Tillicum Fan Habitat Restoration Concepts Report

Submitted to Yakama Nation Fisheries

March 2017 Tillicum Fan Habitat Restoration Concepts Report

Mac r h 2017

Submitted to Yakama Nation Fisheries 401 Fort Road Toppenish, WA

prepared By Inter-Fluve, Inc. 501 Portway Ave, Suite 101 Hood River, OR 97031 (541) 386-9003 Tillicum Fan Habitat Restoration Concepts Report

Table of Contents

INTRODUCTION ...... 1 Overview ...... 1 Project Area Description ...... 1 Goals and objectives ...... 2 Regional Habitat Objectives and Priorities ...... 2 SITE CONDITIONS AND ANALYSIS ...... 3 Site Survey and Data Collection ...... 3 Geomorphology ...... 6 Hydrology ...... 7 Hydraulic Modeling ...... 8 PRELIMINARY DESIGN CRITERIA ...... 9 Habitat ...... 9 Geomorphology/Hydrology ...... 9 Engineering and Risk ...... 9 Construction Impacts ...... 10 CONCEPT DESIGNS ...... 10 Concept 1: Fan Swale Extending to Mad River ...... 12 Concept 2: Short Fan Swale Extending to Mad River Relic Channel ...... 13 Concept 3: Long Fan Swale Extending to Mad River Relic Channel ...... 14 Designer’s notes on configurations ...... 14 REFERENCES ...... 15

Attachments – Plans and estimates

Appendix 1 – Stream substrate pebble count data

Appendix 2 – Stream hydrology

Appendix 3 – Hydraulic modeling output

i Tillicum Fan Habitat Restoration Concepts Report

1. Introduction

OVERVIEW This report presents field investigations and development of concepts for opportunities to enhance stream processes and aquatic habitat at the Tillicum Creek Fan project area. The project proposes to improve stream processes and riparian conditions to enhance aquatic habitats for Endangered Species Act (ESA) listed Chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss).

PROJECT AREA DESCRIPTION Tillicum Creek is a tributary to the Mad River at River Mile 1.92, approximately 10 miles northwest of Entiat, in Chelan County, Washington, near the intersections of Mad River Road (119A) and Forest Service Roads 5700 and 5800. The Mad River is tributary to the Entiat River near the unincorporated community of Ardenvoir. Tillicum Creek has formed an alluvial fan that terminates along 560 feet of the Mad River and extends up the Tillicum Valley 700 feet where Tillicum Creek flows out of a confined valley and expands radially across the wider fan surface. The fan is bounded on both sides by steep valley walls. Forest Road 5800 runs along the toe of the north valley wall and Tillicum Creek runs along the toe of the south valley wall. The project area of Tillicum Creek and fan and right bank of Mad River encompasses approximately 3.57 acres. The entire project area is located on land owned by the U.S. Forest Service.

Tillicum Creek is entrenched and confined in some locations by a levee, preventing hydrologic connection to the full width of the historic fan limits. The fan is predominantly open field that is grazed seasonally. The banks of Tillicum Creek and Mad River are vegetated with riparian trees.

March 2017 1 Tillicum Fan Habitat Restoration Concepts Report

Figure 1. Location of the Tillicum Creek watershed and the project area.

GOALS AND OBJECTIVES

Regional Habitat Objectives and Goals Regional objectives for salmonid habitat protection and restoration in the Upper Columbia Region have been evaluated and summarized in the document A Biological Strategy to Protect and Restore Salmonid Habitat in the Upper Columbia Region (2014) by the Upper Columbia Salmon Recovery Board (UCSRB) Regional Technical Team (RTT). This Biological Strategy is part of the Upper Columbia Spring Chinook Salmon and Steelhead Recovery Plan (UCSRB 2007). It recommends region‐wide biological considerations and approaches for salmonid habitat restoration and protection actions. The RTT guides the development and evaluation of salmonid recovery projects within the Upper Columbia Region.

The Biological Strategy has identified several assessment units within the Entiat River watershed, including the Mad River assessment unit which includes the Tillicum Creek fan project area. The Mad River is a Tier II priority and the project area is within an area known to provide spawning and rearing habitat for steelhead and rearing habitat for spring Chinook.

March 2017 2 Tillicum Fan Habitat Restoration Concepts Report

The Biological Strategy notes factors affecting habitat conditions to include historical sheep grazing and timber harvest practices, which have both increased upland erosion and sediment delivery to the stream. Further, the Mad River Road constricts the main stem channel at the project area. Ecological concerns include:

 Channel structure and form  Sediment conditions  Riparian conditions  Food  Habitat quantity. The primary project goal is to improve stream process and associated habitats along the Tillicum Fan by creating improved hydrologic connectivity of Tillicum Creek with its fan, and Mad River with its floodplain, along the distal end of the Tillicum fan. Improved stream processes will enhance habitat complexity, create wetland and riparian vegetative communities, and possibly access to ground water inflow. 2. Site Conditions & Analysis

SITE SURVEY AND DATA COLLECTION Topographic and bathymetric data were collected October 2, 2016 using total station survey equipment. The data collection focused on capturing channel cross sections for hydraulic modeling, as well as topography of the fan for mapping and concept designs. Temporary benchmarks were placed throughout the project site for future reference. Survey is based on a project relative datum.

March 2017 3 Tillicum Fan Habitat Restoration Concepts Report

Figure 2. Looking downstream (east) at Tillicum fan. Tillicum Creek along right edge. Mad River along far end of field.

Five soil pits were excavated on the Tillicum Fan on November 8, 2016 at locations shown on Figure 3. Soil profiles were documented by Inter‐Fluve staff and reported in a separate memorandum. Soils generally consist of fine soils of varying depths over gravel and cobble and are dry or have low rates of groundwater inflow. Perforated PVC piezometers with water level data loggers were installed in Pits 1 through 4. Data loggers will be downloaded in the spring of 2017.

March 2017 4 Tillicum Fan Habitat Restoration Concepts Report

Figure 3. Locations of 2016 soil pits

Soil types mapped by the USDA NRCS are fine loam in the valley (Figure 4). The two primary soil types in the Tillicum Fan project area include: #37 ‐ Billyridge gravelly sandy loam, which is a well‐drained soil that forms in alluvial fans; and, #33 ‐ Ardenvoir stony fine sandy loam which is a well‐drained soil that is generally formed by colluvium parent material from adjacent mountain slopes.

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Figure 4. NRCS soils types within the Tillicum fan area (USDA NRCS 2017).

GEOMORPHOLOGY The Tillicum Creek and fan is confined by valley wall along the south edge and Forest Road 5800 and valley wall along the north edge. The basal end of fan is about 700 feet upstream of the confluence with the Mad River. The distal end of the fan is the right bank of the Mad River. With few exceptions, riparian vegetation is robust along the banks of Tillicum Creek and the Mad River. The Tillicum fan surface is former pasture and currently fenced. Figures 2 and 3 provide an overview of site conditions.

Tillicum Creek average grade is 2.5% along the project reach. The creek is confined through entrenchment and periodic levees along the left bank. The right valley wall is in close proximity to the right bank with narrow 10 to 30‐foot wide flood prone benches between the creek and valley toe. Riparian vegetation is dense. The stream bed grade is partly controlled by colluvially derived lag material and woody debris that temporarily stores sediment. The stream banks are generally stable with vegetated banks along much of the project reach. Some banks have been stabilized with concrete rubble or stone armoring. Two locations vegetated by reed canary grass have undercut their banks and are migrating laterally.

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Occurrences of self‐formed channel sections and gravel bars are limited but do exist. Near the upstream end of the project reach, the creek has apparently hydrologically connected narrow vegetated flood benches (Figure 5). Approximately 80 feet upstream from the confluence with the Mad River is a gravel bar along the inside of a bend that provides a reference condition for future channel design. One pebble count was conducted along this self‐formed gravel bar indicative of developing OHW flood prone channel surface. Gradation of the sampled gravel bar material includes D16, D50, and D84 were 22mm, 64mm, and 128mm, respectively. Summary data are included in Appendix 1. Pebble count data will be used for channel design in future design phases.

Figure 5. Looking downstream along Tillicum Creek at typical self‐formed channel dimensions.

