LAHORE: The authorities are planning to launch the “Rainwater Harvesting Project” to address the issue of depleting underground water table in Lahore just as India has already done successfully in New Delhi and other cities.

Dawn has learnt the project, being worked on jointly by the Lahore Development Authority (LDA), Water and Sanitation Agency (Wasa) and the Urban Unit, a subsidiary of the Planning and Development Department, will help raise the water table that is going down by over one metre per year.

Wasa has also proposed some amendments to the LDA Building and Zoning Regulations-2007 to encourage the rainwater harvesting.

“The rainwater harvesting is the collection of rainwater directly from the surface it falls on.

This water is either going directly into the Lahore’s drainage system or lost through evaporation and transpiration. Once collected and stored it can be used for non-portable purposes.

These include toilet flushing, garden watering and clothes washing. Another big advantage of the rainwater harvesting is recharging the aquifer/groundwater,” reads a proposal-cum-study forwarded to the LDA director general by Wasa a couple of days back for approval in the next meeting of LDA’s governing body.

It says the artificial recharge to the groundwater is a process by which the irrigation reservoir is augmented at a rate exceeding that obtained under natural conditions of replenishment.

“Since Lahore and its surrounding areas are located over an extensive water aquifer, the water supply in the city is purely based on groundwater.

The water is pumped out and released directly into the distribution system through 484 tube wells owned by Wasa and over 1,200 being run privately.

Due to ever increasing number of tube wells, the water table is depleting rapidly,” the study states.

For rainwater harvesting, there is also a need of amendments to the building and zoning regulations of the LDA to encourage practices adopted in New Delhi and other Indian cities.

This will not only be helpful in reducing the sharp decline of water table but will also help Wasa reduce massive expenditures on disposal of rainwater.

“In order to encourage the water conservation practices, provision of water tank while constructing five-marla buildings must be declared as mandatory in the city,” the proposal mentions besides other amendments regarding rainwater harvesting.

Under the proposed amendment which was earlier related or limited to provision of water tank/reservoir in seven-marla house/building or above alone, the five marla houses/buildings have also been included in the schedule to have water tank/reservoir.

According to newly proposed section 6.6 (6), all buildings to be constructed in future in Lahore should have provision for rooftop rainwater harvesting. Collected rainwater may be utilised for all purposes other than drinking.

“For each and every house, having area of five-marlas or above provision of rainwater harvesting system is mandatory.

Every house is required to have a storage tank of capacity, as described in the schedule above the ground level. The houses (to be constructed in future) measuring 5 to 6.9 marla, 7 to 9, 10, 10.1 to 15, 15.1 to less than one-kanal, one kanal, 1.1 to 2-kanal, 2.1 to 3-kanal, 3.1 to 4-kanal, 4.1 to 5-kanal, 5.1 to 6-kanal, 6.1 to 7-kanal and 7.1 to 8-kanal will have 300, 450, 500, 600, 800, 1,000, 1,700, 2,500, 3,400, 4,000, 5,000, 6,000 and 6,800 gallons water storage capacity tanks, respectively,” the new section mentioned in the proposal.

The section also mentions connections of rooftop drainpipe with the sewerage system or to the street, rainwater harvesting from houses to recharge the aquifer, public buildings, parks and garden, maintenance of the rainwater harvesting system, approval of building plan of the rainwater harvesting system and inspection of the system.

Talking to Dawn, a senior official said the proposal would be discussed with all the concerned, including the technical and legal experts of the LDA.

“As soon as the authorities discuss and approve this, the preparation for launching the project and introducing new amendments and additions in the regulations will start,” the official said, adding that under the project, the technical experts were also planning to carry out various pilot activities at the important spots of the city.