The human role in changing fluvial systems: Retrospect, inventory and prospect

Historical and modern scientific contexts are provided for the 2006 Binghamton Geomorphology Symposium on the Human Role in Changing Fluvial Systems. The 2006 symposium provides a synthesis of research concerned with human impacts on fluvial systems — including hydrologic and geomorphic changes to watersheds — while also commemorating the 50th anniversary of the 1955 Man's Role in Changing the Face of the Earth Symposium [Thomas, Jr., W. L. (Ed.), 1956a. Man's Role in Changing the Face of the Earth. Univ. Chicago Press, Chicago. 1193 pp]. This paper examines the 1955 symposium from the perspective of human impacts on rivers, reviews current inquiry on anthropogenic interactions in fluvial systems, and anticipates future directions in this field.Although the 1955 symposium did not have an explicit geomorphic focus, it set the stage for many subsequent anthropogeomorphic studies. The 1955 conference provided guidance to geomorphologists by recommending and practicing interdisciplinary scholarship, through the use of diverse methodologies applied at extensive temporal and geographical scales, and through its insistence on an integrated understanding of human interactions with nature. Since 1956, research on human impacts to fluvial systems has been influenced by fundamental changes in why the research is done, what is studied, how river studies are conducted, and who does the research. Rationales for river research are now driven to a greater degree by institutional needs, environmental regulations, and aquatic restoration. New techniques include a host of dating, spatial imaging, and ground measurement methods that can be coupled with analytical functions and digital models. These new methods have led to a greater understanding of channel change, variations across multiple temporal and spatial scales, and integrated watershed perspectives; all changes that are reflected by the papers in this volume. These new methods also bring a set of technical demands for the training of geomorphologists. The 2006 Binghamton Geomorphology Symposium complements the 1956 symposium by providing a more specific and updated view of river systems coupled with human interactions. The symposium focuses on linkages between human land use, structures, and channel modification with geomorphology, hydrology, and ecology. The emergence of sustainability as a central policy guideline in environmental management should generate greater interest in geomorphic perspectives, especially as they pertain to human activities. The lack of theories of anthropogeomorphic change, however, presents a challenge for the next generation of geomorphologists in this rapidly growing subfield.     

Geomorphology's role in the study of weathering of cultural stone

Great monumental places—Petra, Giza, Angkor, Stonehenge, Tikal, Macchu Picchu, Rapa Nui, to name a few—are links to our cultural past. They evoke a sense of wonderment for their aesthetic fascination if not for their seeming permanence over both cultural and physical landscapes. However, as with natural landforms, human constructs are subject to weathering and erosion. Indeed, many of our cultural resources suffer from serious deterioration, some natural, some enhanced by human impact. Groups from the United Nations to local civic and tourism assemblies are deeply interested in maintaining and preserving such cultural resources, from simple rock art to great temples. Geomorphologists trained in interacting systems, process and response to thresholds, rates of change over time, and spatial variation of weathering processes and effects are able to offer insight into how deterioration occurs and what can be done to ameliorate the impact.Review of recent literature and case studies presented here demonstrate methodological and theoretical advances that have resulted from the study of cultural stone weathering. Because the stone was carved at a known date to a “baseline” or zero-datum level, some of the simplest methods (e.g., assessing surface weathering features or measuring surface recession in the field) provide useful data on weathering rates and processes. Such data are difficult or impossible to obtain in “natural” settings. Cultural stone weathering studies demonstrate the importance of biotic and saline weathering agents and the significance of weathering factors such as exposure (microclimate) and human impact. More sophisticated methods confirm these observations, but also reveal discrepancies between field and laboratory studies. This brings up two important caveats for conservators and geomorphologists. For the conservator, are laboratory and natural setting studies really analogous and useful for assessing stone damage? For the geomorphologist, does cultural stone data have any real relevance to the natural environment? These are questions for future research and debate. In any event, cultural stone weathering studies have been productive for both geomorphologists and conservators. Continued collaboration and communication between the geomorphic, historic preservation, archaeological, and engineering research communities are encouraged.     

