 07N 

35E 

38 

No No No X 

Mill Creek SS77BG Chlordane Water 07N 

35E 

38 

No No No X 

Mill Creek SS77BG PCBs Water 07N 

35E 

38 

No No No X 

Pine Creek ZX47PC Toxaphene Water 06N 

33E 

1 

No No No X 

Pine Creek ZX47PC 4,4’-DDE Water 06N 

33E 

1 

No No No X 

Pine Creek ZX47PC 4,4’-DDT Water 06N 

33E 

1 

No No No X 

Pine Creek ZX47PC Dieldrin Water 06N 

33E 

1 

No No No X 

Pine Creek ZX47PC Heptachlor 

epoxide 

Water 06N 

33E 

1 

No No No X 

Yellowhawk 

Creek 

 RK92TG 4,4’-DDE Water 06N 

35E 

1 

No No No X 

Yellowhawk 

Creek 

 RK92TG 4,4’-DDT Water 06N 

35E 

1 

No No No X 

Yellowhawk 

Creek 

 RK92TG Dieldrin Water 06N 

35E 

1 

No No No X 

Yellowhawk 

Creek 

 RK92TG PCBs Water 06N 

35E 

1 

No No No X 

Yellowhawk 

Creek 

 RK92TG Chlordane Water 06N 

35E 

1 

No No No X 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 17 

Submittal Report 

Seasonal Variation 

Ecology’s TMDL evaluation of the Walla Walla watershed found a strong correlation between 

the levels of chlorinated pesticides and sediment loads in the water column. The correlation 

between PCBs and sediment loads was weaker. The TMDL evaluation and historical data both 

show that the period of highest stream flow and sediment load is January to June, which 

coincides with the times of highest chlorinated pesticide and PCB concentrations. Both 

chlorinated pesticides and PCBs are well known for their propensity to bind strongly with soil 

particles. This and knowledge of the historical pesticide application in the area, leads to the 

conclusion that the primary source of these chemicals in the Walla Walla River and its tributaries 

was probably soil erosion. 

Elevation can have a significant influence on climate in the Walla Walla Basin. Temperature and 

precipitation gradients exist from west to east with the rise in elevation towards the Blue 

Mountains (see figure 3). 

Figure 3 Isopluvial Map of the Walla Walla Watershed (HDR/EES, from the Walla Walla Watershed Plan, 

Exhibit 3-3, May 2005) 

The majority of soil erosion in the Walla Walla basin occurs from precipitation in winter through 

early spring, flow is sustained though June from snowmelt (see figure 4). Infrequent storm events 

during winter months sometimes cause severe flooding from heavy rain that can contribute the 

highest suspended sediments to the water column (Mapes, 1969). 
Page 18 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

 Submittal Report

0

200

400

600

800

1000

1200

1400

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr

Flow (cfs)

Walla Walla R. Touchet R. Mill Cr.

Yellowhawk Cr. Dry Cr.

Figure 4. Typical flow patterns in the Walla Walla drainage (monthly averages from USGS data, 1951-2002 

USGS gauge stations: 14018500; 14017500; 14015000; 14014000; 1401600). 

Data collected in Ecology’s TMDL evaluation showed marked seasonal variations in the level of 

pesticide/PCB contamination in the mainstem. The highest pesticide concentrations always 

coincided with high flow periods. Similarly the lowest concentrations almost always coincided 

with low flow periods. Runoff from agricultural land is highest during high flow periods which 

coincides with the high concentrations observed. 

The highest PCB concentrations were similarly recorded during high flow months. Seasonal 

fluctuations in pesticide/PCB levels were also pronounced in the tributaries. Pesticides and PCBs 

increased substantially in the Walla Walla mainstem between the Oregon border and Detour 

Road. On average, concentrations increased by factors of two to four from the upper to middle 

river, with an eleven-fold increase for dieldrin. Except for toxaphene, concentrations generally 

decreased in the lower Walla Walla River (below Cummins Bridge). The reduced lower river 

concentrations are largely attributable to dilution by the Touchet River. The lower river averaged 

five times the toxaphene concentrations measured upstream. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 19 

Submittal Report 

Technical Analysis 

This section summarizes the sampling and data analysis methods used in Ecology’s 2002-2003 

TMDL evaluation. Those seeking more detailed information should refer to the technical study 

(see Appendix A). 

Sampling 

Ecology’s TMDL evaluation of chlorinated pesticides and PCBs in the Walla Walla drainage 

was based on water column, fish tissue, and wastewater treatment plant effluent sampling 

conducted from May 2002 to September 2003. 

The purpose of the water sampling was to 1) identify possible or potential sources of 

contamination; 2) assess compliance with human health and aquatic life criteria; 3) test for 

relationships between chlorinated pesticides, TSS, and turbidity; and 4) calculate loadings to and 

within the river. 

Concentrations of 303(d) listed pesticides and PCBs were sampled using semipermeable 

membrane devices (SPMDs) developed by the U.S. Geological Survey. A combination of 

laboratory calibration data and permeability/performance reference compounds (PRCs) spiked in 

deployed SPMDs were used in conjunction with field temperature to obtain an estimate of 

average concentrations. 

An SPMD consists of a polyethylene tube filled with a lipid material called triolein. The rate at 

which SPMDs take up pesticides and PCBs has been determined in the laboratory. The rate 

varies with temperature, water flow, and the amount of biological growth on the membrane 

surface. Performance reference compounds (PRCs) are used to account for differences in these 

parameters between laboratory and field conditions. PRC compounds are spiked into an SPMD 

prior to deployment in a stream. The rate at which the PRCs are lost from the SPMD is 

proportional to the rate at which target compounds in the surrounding water are taken up by the 

SPMD. In other words, PRCs show how well the SPMD is performing compared to what was 

observed in the laboratory. The water column concentration determined from the SPMD is 

adjusted for the loss rate of the PRCs. A high rate of loss means the SPMD is sampling at a high 

rate, i.e., there is a high rate of movement of chemicals through the membrane. SPMDs provide a 

time-weighted average concentration for the chemicals of interest and measure only the 

dissolved ready bioavailable fraction. Ecology’s study deployed SPMDs at ten sites (shown in 

Figure 4) on a quarterly basis for approximately one month each. 

Deployments were timed to provide representative data over the range of runoff conditions that 

normally occur in the drainage. SPMD extracts were analyzed for the 303(d) listed pesticides and 

PCBs. This analysis was later expanded to include toxaphene, based on the examination of the 

chromatograms from the initial deployment in May. When chlorinated organic compounds are 

discharged to surface waters, they partition between dissolved and particulate fractions. Total 

pesticide/PCB concentrations in the Walla Walla drainage were mathematically estimated from 

the SPMD data. This is discussed in greater detail in A Total Maximum Daily Load Evaluation 

for Chlorinated Pesticides and PCBs in the Walla Walla River (see Appendix A). 
Page 20 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

 Submittal Report





















   	



	

	


	











  



	 










 



Figure 5. Water quality monitoring sites where SPMDs were deployed. 

In addition to water sampling at the ten sites shown in Figure 4, wastewater treatment plants 

(WWTPs) at the cities of Walla Walla and College Place were evaluated separately as possible 

sources of chlorinated pesticides and PCBs. The Walla Walla plant discharges to Mill Creek and 

the College Place plant discharges to Garrison Creek (Figure 5). The other two WWTPs in the 

basin (Dayton and Waitsburg) are small discharges (< 1 million gallons per day) located over 40 

miles up the Touchet River. As such, these plants are unlikely significant pesticide/PCB 

contributors to the Walla Walla River. Industries and other permitted facilities in the Walla 

Walla basin are not likely significant sources. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 21 

Submittal Report 

For the TMDL study, composite effluent samples were collected over a two-day period on a 

quarterly basis from the Walla Walla and College Place WWTPs. The locations of the effluent 

sampling sites are given in the TMDL technical report (see Appendix A). Sampling was done 

near the midpoint of the SPMD deployment period. Each sample was analyzed for chlorinated 

pesticides, PCBs, total suspended solids (TSS), and conductivity. 





	









	







   	






 

	


	


		





		

Figure 6. Location of Walla Walla and College Place WWTPs. 

The purpose of collecting the fish tissue samples was to 1) determine the extent to which the 

pesticides and PCBs detected in 1992-93 continue to exceed 303(d) listing criteria, 2) assess 

appropriateness of applying EPA human health criteria to the Walla Walla River, and 3) provide 

data to the Washington Department of Health (WDOH) for a human health assessment. As noted 

previously, this analysis was limited to resident mainstem species, with upper river fish being 

analyzed separately from lower river fish using the Touchet River-Dry Creek reach as an 

approximate dividing line (Figure 6). The resident species most frequently consumed from the 

Walla Walla River are smallmouth bass (Micropterus dolomieu), channel catfish (Ictalurus 

punctatus), and carp (Cyprinus carpio). The fish tissue collection for the TMDL focused on these 

species. Some segments of the local population consume almost any fish they catch, therefore 

two other commonly encountered species, bridgelip suckers (Catostomus columbianus) and 

northern pike minnow (Ptychocheilus oregonensis; formerly known as northern squawfish) were 

also collected. 
Page 22 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

 Submittal Report

Figure 7. Location of fish samples. 

Data on pesticides, PCBs, and other contaminants in migratory fish species that inhabit the Walla 

Walla River can be found in EPA’s Columbia River Basin Fish Contaminant Survey, 1996-1998 

(2002b) or online at http://yosemite.epa.gov/r10/oea.nsf . The Touchet and nearby Dry Creek 

transport most of the sediment load discharged from the basin. Inputs of sediments and 

associated contaminants from these two tributaries, as well as Pine Creek, have the potential to 

result in substantially different water quality conditions in the lower river. Therefore, separate 

specimens for chemical analysis were obtained from the upper and lower river, using the 

Touchet River-Dry Creek reach as an approximate dividing line (see Figure 6). Samples close to 

the confluence with the Columbia River were avoided in an effort to obtain data representative of 

the Walla Walla River. The fish samples were collected in July and September 2002. Fillets were 

analyzed for 303(d) listed pesticides, PCBs (Aroclor-equivalents), and percent lipids. 

Composite samples were used to obtain a cost efficient estimate of mean chemical 

concentrations. The target sample size was 20 fish of each species from each location, to be 

analyzed in composites of five fish each. At the request of the Confederated Tribes of the 

Umatilla Indian Reservations (CTUIR), several whole fish composites were included in the 

analysis. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 23 

Submittal Report 

Data Analysis 

Historical application of chlorinated pesticides to soils and crops is the primary source of these 

chemicals in rivers and streams in agricultural areas like the Walla Walla basin (e.g., Risebrough 

and Jarman, 1984; Munn and Gruber, 1997). This reservoir of contamination is supplemented by 

current-day atmospheric deposition (e.g., Wania and Mackay, 1996). Once applied or air 

deposited, chlorinated pesticides bind to soil particles. The chief means to meeting pesticide 

standards in the Walla Walla River and its tributaries is to reduce the amount of soil entering 

these water bodies and maintain low TSS levels in the water column. 

For chemical concentrations measured in the SPMD samples, pesticide concentrations in the 

Walla Walla drainage generally decreased in the following order: t-DDT (t = total) > t-chlordane 

> dieldrin >hexachlorobenzene > heptachlor epoxide. Toxaphene and PCBs were quantified less 

consistently than these other compounds, and concentrations were more variable. Upper Mill 

Creek and the upper Walla Walla River at the state line had the lowest concentrations of both 

pesticides and PCBs. The Touchet River also had a consistently low level of contamination 

relative to the Walla Walla River and other tributaries. On average, the highest t-DDT, tchlordane, and dieldrin concentrations were found in Yellowhawk Creek, 3.7, 2.7, and 3.8 ng/L, 

respectively. Maximum t-DDT and dieldrin concentrations of 6.5 and 12 ng/L (parts per trillion) 

were recorded here. The maximum t-chlordane concentration however was in Garrison Creek at 

6.4 ng/L. Dry Creek had the highest concentrations of hexachlorobenzene and heptachlor 

epoxide, averaging 1.5 and 0.6 ng/L. Large amounts of toxaphene were detected in Pine Creek, 

where concentrations up to approximately 40 ng/L were found. Creeks in the urbanized Mill 

Creek watershed had higher PCB concentrations than those that drained farming areas. The 

maximum t-PCB concentrations, 0.77 – 9.2 ng/L, were measured in Garrison Creek. Lower Mill 

Creek and Yellowhawk Creek had the second highest PCB levels, 0.54 – 1.1 ng/L for the two 

monitoring periods where PCBs were detected in these streams. 

Regarding the fish tissue sampling, DDT compounds were present in the highest concentrations 

in the fillets, followed by PCBs/toxaphene, t-chlordane, dieldrin, hexachlorobenzene, and 

heptachlor epoxide, in that order. The relative amounts of these compounds generally mirrored 

what was found in the mainstem water column. The similar chemical profile among species 

suggests a common exposure history indicative of water quality conditions in the Walla Walla 

River. Average concentrations of t-DDT ranged from 30 – 657 ug/Kg (parts per billion). T-PCB 

and toxaphene concentrations averaged 8.9 – 238 ug/Kg and 16 – 56 ug/Kg, respectively. For 

most species, the average t-DDT concentrations were 105 ug/Kg or less, and the average PCB 

concentrations 48 ug/Kg or less. Total chlordane concentrations averaged 2.7 – 19 ug/Kg. 

Dieldrin, hexachlorobenzene, and heptachlor epoxide concentrations were 2.1ug/Kg or less. The 

highest pesticide/PCB concentrations were in carp, while the lowest were in smallmouth bass. 

Pesticide and PCB concentrations in whole suckers and pike minnow were typically two to three 

times higher than the average concentration found in fillets. For bass, the whole fish sample was 

five to ten times higher than fillets. This is usually interpreted as reflecting the higher lipid (fat) 

content in whole fish as chlorinated organic compounds are preferentially soluble in lipid. 

The only compounds consistently detected in WWTP effluents were DDE, chlordane, and PCBs. 

Concentrations ranged from <0.066 – 0.11 ng/L for DDE, <0.066 – 0.20 ng/L for chlordane, and 

0.53 – 2.5 ng/L for t-PCBs. Dieldrin was also detected in one or two samples from each plant at 

concentrations of 0.21 – 0.25 ng/L. The higher PCB and chlordane levels were found in College 
Page 24 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

 Submittal Report

Place effluent. Only PCBs were detected consistently in both plants, and the levels were not 

significantly different. DDE and dieldrin concentrations were similar in each effluent. Without 

further dilution, the average t-PCB concentration in the College Place and Walla Walla effluents 

would exceed the human health criterion of 0.17 ng/L by factors of approximately 7 and 5, 

respectively. The 0.14 ng/L dieldrin criterion was slightly exceeded at both plants, but by less 

than a factor of 2. Effluent concentrations of DDE, chlordane, and the other pesticides analyzed 

were always within human health criteria. For a full description of the results of Ecology’s 

TMDL evaluation, refer to the TMDL technical report (Appendix A). 

The National Research Council (2001) has suggested using statistical regression of a water 

quality indicator on one or more predictor variables as a simple and useful model for developing 

TMDLs. This study was able to correlate total DDT with TSS and set instream targets for TSS 

reduction to meet DDT criteria for aquatic life. TSS was, in turn, linked to the state turbidity 

standard and to fish habitat requirements. In the present study, pesticide, TSS, and turbidity data 

were obtained on 88 water samples from the Walla Walla drainage. These data were examined to 

determine how pesticide concentrations vary with TSS and turbidity. The analysis focused on 

4,4’-DDE (a product of DDT breakdown) since this was the compound most consistently 

quantified in the samples. Other pesticides of concern are generally present at lower levels than 

DDE and exceed the limits of their criteria to a lesser degree. There was a strong positive 

correlation between DDE and TSS concentrations in all parts of the watershed. Land use changes 

directed at meeting DDE based target would also effectively address other problem pesticides 

identified in this report. However, because DDE occurs in association with its parent compound 

4,4’-DDT and co-metabolite 4,4’-DDD, the target must be adjusted to account for the total 

amount of DDT compounds in the water column. The SPMD data show that the relative amounts 

of DDT, DDE, and DDD in the Walla Walla mainstem and tributaries are fairly constant, with 

DDE accounting for 50 ± 4 percent of the t-DDT (Figure 28). Therefore the DDE-based TSS 

target of 100 mg/L should be reduced to 50 mg/L to meet a t-DDT criterion (divide by a factor of 

2). Additivity is appropriate since these compounds have the same or similar criteria and the 

same toxic endpoints and modes of action. 

All four samples from the East Little Walla Walla River exceeded the DDE criterion at TSS 

concentrations between 6 - 38 mg/L (1 mg/L = 1 part/million), much lower than in other 

samples. DDT compounds, dieldrin, and heptachlor epoxide were all unusually high in the East 

Little Walla Walla, based on grab samples. DDE concentrations in Yellowhawk Creek were at or 

close to the criterion at TSS concentrations of 18 – 29 mg/L. Yellowhawk also had the highest 

t(total)-DDT, t-chlordane, and dieldrin concentrations in the SPMD samples. These results 

suggest DDT and other chlorinated pesticides were applied in these two watersheds at higher 

rates or for a longer period of time than elsewhere in the drainage. Since the other pesticides of 

concern are generally present at lower levels than DDE and exceed their criteria to a lesser 

degree, land use changes directed at meeting a DDE-based target would also effectively address 

these chemicals. 

Turbidity is easier to monitor than TSS and because state standards for turbidity already exist, 

turbidity was selected as a surrogate measure of TSS where sampling both TSS and turbidity is 

not practical (Johnson, pers comm., 2005). The turbidity criteria are based on the relative change 

above background. For Class A waters (Chapter 173-201A-030-2 WAC): “Turbidity shall not 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 25 

Submittal Report 

exceed 5 NTU1 over background turbidity when the background turbidity is 50 NTU or less, or 

have more than a 10 percent increase in turbidity when the background is more than 50 NTU.” 

For this TMDL background, turbidity for the Walla Walla River was based on turbidity 

measurements taken at the state line and for Yellowhawk Creek background was based on 

measurement taken from Mill Creek at Seven Mile Road. State water quality standards allow that 

it may be necessary to use background conditions of a neighboring or similar watershed as the 

reference condition. Also turbidity at these sites was low most of the year during the 2002-2003 

TMDL evaluation; therefore, it was reasonable to use these data. 

The criteria do not set a maximum acceptable turbidity level based on beneficial use 

considerations, but they do limit the effect of an identified source on raising the turbidity in the 

receiving water. 

Background conditions are further defined in Washington’s water quality standards as “. . . the 

biological, chemical, and physical conditions of the water body, outside the area of influence of 

the discharge under consideration” except in headwaters where “. . . it may be necessary to use 

the background conditions of a neighboring or similar watershed . . .” (Chapter 173-201A-020 

WAC). 

There is no long-term record on background turbidities in the Walla Walla River that can be used 

for a comparison to standards. The historical TSS data indicate that violations of the Class A 

turbidity standard are routine in the lower river. The turbidity data obtained for the upper and 

lower Walla Walla River in the present study were compared to the turbidity equivalent to a 5 

NTU increase over the upper river. These results show that the river was in violation of 5 NTU 

allowable increase during most of the winter and spring of 2002-2003 (65 percent of samples). In 

light of chronic violations of the turbidity standard and the link between turbidity and TSS, a 

regression equation was developed for these two parameters in the Walla Walla drainage. The 

resulting equation was Turbidity = 0.80 x TSS0.87 (R2

 = 0.92). This equation was used to 

calculate turbidity levels that corresponded to the TSS targets for t-DDT. 

Because of the difficulty in measuring low levels of PCBs in surface waters, TSS and turbidity 

targets could not be derived specifically for PCBs in the Walla Walla River and its tributaries. 

However, PCBs, like chlorinated pesticides, have a strong affinity for soil particles, so it is 

thought that meeting the TSS/turbidity targets in the Walla Walla drainage will also reduce PCB 

concentrations in the river and its tributaries. The water quality targets proposed for pesticides 

would also hopefully result in the state human health criterion for PCBs being met. For further 

details, please refer to the TMDL technical report (see Appendix A). The concentration of PCBs 

detected in the effluent of the Walla Walla and College Place WWTPs exceeded human health 

criteria (see Applicable Criteria) and therefore Garrison Creek and Mill Creek were assigned 

specific wasteload and load allocations for PCBs. These are discussed further in the wasteload 

and load allocation section of this document. 

 

1

 nephelometric turbidity units 
Page 26 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

 Submittal Report

Loading Capacity 

Loading capacity is the maximum amount of a pollutant that can be delivered to a water body 

and still achieve water quality standards. Loading capacity can be calculated by multiplying 

streamflow by the pollutant water quality standard. EPA recommends using the long-term 

harmonic mean flow for carcinogens, since the adverse impacts are realized over a lifetime of 

exposure (EPA, 1991). The harmonic mean is preferable to the arithmetic mean (the ‘average’) 

for analysis of sets of numbers which are defined in relation to some unit, for example, speed 

(distance per unit time). The arithmetic mean overstates the amount of dilution available over the 

long-term, and it is long-term fish consumption that is ultimately of most importance in meeting 

human health criteria. The harmonic mean is always less than the arithmetic mean. 

