« PreviousContinue »
high water, however, has given rise to the suspicion that grades may have to be raised throughout a part of the reach. Studies are currently in progress to determine this.
The plan divorces the old Coldwater River from the present stream and requires its diversion, together with local drainage, through Cassidy Bayou. The improvement of the bayou, which is completed except for removal of a plug near its junction with old Coldwater River, has entailed about 45 miles of clearing, 19 miles of enlargements, four cut-offs, and two floodgates. The plug at old Coldwater River will be removed as soon as the divorcement of that stream is effected. The plan has also involved about 4 miles of clearing, 3 miles of enlargement, and 13 cut-offs on Bobo Bayou. The guide levees of the PanolaQuitman floodway require enlargement aggregating about 27 miles, and study is being given to the provision of protection works for the city of Greenwood at a cost of about $2,400,000.
From Greenwood to Yazoo City, where the headwater project ends, levee enlargement or construction of about 150 miles of levees, 13 floodgates, a pumping plant at Yazoo City, and 22 miles of ditches to handle interrupted drainage are required. This levee work will be initiated but not completed or fully effective until the Enid and Grenada Reservoirs are operative. A cut-off in Tchula Lake is also required. The cost to complete the project, exclusive of any adjustments found necessary, is estimated at $46,300,000. It must be realized that in such a comprehensive and involved project as this, which includes practically all known flood-control measures, minor modifications involving channel improvements and revamped levee grades may be necessary as various portions of the project are observed under flood conditions.
The flood of this winter brought water within 2.4 feet of the spillway crest of Arkabutla Dam. While the pool was at this high level, strong winds resulted in considerable wave-wash damage to the embankments of the highways crossing Arkabutla Reservoir. Highway No. 51 is carried on a rolled fill embankment with 1-on-3 side slopes, spot sodded. The embankment having been completed, the sod was in no condition to withstand the waves, which probably attained heights of about 8 feet. As a result the fill was “benched” quite badly in some spots. One of the main causes for the damage was the exposure of the fill resulting from the clearing of all timber adjacent to it at the behest of the State sanitary commission. We obtained release from the State highway department when the road was turned over to them, but they commented at the time on its vulnerability due to exposure and reserved the right to try to work something out with us if damage resulted from early floods. We have discussed the results of this year's flood with them and both they and we have come to the conclusion that the proper course is for us to restore and resod the embankment where damaged, just as we do in the case of a levee which is damaged before the sod has formed even though it may have been turned over to local interests in good condition, and for them to induce or encourage a fringe of timber on each side of the embankment to protect it against wave wash. We have agreed to drain pockets in this timber belt which might otherwise pond water and encourage mosquito production. If a high pool combined with a high wind should recur before the shelterbelt becomes effective, we shall probably have to repeat the repairs. We also have in mind, with the highway department's permission, the
possible installation of some stretches of experimental wave-wash protection which we should like to study in connection with earth-dam construction.
The wave damage was not confined to Highway No. 51 but also damaged the county roads crossing the reservoir from Coldwater to Arkabutla in Tate County and from Hernando to Eudora in De Soto County. The Government had had nothing to do with the construction of these roads, but had merely purchased releases from damages from the two counties. The payments were based on estimates of raising the two roadways, with their existing 1-on-2 side slopes, to spillway crest elevation. The counties appear not to have carried the fills quite as high as planned, and to have used rather steep side slopes, all of which may have contributed to the damage. However, they are exposed to a long expanse of lake by the removal of timber and it is believed only equitable that the Government should see the counties whole in the premises which was the original intent. The unprotected fresh embankments could not possibly have withstood the pounding to which the early occurrence of the high pool subjected them. Pavement of slopes with riprap would be prohibitively costly. It is believed, however, that the crossings should be constructed to proper grade, and sodded, and that the growth of tree belts should be encouraged for slope protection. The cost of treating the HernandoEudora Road in De Soto County is estimated at $242,500 and of treating the Coldwater-Arkabutla Road in Tate County, at $222,000. In both cases it is felt that if serious damage should recur before the shelterbelts afford relief, the roads should again be repaired at Federal expense. Since the Government did not build the roads, and did purchase an unequivocal quitclaim from the counties, it is felt that congressional authorization of the proposed action is necessary.
tal at elevat ity. The hunction with the River
The Flood Control Act of August 18, 1941, authorized the protection of the Yazoo backwater area to a grade 1 foot below the flow line of the record flood (1927) confined. This grade corresponds to 5612 feet on the United States engineer gage at Vicksburg. The protection is to be afforded by continuing the Mississippi River levee along the west bank of the Yazoo to a junction with the headwater project levee near Yazoo City. The grade of the backwater levee will be horizontal at elevation 103.7 mean sea level from the Missisippi River levee to the mouth of Big Sunflower River. This will be the fuse-plug portion. It will be overtopped at average intervals of 31 years. From that point upstream the grade will rise so that the area will not be inundated by floods of the Yazoo River which meet Mississippi River floods whose height does not require inundation of the backwater area.
