Browsing by Author "Sales, James"

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    Erosion Hazard of Minnesota's Lake Superior Shoreline
    (University of Minnesota. Minnesota Sea Grant, 1990) Johnston, Carol; Sales, James; Bonde, John; Aunan, Tim; Raby, Richard
    The 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.
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    Erosion Study Aerial Photographs and Documentation
    (1990) Johnston, Carol; Sales, James; Bonde, John; Aunan, Tim; Raby, Richard
    Aerial 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.
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    GIS and Modeling in Ecological Studies: Analysis of Beaver Pond Impacts on Runoff and its Quality
    (University of Minnesota Duluth, 1994-02) Nawrocki, Tatiana; Johnston, Carol A; Sales, James
    The ARC/INFO GRID module was used to derive watershed variables for input to AGNPS, a cell-based runoff model that estimates water volume, peak flow, eroded and delivered sediment, chemical oxygen demand, and nutrient export from watersheds (Young et al. 1987). The boundary of a 534 ha watershed in Voyageurs National Park was hand-digitized from 1:24,000 topographic maps, and used to clip elevation data from a 7~ minute U.S.G.S. Digital Elevation Model (DEM) with 30 m mesh-point spacing. ARC/INFO GRID was used to generate slope, slope shape, and field slope length for each of the 90x90 m cells used to subdivide the watershed. A surface runoff network was then generated using the FLOWDIRECTION, FLOWACCUMULATION, and STREAMLINE hydrologic modeling tools in ARC/INFO GRID. Each of the 90x90 m cells was uniquely numbered, and receiving cell numbers were derived for each source cell based on FLOWDIRECTION results. A 1:24,000 land cover map (Allen et al. 1993) was digitized and gridded to derive Manning's roughness coefficient, surface condition constant, and chemical oxygen demand factor for each cell. Detailed soil maps have never been made for the wilderness study site used, so land cover classes were coupled with information about soil series from nearby mapped sites to estimate soil texture, soil erodibility factor, and hydrologic group (to derive SCS curve numbers). The drainage area for each beaver impoundment in the watershed was derived from a digital database of subwatersheds. All variables were exported from ARC/INFO into the Microsoft Excel spreadsheet program, which was used to generate a data file in the appropriate format for AGNPS. The methodology was applied to the 534 ha, third order stream watershed to determine the influence of beaver ponds on water quality and quantity. Beavers influence runoff by: 1) constructing dams that retard the flow of water, 2) creating ponds that promote sediment deposition and increase phosphorus retention, and 3) changing forest land cover to water and wetland vegetation. We ran the model for a range of storms with average 24-hour rainfalls equivalent to a 1 yr, 2 yr, 5 yr, 10 yr, 25 yr, 50 yr, and 100 yr storm, based on National Weather Service records for the region. Model runs for the beaver-impounded landscape ("with ponds") were compared with those for the same watershed without the influence of beaver ("no ponds"), based on historical vegetation and adjacent forest types. The ''with ponds" scenario resulted in slightly increased water flow at the mouth of the watershed. This is because, assuming that the pond is full, 100% of the rain that falls onto it will flow off of it. This caused a 10% increase in runoff at the lowest rainfall intensity, but only a 1% difference during the 100 yr storm. The runoff contribution of individual cells changed relatively little between the two scenarios, but there were easily discernable differences in accumulated runoff per cell ii: with distance downstream. Sediment deposition in the beaver ponds also had an effect that accumulated downstream, so that the ''with ponds" scenario yielded 7 to 12% less sediment than the ''no ponds" scenario, an effect that increased with storm intensity. The model predicted a 4% decrease in watershed nitrogen output with ponds for a 1 yr storm, but there was no effect for storms with a 10 to 50 yr frequency, and a net increase for a 100 yr storm. This implies that while beaver ponds may retain N during low-intensity storms, there may be a flushing of that retained N during high-intensity storms. This pattern is visible on GIS maps for "with ponds" scenario with low intensity storm: higher nitrogen concentrations were observed at the locations, where no ponds were situated, and nitrogen content in runoff had remarkable alterations in cells adjacent to ponds. Chemical oxygen demand (COD) showed the largest effect of any of the parameters predicted: the presence of beaver ponds was associated with a 10 to 17% reduction of COD, depending on the storm intensity. This is because a forest has a lot more primary productivity than a pond, and therefore contributes more organic matter (and therefore COD) to the system. This model-based approach provided insight into the landscape scale influence of beaver ponds that could not have been derived using conventional field techniques. The modeling was done at a spatial level of detail that would have been impractical using manual data entry to AGNPS. Automating the derivation and interchange of variables with a GIS made this research possible.
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    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, James
    The 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.
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    Minnesota's Forest Bird Diversity Initiative FY02-03 Final Report
    (University of Minnesota Duluth, 2003) Niemi, Gerald J; Hanowski, JoAnn M; Danz, Nicholas P; Lind, Jim; Jones, Malcolm T; Sales, James
    The Minnesota Forest Bird Diversity Initiative (MFBDI) was initiated in 1991 as a comprehensive monitoring, research, and education effort to maintain Minnesota’s rich diversity of forest birds. The Initiative was motivated by: 1) forest-related problems in the eastern US and emerging issues in the Pacific Northwest US, 2) a major study on the potential effects of increased forest harvesting and management in Minnesota (known as the GEIS) indicated that forest birds may exhibit substantial changes in the future unless several mitigation measures were implemented, and 3) little was known about many fundamental issues on the ecology of forest birds. These included limited information on a) population trends of forest birds, b) factors associated with nest success, c) how landscape level changes affect forest bird distribution and abundance, d) how forest management activities affected forest birds, and e) the ability to predict the effects of increased forest harvesting (three-fold increase from 1950 to 1990) on forest birds. Significant progress has been made during this 12-year effort towards improving our understanding of Minnesota’s forest birds. Major accomplishments include: 1) establishment of a comprehensive and effective monitoring program throughout the forested areas of Minnesota to identify habitats used by birds and to detect trends in populations; 2) examination of recent population trends (using data gathered during the past twelve years from the Initiative’s monitoring program) and long-term population trends (using data gathered during the past 37 years from the US Geological Survey’s Breeding Bird Survey roadside routes) to identify forest birds with declining populations; 3) development of a detailed, state-of-the-art classification of Minnesota’s forested areas using satellite imagery (30 m pixel resolution); 4) development of many species-specific models relating bird distribution and abundance to forest cover, age, and landscape patterns; 5) completion of a variety of nesting studies on forest birds that have revealed low reproductive success in southeastern Minnesota and highly variable reproductive success in northern Minnesota; 6) a simulation analysis of the Nashwauk Uplands for four alternative management scenarios - an analysis that links a landscape, succession, and disturbance (LANDIS) model of forest change with the response by forest birds, 7) a prediction on the potential effects of forest plan alternatives that have been proposed for managing the Chippewa and Superior National Forests, and 8) production of a multitude of materials to transfer the knowledge gained from this effort to landowners, land managers, foresters, wildlife biologists, and others. The latter includes the delivery of more than 130 presentations; over 40 peer-reviewed publications and technical reports; training of ten graduate students and two post-doctoral associates; publication of a book, Birds and forests: a conservation and management guide, that reviews current research and management guidelines on birds and their relationships to forest habitats; organizing and participating in numerous workshops on forest bird management and conservation; and publication of a small booklet, Planning for the birds: things to consider when managing your forest, for distribution to private woodland owners through the Forest Stewardship Program. Most of this information is summarized in a web site on Minnesota’s forest birds - www.nrri.umn.edu/mnbirds.