HYDROLOGY The Tillicum Creek watershed (Figure 1) encompasses approximately 22.25 square miles. It flows into the Mad River at approximately RM 1.9, which discharges to the Entiat River near the community of Ardenvoir. The Entiat River discharges to the Columbia River near Entiat, WA. Tillicum Creek watershed elevations range from about 1,400 feet up to about 5,700 feet. Mean annual precipitation in the basin is approximately 35 inches. Tillicum Creek has a snowmelt‐

March 2017 7 Tillicum Fan Habitat Restoration Concepts Report driven hydrograph with low flows in late summer and peak stream flows occurring during snow melt in spring and early summer. Runoff timing and duration are affected by ambient air temperatures, snowpack mass, and the distribution of the season’s snowpack.

No gage data exist for Tillicum Creek, and no flow measurement data on the creek were available for this study. A USGS gage exists on the Entiat River near Ardenvoir, but is of limited use for detailing Tillicum Creek hydrology. Thus, recurrence flows were calculated for Tillicum Creek using USGS regression equations (Mastin, 2016) and are summarized in Table 1. Calculations are included in Appendix 2.

Table 1. Flood recurrence flows for Tillicum Creek.

Recurrence Interval Peak Discharge (years) (cfs) 2 132 10 312 25 429 50 533 100 640

HYDRAULIC MODELING Existing channel and floodplain hydraulics were simulated using 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. The model was run in one‐dimensional steady state mode. Model results include estimates of flow depth, velocity, energy and extents of inundation for various flow conditions.

The model geometry for existing conditions cross sections were developed using topographic and bathymetry data obtained from the Inter‐Fluve survey completed in October 2016. Cross sections extend from Forest Service Road 5800, through the fan and channel to the south valley wall. The 2‐, 5‐, 10‐, 25‐, 50‐, and 100‐year recurrence interval floods summarized in Table 1 were modeled, as well as several flows less than the 2‐year event. Values for Manning’s n coefficient of hydraulic roughness were initially set at 0.07 for the floodplain and 0.040 for the channel based on professional judgement. The model was run in mixed mode to account for possible subcritical and supercritical flow conditions. Upstream and downstream boundary conditions were set at critical depth. Model results for existing conditions are included in Appendix 3.

Cross sectional geometries from survey data where self‐formed floodplain benches or gravel bars were present and HEC‐RAS inundations were used to estimate bank full flow to be

March 2017 8 Tillicum Fan Habitat Restoration Concepts Report approximately 80 cfs (~1.25‐year event). Corresponding average bank full channel cross section is 12 to 14ft wide by about 1ft deep. Proposed conditions were not modeled at this conceptual level and will be included as part of later phases of design.

The FEMA flood insurance rate map for Chelan County Washington (unincorporated areas), Community Panel 530015 0375A, effective date of February 4, 1981, indicates that the base flood delineation for the Mad River stops well short of the project area. Other than the NF 5800 road bridge at the upstream, northeast corner of the project area, the closest infrastructure to the project includes downstream residences with the closest being 0.9 miles downriver which includes a house with private bridge. Project impacts on Mad River hydraulic conditions will not extend downstream. 3. Preliminary Design Criteria A suite of preliminary design criteria are outlined below to guide development of concepts including: 1) Habitat, 2) Geomorphology/Hydrology, 3) Engineering and Risk, and 4) Construction Impacts.

Habitat  Promote natural habitat‐forming processes to the maximum extent practicable

 Increase floodplain inundation

 Increase in‐stream and floodplain habitat quality and quantity for steelhead and Chinook salmon rearing at a range of flows

 Design habitat elements that have low risk of creating fish passage barriers

Geomorphology/Hydrology  Design channels and floodplains that are consistent with current and projected hydrologic and geomorphic regimes

 Promote dynamic habitat‐forming processes

 Maintain sediment transport continuity to maximize design life and reduce in‐filling

 Promote sediment sorting

Engineering and Risk  Do not increase flooding or erosion risk to public or private infrastructure  Provide adequate ballasting of placed logs to withstand high flows that overtop the structures (i.e. compensate for buoyancy)  Minimize risk to river users. The only identified recreational use of Tillicum Creek and the Mad River is camping and day use along the floodplain and banks near the roads

March 2017 9 Tillicum Fan Habitat Restoration Concepts Report

Construction Impacts  Choose channel alignments that take advantage of gaps in riparian vegetation to protect existing mature vegetation.

 Minimize impacts to existing mature vegetation that is providing shade to Tillicum Creek and the Mad River

 Maximize shading of Tillicum Creek

4. Concept Designs This site is suitable for a project that provides enhanced floodplain connection and habitat complexity by excavating in the field area. New channel patterns can be formed on the alluvial fan to replicate fluvial signatures typical of dynamic fan and confluence processes.

The three enclosed concepts were developed to represent a range of restoration intensities and construction impacts. Each concept would create diverse and complex habitats through hydrologically connected floodplains and high flow channels, backwater areas and wetlands.

All three concepts leave Tillicum Creek in its current alignment and create a fan swale adjacent to the creek to increase flood prone riparian areas. Portions of bankfull and greater flows would access these areas, providing habitat opportunities while reducing hydraulic stress in the creek. The fan swale would be inset into a floodplain bench, and placement of woody debris would further improve habitat, geomorphic function, and natural aesthetic. The variation in terrain and seasonal contact with surface water and groundwater will support diverse wetland and riparian vegetation communities.

March 2017 10 Tillicum Fan Habitat Restoration Concepts Report

Alternatives one and two add a flood channel off the Mad River that would further increase habitat, diverse flow patterns, and wetland mosaic. High flows would seasonally pass along the upper portion of this new channel (cross section one), while the downstream portion would be backwatered by the Mad River (cross section two).

All concepts assume that fill generated from excavations will be placed on site as embankment along NF 5800 Road on site, contoured to blend into the surrounding landscape, and planted with upland trees and shrubs. The fill could be also be configured to reduce visibility of the project from the road and accessibility to recreational off road vehicles and snowmobiles.

Piezometer groundwater levels are currently being collected by water level data loggers and will be downloaded in the spring of 2017. Groundwater elevation information is anticipated to be useful for designing elevations that may be suited for wetlands and riparian plant communities. However, the November 2016 pump tests at Pit 1 indicates that inflow rate is very low, and other pits had insufficient inflow to warrant pump tests. Thus groundwater inflow is not anticipated to be adequate as a supply for flow along the new channel.

March 2017 11 Tillicum Fan Habitat Restoration Concepts Report

Concept 1: Fan Swale Extending to Mad River Concept 1 excavates a 600‐foot‐long fan swale roughly parallel to Tillicum Creek and extending to the right bank of the Mad River. Existing riparian vegetation will be protected to the degree possible to maintain shade along the creek and river. Large wood would be placed in areas expected to experience natural recruitment of wood. Ballasting designs will be completed at future phases with an emphasis on backfill and driven vertical logs as the primary restraint.

The new fan swale alignment would meet the Mad River at a location that minimizes disturbance to existing riparian vegetation. The Mad River will backwater into the new channel to various extents and depths depending on river levels. Piezometer water level logger data will be downloaded in the spring and evaluated in the next phase of work to evaluate groundwater levels and the possibility of creating wetlands and opportunities to intercept groundwater flow.

This is the smallest scale alternative in terms of earthwork volume, which is estimated to be 3,000 cubic yards (cy).

March 2017 12 Tillicum Fan Habitat Restoration Concepts Report

Concept 2: Short Fan Swale Extending to Mad River Relic Channel Concept 2 includes excavating a shorter length of fan swale through the existing field to enhance flood prone areas similar to Concept 1. This concept also includes a 375‐foot‐long excavation within the Mad River floodplain to emulate a relic channel of the Mad River that runs along the distal edge of the Tillicum fan. The upstream end of this relic channel would include a bar apex log structure to encourage portions of river flood flows to split into the relic channel, providing floodplain function and habitat. The upstream half of the relic channel is anticipated to be predominantly riparian wetland, with seasonal connection to groundwater and regularly flooding, while the lower extents would be backwatered by the river to various extents and depths depending on river stage.

This is the medium scale alternative, with less earthwork associated with the fan swale but more earthwork associated with Mad River floodplain enhancement. Volume is estimated to be 4,400 cy.

March 2017 13 Tillicum Fan Habitat Restoration Concepts Report

Concept 3: Long Fan Swale Extending to Mad River Relic Channel Concept 3 is the largest scale project that combines aspects of Concepts 1 and 2, creating a long fan swale that connects to a Mad River relic channel. This concept provides the greatest amount of habitat and complexity at a variety of flows, and the largest acreage of wetland creation. Earthwork volume is estimated to be 5,400 cy.