The harmonic mean is calculated by dividing the number of values by the sum of the reciprocal 

of each value. For most rivers and streams, the harmonic mean is one-to- three times the 7-day, 

10-year low-flow (EPA, 1991). 

As an example, loading capacities were calculated for the Walla Walla mainstem using the 

harmonic mean. Table 4 shows estimates of the Walla Walla River’s loading capacity for 

chlorinated pesticides and PCBs, based on the harmonic mean calculated from the flow record 

for the lower river (USGS gage near Touchet, 1951 – 2002). The loading capacity for chlorinated 

pesticides ranges from 0.012 – 0.070 grams/day (1 gram = 0.035 ounces). For PCBs, the loading 

capacity is 0.014 grams/day. 

Table 4. Loading Capacity for Chlorinated Pesticides and PCBs in the Lower Walla Walla River 

(@ 34 cubic feet per second- harmonic mean flow). 

Chemical 

Human Health 

Water Quality Criteria 

(ng/L) 

Loading 

Capacity 

(grams/day)

4,4'-DDT 0.59 0.049 

4,4'-DDE 0.59 0.049 

4,4'-DDD 0.83 0.069 

t-DDT 0.59* 0.049 

Chlordane 0.57 0.047 

Dieldrin 0.14 0.012 

Hexachlorobenzene 0.75 0.062 

Heptachlor Epoxide 0.10 0.008 

Toxaphene 0.2** 0.017 

Total PCBs 0.17 0.014 

* In the Walla Walla DDT, DDE, and DDD are interrelated in that DDE and DDD occur chiefly as a result of the 

breakdown of DDT. There are no human health criteria for t-DDT, but because the individual breakdown 

compounds have the same modes of action and toxic endpoints in humans, this TMDL applied the DDT and DDE 

human health criteria of 0.59 ng/L to t-DDT.

** In the case of toxaphene, the chronic freshwater aquatic life criteria were used instead of the human health 

criteria as this is the most stringent standard. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 27 

Submittal Report 

Loading capacities based on the harmonic mean are appropriate for situations where contaminant 

concentrations vary inversely with flow, as in the case of discharge of WWTP effluent to a river. 

However, in the Walla Walla, the critical season for chlorinated pesticides, PCBs, and TSS is 

during the winter and spring when flows are elevated. Therefore, a different approach is needed 

to determine the loading capacity for TSS, which is being used as a surrogate water quality target 

in this TMDL. The 90th percentile high flow was used to assess loading capacity for TSS. The 

remaining ten percent was allocated for natural generation of sediment and turbidity. At the 90th

percentile, TSS concentrations would be expected to exceed loading capacity no more than ten 

percent of the time. Estimated TSS loads during critical season, 90th percentile flows were 

compared to the loading capacity. The loading capacities at the TSS targets for the Walla Walla 

mainstem and the East Walla Walla River and Yellowhawk Creek are shown in Tables 5 and 6 

respectively. 

 Table 5. Loading capacities for the Walla Walla mainstem and tributaries (except for the East Little 

Walla Walla River and Yellowhawk Creek) at the 50mg/L and 30mg/L TSS targets. 

Water Body Loading Capacity (lbs/day) 

@ 50mg/L TSS Target @ 30 mg/L TSS Target 

Upper Walla Walla R. 120,000 69,000 

Lower Walla Walla R. 450,000 270,000 

Garrison Creek 4,320 2,592 

West Little Walla Walla 1,566 940 

Mill Creek 47,790 28,674 

Dry Creek 19,440 11,664 

Mud Creek 1,620 972 

Pine Creek 16,470 9,882 

Touchet River 202,500 121,500 

Gardena Creek 2,160 1,296 

The data collected in Ecology’s technical evaluation found higher pesticide concentrations in the 

East Little Walla Walla River and Yellowhawk Creeks than in the rest of the Walla Walla 

drainage. Therefore, more stringent TSS targets are deemed necessary to achieve compliance 

with state water quality standards (see the load allocation section). TSS reductions down to 

5mg/L are deemed necessary to achieve compliance with the toxics criteria. 

Table 6. Loading Capacities for the East Little Walla Walla River and Yellowhawk Creek 

at the 30mg/L, 15mg/L and 5mg/L TSS targets. 

Water Body Loading Capacity (lbs/day) 

@ 30 mg/L TSS Target @ 15 mg/L TSS Target @ 5 mg/L TSS Target 

East Little Walla Walla 15,000 N/A* 380 

Yellowhawk Creek 15,000 7,600 2,500 

* The 15 mg/L TSS Target applies only to Yellowhawk Creek and is necessary to achieve compliance with Class A 

turbidity standards for the Mill Creek drainage. 
Page 28 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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The load reductions that appear to be needed in the mainstem lower river can be summarized in 

Table 7 as follows: 

Table 7. Recommended load reductions in the mainstem Lower Walla Walla River. 

Estimates of Loading Reductions Needed in the Mainstem Lower 

Walla Walla River To Meet Water Quality Targets and Goals for 

TSS 

Time 

Period 

@ 50mg/L 

TSS Target 

@ 30 mg/L 

TSS Target 

@ 5 mg/L 

TSS Goal 

January - June 74% 84% 97% 

July - December 0% 20% 86% 

Calculations indicate that no load reductions would be needed in Oregon in order for the Walla 

Walla River to meet either the 50 mg/L or 30 mg/L targets at the state line (see the load 

allocation section). TSS reductions on the Oregon side would be called for to attain a 5 mg/L 

goal. Under this goal scenario, very large TSS reductions would be needed basin-wide in both 

Washington and Oregon. 

The Walla Walla and College Place wastewater treatment plants (WWTP) were evaluated as 

sources of chlorinated pesticides, PCBs, and TSS to Mill and Garrison creeks, respectively, 

where they discharge. The only compounds consistently detected in the final effluents were 

DDE, chlordane, and PCBs. Without further dilution, total PCB concentrations violated the 

human health criterion at both facilities. However, a comparison of loading estimates suggests 

that the WWTPs represent less than ten percent of the PCB load in the receiving waters and thus 

are not as important relative to nonpoint sources and background in these watersheds. Regardless 

these still represent point sources of PCBs; therefore, it is still necessary to set wasteload 

allocations for them in this TMDL. TSS concentrations in the effluents are limited through their 

NPDES permits. Discharge monitoring reports on file with Ecology show these facilities are not 

significant TSS sources. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 29 

Submittal Report 

Load and Wasteload Allocations 

The ultimate goal of this water clean-up plan is the achievement of the human health water 

quality criteria as shown in Table 8 (with the exception of Toxaphene where the aquatic life 

criteria are used as they are most stringent). These criteria form the basis for the load and 

wasteload allocations to follow and are the focus of the remedial implementation targets and 

strategies employed in this TMDL 

Table 8. Applicable Washington State Water Quality Criteria* for Chlorinated Pesticides and PCBs 

(ng/L; parts per trillion) as the basis for the load and wasteload allocations and TSS targets. 

Chemical Water and Fish 

Consumption 

4,4'-DDT 0.59 

4,4'-DDE 0.59 

4,4'-DDD 0.83 

Total DDT** 0.59 

Dieldrin 0.14 

Heptachlor 0.21 

Heptachlor epoxide 0.10 

Hexachlorobenzene 0.75 

Chlordane 0.57 

Toxaphene*** 0.2 

PCBs 0.17 

*WAC 173-201A-040 (1997 version http://www.ecy.wa.gov/programs/wq/swqs/wac173201a1997.pdf) EPA promulgated the human health criteria for Washington in 40 CFR 131.36 

**In the Walla Walla DDT, DDE, and DDD are interrelated in that DDE and DDD occur chiefly as a 

result of the breakdown of DDT. There are no human health criteria for t-DDT, but because the individual 

breakdown compounds have the same modes of action and toxic endpoints in humans, this TMDL 

applied the DDT and DDE human health criteria of 0.59 ng/L to t-DDT. 

*** The freshwater chronic aquatic life criteria are used as they are most stringent. 

TSS targets of 50 mg/L and 5mg/L in the Walla Walla mainstem and its tributaries, and the East 

Little Walla Walla and Yellowhawk Creeks respectively are set to achieve compliance with 

Washington State human health criteria. The state's human health criteria for surface waters were 

issued to Washington by EPA in the National Toxics Rule (40CFR131.36). These criteria are the 

legally enforceable human health-based criteria used as control targets in TMDLs and other 

regulatory activities. In addition to the targets based on the human health-based criteria, this 

TMDL also provides water quality goals based on local fish consumption rates that can be used 

to inform future pollution control activities in the area. These goals address the higher 

risk/hazard that the tribes and other consumers incur as a result of their higher rates of fish 

consumption. 
Page 30 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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The secondary TSS target of 30 mg/L is set to achieve compliance with the state Class A 

turbidity standard in the Walla Walla River, East Little Walla Walla River and Yellowhawk 

Creek. Using an EPA approved procedure, a turbidity target of 15 NTU was calculated for the 

Walla Walla River downstream of the state line, which equates to a TSS target of 30mg/L. 

The load/wasteload allocations established here-in for TSS/turbidity were designed to control the 

following parameters: 4,4’-DDT, 4,4’-DDE, Chlordane, Dieldrin, Heptachlorepoxide, 

Hexachlorobenzene, and Toxaphene. 

Load Allocation 

Load allocations, which include a margin of safety, are the nonpoint source reductions that need 

to be achieved in each segment of the river for the loading capacity to be met. In this TMDL 

evaluation, TSS is proposed as a surrogate measure for chlorinated pesticides. Equivalent targets 

are provided for turbidity. Achieving the TSS/turbidity targets should also address the PCB 

listings in the drainage, with the exception of Yellowhawk, Garrison, and Mill creeks for which 

separate load allocations are made. 

This TMDL evaluation did not attempt to differentiate between TSS loading from nonpoint 

sources and background TSS in Washington. Therefore, 100 percent of the TSS loading capacity 

is allocated to nonpoint TSS sources and background TSS. The load allocation for the lower 

Walla Walla River for the initial 50 mg/L target is 450,000 pounds per day. Nonpoint and 

background sources in Oregon contribute an unknown part of the TSS load to the East Little 

Walla Walla River, West Little Walla Walla River, Pine Creek, and Mud Creek via their upper 

watersheds. The entire TSS loading capacity of the Walla Walla River at the state line is 

allocated to nonpoint sources and background in Oregon. The river’s load allocation at the state 

line for the initial 50 mg/L TSS target is 120,000 pounds per day. The TSS target of 50mg/L 

corresponds to the state’s water quality standard (based on human health criteria) for a DDT 

concentration of 0.59 mg/L. The 30 mg/L target is based on meeting background turbidity for the 

water bodies. Table 9 shows the load allocations for the Walla Walla mainstem and its tributaries 

except for the East Little Walla Walla River and Yellowhawk Creek. Table 10 shows the load 

allocations for the East Little Walla Walla River and Yellowhawk Creek. Although these 

allocations will apply year round, Ecology’s technical study has identified January to June as the 

critical period for compliance. The remedial activities suggested in this report are focused on 

achieving compliance during the critical season, but they are expected to show improvements 

year round. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 31 

Submittal Report 

Table 9. Load allocations for the Walla Walla mainstem and tributaries, except for the East Little Walla 

Walla River and Yellowhawk Creek. 

(Detailed sample site locations are given in the TMDL technical report, see Appendix A.) 

Load Allocation (lbs/day) 

Location @ 50 mg/L 

TSS Target 

@ 30 mg/L 

TSS Target 

Upper Walla Walla R. @ Peppers Bridge 120,000 69,000 

Lower Walla Walla R. @ Cummins Bridge 450,000 270,000 

Garrison Creek 4,320 2,592 

West Little Walla Walla 1,566 940 

Mill Creek 47,790 28,674 

Dry Creek 19,440 11,664 

Mud Creek 1,620 972 

Pine Creek 16,470 9,882 

Touchet River 202,500 121,500 

Gardena Creek 2,160 1,296 

Table 10. Load allocations for the East Little Walla Walla River and Yellowhawk Creek. 

(Detailed sample site locations are given in the TMDL technical report, see Appendix A.) 

Load Allocation (lbs/day) 

Location @ 30 mg/L 

TSS Target 

@ 15 mg/L 

TSS Target 

@ 5 mg/L 

TSS Target 

East Little Walla Walla River 15,000 N/A* 380 

Yellowhawk 15,000 7,600 2,500 

* The 15mg/L Target applies only to Yellowhawk Creek and is necessary to achieve compliance with Class A 

turbidity standards for the Mill Creek drainage. 

Washington State’s human health criteria for DDT compounds and other toxins are based on an 

average lifetime fish consumption rate of 6.5 grams per day. Since it is believed that most tribal 

members consume fish at higher rates than the average fish consumer, state standards may not be 

adequately protective of tribal members and other individuals with high rates of fish 

consumption. Table 11 shows fish consumption rates for Columbia River Intertribal Fish 

Commission (CRITFC) member tribes – Umatilla Confederated Tribes, Yakama Nation, Warm 

Springs Tribe, and Nez Perce Tribe as determined in a CRITFC (1994) fish consumption study. 

Table 11. Fish Consumption Rates of CRITFC Member Tribes and Approximate Fish Meals per Month. 

Population Fish Consumption 

Rate (g/day) 

Approximate Fish 

Meals Per Month** 

General Public – average consumer 6.5* 1 

Tribal Members – average consumer 63 8 

General Public – high consumer 142 19 

Tribal Members – high consumer 389 51 

* Washington State standard 

**assuming 8 ounces (roughly 227 grams) per fish meal and 30 days per month 
Page 32 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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In order to address tribes’ concerns Ecology decided to add additional TSS goals2 that could be 

used in future pollution control activities to address the higher risk/hazard that the tribes and 

others incur as a result of their higher fish consumption rates. The EPA recently conducted a 

health risk assessment for people eating fish from the Columbia River basin (EPA, 2002). Using 

the values the EPA selected in that study, additional numerical TSS goals were developed to 

protect tribal members and members of the general public with high rates of fish consumption in 

the Walla Walla basin. Those seeking further detail on the EPA study and tribal members’ 

consumption rates should refer to EPA 2002. Table 12 shows the t-DDT concentrations and their 

corresponding TSS targets and goals. 

Table 12. TSS targets/goals and corresponding t-DDT concentrations for the protection of average and 

high fish consumers among the general public and tribal members. 

TSS 

Estimated Water 

Column 

t-DDT 

Concentration 

Population Subgroup 

Addressed 

50 mg/L Target 0.59 ng/L State Standard: General Public – 

30 mg/L Target 0.44 ng/L State Standard: Turbidity* 

5 mg/L Goal** 0.059 ng/L Tribal Members – average fish consumer 

2 mg/L Goal** 0.024 ng/L General Public – high fish consumer 

1 mg/L Goal** 0.012 ng/L Tribal Members – high fish consumer 

 * The turbidity target was based on the state turbidity standard for Class A water bodies (Chapter 173-

201A-030-2 WAC). 

 ** These appear as ‘targets’ in Ecology’s TMDL technical report. See footnote below. 

Ecology’s Walla Walla TMDL technical study found that monitoring data indicated an additional 

TSS target needed to be set for meeting the Class A turbidity standard in the Walla Walla River. 

Using an EPA approved procedure for the lower Yakima River TMDL, a turbidity target of 15 

NTU was calculated for the Walla Walla River downstream of the state line, which equates to a 

TSS target of 30mg/L. The 30 mg/L target was added to the other TSS targets to ensure 

compliance with state turbidity standards. For further details on the derivation of the turbidity 

target and the regression equation used to calculate the corresponding TSS target refer to 

Ecology’s Walla Walla chlorinated pesticides and PCBs TMDL technical study (Appendix A). 

As shown, the approach adopted in this TMDL was specifically designed to not only meet the 

load allocations that address state toxicity standards, but also to address state turbidity standards. 

Additional goals are provided in the study that can be used to inform the development of future 

water quality targets that specifically address high fish consumers in the Walla Walla basin. 

Table 13 summarizes the calculated numerical water quality targets and goals for the Walla 

Walla River drainage - except for the East Little Walla Walla River and Yellowhawk Creek. 

 

2

 In Ecology’s Walla Walla chlorinated pesticide and PCBs TMDL technical report, these ‘goals’ appear as ‘targets’. 

This report reserves the use of the term ‘target’ for those limits derived from State water quality standards. As the 

more stringent limits are not based on State standards they do not have the same regulatory significance, and are 

thus referred to as ‘goals’ here. Please see Ecology’s response to the CTUIR’s comments in Appendix H for further 

details. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 33 

Submittal Report 

Table 13. Water quality targets for the Walla Walla River drainage. 

(Excluding the East Walla Walla River and Yellowhawk Creek.) 

TSS Turbidity 

Target Effect of Meeting the Target 

50 mg/L Target 24 NTU 

• achieves compliance with human health water quality 

criteria for chlorinated pesticides 

• addresses average fish consumers among the general public 

• provides a moderate level of habitat protection 

30 mg/L Target 15 NTU • achieves compliance with the Class A turbidity standard 

5 mg/L Goal* 3 NTU • addresses average tribal fish consumers 

• provides a high level of habitat protection 

2 mg/L Goal* 1 NTU • addresses high fish consumers among the general public 

1 mg/L Goal* <1 NTU • addresses high fish consumers among tribal members 

 * These appear as ‘targets’ in Ecology’s TMDL technical report. See footnote 2 on previous page. 

The same approach used for the Walla Walla mainstem was used for the East Walla Walla River 

and Yellowhawk Creek. However, more stringent TSS/turbidity targets are recommended for the 

East Walla Walla River and Yellowhawk Creek specifically, because higher concentrations of 

the chemicals addressed in this report are found here relative to the rest of the Walla Walla 

drainage. Therefore, the 50mg/L TSS target employed for the Walla Walla mainstem is deemed 

not to be protective enough of water quality standards for these water bodies. The 30 mg/L TSS 

target is still applicable as it is necessary to ensure protection of state turbidity standards. 

However a more restrictive target is needed for Yellowhawk Creek to meet turbidity standards. 

Present survey data show that turbidity in Yellowhawk Creek should be at or below 8 NTU, 

which equates to a TSS concentration of 15mg/L. 

A TSS 5 mg/L: 3 NTU turbidity target for the East Little Walla Walla River and Yellowhawk 

Creek should protect average fish consumers among the general public. The data collected 

indicate that TSS/turbidity levels that would address higher rates of fish consumption among the 

general public and tribal consumers approach zero for these two water bodies and so are not 

proposed as goals at this time. This effort would best be initiated after some water quality 

improvements have been realized, at which point the relationship between TSS, turbidity, and 

trace-level pesticide contamination may be more easily and accurately discerned. Those seeking 

more detail on how NTU and TSS targets were calculated for the East Walla Walla River and 

Yellowhawk Creek should refer to Ecology’s Walla Walla TMDL technical study (Appendix A). 

Table 14 shows water quality targets recommended specifically for the East Little Walla Walla 

River and Yellowhawk Creek. 
Page 34 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Table 14. Water Quality Targets for the East Walla Walla River and Yellowhawk Creek. 

TSS Turbidity Target Effect of Meeting the Target 

5 mg/L Target 3 NTU 

• achieves compliance with human health water quality 

criteria for chlorinated pesticides 

• addresses average fish consumers among the general 

public 

• provides a high level of habitat protection 

30 mg/L Target 15 NTU 

• achieves compliance with the Class A turbidity standard 

(for mainstem Walla Walla) 

• provides a moderate level of habitat protection 

15 mg/L Target 

(Yellowhawk 

Creek) 

8 NTU 

(Yellowhawk 

Creek) 

• achieves compliance with the Class A turbidity standard 

(for Mill Creek drainage) 

Goals to protect consumers with high rates of fish consumption among the general public and tribe to 

be developed at a later date. 

In order to meet the water quality standards at issue in this TMDL, it is recommended that the 

targets be applied to the Walla Walla River and its tributaries at the state line and at the mouths 

of all tributaries to the mainstem in Washington. Each tributary is a natural water body with 

fisheries and aesthetic resource values deserving of protection, and the targets protect these 

values. 

A phased approach should be adopted for meeting the targets, starting with the 30 mg/L:15 NTU 

target in the East Little Walla Walla River and Yellowhawk Creek and the 50 mg/L:24 NTU 

target in other parts of the drainage. The 50 mg/L:24 NTU target is overprotective for chlorinated 

pesticides in the Touchet River. The target retains its value for habitat protection and meeting the 

turbidity standard nonetheless. For the East Little Walla Walla River and Yellowhawk Creek, the 

ultimate 5 mg/L:3 NTU target is overprotective for habitat and turbidity, but appears necessary 

to meet pesticide standards. Initially, the targets should be applied directly to all irrigation returns 

and other potential or probable sources at the point they enter the mainstem or tributaries. This is 

the simplest and most equitable approach. The focus of remedial actions in this TMDL is largely 

on agricultural lands because firstly, most land use in the Walla Walla Basin is agricultural, and 

secondly, the chemicals addressed in this TMDL have historically been applied primarily in 

agricultural areas. In addition, it is impractical to set water quality targets tailored for each 

individual return. Monitoring data from the tributaries coupled with knowing where BMPs are 

and are not being implemented can guide later sampling efforts for irrigation returns. Once water 

quality improvements become realized and TSS/turbidity targets are progressively achieved, it 

may be appropriate to develop different targets for the returns. 

