By Richard Van Winkle, News of Mill Creek.
The City of Mill Creek owns and is responsible for maintaining a stormwater system comprised of catch basins, underground pipes, retention ponds, and water treatment facilities.
The city’s stormwater system conveys rain water from rooftops, driveways, sidewalks, roads and other impervious surfaces to water treatment facilities such as retention ponds before eventually ending up in local creeks, streams, and wetlands.
When stormwater pipes fail and develop leaks, rain water disperses into the ground and carries away surrounding soil as it does. This results in voids, which in many cases cause sinkholes.
Realizing that the Mill Creek stormwater system is aging and that failures can result in sinkholes like the one at Sweetwater Ranch in December 2017, the city council approved a $130,000 consulting engineering contract with Perteet Engineering in February to help develop a capital projects plan.
At the September 11, 2018, Mill Creek City Council meeting Public Works and Development Services Director Gina Hortillosa gave an update on this effort.
The good news is that the preliminary stormwater system analysis was pretty much completed on time and the contract is under budget by $26,000 at this point.
The bad news is that the analysis shows $750,000 to $1,000,000 of stormwater system repairs need to be made in 2019, with an additional $600,000 to $800,00 to be spent each year beginning in 2020. This totals out to over $5,000,000 worth of planned repairs by 2027.
The analysis only looked at stormwater pipes larger than 18 inches in diameter, because their failure has the potential of causing the most damage.
The large stormwater pipes represent about 15% of Mill Creek’s stormwater system and there are known smaller pipe failures that were not included in the cost estimates that will have to be repaired as well.
Perteet Engineering consultant Dave Smith told the city council that the analysis identified quite a few serious failures in the city’s large stormwater pipes.
He said the recent Sweetwater Ranch sinkhole was caused by an undetected large stormwater pipe failure. It cost the city about $900,000 and took months to fix this problem.
Smith told the city council that fixing the Sweetwater Ranch stormwater pipe would have cost about $600,000 less if the failure had been detected earlier.
Hortillosa told the city council that the repair estimates don’t include upfront design costs and inspection costs during construction. She said these costs could add 25% to the repair estimates.
Washington State laws require all of Mill Creek’s surface water projects to be paid by special fees assessed to property owners. These projects include consulting engineering contracts, catch basin cleaning, pipe repairs, and anything else pertaining to the city’s stormwater system.
Unlike some other Puget Sound cities that assess surface water fees to property owners monthly, Mill Creek property owners pay $78 yearly. This fee hasn’t changed since about 1998 and is included in the property tax collected by Snohomish County.
Unfortunately, the $750,000 in total surface water fees collected by the city each year isn’t enough to pay for the stormwater system repairs that have to be made as well as the costs of ongoing system maintenance.
Interim City Manager Bob Stowe told the city council he will hire a consultant to help figure out how much the surface water fee will have to increase. He told the city council this will cost about $45,000.
The city council plans to hold a couple public hearings beginning on November 6th to discuss the budget for the next two years as well as the property tax rates and the increased surface water fee.
The city would like to hear from Mill Creek residents regarding these issues.
You can submit comments on the City of Mill Creek website at www.cityofmillcreek.com/responsecenter.
Click on “Create a Service Request” and then “Public Works & Development Services” to find the type of comment you want to make.
You will have to create an account on the website in order to submit your comments.