NONPOINT SOURCE ASSESSMENT REPORT

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HOH RIVER WATERSHED

JEFFERSON COUNTY, WASHINGTON WRIA 20

Submitted to:

U.S. ENVIRONMENTAL PROTECTION AGENCY

REGION 10 TRIBAL ASSISTANCE PROGRAM

1200 Sixth Avenue, Suite 155

Seattle, Washington 98101

Submitted by:

July 2026

Hoh Indian Tribe Natural Resources Department

2269 Lower Hoh Rd, Forks, Washington 98331

In cooperation with: WESTECH CONSULTING, LLC

937 Boathaven Drive, Port Angeles, Washington 98363

Trevor Shea, CEO

CONTENTS

OVERVIEW ................................................................................................................................. 34

INTRODUCTION ........................................................................................................................ 45

METHODOLOGY ....................................................................................................................... 67

Water Quality Monitoring Data ................................................................................................ 78

Equipment ............................................................................................................................... 910

Quality Assurance/Quality Control Protocols ........................................................................1011

Geospatial Data Sources ....................................................................................................... 1415

Historical Documentation ..................................................................................................... 1516

Limitations & Assumptions .................................................................................................. 1617

LAND USE SUMMARY ......................................................................................................... 1617

Forest Lands .......................................................................................................................... 1617

Developed Lands .................................................................................................................. 1920

Residential............................................................................................................................. 1920

Commercial ........................................................................................................................... 1920

Transportation ....................................................................................................................... 2021

Agricultural and Open Lands ................................................................................................ 2223

Other Land Cover Categories ............................................................................................... 2223

SURFACE AND GROUND WATER QUALITY .................................................................... 2829

Hoh Indian Reservation ........................................................................................................ 2829

Historical Monitoring Program ............................................................................................. 2830

Wetlands and Aquatic Features ............................................................................................. 3637

Ground Water Standards ....................................................................................................... 3637

Pollutants............................................................................................................................... 3738

RESULTS ................................................................................................................................. 3738

Nonpoint Source Assessment ................................................................................................ 4445

Data Gaps in Historical Record ............................................................................................ 4748

Results Assessment ............................................................................................................... 4748

DISCUSSION ........................................................................................................................... 4849

Temperature Impairments ..................................................................................................... 4849

Dissolved Oxygen Patterns ................................................................................................... 4951

pH Depression ....................................................................................................................... 5052

Sediment Sources .................................................................................................................. 5152

SELECTION OF BMPS ........................................................................................................... 5556

Selection Process .................................................................................................................. 5556

NPS CONTROL PROGRAMS ................................................................................................ 5860

EPA Programs ....................................................................................................................... 5860

Bureau of Indian Affairs Programs ....................................................................................... 5860

USDA Natural Resources Conservation Service Programs .................................................. 5860

NOAA Fisheries Restoration Programs ................................................................................ 5961

U.S. Fish and Wildlife Service Programs ............................................................................. 5961

Washington Department of Ecology Programs ..................................................................... 6062

Washington State Salmon Recovery Funding ....................................................................... 6062

Jefferson County Conservation District ................................................................................ 6062

North Paciﬁc Coast Lead Entity ........................................................................................... 6163

Olympic Peninsula Conservation Organizations .................................................................. 6264

Regional Foundations and Funding Organizations ............................................................... 6365

Academic and Research Partnerships ................................................................................... 6365

Volunteer and Community Organizations ............................................................................. 6466

Coordination Mechanisms .................................................................................................... 6466

CONCLUSION ......................................................................................................................... 6567

Meeting EPA Section 319 Requirements .............................................................................. 6567

REFERENCES ......................................................................................................................... 6769

APPENDICES .......................................................................................................................... 7570

ACRONYMS AND ABBREVIATIONS .................................................................................. 7570

Lists of Tables and Figures

Table 1. Calibration and maintenance requirements for water quality equipment. 1314

Table 2. Current Land-Cover Composition in the Hoh River Watershed. ............................... 2526

Table 3. Hoh River Watershed hydrologic unit descriptions. ................................................... 2829

Table 4. List of monitoring sites conducted by the Hoh Tribe’s water quality monitoring program

and their frequency and parameters. ......................................................................................... 3233

Table 5. List of monitored rivers and creeks in the Hoh River Watershed as outlined in the Hoh

River monitoring program.. ...................................................................................................... 3536

Table 6. Existing or potential pollutants throughout the Hoh River Watershed. ...................... 3738

Table 7. Historical DO and pH impairments at high-risk creeks. ............................................ 3940

Table 8. Monitoring sites in rivers and creeks of the Hoh River Watershed with impaired water

quality from FY 2021-2025 that did not fully support designated uses.................................... 4243

Table 9. Impaired waterbodies within the HRW according to the Washington Department of

Ecology’s 2022 Waterbody Assessment Cycle. ........................................................................ 4344

Table 10. Summary of results of NPS category assessment for water quality monitoring sites.

................................................................................................................................................... 5455

Table 11. Summary of potential contributors of NPS program implementation. ..................... 5556

Table 12. Summary of previous or active BMPs addressing NPS pollution sources in the Hoh

River Watershed. ....................................................................................................................... 5759

Table 13. Summary of potential NPS funding sources. ........................................................... 6466

Figure 1.The Hoh Indian Reservation is located on the mouth of the Hoh River by the Pacific

Ocean. ........................................................................................................................................... 56

Figure 2. Hoh River Watershed Land Uses with potential for NPS pollution along water quality

monitoring site waterways. ....................................................................................................... 2425

Figure 3. Land coverage of the Hoh River Watershed. ............................................................ 2627

Figure 4. Land Coverage surrounding the Hoh Indian Reservation. ....................................... 2728

Figure 5. Water quality monitoring sites in the Hoh River Watershed. Site numbers correspond to

those found in Table 4. .............................................................................................................. 3132

Figure 6. Noxious Weed Detections throughout the HRW with monitoring sites waterways

labeled. ...................................................................................................................................... 4647

OVERVIEW

This assessment report aims to evaluate nonpoint source pollution throughout the Hoh River

Watershed (HRW), which runs from multiple glaciers on Mount Olympus to the Pacific Ocean.

The Hoh Tribe’s Reservation is located off the mouth of the Hoh River. Its land base in trust and

fees only comprises approximately 1% of the entire watershed, however, the Hoh Tribe aims to

restore and protect Hoh River waterways in its entirety. The Hoh Indian Tribe retains treatyreserved hunting, fishing, and gathering rights within the Tribe’s Usual and Accustomed (U&A)

area, which includes approximately 400 square miles of land and thousands of square miles of the

Pacific Ocean. Within the U&A, the Hoh Tribe co-manages natural resources with the state of

Washington. Members of the tribe depend on natural resources within their U&A for their cultural

and economic values. Protecting and responsibly managing natural resources, such as fish,

wildlife, cedar, and berries, in the Hoh River Watershed is of the utmost importance to the Hoh

Tribe to ensure that resources are available for current and future generations to hunt, fish, and

gather, as is their treaty-reserved right.

The Hoh Tribe’s water monitoring program has collected water quality data for decades. This data

provides the basis for establishing baselines, assessing nonpoint source (NPS) pollution, and

understanding waterway impairments. HRW’s top pollutant sources are temperature, dissolved

oxygen (DO), pH, and turbidity. Potential NPS categories contributing to these water quality

impairments include forestry, roads and highways, hydromodification, atmospheric deposition,

invasives species, and natural resource extraction. These NPS categories are contributing to

pollution that are slowly reducing the river or creek’s ability to support aquatic life. This

assessment will provide evidence of our pollution through historical water quality data collection,

cultural knowledge, GIS analysis of landscape patterns, and review of historical documentation.

By documenting current conditions, identifying pollution sources, and establishing selection

criteria for management practices, this assessment creates the roadmap for transitioning from

documentation to action. The widespread and persistent impairments revealed through monitoring,

from chronic temperature exceedances to severe acidiﬁcation in some streams, demonstrate that

natural recovery processes alone cannot restore water quality within timeframes necessary to

protect treaty resources. This assessment provides the scientiﬁc justiﬁcation and strategic

framework for the comprehensive management program needed to restore and protect water

quality from nonpoint source pollution throughout the Hoh Watershed.

INTRODUCTION

The Hoh Indian Reservation encompasses 960 acres (1.5 square miles) is located at the mouth of

the Hoh River on the western coast of the Olympic Peninsula in Jefferson County, Washington.

The reservation lands, established by Presidential Executive Order on September 11, 1893, sit

where the Hoh River meets the Paciﬁc Ocean, containing 5.30 miles of rivers and streams, 1.76

miles of coastline, 2.97 acres of lakes and ponds, 19.6 acres of estuary, and 17.1 acres of swamps

and marshes. Beyond the original reservation boundaries, the Hoh Tribe has attained over 2,269

acres in trust landsbrought over 1300 additional acres into trust status. These trust lands include

the developing Highlands area near Highway 101, which represents the Tribe's commitment to

meeting housing needs while maintaining environmental stewardship. Additionally, over 400 acres

in fee lands have been added that expand tribal management authority within the watershed.

Figure 1.The Hoh Indian Reservation is located on the mouth of the Hoh River by the Pacific Ocean.

The Hoh River Watershed, a subset of the Tribe’s Usual and Accustomed Area, encompasses 298.5

square miles (191,360 acres) of the Olympic Peninsula's temperate rainforest ecosystem. The Hoh

River itself extends 56 miles from its glacial origins at Mount Olympus within Olympic National

Park to its terminus at the Paciﬁc Ocean. The river's largest tributary, the South Fork of the Hoh

River, joins the mainstem at river mile 31, approximately 0.5 miles upstream from the Olympic

National Park boundary. Throughout the watershed, a dendritic network of 1,299 miles of mapped

streams and rivers creates critical habitat for Paciﬁc salmon and other culturally signiﬁcant species.

The watershed's landscape reﬂects its position on the western slope of the Olympic Mountains,

receiving between 94 and 125 inches of annual precipitation. This extreme rainfall, among the

highest in the continental United States, drives a dynamic hydrologic regime characterized by

frequent winter ﬂooding and summer low ﬂows. Peak runoff occurs from October through March

during intense Paciﬁc storms, while minimum ﬂows typically occur in late summer. The glacially

fed nature of the Hoh River and several headwater tributaries contribute year-round ﬂow and

naturally elevated turbidity from glacial ﬂour.

Major tributaries within the reservation boundaries monitored by the Tribe include Chalaat,

Fletcher, and Braden Creeks. These tributaries range from small, spring-fed streams to substantial

rivers draining extensive sub-basins, each contributing unique water quality characteristics shaped

by local geology, land use, and management history.

The Hoh Tribe’s nonpoint source program’s goal is to identify and control nonpoint source

pollution in the Hoh Watershed to protect water quality of waterways in their usual and accustomed

area (U&A). The primary objectives implemented to achieve this goal are to comprehensively

document current water quality conditions throughout the Hoh River Watershed, identify nonpoint

source pollution categories affecting those conditions, and establish the framework for selecting

management practices to address identiﬁed problems.

Synthesis of water quality data collected through the Tribe’s CWA 106 monitoring program from

FY 2021-2025 enables identiﬁcation of both persistent impairments requiring restoration and highquality waters needing protection from future degradation. By documenting baseline conditions

across 60 monitoring sites representing diverse stream types, land uses, and management histories,

the assessment provides the scientiﬁc basis for prioritizing management actions where they will

produce the greatest water quality improvements.

Nonpoint source categories in the watershed include forestry and forest roads, hydromodiﬁcation

and bank erosion, roads and highways, atmospheric deposition, natural resource extraction, and

invasive species. The wide variety of pollution sources and land use ownerships will require

collaboration and support from public outreach and partnering organizations.

This assessment provides the technical foundation for the companion Nonpoint Source

Management Program Plan, which will establish speciﬁc goals, implementation schedules, and

funding strategies for addressing identiﬁed water quality problems. Together, these documents

fulﬁll EPA requirements while serving the Tribe's broader mission of protecting and restoring water

quality for current and future generations. The assessment represents not just regulatory

compliance but a comprehensive evaluation of watershed health that will guide management

decisions affecting treaty resources fundamental to tribal culture, economy, and identity.

METHODOLOGY

This assessment synthesizes multiple data sources to characterize water quality conditions and

identify nonpoint source pollution throughout the Hoh Watershed. Primary data derives from the

Hoh Tribe's water quality monitoring program, supplemented by spatial datasets, ﬁeld

observations, and historical documentation to provide a comprehensive watershed assessment. The

current monitoring network provides sufficient data for nonpoint source assessment with several

key strengths reinforcing assessment reliability.

The network's temporal depth, with a 30+ year temperature record, captures long-term trends

beyond natural variability cycles, enabling detection land use impacts. Spatial coverage of all

major tributaries and mainstem segments ensures no signiﬁcant source areas remain

uncharacterized. The parameter suite addresses core indicators of forestry impacts, the watershed's

primary nonpoint source category. EPA- compliant QA/QC procedures ensure defensible results

suitable for regulatory decisions. Sampling frequency exceeds minimum requirements for

statistical power, providing robust conclusions about designated use attainment. The five-year

dataset (FY 2021-2025) provides robust assessment of current conditions and recent trends,

meeting EPA requirements for NPS assessment while identifying speciﬁc waters needing

restoration and informing BMP selection.

Water Quality Monitoring Data

The primary dataset consists of water quality measurements collected through the Hoh Tribe's

EPA-approved monitoring program from FY 2021 through FY2025. This comprehensive dataset,

documented in annual CWA Section 106 reports to EPA, includes continuous temperature

monitoring at approximately 60 sites recording measurements every 15 minutes year-round,

instantaneous measurements of dissolved oxygen, pH, turbidity, and speciﬁc conductivity

collected monthly at 20 sites, continuous dissolved oxygen monitoring at 7 sites with 15-minute

recording intervals in the summer, benthic macroinvertebrate sampling at 5 sites during low flow

conditions since 2023, storm turbidity monitoring when events arise, low-ﬂow measurements

collected during summer conditions, and water chemistry sampling in 2024 at 8 sites. Historical

monitoring data extending back to 1991 provides temporal context for assessing long-term trends

and persistent impairments, with particular emphasis on temperature records that span over three

decades at core monitoring sites. Secondary datasets provide insight into temperature, DO, pH and

low flow since the early 2000s at several different creek locations.

