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Spokane RiverkeeperVolunteer information and Registration for the Dec 2023 – June 2024 season

Project Summary:

Help us to collect scientific data to protect the Spokane River! You will monitor water clarity (turbidity) in the Spokane River and Hangman Creek.  We will use these determine the intensity and duration of degraded water quality in Hangman Creek and its effect on the Spokane River.  Sign up at the “Select Sampling Dates” button below to sign up for dates to volunteer.  Check out the video below for a quick overview of what you’ll be doing.  Make sure to get trained if you haven’t already by signing up for a training date.

Quick Start & Important Links

Registration & Waiver FormVolunteer Training RegistrationSelect Sampling DatesSampling Data Entry FormView the 2021 ReportView the 2022 Report


Hangman Creek has suffered extreme degradation in the form of loss of riparian habitats and function, the ditching of wetlands and loss of wetland function, as well as excessive drainage systems originating in agricultural operations and running into the creek. Additionally, the Palouse loess soils have been routinely exposed through tillage practices that exacerbate erosional runoff of sediment and phosphorus (ref).  As many as 200,000 tons of topsoil runoff and into Hangman and the Spokane River each year.  Hangman has been studied but the Spokane River has received little attention to the impacts of sediment inputs on the aquatic biology of the Spokane River system.

Few if any agencies or scientists are watching the phenomenon of sediment entering the Spokane River seasonally from Hangman Creek each year.  Little is understood about the amount of sediment, its origins, or the implications for disrupting Redband trout spawning, feeding behavior or the substrate that provides habitat requirements for salmonids and other fish.  Additionally, little is known about its impacts on the benthic community, and its contribution to the nutrient loading in the Spokane’ river system.  This sediment input can be assumed to change the trophic response and behavior of the river system in a multitude of ways.

Washington State Department of Ecology currently samples at the mouth of Hangman Creek and downstream of the Hangman mouth at the Spokane River at Riverside State Park and at the Nine Mile Bridge.  These data, from monthly sampling events, suggest that turbidity from Hangman Creek influences the Spokane River.  Hangman Creek is a notoriously flashy watershed, sometimes rising and falling thousands of cubic feet per second in a day, bringing with it the associated sediment.  Monthly sampling is not sufficient to capture these flashy events.  More frequent sampling will record the intensity and duration of Hangman Creek’s sediment plume in the Spokane River.


Turbidity readings will be taken several times per week from Hangman Creek and the Spokane River above and below the mouth of Hangman Creek between December 1, 2021 and July 1, 2022.  Samples will be taken in Hangman at Peoples Park or the 11th Street Bridge, in the Spokane River at Sandifur Bridge, below the TJ Meenach Bridge and below the Hangman Creek confluence with the Spokane River.  Turbidity will be determined using a transparency tube and recorded in centimeters. Readings from Sandifur Bridge samples will be compared to readings from the TJ Meenach samples to determine the effect of Hangman Creek on the Spokane River.

In locations where the river/creek is not accessible from land, a jar/bucket will be lowered into the water with a rope off of a bridge.  Water will be hauled up in the container and analyzed for turbidity.

Spokane River Hangman Creek confluence
Map Spokane River sediment study locations

Water Sample – Sampling Video

Photo Documentation of Sediment Plume

mouth Hangman Creek dumping sediment in Spokane River

Example photo from photo point at corner of Summit and Broadway

Volunteers will take photos (landscape format only please!) of the sediment plume from the corner of Summit and Broadway on the Centennial Trail during each monitoring run.  Photos will be combined to visually show the impact of Hangman Creek on the Spokane River.

Results will be recorded on the datasheet included below.  Make sure to note the weather patterns or unusual results in the notes section.

Training and Reporting

Please register for one or both training sessions as this is a requirement to participate in the study. If you have questions or need more information please contact

Volunteers will report results back to the Spokane Riverkeeper weekly.


The safety of volunteers should take priority over any data collection.  Please do not attempt to take water quality samples in slippery conditions, such as on ice or snow. Participants must have a waiver on file that is signed. See the form for the online waiver below. If you have not completed the form and electronically signed the consent waiver you cannot participate in the study. Sorry, no exceptions.

Project Outline:

Sampling water clarity (turbidity) Spokane River at mouth of Hangman Creek

Sampling water for clarity (turbidity) data

Volunteers would collect water samples, flow, turbidity and photo data at points along the Spokane River and Hangman Creek through the winter of 2023/2024 and into the summer of 2024.

1. Volunteers will collect turbidity/transparency data:

  • Above confluence with Hangman Creek in the Spokane River at Sandifur Bridge
  • Mouth of Hangman Creek at 11th Street Bridge
  • Below the confluence of Hangman Creek and the Spokane River (near the cemetery)
  • In the main stem of Spokane River at TJ Meenach Bridge

2. Volunteers will take a landscape photo at:

  • North Summit Street and W. College – find the Green Zip Ties on the fence.

Project Site Descriptions:

11th Street bridge: At the south end of High Bridge Park. I usually park at the west end of the bridge by the gate. This is the sample taken off the bridge.

Sandifur Bridge: Park in the People’s Park parking lot and walk down to the river if not too icy. I usually walk down to the river about 100 feet upstream of the bridge

Riverside Memorial Cemetery: Drive into the Cemetery and stay right. The parking pull-off is on the far western/southwestern corner of the cemetery. An old road leads down to the river.

TJ Meenach: Access the river at the TJ Meenach Parking lot on the northern side of the river and downstream (west) side of the bridge.

Photo Evidence

Potential Future Research Questions/implications:

  • What are the impacts of excessive sediment pollution to O Mykiss habitat and behavior?
  • What are the impacts to the benthic invertebrate communities that provide a food base for native fish, what are the effects on non-salmonid native fish in the food web, effects on algae growth and dissolved oxygen in aquatic systems/River.

Hangman Creek – Spokane River Community Science Sediment Study Data Report

View the 2022 ReportView the 2021 Report

Volunteer Sampling Calendar

Click here to view the calendar and pick your dates!

Transparency/Turbidity Data Sheet

Volunteers will input data on the paper form and submit that data online here. The form will input data as follows:


Location Date Time Name Transparency

Turbidity reading (CM)

Flow Hangman Creek Flow Spokane River Notes

(Weather, Precipitation, temp,  etc)

2024 Turbidity Study Project Registration/Waiver

Please use this form to register for SFTU's Community Science Spokane River Turbidity Study Project.

Expected Start: 1st week of January 2024
Expected End: July 1st 2024
1st Training Date: Virtual: December 14th, 2023, 7:00pm
2nd Training Date: In Person: January 13th, 2024, 10AM, 11th Street Bridge

We recommend a minimum of 2 person teams for safety but this is not required.

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