The 2 mg/L:1 NTU and 1 mg/L:<1 NTU goals imply exceptional water quality conditions and 

would be difficult to achieve in an agricultural basin like the Walla Walla. Because they were 

extrapolated to equate to t-DDT concentrations below the detection limit, there is a substantial 

amount of uncertainty in their accuracy. Once erosion and TSS levels are reduced, sediments 

may possibly carry a lower amount of pesticides and so the goals (based on the current 

relationship be pesticides and TSS) may have to be reevaluated as shown in the Yakima toxin 

TMDL. The appropriateness of these values should be re-assessed once the more easily achieved 

targets are met. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 35 

Submittal Report 

Wasteload Allocation 

Wasteload allocations are point source reductions needed in each segment of the river for the 

loading capacity to be met. This TMDL evaluation did not attempt to differentiate between TSS 

loading from point sources, nonpoint sources, and background in Oregon. No significant TSS 

point sources to the Walla Walla River and its tributaries are present or anticipated in Oregon. 

Therefore, wasteload allocations are zero. 

No significant point sources of TSS are present or anticipated in the Washington portion of the 

Walla Walla watershed. Wasteload allocations are therefore zero here as well, with the exception 

of the Walla Walla and College Place WWTPs. National Pollutant Discharge Elimination 

System (NPDES) permits limit the amount of TSS that can be discharged by the College Place 

and Walla Walla WWTPs (wastewater treatment plants). The current limits state that the average 

monthly effluent concentrations for TSS “shall not exceed 15 mg/L or 15 percent of the 

respective monthly average influent concentrations, whichever is more stringent.” Discharge 

monitoring reports on file with Ecology show that the Walla Walla and College Place WWTPs 

are insignificant sources of TSS to the receiving waters. Adjustments to the NPDES permits for 

these WWTPs are not necessary at this time, and TSS allocations should be consistent with 

permit load limits. 

Wasteload and load allocations were assigned for PCBs in Garrison Creek and Mill Creek in 

light of the levels detected in the College Place and Walla Walla WWTP effluents. The 

wasteload allocations for PCBs identified in this report shall be added to the NPDES permits for 

the WWTPs of Walla Walla and College Place once the TMDL detailed implementation plan 

(DIP) is completed. Nonpoint sources coming into the WWTPs may be contributing to elevated 

PCB levels found in the WWTP effluent. Future remedial actions directed at nonpoint sources 

may help to alleviate the PCB problem in the WWTP’s discharge. The WWTP wasteload 

allocations were calculated as the product of the human health water quality criterion and the 

NPDES permit limit for the average monthly effluent flow. The remaining loading capacity of 

these streams was allocated to nonpoint sources. (There is no natural background for PCBs.) In 

addition to Mill and Garrison creeks, Yellowhawk Creek3

 was also found to be impaired for 

PCBs and was therefore assigned a load allocation. However, because no point source has yet 

been identified in this tributary, no wasteload allocation for PCBs has been assigned. Further 

monitoring is needed to determine what (if any) point sources of PCBs exist on Yellowhawk 

Creek. If point sources are identified, they should be addressed through future NPDES or 

stormwater permits. The PCB wasteload and load allocations for Garrison Creek and Mill Creek, 

and the load allocation for Yellowhawk Creek are shown in Table 15 below. 

 

3

 Yellowhawk was not assigned a PCB allocation in Ecology’s Walla Walla toxics TMDL technical report as the 

TSS targets set to address chlorinated pesticides in the drainage were originally deemed sufficient to address the 

non-point PCB problem as well. However, the EPA expressed concern over this approach as the correlation between 

TSS and PCBs was weaker than that for chlorinated pesticides. Therefore Ecology made the decision to assign 

additional PCB allocations to all exceedances not already covered under those for Garrison and Mill Creeks. 

Evaluation of Ecology’s 2002-2003 sampling data showed that the only remaining PCB exceedance that needed to 

be addressed was that for Yellowhawk Creek. 
Page 36 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Table 15 Wasteload and Load allocations for PCBs in Garrison Creek, Mill Creek, and Yellowhawk Creek. 

Wasteload and load allocations for 

PCBs (gm/day) 

Garrison 

Creek 

Mill 

Creek 

Yellowhawk 

Creek 

Wasteload allocation for WWTP 0.0011 0.0062 

Load allocation for nonpoint 0.0017 0.023 0.010 

Loading capacity 0.0028 0.029 0.010 

It is recommended that the Walla Walla and College Place WWTPs work closely with Ecology 

to develop practical and cost effective management plans to reduce PCB concentrations in their 

effluent. These plans should be professionally designed and include a detailed monitoring and 

management strategy for determining the sources of PCB contaminate in the WWTPs’ service 

area and identifying possible remedial actions. In addition, such plans should include detailed 

WWTP effluent monitoring to assess whether implementation is successful. Ecology and 

representatives of the WWTPs have already held a preliminary meeting to begin to address 

issues related to the PCB problem and have committed to further meetings following publication 

of the submittal report. Through consultation with Ecology, it should be possible to set interim 

wasteload targets and determine an appropriate and cost effective effluent sampling strategy. 

Ecology will give technical and financial assistance wherever possible, to ensure the remedial 

strategies are effective in reducing PCB levels in accordance with the wasteload allocations 

assigned in this TMDL. 

It is probable that urban stormwater runoff is an additional contributing source of chlorinated 

pesticides and PCBs in the basin. Although the sources of PCB impairment in Yellowhawk 

Creek have as yet not been identified, it is possible that stormwater runoff from the city of Walla 

Walla may be contributing to the problem. Because stormwater runoff was not specifically 

studied in Ecology's chlorinated pesticide and PCB TMDL evaluation study, sufficient data are 

not available with which to set allocations for stormwater runoff at this time. The detailed 

implementation plan (DIP) for this TMDL will include a monitoring plan that may help 

determine future stormwater allocations, and will identify those corrective measures necessary to 

address chlorinated pesticides and PCBs in storm water. Until data are available, Walla Walla 

County, Columbia County, and the cities of Walla Walla and College Place, should develop and 

implement programmatic activities to control sediment concentrations in their stormwater runoff. 

Specifically, it is recommended they adopt ordinances or other regulatory mechanisms to require 

stormwater runoff controls at construction sites and post-construction stormwater controls for 

development projects, train staff to review development site plans and perform site inspections, 

and adopt an operation and maintenance plan that incorporates practices to reduce suspended 

solids in runoff from their municipal operations. 

These jurisdictions should refer to the Stormwater Management Manual for Eastern Washington

(2004) and Model Municipal Stormwater Program for Eastern Washington (2003) and review 

their current stormwater management ordinances and municipal practices to determine whether 

they are adequately protective of surface water quality (see Appendix C and D). Where enhanced 

stormwater quality management needs are identified, specific recommendations will be provided 

by Ecology. These jurisdictions must also carry out any legally mandated responsibilities with 

regard to stormwater management, including adherence to the requirements of any future 

NPDES Permits issued to them. Moreover, they may possibly be required to seek coverage under 

the Eastern Washington Phase II NPDES Permit for Municipal Stormwater Discharges. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 37 

Submittal Report 

Stormwater permit holders should be in compliance with applicable quality assurance project 

plan (QAPP) as part of such compliance. Furthermore the permit holders may be required to 

submit a TMDL summary implementation report detailing the status and actions taken by the 

permit holder to implement the TMDL. 

Margin of Safety 

A margin of safety is required in a TMDL to account for uncertainty in understanding the 

relationship between pollutant discharges and water quality impacts. This TMDL evaluation 

incorporates several procedures and assumptions that confer a safety margin. 

• Two methods were used to derive the TSS concentration on which the water quality 

targets were based, thereby increasing confidence in the appropriateness of the targets. 

• The additive effects from the combined concentrations of DDT, DDE, and DDD were 

accounted for by basing the water quality targets on t-DDT. Basing targets on t-DDT 

rather than DDE, DDE, and DDT individually is more protective of water quality than 

what strict adherence to the individual criteria calls for. 

• Although it was not feasible to set PCB allocations for all tributaries, a loading capacity 

for PCBs in the Walla Walla River was based on a conservative assumption for 

calculating flow (harmonic mean). The harmonic mean is preferable to the arithmetic 

mean here as the arithmetic mean overstates the amount of dilution available over the 

long-term, and it is long-term fish consumption that is ultimately of most importance in 

meeting human health criteria. 

• A watershed drainage area approach to load and wasteload allocation should be 

protective of individual tributaries. 

• A t-DDT target provides a wider margin of safety for other chlorinated pesticides, since 

these are generally present at lower concentrations relative to criteria. 

• Ecology’s TMDL evaluation found the levels of chlorinated pesticides, PCBs, and total 

suspended solids in the Walla Walla River are highest during winter and spring when the 

runoff is highest. Therefore, the loading capacity was calculated based on flows during 

this period, rather than the period of lowest flow as is often the case. In this way, the 

loading capacity set in this report should be most protective of water quality in the 

drainage. 

• The 90th percentile statistic was used in developing the turbidity target and assessing 

loading capacity. This approach implicitly allocates ten percent of the load to natural 

generation of suspended sediment and turbidity. 

• The recommended approach of applying the water quality targets directly to tributaries 

and drains gives a wider margin of safety than requiring only the minimal water quality 

improvements needed to meet standards in the mainstem. 

• A phased approach for implementing the targets/goals is proposed; the ultimate 

targets/goals are conservative. 
Page 38 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Several sources of uncertainty could not be resolved with the information currently available. 

• Because of difficulties in analyzing trace amounts of PCBs in surface water and a lack of 

information on sources, it is uncertain exactly how the decrease in PCB concentrations 

will track with the proposed water quality targets and at what point in the cleanup process 

standards will be achieved. 

• As already described, there is uncertainty in the accuracy of the 2 mg/L:1 NTU and 

1 mg/L:<1 NTU water quality goals, and the appropriateness of these values should be 

reassessed once the more easily achieved targets are met. 

• Because estimated toxaphene concentrations exceeded t-DDT levels in Pine Creek, 

meeting water quality targets for TSS in this creek may not result in toxaphene meeting 

standards. Source investigation is recommended. 

Finally, this study did not investigate the bottom sediments in the Columbia River backwater 

formed in the lower ten miles of the Walla Walla River by McNary Dam. This area is a likely 

sink for chlorinated pesticides and PCBs associated with particulates transported by the 

Walla Walla River and a potential source of contamination to fish. Sediment recovery will occur 

as upstream water quality targets are met, but the time for recovery is unknown. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 39 

Submittal Report 

Summary Implementation Strategy 

Introduction 

A summary implementation strategy (SIS) is needed to meet the requirements of a TMDL 

submittal for approval as outlined in the 1997 Memorandum of Agreement between the U.S. 

Environmental Protection Agency and the Washington State Department of Ecology. Its purpose 

is to present a clear, concise, and sequential concept of how the waters covered in the TMDL 

will achieve water quality standards. The SIS includes an outline of how a more detailed 

implementation plan will be developed, those implementation activities that are planned or 

already underway, a strategy for developing follow-up monitoring plans, a summary of public 

involvement methods, and potential funding needs and sources to make implementation of the 

plan a reality. 

A TMDL advisory group was formed in early 2005 to guide the development of this report. At 

the time of writing this report, groups currently represented in the advisory group include: the 

Walla Walla County Watershed Planning Department, Walla Walla WRIA 32 Planning Unit, 

Gardena Farms Irrigation District; Walla Walla Watershed Alliance; Whitman College; Walla 

Walla Community College; Walla Walla County Planning Commission; the Walla Walla County 

Health Department; Confederated Tribes of the Umatilla Indian Reservations; Kooskoskie 

Commons; Washington State University Cooperative Extension program; city of College Place; 

and city of Walla Walla. The rest of the advisory group is made up of local private landowners 

representing a variety of interests from across the basin. 

There are several other important organizations working in the Walla Walla region that are 

currently not serving on the advisory group but their assistance in the development of this TMDL 

is appreciated. These groups include Washington Department of Fish and Wildlife, Walla Walla 

County Conservation District, Columbia Conservation District, and the Natural Resource 

Conservation Service. Efforts have been made to encourage representatives of these groups to 

serve at future advisory group meetings. In addition, representatives from the Oregon 

Department of Environmental Quality and the Oregon based Walla Walla Watershed Basin 

Council have been contacted and encouraged to attend future advisory group meetings to foster 

cross-border relations and to ensure coordination of implementation activities across 

administrative boundaries. It is proposed that representatives from these groups will not serve as 

official advisory group members because of jurisdictional conflicts. There is currently a high 

level of cooperation and communication between advisory group participants, and their 

continued participation in the TMDL process and assistance in later implementation phases of 

the project is appreciated. 

Implementation Overview 

The strategy to implement the TMDL is based upon the continuation of the many existing efforts 

already underway throughout the watershed to reduce suspended sediment in project area 

waterways. Point sources will be addressed by adherence to discharge limits set in Ecology’s 

NPDES permits. The nonpoint sources (load allocations) will be addressed by the use of BMPs 

and education. The principal focus of the TMDL will be to continue the implementation of 

seasonal and year-round BMPs to prevent the entry of sediment into area water bodies. 
Page 40 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Additionally, continued monitoring of implementation activities and water quality is essential in 

assessing the progress of the TMDL. 

The goal of this TMDL is to reduce chlorinated pesticides and PCBs in the Walla Walla River 

and its tributaries so that levels meet water quality standards. Table 16 shows the recommended 

interim and final timelines for the achievement of water quality targets/goals set in this report. 

The timelines shown are meant to represent number of years after completion of the detailed 

implementation plan (DIP). 

Table 16. Timelines for the achievement of interim targets and state water quality standards 

Number of Years Walla Walla River Mainstem East Walla Walla and Yellowhawk 

from end of DIP TSS Target/Goal Turbidity 

Target/Goal 

TSS Target Turbidity Target 

5 50mg/L 24 NTU 30mg/L 15 NTU 

10 30mg/L 15 NTU 15mg/L 8 NTU 

15 5mg/L 3 NTU 5mg/L 3 NTU 

20 2mg/L-1mg/L 1 to < 1 NTU <5mg/L: developed later 

A detailed implementation plan (DIP) will be prepared within a year following EPA’s approval 

of the TMDL submittal report. Ecology will work closely with the TMDL Advisory Group, and 

other local entities to implement the TMDL and develop the DIP. The DIP will identify 

specifically how, when, and where voluntary restoration activities will be implemented. A 

detailed monitoring plan will also be developed. Ecology and other entities will provide technical 

assistance and seek additional funding for these restoration activities and monitoring. 

Implementation Activities 

This report acknowledges and is appreciative of the many federal, state, local governmental, and 

non-governmental agencies that have already sponsored or implemented a variety of 

conservation activities that may have helped to partially alleviate the toxin problem addressed in 

this TMDL. However, the results of Ecology’s TMDL evaluation indicate that further action is 

needed if state water quality standards are to be met. To this end, it is necessary to identify 

available resources and devise future implementation actions. Also, an effectiveness monitoring 

strategy needs to be planned as a key component of an adaptive management process essential to 

a successful TMDL. This section will discuss these issues in detail. 

As stated earlier, Ecology’s TMDL evaluation of chlorinated pesticides and PCBs in the Walla 

Walla River concluded that a reduction of total suspended solids (TSS) in the water column was 

the chief means to meeting water quality targets for these chemicals. A recent report by 

Economic and Engineering Services, Inc.(EES, 2003) identified a number of sources of sediment 

including road-building and logging activities in the upper reaches of tributaries, recreational 

vehicle use, and urban runoff. They concluded, however, that “given the predominance of 

agricultural land use in the watershed, agricultural practices have been identified as the principal 

source of fine sediment,” a conclusion supported by Ecology’s TMDL evaluation. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 41 

Submittal Report 

The preliminary draft of the Walla Walla Watershed Plan, January 2005 (Appendix B) shows a 

table of voluntary Watershed Planning management actions. Many of these actions would serve 

to reduce the TSS levels of toxins addressed in this TMDL and are reproduced here (Table 17). 

As stated in the Walla Walla Watershed Plan, no organization or person is required to take on a 

commitment without their consent. However, once an organization has formally agreed to 

implement actions identified in the plan, it is expected these commitments be honored; 

recognizing funding limitations. The watershed plan does not create any obligations for private 

businesses, citizens or landowners. However, there are actions identified for voluntary action in 

the private sector. Although the Watershed Planning and TMDL processes are fundamentally 

different, Ecology has and will continue to seek opportunities for collaboration and cooperation 

between the two processes. It should be noted that Ecology is required under the federal Clean 

Water Act to conduct TMDLs and ensure clean water. 

Table 17. Summary of management goals for the Walla Walla chlorinated pesticides and PCBs TMDL. 

Management Category Project Type 

1. Prevent/Mitigate Forest Practices Impacts 

Activities on forested lands can have significant impacts on water quality, particularly as they 

relate to forest practices, soil erosion and water temperature. Protection of forested headwater 

drainages is critical as a source of high quality water for downstream reaches, which support a 

variety of beneficial uses 

1a. Improve Forest Road/Trail Management • Management of forest roads 

• Design of forest roads/culverts 

• Construction practices for forest roads 

• Erosion control for forest roads 

• Decommissioning of forest roads/trails 

• Road fill evaluation 

• Road density evaluation 

1b. Improve timber Harvest Management • Evaluation of unstable slopes 

• Timber harvest management plans 

• Road and timber harvest buffers 

• Restoration of riparian recreation areas 

• Soil compaction mitigation 

1c. Other Watershed Actions • Watershed assessments 

• Coordinated resource management plans 

• Water quality monitoring 

2. Prevent/Mitigate Agricultural Impacts 

Nonpoint chlorinated pesticide and PCB sources are varied in the Walla Walla, but are primarily 

related to historically applied agricultural chemicals. Ongoing efforts by the Washington State 

Dept. of Ecology working with the Conservation Districts, NRCS, Irrigation Districts, and local 

water users to reduce nonpoint source impacts are already successfully addressing some of these 

problems. 

2a. Improve Irrigation Water Management • Irrigation district system improvement 

• Irrigation scheduling and management 

• On-farm irrigation system 

Upgrades/conversion 

• On-farm sediment ponds 

• Off-farm sediment ponds 

2b. Improve Cropland Management • In-furrow residue placement 

• Row crop erosion control 

• Tillage management 
Page 42 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Management Category Project Type 

2c. Reduce Impacts of Agricultural Chemicals • Pesticide application training 

• Pesticide licensing programs 

• Row crop soil erosion controls 

• Irrigation water management 

• Deep percolation evaluations 

2d. Address Livestock Impacts • Maintain Technical/Financial Support to 

Confined Animal Feeding Operations 

(CAFO); NPDES Permitting of CAFOS 

• Voluntary fencing of streams and buffer 

strips near streams 

• Small landowner assistance programs 

• Application of public land grazing 

programs 

• Manure management 

• Support conservation district efforts 

regarding dairies 

2e. Control Other Agricultural Impacts • Roadside spraying evaluations 

• Aquatic weed control evaluations 

• Silt removal from canals/laterals 

• Canal weed control impacts 

• Pesticide residue monitoring in aquatic 

life 

• Agricultural soil monitoring for 

pesticides 

• Educational and assistance programs for 

small farm/ranches 

• Educational tours/demonstrations for 

commercial growers 

• Consider water quality impacts in routine 

operations and maintenance of irrigation 

canals 

3. Prevent/Mitigate Stormwater Impacts 

Stormwater runoff from developed and urban areas and industrial sites contains pollutants that 

impact receiving waters. State and regional guidelines exist (e.g., Eastern Washington’s 

Stormwater Guidelines) to identify appropriate stormwater management practices. Stormwater 

ordinances have been adopted by county governments and other municipalities in the Walla Walla 

River Basin. 

3a. Plan/Implement Municipal Stormwater 

Runoff Controls 

• Municipal stormwater ordinances 

• Regional stormwater runoff control 

guidelines 

• Municipal stormwater control plans 

• Regional stormwater impact assessments 

• Urban/suburban land use awareness 

programs transportation/de-icing 

guidelines 

3b. Plan/Implement Industrial Stormwater 

Runoff Control 

• Industrial stormwater ordinances 

• Regional industrial stormwater 

guidelines 

• Industrial stormwater control plans 

• Regional stormwater impact assessments 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 43 

Submittal Report 

Most forestry operations are likely to occur on lands on the Oregon side of the Walla Walla 

drainage as most forestry lands in the basin are located there. These are beyond the jurisdiction 

of the Washington State Department of Ecology. Ecology’s TMDL evaluation concluded that 

activities on the Oregon side of the border were relatively minor contributors to the toxin 

problem in the Walla Wall basin. However, it may still be necessary to address these Oregon 

sources in order to meet the most stringent TMDL water quality targets/goals. It is anticipated 

that existing programs under the state’s forest and fish regulations, DNR’s Habitat Conservation 

Plan (HCP), and the federal government’s Northwest Forest Plan will provide the regulatory 

framework needed in this regard. 