系统论思想在地貌学中的应用

系统论的思潮及其基本原则迅速地向地貌学领域渗透和扩展,改变着地貌学家的知识结构和思维方式。愈来愈显示出地貌学的一个新的生长点——系统地貌学,将以其强大的生命力萌发出来。它将从系统论与控制论的角度,研究地球表面形态结构及其物质组成与自然环境、社会经济环境之间的相互作用,揭示地貌系统的结构、功能及其演化规律性;对地域分异形成的不同地貌景观,分别建立过程-反应模式。为优化人地系统、合理利用自然资源、建立区域发展最优模式的决策提供科学依据。     

Politicians and geomorphological blunders. Some examples relating to rivers and coasts from Queensland,Australia

Editors' Note: The following is the eighth in the Singapore Journal of Tropical Geography Lecture Series. It is based on the plenary presentation of 10 July at the 7th International Conference on Geomorphology held in Melbourne in 2009. Geomorphologists have an important role to not just understand and interpret the nature of processes operating within the physical landscape, but also to communicate this information to those who can use it to benefit society. Policy makers and legislators often develop documents relating to the management and use of landforms and landscapes that contain little or no input from geomorphologists, which can and do have undesirable consequences for governments, communities and the natural environment. Examples relating to rivers and coasts from Queensland, Australia highlight inadequacies in policies and legislation because of a lack of input from geomorphologists. In one instance the definition of a stream channel has been reinterpreted by the legal system because of a poorly developed definition within the legislation. The outcome is a legal definition of a stream channel based on the Q3 month flow (3‐month average recurrence interval discharge or flow). In another instance, people and property are being placed at risk from coastal erosion and impact from tropical cyclone generated marine inundations (waves and surge) because a lack of understanding of geomorphic processes operating along the coast has been inscribed into policies and legislation. These are examples from one region but similar situations will exist elsewhere globally. Both politicians and geomorphologists have a role to communicate better with each other about these matters. Geomorphologists in particular need to be more proactive in advising politicians on issues in which they have expertise.     

An approach for quantifying geomorphological impacts for EIA of transportation infrastructures: a case study in northern Spain

A methodological proposal for the assessment of impacts due to linear infrastructures such as motorways, railways, etc. is presented. The approach proposed includes a series of specific issues to be addressed for each geomorphological feature analysed—both ‘static’ and ‘dynamic’—as well as a series of steps to be followed in the process.Geomorphic characteristics potentially affected were initially identified on the basis of a conceptual activities/impacts model that helps to single out geomorphic impacts related to environmental concerns for the area. The following issues were addressed for each individual impact: nature of potential effects; indicators that can be used to measure impacts; criteria of ‘geomorphologic performance’; procedure for measurement/prediction of changes; translation of geomorphologic impacts into significant terms from the viewpoint of human concerns; possible mitigation and/or compensation measures.The procedure has been applied to a case study corresponding to a new motorway in the Basque Country, northern Spain. Geomorphological impacts considered in this analysis included: (1) consumable resources; (2) sites of geomorphological interest; (3) land units with high potential for use, high productivity or value for conservation; (4) visual landscape; (5) slope instability processes. The procedure has been designed for implementation in a Geographic Information System (GIS) environment. Details are given on the application of the method to each individual impact analysed and results are presented in both numerical and map form.Impacts assessed were initially expressed by means of heterogeneous magnitudes, depending on the geomorphological feature considered. Those geomorphological impacts were then translated into significant terms and homogeneous magnitudes. Integration was carried out on the basis of impact values thus obtained. Final integrated results were also expressed in numerical and map form.The method proposed enables comparison of alternatives as well as ‘prediction’ and assessment of impacts in terms directly related to geomorphic characteristics. It also facilitates the expression of those impacts in terms that allow integration with other types of environmental impacts.     

Teaching about relict, no-analog landscapes

Only a few very young landforms are the result of currently operating geomorphic processes. Because the time scale for landscape evolution is much longer than the time scale for late Cenozoic climate changes, almost all landscapes are palimpsests, written over repeatedly by various combinations of climate-determined processes. Relict glacial and periglacial landforms are widely identified in mid-latitude regions that have been traditionally described as having been shaped by the “normal” processes of fluvial erosion. Less confidently, deeply weathered regolith and associated relict landforms in the middle and high latitudes are attributed to early Tertiary warmth. However, assemblages of geomorphic processes specific to certain climatic regions, like faunal and floral assemblages, cannot be translated across latitude, so in spite of the many books about the geomorphology of specific modern climate regions, there are few sources that discuss former warm high-latitude, or cold low-latitude, low-altitude geomorphic processes that have no modern analogs. Students and teachers alike who attempt to interpret landforms by extrapolating modern climatic conditions to other latitudinal zones will find their outlook broadened, and they become better prepared to consider the geomorphic impacts of global climate change.     

