Applied Geomorphology: Concept and Applications

There has been increasing recognition of the practical application of geomorphic principles and the findings of geomorphological research to human beings who are influenced by and, in turn, influence the surface features of the earth. Continuous increase in population has led to pressure on land resources, and an extension of agriculture to hilly and marginal lands resulted in man-induced catastrophes like soil erosion, landslides, sedimentation and floods.

A proper interpretation of landforms throws light upon a region’s geologic history, structure, and lithology. As geology becomes more specialized, there is a growing possibility that the application of geomorphology to problems of applied geology will be overlooked.

The role of applied geomorphology relates mainly to the problems of analyzing and monitoring landscape-forming processes that may arise from human interference. Human beings have, over time, tried to tame and modify geomorphic/environmental processes to suit their economic needs. Geomorphology has diverse applications over a large area of human activity, and geomorphologists may serve the need of society.

Definition of Applied Geomorphology

Applied geomorphology is a field of science where the research outcomes provide information on geomorphic landforms or processes that may be of concern to society and, where relevant, provide solutions to problems of geomorphic context. Applied geomorphology examines geomorphic impacts that affect society, as well as society’s impact on geomorphic forms and processes. (Meitzen, K.M., 2017)

The applications of geomorphic knowledge to problem-solving spans all of the traditions of geomorphology and are useful for human-environmental solutions across a broad range of geographies, including coastal shoreline erosion control, landslide risk assessments, and dam-related river management issues.

Resources, particularly maps, models, and prediction tools, provided by applied geomorphologists are useful to scientists, engineers, consultants, and decision-makers involved with hazards, land-use planning, natural resources, environmental management, and global environmental change. (Meitzen, K.M., 2017)

Application of Geomorphology in Different Fields

Application of Geomorphology in Hydrology

Water, either on the surface of the earth or groundwater used by humans, is available from different sources like streams, lakes and rivers. The lithological zones present different conditions of surface as well as groundwater.

Hydrology of Limestone Terrains

A comprehensive understanding of geomorphology is key to understanding the hydrological problem of the limestone terrain. The limestone region yields more water than others due to its rock formation. The availability of water in limestone regions depends on the type of rock.

Based on Permeability, limestone rocks may be primary or secondary. Calcareous sediments decide the formation of rock and its primary permeability, while earth movements in the form of tension and compression such as faulting, folding, warping, and due to solution or corrosion mechanism decide the secondary permeability.

Joints and fractures produced by diagenetic and diastrophic processes formed the secondary or acquired permeability, resulting in a solution. The cavities of the solution in the limestone region depend on whether it has been situated in the past or allows joints and bedding planes to be actively enlarged.

In Florida (USA), these solution cavities are common at considerable depth in the Tertiary limestones. The significance of solutional opening with increased permeability is important in present-day topography but also in karst landscapes too.

Geomorphology plays an important role to obtained water in limestone regions. Obtaining water from wells in limestone terrain may be easy or difficult. There may not be difficulty in obtaining wells of large yields if the limestones have enough permeability and are capped with a sandstone layer.

In such cases, the yield of water may be low or inadequate but subject to contamination. Karst plains lack filtering cover, and any swallow holes, sinkholes, or karst valleys within an area of clastic rocks should cast doubt upon the purity of the water of springs.

Glaciated Areas and Groundwater

Preglacial and glacial time history, types of deposits and landforms determine the possibilities of large supplies of groundwater potentials in glaciated regions. The yield of a large volume of water obtained from Outwash plains, valley trains, and enter till gravels or buried outwash.

Due to clay content, most of the aquifers are poor, but containing local strata of sand and gravel may hold and supply enough water for domestic needs. The study of preglacial topography and geomorphic history of the area could detect the presence and absence of underground water.

Application of Geomorphology in Mineral Exploration

There is a close association between geological structure and mineral deposits. Characteristics of landscapes of specific areas could indicate these geological structures. Economic geologist has not appreciated the exploration of some minerals in the name of understanding the geomorphic features and history of a region. In the search for mineral deposits, these three points may serve for Geomorphic features:

1. Some minerals have a direct topographic expression for their deposits.
2. An area’s geologic structure and topography have a correlation which clues to the accumulation of minerals.
3. Geomorphic history indicates the physical condition under which the minerals accumulated or were enriched in a particular area.

