J. Mt. Sci. (2012) 9: 256–261 DOI: 10.1007/s11629-012-2186-z 256 Abstract: The primary purpose of this study was to assess water losses by evapotranspiration, evaporation and seepage in arid zone. Normally, evaporation and seepage are the main causes of water losses. For modeling water losses, a combination of Genetic Programming (GP), Penman-Monteith (PM) and Penman combination model for measurement of evapotranspiration, evaporation and seepage has been developed. The results were found to be varying depending on how the evaporation and seepage phenomena are modeled. These results show that that there is an improvement in reducing evapotranspiration, evaporation and seepage losses in arid and semi-arid region. Keywords: Arid zone; Evaporation; Evapotranspiration; Seepage; Water losses; China Introduction Water losses is a big problem throughout the world. Irrigation and industries are the main consumers of water. In the arid and semi-arid regions of the world, attention is being focused on the search for new methods to conserve existing water supplies. Studies have revealed that evaporation ponds for the disposal of saline drainage water are used most extensively in the Aral Sea Basin; most ponds are large and located outside irrigation perimeters (Shiau and Lee 2005; FAO 1997). Water stored on the surface, in lakes or reservoirs is subject to loss by seepage and evaporation. Evaporation is an essential part of the water cycle and it is the process by which liquid water moves from soil, lake or river in form of vapor to the atmosphere. It has been shown that evaporation from the oceans accounts for more than 75% of the water delivered as precipitation, with the balance occurring on land, inland waters and plant surfaces (Armienta and Rodriguez 1995). (Armienta and Rodriguez 1995; Shiff 1961). Various studies have discussed the problem of evaporation with suggestions that the rate of evaporation depends on the temperature difference between the evaporating surface and the air (Armienta and Rodriguez 1995), the relative humidity, and wind (Armienta and Rodriguez 1995; Shiff 1961). It also revealed that the amount of water lost to evaporation from storages depends on many factors including atmospheric evaporative demand Water Losses in Arid and Semi-Arid Zone: Evaporation, Evapotranspiration and Seepage MUPENZI Jean de la Paix 1, 2, 3, 4 *, LI Lanhai 1 , GE Jiwen 2 , NGAMIJE Jean 3 , ACHAL Verenyam 1 , HABIYAREMYE Gabriel 3 ; HABUMUGISHA Jean de Dieu 4 1 State Key laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 Beijing road south, Urumqi, Xinjiang, 830011, China 2 China University of Geosciences (Wuhan), 388 Lumo Road, Wuhan 430074, Hubei, China 3 Independent Institute of Lay Adventists of Kigali (INILAK) P O Box 6392, Kigali-Rwanda 4 Institut Polytechnique de Byumba (IPB), PO Box 25 Byumba, Rwanda *Corresponding author, e-mail: jeandelapaixmup@yahoo.fr © Science Press and Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2012 Received: 20 May 2011 Accepted: 8 December 2011