Post-closure monitoring requirements for the Cactus Spring Waste Trenches (Corrective Action Unit [CAU] 426) (Figure 1) are described in Closure Report for Corrective Action Unit 426, Cactus Spring Waste Trenches, Tonopah Test Range. Nevada, report number DOE/NV--226, August 1998. The Closure Report (CR) was submitted to the Nevada Division of Environmental Protection (NDEP) on August 14, 1998. Permeability results of soils adjacent to the engineered cover and a request for closure of CAU 404 were transmitted to the NDEP on April 29, 1999. The CR (containing the Post-Closure Monitoring Plan) was approved by the NDEP on May 13, 1999. As stated in Section 5.0 of the NDEP-approved CRY Post-Closure Monitoring Plan, site monitoring at CAU 426 consists of the following: (1) Visual site inspections done twice a year to evaluate the condition of the cover and plant development. (2) Verification that the site is secure and condition of the fence and posted warning signs. (3) Notice of any subsidence, erosion, unauthorized excavation, etc., deficiencies that may compromise the integrity of the unit. (4) Remedy of any deficiencies within 90 days of discovery. (5) Preparation and submittal of an annual report. Site inspections were conducted on May 16, 2001, and November 6, 2001. All inspections were made after NDEP approval of the CR, and were conducted in accordance with the Post-Closure Monitoring Plan in the NDEP-approved CR. This report includes copies of the inspection checklists, photographs, recommendations, and conclusions. The Post-Closure Inspection Checklists are found in Attachment A, a copy of the field notes is found in Attachment B, and copies of the inspection photographs are found in Attachment C.
