wa-ef1712303_HYD_5140(10.2)_AOP Report.pdf

Memorandum Western Federal Lands Highway Division

610 E. Fifth Street Vancouver, WA 98661-3801

OKANOGAN-WENATCHEE NATIONAL FORREST

FSR 5140 MP 10.2 AOP HYDRAULICS REPORT

To: Craig Sanders, WFLHD Project Manager From: Matthew Dillin, P.E., WFLHD Hydraulics Engineer Date: September 9, 2019 Project: FS Oka-Wen ERFO – WA FS EFRO 2017(1)-23(3)

Background

The Forest Service (FS) is replacing a failed culvert on forest service road (FSR) 5140 at mile post (MP) 10.2, Okanogan-Wenatchee National Forest, Okanogan County, Washington (Fig. 1). The Forest Service will maintain the new structure. Western Federal Lands Highway Division (WFLHD) is designing the replacement structure. Recommendations for the proposed aquatic organism passage (AOP) structure design are presented.

AOP Design Criteria

Forest Service biologists confirmed FSR 5140 MP 10.2 crossing requires an AOP structure (48°43’57.4”/-120°14’51.8”, NAD1983). The crossing is located on Ray Creek where a fish survey was conducted. During the survey cutthroat trout and brook trout were captured and positively identified upstream of the failed culvert. Constructing passable structures at this location will allow their passage to critical habitat.

Fish passage is required by Washington Administrative Code (WAC) 220-660-190, the Endangered Species Act (ESA), and the Magnuson-Stevens Fishery Conservation and Management Act. The recommended fish passage crossing design is consistent with requirements of the Aquatic Restoration Biological Opinion II (ARBOII).

The proposed AOP structure has been designed per Stream Simulation: An Ecological Approach to Providing Passage for Aquatic Organisms at Road-Stream Crossings (USDA-Forest Service 2008). This method provides a simplified design methodology that is intended to mimic natural upstream and downstream processes within the culvert. Fish passage, sediment transport, and debris conveyance within the culvert are designed to function as they would in the adjacent natural channel. Determination of the high and low fish passage design flows, water velocity, and water depth is not required for this method since the stream hydraulic characteristics within the culvert are intended to mimic the stream conditions upstream and downstream of the crossing. The method utilizes streambed materials that are like the adjacent channel, providing similar channel complexity, flow depth, flow velocities, and resting areas.

The following requirements have been incorporated into the AOP design:

Flood Conveyance: Culvert capacity exceeds the 100-year (70 cfs) recurrence flood without roadway overtopping.

Culvert Width: Must accommodate the design channel bankfull width plus additional width for construction of stable bank rocks along both sides of the channel inside the culvert. The minimum culvert

Memo to: Craig Sanders, WFLHD Project Manager September 2019 bed width is 1.3 times the bankfull channel width for non-entrenched streams. For entrenched streams (entrenchment ratio < 1.4) the minimum width is bankfull channel width plus room for natural channel banks.

Channel Vertical Clearance: Clearance from bed to ceiling must be at least 5.9 feet to allow for ease of construction, maintenance, and debris removal.

Channel Slope: Reconstructed streambed within the culvert should approximate the average slope of the adjacent stream from approximately ten channel widths upstream and downstream of the culvert site, and should not deviate by more than 1%.

Embedment: Bottom of the culverts should be buried into the streambed between 30 and 50 percent of the culvert height, and a minimum of 3 feet.

Maximum Length of Road Crossing: Length should be less than 150 feet.

Fill Materials: Fill materials are comprised of material similar in size composition to natural bed materials that form the natural stream channels adjacent to the road crossing. Larger material is added for assisting stream gradient retention and providing resting areas for migrating fish.

Water Depth and Velocity: Water depth and velocity in the culvert must closely resemble those existing in the adjacent stream.