Surface Expression of Ore Bodies

Some ore bodies have surface expression, but many do as topographic forms, as outcrops of ore, gossan, or residual minerals, or as such structural features as faults, fractures, and breccia zones. Not all ore outcrops need to be reflected in positive topographic forms. The lead-zinc lode could be marked by a conspicuous ridge in the case of Broken Hill, Australia.

Quartz veins could stand out prominently as they are much more resistant to erosion than the unsilicified rocks, as in Chihuahua, Mexico. Some veins and mineralized areas may lack conspicuous topographic expression or be reflected by subsidence features or depressions.

Though no generalization can be made about the exact type of topography necessary for iron ore accumulation, distinct topographic expression is needed for a particular deposit. Residual iron deposits are the results of the concentration of iron due to long periods of weathering, and thus for their accumulation, old erosion and weathering surfaces are favourable sites.

Weathering Residues

Geomorphology can play an important role in several important economic minerals, essentially weathering residues of present or ancient geomorphic cycles. Apart from iron deposits, materials like clay minerals, caliche, bauxite and some manganese and nickel ores are of this nature. Recent weathering surfaces may exhibit residual weathering products or lie upon ancient weathering surfaces that are now buried.

Peneplain or near peneplain surfaces are the most common surfaces upon which they form. In general, such minerals are to be found upon remnants of tertiary erosional surfaces above present base levels of erosion.

It is not yet clear why the weathering of igneous rocks produces both clay minerals or hydrous aluminium silicates and hydrous oxides of aluminium, such as bauxite. The difference in the final product is determined by the climatic conditions under which weathering takes could be one of the explanations.

The residual products from the weathering of igneous rocks are clay minerals found in temperate climates known as kaolinization. It should be recognized that numerous minerals other than kaolin may form in the same climate. On the contrary, under tropical climates, final weathering products are hydrous oxides of such metals as aluminium, manganese and iron. This type of weathering is known as lateralization.

The phase of geology, which concerns the recognition and study of ancient weathering surfaces and soil, has come to be known as paleopedology. Though it offers many possibilities but still in its infancy in the search for the type of mineral deposits designated as weathering residues of the geological phase.

Epigenetic Minerals and Unconformities

Ancient erosion surfaces are associated with numerous deposits of Epigenetic minerals. Mills and Eyrich (1966) emphasized the role played by unconformities in the localization of mineral deposits.

The mineral deposits found from the ranging age of Precambrian to Tertiary show pieces of evidence of close association with unconformities in districts of the US and Canada; such minerals are uranium, vanadium, copper, barite, fluorite, lead, nickel, and manganese. There is constant work of weathering and erosion on the rocks of the earth’s surface, and this weathering work has an economic value of rock product.

Placer Deposits

Placer deposits are mixtures of heavy metals with specific locations; geomorphic principles have been applied other than any other phase of economic geology. Geomorphic processes are the main cause of placer concentration of minerals found in specific positions with distinctive topographic expression.

The deposition of placers is affected by the type of rock forming the bedrock floor. There are as many as nine types of placer deposits. They are residual or ‘seam diggings’, colluvial, eolian, bajada, beach, glacial including those in end moraines and valley trains, and buried and ancient placers. The most important among them is alluvial placers.

The other name of Residual placers is ‘seam diggings’, residues from the weathering of quartz stringers or veins that are usually of partial amount and grade down into lodes. Creep down the slope is the main reason for the production of colluvial placers and is thus transitional between residual placers and alluvial placers.

Most of the gold placers of this form have been found in California, Australia, New Zealand, and elsewhere. Colluvial placers (the koelits) and alluvial placers (the kaksas) are parts of the tin placers of Malaya. The most important minerals like gold, tin and diamonds are obtained from alluvial placers. South Africa’s diamonds from Vaal and Orange River districts, the Lichtenburg area, the Belgian Congo, and Brazil’s Minas Geraes, are obtained from alluvial placers.

