Trans-boundary aquifers in the State of Punjab, India, along Pakistan Border

Abstract

Insatiable demand for water resources has increased manifold with growth of civilizations. The huge stress on water resources is due to increasing demands and declining water levels, growing vulnerability from floods and droughts, and eco-hydrological problems. Water resources management need comprehensive strategies for providing water of adequate quantity and protecting mankind from adverse impacts. Sustainable solutions for trans-boundary water aquifer systems are therefore of high priority since nature does not draw its boundaries to coincide with the political boundaries.

Punjab state is one of the most prosperous states of India with an agricultural based economy. The total water requirement of the state is 61.675 BCM. Against this, the water availability is only 17.54 BCM of surface water and 23.78 BCM of replenishable ground water resources. Punjab has a very long international boundary and the ground water aquifers are contiguous across the border too. Whereas the majority of the recharge areas lie in the hills of J&K and Punjab, the discharge areas extend to Pakistan too.

It is thus felt that now is the time to study the trans-boundary aquifers of Punjab state in totality and on the basis of proper assessment of ground water contained down to a certain depth (say 1000 meters), decide the allocation of ground water usage by the neighboring countries. The present paper outlines the above along with the hydrogeological set up of Punjab state with special emphasis on Upper Bari Doab area covering the districts of Amritsar, Gurdaspur and Taran Taran.

INTRODUCTION

For any country water is at the core of human interdependence, a shared resource that serves agriculture, industry, households and the environment. Water governance is about striking a balance among these competing users. But water, especially ground water is also the ultimate fugitive resource. Countries may legislate for water as a national asset, but the resource itself crosses political boundaries without a passport in the form of rivers, lakes and aquifers. Trans-boundary waters extend hydrological interdependence across national frontiers, linking users in different countries within a shared system. Managing that interdependence is one of the great human development challenges facing the international community.

As water becomes scarce relative to demand, trans-boundary competition for shared surface and ground water resources will grow. Cross-border waters almost always create some tension between the societies they bind. Because ground water is a flowing resource rather than a static entity, its use in any one place is affected by its use in other places, including other countries.

TRANSBOUNDARY AQUIFER

The key features of trans-boundary aquifers include a natural subsurface path of ground water flow, intersected by an international boundary, such that water transfers from one side of the boundary to the other. In many cases, the aquifer might receive the majority of its recharge on one side, and the majority of discharge would occur in another side. The subsurface flow system at the international boundary itself can be visualized to include regional, as well as the local movement of water. Generally, international boundaries do not follow natural physical features, and water resources can cross them unhindered.

TRANS-BOUNDARY AQUIFER SYSTEM IN PUNJAB

Punjab having geographical area of 50,362 Sq.Km. is predominantly an agrarian State. Nearly 83% of the State’s geographical area is under cultivation with an average cropping intensity of 188% and about 80% of water resources available are used for agriculture sector. Out of the total irrigated area (97% of the net area sown is irrigated), 73% of the area is now irrigated by groundwater through tubewells and the remaining 27% by mostly canals & their distributaries as against 55% and 45% respectively three decades ago. The water needs of the state for various activities, i.e. domestic, industrial, Agriculture, Thermal Power, etc. have been estimated to be 61.675 BCM by Government of Punjab, out of which about 51.81 BCM is for agriculture sector alone. Punjab has been allocated 17.54 BCM of water from its three perennial rivers. Even this water availability has shown a declining trend due to decrease in river inflows during the last three decades. Dwindling surface water resources in Punjab has resulted in over dependence on ground water. The tubewells in the state have grown from 26 thousand in the year 1965-66 to 12.32 lakh in the year 2006-07 and the ground water withdrawal is now 31.16 BCM against total Replenishable ground water resources of 23.78 BCM. There is thus an overdraft of 7.38 BCM of ground water. Despite this, Punjab state is short of 12.98 BCM of its total water requirement.

