30 Hydrogeomorphology

Dr. Manju Chillar

    Pre-requisites

Drainage Basin, Water Cycle

  Objectives

1. Meaning of the term Hydrogeomorphology

2.Fundamentals of Hydrogeomorphology

3.Hydrological Cycle and Water Budget

4.Application of Remote Sensing and Geographic Information Systems in Hydrogeomorphology

5.Application of Hydrogeomorphology

6.Future of Hydrogeomorphology as Geosciences

Keywords

Hydrogeomorphology, Geosciences, Catchment Scale, Hydrological Cycle, Water Budget

    Introduction

Resources are essential elements for the sustainability of human beings. Among all the resources, water and land are among the most important resources. Hydrogeomorphology deals with both of these resources. Hydrogeomorphology is a new field in geosciences that has emerged to study the linkages between water processes and landforms. It is a combination of three different terms:

Hydro : refers to water including both surface and underground water

Geo : refers to the ground and the landforms

Morphology : refers to the surface characteristics of the landforms

Hydrogeomorphology studies to major aspects:

Ø  Affects of moving water to hill slopes, rivers and landscapes on geomorphic processes and geomorphic forms

Ø  Affects of geomorphic form on the spatial and temporal distribution of shallow groundwater

So hydrogeomorphology is an inter-disciplinary science that studies the link between two important branches of geosciences i.e. hydrology and geomorphology. Other than hydrology and geomorphology, the concepts of hydrogeomorphology are also largely derived from the different branches of geosciences like geology, remote sensing, climatology and natural hazards.

To study hydrogeomorphology, it is important to understand the difference between three branches of geosciences i.e. hydrogeomorphology, geology, hydrology, and Geomorphology

Hydrogeomorphology, geology, hydrology and geomorphology all are different branches of geosciences and covers different subject matter but often get confused. Geology is that branch of geosciences that studies materials of the earth along with the processes that are working upon them. Hydrology studies the occurrence, distribution, movement and relationship of water with all the aspects of environment it interacts with. Geomorphology is the subfield of geology and studies the structure and evolution of the surface of earth. It deals with origin and changing structure of earth’s landforms.

History of Hydrogeomorphology

In 1973 Scheidegger used the term ‘hydrogeomorphology’ for the first time in a science article under the Journal of Hydrology. He defined hydrogeomorphology as the study of shapes caused by water activity. He considered water as the most important shaping agent of the landforms. In 1988, Richards used this term again after the gap of 15 years to emphasis on the role of hydrogeomorphological studies in understanding the prediction scenarios for the river evolution at the hydrographic basin scale. Okunishi also made a research on the term “hydrogeomorphology” in the year 1994, which further strengthen the growth of hydrogeomorphology as an important branch of geosciences. He defined hydrogeomorphology as the study of the interactions between hydrological processes and geomorphological ones.

In recent years researchers of hydrogeomorphology are emphasising more on explaining the landforms i.e. their functions and the process through which the landforms have evolved along with the hydrological conditions. In 2010 Malavoi and Bravard stated the use of hydrogeomorphology in France for demarcating the flooded areas on the basis of topographic and geomorphic characteristics of the bottom valley.

In 2012 Santos et al. defined hydrogeomorphology as a science that not only tries to understand the way in which the hydrological processes contribute to the moulding and the evolution of the landscape but also the way in which the landforms influence or control the hydrological processes at different temporal and spatial scales. The surface and ground water influences the formation, development and characteristics of the landforms and in its turn, the landforms affect the intensity, the magnitude and the duration of the hydrological process.

To establish the link between hydrology and geomorphology under hydrogeomorphology,

Santos et al. (2012) has given three models. These models are:

Ø The first model suggests a superposition of the common areas of both hydrology and geomorphology to avoid any interface between them. This clearly means that both the sciences i.e. hydrology and geomorphology will uses similar methods, but there will be no interaction between them.

   Ø The second model suggests the crossing between hydrology and geomorphology, which thus becomes the common object for both sciences. This model was based on the statement given by Okunishi (1994) that hydrogeomorphology is “a little hydrology and a little geomorphology.”

Ø The third model considers hydrogeomorphology as an independent branch of science which incorporates both its own characteristics and elements from hydrology and geomorphology.