Instantaneous Water Quality

The Hoh Indian Tribe Water Quality Monitoring Program (HWQP) has measured instantaneous

water temperature, turbidity, DO concentration, and pH in the Hoh River mainstem and selected

tributaries each month since 2005 (excluding February 2020 through June 2021; monitoring was

discontinued during this time due to COVID-19 Pandemic restrictions). Instantaneous sites were

originally chosen by finding locations with the most historical data available at the time. In 2021,

water quality parameters of DO saturation and specific conductivity were added to monthly

monitoring.

Continuous Water Temperature

The Hoh Tribe’s Department of Natural Resources has monitored water temperature continuously

in the Hoh River mainstem and its tributaries since 1991. Sites for continuous temperature

monitoring include major tributaries, minor creeks, and the Hoh River mainstem.

The network captures the range of conditions present in rivers and streams in the watershed, from

the pristine waters to the severely impaired conditions where multiple stressors create harsh

conditions for aquatic life. This comprehensive monitoring network, maintained through decades

of tribal commitment despite funding uncertainties and physical challenges, provides the

foundation for understanding and ultimately reversing nonpoint source pollution impacts

throughout the Hoh River Watershed.

Continuous Dissolved Oxygen

In summer 2020, the HWQP began continuous monitoring of DO concentration in the Hoh River

above Anderson Creek. Since then, we have added six more continuous DO sites: the Hoh River

above Barlows, the Hoh River at ONP Boundary, Lower Braden, Lower Chalaat, Hell Roaring,

and Lower Nolan Creeks. Most of these waterways were chosen because results from

instantaneous monitoring indicated that they have low DO concentrations in summer months and

may be areas of concern.

Base Flow

The HWQP has monitored summer low flow in Hoh River tributaries since the early 2000s.

Monitoring varies by year depending on staff structure, availability, and weather conditions. The

low flow period varies slightly each year in the HRW but typically occurs from late-July to lateSeptember. This work is being carried out in cooperation with the Northwest Indian Fisheries

Commission, USGS, and other contributing Western Washington Tribes. Flow data are used in

conjunction with temperature data being collected by the tribes to assess the impacts of land use

practices, water withdrawal, and landscape changes.

Water Chemistry & Total Suspended Solids

Eight creeks, Chalaat, Braden, Nolan, Owl, Elk, Winfield, Hoh Oxbow, & Hell Roaring, were

selected to conduct surface water chemistry and total suspended solids testing in 2024. These

waterways were chosen because they are suspected to have elevated water chemistry or total

suspended solids concentrations and/or they are known to be used by salmon and steelhead for

spawning, rearing, and/or migration. Grab surface water samples from rivers and creeks were

collected once a month for twelve months following methods adapted from WDOE’s Standard

Operating Procedure EAP015, version 1.4: Manually Obtaining Surface Water Samples.

Benthic Macroinvertebrates

We sample 5 creeks for benthic macroinvertebrates during baseflow conditions in August and

September 2024. Samples were taken from Anderson, Owl, Elk, Nolan, and Winfield Creeks.

These creeks were chosen because they are used by salmon and steelhead for spawning, rearing,

and migration. We also collect a replicate sample from one creek, which is randomly chosen, to

assess the within-site variability of the samples. The replicate sample was collected right after the

primary sample and within the same sampling reach.

Samples were collected on days without any rain events. Eight digs were completed in each reach

(two per riffle, total kick area of eight-square feet per sample) using a surber sampler with a 500micron (μm) mesh size. Samples were subsampled to 500 individuals and identified to lowest

practical taxonomic level by Aquatic Biology Associates, a taxonomic laboratory.

Equipment

Current monitoring employs EPA-approved methods with standardized equipment ensuring data

quality and comparability across programs. To get meaningful data, it is necessary to use

equipment with the proper sensitivity, or the lowest detection limit for each measurement type. For

data to be used for Washington state’s Water Quality Assessment process, sensors must have a

sensitivity below the applicable water quality criterion. Benthic macroinvertebrate samples must

be subsampled and identified in a manner that provides meaningful information about the

community assemblage and water quality of the waterway. The equipment and methods used by

the HWQP are as follows:

Instantaneous water quality: The YSI ProDSS serves as the primary ﬁeld instrument for monthly

monitoring with advanced features that improve both data quality and ﬁeld efficiency. It consists

of a handheld meter, a cable, and a connected bulkhead with temperature/conductivity, optical

dissolved oxygen (ODO), pH, and turbidity sensors. The YSI ProDSS multimeter has sensors with

sensitivities of:

• Temperature: -5 ºC

• DO: 0 mg/L

• pH: 0

• Specific conductivity: 0 mS/cm

• Turbidity: 0 FNU

Continuous water temperature: The Onset HOBO TidbiT MX Temperature 400 and Temperature

Pro v2 are used to monitor continuous temperature every 15 minutes throughout the year. The

Onset HOBO TidbiT MX Temperature 400’ logger has a sensitivity of -20 °C in air or water. The

Onset HOBO Temperature Pro v2 logger has a sensitivity of - 40 °C in air or water.

Continuous dissolved oxygen: The Onset HOBO DO logger measures dissolved oxygen between

0-30 mg/L with an accuracy of ± 0.2 mg/L up to 8 mg/L; ± 0.5 mg/L from 8 to 20 mg/L.

Low Flow: The OTT MF Pro calculates flow measurements according to USGS and ISO methods.

The electromagnetic velocity sensor has an accuracy velocity range of 0 - 10 ft/s: ± 2 % of reading

± 0.05 ft/s Reading 10 - 16 ft/s: ± 4 % of reading.

Benthic Macroinvertebrates: Benthic macroinvertebrates are collected from wadable creeks

following methods from the Streamkeepers of Clallam County Field Procedures (2018) manual.

Equipment includes 500 micron sieves, denatured alcohol and surber sampling set.

Water chemistry and total suspended solids concentrations: Sensitivity of water sample analyses

methods is reported with the method detection limit, or the minimum concentration of an analyte

in a sample that can be reported with 99% confidence. The method detection limits for water

samples analyzed for water chemistry and total suspended solids concentrations are:

• Total Kjeldahl nitrogen: 0.2 ppm

• Nitrate + nitrite-N: 0.1 ppm

• Ammonia-N: 0.01 ppm

• Total phosphorus: 0.01 ppm

• Ortho-phosphate: 0.01 ppm

• Dissolved organic carbon: 0.095 ppm

• Total suspended solids: 4 ppm

Quality Assurance/Quality Control Protocols

To be considered usable, water quality data must conform to certain quality requirements presented

in the Hoh Tribes EPA-approved QAAP. Below are a list of objectives the equipment and sampling

undergo to maintain proper quality control measures.

•

Data are precise, with measurements being repeated consistently.

o Instantaneous water quality: Duplicate measurements of each water quality

parameter are taken at each site. If it appears that measurements are not precise,

then the YSI ProDSS multimeter will be recalibrated.

o Benthic Macroinvertebrates: Each year, a replicate sample will be taken from one

randomly chosen site to assess within-site variability.

o Water chemistry and total suspended solids concentration: Duplicate water samples

for analysis of each water quality parameter are taken at each site.

•

Bias of data is reduced as much as possible.

o Instantaneous water quality and storm turbidity: Instantaneous water quality is

measured each month at sites across the Hoh River watershed to capture a wide

range of conditions. Sites include those with relatively pristine (in the ONP) and

degraded (out of the ONP) water quality to reduce bias towards either type of site.

o Continuous water temperature: Continuous water temperature is recorded at sites

across the Hoh River watershed to capture a wide range of conditions. Sites include

those with relatively pristine (in the ONP) and degraded (out of the ONP) water

quality to reduce bias towards either type of site. In the Hoh River, loggers are

sometimes placed in side channels, which may result in main channel temperatures

being missed.

o Continuous dissolved oxygen: Continuous dissolved oxygen is recorded at sites

outside of the ONP (more degraded). Sites were chosen because results from

instantaneous water quality monitoring indicated that they had low DO

concentrations. Data are likely skewed. In the Hoh River, loggers are sometimes

placed in side channels, which may result in main channel DO concentration being

missed.

o Low Flow: Low flow is measured in creeks outside of the ONP and at a small

number of sites. Data are likely skewed and not representative of the entire Hoh

River watershed.

o Benthic Macroinvertebrates: Benthic macroinvertebrates are sampled at a small

number of sites. Data are likely skewed to reflect localized conditions instead of

the entire Hoh River watershed.

o Water chemistry and total suspended solids concentration: Grab samples for water

chemistry and total suspended solids concentrations are mainly located outside of

the ONP (more degraded). Most sites were chosen because results from

instantaneous water quality monitoring indicated that they may have elevated water

chemistry and/or total suspended solids concentrations.

•

Data are representative of the area from which they are measured.

o Instantaneous water quality and storm turbidity: Instantaneous water quality and

storm turbidity are measured at sites across the Hoh River watershed to capture a

wide range of conditions. Sites include those with relatively pristine (in the ONP)

and degraded (out of the ONP) water quality. Instantaneous water quality is

monitored once a month to capture conditions throughout the year.

o Continuous water temperature: Continuous water temperature is recorded at sites

across the U&A to capture a wide range of conditions. Sites include those with

relatively pristine (in the ONP) and degraded (out of the ONP) water quality to

reduce bias towards either type of site. At select sites, water temperature is

monitored through the entire year to capture seasonal variation in temperature. Sites

where monitoring is only done during the summer do not properly reflect conditions

throughout the entire year.

o Continuous dissolved oxygen: Continuous dissolved oxygen is recorded at sites

outside of the ONP (more degraded). Sites were chosen because results from

instantaneous water quality monitoring indicated that they likely had low DO

concentrations. Data are likely not representative of conditions throughout the

entire watershed. Results do not capture conditions throughout the year because

continuous dissolved oxygen is only monitored in the summer.

o Low Flow: Low flow is measured in creeks outside of the ONP (more degraded)

and at a small number of sites. Data are likely skewed and not representative of the

entire U&A.

o Benthic Macroinvertebrates: Benthic macroinvertebrates are sampled at a small

number of sites. Data are likely not representative of the entire Hoh River

watershed.

o Water chemistry and total suspended solids concentration: Grab samples for water

chemistry and total suspended solids concentrations are collected outside of the

ONP (more degraded). Most sites were chosen because results from instantaneous

water quality monitoring indicated that they may have elevated water chemistry

and/or total suspended solids concentrations. Data are likely not representative of

the entire Hoh River watershed.

•

Data are collected in a manner that they are comparable to other datasets.

o Instantaneous water quality and storm turbidity: The YSI ProDSS multimeter is

calibrated and maintained following QAPP protocols and the manufacturer’s

recommendations.

o Continuous water temperature: Onset Hobo temperature loggers are maintained

following QAPP protocols and the manufacturer’s recommendations. The accuracy

of each logger is checked using the QAPP protocol prior to deployment.

o Continuous dissolved oxygen: Onset Hobo DO loggers are calibrated and

maintained following QAPP protocols and the manufacturer’s recommendations.

o Low Flow: The MF Pro flow meter and velocity sensor are calibrated and

maintained following QAPP protocols and the manufacturer’s recommendations.

Data are collected following QAPP protocols.

o Benthic Macroinvertebrates: Benthic macroinvertebrates are sampled following

QAPP protocols.

o Water chemistry and total suspended solids: Water samples are collected following

QAPP protocols.

•

Data are measured with sensors with the appropriate sensitivity to answer the questions

that are being posed.

o To get meaningful data, it is necessary to use equipment with the proper sensitivity,

or the lowest detection limit for each measurement type. For data to be used for

Washington state’s Water Quality Assessment process, sensors must have a

sensitivity below the applicable water quality criterion. Benthic macroinvertebrate

samples must be subsampled and identified in a manner that provides meaningful

information about the community assemblage and water quality of the waterway.

Equipment is calibrated to ensure accuracy and precision of respective parameters frequently to

ensure quality data. Calibration standards are purchased directly from the instruments supplier and

are regularly verified for expiration and reliability. Along with routine calibration by the Water

Quality Specialist, Onset HOBOware, YSI ProDSS multiparameter and MF Pro Flow meters are

sent to the manufacturer service center for inspection and, if necessary, replacement of parts and

calibration (Table 1).

Table 1. Calibration and maintenance requirements for water quality equipment.

Instrument/

Equipment

Onset HOBO

Pro V2

temperature

logger

Onset HOBO

TidbiT MX

temperature

400’ logger

Onset HOBO

DO logger

YSI ProDSS

multimeter

with fourport cable

assembly

OTT MF Pro

flow meter

and velocity

sensor

Calibration/ Verification

Method

• Temperature verification

against a NIST-certified

thermometer in an ice

bath and in room temp

water

• Temperature verification

against a NIST-certified

thermometer in an ice

bath and in room temp

water

• Replace sensor cap yearly

and calibrate 100%

saturation in watersaturated air and adjust

for elevation and pressure

• 3pt calibration using pH

4, 7, 10 buffer solutions

• Temperature verification

against a NIST-certified

thermometer

• Calibration with 1000

µS/cm conductivity

standard

• 2 or 3 pt calibration using

0, 12.4,124, or 1010 FNU

turbidity standards

• DO saturation calibration

using in water-saturated

air

• Send to OTT Repair

Center once a year for

calibration of sensors.

Calibration Frequency

Maintenance

Requirements

Per manufacturer’s

instructions

•

Check accuracy of logger

prior to summer

deployment.

•

Calibrate sensor after

replacing DO cap prior to

summer deployment.

•

Per manufacturer’s

instructions

•

Check accuracy of logger

prior to summer

deployment.

•

Per manufacturer’s

instructions

•

Check accuracy of

temperature sensor on day

of monitoring prior to use.

Calibrate pH and DO

sensors on day of

monitoring prior to use.

Check accuracy of turbidity

and specific conductivity

sensors on day of

monitoring prior to use. If

needed, calibrate sensors.

Send to YSI Repair Center

once a year for calibration

of sensors.

