Scholarly article on topic 'Water Resource Management in a Hard Rock Terrain- A Case Study of Jharkhand State, India'

Water Resource Management in a Hard Rock Terrain- A Case Study of Jharkhand State, India Academic research paper on "Earth and related environmental sciences"

CC BY-NC-ND
0
0
Share paper
Academic journal
APCBEE Procedia
Keywords
{"Secondary porosity" / Geohydrology / Aquifer / "Water resource Management"}

Abstract of research paper on Earth and related environmental sciences, author of scientific article — S.P. Singh, B. Singh

Abstract Water is a precious natural resource. The major portion of Jharkhand state stands on hard rocks which lack primary porosity. The water bearing capacity of these rocks depends on their ability to develop secondary porosity, Rapid Industrialisation & Urbanisation have increased the demand of water in all spheres. Therefore, the conservation & efficient water resource management is essential. The paper is mainly confined to outline the Geology, geohydrology, aquifer characteristics, quality of water etc and suggests measures for water resource management in Jharkhand.

Academic research paper on topic "Water Resource Management in a Hard Rock Terrain- A Case Study of Jharkhand State, India"

Available online at www.sciencedirect.com

SciVerse ScienceDirect

APCBEE Procedía 1 (2012) 245 - 251

ICESD 2012: 5-7 January 2012, Hong Kong

Water Resource Management in a Hard Rock Terrain- A Case Study of Jharkhand State, India

S. P. Singha*, B. Singhb

abCambridge Institute of Technology, Tatisilwai, Ranchi -835103, India

Abstract

Water is a precious natural resource. The major portion of Jharkhand state stands on hard rocks which lack primary porosity. The water bearing capacity of these rocks depends on their ability to develop secondary porosity, Rapid Industrialisation & Urbanisation have increased the demand of water in all spheres. Therefore, the conservation & efficient water resource management is essential. The paper is mainly confined to outline the Geology, geohydrology, aquifer characteristics, quality of water etc and suggests measures for water resource management in Jharkhand.

© 2012 The Authors. Publishedby Elsevier B.V.

Selection and/or peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society Keywords: Secondary porosity, Geohydrology, Aquifer, Water resource Management

1. Introduction

Water is a precious natural resource, a basic human need and prime national asset. The extent to which water is plentiful or scarce, clean or polluted, beneficial or destructive, influence the quality of human life. The total resource available is 24o B.C.M. of surface water along with the ground water recharge every year. It would be 430 B.C.M. of water every year. If we add both the surface & ground water our Resource is excess in demand. Now the question arises where have we gone wrong? The answer depends upon the recent Techniques and Management Strategies applied in water resource management.

* Corresponding author.

E-mail address:sureshprasad_singh@yahoo.co.in

2212-6708 © 2012 © 2012 The Authors. Published by Elsevier B.V.

Selection and/or peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society doi:10.1016/j.apcbee.2012.03.040

2. Ground Water Development in Hard Rocks

From the hydro-geological point of view the hard rock are those lithological units which lack primary porosity. All the igneous and metamorphic rocks namely granite, gneisses, schists, khondalites, dolerites, gabbro, basalt etc. can be grouped in this category. The water bearing capacity of these rocks depend on their ability to develop the secondary porosity which depend on the nature and extent of geological, structural and tectonic processes. Consequently, a high degree of variations are seen even within a given rock type. This is why the hydraulic properties of the hard rocks are very complex. The development of secondary porosity in hard rocks is controlled by lithology, tectonics and climates.

Weathering also enhances the porosity of the rock formation. These processes generally converts the massive rock into a granular rock. In any hard rock terrain generally two types of zones are recognized. The first one is the weathering rock mantle near the ground surface which occur as more or less a granular material. Here, the porosity is inter-granular and this zone behaves like a granular aquifer medium. This zone underlain by the bed rock where the fracture porosity is the controlling factor. This zone is generally unaltered and devoid of water bearing capacity. However, the network of horizontal and vertical joints and fracture make up the aquifer system.

3. A Case Study of Jharkhand

The state of Jharkhand is plateau region with geographical area of 79.714 Sq. Km with 2.60 crore population. The state is endowed with vast natural resources viz. Mineral resources, Water resources, Forest resources, etc. The state lies between latitude 21o 58' to 25o 18' N to longitude 83o22' to 87o 58' East. Its capital Ranchi is located on line of Cancer (lat. 230 30'N). The area and population of state are 2.4% & 2.6% of the country respectively. After creation of the state water scarcity is increasing as additional people are staking their claims to the water resources of the Region. The manifestation of water scarcity is reflected in some of the dry rivers. Over pumping of ground water is common in some parts of Jharkhand, specifically in key food producing regions. The falling water table due to over pumping is an important phenomenon witnessed in some parts of the state. The water table is falling at the rate of 0.4 m/year, forcing people to bore deeper and deeper. The recharge of aquifers is negligible as compared to extraction of water. Due to loss of Topsoil of cropland, the food security is at risk. The cropland is decreasing due to construction of factories, roads in urban areas. Soil erosion is a common phenomenon resulting in decrease in agricultural production. The rapid industrialization and urbanization of the state have increased demand for water resources for industrial, agricultural and municipal uses. It is therefore imperative that the potentiality of water resources is deciphered so that this precious natural resource can be judiciously used for improving socio-economic condition in this state of Jharkhand.

