Water: WARSSS
Science & TechnologyApplications & DatabasesTechnical ToolsWARSSSUSGS Regional CurvesUSGS Regional Curves
Prediction Level
Assessment
Steps
Hydrologic Relations1. USGS Regional Curves
2. Drainage Arearat
3. Field Calibration
4. Final Determination
Stream Morphology
5. Stream Classification
6. Dimensionless Ratios
Stability Analysis
7. Channel Stability
8. Bank Erosion Prediction
9. Bank Erosion Rates
Flow/Sediment Relations
Sediment Rating Curves
10. Flow Modifications
11. Dimensionless Flow
12. Bankfull Q & Sediment
13. Dimensionless SRCs
14. Bedload Rating
15. Flow Duration Curves
16. Flow-Related Yield
17. Flow-Related Increases
Supply Changes
18. Channel Changes
19. Bedload Transport
20. Hillslope Processes
21. Hillslope Sediment
22. Entrainment Calculation
Stability Consequences
23. Sed. Transport Changes
24. Aggradation Potential
25. Degradation
26. Enlargement
Summary Analysis
27. State Shift
28. Total Sediment
29. Departure Analysis
30. ID Loads by Category
Bankfull channel dimensions of cross-sectional area, width, mean depth, and the related streamflow velocities tend to increase linearly with increases in drainage area (Leopold et al. 1964). When stratified by stream type, plots of bankfull channel dimensions prove even more useful for estimating similar channel dimensions for ungaged areas.
For example, selected average bankfull channel dimensions for four hydro-physiographic regions are shown in Figure 99 (PDF, 157 kb, 1 p.) (Dunne and Leopold, 1978).
The majority of these streams are alluvial channels. The bankfull channel dimensions that have been collected and field-calibrated at stream gages should be plotted similarly in order to build a supporting database useful for refining estimates of bankfull channel dimensions for ungaged areas. 
As one constructs local relationships and curves from the gage data, the plot of bankfull channel dimensions by drainage area should not only be integrated or stratified for a hydro-physiographic province, but also by stream type. Follow the progression in Figure 100 (PDF, 45 kb, 1 p.) for development of regional curves (Leopold,et al, 2000).
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