Provided for:
The Yakama Nation on behalf of its YKFP
Fisheries Program
P.O. Box 151, Fort Road
Toppenish, WA 98948
White Creek 191 Meadow
Habitat Enhancement Project
60% Design Report March 8, 2019
White Creek 191 Meadow
Habitat Enhancement Project
60% Design Report:
Provided for
The Yakama Nation on behalf of its
YKFP Fisheries Program
P.O. Box 151, Fort Road
Toppenish, WA 98948
Prepared by
Inter-Fluve, Inc.
1020 Wasco Street, Suite I
Hood River, OR 97031
541.386.9003
September 28, 2018
SEPTEMBER, 2018 I
Table of Contents 1. Introduction ...............................................................................................................................1
2. Field Survey ................................................................................................................................1
3. Hydrology ...................................................................................................................................3
4. Hydraulic Model .........................................................................................................................4
5. Design ........................................................................................................................................6
6. Construction – Contract documentation .................................................................................... 11
7. References ............................................................................................................................... 12
8. Appendix A: Design Drawings ......................................................................................................2
9. Appendix B: Hydraulics ...............................................................................................................3
10. Appendix: Revegetation Prescription ..........................................................................................4
List of Figures Figure 1. Photograph showing bank composition and gravel lenses 1-2 feet below top of bank. .................. 2
Figure 2. Photograph showing inset floodplain development with willow (right) following lateral bank
migration of silt dominated bank (left). ..................................................................................................... 3
Figure 3. Cross-section geometry used in HEC-RAS model. ......................................................................... 5
Figure 4. Drone photograph within the project depicting both the loss of channel length and eroding
laterally migrating right channel bank. Water flow is from the bottom of the photo to the top. .................. 7
Figure 5. Inundation map of modelled existing conditions (left) and design conditions (right) during the 2-
year return discharge. .............................................................................................................................. 9
List of Tables Table 1. Weather stations in the vicinity of the White Creek study area considered for hydrology. ............. 4
Table 2. Recurrence interval flows calculated for the project reach. ........................................................... 4
Table 3. Activity categories and risk included in the project. .................................................................... 10
Appendices Appendix A - 60% Design Plans
Appendix B – Hydraulic Model
Appendix C – Revegetation Prescription
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1. Introduction
White Creek is a 4th order tributary of the Klickitat River that provides spawning and rearing
habitat for mid-Columbia ESA-threatened steelhead and resident rainbow trout. The White Creek
191 Meadow project reach is approximately 1800 feet long within a segment of former wet meadow
that has become degraded over time. The contributing watershed area above the project reach is 45
square miles. The goal of the project is to improve the quantity of valley bottom wetlands but more
importantly, increase large wood related rearing and holding habitat in pools for resident trout and
anadromous steelhead.
2. Field Survey
Field survey was conducted October 12, 2017. The project area was walked to identify and survey
potential treatment sites, general bedload and transport characteristics, and survey cross-sections for
hydraulic modeling. Survey was completed using RTK GPS and Total Station survey equipment.
Temporary control points were established throughout the project site and permanent control along
the valley toe near a forest road and adjacent to the meadow.
Ground survey data were supplemented with pre-existing LiDAR data to produce a three-
dimensional surface of the project area. Ground survey and LiDAR data compared well. Cross-
sections for the hydraulic model were extracted from the surface where appropriate. LiDAR was
used to supplement Total Station survey, design grading, base map production and both 1 and 2D
hydraulic modelling. Field photos were used to document existing conditions, bedload
characteristics, and potential project work areas.
2.1 SITE CONDITIONS
Throughout the valley bottom, an open mixed stand of younger pine and fir exists with an
understory of fescue and other grass on dryer valley bottom surfaces. Willow, sedge, snowberry and
spirea were observed within lower and wetter areas within and adjacent to abandoned channels,
and in recent depositional areas within the eroding bank boundaries.
Eroding banks have a 1-2-foot layer of silt loam forming the topsoil. Below the silt loam, there are
variable strata of gravel lenses, dense silt/clay layers forming the lower portions of exposed banks.
The sublayers beneath the valley bottom topsoil are inconsistent along the bank margins in the
project reach. Bank margins with greater clay content appear to be more resilient than banks
composed of gravel, sand and silt. Some areas show evidence of recent bank failure.
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Figure 1. Photograph showing bank composition and gravel lenses 1-2 feet below top of bank.
