AbstractsGeography &GIS

"Simulation of a physical system requires knowledge of all components of the system and their interactions. A probabilistic simulation model of a hydrologic system is developed from short term continuous, sychronized rainfall-runoff records. The individual components of the system area the time between and duration of storms, the depth of rain occurring in each time period of the storm, precipitation excess relations, and the watersheds unit hydrograph. The available data is used to define or develop the probabilistic models involved. The only nonprobabilistic model employed is the watersheds unit hydrograph. It is found that the time between and duration of storms may be represented by an exponential distribution model. In general the depth of rain may be modeled by a log-normal distribution; although a separate model was employed for rainfall extremes. A probabilistic precipitation excess model is developed which relates excess precipitation to total rainfall, season of the year and a random process. The total simulation model yielded synthetic flood frequency curves within the 90% confidence limits of the observed flood frequency curve" – Abstract, page ii.