Hydraulic_Report.pdf

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Attached to: Greenbelt Park Federal contract opportunity
Solicitation number: 693C73-19-B-000004
Issued by: Department of Transportation Federal Highway Administration

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FP14_Eng.pdf	PDF	Nov 30, 2018
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October 2013

FINAL	HYDRAULICS	REPORT
GREE	11(1)

GREENBELT NATIONAL PARK, MD

Prepared by:

Abhishek Kapoor

Hydraulic Engineer

Eastern Federal Lands Highway Division

Sterling, Virginia

Signature Sheet

This

document

has

been

prepared

accordance

with

design

standards

and

methodologies

that

are

consistent

with

engineering

practice

the

date

its

preparation

unless

otherwise

noted.

Prepared by: Abhishek Kapoor

Signature: __________________________________ Date: ______________

Reviewed by: Libby Gress

Signature: __________________________________ Date: ______________

Accepted by: Ramesh Kotadia

Signature: __________________________________ Date: ______________

Table of Contents

Project Introduction

Summary of Recommendations

Overview of Project

Purpose and Scope

Project Location

Technical Analysis and Design

Hydrologic Analysis

Basin Delineation

Peak Flow Estimation

Hydraulic Analysis

Summary of Recommendations

List of Figures

Figure 1 – Project Vicinity Map

Figure 2 – Project Location Map

Figure 3 – Still Creek DA

Figure 4 – Culvert DA

List of Tables

Table 1 – Still Creek Peak Flows

Table 2 – Culvert Peak Flows

Table 3 – Still Creek Bridge Hydraulics

Table 4 – Still Creek Bridge Scour Elevations

Table 5 – Proposed Culvert Data

Table 6 – Allowable Head Water Elevations

Table 7 – Sheetflow to Conservation Areas Summary

Table 8 – Wet Swale Summary

Appendices

Appendix A – Project Information and Photos

A‐1 – Existing Culverts at Still Creek Crossing

A‐2 – Existing Culverts on Rte. 10, Sta. 201+64

A‐3 – Existing Culvert on Rte. 11, Sta. 3+11

Appendix B – Hydrologic Supporting Information

B ‐1 – Still Creek NSS hydrology

B‐2 – Culvert TR‐55 hydrology

B‐3 – SWM DA and Sheetlow locations

B‐4 – Soil Map

Appendix C – Hydraulic Supporting Information

C ‐1 – FEMA map

C‐2 – HEC RAS output for Still Creek and plan view of recommendations

C‐3 – Still Creek Bridge Scour Computations

C‐4 – Still Creek Scour Countermeasure Computations

C‐5 – Rte. 10 Sta. 201+64 Grading Plan and Proposed Riprap

C‐6 – Rt1. 11 Sta. 3+11 Proposed Riprap Basin and Grading Plan

C‐7 – HY‐8 Output for Culvert Analysis

C‐8 – Wet Swale Profiles and Cross Section

1 GREE 11(1)‐ Final Hydraulics Report Technical Services

PROJECT

INTRODUCTION

The

project

will

involve

improvement

the

roads

and

parking

lots

open

public

the

Greenbelt

National

Park

Prince

George’s

County,

MD.

According

the

park

official,

the

roads

had

suffered

damage

during

potentially

year

storm

June

2009

when

the

water

surface

had

come

within

foot

two

overtopping

the

road.

The

project

includes

culvert

replacements,

bridge

construction,

stormwater

management

and

pavement

rehabilitation.

SUMMARY	OF	RECOMMENDATIONS
The	following	are	the	hydraulic	recommendations	for	the	project:

1. The

existing

–

10.25’

span

6’

rise

corrugated

metal

arch

culverts

(Appendix

A‐1)

the

Park

Central

(Rte.

11)

the

Still

Creek

crossing

should

replaced

70’

long,

single

span

bridge.

addition,

relief

24”

corrugated

metal

pipes

(CMPs)

‐

one

side

and

the

other,

should

installed

reconnect

the

floodplain.

2. The

Still

Creek

channel

should

lined

with

Class

riprap

(FP

14),

countermeasure

for

scour.

Also

the

existing

scour

hole

should

filled

with

native

channel

material.

3. The

existing

–

36”

reinforced

concrete

pipes

(RCP)

(Appendix

A‐2)

Main

Entrance

Rd.

(Rte.

10)

should

replaced

7’

span

4’

rise

reinforced

concrete

box

(RCB).

4. The

existing

36”

CMP

(Appendix

A‐3)

Rte.

should

replaced

10’

span

6’

rise

reinforced

concrete

box

(RCB).

5. Wet

swales

and

sheetflow

conservations

areas

should

used

satisfy

MD’s

stormwater

management

requirements.

2 GREE 11(1)‐ Final Hydraulics Report Technical Services

OVERVIEW OF PROJECT

PURPOSE

AND

SCOPE

Still

Creek

currently

conveyed

under

the

Park

central

Road

via

two

10.25

feet

span

feet

rise

corrugated

metal

arch

culverts.

The

culverts

drain

urban

watershed

approximately

2.4

square

miles

and

appear

sized

adequately

but

urbanization

upstream

the

park

could

causing

increased

peak

runoff

and

degradation

the

stream

profile.

According

the

park

personnel,

year

storm

event

June

2009

had

caused

the

Still

Creek

come

within

foot

two

overtopping

the

road.

The

storm

appeared

have

accelerated

the

channel

degradation

and

piping

through

the

existing

culverts.

Due

this,

the

park

had

requested

Eastern

Federal

Lands

Highway

Division

(EFLHD)

assess

the

pavement

and

culvert

the

Still

Creek

crossing.

EFLHD

conducted

site

visit

October

2009

and

noticed

that

the

pavement

was

sagging

few

inches

above

the

existing

culverts.

Per

park

personnel,

this

sagging

had

not

changed

significantly

since

the

June

2009

storm.

Two

posts

supporting

the

timber

guardrail

along

the

curve

were

leaning

back

and

rail

had

rotated.

The

south

culvert

was

carrying

the

low

flow

and

piping

was

observed

between

the

two

culverts

the

eastern

fill

slope.

five

feet

deep

scour

hole

was

observed

the

outlet

and

the

culvert

outlets

were

perched

approximately

feet

above

the

water

surface.

The

culvert

bottoms

were

corroded

and

the

channel

appeared

have

degraded

both

upstream

and

downstream

the

culverts.

Also,

bank

erosion

the

Still

creek

had

caused

trees

fall

into

the

stream.

Due

the

above

mentioned

conditions,

the

park

had

initially

requested

EFLHD

repair

the

damage

sustained

the

Still

Creek

culverts

and

the

pavement

above

it.

But

further

site

investigation

had

revealed

that

large

portion

the

pavement

within

the

Greenbelt

National

Park

had

deteriorated

and

several

other

culverts

were

identified

deficient.

Also,

the

floodplain

the

Still

Creek

culverts

was

severely

constricted

from

approximately

250

feet

upstream

and

downstream

the

culvert

feet

the

culvert

crossing.

After

assessing

these

conditions,

was

decided

that

the

project

scope

should

include

the

following:

1. Floodplain	analysis	of	the	Still	Creek	crossing.
2. Pavement	rehabilitation	of	the	following	roads	and	parking	lots:

a. Route

b. Route

c. Park

Police

Substation

parking

area

(Rte.

0900)

d. Park

Headquarters

parking

area

(Rte.

0906)

e. Laurel

Picnic

area

access

road

(Rte.

0201)

and

the

Laurel

Picnic

parking

area

f. Holly

Picnic

Parking

area

(Rte.

0902)

g. Sweetgum

Picnic

Loop

(Rte.

0200)

and

the

Sweetgum

Picnic

parking

area

h. Dogwood

Natural

Trail

parking

area

(Rte.

