November 12, 2009
Mayor & Council Members, City of Austin
P.O. Box 1088
Austin, Texas 78767
Reference: Barton Springs Pool gravel bar must be removed.
We write to support the city staff’s plan to remove the gravel bar from Barton Springs Pool. The gravel bar is a large collection of flood debris (1500 cubic yards of gravel and boulders, and growing) that is spread over the downstream portion of the pool. The Barton Springs Pool Master Plan, which was developed to end decades of neglect at the pool, rightly calls for removing the gravel bar.
Removing the gravel bar is part of an overall effort to restore the pool to a more natural state. In a natural free-flowing creek, the flood debris would be washed down the creek. Instead, the dam that forms Barton Springs Pool traps the flood debris, and the flood debris acts as a second dam, trapping more flood debris.
Here, we offer answers for a few questions we have received regarding removing the Barton Springs Pool gravel bar.
Q: Is the gravel removal project a Monster Dredging process that will kill every living thing in the dredge zone?
A: Absolutely not. The gravel removal project is driven by the need to return the pool to a more natural state. There is nothing natural about the gravel bar: it is a huge pile of rocks, sludge and sediment washing from upstream against a man-made dam, and it is filling the deep end of the pool. The accumulated gravel has covered and suffocated the aquatic life that once inhabited the pool bottom in that area. The ecosystem of the pool is managed by Watershed as part of the mandate to protect the salamander. They have introduced plants and will continue to work towards promoting the growth of plant and animal life in the pool that will improve the conditions for salamander habitat and not interfere with the swimmers.
Q: How will the Pool benefit from the gravel removal project?
A: It will make the pool cleaner and easier to keep clean. This project will increase water flow in Barton Springs Pool. If left to its own devices, the pool will eventually fill completely with sediment that make up the gravel bar (silt, rocks, and boulders), and we can go and hang out on the Barton Springs Gravel Bar, because there will be no pool. The amount of time for this to occur can be calculated by simply dividing the volume of the pool by the volume of total accumulated sediments, and then multiplied by the time it took for that volume of sediments to collect. The removal of the gravel bar has the potential to reduce the amount of silt kicked up by swimmers during high use times because the silt would be in 10-15 ft. deep water. It also provides the opportunity to explore more routine methods for management of sediment accumulation in the pool during spring cleaning and the weekly Thursday closing of the pool for cleaning. Continue reading “Gravel Bar Q&A”