DESIGNER’S NOTES ON CONFIGURATIONS The concepts presented here are meant to show a suite of possibilities. Each of these concepts is scalable and can be combined or reconfigured into other schemes. The only limitation would be on the amount of fill that can be placed on site. If a significantly larger scale scheme is considered, offsite disposal of fill may be required.

The existing creek exhibits many attributes of good habitat, particularly during average and low flows. The riparian corridor is narrow, but it provides excellent shade canopy over the stream, and it is a source of small woody debris inputs and trapping. It was therefore decided to not

March 2017 14 Tillicum Fan Habitat Restoration Concepts Report include alternatives that re‐align the channel. Instead, the alternatives work with the existing creek by attaching adjacent flood prone areas that would relieve flood stress in the channel while also providing additional floodplain habitat and perennial backwater habitat. Furthermore, by not altering the existing channel, impacts to the fish and wildlife that occupy the stream are minimized, making environmental permitting easier, and significantly reducing fish exclusion and rescue efforts during construction.

Although the intent is to leave the existing channel in its current alignment, alluvial fans are naturally dynamic areas, so future sediment and debris loading, or beaver activity is expected to cause the configuration to evolve over time. 5. References Mastin, M.C., Konrad, C.P., Veilleux, A.G., and Tecca, A.E., 2016, Magnitude, frequency, and trends of floods at gaged and ungaged sites in Washington, based on data through water year 2014 (ver 1.1, October 2016): U.S. Geological Survey Scientific Investigations Report 2016‐5118, 70 p.

United States Geological Survey. 2016. StreamStats Program. Web. March 27 2016. .

Upper Columbia Regional Technical Team (UCRTT). 2014. A Biological strategy to protect and restore salmonid habitat in Upper Columbia Region (revised). A Report to the Upper Columbia Salmon Recovery Board from the Upper Columbia Regional Technical Team.

http://www.ucsrb.org/Assets/Documents/Library/REVISED%20Upper%20Columbia%20Rev ised%20Biological%20Strategy%202014%20(March%20).pdf

Upper Columbia Salmon Recovery Board (UCSRB). 2007. Upper Columbia salmon and Steelhead recovery plan: Upper Columbia Salmon Recovery Board, Wenatchee, Washington, 300 pp. .

USDA‐NRCS (United States Department of Agriculture – Natural Resources Conservation Service) National Cooperative Soil Survey. Official Soil Series Descriptions. Web. May 27, 2016. .

Washington State Dept. of Transportation (WSDOT). 2010. US2, XL 2793/4 Tumwater Canyon Bridge Replacements Geotechnical Report. Memorandum by B Romine. August 10, 2010.

Washington State Dept. of Transportation (WSDOT). 2014. WSDOT Fish Passage Performance Report. Environmental Services Office, Biology Branch, Stream Restoration Program. 184 pp.

March 2017 15 Tillicum Fan Habitat Restoration Concepts Report

Attachments

Tillicum Fan Habitat Restoration Concepts Report

‐ Grading plan and profile of alternatives

‐ Estimates

MAD RIVER

3,000 CY EXCAVATION 3,000 CY FILL

2+00 3+00

1+00

4+00 0+00 5+00

6+00

3+00 4+00 2+00

6+53 5+00 1+00 6+00 TILLICUM CREEK

7+00

0+00

8+00 9+00 9+30 PLAN 0 80 160

SCALE IN FEET GRADE BREAK STA = 6+44 ELEV = 103.0 GRADE BREAK STA = 3+69 ELEV = 94.2

100 100 GRADE BREAK STA = 0+13 3.2% ELEV = 85.8

90 90 2.4% 1 OF 3 CONCEPT 1 80 80 TILLICUM CREEK FAN CHANNEL C:\Users\danmiller\Documents\Client\Yakama Nation\Tillicum Fan\Drawings\References\Civil 3D\IFI_Tillicum-Fan_MPL-3-dm.dwg 6+53 6+00 5+00 4+00 3+00 2+00 1+00 0+00 TO MAD RIVER PROFILE MAD RIVER

4,400 CY EXCAVATION 4,400 CY FILL

3+00

2+00 4+00

1+00 5+00 3+00 4+005+34 2+00

5+00 1+00

6+00 TILLICUM CREEK 7+00 0+00

0+00

8+00 9+00 9+30 PLAN 0 80 160

SCALE IN FEET GRADE BREAK STA = 4+94 ELEV = 93.0 GRADE BREAK STA = 1+60 ELEV = 84.9 GRADE BREAK STA = 0+01 ELEV = 83.0

90 90 2.4%

1.2% 80 80 2 OF 3 5+34 5+00 4+00 3+00 2+00 1+00 0+00 CONCEPT 2 PROFILE TILLICUM CREEK FAN CHANNEL (SHORT) C:\Users\danmiller\Documents\Client\Yakama Nation\Tillicum Fan\Drawings\References\Civil 3D\IFI_Tillicum-Fan_MPL-3-dm.dwg AND MAD RIVER FLOODPLAIN ENHANCEMENT MAD RIVER

5,400 CY EXCAVATION 5,400 CY FILL

3+00

4+00 2+00

5+00 6+00

1+00 3+00 4+00 2+00 7+00 7+16 5+00 1+00

6+00 TILLICUM CREEK 7+00 0+00

0+00

8+00 9+00 9+30 PLAN 0 80 160

SCALE IN FEET GRADE BREAK STA = 7+02 ELEV = 103.0

110 110

100 100 GRADE BREAK STA = 1+63 ELEV = 84.9 GRADE BREAK STA = 0+15 ELEV = 83.2 3.4% 90 90 3 OF 3 1.1% CONCEPT 3 80 80 7+167+00 6+00 5+00 4+00 3+00 2+00 1+00 0+00 TILLICUM CREEK FAN CHANNEL (LONG) C:\Users\danmiller\Documents\Client\Yakama Nation\Tillicum Fan\Drawings\References\Civil 3D\IFI_Tillicum-Fan_MPL-3-dm.dwg PROFILE AND MAD RIVER FLOODPLAIN ENHANCEMENT Tillicum Fan Habitat Restoration Concepts Report

Appendix 1

Tillicum Fan Habitat Restoration Concepts Report

Pebble count

Tillicum Fan

Sediment Grain Size Analysis Gravel bar Identifier SUBSTRATE PHOTO 10/2/16 Date MM, MBr Personnel Tillicum Ck Stream 0.75 Approximate Depth of Flow at Thalweg (ft) gravel bar Longitudinal Description (Pool, Riffle, Bend, Crossing) surficial material Sample Type: Armor Layer or Subarmor

Notes: overview photo:

OVERVIEW PHOTO

Pebble Count Surficial Grain Size Analysis

24 100%

Pebble Count Data 22 Frequency 90% Class (Wentworth) Size Class mm Frequency Cumulative % 20 Cumulative % Sand <2 0 .0% 80% 18 Sand 2 3 3.4% 70% 16 Very Fine Gravel 2.1-4 0 3.4% 60% Fine Gravel 4.1-5.7 0 3.4% 14 Fine Gravel 5.8-8 0 3.4% 12 50% Medium Gravel 8.1-11.3 1 4.6% Frequency 10 40% Medium Gravel 11.4-16 5 10.3% 8 Coarse Gravel 16.1-22.6 2 12.6% 30% Coarse Gravel 22.7-32 6 19.5% 6 20% Very Course Gravel 32.1-45 6 26.4% 4 Very Course Gravel 45.1-64 13 41.4% 2 10%

Small Cobble 64.1-90 16 59.8% 0 0% 2

Small Cobble 90.1-128 21 83.9% <2 >256 2.1-4 5.8-8 4.1-5.7

Large Cobble 128.1-256 8 93.1% 11.4-16 22.7-32 32.1-45 45.1-64 64.1-90 8.1-11.3 90.1-128 16.1-22.6 Small Boulders >256 6 100.0% Median Axis Diameter (mm) 128.1-256 Total 87 Tillicum Fan Habitat Restoration Concepts Report

Appendix 2

Tillicum Fan Habitat Restoration Concepts Report

Hydrology

Flood Q Regression Tool. Use to estimate flood discharge in Washington State at ungaged sites based on regional regression equations and user-determined basin characteristics. DA = Drainage Area, in square miles; P = Average Basin Annual Precipitation, in inches (from PRISM data set, years 1981-2010); CAN = Percent canopy cover (NLCD 2001); AEP =