Send to OTT Repair Center

once a year for calibration

of sensors.

•

Per manufacturer’s

instructions.

Send to YSI

Repair Center once

a year for

inspection for

malfunctions and

repairs, including

replacement of

ODO cap and pH

module.

•

Per manufacturer’s

instructions.

Send to OTT

Repair Center once

a year for

inspection for

malfunctions and

repairs.

Data collection methods follow strict protocols outlined in the Tribe’s Quality Assurance Project

Plan (QAPP). This ensures standard operating procedures are in place to attain quality and avoid

data errors. Protocols are based on known and effective methodologies from NWIFC, USGS,

neighboring Western Washington Tribes, WDOE, WDNR, and Streamkeepers of Clallam County.

To ensure proper data management, data are recorded in field notebooks or the appropriate field

form when any measurement is conducted. When field data are collected, the site name, date, time,

and GPS location are also recorded. When paper field forms are used, they are scanned to pdf

format. Data are then entered into Excel files. When data are initially saved as digital forms on an

electronic device (e.g., continuous data in a HOBOfile downloaded from an Onset data logger),

the data are automatically converted to Excel files. All files containing data are stored in an

electronic project folder. Copies of this folder are kept on the Water Quality Specialist’s PC, the

Hoh Tribe’s centralized computer system, and a removable hard drive. After data have been

reviewed for anomalies and transcription errors, data are imported into the Hoh Tribe’s Tribal

Water Quality Database (TWQD) and the Water Quality Time Series (WQTS) database in

Microsoft SQL server. Backups of the TWQD and WQTS are saved onto the Water Quality

Specialist’s computer and external hard drive whenever changes are made to the databases.

Finalized data in TWQD are submitted to the EPA Water Quality Exchange (WQX) using the

Tribal Water Quality Exchange Client, an exchange network node developed by the NWIFC.

The Hoh Tribe does not have water quality standards for fresh surface waters. Therefore, tribal

goals for rivers and creeks in the watershed are based on Washington State fresh water designated

aquatic life uses (WAC 173-201A-200 freshwater designated uses and criteria, 2020). Designated

aquatic life uses describe the ways in which a waterbody is used by aquatic organisms during their

life cycles. Each designated use has limits, or “criteria”, for certain water quality parameters (i.e.,

temperature, DO, pH). If a water quality measurement of a waterway exceeds criteria, then the

water quality is degraded enough to hinder aquatic life growth, reproduction, and/or survival.

Geospatial Data Sources

Spatial analysis employed federal and state datasets to characterize watershed features and land

use patterns. The National Wetlands Inventory supplied wetland mapping including type,

hydrogeomorphic classification, and regulatory status. Rivers and streams data came from the

National Hydrography Dataset, offering complete stream network topology with ﬂow direction

and stream order attributes.

Roads data from Topologically Integrated Geographic Encoding and Referencing (TIGER)

Shapeﬁles provided transportation network geometry including road classiﬁcation and surface

type. Elevation data from the Washington State Geospatial Open Data Portal enabled derivation of

slope, aspect, ﬂow direction, and ﬂow accumulation, supporting complete watershed delineation.

The WADOE Water Quality Atlas supplied 303(d) impaired waters listings with parameter-speciﬁc

impairment designations.

Geospatial analysis employed ArcGIS Pro with Spatial Analyst extension to integrate diverse

datasets, identify pollution sources, and quantify landscape-water quality relationships. Land use

and land cover data from the Jefferson County Public Land records.

All spatial data were projected to NAD 1983 State Plane Washington North FIPS 4601 (US Feet)

to maintain geometric accuracy and enable precise overlay analysis. This projection minimizes

distortion across the watershed while maintaining compatibility with state and regional datasets.

Transformations between datums employed the NAD 1927 to NAD 1983 NADCON

transformation for historical data integration.

The watershed was delineated using 10-meter Digital Elevation Model (DEM) data through

systematic terrain processing. Flow direction was calculated using D8 algorithm identifying

steepest descent from each cell. Flow accumulation quantiﬁed upstream contributing area for

stream network deﬁnition. Stream networks were extracted at 25-acre accumulation threshold

calibrated to match NHD ﬂowlines. Watershed boundaries were delineated from the Hoh River

mouth pour point, capturing all contributing drainage. Sub-watershed boundaries at HUC-12 scale

enabled localized analysis of pollution sources and impairment patterns.

Spatial overlay analysis identiﬁed potential nonpoint source pollution delivery pathways by

intersecting land use, infrastructure, and water resources. Analysis parameters included roads

within 100 feet of streams on slopes exceeding 10%, harvest units from 2015-2025 within 300 feet

of ﬁsh-bearing streams, residential parcels lacking 50-foot riparian buffers, and stream crossing

locations. While comprehensive GIS quantiﬁcation exceeded the scope of this assessment, the

methodology established the framework for identifying pollution delivery pathways.

Despite these assumptions, the assessment provides sufficient information to identify priority

waters needing restoration, characterize major nonpoint source categories, and establish a

framework for BMP selection. The combination of long-term monitoring data, comprehensive

spatial analysis, and extensive historical documentation creates a robust foundation for the

Nonpoint Source Management Program. Acknowledged uncertainties are addressed through

adaptive management approaches that incorporate effectiveness monitoring and periodic

reassessment as additional information becomes available.

Historical Documentation

Historical documents reviewed included the Environmental Assessment for the Highlands

Development (2024) documenting pre-development conditions and infrastructure plans, multiple

Phase I Environmental Site Assessments identifying potential contamination sources including

historical land uses, wetland delineations and stream assessments establishing baseline habitat

conditions and regulatory jurisdictions, diesel spill response monitoring following incidents near

Chalaat Creek and Highway 101, and the Upper Hoh Road water quality assessment with monthly

sampling at six stations. The Hoh Tribe's Non-Expiring Forest Management Plan and

accompanying Environmental Impact Statement provided forest management standards and

harvest projections affecting water quality. Regional assessments including WRIA 20 watershed

planning documents and Olympic National Park monitoring reports offered watershed-scale

context for local observations.

Limitations & Assumptions

This assessment acknowledges inherent limitations in data availability, analytical methods, and

jurisdictional constraints that inﬂuence conclusions and recommendations.

The dynamic nature of the Hoh River system presents signiﬁcant monitoring challenges that affect

data completeness and program costs. Seasonal access constraints affect data collection throughout

the year. Winter storms make roads impassable from December through February, snow blocks

upper elevation sites from November through April, and high ﬂows prevent safe wading from

November through May. These limitations create temporal bias, with summer data overrepresented

relative to winter conditions when different water quality dynamics occur. Headwaters above

3,000 feet in elevation remain largely unmonitored due to access constraints and snow limiting

deployment windows. Non-ﬁsh tributaries receive lower priority given limited resources, though

they contribute ﬂow and potentially pollutants. Wetlands require different protocols than stream

monitoring, remaining largely uncharacterized despite their inﬂuence on pH and dissolved oxygen.

LAND USE SUMMARY

The Hoh River Watershed encompasses diverse land cover types that collectively inﬂuence

nonpoint source pollution generation and transport pathways. Forest lands dominate the landscape,

comprising 81.6% of the total watershed area. This forested landscape creates both the watershed's

exceptional baseline water quality and its primary nonpoint source challenges through forest

management activities.

Forest Lands

Coniferous forest represents the watershed's dominant land cover, with evergreen forest

comprising 112,742 acres (58.89% of the watershed), extending from sea level to alpine zones

across multiple ownership categories. Within Olympic National Park's (ONP) 109,888 acres

(57.4% of the watershed), intact old-growth forests that create headwater conditions that maintain

exceptional water quality in the upper watershed. These protected forests, some containing trees

exceeding 1,000 years in age, provide an ecological benchmark against which downstream impacts

are measured.

A large portion of the Hoh River flows through a temperate rainforest. Dominant tree species are

western hemlock (Tsuga heterophylla), Sitka spruce (Picea sitchensis), black cottonwood (Populus

trichocarpa), big-leaf maple (Acer macrophyllum), red alder (Alnus rubra), willow species (Salix

spp.), western red cedar (Thuja plicata), Pacific silver fir (Abies amabilis), and Douglas fir

(Pseudotsuga menziesii). Obligate wetland plant species often found in the watershed include

slough sedge (Carex obnupta), water parsley (Oenanthe sarmentosa), and western skunk cabbage

(Lysichiton americanus). Invasive plant species, such as spotted jewelweed (Impatiens capensis),

Japanese knotweed (Fallopia japonica), scotch broom (Cytisus scoparius), and reed canary grass

(Phalaris arundinacea) persist within floodplain and riparian zones. Spread of invasives is

associated with reduced river bank stabilization and loss of water from the channel, which pose

major threats to instream ecosystems.

Outside the park boundaries, managed forests on state and private lands display a complex mosaic

of harvest units and regenerating stands at various stages of succession. Timber harvest operations

are extensive throughout the watershed, with clearcuts of varying ages along Highway 101, the

Hoh Mainline Road, and Oil City Road. These harvest units displayed distinct age classes that

reﬂect decades of continuous forest management: fresh clearcuts less than one year old with

exposed soil and logging debris, recent harvests between one and ﬁve years old showing early

regeneration (including a documented 5-year- old clearcut observed near the Elk Creek monitoring

station), mid-rotation stands of ﬁve to ﬁfteen years displaying closed canopy conditions, and

maturing second growth exceeding ﬁfteen years approaching commercial thinning age. A recently

harvested clearcut was documented immediately adjacent to the west side of Anderson Creek,

demonstrating the proximity of active forest management to water quality monitoring sites.

Spatial distribution of these harvest units correlates strongly with documented water quality

impairments. Washington Department of Natural Resources manages 46,464 acres (24.3% of the

watershed) as state trust lands, while private industrial and non-industrial forest lands encompass

33,600 acres (17.6%), including 10,315 acres under management by The Nature Conservancy

(Figure 2). The 960-acre Hoh Indian Reservation (0.5% of the watershed) maintains limited forest

management primarily for cultural uses. These actively managed forests outside the park, while

providing economic beneﬁts through timber production, create the primary source areas for

sediment delivery, thermal pollution, and invasive species establishment affecting downstream

waters. The intensity of management varies by ownership, with industrial forests typically

harvested on 35–45-year rotations while state lands follow longer 60-80 year rotations, creating a

patchwork of forest conditions across the landscape.

Recently harvested and regenerating areas display clear successional patterns across the landscape.

GIS analysis reveals that shrub/scrub vegetation representing the most recent clearcuts (0-5 years

old) encompasses 10,620 acres (5.55% of the watershed), while deciduous forest dominated by

red alder colonizing older harvest units (5-20 years old) covers 38,962 acres (20.35% of the

watershed). Combined, these early successional stages total 49,582 acres (25.9% of the watershed)

(Figure 3), conﬁrming ﬁeld observations of extensive recent timber harvest activity. Disturbance

of these areas opens opportunities for invasive species to develop in place of native, large growth

trees.

These areas concentrate along major transportation corridors where access facilitates timber

extraction. Harvest rotation ages have evolved signiﬁcantly from traditional practices, with

maximum ages now ranging from approximately 90 years on high-quality sites to 117 years on

lower-quality sites based on US Forestry Service (USFS) Paciﬁc Northwest Research Station

extended rotation research. This evolution toward longer rotations reﬂects growing recognition of

the multiple values forests provide beyond timber production.

Mixed forest areas occupy 4,516 acres (2.36% of the watershed), occurring primarily in riparian

zones and transitional areas between coniferous and deciduous stands. Red alder (Alnus rubra)

dominates the deciduous component, particularly in riparian areas and recently disturbed sites

where its nitrogen-ﬁxing capability accelerates soil development. Bigleaf maple (Acer

macrophyllum) occurs as a subdominant species, providing rapid shade recovery along stream

corridors critical for temperature regulation. These hardwood-dominated stands, while

representing a smaller portion of total forest cover, provide disproportionate ecological beneﬁts

through nitrogen ﬁxation, rapid growth rates that quickly restore canopy cover, and high-quality

leaf litter that supports aquatic food webs.

Commercial timber harvest has persisted as the dominant land use activity affecting water quality

throughout the watershed's state and private forest lands over the past decade. While tribal forest

lands continue to be managed under sustained yield principles that prioritize cultural values and

salmon habitat protection, the surrounding industrial and state forests have maintained active

harvest programs that create ongoing nonpoint source pollution challenges.

The Olympic Experimental State Forest's 270,000 acres on the western Olympic Peninsula has

emerged as a living laboratory for evolving forest management approaches that may inﬂuence

practices throughout the Hoh watershed. Research conducted there has documented a fundamental

shift in silvicultural philosophy, with harvest rotation ages extending from traditional 45–60-year

industrial cycles to 90-117 years under extended rotation strategies developed by the USFS Paciﬁc

Northwest Research Station. Maximum rotation ages now range from approximately 90 years on

high-quality sites to 117 years on lower-quality sites, with peer-reviewed studies demonstrating

that rotations can be "considerably extended without reducing long-term timber production”

(Curtis 1995). This paradigm shift reﬂects growing recognition that forests managed for multiple

values, including wildlife habitat, carbon sequestration, and water quality protection, can maintain

economic viability while reducing environmental impacts.

Post-harvest regeneration throughout the watershed follows predictable Olympic Peninsula

succession patterns, though speciﬁc stocking levels and species composition data remain

proprietary to individual landowners. Natural regeneration by red alder (Alnus rubra) dominates

riparian-adjacent harvest units, providing nitrogen ﬁxation and relatively rapid canopy closure that

partially mitigates temperature. However, the conversion from complex old-growth and mature

second-growth forests to simpliﬁed even-aged plantations represents a fundamental alteration of

watershed processes that affect water quality for decades following harvest.

The spatial distribution of harvest activity over the past decade may contribute with persistent

water quality impairments documented through the Tribe's monitoring program. The FY25

monitoring found 26 sites across the Hoh River, South Fork Hoh River, and 22 tributaries impaired

due to elevated temperatures, affecting 35.8 river miles or 47.2% of the total monitored stream

length (Hoh FY25 Water Quality Assessment Report, 2025). This represents a troubling expansion

from earlier assessments. Current aerial imagery available through Google Earth and NAIP reveals

visible harvest patterns that align with these temperature-impaired drainages, suggesting a

relationship between canopy removal and thermal pollution.

