Geological fluvial geomorphology CENTENNIAL ARTICLE VICTOR R. BAKER Department of Geosciences, University of Arizona, Tucson, Arizona 85721 ABSTRACT disdain the approaches and/or problems of oth- phasis that Gilbert had placed on timeless, equi- ers. Moreover, there are fundamental dichoto- librium processes of landform genesis (Chorley The history of American fluvial geomor- mies in the basic assumptions made by individ- and Beckinsale, 1980; Ritter, 1988). phology over the past century is viewed as ual geomorphological researchers as they pursue There are parallels between the ways scien- one of conflict and crises. From 1888 to 1938, various studies. Views such as gradualism in tists organize their own programs of study and a controversy arose between (1) a rational process operation, randomness in nature, and the ways that historians may organize the anal- approach to understanding landscape genesis dynamic equilibrium in landscape development yses of such programs through time. Thus, one and history, with its roots in geology, and may be held in personal preference to contrary obvious approach to the history of American (2) a spatial-analytical approach to landscape assumptions. geological fluvial geomorphology over the past classification and description, with its roots in A century ago, geomorphology was in its century might be an evolutionary one, perhaps geography. By the 1960s, geomorphology, golden age. It was a science filled with wonder punctuated with the occasional major change in led by fluvial studies, had changed its empha- and excitement. The source of scientific stimulus scientific program. Thus, Morisawa's (1985) his- sis from historical studies to process studies, was not the establishment of new methodologies tory recognizes a progressive increase in the use and the geology/geography dispute became for landscape study. Rather, it was the discovery of quantitative approaches to problems, punctu- irrelevant. Since the 1960s, a new conflict has of new phenomena in landscapes that seemed as ated by Horton's (1945) seminal paper on arisen between (1) problem-oriented studies bizarre and alien to the residents of humid- drainage-basin analysis. Whether or not quanti- of landform genesis and (2) method-oriented temperate academia as the surfaces of other fication constituted a true scientific revolution studies. The latter emphasize useful predic- planets seem to most of today's terrestrial geo- for geomorphology, it certainly engendered a tions and a methodology that generates re- morphologists. For American geological geo- new program of effort based on quantitative spect from other scientific and engineering morphologists, the most important scientific measurements of processes, statistical treatment disciplines. In extreme cases, approach 2 may trinity was not structure, process, and stage, of data, and predictive models with practical bypass the understanding of phenomena in emerging from the heuristic synthesis of a Har- applications. As pointed out by Morisawa order to generate useful predictions of sys- vard scholar. Rather the critical trinity was Gil- (1985), much of the methodology for the new tems assumed to embody the behavior of bert, Powell, and Dutton, who were stimulated program was borrowed directly from engineer- those phenomena. In order to achieve its goal by studies of the arid western United States. ing disciplines, such as hydraulics and hydrol- of intellectually satisfying understanding of ogy, as well as from basic physics, chemistry, The American character of geological fluvial phenomena, approach 1 may require the and mathematics. Moreover, the kinds of geo- geomorphology derives directly from the scien- stimulus of the occasional outrageous hy- morphological problems studied under this new tific example of Grove Karl Gilbert and the or- pothesis, thereby posing a seeming anathema program tended to be those that were most eas- ganization of the United States Geological to an existing scientific program. The identifi- ily analyzed by the new methodology. Survey by John Wesley Powell. Considerable cation and explanation of anomalies is critical history has been written on this era of fluvial Perhaps even more substantive than mere to approach 1. Because of the inherent con- geomorphology (Chorley and Beckinsale, 1980; quantification has been the move toward a dy- flict in these approaches to fluvial geomor- Pyne, 1980; Tinkler, 1985), and so, rather than namical basis of geomorphology, inspired by phology, there is a need to balance opposing again describing its inspiration, let suffice Dut- Strahler (1952). It would be heartening to re- tendencies. ton's (1885) acknowledgment of his two col- cord the progressive march of geomorphology leagues. "If I were to