Army Corps of Engineers Comite River Diversion Project Website

 

PROJECT FACT SHEET

Comite River Diversion Canal Project

(CRDC)

 

General

 

The Amite River and its tributary the Comite River are the major causes of catastrophic flooding in the Baton Rouge Metropolitan Area. The flood of record occurred in 1983 when a substantial portion of East Baton Rouge, Livingston and Ascension Parishes were inundated. This precipitated an interest and action on the part of federal, state and local authorities to find solutions to this problem. It was recognized that major floods caused by the Amite and Comite Rivers could not be solved locally and that it required a basin wide/regional solution. This resulted in a series of studies by the U.S. Army Corps of Engineers (USACE) under the congressionally approved Amite River & Tributaries Study Authority.

The Comite River Diversion Canal Project evolved through this process and in the year 2000 the citizens of the benefit area of the project-Taxing District- approved by a 2/3 majority a 10-year, 3 mill Ad-Valorem tax to provide for part of the non-federal match. Subsequently a Project Cooperative Agreement between the USACE, State, ARBC and East Baton Rouge Parish was signed on October 1, 2001 to begin construction of the project.

The purpose of the Comite River Diversion Canal Project is to divert flood waters from the Upper Comite River to the Mississippi River. At its capacity the project will divert 20,000 cubic feet per second; this represents approximately 50% of the flood waters from the upper Comite River and approximately 2% of the Mississippi River at the discharge location. See plate 1.

The Baton Rouge Metropolitan Area has experienced an explosive population growth in recent years primarily as a consequence of the population displacement from the New Orleans area after Hurricane Katrina, giving this flood control amelioration project an even more important and urgent significance.

 

Authority


The authorities for the Comite River Diversion Channel Project are the Water Resources Development Act (WRDA) of 1986 Public Law (PL) 99-662, which established the cost sharing principles for the project, section 101(11) WRDA of 1992, PL 102-580, dated October 31, 1992 (WRDA 1992), as amended and reauthorized by Section 301(b)(5) of the WRDA 1996, PL 104-303 dated October 12, 1996, and as amended by Section 371 of WRDA 1999, PL 106-53 dated August 1999, with technical corrections to Section 371 of WRDA 1999 in Section 6 of PL 106-109 dated November 24, 1999, which is the main project authorization. The Water Resources Development Act (WRDA) of 1986, established the cost sharing for the project. The non-Federal cost shall include a mandatory 5% cost contribution, the purchase of all lands, easements, rights-of-way, relocations and disposal areas (LERRD's). The law also established that the non-Federal cost at a minimum of 25% and a maximum of 50% of the total cost. Section 37 of WRDA 1999 further modified cost sharing for the Comite Project to include the cost of highway relocations as a cost shared feature.

 

Scope

 

The authorized project provided for construction of a 12 mile long diversion channel from the Comite River to the Mississippi River, a diversion structure at the Comite River, guide levees, Lilly Bayou control structure, four drop structures at the intersections of the diversion channel with McHugh Road, Bayou Baton Rouge, Cypress Bayou, and White Bayou, and Highway and Railroad Bridges. Low-flow augmentation pumps at the intercepted streams and an earthen closure at Brooks Lake, clearing and snagging of Bayou Baton Rouge, White Bayou and Cypress Bayou north of the diversion channel to reduce flooding in those areas. (see Army Corps of Engineers Comite River Diversion Canal Project Website)

 

Estimated Cost (2008)

            Federal                                                 $134,000,000

Non-Federal                                             $ 53,000,000

State (LADOTD)                                    $ 43,000,000

ARBC                            $ 10,000,000

Total                                                   $187,000,000

 

U.S. Army Corps of Engineers Capability for F.Y. 2008

 

The capability of the US Army Corps of Engineers for the Comite River Diversion Canal Project for F.Y. 2008 is $18,000,000.