Hydrogeological Set Up

The State forms a vast tract of alluvial plain formed by mighty rivers, the Ravi, the Beas and the Satluj. Ground water exploration has revealed existence of thick fresh water aquifers throughout the State( Fig-1). These aquifers are laterally and vertically extensive and persistent in nature . However, in south western part the thickness of fresh water aquifer is much less as compared to the other parts because area is underlain by brackish / saline water. The area having prolific aquifers adjoining Pakistan is Upper Bari-Doab, the aquifer disposition of which is depicted through a fence diagram (Fig-2).

A lithological section along AA’ (NE-SW) drawn parallel to the left bank of Ravi river, reveals the presence of 5 to 6 thick permeable granular zones down to a depth of 300-420 m below ground level(Fig-3) The thickness of clay layers varies from 2.0 to 20.00 m and all these clay beds pinch out towards south–western direction except the clay layers occurring between 42.0-63.5 m, 130-140m, 165-170, 212-230m and 282-294m which are persistent. The first aquifer which forms the water table aquifer occurs up to 40-50m bgl and consists of sand with minor amount of gravels and kankar. In the SW part of the section, covering Gujjarpur and Kohala, the phreatic aquifer occurs up to 32-36m bgl. and consist of fine to medium sand. In the NE part, in the water table aquifer gradation from sand to pebbles had been observed. Aquifer material is coarser between 30-50m. The second and third aquifers consist of sand, gravel and pebbles, but and fine to medium sand at places. The aquifer occurring below 230m bgl consists of fine sand and silt at Taragarh and Thathi.

Ground Water flow

Water table elevation map of Punjab state depicts that a water divide runs in NE-SW direction roughly passing through Sirhind, Kotkapura, Muktsar and Abohar. Water table contours are closely spaced in the extreme NE part indicating that ground water movement is fast, in other parts these are widely spaced which show that ground water movement is slow.

The maximum value of water table elevation above M.S.L. is in the NE part having value more than 330 m above Mean Sea Level and the lowest is 165 m above MSL in the extreme SW part (Fig-4). Both the rivers i.e. Sutlej and Ghaggar are effluent in nature. It is also evident from the map that ground water, in general, is flowing towards west and south-west and ultimately crossing over to the neighboring country.

Long Term Water Level Fluctuation

The long term water level fluctuation map of the State, a map (Fig-5) reveals that ground water levels have registered fall varying between 4 and 16 meters in Nawanshahar, Jalandhar, Kapurthala, Moga, Patiala, Ropar, Fatehgarh Sahib, Sangrur, major part of Mansa, northern part of Ferozepur and Bhatinda, Hoshiarpur, Gurdaspur,and Amritsar districts . There is a rise of water levels in remaining area of the state. The rise in water levels is attributed to the continuous seepage of water from network of unlined canals and distributaries and due to the negligible draft from groundwater in the area.

Ground Water Resources

Ground water resources of Punjab state have been computed as on 31.03.2004, and the Replenishable ground water resources of Punjab state have been assessed to be 23.78 BCM, and the net annual draft of the state has been estimated to be 31.16 BCM. There is thus an overdraft of 7.38 BCM . This overdraft has resulted in declining water tables and the blocks becoming over exploited. As per the last estimates, out of 137 blocks in the state, 103 fall under Over exploited category, 5 in critical, 4 in Semi critical and 25 in safe category. Spatial distribution of the block with their category has been depicted in map showing Ground Water Development in Punjab State.

DISCUSSIONS

Water resources, whether surface or underground, have gained tremendous importance in the national as well as international context. Within a country also, due to water scarcities, it is important to assess the ground water that is flowing across the boundaries .In the context of Punjab state, sharing its international boundary with Pakistan falling in the Indus basin, it is all the more important that the disposition and design of the trans-boundary aquifers be studied in detail so as to assess the quantities of water that are flowing across the border.

