What Is Direct Runoff Hydrograph?

Direct runoff hydrograph resulting from a unit depth of excess rainfall occurring uniformly on a watershed at a constant rate for a specified duration. Unit pulse response function of a linear hydrologic system. Can be used to derive runoff from any excess rainfall on the watershed.

What is direct runoff?

Direct surface runoff is the rain or meltwater that runs off during the rain or melt event as overland flow or in the vegetation cover above a frozen soil. The meltwater and the rain falling onto snow or on frozen ground reach a stream along different pathways.

How do you get a direct runoff hydrograph?

A direct runoff hydrograph can be obtained by using the discrete form of convolution integral as shown below. Where Q is the runoff ordinate, P is the rainfall pulse and U is the unit hydrograph ordinate.