What’s the deal on rainwater flooding?

July 5, 2020

Lahore has long struggled with rainwater flooding, water stagnation and drainage issues during monsoons. This year, Wasa claims to have foolproof plans in store

According to the Wasa spokesperson, the formerly identified 30 sore points in Lahore have been reduced to 22. — Photos by Rahat Dar

Lahore’s catchment areas receive an average annual downpour of 629-670mm. According to an estimate, 74.7 percent of the rainwater comes about in the monsoon season. It causes flooding and water accumulation besides throwing daily life upside down, as people are trapped indoors. The low-lying areas, in particular, are flooded massively.

The Water and Sanitation Agency (WASA) has long struggled to map out strategies to fight flooding, mitigate water stagnation time and drain out the storm-water during monsoon. In some cases, it has found success. But the ordeal isn’t over yet.

This year, Wasa has come up with what it calls Monsoon Action Plan 2020. It involves a number of projects — chiefly, Lawrence Road Reservoir Project and Storm Water Drainage System which cover the area from Haji Camp to the Ravi River.

Spanning over 24 acres of catchment area, Lawrence Road, which lies in close proximity to the Board of Intermediate and Secondary Education building, is a known ponding point. Whenever it rains, the site is submerged. Rainwater runoff flow leads to long water stagnation time. Under Wasa’s MAP 2020, the administration has built a reservoir (big underground trunk) at the Baghe Jinnah. This has a capacity to store 1.5 million gallons of water. Most of the rainwater in the area will thus rush towards the reservoir. This will help clear water accumulation quickly. Later, the storm water will be used to irrigate the Baghe Jinnah gardens.

Under the Rs 3.2 billion Haji Camp Drain project, storm-water will be transported to Ravi River via Lakshmi Chowk, McLeod Road, Nabha Road, Chauburji and Shaam Nagar. Two sections of drains — one running from Haji Camp to The Mall and the other from Jain Mandir to Chauburji — have been made functional.

Wasa Managing Director Syed Zahid Aziz says that it is hoped on account of the new arrangements that Lakshmi Chowk will have no standing water: “The disposal station has been connected to two Wapda feeders. If one of them suffers a power outage, the second feeder will keep the disposal station working. In case both are shutdown, a generator will kick into action. With new preparations in place, the disposal station shall remain functional and rainwater shall be cleared quickly.”

He also speaks of a monsoon control room at Wasa’s headquarters and 30 emergency camps in various localities. Storm-water management he says “involves operations of disposal stations, ensuring flow of channels and dewatering operations from low-lying pockets, and comprehensive monitoring and placement of machinery on critical points.”

According to details available with TNS, Wasa has received around Rs 1.6 billion for the project.

Besides, fresh Standard Operating Procedures (SOPs) have been worked out. The Wasa Control Room will team up with representatives from the LDA, the TMA, the LWMC, Traffic Police and the LESCO to ensure a smooth operation. Constant contact with the Met Office regarding rainfall forecast has been formalized. There is a formal dewatering plan and mobile squads.

Storm water management “involves operation of disposal stations, ensuring flow of channels and dewatering operations from low-lying pockets, and comprehensive monitoring and placement of machinery at critical points.”

The SOPs for rain management will ensure effective operation of sewerage pumping stations and manage all water-supply tube wells to curtail the sewage load and deploy suction machines at specified locations. The staff at drainage centres shall ensure immediate remedial action on receiving reports of any emergencies including power failure, inundation and machinery breakdown, and ensure complete drainage of rain for all sore points.

As per the SOPs, the Wasa officials will update rain and dewatering data online.

44 suction machines have been deployed at 14 places including Bhati Gate, Sheranwala Gate, Aik Moria Pul, Lakshmi Chowk, Mozang Chungi, Firdous Market, Civil Secretariat, Cooper Road; Poonch Road, Samanabad; Ichhra, GPO Chowk, Empress Road, Chowk Yateem Khana, and City Railway Station.

Besides, 15 excavators, 61 dump trucks, 13 crane mounted trucks, 45 jetting machines, 26 water bowsers, 127 dewatering sets and 30 loader trollies are available for deployment.

According to Wasa spokesperson Imtiaz Ahmed, the formerly identified 30 critical points in Lahore have now been reduced to 22, with help from the latest technologies.

Work on yet another project to suppress water accumulation, called Tunnel Boring Mechanism is likely to start this season. The Rs 14 billion project has been sanctioned by the Planning Commission’s Central Development Working Party (CDWP). The Asian Infrastructure Development Bank (AIDB) will finance the project. A sewer line will be laid deep underground. It will have two sections — one from Zafar Ali Road to Gulshan-i-Ravi and the other from Garhi Shahu to Shimla Pahari, LDA Plaza, Faletti’s Hotel, Queen’s Road, Qurtaba Chowk, Chauburji, Multan Road and Gulshan-i-Ravi. After its commissioning, the current sewer line will be converted into a storm-water drain.

An MDPI report observes that due to enormous construction activities the drainage areas may not fully accept rainfall.

A report published by the Multidisciplinary Digital Publishing Institute (MDPI) on Lahore’s rainwater torments claims that a comprehensive drainage network comprising main drains along with secondary and tertiary drains exists, in order to cope with rainfall runoff.

“However, with population influx and enhanced construction activities, the drainage system has been overburdened,” the report adds. “Unfortunately, the influx of population in surrounding areas finds convenient the disposal of sewage into these carriers. Accordingly, the sewers load the drains throughout the year while storm-water flows are carried during the rainy season (three months in a year). As such, the original storm-water drains have now become sewage drains. Under the existing conditions, the combined flows during dry and wet weather are drained from the hose connection in the streets up to the drain in the area.”

The MDPI report also observes that due to enormous construction activities the drainage areas may not fully accept rainfall runoff. Consequently, rainwater swamps the streets, parking lots, roads and paved areas, and becomes part of the sewage and drains causing overflows.

The writer is a freelance journalist

What’s the deal on rainwater flooding in Lahore?