India Rivers Week (IRW) Organising Committee is excited to announce that the theme of the forthcoming annual event IRW 2020 will be: “Is Sand Mining Killing our Rivers?”. As part of IRW-2020, India Rivers Forum is organizing a series of Dialogues (digitally). This includes four regional dialogues focusing on North (Oct 31), South (Nov 7), West (Nov 12) and East (including North East: Nov 21)) India, and the final one (Nov 28) focusing on Sand Mining as a National issue.
Sand mining or mining of River Bed Material (RBM, including sand, gravel, boulders) has a huge impact on Rivers, in multiple ways: physical, ecological, livelihood impacts among others. While sand is also sourced from sources other than rivers, IRW 2020 will focus on sand sourced directly or indirectly from rivers. Sand is by definition, a key ingredient of the rivers. It provides habitat for multiple species of the biodiversity in the river. It provides both sub surface storage space and a mechanism to recharge the groundwater. The sand, along with silt, clay, pebbles and boulders are part of the river and are supposed to reach the deltas and provide a key existential medium in floodplain and deltas. To achieve that, sustaining river connectivities is very important.
Continue reading “DRP NB 19 Oct 2020: India Rivers Week 2020: IS SAND MINING KILLING OUR RIVERS?”
Dams and reservoirs make rivers sediment-starved and menacing manifold downstream. While heavy rainfall is also a key factor behind the floods, hungry water had a more pronounced effect, says D. Padmalal, Scientist and Head, Hydrological process group, National Centre for Earth Science Studies.
– “When the sediment transport is interrupted, the potential energy of the hungry water released from dams will scour the river banks downstream, uprooting trees or riparian vegetation and damaging bridges and other engineering structures,” explains Dr. Padmalal. Overloaded with silt and clay from the eroding river banks, the highly turbid and viscous water clogs drainage channels. Subsequent discharge of water from the dam will lead to inundation and waterlogging of large areas.
– Hungry water can also develop in high gradient river channels devoid of adequate quantity of sand and gravel, especially during periods of high rainfall. “Years of uncontrolled sand mining have left most of the rivers in Kerala depleted or exhausted of sand and gravel. This creates a situation similar to the release of hungry water from dams,” notes Dr. Padmalal. When the river channel has adequate supply of sand and gravel, the potential energy of the water is used to transport the mixture. The water does not scour the banks or turn muddy.
Continue reading “DRP News Bulletin 1 October 2018: Hungry Water Effect due to Dams & Unsustainable Sand Mining Worsened Kerala Floods”