There has been considerable attention in recent years to reducing water quality impacts from 

agriculture on the region's waterways. Existing permit programs and voluntary measures to 

address water quality concerns should continue to be used. Advisory agencies such as the 

Washington State University (WSU) Cooperative Extension, the Walla Walla County 

Conservation District, and the Columbia Conservation District are available to offer technical 

and financial assistance with landowners’ efforts. The Walla Walla Watershed Plan suggests that 

total sediment loading can be reduced by 85 percent by using no-till practices instead of 

historical cropping practices involving significant tillage operations. In recent years, irrigators 

have made great strides towards reduced suspended sediment and pesticide levels in area 

waterbodies, and will continue to implement best management practices (BMPs) in these areas to 

meet TMDL targets. This plan recommends that planning decisions be focused toward land 

practices that decrease susceptibility to erosion. 

Because stormwater runoff was not specifically studied in Ecology's chlorinated pesticide and 

PCB TMDL evaluation study, sufficient data are not available with which to set allocations for 

stormwater runoff at this time. Until data are available, Walla Walla County, Columbia County, 

and the cities of Walla Walla and College Place must carry out any legally mandated 

responsibilities with regard to stormwater management, including adherence to the requirements 

of any future NPDES permits issued to them. These jurisdictions should refer to the Stormwater 

Management Manual for Eastern Washington (2004) and Model Municipal Stormwater Program 

for Eastern Washington (2003) and review their stormwater management ordinances and 

municipal practices to determine whether they are adequately protective of surface water quality 

(see Appendix C and D respectively). Where enhanced stormwater quality management needs 

are identified, specific recommendations will be provided by Ecology, possibly including a 

requirement to seek coverage under the Eastern Washington Phase II NPDES Permit for 

Municipal Stormwater Discharges. 

Because urban and suburban household materials are potential sources of nonpoint pollution, 

educational programs focused on the proper use and disposal of household hazardous materials 

should be advertised and offered to the public. These programs should increase urban and 

suburban residents’ awareness about how household hazardous materials should be used and the 

implications of misuse. Household hazardous materials are herbicides, pesticides, and cleaning 

agents, as well as automotive and light industrial fluids that are commonly present in the home or 

on a farm. 
Page 44 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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The following items were identified by the Walla Walla TMDL advisory group which will be 

looked at during the development of the Detailed Implementation Plan (DIP): 

Several TMDL program implementation topics have emerged that warrant emphasis in the water 

quality strategy for the TMDL implementation plan. It is the desire of several members of the 

TMDL Advisory Committee that these site specific issues be discussed in more detail during the 

Detailed Implementation Plan (DIP) development. Further public input will be sought to help 

prepare this plan. The plan will identify how, when, and where voluntary restoration activities 

will be implemented. 

Actions recommended in the DIP are intended to be specific enough to clearly identify the 

actions and results; yet general enough to permit some flexibility in carrying them out. It is 

recognized that some actions will require further investigation prior to full implementation. 

Additionally it is recognized that some actions can be carried out only if funding is provided by 

the State Legislature or other funding agencies, and that funding decisions will be made over a 

period of months or years following plan adoption. 

The following concepts will be looked at in further detail during the Detailed Implementation 

Plan development: addressing the correlation between TSS and Turbidity to toxins in the 

Touchet River basin and the Dry Creek basin; identifying historic background levels for turbidity 

in the Walla Walla watershed and various tributaries, including identification of additional 

sampling sites including soil testing and streambed sediment loads; identifying additional 

sampling methods; identification of geographic source differences for toxin contamination 

including possible atmospheric deposition. As long as TSS continues to be the surrogate 

measure of chlorinated pesticides periodic validation of the current formulas should be made. 

Many local interests in the Walla Walla Basin are involved with TMDL planning and 

implementation. During the development of the DIP, in areas where soils contributing to 

turbidity are found to have high levels of pollutant present, special emphasis on helping to 

relieve the problem will be employed. Ecology will continue to work closely with these basin 

interests to address outstanding issues. 

Table 18 lists the possible entities that may use the general implementation actions to meet the 

targets in this TMDL. The information listed in the table is part of an overall strategy and will 

likely change as personnel and monetary resources are better defined during the development of 

the DIP. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 45 

Submittal Report 

Note: Please refer to the list of acronyms and abbreviations (Appendix G) for further assistance 

with Table 18. 

Table 18. Organization of TMDL entities and their contributions. 

Entity Responsibilities to be met 

TMDL advisory group Review progress of implementation strategy 

Ecology Manage the TMDL process, provide guidance 

and support to other agencies 

Homeowners with waterfront property Avoid actions that will cause streambank 

destabilization or erosion or will otherwise add 

sediment to area waterways 

Irrigation Entities (Districts and Companies) Where possible improve irrigation efficiencies, 

upgrade diversions and, where appropriate, 

implement BMPs to prevent entry of suspended 

sediment into area waterways 

Irrigators Implement appropriate BMPs to prevent entry 

of sediment-laden agricultural return flows into 

area waterways 

Columbia Conservation District (CCD) and 

Walla Walla County Conservation District 

(WWCCD) and Ecology 

Continue to fund agricultural BMP 

implementation: controlling agricultural runoff, 

reducing suspended sediment in drains and 

tributaries, preventing streambank 

destabilization and erosion. 

CCD, WWCCD, WSU Cooperative Extension, 

Kooskooskie Commons 

Extend outreach efforts and technical 

assistance to agricultural producers (irrigators, 

livestock managers, others) in the watershed 

CCD and WWCCD Continue to monitor water quality of the 

watershed’s surface water (as possible, given 

funding availability) 

Walla Walla and Columbia County 

governments, and Walla Walla, College Place, 

Waitsburg and Dayton City governments. 

Administration of stormwater discharge, 

Critical Area Ordinances and shoreline master 

programs 

Walla Walla and Columbia County 

governments and WSDOT 

Continue to maintain roads and roadside 

ditches to prevent entry of sediment into area 

waterways 

Private and state timber owners Implement forest management practices as 

required by Forests and Fish rules 

Ranchers Implement livestock management BMPs to 

prevent streambank destabilization and erosion 

US Forest Service (USFS) Implement forest management practices as 

required by the Memorandum of Agreement 

with Ecology 

Ecology Review if interim targets have been met after 

deadlines reached, and if not, devise an 

alternative action plan 

Ecology,TMDL advisory group Evaluate if the water quality samples at points 

of compliance meet the interim and final 

targets 
Page 46 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Entity Responsibilities to be met 

Ecology, TMDL advisory group. If interim target was not met, develop new 

action plans to meet target 

Ecology, WWCCD and CCD, TMDL advisory 

group 

Determine changes in monitoring sites, tests, or 

frequency are needed 

Ecology, WWCCD, CCD, WSU cooperative 

extension, Kooskooskie Commons, TMDL 

advisory group 

Review program and frequency for accuracy 

Ecology, TMDL advisory group Review if final TMDL targets have been met, 

and if not, identify new timeline and BMPs 

needed. 

Cities, Walla Walla and Columbia county 

governments, and WSDOT 

Identify and implement stormwater 

management plans with any Stormwater 

Permits issued by the Department of Ecology 

and/or refer to Ecology’s eastern Washington 

stormwater manual for guidance on general 

stormwater management 

Walla Walla and College Place WWTPs Monitor and maintain chlorinated pesticides 

and PCBs wasteload set in NPDES permits and 

the TMDL 

Reasonable Assurances 

The ultimate goal of this TMDL is to meet the chronic aquatic toxicity and human health criteria 

for chlorinated pesticides and PCBs. Maintaining the TMDL goals will be required once 

compliance has been achieved. Improved water quality will be achieved through the combined 

efforts of all basin stakeholders. Local involvement and commitment to chlorinated pesticide 

and PCB problems in the Walla Walla River watershed are substantial and are evidenced by the 

dedication of the people and organizations involved in the development of this plan. To support 

this TMDL, Ecology will work cooperatively with all basin stakeholders to promote the 

implementation of activities contained in this plan. 

This water cleanup plan, its TMDL targets, and the associated implementation activities listed in 

the plan are not in themselves enforceable. However, Ecology is obligated to implement the 

approved TMDL. Organizations and their commitments under laws, rules, and programs to 

resolve chlorinated pesticide and PCB problems in the watershed are described below. 

Washington State Department of Ecology: Ecology has been delegated authority under the 

federal Clean Water Act by the U.S. EPA to establish water quality standards, administer the 

NPDES wastewater permitting program, and enforce water quality regulations under Chapter 

90.48 RCW. Ecology responds to complaints, conducts inspections, and issues NPDES permits 

as part of its responsibilities under state and federal laws and regulations. In cooperation with 

conservation districts, Ecology will pursue implementation of BMPs for agricultural and other 

land uses and may use formal enforcement, including fines, if voluntary compliance is 

unsuccessful. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 47 

Submittal Report 

The Ecology/Conservation District MOA: Ecology has a Memorandum of Agreement (MOA) 

with conservation districts, signed in 1988, that allows Ecology to refer agriculture-related water 

quality complaints to the conservation districts for resolution of the problems. (However, 

Ecology will investigate and seek resolution of all complaints that appear to need immediate 

action.) Conservation Districts have authority under Chapter 89.08 RCW to develop farm plans 

to protect water quality and provide animal waste management information, education, and 

technical assistance to residents on a voluntary basis. When a complaint is referred to a 

conservation district by Ecology, the conservation districts will meet with the owner/operator of 

the property where the violation occurred, assist the owner/operator in the development of a 

water quality management plan, provide technical assistance to complete the plan and monitor 

plan implementation, notify Ecology regarding the owner/operator’s willingness to correct the 

problem and successful implementation of the water quality management plan, and annually 

submit to Ecology a formal summary of progress on referred water quality violations. While 

Ecology maintains lead enforcement responsibility for resolution of the referred complaints, this 

MOA expedites and streamlines correction of agricultural water quality violations. 

The TMDL Advisory Group: A TMDL advisory group was formed to direct and support 

development of the Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily 

Load Submittal Report. In such capacity, the advisory group may make suggestions for 

modifications to the TMDL report. The majority of members of the advisory group are key 

community members with interests in compliance, and who promote the success of 

implementation. The group is a highly functional group and is dedicated to meeting the goals of 

the TMDL. 

State of Oregon DEQ: Since approximately a quarter of the Walla Walla basin lies in Oregon, 

the implementation work underway in Oregon has the potential to positively affect water quality 

in the Washington portion of the river. As is the case in Washington, the water quality standards 

program in Oregon is a joint effort between the Department of Environmental Quality (DEQ) 

and the EPA. DEQ is responsible for developing and enforcing water quality standards that 

protect beneficial uses such as drinking water, coldwater fisheries, industrial water supply, 

recreation, and agricultural water supply. The EPA develops regulations, policies, and guidance 

to help Oregon implement the program and to ensure that Oregon's adopted standards are 

consistent with the requirements of the Clean Water Act and relevant regulations. The EPA has 

authority to review and approve or disapprove state standards and, where necessary, to 

promulgate federal water quality rules. DEQ has the authority and the responsibility to ensure 

that TMDLs are completed and submitted to EPA. Although no TMDLs are being developed for 

chlorinated pesticides and PCBs in Oregon, a TMDL is in progress for temperature. It is thought 

that many of the actions recommended to reduce temperature problems (e.g., riparian restoration 

and re-vegetation) may also help to reduce sediment loads from soil erosion. 

Regulatory Programs: there are a number of local, state, and federal regulatory programs that are 

already in existence which can be expected to help reduce the chlorinated pesticide and PCB 

problem in the Walla Walla River and its tributaries. Local regulatory programs include: land use 

planning/permitting and its associated programs, including Critical Areas Ordinances and 

Shoreline Master Programs which are administered by county and city governments. 

State regulatory programs: Discharge permits, including stormwater discharge, impact 

water quality through management of erosion and suspended sediment and other 

pollutants. Ecology recently completed a stormwater management manual for eastern 
Page 48 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Washington which is designed to guide local authorities as to how best to meet new 

stormwater discharge regulations. More specifically, Ecology is in the process of 

developing general stormwater discharge permits for various cities in the Walla Walla 

basin. When these are finalized, they will help regulate the stormwater component of the 

chlorinated pesticide and PCB problem. Other state regulatory programs include wetland 

protection programs, the implementation of forest practices that minimize water quality 

impacts under RCW 76.09, the enforcement of Shoreline Management legislation and 

general environmental review under the SEPA. 

Federal regulatory programs: The Safe Drinking Water Act (SDWA) contains provisions 

related to surface and groundwater quality including required monitoring of public water 

systems and requirements for development of Wellhead Protection Plans. 

A unique settlement agreement was reached in 2000 between the three largest irrigation 

districts (Walla Walla River, Hudson's Bay Improvement and Gardena Farms) and the 

USFWS. This agreement (and its extension signed in 2001) dictated increased instream 

flows to be maintained in the Walla Walla River. These efforts are intended to improve 

temperature conditions and increase habitat connectivity and may help reduce sediment 

loads in turn reducing levels of toxins in the water column though this is yet to be 

determined. A bi-state habitat conservation plan (HCP) is being developed as a follow up 

on activity to the settlement agreement, and includes other parties such as the city of 

Walla Walla 

Non-Regulatory Programs: In addition to the regulatory programs in place, there are local, state, 

and federal non-regulatory programs that may also have beneficial impacts on the chlorinated 

pesticide and PCB problem. Local non-regulatory programs include conservation district, 

Natural Resource Conservation Service (NRCS), and WSU Cooperative Extension Programs 

designed to reduce erosion and sediment loading to surface waters, improve water quality 

monitoring, or vegetate riparian areas. Conservation districts have authority under Chapter 89.08 

RCW to develop farm plans to protect water quality and provide animal waste management 

information, education, and technical assistance to residents on a voluntary basis. Also, county 

governments are involved in water quality improvements in a variety of programs including, but 

not limited to, applying for state grants on behalf of landowners. 

State non regulatory programs: State management of several funding programs is 

designed to assist various parties in improving water quality. These programs include the 

Centennial Clean Water Fund, Washington State Water Pollution Control Fund, Clean 

Water Act Section 319 Nonpoint Source Fund, and participation in Conversation Reserve 

Enhancement Program (CREP) (state obligation ten percent). The Washington 

Department Fish and Wildlife (WDFW) manages the Watershed Recovery Project that 

involves collecting information about land use practices and water quality within 

watersheds. The information is collected into a usable format to assist watershed 

managers to prioritize improvements programs. Also there are various forestry easement 

programs described in the Department of Natural Resources (DNR) Forest Practices 

Rules (WAC 222). 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 49 

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Federal Non-Regulatory Programs: The U.S. Department of Agriculture (USDA) - 

Natural Resources Conservation Service (NRCS) and USDA Farm Service Agency 

(FSA) administers programs such as the Conservation Reserve Program (CRP), 

Conservation Reserve Enhancement Program CREP, the Continuous Conservation 

Reserve Program (CCRP), the Environmental Quality Incentives Program (EQIP), the 

Wildlife Habitat Incentives Program (WHIP), the Grassland Reserve Program (GRP), and 

the Wetlands Reserve Program (WRP). 

Comprehensive Irrigation District Management Plan (CIDMP): The executive committee of the 

Irrigation Districts’ Guideline development process, in collaboration with CTUIR and various 

other stakeholders, recently completed a manual (Comprehensive Irrigation District Management 

Plan) that sets up a voluntary and incentive-based process for improving irrigation district 

operations in response to the Endangered Species Act and the Clean Water Act. Specifically, the 

manual describes an innovative and assertive approach to water quality problem assessment, 

monitoring, outreach, BMP implementation, and adaptive management. Many of the activities 

outlined in this manual may have potential beneficial impacts on the sediment load and toxin 

problem in the Walla Walla River. 

The United States Forest Service(USFS)/Ecology MOA: In 2000, the USFS – Region 6 and 

Ecology signed a Memorandum of Agreement (MOA) addressing protection of water quality on 

federal forest lands in Washington State. As part of the required actions under this MOA, the 

USFS is actively working to maintain and improve roads that may cause the entry of sediment 

into area waterways. The USFS has also developed several programs to restore damaged riparian 

areas and to educate the public regarding respect for rivers and riparian areas. All of these efforts 

will directly support this TMDL and help to ensure its success. 

Besides the general assurances listed above, there are a host of specific water quality 

enhancement activities already completed or underway in the Walla Walla basin that are helping 

to meet TMDL chlorinated pesticide and PCB targets. These activities are summarized in 

Table19. 

Table 19. Miscellaneous existing projects related to water quality improvement in WRIA 32. 

(Taken from the preliminary draft of the Walla Walla Watershed Plan, January 2005 – see Appendix B.) 

Project Lead Agency Duration Comments 

Couse Creek riparian 

enhancement (OR) 

CTUIR (BPA funded) 1996-1998 

Stream flow 

enhancement 

WWRID, GFID,HBIC, 

USFWS 

1999-2002 

Upland restoration 

planning 

NRCS, WDFW Ongoing 

Implementation of 

conservation tillage 

Landowners/Conservation 

Districts/NRCS/WSU 

Extension 

Ongoing 

Installation of other onfarm BMPs Landowners, WWCCD, 

CCD, NRCS, WSU 

Extension 

Ongoing Included installation of 

terraces, sediment 

basins, and vegetated 

filter strips; enrollment 

of landowners in CRP 

& CREP 
Page 50 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Project Lead Agency Duration Comments 

Riparian buffer 

restoration (CREP & 

others) 

Landowners, NRCS, 

CTUIR (BPA funds), FSA 

& Conservation Dists. 

Ongoing Areas like the South 

Fork Patit and Blue 

Creek 

Various riparian and 

instream restoration 

projects 

Landowners, NRCS, and 

Tri-state Steelheaders 

Ongoing 

College Place stream 

restoration & 

City of College Place 1998-2001 Along Garrison Creek 

Treatment 

wetland/WWTP 

Improvements 

City of College Place Ongoing 

Walla Walla WWTP 

improvements 

City of Walla Walla 1999-2000 Various improvements 

Dayton WWTP 

improvements 

City of Dayton 1999-2000 

Waitsburg WWTP 

improvements 

City of Waitsburg 2001-2001 Various improvements 

and new construction 

Household hazardous 

waste collection 

Ecology, Landowners, City 

and County Agencies 

Ongoing 

Livestock removal Landowners, NRCS Ongoing Remove direct stream 

access for livestock 

and reduce total 

livestock presence 

Irrigation efficiency Landowners and 

City/County Agencies 

Ongoing 

Forest practices Landowners and 

City/County/State Agencies 

Ongoing Reduces upland 

erosion 

Increasing industrial 

chemical control and 

accountability 

Ecology, Landowners, 

Business, City and County 

Agencies 

Ongoing 

Adaptive Management 

Adaptive management has been defined in state law as “reliance on scientific methods to test the 

results of actions taken so that the management and related policy can be changed promptly and 

appropriately” (RCW 79.09.020). It may be described as a cycle that occurs in four stages: (i) 

identification of information needs, (ii) information acquisition and assessment (monitor), (iii) 

evaluation and decision-making (evaluate), and (iv) management action or response (respond). 

Oftentimes, the first and fourth stages can be considered as one, since part of the response to 

newly evaluated data may be to identify new information needs. Thus, the key stages of the 

adaptive management cycle are to “monitor”, “evaluate”, and “respond.” Adaptive management 

is a continuing attempt to reduce the risk arising from the uncertainty associated with 

information used to develop the management actions. Generally speaking, each stage of the cycle 

has an associated uncertainty that should decrease through each completed cycle of the process. 

This is one perspective to applying adaptive management. An alternative way to look at adaptive 

management is to consider it as “experimental management” wherein the management actions 

taken are used to test key hypotheses and assumptions used to develop the management actions. 

There are subtle differences in application, but conceptually they are similar in that adaptive 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 51 

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management attempts to address uncertainty in information. In this TMDL, adaptive 

management specifically refers to a process whereby the advisory group and Ecology devise new 

implementation strategies in the event that monitoring shows targets are not being met. A 

feedback loop is implemented consisting of the following three steps. 

Step 1. The water quality improvement plan and associated action items are 

implemented. Programs and on-site BMPs are evaluated for technical 

adequacy of design and installation. 

Step 2. The effectiveness of the water quality improvement plan in achieving the goal 

and objectives is evaluated by comparison to water quality monitoring data. If 

the goal and objectives are achieved, the implementation efforts are adequate 

as designed, installed, and maintained. If not, the plan is modified and 

objectively reevaluated. 

Step 3. Project success and accomplishments should be publicized and reported to 

continue project implementation and support. 

Where new (not previously identified) sources of suspended sediment bearing chlorinated 

pesticides and PCBs are discovered, they will be remedied through the appropriate jurisdiction. 

If or when planned implementation activities are not producing expected or required results, 

Ecology or other entities may choose to conduct additional studies to identify the significant 

sources of toxin input to the river system. If the causes can be determined, additional 

implementation measures may be needed. If the shortfall does not have an apparent cause (e.g., 

everyone is implementing required BMPs and all potential sources have been addressed, but 

targets are not being met), then more studies may be required. Conversely, should water quality 

standards be met prior to achieving the specific target allocations outlined here, the purpose of 

this TMDL shall be satisfied. Re-evaluation of the status of this TMDL will be conducted every 

five years. For non-federal forested areas, the agreements in the forests and fish report 

incorporate adaptive management as needed to ultimately meet state water quality standards. The 

USFS also has a policy of adaptive management. 

