NO ONE can deny the importance of groundwater monitoring projects in the present scenario of the water crisis in the country. Deployment of the tube-wells in private sector has taken place at a very rapid rate. The number of tube-wells have increased to over 597,000 in the year 2001 against a number of 3000 in 1950.
About 70 per cent discharge of the existing wells is saltish and is playing havoc with soil by developing salinity and sodicity front in fertile soils. No more addition is affordable to an already salt affected area of 8.133 million hectares. In addition to yielding some water quality concerns, the uncontrolled and unregulated groundwater extraction has given rise to a deep water table. The pumpage cost is thus increasing with the depth to water table. It is estimated that groundwater discharge has gone to 37 MAF against its recharge of about 31 MAF in Punjab.
The withdrawal of groundwater level has also touched to 49 million acre foot, while the recharge to groundwater from all sources does not exceed 55 MAF. With this scenario, the monitoring cannot be limited to simply water level measurements and judgment of the water quality on the basis of conventional indictors. The fundamental objectives of monitoring must be agriculture-oriented and designed for benefiting the farming community.
The conventional approach to groundwater monitoring cannot generate a useful database of practical significance from soil management and crop production point of view. The approach needs a relative perfection so as to avoid soil deterioration, protect water quality and benefit clients. With the conventional approach we can not develop any micro or macro groundwater resource picture, neither we can make quantitative assessment of aquifer, nor we can approach salt balance quantification and finally we also cannot move towards sustainable groundwater resource management. The simple approach to groundwater monitoring will no more help us to achieve its optimal development potential for sustainable use. Any type of monitoring that does not come up with such potential out puts will not be more than wastage of both time and money.
Water table measurements are made through installation of piezometers, usually at a depth of 50 feet where water table is shallow. Perhaps beyond this depth limit, installation is no more economical. This depth is considered adequate for keeping an eye on groundwater fluctuation. The water samples are also collected from these piezometeric pipes and analyzed for water quality. There are some people who do not bother about groundwater quality or water table if it is beyond ten feet. Water beyond this depth no doubt does not affect over lying soil strata in fresh zones. But a farmer pumping underlain brackish water beyond this depth may harm the soil.
So in soil surveys an integrated approach is sine qua non. This type of groundwater quality monitoring may be misleading if farmers are exploiting groundwater from a depth greater to that of the piezometer. The water quality of the upper layers of the aquifer may be good, while that of the lower one may be the poor. This has promoted the concept of groundwater skimming where the fresh water overlies the saline one. Such a situation prevails in Kot Momin regions and in some parts of Bahawalpur where upcoming of brackish water has started groundwater quality deterioration in the upper layers of the aquifer.
Therefore, water from farmers’ tube-wells must be sampled, as it is the water, which actually affects the soil and crop attributes. In groundwater monitoring studies no such information under the World Bank or the Asian Bank projects has been mapped out so for on whole Punjab basis. The chemical composition of different aquifer layers needs to be identified for facilitating the concept of ground water skimming.
Another discrepancy noted while going through some technical reports is that water quality is more often evaluated by the EC parameter. It is pointed out that EC denotes only the salinity status of the groundwater. The sodicity, which is worst to salinity and is estimated by RSC and SAR, is not given weightage. So for no map has been delineated to highlight the sodicity problem of the groundwater. It is pointed out that water fit on EC basis may qualify as unfit from SAR and RSC point of view. Need must be felt to develop spatio-temporal information-based maps identifying clearly the high EC, SAR and RSC zones in the Punjab.
Now the field of water quality has been so specialized that apart from conventional water quality indicators, the ratios like Ca/Mg, HCO3/Ca and EC/SAR have become important. Only an expert in line can evaluate their role in soil deterioration. The experts in line know that even water with permissible or negative RSC parameter may sodicate the soil. similarly the water having same EC but different SAR would deteriorate soil to a different degree.
So simply running after apparent conventional water quality indicators and their limits may be of no use in this age of specialization. Wapda about 10-12 years back has prepared an atlas covering both salinity and sodicity of soil but not that of water. Many consultants receiving unbelievable payments have been seen with no specialty in Soil Science but advocating EC. It is so because their consultancy is based on old EC maps available. No further steps are taken on SAR and RSC basis.
