Exhibit E-3 Calero County Park Pond and Wetland Restoration Project Mitigation and Monitoring Plan
Pond and Wetland Restoration Calero County Park Bid Package – E. Design Plans, Specifications, and Mitigation and Monitoring Plan Exhibit E-3 Mitigation and Monitoring Plan
Calero County Park Pond and Wetland Restoration Project Mitigation and Monitoring Plan
Project # 3753-01
Prepared for:
Edmund Sullivan, Executive Officer Santa Clara Valley Habitat Agency 535 Alkire Avenue, Suite 100 Morgan Hill, California 95037
Prepared by:
H. T. Harvey & Associates
In collaboration with:
cbec eco-engineering, Inc.
April 26, 2016
983 University Avenue, Building D Los Gatos, CA 95032 Ph: 408.458.3200 F: 408.458.3210 Table of Contents
Section A. Title Page ...... 1 Section B. Contributor Information ...... 2 Section C. Regulatory Agency Distribution ...... 3 Section D. Brief Description of Proposed Compensatory Mitigation Site and Proposed Source of Compensatory Mitigation ...... 4 Section E. Objectives ...... 8 Section F. Description of Site Selection Criteria ...... 13 Section G. Description of Landscape Position of Mitigation Site ...... 15 Section H. Mitigation Site Specific Information and Baseline Information ...... 16 Section I. Other Baseline Information ...... 32 Section J. Mitigation Work Plan ...... 34 Section K. Determination of Credits ...... 62 Section L. Site Protection Instrument ...... 63 Section M. Maintenance Plan ...... 64 Section N. Ecological Performance Standards ...... 68 Section O. Monitoring Requirements ...... 72 Section P. Long Term Management Plan ...... 77 Section Q. Adaptive Management Plan ...... 78 Section R. Financial Assurances ...... 79 Section S. Other Information ...... 80 Section T. References ...... 81 Section U. Attachments ...... 83
Tables
Table 1a. Pond Mitigation Site Description for Permittee Responsible Mitigation in the IMS ...... 10 Table 1b. Wetland Mitigation Site Description for Permittee Responsible Mitigation in the IMS ...... 11 Table 2. Seep Flow Rate Measurements ...... 19 Table 3. Project Impacts ...... 49 Table 4. Pond Mitigation site - Wetland Plant Species Palette ...... 52 Table 5. Wetland Mitigation site - Wetland Plant Species Palette ...... 53 Table 6. Sitewide Erosion Control Seeding Mix ...... 54 Table 7. Mt. Hamilton Thistle Seed Mix ...... 54 Table 8. Itemized Budget Estimate ...... 58 Table 9. Number and Resource Types of Credits Established ...... 62 Table 10. Maintenance Schedule Years 1-5 ...... 66 Table 11. Annual Maintenance Costs Table...... 67 Table 12. Ecological Performance Standards Monitoring Schedule ...... 70
Calero County Park Pond and Wetland H. T. Harvey & Associates i Restoration Project MMP April 26, 2016 Figures
Figure 1. Pond and Wetland Mitigation Sites Vicinity Map ...... 6 Figure 2. USGS Topography Map ...... 7 Figure 3. Pond Mitigation Site Hydrologic Regimes ...... 17 Figure 4. Hydrology Gage Locations...... 21 Figure 5. Pond Mitigation Site – Existing Conditions ...... 25 Figure 6. CNDDB Occurrences of CRLF and CTS Near Project Site ...... 28 Figure 7. Wetland Mitigation Site – Existing Conditions ...... 31 Figure 8. Pond Mitigation Site – Conceptual Plan ...... 37 Figure 9. Pond Mitigation Site- Conceptual Pond Grading and Hydrologic Infrastructure Improvement Plan ...... 40 Figure 10. Pond Mitigation Site – Outlet Works Typical Detail ...... 41 Figure 11. Wetland Mitigation Site – Conceptual Plan ...... 44 Figure 12. Wetland Mitigation Site – Conceptual Grading Plan ...... 47 Figure 13. Himalayan Blackberry Scrub on the Berm at the Pond Mitigation Site (October 2015)...... 57
Calero County Park Pond and Wetland H. T. Harvey & Associates ii Restoration Project MMP April 26, 2016 Section A. Title Page
Mitigation Site Name: Calero County Park Pond and Wetland Restoration Project
Department of Army Permit Number: Santa Clara Valley Habitat Plan Regional General Permit. File No. SPN-2012-00302S
Applicant’s Name: Edmund Sullivan, Executive Officer, Santa Clara Valley Habitat Agency
Applicant’s Address: 535 Alkire Avenue, Suite 100, Morgan Hill, CA 95037
Applicant’s Phone Numbers: (408) 779-7261
Mitigation and Monitoring Plan Preparer/Contact: Max Busnardo, M.S., Principal Restoration Ecologist, H. T. Harvey & Associates
Preparer’s Address: 983 University Avenue, Bldg. D, Los Gatos, CA 95032
Preparer’s Phone Number: (408) 458-3222
Date of most recent revision to the Mitigation Plan: March 31, 2016
Calero County Park Pond and Wetland H. T. Harvey & Associates 1 Restoration Project MMP April 26, 2016 Section B. Contributor Information
B.1 Persons Names Who Prepared the Mitigation Plan
H. T. Harvey & Associates Max Busnardo, M.S., Principal Restoration Ecologist, 983 University Avenue, Bldg. D, Los Gatos, CA 95032; (408) 458-3222; [email protected]
Karen Verpeet, M.L.A, Project Manager, Senior Landscape Architect, 983 University Avenue, Bldg. D, Los Gatos, CA 95032; (408) 458-3227; [email protected]
Will Spangler, B.A., Restoration Ecologist, 983 University Avenue, Bldg. D, Los Gatos, CA 95032; (408) 458- 3255; [email protected] Jeff Wilkinson, Ph.D., Senior Herpetologist, 983 University Avenue, Bldg. D, Los Gatos, CA 95032; (408) 458- 3228; [email protected] Steve Rottenborn, PhD., Senior Wildlife Ecologist, 983 University Avenue, Bldg. D, Los Gatos, CA 95032; (408) 458-3205; [email protected] Patrick Boursier, PhD., Senior Botanist, 983 University Avenue, Bldg. D, Los Gatos, CA 95032; (408) 458- 3204; [email protected]
cbec eco-engineering, inc. Chris Campbell, M.S., Principal, 2544 Industrial Boulevard, West Sacramento, CA 95691; (916) 231-6052; [email protected]
Sam Diaz, B.S., Ecohydrologist, 2544 Industrial Boulevard, West Sacramento, CA 95691; (916) 231-6052; [email protected]
ICF Kathryn Gaffney, Conservation Planner, 101 Lucas Valley Road, Suite 260, San Rafael, CA 94903; (415) 507- 7131; [email protected] Torrey Edell, Botanist and Permitting Specialist, 75 E Santa Clara St #300, San Jose, CA 95113; (408) 216- 2829; [email protected]
Resource Conservation District of Santa Cruz County Kelli Camara, Program Director, 820 Bay Ave #136, Capitola, CA 95010; (831) 464-2938 x 15; [email protected]
Calero County Park Pond and Wetland H. T. Harvey & Associates 2 Restoration Project MMP April 26, 2016 Section C. Regulatory Agency Distribution
Sahrye Cohen U.S. Army Corps of Engineers (USACE), San Francisco District Regulatory Branch 1455 Market Street, 16th Floor San Francisco, CA 94103-1398 [email protected]
Joseph Terry U.S. Fish and Wildlife Service (USFWS) 2800 Cottage Way, Suite W-2605 Sacramento, CA 95825-1846 [email protected]
Brian Wines San Francisco Bay Regional Water Quality Control Board (RWQCB) 1515 Clay Street, Suite 1400 Oakland, CA 94612 [email protected]
Jon Rohrbough Central Coast RWQCB 895 Aerovista Place, Suite101 San Luis Obispo, CA. 93401-7906 [email protected]
Craig Weightman California Department of Fish & Wildlife (CDFW), Bay Delta Region 7329 Silverado Trail Napa, CA 94558 [email protected]
Dave Johnston Same address as for Craig Weightman [email protected]
Brenda Blinn Same address as for Craig Weightman [email protected]
Calero County Park Pond and Wetland H. T. Harvey & Associates 3 Restoration Project MMP April 26, 2016
Section D. Brief Description of Proposed Compensatory Mitigation Site and Proposed Source of Compensatory Mitigation
D.1 Mitigation Site Name
Calero County Park Pond and Wetland Restoration Project
D.2 Location of and Directions to Mitigation Site
The project is composed of two specific mitigation sites located in the northwest portion of Calero County Park (Figure 1). The address of Calero County Park is 23205 McKean Road, San Jose, Santa Clara County, CA 95120. The access road to the mitigation sites is located at Latitude 37°11’38.81” N and Longitude 121°58’22.48” W.
