Water balance variability across Sri Lanka for assessing agricultural and environmental water use
Water balance variability across Sri Lanka for assessing agricultural and environmental water use
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DOI：
10.1016/s0378-3774(02)00128-2
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发表时间：
2003-02
影响因子：
6.7
通讯作者：
W. Bastiaanssen;L. Chandrapala
中科院分区：
文献类型：
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作者：
W. Bastiaanssen;L. Chandrapala
本文介绍了一种利用公共领域卫星数据进行农业和环境用水水文数据收集和评估的新程序。利用观测到的降雨量和遥感到的1公里网格分辨率的实际蒸发率估算了斯里兰卡年水平衡的变率。采用地表能量平衡算法（SEBAL），以10 d为单位对根区蒸发量和库存量的实际变化进行了评估。水平衡由径流分量和剩余项关闭。蒸发量和径流量的估计分别用闪烁测量法和仪表读数与地面测量结果进行了验证。给出了斯里兰卡103个河流流域的年水平衡情况。剩余项似乎小于降雨量的10%，这意味着对政策和决策的水平衡有充分的了解。作为水会计程序的输入，获取水平衡数据是必要的，水会计程序只是描述水文系统中的水状况（例如，全国范围、河流流域、灌溉计划）。结果表明，灌溉部门用水量不超过净流入水量的7%。农业用水和环境系统用水分别占净流入水量的15%和51%。雨养农业和灌溉农业的消费用途大致相等。农业和混合植被的蒸发率相似，因此，低生产力的牧场可以转变为雨养农业，而不会对下游用户的水供应产生不利影响。流入印度洋的未使用水量占净流入水量的34%，因此斯里兰卡有进一步开发水资源的空间。
This paper describes a new procedure for hydrological data collection and assessment of agricultural and environmental water use using public domain satellite data. The variability of the annual water balance for Sri Lanka is estimated using observed rainfall and remotely sensed actual evaporation rates at a 1km grid resolution. The Surface Energy Balance Algorithm for Land (SEBAL) has been used to assess the actual evaporation and storage changes in the root zone on a 10-day basis. The water balance was closed with a runoff component and a remainder term. Evaporation and runoff estimates were verified against ground measurements using scintillometry and gauge readings respectively. The annual water balance for each of the 103 river basins of Sri Lanka is presented. The remainder term appeared to be less than 10% of the rainfall, which implies that the water balance is sufficiently understood for policy and decision making. Access to water balance data is necessary as input into water accounting procedures, which simply describe the water status in hydrological systems (e.g. nation wide, river basin, irrigation scheme). The results show that the irrigation sector uses not more than 7% of the net water inflow. The total agricultural water use and the environmental systems usage is 15 and 51%, respectively of the net water inflow. The consumptive use of rain-fed and irrigated agriculture are approximately equal. The evaporation rates in agriculture and mixed vegetation are similar, so that low productivity rangelands can be transformed into rain-fed agriculture without detrimental effects on water availability to downstream users. The unused water flow to the Indian Ocean is 34% of the net inflow, hence there is scope for further water developments in Sri Lanka.