Impacts of homes on fish avoidable, county says


Under legal pressure from the Salmon Protection and Watershed Network, Marin County released a draft supplemental environmental impact report last Monday that analyzes the impacts of future potential development on the San Geronimo Valley watershed. 

The county had stalled for almost three years on a court order to complete the report, meanwhile relying on an outdated 1994 Countywide Plan to assess the impact of all new and expanded development in the area. 

Though it uncovered evidence that development was cumulatively disturbing the reproductive capacity of trout and salmon, the report also claimed that no effects were significant enough that they could not be ameliorated by mitigation efforts. 

In addition to the report’s more urgently recommended mitigation measures, the county has also volunteered to take further action to reduce impacts. 

A 45-day period for the public to submit comments on the supplemental draft environmental impact report began on May 1. 

“SPAWN will review the S.E.I.R. in detail and participate in the public comment process mandated by CEQA on all issues of concern, including impacts to protected species of salmon and their habitat,” said Andrew Ogden, an attorney for SPAWN, which has sued the county repeatedly over the last decade over regulations meant to protect coho salmon and steelhead trout in San Geronimo Valley streams. “Our ultimate goal is and has always been to have the county develop and enact a comprehensive stream conservation area ordinance to fulfill [its] obligation to protect the salmon and their habitat.” 

According to a county press release, the draft S.E.I.R. “found that there would be no significant and unavoidable adverse cumulative impacts on salmonids” from homes and other development under the current 2007 Marin Countywide Plan. That plan guides land use and development and seeks to minimize biological and wetland resource impacts. 

“We’re pleased that the cumulative impact analysis did not conclude that there will be significant, unavoidable, and unmitigable impacts on salmonids as a result of the 2007 Countywide Plan,” Tom Lai, assistant director of the Community Development Agency, said in the press release. 

Yet the analysis in the S.E.I.R.—conducted for the county by Stillwater Sciences—also found that the effects of the 2007 Countywide Plan on threatened and endangered salmonids will only be reduced to a “less-than-significant-level” if the county takes some mitigation measures. These measures, the report says, “are required to avoid, minimize, or compensate” for potentially significant impacts of development and will help improve conditions for salmonids in the watershed. 

According to the report, the effects of urbanization—specifically of increased concrete and other impervious surfaces—will cumulatively increase storm flow magnitude and frequency. As a result, those changes will compromise the ability of rearing coho salmon to find adequate refuge during high flows. 

The report also showed reduced salmonid spawning success due to increased inputs of development-related fine sediment to stream channels. 

In response to those findings, the report proposed expanding and strengthening a stream conservation area ordinance that regulates development, controlling and reducing production and delivery of fine sediment to streams, and a number of winter habitat enhancement projects. 

A third impact was determined to be minor enough not to require mitigation: reduced salmonid summer rearing success due to degraded habitat conditions, including reduced habitat complexity, reduced streamflow and increased water temperature. 

While not required, the county elected to pursue a number of voluntary mitigation measures to address this, according to the report. Those measures include a groundwater study to determine how development might adversely impact the summer base flow in San Geronimo Creek as well as additional stream enhancement projects specific to the summertime.

Adequate cumulative impacts reporting as well as mitigation strategies were the two holes that SPAWN identified in the county’s 2007 environmental impact report for the Countywide Plan. 

Back in 2014, a San Francisco appeals court lifted an injunction against development in the valley that SPAWN had won in 2012. Yet the appeals court sided with SPAWN in concluding that the 2007 Countywide Plan lacked important aspects in its environmental impact report, and the judge mandated that the county prepare a supplemental report. Because those inadequacies had been identified, the county had to apply its 1994 plan in the interim when analyzing development projects in the valley. 

The county has put forward a number of reasons for the long delay in completing the draft. At a hearing in February, the county reported that the slowdown was arising with Stillwater Sciences. Marin Superior Court County Judge Paul Haakenson arranged another hearing 30 days later, and this time, the county’s attorney reported that the document was undergoing an internal review. 

But the county finally met its next deadline at a hearing on Monday, leading Judge Haakenson to raise his eyebrows as he remarked that it had been met “just under the wire.”

A public hearing by the county planning commission is scheduled for May 22 to receive comments on the draft S.E.I.R. from the public. Following the comment period, the Community Development Agency will prepare a final S.E.I.R. to submit to the Board of Supervisors for certification—closing the books on the approval of the 2007 Countywide Plan update. Judge Haakenson scheduled a status conference for Aug. 10 to monitor the county’s progress. 

County Counsel Brian Washington said that once the environmental report is approved—likely late summer or early fall, depending on the public review process—the county “will turn to mitigation immediately.”  


The 2007 Marin Countywide Plan draft Supplemental E.I.R. can be found at