NRCS Increases Safety with Infrastructure Upgrades in Oklahoma

For 8 years, Affinis has been working with the Natural Resources Conservation Service (NRCS) on a variety of projects. Together, we’ve partnered to improve infrastructure, increasing safety for communities across the Midwest.

While their goals remain the same, they are moving with increased urgency to tackle their aging facilities. Today, we’re excited to highlight some of our recent work in Oklahoma. All these projects range in stages of completion. One is ready for construction, while another was just recently started.

Caston Mountain 2 Dam Rehabilitation Design
Located in Oklahoma, the Caston Mountain 2 Dam was originally constructed decades ago. To meet current safety standards for high-hazard dams, it needed updates that would extend the life of the dam by another 100 years and improve its ability to protect downstream communities.

For this project, our engineers helped evaluate and design key features of the rehabilitation, including updates to the principal spillway and other structural elements. Our approach focused on enhancing safety, improving flood protection performance, and identifying efficient, cost-effective solutions that preserve the dam’s long-term integrity.

Caston Mountain 1 Dam Rehabilitation Design
The Caston Mountain 1 Dam was originally constructed in 1972 as a low hazard structure. The dam had been reclassified as a high hazard structure due to downstream development, and the structure has reached it 50-year design life. Our team was tasked with extending the design life of the dam and bringing it up to meet applicable standards for high hazard dams. For this effort, we performed extensive subsurface and topographical investigations of the area and are currently designing structural renovations. Our design includes a new intake tower, impact basin, and auxiliary spillway.

Spavinaw Creek Preliminary Investigation Findings Report (PIFR)
Spavinaw Creek is located between Eucha Dam and Spavinaw Lake on Cherokee land in Oklahoma. The reach of Spavinaw Creek, immediately downstream of Eucha Dam, is experiencing accelerated streambank erosion, resulting in active bank failure that threatens adjacent residential structures and reduces water quality due to increased sediment loads. NRCS recently asked our team to prepare a Preliminary Investigation Findings Report (PIFR). A PIFR is a planning report, to be completed in 90 days, that explores NRCS authority and recommends federal interest in a NRCS project.

To prepare the PIFR, we were asked to look at ways to mitigate damage from erosion and determine if the federal government should have an interest in this project. We gathered data for the project by studying maps of the area and meeting with local residents. We also plan to speak with stakeholders from the Oklahoma Department of Transportation, collecting their input regarding a bridge on-site. This information will be incorporated into the PIFR, along with recommendations on next steps for NRCS.

Quapaw Creek Site 15M Dam Rehabilitation
Nearby downstream development has caused the aging dam in Quapaw, Oklahoma to be reclassified as high hazard. Currently, our team is working on the structural design for a new, roller compacted concrete spillway to bring the dam into compliance with NRCS TR-60 standards and other relevant state and federal policy and design standards. Geologic conditions at the site prevent increasing reservoir capacity. The new design will increase safety and accommodate the area’s evolving needs by increasing the dam’s ability to safely pass flood events through the dam, without overtopping.