This document discusses hydrograph analysis and the components of a hydrograph. A hydrograph is a graph that shows the rate of water flow over time at a specific point within a river or channel. It examines the factors that influence a hydrograph, including surface runoff, subsurface runoff, and groundwater runoff. Time parameters like time of concentration, lag time, time to peak, and recession time are also important inputs for hydrograph analysis. The document also outlines three common methods - the straight line method, two lines method, and curves extension method - for separating base flow from direct runoff within a single peaked storm hydrograph.