GROUNDWATER PROTECTION*)

An effort to maintain sustainable development and environmentally sound management of groundwater resources in Indonesia

by : Soetrisno S.

Abstract

 

Abstraction of groundwater resources for various purposes in many major cities in Indonesia has led to the degradation of both quantity and quality of those resources and its environment. Nowadays groundwater resources in Indonesia become an economic commodity and have a vital role in our development.

Realizing its vital role, in order to maintain sustainable development and to comply with Chapter 18 'Protection of the Quality and Supply of Fresh Water Resources' of Agenda 21, groundwater protection in Indonesia is indispensable.

Hydrogeological knowledge of the groundwater regime and legal aspects are two things required to set-up groundwater protection areas. However, since groundwater resources are only a single facet in the hydrologic cycle, the effectiveness of groundwater protection also depends on many aspects which are involved in the hydrologic cycle.

Groundwater protection areas addressed to spatial planning of a certain area, can only be achieved through an integrated effort embracing local, regional and even national planning.

The suitability of groundwater resources from various purposes, on long term basis, can be sustained only if adequate measures protection of groundwater are conducted.

The difficulties to rehabilitate polluted a groundwater system and its quantity should encourage all parties to understand the vital need of groundwater protection in order to maintain our groundwater resources.

 

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*) Paper presented at 'Expert Group Meeting Preparatory to the First Session of the Committee on Environment and Sustainable Development", Bangkok, 30th September - 2nd October 1993.

1. Introduction

Groundwater resources have contributed substantially to the clean water supply in Indonesia. Groundwater has been utilized for many centuries, particularly shallow groundwater for domestic purposes. Deep groundwater had begun to be developed since the middle of the 19th century, when a deep well was successfully drilled in 1848 at Fort Prins Hendrik, a fortress in Batavia (presently Jakarta). Since then deep wells have become the means of providing water for many purposes in other parts of Indonesia. At present, groundwater is a major source of water for urban, rural, industrial needs, and in agricultural areas for irrigation.

In the development of the country, the rate of groundwater exploitation has increased enormously. Population growth, increase in the quality of life, and industrial development have led to the rapid increase of groundwater exploitation from private wells in urban areas. For example in 1970 Jakarta consumed less than 10 million m3/year of deep groundwater, which tripled in 1987.

At present about 70 % of the total clean water supply rely on groundwater, whereas industry relies nearly 100 % of its water need on groundwater resources.

On the other hand, increasing groundwater exploitation has already caused negative impacts on the resources itself, both in quality as well as quantity and to the adjacent environment. In coastal areas such as Medan, Jakarta, Semarang, Ujungpandang, and Denpasar, sea water encroachment has led to the deterioration of the groundwater quality, while land subsidence phenomena are recorded in the Jakarta basin. The changing environment as a consequence of rural development has also brought undesirable effects such as deterioration of the groundwater quality.

Realizing the role of groundwater in supporting national development, firm efforts should be taken to conserve this natural resources.

The lowering of the water level both of the shallow and deep groundwater system in Indonesia due to groundwater exploitation is the direct impact, which can be easily observed through observation wells in many groundwater basins. In the nineteen sixties, the static water level of the deep groundwater in many groundwater basins was generally near or above the surface. At present, the above condition has changed, and the water level has dropped far below the ground surface.

The general condition of the water level in 1990 as recorded from several observation wells in areas where groundwater has already been exploited intensively, showed that the groundwater level lies between 20 - 40 m below the surface. Observations in the last ten years showed that the deep groundwater level declined 1 - 3 m/year in most parts of the groundwater basins, such as in Jakarta, Bandung and Semarang. This condition has considerably changed the recharge and discharge situation in many groundwater basins during the natural stage, when discharge quantities did not yet exceed recharge quantities. Recharge from rainfall infiltration replenished the shallow aquifer during the rainy season. When upward leakage from the deeper aquifer system could enter the shallow system.

