Estimation of Evaporation Loss in Red hills Lake at Thiruvallur District, Tamil Nadu
Redhills lake, Chennai City’s primary reservoir serves as the primary storage nearly about 40 years old. It receives water from Poondi and Cholavaram reservoir and is the last stop before water transmitted to Kalpak Water Works of Metro water. Generally water storage reservoirs are prone to losses through seepage and evaporation. Seepage generally occurs when the water escapes through the bottom of the reservoir and horizontal filtration through weirs and dykes. Owing to the heat energy of sun, water loss take place by evaporation from the surfaces of lakes, ponds, canals, rivers, reservoirs, etc. Water loss by evaporation is a very serious problem in semiarid and arid regions. Red Hills Lake is of no exception. In this thesis, the evaporation losses in Red hills lake is estimated by Bulk Aerodynamic method and Combined Penman Monteith Model using real time meteorological data for the past 10 years (2004 -2013) and compared between them. The relationship between water losses due to evaporation, water level in the lake, lake inflow and lake water storage were carried out. The evaporation values determined by Bulk Aerodynamic Method Which is the function of vapour pressure difference between the water surface and atmosphere, as well as horizontal wind speed varies between 0.20 mm and 39.98 mm with an average of 7.56mm. The evaporation values determined by Combined Penman Model which depends on solar radiation varies between 1.82 mm and 30.54 mm with an average of 9.56 mm..On comparison, Combined Penman Monteith Method showed the better evaporation values and it forms the favouarble method as it depends on minimum factors of solar radiation and sunshine hours for finding evaporation loss in the study area.
2) Elementary Engineering Hydrology, M.J.Deodahar, Emeritus Fellow, AICTE, NewDelhi, India.
3) Long-Term Estimation of Water Losses Through Evaporation from Water Surfaces of Nasser Lake Reservoir, Egypt,Ali M. Hamdan and Mohamed Zaki,IJCEE-IJENS Vol: 16 No: 05.2016.
4) A Comparison of several methods of estimating the evaporation of Lake Flevo, J.Q .Keijman and R.W.R Koopmans, Volume 24,Issue 7,1999,pages 851-859.
5) Herbeck,G.E (1962),A Practical field technique for measuring reservoir evaporation utilizing mass-transfer theory,Prof.paper UG Geol. Survey 272-E.
6) Brutsaert, W.(2005),Hydrology: An Introduction ,605 pp.,Cambridge Univ. Press, New York.
7) Hounam, C.E (19273), Comparison between Pan and Lake evaporation, World Meteorological Organization, Technical Note,no,126,52 p.