Chapter 10: Middle Missouri River Basin The Missouri River Region, the largest of the Nation's 18 major regions, embraces 513,000 square miles within all or part of 10 states. Because it is too big and varied to be treated as a single unit, the Missouri River Region has been divided into eight basins identified as the Upper Missouri, the Yellowstone, the Western Dakota, the Eastern Dakota, the Platte-Niobrara, the Middle Missouri, the Kansas River, and the Lower Missouri. Three of these basins, the Middle Missouri, the Eastern Dakota, and the Lower Missouri, include portions of Iowa. As the map of the Middle Missouri River Basin shows, the Eastern Dakota basin includes only a small portion of Iowa and is not commented on separately in this booklet. The Middle Missouri, the smallest of the eight basins, encompasses 24,600 square miles. The bulk of the basin lies in extreme western Iowa. With 76 percent of the land under cultivation, soil erosion is a major problem. Several large and growing urban centers in Omaha, Neb.; Sioux City and Council Bluffs, Iowa; Atchison and Leavenworth, Kan.; and St. Joseph, Mo., meet their water needs from the Missouri River. In the past, before the era of the comprehensive Pick-Sloan plan for water resources development, these cities were subject to the onslaught of uncontrolled floods on the Missouri and its tributaries. Today, dams, floodwalls, levees, and other projects built by the Corps of Engineers protect these centers of population against the tragedy of destructive floods. The rich agricultural bottom lands that border the Missouri also benefit from the system of levees which stretch from Council Bluffs south to the Iowa-Missouri state line and beyond. Flood Control Floyd River, Sioux City Completed Project, Local Protection (Omaha District) This project, authorized by the Flood Control Act of 1958, is designed to protect highly developed commercial, industrial, and residential areas located in the Floyd River flood plain in Sioux City. The Floyd River at Sioux City had a history of severe floods that culminated in the disastrous 1953 flood which caused more than $23 million in damage and the loss of 14 lives. Construction was started in 1961 and completed in 1966. The project consists of channel straightening and enlargement, earth levees, and extensive construction or modification of a number of streets, railroad bridges, and utilities. Cost of the project was $18,356,700, including $5.8 million borne by local interests. Damages prevented by this project since its completion are estimated to be $27,441,000. The city of Sioux City operates and maintains the project. Little Sioux River Basin Completed Project, Local Protection (Omaha District) This project was authorized by the Flood Control Act of 1954. It is designed to protect approximately 188,000 acres of highly productive farmland and several small communities located along the Little Sioux River from its mouth to the town of Smithland. The project consists of approximately 62 miles of channel improvement and enlargement, 138 miles of levee with an average height of 12 feet, tiebacks, drainage structures, and a large diversion channel between the Little Sioux River and the Monona-Harrison Ditch. Construction was started in 1956 and completed in 1966. Since 1959, when the project became partially operational, it has prevented flood damages estimated at more than $164,980,000. The project cost was $18,483,000, including a $3 million non-federal cost. Local interests operate and maintain the project. In the early 1960's, the lower four to five miles of the project were adversely affected by channel erosion. Because of this, a bed-grade control structure, now known as Sill No. 4, was constructed immediately downstream from the Monona- Harrison County line. Sill No. 4 was constructed during the winter of 1964-65. Because of damage caused by high flows in the basin, several rehabilitation contracts were required from 1965 to 1982. In March 1983, the right-bank wingwall of the drop structure was overcome by high water flowing down the Little Sioux River. Severe damage resulted to not only the structure but also to the right-bank berm and levee. Emergency contracts were awarded to riprap the permanent levee in order to prevent failure from occurring immediately downstream from the structure. In late 1983 and early in 1984, a new structure was designed and modeled at the U.S. Army Engineer Waterways Experiment Station. A new contract was awarded for Sill No. 4 that replaced the original bed-grade control structure at a cost of approximately $4,262,500. The work was completed in January 1986. Since construction, two repair contracts have been necessary—one to armor the notches in 1988 and another to repair an erosion area downstream from the structure in 1989. The Iowa Department of Natural Resources (IDNR) recently completed an evaluation of Sill No. 4 for fish passage capability. The sill was designed with a low-flow notch so that large Missouri River catfish could have access to old spawning grounds in the excellent habitat afforded by the Little Sioux River. During the summer of 1986, the IDNR captured and tagged 6,841 