Big Flat Road (County Route 405) Post Mile 3.6 at Hurdygurdy Creek Bridge Replacement Project

Natural Environment Study

Del Norte County, California Township 15 North, Range 2 East, Section 1 USGS Cant Hook Mountain, California 7.5-Minute Quadrangle 01-DN-0-CR BRLO 5901 (045)

June 2015

Summary

Summary

The County of Del Norte Community Development Department – Engineering Division (County) is planning to replace the Bridge No. 01C-0031 on Big Flat Road (County Route 405) over Hurdygurdy Creek, which is in the Six Rivers National Forest. The County has nominated this bridge for replacement under the federal-aid Highway Bridge Program administered by the Federal Highway Administration through California Department of Transportation (Caltrans) Local Assistance. In 2009, the bridge was found structurally deficient with a rating of 38.5 and the County determined replacement is the most cost- effective solution. The County is proposing to replace this bridge with a structure capable of meeting all requirements of the Caltrans Local Programs Manual and Highway Bridge Replacement and Rehabilitation Program.

A delineation of waters of the United States was conducted to determine if jurisdictional features were present in the biological study area (BSA). Jurisdictional waters mapped within the BSA include perennial stream (Hurdygurdy Creek), intermittent stream and riparian wetland. These features occupy 0.776 acre of the BSA. Placement of rock slope protection below the proposed bridge would result in permanent impacts on up to 0.0115 acre of waters of the United States. Placement of temporary gravel work pads/stream diversions and the temporary road would result in temporary impacts up to 0.1096 acre of waters of the United States. Although the addition of rock slope protection would result in direct permanent impacts on up to 0.0115 acre of waters of the United States, the proposed project will have no net permanent loss of wetlands due to the replacement of riparian vegetation on site at a 3:1 ratio and replacement of a two-span bridge with a new, single-span bridge. The project design minimized impacts on wetlands to the extent practicable. All other design considerations would have a greater impact on wetlands. The project design with the least impact on wetlands was selected and, the project is in compliance with the Wetlands Only Practicable Finding Alternative pursuant to Executive Order 119900, Protection of Wetlands (1977).

Riparian habitat, which is considered a sensitive natural community by the U.S. Army Corps of Engineers and California Department of Fish and Wildlife, is also present in the BSA. Potential impacts to this sensitive community and recommended avoidance measures are addressed.

A Biological Assessment/Essential Fish Habitat Assessment was prepared, which concluded that the proposed project may affect, but is not likely to adversely affect southern Oregon/northern California coast coho salmon (Oncorhynchus kisutch), or their critical habitat, and is not likely to eliminate or significantly diminish or disrupt essential fish habitat

Big Flat Road (County Route 405) at Hurdygurdy Creek Bridge Replacement Project i Summary

(EFH). The National Marine Fisheries Service (NMFS) issued a Biological Opinion on August 18, 2014 that concurred with the determination of may affect, but is not likely to adversely affect southern Oregon/northern California Coast coho salmon or their critical habitat under Section 7 of the Federal Endangered Species Act. Additionally, NMFS determined that the proposed project would not adversely affect EFH for coho salmon.

A Biological Assessment (BA) was prepared to evaluate potential project effects on northern spotted owl (Strix occidentalis caurina), marbled murrelet (Brachyramphus marmoratus), and Pacific fisher West Coast DPS (Martes pennanti). The BA included a habitat assessment for each species and an auditory and visual disturbance evaluation for northern spotted owl and marbled murrelet. Based on the effects evaluation, the BA concluded that the proposed action may affect, but would not likely adversely affect northern spotted owl and marbled murrelet. Additionally, the BA determined that the proposed action may affect, but would not likely adversely affect, designated critical habitat for northern spotted owl and marbled murrelet. Caltrans District 1 submitted the BA to the U.S. Fish and Wildlife Service (USFWS) for review and comment. The USFWS responded that the project complied with the existing Programmatic Informal Consultation for the California Department of Transportation’s Routine Maintenance and Repair Activities, and Small Projects Program for Districts 1 and 2 (U.S. Fish and Wildlife Service 2014). Further, the USFWS recommended that Caltrans District 1 utilize the Programmatic Letter of Concurrence to document Section 7 federal Endangered Species Act compliance. Because Pacific fisher is not currently listed, Caltrans District 1 on behalf of the County will seek concurrence from the USFWS for the species should it be listed in the future, prior to the project being constructed.

A botanical survey conducted on June 25 and September 12, 2012 concluded that no special- status plant or U.S. Forest Service Sensitive or Survey and Manage plant species occur in the biological study area. Based upon the review of habitat requirements and the results of the field assessments, the BSA contains potential habitat for 20 other special-status animals species: western bumble bee (Bombus occidentalis), Chace juga (Juga chacei), Pacific lamprey (Entosphenus tridentatus tridentatus), western brook lamprey (Lampetra richardsoni), coastal cutthroat trout (Oncorhynchus clarkii clarkii), Klamath Mountains Province steelhead DPS (Oncorhynchus mykiss), southern Oregon/northern California coastal Chinook salmon (Oncorhynchus tshawytscha), western tailed frog (Ascaphus truei), Del Norte salamander (Plethodon elongatus), northern red-legged frog (Rana aurora), foothill yellow-legged frog (Rana boylii), southern torrent salamander (Rhyacotriton variegatus), northern goshawk (Accipiter gentilis), black swift (Cypseloides niger), Vaux’s swift (Chaetura vauxi), yellow warbler (Dendroica petechia brewsteri), yellow-breasted chat

Big Flat Road (County Route 405) at Hurdygurdy Creek Bridge Replacement Project ii Summary

(Icteria virens), Sonoma tree vole (Arborimus pomo), ring-tailed cat (Bassariscus astutus), and Humboldt marten (Martes americana humboldtensis). Potential impacts and recommended avoidance and minimization measures for the species listed above are addressed.

The riparian and forest habitats in and near the BSA provide nesting habitat for migratory birds and raptors, which could result in active nests that could be disturbed during project construction if they are present. Potential impacts and recommended avoidance and minimization measures for the species listed above are addressed.

Big Flat Road (County Route 405) at Hurdygurdy Creek Bridge Replacement Project iii Table of Contents

Table of Contents

Summary ...... Summary i Chapter 1. Introduction ...... 1 1.1. Project History ...... 1 1.1.1. Existing Facility Conditions ...... 1 1.2. Project Description ...... 3 1.2.1. Project Overview...... 3 1.2.2. Construction Overview ...... 6 1.2.3. Construction Practices and Conservation Measures ...... 9 Chapter 2. Study Methods ...... 14 2.1. Federal Regulatory Requirements ...... 14 2.1.1. Federal Endangered Species Act ...... 14 2.1.2. Clean Water Act ...... 14 2.1.3. Migratory Bird Treaty Act ...... 15 2.1.4. National Forest Management Act ...... 15 2.1.5. Six Rivers National Forest Land Resource Management Plan ...... 15 2.1.6. Six Rivers National Recreation Area Management Plan ...... 16 2.1.7. Northwest Forest Plan ...... 17 2.1.8. Executive Order 11990 (Wetlands) ...... 17 2.1.9. Executive Order 13112 (Invasive Species) ...... 17 2.1.10. Executive Order 11988 (Floodplain Management) ...... 18 2.2. California Regulator