Regular monitoring is essential to ensure successful implementation of an adaptive management 

strategy. The monitoring strategy is discussed in detail below. 

Monitoring Strategy 

The EPA calls for a monitoring plan for TMDLs where implementation will be phased over time. 

The monitoring is conducted to provide assurance that the control measures will meet the TMDL 

targets and achieve water quality standards. Long-term monitoring will be important to ensure 

fulfillment of the Walla Walla River TMDL for chlorinated pesticides and PCBs. Ecology is the 

lead agency for monitoring the implementation activities and will coordinate with the appropriate 

watershed entities to accomplish these efforts. 

A distinction should be made here between implementation monitoring and effectiveness 

monitoring. Implementation monitoring can begin at any time and is usually more dispersed and 

on a larger scale than effectiveness monitoring. Because the cost of sampling toxin 

concentrations directly on the scale required in this phase of monitoring will probably be 

prohibitive, TSS and/or turbidity will be used here as surrogate measures of toxicity. The goal of 
Page 52 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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implementation monitoring is to pinpoint the most significant sources of contamination. 

Effectiveness monitoring is conducted five years after completion of the detailed implementation 

plan (DIP) and its primary purpose is to determine whether implementation activities have been 

put into effect and whether the water body is in compliance with state water quality standards. 

Unlike implementation monitoring, effectiveness monitoring typically requires assessing toxin 

concentrations directly using SPMDs and fish tissue samples. 

A TMDL must include monitoring to measure achievement of targets and water quality 

standards. NPDES permits require point sources to regularly monitor their discharge effluent. 

Monitoring data from the Walla Walla and College Place WWTPs will be included with data 

collected as part of a general monitoring strategy for watershed. The goal of monitoring would 

be to determine if BMPs are effective in reducing TSS loading to the Walla Walla River and 

bringing the river into compliance with standards. Objectives should include 1) obtaining 

accurate and representative data on TSS and turbidity in the mainstem Walla Walla River and 

major tributary sources of TSS, 2) using the data to assess progress toward meeting water quality 

targets, 3) re-surveying fish and the water column to verify that human health standards for 

chlorinated pesticides and PCBs are being met, 4) re-assessing the accuracy of the 2 mg/L:1 

NTU and 1 mg/L:<1 NTU targets for the mainstem, and 5) developing water quality targets to 

protect high fish consumers in the East Little Walla Walla River and in Yellowhawk Creek. 

The Walla Walla Watershed Planning Unit developed a sediment model using the SWAT (Soil 

Water Assessment Tool) model in their efforts to assess the positive impact of alternative 

agricultural BMPs implemented in the basin (EES., 2003). The model was used to analyze the 

erosion and sediment characteristics of the basin as impacted by historical and current (or 

projected) agricultural practices. Both the planning unit and Ecology have access to this model 

and it could be further developed to conduct a basin wide modeling study or to focus on specific 

drainage areas within the basin. In addition, the model could be used to help evaluate the stream 

loading associated with other water quality parameters individually or as affected by sediments. 

Water quality monitoring should begin with collecting one year of baseline data on TSS and 

turbidity at the ten sites listed below. Sampling should be conducted at least twice weekly, 

similar to what is being done for effectiveness monitoring in the Yakima TMDL. In order to 

obtain representative and comparable data, depth integrating sampling procedures should be 

used. Streamflow should be measured. 

The following sampling sites are suggested for TMDL effectiveness monitoring: 

1. Walla Walla River @ state line 

2. Yellowhawk Creek 

3. East Little Walla Walla River 

4. Garrison Creek 

5. Mill Creek 

6. Dry Creek 

7. Pine Creek 

8. Touchet River 

9. Gardena Creek 

10. Lower Walla Walla River @ Cummins Bridge 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 53 

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Once BMPs have been implemented, twice-weekly samples would be collected from January 

through June, the critical period for TSS loading. The pre- and post-data for January-June would 

be tested for significant differences and the 90th percentile values compared to the numerical 

targets. January-June monitoring would continue on a yearly or less frequent basis, depending on 

results of the comparisons and pace at which land use changes proceed in the watershed. 

Monitoring in July-December would be phased in as appropriate to assess progress in meeting 

the more restrictive targets or to acquire more background data. 

As the water quality targets for TSS and turbidity are progressively achieved, chlorinated 

pesticides and PCBs should be analyzed periodically in resident mainstem fish species and the 

water column. PCBs should also be analyzed in fish samples from Mill and Garrison creeks. 

Sample size for fish should be appropriate for making a statistical comparison with criteria used 

to assess compliance with human health standards and WDOH should be consulted on the 

sampling design. Water column sampling and analysis should employ low-level techniques. 

Water samples should be focused on the mainstem and include the East Little Walla Walla River 

and Yellowhawk Creek. TSS and turbidity samples should be collected in conjunction with the 

pesticide sampling. 

A quality assurance project plan (QAPP) should be prepared for whatever monitoring is 

conducted. The QAPP should follow Ecology guidelines (Lombard and Kirchmer, 2004) paying 

particular attention to consistency in sampling and analytical methods. 

In addition to the effectiveness monitoring detailed above, it is recommended that follow-up 

monitoring work be done to answer key questions not answered in the TMDL chlorinated 

pesticide and PCB evaluation: 

• Chlorinated pesticides and PCBs should be analyzed in sediment samples from the 

Columbia River backwater in the lower Walla Walla River and an assessment made of 

potential for uptake of these chemicals by fish and of ecological risk. The rate of 

sediment deposition should be measured and results used to predict time to recovery 

under various cleanup scenarios for the upstream watershed. 

• An effort should be made to determine if there are remediable PCB sources in the Mill 

Creek watershed. More intensive sampling of Mill and Garrison creeks may help 

determine if and where localized sources exist. Other potential sources in the watershed 

include agricultural, food processing, chemical, scrap, and waste sites. 

• It is recommended that as part of a PCB management strategy the WWTPs of Walla 

Walla and College Place monitor the output of dischargers in their service areas to 

determine possible contributors of PCBs to their systems. This strategy should also 

include WWTP effluent sampling to ascertain whether remedial activities are successful 

in reducing PCB load. Ecology will provide technical assistance wherever possible. 

• Additional water sampling is required along Yellowhawk Creek in order to identify 

possible sources of PCBs. The sampling strategy will be developed in the Detailed 

Implementation Plan (DIP). No point sources were identified along the Yellowhawk 

during the TMDL technical study, but if such sources are later identified they will be 

addressed in NPDES or stormwater permits and monitored regularly to assess compliance 

with water quality standards. 
Page 54 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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• The stormwater systems of the cities of Walla Walla and College Place should be 

sampled for both chlorinated pesticides and PCBs to ascertain how much if any these are 

contributing to the problem - information which can be incorporated in future stormwater 

discharge permits. 

• Sampling should be conducted to locate toxaphene sources in the Pine Creek drainage. 

Because of the analytical challenges presented by toxaphene, some kind of preconcentration technique may be required to obtain useful data. 

Funding 

Potential funding sources available through Ecology’s water quality grants program include the 

Centennial Clean Water Fund, Section 319 grants under the federal Clean Water Act, and the 

State Revolving Fund (SRF) grants. In addition to Ecology’s funding programs, there are many 

other funding sources available for watershed planning and implementation, point and nonpoint 

source pollution management, fish and wildlife habitat enhancement, stream restoration, and 

education. Public sources of funding include federal and state government programs, which can 

offer financial as well as technical assistance. Private sources of funding include private 

foundations, which most often fund nonprofit organizations with tax-exempt status. Forming 

partnerships with other government agencies, nonprofit organizations, and private businesses can 

often be the most effective approach to maximize funding opportunities. Ecology will work with 

public entities and local interest groups to prepare appropriate scopes of work, to implement this 

TMDL, and to assist with applying for grant opportunities as they arise. 

The NRCS directs its Environmental Quality Incentives Program (EQIP). EQIP provides 

technical, educational, and financial assistance to eligible farmers and ranchers to address soil, 

water, and related natural resource concerns on their lands in an environmentally beneficial and 

cost-effective manner. The program is implemented through conservation plans that include 

structural, vegetative, and land management practices. Contracts are five to ten years long. The 

USDA FSA administers the Conservation Reserve Enhancement Program (CREP) and 

Conservation Reserve Program (CRP), both of which the NRCS has technical responsibility 

over. These are both voluntary cost share programs designed to restore and enhance habitat and 

increase bank stability along waterways on private lands. A cropping history is needed to be 

eligible for CRP but not for CREP. Marginal pasture lands are also eligible. The NRCS provides 

technical and financial assistance to eligible farmers and ranchers to address soil, water, and 

related natural resource concerns on their lands in an environmentally beneficial and costeffective manner. These programs offer payments for annual rental, signing, cost share, practice, 

and maintenance in exchange for removing land from production and grazing, under 10-15 year 

contracts. Additionally, the NRCS can initiate funding under Public Law 83-566, the Watershed 

Protection and Flood Prevention Act. This federal law can fund watershed projects that include 

watershed protection, water quality improvements, soil erosion reduction, irrigation water 

management, sedimentation control, and fish and wildlife habitat enhancement. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 55 

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The Walla Walla County and Columbia conservation districts provide cost-share programs to 

irrigators and ranchers for riparian restoration, farm programs, and irrigation conversion 

programs - all of which could help reduce sediment loads in the Walla Walla River and its 

tributaries. These conservation districts could also help to provide polyacrylamide (PAM) to 

farmers that when applied to the soil helps to reduce soil erosion. Cost-share can and should be 

sought by all cooperating groups, but it should be recognized that implementation of BMPs (with 

or without cost share) requires that individual landowners make an investment in the practice. 

Because much of the Walla Walla basin is considered critical ESA habitat for bulltrout and 

summer steelhead, state and federal funding is available for endangered fish species projects, 

which will probably help support implementation under this TMDL. The Walla Walla Watershed 

Planning Unit will have access to funding for projects that will further help ameliorate the 

conditions responsible for the chlorinated pesticide and PCB problem in the area. 

CTUIR is involved with a number of habitat, hatchery, harvest, and hydrosystem restoration 

actions that will ultimately result in increased fish production in the Walla Walla and increased 

tribal consumption of Walla Walla fish. CTUIR’s involvement in the sub basin provides 

additional opportunities for funding including but not limited to cost-matching from non-federal 

rate payer Bonneville Power Administration, EPA tribal gap, and Bureau of Indian Affairs 

money. These resources may be available to assist in on-the-ground science such as fish 

collections and toxins sampling, and are already in place to develop and implement habitat 

restoration projects that may ultimately result in decreased chlorinated pesticide levels. 

Summary of Public Involvement 

Public involvement is vital in any TMDL. Nonpoint TMDLs are successful only when the 

watershed landowners and other residents are involved, since they are the closet to and most 

knowledgeable of the watershed resources. Ecology’s TMDL Evaluation of Chlorinated 

Pesticides and PCBs in the Walla Walla River, published in October of 2004, was subjected to 

public review and comment. Much of the material in this submittal report is based on that 

publication. In early 2005, a TMDL advisory group was founded to discuss issues and make 

recommendations to Ecology in the development of this TMDL. Ecology also maintains a 

mailing list of interested parties so that information is readily available to other agencies and the 

public on matters concerning the TMDL process. The submittal report is opened to public review 

and comment before submittal to the EPA. 

The Walla Walla basin has a host of local, state, federal and tribal agencies, and nongovernmental organizations involved in conservation activities associated with the mainstem and 

its tributaries. Many private landowners in the area are also intimately involved with these 

conservation efforts. Ecology will continue to take steps to try and ensure participation and 

cooperation from all the great diversity of interested parties in this TMDL. 
Page 56 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Involving stakeholders in the basin is the key to executing management strategies and actions. 

Examples of organizations to contact in targeted outreach efforts during implementation include: 

• County Conservation Districts and Farm Bureaus. 

• Walla Walla Backyard Stream Team. 

• Washington State University Cooperative Extension. 

• Confederated Tribes of the Umatilla Indian Reservation (CTUIR). 

• Agricultural commodity groups and trade associations. 

• Environmental organizations (Blue Mountain Land Trust, CELP, American Rivers) and 

civic organizations. 

• Walla Walla Watershed Alliance, Kooskooskie Commons and Native Creek Society. 

• Walla Walla County Watershed Planning Department. 

• County Commissions and City Councils. 

• Tri-State Steelheaders and other hunting, fishing and outdoor recreation interest groups. 

• Irrigation districts and organized ditch irrigators. 

• Agri-businesses and timber companies. 

• Economic development organizations. 

• Colleges (Walla Walla Community College, Whitman College and Walla Walla 

College); and individual landowners. 

• Government agencies such DOH, WDFW, USDA-NRCS, USFS, and ODEQ and ODFW 

• Walla Walla Basin Watershed Council (in Oregon). 

• Oregon State University Cooperative Extension. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load: Page 57 

Submittal Report 

References Cited 

Butcher, Don. 2005. Personal communication between Don Butcher of the Oregon State 

Department of Environmental Quality and Donovan Gray of the Washington State Department 

of Ecology, February 2005. 

Carson, R.J. and Pogue, K.R. 1996. Flood Basalts and Glacier Floods: Roadside Geology of 

Parts of Walla Walla, Franklin and Columbia Counties, Washington, Division of Geology and 

Earth Resources Information Circular 90, Washington State Dept. of Natural Resources, 

Olympia, WA. 

CRITFC. 1994. A Fish Consumption Survey of the Umatilla, Nez Perce, Yakama, and Warm 

Springs Tribes of the Columbia River Basin. Tech. Rept. 94-3. Columbia River Inter-Tribal 

Fish Commission, Portland, OR. 

Davis, D. A. Johnson, and D. Serdar. 1995. Washington State Pesticide Monitoring Program: 

1993 Fish Tissue Sampling Report. Washington State Dept. Ecology, Olympia, WA. 

Pub. No. 95-356. 

EES. 2003. Technical Memorandum WRIA 32 – Water Quality Task 1 – Erosion and Sediment 

Modeling for the Walla Walla Basin. Final Draft Report, June 2003, Economic and Engineering 

Services Inc., Kennewick, WA. 

EPA. 1991. Technical Support Document for Water Quality-based Toxics Control. 

EPA/505/2-90-001. 

EPA. 2002. Columbia River Basin Fish Contaminant Survey, 1996-1998. EPA Region 10, 

Seattle, WA. EPA-910/R-02-006. 

Fitzpatrick, Martin. 2005. Personal communication between Martin Fitzpatrick of the Oregon 

Dept. of Environmental Quality and Donovan Gray of the Washington State Dept. of Ecology, 

April 13 2005. 

Hashim, W.A. and Stalmaster, L. 2004. Washington’s Water Quality Management Plan Control 

Nonpoint Sources of Pollution Volume 1: Water Quality Summaries for Watersheds in 

Washington State, Washington State Dept. Ecology, Olympia, WA. Publication No 04-10-063. 

HDR/EES, Inc. 2005. Walla Walla Watershed Plan, Preliminary, Draft Report, January 2005, 

HDR/EES, Inc., Pasco, WA. 

Johnson, Art. 2005. Personal communication between Art Johnson of Washington State Dept. 

of Ecology’s EAP unit and Donovan Gray of Washington State Dept. of Ecology, March 2005. 

Joy, J. and B. Patterson. 1997. A Suspended Sediment and DDT Total Maximum Daily Load 

Evaluation Report for the Yakima River. Washington State Dept. Ecology, Olympia, WA. 

Pub. No. 97-321. 

Manley, et. al. 1999 
Page 58 Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load

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Mapes, B.E. 1969. Sediment Transport by Streams in the Walla Walla River Basin, 

July 1962 – June 1965. U.S. Geological Survey, Water Supply Paper 1868. 

Munn, M.D. and S.J. Gruber. 1997. The Relationship Between Land Use and Organochlorine 

Compounds in Streambed Sediment and Fish in the Central Columbia Plateau, Washington and 

Idaho, USA: Environ. Toxicol. Chem. 16(9)1877 - 1887. 

National Research Council. 2001. Assessing the TMDL Approach to Water Quality 

Management. Water Science and Technology Advisory Board. National Academy Press, 

Washington, D.C. 

Newcomb, R.C. 1965. Geology and Ground-Water Resources of the Walla Walla River Basin, 

Washington-Oregon: Washington Division of Water Resources Water supply Bull. No. 21, 151p. 

Nicholson, Frank. 2005. Personal communication between Frank Nicholson of the City of 

Walla Walla and Donovan Gray of Washington State Dept. of Ecology, Spokane WA. 

Risebrough, R.W. and W.M. Jarman. 1984. DDT Compounds in Soils and Water Particulates 

of the Salinas Valley. A report to the State Water Resources Control Board, Sacramento, CA. 

Schirman, Roland. 2005. Personal communication between Roland Schirman of the WSU 

Cooperative Extension Unit and Donovan Gray of the Washington State Department of Ecology, 

March 29 2005. 

Walla Walla County and Walla Walla Basin Watershed Council. 2004. Walla Walla Sub basin 

Plan: May 2004 Version, prepared for: Northwest Power and Conservation Council, 84p. 

Wania, F. and D. Mackay. 1996. Tracking the Distribution of Persistent Organic Contaminants. 

Environ. Sci. Technol. 30(9):390-396A. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page A-59

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Appendix A 

A Total Maximum Daily Load Evaluation for Chlorinated Pesticides and PCBs in the 

Walla Walla River 

By Art Johnson, Brandee Era-Miller, Randy Coots, and Steve Golding 

October 2004 

Publication No 04-03-032 

This report is available on the Department of Ecology home page on the World Wide Web 

at http://www.ecy.wa.gov/biblio/0403032.html

For a printed copy of this report, contact: 

Department of Ecology Publications Distributions Office 

Address: PO Box 47600, Olympia WA 98504-7600 

E-mail: ecypub@ecy.wa.gov 

Phone: (360) 407-7472 

Refer to Publication Number 04-03-032 
Page A-60 Walla Walla River Chlorinated Pesticides and PCBs total Maximum Daily Load

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Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page B-61

Submittal Report 

Appendix B 

Walla Walla Watershed Plan 

Preliminary Draft 

By HDR/EES, Inc. 

January 2005 

This report is available on the Walla Walla Watershed Planning home page on the World Wide 

Web at http://www.wallawallawatershed.org/wsplanning.html#documents 

For a printed copy of this report, contact: 

HDR/EES, Inc. 

2805 St. Andrews Loop, Suite A 

Pasco, Washington 99301 
Page B-62 Walla Walla River Chlorinated Pesticides and PCBs total Maximum Daily Load

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Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page C-63

Submittal Report 

Appendix C 

Stormwater Management Manual for Eastern Washington 

Prepared By: The Washington State Department of Ecology’s Water Quality Program 

September 2004 

Publication No. 04-10-076 

This report is available on the Department of Ecology home page on the World Wide Web 

at http://www.ecy.wa.gov/biblio/0410076.html

If you have a credit card, you can order printed copies of the manual and the manual on CD at the 

following Internet address: 

https://wws2.wa.gov/prt/printwa/wsprt/default.asp

OR: 

For a printed copy of this report, contact: 

Department of Ecology Publications Distributions Office 

Address: PO Box 47600, Olympia WA 98504-7600 

E-mail: ecypub@ecy.wa.gov 

Phone: (360) 407-7472 

Refer to Publication Number 04-10-076 
Page C-64 Walla Walla River Chlorinated Pesticides and PCBs total Maximum Daily Load

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Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page D-65

Submittal Report 

Appendix D 

Model Municipal Stormwater Management for Eastern Washington 

Prepared By: The Washington State Department of Ecology’s Water Quality Program 

September 2003 

Publication No. 03-10-076 

This report is available on the Department of Ecology home page on the World Wide Web 

at http://www.ecy.wa.gov/biblio/0310076.html

If you have a credit card, you can order printed copies of the manual and the manual on CD at the 

following Internet address: 

https://wws2.wa.gov/prt/printwa/wsprt/default.asp

OR: 

For a printed copy of this report, contact: 

Department of Ecology Publications Distributions Office 

Address: PO Box 47600, Olympia WA 98504-7600 

E-mail: ecypub@ecy.wa.gov 

Phone: (360) 407-7472 

Refer to Publication Number 03-10-076
Page D-66 Walla Walla River Chlorinated Pesticides and PCBs total Maximum Daily Load

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Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page E-67

Submittal Report 

Appendix E 

Upper Yakima River Basin Suspended Sediment, Turbidity and Organochlorine Pesticide 

Total Maximum Daily Load, Submittal report. 

Prepared By: Jane Creech and Joe Joy 

August 2002 

Publication No. 02-10-047 

This report is available on the Department of Ecology home page on the World Wide Web 

at http://www.ecy.wa.gov/biblio/0210047.html

If you have a credit card, you can order printed copies of the manual and the manual on CD at the 

following Internet address: 

https://wws2.wa.gov/prt/printwa/wsprt/default.asp

OR: 

For a printed copy of this report, contact: 

Department of Ecology Publications Distributions Office 

Address: PO Box 47600, Olympia WA 98504-7600 

E-mail: ecypub@ecy.wa.gov 

Phone: (360) 407-7472 

Refer to Publication Number 02-10-047 
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Appendix F 

By Congressional mandate, the Agency for Toxic Substances and Disease Registry (ATSDR)

produces "toxicological profiles" for hazardous substances found at National Priorities List 

(NPL) sites. These hazardous substances are ranked based on frequency of occurrence at NPL 

sites, toxicity, and potential for human exposure. 

