018147   Ahmad S M;Dayal A M;Padmakumari V M;Gopalan K (NO, National Geophysical Research Institute, Uppal Raod, Hyderabad-500 007) : Evolution of strontium isotopes in seawater during the middle miocene: new results from ODP site 758A. J Geol Soc India 2000, 55(3), 307-16.

⁸⁷Sr/⁸⁶Sr ratio of seawater has increased significantly over the last 40 Ma. This increase was marked by very high rate of increase in ⁸⁷Sr/⁸⁶Sr and almost zero growth rate. The middle Miocene is one such period when considerale changes in the slope of ⁸⁷Sr/⁸⁶Sr curve have been reported. This study tests and improves on previously published strontium isotopic records for this period. Report, 34 high precision strontium isotopic analyses of well preserved planktonic foraminifera from Ocean Drilling Program (ODP) site 758A in the eastern Indian Ocean. This site was selected because of the high quality magnetostratigraphy, suitable sedimentation rate (0.3 to 1.5 cm/ka) and excellent preservation of calcareous microfossils in sediments. Samples studied represent the period from 15.2 Ma to 10.3 Ma with approximately one sample per 100-200 ka. The results show that the seawater ⁸⁷Sr/⁸⁶Sr ratio during this period increased from 0.70881 to 0.70892. The rate of increase in ⁸⁷Sr/⁸⁶Sr during 15.2 Ma to 14.3 was -31x10⁶ / m.y., whereas significantly from 14.3 to 12.8 Ma it was about a factor of two higher (-59x10⁶/m.y.). High rate of growth in seawater ⁸⁷Sr/⁸⁶Sr during this interval indicates exceptionally high rate of continental weathering. However, during 12.8 to 10.3 Ma the growth in ⁸⁷Sr/⁸⁶Sr of seawater remained almost constant with an average value of 0.708914. This constant value may be due to decrease in weathering rate of continents as a result of extensive glaciation. It is suggested that the tectonic uplift and denudation of Himalayas coupled with climatic changes have resulted in the variations of seawater strontium isotopes during this period. The inflection points in the curve may be used as event marker for stratigraphic correlation of marine sediments.

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018146   admanabhamurty P;Jain I (School of Environmental Sciences, Jawaharlal Nehru University, New Delhi-110 067) : Turbulence studies at dry and moist convective regions of monsoon through during different phases of monsoon. Mausam 1999, 50(1), 9-18.

Utilising the slow and fast data the towers, a comparative study of turbulence parameters i.e. frictional velocity (u_*), temperature scale (θ_*), turbulence intensities, sensible heat flux (H), surface momentum flux (τ) and eddy diffusivity (K_m) during the three phases of monsoons i.e. onset, mid-monsoon and end-monsoon between the moist convective station Kharagpur (23.3°N, 87.2°E) and dry convective station Jodhpur (26.3°N, 73°E) was made. Trends were similar in the diurnal variation of sensible heat flux computed by eddy correlation (direct method) with profile method (indirect method), however, indirect method overestimated the flux.

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018145   Acharyya S K;Roy A (NO, Geological Survey of India, 27, Jawaharlal Nehru Road, Calcutta-700 016) : Tectonothermal history of the central Indian tectonic zone and reactivation of major faults/shear zones. J Geol Soc India 2000, 55(3), 239-56.

Central Indian Tectonic Zone (CITZ), which divides the Indian subcontinent into Bundelkhand Block in the north and the Deccan Block in the south, is represented by a collage of different lithotectonic terranes ranging in age from Archaean to Recent. It comprises two parallel structural domains, namely the Son-Narmada (SONA) subzone in the north and the sausar mobile belt (SMB) in the south. The ancestry of the SONA subzone is indicated by the Neoarchaean - Palaeoproterozoic ages yielded bythe rocks of Mahakoshal fold belt; the Sausar belt, on the other hand, has yielded Meso- to Neoproterozoic ages. The present response of CITZ to accumulation of stress and attendent seismicity is governed by the structures generated due to early tectonic history of rocks within it, particularly the development of number of E-W to ENE-WSW striking, brittle and ductile shear zones. While the Sausar belt has remained more or less stable since the late Precambrian, the SONA and Tapti lineament zones have been reactivated several times. Two prominent ENE-WSW trending deep faults, termed the Son-Narmada North fault (SNNF) and Son-Narmada South Fault (SNS) have been episodically active from Neoarchaean onwards. The SNSF in particular has witnessed protracted reactivation well into the Phanerozoic. Intraplate seismicity in continents is commonly concentrated along ancient fault zones. Reactivation of faults of shear zones is favoured over new fault generation, since the SNSF is in a high shear stress orientation. Although the Sausar mobile belt is marked by a number of E-W trending parallel ductile shears, mass transfer processes such as silicification, recrystallization and grain growth during Precambrian appear to have healed them.

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016996   Verma B C;Vashisht G D (Senior Geologist (Retd.) GSL., , Vill. and P.O. Chetru, Kangra-176 209) : Record of a molar tooth of elephas (hypselephas) hysudricus from upper Siwalik, Una district, Himachal Pradesh : phyletic relationships of the species and its bearing on age of the beds. Geosci J 1998, 19(2), 79-85.

Records occurrence of a molar tooth, ascribed to Elephas (Hypselephas) hysudricus Falconer and Cautley collected from the folded strate exposed south of Ispur, Una district, Himachal Pradesh. The rocks in this area so far had been tentatively reffered as Upper Siwaliks without any comment on the age of the constituent units. The presence of this form helps in assigning Pinjorian (Lower Pleistocene) age to the source beds. Elasmodont elephants particularly Elephas (Hypselephas) hysudricus appeared in the Indian subcontinent in Late Pliocene and attained prolific distribution in the Siwalik region dui ing the lower Pleistocene. The species, believed to be the immediate ancestor of extant Asiatic elephant Elephas indicus, however, became extinct before the beginning of Middle Pleistocene. Fossilised cranial parts of this form serve as excellent age indicators because of its limited temporal range.

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016995   Thangarajan M (NO, National Geographical Research Institute, Hyderabad-500 007) : Evaluation of site suitability for disposing of solidwaste using waste aquifer isolation principle. J Geol Soc India 1999, 54(5), 529-43.

