Council wants to hear more on Lake Austin bulkhead restrictions

After hearing a presentation by the Watershed Protection Department yesterday, Council voted unanimously to delay making a decision on new restrictions on bulkheads, docks, and shoreline access on Lake Austin. Watershed staff believe those restrictions could help protect the lake from further shoreline erosion and other detrimental environmental impacts. Others believe the restrictions wouldn’t do enough to solve those problems and don’t reflect the concerns of Lake Austin residents.

 

Andrew Clamann, an environmental scientist with the Watershed Protection Department, said that the proposed amendments mainly concern bulkheads and trams.

 

Currently, trams are not referred to in the city code, despite the fact that they can accelerate erosion of the slope leading from the shoreline to homes and also damage the natural and traditional character of that slope.

 

As for vertical bulkheads — barriers erected by homeowners to repel waves –current code prohibits smooth vertical face bulkheads in the main body of the lake. The problem with enforcement, Clamann said, has been that the definitions of “smooth” and “vertical” are “open to interpretation.”

 

The problem with vertical bulkheads, Clamann said, is that wave reflection on vertical surfaces redirects energy outward and downward, thereby increasing lakebed erosion, eliminating wetland plants, increasing turbidity, and removing shallow water habitat for wildlife. Angled bulkheads would cut down on such problems significantly.

 

According to a 2009 survey, 50 percent of the properties on Lake Austin have vertical bulkheads.

 

The proposed code changes the Watershed Protection Department presented to Council would prohibit new boat ramps, vertical bulkheads (new bulkheads would not be permitted to exceed 45 degrees for any portion greater than one foot), and capturing or recapturing (filling in) land lost to erosion. Also, trams would have to be screened and tram owners would be required to provide vegetation underneath to prevent erosion and tree canopy.

 

“We need to clarify the prohibition of vertical surfaces, promote natural materials instead of smooth surfaces, and incorporate vegetation for the sake of water quality,” Clamann said.

 

John McIntyre, an engineer who has been designing shoreline structures for 25 years, took issue with staff’s conclusions, saying that there should be more than one solution to the problem of shoreline erosion. Echoing the sentiments of many area residents who spoke out against the proposed amendments, McIntyre said that it’s the boats on the lake that are causing the real problem.

 

“The biggest problem is the number of boats and the size of the waves they’re putting out,” McIntyre said. “Reflective waves aren’t really a problem. The waves that go unimpeded are the problem.” Pointing out that Lake Austin has a varied shoreline, from shallow shores to very rocky ones, McIntyre said, “There are different solutions that will fit those different criteria better.”

 

Mayor Lee Leffingwell said that the problem of shoreline erosion appeared to be bigger than just vertical bulkheads. Besides, he said, pre-existing vertical bulkheads would be exempt from the regulations anyway. Therefore, it would be in the best interest of the city to address the issue of the waves themselves.

 

“If we have a serious problem right now, it doesn’t seem to me that the way to solve that problem is to wait 20 years for vertical bulkheads to decay,” Leffingwell said. “Maybe it’s to address how the excessively large waves originate.”

 

Mayor Pro Tem Mike Martinez agreed, saying that he needed more time to learn about the issue. He made a motion to postpone voting on the ordinance until the Nov. 18 Council meeting and to direct staff to bring back a new proposal that would make clear that the new rules wouldn’t apply to pre-existing bulkheads and docks, that site-plan exemptions would apply for maintenance on those pre-existing bulkheads, and that homeowners would be allowed to recapture – or fill in – land lost to shoreline erosion.

 

Before voting on Martinez’s motion, Council Member Laura Morrison wanted to know if it would be possible to get an engineering analysis done to determine what portion of the wave/erosion problem is the result of big wakes from boats and what portion is a result of the reflective waves amplified by the vertical bulkheads.

 

Pat Murphy, the city’s environmental officer, told Morrison that his department would look into the feasibility of such a study. In the meantime, he said, “We believe that these proposals we’re promoting will be much more sustainable long term than the vertical bulkheading we’ve been seeing on the lake. These approaches will be more sustainable and less expensive than having to replace vertical bulkheading and repair it because it’s undermined by the waves.”

 

Council voted unanimously in favor of Martinez’s motion. Staff will report back on Nov. 18.