Introduction
The questions on how does geomorphic diversity manifest itself in rivers and the reasons why is it considered an important component of a healthy system are the primary goals of this paper. In addition to that, an empirical study and observation should be revealed that implies the relativity of geomorphic complexity and diversity as well as the human modification of river systems. There have been various implications were in river systems appeared to be varied and difficulties arise when it comes to the determination of accurate measurements in different aspects of the elements of the ecosystem, rivers as such.
Overview of Geomorphology
Academically, geomorphology is the study of landforms and the processes that comprise the term. The people concerning the study basically aims at understanding the reasons why landscapes look the way they do such as further evaluating its history and dynamics, future changes, physical experiment, numerical modelling and other practices which attributes to environmental engineering (Chorley et al., 1985). Though geomorphology widely points out to the science of soil, other practical applications are accounted like measuring the effects of climate change, hazard assessments such as the prediction of landslides and mitigation, river control and restoration, coastal protection, and the assessment of the existence of water on Mars (Selby, 1985).
It is said that Chinese people were the first ones who formulated a theory of geomorphology wherein scientific observations were based on marine fossil shells in a geological stratum of a mountain hundreds of miles from the Pacific Ocean. An experiment on fossil shells was done and noticing that bivalve shells running in a horizontal span along the cut section of a Cliffside, an apparent theory was made that cliff was once the pre-historic location of a seashore that had changed several miles over the centuries.
Inferring that the land was reshaped and formed by soil erosion of the mountains and the deposition of silt prevailed when a thorough investigation of mountains, Taihang and Yandang mountains specifically (Selby, 1985). The theory of gradual climate altered over the years once an ancient petrified bamboo and found to be preserved underground on the dry, northern climate zone of a place. Relatively, in valley forms, the cycle was seen as a progression by which a river would cut a valley more and more deeply, but eventually, erosion of side valleys would then flatten out the terrain again hence now at a lower elevation. The cycle could be started over by uplift of the terrain.
Today, geomorphology centres on the quantitative analysis of interconnected processes such as the rates of steps of the hydrologic cycle, plate movement rates in order to compute the age and expected fate of landforms, weathering, the contribution of solar energy and the erosion of land (Knuepfer and Petersen, 2002).
Fluvial Geomorphology
In geomorphology, rivers and streams are not only channels of water, but also sediment. Water is capable of assembling sediment and transporting it downstream as a bed load or a dissolved load. The sediment rate transport primarily depends on the accessibility of sediment itself and on the discharge of the river. As the river flow across the landscape, it usually increases in size and merges with other rivers. The network of rivers apparently created becomes a drainage system and is often called dendritic. However, it may adopt other patterns that depend on the regional topography and underlying geology.
Rivers are known as a multifaceted system. The breadth and scope of research into fluvial geomorphology between the recent periods have revealed a systematic analysis of its complex systems. It has prevailed that forms of the river can be empirically studied through measurements or in a scale-sensitive hierarchal way. Studying the form, processes and behaviour of rivers require spatial and temporal intricacy of fluvial systems should as well be taken into account.
However, processes which involve small scale terms are still important and this should be vested in a general context of a long-term study. Likewise, Smith et al. (2002) in their writings, opposed that much of the gathered process knowledge should be utilized to bring longer-term and general scale points of views of landscape shift back to distinction. Fluvial geomorphology is also in a firm standing today than it ever has been.
Researches have widened and strengthened the adaptation of fluvial geomorphology in giving answers to various interdisciplinary problems (Conacher, 2002). This illustrates the opportunity and challenge with regard to the prevalence of fluvial geomorphology perspectives (Knuepfer and Petersen, 2002). Thus, diversification of rivers is important in the system certainly because it leads to the manipulation and shaping up of the morphology of the planet.
Discussion
River Styles Approach
Many geomorphologists account that recent environmental conditions are firmly contingent on the previous processes. Paleofluvial studies maintain to give significant clues with regard to the evolution of fluvial systems and the influence of the previous ones on the existing forms (Kraus, 2002). Similar threads that run through much of the paleofluvial researches is that the evolution of fluvial is impacted by multicausal drivers of diversified spatial and temporal dominance and intricacy. The drivers comprise sea-level and climate changes, variable sediment supply and transport, and tectonic activity (Mayer et al., 2003).