0903)

3. Culvert	replacement	at	Sta.	201+64	on	Rte.	10
4. Culvert	replacement	at	Sta.	3+11	on	Rte.	11
5. Stormwater	management	(SWM)

3 GREE 11(1)‐ Final Hydraulics Report Technical Services

PROJECT

LOCATION

The

project

located

within

Greenbelt

National

Park

Prince

George’s

county,

MD.

Figures

and

show

vicinity

and

location

map

respectively.

FIGURE 1 – PROJECT VICINITY MAP

4 GREE 11(1)‐ Final Hydraulics Report Technical Services

FIGURE 2 – PROJECT LOCATION MAP

5 GREE 11(1)‐ Final Hydraulics Report Technical Services

TECHNICAL ANALYSIS AND DESIGN

HYDROLOGIC	ANALYSIS
1) Floodplain	Analysis	of	the	Still	Creek	Crossing

Hydrology

was

based

the

United

States

Geological

Survey’s

(USGS)

Regression

Equations

for

the

Rural

Western

Coastal

Plain

Region

MD.

Peak

flows

for

various

return

periods

were

computed

using

USGS

National

Streamflow

Statistics

(NSS)

Program

version

The

drainage

area

(DA)

contributing

floe

the

Still

Creek

crossing

was

found

out

2.36

square

miles

and

had

35%

impervious

area.

Table

shows

summary

the

peak

flows

for

the

Still

Creek

Crossing.

Figure

shows

the

map

for

the

Still

Creek

Crossing.

Please

refer

Appendix

B‐1

for

the

NSS

output

report.

2) Culvert

replacement

Rte.

Hydrology

was

based

the

Natural

Resource

Conservation

Service’s

(NRCS)

TR‐55

methodology.

Rainfall

data

was

obtained

from

the

National

Oceanic

and

Atmospheric

Administration’s

(NOAA)

Hydro

manual.

Soil

maps,

used

compute

the

curve

numbers,

were

obtained

from

USGS

Web

Soil

Survey

database.

The

for

the

culvert

crossing

Sta.

201+64

Rte.

was

70.69

acres

and

for

the

culvert

crossing

Sta.

3+11

Rte.

was

261.19

acres.

Table

shows

summary

the

peak

flows

for

both

the

culvert

crossings.

Figure

shows

the

DAs

for

both

the

culverts.

Please

refer

Appendix

B‐2

for

the

TR‐55

output

report.

3) SWM

The

Hydrology

for

SWM

was

based

the

methods

outlines

Maryland’s

Stormwater

Management

Guidelines

2010.

The

project

falls

primarily

under

the

redevelopment

category

and

rainfall

(PE)

inch

was

used

calculate

the

water

quality

volume

required

for

environmental

site

design

(ESDV).

Due

the

widening

the

road

the

proposed

bridge

approaches,

there

will

increase

1,353

ft2

the

impervious

area,

requiring

treatment

under

the

new

development

criteria.

Per

table

5.3

the

MD’s

SWM

guidelines,

for

the

existing

soil

group

1.8

inches

was

used

calculate

that

total

required

ESDV

for

the

project.

The

calculations

for

the

hydrology

for

SWM

are

shown

the

subsequent

sections.

Please

refer

Appendix

B‐3

for

the

SWM

DAs.

6 GREE 11(1)‐ Final Hydraulics Report Technical Services

BASIN

DELINEATION

Figures

and

below

show

the

drainage

areas

for

the

Still

Creek

crossing

and

the

culverts

Rtes.

and

respectively.

The

for

the

Still

Creek

crossing

was

combination

rural

and

urban

areas

with

approximately

33%

impervious

area.

The

for

the

culverts

was

mostly

rural

with

few

highways

contributing

the

impervious

area.

FIGURE 3 – STILL CREEK DA

7 GREE 11(1)‐ Final Hydraulics Report Technical Services

FIGURE 4 – CULVERT DA

8 GREE 11(1)‐ Final Hydraulics Report Technical Services

PEAK

FLOW

ESTIMATION

The

peak

design

flows

for

the

Still

Creek

and

the

culverts

for

various

return

periods

are

shown

Tables

and

below.

TABLE 1 – STILL CREEK PEAK FLOWS

RETURN PERIOD PEAK FLOWS (CFS)

Q2 389

Q10 1090

Q25 1740

Q50 2390

Q100 3240

Q500 6250

TABLE 2 – CULVERT PEAK FLOWS

RETURN PERIOD RTE. 10, STA 201+64 (CFS) RTE. 11, STA 3+11 (CFS)

Q2 50 140

Q10 115 340

Q25 165 500

Q50 210 650

Q100 260 825

The

ESDv

for

SWM

was

calculated

using

combination

redevelopment

and

new‐development

criteria

per

MD’s

guidelines.

Redevelopment

Per

MD’s

SWM

guidelines

2012,

the

existing

impervious

area

the

project

greater

than

40%

the

total

disturbed

area,

then

the

project

falls

under

redevelopment

requirements.

The

impervious

area

the

project

89.95%

and

ESDV

calculations

for

redevelopment

requirements

were

performed

follows:

Existing Impervious Area = 9.43 acres

Site Area = 10.13 acres

Imperviousness (I) = 9.43/10.13 = 93%

9 GREE 11(1)‐ Final Hydraulics Report Technical Services

Since

40%,

under

redevelopment

conditions,

the

project

must

either

decrease

existing

imperviousness

within

the

LOD

50%

provide

water

quality

treatment

for

equivalent

area.

ESDV = (PE)(Rv)(A)/12

Where, PE = 1 inch

RV = 0.05 + (0.009)(I); I = 100%

RV = 0.05 + (0.009 x 100) = 0.95

Total impervious area being disturbed = 6.52 acres

A = 0.5 * 6.52 acres = 3.26 acres

Therefore, ESDV = (1)(0.95)(3.26)/12

ESDV = 0.258 ac‐ ft x 43,560 sq.ft/ac = 11,242 cu. ft.

New Development

Due

the

widening

the

roadway

the

proposed

bridge

the

Still

Creek

crossing,

new

impervious

area

also

being

added

the

project.

The

amount

runoff

from

the

increase

imperviousness

will

reduced

level

equivalent

woods

good

condition

for

the

1‐year,

hour

rainfall

event.

The

calculations

for

ESDV

are

shown

below:

Existing Impervious Area = 23,544 ft2

Proposed Impervious Area = 24,897 ft2

New Impervious Area = 24,897 – 23,544 = 1,353 ft2 / 43560 sq.ft/ac = 0.031 acres

Total DA = 29,619 ft2

I = 24897/29619 = 84%

The

new

impervious

area

will

located

soils,

(Refer

Appendix

B‐4

for

the

Soil

Map),

therefore

according

Table

5.3

the

SWM

design

manual,

the

1.8

inches

for

0.03

acres.

ESDV = (PE)(Rv)(A)/12

Where, PE = 1.8 inch

RV = 0.05 + (0.009)(I); I = 100%

RV = 0.05 + (0.009 x 100) = 0.95

10 GREE 11(1)‐ Final Hydraulics Report Technical Services

A = 0.031 acres

ESDV = (1.8)(0.95)(0.031)/12

ESDV = 0.00442 ac‐ ft x 43,560 sq.ft/ac = 193 cu. ft.

Total ESDV = 193 + 11,242 = 11,435 cu. ft.

ESDV = 11,435 cu.ft.

11 GREE 11(1)‐ Final Hydraulics Report Technical Services

HYDRAULIC	ANALYSIS
1) Still	Creek	Crossing

a. Floodplain

Analysis:

The

existing

structure

consists

–

feet

long,

10.25

feet

span

feet

rise

corrugated

metal

arches.

The

channel

has

degraded

due

urbanization

the

watershed

and

also

due

the

year

storm

event

June

2009.