Placer deposits have a total share of around 20 per cent of the world’s diamonds. Australia, lower California, and Mexico have yielded gold in aeolian placers. Gold in California and Alaska, diamonds in the Namaqualand district of South Africa, zircon in India, Brazil, and Australia, and ilmenite and monazite from Travancore, India have yielded from beach placers.

Oil Exploration

Several oil fields have been discovered because of their striking topographic expression. These oil fields are characterized by anticlinal structures which are strikingly reflected in the topography. When viewed from aerial photographs, many of the Gulf Coast salt dome structures are evident in the topography.

For the student of geomorphology, it is a fairly good working principle to suspect that areas that are topographically high may also be structurally high, where possibilities of topographical inversion at the crest of a structural high may result in weak beds.

In regions of heavy tropical forest, topography cannot be seen through the intense forest cover; an anticlinal or domal structure may outline due to the tonal differences in the vegetation. In the search for oil, more subtle evidence of geologic structures favourable to oil accumulation is being made. Aerial photography is one such technique through which drainage analysis of a terrain can be shown.

Drainage analysis is useful, particularly in regions where rocks have low dips and the topographic relief is slight. Permeability may be either primary or secondary in carbonate rocks. The number of large oil yields from limestone has been obtained from rocks which have a high degree of permeability produced by solution.

Elongated buried sand bodies are shoestring sands. Probably there is no phase of petroleum exploration which can use to better advantage knowledge of the in-depth characteristics of specific topographic features than that which deals with the misuse of shoestring sands. Most of the oil and gas sources are associated with unconformities – ancient erosion surfaces; hence a petroleum geologist must deal with buried landscapes.

Application of Geomorphology in Engineering Works

Evaluation of geologic factors of one type or another often involve in most engineering projects; among all the factors, terrain characteristics are the most common. A detailed study of the geomorphic history of an area may support the proper evaluation of surficial materials and the bedrock profile configuration.

Road Construction

Topographic features of an area determine the most feasible highway route. Road engineering faces several problems with different types of terrain that includes geologic structure, geomorphic history of the area, lithological and stratigraphic characteristics and strength of the surficial deposits.

Areas like karst plains require repeated cut and fill; if not done, then the road will be flooded after heavy rains with surface runoff from the sinkholes. The presence of enlarged solutional cavities in the karst region emphasises the design of roads in such a way that roads should not be weakened.

Region-like glacial terrain presents several engineering problems. Road construction in flat till plain is topographically ideal but in other areas where moraines, eskers, kames or drumlins-like features exist there is a need for cut and fill to avoid circuitous routes.

Areas which are characterized by late, youth and maturity of relief will require more bridge construction and many cuts and fills. These types of areas are consistently facing problems like landslides, earth flows, and slumping.

Landslides and different types of mass-wasting present problems not only in different engineering phases but also in highway construction. Subgrade or the soil beneath a road surface, has become more significant because of its control over the drainage beneath a highway; therefore construction design of the highway should be in such a way as to carry heavy traffic.

Two factors largely determine the lifetime of a highway under moderate loads are the quality of the aggregate used in the highway and the soil texture and subgrade drainage. The type of parent material and the relationships of soils to their varying topographic conditions are essential in modern road construction.

The most serious problem encountered by highway engineers is Pumping which means the expulsion of water from beneath road slabs through joints and cracks. Pumping is particularly greater over glacial till than over permeable materials such as wind-blown sand and outwash gravel.

Poor drainage in a subgrade is mainly responsible for pumping. Poor and best performance of the highway is characterized by silty-clay subgrades with a high water table and granular materials with a low water table, respectively.

Dam Site Selection

A synthesis of knowledge concerning the geomorphology, lithology, and geologic structure of terrains has greatly helped while selecting sites for dam construction. According to Bryan, five main requirements of good reservoir sites depend on geologic conditions:

1. adequate size water-tight basin
2. a narrow outlet of the basin with a foundation that will permit the economical construction of a dam
3. to build an adequate and safe spillway to carry excess water
4. availability of resources needed for dam construction (earthen dams) and
5. Assurance that excessive deposition of mud and silt will not shorten the life of the reservoir.

Constructing a dam in a Limestone terrain may prove a difficult one; for instance, the Hondo reservoir was built over limestone in southeastern New Mexico with a water table some 20 feet below the surface. Rapid Leakage was the cause of the abandonment of the reservoir. Building a dam in a valley may not be a good dam site from the standpoint of the dam’s size.

