725-6MW-1214-Monitoring Well Project

725-6MW-1214-Monitoring Well Project

Caltrans approves the encroachment permit for Rosecrans Partners LLC, seeking access to one (1) groundwater monitoring well located within Caltrans right-of-way. The well (OB-21D) is located between Ayres Hotel (14400 Hindry Ave., Hawthorne, CA 90250) and the southbound Route 405 off-ramp at Hindry Ave. at postmile (PM) 19.21, in the City of Manhattan Beach, County of Los Angeles. The well sampling activities will be conducted quarterly by Blaine Tech Services (contractor) and supervised by Bowyer Environmental Consulting, Inc. (BEC). BEC will ensure that only decontaminated or new monitoring and sampling equipment is utilized during quarterly sampling events. All groundwater purged from the well is collected in containers and removed from the site. It is estimated that approximately seven (7) quarterly sampling rounds will be conducted over the requested access period. BEC acknowledges that the OB-21D well will be abandoned following quarterly groundwater monitoring, in accordance with applicable regulatory requirements. A licensed (C-57 Contractor) driller shall over-drill the existing well to total depth using a 10-inch outside diameter hollow-stem auger to remove the well casing, filter pack, and annular seal. Once drilling is complete, the borehole will be backfilled with a bentonite/cement slurry from the bottom up to 0.5 feet below ground surface, using an auger or a PVC tremie pipe, per California Well Standard. The upper 0.5 foot will be completed with asphalt or cement to match the existing surface. There will be no other excavation. No public utilities will be relocated, and no new right-of-way will be acquired for the project.

Manhattan Beach

Los Angeles

Southern California