Bend committee reviews $22 million draft stormwater master plan, prioritizes UIC retrofits and service-level work

At its May Watershed Advisory Group (WAG) meeting, city staff and their consultants presented draft recommendations from an update to Bend's stormwater master plan, outlining a capital-improvement program of about $22 million, prioritization of underground injection controls (UICs) for retrofit or removal, and a plan to develop service-level standards that could feed a future rate study.

The draft plan matters because it targets projects and program changes intended to protect the Deschutes River and local groundwater, reduce recurring localized flooding and repair aging stormwater infrastructure. City staff told the advisory group the work will inform a fall city council adoption and the timing and scale of any future funding requests.

Trista Koblowski, project manager for the stormwater master plan update at OTAC, said the update focuses on both drainage and water quality. "This is probably our last meeting where we're going to talk about the stormwater master plan," she told the WAG as staff summarized the recommended capital program and next steps.

The plan update produced three linked outputs the group reviewed: (1) a prioritized capital-improvement program (CIP) with 13 draft project fact sheets, (2) a set of UIC siting and retrofit priorities, and (3) proposed level-of-service options for operations and maintenance that will inform future rate work. Laurie (identified only as City of Bend staff during the meeting) and staff said a draft of the full plan would be available for review in late June or early July and staff hope to present a final plan to council in September.

UIC inventory and priorities

The consultants reported that Bend's stormwater inventory includes roughly 7,000 UICs. They distinguished between conventional dry wells and deeper, "modified" or "deep" dry wells that can reach 100 feet or more and may bypass low-permeability layers. The team mapped streets and rights-of-way where siting modified deep wells would be lower risk (shown in green on the draft map) and other areas that would need stronger engineering justification (shown in yellow).

A hydrogeology review identified about 1,000 older drill-hole UICs that lack modern groundwater protections. From that group, the consultant team flagged 17 drill holes (shown in red on the draft map) as the highest risk because of proximity to municipal water wells; staff recommended those be prioritized for retrofit or decommissioning over the next five to 10 years. Separately, staff identified about 18 failing UICs (dry wells or drill holes that have silted in or are undersized) that produce recurring nuisance flooding; those locations were grouped into a capital-maintenance program and may be handled through repair-and-replacement budgets or as distinct capital projects.

Capital projects, scoring and costs

Consultants said they identified roughly 100 known drainage and water-quality issues in the city and screened them to produce 13 prioritized CIP project fact sheets. Projects were scored using four categories (conveyance/flooding, water quality, multiple benefits, other priorities) plus feasibility and cost; the scoring system yields a maximum of 80 points. The top-ranked project scored 51 points.

Fact sheets pair concept drawings with estimated unit costs. As an example, the team used a planning-level unit cost of about $75,000 per deep dry well (all-inclusive of drilling, backfill and pavement restoration) to generate project cost estimates. Some retrofit projects that treat large drainage areas are considerably more expensive than simple drainage fixes; the draft shows the Galveston/Northwest Riverfront outfall retrofit—covering roughly 16 city blocks—as the most expensive single project because it would likely require multiple proprietary underground filtration vaults and additional conveyance work. The draft CIP cost in today's dollars totals about $22 million and is intended as a 10–20-year program; staff cautioned the number will change as project fact sheets and city comments are finalized.

Operations, maintenance and level of service

A second major theme of the meeting was level-of-service (LOS) choices for stormwater operations and maintenance. WAG members were asked for input on whether current service levels meet expectations and on individual program areas such as street sweeping, nuisance flooding response, erosion control and public education. Laurie described LOS as linking "what services we provide" to frequency and funding, and noted gaps in the city's asset-inspection program (for example, limited closed-circuit-television inspection of storm pipes).

Staff described current revenue structure: Bend's stormwater utility relies on monthly rates (charged by equivalent residential unit) and does not use stormwater systems-development charges. Staff stated an approximate residential stormwater charge of $7.50 per month, which they described as low relative to other utilities, and noted the program currently pays roughly 40% of street-sweeping costs with the transportation program covering the remainder.

Maintenance needs tied to treatment technologies received particular attention. Consultants said underground proprietary filtration vaults commonly use replaceable filter cartridges that can require annual replacement; that routine maintenance may either be done in-house or contracted out and will carry ongoing budget and staffing implications. "The cartridges need to be changed out often," the consultant team said while noting life-cycle estimates for vault structures themselves are typically multi-decade.

Next steps and outreach

Staff and consultants outlined immediate next steps: publish the draft plan for public review in late June or early July, finalize based on feedback, and seek city council adoption in September. The team plans an in-person field tour on June 4 at Overturf Park (West Side) to review waterwise and Firewise tradeoffs on a site that is both a park and an important elevated water site. Staff also said they are drafting updates to stormwater standards to incorporate deep-dry-well guidance this calendar year and will publish an interactive GIS version of the CIP on the city's utility viewer so project status can be tracked over time.

What WAG members said

Members asked about expected maintenance and lifetimes of proprietary systems, the feasibility of underground treatment in very flat areas, and how park and recreation activities affect river sediment and water quality. Mark Buckley, representing the ECC environment and climate committee and speaking as an economist, noted it can be hard to sustain public attention on stormwater because so much of the work is out of sight; he urged framing LOS choices around visible problems such as recurring flooding. Trista Koblowski encouraged members to review the draft when available and to supply written feedback.

The draft plan will be posted to the city website for review; staff said they will follow with more detailed LOS-to-cost analysis and a rate study conversation after plan adoption. The WAG resumes in September after a summer break; staff said some focused meetings or follow-ups may occur as needed.