Further information:

• ATSDR ToxProfiles 2004TM CD-ROM - The toxicological profiles are also available as 

a complete set on CD-ROM. 

• Public Health Statements (PHS) - The PHS are a series of summaries about hazardous 

substances taken from Chapter One of their respective ATSDR Toxicological Profiles. 

• ATSDR ToxFAQsTM - The ToxFAQsTM are a series of 2-page fact sheets about 

hazardous substances. 

To request a copy of the ToxProfilesTM CD-ROM, PHS, or ToxFAQsTM call 404-498-0261 

or email your request to atsdric@cdc.gov. 

For more information on the above listed publications, write 

Division of Toxicology, Agency for Toxic Substances and Disease Registry 

1600 Clifton Road, Mailstop F-32, Atlanta, GA 30333 

For more information 24 hours/day

You may call the ATSDR toll free number at 1-888-42-ATSDR (1-888-422-8737) to get 24-hour 

recorded information about Division of Toxicology programs. This phone number includes 

options to be transferred to ATSDR personnel for technical assistance. 

ATSDR Internet home page via World Wide Web: http://www.atsdr.cdc.gov 

The profiles, public health statements, ToxFAQsTM and other information are available on the 

Internet. 
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Appendix G 

Acronyms and Abbreviations 

AKART All Known and Reasonable Technology 

BMP Best Management Practice 

CAO Critical Areas Ordinance 

CAFO Contained Animal Feeding Operation 

CCD Columbia Conservation District 

CD Conservation District 

CIDMP Comprehensive Irrigation District Management 

Plan 

CRB Columbia River Basalts 

CREP Conservation Reserve Enhancement Program 

CRP Conservation Reserve Program 

CTUIR Confederated Tribes of the Umatilla Indian 

Tribes 

CWA Clean Water Act (Federal) 

DEQ/ODEQ Oregon Department of Environmental Quality 

DOE/Ecology Washington State Department of Ecology 

DOH Washington State Department of Health 

DDD Dichlorodiphenyl Dichloroethane 

DDE Dichlorodiphenyl Dichloroethylene 

DDT Dichlorodiphenyl Trichloroethylene 

EES Economic and Engineering Services, Inc. 

EPA U.S. Environmental Protection Agency 

EQIP Environmental Quality Incentives Program 

ESA Endangered Species Act (Federal) 

GPS Global Positioning System 

HCP Habitat Conservation Plan 

MOA Memorandum of Agreement 

NOAA National Oceanic and Atmospheric 

Administration 

NPDES National Pollutant Discharge Elimination 

System 

NRCS Natural Resource Conservation Service 

NTR National Toxics Rule 

NTU Nephelometric Turbidity Unit 

ODFW Oregon Department of Fish and Wildlife 

OFM Washington State Office of Financial 

Management 

PCB Polychlorinated Biphenyl 

PNW Pacific Northwest 

RCW Revised Code of Washington 

RM River Mile 
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SPMD Semipermeable Membrane Device 

TMDL Total Maximum Daily Load 

TSS Total Suspended Solids 

USFS U.S. Forest Service 

USGS U.S. Geologic Survey 

WAC Washington Administrative Code 

WDFW Washington Department of Fish and Wildlife 

WRIA 32 Water Resource Inventory Area (Walla Walla 

Basin) 

WSU Washington State University 

WWCCD/WWCD Walla Walla County Conservation District 

WWTP Wastewater Treatment Plant 

mg/L milligrams per liter (parts per million) 

ug/L micrograms per liter (parts per billion) 

ng/L nanogram per liter (parts per trillion) 

ug/Kg micrograms per kilogram (parts per billion) 
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Appendix H 

Responsiveness Summary 

(Note: Due to editing, page numbers in the final draft of the submittal report may differ from 

those cited in the comments.) 
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1) Comment:

1.1) Response: 

Ecology agrees that maintaining and restoring riparian areas will be very important to the success 

of this TMDL. We are aware of and appreciate the work the local community has already 

accomplished with regard to water quality improvements. Ecology is committed to working 

cooperatively and collaboratively with the local community to implement sound watershed 

agricultural practices and partner with existing programs such as CRP and CREP to achieve the 

necessary water quality improvements. Ecology will continue to educate the local community 

about water quality issues and seek funding to help both educational and riparian restoration 

efforts. 
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2) Comment:
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-77

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2.1) Response: First Page, First Bullet

Flow information was used in the calculation of the allocations recommended in the Walla Walla 

toxics TMDL technical report. In addition to the data on general flow conditions (see technical 

report pages 45-46), flow data was also obtained from WWTP records (see technical report, page 

36, under Effluent Samples). Pages 101-102 of the technical report describe in detail how flow 

was used in the calculation of the loading capacities, load and wasteload allocations. We agree 

that the Walla Walla WWTP discharge to Mill Creek is relatively insignificant. The submittal 

report (p.27, 3rd paragraph, 3rd sentence) states “the WWTPs represent less than ten percent of 

the PCB load in the receiving waters and thus are not as important relative to nonpoint sources”. 

In addition p.32, final paragraph, 3rd sentence (same document) states “Nonpoint sources coming 

into the WWTPs may be contributing to elevate PCB levels found in the WWTP effluent.” 

However, effluent samples taken by Ecology of the WWTPs’ effluent did show PCB 

concentrations were in exceedance of state and federal water quality standards. Ecology is 

required under the federal Clean Water Act and RCW 90.48 to address water quality 

impairments to waters of the state. In the case of point source discharges such as WWTPs this is 

done in the form of wasteload allocations in a TMDL. RCW 90.48. requires that point source 

dischargers of pollutants into waters of the state use all known, available and reasonable methods 

of prevention, control, and treatment (AKART) to reduce pollutant concentrations to within 

acceptable limits, regardless of whether the facility in question is the source of the pollutant or 

merely the conduit. 

2.2) Response: First Page, Second Bullet

At the time the phrase referenced in the bullet was written, the Walla Walla WWTP was still in 

the process of developing a water re-use program. This phrase has now been removed from the 

text to reflect the latest developments. 

2.3) Response: Second Page, First Bullet

The toxics TMDL submittal report does not imply or state that Ecology’s intention is to restore 

Mill Creek to a ‘pristine’ state. The toxin reductions required in the report are those necessary to 

meet state and federal water quality standards, but will not completely eliminate these toxins. 

2.4) Response: Second Page, Second Bullet

See response to 2.1) First Page, First Bullet

2.5) Response: Second Page, Third Bullet

We agree that carp and suckers are not consumed by a large segment of the local population. 

However, the human health criteria and water quality targets in the TMDL are intended to make 

it safe to eat all fish species caught in the river. The technical study analyzed carp and suckers, in 

addition to pike minnow, carp, catfish, and smallmouth bass. These are the predominant resident 

fish species that presently exist in the river. Migratory species like steelhead were not analyzed 

because the results would primarily reflect residues accumulated elsewhere. The selection of 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-81

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water quality targets that will bring the river into compliance with pesticide and PCB standards 

was based on water quality criteria established by EPA, not on the levels of contamination in the 

Walla Walla fish and analyzed for the technical study. While there is some evidence that 

pesticide concentrations have decreased over time, the comparison shown by Mr. Slovensky to 

illustrate a decrease in PCB concentrations in suckers is not appropriate because the older data 

are for whole fish samples and the newer data are for fillet samples and are therefore not 

comparable. 

2.6) Response: Second Page, Fourth Bullet, First Point

From the information cited by Mr. Slovensky it does appear that the Montana human health 

criteria are based on a less protective risk factor than Ecology’s criteria. In the National Toxics 

Rule, EPA gave the states leeway to select either a 10-5 (one in one hundred thousand) or 10-6

(one in one million) risk level; Washington chose 10-6. 

2.7) Response: Third Page, First Point

See response to 2.5) Second Page, Third Bullet

2.8) Response: Third Page, Second Point

Ecology remains committed to encouraging the use of applicable BMPs and/or AKART to 

address all sources of PCBs in the Walla Walla Basin. Specific strategies for addressing various 

contaminant sources will be addressed in the Detailed Implementation Plan to be compiled in 

collaboration with the Walla Walla TMDL advisory group. As part of this process the advisory 

group may choose to investigate potential PCB contaminated paint in the baffle system and 

accompanying channels. However, known PCB point sources such as the effluent from the Walla 

Walla and College Place WWTPs are required under state and federal legislation to receive a 

wasteload allocation. 

2.9) Response: Third Page, First Bullet

See response to 2.1) First Page, First Bullet and 2.8) Third Page, Second Point. We agree that 

PCB congener analysis is expensive, but costs could be lowered if a simple data report is 

requested vs. an exhaustive data package. 

2.10) Response: Third Page, Second Bullet

See response to 2.1) First Page, First Bullet
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2.11) Response: Fourth Page, First Bullet

The chart plots data for creeks that have significant urban and/or agricultural land use, so would 

not be considered “background” in the sense of being uncontaminated. We agree that the levels 

in WWTP effluent appear to be generally similar to or slightly less than the other sites shown in 

this comparison. 

2.12) Response: Fourth Page, Second Bullet

As described in the Walla Walla toxics TMDL technical report, PCB-4 (a specific PCB 

compound not found in environment) was spiked into these samples prior to analysis and thus 

should not be used to compare PCB levels among waterbodies. 

2.13) Response: Fourth Page, Third Bullet

See response to 2.1) First Page, First Bullet and 2.8) Third Page, Second Point. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-83

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3) Comment:

3.1) Response: Second Paragraph

The chlorinated pesticides and PCBs and associated sediment reductions prescribed in the 

submittal report are those calculated as necessary to achieve compliance with state and federal 

water quality standards. Page 97 of the Walla Walla chlorinated pesticides and PCBs TMDL 

technical report summarizes the success that has been achieved in the suspended solids/DDT 

TMDL for the Yakima River. The TSS and turbidity targets in the Yakima TMDL were similar 

to those proposed for the Walla Walla River. Page 106 of the technical report also cites a 

sediment loading study by Economic and Engineering Services, Inc. that concludes it is feasible 

to reduce sediment loading in the Walla Walla basin by 85%. 

3.2) Response: Third Paragraph
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The statement referred to was only intended to help describe the general conditions in the basin. 

The sentence now reads ‘flow is sustained though June from snowmelt’. The Walla Walla toxics 

TMDL technical report reviews historical data on pesticide levels in deposits of streambed 

sediments collected in the Walla Walla River and tributary mouths (Table 3). The concentrations 

were low to non-detectable. A USGS study referenced in the technical report (Mapes, 1969) 

found that most of the eroded soil in the Walla Walla basin consists of fine silt and clay that is 

kept in suspension by turbulence and transported out of the system. 

3.3) Response: Fourth Paragraph

The Walla Walla TMDL toxics technical report acknowledges that the TSS target is 

overprotective for chlorinated pesticides in the Touchet but points out that the more stringent 

target remains pertinent for the Touchet in order to meet turbidity standards in the mainstem, as 

well as for protection of fish and wildlife (page 96). Dry Creek also had at least one exceedance 

each for DDT, PCBs, chlordane, and heptachlor epoxide and is a significant source of turbidity 

to the mainstem. Each of these pesticide/PCB exceedances represents a one month average 

concentration. There is currently no information to suggest a “higher allowed TSS” target would 

be appropriate for Dry Creek. 

3.4) Response: Fifth Paragraph, First Three Sentences

We agree that all sources of suspended solids do not have equal amounts of the compounds in 

question. However, as described in the technical report, it is clear that the Walla Walla and its 

tributaries have significant water quality problems that include chlorinated pesticides, PCBs, 

TSS, and turbidity to varying degrees depending on location. These streams must meet water 

quality standards for these parameters, and others not addressed in this report, in order for water 

quality to be improved. A range of beneficial uses are affected including sport fishing, fish and 

wildlife habitat, and aesthetic values (see pages 87-94 of the technical report). The technical 

study showed that once TSS levels in the mainstem are reduced below 50 mg/L one would 

expect the river to be in compliance with pesticide standards. This presumes a basin-wide 

approach to the problem, which is appropriate given the range of impaired uses and sources. 

3.5) Response: Fifth Paragraph, Final Sentences

The distinction here is that 100 mg/L TSS predicts DDE violations, while the TSS target of 50 

mg/L takes into account the total DDT concentration (i.e., DDT plus its breakdown products 

DDE and DDD). The 30 mg/L target is based solely on meeting turbidity standards. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-85

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4.) Comment:

4.1) Response: 

See responses to Comment 3 above. 
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5.) Comment:
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-87

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5.1) Response:
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5.2) Response: Following negotiations with the Walla Walla Watershed Planning Department, 

Ecology agreed to add language to the submittal report that covered the outstanding issues that 

the TMDL advisory group felt needed addressing. This language appears in its entirety (as 

shown below) in the submittal report on pages 42 and 45 (the page numbers referred to below 

have changed due to subsequent editing) with minor additions as approved by the Walla Walla 

Watershed Planning Department. Ecology’s additions are shown in bold.

Additional TMDL language for PCB/Chlorinated Pesticides Submittal Report

Page 39 – prior to table 

As stated in the Walla Walla Watershed Plan, no organization or person is required to take on a 

commitment without their consent. However, once an organization has formally agreed to 

implement actions identified in the plan, it is expected these commitments be honored; 

recognizing funding limitations. The watershed plan does not create any obligations for private 

businesses, citizens or landowners. However, there are actions identified for voluntary action in 

the private sector. Although the Watershed Planning and TMDL processes are 

fundamentally different, Ecology has and will continue to seek opportunities for 

collaboration and cooperation between the two processes. It should be noted that Ecology is 

required under the federal Clean Water Act to conduct TMDLs and ensure clean water. 

To be included on page 41– end of page 

The following items were identified by the Walla Walla TMDL advisory group which will 

be looked at during the development of the Detailed Implementation Plan (DIP): Several 

TMDL program implementation topics have emerged that warrant emphasis in the water quality 

strategy for the TMDL implementation plan. It is the desire of several members of the TMDL 

Advisory Committee that these site specific issues be discussed in more detail during the 

Detailed Implementation Plan (DIP) development. Further public input will be sought to help 

prepare this plan. The plan will identify how, when, and where voluntary restoration activities 

will be implemented. 

Actions recommended in the DIP are intended to be specific enough to clearly identify the 

actions and results; yet general enough to permit some flexibility in carrying them out. It is 

recognized that some actions will require further investigation prior to full implementation. 

Additionally it is recognized that some actions can be carried out only if funding is provided by 

the state legislature or other funding agencies, and that funding decisions will be made over a 

period of months or years following plan adoption. 

The following concepts will be looked at in further detail during the Detailed Implementation 

Plan development: addressing the correlation between TSS and Turbidity to toxins in the 

Touchet River basin and the Dry Creek basin; identifying historic background levels for turbidity 

in the Walla Walla watershed and various tributaries, including identification of additional 

sampling sites including soil testing and streambed sediment loads; identifying additional 

sampling methods; identification of geographic source differences for toxin contamination 

including possible atmospheric deposition. As long as TSS continues to be the surrogate 

measure of chlorinated pesticides periodic validation of the current formulas should be made. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-89

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Many local interests in the Walla Walla Basin are involved with TMDL planning and 

implementation. During the development of the DIP, in areas where soils contributing to 

turbidity are found to have high levels of pollutant present, special emphasis on helping to 

relieve the problem will be employed. Ecology will continue to work closely with these basin 

interests to address outstanding issues.
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6.) Comment:
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-91

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6.1) Response: p.9 Change made. 2nd Paragraph, 2nd sentence now reads – “...until the EPA 

approves the new standards” 2nd paragraph, final sentence now reads – “However, the toxics 

criteria for this TMDL are not being revised and are still in effect in the same form they will be 

in after the revised standards are approved”. 

6.2) Response: 3rd Paragraph – The final sentence of paragraph 2 already states that which was 

said in paragraph 3. Paragraph 3 was therefore redundant and deleted from the text. 

6.3) Response: 4th Paragraph – changes made 

6.4) Response: p.10, 1st paragraph – change made 

6.5) Response: p.11 – addition made 

6.6) Response: p.17 1st paragraph, 1st sentence - sentence now reads – “...the levels of 

chlorinated pesticides and sediment load in the water column. The correlation between PCBs and 

sediment loads was weaker”. 
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6.7) Response: Pg 26 final paragraph, last sentence - sentence added-“TSS reductions down to 

5mg/L are deemed necessary to achieve compliance with toxics criteria” 

6.8) Response: Pg.27-28 first two paragraphs - First sentence (page 29 second paragraph) now 

reads-“TSS targets of 50mg/L and 5mg/L in the mainstem Walla Walla and tributaries, and the 

East Little Walla Walla and Yellowhawk Creeks respectively are set to achieve....” p.30 first 

paragraph, and p.33 discuss why more stringent TSS targets were deemed necessary in the East 

Little Walla Walla and Yellowhawk Creeks. 

6.9) Response: Load allocation, 2nd paragraph – The use of the term ‘background’ in this 

paragraph refers to TSS background levels and not contaminant background levels. The central 

premise of this report is that soils are the chief vector for legacy chlorinated pesticides and PCBs 

entering the water column in the Walla Walla basin, hence its mention here. Although no natural 

‘background’ levels exist for chlorinated pesticides and PCBs (as these are manmade 

compounds), some degree of sediment loading can be expected hence the term ‘background’. 

The first sentence of this paragraph has been revised to better clarify that the word ‘background’ 

refers to TSS. 

6.10) Response: p. 29 1st paragraph – Toxaphene was added to list of contaminants in the final 

paragraph before the Load Allocation section. As the first paragraph on page 29 does not list any 

contaminants specifically, it is unclear what this comment is referring to. The Load Allocation

section (p. 28) of the report states that the Washington state water quality criteria are the ultimate 

basis for the sediment allocations and TSS targets. We believe the report explains clearly under 

the Technical Analysis and Loading Capacity sections how the criteria were employed in 

calculating these. In addition these methods are explained in further detail in the Walla Walla 

chlorinated pesticides and PCBs TMDL technical report. The applicable toxaphene criteria are 

listed in Table 1, of the submittal report. 

6.11) Response: Pg 31 3rd second full paragraph (now pg. 34 first paragraph) - sentence 

amended to-“...the Walla Walla River and its tributaries at the ....”. p.32, 1st paragraph, 3rd

sentence (now pg. 35 first paragraph) under the Wasteload Allocation section: sentence amended 

to-“...to the Walla Walla River and its tributaries are present...” 

6.12) Response: p.35 last bullet - bullet removed. 
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7.) Comment:
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-95

Submittal Report 

7.1) Response: Second Paragraph, First Sentence

There are at least four laboratories (see table below) in North America certified to analyze lowlevel PCB congeners by EPA Method 1668 (High Resolution GC/MS). 

LabName City ContactPhone EMailAddress 

Axys Analytical Services Ltd Sidney, BC (250) 655-5800 dfyles@axys.com 

Pace Analytical Services, Inc. Minneapolis, MN (612) 607-1700 cgaylord@pacelabs.com 

Pacific Rim Laboratories, Inc. Surrey, BC (604) 532-8711 dave@pacificrimlabs.com 

STL Sacramento West Sacramento, CA (916) 374-4308 lstafford@stl-inc.com 

EPA considers the analytical method to be accurate below 1 ppt. 
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7.2) Response: Second Paragraph, Second Sentence

The Walla Walla toxics submittal report, Page 10, final paragraph states: “Washington state 

water quality criteria that apply to 303 (d) listed pesticides and PCBs in the Walla Walla 

drainage...... were promulgated for Washington in the EPA National Toxics Rule (40 CFR 

131.36).” Supporting information on how EPA derived human health criteria for PCBs and other 

chemicals can be found at: http://www.epa.gov/waterscience/criteria/humanhealth/

7.3) Response: Second Paragraph, Third Sentence

Field procedures, analytical methods, and data quality relevant to PCBs are described on pages 

21- 43 of the Walla Walla toxics TMDL technical report. Details of the analytical methods used 

for PCBs can be found at http://www.epa.gov/sw-846/main.htm and 

http://synectics.net/resources/. 

7.4) Response: Third Paragraph, First and Second Sentence

See response to 7.2) Second Paragraph, Second Sentence above 

7.5) Response: Fourth Paragraph, Final Sentence

See response 7.2) Second Paragraph, Second Sentence above and also response to Mr. Putnam 

9.5) 5. The PCB human health criteria are based on the commercial mixtures of PCBs used in the 

laboratory studies that established animal carcinogenicity. 

7.6) Response: Page Two, Final Two Paragraphs

Ecology is mandated under the federal Clean Water Act and RCW 90.48 to address water quality 

impairments of waters of Washington state. Ecology’s sampling of the effluent from the Walla 

Walla and College Place WWTPs found PCB levels to exceed state and federal water quality 

standards, which resulted in these two facilities being assigned wasteload allocations. Under 

WAC 173-201A-510 these facilities have 10 years to achieve full compliance with PCB limits 

following adoption in their NPDES permits, during which time Ecology is committed to working 

cooperatively and collaboratively with the WWTPs to develop strategies to address these 

impairments. Ecology does not recommend any dredging as a remedial action for PCB clean-up 

in the Walla Walla River. 
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8.) Comment:
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8.1) Response: (1) The water quality criteria on which the plan is based apply to a range of fish 

species, not just carp or suckers. The same criteria and TMDL targets would apply regardless of 

the type of fish collected during the technical study. Also see response to Mr. Slovensky’s 

comments 2.5) Second Page, Third Bullet.

