Inventory and Analysis of Stream Meander Problems in Minnesota

Abstract

Sixteen stream reaches in the state of Minnesota are analyzed for stream shift and meander properties. Aerial photographs and topographic maps are used with a digitizer to produce x-y coordinate data files for valley center lines and stream centerlines. Photographs are chosen for a minimum of two different times, approximately twenty years apart. Data preparation is discussed in Chapter 4. After producing the data files, each stream reach is analyzed for channel shift and meander characteristics using a computer program called MEANDER. The program measures various components of stream shift, the most important of which is the average normal shift. It also measures sinuosity, time rate of change of sinuosity, average curvature, and rate of flood plain area reworking by the stream for the reach in question. A probability distribution curve for normal shift is produced for each stream analyzed. The shift measurement process is described in Chapter 5. Stream reaches are presented beginning on page 2. A ground photo, aerial photos, base map, and digitized map are included for each reach. Hydrologic and geomorphic data are also presented for each reach. The results of the computer analysis are presented as well. The results of the computer analysis for the stream reaches are used in regression analyses to try to determine relations between stream shift properties and stream parameters. Linear and log-linear regression was used in order to develop these relations. The most promising relations produced include average normal shift versus depth, average normal shift versus discharge, rate of area reworking versus depth, and rate of area reworking versus discharge. The discharges and depths in question refer to the two-year flood. The equations should be usable for other streams in the general region. The regressions are presented in Chapter 6.