Stormwater woes drive up costs in Manchester

Kitsap County Surface and Stormwater Management is poised to spend another $800,000 to $1 million to try and solve Manchester’s on-going drainage problems.

The latest project comes a little less than a year after SSWM paid to enlarge and upgrade the Alaska Avenue stormwater detention pond at the south end of Manchester. Both plans are part of a preliminary report done in 1999 to assess Manchester’s stormwater problems and propose possible solutions.

“We just had a lot of complaints and requests for action,” said SSWM project engineer Michael McCarthy.

McCarthy said the Manchester area has chronic water-related problems. Residents are constantly reporting overflowing drainage ditches, undersized culverts and water polling in residential backyards. The current project, now in its planning stages, would address the Main Street outfall and the collection systems that feed into it.

Much of downtown Manchester is served by the Main Street system. The main collector runs from the Manchester dock up Main to Madrone Avenue, then south on Alaska Avenue to Collins Road. Past Collins, the stormwater is diverted into the Alaska Avenue system.

“It has to do with the lay of the land — how things slope,” McCarthy said.

Right now, all the runoff from that entire area drains into Puget Sound at Main Street via a 24-inch pipe. That pipe, said McCarthy, is much too small to handle the volume of water coming out of Manchester, particularly during heavy storms. The pipe also drains above the mean low tide mark, creating an erosion problem.

SSWM engineers originally hoped to simply enlarge the pipe and extend further out into the water. However, eelgrass — a critical salmon habitat – was found just beyond the outfall site and made the so-called plan “A” unfeasible. Eelgrass beds are protected habitat under state law and therefore present a major obstacle to construction nearby.

“Permitting something in that area would be really really difficult and you’re better off going somewhere else,” McCarthy said.

SSWM therefore hired a Tacoma-based engineering firm to create an options list of four different potential locations along the Manchester waterfront, combined with three different possible locations for the end of the pipe to fall — at or above the mean high tide mark, below the mean low tide mark, or somewhere in between.

Of those 12 possibilities, four finalists were chosen. All four will be on display Monday night at a project open house at the Manchester Library.

*Option D1 is located off the south leg of Daniels Loop and falls above the mean high tide mark.

McCarthy said the location is a good choice because, with the pipe mouth above the tideline, crews wouldn’t have to work on the beach as much, digging and laying the pipe. However, SSWM would have to lay riprap — large chunks of rock — around the pipe mouth to reduce erosion. This, said McCarthy, could create fish habitat issues. Even with the riprap, McCarthy said there would still be some beach erosion and SSWM could have permitting problems as a result.

The estimated cost of the option is $861,000.

*Option C2 is located north of the Manchester boat ramp in the intertidal zone.

“The exact endpoint would be worked out in the final design,” McCarthy said.

The option works better than the current site to the south because there are no eelgrass beds there and boat traffic is less. With the outflow between the high and low tide lines, McCarthy said erosion would be less than at the Daniels Loop site, although SSWM might still have to lay some riprap. McCarthy said there will definitely be permitting issues since significant excavation will have to be done to lay the pipe.

Crews would also have to rip up the Port of Manchester’s parking lot to run the new pipe from Main Street to the outflow site. McCarthy said the port has been very cooperative with SSWM’s plans, but said the agency would rather not cut a trench through a parking lot if it didn’t have to.

The estimated cost of the option is $820,000.

*Option B3 runs between the boat ramp and the nearby dock, ending at the mean low tide mark.

McCarthy said this choice would eliminate the need to dig up the parking lot and would keep the discharge submerged nearly all the time, reducing erosion. The project would require much pricier construction equipment, since half the digging would be done partially underwater. The area is also high-traffic, resulting in possible complications with passing boats.

The estimated cost of the option is $914,000.

*Option B4 runs at the same site as option B3, but the outfall is underwater at all times.

McCarthy said this is very likely a highly impractical option, but said it was necessary to show all possible choices.

“We felt we needed to include one of these deep-water outfalls in the study because someone will ask us: ‘Did you look at this?’ So we did,” he explained.

The benefits are pretty clear-cut, McCarthy said — the deep-water option has none of the erosion or boat traffic issues associated with other options. However, that convenience comes at a cost. McCarthy said the project would require an aquatic easement from the Department of Natural Resources. He said he didn’t know what the price tag would be, but said the process would be “time consuming and costly.”

“We haven’t had to get one from DNR yet, so we don’t have the experience,” McCarthy said. “And it’s a moving target.”

The estimated cost of the option is $1,045,000 — not including the DNR easement.

A few Manchester residents have already seen the project. SSWM officials presented the options at a Port of Manchester meeting, at which time the board unanimously approved a resolution backing option C2. Port Commissioner Bob Parks said even though that option requires cutting into the port’s main parking lot, it seemed to the commissioners to be the only viable choice.

“That’s the only logical place for it to go,” Parks said.

Despite the resolution, however, it appears public opinion is largely against the project as a whole.

Parks, who lives at the corner of Beach Drive and Daniels Loop, said is property is constantly flooded out by excess runoff. The property below his, he said, is essentially unsalable because of the stormwater problem. Nevertheless, he doesn’t see the proposed upgrade as the answer to his problems.

“When they built the roads out here, they tilted them the wrong way,” Parks explained. “They’re spending a lot of money and aren’t going to accomplish a lot.”

Manchester resident Jim Thompson, who also serves as a port commissioner, said he wasn’t thrilled with the last project SSWM did in the area — the Alaska retention pond.

Thompson said his neighborhood — the Alaska Avenue area — doesn’t have any flooding problems and hasn’t had any problems in the last 20-odd years. He sees the upgrade projects as largely useless or, in the case of the retention pond, a source of aggravation.

“I think it’s stupid and a place to breed mosquitoes,” Thompson said. “I think (the project) is one heck of a waste of money.”

The money for this project will come out of SSWM fees, which are included in county property taxes. McCarthy said single-family home owners pay about $45 into the SSWM fund; commercial properties are assessed base on their total impervious surface area. The money pays for capital projects like the Manchester upgrade, but also pays for repairs and maintenance on existing stormwater systems.

Because SSWM works on several of these projects at once, McCarthy said the process from identifying the problem to fixing it is usually a slow one. With luck, McCarthy hopes to award a design contract for the project this fall, after a preferred option is chosen. Permit applications will likely go out the following summer and then, McCarthy said, it’s pretty much up to the Army Corps of Engineers and the other permitting agencies how long SSWM has to wait to start construction.

“Supposedly the Corps’ getting better, but it could take one to two years to get a permit,” he said.

In an effort to spread out the cost and the work, SSWM plans to upgrade the system in phases, starting with the outflow pipe. Crews will eventually work all the way up Main Street and Madrone, but McCarthy could not even begin to guess at a projected completion date for the whole project.

“We haven’t broken down how big of bites this will be,” he said.

There are still several projects left in the 1999 Manchester report. According to the study, Virginia Avenue East is impassable during large storms because of flooding. Ricky Court, also on SSWM’s to-do list, suffers from intermittent flooding and the potential for septic tank submersion.

Nevertheless, McCarthy doesn’t expect to get around to those project areas for quite some time to come.

“I think we’re going to be concentrating for some time handling the phases of this (project),” he said.

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