[provided by TM 5/13/04] three additional documents mentioned now available
Blunn Creek Walkabout 2 – Summary: May 6, 2004
Attendees: David Todd, Karen Marks, Tim Mahoney, Monte Youngs, Neal Nuwash, David Swann, David Karoly, Dawn Cizmar, Matt Hollon and Garret Nick
Others: Mike Lyday, the City’s Creek Biologist (City of Austin’s Watershed Protection and Development Review Dept.)
City Staff: Adam Smith and Scott Whiteman
Overview: This is the second of three Blunn Creek Walkabouts. It is hoped that the third will be scheduled later in May. It appears that the Creek is healthier, as to wildlife and natural vegetation, in the upper watershed area than in the areas around Big and Little Stacey Park.
The walkabout started near the intersection of the creek with Ben White Boulevard and ended just north of Woodward within St. Edward’s property.
In an effort to avoid redundancy, only those topics not discussed at the previous, April 21, 2004 Blunn Creek walkabout (which covered the area from Pecan Grove to Fairmount) will be given here.
Headwater Protection Ordinance
A Headwater Protection Ordinance is currently being developed. The goal of the Headwater Protection ordinance is to protect more waterways by reducing the minimum drainage basin area requirements. The details of the proposed ordinance are still being discussed. It is hoped that Mike Lyday will be able to assist with some technical aspects of watershed protection.
The Southeast Combined Neighborhood Planning Area incorporated principles of the Headwater Protection ordinance into their plan. Attendees at the walkabout expressed interest in doing something similar in the Greater South River City plan.
Headwater Detention Facility
There is strong interest among the SRCC members and residents in exploring protection of the AISD parcel as an undeveloped site, with detention facility, to the south of the east end of Alpine, to the north of Ben White, and west of IH-35 and Payload Pass, at the headwaters of Blunn Creek. This parcel appears to offer the largest detention basin site to protect the water quality of the Creek, reduce stormwater flows, and allow infiltration and baseflow support. This protection seems particularly important due to the pending development of the Wal Mart site at the northwest corner of Ben White and IH-35, the proposed construction on the adjoining Payload Pass site to the immediate west of the Wal Mart property, and the large-scale, largely unmitigated (beyond installation of energy dissipators) expansion of IH-35 and Ben White. The detention structure installed at the Blunn Creek apartment complex appears to be functioning well, and gives encouragement for the value of a detention basin of some kind on the AISD site.
Please find several related documents attached, including two maps of the Blunn headwaters area, and a spreadsheet comparing various detention sites and demonstrating the high benefit/cost ratio for an AISD detention area.
Critical Water Quality Zones
In an urban watershed (of which Blunn Creek is considered), a critical water quality transition zone is established along each waterway with a drainage area of at least 64 acres. Development within these zones is severely limited. According to Matt Hollon's new estimate of the boundaries of the Blunn basin, especially with the addition of contributing watershed south of Ben White, the basin now easily exceeds the 64-acre threshhold.
Wetland hydrology and vegetation
An area will be extended greater protections if it is identified as being a wetland. From time to time there is debate on determining if an area truly is a wetland. The types of vegetation growing in an area is used in determining whether a wetland is present. Obligate vegetative species (species that only grow in wetlands as opposed to facultative species that can grow in wet and dry conditions) is a strong indication that wetlands are present. Some obligate species are growing along Blunn Creek, including juncus, water primrose, water dock, cattail, spike rush, watercress, and water hyssop. The wetland vegetation appears to be supported by base flow, since it has been more than a week since the last rain, and the creek is 4 to 12" deep in water, with the stream ranging from 2 feet wide (near Alpine) to 4 feet wide (near Woodward).
Wildlife
It was encouraging to see a good deal of wildlife in the creek, including small fish (mosquitofish, perch, perhaps), three large, 16-inch long snapping turtles, and a green heron, suggesting that the water quality is good and the base flow consistent. In addition, numerous crawfish burrow holes were spotted in this section of the Creek, no doubt feeding on small fish populations and in turn providing a food source for the turtles. Such habitat could be replicated downstream in the Stacy Parks with the additions of such technical structures as grade controls and riffle-pool complexes. These structures, which are being planned for Boggy Creek and the creeks through Mabel Davis Park, would not only reinforce the natural stability of the Creek, but allow a more dynamic return of wildlife, fauna and flora.
St. Edward’s University
There is concern that St. Edward's is planning to double the campus enrollment, and expand parking and ballfields in the eastern part of the campus, perhaps in the area that forms the Blunn Creek riparian zone. There is hope that St. Edward's new biology building and program will incorporate use and study of the Creek. It is unclear what the current status of the St. Edward's detention project is, though one is rumored to be under development.