Geomorphology and Environmental Impact StatementsAuthor(s): John LewinSource: Area, Vol. 7, No. 2 (1975), pp. 127-129Published by: The Royal Geographical Society (with the Institute of British Geographers)Stable URL: http://www.jstor.org/stable/20000985 .

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Geomorphology and environmental impact statements John Lewin, University College of Wales, Aberystwyth

Summary. Experience in the composition of environmental impact statements suggests that geomorphology could benefit from closer attention to training in relevant mapping

procedures, from greater study of the functional aspects of landforms, and from the development of methods whereby activity rates can be more rapidly inferred.

Since the Environmental Policy Act came into operation in the United States in 1969, it has been necessary to make an environmental impact statement con cerning major developments on public land so that environmental values are taken into account as well as economic and technical considerations. There now exists a profusion of studies undertaken for this purpose, ranging from major

multiple-volume ones such as that on the Alaska pipeline, to assessments of the impact of alternative alignments of a few miles of interstate highway. For a variety of reasons, the reports themselves are likely to have a less than crucial impact on development tactics; this is partly because other considerations are overriding, but partly because many reports are confused and wordily indigest ible. Some attempts at standardization have been made (Leopold et al., 1971),

but difficulties also arise because the task of providing clear evidence for the compositions of these statements can lie beyond the generally available competence of contemporary field science. This is specifically true of geomorphology. Following recent experience in assessing geomorphology and environmental impact in connection with the development of oil shales in western Colorado, the following considerations are put forward for discussion. Environmental impact work of this kind, although not within the same legal and perceptual framework, is equally relevant in a European context, and the energy and funds devoted to such work are just as likely to lead to striking scientific developments in geomorphology as did the early explorations of the American west a hundred years ago.

The task commonly set is this. Following at most one or two field seasons, a geomorphologist may have to present some kind of assessment of the geo morphological environment, and to predict what the results of placing some sort of plant, mining operation, road, or whatever, in one part of this may be.

An initial phase may thus be a mapping exercise in which landform units are distinguished. Wide availability of remote sensing imagery makes this task easier, as does the availability of a number of systems of landform mapping (for example, Mitchell, 1973). Unfortunately, pre-existing mappings usually turn out to be inappropriate, nor does it seem likely that the information contained in some pre-ordained data bank, if it existed, would prove wholly satisfactory. One problem is that the scale at which information is required is large so that both alternative situations or routes, and alternative sites perhaps less than 20 m apart, can be evaluated. For instance, in the Colorado study it appeared necessary to map talus with some precision so that even the toe of such deposits could be avoided in road alignment because of the instability problems likely to arise. A functional subdivision of slopes is thus particularly useful

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128 Geomorphology and environmental impact statements

(Dalrymple, Blong, and Conacher, 1968) as is the geotechnical approach normally used by some geologists and engineers in Britain (see, for example, Engineering Geology vol. 6, 1973). The lessons to be learnt could be that, in so far as they are

mutually exclusive, support for a flexible training in field survey techniques is more worthwhile than enthusiasm on behalf of some nation-wide survey scheme or data bank which in the event provides the wrong information at the

wrong scale. A functional approach is additionally desirable in that environmental impact

is often inconveniently interdisciplinary: for instance, a modification in slope form may lead to vegetation change and habitat alteration. Close collaboration and teamwork amongst environmental scientists is advisable, as is meaningful integration of their mapping systems. Training in physical geography would seem to favour such an integrated approach, but there does seem to be insufficient enthusiasm on the part of geomorphologists still to study how land forms function, as well as how they form in the longer term. Information about the former is very useful, even when the known history of landforming pro cesses makes such information only marginally relevant to the latter.

Having mapped geomorphology in some more or less satisfactory manner, there remains the task of defining the impact of specific implantations. We here come up against the greatest difficulty, since activity rate of natural processes are normally unknown. Knowledge of the dynamics of the system concerned is certainly necessary, as perhaps a biological analogy may make clear. It may be known that a certain percentage area of a certain plant community will be destroyed: will this be a large enough proportion seriously to interfere with natural regeneration of the community as a whole? If sediment of a certain volume and size range is to constitute a new stream bank, will the prevailing rates of channel migration and stream power remove the materials or be constrained by them? We know so little about process rates, and the year or two available for impact study is not long enough for this knowledge to be gained by

most conventional techniques as in the direct observation of material move ment on slopes, solute and sediment dynamics, or channel migration. A possible alternative is to exploit to the full indirect methods for the estimation of process rates: historic maps and air photographs for channel change, root exposure for slope erosion, radiometric dating of recent slope and valley bottom deposits, and so on.