D.3 Other Location Description
Assessor’s Parcel Numbers for the mitigation sites are 74209049 and 74209050. All areas of the project site are located on the Santa Teresa Hills, California U.S. Geological Survey quadrangle map, Section 36 of Township 8 South, Range 1 East (Figure 2).
D.4 Brief Description of Proposed Compensatory Mitigation Site
The Santa Clara Valley Habitat Agency (Habitat Agency) identified a pond and wetland restoration project at Calero County Park as a priority project for the implementation of the Conservation Strategy of the Santa Clara Valley Habitat Plan (Habitat Plan) (ICF 2012). The project site was selected in partnership with the Santa Clara County Parks and Recreation Department, U. S. Fish and Wildlife Service, California Department of Fish and Wildlife, and the Resource Conservation District of Santa Cruz County. The Calero County Park Pond and Wetland Restoration project will restore pond and wetland habitats at two locations (an existing pond site and an existing wetland site) in Calero Country Park, located in the eastern foothills of the Santa Cruz Mountains in the Alamitos Creek watershed (Figure 1).
The pond mitigation site is currently heavily grazed by cattle, has a limited duration of ponding and is occupied by invasive aquatic predators; all of which reduces habitat quality for the following Habitat Plan covered species: the California red-legged frog (Rana draytonii), California tiger salamander (Ambystoma californiense), western pond turtle (Actinemys marmorata), and Mt. Hamilton thistle (Cirsium fontinale var. campylon). The pond restoration objectives include restoration of breeding habitat for the California red-legged frog and California tiger salamander, restoration of various wetland habitat functions including habitat for the Mt. Hamilton thistle, establishment (i.e., creation) of new seasonal wetland habitat, establishment of basking habitat for the western
Calero County Park Pond and Wetland H. T. Harvey & Associates 4 Restoration Project MMP April 26, 2016
pond turtle, improvement of pond habitat climate change resiliency, and provision of water for cattle that graze the surrounding Calero Reserve. The Habitat Agency proposes the following actions at the pond mitigation site to accomplish these objectives: 1) using fencing to exclude cattle from a portion of the pond, 2) excavating the open water portion of the pond to increase ponding depth and duration and installing basking logs for western pond turtle, 3) excavating uplands at the pond fringe to establish new seasonal wetlands, 4) replacing the pond outfall structure and incorporating a new drain so that the deepened pond may be drained for aquatic predator control, 5) excavating a ditch and installing natural grade control structures to increase seep inflow, 6) revegetating the pond fringe with native wetland vegetation, and 7) long-term habitat management (in perpetuity).
The wetland mitigation site is currently heavily grazed and subject to sedimentation largely due to access by cattle. The wetland restoration objectives include restoration of wetland habitat functions, establishment of new seasonal wetland habitat, restoration of foraging and dispersal habitat for the California red-legged frog, improvement of wetland habitat climate change resiliency, and the provision of water for cattle that graze the surrounding Calero Reserve. The Habitat Agency proposes the following actions to accomplish these objectives: 1) using fencing to exclude cattle from the wetland, 2) excavating uplands adjacent to existing wetlands to establish new wetlands, 3) excavating sediment within existing wetlands to restore California red- legged frog foraging habitat, 4) revegetating the site with native wetland vegetation, and 5) long-term habitat management (in perpetuity).
Calero County Park Pond and Wetland H. T. Harvey & Associates 5 Restoration Project MMP April 26, 2016 San Rafael MARIN CONTRA COSTA Detail Stockton San Francisco Oakland California SAN FRANCISCO SAN JOAQUIN ALAMEDA Redwood City
S A N M A T E O San Jose STANISLAUS
SANTA CLARA
S A N T A C R U Z Project Vicinity Santa Cruz MERCED
Hollister
Pacific S A N B E N I T O Ocean Salinas
MONTEREY
0 20
Miles
Project Location
Calero Reservoir
Almaden Reservoir
5,000 2,500 0 5,000
Feet N:\Projects3700\3753-01\Reports\MMP\Figure 1Pond and WetlandMitigation Sites Vicinity Map.mxd mchilds Figure 1. Pond and Wetland Mitigation Sites Vicinity Map Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016 Legend
Project Location
2,000 1,000 0 2,000
Feet N:\Projects3700\3753-01\Reports\MMP\Figure 2USGS Topography Map.mxd mchilds Figure 2. USGS Topography Map Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016 Section E. Objectives
The Habitat Agency will implement the project to achieve the below objectives. The habitat objectives are characterized according the definitions of the terms “restoration” and “establishment” in the Regional Compensatory Mitigation and Monitoring Guidelines for South Pacific Division (USACE 2015). These definitions are similar to those used by other permitting resource agencies. The project will show significant progress toward these objectives within 5 years of construction, although long-term achievement of these habitat objectives may take decades.
Pond Mitigation Site • Restore breeding habitat for the California red-legged frog and California tiger salamander by deepening the pond, increasing seep water inflow, planting wetland vegetation, controlling aquatic predators, and excluding cattle from a portion of the pond. The deepened pond will also restore breeding habitat for common amphibians such as the Sierran chorus frog (Pseudacris sierra) and western toad (Anaxyrus boreas).
• Restore seasonal wetland and freshwater marsh habitats by excluding cattle and planting native wetland vegetation. These actions will restore multiple wetland functions, including sediment filtration, nutrient filtration, erosion protection, and provision of habitat for Mt. Hamilton thistle, foraging and dispersal habitat for the California red-legged frog, and foraging habitat for seasonal wetland associated birds.
• Establish seasonal wetland habitat by converting upland habitat to wetlands to establish multiple wetland functions, including sediment filtration, nutrient filtration, erosion protection, provision of habitat for Mt. Hamilton thistle, breeding, foraging and dispersal habitat for the California red-legged frog, and foraging habitat for seasonal wetland associated birds.
• Establish functional basking habitat for the western pond turtle by installing anchored basking logs in the deepened open water portion of the pond.
