Meeting with the City of Austin

Proposed Route of Drainage Pipe:

COA Meeting 12/6/07

The Drainage Committee met with the City of Austin on 12/6/7 for an update on phase one of the drainage project. Phase one will add an additional covered drainage pipe under White Rock between Woodview Avenue and Shoal Creek. Subsequent phases will make improvements upstream.

After receiving feedback at the ANA meeting in the Fall and reviewing their flow rate calculations, the City paused the project in order to perform additional analysis. There was a significant difference between the capacity of the original design and the calculated flow rates for 25 and 100 flood events. The City is looking at ways to increase the water captured on White Rock and the impact of capturing additional water on the total watershed.

The City has hired an outside consulting firm to determine the maximum amount of water that can be diverted without causing problems where the water will enter Shoal Creek at White Rock.

With this information, they will determine the maximum size of the new drainage pipe to be put under White Rock. The City noted that the size of the pipe may be further constrained by existing utilities currently under the road.

The City also gave us an update on the storage facility behind White Horse Trail, Nasco and Twin Oaks. It is still cost prohibitive for them to convert part of this facility into a retention pond, and they have reviewed historical planning applications to ensure that the current site complies with these plans. John Panak (ANA) identified an apparent discrepancy to the plans, and although it is fairly minor the City said that they would follow-up with the storage facility.

The Drainage Committee expects to meet with the City of Austin again sometime on February after this analysis has been completed. The updated schedule for phase one of the project is to complete the design by the end of May, and then have a five month bid process.

Update from COA

I spoke with Stephanie Lott (City of Austin) today to get an update. Here's what she said.

• The bid opening has been delayed to allow the city to investigate adding more capacity to the culvert at White Rock and to have another look at the possibility of adding a detention pond.

I asked Stephanie if she would be able to provide more information on the following

• Information about updates to the project as they become available
  
• The anticipated impact at Shoal Creek where the water will enter the creek
• If the project will address the erosion issues at the culvert on Bull Creek between White Rock and 2222. (I also committed to find out more information about this and pass it on to her.)
• Review the storage facility agreements with the city. A resident has informed me that they believe that the storage facility was supposed to include a retention pond when it was converted from a drive in movie theater.
• Another resident contacted me about the land between White Horse Trail and the storage facility. They believe that there is a relatively small piece of commercial land that is not heavily used that might be a possible site for a retention pond. I also noted that this isn't the official position of the ANA; at this point I am just passing on comments.

She though that she would be able to provide more information in a few days.

ANA Meeting, August 2007

The City of Austin gave a brief presentation on their plans and answered some questions at the ANA meeting in August. I wasn't involved with the Drainage Committee at the time, so didn't take notes. Here's my best recollection of the highlights.

• The project is intended to improve drainage around Bull Creek road between White Horse Trail and FM2222.
• There is somewhere around $8M earmarked for the project.
• The first phase of the project will install a new 3 foot by 6 foot covered boxed culvert under White Rock road starting somewhere around Woodview. It will run under to White Rock and empty into Shoal Creek. There will be series of drains entering the new pipe and a new culvert will be added to the drainage ditch between Woodview and Bull Creek at White Rock. (The existing culvert will also remain in place.) This phase is scheduled for completion in the first half of 2008.
• The master plan included adding a drainage pond to the self-storage facility (on Burnet) that backs onto the drainage ditch. This plan has been abandoned because the cost of purchasing the land is much higher than originally estimated, and the city is looking for other options.
• A second phase plans to add another covered box culvert running along White Horse Trail with inlet drains. It didn't seem like plans for this phase were finalized. However, the city representatives gave assurances that funds have been allocated for this phase. It's just a matter of creating the best plan now that a drainage pond is not an option.

Concerns expressed by Allendale residents.

• There was some concern that the city has underestimated the amount of water that flows through the drainage ditch between White Rock and Woodview.
• Residents near the spot where the new pipe will empty into Shoal Creed expressed concerns about how this may effect the water level in Shoal Creek.
• Residents backing onto the storage facility on Burnet expressed concerns about how water is currently draining from that property.

The city noted these concerns.

City of Austin Contacts

Staff from the City of Austin presented an overview of their drainage plans at an ANA meeting in August. The City of Austin team included

Stephanie Lott
Public Information Specialist Senior
(512) 974-2799
stephanie@ci.austin.tx.us

Jennifer C. Liu, P.E.
Engineer C - Team Leader
(512) 974-7159
jennifer.liu@ci.austin.tx.us

George E. Oswald, P.E., D. WRE
Engineering Division Manager
(512) 974-3369
george.oswald@ci.austin.tx.us

Glen Taffinder, P.E.
Engineer C
(512) 974-3381
glen.taffinder@ci.austin.tx.us

Thu A. Cao, P.E.
Engineer
(512) 974-7167
thu.cao@ci.austin.tx.us