Mullan Storm Water Improvement Project

Mullan, Idaho

PROJECT OVERVIEW

In the spring of 1997, Mill Creek flooded part of the City of Mullan, damaging public and private property. Welch, Comer & Associates, Inc. provided professional services to the City of Mullan for completion of a storm water conveyance system to protect the City against future flood damage from Mill Creek. Welch Comer's services ranged from assistance obtaining grant funds to engineering design, assistance with easement acquisition, and construction management to assure the system was constructed in accordance with design. The complete storm system consisted of an earthen intake structure located in Mill Creek near the City's south limits and a 36-inch fused high density polyethylene (HDPE) pipe. The pipeline from the intake structure to an outfall structure at the South Fork of the Coeur d'Alene River.

Welch Comer combined the storm system's design and construction with a concurrent domestic water improvement project, which resulted in less disruption for the local residents and more efficient use of local, state, and federal funding for both projects. The combined project had three separate funding agencies and two different owners. Close project coordination and management was necessary due to the complexity of multiple funding resources and owners.

KEY ELEMENTS

  • 36-inch Diameter Fused High Density Polyethylene Pipe in a Narrow Street with Multiple Utilities
  • Earthen Intake Structure Constructed in Mill Creek Outfall Structure to the South Fork of the Coeur d'Alene River
  • Coordination with Multiple Governmental Agencies such as the Army Corps of Engineers, Idaho Department of Lands, and Idaho Department of Fish and Game Coordination with Multiple Funding Agencies as well as Two Owners
  • Resolution of a Long-standing Flood Hazard for the City of Mullan

 

Placing HDPE