- 1. Study unit: Use the code (table 1) designated for each study
unit.
- 2. Date: Record the date as month, day, year.
- 3. Station name: List the USGS station name or create a station
name for the site.
- 4. Station identification number: List the USGS station
identification number for the site.
- 5. Investigators: Self explanatory.
- 6. Reference location: Briefly describe reference location.
The reference location should be a permanent structure such as a USGS gage
or a bridge. When a permanent structure is not present, a semipermanent
marker (such as an iron pipe) is installed at a site. The
reference location serves as a classification variable, providing a
geographic marker linking habitat data collected at the basin level with
data collected at subsequent levels of the spatial hierarchy. Record the
latitude and longitude of the reference location.
- 7. Drainage area: Delineate drainage basin boundaries on a
1:24,000-scale 7.5-minute quadrangle map (7.5' map) and calculate the
drainage area of the basin upstream of the reference location. For items
7 through 13, if the information cannot be obtained realistically from 7.5'
maps, then collect the data at 1:250,000-scale resolution.
- 8. Drainage density: Measure the cumulative length of all
perennial streams and canals in the basin upstream of the reference location,
as noted on a 7.5' map. Then divide the cumulative length by the drainage
area to calculate drainage density.
- 9. Drainage texture: Drainage texture is an expression of the
closeness of spacing of stream channels in the basin upstream of the
reference location and is calculated by determining the basin contour with
the most crenations, as noted by visual inspection of a 7.5' map. Following
that contour, determine the number of channel crossings. Divide the number
of stream channel crossings by the length of the perimeter of the basin.
- 10. Drainage shape: To determine drainage shape, measure
the basin length, square it, and divide it by the drainage area, using a
7.5' map.
- 11. Stream length: Measure the length of the stream from the
headwaters to the reference location, as noted on a 7.5' map.
- 12. Basin relief: Determine the highest elevation in the basin
minus the elevation of the reference location as noted on a 7.5' map.
- 13. Storage: Determine the cumulative area of the drainage that is
composed of stored water, including reservoirs, lakes, ponds, swamps, and
wetlands, using a 7.5' map.
- 14. Ecoregion: Record up to three of the spatially dominant
ecoregions for the basin upstream of the reference location and the
percentage of the basin that each occupies. Omernik (1987) identified
relatively homogeneous ecological regions of the United States based on
regional patterns of spatially variable combinations of land use, mineral
availability (soils and geology), potential natural vegetation, and
physiography. Ecoregions have been compiled at two map scales, a national
map at 1:7,500,000-scale resolution and regional maps at 1:2,500,000-scale
resolution. State maps may also be available. The national coverage scale
(1:7,500,000) is provided; record the local coverage scale of the highest
resolution available.
- 15. Physiographic province: Coverage of a national map of
physiographic provinces is available as a GIS data base and is derived from
25 physiographic provinces representing distinct areas that have common
topography, rock types and structure, and geologic and geomorphic history.
Record up to three of the spatially dominant physiographic provinces for the
basin, upstream of the reference location, and the