There

scour

hole

the

culvert

outlet

approximately

feet

deep

and

the

outlets

are

perched

feet

from

the

water

surface.

The

floodplain

has

been

constricted

from

approximately

250

feet

upstream

and

downstream

the

structure

feet

the

culvert

crossing.

Still

Creek

FEMA

mapped

floodplain

Zone

any

increase

the

100

year

water

surface

elevation

(WSEL)

had

limited

foot

(Appendix

C‐1).

Several

options

were

discussed

rectify

the

issue

including,

repairing

the

existing

culverts,

replacing

the

existing

culverts

with

similar

structure,

single

span

bridge,

multi‐span

bridge

and

single

span

bridge

with

relief

culverts.

Initially,

feet

long,

single

span

bridge

was

analyzed,

which

resulted

freeboard

4.48

feet

above

the

year

WSEL.

According

the

requirements

Chapter

the

Federal

Lands

Highway’s

(FLH)

Project

Development

and

Design

Manual

(PDDM),

bridges

should

designed

have

feet

freeboard

for

the

year

peak

flow.

The

feet

single

span

bridge

met

the

PDDM

requirements

for

the

bridge

but

would

not

reconnect

the

floodplain.

However,

the

NPS

had

requested

that

effort

should

made

reconnect

the

floodplain;

therefore

the

alternatives

were

limited

multi‐

span

bridge

and

single

span

bridge

with

relief

structures.

multi‐span

bridge

would

not

have

fit

the

natural

surroundings

the

park;

also

the

increased

cost

did

not

have

similar

effect

the

functionality

the

still

creek

crossing.

Therefore

the

analysis

was

limited

single

span

bridge

with

relief

culverts

either

side.

The

proposed

structure

consists

feet

long

single

span

bridge

with

‐

24”

CMPs

one

side

and

‐

24”

CMPs

the

other.

The

low

steel

elevation

(LSEL)

the

bridge

76.99’

with

freeboard

3.7

feet

for

the

year

peak

flow,

thus

satisfying

the

PDDM

requirements.

The

relief

culverts

were

placed

such

that

water

would

flow

through

them

for

higher

return

periods

and

assist

reconnecting

the

constricted

floodplain.

The

channel

will

graded

with

top

width

approximately

feet

mimic

the

existing

channel

upstream

and

downstream

the

structure.

manning’s

“n”

value

0.04

(“clean,

winding,

some

pools

and

shoals”

–

Chow)

was

used

for

the

channel,

and

for

the

overbanks,

value

0.08

(“Heavy

stand

timber,

few

down

trees,

little

undergrowth”

–

Chow)

was

used.

The

analysis

was

performed

using

HEC

RAS

version

4.1.

For

the

reach

boundary

conditions,

average

downstream

slope

0.005

ft/ft

was

used.

The

HEC

RAS

model

was

run

under

the

mixed

flow

regime.

Table

shows

the

freeboards

for

various

storm

events.

Please

refer

Appendix

C‐2

for

the

HEC

RAS

output

and

plan

view

our

recommendations.

12 GREE 11(1)‐ Final Hydraulics Report Technical Services

TABLE 3 – STILL CREEK BRIDGE HYDRAULICS

RETURN PERIOD WSEL (FT) FREEBOARD (FT)

Q2 68.91 8.08

Q10 71.25 5.74

Q25 72.36 4.63

Q50 73.29 3.7

Q100 74.45 2.54

Q500 79.65 ‐2.66

b. Scour

Analysis:

Scour

Analysis

and

countermeasure

design

for

the

Still

Creek

Bridge

was

performed

according

the

equations

Federal

Highway’s

(FHWA),

Hydraulic

Engineering

Circular

(HEC)

and

HEC

respectively.

Per

the

boring

logs,

the

presence

rock

could

not

established

the

site

auger

refusal

witnessed

even

after

drilling

approximately

feet.

The

total

scour

the

abutments

was

calculated

using

long

term

degradation

and

equations

for

contraction

scour

from

Chapter

HEC

18.

Per

the

particle

size

distribution

report

received

from

the

Geotechnical

division,

D50

1.2

(0.00394

ft)

was

used.

Initial

calculations

showed

that

the

scour

was

Live

Bed

Scour

and

the

corresponding

equations

were

used.

The

parameters

for

computation

the

contraction

scour

were

obtained

from

the

approach

and

the

bridge

upstream

cross

sections

the

HEC

RAS

model.

Since

information

the

long

–

term

degradation

was

unavailable,

value

foot

was

assumed

for

the

long

term

degradation

the

abutments.

Table

shows

the

scour

depths

and

the

resulting

scour

elevations

for

the

Still

Creek

Bridge.

These

elevations

were

calculated

from

the

proposed

channel

thalweg

elevation

feet.

Please

refer

Appendix

C‐3

for

summary

the

scour

calculations.

The

countermeasure

design

for

scour

was

performed

per

the

guidelines

Chapter

HEC

23,

Volume

was

recommended

that

Class

riprap

(FP

14)

should

used

countermeasure

against

scour

the

abutments

and

the

main

channel.

Please

refer

Appendix

C‐4

for

summary

calculations

for

scour

countermeasure

and

plan

and

cross

sectional

view

the

recommendations.

13 GREE 11(1)‐ Final Hydraulics Report Technical Services

TABLE 4 – STILL CREEK BRIDGE SCOUR ELEVATIONS

EVENT	SCOUR	TYPE
SCOUR	DEPTH	‐
N.	ABUTMENT

(FT)

SCOUR

ELEVATION

– N.

ABUTMENT

(FT)

SCOUR	DEPTH	‐
S.	ABUTMENT

(FT)

SCOUR

ELEVATION

– S.

ABUTMENT

(FT)

Year

Long Term 1.0

58.17

1.0

58.17

Contraction 4.83 4.83

Local 0.0 0.0

TOTAL 5.83 5.83

Year

Long Term 1.0

54.10

1.0

54.10

Contraction 8.90 8.90

Local 0.0 0.0

TOTAL 9.90 9.90

14 GREE 11(1)‐ Final Hydraulics Report Technical Services

2) Culvert	Design
a. Rte.	10,	Sta.	201+64:

The

existing

structure

consists

–

36”

RCPs

with

end

sections.

There

significant

erosion

the

banks

the

upstream

end

the

culverts

which

could

due

the

culverts

being

undersized

and

also

due

the

alignment

the

channel.

Per

Chapter

the

PDDM,

culverts

need

designed

convey

the

year

peak

flow

through

the

culvert,

while

satisfying

the

allowable

headwater

(AHW)

criteria.

The

culverts

were

analyzed

using

HY‐8,

version

7.3.

Based

the

analysis,

the

recommendation

replace

the

existing

structure

with

feet

long,

feet

span

feet

rise

RCB

with

1:1

beveled

headwalls

and

wingwalls.

The

area

around

the

headwalls

and

wingwalls

proposed

regarded

per

the

grading

plan

shown

Appendix

C‐5.

order

better

align

the

channel

with

the

culvert

and

protect

the

banks

from

erosion,

the

recommendations

include

installing

Class

riprap

(FP

14)

along

both

the

banks

the

upstream

end.

the

downstream

section,

the

proposed

ditch

should

also

lined

with

Class

riprap

(Refer

Appendix

C‐5

for

the

plan

view

and

cross

sections).

Tables

and

show

summary

the

culvert

data

and

the

AWH

elevations

respectively.

Appendix

C‐7

shows

the

HY‐8

output

report.

b. Rte.

11,

Sta.

3+11:

The

existing

structure

consists

36”

CMP

mitered

the

fill

slope.

There

significant

corrosion

the

culvert

bottom

and

the

channel

backs

downstream

the

culvert

are

also

eroded.