The backwater levee will intercept all drainage west of the Yazoo, from an area of approximately 4,400 square miles. Pumping plants and floodgates will be provided where the levee crosses the main streams-Sunflower River, Steele Bayou, and Deer Creek, and drainage will be conducted to these points in part by landside borrow pits and in part by excavated drainage canals. A floodgate will also be provided where the levee crosses Little Sunflower River. The pumps
rega (Roleted above tad is a probably inline arena
poo give it prou) to the area. tump area.
Lin Pasite. The estection equal to of the Yazes
and floodgates are expected to prevent water levels rising above elevation 90 mean sea level at intervals of less than 5 years. The area below contour 90, or 125,000 acres, is considered as probably inundated too frequently to be profitably cultivated and is called the sump area. There are 634,000 acres benefited above the sump area. The levees of the small leveed area (Rocky Bayou) to the east of the Yazoo River will be raised so as to give it protection equal to that afforded by the west bank levee opposite. The estimated cost of the backwater project as authorized in 1941 is $11,982,000.
The Flood Control Act of December 22, 1944, authorized the Chief of Engineers in his discretion, to include in the Yazoo backwater project, improvements for the protection of the Satartia area at an estimated additional cost of $1,061,000 or in his discretion, to include improvements for the protection of the Satartia area plus its extension at an estimated additional cost of $1,952,000.
The Satartia area embraces some 26,700 acres, of which 23,800 would be protected, lying just below Satartia, Miss. The Satartia area extended includes an additional 4,500 acres of which 3,300 would be protected, lying east of the Yazoo just below the larger Satartia area. Surveys looking toward a detailed location for the backwater levees will be started in June, and studies will be made at that time with a view to deciding upon whether it is desirable to include the Satartia extension or to include the main area only.
LOWER YAZOO TRIBUTARIES
The Flood Control Act of December 22, 1944, authorized also for the Yazoo Basin, at an estimated cost of $3,752,000, the project for flood control on the Big Sunflower, Little Sunflower, Hushpuckena, and Quiver Rivers and their tributaries, and on Hull Brake-Mill Creek Canal, Bogue Phalia, Ditchlow Bayou, Deer Creek, and Steele Bayou in accordance with the recommendations of the Chief of Engineers in House Docket 516, Seventy-eighth Congress, second session. Based on current prices it is estimated that approximately $5,000,000 will be required to accomplish the work outlined in the original authorization.
The streams included are the west bank tributaries of the Yazoo system whose overflows menace the lands protected against the Mississippi and the Yazoo Rivers proper. The channels of these streams have deteriorated from willow growth, and the deposition of timber slashings, et cetera. They drain the basin east of the Mississippi River and west of Cassidy Bayou and the Tallahatchie-Yazoo Rivers from near Clarksdale, Miss., to near Vicksburg. The basin averages about 30 miles in width and is about 140 miles long, with an area of 4,200 square miles. A number of drainage canals have been constructed but they are ineffective at times because of the choked conditions of the streams which provide the outfall drainage. Annual damages that would result from overflows caused by the poor condition of the stream channels after completion of the Yazoo headwater proj. ect are estimated at about $13,000. The design of the project is to provide channel capacity to the several streams equal to the design flows generally used in standard practice for agricultural drainage in the territory. This standard contemplates a run-off of 1.3 inches in 24 hours from a square mile, or 0.6 inches from 100 square miles, or
1/2 inch from 500 square miles. This corresponds to about a 4inch isolated rain in 24 hours or 7 inches in a week.
The plan is to improve Big Sunflower River practically throughout and Hull-Brake-Mill Creek Canal throughout, by snagging, clearing and snagging, or channel enlargement as the several reaches require. The other tributaries of the Sunflower to be improved are Hushpuckena River, Bogue Phalia, Quiver River, and Ditchlow Bayou. In addition, Steel Bayou, Deer Creek, and Little Sunflower River are to be improved.
