North Fork Willow Creek

North Fork Willow Creek 2012
Restoration Project (Phase 1)

NFWC Resto

Ken Clark, Water Quality Coordinator                           Water Resources Division – Nez Perce Tribe
or                                                                                              6/12/2012
Casey D. McCormack, Water Technician III
Table of Contents:

North Fork Willow Creek Restoration Project Summary (Phase I) 
Project Goals &Actions
Project Pollutant/Sediment Reduction Overview
Project Status

North Fork Willow Creek Restoration Project Summary (Phase I)

The North Fork Willow Creek property is located SE of Winchester, Idaho on the Nez Perce Reservation just off of Lunders Road, near the Nez Perce Tribe’s Talmaks Reserve. The North Fork Willow Creek flows though crop and pasture lands for approximately three miles, until it flows into Talmaks reservoir, which was created in 1964 by the Bureau of Indian Affairs (BIA) to increase fishing and recreation opportunities for Tribal members. This reservoir effectively dewaters the stream below it by late summer in most years, leaving only a few scattered residual pools. The North Fork Willow Creek property is located approximately 1.2 miles downstream of the reservoir.

NFWC Aerial

Completed riparian restoration activities by the Nez Perce Tribe’s Water Resources Division (NPT WRD) on the North Fork Willow Creek property complement conservation measures implemented by the Natural Resources Conservation Service (NRCS), Idaho Soil and Water Conservation Commission and Nez Perce Soil and Water Conservation District, in partnership with the landowner. A number of best management practices (BMPs) were implemented on the site. These BMPs included installing approximately 1,525 feet of fencing to exclude cattle from the riparian zone, two off-site watering troughs, and the construction of a pond designed by NRCS engineering staff.

The NPT WRD staff planted over 1,000 riparian plants, ranging from 1-5 gallons in size, along the creek and installed approximately 400 feet of wetland sod at key locations in the stream channel. Bioengineering techniques were utilized to stabilize eroding stream banks, and a series of small debris dams were installed to slow stream velocities and encourage the deposition of sediment and, as a result, aggradation of the stream channel. Approximately 30 lodgepole pine trees were planted on an upland slope to help limit thermal loading to the stream by providing shade, as well as providing habitat for local wildlife.


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Photos above: 
Woody Plants 
(Black Cottonwood, Blue Elderberry, Common Snowberry,Coyote Willow, Golden Currant, Mackenzie Willow, Mountain Alder, Ponderosa Pine, Lodgepole Pine,Quaking Aspen, Red Osier Dogwood, Serviceberry, Thinleaf Alder)

Wetland Sod Mats
(Mats consisted of Herbaceous Perennials including:
Baltic Rush, Beaked Sedge, Hardstem Bulrush, and Nebraska Sedge).


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Photos Above:
Stock pond and offsite watering

Project Goals & Actions

This project was funded and implemented by the NPT WRD Clean Water Act (CWA)-§319 Program. The primary goal of the §319 Program is to control or prevent nonpoint source (NPS) pollution, which is the leading source of water quality impairment on the Nez Perce Reservation. This goal is achieved by implementing targeted BMPs to reduce pollutant loading. The NPT WRD is committed to restoring and protecting the aquatic environment to support designated uses for aquatic life, protect drinking water, restore recreational opportunities, and preserve the ceremonial use of these waters.

1. Improve Water Quality by Controlling and Preventing NPS Pollution

  • Reduce bacteria and nutrient levels by installing 1,525 feet of fencing to remove stock access to the stream.
  • Reduce sediment loading by installing wetland mats to stabilize eroding streambanks, lower water velocity and increase sediment deposition.
  • Improve filtration of overland runoff using native grasses and riparian plantings. The removal of stock access in the riparian zone will encourage the growth and spread of native grasses, thereby increasing the filtering capacity of the riparian zone. Decrease solar loading to stream by restoring in-stream cover and riparian canopy.

