Hydrogeomorphic Units Research Articles

Delineation and Characterization of Geomorphological Features Studies of Muguru Addahalla Watershed, Mysore and Chamarajanagar Taluks of Southern Part of Karnataka, India

In the present study an attempt has been made to delineate and characterize the different geomorphic units of Muguru Addahalla watershed located in the southern part of Karnataka State, India. The drainage network and topographic elevation contours have been delineated using toposheets. The geological units have been overlaid on the Indian Remote Sensing (IRS)-1D LISS-111 satellite imagery. The study area is basically a drainage-controlled region wherein the fluvio-geomorphological processes dominate on the surface. Based on the interpretation of satellite data, the hydrogeomorphic units like linear ridges, shallow moderate and deeply buried slopes, shallow valley fills and deep valley fills have been demarcated. These zones have been generated as vector layers using GIS and the geological and geomorphological maps of the study area have been compared. This integrated approach demonstrated that the IRS data used in conjunction with geology, drainage and topographic parameters helped in the evaluation of different geomorphological units and their characteristics. These features were also verified based on the field observations. The geomorphological units can be utilized for the management of natural resources.

The development of a classification system for inland aquatic ecosystems in South Africa

A classification system is described that was developed for inland aquatic ecosystems in South Africa, including wetlands. The six-tiered classification system is based on a top-down, hierarchical classification of aquatic ecosystems, following the functionally-oriented hydrogeomorphic (HGM) approach to classification but incorporating structural attributes at the lower levels of the hierarchy. At Level 1, a distinction is made between inland, estuarine and shallow marine systems using the degree of connectivity to the open ocean as the key discriminator. Inland systems are characterised by the complete absence of marine exchange and/or tidal influence. At Level 2, inland systems are grouped according to the most appropriate spatial framework for the particular application. At Level 3, four primary Landscape Units are distinguished (Valley floor, Slope, Plain, Bench) on the basis of the topographic position within which a particular inland aquatic ecosystem is situated, in recognition of the influence that the landscape setting has over hydrological and hydrodynamic processes acting within an aquatic ecosystem. Level 4 identifies HGM Units, defined primarily according to landform, hydrological characteristics and hydrodynamics. The following primary HGM Units (or HGM Types), which represent the main units of analysis for the classification system, are distinguished at Level 4A: (1) River; (2) Floodplain Wetland; (3) Channelled Valley-Bottom Wetland; (4) Unchannelled Valley-Bottom Wetland; (5) Depression; (6) Seep; (7) Wetland Flat. Secondary discriminators are applied at Level 5 to classify the hydrological regime of an HGM Unit, and Descriptors at Level 6 to categorise a range of biophysical attributes. The HGM Unit at Level 4 and the Hydrological Regime at Level 5 together constitute a Functional Unit, which represents the focal point of the classification system. The utility of the classification system is ultimately dependent on the level to which ecosystem units are classified, which is in turn constrained by the type and extent of information available.

Study of Groundwater Prospects of the Crystalline Rocks in Purulia District, West Bengal, India Using Remote Sensing Data

Visual interpretation of satellite imageries of IRS P6 LISS III standard false colour composite (FCC) has been made for lineament and hydrogeomorphological analyses. Analyses of lineament density, lineament intersection density, spatial dis- tribution of hydrogeomorphic units and lithology have been carried out for the study of groundwater prospects in crystalline rocks. Each theme is assigned a weightage depending on its influence on the storage and movement of groundwater and each unit in every theme map is assigned a knowledge based ranking depending on its significance to groundwater occurrence. The cu- mulative scores have been worked out and the scored pattern has been contoured in preparing the final potential map using Surfer software and classified into five groundwater prospect categories which are further justified by hydrological studies.