Primary concern in selecting waste site is the need for isolating the waste site from the fresh water zones, e.g., water table. It implies that there should be an impermeable zone for pollutant migration between any waste site and groundwater regime. The unsaturated zone, otherwise called the vadose zone, that lies between the topsoil and water table forms the most important natural attenuating zone for the migration of leachate. Thus, there is a need to select a site, which has very low permeable and absorbing vadose zone. Selection of an ideal site needs rigorous field investigations, followed by mass transport modelling. In case scarce resources of money and time, one needs a few faster methods based on empirical approach to identify the disposal site. One such empirical method is to identify a site, which has good attenuation potential for the leachate produced by the waste pile. This is termed as waste aquifer isolation principle (WAIP). This will restrict the contaminant migration to reach the water table within short span of time. This principle makes use of the hydrogeologic criteria using the data related to type of waste and area to be disposed, quantum of pollutant, effective porosity, thickness of unsaturated zone, and vertical permeability of the medium. A computer code WASP, based on the above principle, was used to compute an index to decide upon the suitability of the site.

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016994   Tewari V C (NO, Wadia Institute of Himalayan Geology, Dehra Dun-248 001) : Prospects of delineating terminal proterozoic and precambrian-cambrian boundary in the north-eastern Himalaya. Geosci J 1998, 19(2), 109-114.

Prospects of delineating a tentative Precambrian-Cambrian boundary in the Buxa-Miri Group of the eastern Lesser Himalaya was documented by Tewari (1984b). Since then, no attempt is made in this direction. The Terminal Proterozoic and Precambrian-Cambrian boundary is now well established in the Blaini-Krol-Tal sediments of the Central sector of Lesser Himalaya. A similar detailed and multidisciplinary integrated study of stromatolites, trace fossils, acritarchs, Ediacaran biota and stable isotope geochemistry and chemostratigraphy is required in the Ranjit window (Sikkim-Darjeeling) and, Siang district of the E and NE Himalayas for demarcating Terminal Proterozoic and PC/C Boundary.

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016993   Singh P;Porwal D K;Uddin I (Dr. B.R. Ambedkar Regional Geoscience Laboratories, Oil Natural Gas Co, , Makarpura Pura Road, Vadodara-390 009) : Microfauna and calcareous nannoplankton from the subsurface tertiary sequence of Chanasma wells B and C, Mehsana block, Cambay Basin, Gujarat. Geosci J 1998, 19(2), 87-99.

Microfauna and calcareous nannoplankton of the Olpad Formation (Paleocene), the Kalol Formation (Middle Eocene), the Tarapur Formation (Middle-Upper Eocene), the Babaguru Formation (Lower Miocene) and the Kand Formation (Lower Miocene-Middle Miocene) of the Chanasama wells-B and C have been studied. The Olpad Formation of both the wells has not yielded foraminiferids and calcareous nannoplankton, whereas the overlying Kalol Formation and Tarapur Shale of both the wells have yileded foraminiferids and calcareous nannoplankton. The unconformably overlying Babaguru and Kand formation of both the wells have yielded broken shells of lamellibranchs. On the basis of foraminiferal assemblage, the top and botton of the Middle Eocene have been marked at 1100 m and 1140 m respectively in the Chanasama well B, which contains Upper Eocene foraminiferids between 1080 m and 1100 m interval within the Tarapur Shale. In Chanasama well-C, the top and botton of the Middle Eocene have been marked at 1095 m and 1120 m respectively and the top Upper Eocene has been marked at 1080 m on the basis of the foraminiferal assemblage.

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016992   Sengupta S;Chakraborty A;Bhattacharya H N (Department of Geology, Presidency College, 86/1 College Street, Calcutta-700 073) : Fossil polyplacophora (mollusca) from upper Talchir sediments of Dudhi Nala, Hazaribagh, Bihar. J Geol Soc India 1999, 54(5), 523-7.

External casts comparable with Polyplacophora (Mollusca), collected from the sand/siltmud alternation facies (Turbidite) of upper Talchir sediments of Dudhi Nala, West Bokaro basin, Hazaribagh district, Bihar are described and illustrated here for the first time. The sediments were reported to be unfossiliferous. Polyplacophoran morphology of the fossils indicate a marine link of the West Bokaro basin during the upper Talchir times. Dudhi Nala area is presently considered to he yet another locality proximal to the eastern limit of the Lower Permian marine incursion in the Indian peninsula along the Raniganj-Daltonanj-Manendgragarh-Umaria belt.

016991   Reddy I V (Geological Survey of India, Southern Region, , Hyderabad-500 068) : Occurrence of ultra-potassic volcanic rocks in the proterozoic Cuddapah basin. J Geol Soc India 1999, 54(5), 467-71.

This note records for the first time the occurrence of ultra-potassic volcanic rocks in the Proterozoic Cuddapah basin. The ultra-potassic rocks occur within the tuffaceous sequence of the Pullampet Formation of Nallamalai Group of Cuddapah Supergroup in the area around Naiduvaripalle in Cheyyeru valley in the Cuddapah District of Andhra Pradesh. Petrographic Studies reveal that the rock is aphanitic with phenocrysts of alkali feldspar set in a finely crystalline groundmass of slender feldspar microlites and chlorite. The rock displays typical ultra-potassic chemical characters in having high K2O>8%, K2O:Na2O>25% and MgO>3%.

016990   Radha Krishna Murthy B;Venkatraman P (Deptt. of Civil Engg., K.S.R.M. College of Engg., Cuddaph) : Stochastic analysis of hydrologic drought in Pennar basin. J Indian Wat Resour Soc 1999, 19(1), 19-22.

Stochastic analysis for prediction of hydrologic drought in Pennar basin of Andhra Pradesh is presented. By fitting the standard type-1 extreme value distribution (GUMBEL'S), the drought parameters viz., severity and duration are estimated. The distribution was fitted to stream flow data at Sangam anicut and at Upper Pennar Proiject (U.P.P) and rainfall data at Cuddapah raingauge station. From the analysis, it is observed that the Gumbel's distribution fits well for all cases except for mild drought case of Upper Pennar Project. The results of the drought severities and drought durations for various return periods using the fitted distribution are presented.

016989   Pawar N J;Nikumbh J D (Department of Geology, University of Pune, Pune-411 007) : Trace element geochemistry of groundwater from Behedi basin, Nasik district, Maharashtra. J Geol Soc India 1999, 54(5), 501-14.

Trace element geochemistry of groundwater from Behedi basin have shown spatial as well as temporal variations. While the spatial variations have been attributed to land use practices in the basin, the temporal changes indicated input of trace elements from soil zone due to rain-fed recharge. On the basis of spatio-temporal variations, weathering of rocks and human activity have been identified as the potential sources of trace elements in the groundwater. The budgeting of trace elements in the groundwater suggests that the rate of flushing of Cu is highest from the vadose zone to phreatic zone followed by Fe, Zn, Mn, Pb and toxic trace elements like Hg and As.

