Twin Falls, Idaho (KMVT-TV) The City of Twin Falls is busy working underwater.

Divers are busy filling cracks in Upper Blue Lake.

The main concern is managing the water level and stabilizing the lake.

The project is costing the city less than $20,000.

"This year we are back in the water we found a new crack last year that had a lot of water leaking underground and shows back up at alphas creek but we are going to plug that section off” Mike Trabert, Environmental Engineer City of Twin Falls.

"Were starting with sandbags to fill the main part of the crack then we are going back over with an inch and half of rock” said Paul Melni, Master Scuba Diver.

The divers do have risk while working 34-feet underwater.

"We dotted our "I" and crossed our "T" we have rescue diver out their watching what we are doing so we make sure to stay safe when we are down there."

The city says this is a very important project especially for the Country Club.

It’s about maintaining the lake level and keeping the appearance up for the residents.