Producing River Profiles and Topographic Maps for Sampling Rivers

Bob Waltermire, Terence P. Boyle, and Ann D. Richmond, Midcontinent Ecological Science Center

Three rivers in the Pictured Rocks National Lakeshore, Michigan, were sampled for physical geomorphic characteristics and macro invertebrates as part of a land use/aquatic resources risk analysis. The sampling scheme was hierarchical and at the largest spatial extent was directed at the geomorphology of the river valleys. However, physical access to the rivers was extremely difficult and hampered sample site selection by the field technicians and the project director. GIS products, including river profile plots, profile tables, and a topographic map displaying rivers, elevation contours, and a 100 cm UTM grid, were used to plan sampling schemes by stratifying the rivers into "valley sections", and to maximize sampling efficiency. Field technicians in Michigan, and their supervisor stationed in Colorado, had identical GIS-generated field reference materials which enabled them to effectively communicate throughout the field season. Initially, river profiles were generated from USGS DEMs and river arcs from the Michigan Resource Information System data base, but the results lacked sufficient accuracy. A second approach was to produce river profiles using river arcs generated from the DEMs, but the results were also inadequate. The successful procedure required digitizing contours in a 400-meter buffer area around each river, building a grid using the TOPOGRID utility, and using SURFACEPROFILE to generate river profiles based on river arcs digitized from the same USGS 7.5-minute quadrangles. The results were usable river profiles, profile tables, and topographic maps which were generated from the digitized data. This paper will emphasize the ArcInfo tools and procedures required to create topographic surfaces and river profiles from digitized contour data.

Description of Basinsoft, A Computer Program to Quantify Drainage-Basin Characteristics

Craig Harvey and David Eash, U.S. Geological Survey, Water Resources Division

A computer program named Basinsoft has been developed to use geographic information system (GIS) software to quantify 27 selected morphometric characteristics for a drainage basin using digital cartographic data. The characteristics quantified include the basin measurements of area, length, slope, relief, shape, and aspect, and the channel (stream) measurements of length, slope, sinuosity, density, order, and frequency. Basinsoft was originally developed in 1988 to use digitized topographic-map data to quantify 16 selected morphometric characteristics. Since the original coding of Basinsoft in 1988, the programs comprising Basinsoft have been further developed and extensively upgraded. They have been converted from PRIME(1) to Data General UNIX operating systems, tested to verify the accuracy of quantifications, and documented. The programs now comprising Basinsoft are written entirely using ARC Macro Language (AML) to ensure portability between computer platforms running ArcInfo revisions 7.0 or greater. Basinsoft requires the generation of four source-data layers representing the drainage divide, hydrography, hypsography, and an elevation model of a drainage basin; and the assignment of attributes to three of the four source-data layers. Generation of and assignment of attributes to these data layers is facilitated by utility programs developed specifically for these purposes. An optional program included with Basinsoft can be used to quantify area-weighted characteristics for a drainage basin. Area-weighted characteristics can be quantified from a variety of potential data sources that represent the distribution of characteristics such as precipitation, land use, soils, and geology. Comparison tests between Basinsoft quantifications and manual topographic-map measurements of 12 primary basin characteristics support the validity of Basinsoft computations. Results indicate that Basinsoft quantifications of basin slope are dependent on source data used to generate the hypsography source-data layer. Because of inherent differences between the data sources, basin slope is accurately quantified when digitized topographic-map data are used to generate the hypsography source-data layer and significantly underestimated when digital-elevation-model data are used. Compared to manual methods of measurement, Basinsoft significantly decreases the amount of time and effort required to quantify selected basin characteristics. The simplicity and automation of Basinsoft, and accompanying utility and optional programs, facilitates application of Basinsoft without requiring extensive GIS experience. Basinsoft has been used by the U.S. Geological Survey (USGS) to quantify characteristics for 164 drainage basins in Iowa for the development of statewide flood-estimation equations and for more than 500 watersheds in the Columbia River Basin, in the northwestern United States, for analyses used in the interagency (U.S. Forest Service and U.S. Environmental Protection Agency) Eastside Ecosystem Management Project. Basinsoft is currently being used by the USGS to quantify characteristics for drainage basins in Nebraska for the development of statewide flood-estimation equations. The USGS National Water-Quality Assessment Program (NAWQA) National Synthesis Team is investigating the use of Basinsoft to provide consistent basin-characteristic quantifications for the Nation's NAWQA study units. In addition to multiple-basin processing for regional studies, Basinsoft can also be used to process single basins to quantify input characteristics for hydrologic modeling. (1)The use of trade, product, industry, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Investigating Stream Channel Morphology Using a Geographic information system

Scott N. Miller, U.S. Department of Agriculture; Phillip D. Guertin, University of Arizona; David C. Goodrich, U.S. Department of Agriculture

This paper will present the results of a study that utilized GIS to investigate watershed and channel morphmetric relationships on the Walnut Gulch Experimental Watershed near Tombstone, Arizona. The goal of the study was to derive predictive relationships of stream channel characteristics using a high-resolution ArcInfo GIS database. Two hundred twenty-two channel cross-sections were surveyed in the Walnut Gulch Experimental Watershed. ArcInfo AML programs were created to analyze each of the 222 subwatersheds contributing runoff to the sample locations. These subwatersheds were characterized based on information extracted from the GIS, including such variables as watershed area, stream order, flow length, and slope. Regression analysis was used to develop relationships between channel characteristics (average depth, width and area) and watershed variables, yielding highly significant relationships. These results indicate that the procedures used in this study could greatly improve our understanding of geomorphological processes, as well as provide tools to assist in the rapid and accurate parameterization of hydrological models.

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