Assessing the performance of different cover materials, in mitigation of evaporation from free water surfaces in Sulaimani Governorate / Iraq

Tariq Hama Karim1,  Khalid Taiyb Muhammad 2& Roshn Mahmud Rasul2

1College of Agriculture ,University of Salahaddin                        

2College of Agricultural sciences ,Univerity of Sulaimani                             

In Iraqi Kurdistan region with intensive solar radiation and high vapor pressure deficit, particularly during the summer season, evaporative losses constitute a substantial amount of total stored water. To quantify and estimate evaporation losses besides testing the performance of some selected treatments for mitigating such losses a series of sequential experiments were implemented during some selected rainless months of 2015 and 2016 using evaporation pans. Each experiment was laid in completely randomized design. The treating materials encompassed indigenous and nonindigenous ones. Additionally, meteorological parameters were obtained for the test periods to relate pan evaporation to these parameters on one hand and to estimate pan coefficients from them, on the other hand. In this study the results were; 1) The small plastic balls as a covering materials (D =40 mm) offered the highest percent of evaporation reduction (60.81%) compared to those under large balls and under combination of these two sizes. 2) Comparison of three indigenous plant parts as shading cover, namely, Reed stems, Washingtonian fronds and Date palm mat, showed that the Date palm mat was the most effective material for reducing evaporation. 3) It was noticed that cardboard offered the highest performance compared with two other covering or shading materials (Cork disk and licorice branches) for reducing evaporation. 4) There was not a steady reduction in evaporation rate with an increase in monolayer application rate. The maximum reduction in evaporation rate occurred at an application rate of 0.226 g pan-1  Day-1 23.7%. 5) The order of preference of some screened treatment under the same atmospheric evaporation demand was:  Small balls > Date palm mat > Monolayer > Control. 6). It was also noticed that the monolayer offered a higher performance during the field tests compared to that obtained during the pan evaporation experiments.

  Key Words: Performace,Cover material, Mitigation, Evaporation, Water surface, Sulaimani


[1] Tabari, H. (2010). Evaluation of reference crop evapotranspiration equations in various climates,      Water resources management, 24(10), pp. 2311-2337.

[2] Gokbulak, F. and Ozhan, S. (2006). Water loss through evaporation from water surfaces of lakes and reservoirs in Turkey', Official Publication of the European Water Association, EWA.

[3] Panjabi, K., Rudra, R. and Goel, P. (2016). Evaporation Retardation by Monomolecular Layers: An Experimental Study at the Aji Reservoir (India)', Open Journal of Civil Engineering, 6(03), P. 346.

[4] Qadir  ,K.S. (2009). Evaluation Of Soil Pitting As A Technique For Soil And Water Conservation In Sulaimani  Governorate, A thesis Submitted to the Dept. of Soil and Water Science as partial   Fulfilment of the requirement of PhD degree.

[5] Hesse,P.R. (1972).  A Text book of Soil Chemical analysis. Chemical Publishing Co. INC. New York.

[6] Allen, R. G., Pereira, L. S., Raes, D. and Smith, M. (1998). Crop evapotranspiration-Guidelines for   computing crop water requirements-FAO Irrigation and drainage paper 56', FAO, Rome, 300(9), pp. D05109.

[7] Alam, S. and AlShaikh, A. A. (2013). Use of palm fronds as shaded cover for evaporation reduction to improve water storage efficiency', Journal of King Saud University-Engineering Sciences, 25(1), pp. 55-58.

[8] Gallego-Elvira, B., Martínez-Alvarez, V., Pittaway, P., Brink, G. and Martín-Gorriz, B. (2013).    Impact of micrometeorological conditions on the efficiency of artificial monolayers in reducing evaporation', Water resources management, 27(7), pp. 2251-2266.

[9] Tang, T., Pauken, M., Jeter, S. and Abdel-Khalik, S. (1993). On the use of monolayers to reduce evaporation from stationary water pools', Journal of heat transfer, 115(1), pp. 209-214.

[10] Kahalekar, Umesh J. and Kumawat ,Hastimal S. (2013). Evaporation suppression from water surfaces using chemical films. international journal of civil engineering and technology (IJCIET).Volume( 4) . 3, pp. 185-196.

[11] McJannet, D., Cook, F., Knight, J. and Burn, S. (2008). Evaporation reduction by monolayers: overview, modelling and effectiveness', Urban Water Security Research Alliance Technical Report, (6), pp. 10-16.

[12] Hobbs, E.H. (1961). Reduction of evaporation by monolayer films .  Proc. Hydrology Sympossium No.2, Evaporation, Pp. 233-40. Ottawa, Queen’s Printer.

[13] Erick, S. (2007). Controlling evaporation losses from large storage dams using chemical monolayers.  Report, Centre for Engineering in Agriculture: University of Southern Queensland, Australia

[14] Alvarez, V. M., Baille, A., Martínez, J. M. and González-Real, M. (2006). Efficiency of shading materials in reducing evaporation from free water surfaces', Agricultural Water Management, 84(3),  pp. 229-239.

[15] Saggaï, S., Saggaï, M. and Hancock, N. (2013). Pdf. Laboratory study of the effect of hexadecanol monolayer on the aquatic fauna (Case of Tilapia Nilotica)'.

[16] Fitzgerald, L.M. and Vines, R.G., 1963. Retardation of evaporation by monolayers: practical aspects  of the treatment of large water storages. Australian Journal of Applied Science, 14: 340-346.

[17] Frenkiel, J. H. and Frenkiel, J. (1965). Evaporation reduction: physical and chemical   principles and   review of experiments. UNESCO Paris.