Baseflow recession characteristic variation with the Basin Morphology.

In the absence of precipitation or any other artificial input source, base-flow, a component of streamflow, sustains natural surface water bodies like rivers and streams. Therefore understanding, identifying, and extracting baseflow from streamflow measurement is essential for many hydrological studies, e.g., estimating watershed characteristics, long-term groundwater storage trends, flow regulations or water policy, water quantity, quality, supply, habitat and informing management of regional water resources. We aim to understand the morphologic factors that are known to influence groundwater outflow, for example, slope, length of the stream, drainage density, stream order, stream frequency on the baseflow recession characteristic or storage delay constant (K) in the watershed. We study how (K) varies with the choice of different estimation methods like using streamflow recession analysis by Brutsaert, (2008) algorithm, our newly developed algorithm for baseflow analysis, and using one of the solutions of Bossinesq’s groundwater flow equation. Using the aforementioned three techniques, the influence of significant morphologic characteristics is found for 56 small watersheds within the large watershed of the Rock River basin over the study period of 1990-2021. Using factor analysis we rank morphologic parameters in terms of their relative influence on (K). The findings of our study suggest that the morphologic parameters that influence the storage delay constant are intercorrelated and play a complex role in shaping the (K) values.