Hushpuckena is to be improved between miles 14 and 17 by clearing and snagging and between miles 17 and 27 by enlargement. Quiver River is to be cleared and snagged between miles 55 and 65. Below mile 55 it was previously cleared and snagged under authority contained in section 2 of the act of August 28, 1937. This stretch has since grown up and should be included in the project for reclearing and snagging at an estimated cost of about $83,000. The improvement of Bogue Phalia is to comprise channel enlargement from mile 6 to mile 20 and from mile 29 to mile 45. Visual inspection indicates that the other reaches of this stream are adequate but its entire course is being surveyed and if the survey discloses that additional improvements are necessary to the realization of anticipated benefits from the project, they should, of course, be made. Ditchlow Bayou is to be enlarged for 4 miles at the lower end. On Little Sunflower River the improvement consists of snagging the lower 13 miles and clearing and snagging the remainder. The only improvement presently planned for Deer Creek is intermittent enlargement between miles 1531/2 and 160. On Steele Bayou the lower 66 miles are to be improved by 46 miles of clearing and 20 miles of intermittent enlargement, and the upper 4 miles are to be enlarged between lake sections.
The precise nature and extent of any additional work needed cannot be forecast at this time. The data are still far from complete. It is believed, however, that if the project were considered a part of the Yazoo Basin plans of the project “Flood Control, Mississippi River and Tributaries,” such modifications as appeared necessary could be made without requiring specific Congressional action since they would be within the scope of the plain intent of the act, and in a project so large as the Mississippi River flood-control project funds can usually be made available for minor increases in cost by modifications or savings in connection with other features of the project. By implication, it is a part of the Mississippi River project because the congressional resolution authorizing its consideration was one calling for a review of the report on Yazoo River—House Document No. 198, Seventy-third Congress, second session—which forms the basis for the Yazoo headwater and backwater projects; of which the project under discussion constitutes a modification. It is not specifically designated in the 1944 act, however, as a part of the main project. It would appear desirable to make it specifically a part of the main project and subject to such modification as, in the discretion of the Chief of Engineers, the development of more complete data may indicate to be necessary to effectuate the purpose of the plan.
The deficiency act provided $200,000 for planning in connection with this project and surveys have been in progress for some time. No construction funds have been made available.
BOEUF AND TENSAS RIVERS AND BAYOU MACON
The 1944 flood-control act also authorized the project for flood control on the Boeuf and Tensas Rivers and Bayou Macon, Arkansas and Louisiana, in consonance with the plan recommended by the Chief of Engineers in House Document No. 151, Seventy-eighth Congress, second session, at an estimated cost of $5,013,000. Based on current prices it is estimated that approximately $7,000,000 will be required to accomplish the works outlined in the original authorization.
This project is in many respects quite similar to that just described on the other side of the river. The streams named occupy contiguous watersheds and flow generally parallel to the Mississippi River to drain a basin about 28 miles wide and 190 miles long containing 5,280 square miles, 1,350 in Arkansas and 3,930 in Louisiana, lying between the Mississippi River and Bayou Bartholomew. There are about 208,400 acres subject to overflow along the Boeuf above Bayou Lafourche, 115,000 in Arkansas, and 93,400 in Louisiana; about 129,400 acres along Big Creek-Colewa Creek and Colewa Bayou, principal tributary of Boeuf River, above 65,000 acres along Tensas River, and 31,000 acres along Bayou Macon. Average annual flood damages are estimated at $94,200.
There used to be an opening in the Mississippi River levee known as the Cypress Creek gap near the Arkansas River, through which the drainage of the Cypress Creek Basin—430 square miles—was evacuated. Local interests in Arkansas diverted this drainage to Boeuf River and Bayou Macon and the gap was closed in December 1920. The upper part of Bayou Macon, and Boeuf River to the State line were improved but the improvement did not extend into Louisiana. The result was impaired usefulness of the extensive system of canals and improved channels in Arkansas and increased flooding in Louisiana due to improved run-off from above.
The plan now approved is to realine and enlarge Boeuf River from the head of Bayou Lafourche to the Arkansas State line; to clear and snag, and enlarge where needed, its principal tributary Big CreekColewa Creek-Colewa Bayou; to clear and snag Bayou Macon from its mouth to Eudora, Ark., to block off several of its outlets into Lake Providence, and to clear and snag Tensas River from its mouth to mile 146 and enlarge it from that point upstream for about 14 miles. The deficiency bill provided $164,000 for planning, and surveys are under way.
RED RIVER BACKWATER AREA The Flood Control Act of August 18, 1941, authorized as part of the project, “Flood control, Mississippi River and tributaries,” the protection of that part of the Red River backwater known as the TensasCocodrie area at an estimated cost of $6,976,000, in conformity with plans presented in the report of the Mississippi River Commission dated March 7, 1941; it also authorized the Chief of Engineers in his discretion to substitute other levees and appurtenant works for, or make such modification of, the levees and improvements authorized as may be found after further investigation to afford protection to a larger area in the Red River backwater at a total cost not to exceed