Based on the available data discussed in the preceding paragraphs, it is established that the slope of the water table is towards west and south-west, which follows land surface slopes. The major recharge areas to the ground water aquifer also occur in the mountains and hills falling in Punjab and J&K. The disposition of the deeper aquifers also indicates that whether these are confined or semi-confined, their slope is towards west. Thus apart from any natural flows that regularly take place due to the difference in the head, any pumping activity that is taking place downstream direction will negatively impact the upstream aquifers. Thus, as a first approximation, ground waters of Punjab are flowing across the international boundary towards Pakistan. The need is to assess and quantify the flows as well as study the chemical quality of the water flowing across. It is also important to assess the long-term behavior of these flows in case of increased pumping due to water shortages all over the region. In case of trans-boundary aquifers across the international boundary no information on aquifer geometry is available so no composite fence of aquifer disposition could be generated as to ascertain the nature and behavioral pattern of aquifers.

However, Central Ground Water Board has taken up study of trans-boundary aquifers within India where aquifers across the states of Haryana and Uttar Pradesh were studied during Upper Yamuna Project. A composite fence diagram across the state boundaries had also been prepared. The main aim of the project was to study the effect of pumping of ground water through augmentation tubewells in Haryana might be having on the Yamuna river flows and ground water resources of Uttar Pradesh. The project used a multidisciplinary approach and some important findings of the Project were:

- Monthly river regeneration between Tajewala to Wazirabad does not show any appreciable decline due to augmentation/other modes of draft.
- Augmentation drafts have local effects in declining the water table but it appears that the same is being recouped by ground water flow to a major extent. Its effect is minimal close to river Yamuna.
- Augmentation draft has only about 20% share from the water table aquifer. Its and other modes of drafts on the water table aquifer in the area studied are negligible.
- The present quantum of ground water draft is having little injurious effect on the unconfined aquifer and can be attributed to:
- Further augmentation draft may be permitted in the area without affecting the river regeneration but that draft must be from deeper aquifers and the allocation of the augmentation draft must be further down the present augmentation canal project. Such a scheme, however, may create local depressions.
- Continuance of the augmentation draft in future may generate decline in water table adjacent to river in U.P. area as well without appreciably declining river regeneration.
- Any large-scale ground water development upstream of the present location of augmentation canal project may effect the river regeneration.

It can be summarised from the above that Central Ground Water Board has the technique and methodology available to study the trans-boundary aquifers. It is anticipated that similar conditions do exist in the trans-boundary aquifers lying across India and Pakistan. Further, recharge area for the aquifers either unconfined or confined do lie in India only except for vertical recharge taking place through rainfall in Pakistan. As mentioned in previous paragraphs, based on the ground water exploration studies in these areas, thick fresh water aquifers have been deciphered on the Indian side of international border and it is anticipated that substantial quantities of ground water do flow across the border. The thickness of fresh water confined aquifers up to the depth explored (300-500m) varies greatly especially in the Upper Bari Doab area. The fresh water aquifers are thick in the North of Upper Bari Doab, where thickness of more than 100 m in the Northern part of the basin is prevalent. In the southern part (Valtoha block) thickness of fresh water aquifer diminishes to less than 50m.

The following steps are required to study the disposition, behavior, potential etc of trans-boundary aquifers ( After: Internationally Shared ( Transboundary) Aquifer Resources Management, Their significance and sustainable management- A Framework Document, IHP-VI, Series On Groundwater No.1, November 2001, UNESCO, Paris 72 pp)

I. Identification of Transboundary Aquifers
II. Spatial Distribution Of Parameters
III. Ground Water Hydraulics Of The Aquifers
IV. Management Issues
V. Pre-Requisites for Sound Management

I. Identification Of Trans-Boundary Aquifers

In contrast to surface water that is easily identifiable, ground water aquifers are poorly known and recognized. It is thus essential to view the entire trans-boundary aquifers, including all that are hydraulically connected directly by lateral or indirectly through vertical contact or through fractures and low permeability formations. For this data sharing amongst the countries is very important. The data gaps can then be identified and filled by carrying out further scientific studies in the area.