A diversity of morphological, lithological, palaeohydrological, pedogenetical, sedimentological and timing methods are performed to facilitate clarify the development of fluvial systems (Dambeck and Thiemeyer, 2002). While palaeofluvial research offers an important approach to the advancement of fluvial systems, the dent of the earlier period on present fluvial behaviour requests to be made precise to better comprehend the present-day forms and processes. An instance of how this can be overtly viewed is depicted on the River Styles Approach (Fryirs, 2002). The river styles approach shows how precursor controls such as various valley forms function under a set of boundary conditions that restrict form and processes at lower spatial scales as well as the temporal scale (Hunter et al., 1988).
The concept of the river styles approach perceives that geomorphic diversity needs to be determined and made known to be able to compare the similar ones to those which belong in the same clan. It implies that various basins or ecosystems have indeed dissimilar levels of buoyancy and can not be dealt with in a homogenous approach. Fryirs (2002) gives some guidelines for understanding geomorphic river conditions with the use of the river styles approach. This can be largely attributed to the natural formation of the resources depicting its own pattern of forming landscapes through the traces of its flows.
Sediment Transfer
One way of delivering sediment is the transfer of sediment from hillslopes to rivers, flood plains, lakes and transitional and coastal waters. The measurement of basin sediment budgets (Fuller et al., 2002), sediment delivery and sediment flux are vital for a profound understanding of the fluvial system. Deliverance is spatially and temporally highly changeable and it basically needs a hill slope to serve as a channel or flood plain combination.
As a result, the explanation of the record for determining sediment delivery is complex by buffering, most especially in bigger, and the application of techniques for estimating sediment gives way (Bartley and Rutherfurd, 2005).
Sourcing sediment is also vital for adhering to the grounds of transfer and for targeted management. Present advances and innovations in the techniques for discerning sediment sources offer important tools in this view and may give support in characterizing between human-induced and natural, active transformations. Essential lessons have not been learnt, as substantiation has made known that there is no simple relationship between event scale and sediment defer in basins, nor is there a plain association between river and flood plain sedimentation rates and event magnitude, frequency, timing or duration (Dendy and Bolton, 1976). Thus, sediment transfer is asynchronous with the commotion drivers and apparently demands a long-term perspective.
Geomorphology Predicts Biodiversity
Over the years, there has been a strong focus on the ecosystem or landscape-level conservation strategies was based on the presence of a particular species catered to a certain short-term benefit through long-term changes in the environment leaves particular species assemblages fleeting. According to the study of Burnett et al (1998), combining the biotic and abiotic landscape characteristics that were observed in the demographic location of the study enabled the researchers to utilize variables in order to predict the sumptuousness and woody plants species in diverse. The locations relatively possessed innate geomorphological heterogeneity that was backed up by woody floras than those of the areas of which has low geomorphological heterogeneity.
The results yield explicit importance with the respect to ecological theory however, there are inferences with regard to the management of biological resources and this should be treated in a fair manner (Nichols and Killingbeck, 1998). The presumption that biotic diversity is ecologically and aesthetically important has impelled conservation agencies and governments to recommend such protection and safeguarding for the landscape parcels which are biologically diverse.
It showed ecological value strategy used in the study through assessing the levels of biological richness and diversity is more often than not prevailed to be an expensive and time-consuming process. It had been determined that landscapes of high geomorphological heterogeneity have possibly supported varied biotic communities in previous years and will be positive in the future albeit the species composition of the communities will perpetually change over time (Burnett et al., 1998).
Arguments that safeguarding of regions with exceptional geomorphological properties is a demanded long-term conservation goal for the reason that those regions will normally back up a unique biota. Some studies provide a code of behaviour that falls into a mechanism that recognizes areas of high geomorphic heterogeneity (Nichols and Killingbeck, 1998). In addition, the existence or deficiency of certain species cannot be recognized with the study’s set of rules and yet it should be probable to use the ways to identify possible areas of such species with their respective habitat.
