Conceptual Approaches for Short- and Long- Term Erosion and Sediment Control Big River State Park At Big River State Park, DPR and the State of California have acquired industrial timberlands that were intensely managed for 150 years. Future management of these lands will require an approach commensurate with the industrial management of the past.

Roads and watercourse crossings have the greatest potential for erosion and sediment delivery within the park boundaries. The conceptual approaches to addressing short-term erosion potential are focused on immediate concerns regarding the roads and watercourse crossings. Conceptual approaches for the long-term are also focused on the roads but include aspects of long-term monitoring as well. Conceptual Approaches for Short- and Long- Term Erosion and Sediment Control Big River State Park

Short-Term Erosion Control Measures Emergency repairs Maintenance and periodic inspections of inside ditches, waterbars and culverts following major rain events. Explore options to cost share maintenance and repairs. Remove/repair all high priority watercourse crossings. Monitor high priority road segments along Big River at sensitive sites.

Short-Term Erosion Control Measures (continued) Encourage and train stewardship volunteers to be roadway inspectors and thus assist DPR maintenance crews.

Long-Term Erosion Control Measures Continued annual maintenance of the roads and watercourse crossings. Ongoing monitoring program of roads and watercourse crossings. Decommissioning and abandonment of roads and watercourse crossings. Characterize and monitor landings to minimize fill mobilization. Repair of major road failures or landslides to maintain vehicle conveyance and reduce the potential for sediment delivery to watercourses.

Long-Term Erosion Control Measures (continued) Repair moderate priority sites after high priority sites have been addressed. Consult with professional foresters to assist in transitioning these industrial timberlands into self- sustaining natural forests.

Roads Recommended to be Maintained for Vehicle Access. Main Access Road (M1 and M14) High Chute Ridge Road (HC1.0). Road S22.0 Road L4.0 Road (L1.0) Roads in and around the Mendocino Woodlands.

The type and extent of road and watercourse crossing repairs are dependent upon the intended long-term use of the road. The extent of road/crossing repairs required should be considered when deciding on the eventual fate of the road. Considerations

Roads that require considerable repairs and are not required for vehicle patrol should be considered for decommissioning or trail conversion. Roads that require considerable repairs but are required for patrol may become a higher priority for repairs. Recommendations

Repair Options for High Priority Road Segments Excavation and recompaction of existing embankment fills. Repair of small cut-bank or fill-slope failures. Realignment of the road to a more stable location. Removal or reshaping the outside road edge fill. Excavated fill can be repositioned along the running surface, using it to fill the inside ditch, or placing and recontouring material along the inboard side of the road.

Repair Options for High Priority Road Segments (continued) High priority roads may be useable in the present condition, but these segments should be monitored regularly. Example: Road M1.0, at Alder Alley, where the road is positioned on an over-steepened slope immediately adjacent to the outside meander bend of the Big River.

Repair Options for Low Priority Roads Road segments that require minimal repairs, but that are required for public access and safety can, in most cases, be used in the present condition. Roads segments not required for public access and safety, should be considered for trail conversions. The running surface generally requires only minimal attention and can be used in the current condition for either vehicle or trail use. Low-priority dead end roads that have no watercourse crossings could be left untreated and allowed to revegetate and stabilize naturally.

Best Management Practices Roads and crossing need to be repaired and maintained using the Best Management Practices (BMP). BMPs are general techniques or design practices that will prevent or reduce pollution and maintain water quality. Most BMPs are also sound engineering practices and are cost-effective by preventing failures and reducing maintenance needs and repair costs.

Site Access When making decisions regarding road repair priorities or decommissioning, site access is an important consideration to keep in mind. Road decommissioning or trial conversions should be delayed if it would prevent site access necessary for restoration. Roads to recently logged areas may need to be maintained to facilitate management activities (vegetation and slash removal) required for both forest vitality and fire prevention.

Watercourse Crossings High-priority watercourse crossings were identified on virtually all of the roads. All high-priority watercourse crossings are likely to fail in the short term, limiting passibility and causing adverse impacts. Many of these crossings have impounded significant volumes of sediment. This sediment can be expected to be released if the crossing should fail, further exacerbating the environmental impacts downstream.

Repair Options for These High Priority Watercourse Crossings Complete reconstruction of the crossing Culvert replacement Add energy dissipater to the outlet Placement of rock armor on eroding fill slopes Complete removal culvert and fill Replace with trails that bypass the former crossing location, rock fords or bridges

Completely Clogged Ditch Relief Culvert