Hydraulic and Hydrologic Considerations

in Planning

FLOOD RISK MANAGEMENT

CLASS EXERCISE

Chuck Shadie

Mississippi Valley Division

Objective

• The students will complete an exercise designed to improve their abilities in selecting the types of alternatives to analyze during a flood damage reduction study.

Exercise Impacts of Various Flood

Risk Management Measures

• Have the students predict the flood reduction impacts of various types of measures.

• Explore the consequences of such measures on upstream and downstream areas of the watershed. 

Denham SpringsDenham Springs

Lake Lake MaurepasMaurepas

New OrleansNew Orleans

MISSISSIPPIMISSISSIPPI

LOUISIANALOUISIANA

Lake Lake PontchartrainPontchartrain

Baton RougeBaton Rouge

E. Baton R.

Comite RiverComite River

St.

Hel

ena

Livingston

E. Feliciana

Ascension

St.

Jo

hn

St. James

Iberville

AmiteWilkerson

Franklin Lin

coln

Amite RiverAmite River

Amite River and Tributaries Study Map

The Amite River BasinThe Amite River Basin

- 2,200 square miles- 2,200 square miles

- Includes portions of East Baton Rouge,- Includes portions of East Baton Rouge, Ascension, Livingston, East Feliciana, Ascension, Livingston, East Feliciana, St. St. Helena, Iberville, St. James, St. John, Iberville, St. James, St. John as well as 4 counties in Mississippi as well as 4 counties in Mississippi

- 20% of the basin lies in Mississippi- 20% of the basin lies in Mississippi

- 62% of the basin lies above Denham - 62% of the basin lies above Denham Springs Springs

- Only 7% of the basin is urbanized- Only 7% of the basin is urbanized  

1983 Flood1983 Flood Amite River Basin Amite River Basin

• The 1983 flood event was the flood ofThe 1983 flood event was the flood of record for most of the Amite River Basin. record for most of the Amite River Basin.

• It flooded over 357,000 acres and causedIt flooded over 357,000 acres and caused over $172 million in damages.over $172 million in damages.

• Significant flooding also occurred in ’73, Significant flooding also occurred in ’73, ’ ’77, ’79, ‘89, ‘90, and ’93.77, ’79, ‘89, ‘90, and ’93.

1983 Land Use Conditions in 1983 Land Use Conditions in Amite River Basin Amite River Basin

• Baton Rouge & Denham Springs area – Baton Rouge & Denham Springs area – urbanized – heavy flooding damages along urbanized – heavy flooding damages along tributariestributaries

• Amite RiverAmite River– North of Denham Springs – heavily forested North of Denham Springs – heavily forested

and agricultural areas floodedand agricultural areas flooded– South of Denham Springs – wide, wetland South of Denham Springs – wide, wetland

floodplains with small communities floodedfloodplains with small communities flooded• Comite River upstream of Baton Rouge – Comite River upstream of Baton Rouge –

heavily forested/agricultural use with small heavily forested/agricultural use with small communities developingcommunities developing

Legend

Headwater

Backwater

Denham Springs

Scotlandville

BatonBatonRougeRouge

Baker

Zachary

PortVincent

Co

mite R

iverC

om

ite River

Mississip

pi

Mississip

pi

Amite River

Amite River

Beaver B

ayou

Beaver B

ayou

#1#1

Amite

Jones CreekJones Creek

Bayou Fountain

Bayou Fountain

Bayou Bayou ManchacManchac

Dawson Creek

Dawson Creek

JonesJones

Tri

b.

Tri

b.

Liv

ely

B.

Liv

ely

B.

#2#2#1#1 #2#2

Weiner BWeiner B

Trib.Trib.

Clay Cut BayouClay Cut Bayou

North

BR.

North

BR.

War

dW

ard

Ward Creek

Ward Creek

Bla

ckw

ater

Bay

ou

Bla

ckw

ater

Bay

ou

RiverRiver

Causes and Types of FloodingCauses and Types of Flooding- There is no one solution in a 2,200 sq mi basin- There is no one solution in a 2,200 sq mi basin

- Three types of flooding must be addressed:- Three types of flooding must be addressed:

• Basin-wide floodingBasin-wide flooding associated with Amite associated with Amite River (headwater and backwater) River (headwater and backwater)• Headwater floodingHeadwater flooding (not assoc with Amite River) (not assoc with Amite River)• Backwater floodingBackwater flooding (not assoc with Amite River) (not assoc with Amite River)

- - Basin-wide floodingBasin-wide flooding occurs when a heavy rainfall occurs when a heavy rainfall occurs throughout the basinoccurs throughout the basin

- - Headwater floodingHeadwater flooding occurs in the upper reaches of occurs in the upper reaches of streams, usually caused by localized rainfall eventsstreams, usually caused by localized rainfall events

- - Backwater floodingBackwater flooding is caused when water backs up is caused when water backs up from the main waterwayfrom the main waterway

ExerciseExercise-As a team, using material from lectures and As a team, using material from lectures and notebook, and the watershed information provided:notebook, and the watershed information provided:

-Brainstorm potential flood damage reduction Brainstorm potential flood damage reduction measures that could be analyzed for the Amite measures that could be analyzed for the Amite River Watershed.River Watershed.

-Try to develop 2 or more alternative proposals for Try to develop 2 or more alternative proposals for the Amite River, the Comite River, and the the Amite River, the Comite River, and the tributariestributaries

-How will each potential alternative impact flooding How will each potential alternative impact flooding in the watershed?in the watershed?

-What additional issues (environmental, What additional issues (environmental, engineering, economics, etc) need to be engineering, economics, etc) need to be considered?considered?

Exercise Summary

• Each Team Present Their Conclusions from the Exercise