CHAPTER I I Chapter I

CHAPTER I i Chapter I INTRODUCTION Prologue : Coates (1981) while discussing the subject matter of environmental geology and providing guidelines to serve as focal themeg! for various topics, putforth ten concepts dealing with physical systems and geological fundamentals, causes and status of problems, and resolution of problems and environmental ethics. One of these concepts says that the human-induced changes of the land and water invariably produce environmental feedback system. Feedback is the environmental manifestation of Newton's second law of motion, that is, for every action there is an equal and opposite reaction. Man when enters the physical system and tries to modify one or more of its components breaks the boundary and creates noise rather than music. The ways, scales and time-frumes of feedback differ and depend upon the manner, degree and intensity of the man-induced changes. When man constructs the dam to get water tjor drinking, agricultural or industrial purposes prevents the floods that can fertile the land downstreams, when he circulates the stored water through network of channels that create the problem of water logging and in the process he adversely changes the - 2 - hydrogeological regime. In order to compensate unfavourable changes he then starts constructing other types of minor structures which can maintain the hydrogeological regime of the downstream areas. In both cases, tfe-e major and minor structures, he selects the river or stream basins as logical areal units within the framework of which he conveniently collects, analyses and interprets the desired data and decides the points where hydrological cycle can be Intervened. The need to interven the hydrological cycle becomes more evident in the drought prone areas : for bringing more land under cultivation5 meeting drinking water supply and feeding the requirement of industries. The need is further realised in the terrains comprising of rocks of low permeability and marked by geological features which adversely impart heterogenity over the occurrence of groundwater. The upper Mula river basin situated close to Pune City is undergoing rapid changes in the hydrogeological rfagime subsequent to the agricultural and industrial growth during last decade. The ba3in is developed along the eastern flank of the western ghats constituted of horizontally disposed basaltic flows which are known for their low permeability and association of geological features liko dykes and red beds. The western part of the basin receives heavy rainfall of the - 3 - order of over 4000 nun} "but much of the water is carried away as surface runoff as a result of which inhabitants residing in such areas face accute scarcity of water immediately after winter months. As a remedial measure the government of Maharashtra has undertaken a number of projects either for storing surface water or fox enhancing recharge in the aquifers. The author, therefore, selected the upper Mula river basin to study its physical parameters and their impact on surface and groundwater occurrences. Objectives : The present investigations were initiated with \ following aims and objects (Fig. 1.3) : (1) To study the distribution of rock types and to evaluate the soil characteristics (2) To collect and analyse the available meteorological data. (3) To find out drainage parameters by conducting norphometric slope- and hypsometric analyses. (4) To conduct hydrogeological surveys including well inventory and pumping tests in representative areas. (5) To employ electrical resistivity method and bore hole logging techniques. •J 3 U) QJ !_n a> C l ■X) "O OJ C l O "O ro c ro CL O cn L l - 4 - (6) To assess the chemical quality of surface- and ground waters. (7) To conduct the inventory of engineering structures like Kolhapur-type weirs and minor irrigation tanks. (8) To integrate the above information for knowing its impact on agricultural landuse. The area : The upper Hula river basin lies between 18°25' N to 18°4o’ N latitudes and 73°20l E to 73°50* E longitudes and occupies an area of about 735 sq. kj^s. The basin is included in the Survey of India’s toposheet Nos. 47 F/6, 47 F/7, 47 F/lO s 47 F/ll, 47 F A 4 and 47 F A 5 in the scale of 1" = 1 mile. The basin covers the major portion of Mu]shi taluka of Pune district with its headquarter at Paud. A small portion in .north-eastern and eastern part of the basin falls in Haveli taluka of Pune district. There are 95 villages present in the basin important amongst them being Aundh, Pashan, Mahalunge, Sus. Ehugaon, Pirangut, Ghotaude, Darvali, Paud, Wakad, Kolvan, Mulshi etc. (Fig. l.J). The western part of the basin, covering catchment area of Mulshi dam, exhibits dissected topography and is deeply - 5 - forested. The area is not easily accessible. However, steamer service is available from Mulshi dam for approaching settlements in this part. The villages Pashan, Bhugaon, Pirangut, Darvali, Paud, Mulshi etc. are approachable by State Highway No. 38 and remaining villages are interconnected by a network of unmetalled roads, cart-tracks and foot-paths. Review of litersture ? A review of literature suggests that only preliminary work on geomorphological and hydrogeological aspects of the basin has been conducted. Jog (1970) studied, in brief, the geomorphology of the basin. Phadke and Sukhtankar (1971) carried out slope analysis of the Chatushringi hill. Kanegaonkar (1977) recorded the presence of faa' and 'pahoehoe' flows in the Pashan area. Pawar et al (1982) studied the chemistry of groundwaters in the eastern most part of the basin. Hydrogeological aspects of the basin have been briefly studied by Saxena (1983), Thigale (1983, 1984) and Kelkar (1984). Methodology : The geological mapping was carried out by taking traverses in the north-south direction. The morphometric analysis was carried out using Survey of India’s tcposheets with 1 ” = 1 mile scale'following Hortonian concept (1945). Stream lengths were measured with the help of rotameter and - 6 - basin areas were computed with the help of 1" scale graph paper. Meteorological data was collected from Indian Meteorological Department of Government of India, Environmental Engineering Works Division and Tahsildar's office of Government of Maharashtra. Water samples were analysed as per the standard methods suggested by APHA, AWWA, WPCF (1975). Well Inventory data collected on village revenue maps, was utilised to prepare the water table contour map3. Pumping tests were conducted using automatic water level recorder manufactured by M/s Hindustan Watch Co., Pune. Resistivity surveys were conducted using A.C. type aquameter and bore hole logging was carried out by employing aqua-logger manufactured by Sparkonix (India), Pune. Data pertaining to Kolhapur type weirs and minor irrigation tanks was collected from Irrigation Department, Government, of Maharashtra, Pune. The agricultural landuse data \/as collected from the Tahsildar's office of Paud..

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