Estimation of Chitgar Lake Evaporation and the Impact of Chemical Coverings on its Reduction

Nejatian, Amir | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53564 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Tajrishy, Masoud; Irajizad, Azam
  7. Abstract:
  8. Reducing water evaporation is one of the ways to overcome the low precipitation and drought conditions in water reservoirs. For this purpose, extensive studies have been investigated on physical and chemical coatings on lakes and reservoirs. Physical methods often involve the use of floating covers on the water surface to block evaporation by shading, most of which are only suitable for reservoirs with surface areas smaller than 5 hectares. In chemical methods, the evaporation can be decreased by nanomaterial coating, usually, containing long-chain molecules, which by spraying them on the surface, molecular monolayers are formed. In this study, the effect of nanometer coatings on the surface evaporation of Chitgar Lake in Tehran was investigated. This lake has a considerable surface area of 130 hectares and annual evaporation of about a meter. Two pairs of American Class A evaporation pans have been used to estimate the evaporation of The Lake. One pair fixed on land and the other pair floated on the lake but connected to the shore. Evaporation was estimated using energy balance, mass transfer, combined and experimental methods, which form a total of 25 different relationships. Using statistical features and comparing them with each other, revealed that the mass transfer equation of Lake Okangan is the best relationship to estimate the lake's evaporation. Additionally, different nanocoatings consisting of Stearyl alcohol, Cetyl alcohol, Stearic acid, Calcium hydroxide, jojoba oil, and Aquatin were tested in both fixed and floating pans. It was found that 100% Aquatin coating had the best performance of 60% reduction in evaporation during the four day period and in terms of finances, with the price of 6000 Tomans (0.4 USD) per litre water, this coating can be beneficial
  9. Keywords:
  10. Evaporation Reduction ; Chitgar Artificial Lake ; Coating ; Cetyl Alcohol ; Evaporation Pan ; Stearyl Alcohol

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