Annual Exceedance Probability; Qu = Flood Discharge, in cubic feet per second at ungaged site for the indicated AEP; PIL, PIU= Predition Intervals (L=Lower and U=Upper) Instructions for using the Flood Q Tool to estimate Flood Discharges at Ungaged Sites using the regional regression equations User determined basin characteristics for ungaged site Steps Instructions Selected Region: Regression Region 2 Range of values that are 1 Select the Regression Region below from the List Box valid for the regression Drainage Area, DA = 22.2 square miles 0.42 - 1820 2 Determine the drainage area, DA and the Annual Precipitation, P for the ungage drainage basin. If you pick Regression Region 1 or 2, determine the percent canopy cover, CAN . Annual Precipitation, P = 35.00 inches 8.86 - 84.20 Enter these basin characteristic values in the green-shade cells. If the cell changes to red, than 3 the value is outside the range of valid values for this regression. Valid value range listed to the Percent Canopy, CAN =50% 0.0 - 97.0 right of the green cells. Rows 23-30 will have the results. Estimated flood discharge, Qu, will be found in column O and 4 the 90% prediction limits for these flood discharges will be found in columns R and T. Selected Region: Regression Region 2 Estimate of indicated flood discharge for Regression Region 2 using regional regression equations Prediction Intervals, 90% confidence level 3 3 3 AEP *Qu, ft /sPIL, in ft /sPIU, in ft /s 0.5 = 132 43.6 399.7 0.2 = 231 82.8 644.1 0.1 = 312 106.4 914.8 0.04 = 429 132.4 1390.5 Regression Regions in Washington State 0.02 = 533 150.0 1894.4 0.01 = 640 165.2 2478.8 0.005 = 757 176.6 3244.7 0.002 = 930 191.8 4510.3

*rounded to 3 significant figures Tillicum Fan Habitat Restoration Concepts Report

Appendix 3

Tillicum Fan Habitat Restoration Concepts Report

HEC‐RAS hydraulic modeling – existing conditions

193.36

225.38 247.32

287.31

387.24 424.84 154.76

511.9 108.42 563.66 68.88 645.82

679.65 719.38

k C um l i c 32.93 T i l

Tillicum Ck Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Ck Tillicum Ck 115 Legend

WS 100yr WS 50yr

110 WS 25yr WS 10yr WS 5yr

WS 2yr

105 WS ~1.25yr WS ~1yr

WS 25cfs

WS 10cfs 100 Ground

LOB

ROB Elevation (ft) 95

90

85 485.43 511.9 563.66 596.82 613.21 645.82 679.65 719.38 57.67 68.88 108.42 154.76 193.36 225.38 247.32 287.31 359.85 387.24 424.84 80 0 100 200 300 400 500 600 700

Main Channel Distance (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 719.38 RS = 679.65 .07 .04 .07 .07 .04 .07 120 Legend 118 Legend

WS 100yr WS 100yr 118 116 WS 50yr WS 10yr 116 WS 25yr WS 50yr 114 WS 10yr WS 5yr 114 WS 5yr 112 WS 25yr 112 WS 2yr WS 2yr WS ~1.25yr 110 WS ~1.25yr Elevation (ft) Elevation (ft) 110 WS ~1yr WS ~1yr WS 25cfs 108 WS 25cfs 108 WS 10cfs WS 10cfs 106 Ground 106 Ground Bank Sta Bank Sta 104 104 0 20 40 60 80 100 120 0 20 40 60 80 100 120

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 645.82 RS = 613.21 .07 .04 .07 .07 .04 .07 118 Legend 116 Legend

WS 100yr WS 100yr 116 114 WS 50yr WS 50yr WS 25yr WS 25yr 114 112 WS 10yr WS 10yr 112 WS 5yr 110 WS 5yr WS 2yr WS 2yr 110 WS ~1.25yr 108 WS ~1.25yr

Elevation (ft) WS ~1yr Elevation (ft) WS ~1yr 108 WS 25cfs 106 WS 25cfs WS 10cfs WS 10cfs 106 Ground 104 Ground Bank Sta Bank Sta 104 102 0 20 40 60 80 100 120 140 160 0 20 40 60 80 100 120 140 160

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 596.82 RS = 563.66 .07 .04 .07 .07 .04 .07 116 Legend 114 Legend

WS 100yr WS 100yr 114 112 WS 50yr WS 50yr 112 WS 25yr WS 25yr 110 WS 10yr WS 10yr 110 WS 5yr 108 WS 5yr 108 WS 2yr WS 2yr WS ~1.25yr 106 WS ~1.25yr Elevation (ft) Elevation (ft) 106 WS ~1yr WS ~1yr WS 25cfs 104 WS 25cfs 104 WS 10cfs WS 10cfs 102 Ground 102 Ground Bank Sta Bank Sta 100 100 0 20 40 60 80 100 120 140 160 0 20 40 60 80 100 120 140 160 180

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 511.9 RS = 485.43 .07 .04 . .07 .04 . 112 0 Legend 110 0 Legend 7 7 WS 100yr WS 100yr 110 WS 50yr 108 WS 50yr WS 25yr WS 25yr 108 WS 10yr 106 WS 10yr 106 WS 5yr WS 5yr WS 2yr 104 WS 2yr 104 WS ~1.25yr WS ~1.25yr Elevation (ft) Elevation (ft) WS ~1yr 102 WS ~1yr 102 WS 25cfs WS 25cfs WS 10cfs WS 10cfs 100 100 Ground Ground Bank Sta Bank Sta 98 98 0 20 40 60 80 100 120 140 160 180 0 20 40 60 80 100 120 140 160 180

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 424.84 RS = 387.24 .07 .04 . .07 .04 . 108 0 Legend 106 0 Legend 7 7 WS 100yr WS 100yr 106 WS 50yr 104 WS 50yr WS 25yr WS 25yr 104 WS 10yr WS 10yr WS 5yr 102 WS 5yr 102 WS ~1yr WS 2yr WS 2yr WS ~1.25yr 100 Elevation (ft) Elevation (ft) 100 WS ~1.25yr WS ~1yr WS 25cfs WS 25cfs WS 10cfs 98 WS 10cfs 98 Ground Ground Bank Sta Bank Sta 96 96 0 50 100 150 200 0 50 100 150 200 250

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 359.85 RS = 287.31 .07 .04 .07 .07 . . 106 Legend 102 0 0 Legend 4 7 WS 100yr WS 100yr 104 WS 50yr 100 WS 50yr WS 25yr WS 25yr 102 WS 10yr 98 WS 10yr 100 WS 5yr WS 5yr WS 2yr 96 WS 2yr 98 WS ~1.25yr WS ~1.25yr Elevation (ft) Elevation (ft) WS ~1yr 94 WS ~1yr 96 WS 25cfs WS 25cfs WS 10cfs WS 10cfs 92 94 Ground Ground Bank Sta Bank Sta 92 90 0 50 100 150 200 250 0 50 100 150 200 250 300

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 247.32 RS = 225.38 .07 . .07 . 100 0 Legend 98 0 Legend 4 4 WS 100yr WS 100yr 98 WS 50yr 96 WS 50yr WS 25yr WS 25yr 96 WS 10yr WS 10yr WS 5yr 94 WS 5yr 94 WS 2yr WS 2yr WS ~1.25yr WS ~1.25yr 92 Elevation (ft) Elevation (ft) 92 WS ~1yr WS ~1yr WS 25cfs WS 25cfs WS 10cfs 90 WS 10cfs 90 Ground Ground Bank Sta Bank Sta 88 88 0 50 100 150 200 250 300 0 50 100 150 200 250 300

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 193.36 RS = 154.76 .07 . . .07 .04 .07 96 0 0 Legend 94 Legend 4 7 WS 100yr 93 WS 100yr 94 WS 50yr WS 50yr WS 25yr 92 WS 25yr WS 10yr WS 10yr 91 92 WS 5yr WS 5yr WS 2yr 90 WS 2yr WS ~1.25yr WS ~1.25yr 90 Elevation (ft) WS ~1yr Elevation (ft) 89 WS ~1yr WS 25cfs WS 25cfs 88 88 WS 10cfs WS 10cfs Ground 87 Ground Bank Sta Bank Sta 86 86 0 50 100 150 200 250 300 350 0 50 100 150 200

