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The effects of changing levee and water level management practices on present habitat types and amounts on the Upper Mississippi River floodplain at Pool 25 were predicted. The intent of the study was to investigate a broad range of plans that would provide coarse resolution information and the tools needed to study specific plans in the future. Two conditions were investigated for levees: the present levee system and all levees removed. Five water level management plans were studied: the present plan, two plans that would increase water levels, and two plans that would decrease water levels. The levee and water level management variables resulted in a total of ten unique management alternatives. Each was studied...
The likelihood of 1- or 2-foot drawdowns, and the area affected by such alternative drawdowns, was estimated for Pool 13 on the Upper Mississippi River. Minimum water surface (elevation) requirements were compared to computed water surface profiles to determine a critical low flow that would allow a navigation channel 400 feet wide and 10.5 feet deep. An upper limit on flow was established based on the flow at which open river conditions would exist for a given drawdown. The range in flows that would allow for a drawdown was used to estimate success rates using historical daily discharge data. Success rates were determined for a variety of drawdown durations between two time periods, May 1 August 15 and June 15...
An experiment to improve ecological conditions while maintaining a 9-foot (2.74-m) navigation channel was continued in 1995 and 1996 on the three pools of the Upper Mississippi River managed by the St. Louis District, U.S. Army Corps of Engineers. Water levels were held from 1 to 3 feet (0.3 to 0.9 m) lower than maximum regulated elevations at the dam from about mid-June through July in Pools 24 and 25 and Melvin Price Pool. Water levels were then gradually raised as discharge allowed. Vegetation was surveyed along an elevational gradient in eight areas in 1995 and six areas in 1996. Seven plant genera were identified in 1995 and five genera in 1996. Amaranthus spp. (pigweed), Cyperus spp. (chufa), Echinochloa spp....
Analyses of water level elevations and discharge data on the lower Missouri River were made at four stations: Hermann, Missouri, at river mile 97.9; Waverly, Missouri, at river mile 293.5; St. Joseph, Missouri, at river mile 448.2; and Omaha, Nebraska, at river mile 615.9. Data were originally collected by the U.S. Army Corps of Engineers and the U.S. Geological Survey. Analysis was performed at all four stations on data collected between 1928 and early 1994. Trends for minimum, maximum, and mean water levels and discharge are all increasing at the three downriver stations. The same trend was not found at Omaha, but the data used for that station were questionable. The relationship between discharge and elevation...
This report describes an electronic database containing 474 annotated citations that are relevant to fish passage through dams in large temperate floodplain rivers. Our goal was to survey the literature to help define the potential ecological consequences of restricted fish passage through dams in the Upper Mississippi River System and to identify alternative engineering solutions for increasing fish passage in large temperate floodplain rivers. Consequently, topic coverage is broad, including theoretical concepts in large river ecology, engineering design of fish passage structures, ecological responses to river impoundment, fish swimming performance, and relations between freshwater mussels and fish.
The Environmental Management Technical Center is responsible for developing a geographic information system for the Upper Mississippi River System. To assure useful products are developed with a high degree of quality assurance and quality control, the Analysis Team for the Long Term Resource Monitoring Program recommended that standards and conventions for data organization, coding, storage, and transmission be written. This document includes contract specifications for the acquisition of aerial photography, aerial mapping services (contour mapping), digital scanning services, photo interpretation, vector digitizing services, and digital image processing. In addition, file documentation standards are included to...
We estimated the amount of land that would have to be acquired if an alternative water-level management plan was used for Pool 25 on the Upper Mississippi River. The work was performed as part of a study to evaluate water regulation alternatives that could minimize negative impacts and increase ecological benefits of dam operation. We used a one-dimensional model (HEC-2) to estimate the ordinary high-water profile and water surfaces at various discharges and management options, by river mile. Maps of these data were then created with a geographic information system, along with maps of land elevations, both above and below the surface of the river, lands controlled by the managing agency, and levees. The ownership...
This report summarizes monitoring activities of the Long Term Resource Monitoring Program (LTRMP) during 1999 and highlights selected results and accomplishments pertaining to hydrology, water quality, fish, macroinvertebrates, and vegetation. Mean discharge in 1999 was above average in the Upper Mississippi and Illinois Rivers, but spring flooding was relatively minor. Total nitrogen concentration has declined in the upper reaches of the LTRMP study area (Pools 4 and 8) from highs of about 4 mg/L in 1993 to present levels of about 1.5 mg/L. Mass balance budgets indicate that little nitrogen is lost (denitrified) as water moves through the LTRMP study pools on the Mississippi River. La Grange Pool on the Illinois...
Describing the status of the Upper Mississippi River is a continuing function of the Long Term Resource Monitoring Program. Some ecologically important characteristics that serve as indices of overall system status include depositional habitats, vegetation, invertebrates, fish biodiversity, and our capability to apply information to achieve ecological goals. Individual conditions, however, must be regarded as elements of a comprehensive ecological perspective. The filling of depositional aquatic habitats has been measured sufficiently to identify this as the major long term resource problem in navigation pools. However, extrapolating sedimentation rates from one location to another for the purpose of focusing rehabilitation...
Management of water surface elevations at 27 dams affects much of the floodplain habitat in a 653-mi stretch of the Upper Mississippi River (UMR) between St. Louis, Missouri, and Minneapolis, Minnesota. In 1930, Congress authorized most of these dams to maintain a 9-foot navigation channel. This report provides a systemic overview of current operating plans at dams on the UMR and analyzes historical data to determine how well the operating plans are being met. Water level elevations at all 27 dams on the UMR are regulated as a function of discharge, although plans are specific for each dam. The U.S. Army Corps of Engineers strives to maintain a target water level at a specific location in a pool (control point)...
Analysis of water level elevations and discharges was performed for Pool 25 on the Upper Mississippi River as part of a study to increase ecological benefits of the operation of Lock and Dam 25. This dam was placed in operation in May 1939. Since that time, the operating plan for managing water levels has undergone several changes. Discharges for Pool 25 were estimated using data from the closest gaging stations, with corrections accounting for changes in watershed area. Discharge estimates since 1939 were used to compute exceedence frequencies on a weekly, monthly, and yearly basis. They were also used to calculate the percentage of time discharges were within specified ranges for the three time scales. Water level...
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