8.2) Response: (2) See response to Ms. McConville 7.1) Second Paragraph, First Sentence. 

There are at least four laboratories in North America certified to analyze PCB congeners. EPA 

considers the analytical method to be accurate below 1 ppt. We agree that it is expensive. Cost 

per sample is in the range of $600 - $800 for a water sample, but could be lower if a simple data 

report is requested vs. an exhaustive data package. 

8.3) Response: (3) The samples collected by Ecology of the effluent from the Walla Walla and 

College Place WWTPs showed that PCB concentrations exceeded Washington water quality 

standards and therefore these facilities were assigned wasteload allocations. Ecology is mandated 

under the Clean Water Act and RCW 90.48 to ensure water quality impairments are addressed. 

The Walla Walla penitentiary is currently regulated under a temporary state waste discharge 

permit. The permit contains no PCB limit at this time as no information currently exists to 

substantiate such action. However if it is determined that a PCB impairment exists appropriate 

limits may be added to the permit in future. RCW 90.48. requires that point source discharges of 

pollutants into waters of the state use AKART to reduce pollutant concentrations to within 

acceptable limits, regardless of whether the facility in question is the source of the pollutant or 

merely the conduit. PCBs are manmade highly persistent carcinogenic toxins. There are no 

‘background’ levels for these compounds as they do not occur naturally in the environment. 

8.4) Response: (4) The current NPDES permits for the College Place and Walla Walla WWTPs 

do not specifically contain any limits for PCBs, because the wasteload allocation assigned in the 

TMDL submittal report has not yet been approved by EPA. Once the draft of the TMDL 

submittal report has been finalized it will be sent to EPA for additional review and approval. 

Once EPA approves the final draft of the report the PCB wasteload allocations will be adopted 

into the current NPDES permits. It is expected that the cities of College Place and Walla Walla 

will adjust their pretreatment standards in accordance with the Walla Walla toxics TMDL and 

any permit changes. 

8.5) Response: (5) The chemical data in the technical report accounted for the method blank in 

keeping with requirements of the EPA methods used in the analyses. This is discussed in further 

detail in response to Dr. Esvelt’s comments 17.2) 3a, 3f , 3g and 4 below. 
Walla Walla River Chlorinated Pesticides and PCBs Total Maximum Daily Load Page H-99

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8.6) Response: (6) See response to Mr. Slovenky’s comment 2.2) First Page, Second Bullet. 

8.7) Response: (7) The technical report included an example calculation of loading capacity for 

pesticides and PCBs in the Walla Walla mainstem, using the harmonic mean flow for the period 

of record (page 101 of the chlorinated pesticides and PCBs toxic report). This is a typical 

approach for determining loading capacity in TMDLs. The report estimated loading capacities 

for TSS based on the 90th percentile flow. Loading capacities for PCBs were also calculated for 

Mill Creek and Garrison Creek, taking into account the time period when WWTP effluent is 

discharged to these creeks; the former used the harmonic mean for December through April, and 

the latter used the harmonic mean for the entire year. 

8.8) Response: (8) The wasteload allocation for the Walla Walla treatment plant was based on 

the harmonic mean for Mill Creek for December through April. 

 

8.9) Response: (9) See responses to Ms. McConville’s comments 7.5) Fourth Paragraph, Final 

sentence. Washington state’s chlorinated pesticide and PCB water quality criteria are 

promulgated by the EPA National Toxics Rule. The load and wasteload allocation assigned in 

this report were calculated as those necessary to achieve compliance with these criteria. 

8.10) Response: (10) and (11) The public comment period was extended an additional 30 days, 

and the relevant data was turned over to Dr. Esvelt as requested. See responses to Dr. Esvelt’s 

comments for further information. 
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9.) Comment:

9.1) Response: (1) The wasteload allocation for the College Place WWTP effluent is based on 

the human health water quality criterion for PCBs. This criterion is much lower than drinking 

water limits because fish bioaccumulate PCBs to levels tens of thousands of times higher than in 

the surrounding water. Also, drinking water limits take into account the economic impact of the 

regulation. 

9.2) Response: (2) See response to Ms. McConville 7.1) Second Paragraph, First Sentence.

There are at least four laboratories in North America certified to analyze PCB congeners. EPA 

considers the analytical method to be accurate below 1 ppt. Also see response to Mr. Slovensky’s 

comments 2.9) Third Page, First Bullet and response to Mr. Nicholson’s comment 8.2) #2. 

9.3) Response: (3) See response to Mr. Nicholson’s comment 8.2) #2.

9.4) Response: (4) The technical study analyzed carp and suckers, in addition to pike minnow, 

carp, catfish, and smallmouth bass. These are the predominant resident fish species that presently 

exist in the river. Migratory species like steelhead were not analyzed because the results would 

primarily reflect residues accumulated elsewhere. The selection of water quality targets that will 

bring the river into compliance with pesticide and PCB standards was based on water quality 

criteria established by EPA, and analyzed for the technical study. See also response to Mr. 

Nichloson’s comment 8.2) #1 and response to Mr. Slovensky’s comments 2.5) Second Page, 

Third Bullet.
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9.5) Response: (5) The EPA human health criteria at issue in the TMDL are based on total 

PCBs. The animal exposure data from which the criteria were derived were obtained using 

commercial Aroclor mixtures which contain congeners with a wide range of toxicities. EPA 

recommends summing congeners when assessing compliance with water quality criteria. See 

also responses to Ms. McConville’s comments 7.2) Second Paragraph, Second Sentence and 

7.5) Fourth Paragraph, Final Sentence. 

9.6) Response: (6) The chemical data in the technical report accounted for the method blank in 

keeping with requirements of the EPA methods used in the analyses. See also response to Mr. 

Nicholson 8.5) 5. 
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10.) Comment:

10.1) Response: (1) Many of the Best Management Practices (BMPs) that are recommended in 

the report have been employed by farming communities across the state including the Walla 

Walla drainage to good effect. Ecology acknowledges the positive conservation work 

accomplished by local entities through the implementation of BMPs, and encourages more of the 

same. 

10.2) Response: (2) The chlorinated pesticides (e.g. DDT) addressed in this report are legacy 

pollutants in the sense that they were banned during the 1960’s, 1970’s and 1980’s, and no 

longer see large scale agricultural use in the USA. However, these chemicals have a propensity 

to bond with soil particles, and breakdown very slowly. Current application is not considered a 

threat to water quality in the area, but the erosion of contaminated soils in areas where 

chlorinated pesticides were previously applied is indeed considered a problem. 
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10.3) Response: (3) Although we acknowledge that water quantity may have an effect on water 

quality impairments, flow issues are beyond the scope of this TMDL document. Ecology’s Water 

Resource Program and Shorelines and Environmental Assistance Program in collaboration with 

local community entities like Watershed Planning Units is/are responsible for managing water 

quantity related issues across the state. Every effort is made to facilitate cross-program 

communication and cooperation to ensure best management of the state’s water resources. 

10.4) Response: (4) Land use in the Walla Walla drainage is predominately agricultural, and as 

such point source pollution dischargers are not abundant. In this TMDL the only point-source 

polluters identified as contributors to the chlorinated pesticides and PCB problem in the Walla 

Walla are the wastewater treatment plants (WWTPs) for the cities of Walla Walla and College 

Place. Analysis of effluent samples collected from these facilities showed PCB concentrations 

were above state water quality criteria and therefore they were assigned wasteload allocations. 

See also response to Mr. Slovensky’s comment 2.2) First Page, Second Bullet. Stormwater 

runoff from urban environments such as the cities of Walla Walla and College Place was not 

sampled during Ecology’s study of the Walla Walla area, and it was not possible to assign 

allocations to this potential source. However, local authorities’ responsibilities under current 

federal and legislation and local ordinances are mentioned in the report and local authorities are 

encouraged and expected to abide by said regulations. 
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(Note – the first letter from the Confederated Tribes of the Umatilla Indian Reservation was 

received a few days prior to the start of the public comment period, but because we believe it 

provides important detail to the comments received later in the second letter, we decided to 

include the first letter):
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11.) Comment:
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11.1) Response: Sep 16th letter, First Page, Second Paragraph, and Nov18th letter, Final Two 

Paragraphs

Ecology greatly appreciates the efforts that the Confederated Tribes of the Umatilla Indian 

Reservation (CTUIR) staff have put into the chlorinated pesticides and PCBs TMDL project over 

the past few years, and believe that the interest, insight, and information provided by your tribe 

has been vital in developing a successful TMDL project. The targets in the TMDL are based on 

the water quality criteria in standards and federal rule (40CFR131.36), and are the water quality 

standards-based load allocations that would form the basis of a legal agreement with the USEPA. 

The goals in the TMDL are based on site-specific considerations (in this case the larger amounts 

of fish consumed by the Umatilla Tribe and the subsequent higher risk the tribe incurs) and are 

not part of the water quality standards-based load allocation agreed upon with the USEPA. 

Because our toxic criteria in our standards and the federal rules serve as the legal foundation for 

our Clean Water Act regulatory actions we cannot use a numeric criterion that is not in our 

standards. Ecology is committed to working with the other Pacific Northwest (PNW) states and 

the USEPA to reduce toxics in water and fish to levels protective of the different groups that use 

or could use these resources. This includes tribal consumers. The early planning stages of this 

effort are now focused on the Columbia River. In the specific case of the Umatilla tribe and the 

Walla Walla River, Ecology will begin the toxics reduction program by working with local 

groups and the tribe to develop and implement Best Management Practices (BMPs) or other 

control strategies to reach the reductions identified as targets in the TMDL. Once these targets 

are met, Ecology will continue to work toward meeting the more stringent TSS goals. However 

as these goals are not based on state water quality standards they can have no regulatory 

significance, hence the use of the word ‘goal’. Ecology’s intent in this TMDL program is to 

focus state resources on actions that will lead to reductions in toxics in the water and sediments, 

and subsequently to reductions in toxics in the fishery resources and other aquatic life in the river 

system. 
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11.2) Response: Sep 16th letter, Second Page, First Paragraph 

All of the pesticides in question have an affinity for soil particles. As stated in the chlorinated 

pesticides and PCBs TMDL technical report (page 86): “Since the other pesticides of concern are 

generally present at lower levels than DDE and exceed their criteria to a lesser degree, land use 

changes directed at meeting a DDE-based target would also effectively address these chemicals.” 

We cannot envision any other outcome than a reduction in pesticide levels in Walla Walla as 

TSS levels are brought under control. However, "site-specific evidence” for water quality 

improvements will require BMP implementation and effectiveness monitoring as described in 

the submittal report. 

11.3) Response: Sep 16th letter, Second Page, Second Paragraph

It is not clear what “biological pools” this comment refers to. Aquatic animals and plants would 

be expected to come into equilibrium with the DDT concentration in the ambient water and thus 

would not constitute a source in the usual sense of the word. We agree that small terrestrial 

inputs of DDT compounds may cause unacceptable levels in the receiving waters. While many 

examples exist of significant reductions in fish tissue concentrations following source control of 

DDT, only time will tell what level of cleanup can be achieved in the Walla Walla River. The 2nd

comment in this paragraph was addressed in Ecology’s reply to the preceding paragraph. We 

agree the relationship between TSS and DDE determined for the mainstem may not hold for 

other areas. The technical report does however include an analysis that suggests the TSS target 

for the mainstem would be effective in meeting human health criteria for DDT compounds in 

most tributaries (chlorinated pesticides and PCBs TMDL technical report, pages 84-85). A sitespecific TSS target was developed for two of the most contaminated tributaries, Yellowhawk 

Creek and the East Little Walla Walla River. At the request of the TMDL advisory group, 

additional language was added to submittal report on pages 42 and 45 that describes further 

efforts to address this issue. These will be dealt with during the development of the Detailed 

Implementation Plan in collaboration with the TMDL advisory group. 

11.4) Response: Sep 16th letter, Second Page, Third Paragraph, and Nov 18th letter, Final Two 

Paragraphs

As a result of subsequent negotiations with CTUIR staff, Ecology has added text to the Load and 

Wasteload Allocation section of the toxics submittal report (page ) that addresses this concern. 

The TSS targets represent Ecology’s adaptive management tool for assessing the success of 

BMP implementation and therefore will remain where they are in the text. 
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12.) Comment: 

12.1) Response:

We feel federal and state programs such as the Conservation Reserve Program (CRP), 

Conservation Reserve Enhanced Program (CREP), Environmental Quality Incentives Program 

(EQIP), and other existing conservation programs serve both the producer and environment 

equally well. We financially support conservation efforts through grant programs, such as the 

Centennial Clean Water Fund (CCWF) and Environmental Protection Agency (EPA) Section 

319 Funds. These grant programs are applied for and administered by local entities. We have 

committed to work with local agencies, communities and private landowners to attain clean 

water goals outlined in the TMDL. However, Ecology retains the right to pursue enforcement 

action under the Clean Water Act and RCW 90.48 when such action is deemed appropriate. 
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13.) Comment:
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13.1) Response: First Page, Second Paragraph, Second Sentence 

Ecology is mandated under the Clean Water Act and RCW 90.48 to address water quality 

impairments. Washington state standards are derived from the National Toxics Rule, and they 

represent levels deemed necessary to protect human health and aquatic life from the harmful 

effects of these known or suspected carcinogenic substances. TMDLs do not add any further 
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regulation than already exists under this legislation. TMDLs evaluate water quality and devise a 

plan to improve water quality that may result in changes to permit limits. TMDLs focus and 

coordinate programs and groups already working on water quality issues to restore the water 

body to a healthy condition. 

13.2) Response: First Page, Third Paragraph, Second to Fourth Sentences

TMDLs are not a regulatory policy. Please see response above. Semipermeable membrane 

devices (SPMDs) have been shown to give results that are comparable to other low-level 

sampling methods. Studies in support of this conclusion are: 

Ellis et al. 1995. Evaluation of Lipid-Containing Semipermeable Membrane Devices (SPMDs) 

for Monitoring Organochlorine Contaminants in the Upper Mississippi River. Environ. Toxicol. 

Chem. 14:1875-1884. 

Hyne, R. et al. 2004. Comparison of Time-Integrated Pesticide Concentrations Determined from 

Field-Deployed Passive Samplers with Daily River-Water Extractions. Environ. Toxicol. Chem. 

23(9): 2090-2098. 

Rantalainen et al. 1998. Lipid-Containing Semipermeable Membrane Devices (SPMDs) as 

Concentrators of Toxic Chemicals in the Lower Fraser River, British Columbia. Chemosphere 

37: 1119-1138. 

Other low-level sampling methods were not used in the Walla Walla because they require using 

complex extraction devices in the field and give a measurement that represents only a single 

point in time vs. the month long deployment period for SPMDs. The SPMD data collected for 

the TMDL were used in conjunction with conventional sampling of whole water grab samples, 

fish tissue, and WWTP effluent samples to identify and rank sources. SPMDs are particularly 

well suited to this task because they provide extremely low detection limits and give good 

reproducibility because of their standardized design. The water quality targets and load 

allocations in the TMDL were based on the conventional sampling data, with the exception that 

the SPMD data were used to establish the ratio between DDT and its breakdown products DDE 

and DDD. The SPMD extracts were analyzed by EPA methods. 

13.3) Response: First Page, Third Paragraph, Final Sentences

Binding is primarily a function of the organic carbon content of the particles. SPMDs measure 

the dissolved fraction which is available for uptake by plants and animals. This is one of the 

major advantages of their use over whole water samples. The EPA recommends using the 

dissolved rather than total water concentration to assess bioaccumulation of pesticides and PCBs 

in fish: 

EPA. 2000. Methodology for Deriving Ambient Water Quality Criteria for the Protection of 

Human Health. EAP/822/B-98/005. 

It is true that SPMD data cannot be directly compared to fish tissue data because 1) there is no 

metabolic breakdown or excretion, 2) the SPMD uptakes rates are faster and their capacity 

greater, and 3) SPMDs seldom reach steady state concentrations. However when published 

bioaccumulation data are used in conjunction with SPMD data to predict fish tissue 

concentrations, the predicted and measured concentrations usually agree. 
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13.4) Response: First Page, Fourth Paragraph

The coefficient of determination or R2 of 0.73 was for all mainstem data. The Walla Walla toxics 

technical report does state on page 84 that the R2 of all the combined data (0.45) alone would not 

be able to predict DDE violations Therefore a quantile plot was used to confirm that a DDEbased TSS target was accurate and reasonable (page 84-86) across the watershed. 

13.5) Response: Second Page, First Paragraph

The purpose of the Walla Walla TMDL submittal report is to give an overview of the chlorinated 

pesticides and PCBs problem in the Walla Walla Basin and recommend broad strategies to 

achieve compliance with state and federal water quality criteria. Ecology acknowledges that 

further monitoring and land use assessments are needed to find locations contributing to the 

problem. However, this level of detail is more appropriate in the Detailed Implementation Plan 

(DIP) to be developed later in collaboration with the Walla Walla TMDL advisory group. 

Language detailing the need for additional monitoring has been added to pages 42 and 45 at the 

request of the Walla Walla TMDL advisory group. 

13.6) Response: Second Page, Second Paragraph

The TSS load reductions allocated in this report are those Ecology has deemed necessary to 

achieve compliance with state and federal chlorinated pesticide and PCB water quality standards. 

The turbidity-based targets were calculated from all relevant data, following nationally 

recognized procedures, and are based on the 90th percentile of background turbidities recorded at 

the established background turbidity location. The 90th percentile is the turbidity exceeded by 

10% of the samples. This EPA-approved approach allows for seasonal variation and natural 

generation of suspended sediment and turbidity. Adaptive management is an integral part of 

TMDL implementation. In the event that management strategies outline in the submittal report 

are not successful, alternative approaches will be developed in conjunction with the TMDL 

advisory group and implemented. 

13.7) Response: Second Page, Third Paragraph, First Sentence

As noted on page 26 of the Walla Walla toxics technical report, the National Academy of 

Sciences has recommended the approach of using the relationship between a water quality 

indicator (pesticides in this case) and one or more predictor variables (TSS and turbidity in this 

case) as a ”simple and useful model for developing TMDLs”. The TSS and turbidity targets were 

developed as tools to be used in monitoring progress toward achieving water quality standards. 

As described in the technical report (page 83), “Setting water quality targets based on TSS and 

turbidity has the advantage of translating more directly to land use practices and being easier and 

less expensive to monitor than trace chemical concentrations. Additionally, TSS and turbidity 

levels in river and streams have a direct and quantifiable effect on the health of fish and other 

aquatic organisms, as well as aesthetic values.” The ultimate objective of this TMDL is to meet 

state pesticide/PCB criteria and turbidity standards. The technical study determined that the 

turbidity targets are necessary in order to achieve state water quality criteria in Washington 

Administrative code 173-201A. The TSS goals are necessary to protect people who consume 

large amounts of fish. 
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13.8) Response: Second Page, Third Paragraph, Remaining Sentences

Washington state water quality standards define background as “the biological, chemical, and 

physical conditions of a waterbody, outside the area of influence of the discharge under 

consideration.” Background for the Walla Walla River was established during the technical study 

at the state line to reflect minimal human influences on water quality. The turbidity targets are 

based on samples taken from this location. TMDL targets are the amount of pollution that needs 

to be reduced to meet existing state standards. 

14.) Comment:

14.1) Response:

Please see previous responses to 13. Mr. Greg Farrens, Mr. Robert Hutchens, Mr. Jack Myrick, 

and Dr. Roland Schirman. Several efforts were made to obtain representative data. Sampling for 

the TMDL technical study occurred from May 2002 until September 2003. During this time, 

fish tissue samples were collected, grab samples from the river and tributaries were taken, 

samples from the treatment plants were taken, and devices put into the water collected data for 

30 days. In addition, any available historic data was sought. Monitoring will continue to be an 

important part of the efforts to reduce chlorinated pesticides in the watershed. 
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The majority of the implementation activities or best management practices (BMPs) 

recommended in the report were taken from the Walla Walla Watershed Plan. These BMPs have 

already been applied by farming communities across the state including the Walla Walla 

drainage to good effect. The Submittal Report acknowledges watershed residents’ efforts to 

improve water quality through the implementation of BMPs and encourages more of the same. 

There are no natural sources of chlorinated pesticides or PCBs, but these man-made compounds 

do bind to soil particles. The turbidity targets in the TMDL are necessary to meet current state 

water quality standards and do not result in new regulations. The submittal report assigned TSS 

load allocations to 10 tributaries in addition to two for the upper and lower Walla Walla 

mainstem. Data collected during Ecology’s 2002-2003 study suggests that the pesticide problem 

is not isolated, but extends to varying degrees across the Walla Walla Basin (with the exception 

of the Touchet River drainage where the chemicals in question were not widely used 

historically). Refinement of the TSS targets may occur as a result of further monitoring during 

implementation. 

