STATUS OF LOCAL COOPERATION: It is estimated that local interests had spent approximately $292,000,000 for flood protection After passage of the Act, the 37 levee districts along the Mississippi River adopted prior to the Act of 15 May 1928. These local interests have resolutions assuring the United States that the requirements of local cooperation will be met. acquired all rights-of-way for work completed and underway and will try to provide the rights-of-way for work scheduled for Some levee boards are having difficulty in providing rights-of-way when requested because of financial Fiscal Year 1993. problems, even for construction work in areas where the existing levees are furthest below the authorized grade. Supplemental assurances covering the requirements of the Uniform Relocations Assistance and Real Property Acquisition Policies Act of 1970 (PL 91-646) have been accepted for Main Stem Mississippi River Levees in Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. Assurances of local cooperation for the recreation facilities at Warfield Point, Mississippi, were accepted on 14 COMPARISON OF FEDERAL COST ESTIMATES: The current Federal cost estimate of $1,402,000,000 is an increase of $42,000,000 This change includes the following items: from the latest estimate ($1,360,000,000) presented to Congress (FY 1992). Design changes Post Contract Award and Other Estimating Adjustments Total STATUS OF ENVIRONMENTAL IMPACT STATEMENT: The Final Environmental Impact Statement was filed with the Council on OTHER INFORMATION: Initial construction funds were appropriated in Fiscal Year 1928. APPROPRIATION TITLE: Flood Control, Mississippi River and Tributaries, AR, IL, KY, LA, MS, MO and TN Construction PROJECT: Channel Improvement, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri and Tennessee (Continuing) LOCATION: The project is located in the Mississippi River and along its banks from the vicinity of Cairo, Illinois, to the Head of Passes, Louisiana, a distance of approximately 966 miles. DESCRIPTION: The plan of improvement consists of stabilizing the banks of the river in a desirable alignment and obtaining the most efficient flow characteristics for it for flood control and navigation by means of revetments, dikes, foreshore protection, and improvement dredging. All work is programmed. AUTHORIZATION: Flood Control Acts of 1928, 1936, 1938, 1941, 1944, 1962, 1965, 1966, and 1970. REMAINING BENEFIT-REMAINING COST RATIO: 31.2 to 1 at 2-1/2 percent. The benefit-cost ratio is based on all features which comprise the Main Stem system of the Mississippi River and Tributaries project. TOTAL BENEFIT-COST RATIO: 7.9 to 1 at 2-1/2 percent. INITIAL BENEFIT-COST RATIO: This project feature of the Main Stem system was authorized in Fiscal Year 1928 and initial construction funds were provided in Fiscal Year 1928. The authorized comprehensive review of the Mississippi River and Tributaries project, contained in House Document 308/88/2, as updated to reflect 1965 conditions and price levels, is considered to be the base estimate for the Main Stem system. The benefit-cost ratio for the Main Stem components computed for the base estimate was 7.9 to 1. BASIS OF BENEFIT-COST RATIO: Benefits are from the latest available evaluation approved in August 1991 at 1979 price levels. The latest comprehensive analysis was conducted in 1974. The 1979 analysis is the same as the 1974 analysis except that certain overall undocumented benefit categories were eliminated and 1979 prices were used. To use the 1974 analysis would have the effect of further increasing the benefit-cost ratio. JUSTIFICATION: The Channel Improvement Project is one of the Main Stem components which comprise the plan of improvement for the control of floods on the Mississippi River. The contribution of each element to the overall plan is inseparably related to that made by the others. Therefore, their benefits are inseparable and a composite benefit-cost ratio for the Main Stem components is necessary. The components are: Mississippi River Levees, Channel Improvement, South Bank Arkansas and South Bank Red River Levees, the Atchafalaya Basin, Atchafalaya Floodway System, Old River, and a few miscellaneous items. The Mississippi River, with a drainage area of about 1,245,000 square miles, has a wide range of flow, increasing from an approximate minimum of 90,000 cubic feet per second (675,000 gallons per second) to a maximum of 2,345,000 cubic feet per second (17,587,000 gallons per second) which occurred in 1927 at the latitude of Red River 1/ Reflects $6,490,000 reduction assigned as savings and slippage and $600,000 reprogrammed to the project.. The project flood is 3,030,000 cubic feet per second (22,500,000 gallons per second). Part of the tremendous Landing. energy of this volume of flowing water is directed toward a relentless attack on the banks of the river, causing the As this caving progresses, the attack becomes more direct, the bendway moves in unprotected banks to cave into the river. toward the levee, and more sediment is placed in the river and deposited downstream in the form of a sandbar. This bar gradually builds out into the channel and deflects the river's attack to the opposite bank. As the cycle is repeated the river tends to meander and lengthen. Revetment is placed against the banks of the river at locations where mainline levees are being threatened with destruction or where unsatisfactory alignment and channel conditions are developing. Revetment serves a three-fold purpose in that the river is prevented from encroaching on the Main Stem levees, excess material is kept out of the stream, and a favorable channel alignment and depth are maintained. An objective of the plan is to preserve favorable alignments and efficient cross-sectional areas and to prevent the river from creating new meander patterns. wide reaches of the river, dikes are used to contract the channel width so as to produce a single efficient channel for navigation and to insure the flood carrying capacity of the river. Chutes and secondary channels are closed for the same Improvement dredging is employed to assist the river in removing natural obstructions which deflect the current purpose. into undesirable patterns of flow and to assist in developing an efficient channel. Foreshore protection is utilized to preserve the integrity of the Mississippi River Levees from attack by erosion of the batture. Erosion of the batture leads to steep slopes which, when undermined, result in considerable loss of batture and possible failure of the levee. The area The value of lands and improvements protected by the Main Stem System authorized works against the design flood is $106.6 The maximum flood of record was the 1927 flood which overflowed about 26,000 square miles, caused the deaths of 214 people, rendered 637,000 people temporarily homeless, and caused property damages of $236.3 million. This would be equivalent to $4.2 billion in damages in 1991 prices. The next flood of magnitude was the 1973 flood which overflowed 16,875 square miles (10.8 million acres), caused the The benefit-cost ratio for the Main Stem System was derived by measuring the total benefits credited to those Main Stem components against their total cost. Average annual benefits for the composite of Main Stem features are as follows: FISCAL YEAR 1993: Revetments: The planned program consists of items of work for which funds will be required as follows: |