This will require a new exercise and a lot of field work. No doubt SAR reflecting sodicity is a function of salinity (EC) but recommendation or consultancy made on salinity basis will be invalid for sodicity of water (SAR & RSC). Both have different management strategy. It highlights the need to map out sodicity (SAR & RSC) of groundwater instead of salinity only. If there is any need to map out EC parameter then need must be realized to digitize a map for SAR & RSC water quality indicators.
Groundwater monitoring projects should also come up with the potential output to benefit the farmers. The crops tolerant to salinity or sodicity of soil and water must be indicated on the maps according to the nature and type of the soil and water quality hazard. No such effort in this direction has been made in groundwater monitoring projects at provincial level. Some people do discourage systematic work on sodicity parameters and their relation to crops. They should do so, because only such output may derogate their trade of consultancy. Water quality indicators including less attention paid SAR and RSC cannot be overlooked any more for rational, scientific and most economic use of the groundwater resource at the juncture, when the policies are shifting from development of groundwater to its management.
Different institutions observe different water quality parameters and standards. This is somewhat confusing. Need is to develop management based water quality standards keeping in view topography and climate change in a region. Different standards should be promulgated for different agro-ecological zones. Different people have different water quality results for the water samples collected from the same locality. No doubt the error locates its root in the expertness of the analysts and efficiency of the instruments but major error comes from mode of sampling and quality of chemicals used in analytical techniques. Need is to fix some quality grades of the chemicals at national level so as to reduce errors in the results and make the result of such projects really useful for the clients.
An agency should also be held responsible for inter-laboratory check analysis. It will help maintain a good water analysis service. In the groundwater monitoring projects, studies have been confined to the level of water balance. No study so far has been executed to work out the salt balance in different irrigation commands of the province. It must be worked out to keep a vigilant eye on the salt flux being added to the irrigated soils. The number of tube-wells, their pumping hours and average salt composition, cropping pattern, crops yield and water supplies may help calculate the salt balance. Such type of database would be useful at all stages of planning and operation of the tube-wells.
No database is available at provincial level, nor any map has been prepared under any project scheme to quantify the aquifer water and rate of groundwater abstraction. Need must be realized to predict time scale effect on aquifer at the rate of groundwater pumpage going on in a particular geographical region. Both the quantitative and qualitative assessment of fresh and saline groundwater resource is must at each micro and macro levels. After quantification of the aquifer, farmers should be informed that how long they can go for safe groundwater extraction. The decisions on cropping patterns may also help in sustainable use of groundwater resources.
So far, farmers have not been provided with any such precautions. Keeping an eye on the groundwater recharge and discharge the decisions should be taken by the groundwater managers to rationalize and regulate groundwater outflow through tube-wells and other skimming well techniques such as Nalka bore wells. In this regard legal regulatory framework may be implemented sincerely to protect both groundwater quality and aquifer as well. Maps need to be designed to show boundaries of saline interface and water intrusion trends into the fresh zone. A study limited to a single area may not be applicable to other parts of the province.
Another potential output that should come from groundwater monitoring projects is development of a sound database in context of modelling of different soil, water and crop characteristics under different scenarios of farm management. Any type of modelling missing any of the soil, water and crop parameters would be of no use to the farmers or other clients for which the groundwater monitoring studies should really be meant. Presently, models such as Indus basin model (IBM), revised IBM, Modflow and other models are in operation for straight water behaviour studies. Effective models like solute transport models need to be integrated with crop yields. LEACHM (1987) model for example, does not care for crop characteristics. Similarly, Unsatchem has its own limitations. Such models need to e modified and specified according to our own soil and environmental conditions.
It will also be relevant to pen down that even in Pakistan some electromagnetic instruments for water quality and water level measurements have been imported. Such devices are simply placed on soil surface to determine bulk water quality and water level depth without drilling into the soil. Still more advanced form is remote sensing. A number of miles can be covered in few minutes by an airplane with remote sensing and both water quality and water table depth mapped at the same time as it flies over the land. Therefore, groundwater monitoring projects may also be reviewed in light of new horizons emerging out with the time. The remote sensing results on water quality may be calibrated with field tests for their reliability.
It is relevant to state that research links between different working groups/organizations are too weak to share any thing for constructive criticism and potential improvements. The consultants mostly keep reports within their sphere for some unknown reasons. They claim so many reports and publications but only at the time when the project is no more with them. Some body must be held responsible for the circulation of such reports to the relevant agencies or organizations. Reports must code a massage for farmers. Research reports should have a wide circulation so as to strengthen the link between researchers and the farmers. Provisions in budget should be made for sharing the information framework. No institution is abreast of what the other is doing. Networking of existing institution is therefore very important to benefit the clients. The useful data must be easily accessible to the clients for their beneficial use.
