Browsing by Author "Bhardwaj, A."

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Geospatial technology applied to spatiotemporal assessment of Harike Wetland, Punjab
(Blackwell Publishing, 2017) Bhardwaj, A.; Najar, G.N.; Pandey, P.
The Harike Wetland situated in Punjab is a Ramsar site and a wetland of national importance. The present study was undertaken to assess the spatiotemporal dynamics of the wetland on the basis of geospatial technology and ground-based studies. Landsat images for the years 2002 and 2014 were acquired from the United States Geological Survey and classified digitally to generate landuse/land cover maps involving four classes (water, grassland (including water hyacinth), agriculture, built-up (settlement), barren land). The total area of the Harike Wetland was found to be 8023.68?ha. Water sampling at eleven sites was carried out and evaluated for physicochemical parameters. The water quality at several sampling points was found to be severely degraded. Change detection analysis revealed the submerged area (area under water) and grassland (including water hyacinth) had decreased over the past 12?years, whereas that area under agriculture and built-up land has increased, indicating a shrinkage in the total wetland area. The present study also indicated that the near-infrared band is a good indicator of water quality parameters, as indicated by the significant positive correlation between the near-infrared band and relevant water parameters. Because the wetland is important from both an ecological perspective and economic perspective, regular monitoring is recommended, for which geospatial technology has proven to be very useful. ? 2018 John Wiley & Sons Australia, Ltd
Response of diatoms to water quality in Khajiyar lake, Himachal Pradesh
(EM International, 2016) Bhardwaj, A.; Chauhan, R.
The present investigation was carried out to study the presence, abundance and distribution of diatoms in relation to the water quality of Khajiyar Lake, Himachal Pradesh during April, 2011 to January, 2012. The lake is about 2000 m above sea level and is situated at 32? 32? 53? N and 76? 3? 34?E. Surface water samples were collected from the Khajiyar lake for six months over the year in the month of April-May in summers, July-August during rainy season and December-January in winters. The diatoms presence, abundance and distribution were found to be greatly influenced by the physico-chemical regime of the lake. The diatoms density showed highly significant and positive relationship with conductivity (r = 0.869, p<0.01), and chloride (r= 0.857, p<0.01) and positive relationship with nitratenitrogen and total phosphate-phosphorus. The higher values of free carbon dioxide (11.0-26.8 mg/L), chloride (20.2-33.1mg/L), nitratenitrogen (0.098-0.485mg/L), total phosphate-phosphorus (0.62-2.32mg/L), very low percentage of oxygen indicators species and the presence and abundance of pollution indicator diatom species such as Diatoma vulgare (5%), Navicula gracilis (24%), Navicula gibba (8%), Pinnularia nobilis (12%), Nitizschia sigmoidea (3%), Gomphonema geminatum (23%), Frustulia rhomboides (2%), Tabellaria fenestrata (2%) and Cylinderotheca gracilis (4%) throughout the investigation indicated highly deteriorated water quality of the lake ecosystem. Study thus demonstrated response of diatoms to changing water quality and their role as bio-indicators.
A spatio-temporal water quality assessment of the Beas and Sutlej Rivers at the Harike Wetland: A Ramsar site in Punjab, India
(Blackwell Publishing, 2017) Najar, G.N.; Bhardwaj, A.; Pandey, P.
Lakes play a vital role in regulating water storage, flow of river water, and ultimately maintaining a balanced ecosystem. Spatial and temporal variations in physicochemical parameters of water in Harike Wetland, a Ramsar site in the northwestern state of Punjab, India, were studied. This study was conducted on a monthly basis from January to December 2015. The water quality was studied at ten locations from sites 1 to 10 upstream, central and downstream from Harike Lake for ten physicochemical parameters, including temperature, pH, electrical conductivity, turbidity, dissolved oxygen concentration biological oxygen demand, nitrate and phosphate concentrations and salinity. The findings of this study revealed that, except for temperature and pH, all parameters exhibited relatively higher values for the Sutlej River, compared with the Beas River, with sampling sites 5 to site 7 exhibiting intermediate results. The mean seasonal temperature variations ranged from 16.9 to 26.6??C, the pH from 7.7 to 8.2, electrical conductivity from 223 to 303??S cm?1 and TDS concentration from 148.7 to 180.4?ppm. Correlation analysis was conducted to assess the relations between the variables. The electrical conductivity exhibited a high positive correlation with salinity and biological oxygen demand, whereas it correlated negatively with the dissolved oxygen concentration. Box?and whisker plots were also plotted for the study results to better examine the data distribution. ? 2017 John Wiley & Sons Australia, Ltd