The Defence Housing Authority (DHA) in Karachi has taken a futuristic step by deciding to put hi-tech polyvinyl chloride (PVC) pipes in place of traditional reinforced cement concrete (RCC) ducts. This is being done in Phase VI for storm water drainage system. These pipes can be used for sewerage systems as well.
Traditional storm water drainage system requires fabrication of rectangular RCC channels and curing for 14 days before usage. Their flat cover follows the same routine.
Trenches are excavated and levelled, RCC channels are lowered, each RCC channel is aligned and joined and top covers are installed.
A length of 100 feet takes about 30 days after the RCC channels and top covers are fabricated and readied with 14 days of curing. During this period, the residents and businesses suffer.
On the contrary, these unique and lightweight PVC pipes are made on-site; in 50-foot length at a time.
Joining of the two pipe lengths takes less than an hour and backfilling can be done imme-diately afterwards. Several hundred feet of pipes can be laid, joined and back- filled within a day.
These pipes are also ideal for sewerage. The pre-partition RCC sewerage pipes are typically four feet in diameter which was good enough for the size of population in 1947. With urbanisation since then and increase in population, these pipes are severly overloaded.
Finding overflowing sewerage on M.A. Jinnah Road and I.I Chundrigar Road is quite common. Those RCC pipes can be replaced by these PVC pipes easily, quickly and economically.
This novel approach by DHA Karachi to resolve the long-pending storm water drainage issue inthe area will provide an ideal and a quick solution to others across Pakistan. Well done, DHA!
S NAYYAR IQBAL RAZA
KARACHI
