Mitigation Proposal Warren Ck Timber Gulch Culvert.Pdf

Proposed Warren Creek and Timber Gulch Culvert Replacement Projects; Evaluation and Identification of Suitable Wetlands and Waters Compensation Sites for Impacts to Wetlands and Waters

Type and Amount of Impacts

Warren Creek

There will be approximately 0.01 acres of permanent impacts to the Warren Creek streambed, which is considered a coastal wetland according to the California Coastal Act (Coastal Act) definition and the Sonoma County Local Coastal Plan (LCP). This will be compensated for at a 3:1 ratio, a standard for permanent impacts to wetlands, for a total of 0.03 acres of wetlands.

Timber Gulch

There will be approximately 0.03 acres of permanent impacts to the Timber Gulch streambed, which is considered coastal waters according to the Coastal Act and the Sonoma County LCP. Caltrans proposes to compensate this impact at a 3:1 ratio for a total of 0.09 ac of waters enhancement.

Caltrans will restore temporary impacts on Warren Creek and Timber Gulch through onsite recontouring and revegetation of all temporarily disturbed streambed and undeveloped areas. Hydroseeding with natives or locally appropriate naturalized species will occur at the end of the project and immediately before the onset or at the beginning of the rainy season to maximize the success of the plantings and minimize potential soil erosion. The actual schedule may vary somewhat due to the timing of construction, funding, and contracting.

Potential for Onsite Enhancement

The waters and surrounding habitat for both Warren Creek and Timber Gulch were intact and there are no practical ways to improve ecological functionality in these areas without altering the character of the existing coastal habitat. One exception is the erosion control features of the projects themselves.

Warren Creek

The Warren Creek project area consists of a stream corridor surrounded by wetlands and coast redwood (Sequoia sempervirens) and northern bishop pine (Pinus muricata) forest. In accordance with the Coastal Act and LCP wetland definitions, the jurisdictional wetlands within the disturbance area boundary include Warren Creek and the maximum extent of the slough sedge (Carex obnupta). Slough sedge is a common coastal wetland species and occurs in dense clumps around the culvert inlet and along the outlet side of Warren Creek. It is thriving at this location and does not require additional planting.

PROPOSED ENHANCEMENT PROJECTS: 3S7511 AND 3S7521 - Timber Gulch

The Timber Gulch channel is characterized by a rocky substrate comprised predominantly of large cobbles and boulders, with some smaller gravel. In-stream planting is not appropriate for this location. Coastal woodlands surround the Timber Gulch streambed, with redwoods as the dominant tree species and an open understory consisting of western sword fern (Polystichum munitum), redwood oxalis (Oxalis oregana), trillium (Trillium sp.), and lady fern (Athyrium felix-feminay. The coastal woodlands are intact and do not require additional planting or weed removal.

Offsite Compensation

Caltrans staff researched alternative sites, looking specifically for ones as close to the project areas as possible. California State and County Parks, the Sonoma County Permit and Resource Management Department, and the California Coastal Commission were contacted for recommendations.

Two areas were identified as suitable compensation for the Warren Creek and Timber Gulch projects. Both of these proposals were developed in coordination with California State Parks:

• Ecological enhancement to a nearby wetland, at Fort Ross State Park (Attachment 1) as compensation for wetland impacts due to the Warren Creek project. • Contributing to the Willow Creek Enhancement Project (Attachment 2) as compensation for coastal waters impacts due to the Timber Gulch project.

These projects would enhance habitats affected by the projects, coastal wetlands in the case of Warren Creek, and coastal waters for Timber Gulch. Both are within 10 miles of the impacted area and they would enhance a similar coastal ecosystem.

Despite contacting federal, state, and local agencies and other attempts to identify additional coastal enhancement opportunities, we are aware of no other suitable projects in the region. The major limitations to finding suitable compensation sites were the relatively small amount of impacts, site restrictions at the potential compensation sites,and the lack of existing mitigation/compensation banks along this section of the coast.

The enhancement projects presented here are ecologically valuable, timely, and financially viable and for these reasons, we would like to move forward with them.

PROPOSED ENHANCEMENT PROJECTS: 3S7511 AND 3S7521 AITACHMENT 1: DRAFT PROPOSED WETLAND RESTORATION AT FORT Ross STATE HISTORIC PARK FOR IMPACTS TO WETLANDS AT WARREN CREEK

Background: A potential coastal wetlands restoration project has been identified for the proposed Warren Creek Culvert Replacement Project (EA 3S7521), as a result of coordination between Caltrans Biology, Caltrans coastal permitting, and California State Parks staff.

The purpose of the restoration project is to compensate for impacts to coastal wetlands due to the Warren Creek Culvert Replacement Project. The restoration project was selected due to the proximity to the project location (SON 1, PM 40.13), the similarity in habitat type to the impacted area, size of the project, and its ecological and financial viability.

Proposed Restoration Project: The project would be located at Fort Ross State Park, adjacent to Highway 1 at approximately post mile 33 in Sonoma County. Parts of the park are fenced off from the public and used instead for cattle grazing, based on an historic grazing permit. The cows currently drink from a natural spring and sag pond that drain to Fort Ross Creek and ultimately to the Pacific Ocean. The creek supports special status species such as anadromous fish and potentially California red-legged frogs (Rana draytonii).

The grazing degrades the adjacent sensitive wetland vegetation and also reduces the water quality, leading to sedimentation and nitrogen loading of the water. The restoration would enhance wetland habitat and improve water quality along the creek.

The restoration project would include installing exclusionary fencing to the natural spring and sag pond, installing two water troughs and metal piping to feed the troughs, as well as subsidizing salary for State Park staff to manage and implement the project. Restoration would also include hydrophytic plantings of willow around the sag pond to promote re-growth of wetland vegetation. Caltrans staff would be responsible for monitoring and reporting the status of the project to agencies.

The restoration footprint around the sag pond is 0.36 acres (1450 square meters). The fencing needed is approximately 952 feet (290 meters). The restoration need, as currently in Caltrans Coastal Development Permit application, is only 0.03- based in a 3: 1 ratio of 0.01 acres of permanent impacts on coastal wetlands.

- Fort Ross State Historic Park Orchard Spring Development Project

• ••

Fencing ~ Water course N Sag Pond • Restoration Footpri nt Orchard Pipeline Trough

0 50 100 200 Meters en o z

_. _.r+ (Ca_. o ::J _.(J'J r+ (1) EA 3S7521 SON 1 Warren Creek - Fort Ross Mitigation Site (5/12/2010) -

en o z

,...._. (Q _.a o :J en,...._. CD EA 357521 SON 1 Warren Creek - Fort Ross Mitigation Site (5/12/2010) EA 357521 SON 1 Warren Creek - Fort Ross Mitigation Site (5/12/2010) Attachment 2: Willow Creek Enhancement Project

EXHIBIT "B"

TASKS TO BE PERFORMED BY STATE PARKS

1. Invasive Species Control

• Control invasive species in priority habitats within the Russian River District. Includes but not limited to; brooms, thistles, spurges, ice plant, European beachgrass, cape ivy, bullfrogs, feral pigs

2. Upslope Sediment Reduction Planning

• Survey remaining road and skid trail network (estimated at approximately 25 miles) and other sources of erosion for sediment savings opportunities • Implement upgrades and decommissioning on newly identified priority sites

3. Riparian Enhancement

• Improve riparian habitat within 217 acres

4. Stream Enhancement

• Improve up to eight miles of in-stream habitat through appropriate placement of large wood in stream • Improve stream channel complexity, fish habitat values, and sediment storage capacity

5