Warr Acres staff outline emergency repair, master‑plan steps after sinkhole exposes interceptor line
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Summary
Engineers told the City Council the main sanitary interceptor had extensive corrosion and a sinkhole near a removed power pole. Repairs were estimated at up to about $619,000 for a 140‑foot replacement; the city plans a larger, OWRB‑funded project to replace 790 feet of interceptor and upsizes to 27 inches, and to seek ODEQ/OWRB review and bids.
City engineering consultants told the Warr Acres City Council and Public Works Authority on Feb. 18 that a sinkhole discovered after a utility pole was removed exposed severe corrosion in a main sanitary interceptor and prompted an emergency investigation and repair plan.
Amanda Way, project manager for SRB, said CCTV inspection found the top of the interceptor pipe essentially missing at the damage site. SRB and contractor Cimarron Construction concluded the damaged segment between manholes would require full replacement; Cimarron’s conservative estimate for the emergency repair was $619,000, with a best‑case lower bound of roughly $500,000 if nothing unexpected occurred.
The interceptor in that area carries roughly 3 million gallons per day on average, with reported peak flows to about 6 million gallons per day and storm‑event surges as high as 7–14 million gallons depending on rainfall. The line carries flow from parts of Warr Acres and from Bethany to Oklahoma City’s Deer Creek treatment facility; Way said a failure there could produce an unpermitted discharge and downstream impacts to a nearby lake and creek.
Because the city lacks funds to fully cover an emergency replacement and OWRB emergency grant caps are far lower than the estimate, SRB proposed a phased approach: design and submit an engineering report to ODEQ and OWRB to support a larger, loan‑funded project under the city’s existing $10.2 million OWRB clean‑water loan. The proposed project would replace about 790 linear feet of interceptor and upsize the pipe to 27 inches; the work would also tie into planned repairs on the dam spillway at Pines East Lake. Way said she planned to submit a draft engineering report to regulators and bring final plans and bid documents to council for approval next month if possible.
Public‑works staff said bypass pumps remain on standby and the city continues to rent pumps to maintain service in the short term while design and permitting proceed. Way and staff said the city may need one additional change order to reconcile final contractor quantities on the current 2022 sewer rehabilitation contract; council approved the existing change order to reconcile quantities on the nearly completed 2022 sanitary sewer improvements project.
Way said much of the city’s network is being reviewed through a 2024 sanitary‑sewer evaluation (SSES) and CCTV program; SRB has more than 600 videos to review and expects to publish mapping and priority recommendations later this year. She told council the dam project has been classified a “high‑hazard” dam and that the city is coordinating reviews with OWRB and the U.S. Army Corps of Engineers. Council asked staff to prioritize the most critical “red” segments identified by CCTV and to return with a funding and schedule recommendation.
Council approved the change order formalizing quantities for the 2022 sanitary sewer project and voted to proceed with the next engineering steps for the Pines Dam/interceptor project as staff develop final designs and regulatory submittals.