attempt payment, I would toward understanding modern surficial Earth INTRODUCTION be bankrupt" (p. 198). processes in a physical-quantitative fashion. As a Probably the only great revolutionary change geological science, however, geomorphology Geomorphology is one science divided by ar- that ever occurred in geomorphology was the must strive not only to understand modern bitrary classifications that contribute nothing to one that Hubbert (1967) recognized for all geol- Earth processes, but to place this understanding the understanding of landscapes but much to the ogy and which he termed "Huttonian-Lyellian- within the broader context of Earth history. As impediment of such understanding. Fluvial Darwinian." The Darwinian influence was stated by Bryan (1950): "the essence of geomor- geomorphologists are divided into geographers paramount by the early 1900s, when Russell phology is the discrimination of the ancient from and geologists by arbitrary academic convention, (1904) described geomorphology as a science the modern." Thus, another important theme is into process or historical geomorphologists by "vivified by evolution." As noted by Judson that of tension between historical and dynamical their emphasis on time scales of study, and into (1958), the scientific program established by emphases in geomorphological research (Ritter, rational or empirical geomorphologists by their William Morris Davis merely followed in this 1988). scientific methodologies. Members of each trend. The Davisian emphasis on time-directed There are many sources of conflict in geo- group have their own sets of problems and may evolution of landscapes overshadowed the em- morphological research directions (Table 1). Geological Society of America Bulletin, v. 100, p. 1157-1167, 6 figs., 3 tables, August 1988. 1157 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/100/8/1157/3380275/i0016-7606-100-8-1157.pdf by guest on 28 September 2021 1158 V. R. BAKER TABLE 1. SOME CONFLICTING RESEARCH DIRECTIONS OR PROGRAMS IN FLUVIAL CEOMORPHOLOGY geological and geographical geomorphologists his geological colleagues with statements such as turned their attention to process studies. that at his Presidential Address to the Geological Geography Geology As stated by Thornes and Brunsden (1977): Society of America (Davis, 1912, p. 121): "all Process Historical "The current paradigm is one in which process geography belongs under geology, since geog- Empirical Rational Applied Basic studies prevail effected principally and increas- raphy is neither more nor less than the geology Experimental Field Quantitative Qualitative ingly by mathematical and stochastic models." of today." Indeed, fluvial geomorphology has been so in- Such statements did not reflect the main- fused by new research methods that those meth- stream of thinking in geography, where one Much has been written on these approaches to ods are determining the choice of appropriate could argue that empirical landscape description research by their adherents. Another area of geomorphological research problems. This has was preferable to hypothesizing genetic explana- conflict is the fundamental assumptions that un- resulted in the paradox described by Church tions. Questions of landform genesis can be con- derlie individual geomorphological investiga- (1980): "Contemporary process studies are of sidered irrelevant when concern is with the tions (Table 2). Whether termed "fundamental little worth in evaluating landscape evolution." human use of landscapes. Davis' explanatory concepts" (Thornbury, 1969), "philosophical The process studies most amenable to the new description was subjective and qualitative. By assumptions" (Twidale, 1977), "paradigms" method-dominated approach to geomorphology concentrating on objective, quantitative mea- (Oilier, 1981), or "basic postulates" (Pitty, may be largely irrelevant to the most important sures of slopes, spatial relationships, and so on, 1982), these ideas are the conventional wisdom scientific questions in problem-dominated ge- geomorphography could become more appro- for the science. Whereas the analysis of research netic geomorphology. The issues in this new cri- priate as a branch of geography. In being what directions must emphasize the backgrounds and sis for geomorphology are further complicated Cotton (1956) terms a "utilitarian art," geomor- methodologies of groups, the analysis of funda- by attempts by geomorphologists to make their phography would divorce itself from rational mental assumptions must emphasize the basic science more relevant in technical applications argument over landform genesis and concentrate philosophies of individuals. and more respectable in comparison to sister on an empirical approach that would be useful