Contribution of Baseflow to River Streamflow: Study on Nepal’s Bagmati and Koshi Basins

• Published in: KSCE journal of civil engineering Vol. 22; no. 11; pp. 4710 - 4718
• Main Authors: Bastola, Shiksha, Seong, Yeonjeong, Lee, Daeeop, Youn, Ilro, Oh, Sewook, Jung, Younghun, Choi, Gyewoon, Jang, Dongwoo
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Civil Engineers 01.11.2018; Springer Nature B.V; 대한토목학회
• Subjects: Base flow; Basins; Civil Engineering; Climate change; Construction; Dry season; Ecological monitoring; Engineering; Environmental engineering; Environmental regulations; Geotechnical Engineering & Applied Earth Sciences; Graduate students; Groundwater; Hydrograph analysis; Hydrographs; Industrial Pollution Prevention; Monsoons; Precipitation; Prevention; River ecology; River networks; Rivers; Seasons; Stream discharge; Stream flow; Surface water; Water conservation; Water quality; Water Resources and Hydrologic Engineering; Water shortages; Water supply; Watersheds; Wind; 토목공학; Nepal; baseflow; baseflow index (BFI); water management; Nepal; streamflow; seasonal trend
• ISSN: 1226-7988; 1976-3808
• DOI: 10.1007/s12205-018-0149-9

Understanding the role of baseflow is important for efficient river management. Hydrograph analysis separates baseflow from varying streamflow hydrographs. Separation of baseflow from streamflow and its analysis are crucial to flow regulations, water quantity, quality, and supply, and habitat. This study attempted to identify the annual and monthly contributions of baseflow on streamflow in Nepal. For this, the three techniques of WHAT, BFLOW, and HYSEP were implemented to separate baseflow from streamflow in two watersheds (the two basins). As a result, baseflow’s contribution is high in the post-monsoon (October and November) and winter seasons (December-February). The Baseflow Index (BFI) slightly decreases in value in the pre-monsoon (March-May) season; in the monsoon season (June-sept), the range of the BFI is at its lowest. As baseflow’s contribution exceeds 45 percent in all seasons, proper assessment of baseflow is crucial to efficient management of river ecology.