Interlinking Araniyar and Kosasthalaiyar will tackle flood:Thiruppugazh panel
CHENNAI: In a bid to reduce seawater intrusion in acquifers and to mitigate floods, a canal linking the Araniyar and the Kosasthalaiyar transferring floodwater either way between the two river-basins was suggested by the Thiruppugazh Committee report submitted to the state.
The interim report, which was submitted last year, said alluvial aquifers of Araniar - Kosasthalaiyar are being heavily exploited to meet part of the cities’ water supply as well as irrigation for the last 35 years. This has resulted in lowering of groundwater below sea level which led to seawater intrusion.
Though the pumping from the well fields belonging to the cities’ water supply agency completely stopped in Minjur and Panjet during early 2000’s, this did not result in considerable recovery in the aquifer. According to sources, Anna University had also recommended creating a link (contour canal) between the Araniyar and the Kosasthalaiyar to transfer floodwater either way between the two river-basins to mitgate seawater intrusion while also mitigating floods.
By interlinking the rivers, the extent of seawater intrusion will decrease by about 1 km by the year 2030 and groundwater will increase from 0.5 m to 1.2 m in the upper aquifer with assumed interlinking of rivers by 2030, Thiruppugazh report said.
“In the lower aquifer, groundwater will increase from 2 m to 6 m by 2030. The interlinking is expected to increase groundwater recharge and mitigate seawater intrusion. The provision of checkdams across these rivers at the downstream side of the link (canal) will enable the storage of water along the entire interlinking channel for a length of 4.5 km which could help in moderating the surplus flow during monsoon.
The report said Anna University had identified a suitable alignment to interlink the rivers and a detailed feasibility study and project report should be undertaken.