channel catfish at locations both upstream and downstream from the sill. The results indicated that fish were over five times more abundant upstream and downstream from the sill, and that only two of the fish tagged downstream from the sill were recaptured upstream from the sill. These data indicate that the sill was ineffective for fish passage under conditions experienced in the study. The poor performance is believed to be caused by an erosion protection barrier placed at the bottom of the notch. Field surveys of the channel area immediately upstream from Sill No. 4 have been conducted. An assessment of the impact of silt and trash accumulation on fish passage and river stages upstream from the structure is currently being conducted. If the results of these studies indicate that silt and trash accumulation has eliminated fish passage and caused an unacceptable increase in upstream river stages, temporarily removing the stop logs in the two higher sills and installing the stop logs in the low sill may be considered. The purpose of this action would be to determine if forcing more flow over the higher sills would reduce or eliminate the problem of debris accumulation. If that is successful, then alternative methods of fish passage would be investigated. Maple River and Odebolt Creek, Ida Grove Completed Project, Local Protection (Omaha District) A portion of the town of Ida Grove containing municipal, commercial, and residential developments is subject to recurring flood damage from the overflows of both the Maple River and Odebolt Creek. The authorized plan for alleviation of the flood problem at Ida Grove consists of channel improvement and realignment and levees along both Maple River and Odebolt Creek. Construction of the project was started in 1968 and completed in 1970. Project costs were $541,300, including a $19,000 non-federal cost. The project has prevented more than $855,000 in flood damages through fiscal year 1994. Local interests operate and maintain the project. Nishnabotna River, Hamburg Completed Project, Local Protection (Omaha District) This project, completed in 1947, provides flood protection for the town of Hamburg. It consists essentially of 1,800 feet of channel straightening and approximately two miles of levee along the Nishnabotna River. The project joins Missouri River Levee System Unit L-575 south of Hamburg and is an integral part of the Missouri River Levee System. During extremely severe flooding in 1984, the project prevented an estimated $7,020,000 in damages. Since its completion, the project is credited with preventing $112,124,500 in flood damages. Cost of the project was $262,000, of which $26,000 was assumed by local interests. Local interests operate and maintain the project. In 1990, the Omaha District completed a reconnaissance-level reevaluation of the levee protecting Hamburg. The study concluded that it would be feasible to raise the existing Nishnabotna River levee to provide the 100-year level of protection plus three feet of freeboard. The study also concluded that it would be feasible to construct a levee west of Hamburg to protect the city from flooding along Ditch 6. The estimated cost to construct these improvements is about $2.5 million. A cost- shared feasibility-level study was initiated in August 1992 and is scheduled for completion in mid-1994. The city of Hamburg is the non-federal sponsor for this study. East Nishnabotna River, Red Oak Completed Project, Local Protection (Omaha District) A local protection project consisting of a levee and appurtenant works on the left bank of the East Nishnabotna River was completed in 1962. The project was built to provide the city of Red Oak with protection against such disastrous floods as those that occurred in 1947 and 1958; losses from those floods were over $1 million. The project, designed to contain floods approximately 1.5 times greater than the maximum historical flood, also minimizes the threat to lives of the residents. Past floods have resulted in several drownings in the Nishnabotna River. In 1972, the project was credited with preventing an estimated $2.4 million in flood damages. Cost of the project was $443,000, including $43,000 in non-federal costs. Local interests operate and maintain the project. Flooding subsequent to completion of the project raised concerns about its adequacy. A study was made under the authority of Section 205 of the Flood Control Act of 1948, as amended, and the recommendation to raise the existing project to standard project flood protection was approved in February 1981. Construction was completed under Section 205 authority in July 1983. The total project cost (including the cost of the original project) was $2.3 million, of which $2,157,000 was federal and $143,000 was non-federal. Local interests operate and maintain the project. Total damages prevented by the project through September 1994 are estimated at $10,000,800. Big Sioux River, Sioux City, Iowa, and North Sioux City, South Dakota Completed Project, Local Protection (Omaha District) The Flood Control Act of 1968 authorized a project for improving the Big Sioux River channel from its mouth near Sioux City, Iowa, to