• Improve climate change resiliency of pond habitat by increasing the water storage capacity of the pond and by increasing the springbox/seep inflow rate to the pond.
• Continue to provide water for cattle that graze the surrounding Calero Reserve.
Wetland Mitigation Site • Restore seasonal wetland and freshwater marsh habitats by removing sediment, planting native wetland vegetation, and excluding cattle. These actions will restore multiple wetland functions including sediment filtration, nutrient filtration, provision of habitat for Mt. Hamilton thistle, foraging and dispersal habitat for the California red-legged frog, and foraging habitat for seasonal wetland associated birds.
• Establish seasonal wetland habitat by converting upland habitat to wetlands to establish multiple wetland functions including sediment filtration, nutrient filtration, erosion protection, provision of habitat for Mt.
Calero County Park Pond and Wetland H. T. Harvey & Associates 8 Restoration Project MMP April 26, 2016 Hamilton thistle, foraging and dispersal habitat for the California red-legged frog, and foraging habitat for seasonal wetland associated birds.
• Improve climate change resiliency of wetland habitat by increasing the water storage capacity of the wetland.
• Continue to provide water for cattle that graze the surrounding Calero Reserve.
E.1 Aquatic Resources to be Provided
Table 1a/1b lists the aquatic resource types that will be provided at the pond and wetland mitigation sites. The resource type is characterized according to the Habitat Plan land cover types, which is similar to the aquatic resources types provided by USACE.
E.2 Method of Compensatory Mitigation
a. Establishment: ☒
b. Re-establishment: ☐
c. Restoration: ☒
d. Preservation: ☐
Calero County Park Pond and Wetland H. T. Harvey & Associates 9 Restoration Project MMP April 26, 2016 E.3 Resource Type Description Tables
Table 1a. Pond Mitigation Site Description for Permittee Responsible Mitigation in the IMS
Site No. Pre-Construction Post-Construction Site Conditions Site Conditions Pond Habitat Types Habitat Vegetation Hydrology Mitigation Acres Mitigation Types Method Site Wetland Waters of the U.S. P1 Seasonal Seasonal Juncus Ephemeral Restoration 0.165 wetland wetland arcticus/Juncus xiphioides alliance P2 California Seasonal Juncus Ephemeral Establishment 0.013 annual wetland arcticus/Juncus grassland xiphioides alliance P3 Coastal and Coastal Cirsium fontinale Perennial Restoration 0.056 valley and valley alliance freshwater freshwater marsh marsh P4 Seasonal Coastal Eleocharis Perennial Restoration 0.047 wetland and valley macrostachya/Sc freshwater irpus microcarpus marsh alliance Total: 0.281 Non-Wetland Waters of the U.S. P5 Ponds Ponds Open water/bare Perennial Restoration 0.219 ground Total: 0.219 Notes: Site numbers are shown on Figure 9.
Calero County Park Pond and Wetland H. T. Harvey & Associates 10 Restoration Project MMP April 26, 2016
Table 1b. Wetland Mitigation Site Description for Permittee Responsible Mitigation in the IMS
Site No. Pre-Construction Post-Construction Site Conditions Site Conditions Wetland Habitat Types Habitat Vegetation Hydrology Mitigation Acres Mitigati Types Method on Site Wetland Waters of the U.S. W1 Seasonal Seasonal Juncus Ephemeral Restoration 0.036 wetland wetland arcticus/Juncus xiphioides alliance W2 Serpentine Seasonal Juncus Ephemeral Establishment 0.017 bunchgrass wetland arcticus/Juncus grassland xiphioides alliance W3 Coastal and Coastal Eleocharis Perennial Restoration 0.060 valley freshwater and valley macrostachya/Scir marsh freshwater pus microcarpus marsh alliance W4 Total: 0.113 Notes: Site numbers shown on Figure 12
E.4 Buffer Area
a. Acreage: 69.065 acres
b. Average Width from Wetland Edge: 500 feet
c. Vegetation Community: Vegetation communities in the buffer area at the pond mitigation site include California annual grassland, coast live oak woodland and forest, and serpentine bunchgrass grassland habitats. Vegetation communities in the buffer area at the wetland mitigation site include serpentine bunchgrass grassland and coast live oak woodland and forest. The Almaden-Calero Canal, seeps, and seasonal drainages occur in the buffer area of both sites.
d. Compensatory Mitigation Method: The buffer area is not compensatory mitigation.
i. Establishment (ES): ☐
ii. Re-establishment (REE): ☐
iii. Restoration (RES): ☐
iv. Preservation (P): ☐
Calero County Park Pond and Wetland H. T. Harvey & Associates 11 Restoration Project MMP April 26, 2016
E.5 Non-Aquatic Compensatory Mitigation Excluding Buffer Areas (Acreage)
The project is not providing non-aquatic compensatory mitigation. However, the project and surrounding area is within Calero County Park and will be protected under a Conservation Easement as the Calero Reserve. As required for all Habitat Plan Reserve System lands, the buffer lands will be managed and monitored at an enhanced level to meet the biological goals and objectives of the Habitat Plan.
E.6 Brief Summary of How the Compensatory Mitigation Will Address Watershed Needs
The Calero County Park Pond and Wetland Restoration project occurs within the Alamitos Creek watershed. The project will address the needs of the watershed by restoring and establishing aquatic and wetland habitats that benefit special status wildlife such as the California red-legged frog, California tiger salamander, western pond turtle, and other wildlife species that rely on aquatic resources. The project will control existing invasive aquatic predators in the pond to reduce their predation on and competition with native wildlife species. Such predator control will benefit aquatic habitats in the surrounding watershed by reducing reproduction and dispersal of aquatic predators. The project will also improve water quality by limiting cattle access in wetland, pond, and seep areas and establishing native wetland vegetation to filter runoff. The project will increase the diversity of native wetland vegetation in the watershed via revegetation and cattle exclusion.
Calero County Park Pond and Wetland H. T. Harvey & Associates 12 Restoration Project MMP April 26, 2016
Section F. Description of Site Selection Criteria
F.1 Location of Proposed Compensatory Mitigation Site
The project location is described in Section D.
F.2 General Watershed Condition
The Alamitos Creek watershed has been subject to historical cattle grazing and other agricultural uses as well as residential development. Portions of the watershed are currently grazed, including the tributary watersheds in which the pond and wetland mitigation sites. Cattle grazing has resulted in trampling and grazing of wetland vegetation in the watershed, degrading wetland functions including wildlife habitat quality and water filtration. Urban-suburban and rural residential development is present in the lower watershed that has resulted in the loss of wetland habitats in the watershed. Historical mining sites and quarries are present in the watershed; the wetland mitigation site is located at an abandoned quarry site. Large scale water diversions have occurred since the construction of dams and reservoirs like the Almaden Reservoir and Calero Reservoir. The Almaden-Calero Canal runs through the watershed and diverts some water that would runoff into the pond mitigation site and conveys it to Calero Reservoir. Surface drainages and seeps have been diverted within the watershed to provide water to support cattle grazing. The loss of these water sources to reservoirs, the canal, and cattle use reduce the water available for wetland habitat in the watershed.
Wetlands and ponds in the Alamitos Creek watershed provide important habitat several Habitat Plan covered species including California red-legged frog, California tiger salamander, western pond turtle, and Mt. Hamilton thistle. The project will restore pond and wetland habitat functions and will establish new seasonal wetland habitat, per the above objectives, to benefit these species. Therefore, the proposed project actions are consistent with the landscape, natural community, and species level goals identified in the Habitat Plan. These include goals to enhance or restore natural and semi-natural landscapes to increase native biological diversity, to enhance and create pond, freshwater marsh, and seasonal wetland habitats that benefit covered species, and to maintain viable populations and contribute to the regional recovery of species such as the California red-legged frog, California tiger salamander, western pond turtle, and Mt. Hamilton thistle.