FSR 5140 MP 10.2 AOP Culvert

Ray Creek is a tributary to Falls Creek and ultimately the Chewuch River. The stream currently crosses Forest Road (FSR) 5140 by overtopping the roadway approximately 0.5 miles upstream of its confluence with Falls Creek. The current crossing is located within a natural depositional area, as the stream transitions to a shallow gradient from a steeper gradient upstream. This natural stream process has been exacerbated by the influence of a fire in 2014 within the watershed.

Heavy rains during the winter of 2017 resulted in the mobilization of a large sediment and debris pulse upstream of the project reach. High flows carried the material downstream where they were deposited at the crossing, causing the channel to aggrade and bury the existing 48” culvert. During the event, flows overtopped the road and washed out some of the roadway embankment material. The new channel currently flows over the roadway before entering the downstream channel.

Due to the recent fire and the large mobilization of sediment, streambanks are poorly defined near the crossing. Upstream and downstream of the crossing the stream is in the process of downcutting into the newly deposited material. Very little references remain for accurate measurements of bankfull widths near the crossing. Vegetation and bank features which remained intact further downstream of the crossing (Appendix, photo 7) suggest that the natural bankfull width is roughly 6-feet to 7-feet with a channel slope around 5.4 percent and a channel depth of approximately 18 inches. These values were supported by additional measurements taken upstream of the crossing where the bankfull width was found to be roughly 6 feet with channel slope around 9.4 percent. Step-pools and cascades are the controlling bedforms. Boulder, cobble, and gravel is the dominant bed material. Streambed gradation was measured by digital pebble count using FHWA Hydraulic Toolbox, version 4.3, and processing digital-scaled photographs at seven stream locations. Resulting gradation is D100 10 inches, D85 6 inches, D50 3.5 inches, and D15 1.6 inches (Fig.3).

Based on observed post flood conditions, the stream can likely carry a significant amount of small to moderate sized woody debris. Stream flow when fish passage is needed will be low. Smaller flows could submerge within the natural channel where larger loose material has been deposited. To avoid creation of

September 2019 similar low flow subsurface conditions, material placed within the proposed culvert and outlet will need to avoid excessive amounts of oversized loose bed material or large stone. Continued cycles of aggradation/degradation should be expected as the stream deposits sediment, erodes, reforms its natural bankfull channel, and transports material from upstream. Additional debris flows during large flood events can be expected due to geomorphic landscape and large amount of unvegetated loose deposited material remaining upstream from the site.

Recommendations:

• Install new culvert on existing stream alignment.

• Install a 68-foot long, corrugated metal culvert with an 12-foot diameter (Preliminary Sheet F.4).

• To maximize capacity for flow and debris conveyance and accommodate channel aggradation, set new culvert crown as high in the road prism as possible.

• Place culvert floor at elevation 4705.3 feet upstream and at elevation 4702.6 feet downstream (project datum).

• Maximizing clearance for debris passage and maintenance access while economizing culvert size by installing culvert at a 4.0 percent grade.

• Place conserved streambed material inside the culvert matching the gradation of the natural streambed material.

• Slope the channel surface to match immediate downstream gradient (5.4 percent).

• Construct a defined flow channel 7 feet wide at the bottom and 18 inches deep (Preliminary Sheet F.11).

• Construct the flow channel banks from coarser gravel, cobble, and boulder material.

• Install 17 boulders, approximately 24 inches in diameter, as shown on Preliminary Sheet F.11 for inducing channel migration and providing low velocity fish resting areas.

• Install Class 3 riprap (FHWA FP-14), minimum 3 feet thick, at the inlet and outlet for controlling road embankment erosion near the culvert (Preliminary Sheet F.10).

• Install Class 1-C nonwoven geotextile (FHWA FP-14) under the riprap.

• Shape new channel approximately 30 lineal feet immediately upstream and 30 lineal feet immediately downstream for aligning the culvert channel with the natural channel.

• Seed and plant any disturbed areas with local native vegetation.

