This survey has described the foreseeable environmental and economic impacts of enhanced oil-recovery (EOR) on U.S. oil production between 1980 and 2000. It has indicated that EOR production may be expected to rise from the approximately 4% of total U.S. oil production in 1980, to the projected approximations of 10.5% in 1985, 18.5% in 1990, 23% in 1995, and perhaps 30% in 2000. These percentages are substantial, particularly as this form of oil production has been, up until recently, quite limited. Many of the processes are still in the laboratory stage of development—particularly chemical and microbiological processes. With continued laboratory experimentation and field research, it is possible that the percentages could be even greater than the above suggestions as we reach into the 21st Century.

The potential for EOR is very considerable and probably great, as it could involve some two-thirds of all the oil already identified in the United States and assumed to be unrecoverable by primary or secondary means. The U.S. Department of Energy (DOE) has given important incentives to the EOR industry to make such increased production worth while through raising prices to compensate for the cost of equipment, and deducting expenditure on such equipment from a new ‘Windfall Profit Tax’.

Along with EOR's economic potential, there are two major ecological dangers: air pollution through thermal processes, and ground-water pollution through chemical processes. It is essential to the well-being of the United States that clean air standards be adhered to, and that the equipment necessary to purify the air (particularly in California) be available and operate to reduce emissions.

A great deal more research needs to be undertaken towards developing safeguards to ensure that drinkingwater is not contaminated by dangerous chemicals which may be used in ‘chemical flooding’ of depleted oil-wells. Many of these chemicals have merely ‘come out of the laboratory’ and are sold by chemical companies without sufficient field-testing. How far these chemicals could travel underground must still be determined. It is also important to ensure that carbon dioxide, fed into a geological formation, can be recaptured and re-injected without escaping into the atmosphere, where there is the potential danger of a global ‘greenhouse effect’ upon the world's temperature. Finally, it is important to safeguard the Earth against microbes which could be injected into its geological strata without sufficient knowledge of their impact on the ecology of the Earth. Thus, much environmental research will be called for with these new methods of producing oil for Man's use.

This study has reviewed the four major methods of EOR that are currently being utilized or proposed— thermal processes, miscible and semi-miscible processes, chemical processes, and microbiological processes, and found that they could all have ongoing possibilities.

Given appropriate environmental safeguards, EOR should become a major force in the production of energy for the United States over the next 20 years, and it seems reasonable to expect that much the same could apply to other parts of the world. However, it is important that safeguarding the environment should guide the DOE in terms of its incentive programmes for specific processes.

Successive inquiries into the problems associated with population, growth, resources, and environment, have stressed the need for new environmental management policies and techniques. Environmental impact assessment, whose evolution is briefly described in this paper, will be a vital ingredient in any transition to an environmentally sustainable world order.

There is a substantial and growing literature on the use of environmental impact assessment methods, although relatively little has been written on the increasing use of such methods by industry in some countries— often without any direct compulsion by Government. A range of examples of the industrial use of environmental impact assessment are reviewed, and the conclusion is drawn that properly designed methods can help industry to meet its own basic objectives of survival, profit, and growth.

While there are considerable problems associated with the prediction of ecological and other environmental effects, particularly where the baseline data are inadequate or non-existent, the experience of a growing number of companies and other industrial organizations does suggest that environmental impact assessment is increasingly recognized as an indispensable management tool in those industries which are likely to meet environmental resistance in their development planning operations.

There is much to be learned if we are to optimize the procedures for maintaining ice-free roads in the wintertime. Sociological studies indicate that investigations should not only be of technological measures to maintain bare pavements for ‘summer driving’ in the winter, but also we might well reduce the driver's expectations, educate him or her in the matter of how to drive under hazardous conditions, and generally accept a lower level of mobility in exchange for reduced costs and environmental damage.

Increased availability and efficiency of public means of transit may be forced upon an unwilling public in the years to come by a much-reduced portable energy-source (gasoline), and this change in transportation habit may have further impact on winter maintenance procedures. For many reasons, we can no longer use the methods of the past with a gay disregard for our environment and often limited resources faced by an increased world population.

The paper deals mainly with the use particularly of common salt (NaC1), but also of calcium chloride (CaCl2) and the defroster Verglimit, to reduce hazards on roads in times of freezing temperatures, and concludes that, whereas the former single chemicals pose environmental problems as possible ground-water and surface-water hazards to humans and their corrodible possessions, as well as to vegetation especially near treated highways, the multi-chemical patented Verglimit offers an encouraging new approach—apart from its high cost which, however, can be mitigated to some extent by judiciously limited application.

Between late 1978 and mid-1979, two major coastal vegetation plantings were completed on dredge material in Tampa Bay, Florida. On the dredge material extension of Sunken Island, 1.64 ha of Smooth Cordgrass was planted via 12-cm ‘plugs’ on 1-m centres, in rows 2 m apart. After 14 months, this planting is showing 93.4% survival. On dredge-material island CDA-D, 0.52 ha of mangroves (63% Black and 37% White) was planted via 0.3–1.9 m transplants on 2-m centres. After 13 months, this planting is showing 73.3% survival.

The nature of these two plantings permits a comparison of their cost and man-power requirements. The labour requirements for Smooth Cordgrass were 995 man-hours/ha as opposed to 2,541 man-hours for mangrove transplanting. Smooth Cordgrass requires $4,566/ ha for plugs ($1.03/plug) while mangrove transplants cost $11,459/ha ($3.92/transplant). These costs are for comparison only, as they entail primarily labour and neglect most of the indirect costs that may be experienced.

An analysis of benefits for both salt-marsh and mangrove planting indicates that Smooth Cordgrass provides greater primary production on a g C/m2 basis than mangroves. Both plantings serve as colonial waterbird nesting habitat and source-areas for further planting, but Cordgrass does so in a shorter time-frame. When weighing the positive and negative aspects of both, Spartina alterniflora is preferred over mangroves where both are present.

Collisions between birds and aircraft have caused damage to, or destruction of, aircraft and loss of human life for more than 68 years. Birds are attracted to airfields by the large open spaces which they provide and, often, by the availability of food, water, and shelter, on or near the airfield. Birds attracted by open space can be driven away by trained persons furnished with suitable bird-dispersal equipment, while removal of food, water, and shelter, can reduce the attraction.

Mass movements (migrations) by birds, especially large birds, create hazards for aircraft aloft. Air traffic control radar can show the abundance, speed, and direction of movement, of birds, while correlation of those movements with weather parameters permits development of bird movement hazard forecasts. Although the periods of high hazard are of short duration, use of these forecasts to make changes in flying training programmes has reduced losses of Canadian military aircraft through bird studies.

Automatic digital presentation of bird movement data gathered by radar has been tested at two airfields by air traffic controllers for possible use in vectoring scheduled civil aircraft away from hazardous concentrations of bird migrants. A decision on operational use of the technique has not yet been made.

Reduction of bird hazards to aircraft depends upon human motivation. The necessary habitat control, bird dispersal, and migration hazard forecasting, involve timeconsuming, rather dull work that is repeated at prescribed intervals. Unless the work is always well done, bird-strikes on aircraft will continue and human lives and aircraft will be lost.