F.3 Location of Any Invasive Plant Species at or Near the Mitigation Project Site
Nonnative, invasive species are present at the pond mitigation site. A population of Himalayan blackberry (Rubus armeniacus) occurs on the berm slope. Nonnative annual species typically found in California annual grassland habitat occur in the surrounding grasslands, including black mustard (Brassica nigra) and yellow star thistle (Centaurea solstitialis). Nonnative, invasive plant species are not known to be present at the wetland mitigation site.
Calero County Park Pond and Wetland H. T. Harvey & Associates 13 Restoration Project MMP April 26, 2016
Nonnative, invasive plant species will be treated and managed with flash grazing, string trimming, and physical removal in accordance with the methods described in Section J, Section M, and Attachment 8.
F.4 Watershed Size (Area)
The hydrologic unit code (HUC) for the pond and wetland mitigation sites is HUC Coyote 1805003.
Pond Mitigation Site The pond mitigation site is located within the Alamitos Creek watershed. The water sources to the pond mitigation site include both overland flow and seep water inflow from a springbox that conveys seep flow across the Almaden-Calero Canal to the pond via a steel pipe. The contributing watershed directly connected to the pond that provides overland flow is approximately 11.5 acres. The watershed south of the Almaden- Calero Canal and tributary to the springbox is approximately 26.5 acres. During runoff events, the springbox either becomes filled with sediment and debris (plant material) from channelized flow through the riparian zone and/or the 6 inch steel pipe is undersized to handle peak runoff during larger storm events, thereby overwhelming the springbox and spilling directly into the canal. However, the 6 inch pipe is adequately sized to convey seep flows and therefore, will not need to be altered to achieve the project objectives. The hydrologic unit code for the pond and wetland mitigation sites is HUC Coyote 1805003.
Wetland Mitigation Site The wetland mitigation site is also located within the Alamitos Creek watershed. The contributing watershed to the wetland mitigation site is very small (< 0.5 acres) as the wetland is at the base of a quarry excavated into the side of a convex hillslope (laterally and longitudinally). The water source to the wetland is a spring that was unearthed when the hillside was excavated.
Calero County Park Pond and Wetland H. T. Harvey & Associates 14 Restoration Project MMP April 26, 2016
Section G. Description of Landscape Position of Mitigation Site
G.1 Site Topography and Surrounding Land Use
The pond and wetland mitigation sites are located in rolling hills in the eastern foothills of the Santa Cruz Mountains at approximately 550 feet elevation. The pond mitigation site is located at the headwaters of a drainage that is tributary to Alamitos Creek on gently sloping topography which is generally steeper upstream of the pond. A large berm retains surface runoff and seep water in the pond. The wetland mitigation site is located on relatively flat topography below a steep quarried rock slope cut into the hillslope. A ranch road adjacent to the wetland forms an informal berm that retains seep water in the wetland.
Land use surrounding both the pond and wetland mitigation sites is agricultural with a mosaic of grazed grasslands and woodlands. An extensive existing buffer of undeveloped land surrounds the sites. Both sites and their watersheds are located within Calero County Park and will be protected under a Conservation Easement as the Calero Reserve. Rural residential development occurs in the lower watershed, downstream from both sites. The Almaden-Calero Canal is adjacent to both the pond and wetland and periodically conveys water east toward Calero Reservoir. The concrete-lined canal is the nearest adjacent aquatic resource to the pond and wetland during times when the canal is flowing. Numerous ephemeral and perennial seeps occur in the upper watershed and the surrounding hills. A stock pond is located within 1500 feet northeast of the pond and wetland; it is generally inundated for a shorter duration than the pond at the pond mitigation site.
Calero County Park Pond and Wetland H. T. Harvey & Associates 15 Restoration Project MMP April 26, 2016 Section H. Mitigation Site Specific Information and Baseline Information
H.1 Site Information
A PG&E utility easement for overhead utility lines is present adjacent to the wetland mitigation site. Powerline towers are present in the site vicinity, but are not present on the pond or wetland mitigation sites themselves. However, the overhead lines pass directly over the northernmost portion of the wetland mitigation site, and PG&E has an easement to access these lines and drive along the adjacent road. The San Jose Water Company also has an easement located adjacent to, but not overlapping with, the wetland mitigation site.
The Santa Clara Valley Water District owns fee title to the Almaden-Calero Canal that includes an access road running along the north side of the canal, adjacent to the pond mitigation site.
H.2 Hydrology
H.2.1 Existing Hydrologic Regime
Ephemeral: ☒
Intermittent: ☐
Perennial: ☒
The following information was observed by cbec’s hydrologist, Chris Campbell and/or communicated by the cattle rancher on October 27, 2015 and February 10, 2016 and validated with water budget calculations (see Attachment 1).
Pond Mitigation Site The pond mitigation site is an ephemeral water body in terms of surface ponding, but the springbox on the south side of the Almaden-Calero Canal is perennial given that at least one seep is perennial through the summer. The water budget at the pond site is a balance between inputs from the upslope watershed, direct rainfall, and springbox inflow and losses from percolation through the pond bottom, evapotranspiration, cattle consumption, and excess water being conveyed downstream through the outlet culvert. Springbox inflows, inclusive of seep flow and surface runoff during storm events, are conveyed to the pond site by a 6 inch steel pipe. The capture of seep flow at the springbox is accomplished via a system of natural channels and manmade ditches. The steel pipe drains into two water troughs, with a combined capacity of 800 to 850 gallons, which when full overflow into the pond. The springbox can become clogged with debris and overflow into the canal.
Calero County Park Pond and Wetland H. T. Harvey & Associates 16 Restoration Project MMP April 26, 2016
The cattle rancher generally pumps water from the water troughs at the pond from July through January (depending on the reliability of other water sources within the Park). The amount of pumped water on a daily basis in the summer and fall can vary from 500 to 800 gallons per day. The water troughs are typically refilled over night by the springbox inflow. Cows require 10 to 12 gallons per day (gpd)/head whereas cow/calf pairs require 20 gpd/pair. The cattle rancher can have up to 35 head at any one time.
Per the water budget as described in Section H.2.5 and Attachment 1, Figure 3 shows the existing water level regime in the pond. Under existing conditions, the pond typically dries out by early July in drier water years and by early August in wetter water years that experience significant rainfall in February and March. In wetter years, there is sufficient rainfall to cause the pond to spill multiple times through the outlet culvert.
Figure 3. Pond Mitigation Site Hydrologic Regimes
Calero County Park Pond and Wetland H. T. Harvey & Associates 17 Restoration Project MMP April 26, 2016
Wetland Mitigation Site The wetland mitigation site is a perennial source of water for the cattle rancher. The water budget at the wetland site is a balance between inputs from seep inflow and direct rainfall and losses from percolation under the access road, evapotranspiration, cattle consumption, and excess water being conveyed down the ditch alongside the access road in the winter. The existing plumbing from the springbox (small diameter galvanized pipe) and upper pool (rubber hose) is non-functional. Cattle have direct access to graze and drink at the wetland; the wetland water level recovers relatively quickly after cattle drink at the wetland. The upper pool of the wetland is bounded by a berm and appears to capture the primary seep inflow to the wetland as evident from February 10, 2016 flow measurements (see Section H.2.6) showing that most of the surface flow leaving the wetland was attributed to flow from the upper pool into the lower pool.