Variation in the cross-sectional asymmetry of coarse bedload River channels
Studies about the aspects of rivers and technical issues relating to the measurement of their width-depth properties and the like are certainly important for a deeper understanding of river systems. Different channels shapes can have similar measures and one author showed an exceptional technique to measure the given capacities. The non-existence of an index cross-sectional asymmetry has been a usual thing in nature channels and a significant aspect to the transformation of the cross-section in a plan form alter.
A particular index measures the imbalance of capacity in the middle of a bank full part, and was visualized and has been connected to other elements of channel morphology. Knighton (1981) has taken into account the requirements and figures of asymmetry indices in a specific and detailed way. An example is taken from the work of Milne (1983) wherein these ideas is revealed. At the outset, asymmetry indices are described as the measurement of an imbalance in a specific area, with respect to the cross-section limit, in a centerline or on the measurement s of the horizontal position of maximum depth and the connection between maximum and mean depth.
Innovations on Morphology
Innovations fluvial geomorphology is going through with the disciplines of the Earth Sciences through somehow, the outcome of the recent applications that were developed as a response to the emergence of computing science and new ways relates with the determination of computational fluid dynamics. Remote sensing, radiometric and methods on isotopes for numerical dating also relates to computing science.
Future trends in the fluvial geomorphology seemed to be interesting in line with the evolution of a long-term river and paleohydrology which benefits from recent methods and techniques. Also, this becomes more vigorous in creation upon the outcome of many decades of emergence in the study of the processes of river, experimental and numerical exemplars. The absence of linear response systems and various temporal and spatial scale substances that is required generally implies that understanding a connection or solving problems have to have the application of various tools.
The tools should operate in different temporal and spatial scales from basin studies up to particle movement as well as from geologic timescales to immediate measurements during investigational studies. There have been studies that reviewed the latest advances in the methods and techniques of researches that relate to the long term fluvial changes, ecological and management studies, and computational fluid dynamics and sediment transport (Fuller et al., 2002).
It had been clarified that fluvial morphology had benefited from assimilating studies of processes and had progressed in line with other recent disciplines such as the palaeohydrology when geomorphology gave the definition of geomorphology as the study of earth surface forms and processes and stated that geomorphology is widely an intellectual product of the twentieth century. There are comments which conjoined with the thrust of fluvial geomorphology in the later past and have been in the area of process studies (Dambeck and Thiemeyer, 2002).
It also implies that continuous reminders of the historical events on the variety of timescales can not be ignored. Palaeohydrology was one essential area that also benefited from an increasing range of techniques and focused research on particular areas that includes the temperate and the global scales thus it was consequently able to focus upon the links with environmental change and environmental management and global change. Hence, many of the fluvial research that was significantly geomorphological did not have to rely on under the title of fluvial geomorphology because of the extensions of techniques and the way wherein the multidisciplinary study integrates with other areas (Dambeck and Thiemeyer, 2002).
As such, fluvial research that involves both landform formation and process attributed less percentage of the wide- range researches during the year 1975 and water-related studies were lesser than those that were depicted on the publications for 1996 in most universities. However, not all the researches were determined as fluvial geomorphology. At the last phase of the twentieth century, a number of applications of fluvial geomorphology as well as technical advances in computing sciences and accumulation of data stood to bring about recent advances of the discipline.
Moreover, fluvial geomorphology and engineering of the river are conjoining as each separate principle considers the profit of the other viewing the positive outcome of the fluvial geomorphology approach that connects site-specific limitation on the conditions and predictions of morphological behaviour on the real-time and spatial scales. Thus, applied fluvial geomorphology for engineering a river and management for the specific areas of a higher level were determined that the control over the widespread application of a geomorphological approach to be able to enhance river management.
This includes the recent innovations in geomorphology, and not like the open channel hydraulics which comprises the collection of a large set of information as a field science but utilizes other sources. More often than not, geomorphological advice is linked with the advice given by the conservationists and a group for a single issue (Fuller et al., 2002). In addition, geomorphology runs through a longer framework than in many other applied sciences.
Reviewing the foundation to river channel management and fluvial geomorphology was just a highlight considered for the contributions made with others that include ecology, hydrology, environmental sciences, philosophy and engineering (Fryirs, 2002). Therefore, as the fluvial geomorphology has been refreshed, it appears to be at a more multidisciplinary level and thus recommended for an instance that fluvial geomorphology is increasingly becoming overtly involved in practical application in order to back up the plans of contingencies for the management of river basin.