a point 5.5 miles upstream. In April 1969, a flood on the Big Sioux River from snowmelt run-off caused approximatly $3 million in damages at 1975 price levels in North Sioux City and Sioux City. Postauthorization reformulation studies developed a plan of improvement that deviated somewhat from the plan as originally authorized. Improvements consist of channel enlargement, bank stabilization, and levees to protect some 1,600 acres from a standard project flood event. A channel relocation at the mouth of the Big Sioux River was dropped from the plan for economic reasons. The federal cost of the project was $7,758,000 and the non-federal cost was $525,000. Project construction was initiated in September 1976 and completed in September 1981. Flood damages prevented by the project through September 1994 totaled $102,100. Indian Creek, Emerson Completed Project, Section 205 (Omaha District) In June 1982, Indian Creek flooded businesses and homes in Emerson, causing more than $2.5 million in damages. A local protection project on Indian Creek at Emerson was approved for construction in May 1983 under the provisions of Section 205 of the Flood Control Act of 1948, as amended. The project consists of a short levee and appurtenant works on the right bank of Indian Creek on the east edge of Emerson and a flood warning system. The levee is approximately 180 feet long and averages 8.5 feet in height. The project provides standard project flood protection with three feet of freeboard. Completed in 1984, the project cost was $333,000 (federal cost). No flood damages have been prevented by the project through September 1994. Dry Creek, Hawarden Completed Project, Section 205 (Omaha District) Construction of a leveed diversion channel to divert floodflows on Dry Creek south of the town of Hawarden was started in 1962 and completed in 1963 under the provisions of Section 205 of the Flood Control Act of 1948, as amended. The project protects the main business district and a large residential area of Hawarden. Cost of the project was $500,134, including $100,135 in non-federal funds. Through September 1994, the project has prevented an estimated $552,000 in flood damages. Local interests operate and maintain the project. Indian Creek at Hastings Ongoing Project, Section 205 (Omaha District) Feasibility studies were initiated in November 1989. The studies show that it would be feasible to construct a 100-year levee on Indian Creek at Hastings at an estimated cost of $200,000. The city of Hastings is currently considering whether it will cost-share the construction of the project. Perry Creek, Sioux City Project Underway, Local Protection (Omaha District) Congress authorized the Perry Creek project in the Water Resources Development Act of 1986 (Public Law 99-662). The project will consist of channel and conduit modifications sized to provide protection from floods up to the 100-year flood event. The project is currently in the design stage. Construction is scheduled to begin in fiscal year 1995 and is scheduled for completion in fiscal year 2000. When completed, the project will provide protection to over 1,800 homes and businesses. Davids Creek Dam and Lake DeauthorizedProject, Reservoir (Omaha District) The Davids Creek Dam and Lake is a unit in the flood control and water resources development plan for the Nishnabotna River Basin. The plan for the Davids Creek project was approved in the Flood Control Act of 1968. The dam would be located on Davids Creek, a left bank tributary of the East Nishnabotna River, about one- half mile upstream from the town of Exira, Iowa. The rolled earth dam would be 1,800 feet long, would rise to a height of 62 feet above the creek bed, and would control the runoff from a drainage area of more than 60 square miles. The lake would have a storage capacity of 60,000 acre-feet at maximum pool level, of which 21,100 acre-feet would be allocated to flood control storage. The project was deauthorized by the Water Resource Development Act of 1986 (Public Law 99-662). Lower Big Sioux River and Tributaries, Iowa and South Dakota Deauthorized Project, Local Protection (Omaha District) The Flood Control Act of 1965 authorized a project for improving the lower Big Sioux River channel from its mouth near Sioux City to a point approximately two miles north of Akron, Iowa. Improvements would consist of channel cutoffs and cleaning, deepening, and enlarging the existing channel where necessary. The lower 5.5 miles of this project were deauthorized by the Flood Control Act of 1968. The improvements for this reach of the river are contained in the project for the Big Sioux River at Sioux City, Iowa, and North Sioux City, S.D., described elsewhere in this booklet. The remainder of the project was recommended for deauthorization in 1975 and was deauthorized by Congress in December 1989. Thurman to Hamburg, Iowa Project Underway, Local Protection (Omaha District) This study was authorized by the Water Resources Development Act of 1986 to study measures to prevent flooding in western Fremont County. In 1990, a reconnaissance study was completed which concluded that flooding problems can be attributed to high flows