Developed Lands

Development within the watershed concentrates in speciﬁc zones that create localized but

signiﬁcant water quality impacts. GIS analysis of 2021 NLCD data reveals that developed areas,

including residential, commercial, and transportation infrastructure, comprise 7,463 acres (3.90%

of the watershed). Despite this relatively small footprint, the concentration of impervious surfaces

and human activities in these areas can generate disproportionate pollutant loads that affect

downstream water quality, especially with heavy traffic stemming from the ONP.

Residential

The Lower Hoh community represents the primary concentration of development within tribal

lands, encompassing the 960-acre Hoh Indian Reservation at the river mouth where tribal members

maintain their ancestral connection to the watershed. This community beneﬁts from modern

wastewater infrastructure, which serves tribal homes and administrative buildings. The Tribe’s

municipal-style treatment system represents a signiﬁcant investment in water quality protection,

preventing the nutrient and pathogen loading that would occur from individual on-site septic

systems.

Residential growth within the watershed has proceeded at a modest but steady pace, though at rates

signiﬁcantly lower than broader Jefferson County trends would suggest. While Jefferson County's

population increased from approximately 30,000 residents in 2014 to 34,000 in 2025 (USA Facts

2026), representing a compound annual growth rate of 1.1%, most of this growth occurred on the

eastern side of the Olympic Peninsula in communities like Port Townsend and Quilcene. The Hoh

Watershed on the western slope contains only a small fraction of the county's population, with

most residents concentrated in the Lower Hoh community and scattered rural properties along

transportation corridors. The watershed's geographic isolation and limited services, suggests

development pressure remains minimal compared to many Paciﬁc Northwest watersheds.

However, the cumulative effects of even modest development in a largely undeveloped watershed

create water quality impacts that persist for decades.

Commercial

Tourism infrastructure has experienced dramatic growth pressure, with Olympic National Park

visitation at 3.5 million annual visitors generating 565,706 vehicle trips along Highway 101 in

2025 (National Park Service, 2026). This tourism surge creates seasonal stress on transportation

systems, with one-to-two-hour entrance delays during peak periods indicating infrastructure

capacity limitations. The economic importance of tourism drives pressure for infrastructure

improvements that may conﬂict with water quality protection goals.

The emergency repairs needed on Upper Hoh Road exemplify how increasing storm intensity

overwhelms infrastructure designed for historical conditions. Projected increases in atmospheric

river events, rain-on-snow occurrences, and peak ﬂow magnitudes suggest that existing

infrastructure will face accelerating stress, potentially creating new pollution sources as systems

fail. The observed bank stabilization challenges, requiring massive dolosse structures and ongoing

multi-mile armoring projects, indicate that geomorphic changes are already exceeding

infrastructure adaptive capacity.

Transportation

The watershed's transportation network continues to serve as a chronic source of sediment and

toxic chemicals while providing essential access for local residents, the annual visitors to Olympic

National Park and the forest management activities that support regional economies.

Highway 101 serves as the watershed's primary transportation artery and most signiﬁcant linear

source of nonpoint pollution, extending 366 miles through Washington State while bisecting tribal

lands to provide the only year-round access route to the outer Olympic Peninsula coast. This

heavily traveled corridor generates continuous water quality impacts through multiple mechanisms

that compound across its length. Many river and stream crossings, such as the Highway 101 old

trestle bridge over the Hoh River, have no stormwater control infrastructure, resulting in traffic

and road stormwater ﬂowing directly into the waterways. This complete absence of treatment

infrastructure allows road runoff contaminated with tire particles, petroleum hydrocarbons, heavy

metals, and winter de-icing materials to discharge directly into waters that support threatened

salmonid populations. Emissions from vehicle exhaust or hazardous material combustion can

reach waterbodies through proximity and aerial dispersal. High mercury concentrations, attributed

to vehicle emissions, have already been detected in snow and fish in the Olympics (Eagles-Smith

et al. 2014). Waterbodies are directly affected through rainwater runoff; however, particulates also

get distributed to soil through lichen absorption or forest debris (Maynes 2008). This insinuates

long-term adsorption from soil, even if roads are no longer in use. Elevated mercury concentrations

pose hazards to aquatic life species and human health.

Upper Hoh Road exempliﬁes the escalating challenges of maintaining essential transportation

infrastructure in a dynamic river environment while attempting to minimize water quality impacts.

It provides the critical access route from Highway 101 to Olympic National Park's Hoh Rainforest

visitor center and represents another signiﬁcant infrastructure corridor. This road serves the

460,000 annual visitors who entered the park in 2024, with 176,566 vehicles sometimes creating

one-to-two-hour entrance wait times during peak periods (National Park Service, 2026).

In 2021, Western Federal Lands Highway Division built a massive erosion control barrier along

the north bank between the road and the river to protect Upper Hoh Road from the river's erosive

force. This barrier incorporates traditional riprap and logs but relies primarily on dolosse—

specialized concrete erosion control structures typically used in coastal engineering—placed in

large piles along the bank between the river and road. The presence of these massive concrete

forms, each weighing several tons, indicates erosion pressures that exceeded conventional

engineering solutions. The current 12-mile bank stabilization project underway through the

Western Federal Lands Highway Division represents a multi-million-dollar investment attempting

to protect the road into the Olympic National Park from destruction, though the long-term viability

of armoring approaches remains questionable under the extreme migration of the Hoh River. The

Tribe’s Natural Resource Department is aiding in long-term research monitoring to assess the

effectiveness of this project. This project demonstrates the ongoing challenge of maintaining

transportation infrastructure in this dynamic river environment while minimizing water quality

impacts. The road's importance to both tourism and emergency access was highlighted by the need

for $650,000 in emergency repairs at milepost 9.9 in May 2025, funded through Washington State

Strategic Reserve funds.

The Hoh Mainline Road, anchored at its Highway 101 intersection where a former lumber mill

once processed the watershed's timber harvest, continues providing access to extensive forest lands

and rural properties throughout the middle watershed. While receiving less traffic than Upper Hoh

Road, this route's proximity to active forest management areas creates chronic sediment delivery

at numerous stream crossings. The road's gravel surface generates ﬁne sediment during dry

conditions and concentrated erosive ﬂows during storms, creating year-round water quality

impacts that affect downstream beneﬁcial uses.

Jefferson County's maintenance responsibility for 400 center-line miles of secondary roadway plus

8.4 miles of multi-use trails creates an extensive secondary transportation network that generates

cumulative water quality impacts through distributed pollution sources. Secondary roads within

the watershed primarily serve residential properties and provide natural resource access, creating

moderate but persistent traffic that mobilizes pollutants year-round.

Forest roads constructed primarily for timber harvest access create the watershed's most extensive

transportation infrastructure, forming a dendritic network throughout the approximately 70,864

acres of state and private commercial forest lands. These roads, while essential for forest

management operations, represent chronic sediment sources that persist long after harvest

activities cease. Many forest road stream crossings, including single-lane wooden bridges at Maple

Creek and Owl Creek Upper monitoring stations, act as nonpoint sources of sediment runoff during

precipitation events.

Washington Department of Natural Resources road management has shifted from expansion

toward strategic decommissioning and maintenance optimization, reﬂecting recognition that road

density correlates directly with water quality degradation. Regional studies indicate that properly

functioning watershed conditions require road densities below 2 miles per square mile, with

sensitive species like bull trout often absent where densities exceed 1.5 miles per square mile (Lyon

& Maguire, 2008).

Agricultural and Open Lands

Agricultural lands and pastures represent a minor land use within the watershed. GIS analysis

reveals that agricultural uses account for 765 acres (0.40% of the watershed), consisting primarily

of hay and pasture lands. Pastoral landscapes dot the Upper Hoh Road, including relatively large

areas of pastureland along the north side of the road with several large open ﬁelds enclosed by

grazing fences. These agricultural areas occur primarily in valley bottoms where gentler slopes

and deeper soils support pasture establishment, with most operations appearing to be small-scale

livestock grazing and hay production based on aerial imagery interpretation.

Grasslands and open areas not in active agricultural production comprise 5,128 acres (2.68% of

the watershed) according to GIS analysis. These areas include natural meadows maintained by

periodic ﬂooding or poor drainage, utility corridors requiring vegetation management for power

line clearance, road rights-of-way maintained in herbaceous vegetation, and other open land types

visible in current aerial imagery. While individually small, these openings in the forest canopy

create edge effects and can concentrate surface runoff during precipitation events.

Other Land Cover Categories

Barren lands throughout the watershed, including exposed river gravels, landslide scars, and rock

outcrops, represent 670 acres (0.35% of the total area). The Hoh River's active channel migration

zone creates the most extensive barren areas, with dynamic patterns of gravel bar formation and

vegetation colonization visible in sequential aerial imagery. The river's characteristic milky slateblue coloration, produced by glacial ﬂour from the Blue, White, and Lateral Glaciers in the upper

watershed, indicates active erosion of bedrock that maintains sediment supply to these depositional

features. These naturally barren areas, while appearing disturbed, represent essential components

of the river ecosystem, providing spawning gravels for salmonids and nesting habitat for

specialized bird species.

The distribution of land ownership within the watershed creates distinct management zones that

fundamentally inﬂuence water quality protection approaches (Figure 2). The majority of the upper

basin is under federal preservation status that prohibits commercial resource extraction, providing

better headwater protection compared to some Olympic Peninsula watersheds. The ownership

maps (Figures 2 - 4) illustrate the complex checkerboard pattern of state and private forest lands

in the lower and middle watershed that creates coordination challenges for implementing

consistent management practices, while the upper watershed's consolidated federal ownership

enables uniform preservation standards.

The Hoh Tribe has strategically expanded its land base through acquisition of additional trust lands

beyond the reservation boundary, enhancing the Tribe's capacity to implement comprehensive

watershed protection measures. These acquisitions, focused on culturally signiﬁcant areas and

critical habitat, demonstrate the Tribe's long-term commitment to ecosystem restoration and

protection.

The current land cover composition, shaped by geology, landscape, and human management over

millennia, creates both the watershed's exceptional ecological values and its vulnerability to

nonpoint source pollution. The dominance of forest cover maintains base water quality conditions

superior to more developed watersheds, yet the intensity of forest management on portions of the

landscape generates chronic and acute water quality impacts. Understanding this complex mosaic

of land covers and their associated management regimes provides the foundation for developing

targeted strategies to protect and restore water quality throughout the Hoh River Watershed.

Figure 2. Hoh River Watershed Land Uses with potential for NPS pollution along water quality monitoring site waterways.

Table 2. Current Land-Cover Composition in the Hoh River Watershed.

Land Cover Type

Acres

Percentage

Primary Locations

Evergreen Forest

112,742

58.89%

Throughout watershed

Deciduous Forest

38,962

20.35%

Riparian areas, harvest regrowth

Mixed Forest

4,516

2.36%

Transitional zones

Shrub/Scrub

10,620

5.55%

Recent harvest areas

Grassland/Herbaceous

5,128

2.68%

Meadows, clearings

Pasture/Hay

765

0.40%

Valley bottoms

Woody Wetlands

7,425

3.88%

Throughout

Emergent Wetlands

631

0.33%

Lowland areas

Open Water

2,469

1.29%

Rivers and streams

Developed Open Space

6,257

3.27%

Lower Hoh area

Developed Low Intensity

1,072

0.56%

Rural residential

Developed Medium

Intensity

0.05%

Commercial areas

Developed High Intensity

0.02%

Dense development

Barren Land

670

0.35%

River gravels

Total

191,391

100%

Source: GIS analysis of 2021 National Land Cover Database (NLCD)

Figure 3. Land coverage of the Hoh River Watershed.

Figure 4. Land Coverage surrounding the Hoh Indian Reservation.

SURFACE AND GROUND WATER QUALITY

Hoh Indian Reservation

The 1.5-square mile (960-acre) Hoh Indian Reservation is located on the Olympic Peninsula in

Jefferson County, Washington (Figure 1). The reservation, which sits by the mouth of the Hoh

River on the Pacific Coast, contains a variety of freshwater and saltwater sources, including 5.30

miles of rivers and streams, 1.76 miles of coastline, 2.97 acres of lakes and ponds, 19.6 acres of

estuary, and 17.1 acres of swamps and marshes. Tribal residents receive potable water from one

major aquifer system. Wastewater is treated at a plant on the reservation that was installed in 2018.

The Hoh River originates at glacial terminuses on Mount Olympus in the Olympic National Park,

flowing 56 miles from its headwaters to the Pacific Ocean. Due to the glacially-fed nature of the

Hoh River and several of its headwater tributaries, glacial till gives the river high background total

suspended sediment concentrations. Numerous tributaries enter the river as it flows towards the

coast; in total, there are 1,299 miles of creeks and rivers within the HRW comprised of seven

different hydrologic units (Table 3). The South Fork of the Hoh River, the river’s largest tributary,

joins the mainstem near river mile 31, approximately 0.5 miles upstream from the ONP boundary.

Waterways within the Hoh Tribal trust and fees land include Chalaat, Braden, and Fletcher Creek.

Table 3. Hoh River Watershed hydrologic unit components and descriptions.

Name

Headwaters Hoh River

Hoh Creek-Hoh River

South Fork Hoh River

Mount Tom Creek-Hoh River

Maple Creek-Hoh River

Hell Roaring Creek-Hoh River

Nolan Creek-Hoh River

HUC12

Area (SqKm)

171001010701

120.59

171001010702

79.78

171001010703

139.04

171001010704

125.78

171001010705

67.2

171001010706

123.7

171001010707

115.38

Open water features, including the Hoh River mainstem, creeks, ponds, and small lakes, represent

2,469 acres (1.29% of the watershed) according to GIS analysis. The extensive stream network

totals 1,299 miles of mapped channels, creating an intricate drainage system that connects upland

areas to the Paciﬁc Ocean. This network includes the Hoh River mainstem extending 56 miles

from its glacial origins to the ocean, plus numerous tributaries that support critical salmonid

spawning and rearing habitat.