H.2.2 Estimated Sources of Hydrology (if different from existing)
This section is not applicable because the project is not establishing new sources of hydrology.
H.2.3 (For streams) Channel Stability
Pond Mitigation Site Surface flow in excess of pond capacity is conveyed through the overflow culvert into an ephemeral drainage immediately downstream of the pond. Overflow from the cantilevered overflow culvert splashes onto a grouted riprap apron, then flows over existing riprap and bedrock downslope of the grouted riprap apron that is not grouted, before entering the upstream limits of the ephemeral drainage. The ephemeral drainage at the base of the riprap and bedrock is bounded by riparian trees on both banks with an extensive root network that has been exposed due to the erosive forces of repeated overflow events; however, the root network is intact and prevents any further bank erosion. As part of the project, the outlet works from the pond (i.e., overflow culvert, grouted riprap apron, ungrouted riprap and bedrock) will be upgraded to manage erosive forces to limit bank erosion thereby protecting existing riparian trees, and to prevent undermining of the pond berm. The small earthen, partially man-made drainage conveying surface flow to the springbox is undersized and has filled with sediment and debris. The project will manually excavate the channel to improve seep flow conveyance to the springbox.
Wetland Mitigation Site Surface flow in excess of wetland capacity is conveyed into a roadside ditch downstream of the wetland. This roadside ditch appears stable.
H.2.4 Description of Historic Changes to Channel Morphology
This section is not applicable because the project is not restoring or impacting a stream channel.
Calero County Park Pond and Wetland H. T. Harvey & Associates 18 Restoration Project MMP April 26, 2016
H.2.5 Surface Hydrology and Hydraulics
A detailed water budget for the pond mitigation site was prepared and is included as Attachment 1. The water budget was calibrated to site conditions for the beginning of Water Year 2016 based on monitoring data described in Section H.2.10. Figure 3 shows the results of the water budget. Under existing conditions, the pond typically dries out by early July in drier water years and by early August in wetter water years that experience significant rainfall in February and March. In wetter years, there is sufficient rainfall to cause the pond to spill multiple times through the outlet culvert. Under project conditions, the hydrologic regime at the pond will be altered to meet project objectives by ponding water to a minimum of two feet deep in the excavated pond bottom through the end of August. Figure 3 also shows the changes to the water level regime when the pond is drained in September for predator control and/or maintenance.
A water budget for the wetland mitigation site was not prepared because preparation of a water budget was not necessary to support preparation of the conceptual wetland mitigation plan and due to the difficulty in accurately estimating or measuring seep inflow and wetland losses. Observations by cbec combined with anecdotal information from the cattle rancher indicate that the wetland site is perennial and is a perennial source of water for cattle ranching operations.
Modeling (attached): ☒
Field gage data (attached): ☒
H.2.6 Direction Observations:
Table 2 below contains manual measurements for flow rates from the pond and wetland mitigation sites to understand the productivity of the seeps contributing to each site. At the pond site, productivity is adequate to meet cattle demands in the fall and early winter, but increases considerably in the winter after significant rainfall. At the wetland site, there is excess seep inflow in the winter that exceeds the capacity of the wetland.
Table 2. Seep Flow Rate Measurements
Date Site Location Flow Rate (gpd) 2/10/2016 Upper Pool 386 Wetland 2/10/2016 Culvert 353 10/27/2016 720 12/4/2015 514 2/10/2016 Large Pipe 2215 2/10/2016 2286 2/26/2016 Pond 2400 10/27/2016 95 12/4/2015 73 Small Pipe 2/10/2016 48 2/26/2016 67
Calero County Park Pond and Wetland H. T. Harvey & Associates 19 Restoration Project MMP April 26, 2016
H.2.7 Location of Site Relative to Hydrologic Sources
Both the pond and wetland mitigation sites are directly connected to their hydrologic sources through natural and/or manmade connections.
H.2.8 Strahler Stream Order
This section is not applicable because the project is not restoring a stream channel.
H.2.9 Connectivity to Other Aquatic Resources
The pond mitigation site is located at the headwaters of an unnamed ephemeral tributary to Alamitos Creek. Overflow and percolation from the pond mitigation site contribute to ephemeral surface flows within this unnamed tributary that supports seasonal wetland and oak-dominated riparian habitat downstream of the pond. Excess water from the wetland is conveyed downstream into an ephemeral earthen roadside ditch.
H.2.10 Sub-surface Hydrologic Monitoring
Water level and rainfall monitoring was performed at the wetland and pond sites. Figure 4 shows the location of the instrumentation. Onset HOBO water level data loggers were installed in the upper pool of the wetland, the bottom of the pond, and at the fringe to the seasonal wetlands in the pond. An Onset HOBO tipping bucket rain gage was co-located with the level logger at the fringe of the seasonal wetlands. These data, along with observations in Section H.2.6, are described in Attachment 1 and were used in the initial calibration of the water budget for the pond site.
Calero County Park Pond and Wetland H. T. Harvey & Associates 20 Restoration Project MMP April 26, 2016
N:\Projects3700\3753-01\Reports\MMP\Figure 4 Hydrology Gage Locations.mxd mchilds Figure Prepared By: Prepared Figure Calero County Pond Park and WetlandRestoration Project (3753-01) Figure 4. Hydrology Gage Locations Gage Hydrology 4. Figure April 2016 April
H.2.11 Attach Data
See Section H.2.10 and Attachment 1 for in-progress water level monitoring data.
H.2.12 Water Budget Depth, Duration, Timing
See Section H.2.1, Section H.2.5, and Attachment 1 for a detailed description of the hydrologic regime for existing and proposed project conditions.
H.3 Soil Characteristics
H.3.1 NRCS Soil Survey Information
The sols in the pond mitigation site are mapped as Alumrock-Zeppelin complex, 9 to 15 percent slopes (NRCS 2015). This series consists of moderately deep and well drained soils that formed in residuum from weathered sandstone and are primarily found on hills. These soils generally consist of sandy loam with fine sandy loam atop layers of sandy clay loam and gravelly clay loam. The soil surface generally contains a layer of slightly decomposed plant material. Clay content in these soils can range from 18 to 45 percent. The soils at the pond mitigation site may be influenced by nearby serpentinite outcrops. Sediment from adjacent slopes has accumulated in the pond bottom.
The soils in the wetland mitigation site are mapped as Montara-Santerhill complex, 15 to 30 percent slopes (NRCS 2015). This series consists of shallow, somewhat excessively drained soils that formed in residuum from weathered serpentinite with components of deep, well drained soils that formed in colluvium from serpentinite and serpentinite rock outcrops. These soils are primarily found on hills. These soils generally consist of sandy loam and clay atop gravelly sandy loam, cobbly sandy loam, and gravelly clay loam. These soils typically exhibit increasing rock fragment content with depth. The soils at the wetland mitigation site are strongly influenced by serpentine bedrock. The wetland mitigation site is in a former quarry and features exposed serpentinite bedrock and sediment that has accumulated in the wetland from an adjacent barren quarry slope.
H.3.2 Soils Tests or Observations Confirm Soil(s) Mapped?