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 108.42 RS = 68.88 .07 . .07 .07 .04 .07 92 0 Legend 90 Legend 4 WS 100yr WS 100yr 91 WS 50yr 89 WS 50yr WS 25yr WS 25yr 90 WS 10yr 88 WS 10yr 89 WS 5yr WS 2yr WS 2yr 87 WS 5yr 88 WS ~1.25yr WS ~1.25yr Elevation (ft) Elevation (ft) WS ~1yr 86 WS ~1yr 87 WS 25cfs WS 25cfs WS 10cfs WS 10cfs 85 86 Ground Ground Bank Sta Bank Sta 85 84 0 50 100 150 200 0 20 40 60 80 100 120 140 160 180

Station (ft) Station (ft) Tillicum Fan Plan: TF-Existing 1/24/2017 Tillicum Fan Plan: TF-Existing 1/24/2017 RS = 57.67 RS = 32.93 .07 .04 .07 .07 .04 .07 90 Legend 88 Legend

WS 100yr WS 100yr 89 WS 50yr 87 WS 50yr WS 25yr WS 25yr 88 WS 10yr WS 10yr 86 87 WS 5yr WS 5yr WS 2yr WS 2yr 86 WS ~1.25yr WS ~1.25yr 85 Elevation (ft) WS ~1yr Elevation (ft) WS ~1yr 85 WS 25cfs WS 25cfs WS 10cfs 84 WS 10cfs 84 Ground Ground Bank Sta Bank Sta 83 83 0 50 100 150 200 0 5 10 15 20 25 30 35

Station (ft) Station (ft)

HEC-RAS Plan: Ex River: Tillicum Ck Reach: Tillicum Ck Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl Shear Chan (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (lb/sq ft) Tillicum Ck 719.38 10cfs 10.00 105.71 106.36 106.36 106.52 0.035216 3.26 3.06 9.47 1.01 0.70 Tillicum Ck 719.38 25cfs 25.00 105.71 106.63 106.63 106.89 0.030693 4.11 6.08 11.96 1.02 0.96 Tillicum Ck 719.38 ~1yr 55.00 105.71 107.03 107.00 107.40 0.023600 4.85 11.33 14.09 0.95 1.16 Tillicum Ck 719.38 ~1.25yr 80.00 105.71 107.28 107.24 107.73 0.022325 5.34 14.98 15.41 0.96 1.32 Tillicum Ck 719.38 2yr 132.00 105.71 107.63 107.63 108.27 0.023089 6.39 20.68 16.92 1.01 1.74 Tillicum Ck 719.38 5yr 231.00 105.71 108.21 108.21 109.10 0.019813 7.60 31.03 18.93 0.99 2.17 Tillicum Ck 719.38 10yr 312.00 105.71 108.63 108.63 109.68 0.017892 8.29 39.24 20.39 0.98 2.41 Tillicum Ck 719.38 25yr 429.00 105.71 109.28 109.28 110.37 0.013461 8.53 58.80 34.14 0.89 2.34 Tillicum Ck 719.38 50yr 533.00 105.71 109.71 109.71 110.86 0.012167 8.90 73.75 35.00 0.86 2.43 Tillicum Ck 719.38 100yr 640.00 105.71 110.02 110.02 111.31 0.012487 9.56 85.33 45.81 0.89 2.73

Tillicum Ck 679.65 10cfs 10.00 104.96 105.99 105.58 106.02 0.003716 1.48 6.74 12.09 0.35 0.12 Tillicum Ck 679.65 25cfs 25.00 104.96 106.38 105.92 106.45 0.004423 1.99 12.54 16.41 0.40 0.20 Tillicum Ck 679.65 ~1yr 55.00 104.96 106.80 106.92 0.005570 2.75 20.02 19.15 0.47 0.34 Tillicum Ck 679.65 ~1.25yr 80.00 104.96 107.03 107.20 0.006626 3.26 24.54 20.63 0.53 0.46 Tillicum Ck 679.65 2yr 132.00 104.96 107.39 106.90 107.66 0.007632 4.11 32.27 22.26 0.59 0.68 Tillicum Ck 679.65 5yr 231.00 104.96 107.91 107.42 108.35 0.008963 5.33 44.45 24.56 0.66 1.04 Tillicum Ck 679.65 10yr 312.00 104.96 108.20 107.79 108.80 0.010588 6.27 51.68 25.82 0.73 1.39 Tillicum Ck 679.65 25yr 429.00 104.96 107.83 108.23 109.48 0.035476 10.34 42.41 24.19 1.31 3.98 Tillicum Ck 679.65 50yr 533.00 104.96 108.12 108.62 110.02 0.034461 11.09 49.74 25.49 1.31 4.39 Tillicum Ck 679.65 100yr 640.00 104.96 108.45 108.94 110.48 0.031290 11.53 58.37 27.61 1.28 4.54

Tillicum Ck 645.82 10cfs 10.00 104.74 105.54 105.54 105.73 0.034428 3.46 2.89 7.95 1.01 0.76 Tillicum Ck 645.82 25cfs 25.00 104.74 105.87 105.87 106.11 0.031281 3.95 6.37 13.65 1.01 0.91 Tillicum Ck 645.82 ~1yr 55.00 104.74 106.22 106.22 106.53 0.030933 4.42 12.65 22.96 1.04 1.07 Tillicum Ck 645.82 ~1.25yr 80.00 104.74 106.39 106.39 106.77 0.027733 4.97 16.46 23.30 1.03 1.25 Tillicum Ck 645.82 2yr 132.00 104.74 106.68 106.68 107.20 0.024349 5.83 23.37 23.92 1.02 1.53 Tillicum Ck 645.82 5yr 231.00 104.74 107.18 107.18 107.89 0.019680 6.82 36.37 30.84 0.98 1.84 Tillicum Ck 645.82 10yr 312.00 104.74 107.54 107.54 108.33 0.016935 7.29 48.92 38.89 0.94 1.96 Tillicum Ck 645.82 25yr 429.00 104.74 107.91 107.91 108.86 0.016385 8.10 65.03 47.24 0.95 2.27 Tillicum Ck 645.82 50yr 533.00 104.74 108.47 108.47 109.21 0.010194 7.40 109.03 91.78 0.78 1.76 Tillicum Ck 645.82 100yr 640.00 104.74 108.54 108.71 109.50 0.013217 8.56 115.05 93.74 0.89 2.34

Tillicum Ck 613.21 10cfs 10.00 102.38 102.63 102.76 103.11 0.325161 5.56 1.80 13.31 2.67 2.73 Tillicum Ck 613.21 25cfs 25.00 102.38 102.73 102.96 103.65 0.313628 7.69 3.25 14.39 2.85 4.40 Tillicum Ck 613.21 ~1yr 55.00 102.38 102.91 103.25 104.23 0.233983 9.20 5.98 16.22 2.67 5.35 Tillicum Ck 613.21 ~1.25yr 80.00 102.38 103.02 103.44 104.65 0.220889 10.25 7.81 17.25 2.68 6.20 Tillicum Ck 613.21 2yr 132.00 102.38 103.22 103.78 105.33 0.178291 11.67 11.38 18.43 2.56 7.14 Tillicum Ck 613.21 5yr 231.00 102.38 103.55 104.33 106.33 0.136205 13.42 17.77 20.43 2.40 8.24 Tillicum Ck 613.21 10yr 312.00 102.38 103.79 104.68 106.94 0.115417 14.35 22.97 21.91 2.29 8.74 Tillicum Ck 613.21 25yr 429.00 102.38 104.15 105.13 107.57 0.090697 15.07 31.09 24.06 2.12 8.85 Tillicum Ck 613.21 50yr 533.00 102.38 104.40 105.49 108.18 0.083560 15.95 37.21 24.97 2.08 9.44 HEC-RAS Plan: Ex River: Tillicum Ck Reach: Tillicum Ck (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl Shear Chan (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (lb/sq ft) Tillicum Ck 613.21 100yr 640.00 102.38 104.74 105.83 108.42 0.065832 15.86 45.82 25.74 1.90 8.82