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016988   pandarinath K;prasad S;Gupta S K (Physical Research Laboratory, , P.O.Box. No. 4218, Navrangpura, Ahmedabad-380 009) : A 75 ka record of palaeoclimatic changes inferred from crystallinity of illite from Nal Saroval, western India. J Geol Soc India 1999, 54(5), 515-22.

Crystallinity of the clay mineral illite, which is a climatically sensitive parameter, was studied for palaeoclimatic inferences from a core raised from Nal Sarovar in western India. The changes in crystallinity of illite in the top 3m of the core showed that the climate was wetter than present from -6.3-4.6 ka BP and was followed by a relatively dry phase which has continued up to the present. These palaeoclimatic observations are largely similar to those obtained from δ¹³C and C/N ratio variations in the top 3m of the core. From the deeper (>3m) section, a wet spell around 50 ka BP was identified in an otherwise continuous spell of aridity between 7 and 73 ka BP. The presence of a red bed dated to <126>50 ka BP (depth 1285-1324 cm) also suggested that the climate was wet followed by dry conditions during this period. This interpretation of palaeoclimatic changes deciphered from the Nal Sarovar core differs in some detail from the Rajasthan palaeoclimatic record and that available from south India.

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016987   Misra D K (NO, Wadia Institute of Himalayan Geology, Dehra Dun-248 001) : Digital computer processing of lineament net with special reference to seismogenic zones in the western Himalaya, India. Geosci J 1998, 19(2), 115-28.

Digital computer processed data of visually identified lineament net recoginzed on low resolution Meteor space imagery in the form of correlation co-efficient values, have been used for delineation of large-scale technically active Seismogenic Zones in the Western Himalaya. Three main recently originated seismically active tectonic zones have been recognized within the Western Himalayan segment. One of the three recognized zones runs parallel to the general Himalayan tectonic trend which represent the imbricate zone of intense thrust faulting. It is proposed to call this as Kangra-Uttarkashi zone in the southwest. The other two zones run perpendicular to the general Himalayan trend as well as to the orographic strike throughout the expance of the Himalaya. These cross-zones represent the zones of extension or more precisely the area of possible tear faulting. It is proposed to call these cross-zones as Satluj Valley cross-zone in the southeast and Nubra Valley cross-zone in the northwest. One large ring structure interpreted from space images appears to be located between the two cross-zones. This ring feature may be considered as an uplifted dome structure originated by younger crustal thickening, metamorphism and granitic magma generation. The epicenter of Kinnaur earthquake (M 6.8) that occured on 19th January, 1975 lies in the vicinity of Satluj Valley cross-zones.

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016986   Mishra K S;Gupta K R;Bagchi A K;Jagmer Singh (Atomic Minerals Division, , Jamshedpur-831 002) : Proterozoic iron oxide type mineralisation in the environs of Dalma volcanics, west Singhbhum district, Bihar. A new horizon for exploration of polymetallic ores. J Geol Soc India 1999, 54(5), 491-4.

Significant uranium geochemical anomalies associated with Cu, Ni, REE, Au indicative of favourable Iron oxide breccia type of mineralization has been located along a sympathetic faulted zone close to the main fault along the northern contact of Dalma volcanic range. The assemblages of the rocks found north of Dalma volcanics viz., carbon phyllite, carbonaceous quartzite, calc-arenite and cherty quartzite are indicative of typical marine environment of lower to middle Proterozoic age traceable for about 10 km over a 3-7 km wide zone. The mineralization represented by iron oxide breccia is confined to a major structural zone parallel to a regional strike fault and is cut across by transverse faults. Significant anomalous concentration of U3O8 (140-770 ppm), Cu (173-498 ppm), Ni (148-1566 ppm), Au (<0.25 to 1.6 ppm), Ag (1.2 to 4.29 ppm) and REE (Y 131 to 607 ppm, LA<50 to 993 ppm Ce 41 to 91 ppm) points to its economic potentiality. The geological characteristics and tectonic set-up are akin to the major iron oxide (Fe-Cu-Ni/U-REE-Au) type of deposits reported elsewhere in the world. Investigation on the economic potentiality of the mineralisation is under progress.

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016985   Mazumdar A (Department of Geology, University of Delhi, Delhi-110 007) : Effect of variations of specimen thickness on illite "crystallinity" measurements. J Geol Soc India 1999, 54(5), 495-9.

`Kubler-index' (Δ2θ) has been extensively used to document degree of metamorphism in very low grade pelitic rocks and to mark the diagenetic-anchizonal and anchizonal-epizonal boundaries. However, variations in sample preparation procedures significantly affect the Δ2θ measurements. The effect of variation in thickness (mg/cm²) of the clay layer on Δ2∞ measurements have been studied. The Δ2θ values drops rapidly for slides with clay loading less than -2-3 mg/cm² and achieve more or less a plateau beyond this thickness. Owing to the rapid change in slope, even minor variation in thickness (which is difficult to constrain) can significantly affect the Δ2θ measurements. Low X-ray intensities recorded for thin slides also add uncertainty to the Δ2θ measurements.

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016984   Mathur U B;Mathur A K (Geological Survey of India, Western Region, , Jaipur-302 004) : Neogene flora from Bikaner, Rajasthan. Geosci J 1998, 19(2), 129-44.

Fossil leaves described in the present work were collected from the clays interbedded with white sandstones of Mar Formation exposed in the china clay qarry 1 Km NE of India (4 Km NNE of Kolayat), district Bikaner, Rajasthan. In all, 11 taxa belonging to the general kayea (Clusiaceae), Sterculia and Pterygota (Sterculiacea), Murraya (Rutaceae), Berchemia (Rhamnaceae), Grewia (Tiliaceae), Millettia (Leguminosae), Diospyros (Ebenaceae), Litsea (Lauraceae) and Ficus (Moraceae) have been discribed. The megaplant assemblage points to a moist to dry tropical semi-evergreen deciduous forest conditions. The stratigraphic position of the Mar Formation above the Jogira Formation (Middle Eocene), general large size of the leaves and affinity of some of these taxa with the Neogene elements suggests the flora to be Neogene in all probability.

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016983   Krishna Rao B;Sethumadhav M S;Prasad M H; Mahabaleshwar T D;Rao A V;Gilg H A (Geology Survey of India, , Sanjivani Nagar,Garha Road,Jabalpur-482 003) : Features and genesis of vein-type magnesite deposit in the Doddakanya area of Karnataka, India. J Geol Soc India 1999, 54(5), 449-65.

