Client: SRK Consulting 

Location: Arizona 

  • 19 square miles of watershed 
  • 8,900+ ft of channel 
  • 1,500 ft of spillway 
  • 48 spillway design options 
  • 176 channel design options 
  • 240 total stormwater management options 

Project Overview:

An inactive large mining site has significantly altered the natural watercourse and landscape over the course of its mine life. In order to permanently close the site, it must be reclaimed in a manner that is environmentally responsible, restores surface flows to pre-mine conditions, and is safe to the public and surrounding communities.

As part of the reclamation efforts, Riley designed surface stormwater control structures (channels and spillway) for floods ranging from the 1,000-year event to the Probable Maximum Flood event to mitigate flood risk to neighboring communities. Of particular concern for this project is the increasing uncertainty of climate change which Riley accounted for in the design of the stormwater control structures. To evaluate the feasibility of the design options, Riley developed a multi-criteria analysis matrix, providing the client with a safe and cost-effective approach for reclamation.