Buried bedrock valleys containing sand and gravel fills are common in glaciated areas, which may not depict an adequate picture of surface condition. Making a dam on those sites where subsurface topography is not supportive of the buried preglacial valley with sand and gravel in it would have a chance of leakage.

Location of Sand and Gravel Pits

Sand and gravel have more commercial and industrial uses than many engineering. Evaluation of geologic factors such as variation in grade sizes, lithologic composition, degree of weathering, amount of overburden, and continuity of the deposits are important while selecting suitable sites for sand and gravel pits.

Floodplains, river terraces, alluvial fan and cone, talus, wind-blown, residual, and glacial deposits of various types are areas where sand and gravel may be found in abundance. In recent years, there is a great demand for gravel than sand due to decreased use of plaster in home construction therefore knowledge of various grade sizes is more important.

There are high proportions of silt and sand in floodplain deposits which show many variable and vertical gradations and heterogeneous lateral. With their angular shape as well as a variable in size, alluvial fan and cone gravels are found near their apices. Being angular like talus, materials are too large to be useful and are limited in extent. There is only sand in wind-blown sands but no gravel.

Residual deposits are likely to contain pebbles that are suitable for cement work. These residuals are also limited in extent. Favourable sites for pits are terraced valley trains and outwash plains, which are usually extensive and do not have a thick overburden. Due to its large amount of material, kame deposits show a poor degree of assortment because it discarded on the ground as too large or too fine.

Application of Geomorphology in Military Geology

Allied powers during world war were slow to make the maximum use of geology in warfare. Geologists were utilized but to a limited extent in World War I. Before military authorities saw the need for and possibilities of the use of geologic experts, the war was well-advanced. During wars, useful information was more geologic than geomorphic in nature.

The information regarding digging trenches, mining, countermining, water supply or other material was not utilized. Topography became more important during World War II with the development of the blitzkrieg type of warfare because the effectiveness of a blitz depends to a large extent upon the trafficability of the terrain. In recent years terrain appreciation or terrain analysis has become more important in the military.

For a terrain, if geological maps fail somewhere, the geological principles can be applied with the advantage of interpreting the terrain from aerial photographs. Little training is required to recognize features like mountains, hills, lakes, rivers, woods, plains or some kinds of swamps. It is important to know the kind of hill, plain, river or lake, and so on because by knowing this it is quite possible to reconstruct the geology of that region.

Aerial photographs are useful for preparing terrain intelligence as they provide information on the area’s geology. The terrain has been an important factor in the Korean War and the fighting in the Vietnam region. With the development of the atomic bomb and ballistic missiles, topography would no longer play an important role in wars but confined to the local areas for war purposes.

Application of Geomorphology in Regional Planning

Geomorphologic information can be utilized at various levels of planning. A combination of topographic information, soils, hydrology, lithology, terrain characteristics and engineering included on terrain maps make it suitable for regional planning.

Applied geomorphology has a distinct place in regional planning. At the broadest scale, it can be used as delineate areas for the forest, mountain, plateau, recreational, rural and urban areas.

A balanced growth of a country’s economy requires a careful understanding of its natural resources and human resources. Rural or underdeveloped terrain fulfils a variety of recreational needs. There is a transformation from terrain maps into land-use suitability maps to develop rural and urban areas. Detailed information on topography enlightened regional planners who may then advise development projects best suited for the separate region.

Application of Geomorphology in Urbanisation

There is a separate branch known as urban geomorphology applied to urban development. According to R.U. Cooke, this branch of geomorphology is concerned with “the study of landforms and their related processes, materials and hazards, ways that are beneficial to planning, development and management of urbanized areas where urban growth is expected”.

Geomorphic features decide the stability, safety, basic needs and even its expansion. That means city or towns entirely depends on lithological and topographical features, hydrological conditions and geomorphic features.

Urban geomorphologists commence even before urban development through field surveys, terrain classification, identification and selection of alternative sites for settlements irrespective of plain or hilly areas. These urban geomorphologists would be concerned with the impact of natural events on the urban community and that of urban development on the environment.

