Nature Environment and Pollution Technology

G. Bindu ¹, R. Neelakantan ², Rajesh Reghunath ³

Affiliations
1 State Ground Water Department, Thiruvananthapuram, Kerala, IN
2 Department of Industries and Earth Sciences, Tamil University, Thanjavur, T. N., IN
3 Department of Geology, Kerala University, Thiruvananthapuram, Kerala, IN

Abstract

The use of the drainage morphometric characteristics for the investigations relating to hydrology has been amply discussed in various studies. The realization of its importance has made the analysis of drainage morphometric characteristics studies related to hydrological studies. The morphometric analysis of Chittar River Basin (CRB), a fifth order sub basin of Vamanapuram River on the south west coast, has been studied using Arc Info GIS software. The drainage patterns of the basin are delineated using IRS IC LISS III data and SOI toposheets on 1:25,000 scale as reference. The drainage pattern of the study area is dendritic with stream orders ranging from I to V. The different drainage parameters studied include drainage pattern, stream order, stream number, stream length ratio, relief ratio, bifurcation ratio, constant of channel maintenance, frequency of source head, frequency of confluence points, slope and DEM. The drainage density of the Chittar basin varies from 1 km/km² to > 4 km/km². Stream length ratios for different stream orders vary between 0.30 and 0.64, which are low to moderate and suggest the moderately resistant hard rock terrain. The bifurcation ratio of streams of different order of the basin varies from 3.21 to 5.00. The average bifurcation ratio for the Chittar basin is 3.94, which is near to 4, suggesting some structural control over the development of drainage basin. The relative relief of the basin varies from place to place and most of the basin comes under the category of 30-60 m. At some places relative relief is very high and it suggests rugged topography. It is concluded that Remote Sensing and GIS have been proved to be efficient tools in drainage delineation and updation.

Keywords

Chittar Basin, Morphometric Characteristics, Remote Sensing, GIS.

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Rajesh Reghunath ¹

Affiliations
1 Department of Geology, University of Kerala, Kariavattam Campus, Thiruvananthapuram-695 581, Kerala, IN

Abstract

The natural recharging of groundwater in any watershed is a key parameter on which many other components of the watersheds are depended on. Finding out of natural recharging zones of groundwater and their preservation is a prime requirement for maintaining the socio-ecological equilibrium, but such attempts were not been dealt seriously till now owing to the intricacy involved in it. Here, a simple technique is developed to find out the natural recharging zones of groundwater in a watershed. The depths to water table (below ground level) measured in a systematic network of observation wells just before the starting of the monsoon rainfall and just after the initiation of the monsoon spell (after the heavy downpour of the initial 2-3 weeks) are used to delineate the natural recharging zones. The zones, which act as the areas of natural recharge of groundwater should be conserved and no landscape alterations should be allowed in such zones. The present simple methodology, which is cost effective can be applied to any river basins/watersheds to delineate the natural recharging zones of groundwater.

Keywords

Natural Recharging Sites, Groundwater, Water Table, Mamam River Basin, Watershed.

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Rajesh Reghunath ¹, S. Biju Sekhar ², R. Nithin ², R. B. Binoj Kumar ³

Affiliations
1 Department of Geology, University of Kerala, Kariavattom Campus, Trivandrum-695 581, Kerala, IN
2 Centre for Environment and Development, Trivandrum, Kerala, IN
3 Department of Geology, University of Kerala, Kariavattom Campus, Trivandrum-695 581, Kerala, IS

Abstract

Attappady region in the Palghat district of Kerala is one of the severely degraded areas in the Kerala Western Ghats. Apart from the severe ecological, socio-economic, political and cultural problems, the region faces an acute water scarcity too. By identifying the severe ecological degradation and the consequent sociological problems, a watershed based massive ecorestoration project has been initiated in Attappady by the State government. The present study carried out in this area deals with the identification of groundwater potential zones. The groundwater potential zones of Attappady area generated from this study identifies five zones- very high, high, moderate, low and very low. The groundwater potential map generated in this study by making use of GIS tools will be useful in narrowing down the target areas for ground resistivity surveys in order to pinpoint the prospective well site. The results of this study can be used in the ongoing ecorestoration project at Attappady.

Keywords

Groundwater Potential Zones, Groundwater Prospective Index, Degraded Regions, Western Ghats, Attappady.

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