Construction

The Washington Department of Fish and Wildlife instream work period is July 1 to July 31. Temporary flow deflectors placed for isolating the work area and diverting the stream flow must have a minimum height of 3 feet above the stream bottom and be stable assuming 8 feet per second parallel flow and 2 feet maximum water depth. Use plastic-lined channels or pipes for temporally conveying stream flow through the construction area. Protect the outfalls from erosion. Fish passage downstream through the temporary flow diversions is required. Ensure fish can pass smoothly from the upstream diversion point to the downstream diversion point. Locate diversion points in the main stream channel. Fish passage upstream is not required. Temporary stream diversions in place must have minimum flow capacity equal to the 2-year discharge (20 cfs). Before installing the flow deflectors, remove fish from the work area to the level and methods specified in the environmental permits.

Vehicular traffic will not be maintained through the work site. Full construction area dewatering is expected up to the groundwater level for excavation and installing the culvert, streambed material, September 2019 backfill, and riprap. Water pumped from work area must be discharged at an upland area near the site.

Access for culvert installation work can be accomplished within the existing road embankment footprint.

Temporary access route adjacent to the road embankment is needed for installing flow barriers, removing the channel debris, and completing culvert inlet, interior, and outlet work. Constructing the proposed culvert and in-stream work may require heavy track-mounted equipment operating on the stream bed, possibly in water up to 2 feet deep.

The State of Washington and the U.S. Fish and Wildlife Service will restrict the release of turbidity from the work areas into the stream. The agencies require turbidity control and monitoring, and should be contacted for specific requirements and allowable discharge limits.

Stream Impacts

The proposed fish passage culvert is expected to dramatically improve stream flow conveyance, sediment transport, and woody debris transport to a level that is similar for adjacent natural streams. Both channel degradation and aggradation is expected upstream, inside, and downstream of the proposed fish passage culvert.

A moderate amount of turbidity and sediment is expected to be released when the flow barriers are removed and stream flow is introduced into the newly constructed culvert. The amount of turbidity and sediment will be reduced by removing the flow barriers gradually introducing the stream flow over an extended two to three-hour time.

Operation and Maintenance

Woody debris will tend to accumulate more frequently at the culvert inlet and inside the culvert barrel.

The FS should increase the frequency of culvert inspection and woody debris removal. Stream degradation is not expected to negatively impact culvert structure or performance. Stream aggradation could reduce the culvert hydraulic capacity. Remove sediment from the upstream channel, inside the culvert, the downstream channel when there is less than 5 feet of clearance between the stream bottom and culvert crown at the inlet. Riprap placed at the culvert inlet and outlet should be inspected annually and after each extreme flood event. Replace or reposition dislodged stone.

Floodplain and Flood-rise Impacts

Flood limits and elevations have not been mapped by the National Flood Insurance Program for the site.

The proposed culverts will improve hydraulic conveyance and is not expected to negatively impact flooding at the site.

Hydrology

The USGS StreamStats (version 4) web-based application was used for delineating the watershed and calculating drainage area (2.25 sq. miles), canopy cover (63 percent), and mean annual precipitation (36.8 inches). Peak discharges were estimated with StreamStats using USGS regression equations from Magnitude and Frequency of Floods in Washington (USGS WRIR 97-4277). Watershed is entirely within Region 2 for the USGS regression equations. The watershed is mostly forested (Fig. 2). Fires and logging have occurred within the watershed and can occur in the future. No flow diversions or lakes occur. The drainage area is mountainous with moderately incised drainages. Area with slopes greater than 30 percent is 84 percent. Elevations range from 4710 to 7410 feet (NAD83/WGS84). A summary of peak discharges and their corresponding water depths at the culvert inlet are presented in Table 1.

September 2019

Dominant flooding is from snow melt. Larger floods typically occur in April, May, June, and July. Rain-on-snow flood events can occur in October, November, and December. Lowest flows occur in August and September.

Culvert Hydraulics

Water surface profiles and culvert capacities were estimated using the FHWA Culvert Hydraulics Analysis Program, HY-8, version 7.5 (results attached). Floods larger than the 2-year were analyzed assuming culvert slope of 5.4 percent and Manning’s Roughness coefficient of 0.051 for the channel bottom and 0.024 for the culvert sides and top. Headwater depths are shown on Table 1.

