Despite King County’s efforts to reduce impacts to trees and landscaping along the southern segment of the East Lake Sammamish Trail project, Sammamish officials say there’s more work to do.

The county released its 95 percent design plan in April as a good-faith effort to resolve some ongoing issues Sammamish residents have raised regarding the plan to widen and pave the trail.

The updated plans show 40 more trees will be spared, bringing the total number of trees to be removed down to 29, but the yet-to-be resolved issues still include trail width flexibility and a storm water detention vault.

“One item that just jumped out at me was the storm water vault location,” said Sammamish Public Works Director Laura Philpot during an update at the May 18 Sammamish City Council Committee of the Whole Meeting.

She said the length of its west wall and its height raised some red flags.

The vault was originally on the east side of the trail but was moved due to it’s impact to East Lake Sammamish Parkway. In its new location, the westward wall, called wall No. 5 in the plans, would act as a screen, 13 feet tall in some places, separating the trail and the residential neighborhood.

“(The county is) still trying desperately to not have to build the vault,” Philpot said. “The only way to not have to detention is if they could have a public drainage way all the way to the lake.”

These large walls were something residents had complained about during the construction to the northern segment of the trail, Philpot said. The northern segment is slated to open in June.

The city had also requested some flexibility with the trail width. The city asked the county shave off some of the 3-foot buffer planned for either side of the eventual 12-foot-wide trail.

“They’ve stated pretty affirmatively that they don’t intend to narrow the trail through this section,” Philpot said. “They didn’t feel that the impacts were great enough to warrant that modification.”

Tree removal was probably the most concerning portion of the county’s plan and will be something the city continues to monitor, even after the county committed to retaining about a mile’s worth of trees.

Other concerns that were addressed in the updated plan include the county’s stringent sight distance criteria and adverse impacts to critical areas.

“They were using very onerous and risk adverse standards that far exceed what the city has used,” Philpot said of the county’s sight distance criteria.

The criteria the county had been using required more landscaping be removed. While all plants will not be saved, more will be retained using the city’s standards.

To determine how much vegetation to remove, the county had been measuring 14.5 feet right and left from the stop bar, whereas city uses a 10-foot measurement. The county had also assumed a traveling speed of 20 mph, while the actual speed limit on the trail is 15 mph. Bikers also sit lower, by about 7 feet, than drivers, Philpot said, which factors into the appropriate distance.

“They all seem (like) very small changes but they do make a difference on the ground,” Philpot said.

The county is also making efforts to move the trail farther eastward in order to minimize impacts on trees and other mature landscaping.

Previously, the county had avoided the eastward side of the trail, as it had mostly been designated as wetlands.

City staff are encouraging the county to take advantage of the wetland buffers.

While the city is pushing the county to use the wetland buffer, Sammamish staff are also stressing the importance of maintaining the wetlands to help keep phosphorus levels low.

Councilmember Nancy Whitten has repeatedly taken issue with how the county will mitigate for phosphorus discharge into the lake.

According to Sammamish codes, the trail, classified as a non-motorized facility, is exempt from water quality treatment — meaning the county does not have to mitigate for phosphorus.

Even still, Philpot said the county has committed to reduce levels by also using native plants and non-phosphoric fertilizers.

Despite the issues city officials and residents might have with the plans, Philpot said the designs meet city code.

City and county staff will continue reviewing the plans. Once complete, the city will review the county’s permit request and will either approve or deny it.

Philpot does not know when the permit will be ready to submit.