This

erosion

the

banks

could

due

the

culvert

being

undersized.

Per

Chapter

the

PDDM,

culverts

need

designed

convey

the

year

peak

flow

through

the

culvert,

while

satisfying

the

allowable

headwater

(AHW)

criteria.

The

culverts

were

analyzed

using

HY‐8,

version

7.3.

Based

the

analysis,

the

recommendation

replace

the

existing

structure

with

feet

long,

feet

span

feet

rise

RCB

with

1:1

beveled

headwalls

and

wingwalls.

Due

the

eroded

banks

and

erosive

outlet

velocities,

Class

riprap

basin

also

recommended

for

energy

dissipation

the

culvert

outlet.

The

energy

dissipater

was

designed

per

the

equations

Chapter

HEC

14.

The

area

around

the

headwalls

and

wingwalls

proposed

regarded

per

the

grading

plan

shown

Appendix

C‐6.

Tables

and

show

summary

the

culvert

data

and

the

AWH

elevations

respectively.

Appendix

C‐7

shows

the

HY‐8

output

report.

15 GREE 11(1)‐ Final Hydraulics Report Technical Services

TABLE 5 – PROPOSED CULVERT DATA

RTE./STA SIZE MATERIAL INLET EL. (FT) OUTLET EL. (FT) LENGTH (FT)

10/201+64 7 S x 4 R RCB 109.00 108.50 81

11/3+11 10 S x 6 R RCB 87.08 86.82 43

TABLE 6 – ALLOWABLE HEAD WATER ELEVATIONS

RTE./STA EVENT (YR) FLOW(CFS) AHW EL. (FT) HW EL. (FT)

10/201+64 25 165 113.80 113.09

11/3+11 25 500 94.28 93.93

16 GREE 11(1)‐ Final Hydraulics Report Technical Services

3) SWM

a. Sheetflow to Conservation areas:

Per

Chapter

Section

N‐3

MD’s

SWM

guidelines,

sheetflow

conservations

areas

can

used

treat

inch,

provided

the

minimum

buffer

width

100

feet

and

the

conservation

area

least

20,000

ft2.

Based

site

visit

July

2013

and

the

mapping

information,

was

determined

that

sheetflow

conservation

areas

can

used

separate

locations

throughout

the

project

site.

pea

gravel

diaphragm

will

also

constructed

the

side

the

road

where

the

conservation

area

located

order

create

sheetflow

conditions

into

the

conservation

areas.

The

buffers

should

not

disturbed

during

construction

except

for

temporary

impacts

associated

with

incidental

utility

construction.

Table

provides

the

approximate

locations

sheetflow,

along

with

their

respective

DAs

and

the

ESDVs.

Using

sheetflow

conservation

areas,

total

ESDV

6,082

ft3

will

provided

out

the

total

required

ESDV

11,435

ft3,

leaving

5,353

ft3

still

requiring

treatment.

These

locations

will

shown

the

final

construction

plans

along

with

their

respective

DAs.

Please

refer

Appendix

B‐3

for

the

locations

this

best

management

practice

(BMP).

TABLE 7 – SHEETFLOW TO CONSERVATIONS AREAS SUMMARY

STA DA (ft2) PE (IN) ESDv (ft3) LOCATION

200+58.2 to 201+45.79 1074 1 90 LEFT

3+94 to 5+17 1248 1 104 LEFT

12+43 to 17+76 10587 1 882 LEFT

18+30 to 27+43 16857 1 1405 LEFT

37+00 to 40+50 3668 1 306 RIGHT

41+42 to 45+36 4253 1 354 RIGHT

45+97 to 50+00 4037 1 336 RIGHT

51+30 to 52+30 1105 1 92 RIGHT

54+55 to 55+42 1007 1 84 LEFT

60+80 to 65+90 6193 1 516 LEFT

84+14 to 87+42 3592 1 299 LEFT

107+85 to 111+21 5570 1 464 RIGHT

113+00 to 120+00 13794 1 1150 RIGHT

TOTAL 6082

17 GREE 11(1)‐ Final Hydraulics Report Technical Services

b. Wet

Swales:

Per

Chapter

Section

M‐8

MD’s

SWM

guidelines,

wet

swales

should

designed

store

least

75%

the

ESDV.

The

ESDV

requiring

treatment

after

applying

sheetflow

conservation

areas

was

5,353

ft3.

Using

75%

this

volume,

total

ESDV

4,015

ft3

was

required

treated

using

wet

swales.

This

volume

was

provides

using

swales

separate

locations.

The

proposed

wet

swales

had

broken

down

into

segments

accommodate

the

difference

slopes

the

proposed

grade

line

and

maximum

allowable

slope

for

the

wet

swales.

Check

dams

were

proposed

every

feet

the

wet

swale

the

swale

segment

was

longer

than

feet.

minimum

bottom

width

feet

and

side

slopes

3H:1V

flatter

were

used

for

the

trapezoidal

cross

sections

the

swale.

Also,

freeboard

inches

was

provided

over

the

ESDV

depth

from

the

edge

pavement.

Please

refer

Appendix

C‐8

for

the

proposed

swale

profiles

and

cross

section.

Table

provides

summary

the

wet

swale

locations

and

their

proposed

dimensions.

TABLE 8 – WET SWALE SUMMARY

STATION LOCATION

BOTTOMD

WIDTH (FT)

SIDE SLOPE

(H:V)

DEPTH

(FT)

LENGTH

(FT)

100+00	–
102+00	LEFT	2	3	1.5	200

105+35	–
107+50	LEFT	2	3	1.5	215

TOTAL ESDv PROVIDED = 4046 FT3

There

were

several

locations

throughout

the

project

site,

where

–

site

treatment

the

runoff

was

not

possible

due

space

limitations

and

order

minimize

ground

disturbance

that

the

pristine

nature

the

project

site

could

maintained.

Therefore,

the

wet

swales

were

designed

overcompensate

for

the

lack

–

site

treatment

for

all

the

other

locations

and

will

provide

treatment

for

the

remainder

the

ESDV

for

the

entire

project

site.

This

was

discussed

initially

with

SWM

reviewers

and

they

had

agreed

the

plan

since

the

entire

project

site

drains

the

same

watershed.

18 GREE 11(1)‐ Final Hydraulics Report Technical Services

SUMMARY	OF	RECOMMENDATIONS
The	following	are	the	hydraulic	recommendations	for	the	project:

1. The

existing

–

10.25’

span

6’

rise

corrugated

metal

arch

culverts

the

Park

Central

(Rte.

11)

the

Still

Creek

crossing

should

replaced

70’

long,

single

span

bridge.

addition,

relief

24”

corrugated

metal

pipes

(CMPs)

‐

one

side

and

the

other,

should

installed

reconnect

the

floodplain.

2. The

Still

Creek

channel

should

lined

with

Class

riprap

(FP

14),

countermeasure

for

scour.

Also

the

existing

scour

hole

should

filled

with

native

channel

material.

3. The

existing

–

36”

reinforced

concrete

pipes

(RCP)

Main

Entrance

Rd.

(Rte.

10)

should

replaced

7’

span

4’

rise

reinforced

concrete

box

(RCB).

4. The

existing

36”

CMP

Rte.

should

replaced

10’

span

6’

rise

reinforced

concrete

box

(RCB).

5. Wet

swales

and

sheetflow

conservations

areas

should

used

satisfy

MD’s

stormwater

management

requirements.