Flow depths and average channel velocities inside the proposed culverts for up to the 2-year peak discharge were estimated with the FHWA Hydraulic Toolbox, version 4.3, open-channel flow calculator.

The calculations assumed 7 feet channel bottom width, 1:1 sides, and 5.4 percent channel slope. The Manning’s Roughness coefficient was iterated using the Blodgett Equation for the 2-year discharge. This equation calculates the Manning’s Roughness coefficient as a function of flow depth and median stone size. A Manning’s Roughness coefficient of 0.062 was calculated. Average channel flow velocities inside the culverts are presented in Figure 4.

Attachments: Table 1 – Peak Discharges and Water Depths Figures 1, 2, 3, and 4 Photographs 1 to 9 Preliminary SheetsF.4, F.10, and F.11 Peak Discharge Estimates HY-8 Calculations Hydraulic Toolbox Calculations Channel Profile

Drainage

Site Area (mi²) 2 5 10 25 50 100 500

Culvert Peak Q (cfs) 2.25 20 NA 40 50 60 70 NA

Water Elev. at Inlet (ft) 4,711.8 NA 4,712.2 4,712.3 4,712.5 4,712.7 NA

Clearance at Inlet (ft) 5.5 NA 5.1 5.0 4.8 4.7 NA

Water Depth at Inlet (ft) 0.4 NA 0.8 0.9 1.1 1.3 NA

Notes:

1. USGS - USGS Regression Equations, “Magnitude and Frequency of Floods in Washington”, WRIR 97-4277, 1998.

NA = Not analyzed.

Table 1. Peak Discharges (ft3/sec) and Water Depths at Inlets

Recurrence Intervals (years)

Image date: 7/14/2017

Project AOP Culvert Site Location

Project Area Location

USGS Topographic Maps on Google Earth

N

FIGURE 1

FSR 5140 MP 10.2

AOP CULVERT

SITE LOCATION

MP 10.2

1000 feet0

Map printed from Google Earth, Image date 7/14/2017.

N

DA = 2.25 sq. mi.

FIGURE 2

FSR 5140 MP 10.2

AOP CULVERT

DRAINAGE AREA

0 5000 feet

FIGURE 3

FSR 5140 MP 10.2

AOP CULVERT

STREAMBED GRADATION

FIGURE 4

AOP CULVERT

2-YEAR FLOW VELOCITY

Photos

PHOTO 1

PHOTO 2

PHOTO 3

12/1/2018

FSR 5140 MP 10.2

The channel currently travels over the roadway as the existing culvert is burried.

Existing cuvlert outlet almost completely burried.

Channel over roadway.

Culvert Inlet.

Existing culvert inlet completely burried with sediment.

Culvert outlet.

PHOTO 4

PHOTO 5

PHOTO 6

12/1/2018

Channel downstream of culvert. Looking upstream at roadway.

Channel cutting a new alignment downstream of the culvert. Lots of debris deposited in channel.

Debri in channel downstream of crossing.

FSR 5140 MP 10.2

Example of debri deposited in channel downstream of crossing.

Channel over roadway looking downstream.

The channel currently travels over the roadway as the existing culvert is burried.

PHOTO 7

PHOTO 8

PHOTO 9

12/1/2018

Bankfull width measured roughly 300 feet downstream of the existing crossing.

Bankfull width measured roughly 400 feet upstream of crossing.

Due to deposition of sediment and debris from recent event, very little references remained for accurate measurements of bankfull widths. Vegetation which remained at this location suggests a bankfull width of roughly 6 feet to 7 feet with an approximate slope of 5%.

Looking north at upstream channel roughly 300 feet from crossing. Due to instability in the reach from fires in the watershed, very little references remained for accurate measurements of bankfull widths. Vegetation which remained at this location suggests a bankfull width of roughly 6 feet with an approximate slope of 9%.

Channel upstream of crossing.

Picture of channel less than 100 feet upstream of crossing. Bankfull measurement in this reach was approximately 6 feet.

