City official outlines how San Juan‑Chama return‑flow project could stretch local water supplies

Jesse Roach, a City of Santa Fe water utility staff member, told commissioners that the city’s drinking water system relies on four potable sources — the Santa Fe River and its reservoirs, city production wells, the Buckman well field and the Buckman Direct Diversion (BDD) — and a separate non‑potable reuse program that irrigates parks and golf courses.

Roach said the city shifted in 2011 to using surface water preferentially through the BDD and has seen groundwater levels recover: “we’ve seen the city wells have recovered 60 feet of that 150,” he said, adding that the Buckman wells have recovered roughly 510 feet in pressure losses since the shift. He told the board the change reduced total annual production from a 1995 peak of about 13,000 acre‑feet to roughly 9,000 acre‑feet while the population served grew by about 25 percent.

The presentation placed particular emphasis on the San Juan‑Chama Return Flow Project, a planned pipeline and operations change intended to return treated San Juan‑Chama‑derived effluent to the Rio Grande below the BDD intake. Roach said the project is intended to generate return‑flow credits so the same volume of diverted San Juan‑Chama water can be made to “go three times farther.” “On an annual average, about two‑thirds of the water that we produce ends up back at the wastewater treatment plant,” Roach said, and returning that portion to the river would reduce upstream reservoir releases required to keep the downstream river whole at the diversion point.

Roach and commissioners discussed the difference between water rights on paper and physical (wet) water, how the shared‑pool accounting at BDD allows the city and county to exchange diversions, and why the return‑flow option was chosen over purple‑pipe distributed reuse or direct potable reuse. Roach said the return‑flow alternative made it possible to leverage existing infrastructure (BDD and the city’s treatment plant) and was preferred because it is less costly and technologically uncertain than direct potable reuse.

Roach described the city’s long‑range planning work with the county (a project called Santa Fe 2100) that models demand and supply out to 2100 using downscaled climate projections and system models to identify shortages and adaptation options. He cautioned that uncertainty in long‑range hydrology means modeled benefits are not guarantees, but that the return‑flow project, if permitted and built, could “buy a little breathing room” by increasing sustainable available supply in near‑term scenarios.

Commissioners and members of the public raised questions about handouts, how development approvals connect to water availability, whether San Juan‑Chama water is available for purchase or lease, and how the return‑flow project would operate seasonally; Roach answered with technical details about the BDD accounting, the annual‑average math behind return flows and the city‑county agreements that establish credits and cost‑sharing.