Basin Properties
- With uniform basin characteristics and coverage of rainfall or snowmelt, larger basins result in a larger volume of runoff.
- Uniform coverage is unusual, so runoff is determined by the part of the basin that receives the rainfall; this is known as the contributing area.
- For basins of equal area but different shapes, a long narrow basin will result in a hydrograph that has a lower peak flow and is spread out over a longer time when compared with a "rounder" basin.
- When compared to a meandering stream, a straight stream will result in a stream response that is faster and has a higher peak flow.
- When compared to a relatively flat basin, a steeply sloped basin will result in a stream response that is faster and has a higher peak flow.
- When compared to a stream channel with rough surfaces (lots of rocks and vegetation), a smooth stream channel will result in a stream response that is faster and has a higher peak flow.
- Stream density is the length of all the channels in a basin divided by the basin area.
- High stream density indicates a basin with numerous tributaries and faster, more efficient runoff.
- Urbanization results in increases in both the amount and the speed of runoff.