Financial assistance is needed to help watershed residents improve water quality. Some funding 

sources the agricultural industry may use to apply BMPs are mentioned on page 51 of the 

Submittal Report. Since TMDLs are neither a general permit nor a rule, economic impact 

statements are not a requirement. Economic impact statements, cost-benefit analyses, or 

economic analyses mandated by the Regulatory Fairness Act [Revised Code of Washington 

(RCW) 19.85] and Administrative Procedure Act (RCW 34.05) apply only to rules. In addition, 

the TMDL does not propose a specific course of action for a specific location. 
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15.) Comment:

15.1) Response: Second Paragraph

The time frame for technical studies conducted by Ecology is typically one year. Because a large 

number of samples were analyzed and the range of flows that occurred during the study included 

the normal range of flows, Ecology considers the study to be credible. 
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15.2) Response: Third Paragraph

The correlation between turbidity and toxics was demonstrated in the technical study suggests 

that reducing turbidity levels will decrease toxic concentrations. Ecology acknowledges that 

further monitoring and land use assessments are needed to find areas contributing to the problem. 

Language detailing the need for additional monitoring has been added to pages 42 and 45 at the 

request of the Walla Walla TMDL advisory group. Many of the strategies to reduce chlorinated 

pesticides and PCBs would also reduce turbidity levels. The TSS targets represent the minimum 

reductions necessary to meet state standards. 

15.3) Response: Fourth Paragraph

Financial assistance is needed to help watershed residents improve water quality. Some funding 

sources the agricultural industry may use to apply BMPs are mentioned on page 51 of the 

Submittal Report. Since TMDLs are neither a general permit nor a rule, economic impact 

statements are not a requirement. Economic impact statements, cost-benefit analyses, or 

economic analyses mandated by the Regulatory Fairness Act [Revised Code of Washington 

(RCW) 19.85] and Administrative Procedure Act (RCW 34.05) apply only to rules. In addition, 

the TMDL does not propose a specific course of action for a specific location. 

15.4) Response: Fifth Paragraph

Thank you for supporting the implementation strategy 
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16.) Comment:
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16.1) Response: Pg 4: Change made 

16.2) Response: Pg 5: Change made 

16.3) Response: Pg 6, First Comment: Change made 

16.4) Response: Pg 6, Second Comment: Addition made 
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16.5) Response: Pg 8, First Comment: The sample size in Ecology’s 2002-2003 water quality 

study met Washington Department of Health requirements. In addition the study methods, 

analysis and conclusions were subjected to extensive internal peer review and EPA review and 

found sound. 

16.6) Response: Pg 8, Second Comment: Changed to ‘the chief means’. The technical report 

found that the legacy chemicals addressed in this TMDL have bound with soil particles and are 

entering surface waters primarily through soil erosion from adjacent lands (where the chemicals 

were historically applied). The positive correlation between suspended sediments and toxic 

chemeicals is the foundqation for this conclusion. While other measures can and ought to be 

taken, reducing the amount of soil entering surface waters is certainly the most important step to 

take. 

16.7) Response: Pg 8, Third Comment: Addition made 

16.8) Response: Pg 17, First Comment: Addition made 

16.9) Response: Pg 17, Second Comment: See response to Dr. Schirman’s comments 3.2) Third 

Paragraph. Change made to the text for clarification.

16.10) Response: Pg 22: See response to Pg 8, Second Comment. 

16.11) Response: Pg 35: See response to Dr. Schirman’s comments 3.2) Third Paragraph.

16.12) Response: Pg 36, First Comment: See response to 16.6) Pg 8, Second Comment and 

16.9) Pg 17, Second Comment above. Background turbidity was assessed following standard 

Ecology procedure. Also see response to Mr. Farrens, Mr. Hutchens, Mr.Myrick, and Dr. 

Schirman, 13.7) and 13.8) Second Page, Third Paragraph. Sufficient turbidity and suspended 

sediment data were obtained to obtain the conclusions in the submittal report. No significant 

stream bottom sediment sinks were identified during Ecology’s 2002-2003 study with the 

exception of the Columbia River backwater in the lower Walla Walla River mainstem. This area 

is addressed on page 50, first bullet of the submittal report. 

16.13) Response: Pg 36, Second Comment: The data collected for this TMDL study show that 

there is a statistically significant positive relationship between Total Suspended Sediments (TSS) 

and chlorinated pesticides. Those areas such as the Touchet River drainage which did not see 

historically high levels of pesticide application would not be expected to see high levels of 

chlorinated pesticides in the water column. However, even those waterbodies that do not show 

exceedances for chlorinated pesticides may still require TSS reductions to meet water quality 

criteria for turbidity – as is the case for the Touchet River. 

16.14) Response: Pg 37, First Comment: The paragraph in question defines the summary 

implementation strategy and is standard language used in all TMDLs. A description of the 

implementation strategy to be used follows this paragraph. Ecology acknowledges and is 

appreciative of the voluntary implementation of water quality remedial projects that have already 

taken place in the Walla Walla River drainage. The data collected in this study indicates that 

much work remains to be done to achieve compliance with state water quality standards. 

Ecology will continue to seek collaborative and cooperative solutions to water quality 

impairments in the drainage by offering technical and financial assistance. However, under RCW 

90.48 and the federal Clean Water Act Ecology is responsible for ensuring clean water and 

retains the right to pursue enforcement actions where appropriate. 
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16.15) Response: Pg 37, Second Comment: Addition made 

16.16) Response: Pg 38, First Comment: Change made 

16.17) Response: Pg 38, Second Comment: See response to Pg 8, Second Comment above. 

16.18) Response: Pg 39: Change made 

16.19) Response: Pg 41, First Comment: Most private and public forestry lands in the Walla 

Walla drainage are situated in Oregon, hence Oregon can reasonably be expected to see more 

forestry related activities. In addition, forestry activities are restricted in the Mill Creek 

headwaters since it is a designated municipal watershed. The text of the report has been clarified. 

16.20) Response: Pg 41, Second Comment: Addition made 

16.21) Response: Pg 41, Third Comment: Change made 

16.22) Response: Pg 43: TMDLs are required for water bodies included on the 303(d) list and 

therefore are not voluntary. Targets are required parts of submittal reports and represent the 

amount that pollutants must be reduced in order to meet water quality standards. As such targets 

are not voluntary. See also response under 16.14) Pg 37, First Comment above. 

16.23) Response: Pg 45: Change made 

16.24) Response: Pg 49, First Comment: Change made 

16.25) Response: Pg 49, Second Comment: These areas have been identified as potential 

sample sites for evaluating whether or not the TMDL targets are being met. In order to determine 

if the TMDL targets are being met, monitoring should be conducted at sites comparable to those 

used in the technical study. The suggested sampling sites in question would represent 

comparable sampling locations. However, there is no obligation on Ecology or the TMDL 

advisory group to use these sample sites should they decide otherwise later. Also this does not 

preclude the inclusion of additional sample sites should it be deemed necessary. 

16.26) Response: Pg 50, First Comment: Change made 

16.27) Response: Pg 50, Second Comment: Addition made 

16.28) Response: Pg 51, First Comment: Addition made 

16.29) Response: Pg 51, Second Comment: The scope and purpose of future monitoring 

projects has yet to be determined, so it is not possible to say at this stage where the additional 

sampling sites will be located. This is something that will have to be determined when planning 

individual studies. See also 16.25) response to Pg 49, Second Comment above. 

16.30) Response: None of the chemical compounds that are addressed in this TMDL occur 

naturally in the environment, and as such no natural background exists for them. All the 

chemicals addressed in this report are known or presumed carcinogens, persistent in the 

environment, and bioaccumulate in animal tissue and therefore represent serious threats to 

human and aquatic life. In order to reflect the amount of turbidity that occurs naturally, human 

influences must be minimal to none existent. In this study, background was set at state line to 

include only that turbidity that is the result of processes within the study area. This background 

turbidity level was included in the calculation of TSS targets. Because background levels of 
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turbidity were assessed during the study and factored into the targets, naturally occurring levels 

of turbidity are not included in the margin of safety discussion. 

16.31) Response: Turbidity background levels were determined using an approved procedure, 

in accordance with state legislation that has been used in similar TMDLs. The methods applied 

in this TMDL have been subjected to internal peer review and EPA review and found sound. 

Also see Ecology’s responses to the Columbia Blue Mountain Farm Bureau’s comment 15.2) 

Third Paragraph and response to Mr. Farrens, Mr. Hutchens, Mr. Myrick, and Dr. Schirman 

comment 13.6), 13.7) and 13.8) Second Page, Second Paragraph and Third Paragraph.

16.32) Response: All 303(d) listings on the Washington side of the watershed are addressed in 

this TMDL. Each major tributary has been given a load allocation to achieve, so implementation 

activities can be customized based on the sources of chlorinated pesticides and/or PCBs found in 

each tributary. The report recommends that priority areas for remedial work be identified during 

the development of the Detailed Implementation Plan (DIP). 

16.33) Response: This report has referenced and drawn extensively from the WRIA 32 

Planning Unit Plan. Ecology is committed to continuing to work cooperatively and 

collaboratively with the Watershed Planning group as far as possible to achieve compliance with 

the water quality criteria. 
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17.) Comment:
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17.1) Response - 2: The WWTP wasteload allocations for PCBs were based on treatment plant 

flow and the human health water quality criterion. It is true that different methods were used to 

sample and analyze the receiving waters. The wasteload allocations for the WWTPs were 

determined by comparing PCB levels detected in the effluent with state water quality criteria. 

The receiving water PCB data were used only to put the WWTP PCB contribution in perspective 

and were not used in the calculation of the WWTP wasteload allocations. Furthermore, the 
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WWTP and receiving water PCB loads differed by an order of magnitude or more. Therefore the 

fact that different methods were used in their measurement does not seem to be a significant 

concern. 

17.2) Response 3a, 3f, 3g, 4: The calculation procedures for total PCBs are detailed in EPA 

Method 1668A. The complete text of the method can be found at http://synectics.net/resources/ 

and http://www.epa.gov/sw-846/main.htm. Environmental chemical data are normally not blank 

corrected therefore the Department of Ecology does not blank correct. With regard to the 5x rule: 

the general concept is that if the concentration in a sample is greater than 5 times the method 

blank, then it is assumed that most of the chemical is native to the sample, no more than 20% 

being due to blank contamination. In that instance the data are reported without blank 

correcting. If the method blank is higher, then the reporting limit must be raised. PCB congener 

data are usually not blank corrected. Blank correcting can be done, but only if large numbers of 

blanks are analyzed in conjunction with each sample set. Section 17.6.1.4.4 of EPA Method 

1668A for analyzing PCB congeners states that: “Blank-corrected results may be reported in 

addition to reporting of separate results for samples (Section 17.6.1.4.1) and blanks (Section 

17.6.1.4.2). The recommended procedure for blank correction (Reference 20) is that a result is 

significantly above the blank level, and the level in the blank may be subtracted, if the result is 

greater than the mean plus 2 standard deviations of results of analyses of 10 or more blanks for a 

sample medium.” The analyses conducted for the Walla Walla WWTPs followed the usual 

procedure of having a single method blank with each set of samples. Therefore the procedures to 

blank correct and calculate total PCB concentrations for the WWTP effluent samples are not 

appropriate in this case. 

17.3) Response 3b: The conclusion about low accuracy appears to stem from inappropriately 

blank correcting the data. Total PCB concentrations during this sampling event were in 

reasonable agreement. Two side-by-side samples were prepared over a two-day period by 

compositing subsamples of the effluent; one of the samples was split. The split results were 0.79 

and 0.74 ng/L, for an average of 0.76 ng/L. The other sample had 1.0 ng/L. The result used in the 

technical report was the average of the latter two values, 0.88 ng/L. Considering these 

measurements were being made at the sub-parts per trillion level and that the TMDL technical 

study extended over a one-year period, consistent results were obtained for both WWTPs. Total 

PCBs ranged from 0.75 – 0.88 ng/L in the Walla Walla effluent and 0.53 – 2.5 ng/L in the 

College Place effluent. College Place was experiencing an upset for part of the study and this 

may have contributed to the wider variation. Also see responses to 17.2) 3a, 3f, 3g,4. 

17.4) Response 3c: Unclear what error is being referred to here, unless it stems from blank 

correcting the data. The laboratory reported a total PCB concentration of 1290 pg/L. The TMDL 

technical report shows a value of 1.3 ng/L (1,290/1,000 = 1.290 ng/L rounded to 1.3 ng/L). 

17.5) Response 3d: The Walla Walla total PCB concentrations shown in the technical report - 

0.88 ng/L (May 02), 0.65 ng/L (Sept. 05) 0.75 ng/L (Dec. 05) 0.87 ng/L (Feb. 05) - do not appear 

to decrease significantly. 
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17.6) Response 3e: The College Place total PCB concentrations shown in the technical report 

were 2.5 ng/L (May 02), 0.92 ng/L (Sept. 05) 1.3 ng/L (Dec. 05) 0.53 ng/L (Feb. 05). College 

Place experienced some upsets during 2002 which may have caused this variation. 

17.7) Response 5: See responses to Mr. Slovensky’s comments 2.1) First Page, First Bullet.

17.8) Response 6., 6a, 6b, 6c, 6d, 7, 7a, 7b: See responses to 3a above and Ms McConville’s 

comments 7.5) Fourth Paragraph, Final sentence, and Mr. Nicholsn’s comment 8.9) #9 .

Washington state’s chlorinated pesticide and PCB water quality criteria are promulgated by the 

EPA National Toxics Rule. The load and wasteload allocation assigned in this report were 

calculated as those necessary to achieve compliance with these criteria. 

17.9) Response 8: We agree it would be inaccurate to assess the potential impact of Walla 

Walla WWTP by comparison to the loading capacity of the mainstem, which was calculated in 

the technical report using the harmonic mean for the period of record. However, as described on 

page 102, the loading capacity for PCBs in Mill Creek and assessment of the relative impact of 

Walla Walla WWTP was based on the harmonic mean flow in Mill Creek for December through 

April. 

17.10) Response 9: See responses to Mr. Slovensky’s comments 2.9) and 2.10) Third Page, 

First and Second Bullet; Ms McConville’s comments 7.1) Second Paragraph, First Sentence and 

7.6) Second Page, Final Two Paragraphs, Mr. Nicholson’s comment 8.2) #2, and Mr. Putnam’s 

comment 9.2) #2. 

17.11) Response 10: See responses to Mr. Slovensky’s comment 2.1) First Page, First Bullet, 

and 2.7) Third Page, Second Point, and Mr. Nicholson’s comment 8.3) #3. 

17.12) Response: Summary, Fourth Bullet: The Walla Walla WWTP will most likely have 

pretreatment authority in 2007, making assessment of the wastewater collection system the 

responsibility of the WWTP. We agree that an assessment of the collection system would be 

good initial step in addressing the PCB problem. 
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18.) Comment:
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18.1) Response: Second Paragraph -See response to Columbia Blue Mountain Farm Bureau’s 

comments 15.1) Second Paragraph. Data Ecology collected during the 2002-2003 sampling 

period show there is a significant chlorinated pesticides and PCBs water quality problem that 

needs to be addressed. Data suggest that the problem is too large to be an anomaly. 

18.2) Response: Third Paragraph - See previous responses to 1.1) Mr. Fishella’s comments, 

Dr. Schirman’s comments, 3.1) Second Paragraph and 3.4) Fifth Paragraph, 10.1) Louis Riley 

and Janice Riley’s comments #1, 12.1) Mr. Bishop’s comments, Mr. Farrens, Mr. Hutchens, Mr. 

Myrick, and Dr.Schirman’s comments 13.1) First Page, Second Paragraph, Second Sentence, 

13.6) Second Page, Second Paragraph, 13.7) Second Page, Third Paragraph, 14.1) Keith 

Farrens comments, and Columbia Blue Mountain Farm Bureau’s comments 15.1) Second 

Paragraph. 

18.3) Response: Fourth Paragraph - Fish tissue samples have been analyzed on three separate 

occasions over a recent 10-year period - 1992, 1993, and 2002 - and all of these investigations 

found impaired levels of chlorinated pesticides and PCBs. 
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19.) Comment: (Note: The following comments were received shortly after the close of the 

public comment period, but because we feel they elucidate Mr. Hutchens’ previous comments 

and raise some additional important points, we include them here.) 

19.1) Response: (1) No. Turbidity can be elevated without a violation of PCB or CP standards, 

if none of the constituents causing the turbidity contain PCBs or CPs. 

19.2) Response: (2) The TMDL did not set a standard for turbidity; that standard already exists. 

The turbidity standard has been part of the state’s surface water quality standards for decades and 

can be found at WAC 173-201A-030(1) and (2) [for Class AA and Class A waters]. The state’s 

turbidity standard is not an absolute value, but sets a maximum allowable change in turbidity 

based on an estimate of background turbidity levels. This was the basis for setting the TSS 

targets for turbidity compliance in the Walla Walla TMDL. The TMDL also recommends TSS 

targets that can be used as surrogates to track changes in chlorinated pesticide levels. 

19.3) Response: (3) See answer to Keith Farrens, 14.1) Walla Walla County Farm Bureau 

regarding random vs. timed sampling. 
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19.4) Response: (4) The PCB/Chlorinated Pesticide study was designed to collect the necessary 

information needed to develop a TMDL, but still stay within a reasonable budget. The costs of 

laboratory analyses for PCBs and chlorinated pesticides are much higher than for fecal coliform. 

It would have been prohibitively expensive to conduct fecal coliform like sampling for the toxics 

TMDL. The focus of the toxics TMDL was on the Walla Walla mainstem because that was the 

waterbody on the 303(d) list. The Touchet was not on the 303(d) list for pesticides or PCBs. 

19.5) Response: (5) The large volume of water that the Touchet River contributes to the Walla 

Walla mainstem has a cumulative dilution effect on the mainstem. However, data collect on the 

Touchet River indicates that the river is impaired for turbidity. All streams must meet water 

quality standards to protect beneficial uses, therefore the Touchet River still needs to meet TSS 

targets for turbidity compliance. 

19.6) Response: (6) Yes. One monitoring station at the mouth of the Touchet River is sufficient 

to make a determination as to whether the Touchet is a source of chlorinated pesticides, PCBs, 

TSS, and turbidity to the Walla Walla River. One site is not sufficient to determine what parts of 

the Touchet watershed are contributing to the problem. 

19.7) Response: (7) More restrictive targets were recommended for the East Little Walla Walla 

River and Yellowhawk Creek because pesticide levels were clearly much higher than in other 

tributaries. The technical report acknowledges that the basin-wide TSS/turbidity targets are 

overprotective for pesticides in the Touchet, but maintains that it is appropriate to apply them 

here because of the Touchet’s role in turbidity exceedances in the mainstem and for protection of 

fish and wildlife habitat (page 96). These streams need to meet water quality standards for 

turbidity as well as for PCBs and chlorinated pesticides. 

19.8) (8) Both watersheds showed a relationship between TSS, turbidity, and pesticides. The 

correlation exists irrespective of farming methods. The type of agriculture being practiced 

factors into remedies for the problem. 

19.9) (9) Since TMDLs must be approved by a federal agency, they do not meet the definition of 

action under SEPA [Washington Administartive Code (WAC) 197.11.704(2)(b)(3)]; therefore 

there is no responsibility to complete an environmental impact statement. TMDLs are also not 

considered to be a major federal action requiring NEPA analysis, as defined by EPA’s 

implementing regulation for the NEPA program at 40 CFR Part 6; therefore NEPA analyses are 

no completed for TMDLs. However, individual projects constructed to implement the TMDL 

may require SEPA/NEPA review. In other words, an environmental impact statement is not 

required since a specific course of action has not been proposed for a specific location. 

19.10) (10) It is true that the Walla Walla Watershed Planning Unit and various other entities 

focused on flow related issues have received more financial assistance than the TMDL advisory 

group and other entities working on water quality issues to date. Water quantity has often 

received more attention than quality across Eastern Washington due to the relatively arid 

conditions experienced there and the need to meet growing agricultural and urban needs. 

However, it should be also noted that the Walla Walla Watershed Planning Unit has been in 

existence far longer than the TMDL advisory group, and is further along towards project 

implementation than the TMDL process is. It is hoped that as the TMDL process moves closer 

towards project implementation there will be a rise in the number of water quality specific 

projects funded. Recently the Walla Walla Water Management Initiative began with the aim to 
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foster more cooperative and collaborative water management in the area, and water quality 

concerns will play an important role in this process. 

19.11) Response: (11) The Watershed Planning process is mandated by Washington state law, 

as a means to achieve locally driven management of water resources. Water quantity is the focus 

of such groups although water quality concerns are sometimes considered (See response to 

comment 19.10) # 10 above). Ecology is delegated authority to manage the federally mandated 

TMDL process. As such Ecology is required to ensure that water quality impairments are 

addressed and is responsible for achieving compliance with state and federal water quality 

criteria. Therefore, unlike in the Watershed planning process, Ecology retains control and 

decision making authority for setting TMDLs. However, Ecology recognizes that local 

knowledge and support of the process are essential for success and strives to get public 

involvement and input through entities like the TMDL advisory groups. Ecology is committed to 

working cooperatively and collaboratively with local communities and other entities to achieve 

water quality improvements. 
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Appendix I 

Public Participation Materials 
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