Hamilton Pool is almost clean again

AUSTIN (KXAN) - Lee Malone is a commercial diver with years of experience in coastal waters. These days, though, he works in virtual darkness, surrounded by thickly silted water in one of central Texas' most beloved swimming holes.

Malone wears a heavy metal mask connected to a machine that delivers fresh air as he manhandles a cumbersome six-inch hose. On the other end of the hose is more machinery, essentially gigantic vacuum cleaners that suck the silt, along with leaves and sticks, from the water and into massive tanks equipped with state-of-the-art filters.

All this was made necessary by a construction project that went badly wrong back in April of 2007.

Coldwater Development, Ltd., the developer, was preparing land for a big neighborhood of luxury homes. The excavation contractor, Rodman LLC, was doing the site work for a road designed to run through the neighborhood. According to the results of an investigation by Travis County , systems erected to hold back storm water runoff from the site were inadequate. When heavy rains saturated the area, those systems failed, allowing tons of dirt and debris to wash first into Hamilton Creek, and then downstream into Hamilton Pool .

The pool was severely damaged.

"It hurt the ability of the water to hold its dissolved oxygen, its suspended solids; the ability of the water to be clear enough for us to see to the bottom and the resulting aesthetic value, as well," said Victoria Harkins, the consulting engineer hired to supervise the cleanup.

There was no health threat, but to put it simply, the place was a mess. It was like climbing into a bathtub full of already filthy water.

"And then, when people get in the water, it doesn't take very long for the silt to essentially remix," Harkins said. "It's like milk and it doesn't settle any time soon. So it's essentially making the bathtub dirtier every time you get in."

The original site of the pollution event lies along the Travis/ Hays County line and both counties filed suit against the two companies. Because the anti-runoff systems did not hold up, state officials decided the companies had violated the Texas Water Code and the state Commission on Environmental Quality also sued, as did landowners along the creek, downstream from the development.

Eventually, the lawsuit was settled for $3.5 million and using that money, cleanup crews went to work. It was not an easy job. First of all, it made no sense to clean the swimming hole without cleaning the six miles of creek between the pool and the construction site. Since the creek was also clogged with silt, the next heavy rain would just send much of it downhill and into the newly cleaned creek. So crews had to man fire hoses, brooms, hoes and shovels in a tedious, back breaking, months-long effort to scrub the creek bed clean.

Meanwhile, the source of the pollution was shored up and planted in native grasses to prevent further contamination. The creek project worked so well that even heavy runoff from Tropical Storm Hermine ran clear and clean on its way downstream to Hamilton Pool.

Once the creek work was done, divers were called in for that vacuum job in the pool.

"Whenever we get done, basically, you'll be able to see almost like straight down like 20 feet," said Malone after climbing out of the water and onto a pontoon boat. "It'll be really nice and clear."

Also on that pontoon is a large pump that pulls the dirty water from the pool and sends up a high cliff and then another 2,000 feet uphill to a series of enormous tanks and filters that remove the junk and send the newly cleaned water back into Hamilton Pool.

"As we clean, you can see it," Harkins said. "Every day when we finish, we give the pool a time to rest, and in the morning it's remarkable the difference from even just one day of good solid processing for eight hours during the day."

The job is expected to last through mid to late April, finishing up just in time for the summer outdoor season. Visitors, Harkins promises, will be delighted.

"You'll be able to see the underwater rocks, see the edge of the rocks," she said. "There's a beautiful, kind of geographic pattern of rocks that have fallen from the cave above and you will be able to see that again."

So what happens to all the debris and silt? It is being collected and dumped in an abandoned quarry nearby.

The quarry was dug to provide fill for the construction of Ranch Road 3238 which winds through the area. In fact, that road actually winds much too close to the quarry. State law requires that quarries must be no closer than 150 feet from such a road, if school busses drive on it. In this case, the road and the quarry are closer than that. But by the time all the fill is packed into the hole, there will no longer be any danger of a bus missing a curve and diving headlong into a giant hole in the ground.

"We will stabilize the fill," said Harkins, "and then put some top soil on it and vegetate it with some native seed. It will look better than the