The actual situation which developed due to overexploitation of the deep groundwater system would be that discharge quantities frequently mostly exceed recharge quantities, resulting in the decline of the groundwater level. The deep groundwater level (piezometric head level) is generally below the phreatic head (shallow groundwater level) of groundwater. Consequently recharge to the deep aquifer system happens also by vertical downward leakage.

The implication of the above situation is that the deep aquifer system is at high risk to pollution from the above system, while the decline of the water level due to overexploitation will change the hydraulic gradient, thus triggering the speedy movement of the pollutants from above to the deeper groundwater system. In coastal areas, such condition has led salt water intrusion into the fresh groundwater system. Land subsidence phenomena are recorded in Jakarta, with rate of subsidence in the range of 23 to 246 mm/year. Over exploitation of groundwater apparently is the major cause of this subsidence.

Contamination of shallow groundwater by domestic waste has been recorded mostly in urban areas, as a result of poor drainage and sewerage. The high content of chlorides of over 500 mg/l and the presence of nitrites indicate that groundwater has been contaminated.

High population density in most of the urban areas, the limited extent of a central sewerage system and inadequate treatment facilities for sewerage water, form a high risk in groundwater contamination due to infiltrating domestic waste water particularly to the shallow system.

In some urban areas, where domestic waste dumping sites are not located in proper places, shallow groundwater has been contaminated.

Groundwater contamination derived from industrial waste mostly affect the shallow aquifer. Most of the industries have no effective treatment plant for their waste, they simply discharge their waste to the surface water bodies, leading to the contamination of the shallow groundwater.

Intensification of agriculture especially in the rice field influence the groundwater quality in particular by excessive fertilizer use and of pesticide residues transported into groundwater. High evapotranspiration from irrigated water may result in increasing salinity of the infiltrating return flow and subsequently to the groundwater.

2. Efforts

On the basis of legal and technical aspects which has to be taken based upon the hydrogeological knowledge of a respective area, efforts have been made to protect groundwater resources, both in quantity and quality, which are as follows:

1. To restrict the extraction of deep groundwater.

   Restricted of licenses for industrial use is issued based upon the binding technical recommendation given by the Directorate of Environmental Geology, in order to restore water level.

2. Adjustment of groundwater strata extraction.

   In areas where the hydrogeological condition permits, extraction from the deeper aquifers has to be conducted.

3. To undertake artificial recharge into aquifers.

   During rainy season water can be collected from the roofs and infiltrated into wells in order to increase the recharge into the shallow aquifers. However, infiltration wells can be built only in areas where the hydrogeological condition is favourable.

4. To work out a plan and regulation for extraction of deep groundwater.

   Based on the result of investigations in the past years, a mathematical model for several groundwater basins has been established. This model gives scenarios, with annual schemes of rational extraction of deep groundwater, putting forth the optimum allocation plan for extraction at certain periods for different areas and different layers of aquifers.

5. To set-up groundwater protection areas.

   Groundwater protection areas addressed to spatial planning of a certain area in order to protect both the quantity and quality of groundwater resources. To determine groundwater protection areas, beside hydrogeological condition, actual land use and existing infrastructure have to be considered.

In this respect environmental geology has a deterministic role, since it provides or is able to obtain key information on the main factors. These include the occurrence and size of economic deposits, soil types, building or construction materials and above all, the availability of groundwater and the conditions for its protection. It is therefore necessary to compile environmental geological data in order to make it available for planners.

In view to the dense population and requirements for intensive land use in urban areas in Indonesia, it appears impossible to apply protection measures for all occurrences of explorable groundwater. On the other hand, no regulations are available to specifically govern the groundwater protection areas as mentioned before. Law No. 24 of 1992 and Presidential Decree No. 32 of 1990 give only guidance to manage protection areas in general. However, recommendable measures for groundwater quality protection in the urban areas have been set-up.

The requirements of groundwater protection in regional planning and land use developments in the urban areas can be formulated (Wagner & Sukrisno, 1991).

