wa-ef1712303_HYD_5008-100(0.75) AOP Report.pdf

Memorandum Western Federal Lands Highway Division

610 E. Fifth Street Vancouver, WA 98661-3801

OKANOGAN-WENATCHEE NATIONAL FORREST

FSR 5008100 MP 0.75 AOP HYDRAULICS REPORT

To: Craig Sanders, WFLHD Project Manager From: Matthew Dillin, P.E., WFLHD Hydraulics Engineer Date: September 11, 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) 5008100 at mile post (MP) 0.75, 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 5008100 MP 0.75 crossing requires an AOP structure (48°29’14.3”/-121°06’59.8”, NAD1983). The crossing is located on Break Creek with approximately 3.5 miles of potential fish habitat above the damaged site. It is anticipated that cutthroat trout may be present upstream and downstream of the crossing. 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 recurrence flood (206 cfs) 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 6 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 5008100 MP 0.75 AOP Culvert

Bear Creek is a tributary to the Methow River. The stream currently crosses Forest Road (FSR) 5008100 through an existing AOP structure located approximately 5.5 miles upstream of its confluence with the Methow. The current crossing is located within an alluvial fan depositional area. Alluvial fans are formed by the deposition of transported material as the stream gradient transitions to a shallow gradient from the steeper upstream gradient. Typically, there is very little topographic relief across the fan and the depositing sediment within the active channel causes recurring channel avulsions. This natural stream process has been exacerbated at the Bear Creek site by the influence of two fires within the last 12 years which have burned more than 50% of the contributing watershed. This has led to an increase of sediment being transported by Bear Creek to the project reach. The material ultimately deposits on the alluvial fan near the 5008100 crossing. It is anticipated that this accelerated deposition and avulsion process will continue for many years, until vegetation can be reestablished within the burned areas of the watershed and sediment transport within Bear Creek reaches a quasi-equilibrium.

Heavy rains during the winter of 2017 resulted in the mobilization of a large amount of sediment and debris upstream of the project reach. High flows carried the material downstream where they were deposited within the alluvial fan, causing the channel to aggrade and avulse near the FSR 5008100 crossing. The existing AOP culvert inlet was near completely plugged by deposited material. Flows overtopped the road and washed out some of the roadway material. The new channel currently flows along the roadway embankment before entering the existing AOP culvert which has an open area of just 18” available to transport flow and material. Downstream of the crossing the stream has deposited material causing the channel to take a new alignment through an existing campground. Roughly 600 feet downstream of the crossing the splits into multiple braided channels.

Due to the recent deposition across the valley floor and the recent adjustment in channel alignment, streambanks are poorly defined. Near the crossing the stream is in the process of downcutting to form a new low flow channel. Very little references remain for accurate measurements of bankfull widths.

Vegetation and bank features which remained intact downstream of the crossing (Appendix, photo 7)

September 2019 suggest that the natural bankfull width is roughly 7 feet with a channel slope around 3.5 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 between 5 feet and 10 feet with channel slopes around 7.5 percent. The existing stream appears to be in a transition zone between a step-pool bed form upstream of the crossing and a plane bed form just downstream of the crossing. Boulder, cobble, and gravel is the dominant bed material. Streambed gradation was measured by digital pebble count using FHWA Hydraulic Toolbox, version 4.2, and processing digital-scaled photographs at seven stream locations. Resulting gradation is D100 18 inches, D85 12 inches, D50 6.5 inches, and D15 2.5 inches (Fig.3).

Based on observed post flood conditions, the stream can likely carry a moderate 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 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 should be expected as the stream 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:

• Cleanout existing AOP structure.

• Install new culvert on existing stream alignment.

• Install a 74-foot long, corrugated metal culvert with an 12-foot diameter (Preliminary Sheet F.3).

• To maximize capacity for flow and debris conveyance and accommodate channel aggradation, raise the existing roadway profile 4 feet (elevation 2720 feet, project datum) to accommodate new culvert design.

• Place culvert floor at elevation 2706.0 feet upstream and at elevation 2703.5 feet downstream (project datum).

• Maximizing clearance for debris passage and maintenance access while economizing culvert size by installing culvert at a 3.4% grade.

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

• Slope the channel surface to match immediate downstream gradient (3.5 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.

September 2019

• 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 (30 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, 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 6 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.