Morphologic Assessment
Assessing the morphologic complexity and diversity in river systems using three-dimensional asymmetry indices for bed elements, bedforms and bar units comprise of various methods. One way of assessing the morphologic diversity is by the use of unevenness which is an appraisal of how disturbed a feature is in terms of its form (Knighton, 1981; Milne, 1983) or process which Knighton (1984) coined.
In geomorphology, unevenness or asymmetry depicts a propensity on the irregularity and complication and natural streams which typically shows asymmetrical cross-sections over much of their length where human-made channels are more often than not highly symmetrical than those made naturally. To specifically point out the instances, ideas of fluvial form asymmetry have been restricted to evaluating the cross-sectional asymmetry as cited by Milne (1979) (1983) and Knighton (1981). Taking into account the asymmetry in more than one plane, at various flow stages or over a diversity of spatial scales have actually not been assumed nor do not have accurate tools to be able to conduct certain assessments.
Developments basically depend on the ascending multidisciplinary inclusion of the respective papers and their applications. Hence, in the case of river systems, an approach that comprises of the river habitat problems should take the freshwater biologists or ecologists in a relative evaluation (Fryirs, 2002). Association with ecology has been specifically beneficial. One analytical paper showed that links between geomorphology and ecology were explored more broadly. A beneficial joint has emerged into the comprehension of ecological systems and geomorphology of fluvial systems with connection to the riparian sedimentation.
Conclusion
Adhering to the geomorphic diversity of rivers and its reasons why they prevailed to be a significant element of a healthy system comes into the perspectives of natural approaches of the river systems. The river styles approach demonstrates how such resources are developed through the natural forces of river flows. It appears to be significant because such a way distinguishes a healthy system from whatnot.
Fluvial geomorphology has a lot to offer in a scientific view and as a foundation for managing multifaceted river systems. One determined strength is that it sees the world as a nested hierarchal system wherein consideration of spatial and temporal scale gives the whole principle for understanding the composition of such system behaviour. This merely illustrates a helpful perception that contributes to the considerable importance and gives more views with regard to the elucidation of the natural world which is identified by intricate multiscale and multidimensional dilemmas (Dambeck and Thiemeyer, 2002).
The extensiveness of the research tool account for some studies and demonstrated that within a general perspective, there is space for a variety of spatial and temporal scales which offers a potentially holistic consideration of river behaviour. Some of the future progress in fluvial geomorphology will rely on its capability to comprehend and evaluate the links within and associations between patches of fluvial forms and processes at different spatial and temporal scales.
Current trends in fluvial geomorphology have been widely considered by the set of techniques that are available and certainly, this caters to the techniques which will reveal apparent outcomes. Suggestions of present accomplishments are given in the development of reports that are viewed by some authors (Dambeck and Thiemeyer, 2002). Fluvial geomorphology needs to be more linked with the basic scientific issues or to the solution of opening societal problems.
The successive reviews made by many writings, though the accreditation of recent emphasis upon applied interdisciplinary research, focus upon fundamental fluvial science with particular orientation to the ways in which channel and valley properties respond to long-term effects of climate change and tectonic activity and in the short term on how information on the intrinsic characteristics and evolution of rivers is required to explain an ongoing process (Dambeck and Thiemeyer, 2002).
Human-driven fluvial systems are said to be more accurate in measures because this has to comply with the specifications of phenomena that may largely have an impact on the development of other natural resources. Forces are the ones that drive the variation among river systems and it just strongly depicts an idea that falls under the ideas the strength of such natural resources should respectively be viewed as a powerful tool in shaping geomorphology of different branches not only river systems (Knighton, 1981; Milne, 1983).
This portrays a string variable among other systems because rivers and streams usually carry the shaping of other landforms such as transferring sediments to other landforms as well as forming new resources. Ideas should be treated in both scientific and technical aspects on the processes of creation. Humans are capable of forming such landscapes as well as the work of natural resources but still, the two differs in many ways. These differences can be largely depicted through various techniques developed by geomorphologists in modern times.
