These interpretive boundaries were designed to alert persons making land use decisions that on-site inspections or further investigations by qualified soils scientists or botanists may be necessary. These interpretive boundaries are necessary because if a proposed activity falls within or near an OFW boundary, different, more stringent permitting review standards are imposed on the permittee's application. This boundary is labeled with the elevation of those contours that are most likely to meet the criteria of supporting obligate and facultative plants and hydric soils. These elevations are 5 or 10 feet apart vertically, so that other information was used to modify the line. However, other indications that the area inside the Special Waters delineation line is likely to meet the rule's criteria are the swamp symbols on the quadrangle, the change in slope that is indicative of the seepage line, or springs that indicate that the groundwater is near the surface at that elevation.
Cultural features can also be helpful.
Similarly, railroads are usually built up high enough to stay dry. This information is generally discernible on USGS 7.5 minute quadrangles. Until we receive full funding to finalize this data, we will coordinate with our field staff to evaluate the boundaries, record needed changes, and make the appropriate adjustments to the boundaries as an on-going programmatic effort. These boundaries are stored in the OFWspec data layer. Tolerances were set to FGDL standards.