Modeling Concepts
- The Rational Method is a simple runoff model that takes into account land use characteristics for small basins using a land-use runoff coefficient, or "C" value.
- C values vary from near zero in rural or forested areas to almost 1.0 in urban areas and parking lots.
- Lumped models are relatively simple in that the basin is treated as a single unit
- Basin-averaged hydrologic and meteorological inputs are used
- A semi-distributed or pseudo-distributed model breaks the basin down into a collection of smaller sub-basins than the lumped-model approach
- Distributed models represent details of the hydrologic and meteorological characteristics by representing basins with a grid.
- The distributed modeling approach is:
- Much better at representing variability in hydrologic response within the basin
- More realistic for flash flood modeling
- More computationally intensive than lumped modeling