• New residential and commercial areas are to be build outside groundwater protection areas, except adequate sewerage system has been installed and piped water supply is advisable.

• New or expansion of industrial areas should not occur within groundwater protection areas, except adequate waste water collection and treatment systems have been installed, preferably not in areas with restricted groundwater abstraction.

• Waste disposal sites are not to be built in groundwater protection areas.

• Traffic (roads, railways, airport) and exploitation of mineral resources in protection areas should be constructed only after detailed investigations.

• Deep excavations in protection areas are to be restricted or accompanied by protective measures.

• Conservation of present land use; preferably all presently forested areas and in protection areas with presently prevailing agricultural land use.

All the above steps have to be backed-up by government policy on industry. Industries which are consuming a lot of water and produce pollutant waste must be put on negative list for investment.

3. The Constraints

The implementation of groundwater protection measures, however, face several constraints, apart from dense population and competitive land use as already described before.

There are four constraints such as :

1. Administrative : in several cases the coordination among sectors related to groundwater has to be enhanced. There is no regulation which particularly sets up the requirement of groundwater protection areas.

2. Technical : not enough detailed hydrogeological information, which will lead to determine groundwater protection areas.

3. Economical : high cost economy required to serve population other than groundwater resources.

4. Social : unawareness of various groundwater users of the neccesity to conserve groundwater resources.

As groundwater resources are only one part of the components of the hydrologic cycle, as mentioned above, to overcome the above constraints, therefore, all efforts concerning groundwater protection have to be taken integrally. The other important thing is that government policy has to set-up highest priority for new industries which consume low ammounts of water and clean industry.

4. Conclusion

The suitability of groundwater resources for various purposes in Indonesia, on longterm basis, can be sustained only if adequate measures for protection of the groundwater are taken.

Groundwater protection has to be carried out in an integral way and backed-up by favourable policy on low water consumtion and clean industries.

The difficulties and high cost of restoring the groundwater level, treating dirty water and the impossibility, even in the medium term, to rehabilitate a polluted groundwater system should induce all parties to recognize the vital need of groundwater protection aimed at maintaining our groundwater resources in order to support sustainable developments.

References

Djaeni A., 1973, The Quality of Groundwater in Indonesia, Directorate of Environmental Geology, Bandung.

Hahn J., 1991, Balancing the Requirements of Land Use and Groundwater Protection in Rural Areas, International Hydrological Programme IHP III Project 10.6, Unesco, Paris.

Haryadi, Djaendi, dan Harnandi D., 1988, Survei Penyusupan Air Asin di Wilayah Jabotabek (DKI), Direktorat Geologi Tata Lingkungan, Bandung.

Hehanussa, P.E., 1979, Salt Water Encroachment into the Jakarta Artesian Basin, PIT-VII IAGI, Bandung.

Ploethner, D., 1982, Groundwater Investigations in the Cianjur Area, Kabupaten Cianjur, West Java, Directorate of Environmental Geology, Bandung - Federal Institute of Geosciences and Natural Resources, Hannover.

Soefner B., Hobler M., and Schmidt G., 1986, Jakarta Groundwater Study 1983 - 1985, Final Report, Directorate of Environmental Geology, Bandung - Federal Institute of Geosciences and Natural Resources, Hannover.

Soekardi P., 1986, Legislation and Institutional Arrangement of Groundwater Development in Indonesia, Directorate of Environmental Geology, Bandung.

Wagner W., Ruchijat S. and Rosadi D., 1991, Groundwater Resources and Groundwater Protection in the Bandung Basin, Project Report No. 15 Directorate of Environmental Geology - German Environmental Geology Advisory Team for Indonesia, Bandung.

Wagner W. and Sukrisno, 1991, Groundwater Quality Protection in the Northern and Eastern Parts of the Bandung Basin, with conclusions for Land Use and Regional Planning, Directorate of Environmental Geology - German Environmental Geology Advisory Team for Indonesia, Bandung.

 

 

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