The Promise for Geomorphic Discovery in the South

Abstract

Until recently a neglected region, renown for limited exposures, the southern United States is becoming an area of geomorphic discovery. This article presents an overview of current geomorphic research in this region, suggesting that despite past problems, academic geographers have made significant contributions to the geomorphology of the South in recent years. Research topics published on the region are highly varied, with some spatial bias as well as topical bias toward fluvial systems. Yet because of the limited historical work, much is unknown about these unique landscapes and their susceptibility to natural and human disturbances, and much benefit is to be gained from both applied and theoretical study of them.     

流水地貌实验的发展与创新——缅怀沈玉昌先生创建流水地貌实验室的历程

作为中国现代河流地貌研究的开拓者和奠基人,沈玉昌先生对开创流水地貌实验研究的初衷,为后人创新流水地貌实验开拓了先河,特撰写本文纪念先生100周年诞辰。主要内容有：①憧憬河流地貌实验与筹建流水地貌实验室。包括先生的初衷、实验室调研与筹建、实验试运行及起步实验;②流水地貌实验室扩建及实验研究蓬勃发展。包括结合国家重大及地方委托项目开展的一系列实验研究,开拓流域地貌系统及坡面发育演变的实验,建立河流地貌过程响应实验相似型理论;③河流地貌实验的新进展。包括河流地貌实验室建设及实验装置更新,河型系统发育演变过程实验的新进展,穹隆与坳陷非均匀升降对河流地貌系统发育影响的实验等。最后进行了展望,为了使中国实验流水地貌学研究继续深化,需要进行6个方面创新探索,特别是：加强构造运动、气候变化及人类活动快速变化导致的非稳定状态河流动力地貌过程实验研究,揭示其复杂性、敏感性及前兆性特征,加强实验研究力量的协作与融合,加强流水地貌实验研究的综合性、交叉性学术交流。     

A geomorphological approach to sustainable planning and management of the coastal zone of Kuwait

The coastal zone in Kuwait has been under a considerable pressure from conflicting land uses since the early 1960s, as well as from the destruction and oil pollution caused by the Gulf War. To avoid further damage and to protect the coastal heritage it is essential to adopt an environmentally sustainable management process. This paper shows how the study of coastal geomorphology can provide a sound basis for sustainable planning and management. Based on coastal landforms, sediments and processes, the coastline of Kuwait was divided into nine geomorphic zones. These zones were grouped into two main geomorphic provinces. The northern province is marked by extensive muddy intertidal flats and dominated by a depositional and low-energy environment. The southern geomorphic province is characterised by relatively steep beach profiles, rocky/sandy tidal flats and a moderate to high-energy environment. The study has demonstrated that pollution, benthic ecology and other environmental conditions of the coast are a function of coastline geomorphology, sedimentology and related processes. The geomorphological information was used to determine the coastal vulnerability and to assess the environmental impacts of development projects and other human activities. Several strategies were outlined to integrate the geomorphic approach into the management of the coastal resources.     

分形理论及其在地貌学中的应用──分形地貌学研究综述及展望

本文简介了分形的有关基本概念,回顾了分形理论在海岸、流水、喀斯特地貌等多种地貌类型和流域地貌发育的形态研究中,以及在地貌过程研究中的应用的新近成果,并提出了今后分形地貌学研究的五个主要方面.     

Aesthetics and relevance in geomorphological outreach

Aesthetics and relevance are essential for making geomorphology a discipline that appeals to the general public and to potential students. A concentration on process studies has led to a relative neglect of landforms, yet, it is landforms that have often stimulated geomorphologists themselves to become geomorphologists. The study and explanation of visually attractive landscapes, the demonstration of the relevance of the discipline to society's needs and, following on from that, a concern with global change, are three areas that need to be developed by geomorphologists.     