September 2019

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 (7.6 sq. miles), canopy cover (47 percent), and mean annual precipitation (25.2 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 73 percent. Elevations range from 2380 to 6610 feet (NAD83/WGS84). A summary of peak discharges and their corresponding water depths at the culvert inlet are presented in Table 1.

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 3.5 percent and Manning’s Roughness coefficient of 0.055 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 3.33 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 0.074 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 sheets F.3, 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) 7.58 30 NA 86 127 165 206 NA

Water Elev. at Inlet (ft) 2,712.6 NA 2,714.1 2,714.7 2,715.3 2,715.9 NA

Clearance at Inlet (ft) 6.0 NA 4.5 3.9 3.3 2.7 NA

Water Depth at Inlet (ft) 1.1 NA 2.3 2.9 3.5 4.1 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 5008100 MP 0.75

AOP CULVERT

SITE LOCATION

MP 0.75

1000 feet0

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

N

DA = 7.6 sq. mi.

FIGURE 2

FSR 5008100 MP 0.75

AOP CULVERT

DRAINAGE AREA

0 5000 feet

FIGURE 3

FSR 5008100 MP 0.75

AOP CULVERT

STREAMBED GRADATION

FIGURE 4

FSR 5008100 MP 0.75

AOP CULVERT

2-YEAR FLOW VELOCITY

50 30 2040 10 0 10 20 30 40 5060 60

70 80

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.3

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

AOP

5.8 ft

Riprap Riprap

5.6 ft

NA

N

0.035 ft/ft

100 100

PLAN AND PROFILE

AOP CULVERT

FSR 5008-100 MP 0.75

0.033 ft/ft

3.0 ft

206 cfs

30 cfs

4.2 ft

1.1 ft

1V : 2H 1V : 2H

12 ft 12 ft

3.0 ft 74 ft

543810.48/1814445.65/2706.0 543751.28/1814402.08/2703.5

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. 2711.8' Prop. channel

Existing ground

Flow

Slope 3.4%

Slope 3.5% elev. 2703.5' DS invert elev. 2709.1' prop. channel m in

' m in

Flow elev. 2706.0' US invert

100yr WSE

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

144-inch pipe culvert road grade road centerline 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

Traveled way

PRELIM

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

Photos

PHOTO 1

PHOTO 2

PHOTO 3

10/10/2018

FSR 5008100 MP 0.75

The channel upstream of the existing culvert currently travels along the edge of the roadway prior to entering the existing culvert, causing damage to the existing embankment.

Existing AOP cuvlert almost completely burried. Only approximately 18" still accessable to flow.

Channel upstream of culvert.

Culvert Inlet.

Inlet almost completely burried with debris.

Culvert outlet.

PHOTO 4

PHOTO 5

PHOTO 6

10/10/2018

FSR 5008100 MP 0.75

New channel alignment downstream of crossing impacting an existing structure near the campground.

Abandoned channel upstream of culvert.

Example of one of the abandoned hisoric channel alignments just upstream of the existing roadway crossing.

Channel downstream of culvert.

Channel cutting a new alignment downstream of the culvert.

Structure downstream of the culvert.

PHOTO 7

PHOTO 8

PHOTO 9

10/10/2018

FSR 5008100 MP 0.75

Looking north at the roadway. Showing overflow path when flow overtopped the roadway. Also the proposed location for the new AOP culvert.

Roadway washed out east of the existing culvert.

Standing near exisitng culvert looking east along FS 5008100 at location where flows overtopped the roadway.

Temporary fix by FS.

Bankfull width measured roughly 500 feet downstream of the existing culvert.

Overflow path.

Due to excessive deposition across the valley floor and recent channel realigment, very little references remained for accurate measurements of bankfull widths. Vegetation which remained at this location suggests a bankfull width of roughly 7 feet with an approximate slope of 3.5%.

