Mona council hears stark warnings that secondary irrigation system is at capacity and studies costly fixes
Get AI-powered insights, summaries, and transcripts
Subscribe
Summary
Councilors were told Mona’s secondary irrigation network was designed for the town’s original footprint and is now nearing capacity; staff outlined options ranging from small pump-and-treatment work to a full $26.6 million overlay, and highlighted a sewer‑reuse permit for 388 acre‑feet that would require significant capital and O&M costs to use locally.
Councilors at a Mona work session on water were warned the city’s secondary irrigation system — built in the late 1990s for the town’s original ~640‑acre footprint — is effectively at capacity and cannot absorb unlimited new taps.
Gordon, a staff speaker who provided the technical overview, said the irrigation company originally delineated shares as “town” or “field,” and the secondary system sizing, storage and pipe capacities were based on that original footprint. "The system itself is only so big and it is way over taxed," another council speaker said, noting the system "won't handle more" without substantial upgrades.
Councilors discussed practical implications: some town shares are currently routed through field ditches to serve parks and small agricultural parcels, and converting additional field shares into the system risks immediate overcapacity. Staff cautioned that putting additional shares into the system would quickly tax pipeline capacity and create pressure to drill more wells or expand the culinary system.
Options reviewed included accepting pond systems managed by homeowners associations (HOAs) to store water, extending the culinary system to serve irrigation areas, acquiring a local well (Barnswell) and retrofitting it as a backup, or using treated sewer effluent. Speakers repeatedly raised liability and operational concerns for pond/HOA approaches, noting HOAs must guarantee maintenance or the city could face complaints when on‑site secondary water fails.
Staff said the city holds a water reuse permit authorizing 388 acre‑feet of reclaimed water but using that supply locally would require a pump station and chlorination/treatment to convey it into irrigation or culinary systems; the low‑cost estimate for that pump/treatment option was discussed as roughly $1.2 million and still carries ongoing O&M costs. By contrast, Sunrise Engineering’s report included a full upper‑zone system replacement or overlay estimated at about $26.6 million.
Speakers emphasized seasonal limits as well: the reuse plant’s output (discussed as roughly 200,000 gallons per day) would likely exceed irrigation demand only part of the year, creating the need for winter storage if the city invests in pumping and conveyance infrastructure. Council members asked staff for more detailed cost/benefit studies, feasibility modeling and an assessment of who would pay construction and ongoing costs before pursuing any capital option.
The session ended with staff and council agreeing to examine engineering models and funding options further, including the Barnswell well retrofit as a potentially lower‑cost backup to consider alongside reuse and pond scenarios.