Fundamentals of Hydrogeomorphology

The important fundamentals of hydrogeomorphological studies are given below:

Mechanism and Process: Mechanism gives the explanation by describing the physical and chemical effects while the process is the simultaneous operation of a set of specific mechanisms over a specific period of time. In hydrogeomorphological studies the landforms are studied with reference to groundwater conditions of the area. So while studying the mechanism and process in Hydrogeomorphology, the morphological, climatic and hydrological criteria’s are considered. The study of mechanism and the process involved helps to give explanation behind morphology and distribution of landforms

Basic tools required: To carry out a study in hydrogeomorphology it is very important to first design a geographic database including both spatial and non spatial data requirements with their sources. The most important requirement for the studies in hydrogeomorphology is maps. This includes the topographical maps, geological maps of the area, soil map, rainfall and climate distribution map, geomorphological map, population density map and groundwater fluctuation map. In India, the sources for these maps are various government agencies and publication like:

Survey of India for Toposheet Maps

National Bureau of Census for Population Density Map

Geological Survey of India for Geological Maps

Indian Meteorological Division for Climate and Rainfall Distribution data Maps

National Bureau of Soil Survey and Landuse Planning, for Soil Maps

    All India Soil and Land Use Bureau for Landuse and Land Cover Maps

Along with the maps it also important to update the data through satellite data collected from various national and international remote sensing agencies like Indian institute of Remote Sensing Agency (IIRS), Dehradoon, National Remote Sensing Agency (NRSA), Hyderabad.

Properties of Earth Materials: Hydrogeomorpholgists studies the properties of earth materials to get better understanding of mechanism and process behind the geomorphic features. They emphasis on the properties of the parent material influencing the formation and development of landforms along with the hydrological conditions. Type of rock, weathered material, soil, superficial deposits, shear strength, porosity and mineral composition are some of the important properties that hydrogeomorphologists studies during their research.

Spatial Scales of Hydrology: Hydrogeomorphology not only studies the effect of hydrological processes on the geological processes but also analyses the effect of landforms on the hydrology of an area. Thus the study of scaling effects becomes essential. The spatial scales in hydrology can be distinguished into three types:

Local Scale: On local scale the parameters like slope angle directly influences the water flow path geometries, flow velocity and quantity.

Hill Slope Scale: In hill slope scale is characterised by its runoff production. The soil properties influence the runoff production in the hill slope scale.

Catchment Scale: In catchment scale morphometry of the basin influences the runoff production.

Dimensions of Hydrological Units: Hydrogeomorphology studies the role of dimension of hydrological units in defining the size and dimensions of the geological landforms. In India Watersheds are delineated at various levels on the basis of the drainage network. Watershed can be defined as an area of land that includes common set of streams and river draining their water into single larger water body. Water in watershed can come from any of the sources of water from precipitation, in form of rain or snow or as groundwater or surface runoff. The size of the watershed depends on size of the stream, river, the point of interception of stream or river, the drainage density and its distribution.

Hydrological Cycle and Water Budget

Hydrology being an important part of hydrogeomorphology it becomes important for hydrogeomorpholgist to study the hydrological cycle, water balance and water budget for their research studies. Circulation of water into different forms between various spheres of earth surface is called hydrological cycle. Hydrological cycle recycles earth’s water. The hydrological cycle includes inflow, outflow and storage of water at different levels. The inflows add the water into the system while outflow subtracts the water. Storage helps in the retention of water in the system.

Water budget studies the water availability. It includes the balance between the inflows and outflows of the water. In water or hydrologic budget the inputs are derived from precipitation, surface water inflow and groundwater inflow. Output factors include evaporation, combined surface and groundwater outflow and transpiration.

Application of Remote Sensing and Geographic Information Systems in Hydrogeomorphology

To get the proper understanding of hydrogeomorphology, it is essential to collect geological, structural and hydrological data of region. Collection of hydrological data i.e. assessing the data of surface and sub-surface water resources requires huge time and manpower. GIS and remote sensing are the platforms through which the all the required data can be collected with better accuracy and time. Remote Sensing and GIS carries great importance in hydrogeomorphological studies.

Before looking at the application of remote sensing and Geographic Information System (GIS) in hydrogeomorphology it is important to understand the concept of remote sensing and GIS.