ANTHROPOGENIC GEOMORPHOLOGY IN NORTHERN ALASKA

Two classes of anthropogenic landforms can be recognized in the permafrost environment of northern Alaska. Primary anthropogenic landforms result from the operation of natural geomorphic processes on man-made features such as roads or gravel berms. Secondary anthropogenic forms are identical to natural geomorphic features, but evolve as indirect consequences of human actions. The first group is illustrated by a badly thermokarsted road, which has caused serious drainage disruptions likely to persist over a long time period. Secondary forms are exemplified by fields of palsa-like features, which are common where pipeline-related construction activities or structures cause shallow ponding. Because they evolve rapidly, anthropogenic permafrost landforms can provide great insight into the development of natural periglacial features.     

Using geomorphic understanding of catchment-scale process relationships to support the management of river futures: Macaé Basin,Brazil

Impacts of colonial settlement upon catchment-scale fluvial geomorphic relationships are reported for a relatively small catchment in northern Rio de Janeiro State, Brazil. Structural controls have induced the type and patterns of rivers in Macaé Basin. Fault block activity has resulted in steep, incised headwater streams above the escarpment. Confined and partly confined rivers in mid-catchment reaches of the rounded foothills have limited potential for geomorphic adjustment. Fluvial, estuarine and marine sediments in low relief landscapes of the lowland plain have supported the development of meandering sand bed rivers, with many cut-and-fill (intact valley fill) deposits in tributary systems. Indigenous people exerted relatively minor, localized impacts upon the geomorphology of this river system. Portuguese settlement since the sixteenth century brought about clearance of much of the Atlantic Forest of lowland reaches, and subsequent establishment of sugar cane and coffee plantations. Lowland reaches were channelized from the 1940s-1980s for flood protection and to support the expansion of pastoral agriculture. Significant adjustments have occurred to these geomorphologically sensitive reaches. In contrast, although rivers in the rounded foothills were impacted by forest clearance, the limited availability of sediment stores along these reaches has limited the extent of geomorphic responses to human disturbance. Relatively inaccessible upland reaches were even less impacted, and are now major conservation areas. Building on principles of the River Styles framework, catchment-scale evolutionary trajectories of rivers in the Macaé Basin are assessed based on analysis of patterns of river types, their capacity for adjustment and connectivity relationships, and responses to disturbance events. From this, three future scenarios of prospective evolutionary traits are developed: a ‘steady as she goes’ scenario, an optimistic (effective, proactive management) scenario, and a ‘doomsday’ scenario.     

Engineered channel controls limiting spawning habitat rehabilitation success on regulated gravel-bed rivers

In efforts to rehabilitate regulated rivers for ecological benefits, the flow regime has been one of the primary focal points of management strategies. However, channel engineering can impact channel geometry such that hydraulic and geomorphic responses to flow reregulation do not yield the sought for benefits. To illustrate and assess the impacts of structural channel controls and flow reregulation on channel processes and fish habitat quality in multiple life stages, a highly detailed digital elevation model was collected and analyzed for a river reach right below a dam using a suite of hydrologic, hydraulic, geomorphic, and ecological methods. Results showed that, despite flow reregulation to produce a scaled-down natural hydrograph, anthropogenic boundary controls have severely altered geomorphic processes associated with geomorphic self-sustainability and instream habitat availability in the case study. Given the similarity of this stream to many others, we concluded that the potential utility of natural flow regime reinstatement in regulated gravel-bed rivers is conditional on concomitant channel rehabilitation.     

Debris Flow Triggered by Rapid Snowmelt: A Case Study in The Glei .arhjalli Area, Northwestern Iceland

Debris flows in the Gleivarhjalli area in northwestern Iceland occurred after a sudden and intensive snowmelt period during 10–12 June, 1999. The area, in the northwestern part of the town of Ísafjörvur, was chosen for a detailed study. Meteorological data and bedrock conditions, triggering mechanisms and geomorphological and human impacts were examined. This paper describes and emphasises the role of rapid snowmelt as a mechanism for the release of debris flows in a subpolar basaltic fjord setting. Post‐event mapping of erosional and depositional landforms showed strong geomorphic impacts of debris flows and their role in mass transfer in a mountainous environment. The estimated denudation rate for the singleevent is 0.29 mm/km². The use of a new lichen growth curve provides relative dating of previous unreported events. Finally, the paper estimates the mean return period for debris‐flow events in the Gleivarhjalli area as 4–5 years, thus constituting a serious threat to the community.     