19 GREE 11(1)‐ Final Hydraulics Report Technical Services

APPENDICES

abhishek.kapoor Typewritten Text

A-1: EXISTING CULVERTS AT STILL CREEK CROSSING

abhishek.kapoor Typewritten Text

A-2: EXISTING CULVERTS ON RTE. 10, STA. 201+64

A-3: EXISTING CULVERT ON RTE. 11, STA. 3+11

GREE 11(1)_AK_Hydrology_Bridge.txt National Streamflow Statistics Program Version 5 Based on Techniques and Methods Book 4-A6 Equations from database C:\Program Files\NSS\NSS_v5_2011-02-04.mdb Updated by tkoenig 2/4/2011 at 1:31:02 PM fix units for CSLBlue_ff in statewide TX region

Site: GREE 11(1), Maryland User: Abhishek Kapoor Date: Wednesday, June 22, 2011 02:37 PM

Equations for Maryland developed using English units

Rural Estimate: Still Creek- Rural Basin Drainage Area: 2.36 square miles 1 Region Region: Peak_Western_Coastal_Plain_2010_AHMMD Drainage_Area = 2.36 square miles Percent_Hydrologic_Soil_Type_C_or_D = 74.7 percent Percent_Impervious = 35 percent Crippen & Bue Region 4

Results for: Still Creek- Rural

Equations used:

PK1_25 = 5.18 * DRNAREA^0.694 * (IMPERV+1)^(0.382) * (SOILCorD+1)^(0.414) PK1_5 = 6.73 * DRNAREA^0.682 * (IMPERV+1)^(0.374) * (SOILCorD+1)^(0.429) PK2 = 7.61 * DRNAREA^0.678 * (IMPERV+1)^(0.362) * (SOILCorD+1)^(0.475) PK5 = 10.5 * DRNAREA^0.665 * (IMPERV+1)^(0.290) * (SOILCorD+1)^(0.612) PK10 = 13.1 * DRNAREA^0.653 * (IMPERV+1)^(0.270) * (SOILCorD+1)^(0.669) PK25 = 17.5 * DRNAREA^0.634 * (IMPERV+1)^(0.264) * (SOILCorD+1)^(0.719) PK50 = 21.2 * DRNAREA^0.621 * (IMPERV+1)^(0.263) * (SOILCorD+1)^(0.751) PK100 = 25.6 * DRNAREA^0.608 * (IMPERV+1)^(0.262) * (SOILCorD+1)^(0.781) PK200 = 30.5 * DRNAREA^0.596 * (IMPERV+1)^(0.261) * (SOILCorD+1)^(0.812) PK500 = 37.9 * DRNAREA^0.579 * (IMPERV+1)^(0.261) * (SOILCorD+1)^(0.849)

Value, Estimate Equivalent Statistic cfs Error, % Years

PK1_25 222 39 3.6

PK1_5 295 36 3.6

PK2 389 33 4.6

PK5 742 38 6.7

PK10 1090 43 8.2

PK25 1740 48 10

PK50 2390 54 11

PK100 3240 61 11

PK200 4350 70 10

PK500 6250 83 10

maximum: 7890 (for C&B region 4)

Urban Estimate: Still Creek - Urban Basin Drainage Area: 2.36 square miles 1 Region Region: Peak_Piedmont_Urban_2010_AHMMD Drainage_Area = 2.36 square miles Percent_Impervious = 35 percent

Results for: Still Creek - Urban abhishek.kapoor Typewritten Text

B-1:STILL CREEK NSS HYDROLOGY

abhishek.kapoor Typewritten Text Pg.1/2 abhishek.kapoor Typewritten Text

GREE 11(1)_AK_Hydrology_Bridge.txt Equations used:

PK1_25 = 17.85 * DRNAREA^0.652 * (IMPERV+1)^(0.635)

PK1_5 = 24.66 * DRNAREA^0.648 * (IMPERV+1)^(0.631)

PK2 = 37.01 * DRNAREA^0.635 * (IMPERV+1)^(0.588)

PK5 = 94.76 * DRNAREA^0.624 * (IMPERV+1)^(0.499)

PK10 = 169.2 * DRNAREA^0.622 * (IMPERV+1)^(0.435)

PK25 = 341 * DRNAREA^0.619 * (IMPERV+1)^(0.349)

PK50 = 562.4 * DRNAREA^0.619 * (IMPERV+1)^(0.284)

PK100 = 898.3 * DRNAREA^0.619 * (IMPERV+1)^(0.222)

PK200 = 1413 * DRNAREA^0.621 * (IMPERV+1)^(0.160)

PK500 = 2529 * DRNAREA^0.623 * (IMPERV+1)^(0.079)

Value, Standard Statistic cfs Error, %

PK1_25 304

PK1_5 413

PK2 525

PK5 968

PK10 1370

PK25 2030

PK50 2650

PK100 3390

PK200 4270

PK500 5730

abhishek.kapoor

Pg. 2/2

WinTR-55 Current Data Description

--- Identification Data ---

User: DW Date: 7/5/2012 Project: PRA-GREE 11(1) Units: English SubTitle: Greenbelt Park Areal Units: Acres State: Maryland County: Prince George's Filename: M:\PROJECTS\gree\11(1)\Techserv\Hydra\Computations\Computer data\GREE 11(1)_DW_Hydrology_Culvert

--- Sub-Area Data ---

Name Description Reach Area(ac) RCN Tc STA 201+64 Upper Culvert Outlet 70.69 76 .781 STA 3+11 Lower Culvert Outlet 261.19 73 .893

Total area: 331.88 (ac)

--- Storm Data --

Rainfall Depth by Rainfall Return Period

2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr 1-Yr

(in) (in) (in) (in) (in) (in) (in)

3.19 4.1 4.91 6.14 7.24 8.47 2.64

Storm Data Source: User-provided custom storm data Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard>

WinTR-55, Version 1.00.09 Page 1 7/5/2012 12:47:52 PM abhishek.kapoor Typewritten Text B-2: Culvert TR-55 HYDROLOGY abhishek.kapoor

Pr. 1/7

DW PRA-GREE 11(1)

Greenbelt Park Prince George's County, Maryland

Storm Data

Rainfall Depth by Rainfall Return Period

2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr 1-Yr

(in) (in) (in) (in) (in) (in) (in)

3.19 4.1 4.91 6.14 7.24 8.47 2.64

Storm Data Source: User-provided custom storm data Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard>

WinTR-55, Version 1.00.09 Page 1 7/5/2012 12:47:52 PM abhishek.kapoor

Pg. 2/7

Prince George's County, Maryland

Watershed Peak Table

Sub-Area Peak Flow by Rainfall Return Period or Reach ANALYSIS: 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)

SUBAREAS

STA 201+64 50.42 82.94 114.16 163.24 209.04 261.41

STA 3+11 139.07 240.53 340.48 501.48 651.28 823.11

REACHES

OUTLET 187.75 321.34 450.89 660.96 855.50 1077.24

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Pg. 3/7

Prince George's County, Maryland

Hydrograph Peak/Peak Time Table

Sub-Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach ANALYSIS: 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)

(hr) (hr) (hr) (hr) (hr) (hr)

SUBAREAS

STA 201+64 50.42 82.94 114.16 163.24 209.04 261.41

12.35 12.38 12.36 12.37 12.36 12.35

STA 3+11 139.07 240.53 340.48 501.48 651.28 823.11

12.48 12.47 12.44 12.42 12.40 12.43

REACHES

OUTLET 187.75 321.34 450.89 660.96 855.50 1077.24

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Pg. 4/7

Prince George's County, Maryland

Sub-Area Summary Table

Sub-Area Drainage Time of Curve Receiving Sub-Area Identifier Area Concentration Number Reach Description

(ac) (hr) STA 201+64 70.69 0.781 76 Outlet Upper Culvert STA 3+11 261.19 0.893 73 Outlet Lower Culvert

Total Area: 331.88 (ac)

WinTR-55, Version 1.00.09 Page 1 7/5/2012 12:47:52 PM abhishek.kapoor

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Prince George's County, Maryland

Sub-Area Time of Concentration Details

Sub-Area Flow Mannings's End Wetted Travel Identifier/ Length Slope n Area Perimeter Velocity Time

(ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr)

STA 201+64

SHEET 100 0.0200 0.800 0.624

SHALLOW 1781 0.0381 0.050 0.157

Time of Concentration .781

STA 3+11

SHEET 100 0.0200 0.800 0.624

SHALLOW 1781 0.0421 0.050 0.149

CHANNEL 2742 6.332 0.120

Time of Concentration .893

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Pg. 6/7

Prince George's County, Maryland

Sub-Area Land Use and Curve Number Details

Sub-Area Hydrologic Sub-Area Curve Identifier Land Use Soil Area Number Group (ac) STA 201+64Woods - grass combination (fair) B 2.01 65 Woods - grass combination (fair) C 60.22 76 Woods - grass combination (fair) D 8.46 82

Total Area / Weighted Curve Number 70.69 76

STA 3+11 Woods - grass combination (fair) A 21.47 43 Woods - grass combination (fair) B 33.97 65 Woods - grass combination (fair) C 159.16 76 Woods - grass combination (fair) D 46.59 82

Total Area / Weighted Curve Number 261.19 73

WinTR-55, Version 1.00.09 Page 1 7/5/2012 12:47:53 PM abhishek.kapoor Typewritten Text abhishek.kapoor

Pg. 7/7

DA=1074 sq.ft.

Min Width=100 ft.

Conservation Area=20764 sq.ft.

" O

A K

200+00

110 1

" O

A K abhishek.kapoor Typewritten Text B-3: SWM DA and SHEETLOW LOCATIONS abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor

Pg. 1/11

DA=1248 sq.ft.

Conservation Area=20026 sq.ft.

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Pg. 2/11

DA=10587 sq.ft.

Conservation Area=67897 sq.ft.

400+00 abhishek.kapoor

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DA=16857 sq.ft.

Conservation Area=116984 sq.ft.

12" OAK

+00

400+00

12" OAK

abhishek.kapoor

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DA=3668 sq.ft.

DA=4253 sq.ft.

Min Width=100 ft.

Conservation Area=37685 sq.ft.

Min Width=100 ft.

Conservation Area=41462 sq.ft.

Conservation Area=39683 sq.ft.

180 18 abhishek.kapoor

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DA=4037 sq.ft.

DA=1105 sq.ft.

Conservation Area=39683 sq.ft.

" O

A K

300+00

310+00

" O

A K abhishek.kapoor

Pg. 6/11

DA=1105 sq.ft.

DA=1007 sq.ft.

Min Width=100 ft.

Conservation Area=20113 sq.ft.

Conservation Area=20354 sq.ft.

115 120 125 abhishek.kapoor

Pg. 7/11

DA=6193 sq.ft.

Conservation Area=55423 sq.ft.

65+ abhishek.kapoor

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DA=3592 sq.ft.

Conservation Area=33358 sq.ft.

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DA=5570 sq.ft.Min Width=100 ft.

Conservation Area=39623 sq.ft.

110+00 abhishek.kapoor

Pg. 10/11

DA=13794 sq.ft.

Conservation Area=134972 sq.ft.

115+00

" O

A K abhishek.kapoor Typewritten Text abhishek.kapoor

Pg. 11/11

Indian Creek Tributary

Greenbelt Rd

Ke nilw ort h A ve

Ridge Rd

Edm ons ton Rd

Hano ver

Pkwy

Seminole St Ruatan St

Breezewood Dr

Ch err yw oo d L n nd

Av e

Pontiac St

Crescent Rd

60th Ave

Osage St

Lakeside Dr

Quebec St Quebec Pl

Ch err yw oo d T er

Sp ring hill Ln

Springhill Dr

Lakecrest Dr

Breezewood Ct th

Springhill Ct

Greenbrook Dr

Ora Glen Dr

Wa lke r D r

Charlton Ave

West che ste r P ark Dr

Cu nn ing ha m Dr rd

Av e

Greenway Center Dr

Ed mo ns ton

Te r

Vanity Fair Dr

Tecumseh Pl

Belle Point DrCapitol Dr

Marke t Ln

Hanover Dr

Edmonston Ct

Maplewood Ct

Pinecrest Ct

Southway 7 Ct

Ridge 6 Ct

Ridge 19 Ct

La ke

D r

Southway 10 Ct

Lakeview Cir

Lakecrest CirGreenbelt Rd th

Av e

Ke nilw ort h A ve

Edmonston Rd

63r d A ve rd

Av e

Greenbelt

Berwyn Heights

UdaF

RuB

Iu RuB

CcC

Sa C

CdD

CcD

CcC

Sn B

CcC

CdD

CcD

Urr B

RcB RuBCcC

CcC

SaC

CcE

EwC Gb

BaC

RuB

CdD

UrrB

Gb B

CcC

EwB

SaC

RcB

BaB

CcC

Gb D

CdD

RcB

BaB

Ba B

EwC

GbB

EwB

RuB

SaC

BaB

RcB

SnB

RcB

CdD

334500

334800

335100

335400

335700

336000

336300

336600

336900

337200

337500

337800

0 1,000 2,000 3,000500 Feet

0 400 800 1,200200 Meters

39° 0' 20''

° 5

38° 59' 7''

° 5

38° 59' 5''

39° 0' 18''

° 5 4'

° 5

Map Scale: 1:16,300 if printed on A size (8.5" x 11") sheet.

Hydrologic Soil Group—Prince George's County, Maryland (Gree 11(1))

Natural ResourcesNatural ResourcesNatural ResourcesNatural Resources Conservation ServiceConservation ServiceConservation ServiceConservation Service

Web Soil Survey National Cooperative Soil Survey

12/9/2011 abhishek.kapoor Typewritten Text

B-4: SOIL MAP

abhishek.kapoor Typewritten Text Pg. 1/4 abhishek.kapoor Typewritten Text

MAP LEGEND MAP INFORMATION

Area of Interest (AOI) Area of Interest (AOI)

Soils Soil Map Units

Soil Ratings A

A/D

B/D

C/D

Not rated or not available

Political Features Cities

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Map Scale: 1:16,300 if printed on A size (8.5" × 11") sheet.

The soil surveys that comprise your AOI were mapped at 1:12,000.

Please rely on the bar scale on each map sheet for accurate map measurements.

Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: UTM Zone 18N NAD83

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Prince George's County, Maryland Survey Area Data: Version 8, Dec 16, 2009

Date(s) aerial images were photographed: 6/21/2005

The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Hydrologic Soil Group–Prince George's County, Maryland (Gree 11(1))

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

12/9/2011 abhishek.kapoor

Pg. 2/4

Hydrologic Soil Group

Hydrologic Soil Group— Summary by Map Unit — Prince George's County, Maryland (MD033)

Map unit symbol Map unit name Rating Acres in AOI Percent of AOI

BaB Beltsville silt loam, 2 to 5 percent slopes C 10.7 2.1%

BaC Beltsville silt loam, 5 to 10 percent slopes C 5.9 1.1%

CcC Christiana-Downer complex, 5 to 10 percent slopes

C 63.0 12.3%

CcD Christiana-Downer complex, 10 to 15 percent slopes

C 22.4 4.4%

CcE Christiana-Downer complex, 15 to 25 percent slopes

C 7.8 1.5%

CdD Christiana-Downer-Urban land complex, 5 to 15 percent slopes

C 30.7 6.0%

EwB Evesboro-Downer complex 0 to 5 percent slopes

A 8.7 1.7%

EwC Evesboro-Downer complex, 5 to 10 percent slopes

A 10.4 2.0%

GbB Galestown-Urban land complex, 0 to 5 percent slopes

A 18.8 3.7%

GbD Galestown-Urban land complex, 5 to 15 percent slopes

A 3.1 0.6%

Iu Issue-Urban land complex, occasionally flooded

C 9.7 1.9%

RcB Russett-Christiana complex, 2 to 5 percent slopes

C 18.7 3.7%

RuB Russett-Christiana-Urban land complex, 0 to 5 percent slopes

C 80.9 15.8%

SaC Sassafras sandy loam, 5 to 10 percent slopes

B 27.8 5.5%

SnB Sassafras-Urban land complex, 0 to 5 percent slopes

B 11.8 2.3%

UdaF Udorthents, highway, 0 to 65 percent slopes

D 139.2 27.3%

UrrB Urban land-Russett-Christiana complex, 0 to 5 percent slopes

D 15.1 3.0%

ZS Zekiah and Issue soils, frequently flooded D 26.0 5.1%

Totals for Area of Interest 510.4 100.0%

Hydrologic Soil Group–Prince George's County, Maryland Gree 11(1)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

12/9/2011 abhishek.kapoor

Pg. 3/4

Description

Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission.

Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.

Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material.

These soils have a very slow rate of water transmission.

If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes.

Rating Options

Aggregation Method: Dominant Condition

Component Percent Cutoff: None Specified

Tie-break Rule: Higher

Hydrologic Soil Group–Prince George's County, Maryland Gree 11(1)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

12/9/2011 abhishek.kapoor

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Oval abhishek.kapoor Callout Still Creek Crossing abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text

C-1: FEMA MAP

HEC-RAS Plan: Pr - Final River: 003 Reach: SC

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

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

SC 1082.130 Q2 389.00 66.89 71.30 69.66 71.65 0.004024 4.78 89.34 55.86 0.46

SC 1082.130 Q5 742.00 66.89 72.82 71.29 73.15 0.002863 5.06 243.66 138.15 0.41

SC 1082.130 Q10 1090.00 66.89 73.44 72.46 73.84 0.003256 5.86 348.48 200.17 0.45

SC 1082.130 Q25 1740.00 66.89 74.39 73.37 74.80 0.003242 6.52 574.80 254.64 0.46

SC 1082.130 Q50 2390.00 66.89 75.17 74.05 75.58 0.003095 6.89 781.37 276.40 0.46

SC 1082.130 Q100 3240.00 66.89 76.11 74.62 76.49 0.002795 7.12 1052.90 302.63 0.44

SC 1082.130 Q200 4350.00 66.89 77.35 75.21 77.69 0.002272 7.07 1450.12 337.35 0.41

SC 1082.130 Q500 6250.00 66.89 80.35 76.02 80.54 0.001037 5.77 2589.20 411.57 0.29

SC 1020.410 Q2 389.00 66.54 71.10 69.39 71.40 0.003543 4.42 87.96 27.77 0.44

SC 1020.410 Q5 742.00 66.54 72.56 70.62 72.94 0.003678 5.15 209.84 211.50 0.46

SC 1020.410 Q10 1090.00 66.54 73.26 71.66 73.63 0.003277 5.44 367.65 238.54 0.45

SC 1020.410 Q25 1740.00 66.54 74.25 73.30 74.59 0.002845 5.78 622.42 276.66 0.43

SC 1020.410 Q50 2390.00 66.54 75.04 73.80 75.38 0.002609 6.04 853.95 307.24 0.42

SC 1020.410 Q100 3240.00 66.54 76.00 74.32 76.32 0.002279 6.20 1165.66 344.13 0.40

SC 1020.410 Q200 4350.00 66.54 77.27 74.87 77.54 0.001789 6.12 1633.44 393.05 0.37

SC 1020.410 Q500 6250.00 66.54 80.33 75.66 80.48 0.000771 4.92 3014.31 498.37 0.25

SC 949.650 Q2 389.00 66.07 70.79 69.14 71.14 0.003745 4.73 82.22 52.28 0.45

SC 949.650 Q5 742.00 66.07 72.24 70.39 72.68 0.003560 5.61 211.37 231.73 0.46

SC 949.650 Q10 1090.00 66.07 72.91 72.18 73.37 0.003634 6.19 331.23 268.74 0.47

SC 949.650 Q25 1740.00 66.07 73.88 73.08 74.36 0.003580 6.86 515.68 291.28 0.48

SC 949.650 Q50 2390.00 66.07 74.64 73.62 75.15 0.003588 7.41 669.30 309.14 0.49

SC 949.650 Q100 3240.00 66.07 75.59 74.19 76.11 0.003378 7.82 869.02 331.29 0.49

SC 949.650 Q200 4350.00 66.07 76.89 74.81 77.37 0.002845 7.93 1157.70 361.47 0.46

SC 949.650 Q500 6250.00 66.07 80.08 75.70 80.39 0.001421 6.81 1949.83 434.04 0.34

SC 860.770 Q2 389.00 66.44 70.30 69.29 70.73 0.005778 5.25 74.07 25.92 0.55

SC 860.770 Q5 742.00 66.44 71.79 70.39 72.31 0.004962 6.00 185.93 177.66 0.52

SC 860.770 Q10 1090.00 66.44 72.60 72.04 73.03 0.004003 5.97 345.06 226.39 0.48

SC 860.770 Q25 1740.00 66.44 73.67 72.78 74.02 0.003152 6.05 604.78 259.58 0.44

SC 860.770 Q50 2390.00 66.44 74.48 73.26 74.82 0.002845 6.26 824.56 280.67 0.43

SC 860.770 Q100 3240.00 66.44 75.48 73.76 75.79 0.002426 6.34 1116.14 302.02 0.40

SC 860.770 Q200 4350.00 66.44 76.83 74.32 77.10 0.001868 6.19 1543.26 330.82 0.36

SC 860.770 Q500 6250.00 66.44 80.09 75.08 80.24 0.000832 5.07 2733.23 398.35 0.25

SC 799.490 Q2 389.00 65.60 70.07 68.62 70.40 0.003917 4.65 83.59 26.98 0.47

SC 799.490 Q5 742.00 65.60 71.57 69.80 72.02 0.003849 5.53 181.86 147.06 0.48

SC 799.490 Q10 1090.00 65.60 72.37 70.72 72.80 0.003479 5.86 335.54 227.34 0.46

SC 799.490 Q25 1740.00 65.60 73.50 72.52 73.86 0.002672 5.90 622.49 268.02 0.42

SC 799.490 Q50 2390.00 65.60 74.33 73.07 74.66 0.002441 6.13 851.64 288.10 0.41

SC 799.490 Q100 3240.00 65.60 75.35 73.60 75.66 0.002104 6.24 1158.85 313.92 0.39

SC 799.490 Q200 4350.00 65.60 76.73 74.15 77.00 0.001621 6.10 1617.73 348.95 0.35

SC 799.490 Q500 6250.00 65.60 80.05 74.93 80.20 0.000720 4.98 2913.87 431.63 0.25

SC 718.400 Q2 389.00 65.19 69.63 68.63 70.02 0.005703 5.03 77.37 30.65 0.56

SC 718.400 Q5 742.00 65.19 71.23 69.75 71.69 0.004225 5.53 163.82 107.99 0.50

SC 718.400 Q10 1090.00 65.19 71.83 70.60 72.43 0.004987 6.53 229.99 111.33 0.55

SC 718.400 Q25 1740.00 65.19 72.75 72.05 73.49 0.005282 7.64 372.01 196.12 0.59

SC 718.400 Q50 2390.00 65.19 73.62 72.90 74.33 0.004625 7.92 548.18 210.19 0.56

SC 718.400 Q100 3240.00 65.19 74.76 73.56 75.38 0.003587 7.82 799.81 228.79 0.51

SC 718.400 Q200 4350.00 65.19 76.28 74.23 76.79 0.002560 7.50 1166.30 255.03 0.45

SC 718.400 Q500 6250.00 65.19 79.83 75.16 80.10 0.001064 6.06 2181.71 315.90 0.30

SC 627.898 Q2 389.00 64.19 68.98 67.86 69.46 0.006404 5.56 69.91 23.41 0.57

SC 627.898 Q5 742.00 64.19 70.54 69.17 71.19 0.006832 6.58 139.07 141.24 0.60

