CalRecycle Rotelli Burn Dump Remediation Project

The proposed Project is located near Mill Villa Court adjacent to State Route 49 (SR-49), southwest of the City of Sonora (City) in unincorporated Tuolumne County. The Project Area is defined as the areas that would be disturbed by remediation activities or used for access. The Project Area is located predominately within 2 parcels owned by different entities, Assessor’s Parcel Numbers (APNs) 056-020-004 (Rotelli), and 056-020-027 (Smith), with a small part of the drainage crossing through the lower corner of APN 059-010-034 (Bureau of Land Management). Remediation access would further cross portions of APN 056-020-029 (Hattler) and Caltrans right-of-way on the west side of SR-49. The Project would remove surficial waste (if found to be present at the time of remediation) and excavate waste materials from 2 burn dump areas, consolidate the waste, and cap it with clean fill from an adjacent area. The Project Area is composed of 5 distinct areas: 1) Rotelli Primary Burn Dump Area (Primary Area), 2) Secondary Burn Dump Area (Secondary Area), 3) Borrow Area, 4) Consolidation Area, and 5) Construction Staging Area, as well as access roads and stream areas receiving improvement. At the start of remediation activities, the Primary Area, Secondary Area, Consolidation Area, and Borrow Area would be cleared and grubbed, and all trees would be removed. Transport of waste and clean soil within the Project Area would occur along the existing access roads between the Staging Area, Borrow Area, the 2 burn dump areas, and the Consolidation Area. The grading of the final soil cover would consist of an approximately 60-foot-wide by 200-foot-long flat area that slopes to the east at approximately 4 percent. The side slopes of the final cover would be between 3:1 and 3.5:1 horizontal to vertical (H:V). After placement and compaction of excavated burn waste and cover soil is completed, the final cover soil would be graded to achieve slope gradients of 3:1 H:V or less to promote positive drainage patterns and reduce erosion potential. Following the placement of the final cover, the existing road near the southeastern corner of the Consolidation Area would be extended and re-established on the final cover through the Consolidation Area. The portion of access road within the Consolidation Area would have a width of 16 feet and be resurfaced with an aggregate base. A ditch would be installed along the newly constructed access road that would direct stormwater runoff to the existing culvert (southern culvert) directly east of the Construction Staging Area that passes under the access road towards SR-49. Stormwater improvements would include improvements to 2 existing ephemeral drainages that run through the existing waste limits. Within the Primary Area, after the waste is removed from the northernmost ephemeral drainage, the existing drainage would be reconstructed as a trapezoidal stream channel lined with rock-slope protection. At the downstream end of the north ephemeral drainage the entrance to the culvert (north culvert) would be reinforced with additional rock. This culvert also drains under SR-49. Erosion control measures such as fiber rolls and hydroseeding would be put in place. Within the Consolidation Area, a stabilized topsoil cover is proposed to help reduce the potential for erosive forces that could expose waste. Within the Secondary Area, after the waste is removed from the ephemeral drainage, the drainage would be reestablished to its connection with the culvert draining to and under SR-49 (south culvert). The drainage would be covered with a temporary erosion control mat and hydroseeded with a native seed mix, unless otherwise directed by regulatory agencies during permitting. The existing drop inlet and culvert would be cleaned which also receives stormwater from the new roadside ditch extended from the Consolidation Area.