内陆干旱区降水稀少,蒸发强烈,为了减少内陆干旱区平原水库的无效蒸发,提高水库的利用率,缓解水资源紧张,进行了塑料空心板覆盖水库水面的试验。通过隔断水面与外界环境的接触,从而抑制水面蒸发。塑料空心板的湿润面积由3部分组成风浪打湿的面积、板与板之间碰撞挤出的水形成的湿润面积、板与坝坡碰撞挤出的水形成的湿润面积。应用统计学原理,依据现场试验的实测数据,计算在不同气象条件下浮板的湿润面积,统计一个完整的非冰冻期资料;得出不同风速出现的概率及防蒸发系数,计算防蒸发量;对比分析不同面积下防蒸发浮板覆盖水库水面的节水效率。结果表明现场3个方案试验的节水效率分别为55.38%,65.97%,80.10%,浮板面积越大节水效率越高,板的节水效果和试验布置方式有关,将浮板布置在围栏之内,最大可提高节水效率1.45%;将浮板做成整体时节水效率提高较为明显,最大可提高17.68%。

In the aim of reducing ineffective evaporation from reservoir waters in inland arid plain area, we conducted tests on plastic hollow plate covering the reservoir water surface. By preventing the water surface from external environment, the plates could suppress water surface evaporation, hence alleviating water shortage and improving the utilization rate of reservoirs. The wet area of plastic hollow plate consists of three parts: area wetted by wind waves, area wetted by the collision between plates, and area wetted by the collision between plates and dam slope. According to observed data we calculated the wet area in different meteorological conditions. And through statistical analysis on the probability of wind speed and corresponding evaporation reduction coefficient in a complete non-frozen period, we calculated the evaporation reduction amount and compared the water-saving efficiency in the presence of different cover area. According to results we obtained three different values of water saving efficiency: 55.38%, 65.97%, and 80.10% in three different test conditions. The results suggest when the plate area gets larger, the water-saving efficiency is higher. Moreover, the water-saving effect is related with test arrangement: when the plates are enclosed in a fence to avoid collision, the water-saving efficiency improves by 1.45% to the maximum; and when the plates are made integrate, the water-saving efficiency can be increased by 17.68%.