2. Improve Stream Hydrology

  • Encourage aggradation of streambed and increase storage of subsurface water in floodplain/streambanks by introducing small scale debris dams to reduce water velocity and increase deposition of sediment.
  • Plant diverse riparian vegetation to help increase infiltration rates, elevate the water table and saturated zone, and increase water storage.

3. Restore and enhance the riparian zone

  • The installation of over 1,000 riparian plants will help to stabilize streambanks and provide much needed shading to the North Fork Willow Creek, in addition to providing good habitat for wildlife, fish and other aquatic organisms.
  • Improve fish and wildlife habitat by providing attributes like forage, cover, and instream habitat. The addition of a diverse riparian ecosystem will enhance cover for birds, fish and other wildlife.
  • The installation of offsite watering locations and exclusionary fencing will remove stock access to the stream, reducing erosion rates and soil compaction rates, which will increase infiltration rates and improve the health of vegetation within the riparian zone.

Project Pollutant/Sediment Reduction Overview

The completion of this project will significantly reduce the amount of sediment, nutrients and bacteria being delivered to the North Fork Willow Creek. In 2008-2009, the Idaho Association of Soil Conservation Districts (IASCD) monitored Willow Creek, which the North Fork Willow Creek flows into, approximately one mile from the project site. Willow Creek is a tributary to Lawyer Creek. Table 1 lists the descriptive water quality statistics from the IASCD Willow Creek monitoring project.

Table1. Descriptive statistics for Willow Creek, 2008-2009

stats for willow creek

DO= Dissolved oxygen, Temp= water temperature, E. coli= Escherichia coli, NO2+NO3= nitrate plus nitrite, TP= total phosphorus, NH3=Total Ammonia, SSC=suspended sediment concentration


  • Nutrients: Although there is no numeric standard in place for NO2+NO3, some literature claims that numbers above 0.3 mg/L could cause excessive plant growth and possible eutrophication (Cline, 1973; Golterman, 1975). For the analysis of this data, 0.3 mg/L was used as the water quality target. The Environmental Protection Agency (EPA) developed a national guideline of 0.1 mg/L total phosphorus (TP) for streams (EPA 1986). This target was used in the evaluation of the monitoring data during the May through October growing season.
  • Sediment: Literature suggests that suspended sediment concentration (SSC) levels below 25 mg/L are ideal for the protection of fisheries, and at this level there are no harmful effects on fish or fisheries (DFO, 2000).
  • Temperature: The cold water aquatic life (CWAL) criteria for Idaho streams states that water temperatures must be 22° C or less with a maximum daily average of no greater than 19° C. Lawyer Creek and its tributaries are also listed for Salmonid Spawning (SS), which means that water temperatures must be 13° C or less with a maximum daily average no greater than 9° C during salmonid spawning and incubation periods.
  • Bacteria (E. coli): 126 cfu/100mL as a geomean. 406 cfu/100 mL as an instantaneous measure for primary contact recreation and 576 cfu/100 mL instantaneously for secondary contact recreation.
  • Dissolved Oxygen: must exceed 6 mg/L at all times.
  • The Idaho Administrative Procedures Act (IDAPA), section, contains the Surface Water Quality Criteria for Aquatic Life Use. Criteria for total ammonia nitrogen (TAN), and pH are found there and were used in the evaluation of the monitoring data.

A single E-coli exceedance was recorded at this site on June 4, 2009. The most likely source is livestock presence within the riparian area. The primary water quality concerns in this drainage area are water temperature and excess sediment. Half of the instantaneous temperature measurements exceeded the criterion, and several turbidity and sediment target exceedances were also recorded at the Willow Creek monitoring site.

