Assessing the Current Status of Surface Water Hydrological Monitoring System Over Some Major Vietnam’s River Basins

Abstract

Observational streamflow records in river basins play an important role in hydrological research, flood and drought forecasting, and water resources management. However, current streamflow records in Vietnam still have many limitations in terms of continuity and harmonization among different sources (including conventional and automatic stations). This study analyzes the completeness of available streamflow data and assesses the spatial density of streamflow gauging stations across the major river systems of Vietnam. The study synthesized information on streamflow gauging stations and computed basic statistical indicators for classifying stations by record length. The study also applied GIS to analyze the spatial density of streamflow monitoring network for both the current period and the planned network under Decision No. 90/QĐ-TTg issued by the Vietnamese Government for each river system. Among the major river systems in Vietnam, the Red -Thai Binh river system has the largest number of hydrological monitoring stations (29 stations) and a relatively longest number of monitoring years (over 60 years). The remaining river systems generally have relatively adequate data series, but the number of stations remains limited, which were insufficient to satisfy recommended density standards. Mean inter-station distances across the river systems ranged from 38 km to 124 km, with the exception of the Vu Gia–Thu Bon and other minor river systems, which recorded mean inter-station distances of 28 km and 27 km, respectively. The findings of this research may provide essential baseline information to guide the strategic planning and development of hydrological monitoring networks, thereby supporting water resources research and forecasting capacity in alignment with Vietnam's sustainable development goals.