Opportunity Ponds Remedial Action/Design

Pioneer has led the design and construction of some of the largest wetland creation, restoration, and enhancement projects in the northwestern United States. With experience in both wetland mitigation and wetland resource preservation, we can help clients restore damages caused by past land use and prevent impacts from future use. Wetland mitigation services include a staff of highly trained field support personnel that can perform in-depth wetland quality monitoring and FEWA assessments. Our team of wetland experts have the experience necessary to successfully guide clients through the many regulatory processes and into the design, construction, development and monitoring of high quality, functioning wetlands.

Since 1999, Pioneer has provided remedial design, contract development and administration, project management, and construction oversight services for remedial action activities at the 55,000-acre Anaconda Regional Water, Waste, and Soils and Operable Unit (ARWW&S OU) Superfund Site. Several projects have been completed, or are near completion, including the Opportunity Ponds Remedial Action project.

The Opportunity Ponds project included installing and revegetating approximately 3,200 acres of Engineered Cover over the existing tailings impoundment and surrounding impacted areas, using approximately 10 million cubic yards of cover soil and treated media.  We designed and developed specific on-site soil borrow areas to create approximately 600 acres of diverse wetland habitat for basin-wide Functional Effective Wetlands Area (FEWA) mitigation.  The design includes approximately 5 miles of storm water conveyance channels, 60 acres of storm water retention ponds, and corresponding hydraulic control structures to convey storm water from a 10,000-acre drainage area.

The project also included the design and construction of a groundwater treatment system to treat contaminated groundwater emanating from below the tailings impoundment using passive co-precipitation of iron and arsenic enriched waters.  We designed the Opportunity Ponds system to intercept and collect groundwater contaminants, primarily arsenic and iron, migrating from under the Opportunity Ponds waste management area. Two surface water discharges (decant outlets) were used to decant process water from the tailings ponds. The system consisted of 5,700 linear feet of interceptor trench, 7,000 linear feet of retention pond, 1 conveyance channel, and 3 outflow structures.

Pioneer was responsible for the project design, contract development, project management, and full-time quality assurance during the 5-year construction project.