Tillicum Ck 596.82 10cfs 10.00 101.62 102.19 102.17 102.34 0.028710 3.05 3.28 9.62 0.92 0.60 Tillicum Ck 596.82 25cfs 25.00 101.62 102.45 102.45 102.72 0.029243 4.14 6.04 11.43 1.00 0.96 Tillicum Ck 596.82 ~1yr 55.00 101.62 102.88 102.88 103.19 0.029064 4.47 12.39 20.96 1.02 1.08 Tillicum Ck 596.82 ~1.25yr 80.00 101.62 102.96 103.05 103.47 0.040463 5.73 14.11 21.74 1.23 1.70 Tillicum Ck 596.82 2yr 132.00 101.62 103.27 103.37 103.90 0.030733 6.43 21.31 24.50 1.14 1.88 Tillicum Ck 596.82 5yr 231.00 101.62 103.52 103.89 104.72 0.043445 8.88 27.72 26.72 1.41 3.33 Tillicum Ck 596.82 10yr 312.00 101.62 103.70 104.21 105.33 0.049547 10.39 32.85 30.11 1.54 4.36 Tillicum Ck 596.82 25yr 429.00 101.62 103.94 104.59 106.09 0.053632 12.01 40.72 34.53 1.64 5.52 Tillicum Ck 596.82 50yr 533.00 101.62 104.11 104.90 106.73 0.058697 13.37 46.36 34.88 1.74 6.63 Tillicum Ck 596.82 100yr 640.00 101.62 104.31 105.17 107.21 0.057364 14.17 53.47 35.32 1.76 7.20

Tillicum Ck 563.66 10cfs 10.00 100.69 101.14 101.14 101.33 0.032632 3.47 2.92 7.90 1.00 0.76 Tillicum Ck 563.66 25cfs 25.00 100.69 101.47 101.48 101.72 0.031081 4.05 6.29 12.89 1.02 0.94 Tillicum Ck 563.66 ~1yr 55.00 100.69 101.80 101.84 102.17 0.032431 4.87 11.52 18.39 1.08 1.26 Tillicum Ck 563.66 ~1.25yr 80.00 100.69 101.97 102.05 102.44 0.035418 5.48 14.88 21.19 1.15 1.54 Tillicum Ck 563.66 2yr 132.00 100.69 102.30 102.37 102.84 0.031963 5.93 22.73 26.59 1.13 1.68 Tillicum Ck 563.66 5yr 231.00 100.69 102.87 102.78 103.44 0.018276 6.09 38.85 29.30 0.92 1.53 Tillicum Ck 563.66 10yr 312.00 100.69 103.25 103.07 103.88 0.014824 6.45 50.01 30.54 0.86 1.58 Tillicum Ck 563.66 25yr 429.00 100.69 103.80 103.45 104.48 0.010982 6.68 67.49 32.38 0.78 1.54 Tillicum Ck 563.66 50yr 533.00 100.69 104.22 103.75 104.96 0.009526 6.97 81.50 33.78 0.75 1.59 Tillicum Ck 563.66 100yr 640.00 100.69 104.64 104.06 105.43 0.008437 7.22 98.90 52.55 0.72 1.62

Tillicum Ck 511.9 10cfs 10.00 99.47 100.00 99.92 100.09 0.016805 2.39 4.18 11.88 0.71 0.37 Tillicum Ck 511.9 25cfs 25.00 99.47 100.27 100.17 100.44 0.017292 3.32 7.52 13.22 0.78 0.61 Tillicum Ck 511.9 ~1yr 55.00 99.47 100.65 100.52 100.94 0.016088 4.26 12.91 14.61 0.80 0.86 Tillicum Ck 511.9 ~1.25yr 80.00 99.47 100.91 100.75 101.26 0.015498 4.78 16.75 15.60 0.81 1.02 Tillicum Ck 511.9 2yr 132.00 99.47 101.34 101.15 101.82 0.014361 5.57 24.01 17.75 0.81 1.25 Tillicum Ck 511.9 5yr 231.00 99.47 102.01 101.76 102.66 0.012376 6.54 37.66 24.68 0.80 1.54 Tillicum Ck 511.9 10yr 312.00 99.47 102.48 102.19 103.22 0.010897 7.03 49.73 26.40 0.78 1.66 Tillicum Ck 511.9 25yr 429.00 99.47 103.13 102.67 103.95 0.009075 7.48 69.59 36.46 0.74 1.74 Tillicum Ck 511.9 50yr 533.00 99.47 103.43 103.13 104.43 0.009997 8.33 81.39 42.57 0.79 2.10 Tillicum Ck 511.9 100yr 640.00 99.47 103.57 103.57 104.86 0.012383 9.52 88.22 62.97 0.88 2.70

Tillicum Ck 485.43 10cfs 10.00 98.85 99.31 99.31 99.47 0.034599 3.21 3.13 9.98 1.00 0.69 Tillicum Ck 485.43 25cfs 25.00 98.85 99.58 99.58 99.86 0.028827 4.24 6.00 11.20 1.00 0.99 Tillicum Ck 485.43 ~1yr 55.00 98.85 99.97 99.97 100.40 0.024866 5.30 10.73 12.96 1.00 1.34 Tillicum Ck 485.43 ~1.25yr 80.00 98.85 100.23 100.23 100.76 0.023241 5.87 14.24 14.13 1.00 1.53 Tillicum Ck 485.43 2yr 132.00 98.85 100.66 100.66 101.36 0.020815 6.78 20.75 16.49 0.99 1.85 Tillicum Ck 485.43 5yr 231.00 98.85 101.32 101.32 102.26 0.017288 7.95 33.07 20.68 0.96 2.24 Tillicum Ck 485.43 10yr 312.00 98.85 101.79 101.79 102.85 0.015489 8.58 43.29 23.05 0.94 2.45 HEC-RAS Plan: Ex River: Tillicum Ck Reach: Tillicum Ck (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl Shear Chan (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (lb/sq ft) Tillicum Ck 485.43 25yr 429.00 98.85 102.23 102.23 103.59 0.016353 9.81 53.71 23.74 0.99 3.03 Tillicum Ck 485.43 50yr 533.00 98.85 103.15 103.15 104.18 0.009213 8.79 95.36 69.04 0.78 2.23 Tillicum Ck 485.43 100yr 640.00 98.85 103.49 103.64 104.55 0.008961 9.16 122.02 86.84 0.78 2.35

Tillicum Ck 424.84 10cfs 10.00 96.62 97.30 97.15 97.35 0.008164 1.83 5.52 14.04 0.51 0.20 Tillicum Ck 424.84 25cfs 25.00 96.62 97.58 97.37 97.69 0.008564 2.67 9.59 14.69 0.57 0.37 Tillicum Ck 424.84 ~1yr 55.00 96.62 97.95 97.69 98.17 0.009872 3.81 15.10 15.52 0.65 0.65 Tillicum Ck 424.84 ~1.25yr 80.00 96.62 97.66 97.92 98.56 0.060399 7.63 10.78 14.87 1.54 2.88 Tillicum Ck 424.84 2yr 132.00 96.62 97.92 98.31 99.27 0.061703 9.36 14.71 15.47 1.63 3.94 Tillicum Ck 424.84 5yr 231.00 96.62 98.34 99.00 100.36 0.059504 11.54 21.37 16.86 1.69 5.34 Tillicum Ck 424.84 10yr 312.00 96.62 98.65 99.45 101.09 0.056116 12.74 27.14 20.91 1.70 6.10 Tillicum Ck 424.84 25yr 429.00 96.62 99.06 99.99 101.84 0.049171 13.76 37.06 26.46 1.65 6.63 Tillicum Ck 424.84 50yr 533.00 96.62 99.23 100.39 102.78 0.057386 15.63 41.76 28.72 1.80 8.34 Tillicum Ck 424.84 100yr 640.00 96.62 99.55 100.69 103.19 0.051157 16.06 51.51 32.92 1.74 8.44