Regional prediction of wetland degradation in South Africa

Wetland assessments in South Africa continue to be undertaken at the scale of individual wetlands, while ultimately a landscape assessment is required for broader regional planning. The aim of this research was to develop probability models of degradation per wetland type using landscape-scale predictor variables. Condition data for a total of 463 seep, floodplain and valley bottom (channelled and unchannelled) hydrogeomorphic (HGM) units was combined with data for 21 potential explanatory variables for land cover, infrastructure and catchment physiography. Multiple logistic regression models to estimate the probability of degradation per HGM type were investigated at three different spatial levels (1,000 m buffer radius; 100 and 1,000 km2 scales). Models at the intermediate scale were most useful and only these are reported. Percent natural vegetation, road density, population density and altitude, together with anthropogenic land use (cultivation and forestry plantation area) were important predictors of wetland condition, and differed per HGM type. Regional patterns of degradation within quaternary catchments in KwaZulu-Natal were dissimilar for each HGM type. There is potential to refine and extend the models for application at a national level, and to predict actual condition scores using ordinal logistic regression based on larger datasets.

Evaluation of natural resource potential in semi-arid micro-watershed, eastern Rajasthan, using remote sensing and geographic information system

The natural resources are considered more efficient and appropriate for necessary survey and investigation for the assessment, subsequent planning and implementation of various developmental programmes. Hence, it is necessary to increase the land and water resources levels for future demands. Morphometric, land use/land cover and hydrogeomorphic analyses have been carried out by visual interpretation method of remote sensing data of IRS, 1D-LISS III and IRS, P6-LISS III, and FCCs of band combination 2, 3 and 4. The interpreted data is supplemented as well as cross checked by field visits. The remote sensing and GIS tool could be helpful in getting the precise and valuable spatial information in understanding the present scenario contemplating with the past data and predicting the future trends. Morphometric analysis was done to determine the drainage characteristics of Bankukara watershed. The drainage pattern of the study area is predominantly dendritic to sub-dendritic in nature; however, locally structurally controlled drainage pattern is also seen. The development of stream segments is affected by slope and local relief. The bifurcation ratio indicates that the drainage pattern is structurally controlled. The land use/land cover change detection for 2001 and 2005 showed an increase in uncultivated land by 1.37%, dense forest by 0.17%, wasteland by 1.46% and rock quarry by 0.10%. There has been a decrease in the area under cultivated land by 1.99%, open forest by 0.12%, open scrub by 0.54% and water body by 0.40%. Hydrogeomorphic units identified through visual interpretation of FCC include alluvial plain, valley fills, plateau, buried pediment, pediments and intermontane. Based on land use/land cover change detection and hydrogeomorphological mapping, the Bankukara watershed has qualitatively been categorized into four groundwater potential zones, viz. good to very good, moderate to good, poor to moderate and very poor to poor.

A rapid assessment method for coupling anthropogenic stressors and wetland ecological condition

South Africa faces growing impacts on wetlands and limited resources for conducting assessments. In response, a method for the rapid assessment of ecological condition based on the impacts of human stressors on hydrogeomorphic processes and vegetation responses was developed. The rapid assessment method, referred to as WET-Health, divides wetlands into hydrogeomorphic (HGM) units that are assessed individually. Results are then combined into a composite health score for the wetland system being evaluated. Deviation from the natural reference condition is examined for three separate but interlinked components of ecosystem health: hydrology, geomorphology and vegetation. The spatial extent of the HGM unit affected by a human impact is estimated and the intensity of the impact in the affected area is scored on a scale of 0 (no impact) to 10 (complete transformation) based on pre-determined indicators that are rated using clear scoring guidelines. Extent and intensity are combined to give an index of the level of departure from the natural reference condition. An assessment is also made in each module of the likely trajectory of change of the wetland. This paper describes the method in order to reflect on the central approach and highlight its heuristic and hypothesis generating value.

