Groundwater is an important water source and its non-management is generating significant legal and political debate. A change is occurring in the amount of surface and groundwater used for agricultural, municipal, and industrial purposes. Generally, the amount of surface and groundwater used for irrigation is declining while the use of these water sources for municipal and industrial use is increasing. A further decline in irrigation water use is forecast because of existing overdraft situations, anticipated future population growth and unplanned urbanisation. The core groundwater management issues that must be addressed are: 1) How to resolve the conflicts over domestic well interference caused by high capacity wells? 2) How to prevent aquifer overdrafsting and promote safe, sustainable aquifer yields? (3) How to address aquifer mining? When examined in this context, the issues shift from protecting private property rights in ground water to effectively managing aquifers and ground water in order to sustain an agricultural economy that is transitioning to an urban service economy.

Groundwater is hydrologically divided into: 1) Vadose water in the unsaturated zone, and 2) Water in the zone of saturation. In the unsaturated zone, the spaces in the soil or rock contain both air and water generally not available for pumping. In contrast, in the saturated zone water flows freely into wells and springs. The upper surface of the saturated zone is referred to as the water table.

Aquifers are geological formations that can store, transmit, and yield a quantity of water to a well or spring and are of two basic types of aquifers: 1) confined and 2) unconfined. These aquifers respond differently to pumping. Water in a well drilled into an unconfined aquifer will reach the top of the zone of saturation known as the water table. The water table will fluctuate in response to recharge and pumping. A confined aquifer, also called an artesian aquifer, is basically a pressured water stratum. Water in a well drilled into a confined aquifer is under pressure and will reach the potentiometric surface. Pumping of a single high capacity well, or pumping of many wells, can have regionally significant effects on aquifers and groundwater systems and lower the water table. These pumping draw downs can adversely interfere with other wells in the area.

Legislatures need to frame laws, rules and adopt management approaches for provinces to develop a set of options for dealing with (1) well interference, (2) overdrafting, and (3) mining problems. Pakistan is struggling with sustainability issues and need to adopt different management strategies for dealing with the problem. The following types of specialised rules may be adopted after studying problems of cities: A.

Legislative “cap” on withdrawals; B. Conservation by waste reduction requirements and limitations on rights; C. Retiring existing rights to reach level of “safe yield”; D. Moratorium on new wells; E. “Pooling arrangement” with flexible application provisions; F. “Critical township” districts’ well spacing requirements limiting new wells; G. Division into groundwater basins with different powers for management; H. Municipal preference during overdraft; I. Aquifer management by Government Engineer; J. Critical groundwater districts based on overdraft conditions.

Critical area legislation offers the advantage of faster response to problems. The legislature can set forth specific objectives to be attained and specific problems to be addressed by district management. The provinces should provide a comparative snapshot of water use in the Pakistan especially reliance on groundwater for irrigation and public water supply. The Law must create categories of groundwater use in land like non-regulated, non-irrigation expansion, and active management areas (AMAs). The Department of Water Management can limit per capita consumption in urban areas. Several legislative alternatives are available that would protect and conserve groundwater resources. The alternatives are discussed below focus on the above mentioned issues:

Well interference is caused by the pumping of high-capacity wells near shallower low-capacity wells. This pumping generally lowers the water level in the smaller well. The overall lowering of the water table in an aquifer by pumping which exceeds recharge is a third and perhaps permanent cause of well interference. Most of the well interference problems arise when high-capacity commercial, irrigation, or municipal wells are located near small-capacity domestic wells.

Overdrafting of aquifers is a significant problem for sustainable aquifers. This condition results from withdrawing water from an aquifer at a rate faster than its natural, or artificial, recharge rate. If this practice continues for a long period of time, or if the aquifer has limited or little recharge, overdrafting is called mining. The consequences of overdrafting are progressively higher water costs, and possible subsidence, or water quality degradation.

Groundwater mining occurs when withdrawals are made from an aquifer at rates in excess of net recharge over a sustained period of time. In aquifers with little or no recharge, sustained withdrawals will in due course exhaust the supply or lower water tables below economic pumping limits. To the degree that groundwater is mined, flexibility to respond to future dry spells and droughts is lost. Several countries have provided for controlled mining of aquifers so that depletion occurs over a predictable number of years. The choice of time periods usually reflects a legislative policy judgment. A long depletion period preserves water for future uses but usually requires severe restrictions. The aquifer is recharged by precipitation on the surface and seepage from streams crossing the outcrop area. The rate of natural recharge is estimated to be sufficient to sustain present levels of pumpage from the aquifer; however, in heavily developed areas withdrawals must be limited to quantities equal to local area recharge, otherwise the water table will be lowered further and additional subsidence will occur. In some areas where the aquifer is essentially undeveloped, substantial volumes of potential recharge are rejected. Problems related to withdrawal of water from the Gulf Coast Aquifer are: (a) land surface subsidence, (b) increased chloride content in the water of the southwest portion of the aquifer, and (c) salt-water encroachment along the coast.

The following options can be worked to address the aquifer sustainability issue: 1) Establish statutory descriptive standards for aquifer sustainability based on optimal safe yield criteria. The safe yield criteria could later be numerically defined by groundwater availability models as tempered by economic, environmental, and social factors. The standards would bring predictability and consistency to the management of aquifers by local groundwater districts while giving them flexibility in local means of implementation. Monitoring and reporting requirements could be established to insure that local districts conform to the provincial goal of aquifer sustainability. 2) Grant authority to the Department of water to set descriptive standards for aquifer sustainability based on statutory optimal safe yield criteria. The standards would bring consistency to the management of aquifers by local groundwater districts while still giving them flexibility in local means of implementation. Monitoring and reporting requirements could be established to insure that local districts conform to the Federal/Provincial goal of aquifer sustainability. 3) Establish aquifer-wide, regional, or sub-basin districts to coordinate planning and management and integrate the efforts of local groundwater management districts into the regional management district’s planning authority for the aquifer. 4) Allow for the continued legislative establishment of local groundwater districts. 5) Place a moratorium on the establishment of additional local groundwater districts until ground water availability models can be run on the major aquifers. This option would allow for the establishment of districts based on integration into an aquifer-wide plan. None of the above five options would preclude the creation of local groundwater districts, but they would require that all districts operate under uniform sustainability standards for aquifers. Districts would have the ability and authority to apply local insight and knowledge in aquifer management, but they could not operate under different or inconsistent sustainability standards.

The impact is not restricted to aquifers; groundwater pumping can also result in a number of changes to ecological resources which include reduced river flows, lower lake levels and reduced discharges to wetlands and springs. These ecological changes raise concerns about drinking water supplies, endangered species, riparian habitats, and migratory species. Greater attention is now given to the sustainable management of groundwater through laws. The problems of well interference, aquifer over drafting, and mining, If left untreated, will lead to short and long-range negative economic, hydrologic, and social consequences for future generations

Save the planet, because we have nowhere else to go to.

 

The writer is an Advocate of law.