The public has until May 7 to comment on the document, which must be certified by the City Council before the planned project can move forward.
Although other environmental impacts were found to be insignificant, or less than significant after mitigations are put in place, the intersections of Watkins, where the park is located, and the two main thoroughfares were flagged in the report.
According to the draft EIR, if the library is built in the park, the town must install a traffic signal at Middlefield and Watkins, which would solve the existing problem of delays at that intersection, and make the traffic flow tolerable even if the library is built nearby.
The current "level of service," or LOS, at that intersection is rated F. LOS ratings range from A to F, with F indicating the worst level of delays for vehicles navigating the intersection.
The draft EIR also identified a mitigation measure for the Watkins/El Camino Real intersection, but added that the measure is likely to be found infeasible: It requires a dedicated right-turn lane from Watkins onto northbound El Camino, but that would involve the taking of residential property in the right-of-way. As a result, the traffic impact at that intersection is "significant and unavoidable," the EIR says.
The town might be able to lessen the impact of additional traffic at the intersection by providing more police enforcement of a left-turn ban from Watkins onto southbound El Camino. The existing ban covers 4 to 6 p.m. Monday through Friday, but a number of drivers ignore the restriction, according to the EIR. Nevertheless, "the effectiveness of additional monitoring cannot be quantified, and therefore it is unknown whether the impact would be fully mitigated by the measure," the report says.
The LOS at the intersection is already rated F for peak morning traffic. For peak afternoon traffic, it is now rated D, but is expected to drop to E even without the library in the park. But if the library is built in the park, peak afternoon traffic is expected to cause delays at the intersection that will earn an F rating, the EIR says.
Parking demands would increase in the park to a significant level if the library is built there, the report says. But with mitigation, it would be a "less than significant" impact.
The mitigation measure listed in the report would require the town to count heads at events in the park's Pavilion, restricting attendance to 92 people for weekday events and 58 on weekends.
If an event is expected to draw more people, the town must see to it that there are no other special events during that time, and that the event doesn't take place during peak library hours, the EIR says.
Also, the event coordinator would be required to submit a trip-reduction plan to the town, which could include off-site parking and shuttling.
The report also studied alternatives to building the library in the park, including a project, supported by a number of residents, to renovate the library in its current location in the Town Center. It also looked at environmental impacts of a library at the proposed location, where the Main House now sits, but reduced to a maximum of 10,000 square feet; and of a library built instead on the North Meadow site in the park.
The draft EIR will be reviewed by the Planning Commission on April 25.
Go to http://tinyurl.com/brcvvh9 to read the document. It is also available to read at Town Hall, 91 Ashfield Road in the Town Center.
Comments on the draft EIR can be mailed to Lisa Costa Sanders, deputy town planner, at 91 Ashfield Road, Atherton, CA 94027. The public may also submit comments during the April 25 Planning Commission meeting.
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