A procedure for environmental impact assessments (EIA) for seawater desalination plants

The proposed EIA procedure follows a minimal guideline which consists of 1) analysis of the source of impacts, 2) analysis of the impacted ecosystem, 3) definition of the links between source and targets, 4) recommendation of mitigation measures and 5) sustainability of the environmental protection measures. For step 1, the focus is on the components of the discharges into the sea where ten groups of environmentally critical substance groups are discussed. For step 2, it is pointed to an earlier subdivision of the corresponding marine ecosystem into subsystems, which are ordered according to sensitivity. Steps 3, 4, and 5 are outlined as far as it is feasible for a general treatise, which is independent of a distinct plant or region. The final claim is for the persecution and publication of serious EIA’s to provide methodical and exemplary cases.

Environmental impact assessments of desalination plants are necessary and possible. They are necessary, because desalination plants share the properties of other large thermal industries such as power stations and exceed those regarding emissions into the water. They are possible, because experiences and tools are available or can be elaborated as it has been done for other objects. To demonstrate this is the main purpose of this report. This article mentions, but does not treat, aspects such as socio-economy, coastal zone management and site specific recommendations. The term socio-economy is emphasised particularly to avoid the misunderstanding that it is of less importance in the opinion of the author. The socio-economical importance has been highlighted so often and so convincingly (e.g. [34]) that it has not been repeated here. Socio-economic aspects are genuine parts of environmental impact assessments. The decisions, how, where, and when to build what desalination plant, finally are compromises of environmental and socio-economic arguments. I pointed to the large number and power of the desalination plants along the shoreline of the Arabian Gulf. I regret that in spite of the common location within a semi-enclosed sea, desalination activities are far away of forming a co-ordinated system. The result is the problem of mutual impacts and of a capacity limit of the Gulf as a whole. The Gulf Co-operation Council (GCC) does not seem to be a suitable platform of the necessary co-ordination. The establishment of the Middle East Desalination Research Center (Muscat) therefore is highly welcome. A term widely used but not mentioned so far in this article is sustainability. Planning and realisation of a seawater desalination project should be sustainable in so far, as – long-term operation is possible without increasing ecological damages and – enlargement of the plant is possible without exceeding those limits of environmental compatibility which at the first agreement to the construction were made condition to be kept in the future. The enlargement of a given plant should not only be in view because population, industry and agriculture may grow, but also because climatic changes are probable which lead to a higher water demand [29]. Localisation, construction and operation of a given plant should be sustainable in so far, as probable effects of the expected sea level rise – do not endanger a desalination plant so that environmentally adverse measures are to be taken and as – effects of the plant do not enhance consequences of the sea level rise. We give an example for the latter recommendation: Along a tidal coast, it is open whether the level of the sediment surfaces will be able to rise with the sea level rise, and it is open, which sediment sources will provide the necessary sediment amounts. A minimum demand is that the sediment dynamics is not disturbed as it may be the case by unadapted construction of intakes, outlets, and break-waters which are typical for coastal desalination plants. Those buildings may hamper the sediment transports and may enhance the sediment budget problems.