Many studies are cited and considered intricacy on morphologic issues with regard to the diversity of fluvial forms which are found in a system (Fuller et al., 2002). It was shown that less usual although considering the internal inconsistency that exists in a simple morphologic structure may largely affect and contribute to eh difficulty and diversity of the larger system. It is important to note that exceptions comprise of the present works on big woody debris whereby researchers started the various utilization of variables and how this impacted geomorphology and ecology. However, a cohesive approach is still needed for the further development of a profound and substantial perspective regarding these ecological issues.
References:
Bartley, R., Rutherfurd, I. , 2005. Measuring the reach-scale geomorphic diversity of streams: application to a stream disturbed by a sediment slug. River Research and Applications, 21: 39- 59.
Burnett, M.R., August, P.V., Brown, J.H., Killingbeck, K.T., 1998. The influence of geomorphological heterogeneity on biodiversity. 1. A Patch scale perspective. Conservation Biology, 12: 363-370.
Chorley, Richard J., Stanley Alfred Schumm and David E. Sugden (1985). Geomorphology. London: Methuen.
Conacher, A. 2002: A role for geomorphology in integrated catchment management. Australian Geographical Studies 40(2), 179–95.
Dambeck, R. and Thiemeyer, H. 2002: Fluvial history of the northern Upper Rhine River (southwestern Germany) during the Lateglacial and Holocene times. Quaternary International 93–94, 53–63.
Fryirs, K. 2002: Antecedent landscape controls on river character, behaviour and evolution at the base of the escarpment in Bega catchment, South Coast, New South Wales, Australia. Zeitschrift fu¨ r Geomorphologie N.F 46(4), 475–504.
Fuller, I.C., Passmore, D.G., Heritage, G.L., Large, A.R.G., Milan, D.J. and Brewer, P.A. 2002: Annual sediment budgets in an unstable gravel-bed river: the River Coquet, northern England. In Jones, S.J. and Frostick, L.E., editors, Sediment flux to basins: causes, controls and consequences. London: Geological Society, Special Publications 191, 115–31.
Dendy, F.E. and Bolton, G.C. 1976: Sediment yield runoff- drainage area relationships in the United States. Journal of Soil and Water Conservation 31, 264–66.
Hunter, M. L., Jr., G. L. Jacobson, Jr., and T. Webb III. 1988. Paleoecology and the coarse-filter approach to maintaining biological diversity. Conservation Biology 4:375–385.
Knighton, A.D., 1981. Asymmetry of river channel cross-sections: Part 1. Quantitative indices. Surface Processes and Landforms, 6: 581-588.
Knighton, A.D., 1982. Asymmetry of river channel cross-sections: Part 2. Mode of development and local variation. Surface Processes and Landforms, 7: 117-131.
Knighton AD. 1984. Indices of flow asymmetry in natural streams: definition and performance. Journal of Hydrology 73: 1–19.
Knuepfer, P.L.K. and Petersen, J.F. 2002: Introduction: geomorphology in the public eye: policy issues, education, and the public. Geomorphology 47, 95–105.
Kraus, M.J. 2002: Basin-scale changes in floodplain paleosols: implications for interpreting alluvial architecture. Journal of Sedimentary Research 72(4), 500–509.
Mayer, L., Menichetti, M., Nesci, O. and Savelli, D. 2003: Morphotectonic approach to the drainage analysis in the North Marche region, central Italy. Quaternary International 101–102, 157–67.
Milne JA. 1979. The morphological relationships of bends on confined stream channels in upland Britain. In Geographical Approaches to Fluvial Processes, Pitty AF (ed.). Geobooks: Norwich; 215–239.
Milne, J.A., 1983. Variation in cross-sectional asymmetry of coarse bedload river channels. Earth Surface Processes and Landforms, 8: 503-511.
Nichols, W.F., Killingbeck, K.T., August, P.V., 1998. The influence of geomorphological heterogeneity on biodiversity. 2. A landscape perspective. Conservation Biology, 12: 371-379.
Selby, Michael John (1985). Earth’s changing surface: an introduction to geomorphology. Oxford: Clarendon Press.
Smith, B.J., Warke, P.A. and Whalley, W.B. 2002: Landscape development, collective amnesia and the need for integration in geomorphological research. Area 33(4), 409–18.