Landforms on Asteroid 25143-Itokawa: A geomorphological perspective on periglacial origin and meltwater history

Asteroid surface geology offers a full range of opportunities for geomorphologists to participate in the analysis of landform distributions, deposit composition, source areas for sediments, age estimations, and the reconstruction of geohydrological records. A recent touchdown (2005) on 25143-Itokawa, a Near Earth Object (NEO), by the Hayabusa Spacecraft provides imagery (released, 2008, by the Japanese Aerospace Agency) that allows the analysis of data relevant to geomorphologists. The abbreviated interpretation of landform distributions on Itokawa discussed below provides a preliminary analysis of landform morphogenesis in a cold climate with near-zero gravity. The analysis generates several questions related to source of water, cause of fluid propagation and explanations of previously unrecognized processes of denudation.     

Approaches to River Channel Sensitivity*

Much research in the physical and human sciences has addressed the concept of sensitivity to adjustment, including the analysis of geomorphological adjustment in fluvial systems. However, geomorphological sensitivity has been defined in numerous ways, partly because current conceptual understanding of the fluvial system exceeds modeling capabilities. Using published literature and analogies from materials behavior as a background, previous definitions are standardized and four hierarchically based interpretations are developed. The four interpretations, which relate to ratios, thresholds, recovery times, and sensitivity analysis, are explained and illustrated using a table that could be modified to apply to other environmental systems. Such standardized definitions of sensitivity should facilitate more precise communication between geomorphologists and guarantee effective use of the concept in analyses of the fluvial system.     

A heuristic model for potential geomorphic influences on trophic interactions in streams

Whereas certain linkages between stream channel morphology and stream ecology are fairly well-understood, how geomorphology influences trophic interactions remains largely unknown. As a first step, a simple, heuristic model is developed that couples reach-scale geomorphic morphology with trophic dynamics between vegetation, detritus, herbivores, and predators. Predation is assumed to increase with depth beyond a threshold depth, and herbivory is assumed to decrease with velocity beyond a threshold velocity. Results show that the modeled food chain is sensitive to channel geometry, particularly around the threshold conditions for predators and herbivores. Importantly, geomorphic influences are not isolated to a particular trophic level, but rather are transferred through the food chain via top-down and bottom-up effects. The modeled system is particularly sensitive to changes in the end-members of the food chain: vegetation and predators. Results illustrate that geomorphic disturbances, known to affect a single trophic level (e.g., fish), likely impact multiple trophic levels in the stream ecosystem via trophic interactions. Such impacts at the multiple trophic level are poorly understood. While limited by the lack of empirical long-term data for testing and calibration, this simple model provides a structure for generating hypotheses, collecting targeted data, and assessing the potential impacts of stream disturbance or restoration on entire stream ecosystems. Further, the model illustrates the potential for future coupled stream models to explore spatial and temporal linkages.     

Household level influences on fragmentation in an African park landscape

The process of landscape fragmentation outside park borders occurs through the actions of people living near the boundaries. In the Kibale National Park landscape in western Uganda, human-landscape relationships are typified by small-scale subsistence agriculture, in which households rely on resources provided in forests and wetlands, whose use is in turn shaped by perceptions of resource availability. To understand and manage for fragmentation of resource pools, modeling and identifying the proximate drivers, and thus enacted resource extraction and utilization – is of fundamental importance. We combine landscape analysis at the household scale, using remotely sensed data, with household surveys, to understand the potential human drivers of local scale landscape change. We found strong evidence for a local household zone (LHZ) effect on fragmentation patterns with geographical and socioecological heterogeneities in LHZ impact. Differences were influenced by wealth, and in some cases, tribal identity. The perception of crop raiders – primarily baboons and small monkeys, but also elephants and other animals – may have largely shaped human-environment interactions, and were associated with fragmentation. Ninety-two percent of the best fit models included the attitude that the park should stay, but associated it with increased fragmentation, suggesting that the uncharacteristic non-hostile attitude about Kibale does not directly translate into conservation-friendly local human-environment interactions. This study provides insight into park–neighbor interactions and the influence of the LHZ on protected-area landscapes, and it points to important points in the system for collaborative opportunities to engage communities and conservation managers.