Water Act Article 21
If the authority-in-charge determines, based on hydrological testing, that a certain water source under its jurisdiction will have a surplus within a certain period after meeting the water usage needs of all purposes, it may authorize temporary right of use to others for the same period. If the water supply runs short all of a sudden, the authority-in-charge may suspend such temporary rights.
中文原文 水利法第21條
主管機關根據水文測驗，認為該管區域內某水源之水量，在一定時期內，除供給各水權人之水權標的需要外，尚有剩餘時，得准其他人民在此定期內，取得臨時使用權，如水源水量忽感不足，臨時使用權得予停止。