City of Austin Rock Harbour Lift Station Improvements

Furthering the City’s Northwest Area Lift Station Improvements

Project Purpose

In 2016 the City of Austin conducted the Northwest Lift Station Study to identify lift station and force main improvements based on condition or capacity needs. As part of this work, the City retained KFA to design one of the improvements: the Rock Harbour Lift Station Improvements project. The purpose of the project is to increase the capacity of the Rock Harbour lift station by constructing a new wet well, valve vault, and electrical improvements that met current City standards.

Project Approach

First KFA completed a feasibility study and preliminary engineering. Then we received authorization to develop detailed design. The design incorporated two phases:

  1. An interim phase, during which the pump station will continue to pump through 4,800 LF of existing 12-inch force main; and
  2. A future phase, where flow from the lift station will be directed to a 16-inch force main about 11,000 feet long.

Our design of the lift station improvements included selecting the pumps and sizing the wet well for the projected future flows. In addition, we designed the layout for the proposed lift station to allow the existing lift station to remain in service during construction. We coordinated with subconsultants for the electrical improvements, structural design, and selection of screening equipment.

Our team provided solutions to the following challenges as part of this project:

  • Due to the different force main configurations, new pumps are required in each phase. We worked with the pump suppliers to select pumps that could work with both phases by trimming the impeller instead of installing new pumps for the future phase.
  • Since the lift station received a large amount of rags, we evaluated macerator units during the preliminary phase. To reduce the amount of space needed to remove the rags, a vertical screening unit was selected during design.

Project Results

For the lift station, KFA submitted 100% design in 2021 including easements and permitting, and construction is expected to be complete by 2025. This project increases capacity for wastewater collection and reduces the risk of wet weather overflows.