The critical view of the groundwater monitoring studies conducted in the past indicate that water measurements were confined mainly to pre and post-mon seasons. The concept may be related to the percolation of rainwater into the soil that affects water level and its quality. This concept must now change and sampling be extended to other parts of the year. It is not only the rainwater to affect the water table depth but continuous practice of over extraction of groundwater by private tube-wells may lower down the water table level. So not only the rain flows but farmers’ groundwater extraction patterns may also affect both groundwater quality and water table depth. Need therefore is felt for regular monitoring of the groundwater.
Another neglected aspect of groundwater monitoring relates to the diagnosis and identification of the active zones, recharging the groundwater of a particular region. Such active recharge zones should be identified and mapped for artificial recharge. So far no exercise has been taken at provincial level. It must be included as an important element of groundwater monitoring strategies. Ponds may be excavated in the irrigation basin for artificial recharge of the groundwater. The experts report the greatest recharge contribution (30-40% of supplies) coming from irrigation system, which makes a figure of about 17-19 MAF in Punjab. The rainfall does not contribute more than 5 MAF from the last three decades. Rainfall and snow melt is responsible to charge the dams and reservoirs and it is the dams and reservoirs driven irrigation system that further recharge the groundwater. It is also added that about more than 24% (about 7 MAF) of the pumped water again returns to recharge the subsoil water. Need therefore is felt to identify the potential recharge areas and manage the recharge contributing components of the system. Electromagnetic and remote sensing (RS) technologies may assist the researcher in tracing the links between the recharging point and the locate undergoing charge. Check dams may also help recharge the groundwater systems. Similarly, injection wells, excavation of new flood canals, judicious rainwater harvesting and increased canal water supplies in the regions under severe groundwater mining may protect rapidly depleting groundwater aquifers.
The critical areas where industrial effluents have polluted the subsoil water also need to be identified and included in groundwater monitoring studies. The heavy metals contamination of groundwater not only affects soil and crops but also yields to some health implications. So this aspect of groundwater contamination must be given due emphasize in the future studies. Pollution of the groundwater through sewage, industrial effluents and agricultural residues should also be included in the groundwater monitoring project studies. While sanctioning industry the authorities should ensure installation of treatment plants to treat the effluents expected to come out. It may be ensured that primary treatment in case of sewerage effluents may be satisfactory but industrial effluents at least require secondary or tertiary treatment. Groundwater monitoring coupled with soil water and crop sampling in drain polluted regions may help to arrive at the conclusions related to its use. Sampling of live stock and blood of people who are the consumers of crops raised on soils, undergoing pollution from contaminated drainage effluents may help us to protect human life. So, comprehensive approach in groundwater monitoring studies is must.
Another thing noted is the variation in qualitative and quantitative assessment of the issues like, up stream-downstream, green water-blue water, surface water-groundwater, and water quantity-quality. This wide variation is due to the different assumptions made by different workers. Everyone modifies such assumptions to harp his own tune. Such assumptions must be clearly elaborated, while reporting the groundwater monitoring projects so that the client may not get confused. Most of the projects do not consider farmers’ participation. It is believed the end results shall suffice for them. The dissemination of information is must and it is itself taken care of where farmers’ participation to such projects is ensured. It is better to do what the farmer says rather than what we think should be done for him. Now when we are getting rid of SCARP tube-wells through its transitioning under PPGDP project we have involved farmers to participate but when we planned Scarp we did not consider farmers’ participation as important. The participation of the farmers should not be neglected at all stages of planning and operation of groundwater monitoring projects. The above discussion reveals that groundwater monitoring for sustainable groundwater resource management is not one profession-job. It requires integrated approach and knowledge skills of soil scientists, agronomists, agricultural engineers, hydrologists, crop scientists, laboratory analysts, GIS / remote sensing scientists and still many others. It necessitates the event of networking of existing institutions and that of individuals in their personal capacity. Only a comprehensive and integrated approach may help us find out some potential solution to our both groundwater and management related problems. The irrigation managers are suggested to please ensure a viable groundwater monitoring and management plan so as to really benefit water users in the best interest of the country.
