GEM 4409
Hydrology
Fall 2005
TROY
UNIVERSITY
Hydrologic Cycle
Estimating Runoff
1. Drainage Basin Characteristics
• Size
• Shape
• Slope
• Land Use
• Geology
• Soil Type
• Storage Capability
2. Stream Channel Characteristics
3. Flood Plain Characteristics
4. Weather Characteristics
• Precipitation Type
• Precipitation Amount
• Storm Size
• Storm Direction
• Storm Intensity
Selection of Methodology
1. Small Drainage Basins
• Rational Method (Q = CIA)
2. Midsize Drainage Basins
• USGS Regression Equations
• SCS Curve Number Methods
• Hydrographs
• TR-55 Method
3. Large Drainage Basins