Historical Monitoring Program

The Hoh Tribe has conducted systematic water quality monitoring throughout the Hoh River Basin

since the early 1990s, establishing the longest continuous water quality datasets for the watershed.

This multi-decade monitoring effort provides critical baseline data for assessing long-term trends,

documenting persistent impairments, and evaluating watershed responses to land management

changes and climatic variations.

The Hoh Water Quality Program (HWQP) began comprehensive monitoring in 1991 with

deployment of continuous temperature loggers in the Hoh River mainstem and major tributaries

(Hoh Tribe FY25 CWA 106 Report, 2025). This initial focus on temperature responded to observed

impacts from timber harvest activities, which had intensiﬁed throughout the watershed during the

1980s timber boom. Temperature was selected as the primary indicator based on its critical

importance to salmonid survival and its responsiveness to riparian canopy removal. The strategic

placement of loggers in creeks providing year-round ﬂow, major tributaries, and the Hoh River

mainstem at multiple points established the foundation for understanding thermal dynamics across

the watershed's diverse habitats.

The Tribe has maintained continuous temperature monitoring at 22 year-round stations and up to

28 additional summer stations within the Hoh River Watershed monitoring network (Hoh Tribe

FY25 CWA 106 Report, 2025). Strategic placement of loggers captures longitudinal temperature

proﬁles through multiple mainstem sites documenting temperatures from headwaters to mouth,

tributary contributions via stations above and below major conﬂuences to quantify thermal inputs,

thermal refugia, and hyporheic exchange zones identiﬁed through FLIR surveys, and land use

gradients through paired sites above and below harvest units and road crossings.

The program underwent signiﬁcant expansion in 2000-2001 with a basin-wide Forward Looking

Infra-Red (FLIR) study conducted through ground-truth and helicopter surveys (Aerial Surveys in

the Hoh River Basin, 2001). FLIR technology detects thermal radiation emitted from water

surfaces, identifying cool water refugia critical for salmonid survival during summer months. This

thermal imaging assessment mapped groundwater inputs, documented thermal pollution sources,

and established priority monitoring locations that continue to be sampled today. The FLIR analysis

revealed previously unknown cold-water springs, identiﬁed reaches where riparian loss created

thermal loading.

Monthly instantaneous monitoring for multiple parameters commenced in 2005, adding dissolved

oxygen, pH, and turbidity measurements to the temperature monitoring network to 20 new or

existing sites in 2021 (Hoh Tribe FY25 CWA 106 Report, 2025). This expansion coincided with

increasing recognition that temperature alone could not fully characterize water quality impacts

from land use activities. The multi-parameter approach enabled detection of cumulative effects

from forest practices, road networks, and development, revealing complex interactions between

thermal pollution, oxygen depletion, and pH depression that single-parameter monitoring would

miss.

The channel of the Hoh River is highly complex and dynamic, with large migration zones. As

steep, glacially-carved valley walls near its headwaters transition to a wide alluvial floodplain

downstream, glacial sediments in the river are distributed across wide braided channels. The

watershed is especially rainy, with the annual mean precipitation in the watershed ranging between

94 and 125 inches (England, 2003). As a result, major flood events are frequent, especially in

winter months. During floods, the Hoh River often avulses into old, abandoned channels or carves

new ones into low terraces and gravel bars. According to the United States Geological Survey

(USGS) gauging station on the Hoh River at Highway 101, peak runoff occurs in the winter from

October to March due to large rainfall events, while low flow is recorded in the summer. The

maximum discharge recorded since 1960 was 62,100 cfs (gage height = 20.2 ft) on October 17,

2003; minimum discharge recorded since 1960 was 196 cfs (gage height = 1.89 ft) on September

21, 2024, (U.S. Geological Survey, 2025).

Fish distribution data from the Washington Department of Fish and Wildlife conﬁrms the

watershed supports populations of chinook (Oncorhynchus tshawytscha), coho salmon

(Oncorhynchus kisutch), steelhead (O. mykiss), coastal cutthroat trout (O. clarkii), and bull trout

(Salvelinus conﬂuentus). The presence of these sensitive species throughout the stream network

underscores the importance of maintaining water quality across all land cover types.

As most sites monitored by the Tribe are not located on Tribal Reservation, trust, or fee lands, the

Hoh Tribe applies Washington State's water quality standards (Chapter 173-201A WAC) to assess

attainment of designated uses within the Hoh Watershed. These criteria establish numeric standards

for protecting aquatic life uses, with particular emphasis on salmonid habitat given the watershed's

critical importance for salmon and steelhead populations.

Figure 5. Water quality monitoring sites in the Hoh River Watershed. Site numbers correspond to those found in Table 4.

Table 4. List of monitoring sites conducted by the Hoh Tribe’s water quality monitoring program and their frequency and parameters.

Site Name

Map #

Temp.

Alder, Lower

Alder, Middle

Alder, Upper

Anderson, Lower

Anderson, Upper

Braden, Lower

Turb.

Flow

Benthic macroin.

M, C

M, SE

124.229225

47.829815

124.226756

47.848982

124.241098

47.771694

124.323045

47.781444

124.333260

47.739340

124.349698

47.731540

124.324708

47.817024

124.063933

Canyon downstream of Upper Hoh Road

M, SE

47.812813

124.070669

Canyon upstream of Upper Hoh Road

M, SE

47.813726

124.070907

Chalaat, Lower

M, C

47.744523

124.423781

47.737172

124.414742

47.781977

124.293126

47.814196

124.024150

47.812624

124.098379

47.802086

124.039139

Elk, Lower

47.809659

124.212923

Elk, Middle

47.798611

124.196944

47.798958

124.172857

47.734321

124.383816

Chalaat, Upper

Cottonwood

Crippen Springs

East Pole

E. F. Iron Maiden

Elk, Upper

Fletcher

Hell Roaring

Hoh above Anderson

Hoh above Barlows

Hoh above Campground

M, SE

M, C

47.815885

M, C

Canyon Springs

M, C

Longitude (W)

Braden, Upper

M, SE

Latitude (N)

M, SE

M, C

47.840109

124.262493

47.772739

124.314575

47.748662

124.388057

47.856069

123.929961

47.821942

124.197176

47.820204

124.018508

M, C

Hoh above Willoughby

Hoh at ONP Boundary

M, SE

Table 4 (cont.): List of monitoring sites conducted by the Hoh Tribe’s water quality monitoring program and their frequency and parameter.

Site Name

Map #

Temp.

Hoh Creek

Hoh Oxbow

Jackson

Line

Hoot

Lost

Maple, Lower

Maple, Upper

McQuarry-Fisher

Mount Tom

N.F. Winfield

Turb.

Latitude (N)

Longitude (W)

47.879339

123.754112

47.812511

124.250506

47.790253

123.963615

47.855163

123.925163

47.791398

123.970043

47.781337

124.269993

47.803377

124.089971

47.770946

124.100010

47.799704

123.988497

47.866800

123.887510

47.781535

124.196996

M, SE

Flow

Benthic macroin.

Nolan, Lower

M, C

47.751175

124.324632

Nolan, Middle

47.744451

124.281750

47.742364

124.240451

47.804241

124.079039

47.798555

124.079222

47.779911

124.079742

47.770711

124.291886

Nolan, Upper

Owl, Lower

Owl, Middle

Owl, Upper

Pins

S.F. Hoh

S.F. Hoh at Campground

M, C

Rock

M, SE

M, C

M, SE

47.817483

124.138163

M, SE

47.806054

123.996233

47.807991

123.998023

47.765486

124.347220

Snider

47.847710

123.971624

Snider at Upper Hoh Road

47.844104

123.966624

47.797040

123.983418

Taft

47.860354

123.946815

Taft at Upper Hoh Road

47.860084

123.940811

Six Mile

Split

M, SE

Table 4 (cont.): List of monitoring sites conducted by the Hoh Tribe’s water quality monitoring program and their frequency and parameters.

Site Name

Tower

Twin, Lower

Twin, Upper

West Pole

Map #

Temp.

Turb.

M, C

M, SE

M, C

M, SE

Flow

Latitude (N)

Longitude (W)

47.817857

124.119303

47.832780

123.990266

47.835370

124.002435

47.813405

124.105330

47.801612

124.040714

47.822138

124.198055

47.798882

124.229283

47.771304

124.198823

M, C

M, SE

Willoughby

M, C

M, SE

Winfield, Lower

M, CY

M, SE

W.F. Iron Maiden

Winfield, Upper

Benthic macroin.

Table 5. List of monitored rivers and creeks in the Hoh River Watershed as outlined in the Hoh River

monitoring program. Sites highlighted green represent creeks within Hoh Tribal Trust and Fees lands.

Sites with * have additional salmonid spawning protections.

Site

Alder, Lower; Middle; Upper

Anderson, Lower

Anderson, Upper

Braden, Lower; Upper

Canyon Springs

Canyon upstream & downstream

of Upper Hoh Rd

Chalaat, Lower; Upper

Cottonwood

Crippen Springs

East Pole

E. F. Iron Maiden

Elk, Lower; Middle; Upper

Fletcher

Hell Roaring

Hoh above Anderson

Hoh above Barlows

Hoh above Campground

Hoh above Willoughby

Hoh at ONP Boundary

Hoh Oxbow

Hoot

Jackson

Line

Lost

Maple, Lower

Maple, Upper

McQuarry-Fisher

Mount Tom

N.F. Winfield

Nolan, Lower

Nolan, Middle

Nolan, Upper

Owl, Lower & Middle

Owl, Upper

Pins

Rock

S.F Hoh

Six Mile

Snider & Snider at Upper Hoh Rd

Split

Taft

Taft at Upper Hoh Rd

Tower

Twin, Lower

Twin, Upper

West Pole

W.F. Iron Maiden

Water

Type

Creek

Waterbody

length (mi)

3.57

2.99

0.47

5.51

0.51

2.91

Creek

River

Creek

River

Creek

1.22

0.04

unknown

0.42

1.04

2.15

0.70

1.38

1.11

1.68

1.05

0.85

1.74

1.45

1.51

4.36

1.96

0.97

1.82

1.55

1.25

2.43

0.82

2.73

1.65

2.86

0.83

2.58

2.73

2.00

1.32

1.97

1.84

0.36

1.72

0.15

0.44

0.53

2.79

0.26

0.66

Usage Information

Core Summer Salmonid Habitat*

Core Summer Salmonid Habitat

Core Summer Salmonid Habitat*

Core Summer Salmonid Habitat

Core Summer Salmonid Habitat*

Char Spawning and Rearing

Core Summer Salmonid Habitat*

Char Spawning and Rearing

Core Summer Salmonid Habitat*

Char Spawning and Rearing

Core Summer Salmonid Habitat

Char Spawning and Rearing

Core Summer Salmonid Habitat

Core Summer Salmonid Habitat*

Core Summer Salmonid Habitat

Core Summer Salmonid Habitat*

Core Summer Salmonid Habitat

Char Spawning and Rearing

Core Summer Salmonid Habitat

Char Spawning and Rearing

Core Summer Salmonid Habitat*

Char Spawning and Rearing

Core Summer Salmonid Habitat

Site

Willoughby

Winfield, Lower

Winfield, Upper

Water

Type

Creek

Waterbody

length (mi)

0.44

3.59

1.16

Usage Information

Core Summer Salmonid Habitat*

Wetlands and Aquatic Features

Wetland complexes throughout the watershed provide critical water quality functions. GIS analysis

identiﬁes 8,056 acres (4.21% of the total area) of wetlands, including 7,425 acres of woody

wetlands and 631 acres of emergent herbaceous wetlands (Figure 5). The National Wetlands

Inventory (NWI) database maintained by US Fish and Wildlife Service (USFWS) likely

underrepresents actual wetland extent due to the challenges of mapping wetlands beneath dense

forest canopy. Recent LiDAR research by Stewart et al. (2024) reveals that traditional satellite

mapping signiﬁcantly underestimates forest complexity within the watershed. Their discovery of

extensive "cryptic" wetlands hidden beneath the forest canopy indicates that forested areas provide

greater ecological functions than previously understood. Using Wetland Intrinsic Potential (WIP)

mapping tools, researchers found that including these hidden forested wetlands increases

watershed carbon-storage capacity estimates by ﬁvefold, suggesting the watershed's forests play

an even more critical role in landscape regulation and water quality protection than recognized in

earlier assessments.

The Tribe is actively developing a wetland inventory in cooperation with University of Washington

using a new wetland mapping tool by Monika Moskal’s lab. The WIP Tool creates a map of

probabilities of wetland location. With traditional methods of mapping analysis, it is difficult to

locate wetlands that exist under forest canopies. The WIP is not meant to be regulatory and is not

a replacement for, but a supplement to, the NWI, which will be beneficial for addressing gaps in

the watersheds nonpoint pollutant sources.

Ground Water Standards

Washington's groundwater quality standards under Chapter 173-200 WAC establish protection

criteria for subsurface waters that inﬂuence surface water quality through baseﬂow contributions.

While groundwater provides baseﬂow critical for maintaining summer stream temperatures and

dissolved oxygen, the interaction between groundwater and surface water in the Hoh watershed

remains poorly characterized. Groundwater quality monitoring is not currently conducted as part

of the Tribe's water quality program, though individual domestic wells exist within the reservation

boundaries.

The HWQP was temporarily suspended from February 2020 through June 2021 due to COVID-19

pandemic restrictions (Hoh Tribe FY23 CWA 106 Report). This unprecedented disruption created

a data gap during critical seasonal transitions but also demonstrated the program's resilience and

importance to tribal resource management. Monitoring resumed in July 2021 with addition of

dissolved oxygen saturation and speciﬁc conductivity parameters, providing more complete water

quality characterization. Speciﬁc conductivity serves as a surrogate for total dissolved solids,

indicating groundwater inputs, road salt applications, or other ionic pollution sources, while DO

saturation helps distinguish temperature-driven oxygen loss from biochemical oxygen demand.

Pollutants

The Tribe’s water quality monitoring program, cultural accounts, and historical landscape records

provide insight into existing and potential pollutants. The greatest threats to the watershed are

temperature, dissolved oxygen, pH, and sedimentation delivery. Pollutants stem from various

categories of sources like forestry, hydromodification, roads, invasives, atmospheric deposition,

and gravel mining.