4. Availability of Water Resource & Drainage

The annual rainfall in this region varies between 800 to 1800 mm, the average being 1300mm, but their regional distribution is highly variable on account of the disposition of hill ranges. The Eastern & NW of the state gets lesser rain and as they fall under rain shadow area. Topographically it is collage of sub-plateaus which are characterized by steep slopes to rolling relief. This Geomorphic configuration create more surface rain off in very short duration. The climate is moderate, however, the temperature goes as high as 43 °C at few places during summer. The rainfall, the topography, hill slopes, forest and waste lands cause greater percentage of surface flow. The geology and Geohydrological features do not permit heavy infiltration of rainfall because of hard rock terrain. The natural recharging of ground water is only about 10 - 12% of the surface flow. The state of Jharkhand has 12 major river basins and other

small streams draining outside the state.

The total available surface water in Jharkhand state is 23789 MCM out of which only 4777 MCM of water is being utilized for irrigation, drinking water and industries. The total ground water available in the state is 4992 MCM out of which only 1328 MCM water is being utilized for different purposes. Thus total surface and ground water unutilized is 23677 MCM. Thus we are utilizing only 21.20% of total water resources at present.

It is essential to utilize the 78.8% of unutilized water. The state of Jharkhand is drained by seven major river system viz. Subarnrekha, South Koel, North Koel, Damodar, Sankh, Ajay & Mayurakshi, besides other streams. There are number of drainage axes, sharp and well defined. The major rivers namely Damodar, Subarnrekha, South Koel and Sankh etc. moving roughly in SE direction and discharge their waters in Bay of Bengal. The rivers are mainly rainfed. There is little seepage of ground water in hard rock terrain. However, the high gradient of streams ensure quick discharge of surface flow. The following drainage patterns are present in the region - Dendritic, pinnate, radial, barbed & parallel.

5. Geology of Jharkhand

The 28th State of India constitute a part of Indian peninsular shield - a stable cratonic block of earth crust. The major portion of the state stand on a hard rock of granite gneiss of archaen age is predominant in the area(singh,1981). The more resistant among them are exposed on the surface as hills. The Chotanagpur Plateau represent a vast area from western part of Bihar to the border of West Bengal in the east. Physiographically, the plateau has been divided into following two parts:

a. Ranchi Plateau

b. Hazaribag Plateau

The Ranchi plateau has flat to undulating topography with occasional ridges. This plateau gradually slopes down towards SE in the hilly regions of Singhbhum. The most important lithological unit comprise Archean Metamorphites with associated intrusives and sedimentaries belonging to Gondwana Supergroup and their associated rock. The Vindhyan Limestone and shales are also present in NW part of the state. The Rajmahal hills in NE extremities of Jharkhand are made up of Jurassic Volcanic flows & intertrappians. The tertiary laterites, bauxites and lithomarge present in some parts of the area.

6. Hydrogeological Set-up

Ground water development in hard rock terrain is of special importance. The various geological formation present different ground water conditions in the area. The search for ground water, its development and management is a serious problem to be reckoned with. Hydro-geologically, the entire area of Jharkhand can be divided into following two parts - (a) Hard rock areas & (b) Soft rock areas. For a detailed knowledge of groundwater resource, it is essential to know the following features:

a. Nature and extent of aquifers

b. Depth

c. Form & slope of water table

d. Recharge and discharge of ground water in relation to lithology. The Geomorphic setting and chemical characters of ground water.

Ground water in the area is replenished mainly by the atmospheric precipitation. The ground water is generally not enriched by seepage of river water because rivers are effluent in nature. The depth of water table and the fluctuation depends on:

a. Rainfall

b. Geomorphological features

c. Lithology

During the period of rainfall the fluctuation of water table is observed in some of the area. The ground water occurs in hard and crystalline rock, laterites and riverine sands. About 80% of area of Jharkhand is covered by hard crystalline igneous and metamorphic rocks of Precambrian age. In majority of cases the hard rock form the acquifers. However, in some areas laterites and reverine sands form good aquifers near the river bank. The Archean and Precambrian which almost occupy the entire area are of very low porosity due to compactness and consolidated nature as such permeability is very low.

However, appreciable porosity and permeability are developed through formation of secondary porosity by fracture, fissures, joints and weathering of the rocks.

The fractures and joints form the passage for the movement of ground water and act as reservoir of ground water also. Summarily it can be concluded that the ground water in the area is controlled by the following factors:

a. Topographical setting

b. Thickness of weathered zone

c. Extent, size, openness and interconnections of joints and fractures.