In early 1960s the term remote sensing was first used for the first time. Remote sensing can be defined as the process of acquiring information through recording devices called sensors about the objects and phenomena without getting in physical contact with them. In remote sensing the data acquisition is done through different stages.

The stages involved in remote sensing for data collection are given below:

Ø  Source of energy

    Ø  Transmission of energy from the source to the earth surface

Ø  Interaction of energy with earth’s surface features

Ø  Propagation of reflected energy/emitted energy through atmosphers

Ø  Detection of reflected /emitted energy by the sensor

Ø  Conversion of energy recorded into digital /photographic form

Ø  Extraction of the information from the data generated

Ø  Conversion of information into map/tabular form

Satellite imageries and aerial photographs are the outputs of the process of remote sensing passing all the above mentioned stages. The interpretation of the satellite images and aerial photographs generated by remote sensing are made through the different elements of visual interpretations. The important elements are tone, texture, size, shape, shadow, pattern and association. In the study of hydrogeomorphology the same elements of visual interpretation are used to get the information through the interpretation of the images generated by remote sensing of the landforms and the regions covering the water resources.

Geographic Information System (GIS) is a tool of digitally capturing, managing, analyzing and displaying geographic data using the computer hardware and software. Maps, computer hardware and software, information, procedures and people are the important components of GIS. GIS is an important tool for geographic studies because it analysis and answers real world problems. It makes dynamic maps and displays detailed information about the features in the maps. It not only displays but also studies and establish relationship between the features. The application of GIS can be seen in studying the relationships, patterns and trends of various spatial and non spatial elements of the earth surface. GIS contributes vastly in the study of Land use/land cover studies along with the studies associated with water and soil resources.

Over the years due to rapid increase in population, rapid urbanisation and industrialisation along with failure in monsoons has restricted the availability of surface water. Limited availability of surface water has increased the burden on groundwater resources. This has resulted into higher rates of groundwater withdrawal which further resulting in depletion of groundwater at alarming rates. For the management and conservation the study of groundwater resources is very important. Satellite remote sensing has made it easy to study the spatial distribution of ground water prospects on the bases of geomorphology and other associated features. Satellite remote sensing is also a useful technique for groundwater exploration along with delineating the hydrogeomorphological units. Ground water accumulation, infiltration and movement largely depend on the factors like drainage, geomorphology, and slope of the terrain, vegetation, soil and depth of weathering. All these factors can be easily studied using remote sensing at various levels.

Remote sensing not only studies the hydrological aspects but it also an effective tool for geological, structural, geomorphologic analysis and their mapping due to its synoptic, multi spectral and multi-temporal capabilities. Geologists largely depend on satellite imageries to collect the data on various lithological units.

The important advantages of remote sensing in hydrogeomorphological studies are as follows:

Ø  Remote sensing has access to large areas and even in inaccessible areas.

Ø  The aerial photographs and satellite imageries provide detailed information about the uppermost layer of the earth surface which is essential for the hydrogeomorphological studies.

Ø Digital enhancement of satellite imageries improves the level of information useful in study of hydrogeomorphology.

Ø Data generated by remote sensing provide more accurate and spatial information in comparison to the hydrogeological surveys.

Ø  Through remote sensing hydrogeomorphological mapping of a terrain and analysis of their processes can be done easily.

Ø  This will further help in soil resource mapping, groundwater potential zones demarcation, landscape ecological planning, hazard mapping and their environmental applications.

Ø  The application of geomorphologic mapping using remote sensing can also be seen in land use planning and water resource management.

The IRS-1C and 1D data of WiFS, LISS-III and PAN sensors are highly useful for geological mapping. The WiFS camera gives the synoptic coverage of large areas and thus is useful for the regional scale mapping and understanding. The finer geological features like the traces of bedding and minor joints can be easily are identified through panchromatic data. The panchromatic data provides detailed mapping while the multispectral LISS-III gives semi detailed mapping.

