Rain runoff from NHs to recharge groundwater

The runoff water from the roads and built-up areas of national highways in the state will soon have rainwater harvesting and groundwater recharging infrastructure as the Ministry of Road Transport and Highways (Morth) has told officials to strictly implement the guidelines issued in 2013.

Stating that the surface run-off water from the roads was huge in quantity, the Morth had, in September 2013, emphasised on the need to build RWH and groundwater recharging infrastructure as the NH network across the country was growing exponentially.

Based on the 1,100 mm annual average rainfall for the country, officials had estimated that a 1 km stretch of national highway will have 61.6 lakh litres of runoff water. Besides the roads, toll collection booths and local offices of NHAI and its contractors/concessionaires should also build such infrastructure.

Of the 1.31 lakh km of NH network in the country, Karnataka has 7,334.8 km. The runoff water from the road stretch in Karnataka is nearly 1.5 tmcft, enough to meet the water needs of a metropolitan city like Bengaluru for a month.

However, the circular, with tentative guidelines, had been put on the backburner till recently. Last week, the ministry has issued fresh rules directing officials to prepare detailed project reports containing details of locations of the RWHs and artificial recharging structures.

When it comes to implementation, executing agencies and officials have been told to issue work completion certificate to contractors and concessionaires maintaining the roads, only after confirming that such infrastructure is functional.

"Periodic cleaning and maintenance of such structures/arrangements to ensure their proper functionality shall also be part of the maintenance contract, during the operation period," the latest circular states.

The location of water harvesting/recharging arrangements will be decided based on the data of rainfall intensity and geo-technical details. While the Indian Road Congress has issued a guideline in this regard, the ministry has issued a general rule to be adopted in cases where guidelines are absent.

Accordingly, recharging wells of 0.5-metre diameter and 10 to 15-metre depth will be built for every km on each side of the highway.