When geomorphological problems are not understood by planners and engineers then it leads to destruction and damage to urban settlements in different environmental regions. Settling of foundation material in dry or glacial regions, weathering processes, and damages to roads and buildings through floods in many parts of the world are not recent phenomena.

These problems arise due to a misunderstanding of the geomorphological conditions. In developing countries, attention has not been given to the geomorphological conditions before the development of existing urban centres. This leads to the haphazard growth of cities with squatter settlements and shanty towns with urban morphology.

Application of Geomorphology in Coastal Zone Management

Coastal zones are not linear as a boundary between land and water but rather viewed as a dynamic region of the interface of land and water. The major threat to the fragile coastal zone is its deteriorating coastal environment through shoreline erosion, loss of natural beauty, pollution and extinction of species coastal zone management requires an integrated approach. The most widespread material is beach sand, found mainly in low latitudes. Beach sand and gravel are widely used in the construction industry.

Geomorphologists have contributed significantly to understanding shoreline equilibrium in Eastern Australia, where considerable sand mining for heavy minerals has been developed. Some measures have been designed for coast protection, including sea defence structures such as seawalls, breakwaters, jetties and groynes.

To protect the sea backshore zone from direct erosion cut, sea walls are designed since these walls are impermeable; they increase the backwash and produce a destructive wave effect. Breakwaters can be built either normally or parallel to the coast. Monitoring and quantifying wave conditions, tidal currents and sediment movement in the nearshore zone is necessary to evaluate how sea defences and other man-made structures affect shoreline equilibrium.

In the context of coastal zone management Hails emphasizes that applied geomorphology must be concerned with quantitative and not descriptive research to obtain relevant and accurate data on:

• (i) natural erosion and deposition rate
• (ii) at what rates and amount of the sediment transport from river catchments to the nearshore zone
• (iii) variations in sediment composition and offshore distribution
• (iv) sand supply sources and shoreline equilibrium
• (v) interchange rate of sand between beaches and dune systems
• (vi) the effects of constructing sea defences
• (vii) offshore sediment dispersal and the dredging effects of seabed morphology, sediment transport and wave refraction; and
• (viii) analysis of landform, including the topography of the near-shore zone, the form of the continental shelf and relict coastlines, particularly in terms of rock outcrops.

The above investigation provides relevant baseline data for the systematic planning process, monitoring programmes, and land use schemes.

Application of Geomorphology in Hazard Management

Hazards can be put in natural or man-induced where the tolerable level or unexpected nature exceeds. According to Chorley, the geomorphic hazard may be defined as “any change, natural or man-made, that may affect the geomorphic stability of a landform to the adversity of living things”.

These hazards may arise from immediate and sudden movements like volcanic eruptions, earthquakes, landslides, avalanches, floods, etc. Faulting, folding, warping, uplifting, subsidence, or vegetation changes and hydrologic regime due to climatic change arise from long-term factors.

Areas with past case histories of volcanism and seismic events help predict possible eruptions and earthquakes, respectively. Regular monitoring of seismic waves, measurement of the temperature of craters, lakes, hot springs, and geysers and changes in the configuration of volcanoes, whether dormant or extinct, can reduce the hazard to some extent. A detailed knowledge of topography can predict the path of lava flow and its eruption points in advance.

The behaviour of a river system can be well understood by its geomorphic knowledge through its channel, morphology, flow pattern, river metamorphosis and so on. It may help to control excess water in rivers and control measures during flood season.

Prior knowledge of erosion in the upper catchment area and carrying sediments to its proportion may help in understanding the gradual rise in the river bed, which may lead to a levee breach and cause sudden floods.

Earthquakes may be man-induced or natural geomorphic hazards. Detailed study of seismic waves region would help in identifying and mapping the zones of high to low intensity to reduce the risk to human life.

Other Applications of Geomorphology

Some of the applications of geomorphic principles have been used in applied geomorphology but there are other fields where geomorphic knowledge of the terrain is more important. Soil maps to some extent are topographic maps and differences in soil series fundamentally rest upon topographic conditions under which each portion of soil series developed.