The streambed at the project site currently occupies a local gravel/cobble layer that is mostly
composed of on/near site material in the lower banks and bed. Upper bank soils are silt.
Composition on stepper riffles is cobble and gravel, and 1” minus gravel and sand on gravel bars.
Willows are colonizing the tops of many gravel bar deposits, which suggests a stable inset
floodplain has formed in some areas.
The channel has incised through the meadow due to basin-scale influences outside of the project
area. The degradation likely occurred rapidly through the sandy silts in the upper soil profile, but
the stream is now nestled into the gravel cobble layer, which the stream is being worked into pools,
riffles, and bars. Little coarse grain material comes from the upper watershed, which is composed
largely of fine grained soils and to a lesser degree, sub-angular cobbles. The relatively rich supply of
cobble and gravel at the site appears to be a localized resource (site scale). The cobble is
demonstrated to be heavily utilized by spawning steelhead.
Gravel
Silt Loam
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Figure 2. Photograph showing inset floodplain development with willows (right) following lateral bank migration of silt dominated bank (left).
3. Hydrology
No stream gage data exists on White Creek to calculate peak flow statistics directly. Therefore,
regional regression equations were used to estimate peak flow hydrology at the project site. These
floods were used in hydraulic modeling to help understand channel-forming characteristics and
associated stage discharge elevations with observed vegetation and sediment deposition
characteristics.
The regional regression equations were obtained from the report titled USGS Scientific Investigations
Report 2016-5118 Magnitude, Frequency, and Trends of Floods at Gaged and ungagged sites in Washington,
which is based on data through water year 2014 (Mastin et al. 2016). Within the report, Washington
State was divided into four regions. Each watershed that has a stream gage was statistically
compared to watersheds in the same region without gages and regression equations were developed
for ungagged sites. White Creek lies on the boundary of Region 2 and Region 4, which provide
varied results. Therefore, we developed equations for both regions to determine which region best
represents the flows for the White Creek project site. Determining which region was most
representative was an iterative process completed as part of the hydraulic modeling effort and
involved comparing field indicators of channel forming discharge surveyed within the hydraulic
cross-sections, with equation results for the 2-year discharge in both regions.
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Mean annual precipitation (MAP) is used within each equation. To determine a range of appropriate
MAP values to input to the equations, average annual precipitation data was acquired from the
Western Region Climate Center, which publishes data and statistics for four sites in the region
(Table 1).
Table 1. Weather stations in the vicinity of the White Creek study area considered for hydrology.
Name Network Station # Elevation (ft) Average Annual
Precip. (in)
Glenwood 2 COOP 453184 1850 30.74
Goldendale2 COOP 453226 1700 15.49
Status Pass WDOT 457340 3116 21.98
Status Pass2 COOP 457342 2610 22.64
Through an iterative process within the modeling effort, we found that the MAP that matched most
closely with the site channel forming indicators was within the low end of the range found within
stations in Table 2 (A MAP between 15 and 22 inches) and equations developed for Region 2 were
more representative of field indicators than Region 4. Discharge used for hydraulic modelling for
existing and design conditions are provided below.
Table 2. Recurrence interval flows calculated for the project reach.
Recurrence
Interval
2-Year 5-Year 10-Year 25-Year 50-Year 100-
Year
Flow (cfs) 113 345 620 1140 1710 2420
4. Hydraulic Model
The hydraulic analysis used the U.S. Army Corps of Engineers’ Hydraulic Engineering Center River
Analysis System (HEC-RAS 5.0.3; USACE 2016). HEC-RAS is a computer program that models the
hydraulics of water flow through natural rivers and other channels. A steady-state, one-dimensional
model was run in order to perform hydraulic computations to determine channel-forming flows
within the project area by comparing hydraulically-modeled peak-flow hydrology estimates with
field surveyed channel-forming stage estimates. The existing conditions HEC-RAS model was
developed using the best available data and is a representation of the physical terrain along White
Creek and adjacent floodplain surfaces.
HEC-RAS cross-sections were spatially drawn to sample the surveyed cross-sections on the ground,
span the 100-year flood inundation extents at hydraulic controls, and traverse sites where habitat
improvements are likely to occur. Cross-sectional geometry was extracted from the three-
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dimensional topographic LiDAR used to supplement total station survey. The locations of hydraulic
cross-sections are shown in Figure 3 below.
Figure 3. Cross-section geometry used in HEC-RAS model.
