《水经注·卷三十八》
水南十里有井数百口，浅的四五尺，或三五丈，深的就测量不出了。
水南十里，有井数百口，浅者四五尺，或三五丈，深者亦不测其深。
There are hundreds of wells ten li south of the river, some as shallow as four or five feet or three or five meters, while the deeper ones are impossible to measure.