What has that drilling rig been doing over on Oasis Bluff? It is part of The City of Austin’s water treatment plant number four project.
http://www.ci.austin.tx.us/water/wtpfour.htm

From that site:
The WTP 4 project began back in the 1970s with the original site being selected and purchased in the mid 1980s. The plant will consist of water treatment facilities, a raw water intake and tunnel, pump stations, and pipelines to get water from Lake Travis through the plant and into the water system.
The Austin City Council has directed the Austin Water Utility to move forward on the design, engineering, and construction of a new 300 Million Gallons per Day (MGD) water treatment plant on the original site near Lake Travis to provide customers with potable water.
I was contacted by one of the companies involved.
Rhonda Price wrote:
Our firm is trying to set up presentations to interested organizations
regarding Water Treatment Plant #4. What would be the best mailing address
to send correspondence to? I have email addresses from your site which
will be very helpful, but would like to send information such as the
project newsletter via regular mail, too. Thanks!
Website: www.groupsolutionsrjw.com
–
Rhonda Price, APR
Senior Consultant
Group Solutions RJW
314 E. Highland Mall Blvd., Ste. 305
Austin, Texas 78752
Phone: (512) 448-4459
Fax: (512) 454-1342
http://www.groupsolutionsrjw.com
She sent along these two newsletters. (also available at the CoA site)
November 6, 2007 Newsletter
January 26,2006 Newslettter
Looks like we will get to watch them set the pipe for the project over the next year!