Vein-type magnesite deposit of Doddakanya area is situated in the southern part of the Archaean Dharwar craton. Magnesite is confined to a c. 3.3 Ga old ultramafic body which constitutes a tectonically dismembered part of a layered ultramafic-mafic complex emplaced into supracrustal rocks of the Sargur Group. The magnesite-bearing ultramafic body is composed of dunite with minor harzburgite and exhibits varying degrees of serpentinization and weathering. About 50 vol.% of the ultramafic body is serpentinized decreases with depth. The serpentine minerals are represented essentially by lizardite/chrysotile exhibiting pseudomorphic mesh-texture. Serpentinization and the intensity of serpentinization of the ultramafic body took place within 6 km of the Earth's surface at low temperatures (<200°C) and essentially involved volume expansion (isochemical) process. During weathering, the relict olivine of the serpentinized ultramafic body was pseudomorphously replaced by a mixture of amorphous material (with variable amounts of Fe, Mg, Si and volatiles) and minor ferric oxyhydroxides and secondary silica. The Mg mobilized during weathering participated in the formation of magnesite in tensional fractures developed during the late - to post - serpentinization event. Oxygen isotope data (δ¹⁸ = av. 30.6%0SMOW) indicate the precipitation of magnesite at ambient temperature and carbon isotope values

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016982   Kale H S;Krishnamurthi R (NO, School of Studies in Geology, Vikram University, Ujjain) : Ore mineralogical studies of banded iron formation of Mahamaya iron ore deposit, Durg district, M.P. (India). Ultra Scient phys Sci 1999, 11(2), 196-9.

Mahamaya is one of the important iron ore deposit and forms a part of the Dalli-Rajhara iron ore Supergroup. The area lies in Durg district of Madhya Pradesh. Detailed field work, petrographic and ore mineralogical studies have been carried out to unravel the genetic aspects of this important area. Petrographic studies of the sample indicate the mineralogical details and textural aspects of Banded Hematite Quarzite and associated litho-units. Ore mineralogical studies of different ore types exhibit different mode of ocurrence of hematite and goethite. Varieties of textures and the relation with silicate minerals throw light on initial deposition, dissolution and recrystallization of iron ore minerals. Based on the above aspects a detailed textural and mineralogical information with reference to the genesis and leaching process of iron ores have been proposed.

016981   John Kurian P;Krishna M R;Nambiar C G;Murthy B V S (Department of Marine Geology and Geophysics, Cochin University of Science and Technology, Cochin-682 016) : Interpretation of gravity field over the Perinthatta anorthosite, northern Kerala. J Geol Soc India 1999, 54(5), 483-90.

Gravity surveys have been carried out over the Perinthatta anorthosite and the adjoining areas and the results are discussed. The Bouguer anomaly map reveals the absence of any conspicuous gravity anomaly corresponding to the pluton and thus precludes the existence of larger mafic portions of the pluton in the immediate subsurface region. The residual gravity map obtained by regional residual separation method shows a minor positive gravity field of irregular shape with localised highs of 6 - 12 mgal within and around the anorthosite body. Two-dimensional gravity interpretation of profiles across the pluton suggests subjacent nature and lensoid shape for the anorthosite which is underlain by small isolated cylindrical bodies (≈ 2.5 km diameter) of higher density (2.9 gm/cc) extending 3-7 km downwards. These cylindrical bodies are inferred as either the mafic/oxide rich portions of the pluton sagged down during crystallization or the individual feeders of the plagioclaserich mushes, which coalesced in the upper crust to give rise to the massif.

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016980   Das P K;Borthakur J (Department of Geological Sciences, Gauhati University, Guwahati-781 014) : Geochemical studies of modern sediments of the Brahmaputra river around Nimatighat (Jorhat), Assam. Res J Chem Envir 1999, 3(1), 17-22.

Geochemical studies of modern sediments of the Brahmaputra river were carried out to determine the source, nature of sediments, depositional environment and pollution limits of the sediments. For this purpose, both major and trace elements were studied. The relationship between the oxides of major elements were also studied. The sediments contain low SiO₂/Al₂O₃ and high Fe₂O₃/K₂O ratio which indicates mineralogical immaturity. The chemical study reveals that the sediments were derived from both igneous and metamorphic source rocks and contain environment sensitive trace-elements. Moreover, the elements like Cr, Ni, Co, Zn, and Pb are concentrated in the sediments below toxic limit and hence the sediments can be called unpolluted. Moreover, from the study, it is confirmed that these elements indicate the fresh-water depositional environment. The organic matter content is not much high due to influence of oxygenated water.

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016979   Chaube U C (NO, W.R.D.T.C., University of Roorkee, Roorkee-2447 667) : Model study of conjunctive use for irrigation in major tributary sub - basin of ganga basin. J Indian Wat Resour Soc 1999, 19(1), 1-7.

Three season deterministic linear programming models were used to evaluate impact of conjunctive use of surface and ground water on irrigation policy and available balance runoffs in the Ganga basin. The study relates to a future stage when the projects under construction and some prospective projects (in Nepal) are likely to be implemented. The models were used to analyse irrigation development in the eight major tributary subsystems under three conditions namely (a) when only surface water is used for irrigation, (b) when surface and ground water is conjuctively used, but ground water used is limited to natural recharge and (c) when kharif channels are used to artificially recharge the aquifers and ground water use is confined to irrigation during rabi and summer seasons only under the conjuctive use plan for surface water and groundwater. The study indicates that ground water development and its conjuctive use is an important technological option and it may become an important policy issue in view of its regional implications such as providing irrigation to larger areas, control of floods and augmentation of lean season flows.

016978   Camerlengo A L;Demmler M I;Mohd. Atan K A; Awang M;Said M Z M;Saadon M N (Faculty of Applied Sciences and Technology, Universiti Putra Malaysia, Terengganu Mengabang Telipot 21030 Kuala Terengganu Malaysia) : Climatological variability due to the 1982-83 ENSO event in East Malaysia. Ultra Scient phys Sci 1999, 11(2), 134-9.

Departure from historical values of selected meteorological parameters during the 1982-83 ENSO event in East Malaysia is addressed. It is shown that during this particular ENSO event there was a deficit of precipitation in both Sabah and Sarawak. Concomitantly, a positive anomaly of both surface monthly pressure and monthly air temperature during this same period were detected.