The model was run in steady-state under mixed flow regime to represent peak floods on existing
conditions. The boundary conditions were set to normal depth at the average slope at upstream and
downstream ends of the study reach. Manning’s ‘n’ or roughness values correspond with various
types of land cover and channel characteristics (Table 3). Values are consistent with field
observations as well as published guidelines for channel types and vegetation conditions (Arcement
& Schneider 1989).
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Table 3. Roughness coefficients used in the hydraulic model.
Description Manning’s n
Channel, cobble bed, bars and banks 0.034
Gravel bars with sparse vegetation and discontinuous LWD 0.05
Gravel bars dense willow or woody debris 0.06-0.07
Floodplain, grass (smooth) 0.04
Floodplain, shrubs (rough) 0.10
The proposed conditions model was developed by copying the existing conditions model and
editing the geometry to represent earthwork, block obstructions, and changes in roughness to reflect
the design. Results show that water surface elevations for all floods are little changed by the
proposed actions, but largely there are small increases in stage and inundation widths. Detailed
model output comparing existing to proposed conditions is in Appendix B.
5. Design
The proposed design seeks to increase riparian wetland and instream habitat by placing imported
large wood log jams within excavated lowered banks at existing eroding meander bends and
inflections. The 191 Meadow is one of many stringer meadows that have lost channel length and
become locally incised, losing contact with former floodplain surfaces. The valley bottom became
perched and disconnected from frequent seasonal flood inundation, causing significant drying and
plant ecology changes over much of the former meadow surfaces. Areas that were once likely sedge
and willow are now grass and pine. The incision places greater pressure on channel banks, which
over time, laterally erode and re-develop new flood-prone surfaces at lower elevations that are inset
within the now abandoned former valley bottom.
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Figure 4. Drone photograph within the project depicting both the loss of channel length and eroding laterally migrating right channel bank. Water flow is from the bottom of the photo to the top.
5.1 ALTERNATIVES
In some cases, incised channels can be filled and raised up to restore connection to former floodplain
surfaces. We do not think the 191 Meadow is a good candidate for this strategy because it has
already experienced significant lateral migration, forming an inset floodplain, which would require
a large fill volume to raise the channel bed. Furthermore, there is no reasonable downstream
location for establishing a stable grade control to step down a lifted creek segment to the incised
channel downstream of the project reach.
Adding large wood in locations and configurations that would accelerate lateral channel migration
and inset floodplain development was considered but disregarded. Further meandering at the site
might expose additional cobbles, which are good for the system and steelhead, but the thick upper
layer fine soils also recruited through bank erosion would be a significant impairment to the system
and fish health.
The proposed enhancement actions are somewhat consistent with the latter alternative. The project
would create new floodprone surfaces consistent with the elevations of inset floodplains that have
been gradually developing naturally. In this way, the configuration would be consistent with the
natural process trajectory, but without introducing fines to the stream. This will increase wetland,
restore meadow connection to hydrology, increase floodplain area for fish refuge and foraging
during high water – all while preserving the hydraulic conditions that provide and maintain existing
spawning habitat.
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The project would improve future riparian floodplain by selectively excavating 0.77 acres of new
floodplain surfaces that will become inundated during 2-year discharge estimate. The new surfaces
will support willow (gravel) and sedge (silt/clay) vegetation depending on the substrate
encountered at the new floodplain surface. Based on the variability in bank substrate, we expect the
same variability in areas excavated that are adjacent to current banks. Imported trees and logs will
be used to construct large wood accumulations on the new floodplain surfaces. Portions of the large
wood will be in contact with pools on the stream.
The lowered surfaces provide inundation areas, while the large wood creates ineffective flow. The
water surface elevations of floods will not change, and the frequency of flood inundation upon the
perched floodplain will not change significantly from current conditions. However, the extent of
inundation will be markedly increased for smaller and more frequent floods (<5yr). Improvements
in floodplain inundation are evident in the comparison of existing to proposed conditions models of
the 2-year flood (Figure 5).
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Figure 5. Inundation map of modeled existing conditions (left) and design conditions (right) during the 2-year return discharge. A total of 0.77 acres of new wetland inundation will be created during the 2-year discharge.
To enhance habitat further, existing pool areas will be excavated in areas associated with bank and
valley bottom excavation sites. Large wood will be placed to provide cover habitat over existing
enhanced pools and within lowered segments of valley bottom to provide resiliency and roughness
until wetland vegetation can become fully established.
All construction work will be completed during low/no-flow conditions the project reach
experiences in the late summer. A summary of HIP activities is described in Table 4 below.
