Peripheral Ring Road to ravage TG Halli catchment area

BDA has floated global tenders for the construction of the 100-metre-wide road that seeks to join the NICE road at both ends

The latest Environment Impact Assessment (EIA) report for the Peripheral Ring Road (PRR) says that 13,355 trees to be removed for the 73.5-km road are located in the catchment area of the Tippagondanahalli (TG Halli) reservoir, affecting the hydrological regime and water quality.

The Bangalore Development Authority has floated global tenders for the construction of the 100-metre-wide road that seeks to join the NICE road at both ends to provide a bypass ring road. The EIA report (a part of which DH accessed) is the first in the several steps the BDA has to follow to get environmental clearance for the project while the acquisition of 7.91 hectares of land in Jarakabande Reserve Forest needs clearance from the Union environment ministry.

The third revision of EIA report was necessitated by the change in length of the road from 65.5 km to 73.5 km and an increase in the amount of land to be acquired from 733 ha to 1,063.51 ha. Interestingly, the total number of trees to be removed for the project has come down from 33,838 to 32,175.

However, the number of trees that will be affected in the catchment area has shot up from 9,300 to 13,355.

The removal of 32,175 trees will lead to the loss of carbon sequestration capacity of 3,728 tonnes, directly affecting the air quality and contributing to global warming. The pollution caused during the construction phase, including dust, will affect residents and animals, the report said.

The water from the catchment area was originally a source to Bengaluru, but the increasing urbanisation which entailed change in land use, has been a major cause of its destruction over the last two decades.

It said 7,113 of the 13,335 trees in Thippagondanahalli catchment area were eucalyptus trees. Removing the remaining 4925 trees, it said, will affect the hydrological regime and water quality in the catchment area.

“Deposition of dust, dumping of earthworks, debris, etc affects the quality of water and may cause blockage of existing drainage. During the construction, the project likely influences the change in the flow pattern of run-off (water) during the monsoon period and causes flooding in the neighbourhood,” it warned.

To a question, BDA officials said mitigation measures will be taken to ensure that the project will not scar the catchment area. “Detailed mitigation plans have been drawn up to ensure that the project will not have any impact after the construction is over. Starting from planting 10 saplings for every tree cut to drainage system and flyover along the six lakes, every aspect of environment impact has been taken care of,” an official told DH.

Thippagondanahalli reservoir has three sub-catchments: Hesaraghatta, Arkavathy and Kumudavathi. A report by experts from Environment Management and Policy Research Institute (EMPRI) in 2017 warned that encroachments and construction, quarrying, sewage discharge and dumping of waste have threatened the catchment area, leading to drastic reduction of its water-yielding capacity.

The EMPRI had also recommended an institutional mechanism to protect sub-catchments by removing encroachments, halting quarrying, stopping the dumping of waste and sewage and preservation of storm water drains.

“Rejuvenating the three sub-catchments can turn Thippagondanahalli reservoir into a major source of water. It will cost a fraction of the Rs 15,000 crore required for the construction of PRR,” an expert said.