Along with remote sensing, in recent years several techniques have been developed in the field of Geographic Information System (GIS) through which hydrogeomorphologic studies can be conducted. In recent years GIS has emerged as a powerful tool in analysing the various aspects of groundwater occurrence. Groundwater resource of any area is largely controlled by the factors like lithology, structure, geomorphology, slope, drainage and landuse/land pattern. All these factors can be studied and analyzed as thematic layers using Geographic Information System (GIS). This makes it easy to delineate the groundwater prospect and deficit zones.

The main advantages of GIS in hydrogeomorphological studies are as follows:

Ø  Large volume of data can analysed and integrated using GIS.

Ø  Manipulates and analysis the individual layer of spatial data.

Ø  Rapid, accurate and cost effective tool

Ø  GIS is a powerful tool for the generation of hydrogeomorphological mapping.

Application of Hydrogeomorphology

The application of hydrogeomorphology can be seen in planning and management of various activities on the earth surface. Some of the important applications of hydrogeomorphology are as follows:

ØThe accurate, detailed, timely and reliable data on the extent, location and quality of land along with water resources and climatic characteristics helps resource planners in agricultural landuse.

 Data on land potential and conservation requirements through the hydrogeomorphological studies helps in improving the quality of land.

ØHydrogeomorphological studies are found helpful by environmentalists in identifying hazards and studying climate change.

Ø Geologist have found it useful in examining role of surface and subsurface flow regimes and flow paths on fluvial erosion and mass wasting.

Ø Ecologists found it useful to describe the linked water and geomorphic conditions that define habitats in wetlands, rivers and other environment.

ØWatershed management depend on the collection and management of information on physical relationship between vegetation, soil and water resources, which can easily be done by hydrogeomorphological studies.

Future of Hydrogeomorphology as Geosciences

Over the years the relationship between physical and human environment is taking new turns and shape. The need for the new subfield called hydrogeomorphology stems from the emergence of various challenges resulted from growing human population combined with its effects on environmental and water resource systems. Transformation in hydrological cycle, water use, land use and climate is result of this change in man – environment relationship. In today’s era hydrogeomorphological studies are great option to manage and control the environmental problems. In recent years hydrogeomorphology has become an important branch of geosciences to tackle natural hazard impact, environmental auditing, resource assessment and impact assessment. To deal with the new challenges, hydrogeomorphology has developed close relationship with various fields like ecology, soil science and pedogeomorphology.

The growth in the importance of hydrogeomorpholgy as a geosciences can be seen with the fact that now the world organisations like UNDP and World Bank have added a clause of understanding the hydrogeomorpholgy the area before starting any development project into it. Emphasis has been made by these organisations to have detailed knowledge of landforms, hydrogeology materials and earth surface processes to be utilized or the remedial work, planning framework and land zoning plans. Thus it can be said that the hydrogeomorphological knowledge is now being utilized in planning and development of earth as a whole. This shows the growth in status and responsibility of hydrogeomorpholgy in recent years as an important field of geosciences.

References

• Babar. (2005) “Hydrogeomorphology : Fundamentals, Applications and Techniques.” New India Publishing Agency., New Delhi, India.
• Teixeira, J., et.al. (2008). “Integrated Approach of Hydrogeomorphology and GIS Mapping to the evaluation of Ground Water Resources: An example from the Hydromineral System of Caldas Da Cavaca, Nw Portugal.” In : The 33rd International Geological Congress, General Symposium: Hydrogeology, Oslo (Norway), Scientific Publishers (India), Jodhpur, pp. 227-249.
• Vogel,M.R. (2011). “Hydromorphology.” Journal of Water Resources Planning and Management, pp.147-149
• Teixeira, j., et.al (2013) “Hydrogeomorphological mapping as a tool in groundwater exploration.” Journal of Maps., Vol. 9, 2. pp. 263 –273.
• Grigorie., Stefania. (2014) “The Concept of Hydrogeomorphology Reflected in Scientific
• Literature.”Academic Journal Article for Geopolitics, History and International Relations, Vol.6,1.
• NCERT Online Textbook., “Introduction to Remote Sensing.” Practical Work in Geography., Class XI., Chapter 7.
• http://all-geo.org/highlyallochthonous/2010/11/what-do-you-mean-by-hydrogeomorphic-processes-some-thoughts-following-my-gsa-session-on-the-topic/
• http://shodhganga.inflibnet.ac.in/bitstream/10603/36421/7/chapter%204.pdf