Repurposing a Dry Pit Reduces Construction Costs and Increases Operational Flexibility at Topeka’s Ash Street Pump Station

The Ash Street Pump Station in the City of Topeka, Kansas was expanded to accommodate growth and development in Topeka. The City and Bartlett & West collaborated to evaluate alternatives and complete an innovative design that decreased construction complexity, and saved $600,000 compared to the conventional expansion approach originally envisioned.The goal of the project was to expand the existing pump station capacity from 1.49 m3/s (34-mgd) to 3. m3/s (74-mgd). However, the design of the current pump station provided for expansion only up to 2.19 m3/s (50-mgd), and available space for expansion was quite restricted. Space restrictions were overcome by repurposing the abandoned dry pit portion of the original, oldest part of the pump station site to accept installation of three 200 horsepower, 0.53 m3/s (12-mgd) vertical turbine solids handling (VTSH) pumps. This essentially created two pump stations at the same site.This solution provided the following important benefits:Elimination of extensive piping modifications of the existing pump station;Elimination of pump station shut-down and greatly reduced bypass pumping operations during construction;Operational flexibility by now allowing one of the pump stations to be taken off line for maintenance while still maintaining adequate capacity for normal operations; andSpace remains for an additional future expansion to the full 3.24 m3/s (74-mgd) firm capacity through the addition of a fifth pump at the existing pump station.The expanded pump station has been in operation since 2007. The design exceeded the expectations of the City. A facility of greater value was constructed for a cost far less than originally anticipated.