City workers Friday closed Barton Springs Pool in Zilker Park because cracks in a tunnel running underneath the pool had caused a leak, dropping the pool level about a foot before the leak was identified.

It took a team of engineers, hydrologists and biologists to locate the leak and come up with a way to fix it. There's an underground crack in the wall that surrounds the pool, and water is leaking from that crack and draining into a tunnel that help keeps the pool from flooding in heavy rain.

City officials say they will stop the leak by using large rocks to dam up the tunnel, but they say it is only a short-term fix. Engineers will be called in to assess the situation and determine a long-term solution.

The pool is about 30 years old, and officials say the cracks were caused by age. In fact, the tunnel has leaked in the past and the problem has been patched.

Austin City Council authorized $6.2 million for Barton Springs Pool, and money from that will be allocated to fixing the leak.

One of the concerns of water draining out of Barton Springs Pool is that it also affects the water level of the neighboring spring that is home to 800 rare salamanders.

"We're concerned about water levels dropping here to the point that it starts threatening the salamanders that inhabit this site," said David Johns, hydrogeologist.

Johns says he has blocked off the exit and is monitoring how quickly the water is dropping.

"The fate of the salamander has really helped enter the equations as to how were solving this problem and we're keeping it in mind as we deal with the larger issue," Johns said.

Johns and his team plan to monitor the situation over the weekend and are prepared to take steps to save the salamanders if need be.

A spokesman with Austin Parks & Recreation told KVUE News Friday evening that the work had been completed and that the pool would re-open Saturday morning.