Identification of Artificial Recharge Sites for Nand Samand Catchment

Security of groundwater is widely regarded as a serious impediment to India's economic and social progress. According to the Central Ground Water Board's (CGWB) assessment, India's groundwater tables are plummeting at an alarming rate, with reserves in some regions reaching critical levels. Unregulated groundwater use in southern peninsular India has also resulted in excessive extraction, lowering the 'critical' threshold. With over 30 million groundwater structures in use, India is on the verge of a disaster of over-extraction that will leave 60% of all aquifers in critical condition within the next two decades. To resolve the issue, a variety of renewable groundwater solutions must be implemented. Artificial recharge is a procedure that augments groundwater at a pace that is significantly greater than the rate of replenishment under natural conditions, which may give a solution. The current study is for the Nand Samand catchment in the district of Rajasthan. The investigation of artificial groundwater recharge sites is being conducted using an integrated Remote Sensing and Geographic Information System (GIS) approach. Thematic maps such as topographic elevation, post-mosoon groundwater level, recharge, slope, transmissivity and soils map are created, and weighted overlay analysis is used to identify areas suitable for artificial recharge. Keywords: Nand Samand catchment, artificial recharge zone, thematic map, remote sensing, GIS

Bharat mein 1990-1999 ke dauraan shushkata visangatiyon ka kshetreey avem saamayik vishleshan

Aridity Anomaly Index (AAI), based on Thornthwaite’s water balance technique, has been used to identify the extent and persistence of aridity anomalies over 33 sub-divisions of India during a period of 10 years from 1990 to 1999. Regional and temporal analysis has been carried out to identify the areas and periods of intense and prolonged persistence. This study has shown that 1992 was worst hit by the aridity conditions, which emerged in 5 or more fortnights. All sub-divisions of north India were affected by moderate aridity during 1990, 1992-94 and 1999. Similarly, all sub-divisions of peninsular India were influenced by moderate aridity during 1991, 1993 and 1999. Severe aridity appeared in all sub-divisions of peninsular India during 1990. The duration of severe aridity was less than that of moderate aridity during all years. Moderate and severe aridity appeared simultaneously in 5 or more fortnights in maximum 9 sub-divisions in 1992 and occurred during maximum 5 years in Madhya Maharashtra. Moderate aridity in 5 or more fortnights emerged each year during 1990 to 1999 in coastal Andhra Pradesh. In 1991, maximum 55% sub-divisions were affected by severe aridity in 9th fortnight, whereas Saurashtra & Kutch was affected in 1996 and north Interior Karnataka in 1999 during maximum 7 fortnights. In the year 1992, maximum number of sub-divisions under moderate and severe persistence was 70% and 24% respectively. In north India, moderate persistence appeared in east Rajasthan in all nine years except 1996, with its longest duration of 8 fortnights in 1995. West Madhya Pradesh, in peninsular India, was affected by moderate aridity during 7 fortnights in each year during the period of study from 1990 to 1999.

Estimation of monsoon wind characteristics in India

A detailed statistical analysis of monthly average wind speed data of monsoon period (June-September) for the year 1921-90 for 57 stations spread all over India have been reported. Probability densities, average wind speeds, standard deviations, kurtosis and skewness of wind speed frequency distribution for each station have been worked out. Histograms depicting relative frequency distribution of average wind speeds have also been prepared. It is observed that the different histograms do not exhibit any similarity among themselves indicating thereby that no single distribution is uniformly applicable for all the stations. It is also seen that the average wind speeds during monsoon period over major part of India varies from 7 to 14 kmph. Further, at most of the stations average monsoon wind speed is generally higher than average annual wind speeds. It is also noted that most of the time the wind speed exceeds 10 kmph in coastal regions of Gujarat and southern parts of the peninsular India. The information generated is of multi fold application such as (i) Identification of sites suitable for installation of Wind Energy Conversion Systems (ii) Development of Driving Rain Index and (iii) Design of buildings for creating comfortable environment indoors.

