A General Perspective of Discharge-Area Relationship during Recession

One of the compelling problems in hydrology is to predict discharge at a point in a river network without any historical data. Any solution to such a problem requires knowledge of how a drainage basin functions, thus linking its response to precipitation inputs with its physiological characteristics. In this regard, considerable efforts have been made to understand the link between basin size and peak discharge. The present study extends the discharge-area analysis to the recession domain. We assumed two dominant flow processes to exist in natural basins viz; Pure Surface Flow (PSF) and Mixed Surface Sub-surface Flow (MSSF). As the recession progresses, MSSF is expected to become the dominant flow generation mechanism in the basin. The MSSF is directly proportional to the total length of the saturated channel network or active drainage network (ADN) in a basin, which is directly proportional to the basin area. Thus, during the late recession period, the discharge is supposed to be directly proportional to the basin area. Using a geomorphological hydrologic response model, we tried to prove this direct relationship between discharge and basin area during the recession period. The results obtained are in agreement with our assumed hypothesis.