7. Hydro-geological Characteristics of Formations

Based on water yielding and water bearing capacity of different formations, the following hydrogeological units can be deciphered:

a. Consolidated

b. Semi-consolidated

c. Un-consolidated

8. Consolidated formations

Majority of the area of Jharkhand is underlain by consolidated formation comprising pre-cambrian metasediments. These rock are very hard and compact and the ground water occurs mainly in secondary porosity and the fractured zones form the repositories of ground water.

Mantle possesses considerable porosity. The success of well depends on number of openings present in rock. In contrast to schist & phyllite they are better aquifers because of open nature of joints and shallow depth and porous nature of weathered material. On the basis of geologica, structural and topographical control, the aquifers of the area are broadly classified as:

a. Weathered zone forming shallow aquifers

b. Fractured zone forming deep aquifers

9. Shallow aquifers (Weathered Zone)

The weathered residue, the fractured rock, laterites as well as saturated alluvial material among the river courses are considered as shallow aquifers. The following are the factors affecting shallow aquifers:

a. Geological control

b. Topographic control

c. Structural control

10. Deep aquifers

Occurrence of highly permeable intensively fractured deep seated aquifers have been established after detail hydrogeological, geophysical and morphotectonic studies followed by exploratory drilling, they may be broadly divided into two types, namely:

a. Vertical fracture &

b. Horizontal fracture and form semi confined and confined aquifers. The following factors affect the deep aquifers:

a. Tectonic and structure

b. Geology

c. Topography

11. Quality of Ground Water

Industrial effluents, increasing population and rapid urbanization have caused deterioration of ground water quality. Further indiscriminate use of agro chemicals & fertilizers have also affected the quality of ground water. However, the overall quality of ground water in Jharkhand is not alarming and still suitable for drinking and irrigation purposes.

In Damodar basin area the Biocarbonate & electrical conductivity are less than 200 mg/litre and 500 Micro mhos//cum. In Subernrekha, the S.P. Conductance is between 530 to 1073 Micro mohs/cum. In Brahni Basin, contains low bicarbonate and chloride.

12. Chemical Analysis Data

The Chotanagpur granite gneiss terrain, maximum concentration of Na+ K+ , Fe & Mn is observed. The schistose rock contains maximum concentration of chloride, fluoride , sulphate and bicarbonate.

The PH value is within desirable limit(Kumar,2002). The ground water of some of the area is hard and therefore is not useful. However, the quality of water is not alarming except of few areas.

13. Water Resource & Management

Fig. 1. Observed and projected decline in per capita average annual fresh water availabiligy and growth of population from 1951 to

2050 Mall R.K 2006

Rapid industrialization and urbanization in Jharkhand have increased the demand of water in all spheres. We are utilizing only 21.20% of total water resources at present and rest 78.8% remains unutilized. Therefore, the conservation and efficient water resource management is essential. The management and reuse of irrigational water will adequately help water resource management in Jharkhand. In the hilly area, where the slope is high the plantation of green vegetation is required. The conservation of water by optimum surface and ground water development without wastage is required. To enhance the natural supply the recharge is also required in the following manner:

a. Artificial recharge by Basin Stream Channel, ditch & furrow, pit method

b. Construction of check dams, Recharge well in suitable areas

c. Rain harvesting techniques should be applied in townships and rain shadow zone.

14. Recommendations for water resource management in Jharkhand

• Identification of water scarce area

• Development of water shed area

• Study of soil type

• Recycling of used water

• Assessment of water requirement in industries and Agriculture

• Identification of Recharge discharge area

• Identification of potential aquifer zone

• Study of secondary porosity in hard rock

• The sedimentation of major river basis and possibility of disilting should be explored

15. Geological intervention

• An integrated geological investigation programme taking into account, the lithology and structure as the first leveled base data.

• Disposition of hill ranges and slope studies should be given due consideration.

• The weathered mantle specialty the lateritic zone should not be excavated for road materials as these are the most important litho unit for conservation of rain water.

• The Remote Sensing Data should be utilized in land zonation planning and GPS & GIS be employed to form an integrated mode of management of water resources.

16. Conclusion

There are alternative and substitutes to other natural resources, but not to the life's elixir which has sustained us on earth for millions of years now. Technology cannot create water, but can only prolong its life through developing conservative tools and equipments for water use in homes and industries, recycling (by purifying) wastewater for reuse, and desalinizing the seawater for portable use .The water auditing *systematic exploration &exploitation & proper management of this heavenly asset is need of the hour.

References

[1]. Singh S.P.- Petrochemistry of Archaean and associated rocks of the region, north of Latehar, Dist. Palamau, Bihar, Ph.D. thesis, Ranchi University, Ranchi 1981.

[2]. Kumar, R - Hyodrogeological investigation in and around Industrial area of Ranchi, Jharkhand with special reference to ground water pollution , Ph.D thesis, Patna University, Patna,2002.

[3]. Mall R.K: Water resources and climate change, current science, vol. 90.No.12, 2006.