1.2.1. Groundwater and Vapor Environmental Sampling Program: Vendor will execute the Groundwater and Vapor Environmental Sampling Program services and reporting, which includes conducting all monthly, quarterly, and biannual groundwater and/or vapor sampling as required by the state. Sampling frequencies will be described below and are subject to change based on plume behavior and at the discretion of WVDEP Office of Environmental Remediation (OER). Reporting for all sampling events will also be required as indicated below. This element also includes the installation of new monitoring wells as directed. 1.2.2. Remediation System Operation and Maintenance: Vendor will ensure that the remediation systems operate and are maintained as specified to successfully treat the plume as intended. An O&M manual, which outlines a procedure for proper orientation and maintenance of the treatment systems, is referenced below and attached. 1.2.3. Planned, Unplanned, and Emergency Remediation System Repairs and Replacements: Vendor will provide both scheduled and emergency repairs as needed, based on criticality of the needed repair. Both planned and emergency repairs will require the approval of WVDEP. Planned replacement parts will be addressed via state purchasing contracts in effect when the repair/replacement need is identified as indicated below. Unplanned replacement items will be approved by WVDEP and will be acquired directly by the Vendor as soon as practicable (see section 5.5.3).