DISCUSSION ON FUTURE DIRECTIONS
About five years back, The Natural Resources Management Center (NRMC) of the Department of Agriculture has held a symposium on “Groundwater utilization for crop production in the dry zone of Sri Lanka” to disseminate the findings of the “Groundwater utilization for crop production project” which was funded by the FAO (UN) and coordinated by the NRMC, Peradeniya. The symposium has arrived at certain recommendations on “Policy guidelines for groundwater use” and “Technical guidelines for groundwater extraction and groundwater utilization for irrigation”.
The guidelines as listed in the proceedings of the above symposium are reproduced below so that it can be used as the starting point for today’s discussion on future directions.
1. It is recognized that groundwater exists in the hard rock areas of dry and intermediate zones. It is also observed that agro-wells and tanks are hydrologically connected and exists in a cascade system. Tank cascade has to be used as a unit of analysis for planning purposes. As there is a limited amount of available groundwater, there is a limit to the number of agro-wells that can be successfully operated. There is also a delicate balance between the two, which should be preserved. Therefore, agro-wells should be used conjunctively with rainfall and tank water.
2. At present agro-wells are constructed without any concern for the environment. For sustainable groundwater use for irrigation "carrying capacity" of wells (or extraction value) for each cascade system need to be determined and the number of wells should be maintained within the limit.
3. Further research on groundwater availability and development of groundwater for conjunctive use on a pilot scale needs to be carried out.
4. Awareness among all the groups involved (political, general public, government and non-governmental officers, and farmers) on the potential dangers of overexploitation of groundwater should be created.
5. It is very clear that the present legislation is not sufficient to guide people to use groundwater in a sustainable manner.
6. There is a lack of coordination among the organizations that promote construction of agro-wells. Various agencies provide support for indiscriminate construction of agro-wells. This approach is self-defeating and destructive. There is a necessity for having a central agency to coordinate all activities related to groundwater use.
7. There is an urgent need to review and revise existing policies, legislation and enforcement concerning agro-well construction and management. The issue is considered serious enough to be taken at the highest political level.
8. There must be a policy to ensure the efficient use of all agro-wells in the country.
Guidelines for groundwater extraction
1. The basic land unit that is to be used for analysis and development of groundwater in the dry zone has to be a cascade micro-watershed.
2. Rainfall, land use, geology, water outflow from the watershed (surface and subsurface), groundwater levels, water abstraction rates, water use by different land users and influence of water abstraction from deep wells on the shallow wells have to be further studied. Data on the influence of irrigation canals on the water table are also needed for proper assessment of groundwater availability.
3. Environmental impact of agro-well irrigation has to be studied and short-term as well as long-term follow-up actions are needed. In view of the seriousness of damage caused to environment due to over-exploitation of groundwater, immediate steps should be taken to contain the problem by making appropriate recommendations based on the existing information, to limit extraction. These recommendations could be fine-tuned once the gaps in information are filled with further studies. Such recommendations should include guidelines for policymakers, politicians, regulators/institutions, technical and professional staff, and agro-well farmers.
4. In order to prepare guidelines based on existing information on water extraction, it is recommended to setup a national task force. This task force should identify critical areas/regions of groundwater and propose institutional arrangement to implement the guidelines.
5. Following long-term follow-up actions are recommended:
Development of project proposals and securing of funds for further research. Prioritization of research related to agro-well irrigation by relevant institutions. Continuous monitoring of groundwater level and maintenance of a groundwater inventory.
6. The available information on groundwater availability and extraction related to agro-well irrigation need to be disseminated to groundwater users, potential users, funding organizations, policymakers, planners, and various donors and project personnel. Mass media publications and awareness creation programs are possible means of achieving this end.
Guidelines for groundwater use for irrigation
1. Before construction of an agro-well, assessment of water quality and the quantity that can be extracted need to be assessed. Important quality assessments are pH, Electrical Conductivity (EC) and Sodium Adsorption Ratio (SAR).
2. Selection of lands to construct wells for irrigation and development of selected lands to facilitate efficient irrigation must be done very carefully. In the land development process drainage (surface and subsurface) aspect also need to be considered.
3. Cropping system should be accompanied with better crop selection, land preparation and efficient method of water application in order to increase the water use efficiency and farmers’ income. As the water availability is very much limited, moisture conservation methods have to be applied wherever possible. Efficient irrigation systems such as drip irrigation could be promoted for high value crops.
4. Dissemination of information is very important. Hence, it is recommended to take greater extension effort on dissemination of relevant information on crop selection, cropping system, land preparation and efficient methods of water application.
5. Agro-wells should be always used to supplement rainfall and other sources of surface water. Planning of cropping calendar should be done accordingly with active farmer participation.