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016977   Camerlengo A L;Awang M;Atan K A;Saadon M N; Ambak M A;Demmler M I (Faculty of Applied Sciences and Technology, Universiti Putra Malaysia, Mengabang Telipot 21030 Kuala Terengganu Malaysia) : 1988 El Viejo event in Malaysia. Ultra Scient phys Sci 1999, 11(2), 155-61.

Disruption of the climatic pattern of Malaysia due to the 1988 El Viejo event is addressed. Investigation indicate a strong response to the 1988 El Viejo event in East Malaysia; while a moderate to weak response in Peninsular Malaysia. Similar responses had been obtained for El Nino events. Negative temprerature anomalies should occur during El Viejo events. Positive temperature anomalies recorded all throughout 1988, suggests that an increase of temperature, of aproximately 0.3<144C to 0.5°C, has taken place in Malaysia during the last thirty years. Strongly feel that this is due to global warming.

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016976   Camerlengo A L;Awang M;Atan K A M;Husain M L; Said M Z M;Saadon M N (Faculty of Applied Sciences and Technology, Universiti Putra Malaysia, Terengganu Mengabang Telipot 21030 Kuala Terengganu, Malaysia) : Comparative study of the precipitation pattern of both peninsular Malaysia's east coast and east Malaysia. Ultra Scient phys Sci 1999, 11(2), 176-80.

Interannual sea surface temperature variations between late November and February cause fluctuations in the monsoon rainfall over East Malaysia. Study may be viewed as a continuation of that manuscript. The results shows that the Intertropical convergence Zone is displaced further southwards in Peninsular Malaysia's east coast as compared to East Malaysia during the northern hemispheric winter season.

016975   Camerlengo A L (Faculty of Applied Sciences and Technology, Universiti Putra Malaysia, Terengganu Mengabang Telipot 21030 Telipot 21030 Kuala Terengganu, Malaysia) : Initialization of a Baroclinic ocean model. Ultra Scient phys Sci 1999, 11(2), 219-21.

Implementation of accurate initial conditions is being recognized as a crucial problem in oceanic modeling. A set of initial conditions for the vertical internal structure of the ocean are derived.

^ssc

016974   Baidya T K;Mondal S K;Balaram V;parthasarathy R;Verma R;Mathur P K (Department of Geological Sciences, Jadavpur University, Calcutta-700 032) : PGE-Ag-Au mineralization in a Cu-Fe-Ni sulphide-rich Breccia zone of the precambrian Nuasahi Ultramafic-mafic complex, Orissa, India. J Geol Soc India 1999, 54(5), 473-82.

Precambrian ultramafic-mafic plutonic complex of Nuasahi, Orissa in the Eastern Indian Shield represents at least three suites of magmatic intrusion; (i) an interlayered sequence of enstatitite, websterite (± olivine), dunite, chromitite, harzburgite and orthopyroxenite; (ii) massive gabbroic suite with minor bodies of norite, anorthosite and bands of titaniferous magnetite and (iii) dykes and sills of dolerite and clinopyroxenite. A prominent breccia zone is developed near the interface of the first and second magmatic suites in the eastern part of the complex including the Shankar chromite lode and the ultramafic host of the first suite, and the gabbro-noritic rocks of the second suite. This breccia zone is enriched in Cu-Fe-Ni sulphides and has become the principal site for concentration of PGE, gold and silver. On a whole Pd dominates over Pt in the sulphide-bearing Shankar chromite lode and the adjacent orthopyroxenite as well as gabbro in this breccia zone. The chromite-sulphide association is the most enriched part for PGE, gold and silver. Ag is positively correlated with Pd. The breccia zone which was developed prior to the gabbroic emplacement into the chromiferous ultramafics, represents a sulphide-rich metasomatic zone leading to maximum concentrations of PGE, Au, Ag in this zone alongwith formation on various sulphides, oxides and silicates.

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016973    (Paleontology Laboratory, Dr. B.R. Ambedkar Regional Geoscience Laborat, , ) : Calcareous nannoplankton and formaniferal biostratigraphy of ypper cretaceous and paleogene subsurface sequences of Kharatar well-C, Jaisalmer, Rajasthan. Geosci J 1998, 19(2), 145-69.

Subsurface Parh Formation (Upper Cretaceous; Turonian-Santonian) of Kharatar well-C (KT well-C) is very rich in foraminiferids and its upper part is found to contain Watznaueria barnesae in abundance. Three foraminiferal zones: (1) Helvetoglobotruncana helvetica-Dicarinella imbricata Assemblage-zone (Turonian); (2) Marginotruncana renzi zone (Coniacian) and (3) Rosita fornicata zone (Lower Santonian) have been delineated in ascending order in the Parh Formation of KT well-C. For the first time the age of the Parh Formation has been extended to the lower part of Santonian due to the occurrence of Rosita Fornicata. A fairly good assemblages of the insitu and reworked calcareous nannoplankton have been recorded from the subsurface Sanu Formation (Paleocene). The major part of the Khuiala Formation (Lower Eocene) has not yielded calcareous nannoplankton. However, its lower part is part is very poor in calcareous nannoplankton. The intermittent intervals of the Bandah Formation are found to contain calcareous nannoplankton.

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015897   Valdiya K S;Rajagopalan G (Geodynamics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560 064) : Large palaeolakes in Kaveri basin in Mysore plateau : late quaternary fault reactivation. Curr Sci 2000, 78(9), 1138-42.

Late Quaternary movements along the faults that demarcate tectonic boundaries of the N-S trending terranes of Biligirirangan and Closepet Granite in the Southern Indian Shield caused ponding of the River Kaveri and its tributaries Suvarnavati, Kabini and Shimsha of the Mysore Plateau. The resulting large lakes stretched tens of kilometers upstream in their valleys. Approximately 10 m thick black carbonaceous clay, characterized by prolific calcareous nodules including rhyzocretions in the top horizon, and covered locally by overbank fine sediments in floodways, represents the lakes that came into existence in the Late Pleistocene and lasted until Late Holecene. Subsequent fault movements were responsible for vertical displacement and attenuation of the lacustrine sediments. On-going movement is indicated by stream ponding in some segments and accelerated erosion of the elevated blocks.

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015896   Singh A D;Schiebel R;Nisha N R (Department of Marine Geology and Geophysics, School of Marine Sciences, Cochin University of Science and Technology, Cochin-682 016) : Occurrence of pteropods in a deep eastern Arabian Sea core: neotectonic implications. Curr Sci 2000, 78(9), 1142-4.

