METHOD FOR DETERMINING RUNOFF

A real-time hydrologic modeling system to determine the hydrologic properties a selected geographic region. In a preferred embodiment, a drainage network of individual cells is created for the geographic region. The outflow of a selected cell within the drainage network is determined by solving the runoff from cells upstream of the selected cells until the flow of all upstream cells is known. The flow value of a cell is based upon factors such as runon, infiltration, and precipitation. In another embodiment the outflow of a selected cell is determined by setting simulated flow rates to equal measured flow rates at observation points upstream of the selected cell and within the drainage network. The flow rates of cells upstream of the observation points are adjusted proportionally based on hydrologic quantities of runoff, precipitation and drainage area to determine the outflow of the selected cell.