Y: ☒ N: ☐
H.3.3 Soils Fertility Testing, Soil Permeability Testing
A representative soils sample from the pond mitigation site was analyzed for horticultural suitability, fertility, physical characteristics, and infiltration rate. Attachment 2 contains the results of this analysis.
H.3.4 Assessment of Whether Soils are Appropriate for Mitigation Site
Soils at both the pond and wetland mitigation site currently support small populations of the target wetland plant communities. The chemistry of the soils at the pond mitigation site indicate that the soils are moderately
Calero County Park Pond and Wetland H. T. Harvey & Associates 22 Restoration Project MMP April 26, 2016
influenced by serpentine rock; these soils exhibit moderately high metal concentrations (e.g., iron, manganese) and moderately low calcium to magnesium ratio, typical of serpentine influenced soils (Attachment 2). Nonetheless, the metal concentrations, calcium to magnesium ratio, and all other horticultural parameters tested (e.g., pH, boron, electrical conductivity, texture, percent organic matter) are within the range of the target native wetland plants, as evidenced both by the native wetland plants growing on site and our review of horticultural data from other H. T. Harvey & Associates project sites. Conversely, subsoil at the design. Therefore, salvaged pond soils from excavation to deepen the pond will be utilized as topsoil to support habitat functions and wetland plant growth in the pond restoration and wetland establishment areas. Any excess pond soil will be placed in a spoils pile shown as described in Section J.2.
H.3.5 Description of Geology
The wetland and pond mitigation sites are located between the Calero fault and Berrocal fault zone within the Franciscan Complex, Unit 1 (Coastal Ranges). The Franciscan Complex generally consists of Cretaceaous and Jurassic sandstone, and secondarily mudstone, with smaller amounts of shale, chert, limestone, and conglomerates (Jennings et al., 1977). Other rock types include serpentinite as previously described in Section H.2.
H.3.6 Geology Survey Review Attached
Y: ☐ N: ☒
H.3.7 List Any Formations Which May Limit or Expand Mitigation Site
Slips: ☐ Fault Lines: ☐ Seeps: ☒ Landslides: ☐ Other:
H.4 Habitat Characteristics
Pond Mitigation Site Vegetation. The pond mitigation site is a located in rolling hills that are grazed by cattle. Land use surrounding the site is agricultural with a mosaic of grazed grasslands and woodlands. Photos of the site showing pre-project conditions are provided in the wetland delineation in Attachment 3. The following biotic habitats occur at the site, as described by the Habitat Plan land cover types: pond, coastal and valley freshwater marsh, seasonal wetland, Himalayan blackberry (not a Habitat Plan land cover type) California annual grassland, coast live oak woodland and forest, and serpentine brunchgrass grassland (Figure 5). Vegetation in all of these habitat types is heavily grazed by cattle throughout the year, which affects vegetation height, distribution, and composition.
Calero County Park Pond and Wetland H. T. Harvey & Associates 23 Restoration Project MMP April 26, 2016
Pond habitat is open water when inundated and supports minimal vegetation cover when the pond is dry. Coastal and valley freshwater marsh habitat is associated with seeps in an area adjacent to the pond beneath the pipe that conveys water from a springbox and also in seeps upstream of the springbox. Vegetation in the coastal and valley freshwater marsh habitat includes the short statured species including seep monkeyflower (Mimulus guttatus), spreading rush (Juncus patens), sow thistle (Sonchus asper), and a population of Mt. Hamilton thistle. Vegetation in the seasonal wetland habitat includes common spikerush (Eleocharis macrostachya), and spreading rush. Nonnative, invasive Himalayan blackberry (Rubus armeniacus) occurs on the berm. Vegetation in the California annual grassland habitat is dominated by nonnative annual grasses including ripgut brome (Bromus diandrus) and wild oats (Avena fatua) and annual forbs including bur clover (Medicago polymorpha), red stemmed filaree (Erodium cicutarium), and tarweed (Madia sp.). Vegetation in the coast live oak woodland and forest includes an overstory of coast live oak (Quercus agrifolia), California bay laurel (Umbellaria californica), and toyon (Heteromeles arbutifolia) and an understory of poison oak (Toxicodendron diversilobum) and annual grasses. Vegetation in the serpentine bunchgrass grassland includes purple needleegrass (Stipa pulchra), wild hyacinth (Dichelostemma capitatum), California plantain (Plantago erecta), and other native species commonly found on serpentine soils. Historic habitat types at the site were likely similar to existing conditions, although pond habitat was likely absent prior to construction of the berm.
Calero County Park Pond and Wetland H. T. Harvey & Associates 24 Restoration Project MMP April 26, 2016 Legend
Restoration Project Area Photo points Pond (0.22 ac) 5 Coastal and Valley Freshwater Marsh (0.11 ac) Seasonal Wetland (0.21 ac) California Annual Grassland (1.65 ac) Coast Live Oak Woodland and Forest (0.39 ac) 4 Almaden-Calero Canal Himalayan Blackberry (0.02 ac) Serpentine Bunchgrass Grassland (0.28 ac) Drainage Culvert Outlet Pipe and Apron Approximate Location of Mt. Hamilton Thistle Population
7
Pond Drainage Structure 9 3 6 11
B e 8 r m 10 Springbox
100 50 0 100 Springbox Outflow Pipe Feet N:\Projects3700\3753-01\Reports\MMP\Figure 5Pond MitigationSite Existing- Conditions.mxd
Figure 5. Pond Mitigation Site - Existing Conditions Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016
Special-Status Species. Mt. Hamilton thistle is a perennial herb that is classified as a Rank 1B.2 plant (rare, threatened, or endangered in California or elsewhere) by the California Native Plant Society (CNPS 2016). Mt. Hamilton thistle generally occurs in serpentinite seeps in valley and foothill grassland, cismontane woodland, and chaparral habitats. It is threatened by urbanization, nonnative plants, trampling, grazing, and possibly by recreational activities (CNPS 2016). Mt. Hamilton thistle is described as a strict endemic with an affinity to serpentine soil (Safford et al 2005). Mt. Hamilton thistle occurs in the pond mitigation site where it grows in coastal and valley freshwater marsh habitat in the seep area downstream of the springbox outflow pipe (Figure 5). The area where Mt. Hamilton thistle occurs is currently subject to grazing which degrades conditions for the thistle.
There are no current documented observations of the California red-legged frog and California tiger salamander in the pond mitigation site. However, surveys for these species were not conducted prior to the preparation of this MMP. The closest known occurrence of the California red-legged frog to the pond is approximately 1.4 mile to the south in Cherry Creek (California Natural Diversity Database [CNDDB] # 254) (Figure 6). There are no apparent barriers to dispersal between Cherry Creek and the pond mitigation site. Therefore, the California red-legged frog is expected to be able to disperse to the pond from this known occurrence. The closest known occurrence of the California tiger salamander to the pond is approximately 0.24 mile to the northeast in a seasonal pond (CNDDB occurrence # 450). As with the California red-legged frog, there are no apparent barriers to dispersal between this pond and the pond mitigation site. Therefore, the California tiger salamander is expected to be able to disperse to the pond mitigation site from this known occurrence.
Suitable breeding habitat for the California tiger salamander consists of seasonal pools or ponds that hold water for at least 10 weeks (typically into mid or late May in Santa Clara County) and that lack high numbers of aquatic predators such as American bullfrogs (Lithobates catesbeianus), crayfish, and fish. Suitable breeding habitat for the California red-legged frog consists of pools within drainages, or ponds, that hold water through July, provide robust emergent vegetation used for egg mass attachment, and lack high numbers of the aforementioned aquatic predators.
