The Haster Pump Station, Retarding Basin and Recreational Field Project is an integrated flood control project and recreational use area incorporating a two-acre soccer field, three-quarter-mile jogging path, 11 exercise stations, and two cantilevered shade structures within a flood control facility capable of managing 100-year flood inflows of 2,100 cubic feet per second.
The Shimmick team was committed to providing integrated flood control protection and recreational area where the nearby residents can enjoy life for years to come. This community improvement/vision was the project team’s foundation for success throughout the entire project.
The project team’s monumental challenge was to construct a 700-foot triple box culvert, deepen the bottom of the existing basin by 8 feet and build the 110-by-75-by-70-foot pump station 25 feet below existing ground water surface, all while remaining in a “live” flood control basin with a tributary area over 1,800 acres. All phases of construction and planning accommodated, diverted, and discharged up to 460 CFS flows around the work and into the downstream Wintersburg channel while also minimizing disturbance to residents surrounding the entire construction site.
Shimmick worked jointly with AKM design, AECOM, and OC public Works to save over $150,000 in structure excavation costs at the three RCB and gain six weeks in the schedule. In addition, the project team pre-planned and placed the entire three RCB invert using starter walls in less than two weeks to protect the excavation and gravel bedding from storm damage.
The existing basin was deepened by 8 feet requiring more than 199,000 cubic yards of excavation. A large sump pump system, dewatering channels, and elevated haul roads were used to dewater the existing basin without the use significant perimeter dewatering wells. Thus limiting potential settlement impacts to the surrounding residential homes.
Shimmick worked with the owner and designers to re-engineer the pump station excavation and shoring plan to save two months of construction schedule and considerable noise impacts and vibrations to nearby residents. The revised shoring plan was a great success and could not have been accomplished in the needed time frame without positive partnering and teamwork from all parties.
We also partnered to deliver an integrated flood control project and recreational area on-time, under-budget and with Zero recordables and Zero lost-time incidents. The community received a multi-use project with state-of-the-art recreational amenities and improved flood protection for future generations to enjoy for years to come.
