Kochi: Drinking water supply to lakhs of houses in parts of Ernakulam district, including in the Cochin Corporation area, could be crippled if saline water enters the Kerala Water Authority's (KWA) pump house at Aluva via Periyar river. Already the KWA is pumping 20% less than the usual quantity of water from the facility. Adding to concern, water level in the the Periyar river has sharply dropped and stood at a metre below the sea level during the low tide the other day.
Two shutters that prevent salinated water from entering Periyar have been clogged entirely by garbage brought by floodwaters. The water-purifying facility will be rendered useless if salinated water gushes in during the high tide. The pump house has the equipment to remove silt in water, but it can't do anything if salinated water enters. It can affect cultivation and drinking water supply seriously.
Saltwater can easily reach the pump house, which is located just 8 km from the coast. If the high tide is intense, seawater can reach the KWA facility in hours. As the difference between water levels in Periyar and the sea has been going down in the past days, the possibility of saline water intrusion is reduced. While the Periyar level was below 90 cm on Tuesday, it was 20 cm on Wednesday.
The daily pumping used to be 290 MLD (million litres per day), but is less by 20% now. Seepage of brackish water can still reduce the quantum of water supply.
Silt too
Aluva pump house has all the facility to remove silt. Silt is found deposited in the intake well that collects raw water at the pump house, but it doesn't pose a major threat. A small dredger was to be brought from Kothad to remove the silt, but the work has been delayed because the repair of Kothad pumping house is not over yet.
The level of silt in water during the flood was 430 Nephelometric Turbidity Unit or NTU. It has come down to 12 by Wednesday. The water is purified to keep the NTU below 5 before it is pumped.
Protection mechanism
The Periyar river branches out into two from near the Aluva bridge. A regulator is at Purappillikavu where a tributary flows towards Kottapuram area, and the bund at Pathalam is on the stream that flows towards Cheranallore. The regulator as well as the bund are lying open since the recent flood. Brackish water had started flowing into Periyar before the November high tide as the shutters of the facility do not close firmly.
a) Regulator-cum-bridge at Purappallikavu
The regulator-cum-bridge was built at Karumaloor Purappillikavu to prevent salinated water from the backwaters from flowing into the river. However, the construction had been poor despite the crores pumped into it. On top of it, the flooding piled up trash, leaving the shutters partly open. The regulator-cum-bridge has 24 shutters. Many of them lie open since the flooding, allowing saline water to flow in. Most of the shutters were downed on Wednesday following complaints, but the inflow of brackish water has not been arrested entirely as the shutters haven't closed firmly.
The regulator itself, opened over a year ago, still functions on hired generator.
b) Regulator-cum-bridge at Pathalam
All the 13 shutters and the only shutter lock here remain open, as they cannot be closed. Tree debris that had landed on the shutters were removed the other day. The shutter control room was entirely inundated in the flood and electric panels were completely destroyed as silt accumulated. The generator was saved from damage as it was shifted to the bridge.
The panel board could be repaired after a week. The generator needs to be shifted back to the control room so that the shutters can be operated. The motors also need repair. The lock shutter cannot be used now as the contractor has taken away some machine part.
The shutters can be reactivated only if the irrigation department acts swiftly. The electrification of the regulator is also pending.
The salinated water is gushing in 87 cm higher than the Periyar water level. The receding water level in the river and the weak flow have helped its inflow. The brackish water can first affect the Muppathadam pump house, which is just 5 km away.
c) Regulator-cum-bridge at Manjummel
Three of the nine shutters have been kept open at the regulator-cum-bridge, built to prevent salinated water from entering Muttar river, a tributary of Periyar. Water is gushing in from the backwaters through the opened shutters. Increased salinity in the Muttar river would affect the industrial area and water supply to Eloor.
Areas facing water crisis
Several households will be deprived of drinking water supply. The Aluva KWA pump house supplies water to Vypeen area, Cochin Corporation area, Aluva, and the panchayats of Choornikkara and Keezhmadu.
Salinated water entering Muppathadam pump house would cripple water supply to Kodungallor, Alangad and Karumaloor panchayats.
Water supply would be affected to establishments like FACT, TCC, HIL, Apollo, Cochin Refinery and Amruta Hospital if saline water reaches via Manjummel bund.