50 30 2040 10 0 10 20 30 40 5060 60

FISH SPECIES:

HYDRAULIC INFORMATION

FLOWLINE SLOPE:

OUTLETINLETPIPE

INV N/E/EL:

BURIAL DEPTH:

LOWER BEVEL HEIGHT:

BEVEL:

HEADWALL:

INV N/E/EL:

BURIAL DEPTH:

LOWER BEVEL HEIGHT:

BEVEL:

HEADWALL:

RISE:

WALL THICKNESS:

TYPE:

LENGTH:

SPAN:

PIPE SLOPE:

OHW:

HW :

Q :

Q :

INFILL TYPE: TYPE:

F.4

STATE PROJECT

NUMBER

SHEET

WA

FS ERFO 2017(1)-23(3)

D A

T E

P

A T

H

C h e c k e d b y

D e s ig n e d b y

Corrugated Metal Pipe

Corrugated Metal Pipe Corrugated Metal Pipe

68 ft

AOP

6.1 ft

Riprap Riprap

5.2 ft

NA

N

0.054 ft/ft

100 100

1V : 2H

12 ft 12 ft

0.04 ft/ft

3 ft 3 ft

PLAN AND PROFILE

AOP CULVERT

FSR 5140 MP 10.220 cfs

70 cfs 1.3 ft

0.7 ft

1V : 2H

632584.6/1781764.0/4705.3 632594.8/1781696.6/4702.6

Scale in feet

5 2.5 0 5 10 15 20

LC

boulder per detail Sheet F.11 material and fish passage Backfill with streambed elev. 4707.8' Prop. channel

Existing ground

Remove existing 24" CMP

Flow

Flow

Slope 5.4% elev. 4702.6' DS invert m in m in

Slope 4.0% debris in channel Remove existing

100yr WSE elev. 4711.4' Prop. channel see sheet F.10 for details (riprap end treatment) method A, class 4 Place riprap see sheet F.10 for details (riprap end treatment) method A, class 4 Place riprap road centerline

144-inch pipe culvert see sheet F.10 for details (riprap end treatment) method A, class 4 Placed riprap see sheet F.10 for details (riprap end treatment) method A, class 4 Placed riprap elev. 4705.3' downstream invert

Traveled WayPRELIM

IN

ARY

NOT FOR C

ONSTRUCTIO

F.10 WA FS ERFO 2017(1)-23(3)

DETAILS

RIPRAP HEADWALL

STATE PROJECT

NUMBER

SHEET

S

L e o n

J

N e ig h o r n

C h e c k e d b y

D e s ig n e d b y

U

S S u r ft

D c p w w o r k d w a e f1 e k .d g n

P

M

A u g u s t

NOTE:

FOOTNOTE:

shown on site specific details, whichever is greater.

Construct riprap end treatment to a thickness of 36-inches or as[3]

Riprap end treatment slope to match roadway embankment slope.[2]

Bevel to match roadway embankment.[1]

Sl op e

PIPE BEVEL DETAIL

Sl op e

SKEW ANGLE DIAGRAM

c e n te r li n e

R o a d w a y

Cu lv er t ce nt er lin e

BOP

EOP

(DIAMETER OR SPAN GREATER OR EQUAL TO 48-INCHES)

(DIAMETER OR SPAN LESS THAN 48-INCHES)

.2

D o r R

.2

D o r R o r R is e

R

D ia m e te r

D o r R is e

R

D ia m e te r

D

W

RIPRAP END TREATMENT

Sl op e

FRONT VIEW SIDE VIEW

24" shown in the plans

Streambed material where shown in the plans

Streambed material where

V a r ia b le R is e

W2

Variable W2

V a r ia b le R is e

[1]

[1]

Manufacturer's standards

0.25 D or R or per the

Optional

Skew

Placed riprap

Placed riprap

NO SCALE

geotextile filter, class 1, type C

Place earthwork geotextile between riprap and soil.

Contractor to field verify all invert elevations, prior to installation.

2.

1.

