Approach

The DEC approach to monitoring developed over a period of time in cooperation with previous work with the Vicksburg District of the U.S. Army Corp of Engineers (WET, 1989), WES, SCS, ARS, and other investigations.

The approach recognizes that the watershed problems of the 21 sites being analyzed in the Yazoo Basin of Mississippi must be placed in the context of the entire watershed of the area. Identification of the watershed problems can be done in a number of ways. Interviews with local government officials, local landowners and field reconnaissance generally will pinpoint the major problems in a watershed. Most of the watersheds will have all or some of the following types of problems:

• Watershed erosion
• Channel erosion
• Agricultural and urban flooding
• Sedimentation of reservoirs and agricultural land
• Damage to infrastructure (bridges, pipelines, etc.)
• Environmental problems

Data Sources

In previous investigations of Yazoo Basin watersheds, the following agencies have been sources of historical information:

• U.S. Army Corps of Engineers -Vicksburg District, Waterways Experiment Station, & Lower Mississippi Valley Division
• U.S. Department of Agriculture, U.S. Soil Conservation Service, and U.S. Agricultural Research Service
• U.S. Geological Survey
• State Highway Department, Archives, Geological Survey, and Land Office
• County Offices
• City & Municipality Offices
• State & Local Historical Societies
• Newspapers
• Local Drainage and Levee Districts

Types of information obtained from these sources are:

• Channel and reservoir surveys
• Flood history
• Watershed workplans
• Bridge plans & subsequent surveys
• Watershed erosion information
• Geological data
• Drainage District records
• Land use records
• Previously installed erosion mitigation measures
• Land ownership information
• Historical sediment yield data
• General Land Office Survey plats and aerial photographic coverage

Field Investigation

A field investigation attempts to place the channel reach of interest in a watershed context. Aerial reconnaissance, or at least a drive to accessible points within the watershed prior to ground level investigation, provides a much broader view of the watershed problems. One of the primary purposes of the project is to monitor the performance of grade control and bank stabilization constructed in the streams. Observations to be recorded include photographs, movement of riprap since construction, exposed filter material, erosion upstream and downstream of structures, planform geometry of the stream, geology information, and sediment samples.