Northern Arapaho Tribe Utility System Assessment

Riverton, WY

In 2020, Inberg-Miller Engineers performed a comprehensive water and sewer system utility assessment and mapping project for the Northern Arapahoe Tribe. The engineering study involved water system well production, treatment, storage, and water distribution system and pressure zone modeling. The study also included individual component evaluation of well controls, treatment, water storage, and pressure regulating valves and prioritized improvements.

The same study reviewed several miles of sewer collection lines, manhole conditions, sewage pump stations, and sewage treatment and lagoon needs. Numerous sewage lift stations were evaluated for remaining life, safety, capacity, and repair parts availability

The resulting study outlined over $10,000,000 in water and sewer improvements that were required to obtain a level of service required by the client. The water and sewer systems demands and designs were completely evaluated to current EPA and Wyoming DEQ requirements.

As a follow up to the assessment, Inberg-Miller Engineers designed a new sewage lift station. The existing lift station and lagoon were located within a floodplain therefore analysis was required to consider the effects of a 100-year flood on the facility.  

The lift station designed was a duplex submersible pump system with a separate valve pit designed for peak flows, all meeting Wyoming DEQ Chapter 11 requirements.

Our project objectives achieved included:

  • To collect and compile existing water and sewer system information into one complete data source and model. 
  • Increase the Tribe’s ability to efficiently manage the systems’ maintenance and emergency repairs and prioritize future upgrades to the water and sewer systems using our base map and condition assessment.
  • Support enforcing tribally enacted Indian Preference law (TERO) to ensure that Indian/Alaska Native people gain their rightful share to employment, training, contracting, subcontracting, and business opportunities on and near reservations and native villages.