Exceptional heavy rainfall over Ajoy, Mayurakshi and Kansabati catchments and QPF verification during flood season of September 2009

Ajoy, Mayurakshi, Kansabati are three important river catchments of West Bengal and Jharkhand state, received very heavy rainfall during two consecutive days of flood season in the month of September 2009. The contribution of heavy rainfall & combined discharges from Damodar Valley Corporation (DVC) reservoirs during the period of heavy rainspells over these catchments enhanced flood situation in some districts of West Bengal. The synoptic features based on weather charts, cloud imageries of satellite and radar pictures have been taken to analyse. The realized areal average precipitation (AAP) as per rainfall recorded at 0300 UTC of next day have also been taken to verify the quantitative precipitation forecast (QPF) of 6&7 September 2009.

A Synoptic analogue model to issue QPF over Gangetic West Bengal and adjoining Jharkhand

In this study the Areal Average Precipitation (AAP) data for each day over each of the six catchments of Gangetic West Bengal (GWB) and adjoining Jharkhand namely river catchments of Mayurakhshi, Ajoy, Kansabati, Damodar, Barakar and Lower Valley of Damodar Valley Corporation during monsoon season for 25 years from 1990 to 2014 have been analyzed by grouping the AAP in three different ranges (11-25 mm, 26-50 mm, 51-100 mm and more), excluding Mainly Dry and 01-10 mm. The associated main synoptic features viz., trough at mean sea level, low pressure area, well marked low pressure area, cyclonic storm and cyclonic circulation for each day and their location with respect to the river catchments, viz., over the catchment, neighbourhood of the catchment (within 200 km South or North) and outside the catchment (more than 200 km South or North) have also been studied. The association of AAP ranges over six catchments with different categories of synoptic features has been examined. The distribution of percentage frequency of AAPs associated with the category of synoptic feature for the period 1990 to 2014 has led to development of a Synoptic Analogue Model (SAM) for issue of Quantitative Precipitation Forecast (QPF). The results obtained from SAM have been verified for rainfall data and calculated AAPs of monsoon season of 2015 over all the catchments and different skills scores also presented in this study.

Assessment of Dam-Induced Changes in Ecogeomorphological Behaviour and Fluvial Functionality in the Damodar River, West Bengal, India

Anthropogenic interventions in the form of dams and barrages often alter the fluvial functionality and ecogeomorphological (geomorphology, hydrology, and ecology) behaviour of the river systems. The present work examines the environmental flow, channel metamorphosis, and fluvial functionality of Damodar River in the context of Damodar Valley Corporation (DVC) dams and development. The structural (dams, barrages, weirs, etc.) and non-structural (urban-industrial and agricultural disposal with effluents, sand mining, etc.) interventions hinder the ecological functionality of the river. This study portrays that the eco-geomorphological behaviour and fluvial functionality of the river have changed due to flow alteration and diversion by dams and barrages and due to the urban-industrial and agricultural growth in the basin area. These changes have affected riverine ecological integrity. The ecological functionality level of this study area ranges from 85 to 181 i.e. poor to good-fair. The ecological functionality level in sample channel sections (i.e., immediate upstream and downstream of Durgapur Barrage) is poor, and the value ranges from 61 to 100 due to the hydrological impact of the barrage and the Durgapur urban-industrial belt. This assessment work would help to restore the fluvial environment for humans as well as riverine biota.

INSIGHTS OF SHALE GAS EXPLORATION AND DEVELOPMENT IN INDIA: REVIEW

Encouraging results of shale gas production in different countries viz. USA, China and Australia, India is also inspired to explore shale gas resources, which may not only support meeting the growing energy demand but also assist to reduce the import of hydrocarbons. This paper aims to review the current status of shale gas exploration programs in various sedimentary basins in India for a better understanding of the prospect of shale gas. The signicant thickness of organic-rich shale deposits is reported in various Gondwana and Tertiary sedimentary basins including Damodar valley, Krishna-Godavari, Cauvery, Cambay, Assam-Arakan, Ganga and Vindhayan basins. The geochemical properties like TOC and thermal maturity, Organo-inorganic mineral compositions, pore-network system, and depth of shale deposits are favoring the potential prospect of shale gas in India. Several agencies namely EIA, ONGC, USGS, Schlumberger, and CMPDI reported enormous resources of shale gas in its various sedimentary basins.