5008100(0.75) Flow

Basin Characteristics

Parameter Code Parameter Description Value Unit

DRNAREA Area that drains to a point on a stream 7.58 square miles

PRECPRIS10 Basin average mean annual precipitation for 1981 to 2010 from PRISM 25.2 inches

CANOPY_PCT Percentage of drainage area covered by canopy as described in OK SIR 2009_5267 46.8 percent

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

Parameter Code Parameter Name Value Units Min Limit Max Limit

DRNAREA Drainage Area 7.58 square miles 0.42 1330

PRECPRIS10 Mean Annual Precip PRISM 1981 2010 25.2 inches 8.86 84.2

CANOPY_PCT Percent Area Under Canopy 46.8 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 29.9 ft^3/s 9.78 91.3 77.2

5 Year Peak Flood 59.1 ft^3/s 21.3 164 69.1

10 Year Peak Flood 85.7 ft^3/s 29.8 247 72.2

25 Year Peak Flood 127 ft^3/s 39.6 405 81.2

50 Year Peak Flood 165 ft^3/s 47.2 576 89.2

100 Year Peak Flood 206 ft^3/s 54.4 784 96.9

200 Year Peak Flood 252 ft^3/s 60.7 1040 106

500 Year Peak Flood 326 ft^3/s 69.9 1520 120

Region ID: WA Workspace ID: WA20180917222018815000 Clicked Point (Latitude, Longitude): 48.48851, -120.11623 Time: 2018-09-17 15:20:33 -0700

HY-8 Culvert Analysis Report

Table 2 - Culvert Summary Table: 12

Straight Culvert

Inlet Elevation (invert): 2711.80 ft, Outlet Elevation (invert): 2709.10 ft

Culvert Length: 74.05 ft, Culvert Slope: 0.0365

Site Data - 12 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft

Inlet Elevation: 2706.00 ft Outlet Station: 74.00 ft

Outlet Elevation: 2703.30 ft Number of Barrels: 1

Culvert Data Summary - 12 Barrel Shape: Circular

Barrel Diameter: 12.00 ft Barrel Material: Corrugated Steel

Embedment: 69.60 in Barrel Manning's n: 0.0240 (top and sides)

Manning's n: 0.0550 (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 30.00 30.00 2712.89 0.668 1.093 3-M1t 0.643 0.570 0.908 0.908 2.768 4.176 10yr 86.00 86.00 2714.05 1.494 2.250 3-M1t 1.227 1.166 1.690 1.690 4.293 5.855 25yr 127.00 127.00 2714.74 2.008 2.943 3-M1t 1.567 1.523 2.117 2.117 5.096 6.581 50yr 165.00 165.00 2715.33 2.429 3.529 3-M1t 1.851 1.810 2.457 2.457 5.741 7.102 100yr 206.00 206.00 2715.92 2.836 4.118 3-M1t 2.136 2.099 2.783 2.783 6.375 7.565

Table 3 - Downstream Channel Rating Curve (Crossing: 5008100-0.75 Culvert (12))

Tailwater Channel Data - 5008100-0.75 Culvert (12) Tailwater Channel Option: Trapezoidal Channel

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

Channel Slope: 0.0350 Channel Manning's n: 0.0550

Channel Invert Elevation: 2709.10 ft

Roadway Data for Crossing: 5008100-0.75 Culvert (12) Roadway Profile Shape: Constant Roadway Elevation Crest Length: 20.00 ft

Crest Elevation: 2720.00 ft Roadway Surface: Gravel

Roadway Top Width: 18.00 ft

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

30.00 2710.01 0.91 4.18 1.98 0.82

86.00 2710.79 1.69 5.86 3.69 0.87

127.00 2711.22 2.12 6.58 4.62 0.88

165.00 2711.56 2.46 7.10 5.37 0.90

206.00 2711.88 2.78 7.56 6.08 0.91

Hydraulic Analysis Report

Project Data

Project Title:

Designer:

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: 0.0333 ft/ft

Manning's n: 0.0732

Flow: 30.0000 cfs

Result Parameters

Depth: 1.0932 ft

Area of Flow: 8.8474 ft^2

Wetted Perimeter: 10.0920 ft

Hydraulic Radius: 0.8767 ft

Average Velocity: 3.3908 ft/s

Top Width: 9.1864 ft

Froude Number: 0.6089

Critical Depth: 0.7974 ft

Critical Velocity: 4.8250 ft/s

Critical Slope: 0.0961 ft/ft

Critical Top Width: 8.59 ft

Calculated Max Shear Stress: 2.2716 lb/ft^2

Calculated Avg Shear Stress: 1.8217 lb/ft^2 matthew.dillin Text Box Channel Profile Downstream of Crossing matthew.dillin Text Box Channel Profile Upstream of Crossing matthew.dillin Callout Existing Roadway matthew.dillin Callout Existing Roadway matthew.dillin Callout Existing Ground matthew.dillin Callout Existing Ground matthew.dillin Text Box Existing Channel Profile 1"=20'