Water Balance Study and Irrigation Strategies for Sustainable Management of a Tropical Ethiopian Lake: A Case Study of Lake Alemaya

被引:0
作者
Shimelis Gebriye Setegn
V. M. Chowdary
B. C. Mal
Fikadu Yohannes
Yasuyuki Kono
机构
[1] Florida International University (FIU),Department of Earth and Environment
[2] RRSC,Department of Agricultural and Food Engineering
[3] IIT campus,Department of Agricultural Engineering
[4] IIT,Center for South East Asian Studies
[5] Alemaya University,undefined
[6] Kyoto University,undefined
来源
Water Resources Management | 2011年 / 25卷
关键词
Lake water balance; Irrigation performance; Scheduling; Chat; Lake Alemaya; Ethiopia;
D O I
暂无
中图分类号
学科分类号
摘要
Lake Alemaya in the Ethiopian Highlands has historically provided the surrounding area with water for domestic use, irrigation, and livestock and has served as a local fishery tank. Increasing irrigation and domestic water use, change in the local climate and changes in the surrounding land cover are believed to be the causes of Lake Alemaya’s demise. Expansion of major irrigated crops in particular chat (Catha Edulis), potato and vegetables and non-judicious use of irrigation water in the Lake Alemaya watershed led to presumption that irrigation is partly responsible for the withdrawal of large quantity of water from the lake. Thus, water balance study of Lake Alemaya was carried out under presumed scenarios in order to study the possible trends and fluctuations of the lake water level in response to proposed scenarios. Further, it is essential to study the irrigation performance for developing optimal irrigation schedules in the study area to make the best use of available water for long term sustainability of the water resources of Lake Alemaya. It was identified that expansion of the irrigated area in general and chat cultivation in particular in the study area have been the key to sustainable management of lake water, hence its expansion during the past 37 years (1965–2002) was studied through interpretation of satellite data. Subsequently, performance evaluation of the small-scale irrigation practices for major irrigated crops was carried out. Optimal irrigation schedules for different crop seasons were also developed for these irrigated crops using CROPWAT software. It was found that chat area increased from 190 ha in 1996 to nearly 330 ha in 2002. Further, it was observed that 43% surface area of the lake has reduced within a span of 37 years. Overall, maximum irrigation intensity of chat, potato and vegetables is observed during the first irrigation season of the crop calendar. Particularly, in case of chat, irrigation performance indicators such as Relative Water Supply (RWS), Relative Irrigation Supply (RIS), Depleted Fraction (DF) and Overall Consumed Ratio (OCR) values indicated poor performance of irrigation practices. From the analysis, it was found that the application of a fixed irrigation depth and fixed irrigation interval combinations of (25 mm—25 day), (20 mm—20 day), or (20 mm—25 day) are recommended for chat in the study area. Optimal irrigation schedules were decided on the basis of combination of irrigation interval and depth that results in low loss of irrigation water with reasonable yield reduction. Thus, determination of appropriate water management strategy can ensure proper utilization of the available water resources and improve the water application efficiency of the small-scale irrigation practices around Lake Alemaya, Ethiopia.
引用
收藏
页码:2081 / 2107
页数:26
相关论文
共 103 条
  • [1] Aldaya MM(2010)Incorporating the water footprint and virtual water into policy: reflections from the Mancha Occidental Region, Spain Water Resour Manage 24 941-958
  • [2] Martinez-Santos P(2007)Impact of water overexploitation on highland lakes of eastern Ethiopia Environ Geol 52 147-154
  • [3] Llamas MR(1997)Paleoevaporation and paleoprecipitation in the Tanganyika Basin at 18000 years B.P. inferred from hydrologic and vegetation proxies Quat Res 47 295-305
  • [4] Alemayelu T(2004)Using depleted fraction to manage the groundwater table in irrigated areas Irrig Drain Syst 18 201-209
  • [5] Furi W(1988)Scheduling irrigation for corn and soybeans in the southern coastal plains Trans ASAE 31 513-518
  • [6] Legesse D(2003)GIS based decision support system for groundwater assessment in large irrigation projects Agric Water Manag 62 229-252
  • [7] Bergonzini L(2005)Decision support framework for assessment of non-point source pollution of groundwater in large irrigation projects Agric Water Manag 75 194-225
  • [8] Chalie F(2008)Assessment of surface and subsurface waterlogged areas in irrigation command areas of Bihar state using remote sensing and GIS Agric Water Manag 95 754-766
  • [9] Gasse F(2001)Lake evaporation estimates in tropical Africa (Lake Zimay, Ethiopia) J Hydrol 245 1-18
  • [10] Bos MG(2003)An investigation of the physical and socioeconomic determinants of soil erosion in the Hararghe highlands, Eastern Ethiopia Land Degrad Dev 14 69-81