Great_northern_detention_pond
Stephanie Lott [Email address: Stephanie.Lott #AT# ci.austin.tx.us - replace #AT# with @ ]

City of Austin, Watershed Protection and Development Review Department

Many residents in the Allandale Neighborhood have taken the time to contact the City of Austin or the Allandale Neighborhood Association about this project. A big “thank-you” is due to all who have been involved and have made suggestions to improve this project.

The City of Austin has been able to incorporate many of these suggestions into the project, including:
•    Preparing an area for the neighborhood to install stretching equipment.
•    Improving drainage to reduce the mud on the east shoulder of Great Northern Boulevard, a temporary fix that should last a few years.
•    Replacing the old, dilapidated bollard and wire barrier.
•    Improving the safety of the sidewalk entrance at Great Northern Boulevard.
•    Installing a wheel-chair accessible bench area by a shade tree.
•    Planting more than 100 shade and ornamental trees to help compensate for the ones removed. The trees will be strategically placed in areas where they will not compromise the safety of the dam, but will help shade portions of the sidewalk and screen some neighboring properties.

In addition, the City has incorporated a custom stamp of a pre-historic
plesiosaur and ammonites into the design for the top of the spillway to
evoke the natural history of the area. It is important to note that
these stamps are ones that are commercially available and do not
necessarily reflect specific fossil types found in the area.

Construction Information
Depending on how long the permitting process lasts, construction is
expected to start between October and January and will last about nine
months. During construction, access to the site will be limited,
although it will always be possible to go between the pedestrian bridge
and Great Northern Boulevard. The City of Austin will hold another
public meeting before construction begins.

Project Purpose
This is a project to make safety improvements at the Great Northern
Detention Pond (also called the Far West Dam). This site is technically
a dam. It controls the flow of flood waters into Shoal Creek during
severe storms and reduces the risk of flooding for many homes in the
Allandale Neighborhood. The adjacent water quality pond helps remove
pollutants from storm water runoff before it reaches the creek.

Although the dam is in good condition, it was originally constructed in
1978 to the standards at the time and does not meet current state
safety requirements. The City of Austin is planning to upgrade the site
to current standards and has been working with the neighborhood since
January on this project.

The safety improvements will require the removal of many trees on the
site that potentially threaten the structure of the dam. It will also
require the construction of a large, concrete-lined spillway and a
concrete wall at the top of the embankment to help direct flood waters.
The wall will vary between about one foot and three feet high and will
not prevent access to the pond area. The City is also planning to add
an access road to the pond to aid in future maintenance as well as a
Flood Early Warning System gauge to help monitor the water level in the
detention pond.

There is more information on the City of Austin’s web site at
www.cityofaustin.org/watershed/flood_pond_great_northern.htm. Or you
may call the Watershed Engineering Division of the Watershed Protection
and Development Review Department at 974-3371.