Tillicum Ck 387.24 10cfs 10.00 96.20 96.64 96.64 96.78 0.035268 3.00 3.34 11.88 0.99 0.62 Tillicum Ck 387.24 25cfs 25.00 96.20 96.89 96.89 97.13 0.029794 3.93 6.41 13.53 1.00 0.89 Tillicum Ck 387.24 ~1yr 55.00 96.20 97.21 97.21 97.58 0.026526 4.86 11.51 16.44 1.01 1.19 Tillicum Ck 387.24 ~1.25yr 80.00 96.20 97.42 97.42 97.88 0.024049 5.48 14.97 16.85 1.00 1.39 Tillicum Ck 387.24 2yr 132.00 96.20 97.78 97.78 98.42 0.021519 6.46 21.26 17.57 1.00 1.73 Tillicum Ck 387.24 5yr 231.00 96.20 98.44 98.44 99.27 0.016450 7.42 35.00 27.42 0.94 1.99 Tillicum Ck 387.24 10yr 312.00 96.20 98.80 98.90 99.79 0.016136 8.22 46.28 35.59 0.95 2.32 Tillicum Ck 387.24 25yr 429.00 96.20 99.22 99.42 100.39 0.015827 9.11 63.51 45.86 0.97 2.69 Tillicum Ck 387.24 50yr 533.00 96.20 99.31 99.79 100.95 0.021594 10.85 67.47 47.92 1.14 3.78 Tillicum Ck 387.24 100yr 640.00 96.20 99.51 100.07 101.40 0.023285 11.81 77.82 52.87 1.20 4.37

Tillicum Ck 359.85 10cfs 10.00 92.67 93.06 93.32 94.29 0.506398 8.88 1.13 5.73 3.53 6.15 Tillicum Ck 359.85 25cfs 25.00 92.67 93.24 93.61 94.97 0.424086 10.54 2.37 8.16 3.45 7.62 Tillicum Ck 359.85 ~1yr 55.00 92.67 93.48 93.96 95.66 0.327238 11.85 4.64 11.02 3.22 8.50 Tillicum Ck 359.85 ~1.25yr 80.00 92.67 93.62 94.20 96.11 0.294796 12.66 6.32 12.57 3.15 9.15 Tillicum Ck 359.85 2yr 132.00 92.67 93.87 94.59 96.84 0.224453 13.83 9.57 13.69 2.90 9.76 Tillicum Ck 359.85 5yr 231.00 92.67 94.25 95.17 97.94 0.176726 15.43 15.08 15.40 2.72 10.83 Tillicum Ck 359.85 10yr 312.00 92.67 94.54 95.60 98.51 0.143223 16.02 19.70 16.39 2.54 10.88 Tillicum Ck 359.85 25yr 429.00 92.67 94.94 96.08 99.19 0.105484 16.59 26.41 16.99 2.28 10.62 Tillicum Ck 359.85 50yr 533.00 92.67 95.30 96.69 99.66 0.082784 16.81 32.72 17.54 2.09 10.19 Tillicum Ck 359.85 100yr 640.00 92.67 95.66 97.14 100.14 0.068679 17.07 39.08 18.07 1.96 9.96

Tillicum Ck 287.31 10cfs 10.00 90.23 90.85 90.85 91.02 0.035435 3.28 3.05 9.37 1.02 0.71 Tillicum Ck 287.31 25cfs 25.00 90.23 91.14 91.14 91.40 0.030091 4.11 6.08 11.77 1.01 0.96 Tillicum Ck 287.31 ~1yr 55.00 90.23 91.51 91.52 91.90 0.026791 5.01 10.98 14.40 1.01 1.25 Tillicum Ck 287.31 ~1.25yr 80.00 90.23 91.75 91.75 92.22 0.025128 5.48 14.61 15.96 1.01 1.41 Tillicum Ck 287.31 2yr 132.00 90.23 92.13 92.13 92.75 0.022678 6.30 21.04 17.72 1.00 1.69 HEC-RAS Plan: Ex River: Tillicum Ck Reach: Tillicum Ck (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl Shear Chan (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (lb/sq ft) Tillicum Ck 287.31 5yr 231.00 90.23 92.63 92.69 93.57 0.022285 7.82 30.11 19.10 1.05 2.33 Tillicum Ck 287.31 10yr 312.00 90.23 92.92 93.09 94.17 0.024015 9.01 35.74 19.91 1.12 2.94 Tillicum Ck 287.31 25yr 429.00 90.23 93.25 93.61 94.96 0.026938 10.57 42.51 20.84 1.22 3.84 Tillicum Ck 287.31 50yr 533.00 90.23 93.50 94.01 95.63 0.029313 11.81 47.84 21.54 1.29 4.63 Tillicum Ck 287.31 100yr 640.00 90.23 93.72 94.40 96.29 0.031720 12.98 52.77 22.17 1.36 5.44

Tillicum Ck 247.32 10cfs 10.00 89.18 89.63 89.60 89.76 0.027244 2.88 3.47 10.64 0.89 0.55 Tillicum Ck 247.32 25cfs 25.00 89.18 89.89 89.87 90.13 0.025177 3.95 6.39 11.97 0.93 0.86 Tillicum Ck 247.32 ~1yr 55.00 89.18 90.15 90.23 90.68 0.035076 5.91 9.60 12.90 1.15 1.72 Tillicum Ck 247.32 ~1.25yr 80.00 89.18 90.37 90.49 91.05 0.033212 6.68 12.60 13.71 1.15 2.03 Tillicum Ck 247.32 2yr 132.00 89.18 90.78 90.93 91.68 0.030334 7.77 18.48 15.18 1.14 2.49 Tillicum Ck 247.32 5yr 231.00 89.18 91.47 91.62 92.61 0.025231 8.86 29.85 17.67 1.07 2.90 Tillicum Ck 247.32 10yr 312.00 89.18 91.95 92.09 93.23 0.023289 9.51 38.74 19.40 1.03 3.16 Tillicum Ck 247.32 25yr 429.00 89.18 92.64 92.67 93.99 0.019902 9.93 52.94 21.88 0.96 3.24 Tillicum Ck 247.32 50yr 533.00 89.18 93.08 93.15 94.58 0.020046 10.61 62.83 23.45 0.97 3.59 Tillicum Ck 247.32 100yr 640.00 89.18 93.48 93.56 95.13 0.020181 11.20 72.70 24.92 0.97 3.89

Tillicum Ck 225.38 10cfs 10.00 88.33 88.91 88.91 89.09 0.034052 3.40 2.94 8.13 1.00 0.74 Tillicum Ck 225.38 25cfs 25.00 88.33 89.23 89.23 89.52 0.030700 4.29 5.83 10.29 1.00 1.02 Tillicum Ck 225.38 ~1yr 55.00 88.33 89.54 89.63 90.07 0.040670 5.86 9.39 12.71 1.20 1.76 Tillicum Ck 225.38 ~1.25yr 80.00 88.33 89.83 89.87 90.41 0.029174 6.11 13.23 13.56 1.06 1.72 Tillicum Ck 225.38 2yr 132.00 88.33 90.25 90.30 91.03 0.026108 7.11 19.19 14.79 1.04 2.10 Tillicum Ck 225.38 5yr 231.00 88.33 90.77 91.00 92.00 0.029349 9.01 27.81 18.39 1.13 3.09 Tillicum Ck 225.38 10yr 312.00 88.33 91.14 91.45 92.63 0.029749 10.01 34.88 19.63 1.15 3.63 Tillicum Ck 225.38 25yr 429.00 88.33 91.62 92.02 93.40 0.029841 11.11 44.61 21.23 1.17 4.24 Tillicum Ck 225.38 50yr 533.00 88.33 92.02 92.45 93.99 0.029195 11.80 53.36 22.57 1.16 4.62 Tillicum Ck 225.38 100yr 640.00 88.33 92.39 92.87 94.54 0.028651 12.40 62.16 23.84 1.15 4.95

Tillicum Ck 193.36 10cfs 10.00 87.18 87.81 87.88 88.10 0.056597 4.36 2.29 6.46 1.29 1.22 Tillicum Ck 193.36 25cfs 25.00 87.18 88.27 88.22 88.53 0.023177 4.07 6.14 9.90 0.91 0.88 Tillicum Ck 193.36 ~1yr 55.00 87.18 88.59 88.65 89.11 0.030879 5.80 9.59 11.56 1.10 1.61 Tillicum Ck 193.36 ~1.25yr 80.00 87.18 88.85 88.93 89.48 0.028769 6.35 12.84 12.93 1.10 1.82 Tillicum Ck 193.36 2yr 132.00 87.18 89.21 89.37 90.11 0.030136 7.66 17.83 14.97 1.17 2.44 Tillicum Ck 193.36 5yr 231.00 87.18 89.77 90.05 91.07 0.027946 9.30 27.11 18.48 1.19 3.20 Tillicum Ck 193.36 10yr 312.00 87.18 90.14 90.53 91.72 0.026786 10.28 34.53 20.87 1.20 3.68 Tillicum Ck 193.36 25yr 429.00 87.18 90.61 91.10 92.51 0.025838 11.43 44.89 23.80 1.22 4.27 Tillicum Ck 193.36 50yr 533.00 87.18 90.97 91.56 93.11 0.025179 12.26 53.93 26.10 1.23 4.72 Tillicum Ck 193.36 100yr 640.00 87.18 91.30 91.92 93.67 0.024825 13.03 62.83 27.83 1.24 5.15

