Bathymetric survey finds mixed pond needs; council to approach HOAs about cost-sharing and possible city-funded cleanup

Allison (city staff) presented the results of bathymetric surveys conducted by WSB for selected stormwater ponds. The survey used the city's surface-water-management asset program to prioritize ponds with anticipated sediment loading.

Some ponds were found to be performing as designed. For others the consultant recommended excavation: a Hunters Crest pond was recommended for an average 4.7-foot excavation (estimated at about $16,400) and a Jennings Cove pond was estimated at about $20,800 for a 2.5-foot average excavation. Allison warned cost variation depends on pond area, accessibility and how contractors stage work.

Council discussed tools to pay for remediation. Allison and the city attorney identified options including using the stormwater fund, pursuing special assessments where a clear benefit can be shown (Chapter 4.29 was raised), or negotiating agreements with HOAs that would accept future maintenance responsibility if the city performs a one-time cleanup now.

Councilors expressed concern about equity and scale (private ponds without agreements could create a large aggregate liability), and asked staff to return with outreach to HOAs showing estimated costs and proposed agreements. One councilor suggested a 50/50 cost-sharing model similar to road-improvement assessments; staff said benefit analyses and engineering valuation work may be needed to support assessments.

There was no decision to undertake large-scale remediation at this meeting; staff will pursue HOA outreach, identify the number of private ponds without agreements and return with options and costs.