Michigan tribal lands and areas of interest vulnerable to oil spills

In order to better protect unique commercial, environmental, and cultural resources from oil spills, the Oil Pollution Act of 1990 mandated a coordinated effort by federal, state, and local regulatory agencies and the regulated community to enhance oil spill preparedness and response. This coverage provides the location and attached data for the mapping area. The development of spatial databases and geographic information systems is done pursuant to implementing the preparedness and response mandates of the Oil Pollution Act of 1990. These data were prepared at map scales of 1:24,000 and 1:100,000 and are best used in applications of comparable resolution. In addition, these data were developed to meet specific project objectives and therefore may not represent exhaustive feature inventories. Locational information and the attached database information for the tribal interest coverage were primarily obtained from the members of tribal administrations and local government agencies after an initial identification period that included the use of generic maps and information from U.S. federal, state, regional, and local agencies with holdings in the Michigan Mapping Area were also contacted for site-specific information. The 7.5 minute quadrangle maps, as digital raster graphics, were also used as a base layer for locational and boundary information. The Delorme Atlas and Gazetteer series for Michigan also provided additional supporting information for location and in some instances basic contact information. Phone and mail correspondence was also used to fill in applicable data gaps in preparation of the draft atlas. The data was plotted in a GIS using ESRI's ArcView 3.2 and displayed against the digital raster imagery at a scale of 1:24,000. Data links were incoporated into these GIS files to match the mapped sites to the appropriate data record as outlined in Section 5.2.1, Entity and Attribute Overview. Draft hard copy atlases were prepared from this data, supplied by the Great Lakes Commission, and the USGS's Upper Midwest Environmental Sciences Center (UMESC) in Onalaska, Wisconsin. The UMESC produced hard copy maps in portable document files (.pdf) format at scales of 1:25,000 and 1:100,000. These maps were then reproduced and distributed by the Great Lakes Commission for external review by primary source data holders. All updated, corrected and amended information was then added to the project files and returned to the UMESC for distribution in .pdf hardcopy format; and electronic distribution via CD-ROM and the Internet. Final electronic formats include ArcView 3.2 shapefiles, .e00 ArcExport files, .pdfs, and converted CAMEO/Landview files. Regional data was merged using Geoprocessing Wizard to create a statewide coverage and was then clipped to the Huron Basin, which included a 25 kilometer buffer. The Huron basin coverage was reprojected, changing the datum from NAD 27 to NAD 83, using the MI DNR Projection Extension. Great Lakes Commission staff working on the Area Contingency Planning project verified all descriptive and spatial attributes and collected confirmation from owners and/or managers of attributes and boundaries via surveys or direct external review. Spatial data were cross-checked with multiple sources. Data were developed for this layer utilizing multiple primary sources, from federal, state, and local governmental agencies and owner/operators of the tribal interests. These primary sources include USGS 7.5 minute quadrangle maps; federal state, local and private land manager/owner hard copy and electronic sources; and an exhaustive holders of data. Initial data were supplied by state agencies maintining tribal lands records state-wide in hard copy and electronic format. Data was reviewed for location and accuracy at the scale of 1:24,000 on appropriate base maps. Location and attribute information is only as accurate and complete as the informaiton specifically applies to each individual record at the time of data development. Data for these facilities are primarily atrributed polygons, plotted in ArcView 3.2 GIS. These polygons were generated in 1999 and updated in 2000 based on current information from primary sources but do not necessarily always exactly overlay the base map 7.5 minute quadrangle maps with previous publication dates. This coverage does not necessarily include all tribal interest areas within the Huron Basin. Exhaustive efforts were made to compile as thorough an atlas as possible, with particular in depth detail paid to those areas in proximity to surface waters. However, under-reporting may occur. Horizontal positional accuracy is tested by visual comparison of hard copy check plots to the source materials and verifying the location of the data on screen relative to other data layers in the same geographic area.