T. V. Ramachandra 1, *, B. Alakananda 1, Ali Rani 2 and M. A. Khan 2
1 Energy & Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore – 560 012, India 2 K K English High School, Varthur, Karnataka (India) E-mail: cestvr@ces.iisc.ernet.in, alka@ces.iisc.ernet.in METHODSWater quality analysis Water samples (triplicates) were collected from three sites viz. inlet (12°56'35.99"N lat. and 77°44'5.32"E long.), south-outlet (12°56'43.91"N lat. and 77°44'48.21"E long.) and north outlet (12°57'22.86"N lat. and 77°44'40.56"E long.) in Varthur wetland during February 2009. Samples were stored in polythene bottles and were carried to laboratory for further analysis. Dissolved oxygen was analyzed on site using 125ml BOD bottles. Physical variables like pH, temperature (°C); total dissolved solids (mgL-1); salinity (mgL-1) and electric conductivity (µScm-1) were measured using EXTECH EC500 Probe immediately after collection. Other water chemistry variables like chloride, hardness, magnesium, calcium, sodium, potassium, nitrates and phosphates were analyzed in laboratory and analyses were carried out as per standard methods for the examination of water quality as mentioned20. Socio-economic survey A contingency valuation technique was applied for the economic survey of wetland through a participatory approach involving local school students. 235 people from 43 randomly selected households from Varthur and nearby villages were interrogated using a standard questionnaire by KK High School students (VIII to X grade), Bangalore. The questionnaire quantifies use values of the lake including demographic information, domestic water usage, irrigation, fishing and aquaculture, water usage for livestock, livestock fodder, groundwater recharge, health effects and family history. Valuation of resources through the survey aims to evaluate the economic status and dependency of residents. Demographic information included total number of persons/house, occupation and income per annum which relate to the dependency of residents on lake domestic water usage, irrigation, fishing and aquaculture, water usage for livestock and livestock fodder in turn the dependency of residents on lake water, aquatic plants and organisms. The use of groundwater resources highlights the indirect association with the Varthur lake, responsible for recharging local aquifers.
Citation: Ramachandra T. V., Alakananda B, Ali Rani and Khan M A, 2011, Ecological and socio-economic assessment of Varthur wetland, Bengaluru (India), J Environ Science & Engg, Vol 53. No 1. p 101-108, January 2011
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