During an Oct. 20 Scottsdale City Council meeting, the city’s interim water director, Thyra Ryden‑Diaz, presented a slide titled “Water Deliveries 2021‑25.” The graphic showed five columns of roughly equal height, suggesting that water deliveries would stay flat while the city’s population grew slightly.

Mayor calls for clarification

Mayor Lisa Borowsky labeled the presentation “misleading” and asked City Manager Greg Caton to explain the discrepancy between the council slide and the city’s July 28 Designation of Assured Water Supply (DAWS) application filed with the Arizona Department of Water Resources. The DAWS application projects a 9 % increase in estimated demand from 2024 to 2025 and a total demand of 109,999 acre‑feet by 2036 – a 22 % rise that was not reflected in the council presentation.

“I believe this should be corrected by our city manager because our own Arizona Department of Water Resources application shows increases in water supply delivery projections during the same period, which is confusing and warrants correction one way or the other so we have an accurate reading on future water delivery needs,” Borowsky said after the meeting.

Key figures in the water debate

Ryden‑Diaz also told council members that Scottsdale anticipates a 17 % cut in Colorado River water delivered via the Central Arizona Project (CAP). The city’s DAWS application, however, assumes CAP “water direct delivery” of 77,965 acre‑feet per year for the next 100 years – more than half of the projected 13.8 million acre‑feet total 100‑year volume.

Scottsdale Water spokesman Bryan Bouchard explained that the DAWS numbers were prepared without factoring in potential Colorado River supply reductions because the post‑2026 operating framework had not yet been finalized. “The application was prepared and submitted based on the applicable information and assumptions available at that time,” he said.

Assured supply versus actual use

Ryden‑Diaz emphasized that Scottsdale holds an “assured water supply” of 141,341 acre‑feet, a designation that expires this year. She noted that the city typically uses about 82,000 acre‑feet annually, leaving roughly 58,000 acre‑feet in reserve. Councilwoman Jan Dubauskas echoed this, asking if the city had 50,000‑60,000 acre‑feet of water per year that it was not using. Ryden‑Diaz confirmed the figure and called the surplus “a reserve.”

ASU’s Kyl Center for Water Policy director Sarah Porter disputed the “surplus” characterization, stating that the assured water supply designation is not a guarantee of water availability. “The designation of assured water supply isn’t a guarantee of that water being available. It is a determination … that Scottsdale can meet 100‑year demand of that amount – but that would be subject to the limitations for each water supply,” Porter said.

Drought concerns and future cuts

Porter warned that the Colorado River, which supplies more than two‑thirds of Scottsdale’s water, remains vulnerable. She said a 17 % cut is the best‑case scenario if snowpack is adequate, but deeper cuts could occur if the Upper Rockies experience a poor snow season. “We could get to a point where there is ‘run‑of‑river’ – no more access to stored water,” she cautioned.

Councilwoman Solange Whitehead labeled the city’s “reserve” figure as “false,” arguing that the 50,000‑plus acre‑feet number inflates the actual surplus of 10,000‑20,000 acre‑feet of CAP and recycled water the city has been banking. “Building today’s reserve took decades. With no future CAP surpluses expected, this is an emergency reserve, not a renewable supply,” she said.

Political rhetoric enters the debate

The water controversy has spilled into the local election. The New York Times ran a story titled “‘Poop Water’ Churns a Local Election in Parched Arizona,” noting that Republican candidates Barry Graham and Michelle Ugenti‑Rita have attacked the city’s wastewater recycling program as “toilet‑to‑tap” or “poop water.” Ugenti‑Rita accused the national press of bullying residents with “gross, unproven ‘toilet‑to‑tap’” claims.

Ryden‑Diaz defended the recycling effort, reminding residents that “all water is recycled” and that the basic water‑cycle principles taught in third grade still apply.

The city council is expected to seek clarification from the city manager in the coming weeks and may consider revising future presentations to align more closely with the state‑filed water‑supply application.

Original reporting: Scottsdale Progress — read the source article.