Thus the stimulus of impact statement composition appears to require three things of the geomorphologist: firstly an increasing concern for purposive

mapping procedures at what might be called the geotechnical scale; secondly, closer attention to the way landforms are functionally interrelated with other aspects of the environment; and thirdly the development of methods whereby activity rates can be rather rapidly inferred. It may then be possible to evaluate not simply the immediate site impact of structures, about which engineering expertise may be generously available, but also their more widespread and longer-term role in environmental activity. This is important, for such impact

may be widespread, and prolonged for a very long time indeed (Davies and Lewin, 1974).

References

Dalrymple, J. B., Blong, R. J. and Conacher, A. J. (1968) 'A hypothetical nine unit land surface model ', Zeit. far geomorph. 12, 60-76

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Geomorphology and environmental impact statements 129

Davies, B. E. and Lewin, J. (1974) ' Chronosequences in alluvial soils with special reference to historic lead pollution in Cardiganshire, Wales', Environmental Pollution 6, 49-57

Leopold, L. B. et al. (1971) 'A procedure for evaluating environmental impact', U.S. Geol. Survey circular 645

Mitchell, C. W. (1973) Terrain evaluation

Editor's postscript. The Department of the Environment announced on 9 December 1974 that Mr Geoffrey Thirlwall and Mr J. Catlow had been appointed by the Secretaries of State for the Environment and for Scotland and Wales to undertake a study into the ways of measur ing and analysing the environmental impact of development proposals. Their terms of refer ence required a consideration of the circumstances in which development proposals would give rise to the need for environmental analysis; to survey the techniques now being used or devel oped to measure environmental impact; and, among others, to make recommendations for further research.

Comments and replies to a list of questions would be welcomed from 'interested bodies' outside local government. A copy of the memorandum containing the questions sent to local authority associations and other bodies can be obtained from the group's secretary, Miss A. Batty, Room P2/120, Department of the Environment, 2 Marsham Street, London SWIP 3EB.

IBG Study Group reports for 1974*

Biogeography Study Group

The Group, with a membership now in excess of 100, held two meetings during the year, a Field Symposium at Gregynog Hall in central Wales in September 1974, and a one-day symposium on the subject of ' The impact of man on the palaeo-environment ' at the IBG Oxford conference in January 1975. The former focused on the measur

ment and management of upland habitats and included a field excursion which studied the ongoing research investigations taking place in the Plynlimon area (including those of the Institute of Hydrology, the University College of Wales, Aberystwyth, the Welsh Plant Breeding Station, the Ministry of Agriculture and the Forestry Commission) and a day of paper-reading and discussions on methodological, technical and interpre tational problems in ecological and associated research fields in central Wales and in analagous areas. Attendance totalled 25 and the success of the Symposium (organized by J. A. Taylor) was ensured by active participation of all present in vigorous, inter disciplinary debate and by the excellent setting and services generously provided by Gregynog Hall and the University College of Wales.

The Oxford Symposium attracted twelve papers on palaeo-environmental research which ranged in site-reference from the Orkneys to Exmoor and from Northern Ireland to Dorset. Two papers cited work in Finland, Sweden and New Guinea. In addition to basic pollen analysis, relevant archaeological and historical evidence was assessed and integrated. The regional significance of palaeo-environments and their selective local modification by man is clearly beginning to emerge as is the inestimable value of interdisciplinary approaches in this kind of research. The meeting was conspicuously successful due in large measure to the perceptive nature of the papers and discussions and the assiduity of the organizers, Dr I. G. Simmons (Durham) and Dr I. M. Fenwick (Reading).

*A complete list of the officers and committee members of study groups for 1975 appears on the inside back cover of Area 7 (1975), 1.

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