Soil erosion-related problem is essentially a problem involving the recognition and proper control of such geomorphic processes as sheet wash erosion, gullying, mass-wasting, and stream erosion. The angle of slope is not a single factor that determines the severity of erosion.

With the introduction of air photographs and satellite imagery, the preparation of specialized maps and interpreting them has become easier and more accurate. Nowadays, aerial photographs are being used for evaluating landforms and land use for city developmental plans, construction projects, highways etc.

Another tool i.e. Remote sensing, is necessary for sustainable management of natural resources like soil, forest, crops, oceans, urban and town planning etc. At present Geographical Information Systems (GIS) technology has been used along with Remote Sensing techniques in geomorphic features interpretation.

All fields discussed in this chapter should be sufficient to show an understanding of the geomorphic principle; besides the geomorphic history of a particular region, geomorphic features may contribute in applied geology to the solutions of problems. The application of geomorphology can be of immense use to control the adverse effects of human activities on geomorphic forms and processes.

Read More in Geomorphology

1. Earth Movements: Meaning and Types
2. Epeirogenic Earth Movements
3. Orogenic Earth Movements
4. Cymatogenic Earth Movements
5. Concept of Stress and Strain in Rocks
6. Folds in Geography
7. Fault in Geography
8. Mountain Building Process
9. Morphogenetic Regions
10. Isostasy: Concept of Airy, Pratt, Hayford & Bowie and Jolly
11. Continental Drift Theory of Alfred Lothar Wegener (1912)
12. Plate Tectonics: Assumptions, Evidences, Plate Boundaries and Features Formed
13. Volcanoes: Process, Products, Types, Landforms and Distribution
14. Earthquakes: Processes, Causes and Measurement
15. Plate Tectonics and Earthquakes
16. Composition and Structure of Earth’s Interior
17. Artificial Sources to Study Earth’s Interior
18. Natural Sources to Study Earth’s Interior
19. Internal Structure of Earth
20. Chemical Composition and Layering of Earth
21. Weathering: Definition and Types
22. Mass Wasting: Concept, Factors and Types
23. Models of Slope Development: Davis, Penck, King, Wood and Strahler
24. Davis Model of Cycle of Erosion
25. Penck’s Model of Slope Development
26. King’s Model of Slope Development
27. Alan Wood’s Model of Slope Evolution
28. Strahler’s Model of Slope Development
29. Development of Slope
30. Elements of Slope
31. Interruptions to Normal Cycle of Erosion
32. Channel Morphology and Classification
33. Drainage System and Drainage Pattern
34. River Capture or Stream Capture
35. Stream Channel Pattern
36. Fluvial Processes and Landforms: Erosional & Depositional
37. Delta: Definition, Formation and Types
38. Aeolian Processes and Landforms: Erosional & Depositional
39. Desertification: Definition, Problem and Prevention
40. Glacier: Definition, Types and Glaciated Areas
41. Glacial Landforms: Erosional and Depositional
42. Periglacial: Meaning, Processes and Landforms
43. Karst Landforms: Erosional and Depositional
44. Karst Cycle of Erosion
45. Coastal Processes: Waves, Tides, Currents and Winds
46. Coastal Landforms: Erosional and Depositional
47. Rocks: Types, Formation and Rock Cycle
48. Igneous Rocks: Meaning, Types and Formation
49. Sedimentary Rocks: Meaning, Types and Formation
50. Metamorphic Rocks: Types, Formation and Metamorphism
51. Morphometric Analysis of River Basins
52. Soil Erosion: Meaning, Types and Factors
53. Urban Geomorphology: Concept and Significance
54. Hydrogeomorphology: Concept, Fundamentals and Applications
55. Economic Geomorphology: Concept and Significance
56. Geomorphic Hazard- Earthquake: Concept, Causes and Measurement
57. Geomorphic Hazard- Tsunami: Meaning and Causes
58. Geomorphic Hazard- Landslides: Concept, Types and Causes
59. Geomorphic Hazard- Avalanches: Definition, Types and Factors
60. Integrated Coastal Zone Management: Concept, Objectives, Principles and Issues
61. Watershed: Definition, Delineation and Characteristics
62. Watershed Management: Objective, Practice and Monitoring
63. Applied Geomorphology: Concept and Applications