2005/02/23 Council Agenda Packet

7 Project: Everett Landfill&Tire Fire Site Perimeter Landfill Gas Collection and Disposal System Change Order no. 1 Change Order Effective Date: February 10,2005 Exhibit A—Description of Changed Work See attached January 18,2005 letter to Glacier Construction Services for a description of the work. The work described in the January 18,2005 letter is requested by the City for the following reasons: The landfill gas collection work at the Everett Landfill is being done as required under the April 2,2001 Consent Order with the Department of Ecology. Site investigations determined that landfill gas was migrating beyond the landfill boundary at levels that exceeded Ecology regulations. Landfill gas migration problems are dependent on subsurface conditions that can significantly vary within a site(e.g.soil types, amount of garbage,gas pressure,age of garbage,ground water levels,etc),and can lead to difficult control situations. The installed gas system reduced the gas levels along the landfill perimeter at those locations where high gas levels exist(west and north boundaries). However,at two locations gas levels were not reduced enough to bring the landfill site into compliance with Ecology regulations. Therefore additional measures need to be constructed to bring the landfill into regulatory compliance. This proposed change order provides for construction of the added collection system to capture the migrating landfill gas. This added collection is within the original construction area,uses the same construction details and plans,and provides for the most cost efficient means to complete the landfill gas collection system. 21 Exhibit A