Tillicum Ck 154.76 10cfs 10.00 86.42 87.10 87.04 87.22 0.021265 2.73 3.67 10.17 0.80 0.47 Tillicum Ck 154.76 25cfs 25.00 86.42 87.36 87.32 87.59 0.024667 3.89 6.43 11.60 0.92 0.84 Tillicum Ck 154.76 ~1yr 55.00 86.42 87.70 87.70 88.11 0.026505 5.12 10.73 13.39 1.01 1.29 HEC-RAS Plan: Ex River: Tillicum Ck Reach: Tillicum Ck (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl Shear Chan (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (lb/sq ft) Tillicum Ck 154.76 ~1.25yr 80.00 86.42 87.90 87.94 88.45 0.028186 5.96 13.45 14.33 1.07 1.64 Tillicum Ck 154.76 2yr 132.00 86.42 88.32 88.35 89.02 0.023618 6.75 19.90 16.12 1.03 1.90 Tillicum Ck 154.76 5yr 231.00 86.42 88.77 88.99 89.93 0.028501 8.72 27.54 18.00 1.17 2.92 Tillicum Ck 154.76 10yr 312.00 86.42 89.06 89.48 90.57 0.030819 9.96 33.14 20.87 1.25 3.63 Tillicum Ck 154.76 25yr 429.00 86.42 89.44 90.04 91.38 0.031889 11.37 42.54 28.35 1.31 4.47 Tillicum Ck 154.76 50yr 533.00 86.42 89.72 90.46 91.98 0.032494 12.37 51.06 32.29 1.34 5.09 Tillicum Ck 154.76 100yr 640.00 86.42 89.97 90.77 92.53 0.033330 13.30 59.47 35.75 1.38 5.71

Tillicum Ck 108.42 10cfs 10.00 85.38 85.82 85.82 85.98 0.034734 3.20 3.12 9.82 1.00 0.68 Tillicum Ck 108.42 25cfs 25.00 85.38 86.09 86.09 86.36 0.028850 4.16 6.09 11.48 1.00 0.96 Tillicum Ck 108.42 ~1yr 55.00 85.38 86.46 86.46 86.90 0.026168 5.33 10.53 12.57 1.02 1.37 Tillicum Ck 108.42 ~1.25yr 80.00 85.38 86.70 86.71 87.26 0.023821 6.02 13.64 12.83 1.01 1.60 Tillicum Ck 108.42 2yr 132.00 85.38 87.08 87.14 87.92 0.024021 7.37 18.59 13.22 1.07 2.17 Tillicum Ck 108.42 5yr 231.00 85.38 87.84 87.88 88.93 0.018381 8.48 29.18 16.22 1.00 2.51 Tillicum Ck 108.42 10yr 312.00 85.38 88.49 88.64 89.56 0.013326 8.56 46.38 38.67 0.89 2.34 Tillicum Ck 108.42 25yr 429.00 85.38 88.82 89.14 90.23 0.015711 10.00 59.56 39.40 0.98 3.09 Tillicum Ck 108.42 50yr 533.00 85.38 89.08 89.49 90.74 0.017429 11.08 69.62 39.96 1.05 3.70 Tillicum Ck 108.42 100yr 640.00 85.38 89.31 89.79 91.22 0.018844 12.04 79.11 40.47 1.10 4.27

Tillicum Ck 68.88 10cfs 10.00 84.17 84.81 84.70 84.91 0.015442 2.60 3.91 9.26 0.70 0.41 Tillicum Ck 68.88 25cfs 25.00 84.17 85.16 85.01 85.34 0.013972 3.32 7.68 11.72 0.72 0.57 Tillicum Ck 68.88 ~1yr 55.00 84.17 85.69 85.41 85.92 0.010795 3.90 14.48 14.31 0.68 0.68 Tillicum Ck 68.88 ~1.25yr 80.00 84.17 85.96 85.67 86.27 0.010541 4.45 18.53 14.94 0.70 0.83 Tillicum Ck 68.88 2yr 132.00 84.17 86.37 86.07 86.84 0.011280 5.54 24.73 15.40 0.75 1.17 Tillicum Ck 68.88 5yr 231.00 84.17 86.32 86.70 87.86 0.038376 10.01 23.94 15.35 1.38 3.86 Tillicum Ck 68.88 10yr 312.00 84.17 86.62 87.11 88.62 0.039868 11.41 28.55 15.68 1.45 4.75 Tillicum Ck 68.88 25yr 429.00 84.17 87.28 88.02 89.34 0.027848 11.61 40.66 37.26 1.27 4.46 Tillicum Ck 68.88 50yr 533.00 84.17 87.63 88.50 89.85 0.026091 12.24 54.39 38.95 1.26 4.75 Tillicum Ck 68.88 100yr 640.00 84.17 87.92 88.88 90.31 0.025632 12.92 65.76 40.53 1.27 5.13

Tillicum Ck 57.67 10cfs 10.00 83.39 84.69 84.38 84.77 0.010049 2.23 4.62 9.51 0.57 0.29 Tillicum Ck 57.67 25cfs 25.00 83.39 85.04 85.20 0.010854 3.16 8.14 10.55 0.63 0.50 Tillicum Ck 57.67 ~1yr 55.00 83.39 85.53 85.79 0.012785 4.12 13.78 13.67 0.72 0.77 Tillicum Ck 57.67 ~1.25yr 80.00 83.39 85.81 86.14 0.012674 4.57 18.07 15.43 0.74 0.90 Tillicum Ck 57.67 2yr 132.00 83.39 86.23 86.71 0.012774 5.59 24.50 15.88 0.78 1.23 Tillicum Ck 57.67 5yr 231.00 83.39 86.69 86.57 87.57 0.016740 7.58 31.92 16.38 0.93 2.07 Tillicum Ck 57.67 10yr 312.00 83.39 87.27 87.27 88.18 0.012686 7.80 48.09 39.48 0.85 2.01 Tillicum Ck 57.67 25yr 429.00 83.39 87.32 87.85 88.95 0.022262 10.46 50.10 41.02 1.13 3.60 Tillicum Ck 57.67 50yr 533.00 83.39 87.54 88.15 89.50 0.024703 11.62 60.08 47.94 1.20 4.33 Tillicum Ck 57.67 100yr 640.00 83.39 88.90 88.48 89.55 0.006173 7.50 158.00 116.52 0.64 1.59

Tillicum Ck 32.93 10cfs 10.00 83.63 84.15 84.15 84.33 0.034784 3.43 2.92 8.14 1.01 0.76 HEC-RAS Plan: Ex River: Tillicum Ck Reach: Tillicum Ck (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl Shear Chan (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (lb/sq ft) Tillicum Ck 32.93 25cfs 25.00 83.63 84.46 84.46 84.76 0.029984 4.39 5.70 9.76 1.01 1.06 Tillicum Ck 32.93 ~1yr 55.00 83.63 84.89 84.89 85.33 0.025891 5.33 10.38 12.05 1.01 1.36 Tillicum Ck 32.93 ~1.25yr 80.00 83.63 85.15 85.15 85.69 0.024014 5.90 13.69 13.45 1.00 1.56 Tillicum Ck 32.93 2yr 132.00 83.63 85.62 85.62 86.30 0.018821 6.67 21.26 19.16 0.94 1.76 Tillicum Ck 32.93 5yr 231.00 83.63 86.29 86.29 87.16 0.015670 7.73 35.79 26.09 0.92 2.10 Tillicum Ck 32.93 10yr 312.00 83.63 86.50 86.75 87.75 0.020447 9.37 41.54 30.00 1.06 2.99 Tillicum Ck 32.93 25yr 429.00 83.63 87.00 87.27 88.38 0.018427 10.08 57.42 33.05 1.04 3.25 Tillicum Ck 32.93 50yr 533.00 83.63 87.35 87.61 88.85 0.017828 10.69 69.10 33.05 1.04 3.52 Tillicum Ck 32.93 100yr 640.00 83.63 87.92 87.92 89.27 0.013492 10.36 88.00 33.05 0.93 3.13