Hierarchical spatial organization and prioritization of wetlands: a conceptual model for wetland rehabilitation in South Africa

Wetland rehabilitation planning needs to take into account many different aspects of the wetland and its context. In South Africa, much emphasis is placed on the delivery of ecosystem services, poverty relief and skills development for those involved in labour-intensive rehabilitation measures. A framework is presented that facilitates decision-making with regards to wetland rehabilitation planning. This starts with prioritizing which wetlands need attention within a catchment. This is followed by decisions regarding which rehabilitation measures would be effective in improving certain ecosystem services based upon the aims of rehabilitation and the social context of the surrounding catchment. The functional unit that is most suitable to work with for rehabilitation is the Hydrogeomorphic (HGM) Unit, defined as a section of a wetland with more or less uniform hydrological and geomorphological characteristics. An individual wetland may comprise several HGM units, and a HGM Unit itself can be sub-divided into several smaller habitat or vegetation units. Different rehabilitation measures have been identified which are appropriate for the different scales in this spatial framework. Two case studies are presented as examples of how this spatial framework impacts upon the decisions made by the rehabilitation practitioner.

Perspect and assessment of groundwater resources using remote sensing techniques in and around Choral river basin, Indore and Khargone districts, M.P.

The study area around Choral river basin in the Narmada valley region, forms a part of Indore and Khargone districts of Madhya Pradesh. The geological, geomorphologic, lineament, hydrogeomorphic and groundwater potential zone maps of the study area have been prepared using IRS IC LISS III FCC imagery on 1:50,000 scale. Various litho-units, different land-forms, lineament fabric and hydro-geomorphic units have been worked out by visual interpretation methods and frequent field checks. The integrated hydro-geomorphological map of the study area reveals that the groundwater potential in denudation landforms such as buried pediplains, plateaus, denudational and residual hills is moderate-to-poor. On the other hand, the groundwater occurrence in structural landforms like structural hills, lineaments/faults and narrow gorges is likely to be good to moderate and the depositional landforms namely alluvial plains, valley-fills and meandering-channels favour the accumulation of sub-surface water and, therefore, may be considered as good recharge zones. From the point of view of groundwater occurrence, various hydro-geomorphic units have been classified as high, moderate and low potential zones.

Land Use in Korean Tidal Wetlands: Impacts and Management Strategies

The coastal landscapes in southwestern Korea include a diverse array of tidal wetlands and salt marshes. These coastal zones link the ecological functions of marine tidal wetlands and freshwater ecosystems with terrestrial ecosystems. They are rich in biological diversity and play important roles in sustaining ecological health and processing environmental pollutants. Korean tidal wetlands are particularly important as nurseries for economically important fishes and habitats for migratory birds. Diking, draining, tourism, and conversion to agricultural and urban uses have adversely affected Korean tidal wetlands. Recent large development projects have contributed to further losses. Environmental impact assessments conducted for projects affecting tidal wetlands and their surrounding landscapes should be customized for application to these special settings. Adequate environmental impact assessments will include classification of hydrogeomorphic units and consideration of their responses to biological and environmental stressors. As is true worldwide, Korean laws and regulations are changing to be more favorable to the conservation and protection of tidal wetlands. More public education needs to be done at the local level to build support for tidal wetland conservation. Some key public education points include the role of tidal wetlands in maintaining healthy fish populations and reducing impacts of nonpoint source pollution. There is also a need to develop procedures for integrating economic and environmental objectives within the overall context of sustainable management and land uses.

Quantitative morphodynamic typology of rivers: a methodological study based on the French Upper Rhine basin