The hydroperiod of the pond mitigation site is currently suitable for California tiger salamander in most years because it ponds into July; its hydroperiod is suitable for California red-legged frog only in very wet years because it dries out in early July during most years. However, the pond does not provide suitable habitat to support successful breeding for either species in its current condition due to several biotic factors. The only emergent vegetation present, spreading rush and common spikerush, is relatively short-statured and flimsy, and occurs only in the shallowest areas around the pond; as a result, this vegetation is unsuitable for egg mass attachment by California red-legged frogs. In addition, nonnative aquatic predators of both the California tiger salamander and California red-legged frog are relatively abundant in the pond under current conditions. The Louisiana red swamp crayfish (Procambarus clarkia) was observed by Will Spangler and H. T. Harvey & Associates wildlife biologist Jeff Wilkinson during a site visit on October 27, 2015. At this time, the pond was dry and several crayfish burrows and carapaces were observed along the bottom of the pond. Approximately 20 adult individuals of the American bullfrog were also observed by H. T. Harvey & Associates wildlife staff at the pond
Calero County Park Pond and Wetland H. T. Harvey & Associates 26 Restoration Project MMP April 26, 2016
mitigation site during March 2016 site visits. This species has also been observed approximately 0.9 mile to the southeast in a pond at the base of the main dam on Calero Reservoir (H. T. Harvey & Associates 2012). Therefore, even if this species was successfully removed from the pond mitigation site, it is expected to be able to disperse to the pond from this or any other nearby source location. Both the Louisiana red swamp crayfish and American bullfrog are known to negatively impact both the California red-legged frog and California tiger salamander (Hayes and Jennings 1986, Shaffer et al. 1993, Lawler et al. 1999).
California ground squirrel (Otospermophilus beecheyi) inhabit the California annual grassland habitat adjacent to the pond. The abundance of ground squirrel burrows in these grasslands provides high-quality upland refugial habitat for the California tiger salamander, and these burrows may provide refugia for the California red-legged frog as well.
Baseline species-specific surveys will be conducted for both the California red-legged frog and California tiger salamander to determine if they are currently inhabiting the pond and/or using the pond for breeding. Presence/absence surveys will be completed in spring 2016.
Three individuals of the western pond turtle were observed in the pond mitigation site during surveys for this species in 2012 (H. T. Harvey & Associates 2012). In addition, one individual was observed by H. T. Harvey & Associates restoration ecologist Will Spangler during a site visit on February 10, 2016, and two individuals were observed by H. T. Harvey & Associates senior wildlife ecologist Steve Rottenborn during a site visit on March 23, 2016. These observations indicate that this species is currently using the pond as foraging habitat.
Calero County Park Pond and Wetland H. T. Harvey & Associates 27 Restoration Project MMP April 26, 2016
Legend
Project Location
2-mile Radius
CNDDB Records Wildlife
Specific Location
Approximate Location
General Area
Source: H. T. Harvey & Associates; CNDDB 2016
CTS CTS
CTS CTS CTS
CTS
CTS CTS
CTS CTS
CTS CRLF
5000 2500 0 5000
Feet Background: Esri Street Base Map N:\Projects3700\3753-01\Reports\MMP\Figure6 CNDDB Occurrences of CRLFand CTS.mxd Figure 6. CNDDB Occurrences of the California Red-Legged Frog and the California Tiger Salamander Near Project Site Calero County Park POnd and Wetland Restoration Project (3753-01) April 2016 Wetland Mitigation Site Vegetation. The wetland mitigation site is located at a former quarry site in rolling hills that are grazed by cattle. Land use surrounding the wetland is agricultural, with a mosaic of grazed grasslands and woodlands. Photos of the site showing pre-project conditions are provided in attached wetland delineation as Attachment 3. The following biotic habitats occur at the site, as described by the Habitat Plan land cover types: coastal and valley freshwater marsh, seasonal wetland, California annual grassland, coffeeberry scrub (not a Habitat Plan land cover type), barren, and serpentine bunchgrass grassland. Vegetation in all of these habitat types is heavily grazed by cattle throughout the year, which affects vegetation height, distribution, and composition. Coastal and valley freshwater marsh habitat is located in the perennially inundated area below the seep and in the lowest elevation portions of the wetland, including an area behind a small berm that was likely constructed to impound water in the wetland. Vegetation in the coastal and valley freshwater marsh habitat includes seep monkeyflower, Baltic rush (Juncus balticus), and Mexican lovegrass (Eragrostis mexicana). Vegetation in the seasonal wetland habitat includes iris leaved rush (Juncus xiphioides) and toad rush (Juncus bufonius). California annual grassland habitat is dominated by nonnative annual grasses including ripgut brome (Bromus diandrus), wild oats, and annual blue grass (Poa annua) and annual forbs including nonnative bur clover (Medicago polymorpha) and native shining peppergrass (Lepidium nitidum). Coffeeberry (Frangula californica), a native perennial shrub or small tree, forms a thicket adjacent to the freshwater marsh and seasonal wetland at the toe of the barren rock slope. Barren habitat is found on a quarried rock slope above the wetland site, and supports minimal vegetation, although approximately 100 individuals of the most beautiful jewelflower (Streptanthus albidus ssp. peramoenus) were detected on these slopes, in the eastern part of the wetland mitigation site, in April 2016. Vegetation in the serpentine bunchgrass grassland includes purple needlegrass (Stipa pulchra), California melic grass (Melica californica), spring beauty (Claytonia exigua), wild hyacinth (Dichelostemma capitatum), California plantain (Plantago erecta), and other native species commonly found on serpentine soils. Historical habitat types at the site were likely similar to existing conditions, although coastal and valley freshwater marsh and seasonal wetland habitat may have been absent prior to excavation of the quarry.
Special-Status Species. The only special-status species known to occur at the wetland mitigation site is the most beautiful jewelflower, which occurs on the steep rocky slopes in the eastern part of the wetland mitigation site. There are no current documented observations of the California red-legged frog and California tiger salamander at the wetland mitigation site. However, surveys for these species were not conducted prior to the preparation of this MMP. The California tiger salamander is not expected to be present in the wetland as it is not considered breeding habitat for this species. The California red-legged frog may use the wetland as foraging, refugial, and dispersal habitat, but it is not expected to breed in the wetland. The closest known occurrence of the California red-legged frog to the wetland is approximately 1.4 mile to the south in Cherry Creek (CNDDB occurrence # 254) (Figure 6). There are no apparent barriers to dispersal between Cherry Creek and the wetland. Therefore, the California red-legged frog is expected to be able to disperse to the wetland from this known occurrence. Species-specific surveys will be conducted for the California red-legged frog to determine if it is currently using the wetland as habitat. Presence/absence surveys will be conducted in spring 2016. The western pond turtle has not been observed at the wetland and invasive wildlife species such as the Louisiana red swamp crayfish and the American bullfrog have not been observed at the wetland. California ground squirrel inhabit
Calero County Park Pond and Wetland H. T. Harvey & Associates 29 Restoration Project MMP April 26, 2016
the serpentine bunchgrass grassland habitat adjacent to the pond and their burrows are present near the wetland. The abundance of ground squirrel burrows around the wetland provide estivation habitat for both the California tiger salamander and California red-legged frog.
