Aurora water officials propose shrinking planning boundary, warn of multi‑billion dollar supply gap

Aurora City water officials on Wednesday told the Water Policy Committee that accelerating demand and shrinking water supplies leave the city facing a large future shortfall unless planners trim the area they expect to serve and press ahead with costly supply projects.

The presentation, billed “Growth with Intention,” summarized the Integrated Water Master Plan (IWMP). Staff said the IWMP projects population growth of roughly 40% over 20 years and estimates a future need of roughly 23,000–25,000 acre‑feet over 35 years driven by growth and system losses.

Why it matters: staff said rising evaporation and stream losses tied to warming are reducing usable supplies even where precipitation is unchanged, and regional competition for remaining supplies makes new large projects more expensive and uncertain.

Staff described current and future supplies in the city’s planning models: current treated withdrawals are shown near 93,000 acre‑feet (which includes system losses and contractual commitments), distribution volumes are closer to 55,000–60,000 acre‑feet, and Prairie Waters and other planned projects are shown as partial offsets. Officials said stream losses have climbed (from roughly 10% in 2012 to nearly 20% in recent years), amplifying the effect of any supply reductions.

The presentation laid out supply options and constraints: - Mountain supplies (Upper South Platte and Colorado River basin) are effectively tapped out; the Eagle River project was described as “a 100 times harder” than the Wildhorse proposal and not relied upon. - The city has roughly 10,000 acre‑feet available from Arkansas Basin farm purchases, with about 7,500 acre‑feet reliable in 3 of 10 years under current agreements. - “Portfolio E,” an aspirational combination of Lower South Platte acquisitions and infrastructure, would require roughly $680 million in water acquisition capital and total capital in a range staff presented as approximately $1 billion to $2.7 billion to implement by 2055, depending on what outcomes are achieved.

Staff proposals and next steps: staff said they will recommend a phased policy package to council including: no new extraterritorial service agreements; no emergency connections outside city limits; trimming the current planning‑area boundary by roughly half (about 20 square miles removed from the current planning area); and a future second phase that could include tighter policies on water use within annexed areas. Staff said the trimming is intended to reduce future obligations and focus the city’s capital and acquisition plans on areas it realistically can serve.

Officials stressed that trimming the planning area is not a land‑use seizure and that property rights and existing commitments must be respected. Staff said additional analysis will be needed before any changes are finalized and that they will return with concrete recommendations for council review.

On conservation and landscaping, staff discussed possible policy tightening for turf and public parks (including stronger limits on “nonfunctional” turf and incentives or requirements for lower‑water turf or artificial turf for high‑use sports fields). They also noted maintenance tradeoffs: low‑water landscaping can reduce irrigation but requires different weed control and outreach to residents and property managers.

What’s next: staff said they will present a formal recommendation to council after additional analysis; they described the work as phase 1 of a multi‑stage process that could include further reductions to the planning boundary and additional policies on annexations and landscape standards.

Ending: committee members asked for follow‑up on which portions of the green (annexed future growth areas) might be candidates for non‑irrigated uses and on how trimmed areas would be identified. Staff said they would return with more detailed maps and recommendations.