AbstractThis study sought to establish a quantitative functional hydrogeomorphological typology of river reference types in the French Upper Rhine basin that would meet the requirements of the European Water Framework Directive, defined in terms of hydromorphological quality and prospects for river restoration. Four ecoregions (i.e. hydrogeomorphic units) were delineated by expert opinion and validated by independent variables (i.e. 1·5‐year peak discharge, comparison of 10‐year daily flow and low flow, valley bottom morphology and specific stream power). A data set of 31 quantitative and qualitative variables for 187 field sites was established and analysed. Agglomerative hierarchical clustering (AHC) of the quantitative variables and principal component analysis (PCA) provided hierarchy and grouping of variables. Multiple correspondence analysis (MCA) confirmed these results, discriminating sites into seven groups, but did not lead to a functional typology due to important overlapping between groups and variability within groups. A definitive quantitative typology was obtained through AHC and discriminant analysis with cross‐validation computed separately in each ecoregion. Results for two ecoregions, ‘marly calcareous loess‐covered hills’ and ‘crystalline Vosges mountains’, are given as examples. Finally, the classification of the sites is extended to the whole river network by river sectorization, each homogeneous river section being classified to one category on the basis of the preceding classification of sites. Methodological implications regarding river classification are also given. Copyright © 2007 John Wiley & Sons, Ltd.

Impact of land use on vegetation composition, diversity, and selected soil properties of wetlands in the southern Drakensberg mountains, South Africa

Wetlands provide the ecosystem services of enhancing water quality, attenuating floods, sequestrating carbon and supporting biodiversity. In southern Africa, the pattern and intensity of land use is influenced by whether land tenure is public (state), private (individual ownership), or communal (shared agricultural and grazing resources). The influence of land tenure and its associated use on service provision was compared for communal tenure (grazing, maize production), wildlife conservation, and commercial agriculture (grazing, planted pastures) in the southern Drakensberg. Ordination analyses revealed that oxbow marshes, hill slope seepages and hygrophilous grasslands, the main hydro-geomorphic units, supported distinct plant communities that differed in their response to land use because of wetness or slope. Oxbows, uncultivated because of wetness, were inherently species poor with few exotics. Composition of hill slope seepages, uncultivated because of saturated slopes, varied among tenure types most likely in relation to grazing pressure. Seepages were threatened by the exotic invasive Rubus cuneifolius. Eighty-five percent of hygrophilous grassland had been cultivated by 1953, most of which was subsequently abandoned to secondary grassland. Primary hygrophilous grassland and hill slope seepages were the main repository for indigenous plant diversity, while communal maize fields supported a diverse mixture of mainly exotic species. Soil carbon concentrations decreased from oxbows to pastures, seepages, primary hygrophilous grassland, secondary grassland, and maize on former grassland (7.0, 4.1, 4.0, 3.5, 2.4, and 1.7%, respectively). The pattern for total soil nitrogen and sulphur were the same. Cultivation of hygrophilous grassland was estimated to have reduced soil carbon stocks to 69% of pre-settlement levels by 1953 (∼150 years BP). Stocks then increased by 8% to 2001 following crop abandonment. Cultivation has impaired water quality enhancement and flood attenuation because of greater amounts of bare ground and shorter vegetation. Further improvement of ecosystem services will depend on the influence of socio-economic factors on communal cropping.

Prospecting ground water resources using RS-GIS—A case study from arid western rajasthan of India

In arid regions, inherent climatic conditions and adverse terrain condition pose perpetual shortage of water. The dominant aeolian topography conceals older geological formations making it difficult to infer prospects of ground water and tapping the same. A ground water prospect map has been prepared for a part of Jodhpur district in western Rajasthan through integrated analysis of four major controlling factors: geology, geomorphology, structure and hydrology. Through visual interpretation of satellite data and using Geographical Information System, twenty-five hydro-geomorphic units (prospect units) have been delineated and mapped. Potential of each prospect unit have been discussed in reference to hydro-geomorphic units, their influence and well inventory like well yield, water table level and quality of drinking water. 34 % of the area was classified to have high groundwater potential and 5.8 % area was classified into low potential categories. Most of the area (60.2 %) is of moderate ground water potential.