on the Missouri River, which prevents the drainage through levee Unit L-575. A feasibility study was initiated in February 1992 to determine the feasibility of pumps at two locations draining a total of more than 40,000 acres of agricultural lands. Fremont County, Iowa, is the project sponsor. The feasibility study was completed in March 1994. Installation of the pumps is scheduled to be completed in December 1995. The Corps is currently conducting a $379,000 cost-shared feasibility study under the Section 205 authority. A levee west of Hamburg, which will protect the city from flooding by Ditch 6, has been identified as economically feasible. Completion of the study is scheduled for October 1995. Eastern South Dakota and Upper Big Sioux River, South Dakota and Iowa Study Completed (Omaha District) The study, which responded to five congressional resolutions, examined the need for flood control east of the Missouri River in South Dakota and in the Big Sioux River basin in Iowa. The study findings were reported in the Eastern South Dakota and Upper Big Sioux Rivers, South Dakota and Iowa Report, dated February 1989. The study did not identify any feasible flood control measures for the Big Sioux River basin in Iowa. As part of this study, reconnaissance reports for flood control for Watertown and Sioux Falls in South Dakota were completed, leading to cost-shared feasibility studies that began in February 1991. An initial review of the flooding problems in the James River basin was completed. The James River Reconnaissance Study continued this review. Early in the study process, a major effort was devoted to water supply and water quality in the study area. Subsequent changes in the Corps of Engineers policy required a major reduction in the scope of these studies. The principal finding of the water supply studies is included in the 1989 report. Water Resources Development Iowa Section 22 Studies (Omaha District) The Planning Assistance to States Program was authorized by Section 22 of the Water Resources Development Act of 1974 (Public Law 93-251), as amended. The Section 22 program was established by Congress to enable states to utilize Corps of Engineers planning expertise in the preparation of comprehensive plans for the development, utilization, and conservation of the water and related land resources of drainage basins located within the boundaries of a state. The assistance can be provided to any public entity as long as it is consistent with the state's water resources planning objective. The priority of the work is established by the state. The Omaha, Rock Island, St. Paul, and Kansas City Districts serve the state of Iowa. The Rock Island District has been designated as the lead district for the Section 22 program in Iowa. The Water Resources Development Act of 1990 requires that the program be cost-shared between the Corps of Engineers and a non- federal public entity. Work during 1989 and 1990 involved the continuation and completion of the Nishnabotna River floodway analysis, which was initiated during 1984. Fiscal year 1989 work consisted of gathering cross sections along the West Nishnabotna River from north of Riverton to the Fremont County line. Fiscal year 1990 work included an analysis of the floodway and flood boundaries from the confluence of the East and West Nishnabotna rivers to the Fremont County line. Fiscal year 1994 work involved a 50-50 cost share study with the city of Atlantic. The study, conducted by the Omaha District, identified flood control alternatives for Bull Creek in Atlantic. Proposed fiscal year 1995 work includes a future management plan for the Iowa Great Lakes. Navigation Projects Middle Missouri River Basin Completed Project, Missouri River Navigation and Erosion Control Project, Sioux City, Iowa, toFort Benton, Mont. Omaha District) The removal of snags and rocks from the Missouri River channel was one of the earliest functions of the Corps of Engineers in the Missouri River basin, dating back to the steamboating days of the last century. This work accomplished much for early traffic on the river. In July 1912, Congress enacted a River and Harbor Act which included a project known as the Missouri River Navigation and Erosion Control Project, Sioux City, Iowa, to Fort Benton, Montana. It provided for the removal of snags and rocks from the channel and for bank protection. The total cost of work under this authorization was $3,768,000. The channel work has prevented damages to the limited river transportation activities in this reach of the river, and the bank protection works have prevented loss of land through bank erosion. Emergency Bank Protection Middle Missouri River Basin Completed Projects, Local Protection (Omaha District) Section 14 of the Flood Control Act of 1946, as amended, provides for the construction of emergency streambank and shoreline protection to prevent erosion or flooding from damaging highways, bridge approaches, hospitals, churches, schools, and other non-profit facilities. The Corps works with the project sponsor to define the problem, evaluate solutions, select a plan, develop the design, and construct a project. If a public facility is