Summer monsoon low pressure systems over the Indian region and their relationship with the sub-divisional rainfall

In the present paper performance of the monthly sub-divisional summer monsoon rainfall is studied in association with the position of the Low Pressure System (LPS) over the Indian region. Existence of the LPS over a particular location increases the rainfall activities in certain parts of the country while decreases in some other parts. For this study, the Indian region (5°-35° N and 60° -100° E) is divided into 5° Lat. ´ 5° Long. grids. The duration of LPS is taken in terms of LPS days with respect to the location of LPS in a particular grid. Monthly total number of LPS days in each of the grids are computed during the summer monsoon season, June to September for the period 1891 – 1990. Maximum number of LPS days (more than half of the total) are observed in the latitude belt between 20°-25°N. The percentages of total LPS days in this area are higher in July and August which are peak monsoon months as compared to June and September. When there is a LPS are in the area 20°-25° N and 80°-90° E, there is significant increase in the rainfall activities in the sub-divisions along mean monsoon trough while northeast India and southeast peninsular India experience significant decrease in rainfall in the months of July and August. Owing to the movement of LPS from east to west through central India, most parts of the country, excluding northeast India and south peninsular India get good rainfall activity. Correlation coefficients between monthly LPS days over the different grids and monthly sub-divisional rainfall are computed to study the relationships. The performance of sub-divisional rainfall mostly related with the occurrence of LPS in certain grid- locations. The correlation field maps may give some useful information about rainfall performance due to LPS in a particular grid locations.

Aboveground Biomass Stockpile of Trees in Vallanadu Blackbuck Sanctuary, Peninsular India

A forest tree inventory study was conducted in Vallanadu Black buck sanctuary, Tuticorin. The current study was conducted to assess tree density, species richness, basal area (BA) and aboveground biomass (AGB) stockpile. The study area has been classified as Southern Thorn Forest (SFT). One hundred square plots (total area 1 ha), each 10m × 10m (100 m2 each) laid randomly across study area. All live trees with ≥5 cm diameter at breast height (DBH) measured at 137 cm above the ground. As the whole, 1335 individual trees ≥5cm DBH recorded. A total number of 18 species recorded from 14 genera and 11 families in study area. The family Mimosaceae has maximum number of species (7 species) followed by Rhamnaceae (2 species), while 9 families had just single species’ each. The total basal area recorded was 22.046 m2 ha-1, while, the mean wood density (WD) of trees estimated as 0.70±0.093 g cm-3. Total amount of 50.065 Mg ha-1 present in STF. The contribution of different species in terms of total AGB varied significantly. Commiphora berryi stocked 45.13% (22.588 Mg ha-1) of AGB followed by A. planifrons (23.31%, 11.669 Mg ha-1), A. mellifera (7.233%, 3.621 Mg ha-1), whereas remaining 15 species collectively stocked 24.327% (12.187 Mg ha-1) AGB. The STF had a large number of trees compared to some dry forests within Tamil Nadu. Southern Thorn Forest endowed with a moderate number of trees species. Aboveground biomass stockpile of trees is comparable with the range recorded from Indian dry forests. The study area experiences lesser mean annual rainfall and >6 months dry season. Further, endowed with short-bole and smaller leaved trees, hence stocked a relatively lesser AGB in trees.

An insight into the severe floods in India during 2005, 2006 & 2007

In this paper severe flood during South West monsoon seasons of 2005, 2006 & 2007 have been identified with the related synoptic features. A total of 22 states reeled under severe floods during 2005, 2006 & 2007. In the south peninsula only Karnataka and Kerala were affected by severe floods. During 2006 & 2007 severe floods continued for a longer period and affected many states where as during 2005 severe floods affected most of the states except peninsular India but they continued for short periods comparatively.Formation of excess No’s of low pressure areas and depressions in the Bay of Bengal during July, Aug and Sept 2006, in succession , and their WNW movements upto M.P. and east Rajasthan caused severe floods in Gujarat, Maharashtra, Rajasthan, Madhya Pradesh, Chattisgarh, Orissa and Andhra Pradesh for a longer period i.e. from 28 July to 12 September 2006. During 2007, Shifting of monsoon trough, presence of secondary monsoon trough and trough in westerly, caused severe floods in most of the North eastern states from 12 July to 10 October 2007.

Elotespora mumbaiensis sp. nov.: A novel species of Anamorphic Ascomycota reported from Peninsular India

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