Pteropod shells (aragonitic) at 100, 200, 270-277 and 470 cm sediment depths in a core (EAST) recovered from 3820 m deep water from the eastern Arabian Sea. Ages of the four stratigraphic levels showing pteropod presence are estimated as 29, 52, 70-72 and 127 kyr. In normal circumstances microfaunal assemblages of this core are expected to be devoid of pteropod shells because the site is situated far below (<126> 3.5 km) the Aragonite Compensation Depth. Therefore, the recorded pteropod shells are exotic to the location and may have been transported from the shallower depths by the turbidity currents. The plausible reason for the preservation of aragonitic shells at such greater depth appears to be quick burial of pteropods resulting from large-scale vigorous slumping triggered by neotectonic activity.

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015895   Kant Y;Sharma M C;Ghosh A B;Gupta P K;Krishna Prasad V;Badarinath K V S;Mitra A P (National Remote Sensing Agency, Department of Space, Government of India, Balanagar, Hyderabad-500 037) : Impact of aerosol optical depth on UV-B radiation - a case study over Eastern Ghats. Indian J Radio Space Phys 2000, 29(2), 71-80.

Field experiment has been conducted in East Godavari district (Eastern Ghats) of Andhra Pradesh to investigate the relationship between aerosol optical depth and UV-B intensity over the biomass burning areas. Three sites were chosen for the measurements, in close horizontal proximity, to measure the aerosol optical depth, the UV-B intensity and erythemal doses. The Microtop-II sunphotometer was established at the sites to measure aerosol optical depth at five different wave-lengths. The UV-B instruments, erythemal probe and UV-B biometer were used to measure the intensity of UV-B radiation and minimum erythemal dose. The study focuses on the attenuation of UV-B intensity and variation with respect to aerosol optical depth values over biomass burning areas. The comparison of the diurnal variation of the UV-B intensity over the burning sites with the ambient level reveals that there is reduction in the UV-B intensity peak during biomass burning phases. This reduction in UV-B intensity had been found to be 49%, 35% and 53% over the three different sites selected. An attempt has been made to deduce the fluctuations in the selective absorption of ozone at 297.5 nm in terms of the variability of UV-B intensity at 297.5 nm. The experiment showed the UV-B intensity restoring to its normal values after the biomass burning revealing that the variation in atmospheric ozone was not very large.

015894   Dash P;Singh R P;Voss F (Department of Civil Engineering, Indian Institute of Technology, Kanpur-208 016) : Anomalous stress pattern in Chamoli region observed from IRS-1B data. Curr Sci 2000, 78(9), 1066-70.

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014936   Vetha Roy D;Chandrasekar N;Kumaresan S; Udayanapillai A V;Rajamanickam G V (Department of Chemistry, Scott Christian College, Nagercoil-629 003) : Distribution of carbonate and organic carbon in the sediments of Tambraparani delta, Tamil Nadu. Envir Ecol 0000, 17(4), 1999.

Contents of organic carbon and calcium carbonate were estimated from the surface sediment of Tambraparani delta. Sediment samples located near the river mouth showed high carbonate content and low organic carbon. The sediments around the zone of mangrove vegetation and industrial waste disposal area showed high value of organic carbon. The carbonate dilution was pronounced in the industrial waste disposal area and sewage channels. Sand and silty sand were spread over the study area with patches of clayey sand and silty clay.

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014935   Tyagi R N (NO, ISRO Satellite Centre, Bangalore-560 017) : IRS-P4 mission. Curr Sci 1999, 77(8), 1033-7.

IRS-P4 in the series of Indian Remote Sensing Satellites (IRS) is designed to serve the applications in the area of oceanography and atmospherics. Ocean Colour Monitor (OCM) and Multi-frequency Scanning Microwave Radiometer (MSMR) are the two payloads. The OCM operates in the visible and near infra-red bands and MSMR in microwave bands. These instruments will sense such important geophysical parameters as, chlorophyll content, yellow substance and suspended sediments in ocean waters; sea surface temperature, sea surface winds, water vapour in an atmospheric column and water content in clouds. The orbit is selected such that a systematic coverage of the whole globe is achieved once in two days. The satellite mainframe derives its heritage from the earlier IRS mission. IRS-P4 along with the two co-passengers was successfully launched on 26 May 1999 by PSLV-C2 from Sriharikota, Subsequently, it has been operationalized after on-orbit checkout. The data from both the payloads is regularly received and processed by National Remote Sensing Agency (NRSA) at Hyderabad. Various aspects of IRS-P4 mission including satellite mainframe, payloads and ground segment have been described.

014934   Suresh R;Sivaramakrishnan T R (NO, Regional Meteorological Centre, Madras-600 006) : Variability of monsoon performance over Tamilnadu. Vayu Mandal 1997, 27(3-4), 31-5.

Statistical study of the performance of the Southwest (SW) and Northeast (NE) monsoons has been carried out for the period 1901 to 1985 for the Tamilnadu state as a whole. The relative performance of monsoons has been critically analysed for various districts for the period from 1965 to 1993. The distribution of rainfall has been tested for normality and statistical tests obeying normality and non-parametric tests for non-normal distributions have been applied to find out significance, trend etc. The probability analysis has been carried out to pick out the best and least chance to have Normal or Excess monsoon which is of prophylactic value to water managers and administrators for socio-economic planning. The occurrence of cyclonic disturbances over Bay of Bengal has been analysed to account for the rainfall variability between monsoons.

014933   Suresh R (NO, Regional Meteorological Centre, Chennai-600 006) : Adaptive filter algorithm to issue short range forecast of temperature and pressure over an Inland airport station. Vayu Mandal 1997, 27(3-4), 14-19.

Method of generalised adaptive filtering has been used to forecast the surface temperature and pressure, 3 hours ahead, over Trichy airport in Tamilnadu. The forecast efficiency is compared with climatology and persistency method and other univariate models. The adaptive filtering technique proved to be more efficient than other methods which are operationally viable in forecasting the temperature and pressure with absolute errors with in 1 deg C and 1 hPa respectively. In the absence of products of a foolproof limited area fine mesh (grid) model (being made available at every airport/aerodrome meteorological office to cater to the aviation needs) the adaptive filtering model can conveniently be used.

014932   Sudhakar Rao G;Sarkar M B;Chakraborty D D (NO, Food Meteorological Office, Hyderabad) : Semi-quantitative precipitation forecast for Teesta basin by synoptic analog method. Vayu Mandal 1997, 27(3-4), 36-9.

Method to issue semi-quantitative precipitation forecast for Teesta basin by synoptic analog method has been developed based on analysis of 10 years data (1985-1994). The results are applied for the realised Average Areal Precipitation (AAP) for Teesta basin for the flood season of 1995 for the analog synoptic situations and found that the statistical analog procedure gives a good idea for predicting AAP semi-quantitatively for Teesta basin.

