Browsing by Author "Bonde, John"
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Item Erosion Hazard of Minnesota's Lake Superior Shoreline(University of Minnesota. Minnesota Sea Grant, 1990) Johnston, Carol; Sales, James; Bonde, John; Aunan, Tim; Raby, RichardThe rugged beauty of bedrock cliffs rising from the waters of Lake Superior creates a memorable impression of Minnesota's Lake Superior coast. But unlike the resistant bedrock that creates beautiful vistas, some sections of the Minnesota shoreline are erosive sand or clay banks. Buildings and roads built in these areas are threatened by the gradual wearing away of the coast by the powerful waves of Lake Superior. While shoreline erosion can only be prevented at great expense, economic losses are minimized by knowing where and how fast shoreline erosion is likely to occur. Future problems are avoided by locating new structures and septic fields back from the bluff line to allow for the erosion that is expected to occur. Fortunately, the Minnesota Lake Superior shoreline has had relatively little development in comparison to other Great Lakes shorelines, so good planning can prevent future problems. There are several ways to identify erosion hazard areas. On-site monitoring of erosion is the most precise way to measure short-term erosion rates, but can be misleading as an indicator of long-term hazard if unusual conditions during the monitoring period cause uncharacteristically high or low erosion rates. Measuring shoreline recession from a time sequence of maps or aerial photos provides longer-term erosion rates. Shoreline geology also provides an indication of erosion hazard, because some types of geologic materials are more resistant to erosion than others. This study combined the latter two methods to produce maps of long-term shoreline erosion potential.Item Erosion Study Aerial Photographs and Documentation(1990) Johnston, Carol; Sales, James; Bonde, John; Aunan, Tim; Raby, RichardAerial photographs and documentation related to: Johnston, Carol; Sales, James; Bonde, John; Aunan, Tim; Raby, Richard. (1990). Erosion Hazard of Minnesota's Lake Superior Shoreline. University of Minnesota. Minnesota Sea Grant. Retrieved from the University of Minnesota Digital Conservancy, https://hdl.handle.net/11299/189149.Item A Georeferenced Aerial Video Imaging System Annual Report(University of Minnesota Duluth, 1994) Johnston, Carol A; Bonde, JohnThe objective of this project is to develop a system to georeference airborne video Imagery using Global Positioning System (GPS) technology. The system will make it possible for video images taken from an airplane to be used to make maps that could be interfaced with other data layers in a Geographic Information System (GIS). The uniqueness of the proposed system is its real-time georeferencing capability, which greatly accelerates the conversion of video images into a mosaiced, georeferenced digital database.Item Land Use and Water Resources in the Minnesota North Shore Drainage Basin(University of Minnesota Duluth, 1991) Johnston, Carol A; Bonde, John; Meysembourg, Paul; Allen, Brian; Sales, JamesThe major land use change currently occurring in the Lake Superior drainage basin is the increase in deforestation resulting from demand for wood and paper products, which is projected to increase total harvest by 50% between 1988 and 1995 (Minnesota DNR 1989). We know that the extensive pre-settlement logging of the Great Lakes drainage basin affected water quality, as indicated by sediment evidence of increased phosphorus concentrations (Kemp et al. 1972) and diatom production (Stoermer et al. 1985; Schelske et al. 1988), and model predictions of increased phosphorus loading (Chapra 1977). However, we don’t know the magnitude of land affected by more recent clearcutting, nor its effects on water resources. The purpose of this report is to describe these land use changes and other characteristics of the Minnesota North Shore drainage basin that could potentially affect fluxes of sediment and nutrients into Lake Superior.Item Mapping Lake Trout Spawning Habitat Along Minnesota's North Shore(University of Minnesota Duluth, 1999) Richards, Carl; Bonde, John; Schreiner, Don; Selgeby, James; Cholwek, Gary; Yin, K. KarenLake Superior's surface covers more area than any other body of fresh water in the world. While it is the largest of the Great Lakes, less is known about it than any of the other lakes in the chain. Lake Superior supports a variety of life and its nearshore area is vital to its overall ecosystem as well as to many fish species that inhabit the lake. Lake trout (Salvelinus namaycush) have historically been the top predator in the Lake Superior fish community and are the primary species caught by anglers. Lake trout are well adapted to the cold, clear, infertile waters of Lake Superior and generally require boulder and cobble substrates at depths less than 30 meters for spawning and early survival of eggs and fry (Marsden et al., 1995). An important component of lake trout management in Lake Superior has been the protection of known spawning areas. Stocking suitable habitat with hatchery reared lake trout is a management strategy based on the belief that adult fish returning to these areas will have increased early survival of eggs and fry. Biologists also believe that early life stages of lake trout stocked on appropriate spawning substrates will imprint and re-colonize these spawning areas more quickly than if left to normal population expansion (Krueger et al., 1986). These approaches require site specific knowledge of the distribution and areal extent of bathymetric features and substrate type so that efforts can be concentrated in specific areas where success is likely. An important information need, discussed in the Fisheries Management Plan for the Minnesota Water of Lake Superior (MNDNR 1995), is the identification and quantification of lake trout spawning habitats. Unfortunately, detailed maps of Lake Superior's benthic habitats sufficient for identifying potential lake trout spawning habitats are largely nonexistent in Minnesota waters. With the exception of embayments and ports extensively used for shipping, contemporary bathymetric maps of the lake are built from data consisting of a few depth measurements per square kilometer. While these maps are sufficient for describing the general shape of the lake 's bottom for general navigation purposes, they are insufficient to depict detailed fish habitat. Furthermore, the substrate of the lake is largely unknown. When looking out over any large body of water, it is difficult to tell what might lie underneath. The shoreline geology can provide a clue, but what is on shore is not always the same as what lies a few hundred meters, or even just a few meters, offshore. Very few systematic surveys of substrate type have been conducted and no maps exist. To date, the long length of the shoreline and cost associated with conducting such surveys have prohibited extensive surveys. Even mapping just a square kilometer of near shore area with traditional methods would have been a major undertaking.Item Natural Resources of Minnesota Point: Maps and Data in Support of the Minnesota Point Environmental Plan(University of Minnesota Duluth, 1999) Johnston, Carol A; Trauger, Amy; Meysembourg, Paul; Bonde, John; Hawrot, Rita Y; Walton, Gary BIncludes maps and data regarding ecological subsections of Minnesota, information regarding the distribution and relationships of habitats and birds in the St. Louis River estuary, a map and inventory of open space in Duluth, and a map and data from an aquatic habitat survey (fish monitoring) in the Park Point area.