Watershed approach for studying soil preferential flow: A case study

Abstract

Preferential flow (PF) is a generic term used for water flow paths through biopores, fractures and macro pores. Many studies and models were already established to describe the PF. In semi-arid regions, the connecting aboveground and below ground processes to investigate how soil redistribute rainfall and nutrient and their impact on subsurface flow, is a fairly overlooked phenomenon. In this era of fast changing climate, erratic rainfall and rain water management, soil constitution plays an important role. In semi-arid regions, watershed is the basic hydrologic unit which gives study of the soil preferential flow a holistic look. In this regard, a study was conducted in Hayath nagar micro-watershed, Hyderabad, during 2020-2021.results revealed that the micro-watershed mainly comprises of heterogeneous matrix flow and fingering at surface while at sub surface macropore flow with low and mixed interaction prevails. This suggested that subsurface soils were mainly responsible for spatial redistribution of flows and generating lateral flow than vertical flow. Thus, the watershed under study requires better management practice to harvest water and check runoff at the time of high intensity rainfall. The results and the methodology of the present study have relevance in studying the preferential flow of diverse watersheds.