(Feature Image: (a) Locations of streamflow gauges with catchment boundaries in six major river basins of Peninsular India, (b) elevation map and mean annual maximum runoff rate (streamflow per unit catchment area), (c) Aridity Index (AI) and (d) Baseflow Index (BFI). The maps in first row are prepared in QGIS (Version 2.14.0 ‘Essen’ (2016), URL: http://qgis.org) and the maps in second row are generated using R (Version 4.2.2 (2022), URL: https://www.R-project.org/). Source: Baseflow significantly contributes to river floods in Peninsular India )

A recently published study, see details given below throws light on the role of groundwater contribution to baseflow in rivers and their flooding in Peninsular India’s river like Narmada, Tapi, Mahanadi, Godavari, Krishna and Cauvery. The found that while baseflow contributes more to river flows, its share in the flood event flow magnitude decreases as surface runoff accounts for a larger proportion of flood discharge on the day of the flood.

Most significant are the findings related to dam induced flood that SANDRP has been writing for long and the finding corroborate exactly what SANDRP has been saying: Sudden releases of water from a dam can raise river levels during extreme rainfall events, especially when the dam is nearly full. The impact of sudden floods is more destructive because people living in nearby areas are often unprepared. Without a dam, floodwaters rise slowly over time, allowing people to take preventive measures. However, sudden floods caused by dam releases offer little or no time to prepare, increasing the risks associated with dam-induced flood hazards. Furthermore, the construction of dams alters the natural regime of rivers, leading to changes in sediment transport and erosion patterns. These changes can heighten the risk of flooding downstream from a dam.

Continue reading “DRP NB 060524: Study on dam induced river flooding in Peninsular India” →