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Table 4. Activity categories and risk included in the project.
Description of Proposed Enhancement Work Element HIP III
Category
HIP III Risk Level
Log structure construction to improve main
channel habitat suitability and stability
Install habitat-forming
natural material
instream structures
2d Medium
Low floodplain enhancement to improve off-
channel habitat
Improve secondary
channel and wetland
habitats
2a Medium
Revegetation of all disturbed surfaces Riparian vegetation
planting
2e Low
5.2 DESCRIPTION OF PERFORMANCE/ SUSTAINABILITY CRITERIA FOR PROJECT ELEMENTS
AND ASSESSMENT OF RISK OF FAILURE TO PERFORM, RISK TO INFRASTRUCTURE,
POTENTIAL CONSEQUENCES, AND COMPENSATING ANALYSIS TO REDUCE UNCERTAINTY
Infrastructure and flood risk
Imported logs specified for the project will be self-stable during floods up to the 100-year flood.
Although each log could be expected to shift during a large flood, it would not move a significant
distance from its original placement due to its length, weight, and root wad. The introduced wood is
expected to somewhat increase side channel scour and floodplain complexity over time. There is no
infrastructure in the area that can be impacted. An existing forest road will be re-located to the toe of
the valley slope. Although the road can be flooded, there is no increase in flood hazard compared to
existing conditions.
Design criteria
Design criteria for large wood are as follows:
Wood used in this project will be naturally stable and will remain on site up to the 100-year
return peak flow.
Large wood habitat will be placed and oriented to be engaged with the creek, providing
habitat year-round, and to provide sediment sorting and small woody debris capture during
high water. Floodplain grading will increase total inundation zones. Frequency of
inundation will be at the same stage and will not change from pre-project conditions.
Risk of failure to perform
Current migration rate, planform condition and grading designs are conducive to the proposed
project. The channel is well suited to wood treatments that will provide cover habitat in existing
pools, capture small woody debris, maintain spawning gravel, pool scour and associated riparian
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complexity at low and high flows. There is very low risk that importing large wood and floodplain
grading will fail to improve channel and floodplain habitat.
5.3 STABILITY ANALYSES AND COMPUTATIONS FOR PROJECT ELEMENTS, AND
COMPREHENSIVE PROJECT PLAN
Stability analysis and computations for project elements followed professional practice guidelines
for large wood design (Knutson and Fealko 2014 and USBR and ERDC 2016), stream habitat
restoration (Cramer 2012), Stability of Ballasted Woody Debris Habitat Structures (D’Aoust and
Millar 2000) and institutional knowledge combined with professional judgment for the design of
specific project elements. The size of the large wood sourced for the project greatly exceeds the
ability of the highest discharges to move the wood. Therefore, the wood is considered self-stable
and will not require ballast.
6. Construction – Contract documentation
6.1 INCORPORATION OF HIPIII GENERAL AND CONSTRUCTION CONSERVATION MEASURES
Conservation measures will be included in construction contracting. Variances will be submitted as
required for conservation measures that are not met by the project design. No variances are
expected. The project will be constructed during the low-flow/no-flow period between August and
early-October, dependent upon observed conditions.
6.2 DESIGN – CONSTRUCTION PLAN SET
Construction design drawings will be updated as necessary to the level required for field directed
construction.
6.3 LIST OF ALL PROPOSED PROJECT MATERIALS AND QUANTITIES
Final large wood numbers (volume) will be included in future permit design phases. Imported and
placed large wood/trees are the only proposed material for the project.
6.4 DESCRIPTION OF BEST MANAGEMENT PRACTICES THAT WILL BE IMPLEMENTED AND
IMPLEMENTATION RESOURCE PLANS INCLUDING:
Site access staging and sequencing plan
Work area isolation and dewatering plan
Erosion and pollution control plan
Site reclamation and restoration plan
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7. References
Arcement, George J. Jr and Verne R. Schneider, 1989 “Guide for Selecting Manning’s
Roughness Coefficients for Natural Channels and Flood Plains”, USGS Water-Supply Paper 2339
Maston, M.C., Konrad, C.P., Veilleux, A.G., and Tecca, A.E., 2016, Magnitude frequency, and
trends of floods at gaged and ungagged sites in Washington, based on data through water year 2014
(ver 1.2, November 2017): U.S. Geological Survey Scientific Investigations Report 2016-5118, 70p.
Appendix A: Design Drawings
Appendix B: Hydraulic Model
Appendix: Revegetation Prescription