PICNIC POINT — A developer won approval last week to move ahead with plans to build a 112-home subdivision near Picnic Point Elementary School, despite a neighborhood group’s objections over erosion, storm runoff and traffic.

The Frognal Estates project would transform the last large parcel of undeveloped land in the Mukilteo area. The rugged, wooded property covers 22 acres and lies about a half mile south of Mukilteo city limits.

Snohomish County hearing examiner Peter Camp issued a decision Wednesday denying an appeal that sought to stop or curtail the development.

Before breaking ground, Everett-based developer Integral Northwest must obtain permits and comply with conditions outlined in Camp’s 52-page decision.

The company’s CEO, John Lakhani, was unavailable for comment Friday.

The first plans for the development were submitted to the county under the name Horseman’s Trail in 2005, before the recession sunk the housing market. The county didn’t issue a final environmental impact statement until September of last year.

A neighborhood group called the Picnic Point Preservation Committee filed an appeal in October. Members reacted with frustration to the hearing examiner’s decision.

“Our community is extremely disappointed and shocked to have the county dismiss the impacts and the property rights of current home owners, as well as impose the future cost and risk to the community, county and environment,” said Emily Mydynski, the committee’s president.

Mydynski said she was hoping for a different outcome after hundreds of people demonstrated “significant, legal and professionally supported concerns” with the project.

The group was weighing its options for an appeal of the decision.

Building out Frognal Estates, named after an upscale London neighborhood, will require moving an estimated 285,000 cubic yards of dirt. That would help even out some of the hilly terrain. Plans also call for an intricate drainage system and large retaining walls to buttress slopes.

Camp’s decision was based on testimony between Feb. 29 and April 1. He heard from scientific experts and more than 40 opponents. He also visited the site four times.

The decision sought to probe an array of issues. Among them: traffic, drainage, landslide risks, wildlife habitat and the potential for damage to Picnic Point Creek, which runs 500 feet from the property line.

He concluded that the area poses little danger for landslides, as the geology there differs from the Puget Sound coastal bluffs and has not experienced any slides for hundreds of years.

The developer must monitor for any signs of muddy water flowing off the property.

The examiner ordered that construction traffic use Picnic Point Road to the extent possible and to avoid 60th Avenue West, which runs by the elementary school.

Noah Haglund: 425-339-3465; nhaglund@heraldnet.com. Twitter: @NWhaglund.