Buckman board hears alternatives to keep sediment out of Rio Grande intake

On Dec. 4, 2025, the Buckman Direct Diversion Board in Santa Fe heard a detailed technical briefing from AECOM and Wright Water Engineers on sediment transport near the BDD Rio Grande intake and a range of design options intended to reduce sediment entering the diversion.

The presentation, given by John Sephora of AECOM and Wayne Lorenz of Wright Water Engineers, explained that sediment in the river is highly variable and concentrated near the bed. "The BDD intake is taking water from the entire water column, and mainly from the bottom," Sephora said, noting measurements that showed average suspended-sediment concentrations and large differences between the bottom and the top six inches of the water column. Wayne Lorenz added that the team’s goal is to ‘‘exclude the sediment, keep it in the river, not take it in," rather than rely solely on downstream separators.

The presentation laid out several alternatives for limiting sediment at the intake: moving the intake farther into the channel, off-channel depositional bays, horizontal ‘‘rainy wells’’ that draw cleaner subsurface water, infiltration galleries and submerged suction bells that capture the top of the water column. Engineers also described screening and species-exclusion methods, including coanda and cylindrical screens and an emerging bioacoustic fish fence — a bubble curtain combined with underwater speakers and strobe lights used to deter fish — and intake gate options such as hinge-crest and Obermeyer gates that can target the top six inches of the river.

Brad, the facilities manager, and consultants noted that LACOE separators installed in the original design were intended primarily for sands, while the finer particles the team observed require a different approach. The presenters cited historical data (USGS records going back to 1973 at the Ottaway Bridge) and stressed that the main differences are in interpretation of long-term data and new, additional monitoring.

Board members asked about maintenance, permit footprints under NEPA, costs, and who would design and oversee the work. Project consultants said they would develop 3–5 combined alternatives and a multi-criteria decision analysis weighing upfront cost, longevity and operations and maintenance before recommending a path to a 30% design and any procurement steps. Chair Green suggested a small pre-vetting group to help board members become more familiar with technical trade-offs; some members cautioned that non-experts should not supplant engineers’ roles.

The board did not take a formal vote on a specific design at the meeting. Presenters estimated the alternatives analysis would take a few months; staff said they would return with narrowed options and cost/maintenance trade-offs for board review.

Next steps: staff and the owner’s representative will prepare an alternatives analysis and bring 2–3 recommended options back to the board for further decision-making and possible solicitation of design services.