Table 6. Existing or potential pollutants throughout the Hoh River Watershed.

Pollutants

Temperature

Dissolved Oxygen

Stormwater Runoff

Turbidity/Suspended Solids

Toxic Chemicals

Undersized Culverts

Invasives

Large woody debris

RESULTS

The Hoh River and its tributaries are often described as a relatively pristine, intact habitat for

salmonids and other native fish species. Nevertheless, our monitoring efforts point to persistent

and long-standing forms of water quality impairments in the Hoh River and tributaries. Warm

water temperatures in the summer are the most apparent threat to salmon and char. From long-term

monitoring efforts by the Hoh Tribe and others, it has been shown that warm waters which threaten

salmonids and char have been present in the Hoh River and many tributaries for more than a

decade, with additional tributaries being listed since then. From our efforts, we identified that more

than half of the waterways that we monitor in the HRW were not achieving tribal goals or the State

of Washington’s water quality standards.

In the face of environmental fluctuations and impending loss of the glaciers that feed the

watershed, existing cold water refugia will likely be further diminished in the future. Moreover,

we have found low dissolved oxygen concentrations in the Hoh River and some creeks, which may

be linked to warm temperatures and/or dissolved organic carbons in some sites. Finally, our

monitoring program has identified tributaries of the Hoh River that have very low pH, although it

is yet to be determined if this is from anthropogenic influences or natural conditions. Given the

Hoh Tribe’s dependence on salmon and steelhead, the identified water quality issues are of tribal

concern. Efforts should be made to protect waterways that we identified as fully supporting

designated aquatic life uses and restore those with poor water quality.

The Hoh Tribe’s water quality monitoring program is responsible for assessing approximately 60

sites each year for a specific set of parameters including:

•

Temperature

Turbidity

Specific conductivity

Flow

Benthic macroinvertebrates

The frequency of monitoring these parameters varies by site but includes continuous and discrete

records (Table 4). Because the Tribe’s monitoring network is so expansive, data shows that sites

are located and exposed to various pollutants covering the watershed lands. The Tribe assesses

water quality data on a yearly basis, which is useful for establishing most recent water quality

conditions. However, the water quality program hasn’t yet established baselines or long term

parameter “normals”. The following section provides insight into 2025’s monitoring results.

Although the program has not established numerical normals, the program tracks narrative

conclusions like creek impairments by year and pollutant.

Instantaneous monthly monitoring showed four creeks/rivers were impaired due to temperatures

outside of their respective criteria. The impaired sites included Lower Nolan, Lower Winfield, and

Middle Elk Creek, and the SF Hoh River. Nolan Creek claimed the highest average site

temperature, 10.92°C, and maximum temperature overall, 19.15°C (Hoh FY25 CWA 106

Assessment Report, 2025).

Continuous temperature monitoring in FY 2025 yielded twenty-one impairments throughout the

watershed. Impairments were observed at four sites within the Hoh River mainstem, twelve of the

Hoh River's tributaries, the SF Hoh River, and three of the SF Hoh River’s tributaries (Hoh FY25

CWA 106 Assessment Report, 2025). The Hoh River and nine tributaries did not fully support

core summer salmonid habitat based on our continuous temperature monitoring. Additionally, the

Hoh River, the SF Hoh River, and seven tributaries did not fully support char spawning and rearing

either.

Hoh River above Barlows had the highest monthly 7-DADM average temperature, 20.02°C, in

June; the maximum 7-DADM calculated for a single day, 22.01°C in August; and the maximum

temperature occurrence, 23.97°C in August. Upper Nolan Creek held the lowest monthly 7DADM average temperature. Middle Nolan Creek recorded the lowest daily 7-DADM

temperature, 2.02°C, and the lowest recorded temperature, 0.4°C, in February (Hoh FY25 CWA

106 Assessment Report, 2025).

Of the 48 sites monitored over the summer, 30 sites experienced their hottest monthly 7-DADM

average in August and 12 sites in July. This is likely due to warmer than usual temperatures in

August across the state. Temperatures recorded at Quillayute’s weather station were 2.0°F above

normal (Genuise, 2025).

Waters designated for general salmonid use showed extensive impairments affecting spawning and

rearing success. Fifteen tributaries consistently exceeded the 16°C criterion during summer

months, including Alder, Anderson, Elk, Line, Lost, McQuarry-Fisher, Mount Tom, Owl (lower),

Split, Snider, Tower, Twin, Willoughby, and Winﬁeld Creeks. Many of these streams have

remained on the 303(d) list since 1996, indicating chronic impairment persisting nearly three

decades.

Low pH in Lower Braden and Hell Roaring is longstanding. Monthly instantaneous pH

measurements have shown pH impairment since 2018 in Lower Braden Creek and since 2005 in

Hell Roaring Creek. HWQP historical instantaneous data from 2005-2025 shows pH impairments

at Lower Braden Creek for 16 out of 21 years, at Lower Chalaat Creek for 10 out of 20 years, at

Hell Roaring Creek for 21 years, and at Lower Nolan Creek for 6 out of 21 years. Historical

monthly data from Hell Roaring Creek dating back to 2005 indicates that the site hasn't recorded

a pH above 6.5 since 2018. Lower Chalaat Creek has had pH issues since 2020.

Three of the four sites with pH impairments also had accompanied DO impairments. Lower

Braden, Hell Roaring, and Lower Nolan Creek failed to maintain DO concentrations above 9.5

mg/L for less than the 5% of allowable exceedance days. Braden and Nolan Creek were below the

criterion from June to August and Hell Roaring in October 2024 and from June to September 2025

(no measurement in July). Hell Roaring led in lowest average DO concentration this year, 9.83

mg/L, and lowest single event occurrence, 7.74 mg/L. The maximum average DO concentration,

11.84 mg/L, occurred at Snider Creek. The maximum DO concentration, 12.9 mg/L, occurred at

Lower Willoughby Creek (Hoh FY25 CWA 106 Assessment Report).

Table 7. Historical DO and pH impairments at high-risk creeks.

Total Years Total Years

Impaired

Monitored

Chalaat Creek

Braden Creek

Hell Roaring Creek

Nolan Creek

Chalaat Creek

Braden Creek

Hell Roaring Creek

Nolan Creek

Analysis of HWQP historical instantaneous data (2007-2025)

points to persistent DO impairment in Lower Chalaat Creek for

16 of the past 19 years of monthly monitoring (Table 7). This

year marks the first year since 2022 that Chalaat Creek will not

be listed for DO impairment. Braden Creek DO impairment has

returned after three years without measured impairments (not

including continuous data). Similarly, Nolan Creek was not

listed for DO impairment based on monthly monitoring last

year; however, this year the DO issues have returned. Hell

Roaring continues to have persistent DO issues marking the 18th

out of 21st year of impairment based on historical monthly

monitoring data (Table 7). Furthermore, analysis of HWQP

instantaneous data measured from 2005 through 2025 shows

that water quality, whether pH or DO, has been impaired in Braden Creek and at Hell Roaring for

the past 21 years (Table 7).

According to the FY23 CWA 106 Report, Hell Roaring Creek contained disconnected pools from

June through September, while Braden Creek experienced complete cessation of ﬂow from July

through September, creating stagnant conditions where dissolved oxygen depletion becomes

inevitable regardless of temperature. This reality has occurred at various creeks in the past and is

not partial to just 2023. The FY25 CWA 106 Report also documented impairments in the Hoh

River at multiple sites exemplifying low oxygenation in larger channels where stagnation and

disconnection would not be an issue.

According to the U.S. Fish and Wildlife Service National Wetland Inventory, the sites with DO

impairments (Lower Braden Creek, Hell Roaring Creek, Hoh River above Anderson, and Lower

Nolan Creek) are located downstream of freshwater forested/shrub wetlands (U.S. Fish and

Wildlife Service, 2022). Data involving nearby wetland analysis would be useful to gather

baselines and a greater understanding of how these relationships cooperate with each other. We

continue to recognize, however, that elevated water temperatures could still be a cause of reduced

DO concentrations through decreased solubility.

The Hoh Tribe does not have benchmark goals for ambient turbidity, specific conductivity, or

instream flow because Washington State does not have aquatic life criteria for these water quality

parameters. Furthermore, setting criteria for ambient turbidity requires site-specific information

(i.e., baseline conditions for turbidity and conductivity, local geology and soils types) that is

currently not available for the Hoh River and its tributaries. However, baseline conditions can be

established by continuing to collect turbidity and conductivity data, which can then be used to set

tribal goals in the future.

Turbidity standards protect aquatic life from suspended sediment impacts including gill abrasion,

reduced feeding efficiency, and substrate embeddedness that eliminates spawning habitat.

Washington's criteria prohibit turbidity increases exceeding 5 NTU over background when

background is 50 NTU or less, or more than a 10% increase when background exceeds 50 NTU

during in-water work. These incremental standards recognize natural background variability while

preventing human-caused degradation that would impair designated uses. However, Washington

State does not have turbidity criteria for ambient conditions.

Field observations at Canyon Creek documented the physical sources of the watershed's most

severe turbidity impairment, with steep banks requiring riprap and netting installations from

ongoing instability due to clay deposits. The direct discharge of stormwater from Upper Hoh Road

observed ﬂowing quickly into the creek without any treatment or velocity dissipation provides a

chronic clay sedimentation to be activated during every precipitation event. Similarly, at the Oil

City Road unnamed stream crossing, ﬁeld crews documented failed erosion control infrastructure

where old riprap had fallen into the channel, creating both a sediment source and partial barrier to

ﬂow.

Integration of USGS ﬂow data with water quality monitoring reveals important relationships where

temperature exceedances correlate with low ﬂow periods, DO sags coincide with reduced

velocities and reaeration, turbidity spikes follow rain-on-snow events, and seasonal patterns show

earlier spring runoff and extended summer baseﬂow periods. The August 2023 base ﬂows

averaging 40-60% below long-term means demonstrate an accelerating trend toward summer ﬂow

depletion that exacerbates all other water quality impairments.

Benthic macroinvertebrate sampling has occurred at Anderson, Elk, Nolan, Owl, and Winfield

Creeks during summer low flow conditions since 2021. All creeks monitored have held excellent

to excellent/good standards according to the Benthic Index of Biotic Integrity scoring system.

Although water quality impairments are present in these creeks, macroinvertebrate species still

show up in diverse populations compared to other Western Washington areas.

Table 8. Monitoring sites in rivers and creeks of the Hoh River Watershed with impaired water quality

from FY 2021-2025 that did not fully support designated uses.

Monitoring Site

Alder, Lower

Anderson, Lower

Braden, Lower

Chalaat, Lower

Chalaat, Upper

Elk, Middle

Elk, Upper

Hell Roaring

Hoh River above

Anderson

Hoh River above

Barlows

Hoh River above

Campground

Hoh River above

Willoughby

Hoh at ONP

Boundary

Hoh Creek

Hoot

Jackson

Line

Lost

Maple, Lower

McQuarry-Fisher

Mount Tom

N.F. Winfield

FY 2021

Temp

DO, pH

None

Temp

None

Temp

DO, pH, Temp

FY 2022

Temp

None

DO, pH

Temp

None

DO, pH

DO,

Temp

FY 2023

Temp

DO, pH

Temp

None

DO, pH

FY 2024

Temp

None

DO, pH

Temp

None

DO, pH

FY 2025

Not monitored

None

DO, pH

Temp

DO, pH

DO, Temp

Temp

DO, Temp

Temp

None

Temp

None

Temp

Temp, DO

Not monitored

Temp

None

Temp

Not monitored

Temp

None

Temp

None

DO, pH,

Temp

None

Temp

None

Not monitored

Temp

None

Temp

Not monitored

Temp

None

Temp

None

Not monitored

None

Temp

None

Temp

None

Nolan, Lower

DO, Temp

DO, pH, Temp

Nolan, Middle

Owl, Lower

S.F. Hoh

Snider

Split

Taft

Tower

Twin, Upper

Willoughby

Winfield, Lower

Winfield, Upper

Temp

None

Temp

None

Temp

None

Temp

None

Temp

DO, Temp

Since expanding and maintaining our monitoring efforts in 2021, the Hoh Tribe’s water quality

data has determined that 34 locations have shown impairment for at least one parameter (Table 8).

Removing redundancies like “upper”, “lower” creeks and Hoh River sites at different mile markers

still leaves 26 total creeks/rivers with impairments. This list encompasses the Tribe’s assessment

of all monitoring including continuous and discrete temperature, pH, DO data.

The Wahington Department of Ecology recently updated their listings of the impaired waterways

(303(d)) in releasing their 2022 Assessment cycle data. This cycle added 8 new creeks to the list

of impairments and now includes impairments for parameters like dissolved oxygen and pH as

compared to the 2018 data cycle (Table 9).

Table 9. Impaired waterbodies within the HRW according to the Washington Department of Ecology’s

2022 Waterbody Assessment Cycle.

WATERBODY

ALDER CREEK

PARAMETER

Temperature

ALDER CREEK

Temperature

ANDERSON

CREEK

BRADEN

CREEK

ELK CREEK

Temperature

ELK CREEK

Temperature

FISHER CREEK

(MCQUARRY

CREEK)

HOH RIVER

Temperature

HOH RIVER

Temperature

HOH RIVER

Dissolved

Oxygen

Temperature

HOH RIVER

Temperature

HOH RIVER

Temperature

HOH RIVER

Temperature

HOH RIVER

Temperature

HOOT CREEK

Temperature

JACKSON

CREEK

LINE CREEK

Temperature

LOST CREEK

Temperature

MAPLE CREEK

Temperature

Dissolved

Oxygen

Temperature

DESIGNATED USE

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Char Spawning and

Rearing

ASSESSMENT UNIT ID

17100101000708_001_001

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

17100101013703_001_001

17100101000701_001_002

17100101012795_001_001

17100101000359_001_001

17100101023220_001_002

17100101023224_001_001

17100101013878_001_001

17100101000044_001_001

17100101000033_001_001

17100101013742_001_001

17100101023769_001_001

17100101000033_001_001

17100101000091_001_001

17100101000077_001_001

17100101000770_001_001

17100101000380_002_002

17100101046753_001_001

17100101013209_001_001

17100101000383_001_001

Table 9 (cont.): Impaired waterbodies within the HRW according to the Washington Department of

Ecology’s 2022 Waterbody Assessment Cycle.