Removing livestock access to streambanks at the North Fork Willow Creek project site is expected to help stabilize streambanks and decrease the volume of eroding sediment that would have previously been delivered during annual snowmelt and high streamflow runoff. Potential sediment delivery will return to a natural background condition once the streambanks have become fully re-established. The direct volume calculation used by NRCS (1983) is an applicable method for estimating the sediment load reduction for streambank stabilization. This method evaluates percentage of erosive streambank, develops lateral recession rates based on local data or literature values, and provides equations to calculate the quantity of sediment delivered by the percentage of erosive streambanks. A worst case scenario could consider that the streambanks were 100% erosive. A 100% erosive streambank has a lateral recession rate of 0.5 feet per year. With time allowed for reclamation, the streambanks could become minimally erosive, with a lateral recession rate of 0.01 feet per year. Eroding volume is calculated by the equation:

E = [A *R LR * D ]/2000 lbs/ton


E = bank erosion over sampled stream reach (tons/year/sample reach)

AE = eroding area (ft2)

RLR = lateral recession rate (ft/yr)

DB = bulk density of bank material (lbs/ft3)

Nutrients adsorb to silt particles in sediment at an approximate ratio of 1.6 pounds per ton for phosphorus and 3.2 pounds per ton for nitrogen, according to the Section 319 watersheds training manual (Michigan DEQ, 1999).

Pollutant load reduction estimations for the North Fork Willow Creek restoration site are summarized in Table 2.

Table 2. Load reduction estimates for North Fork Willow Creek fencing and restoration project, Phase I

Project Name, Location and Parameters Calculation/Estimation Method Load Reduction
North Fork Willow Creek fencing and streambank restoration


Direct Volume Calculation


Sediment =228 tons

Nitrogen =730 lbs

Phosphorus=365 lbs



North Fork Willow Creek

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Photos Above:
North Fork Willow Creek property assessment 7/8/2010: Note the Eroding streambanks, lack of riparian vegetation, and excessive algal growth. The completed exclusionary fence can be seen in the photos above.

Project Status


The NPT WRD planted over 1,000 riparian plants, ranging from 1-5 gallons in size, along the creek and installed approximately 400 feet of wetland sod at key locations in the stream channel. Planting took place during the spring of 2011.
The wetland sod was grown by the WRD in Lapwai, ID in plastic lined boxes under flooded or permanently saturated conditions ensuring the plants were relatively mature with well developed root systems and high shoot cover.  By using the vegetated coir erosion control mats grown with native wetland plants the WRD was able to provide immediate aesthetics, weed inhibition, and stabilization to the eroding streambanks on the property.
Irrigation occurred throughout the summer and fall in order to increase survival rates and ensure healthy root development. Irrigation was accomplished using a small Honda water pump, a 50 foot garden hose, and water from the stream.
During the late summer and early fall Northfork Willow Creek dried up requiring water to be brought onsite using a 300 gallon tank secured in the bed of the WRD work truck. Plants were then watered using a tank sprayer attached to a four-wheeler or hand watered using five gallon buckets in those areas the four-wheeler could not access.

Two check dams were installed using interlocking six foot conifers during the summer of 2011 to aid in sediment capture and stream aggradation. However, high flows during the spring of 2012 washed out both check dams.Time and resources permitting, new check dams will be installed during the summer or fall of 2012 along with willow stakes to help secure the check dams to avoid future blow outs during high water events. The Nez Perce Soil and Water Conservation District donated an additional 350 upland trees and planting was completed with the help of the Idaho Correctional Institution-Orofino work release program crew during the spring of 2012. Donated plants included Blue Elderberry, Golden Currant, Quaking Aspen, Red osier Dogwood, and 150 ponderosa pine trees. Additionally, approximately 400 willow stakes collected along the Clearwater and Snake Rivers will be planted using a water stinger in the fall of 2012. A water stinger is a metal pipe about 1 inch in diameter and 6 feet long with handles that attaches to a garden hose fitted to a pump. The stinger digs a hole with pressurized water, making it easier to get the willow poles to the proper depth so rooting can take place

The North Fork Willow Creek project will continually be monitored using established photo points and a meter board. Photographs will be taken annually to assess the success of the restoration project.


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Photos Above: Planting and watering activites – Spring of 2011.
Note wetland mat along toe of eroding streambank in bottom left photo.