Three Springs at the Foot of the Hills

Three outlets push water up at Baotu in a tight line that rises and falls together, and the sound of it is the point: three jets issuing side by side gave the Qianlong Emperor the name Number One Spring under the Heaven, which he also cut in stone beside the pool on his journeys down the Grand Canal. It heads the seventy-two famous springs of Jinan, and it is the most renowned of the more than seventy named artesian springs downtown. The spring is not new. The Spring and Autumn Annals record a meeting of the rulers of Lu and Qi at Luo in 694 BC, and Li Daoyuan wrote of it that the spring source rises and the water wells up like a wheel. The Guanlan Pavilion stands on the west side of the pool, and a hall for the poet Li Qingzhao stands by the Shuyu Spring.

Baotu is a typical artesian well. Below Jinan an impermeable granite bed forms the floor, with permeable limestone deposits above it, and the ground slopes from south to north. Rain falling on the mountains south of the city sinks into an Ordovician karst aquifer whose recharge area lies there, and the water moves underground northward. Where the water reaches a fissure in the rock under pressure it rises on its own — the self-flowing well that Baotu is. The springs fed by this aquifer discharge about 300,000 to 350,000 cubic metres a day, and Baotu's own water holds a constant 18 degrees Celsius the whole year round. The city protects the flow by restricting groundwater pumping and by recharging the southern mountains, which is why the water is now treated as a public asset rather than as a resource to draw down.

A spring that runs on mountain rain is a spring that can stop. The first recorded drying of Baotu was on 30 March 1976, and from the 1970s the springs stopped several times because too much water was being pumped out of the aquifer for human use. The longest silence lasted 926 days, from 14 March 1999 to 17 September 2001. Then the water came back on 6 September 2003 and has run since. The city publishes the groundwater level for Baotu and Black Tiger every day and issues warnings when it falls below set thresholds, which turns a geological process into something you can follow in the newspaper. The record high in that watching came on 18 October 2021, when the level reached 30.18 metres, the highest since 1966. The pool is loud again; the measuring is the quieter, newer part of the story.