Geoscience Reference
In-Depth Information
collars, and mosaicked to cover the entire RWB study area. Subsets were also
provided for wetland basins and counties.
7.3.1.5 National Wetlands Inventory
The National Wetlands Inventory (NWI) data, describing the locations, characteris-
tics and status of wetlands, were downloaded by USGS 7.5
map tiles. These were
mosaicked to form one coverage, then subset to the RWB region, the wetland basins
and associated counties.
7.3.1.6 Land Ownership
Land ownership data were developed for publicly-owned wetland basins.
Ownership boundaries were digitized on-screen from scanned and rectified plat
maps provided by the Nebraska Game and Parks Commission. Plat maps were
scanned at 300 dpi, converted to ERDAS Imagine files and rectified using USGS
1:24,000 digital raster graphics. Digital orthophoto quarter quadrangles (DOQQs)
from 1993 were used to clarify field boundaries, roads and other land features.
Land ownership coverages were considered useful for general planning purposes,
but insufficiently accurate for use in legal or engineering applications.
7.3.1.7 Public Land Survey System and USGS Quadrangle Boundaries
Public Land Survey System (PLSS) township, range and section boundaries
and USGS 1:24,000 topographic quadrangle boundaries were obtained from the
University of Nebraska-Lincoln Conservation and Survey Division. Both PLSS and
quadrangle boundary data were re-projected from Lambert Conformal Conic to
Universal Transverse Mercator zone 14, NAD 83. The data were then subset to the
RWB study area, the wetland basins and associated counties.
7.3.1.8 TIGER Line Files (Roads)
TIGER Line files, obtained from the U.S. Bureau of the Census, were used to repre-
sent the road and highway systems in the study area. TIGER Line data were clipped
to the RWB study area, the wetland basins and associated county boundaries.
7.3.1.9 Digital Soils Data
The USDA Soil Survey Geographic Data Base (SSURGO) files were used as the
primary source of data about the types and characteristics of soils found in the
RWB. RWBJV staff selected the attribute fields required for wetlands management.
Additional miscellaneous water and soil features (e.g., intermittent streams, ponds,
canals, ditches) for wetland basins were digitized on-screen using SSURGO data
as a guide. The SSURGO data were then clipped to the entire Rainwater Basin,
wetland basins and associated county boundaries.