SC 627.898 Q10 1090.00 64.19 71.35 70.97 71.92 0.005976 6.60 266.85 167.85 0.58

SC 627.898 Q25 1740.00 64.19 72.50 71.73 72.97 0.004299 6.61 494.41 259.69 0.51

SC 627.898 Q50 2390.00 64.19 73.51 72.26 73.87 0.003060 6.28 788.39 304.52 0.44

SC 627.898 Q100 3240.00 64.19 74.74 72.93 75.02 0.002113 5.89 1182.10 334.71 0.38

SC 627.898 Q200 4350.00 64.19 76.30 73.49 76.52 0.001413 5.47 1734.40 371.04 0.32

SC 627.898 Q500 6250.00 64.19 79.87 74.24 79.98 0.000557 4.29 3211.85 447.48 0.21

SC 567.983 Q2 389.00 64.00 68.91 66.45 69.07 0.001507 3.19 121.78 34.63 0.30

SC 567.983 Q5 742.00 64.00 70.50 67.59 70.73 0.001404 3.94 246.11 145.09 0.31

SC 567.983 Q10 1090.00 64.00 71.25 68.45 71.56 0.001703 4.75 348.25 199.98 0.35

SC 567.983 Q25 1740.00 64.00 72.36 70.19 72.74 0.001868 5.59 546.11 281.23 0.37

SC 567.983 Q50 2390.00 64.00 73.29 71.00 73.71 0.001882 6.10 732.66 335.19 0.38

abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text

C-2: STILL CREEK HEC RAS OUTPUT AND PLAN VIEW OF RECOMMENDATIONS

abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor Typewritten Text abhishek.kapoor

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HEC-RAS Plan: Pr - Final River: 003 Reach: SC (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

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

SC 567.983 Q100 3240.00 64.00 74.45 72.08 74.86 0.001719 6.39 987.71 362.13 0.37

SC 567.983 Q200 4350.00 64.00 76.02 72.91 76.39 0.001370 6.35 1341.27 375.00 0.34

SC 567.983 Q500 6250.00 64.00 79.65 74.12 79.91 0.000706 5.55 2158.62 375.00 0.26

SC 540 Mult Open

SC 520.051 Q2 389.00 63.76 68.85 66.21 68.99 0.001289 3.03 128.47 40.65 0.28

SC 520.051 Q5 742.00 63.76 70.43 67.35 70.64 0.001258 3.81 254.68 137.88 0.29

SC 520.051 Q10 1090.00 63.76 71.13 68.21 71.43 0.001606 4.68 342.88 181.58 0.34

SC 520.051 Q25 1740.00 63.76 72.06 69.69 72.50 0.002100 5.89 495.45 244.08 0.40

SC 520.051 Q50 2390.00 63.76 72.80 70.89 73.34 0.002387 6.72 626.44 296.11 0.43

SC 520.051 Q100 3240.00 63.76 73.61 72.06 74.26 0.002701 7.65 779.03 322.17 0.46

SC 520.051 Q200 4350.00 63.76 74.51 72.73 75.26 0.002914 8.51 959.54 340.24 0.49

SC 520.051 Q500 6250.00 63.76 75.79 74.02 76.70 0.003196 9.70 1215.36 350.00 0.53

SC 425.186 Q2 389.00 63.16 68.67 65.86 68.85 0.001564 3.42 113.71 27.12 0.29

SC 425.186 Q5 742.00 63.16 70.22 67.11 70.48 0.002310 4.26 250.74 173.18 0.36

SC 425.186 Q10 1090.00 63.16 70.97 68.05 71.23 0.002416 4.58 393.22 197.89 0.37

SC 425.186 Q25 1740.00 63.16 71.91 70.59 72.22 0.002464 5.23 591.62 225.37 0.39

SC 425.186 Q50 2390.00 63.16 72.67 71.12 73.01 0.002489 5.72 772.82 251.43 0.40

SC 425.186 Q100 3240.00 63.16 73.50 71.68 73.87 0.002513 6.23 993.17 278.85 0.41

SC 425.186 Q200 4350.00 63.16 74.43 72.30 74.84 0.002521 6.77 1264.91 309.33 0.42

SC 425.186 Q500 6250.00 63.16 75.75 73.18 76.21 0.002521 7.48 1701.19 352.80 0.43

SC 325.000 Q2 389.00 63.10 68.36 66.21 68.64 0.002681 4.23 92.01 23.80 0.38

SC 325.000 Q5 742.00 63.10 69.85 67.51 70.21 0.002947 5.08 231.34 166.73 0.41

SC 325.000 Q10 1090.00 63.10 70.62 68.54 70.97 0.002902 5.45 361.94 177.36 0.41

SC 325.000 Q25 1740.00 63.10 71.54 70.48 71.95 0.003138 6.30 533.13 194.34 0.44

SC 325.000 Q50 2390.00 63.10 72.27 71.04 72.73 0.003295 6.94 682.54 211.54 0.46

SC 325.000 Q100 3240.00 63.10 73.08 71.63 73.59 0.003448 7.63 860.88 231.85 0.48

SC 325.000 Q200 4350.00 63.10 73.97 72.28 74.55 0.003568 8.35 1078.94 254.68 0.50

SC 325.000 Q500 6250.00 63.10 75.25 73.21 75.91 0.003691 9.30 1426.13 287.87 0.52

SC 225.000 Q2 389.00 63.04 67.82 66.57 68.26 0.005547 5.32 73.07 24.48 0.54

SC 225.000 Q5 742.00 63.04 69.50 67.91 69.87 0.003709 5.31 228.98 161.40 0.46

SC 225.000 Q10 1090.00 63.04 70.32 69.46 70.65 0.003106 5.45 363.68 168.86 0.44

SC 225.000 Q25 1740.00 63.04 71.19 70.16 71.60 0.003399 6.37 515.36 177.21 0.47

SC 225.000 Q50 2390.00 63.04 71.87 70.68 72.36 0.003692 7.15 639.88 188.90 0.50

SC 225.000 Q100 3240.00 63.04 72.62 71.26 73.19 0.003998 8.01 785.24 201.69 0.53

SC 225.000 Q200 4350.00 63.04 73.44 71.91 74.12 0.004323 8.95 956.71 218.99 0.56

SC 225.000 Q500 6250.00 63.04 74.61 72.84 75.45 0.004681 10.21 1234.56 248.75 0.60

SC 126.198 Q2 389.00 61.76 67.32 65.71 67.73 0.005000 5.13 75.82 24.18 0.51

SC 126.198 Q5 742.00 61.76 68.91 67.25 69.43 0.005009 5.96 160.47 104.38 0.52

SC 126.198 Q10 1090.00 61.76 69.71 68.75 70.25 0.005006 6.38 279.98 169.37 0.53

SC 126.198 Q25 1740.00 61.76 70.62 70.00 71.17 0.005002 7.05 443.38 193.21 0.55

SC 126.198 Q50 2390.00 61.76 71.30 70.54 71.91 0.005008 7.67 581.53 208.70 0.56

SC 126.198 Q100 3240.00 61.76 72.07 71.11 72.72 0.005001 8.31 746.98 225.89 0.57

SC 126.198 Q200 4350.00 61.76 72.91 71.73 73.63 0.005002 9.00 945.80 244.96 0.58

SC 126.198 Q500 6250.00 61.76 74.12 72.63 74.93 0.005003 9.95 1258.80 272.29 0.59 abhishek.kapoor

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