Hydrogeomorphological Controls on Groundwater Quality in the Rattaphum Catchment (Songkhla Lake Basin), Thailand

The Rattaphum Catchment comprises four major hydrogeomorphic units: mountains, footslopes, plains and inland swamps around a lake system. The area accommodates three main agro-ecosystems: vegetable, rubber and fruits. During the high-rainfall period, groundwater levels rise near to the soil surface in all agro-ecosystems. The high water levels remain for 3–4 months in the coastal plain, while in other areas the groundwater level fluctuates according to the intensity of rainfall events during the 2–3 months of the rainy season.

Identification of groundwater prospective zones using irs-id liss iii and pump test methods

The role of hydrogeomorphological units and lineaments in the storage of groundwater from the Muvattupuzha river basin has been investigated using IRS ID LISS III data. Other than the usual water bodies such as river course, reservoirs and ponds, the major hydrogeomorphological units identified in this basin in the descending order of their groundwater potential are: valley fills, moderately dissected plateau, pediments, residual mounts, residual mount complex, linear ridges, residual hills and structural hills. Majority of the lineaments trends in NW-SE and WNW-ESE directions. Even though the eastern part of the basin is characterised by moderate to high lineament density, the above area is found to be poor to moderate groundwater prospect zone because of high gradient and structural hills. The pump test analyses of dug wells from different hydrogeomorphic units also confirm that valley fills are the most promising unit for groundwater prospecting than the rest.

Influence of rock types and structures in the development of drainage network in hard rock area

Remote sensing techniques has proved to be an extremely useful tool in morphometric analysis and groundwater studies. Remote sensing techniques with an emphasis on lineament identifications can play a great role in groundwater prospecting in semi-arid hard rock areas of Purulia district. In the present study, morphometric analysis using remote sensing technique has been carried out in parts of Baghmundi block, Purulia district, West Bengal. The parameters worked out include Bifurcation ratio (Rb), Stream length (Lu), Form factor (Rc), Circulatory ratio (Rc), and Drainage density (D). The morphometric analysis suggests that fractured, resistant, permeable rocks cover the area, the drainage network not so affected by tectonic disturbances. Using satellite imageries of two dates of IRS, different hydrogeomorphological units have been delineated. Among different hydrogeomorphic units (i) very shallow weathered pediment and (ii) Structural hills/ residual hills/inselbergs have very poor ground water prospects, while moderately weathered pediplains and valley fills are good prospective zones for groundwater exploration.

Functional Assessment for Restoration of Intertidal Sandy and Muddy Flat Ecosystems

The restoration of the wetland ecosystems is an essential problem in the world, however, the evaluation technique for the functions of ecosystems, especially in the intertidal wetlands, has not been established still in spite of the ecosystems adjoining with the human life. The Functions of a wetland tend to roughly correspond with characteristics of both the water and sediments of the wetland. In this study, the 13 intertidal sandy and muddy flat wetlands were selected from Hokkaido to Okinawa, and the indicators for water and sediments were investigated as a first step of the functional ecosystem assessment in Japan. The classification for traditional landform subclass, i. e. fore-beach, estuary and lagoon, was unclearly changeable, and it often did not agree with the functional classification. In the intertidal sandy and muddy flat wetlands in Japan, the subclass fo HGM Approach should be set corresponding to the characteristics of influent water and sediments, and it was considered that the ecosystem evaluation should be carried out in each Hydrogeomorphic Unit classified at smaller-scale than the original HGM Approach in U.S.

Hydrogeomorphological and groundwater prospects of the Pageru river basin by using remote sensing data

Hydrogeomorphology and lineament studies have been completed by using satellite data for the Pageru river basin, Cuddapah district, Andhra Pradesh, India through visual interpretation of IRS-1B-LISS II FCC (57J/6, J/7, J/10 and J/11) on a 1:50,000 scale. The area has been visually interpreted to delineate various hydrogeomorphic units and lineaments for the development of groundwater. From these studies, various geomorphic units were classified as favourable, moderately favourable and poor zones of groundwater. The integration of geomorphology and lineament studies reveal that shallow groundwater occurrence is controlled by geomorphological characteristics whereas faults/fractures control the yield of groundwater at intermediate depths.