WATERBODY

NOLAN CREEK

PARAMETER

Temperature

DESIGNATED USE

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Char Spawning and

Rearing

Aquatic Life - Core Summer Salmonid

Habitat

ASSESSMENT UNIT ID

17100101000766_001_001

NOLAN CREEK

Dissolved

Oxygen

Temperature

OWL CREEK

Temperature

POLE CREEK

Temperature

SNIDER CREEK

Temperature

SOUTH FORK

HOH RIVER

SPLIT CREEK

Temperature

TOWER CREEK

Temperature

TWIN CREEK

Temperature

UNNAMED

CREEK (TRIB

TO EAST FORK

HELL

ROARING

CREEK)

UNNAMED

CREEK (TRIB

TO EAST FORK

HELL

ROARING

CREEK)

UNNAMED

CREEK (TRIB

TO WINFIELD

CREEK)

WILLOUGHBY

CREEK

WINFIELD

CREEK

WINFIELD

CREEK

Dissolved

Oxygen

Aquatic Life - Core Summer Salmonid

Habitat

17100101012968_001_001

Temperature

Aquatic Life - Core Summer Salmonid

Habitat

17100101000767_001_002

Temperature

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

Aquatic Life - Core Summer Salmonid

Habitat

17100101000699_001_001

Temperature

17100101000766_001_001

17100101000769_001_001

17100101000394_001_001

17100101000719_001_002

17100101000698_002_002

17100101013869_001_001

17100101020036_001_001

17100101000718_001_002

17100101000704_001_001

17100101012968_001_001

17100101000744_001_001

17100101000746_001_001

Nonpoint Source Assessment

Nonpoint Source categories were chosen based on factors affecting our waterways. Temperature,

DO, pH, and turbidity were prioritized given our extensive data and cultural priorities.

Assessment ﬁndings derive from synthesis of five years of monitoring data (FY2021-2025), and

review of existing documentation. Seven major NPS categories were identiﬁed.

Forestry & Logging Roads

Forest management activities and associated road networks represent the most widespread

nonpoint source pollution category affecting water quality in the Hoh River Watershed. The

combination of timber harvest, road construction and maintenance, and log transport creates

multiple pathways for sediment delivery, thermal pollution, and hydrologic alteration. The spatial

distribution of these forestry impacts, which overlays active harvest areas and road networks with

documented water quality impairments.

Hydromodiﬁcation & Bank Erosion

Hydromodiﬁcation, the alteration of natural stream channels and ﬂoodplains, combines with

accelerated bank erosion to deliver substantial sediment loads while fundamentally disrupting

aquatic habitat. The Hoh River's dynamic channel migration, exacerbated by land use impacts,

creates both natural and anthropogenic sources of water quality degradation. Extensive erosion

control infrastructure exists throughout the watershed, including massive concrete dolosse

structures placed between the river and Upper Hoh Road, indicating the severity of bank erosion

challenges.

Invasive Species

Extensive invasive species have been identified by various organizations throughout Washington

like Washington Native Plant Society, Washington State Department of Agriculture (WSDA),

Washington Department of Natural Resources (DNR), 10K Years Institute (10K), and more. Their

presence contributes to species monoculture, limited nutrient and soil profiles, and replacement of

stabilizing vegetation. Mapping of invasives in the Hoh River Watershed is extensive because of

publicly available noxious weed reporting. However, mapping fails to represent noxious weeds

within Olympic National Park and at higher elevations (Figure 6).

Roads, Highways, and Bridges

Roads, highways, bridges, and associated infrastructure create concentrated sources of nonpoint

source pollution through increased impervious surfaces, altered drainage patterns, and introduction

of vehicle pollutants. While the Hoh watershed remains predominantly rural, extensive

transportation corridors generate measurable water quality impacts. Near development, there are

multiple pathways for untreated stormwater to reach surface waters, with no stormwater treatment

infrastructure observed at major discharge points.

Figure 6. Noxious Weed Detections throughout the HRW with monitoring sites waterways labeled.

Natural Resource Extraction

Historical gravel extraction has created disturbed areas throughout the watershed vulnerable to

erosion and potentially vehicle-related emissions. Unreclaimed pits contribute pollutants through

sediment mobilization at 100-1,000 tons/acre/year from exposed surfaces, hydrocarbon

contamination at 100-1,000 mg/kg TPH from equipment operations, pH impacts from exposed

minerals creating pH 4-5 or 9-11 extremes, temperature effects with shallow ponds reaching 2535°C in summer, and heavy metals including iron at 1,000-10,000 mg/L in acidic conditions

(Newton and Drenten, 2015). There are currently three gravel mining operations active within the

watershed, the Seton Construction Canyon Creek Quarry located by Canyon Creek, Winfield

Surface Mine DNR located near Elk and Winfield Creeks, and the St. Regis Gravel Pit located

near an unnamed creek and wetland.

Atmospheric Deposition

Chronic deposition from vehicle traffic creates distributed contamination along Highway 101 and

forest roads. Annual deposition rates include 0.1-1.0 kg/hectare/year of PAHs, 10- 100

g/hectare/year of heavy metals including copper, zinc, and lead, 1-10 kg/hectare/year of petroleum

hydrocarbons, and 0.01-0.1 kg/hectare/year of platinum group elements from catalytic converters

(Hwang et al., 2016). The Highway 101 bridge crossing, with its documented lack of stormwater

treatment, delivers these contaminants directly to the Hoh River.

Data Gaps in Historical Record

Temporal gaps include limited winter monitoring due to access and safety constraints, the COVID19 suspension from February 2020 through June 2021, and intermittent equipment failures during

extreme events. These gaps, while unavoidable, create uncertainty in annual assessments and may

underestimate impairment frequency.

Spatial gaps affect headwater areas above 3,000 feet elevation where snow and access limit

monitoring, non-ﬁsh bearing tributaries that receive minimal monitoring despite contributing ﬂow

and pollutants, and wetland systems that require different sampling protocols than stream

monitoring. Private industrial forest lands often restrict access, creating gaps in understanding of

active harvest impacts.

Results Assessment

The consistency of degradation trends across parameters, sites, and years indicates that current

management approaches have failed to arrest, much less reverse, water quality decline. Despite

three decades of forest practice rules, salmon recovery efforts, and restoration investments, no

monitored parameter shows statistically signiﬁcant improvement. Several sites show accelerating

degradation, suggesting threshold effects where initial impacts trigger cascading ecosystem

changes.

The persistence of temperature impairments since 1996 despite riparian replanting indicates that

passive recovery through vegetation regrowth cannot overcome landscape-scale changes and

landscape forcing. The emergence of new impairments in previously unaffected waters suggests

degradation is spreading rather than contracting. Most concerning is that reference sites within

Olympic National Park also show warming trends, eliminating upstream sources for recolonization

even if downstream conditions improved.

Recovery planning must acknowledge these trajectories and design interventions scaled to

observed degradation rates. The ﬁeld observations of extreme conditions like streams drying

completely, pH below 5.0, temperatures exceeding 20°C indicate some waters have crossed deadly

thresholds where restoration may take years to show promise.

DISCUSSION

While many waterways have long-term water quality degradation, some stream reaches maintain

conditions meeting water quality standards or possess exceptional ecological and cultural

signiﬁcance warranting protection from future degradation. These waters, though increasingly rare

within the watershed, provide critical refugia for sensitive species, serve as reference conditions

demonstrating potential recovery, and support treaty-reserved resources fundamental to Hoh Tribal

identity and subsistence. Protection of these high-quality waters represents an equally important

management priority as restoration of impaired reaches, particularly given projected landscape

change impacts that will intensify pressure on remaining functional habitat.

Temperature Impairments

The geographic distribution of water quality impairments reveals clear patterns corresponding to

land use intensity and channel position within the watershed. Temperature impairments

concentrate in tributaries draining actively managed forestlands, particularly those accessed by the

Hoh Mainline Road where DNR and private timber company lands undergo regular harvest

rotation. These streams—including Owl, Winﬁeld, Elk, and Maple Creeks—show persistent

temperature violations dating to 1996, indicating that current forest practices rules have not

successfully restored thermal regimes.

Water temperature was the primary water quality parameter of concern. Twenty-two sites, four

within the Hoh River mainstem, fourteen of its tributaries, the SF Hoh River mainstem, and three

of its tributaries were impaired due to warm temperatures. In total, we found that 35.8 river miles,

or 47% of the total length monitored for water temperature, had temperatures that exceeded

criteria. In comparison, FY 2024 temperature impairments spanned 46.1 river miles or 47.8% of

total waters assessed for temperature (Hoh Tribe FY2025 Water Quality Assessment, 2025). Of

the total 76 river miles we assessed in the watershed in FY 2025, 43.8 river miles (57.68%) were

impaired because at least one water quality parameter did not meet water quality standards criteria.

This is an increase in impairments from last year's total extent of waters assessment.

Reports have linked canopy cover loss from logging with elevated water temperatures in Hoh

River tributaries. In the 1990s, large-scale timber harvests in the HRW were associated with

significant changes in water temperature. Hatten (1992) showed that daily maximum water

temperatures were two to three times greater for Hoh River tributaries in logged sub-basins (> 65%

timber removed) than in forested streams. Daily maximum temperatures also exceeded

Washington state’s water quality standards, creating unsuitable warm environments for salmon.

Additionally, the study found that logged streams had more variable day-to-day and diurnal water

temperatures than those in unharvested areas. Fluctuating temperatures hinder salmon’s ability to

adjust to warming temperatures (Coutant, 1977; Hokanson et al., 1977; Torgersen et al., 1999).

Hatten & Conrad (1995), Murray et al. (2000), and Pollock et al. (2004) supported Hatten’s (1992)

findings. In all three studies, daily average and/or maximum temperatures were significantly

greater in logged Hoh River tributaries.

Following the adoption of Washington State’s Forest Practices Habitat Conservation Plan in

2006, protections for aquatic species were greatly improved on state forest lands. The goal of the

plan is to protect endangered aquatic and riparian species under the Endangered Species Act. Prior

to the adoption of the plan, forests could be logged up to creek banks. Leaving a forested riparian

buffer along fish-bearing streams became a requirement when the plan was adopted. Although

logging practices are more protective of riparian zones and waterways now than they were in the

1990s, many waterways in the HRW have legacy effects from historical logging practices. The

Hoh River and many of its tributaries downstream of the South Fork Hoh River (ie., outside of

ONP) lack sufficient canopy cover and instream large wood debris because old-growth riparian

zones have yet to re-established (Smith, 2000). Loss of old-growth trees along waterways results

in widening of the channel and a loss of cold-water pools, which contribute to warm water. Of the

26 sites with impairments, 18 were located on designated forest land owned by a private entity (9

sites) or the State of Washington (9 sites).

Forest management and road networks fundamentally alter watershed hydrology. Road networks

intercept subsurface ﬂow, concentrate surface runoff, and extend the drainage network, leading to

ﬂashier hydrographs with higher peak ﬂows and reduced base ﬂows (Montgomery, 1994; Wemple

et al., 1996). These alterations manifest as increased peak ﬂows during storms, with 10-30%

increases documented in similar Paciﬁc Northwest watersheds. Runoff response times decrease by

50-70% in heavily roaded watersheds, concentrating ﬂow in destructive pulses. Conversely,

summer base ﬂows decline by 20-50% as intercepted subsurface ﬂow and reduced inﬁltration

diminish groundwater recharge.

Field observations of log jams at Winﬁeld Creek and debris accumulations at Nolan Creek

following ﬂood events demonstrate how altered hydrology interacts with woody debris to create

complex channel blockages that exacerbate both ﬂooding and low-ﬂow conditions.

Dissolved Oxygen Patterns

Dissolved oxygen and pH impairments cluster in lower gradient reaches where reduced velocity,

accumulated organic matter, and extended residence time create conditions for biochemical

oxygen depletion and acid accumulation. The severe impairments in Hell Roaring and Lower

Braden Creeks occur where extensive upstream disturbance combines with channel modiﬁcations

that concentrate pollutants.

Lower Chalaat Creek has shown chronic DO impairment throughout the monitoring period, failing

to meet the 9.5 mg/L criterion in 19 years (Table 7). This persistent impairment suggests complex

interactions between biochemical oxygen demand from organic inputs, reduced reaeration due to

low gradient and velocity, potential groundwater inputs with naturally low DO, and cumulative

effects from upstream land uses. The consistency of this impairment across diverse weather

patterns indicates systemic rather than episodic causation.

Low dissolved oxygen concentrations in the Hoh River and Lower Nolan Creek are potentially

produced by warm water temperatures. Dissolved oxygen becomes less soluble in warmer water,

resulting in a loss of DO from the waterway. In addition to low DO concentrations, we measured

warm water temperatures that exceeded the applicable designated uses criterion in both Lower

Nolan Creek and Hoh River above Anderson, Barlows, ONP, and Willoughby.

Prior to 2024, we hypothesized that Lower Braden, Lower Chalaat, and Hell Roaring Creek DO

complications were influenced by nutrient pollution since these creeks did not have paired

temperature impairments. After receiving results from our yearlong assessment of nutrients

derived from nitrogen and phosphorus in FY 2024, we did not see relationships that would indicate

there was eutrophication occurring.

The next alternative reasoning we addressed was dissolved organic carbon influences originating

from nearby wetlands. Freshwater wetlands are known for having high dissolved organic carbon

concentrations which promote aerobic respiration, thereby reducing DO concentrations. According

to the U.S. Fish and Wildlife Service National Wetland Inventory, the sites with DO impairments

(Lower Braden Creek, Hell Roaring Creek, Hoh River above Anderson, and Lower Nolan Creek)

are located downstream of freshwater forested/shrub wetlands (U.S. Fish and Wildlife Service,

2022). Our 2024 DOC analysis of all creeks suggested an inverse relationship between dissolved

organic carbon concentrations and dissolved oxygen concentrations (R2 = 0.62 p = <0.001)

(Hernandez, 2025). This relationship corroborates our hypothesis that DOC from nearby wetlands

is affecting DO concentrations. More data involving nearby wetland analysis would be useful to

gather baselines and a greater understanding of how these relationships cooperate with each other.