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014931   Singh D (Department of Physics, Government Science Autonomous Post Graduate College, Bilaspur-495 006) : Effect of soil moisture on microwave scattering for remote sensing. Sadhana 1999, 24(6), 485-93.

Remote sensing is to design space borne microwave sensors to sense a target and derive useful geophysical parameters. For this purpose, the knowledge of the target characteristics must be obtained through ground based remote sensing. Soil has been taken as the target. Various percentages of gravimetric oil moisture (mg) have been taken for establishing its relation with the scattering coefficient (σ0) for both like polarizations at X-band frequencies. A linear model has been developed for correlating these two variables (i.e.mg and σ0). Using this model, regression analysis has been done for obtaining different regression parameters and predicted values. Treating measurements from bare smooth soil fields with different soil moistures, the data were analysed to examine the effect of soil moisture on scattering coefficient (σ0) at 9.50 GHz frequency in X-band. The scattering coefficient increases with increase in soil moisture content. Different regression parameters have been obtained, which show that the best look-angle is at 25° for HH-pol and 60° for VV-pol for observing σ0 from bare moist soil. Data analysis indicated that the basic cause and effect relationship between the sensor measurements and soil moisture can be extrapolated from theory and small-scale tests to larger resolution elements observed by the sensing aircraft.

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014930   Sikdar P K;Bhattacharya P (NO, Centre for study of Man and Environment, CK-II, Sector 2, Salt Lake City, Calcutta-700 091) : Geochemistry of grounwater of Jhalda-II Block, Puruliya district, West Bengal. J appl Hydrol 1999, 12(1), 10-22.

Detailed geochemical investigation of the groundwater samples from Jhalda-II block Puruliya District, West Bengal was carried out. In general, the groundwater is fit for drinking except in a localised patch in and around Chitarpur where both TDS and chloride concentrations are above the Indian standard for drinking water. The Sodium Absorption Ratio (0.05 - 1.50), per cent Sodium (2.08 - 41.35) and electrical conductivity (195.2 - 1389.3 μS/cm) reveal that groundwater is moderately suitable for irrigation. The use of this groundwater for irrigation will not lead to any sodium hazards but may cause medium to high salinity hazards on prolong use. The groundwater can be categorised with four hydrochemical facies. Varimax-rotated factor analysis based on eleven chemical parameters indicates that (i) the processes which may have controlled the geochemistry of groundwater are: local groundwater flow system; residence time of groundwater within the fractures of the hard rock aquifer; regional groundwater flow system and biogenic or organic control on the pH of groundwater and groundwater samples can be categorised into three chemical zones : Zone 1-HCO3 dominated facies (Facies 1), TDS concentration low; Zone 2-HCO3 - Cl dominated facies (Facies 2) and Cl-HCO3 dominated (Facies 3), TDS concentration moderate (Facies 2); and Zone 3 - Cl dominated (Facies 4), TDS concentration high.

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014929   Sawant P T (NO, Walchand College, Solapur, Maharashtra) : Ground-water potential of Bhogawati River Basin, Solapur district, Maharashtra. J appl Hydrol 1999, 12(1), 1-9.

Lithological, geomorphological, structural aspects alongwith the resistivity soundings are successfully used in recommending suitable sites for dug-wells, bore-wells and dug-cum-bore-wells for drinking water and agriculture purpose. Based on the detailed exploration work carried out in the basin, three favourable zones for groundwater exploitation have been identified viz; at 10-15 m. 65-90 m. and 20-25 m. depths. Out of the three paying zones, two promising lower ones, are recommended for exploitation by using submersible pumps at places fixed with timers while, the upper one can be tapped by using double electric motor linkage in the dry dug-wells or by using jet pump to meet the drinking water supply in the residential areas. The study has revealed that the potential areas cover about 40% of the basin, poor ground-water potential areas covers 20% of the area in the basin. The zones with resistivity value ranges form 35 to 55 ohm-m. appears to be a good aquifer zone in the basin.

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014928   Sankaragururaman D;Moses Edwin J;Ayyadurai D (NO, Institute of Remote Sensing, Anna University, Chennai-600 025) : Integrated approach for groundwater development of Nambiyar watershed of Tirunelveli district using remote sensing data. J appl Hydrol 1999, 12(1), 23-9.

Watershed management study is a long term project and its ultimate aim is the comprehensive development of watershed which results in better productivity, by proper utilisation of groundwater and overall welfare of the people living in that area. Quantitative and qualitative study have been made and they have been correlated with remote sensing data on 1:50,000 scale. This integrated studies involving geomorphological, lithological and structural investigation followed by hydrological and hydrogeochemical exploration led to the identification of good groundwater potential zones in Nambiyar watershed. An attempt has been made to enumerate the various aspects of watershed management for groundwater development by giving special emphasis to the hydrogeological studies required to be integrated, for efficient management and for formulating watershed management model.

014927   Saifuddin;Iqbaluddin (Remote Sensing Applications Center for Resource Evaluation and Geoengi, 7-B, Old Shibli Road Aligarh Muslim University, Aligarh-202 002) : Migration of Yamuna river from Mahabharata period to the present - a remote sensing view. J Indian Soc Remote Sens 1999, 27(2), 129-32.

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014926   Ranjan G;Singh B;Charan H D (Department of Civil Engineering, University of Roorkee, Roorkee) : Experimental study of soft clay reinforced with sand-fiber core. Indian Geotech J 1999, 29(4), 281-91.

Results of a series of triaxial compression tests on soft clay samples reinforced with a central sand-fiber core, to study the influence of relative core area (i.e. the ratio of area of sand-fiber core to that of the sample), amount of fibers in the core and confining stress on the strength of soft clay. Analysis of test data indicates that the strength of soft clay increase significantly with the introduction of sand-fiber core. The strength of composite clay increases with increase in relative core area, amount of fibers in the core and confining stress. A comparison of improvement in strength of soft clay treated with granular core and sand-fiber core reveals that the sand-fiber core is more effective in improving the strength of soft clay.

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014925   Ramasamy S M;Balaji S;Kumanan C J (Centre for Remote Sensing, School of Earth Sciences, Bharathidasan University, Tiruchirappalli-620 024) : Tectonic evolution of early precambrian South Indian shield (Rocks) using remotely sensed data. J Indian Soc Remote Sens 1999, 27(2), 91-104.

