Rain falling on the roof is directed into a 7,500-litre above-ground storage tank so it can be used for irrigation.
屋顶的雨水下落直接流到7,500升的地面储藏池中，它可以用来灌溉。
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The optimum design can be selected through comparing sunken tank - above - ground pump, sunken tank - submerged pump and land tank - above - ground pump.