YarrowBay has presented new information concerning phosphorous runoff to Lake Sawyer from two master planned developments in Black Diamond.
The Kirkland-based developer has informed the city there will be “no net increase” of phosphorous runoff into the lake from the two developments it is planning in Black Diamond, The Villages and Lawson Hills.
The potential for increased levels of phosphorous in the lake was a controversial and contentious issue during the 2010 public hearings on the developments. The hearings included SEPA (state environmental protection act) appeals presided over by the city’s hearing examiner and a MPD application consideration before the City Council.
Phil Olbrechts, the city’s hearing examiner, wrote in his executive summary of the SEPA appeal, “Determining the adequacy of the Lake Sawyer water quality analysis was by far the most difficult decision to make on the SEPA EIS (environmental impact statement) appeals.”
Increases in phosphorus levels can contribute to blue-green algae blooms, which can create health problems in fish and humans.
Al Fure, a consultant with Triad Associates in Kirkland, stated samples were collected during a rainstorm in December that provided more accurate data than what was available during the hearings. The samples were used to measure the phosphorus levels currently coming off the project sites.
Fure noted the measurements allowed Triad to determine if it is feasible to control phosphorus to predevelopment levels.
According to a release from YarrowBay, the “no-net increase” of phosphorus exceeds the standard set by the Lake Sawyer Management Plan and the requirements of the Department of Ecology’s 2005 Stormwater Management Manual the city has adopted.
Fure wrote in an e-mail the Lawson Hills site was selected as the initial testing area because it is the “largest of the projects tributary to Lake Sawyer and would therefore have the largest potential impact.”
Fure said Triad tracked a rainstorm in December to decide when to send the technician into the field to collect the samples. The collection was made on a Sunday.
“You can’t plan on when storms will occur (during the week) in Western Washington,” Fure said. “We collected water samples from three different points on the Lawson site.”
Once collected the samples were sent to a Seattle lab for analysis.
“All along we have had a passion for the lake, but without hard data we couldn’t confirm where we stood,” Fure said
After consulting with Harry Gibbons in the Seattle office of the California-based firm, Tetra Tech, Fure said Triad and YarrowBay are confident the goal of no increase in phosphorus levels in the lake from the developments can be reached.
Fure said the low impact development measures, using phosphorous-free fertilizers in public areas and storm water quality treatment practices will also help control phosphorus runoff.
The city’s Community Development Director Steve Pilcher said the staff is still reviewing the information submitted by YarrowBay, but noted, “their commitment to no more phosphorus is very positive. This is beyond what the conditions of approval required.”
The City Council approved the two projects in September. YarrowBay submitted development agreement applications, which will go before the hearing examiner in a public hearing. The hearing examiner will provide a written recommendation on the development agreement to the City Council.
The group Toward Responsible Development filed a land use petition act or LUPA appeal against the two developments that is in state and federal court and with the state Central Growth Management Hearings Board.
