(Feature image: Delta Land Loss Mechanisms. Source Wikimedia Commons)
A new study this week has reminded us what has been known for long. Dams not only store water but also trap the sediment flowing in the river. Whatever smaller quantity of water flow from dams to downstream areas, has much lower or no silt. A lot of that silt was supposed to reach the coast, helping fight against the erosion of the coast due to sea tides and waves. With drastically lower sediment reaching the coasts, higher coastal erosion is the result. While climate change is definitely contributing to the increased coast erosion due to more frequent and higher intensity storms from the sea, the role of dams tend to work as force multiplier in increasing the coastal erosion due to less sediment reaching the coasts from river.
While a new study by a Pune University has highlighted this phenomena in case of Godavari river, peninsular India’s biggest river, this is also happening at most other rivers and where they meet the coasts. As in case of Farakka, closer the terminal dam is to the coast, greater is its effectiveness to trap the river sediment and higher is its contribution likely to be to the increase in coastal erosion.Continue reading “DRP NB 1 Aug 2022: Dams reduce sediment load in rivers leading to higher coastal erosion”