[3

" m in

[2

PRELIM

IN

ARY

NOT FOR C

NO SCALE

PLAN

F lo w

A A

B

B

NOTE:

FOOTNOTE:

3.

2.

1.

Stagger in-channel fish passage boulder within the culvert span.

streambed cobble, and bank stone gradations.

See special contract requirements for streambed sediment, Mix streambed cobbles evenly throughout streambed sediment.

[1]

TREATMENT

CULVERT INTERIOR

SIMULATED STREAM

F.11

STATE PROJECT

NUMBER

SHEET

U

S I n t2

D c p w w o r k d w a e f1 e l.

d g n

WA FS ERFO 2017(1)-23(3)

P

M

A u g u s t

C h e c k e d b y

D e s ig n e d b y

18-inches or as specified on plan sheet.[4] dimension.

smallest4 3 Embed fish passage boulders within active channel [3] streambed sediment.

Construct well defined banks with bank stone and[2] parabolic shape. Include meandering depressed low-flow.

Slope streambed aggregate towards flowline to ensure[1]

SECTION A-A

Flow

D2

SECTION B-B

LC

D

D ty p

D ty p

(typ.)

(typ.)

36" min.

or Length on plan sheet

W

Streambed sediment

Streambed cobble

Pipe arch culvert wall

Box culvert wall boulder

Fish passage boulder

Fish passage

[3]Fish passage boulder

[2]Bank stone

[2]Bank stones d e p th b u r ia l b u r ia l d e p th

Round pipe culvert wall top

Streambed

Culvert outlet

Culvert wall sediment

Streambed

Culvert inlet

Streambed cobble

Streambed sediment

Channel flowline depressed low-flow

Channel flowline with low-flow through culvert

Meander depressed

PRELIM

IN

ARY

NOT FOR C

StreamStats Report

Basin Characteristics

Parameter Code Parameter Description Value Unit

DRNAREA Area that drains to a point on a stream 2.25 square miles

PRECPRIS10 Basin average mean annual precipitation for 1981 to 2010 from PRISM 36.8 inches

CANOPY_PCT Percentage of drainage area covered by canopy as described in OK SIR 2009_5267 63.3 percent

Peak-Flow Statistics Parameters [Peak Region 2 2016 5118]

Parameter Code Parameter Name Value Units Min Limit Max Limit

DRNAREA Drainage Area 2.25 square miles 0.42 1330

PRECPRIS10 Mean Annual Precip PRISM 1981 2010 36.8 inches 8.86 84.2

CANOPY_PCT Percent Area Under Canopy 63.3 percent 0 81.8

Peak-Flow Statistics Flow Report [Peak Region 2 2016 5118]

PIl : Prediction Interval-Lower, PIu: Prediction Interval-Upper, SEp: Standard Error of Prediction, SE: Standard Error (other - - see report)

Statistic Value Unit PIl PIu SEp

2 Year Peak Flood 18.8 ft^3/s 6.1 57.7 77.2

5 Year Peak Flood 29.2 ft^3/s 10.5 81.5 69.1

10 Year Peak Flood 37.7 ft^3/s 13 109 72.2

25 Year Peak Flood 49.2 ft^3/s 15.3 159 81.2

50 Year Peak Flood 59.5 ft^3/s 16.9 210 89.2

100 Year Peak Flood 69.6 ft^3/s 18.2 267 96.9

200 Year Peak Flood 79.4 ft^3/s 18.9 333 106

500 Year Peak Flood 96 ft^3/s 20.3 454 120

Region ID: WA Workspace ID: WA20180917180234431000 Clicked Point (Latitude, Longitude): 48.73172, -120.24757 Time: 2018-09-17 11:02:50 -0700

HY-8 Culvert Analysis Report

Table 2 - Culvert Summary Table: 12' CMP @5%

* Full Flow Headwater elevation is below inlet invert.