We continue to recognize, however, that elevated water temperatures could still be a cause of

reduced DO concentrations through decreased solubility.

pH Depression

Hell Roaring Creek has exhibited consistently acidic conditions since monitoring began, with pH

values frequently below 5.5 (Hoh Tribe FY25 CWA 106 Report). Lower Braden Creek shows

similar chronic pH depression. These patterns reﬂect both natural factors including organic acids

from wetland drainage and coniferous forest leachates high in fulvic and humic acids, and

anthropogenic inﬂuences such as potential acid deposition from atmospheric sources and altered

hydrology concentrating natural acids.

First, cedar spaults, or waste cedar pieces left over from timber harvesting, may be leaching watersoluble tannins, which are natural acids, into the creeks. When cedar spaults are in the wetted

channel, the water can become acidified from the tannins. Cedar spaults are pervasive in certain

parts of the watershed due to unrestricted logging during the 1970s and 1980s (Jill Silver, personal

communication). In 1999 and 2000, the Hoh Tribe’s Natural Resources Department removed cedar

spaults from Hoh River tributaries in order to improve fish passage and water quality (Silver, 2000;

Jill Silver, personal communication). During the project, Hell Roaring Creek was identified as one

of the Hoh River tributaries most impacted by cedar spaults. In some stretches of the creek, spaults

were so tightly packed that flow was reduced to a trickle. After five months of work, the crew

cleared spaults from ten miles of Hell Roaring Creek. Braden Creek was also identified as a

tributary in need of spault removal during the project. Despite the work completed in 1999 and

2000, cedar spaults likely remain within the riparian zone and channel of many creeks in the

watershed (Jill Silver, personal communication, Smith, 2000). During 2023, the water quality field

crew identified a log jam, which may have been created by cedar spaults, in Hell Roaring Creek

roughly 50 feet downstream of the sampling site (Kimberly Bray, Bernard Afterbuffalo, personnel

communication). Additionally, white foam in pools and backwater areas of the creek was noted,

which can result from high concentrations of tannins or organic matter (Kimberly Bray, Bernard

Afterbuffalo, personal communication). However, qualitative evidence of cedar spaults and tannin

leaching was not observed in Lower Braden, Lower Chalaat, or Lower Nolan Creeks in 2023.

Alternatively, we believed the acidic pH observed in these three creeks could be due to natural

decomposition processes. According to the U.S. Fish and Wildlife Service National Wetland

Inventory, Lower Braden, Lower Chalaat, and Hell Roaring Creeks are located downstream of

freshwater forested/shrub wetlands (U.S. Fish and Wildlife Service, 2023). Freshwater wetlands

can have extremely acidic water due to humic acids produced during the decomposition of organic

matter. When a creek becomes hydrologically connected to such freshwater wetlands, acidic water

from the wetland may enter the creek.

Sediment Sources

Forest management generates sediment through three primary mechanisms, each conﬁrmed

through ﬁeld observations:

Harvest Unit Erosion

Clearcut and regeneration harvest areas create exposed soil surfaces vulnerable to erosion.

Recently harvested areas ranging from fresh cuts to 15+ year-old regeneration stands along major

forest roads, including a recently harvested area adjacent to Anderson Creek and a 5-year-old

clearcut near Elk Creek. Steep slopes characteristic of many tributary watersheds amplify erosion

potential.

Surface erosion from harvest units delivers ﬁne sediment to streams through multiple pathways.

Concentrated runoff in skid trails and cable corridors creates chronic sediment sources. Sheet and

rill erosion on exposed mineral soil contributes background sediment loading. Gully formation

where drainage is concentrated can deliver pulses of coarse sediment. Delayed revegetation on

difficult sites extends the erosion window. Research in similar Olympic Peninsula watersheds

indicates sediment delivery rates from recently harvested areas can exceed 1,000 kg/ha/year in the

ﬁrst year post-harvest, declining to background rates of 10-50 kg/ha/year within 3-5 years as

vegetation establishes (Reid and Dunne, 1984; Swanson et al., 1989).

Forest Road Networks

Industrial forestlands in Western Washington typically maintain road densities ranging from 2.5 to

5.0 miles per square mile, well above the 2 miles per square mile threshold for properly functioning

watershed conditions established by NOAA Fisheries (1996). Watersheds with road densities

exceeding 3 miles per square mile are considered "not properly functioning," while sensitive

species like bull trout are often absent in watersheds with more than 1.5 miles of road per square

mile (Rieman et al., 2002).

The watershed's extensive forest road system creates chronic sediment sources. Road surface

erosion generates 50-300 tons/mile/year of ﬁne sediment from unpaved surfaces (Luce and Black,

1999). Cutslope and ﬁllslope failures at unstable locations deliver episodic sediment pulses. Ditch

line transport efficiently routes sediment-laden runoff directly to streams. Stream crossing failures

occur when undersized or poorly maintained culverts cause erosion during high ﬂows. Forest road

crossings, such as the single-lane wooden bridges at Maple Creek and Owl Creek Upper stations,

act as nonpoint sources of sediment when runoff enters streams during precipitation events.

Stormwater treatment infrastructure is lacking at critical discharge points throughout the

watershed. These deﬁciencies create direct pollutant pathways from transportation corridors to

receiving waters already stressed by other nonpoint sources.

The Highway 101 bridge crossing of the Hoh River consists of a narrow trestle bridge lacking any

stormwater control measures. Traffic-generated pollutants and road surface runoff ﬂow directly

into the river without treatment. This direct discharge delivers untreated runoff from the

watershed's busiest transportation corridor to waters already listed on the 303(d) list for

temperature.

Similar conditions exist at the Highway 101 crossing of Braden Creek, where the 20-25 foot wide

bridge lacks stormwater management infrastructure. Road runoff ﬂows directly off the bridge deck

and adjacent banks into the stream without treatment, entering the waterway approximately 40 feet

upstream of water quality monitoring equipment. This untreated discharge directly inﬂuences

documented water quality impairments at this long-term monitoring site.

The Oil City Road corridor presents additional concerns from unpaved surfaces generating chronic

sediment. At the unnamed stream crossing, ﬁeld observations documented substantial quantities

of dust and debris originating from the gravel road surface on both sides of the culvert, indicating

continuous ﬁne sediment delivery during both dry weather dust generation and wet weather erosion

events.

Data gathered from land use ownership, road maps, Washington Department of Fish and Wildlife

(WDFW) fish passage database, WSDA invasive species detection mapping, Jefferson County

permits, and staff technical expertise to determine river/creek specific impairment threats. Based

on spatial proximity, river/creek pollutants were linked to the available mapping and staff

ecological knowledge to assess their contributions. Severity of each waterbody was determined by

known documented impairments, historical data, and technical knowledge. Highest severity was

placed on creeks on the 303(d) list. Intermediate severity was placed on creeks that have not yet

been placed on the 303(d) list yet have years of historical data monitoring or technical knowledge.

Low priority sites have minimal category sources and land use violations but still have concerns

that need to be addressed. Summary of our assessment of individual creeks or rivers can be found

in Table 10.

Table 10. Summary of NPS category assessment for water quality monitoring sites.

Monitoring Site

Alder, Lower; Middle; Upper

Anderson, Lower

Anderson, Upper

Braden, Lower; Upper

Canyon Springs

Canyon upstream &

downstream of Upper Hoh Rd

Chalaat, Lower; Upper

Cottonwood

Crippen Springs

East Pole

E. F. Iron Maiden

Elk, Lower; Middle; Upper

Fletcher

Hell Roaring

Hoh above Anderson

Hoh above Barlows

Hoh above Campground

Hoh above Willoughby

Hoh at ONP Boundary

Hoh Oxbow

Hoot

Jackson

Line

Lost

Maple, Lower

Maple, Upper

McQuarry-Fisher

Mount Tom

N.F. Winfield

Nolan, Lower

Nolan, Middle

Nolan, Upper

Owl, Lower; Middle

Owl, Upper

Pins

Rock

S.F Hoh

Six Mile

Snider

Split

Taft

Taft at Upper Hoh Rd

Tower

Twin, Lower

Twin, Upper

West Pole

W.F. Iron Maiden

Willoughby

Winfield, Lower

Winfield, Upper

Waterbody

Impairment

length (mi)

3.57

Temp

2.99

Temp, Sediment

0.47

N/A

5.51

DO, pH

0.51

N/A

Severity Source Category

High

Medium

High

Low

Forestry, Roads, Hydromodification, Invasives

Forestry, Roads,

Forestry, Roads, Invasives

Forestry, Roads, Hydromodification, Invasives

High

Forestry, Hydromodification, Invasives, Extraction

2.91

Sediment

1.22

0.04

unknown

0.42

1.04

2.15

0.70

1.38

1.11

1.68

1.05

0.85

1.74

1.45

1.51

4.36

1.96

0.97

1.82

1.55

1.25

2.43

0.82

2.73

1.65

2.86

0.83

2.58

2.73

2.00

1.32

1.97

1.84

0.36

1.72

0.15

0.44

0.53

2.79

0.26

0.66

0.44

3.59

1.16

DO, pH, Sediment, Temp High

N/A

Medium

N/A

Low

Temp

High

N/A

Medium

DO, pH, Temp

High

DO, Temp, Sediment

High

DO, Temp, Sediment

High

Temp, Sediment

High

Temp, Sediment

High

Temp, DO, Sediment

High

N/A

High

Temp

High

Temp

High

Temp

High

Temp

High

Temp

High

Temp

High

Temp

High

Temp

High

Temp

High

DO, pH, Temp, sediment High

Temp

High

Temp

High

N/A

High

N/A

Low

N/A

Medium

Temp

High

N/A

Medium

Temp

High

Temp

High

N/A

Medium

Temp

High

N/A

Temp

High

N/A

Medium

N/A

Medium

Temp

High

Temp, Sediment

High

Temp, Sediment

High

Forestry, Roads, Hydromodification, Invasives

N/A

Forestry, Roads, Invasives

Forestry, Roads, Invasives, Extraction

Forestry, Roads, Hydromodification, Invasives

Forestry, Hydromodification, Roads, Invasives

Hydromodification, Roads, Invasives

Forestry, Hydromodification, Roads, Invasives

Hydromodification, Roads, Invasives, Atmospheric Deposition

Forestry, Hydromodification, Roads, Invasives

Forestry

Unknown

Forestry

Hydromodification, Roads, Invasives

Forestry

Forestry, Hydromodification, Roads, Invasives

Forestry, Roads

Unknown

Forestry

Forestry, Hydromodification, Roads, Invasives

Forestry

Forestry, Roads

Forestry, Roads, Invasives

N/A

Hydromodification, Roads, Invasives

Forestry, Roads

Forestry, Hydromodification, Roads, Invasives

Hydromodification, Roads

Forestry, Roads

N/A

Roads, Unknown

Forestry, Roads, Invasives

N/A

Unknown

Roads

Forestry, Roads, Invasives

Forestry, Roads, Extraction, Invasives

Forestry, Roads

SELECTION OF BMPS

Multiple federal and state programs provide technical assistance, funding, and regulatory

frameworks supporting tribal nonpoint source management. These programs, administered

through EPA Region 10, Bureau of Indian Affairs, USDA, NOAA, and Washington State agencies,

offer various funding opportunities and technical resources for watershed management (Table 11).

Consultation with regulatory and funding agencies would ensure proposed BMPs align with permit

requirements and grant program priorities, maximizing implementation feasibility.

Table 11. Summary of potential contributors of NPS program implementation.

Organization

Jefferson County

Conservation District

North Paciﬁc Coast Lead

Entity

The Nature Conservancy

Trout Unlimited

Wild Salmon Center

Paciﬁc Coast Salmon

Coalition

10,000 Years Institute

Bullitt Foundation

Russell Family

Foundation

UW Olympic Natural

Resources Center

Type

Local

Government

Regional

Coordinator

NGO

Primary Focus

Technical assistance

NGO

Foundation

Indigenous conservation

Ecosystem restoration

Environmental

sustainability

Research

Academic

Salmon recovery

Land conservation

Coldwater ﬁsheries

Salmon conservation

Salmon advocacy

Services/Support Provided

Conservation planning, cost-share access,

plant sales

Project prioritization, funding

coordination

Scientiﬁc expertise, funding networks

Engineering support, project design

Coldwater refugia, landscape planning

Policy support, coordination

Invasives removal

$25,000-100,000 grants

Indigenous-led conservation

Scientiﬁc studies, landscape projections

Selection Process

Once NPS categories are established the Tribe will choose available BMP’s through expert

consultation and research. Factors such as funding, priority, infrastructure, landscape, season,

collaboration, cultural assessments, risks, outcome success, and salmon health will weigh into the

decision-making process. The Tribe will consult with other agencies and landowners to choose

appropriate BMPs and make formal agreements for implementation projects. The Hoh Tirbal

Business Committee will be consulted before project implementation and for final project

approval. Collaboration with local agencies, the Hoh Tribe, and landowners will be an important

factor in implementation, so public and stakeholder participation will be necessary. Informational

sessions in technical committees and for landowners will be held, and feedback will be

incorporated as the Tribe sees fit. The Hoh Tribal Business Committee has final authority on

implementation practices with cultural and aquatic species protection to guide their priorities. The

Tribe will provide updates regarding plans, outputs, or issues to stakeholders when necessary. Once

BMPs have been selected and implementation is underway, the Tribe will use resources necessary

to ensure successful results, which may include continued long-term monitoring efforts or

maintenance measures.

Current and previous BMP’s have been coordinated and implemented by the Tribe through

multiple gateways, coordinated partnering efforts, and various funding opportunities. The

selection process addressed above was used to accomplish restoration efforts throughout the

watershed. The Tribe has mainly focused on hydromodification and bank erosion mitigation in

recent years (Table 12) to address risks to aquatic life and cultural resources.

Table 12. Summary of previous or active BMPs addressing NPS pollution sources in the Hoh River Watershed.