解放闸灌域农田耗水时空变化特征及灌溉效率评价

Temporal and Spatial Variation of the Evapotranspiration and the Evaluation on Irrigation Efficiency in Jiefangzha Irrigation Region

根据内蒙古自治区河套灌区解放闸灌域多年遥感蒸散发数据(2000-2014年),分析了农田实际蒸散发年际变化、空间分布特征以及其与地下水埋深的相关性。结合水量平衡模型对灌域灌溉用水效率进行了评价,同时对大型灌区续建配套及节水改造以来灌域水循环要素年际变化进行了统计分析。结果表明:解放闸灌域农田蒸散发量年际变化呈增加趋势,多年平均蒸散发量为8.56亿m^3(597.30mm);2000、2003、2006、2009、2012和2014年农田蒸散在空间上表现为西部和东北部区域高于其他区域,其空间差异性并未随时间发生明显变化,与地下水埋深空间分布特征相似,蒸散发高值区域发生在地下水埋深较浅区域,潜水蒸发对农田蒸散发量影响不可忽视。节水改造实施以来,灌域净灌溉引水量有所减少,灌溉水利用系数得到提高,地下水位由1.76m降到2.16m,由此表明了节水改造对该地区生态环境改变的积极影响。

Interannual variability and spatial distribution of evapotranspiration which correlated with groundwater level were analyzed in Jiefangzha irrigation district based on remote sensing data from 2000 to 2014 .The irrigation use efficiency was evaluated based on water balance model ,and the interannual variability of the water cycle elements in the irrigation district was analyzed since the imple‐ment of water-saving irrigation projects .The results showed that the interannual variability of evapotranspiration （average 597 .30 mm） in irrigation district was increasing .For the spatial distribution in the irrigation district ,the evapotranspiration in the west and northeast was higher than the evapotranspiration in the others during 2000 ,2006 and 2012 .And the spatial distribution of evaptran‐spiration is similar to the groundwater depth that the shallow area occurred in western and northeastern .This phenomenon was at‐tributed to the evaporation of phreatic water which was higher in western and northeastern than other regions .Since the implement of water-saving irrigation projects ,net irrigation water diverted from Yellow River had been decreased .Meanwhile ,the irrigation ef‐ficiency of research region increased ,and the groundwater table dropped from 1 .76 m down to 2 .16 m which showed a positive per‐formance of water-saving project .