Straight Culvert

Inlet Elevation (invert): 4711.40 ft, Outlet Elevation (invert): 4707.80 ft

Culvert Length: 68.10 ft, Culvert Slope: 0.0529

Culvert Data Summary - 12' CMP @5% Barrel Shape: Circular

Barrel Diameter: 12.00 ft Barrel Material: Corrugated Steel

Embedment: 73.20 in Barrel Manning's n: 0.0240 (top and sides)

Manning's n: 0.0510 (bottom) Culvert Type: Straight

Inlet Configuration: Mitered to Conform to Slope Inlet Depression: None

Discharge Names

Total Discharge

(cfs) Culvert

Discharge (cfs)

Headwater Elevation

(ft) Inlet

Control Depth (ft)

Outlet Control

Depth (ft) Flow Type Normal

Depth (ft) Critical Depth (ft) Outlet

Depth (ft) Tailwater Depth (ft)

Outlet Velocity

(ft/s) Tailwater Velocity

(ft/s) 2yr 20.00 20.00 4711.83 0.426 0.0* 1-S2n 0.428 0.440 0.428 0.602 3.856 4.370 10yr 40.00 40.00 4712.17 0.774 0.0* 1-S2n 0.653 0.701 0.653 0.911 5.052 5.550 25yr 50.00 50.00 4712.34 0.938 0.0* 1-S2n 0.750 0.812 0.750 1.040 5.495 5.977 50yr 60.00 60.00 4712.50 1.096 0.0* 1-S2n 0.837 0.922 0.837 1.159 5.911 6.345 100yr 70.00 70.00 4712.65 1.247 0.0* 1-S2n 0.921 1.020 0.921 1.269 6.264 6.668

Table 3 - Downstream Channel Rating Curve (Crossing: 5140-10.2 Culvert (Copy))

Tailwater Channel Data - 5140-10.2 Culvert (Copy) Tailwater Channel Option: Trapezoidal Channel

Bottom Width: 7.00 ft Side Slope (H:V): 1.00 (_:1)

Channel Slope: 0.0530 Channel Manning's n: 0.0510

Channel Invert Elevation: 4707.80 ft

Roadway Data for Crossing: 5140-10.2 Culvert (Copy) Roadway Profile Shape: Constant Roadway Elevation Crest Length: 50.00 ft

Crest Elevation: 4718.00 ft Roadway Surface: Gravel

Roadway Top Width: 14.00 ft

Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number

20.00 4708.40 0.60 4.37 1.99 1.03

40.00 4708.71 0.91 5.55 3.01 1.08

50.00 4708.84 1.04 5.98 3.44 1.10

60.00 4708.96 1.16 6.35 3.83 1.11

70.00 4709.07 1.27 6.67 4.20 1.12

Hydraulic Analysis Report Project Data Project Title: 5140(10.2) AOP Designer: MFD

Project Date: Thursday, November 29, 2018 Project Units: U.S. Customary Units

Notes:

Channel Analysis: Channel Analysis Notes:

Input Parameters Channel Type: Trapezoidal

Side Slope 1 (Z1): 1.0000 ft/ft Side Slope 2 (Z2): 1.0000 ft/ft

Channel Width: 7.0000 ft Longitudinal Slope: 0.0540 ft/ft

Manning's n: 0.0621 Flow: 20.0000 cfs

Result Parameters Depth: 0.6735 ft

Area of Flow: 5.1682 ft^2 Wetted Perimeter: 8.9050 ft

Hydraulic Radius: 0.5804 ft Average Velocity: 3.8698 ft/s

Top Width: 8.3470 ft Froude Number: 0.8667

Critical Depth: 0.6144 ft Critical Velocity: 4.2747 ft/s

Critical Slope: 0.0734 ft/ft Critical Top Width: 8.23 ft

Calculated Max Shear Stress: 2.2695 lb/ft^2 Calculated Avg Shear Stress: 1.9556 lb/ft^2 matthew.dillin Callout Existing Ground matthew.dillin Callout Existing Ground matthew.dillin Text Box Channel Profile Upstream of Crossing matthew.dillin Text Box Channel Profile Downstream of Crossing matthew.dillin Text Box Existing Channel Profile 1"=20' matthew.dillin Callout Existing Roadway