Secret Ravine Emergency Sewer Main Replacement


Diamond D provided emergency design-build services to replace a badly corroded 1.4 million gallon a day (MGD) 24 inch gravity sewer pipeline that crossed Secret Ravine six feet above the water. There were indications that the pipe could potentially rupture and spill sewage into the ecologically sensitive creek. Diamond D replaced the corroded pipe with a 65 foot length of new 24 inch steel sewer pipe and 30 inch protective steel casing that were put in place with a 140 ton crane. The pipe and protective casing were bolted onto custom fabricated steel saddles securely anchored into concrete and solid rock foundations on both sides of the creek.

There were numerous design and construction challenges to overcome. The flow of sewage could not be cut off or redirected so Diamond D set up a bypass system that diverted and pumped more than 1 MGD of sewage while the corroded pipe was replaced. Heavy fines would be assessed if even a minimal amount of sewage leaked into the creek so the bypass system was monitored around the clock while it operated and an emergency secondary bypass system was also put into place. Residences next to the project were inconvenienced as little as possible by installing cyclone fencing with fabric to screen the project from them. In addition, the project was constructed on a very aggressive schedule so that it could be completed prior to the fall salmon spawning run. Mobilizing a crane to the site with numerous trees that couldn't be removed and very little room to maneuver was also very difficult.


  • Design- build
  • Implement SWPPP
  • Install 1MGD sewer bypass system
  • Monitor bypass system around the clock while in operation
  • Construct temporary bridge
  • Install cyclone fencing and screening fabric
  • Remove corroded sewer line crossing creek
  • Build rock and concrete foundations on both sides of creek
  • Fabricate and anchor steel pipe saddles onto foundations
  • Mobilize 140 ton crane to site
  • Place 65 foot span of 24 inch steel sewer pipe and 30 inch protective casing on steel saddles with crane
  • Secure pipe to saddles and connect sewer line at both ends

Owner: South Placer Municipal Utility District

Contract Value: $480,000 Completion Date: October 15, 2007

Reference: Available Upon Request