Some of the ideas that Austin Water Utility officials are considering, which they presented to a city committee Monday night, are likely to draw criticism from the public.
The ideas include lowering the level of Lake Austin and then pulling rainwater from it, an option previously floated by the Lower Colorado River Authority that made recreational users and homeowners along the lake unhappy.
Another controversial idea: putting reclaimed water, or treated effluent, into Lady Bird Lake. The city would allow some time for the effluent to mix in, then pump some water from Lady Bird Lake directly into a city plant located farther upstream, on Lake Austin, where water is treated and turned into drinking water.
Another potentially expensive idea would be pulling groundwater from aquifers east and northeast of Austin. Several organizations and businesses have already approached the city looking to do just that.
A City Council-appointed committee has until late June to recommend water supply options to the council, which will make the final decision.
Austin has a long-term deal with the LCRA to get water from lakes Travis and Buchanan well into the future. (Austin treats the water at two plants farther downstream, on Lake Austin.)
The city has cut its water use significantly in recent years through conservation. But as those two lakes’ levels continue to dwindle — they are now only about 35 percent full — and Central Texas’ population booms, Austin needs to start thinking about getting some water elsewhere, city leaders say.
“We think this is the worst drought at least since the lakes were built in the 1940s. This summer, it’s possible the lakes could reach the lowest point they’ve been,” said Austin Water Utility Assistant Director Daryl Slusher. “We feel like we have a responsibility to come forward with options for augmenting the water supply.”
The big considerations are how soon each option could provide Austin with more water, how difficult each would be to carry out and how much each would cost.
For example, one of the costliest options would be aquifer storage — or storing reclaimed or treated water underground for use later — which city officials say would cost $130 million to do.
It’s too early to say how much any of the options would raise Austinites’ water bills.
One idea that would be relatively cheap and quick would be lowering Lake Austin, officials said.
That dammed lake is normally kept at a constant level, but if it were lowered three or four feet and then allowed to fill up during rainstorms, the city could capture the extra water for use.
The city wouldn’t have to build anything new to do it — hence, no cost — but it wouldn’t yield much water: only about 5,000 acre-feet, a fraction of the 240,000 acre-feet Austin uses each year. An acre-foot is roughly equal to the amount of water used by three average households in a year.
The city also would need the LCRA’s blessing to do it, and residents and recreational users balked at the idea last year.
People with docks along Lake Austin could see water levels regularly rise and fall, and the lake’s recreational uses could become secondary to its use as a reservoir.
Putting reclaimed water into Lady Bird Lake, then later piping water from that lake into the Ullrich Water Treatment plant on Lake Austin would yield more water — about 20,000 acre-feet a year. (There is a state ban on putting treated effluent into Lake Austin.)
But it would cost about $30 million and two or three years to build the pipes needed to get the reclaimed water to Lady Bird Lake.
Groundwater has its own challenges.
Several groups have approached Austin Water Utility about teaming up to pull groundwater from the Carrizo-Wilcox Aquifer to the east or the Northern Edwards Aquifer, which runs through northern Travis and Williamson counties and into Bell County.
But Austin might find itself in political fights with groundwater districts that are reluctant to see their water pumped and exported. Groundwater also might require condemning land and building pipes to transport water long distances, making it a potentially expensive fix.
Groundwater would also need to be made compatible, through the treatment process, with the mineral content of the Colorado River water it would be mixed with.
©2014 Austin American-Statesman, Texas