Evaluation of multispectral, fine scale digital imagery as a tool for mapping stream morphology

Multispectral digital imagery acquired from Soda Butte and Cache Creeks, Montana and Wyoming was used in conjunction with field data to classify and map hydrogeomorphic stream units on four stream reaches. The morphologic units that were field mapped were eddy drop zones, glides, low gradient riffles, high gradient riffles, lateral scour pools, attached bars, detached bars, and large woody debris. Unsupervised and supervised classifications of the imagery were used to develop a Maximum Joint Probability classification and an Alternative Joint Probability classification of the stream reaches. The Maximum Joint Probability classification allowed only one of the image classes to represent each hydrogeomorphic unit on the field map and resulted in relatively low overall accuracies for identification of these units of 10% to 50%. The Alternative Joint Probability classification allowed each image class to represent any geomorphic unit where the probability of a correct classification was greater than random. In this technique, two or three image classes were assigned to represent each hydrogeomorphic unit, resulting in higher overall accuracies of 28% to 80%. Accurate classification of hydrogeomorphic units was hampered by poor rectification of imagery with the field maps because of inadequate ground control points. In general, the largest hydrogeomorphic units were most accurately classified, whereas units that were small in area or spatially linear were least likely to be accurately classified. The results of this study demonstrated that multispectral digital imagery has the potential to be a useful tool for mapping hydrogeomorphic stream units at fine scales. Imagery to be an effective tool, however, careful measures such as accurate documentation of ground control points must be taken to ensure accurate rectification of the imagery with field maps.

Carbon, nitrogen and phosphorus cycling in river marginal wetlands; a model examination of landscape geochemical flows.

The importance of landscape geochemical flows was investigated using a dynamic model simulating carbon, nitrogen and phosphorus cycling in riverine wetlands, which has been described in a previous paper. The hydro-geomorphic unit (HGMU) concept was incor- porated in the model by defining a separate, complete unit-model for each unit (HGMU) within the wetland. These unit-models were connected by defining the flows of nitrogen and phos- phorus between them. These flows, also called landscape geochemical flows, usually consist of flows of water containing N and P. The model was applied to a site at Kismeldon Meadows, in south-western England. This site consists of two units, a slope and a floodplain, separated by a ditch, which catches most of the run off and shallow groundwater flows from the slope. Only an estimated 1% of the N and P that leaves the slope unit in the water outflow reaches the floodplain unit; the rest is caught in the system of ditches, which prevent the geochemical flows taking their natural course. To examine the influence of this system of ditches, the model was run for the same site, but without the ditches. This is comparable to a situation of a restored site, where run off and shallow groundwater flows containing nutrients, can freely get from the slope to the floodplain. The computer simulation experiment reconnecting the slope and floodplain showed that this (1) increased the nutrient input into the floodplain, causing a higher biomass production, and (2) increased the wetness of the floodplain, causing slower decomposition, which together (3) led to a faster soil organic matter accumulation in the floodplain. Nutrient inflows became relatively more important compared to atmospheric deposition, especially for phosphorus. By connecting the slope and the floodplain more nitrogen and less phosphorus flowed into the river.

Groundwater assessment through hydrogeomorphological and geophysical survey — A case study in Godavari sub-watershed, Giridih, Bihar

Groundwater assessment has been carried out through hydrogeomorphological and geophysical survey. Remotely sensed data has been used to delineate the hydrogeomorphological units. Each hydrogeomorphological unit has been further sub-divided based on the tone, texture and pattern. These units its have been categorised based on depth of weathering, local geomorphological association, recharge characteristics etc. The top layer resistivity of hydrogeomorphological units has been analysed by electrical resistivity method. Correlation between different sub-units of same hydrogeomorphic unit and top soil resistivity has been attempted. The correlation and integration of resistivity map with geomorphological map were carried out through. ‘GRAM’ Geographic information System, This has helped in better understanding the surface resistivity pattern.