II. Spatial Distribution of Parameters

There are some parameters and factors that affect the behavior and development potential of aquifers and need to be studied. These are:

- Hydraulic parameters
- Rainfall and Recharge Zones
- Confined and Unconfined areas
- Natural discharge zones
- Present and planned ground water development zones
- Water quality, potential risks of its deterioration; and
- Vulnerability to polluting agents

In transboundary aquifers, one or more of the above factors may be more important than the other on either side of the boundary.

III Ground Water Hydraulics of the Aquifers

The ground water flow changes when an aquifer is placed under stress by pumping out water from it. This is in response to the changes in the piezometric heads due to pumping. However, this may lead various consequences as:-

- Modification of the ground water flow pattern : Ground water flow passing an international boundary cannot be measured directly. It is estimated from parameters like transmissivity, hydraulic gradient, cross section etc and through mathematical models. Abstraction on one side of the border may alter the flow through the border.

- Modification of the piezometric surface : Ground water abstraction through wells results in modifications of piezometric heads in the form of a concentric cone of depression. These cones of depression may extend across international borders.

- Deterioration of the water quality : Ground water of the aquifers are also affected due to development. Saline water ingress from coastal areas can increase and in inland salinity areas due to upcoming saline water may intrude the otherwise fresh water aquifers.

- Pollution : Anthropogenic pollution can result in aquifer pollution and the polluted ground water may travel to the other side of the international boundary.

IV Management Issues

So far there are no agreements on sustainable management of trans-boundary aquifers, especially in the Indian sub-continent. Sustainable management of the ground water resources requires a multidisciplinary approach even for the international aquifers. There might be a need of agreement between countries sharing aquifers to preserve the natural outflows and abstracting ground water equivalent to the average annual recharge. Even in aquifers having large storages, the amount and rate of extraction should be subject to multilateral agreements.

V Prerequisites for Sound Management

The UNECE (United Nations Economic Survey for Europe) survey of transboundary aquifers and other studies have confirmed the need for having a unified and consistent knowledge base as a prerequisite for the management of transboundary aquifers. Ideally this should be developed within a conceptual model of the whole transboundary aquifer, providing a firm foundation that supports sound development through risk based management. Determination that a particular rate of groundwater withdrawal or general management plan is sound depends on in-depth understanding of the groundwater system.

This understanding begins with knowledge of basic hydrological processes. Relating this to specific situations requires understanding of the extent and nature of the aquifer, how it relates to other aquifers and hydrogeologic features, how the recharge and discharge of water takes place within the aquifer, and where potential sources of contamination are located. Without such understanding the use of a transboundary aquifer cannot be confidently planned. This conceptual model should be augmented by a consistent programme on both sides of a boundary to monitor basic hydrologic parameters, such as precipitation, groundwater levels, stream flow, evaporation, and water use. The monitoring programme will provide the data essential to generate a quantitative perspective on the status of the groundwater system and to validate the conceptual understanding. The data must be consistent with the conceptual model. If not, the conceptual model may need to be revised.

Good and reliable information is crucial to facilitate co-operation among aquifer stakeholders. All stakeholders should have easy access to good, reliable data on abstractions, water quality, and aquifer water levels. Current information technology allows information to be made available to an unlimited number of users easily and economically. With such an approach it should be possible to establish mutually accepted rules, adopted by all parties, based on a holistic definition of the aquifer system and principles of equivalence of impacts of abstraction.

ACKNOWLEDGEMENTS

The authors express their deep sense of gratitude to Dr S.C.Dhiman, Chairman, Central Ground Water Board, for having provided the guidance in writing of this paper. The authors have drawn lots of information from the Framework document – Internationally Shared (Trans-boundary) Aquifer Resources Management prepared by IHP, even to the extent of quoting the document verbatim at a few places. Several reports of Central Ground Water Board for Punjab state were also consulted and the data contained in those reports was generated, analyzed and interpreted by several colleagues. The efforts and contributions of all the colleagues is gratefully acknowledged.

Sushil Gupta
Member(SM&L), Central Ground Water Board, New Delhi
Sanjay Marwaha
Suptd Hydrogeologist, Central Ground Water Board, Lucknow