Shoal Creek’s Situation

A dry Shoal Creek during the drought of 2011

Any vision for Shoal Creek begins with a litany of complaints. Complaints are cathartic; let’s get them out of the system. Forget who is to blame. I promise once disgorged I will let them be.

Shoal Creek suffers from acts of omission, not commission. There are exceptions, but in general Shoal Creek has been seen as a void to fill with the detritus of urban life. Let’s look at the detritus.

  • Low sustained flows
  • Shoal Creek once ran as vigorously as Barton Creek. Developers once eyed Seider’s Springs for a lakeside development. The steady flows are gone, victimized by development and myopic public works projects.

  • High peak flows
  • Shoal Creek stormwater flowing through Pease Park

    Austin feeds storm water directly into Shoal Creek. Shoal Creek is a stormwater pipe, a conduit for sending water to Lady Bird Lake as rapidly as possible. The increased velocity aggravates streambank erosion and sediment flow.

  • Stormwater detention
  • This is a solution masked as a problem. Little of Shoal Creek’s stormwater is detained up stream. Most is straight piped into the creek. Austin is beginning to look more closely at sustainable stormwater management, but you wouldn’t know it by looking at the creek.

  • Non-point pollution
  • Pollution is drained into the creek by stormwater. The water washing over streets, bridges, parking lots, and back yards reaches the creek unfiltered. Every dog pile left along Shoal Creek will finally make its way to your drinking water. Fertilizer seeps into the creek as well, feeding the various blooms and rank vegetation.

  • Erosion
  • As mentioned above, increased stormwater velocities have left streambanks undermined and eroding.

  • Trash
  • Trash below W 3rd Street Trestle

    Shoal Creek is littered, but in interesting ways. For example, look at the trash that collects under the West 6th Street Bridge. Styrofoam cups and containers, beer cans, liquor bottles, and plastic bags blanket the creek there. The same is true for the creek below the HEB near Seider’s Springs, although most of the garbage there is plastic bags. I would add tagging (crude graffiti) to the list of what should be considered trash.

  • Bad Ideas Gone Wrong
  • The drought of 2011 exposed the creek in ways I had not seen before in my 17 years of living along the creek. Every screwy idea implemented in the past has been on display. The pièce de résistance is the waste water pipe running down the center of the creek bed (look for the concrete box). Below West 3rd you see the remnants of the Green Water Treatment Plant, the Seaholm Power Plant, and the diversion of the mouth of Shoal Creek at Lady Bird Lake. Yes, these are acts of commission.

  • Lack of Maintenance
  • Shoal Creek, looking north from Gaston, with vegetation encroaching on the streambed

    The drought has done more than dry out Shoal Creek. The drought has accelerated the growth of trees and shrubs within the streambed itself. This vegetation restricts flow when the creek is needed to carry stormwater. This rank growth is most obvious around the many bridges on Shoal, obscuring some of Austin’s most interesting historical structures. Shoaling is most pronounced about the bridges, another sign of a lack of maintenance. Trails are eroded, uneven, and trail surfaces range from concrete to dirt.

  • Wildlife Corridor
  • Shoal Creek is a ribbon of green bisecting one of America’s fastest growing cities. The trees and shrubs that border the creek provide wildlife with a corridor of essential habitat. The value of this corridor is directly related to its continuity. Development threatens to interrupt this ecological continuum, creating sections across which wildlife will not or cannot pass.

    Trust me; none of these challenges is insolvable. There are solutions for every conundrum. The question is whether or not we (we as in Austin) have the will. Let’s start over.

  • Low sustained flows
  • High peak flows
  • Stormwater detention
  • Non-point pollution
  • Erosion
  • The same approach addresses these five problems – sustainable stormwater management. I love Portland’s approach – maximize permeability, minimize offsite storage. Detention ponds, bioremediation wetlands, stormwater swales, rain gardens, and structural soil all have a role in sustainable stormwater management. What is not needed is more straight pipes to the creek. The goal should be to trap every gallon of water upstream, and then to slowly release it downstream to insure a sustainable low flow. Develop enough retention (in its broadest sense) to capture the 10-year maximum rainfall event.

    I suspect that detention and retention will not be enough to sustain a low flow. Therefore we need to work with the city to redirect water from Lady Bird Lake to Shoal Creek. No, I am not envisioning the San Antonio River Walk. But surely we can find a way to pump water from the lake to a point up Shoal Creek (West 24th, for example?) and then let that water flow back.

    As for trash, the solution is simple. Let’s keep our crap out of the creek. No one forces us to fling garbage into the creek. There is no gun held to our heads. If a dog craps, clean it up. If you are finished with your half gallon of Jack Daniels, throw the bottle into the receptacle.

    Let’s keep our crap out of the creek

    Magnolia blossom with green anole within the Shoal Creek Corridor

    Bad ideas can be erased by good ideas. Begin with the simple notion that stormwater can be a design element. Develop a sustainable trail system, one that limits runoff from hardened trail surfaces and uses structural soil to increase permeability. Use retention ponds and vegetated swales as enhancements for wildlife, recreation, and education. Use low level overflow dams for in-stream detention and for creating more permanent pools within the creek itself. In time of drought, these pools are critically important for wildlife. Remove old structures from the creek, vegetation from within the stream bed, and shoaling that now restricts flows. Protect the wildlife corridor, and enforce setback regulations. Revegetate areas where the corridor has been severed.

    The initial goal should be to bring Shoal Creek back to robust health. A restored creek then offers a platform for the types of enhancements that people expect of a world-class city. The next section (Visioning Shoal Creek) will offer suggestions about such enhancements.

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