Aside from the growing realization over the perilous loss of groundwaters on account of being the singular source of both potable and irrigation supplies underneath Lahore District, mechanisms for reversal of the same are but non-existent. The strategy needs to account for both land and water resources. Preceding discussion under Part I & II has gone to the extent of recommending a moratorium on urbanization across critical areas of the system, such as in the north and the south and at the same time has called for appropriation of green spaces to protect the recharge potential of the system. This is half the story in recouping the lost watertable regime. The remainder could be realized through controlled water harvest regimes (like well centers), reduced per capita water utilization, intermittent supplies through overhead storages, distribution through closed loops and an effective tier of water accounting from the source to storage to consumer. These interventions would be the focus of discussion in concluding part of this three-part article.
Changing public perceptions about water use is a daunting task. Over the life of municipal services across Lahore, water has always been deemed to be a cheap commodity, with deliberately suppressed tariffs contingent with perceived public opinion. Now, with rising energy costs, subsidies are waning and there is the emergent need to realign the consumer perception. This is two-pronged; not only the total per capita water use needs to be reduced but also the unrealistic emphasis on 24-hr supplies requires curtailment in favour of intermittent supplies. The argument for this intervention is substantive; presently, the system is bestowed with all kinds of uncertainties, including the volume of water being abstracted. There are no valid estimates of water produced and consumed within WASA and almost none within the Non-WASA regime. A fixed per capita water demand at 35 gallons for the urban populace (and 20-25 gallons for the peri-urban environment) would permit less operation of tubewells. Contingent to this fixation of supplies, the distribution needs to be routed through overhead reservoirs that would store the pumped water and permit controlled releases.
The undertaking of a Water Demand Management Program to save water through the efficient use of water is not a luxury but an absolute necessity. Reducing the amount of water consumed, while maintaining the level of benefit to the customer can greatly reduce both the consumer and utility costs. Lahore WASA can save money, because reducing demand effectively creates more system capacity.
Rationalized water demand is tailored both to the existential and potential capacity of the end user to consume water and is a means to conservation of water within the system. By decreasing demand, a water utility can help avoid investments in new facilities and equipment. The consumer benefits from demand reduction through the reduced cost of delivery, the diminished chance of water shortfalls at source, and the decreased likelihood of major investment expenditures. Although some utilities are wary of demand-side programs that may affect revenue, in most cases, both the short and long-term savings from demand-side programs far outweigh costs.
Peak day demand is a particular cause of worry for the water managers. Presently for Lahore WASA there is no operational redemption in terms of flexibility of operation….water abstracted immediately becomes part of the grid network. Release of controlled supplies from the overhead reservoirs ensures line pressures under constant gravity-heads. The storages, acting as balancing reservoirs, effectively obviate the need to increase the density or operation of tubewells.
With tubewell connectivity exclusive to the reservoirs, the number of operating units and the capacity of each is also curtailed. Generally, for potable water abstraction, 1.5 to 2.0 cusec capacity tubewells are installed. This is the norm across other municipal operators within Lahore. Only WASA has installed 4 cusec wells since 1967 on the recommendation of foreign consultants. The declining watertables, wastage of water and higher cost of pumping warrant reduction in the capacity of tubewells towards financial viability. Besides, it has been experienced that discharge of tubewell rapidly reduces from 04 to 02 cusec in a span of 5-8 years despite use of strainers of different materials such as stainless steel, copper, PVC and fibre glass.
For areas particularly devastated by falling water tables, there is but no option to freeze the operation of tubewells within the existing service areas and re-arrange supplies through water transmitted from outside the system, such as a well center. The size and location of a well center, typically producing 50-150 million gallons per day of potable underground water, is affirmed through numerical modeling and, for Lahore, suitable sites have already been identified in the northeastern corner of the District.
The viability of a well center is established based on the inflow-outflow regime native to the environment and the projected depletion of the watertables over extended years of operation. A well center typically comprises a battery of suitably spaced pumps that abstract groundwater in unison for transport to the geographically recessed civic service areas through transmission mains. Water imported from a rich harvest regime obviates the need for local pumpage and negates the loss of underlying groundwaters.
Invariably, installation of a well center is a decision for the host Agency and subject to substantiated evidence of the constraints and benefits. The design for the supporting service infrastructure to the catchment population could then follow based on
- the size of the zonal or multi-zonal population and demand estimation
- number, type/format of source water induction and reservoir control
- metering at both bulk and consumer level
- pipe network adjustments in terms of size and loops
The size of the service area targeted for reform matters greatly since too small a selection would be difficult to replicate in terms of impact analysis and too large a selection would tighten the budget for capital works. With realism in mind the population of a subdivision should not exceed 300,000 persons through reconstitution of service boundaries. The objective would remain to balance supplies against demand through creation of adequate local storage. Overall, the institutional ownership of the selection would matter the most and one that Lahore WASA is able to operationalize ahead of network adjustments.
Finally, towards fiscal control, the system needs to perform under a three-tier arrangement that could be likened to successive levels of internal revenue appropriation. This first tier has to own up the cost of production as the base slab before incremental tariff adjustments could be made downstream of the system. At the second tier, documented supplies from storages are released to subscribers in the zone where Tier-3 staff monitors system flows through in-line bulk flow meters. Water auditing is first reconciled between Tier-1 and Tier-2 for deficiencies at the trunk level before Tier-2 staff can use each hub as a correlating mechanism to the closed loops within Tier-3 to isolate predictive system leakages.
WASA revenue staff is the end point in the stream where consolidated statement of production and loss is reconciled to establish daily system-wide sales and subsequent monthly billing. (concluded)