in imminent danger, a reconnaissance study is conducted and paid for by the federal government. If a feasible solution is found, the Corps and the project sponsor cost-share construction of the project. The local sponsor's share of the construction cost varies from 25 to 50 percent. The federal investment in the solution is limited to a maximum of $500,000 per project. An emergency bank protection project to provide protection to the abutments of Bridge VA-21 on Pottawattamie County Road G-30 over the West Nishnabotna River, four miles west of the town of Hancock, was completed in September 1977 at a total cost of $77,300 ($66,600 was the federal cost). In June 1980, an emergency bank protection project to provide protection to the left abutment of a bridge on Pottawattamie County Road G-66 over the East Nishnabotna River, four miles west of the town of Griswold, was completed at a total cost of $12,300. An emergency bank protection project was completed in September 1983 at a total federal cost of $182,000 to provide protection for Crawford County along the East Fork of the Boyer River just south of the city of Vail. Bank stabilization along the East Fork of the Boyer River, which is adjacent to the city's sewage lagoons, is provided by the project. The project prevents erosion and bank sloughing from encroaching into the sewage lagoon containment embankment. An emergency bank protection project along the left bank of the Big Sioux River in Plymouth County now protects a portion of State Highway 12 located approximately 1-1/2 miles north and 1-1/4 miles east of Jefferson, S.D. The project, completed in March 1986 at a cost of $70,700, consists of 450 feet of revetment and 15 feet of windrow refusal. A second project along the left bank of the Big Sioux River in Plymouth County near Jefferson, S.D., was completed in October 1986 at a cost of $71,600. This project, which also protects a portion of State Highway 12, consists of 200 feet of revetment and 20 feet of refusal. An emergency bank protection project along the right bank of the Little Sioux River was constructed about three miles south of Anthon in May 1987. This project, consisting of 300 feet of revetment and 15 feet of windrow refusal, protects a portion of State Highway 31. The federal cost of the project was $43,000. An emergency bank protection project along Muckey Creek near Mapleton, Iowa, was constructed in October 1988 under Section 14 authority to protect State Highway 141. The project consisted of a 120-foot stonefill revetment with a 15- foot windrow refusal and three rock drains and was completed at a total project cost of $26,900. An emergency bank protection project along Waterman Creek near Sutherland in O'Brien County, Iowa, was constructed in January 1989 under Section 14 authority to protect a county road. The project consisted of a 140-foot stonefill revetment with a 40-foot windrow refusal and was completed at a total project cost of $47,600. An emergency bank protection project along the Soldier River near Ute in Monona County, Iowa, was constructed in April 1989 under Section 14 authority to protect State Highway 183. The project consisted of a 200-foot stonefill revetment with a 30-foot windrow refusal and was completed at a total project cost of $41,600. An emergency bank protection project along Keg Creek near Minden in Pottawattamie County, Iowa, was constructed in May 1989 under Section 14 authority to protect Minden's sewage lagoons. The project consisted of a 300-foot stonefill revetment with a 40-foot refusal and was completed at a total project cost of $77,200. An emergency bank protection project along the left bank of the West Nishnabotna River near Oakland, Iowa, was constructed in August 1990 under Section 14 authority to protect Pottawattamie County Bridge G-42. The project consisted of 150 feet of stonefill revetment and 40 feet of windrow refusal and was completed at a total project cost of $37,500. An emergency bank protection project along the West Nishnabotna River near Malvern, Iowa, was constructed in August 1990 under Section 14 authority to protect County Road L-68. The project consisted of 455 feet of stonefill and windrow revetment with a 50-foot windrow refusal and was completed at a total project cost of $65,400. In January 1993, an emergency bank protection project to protect Page county Road J-14 and a bridge over the East Nishnabotna River, about seven miles southwest of the town of Red Oak, was completed at a total project cost of $83,000. Flood Plain Management Services Program Middle Missouri River Basin (Omaha District) The Flood Plain Management Services Program has provided for numerous services over the years to public and private entities in an effort to achieve flood damage reduction. This effort has been in the form of published studies such as the flood plain information reports listed in the back of this booklet and numerous unpublished studies and technical assistance. The Water Resources Development Act of 1990 requires that all services to federal agencies and private entities be on a 100-percent reimbursable basis. Services to non-federal public entities are provided free of charge.