Remote sensing and hydrological measurement based irrigation performance assessments in the upper Amu Darya Delta, Central Asia

Abstract In the Aral Sea Basin, where the Central Asian countries compete for limited water resources, reliable information on the actual water use for eight million ha of irrigated land are rare. In this study, spatially distributed land use data, seasonal actual evapotranspiration, and reference evapotranspiration derived from multitemporal MODIS data were combined with in situ water flow measurements for irrigation performance assessments in the upper Amu Darya Delta. The functioning of the major irrigation and drainage which supplies an agricultural area of 270,000 ha in the Uzbek province Khorezm was analysed using water balancing and adequacy indicators of irrigation water use. An average relative evapotranspiration of 95% indicated fulfilled water demands and partly over-irrigation, whereas values below 75% disclosed inadequate water supply in distant parts of the irrigation system. On the other hand, immense water withdrawals of approximately 24,000 m 3  ha −1 recorded at the system boundaries between April and September 2005 clearly exceeded the field water demands for cotton cultivation. Only 46% of the total irrigation amounts were consumed for crop production at field level. Throughout the vegetation period, approximately 58% of the total available water left the region as drainage water. Monthly observations of the depleted fraction and the drainage ratio highlighted drainage problems and rising groundwater levels at regional scale. In the most distant downstream subsystem, a high risk of groundwater and soil salinity during the main irrigation phase was found. A combination of high conveyance losses, hydraulic problems, direct linkages between irrigation and drainage, and low field application efficiencies were identified as major reasons for underperforming irrigation. The findings underlined the necessity of water saving and of reconsidering water distribution in Khorezm. The remote sensing approach was concluded as a reliable data basis for regular performance assessments for all irrigation systems in Central Asia.

[1]  Wim G.M. Bastiaanssen,et al.  Relating Crop Water Consumption to Irrigation Water Supply by Remote Sensing , 1997 .

[2]  David Molden,et al.  Accounting for water use and productivity , 1997 .

[3]  Russell G. Congalton,et al.  A review of assessing the accuracy of classifications of remotely sensed data , 1991 .

[4]  Yann Chemin,et al.  Using remote sensing data for water depletion assessment at administrative and irrigation-system levels: case study of the Ferghana Province of Uzbekistan , 2004 .

[5]  William P. Kustas,et al.  Daytime net radiation estimated for a semiarid rangeland basin from remotely sensed data , 1994 .

[6]  K.M.P.S. Bandara,et al.  Assessing irrigation performance by using remote sensing , 2006 .

[7]  S. Mohan,et al.  Irrigation crop coefficients for lowland rice , 1994 .

[8]  D. Raes,et al.  Deficit irrigation as an on-farm strategy to maximize crop water productivity in dry areas , 2009 .

[9]  Ramaswamy Sakthivadivel,et al.  Satellite remote sensing for assessment of irrigation system performance: a case study in India , 1997 .

[10]  A. Martínez-cob,et al.  Evaluation of satellite evapotranspiration estimates using ground-meteorological data available for the Flumen District into the Ebro Valley of N.E. Spain , 2009 .

[11]  Trevor W. Tanton,et al.  Remote sensing and GIS for estimation of irrigation crop water demand , 2005 .

[12]  Wim G.M. Bastiaanssen,et al.  Remote sensing and hydrologic models for performance assessment in Sirsa Irrigation Circle, India , 1999 .

[13]  Alan H. Strahler,et al.  The Moderate Resolution Imaging Spectroradiometer (MODIS): land remote sensing for global change research , 1998, IEEE Trans. Geosci. Remote. Sens..

[14]  Thomas Alexandridis,et al.  Water performance indicators using satellite imagery for the Fordwah Eastern Sadiqia (South) Irrigation and Drainage Project , 1999 .

[15]  R. Allen,et al.  Satellite-based ET mapping to assess variation in ET with timing of crop development , 2007 .

[16]  Erlangung der Doktorwürde.  Cotton, Rice & Water The Transformation of Agrarian Relations, Irrigation Technology and Water Distribution in Khorezm, Uzbekistan , 2008 .

[17]  B. Bouman,et al.  Scale effects on water use and water productivity in a rice-based irrigation system (UPRIIS) in the Philippines , 2007 .

[18]  S. S. Ray,et al.  Performance evaluation of an irrigation command area using remote sensing: a case study of Mahi command, Gujarat, India , 2002 .

[19]  C. Conrad,et al.  Remote Sensing and Hydrological Measurements for Irrigation Performance Assessments in a Water User Association in the Lower Amu Darya River Basin , 2011 .

[20]  Robin Pfister,et al.  Earth Observing System Data Gateway , 2001 .

[21]  A. Holtslag,et al.  A remote sensing surface energy balance algorithm for land (SEBAL)-1. Formulation , 1998 .

[22]  Wim G.M. Bastiaanssen,et al.  Irrigation Performance Indicators Based on Remotely Sensed Data: a Review of Literature , 1999 .

[23]  Informal network utilisation and water distribution in two districts in the Khorezm Province, Uzbekistan , 2004 .

[24]  Luis S. Pereira,et al.  Irrigation scheduling strategies for cotton to cope with water scarcity in the Fergana Valley, Central Asia , 2009 .

[25]  L. S. Pereira,et al.  Crop evapotranspiration : guidelines for computing crop water requirements , 1998 .

[26]  Erhan Akkuzu,et al.  Using satellite remote sensing to assess irrigation performance in Water User Associations in the Lower Gediz Basin, Turkey , 2009 .

[27]  C. Justice,et al.  Atmospheric correction of visible to middle-infrared EOS-MODIS data over land surfaces: Background, operational algorithm and validation , 1997 .

[28]  Christopher Conrad,et al.  Mapping and assessing water use in a Central Asian irrigation system by utilizing MODIS remote sensing products , 2007 .

[29]  C. Martius,et al.  Evaluation of young and adult tree plantations for biodrainage management in the lower Amudarya River Region, Uzbekistan , 2005 .

[30]  Irina Forkutsa,et al.  Groundwater table and salinity: Spatial and temporal distribution and influence on soil salinization in Khorezm region (Uzbekistan, Aral Sea Basin) , 2007 .

[31]  I. A. Walter,et al.  The ASCE standardized reference evapotranspiration equation , 2005 .

[32]  M. G. Bos.  Using the depleted fraction to manage the groundwater table in irrigated areas , 2004 .

[33]  Zhao-Liang Li,et al.  A physics-based algorithm for retrieving land-surface emissivity and temperature from EOS/MODIS data , 1997, IEEE Trans. Geosci. Remote. Sens..

[34]  Wim G.M. Bastiaanssen,et al.  Water balance variability across Sri Lanka for assessing agricultural and environmental water use , 2003 .