Rear Tzuhu sits nestled among the mountains of the Hsichou range. In the days before it was a restricted area, the locals called it Dragon Pass Hollow. The pond has a large capacity and serves as a natural reservoir. It still boasts fish aplenty, and locals used to fish here and sell their catch on the streets of Tahsi to supplement their family incomes.
後慈湖則緊鄰溪洲山脈，群山環抱，早年尚未管制前，在地人稱為「龍過脈埤」，埤塘水量豐沛，有調節蓄水功能；湖中還有不少游魚，當地人常捕撈後運至大溪街上販售，貼補家計。