Interpretation of satellite imagery of part of South India falling South of 15 degree North latitude shows that the regional anticlines, synclines, domes and basins of the Precambrian group of metamorphites are aligned in three major hill ranges/domains such as Chitra-durga domain in the north, the Mangalore-Ootacamund-Bangalore domain in the centre and the Cochin-Cape Comorin-Madurai-Chittoor domain in the south. These hills are crescent shaped with their axes of elongation oriented in NNW-SSE direction. The lineaments with ENE-WSW, NE-SW/WNW-ESE and NNW-SSE azimuthal frequencies respectively exhibit extensional, shear and release geometries. Such deformational fabric shows that the tectonic evolution of South India was controlled by two major compressive forces, the first one aligned in N-S direction and the second in ENE-WSW direction.

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014924   Rama Rao P V;Sudhakar Rao G;Seshu D (NO, Meteorological Office, Hyderabad-500 016) : Flash floods over South coastal Andhra Pradesh and Rayalaseema in October 1996. Vayu Mandal 1997, 27(3-4), 47-9.

Parts of Andhra Pradesh experienced high floods during October, 1996. A brief history of the synoptic situation, associated weather & rainfall, resultant floods and loss of life & property is given in this article. Brief damage report from the Relief Commissioner, Government of Andhra Pradesh and isohyetal maps of the rainfall are also given.

014923   Raghunath R;Sreedhara Murthy T R;Raghavan B R (Department of Marine Geology, Mangalore University, Mangalagangotri-574 199) : Aquifer parameter evaluation of Nethravathi river basin, Karnataka state, India. J appl Hydrol 1999, 12(1), 46-51.

In Nethravathi river basin, Karnataka (India), using drawdown and recovery data of 16 dug wells, the aquifer transmissivity, storage coefficient, specific capacity, optimum yield and time for full recovery values of dug wells have been calculated. Thematic maps depicting the above mentioned aquifer parameters show that the storage coefficient and total time for full recovery increase towards the eastern part of the basin (towards Western ghats) and specific capacity and optimum yield decrease towards the eastern part of the basin. There are two patches (in north-western and south-eastern quarter of the basin) characterised by high values of specific capacity and transmissivity and relatively high values of optimum yield and storage coefficient with fairly low total time for full recovery.

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014922   Radha Krishna M;Mahadevan T M (Department of Marine Geology & Geophysics, Fine Arts Avenue, Cochin University of Science & Technology, Cochin-682 016) : Seismogenesis and deformation in the Deccan Volcanic province, Peninsular India. Curr Sci 2000, 78(6), 734-42.

Strain rates for events of M≥4.0 and/or I≥5 in the time span 1750-1997 AD (247 years) are the highest for the Kutch seismic domain, being 3.5x10^-8/yr. They are similar for the BARS and SONATA belt being 1.2-1.5 x 10^-11/yr, and are lower by an order of magnitude (1.7-4.2 x 10^-11/yr) in the Godavari and Saurashtra domains which have a more closely comparable continental crustal structure. The moment rate tensors estimated for BARS indicate the dominance of N-S compressional stresses. In view of preferred N-S orientation of BARS, tend to believe that ridge push forces along the mid-Indian Ocean ridges may have a dominant contribution to the stress field of this region matching the Himalayan back thrust. The difference in moment release pattern between the BARS and the SONATA belt is probably due to the contrasting deep continental structure of these regions. The uncertainties in estimation of seismic moments, particularly for historical events, and other assumptions render the above conclusions tentative. However, differences of one or two orders of magnitude in strain rates and concordance of observations with geological and stress field measurements enhance their credibility.

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014921   Paul A K;Patra R N;Khaoash S;Mohanty J K (Dept. of Geology, Utkal University, Bhubaneswar) : Sulphide mineralisation in Boula-Nausahi igneous complex, Orissa, India. SGAT Bull 2000, 2(1), 57-64.

Sulphide mineralisation is ubiquitous in the Breccia Zone of the Shankar-Ganga composite lode and is sporadic in the serpentinised ultramafic rocks of the Boula-Nausahi Igneous Complex. Pyrrhotite, chalcopyrite, pentlandite, pyrite with minor to trace amounts of millerite, mackinawite, cubanite, bornite, heazelewoodite and bravoite are documented from this belt. The sulphide minerals exhibit vermicular intergrowth, exsolution intergrowth and replacement textures. Two types of sulphides, primary and secondary ascribed to two different genetic models have been suggested.

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014920   Neelakantan T R;Pundarikanthan N V (Centre for Water Resources, Anna University, Chennai-600 025) : Design of Chennai water supply system - a linear decision rule analysis. J appl Hydrol 1999, 12(1), 37-45.

Chennai is a water starved city, where to augment the supply construction of additional reservoirs are planned along with bringing water from Krishna river flowing 500 km away. The existing system and the problems are described along with the proposals. Analyses the dependable flow and the effect of construction of additional reservoirs with Linear Decision Rule and Linear Programming application.

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014919   Nandargi S;Dhar O N (NO, Indian Institute of Tropical Meteorology, Pune-411 008) : A study of floods in the Ganga and its sub-basins. Indian J Pwr River Valley Dev 1998, 48(5-6), 85-90.

Floods that have occurred in the main Ganga river and its northern and sourthern tributaries during the 10-year period from 1987 to 1996 have been discussed. Flood data recorded at 18 gauge/discharge (G/D) sites on the main Ganga river and 42 G/D sites on its tributaries have been analyzed with a view to find out which tributaries and which G/D sites experienced frequent floods during the monsoon months of different years.

014918   Nageswara Rao G (Department of Meteorology and Oceanography, Andhra University, Visakhapatnam) : Year to year variations of monsoon rainfall and the available water resource in Godavari River basin. J appl Hydrol 1999, 12(1), 52-8.

Year to year variations of the southwest monsoon (June to September) rainfall over one of the central Indian river basins, `Godavari' and their impact on the availability of water resource in the basin are studied by using the rainfall and runoff data for 30 years (1962-91). It is observed that while the monsoon rainfall in the basin varies from 72% to 136% of its mean, the corresponding seasonal runoff varied from 36% to 146% of its mean. It is further observed that the `availability of seasonal runoff', i.e., the ratio of runoff to the rainfall in the basin, also varies largely from year to year with the associated rainfall in the basin. During the excess rainfall years, the availability of seasonal runoff is observed to be as high as 48% of the monsoon rainfall in the basin, while it is as low as 13% during the deficient rainfall years. The variations in the seasonal runoff availability are further observed to be due to the large year to year variations in the number of floods in the river. It is found that the seasonal runoff and its availability have stronger relationships with the number of flood-days than with the associated seasonal rainfall.

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