 

Estimated Project Benefit

 

The CRDC Project has an estimate Cost-Benefit ratio of 2.3. Once completed, the project will reduce flooding stages substantially in East Baton Rouge, Livingston and Ascension Parishes.

 

Average annual savings to a homeowner for a Flood Insurance Policy as a result of the lowering of the flood stages:

 

Pre-Firm Homes benefiting from flood stage lowerings with finished floor elevation below the BFE*(+/- 2ft.)

Insured market value

of home

Savings in

annual premium

Cost of a

3-mill tax

Net annual savings to homeowner

 

$100,000

 

$224 - $351

 

$7.50

 

$216.50 $343.50

 

$150,000

 

$284 - $411

 

$22.50

 

$261.50 - $388.50

 

$200,000

 

$343 - $470

 

$37.50

 

$305.50 - $432.50

 

$250,000

 

$392 - $519

 

$52.50

 

$339.50 - $466.50

*BFE = Base Flood Elevation (100-year flood elevation)

Pre-firm homes: Homes built before FEMA regulations came into effect

 

Estimated flood stage reductions during last six major floods if project would have been in place:

Date Estimated Flood Stage Reduction

 

 

Comite River @ Comite, LA (Joor)

 

Amite River @ Denham Springs

 

 

April 1977

4.3 ft.

1.5 ft.

April 1979

4.5 ft.

1.5 ft.

April 1983

4.0 ft.

1.4 ft.

January 1990

4.5 ft.

1.5 ft.

January 1993

4.3 ft.

1.5 ft.

January 1994

4.5 ft.

1.5 ft.

 

Expected future stage lowerings with project in place:

Comite River at White Bayou

10 year flood 6.2 feet lower

25 year flood 6.1 feet lower

50 year flood 6.3 feet lower

100 year flood 6.2 feet lower

 

Comite River at Hooper Road

10 year flood 6.0 feet lower

25 year flood 5.7 feet lower

50 year flood 5.1 feet lower

100 year flood 4.4 feet lower

Comite River at Comite. LA. (Joor Rd)

10 year flood 4.8 feet lower

25 year flood 4.8 feet lower

50 year flood 4.3 feet lower

100 year flood 3.8 feet lower

 

Comite River at Hurricane Creek

10 year flood 4.2 feet lower

25 year flood 4.4 feet lower

50 year flood 4.1 feet lower

100 year flood 4.1 feet lower

 

Amite River at Denham Springs

10 year flood 1.5 feet lower

25 year flood 1.5 feet lower

50 year flood 1.4 feet lower

100 year flood 1.2 feet lower

 

Amite River at Port Vincent

10 year flood 0.8 feet lower

25 year flood 0.7 feet lower

50 year flood 0.6 feet lower

100 year flood 0.6 feet lower

 

 

Source of Non-Federal Funds

 

The non-federal sponsors for construction of the project are the LADOTD and the ARBC.

State funds are obtained through annual appropriations through the State Capital Outlay Program and the ARBC funds are obtained through a 10-year, 3 mil Ad-Valorem tax of properties located within the benefit area of the project.

 

Once completed, the CRDC will be maintained by local governments within the District.

 

Estimated Construction Schedule

 

Due to funding delays the project construction schedule had to be extended to the year 2016.

 

Construction Progress to Date

 

The following is the status of the construction as of March 2008.

Construction of the Lilly Bayou Control Structure is expected to be completed by the end of 2008. This is the largest structure of the project at a cost of $35,000,000.

 

U.S. Hwy 67 Bridge, (Plank Road), is expected to begin construction at the end of 2008 or beginning of 2009.

 

Real Estate acquisitions have been completed for a large portion of the west end of the channel. As of March 2008, 400 acres have been acquired. This represents approximately 20% of the total right-of-way needed for the project.

 

Also, right-of-ways are being acquired for the U.S. Hwy 67 Bridge and necessary mitigation areas along the Comite River north of the CRDC.