Calero County Park Pond and Wetland H. T. Harvey & Associates 30 Restoration Project MMP April 26, 2016
Legend
Restoration Project Area
Photo points
Elevation Contours (1 foot)
Existing Habitat Types Almaden-Calero Canal Coastal and Valley Freshwater Marsh (0.06 ac)
Seasonal Wetland (0.04 ac)
Serpentine Bunchgrass Grassland (0.41 ac)
Coffeeberry Scrub (0.15 ac)
Barren (0.28 ac)
Developed (0.02 ac)
Drainage
1
2
50 25 0 50
Feet N:\Projects3700\3753-01\Reports\MMP\Figure 7Wetland Mitigation Site - ExistingConditions.mxd
Figure 7. Wetland Mitigation Site - Existing Conditions Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016
Section I. Other Baseline Information
I.1 Delineation of Waters of the U.S.
A wetland delineation report has been prepared to delineate the waters of the U.S. (see Attachment 3).
I.2 List of Other Resource Agencies Involved In Approving The Mitigation Plan And Delineation Of Jurisdictional Boundaries (Attach Map)
Permits and/or approvals will be required from the USACE (under Clean Water Act Section 404), CDFW (under California Fish and Game Code Section 1600), and RWQCB (under Clean Water Act Section 401 and Porter-Cologne Water Quality Control Act). In addition, federal Endangered Species Act and California Natural Community Conservation Planning Act compliance will be granted by the Habitat Agency under the Habitat Plan. Additional permits from USFWS or CDFW for listed species impacts are not required. Attachment 4 provides a map of USACE, RWQCB, and CNPS jurisdictional areas.
I.3 California Rapid Assessment Methodology (CRAM) Assessment of Mitigation Site
The project site has not been assessed with the California Rapid Assessment Method (CRAM). CRAM is not proposed as an ecological performance measure because CRAM is relatively insensitive to the proposed changes in ecological conditions at the small scale of this particular restoration project. The functional ecological lift resulting from the restoration project is described in Section J.2.
I.4 Existing and Planned Land Uses Adjacent To Proposed Mitigation Site
The project is composed of two mitigation sites located in Calero County Park. The land use adjacent to the mitigation sites is parkland. Urban-suburban and rural residential development is present in the lower watershed.
I.5 Historic Conditions
Aerial photos: ☒(attached)
The project site is located within former Rancho San Vicente, a 966-acre area that was originally part of a 4,400- acre land grant given to Jose de los Reyes Berryessa in 1842 (Santa Clara County Parks and Recreation Department 2013). These lands have been continuously grazed since the early days of Mexican colonization. A
Calero County Park Pond and Wetland H. T. Harvey & Associates 32 Restoration Project MMP April 26, 2016
berm was constructed at the pond mitigation site to impound water at the pond. Mining of rock and aggregate from the adjacent hillslope occurred at the wetland mitigation site. Rancho San Vicente was purchased by the County from the Peninsula Open Space Trust in 2009. The area is considered part of Calero County Park, but is not yet open to the public. Currently, these lands are leased for grazing to a private operator. Historical aerials are included in Attachment 5.
I.6 Interviews
The current grazing operator at the project site, Lindsey Alpers, was interviewed regarding existing and historical conditions, and current and anticipated cattle water demands at the pond and wetland mitigation site. A summary of this interview is included as Attachment 6.
Calero County Park Pond and Wetland H. T. Harvey & Associates 33 Restoration Project MMP April 26, 2016 Section J. Mitigation Work Plan
J.1 Geographic Boundaries
Construction activities at the pond mitigation site will be limited to the project area boundary shown on Figure 8 and construction activities at the wetland mitigation site will be limited to the project area boundary shown on Figure 11.
J.2 Conceptual Construction Plan and Methods
Pond Mitigation Site Conceptual Construction Plan and Description of the Ecological Functions Restored/Established This section describes the conceptual pond restoration plan, the basis of design for the proposed actions, and the associated improvement in various ecological functions (i.e., ecological lift).
J.2.1 Overview
The pond mitigation site is designed to meet the objectives of restoring breeding habitat for the California red- legged frog and California tiger salamander, restoring wetland habitat functions, establishing new wetland habitat, establishing western pond turtle basking habitat, and continuing to provide water for cattle that graze the surrounding Calero Reserve. These objectives are further described in Section E above. The pond mitigation site has also been designed to result in no net loss of open water and pond habitat and to result in a net gain in wetland habitat. The conceptual plan includes the following actions which are shown in Figure 8 and further described below:
• excavation of a deeper pool to increase the inundation depth and duration to restore California red-legged frog breeding habitat • excavation to convert uplands to new seasonal wetland habitat • installation of fencing to exclude cattle grazing to restore California red-legged frog breeding habitat, wetland habitat, and Mt. Hamilton thistle habitat • installation of a new cattle trough, water tank and springbox pipe diversion system to provide water for both the pond and cattle use (outside of the cattle exclusion area) • installation of a new pond outflow culvert • installation of a new pond low-elevation, outlet drain to fully drain the pond for invasive aquatic predator control • improvement of upstream seep water collection to the springbox to increase seep inflows to the pond • removal of invasive plant species at the pond • installation of native wetland plants
Calero County Park Pond and Wetland H. T. Harvey & Associates 34 Restoration Project MMP April 26, 2016
J.2.2 Pond/Open Water Habitat Restoration
H. T. Harvey & Associates senior herpetologist, Jeff Wilkinson set the following hydroperiod (depth and duration of inundation) design criteria for California red-legged frog breeding habitat at this site: pond habitat inundated by at least three feet of open water through June 31 and at least two feet of open water through August 31 during average rainfall years. The pond currently dries out in early July and does not meet these design criteria (Figure 3). Therefore, the open water portion of the pond will be excavated and lined with bentonite (placed as dry bentonite and covered with salvaged pond soil) to meet the design criteria and restore breeding habitat for the red-legged frog. The pond excavation is designed to provide at least 3 feet of inundation through June to inhibit emergent wetland vegetation colonization of the pond and at least 2 feet of inundation through August to provide sufficient time for California red-legged frog individuals to complete their lifecycle. The deeper pool will substantially increase the volume of open water and pond habitat available to both the red-legged frog and the California tiger salamander and thereby increase the prey base for these species. Anchored basking logs will be installed in the pond to provide basking sites for the western pond turtle at a range of pond depths (Figure 8). A new outlet drain will be installed below the culvert at the bottom of the deeper pool to allow managers to fully drain the pond to control aquatic predators. A flow splitter will be installed on the pipe conveying flow from the springbox to allow managers to divert water to assist in drying out the pond, when necessary to control invasive aquatic predators.
J.2.3 Cattle Exclusion Fencing
The pond mitigation site is a focal point for cattle to forage and drink. Intensive cattle use currently degrades the pond and fringing wetlands by reducing plant height and density, compacting wetland soils, and via inputs of fecal matter. Therefore, cattle exclusion fencing will be installed to protect and restore wetland vegetation in a portion of the pond area and also protect the existing Mt. Hamilton thistle habitat. Container plantings and/or direct transplants of diverse native wetland vegetation will be installed at various elevations in the pond. Cattle exclusion will facilitate the increased growth and recruitment of existing and planted wetland vegetation which will restore various wetland functions including the following: provision of habitat for California red- legged frog habitat (eggs, larvae, and adults), increased height and density of wetland vegetation thereby improving habitat quality for wetland associated wildlife, increased species richness of native wetland vegetation, increased above ground primary production typical of high quality wetlands, and improved filtration of suspended sediments, nutrients, and organic matter thereby improving downstream water quality.
The fencing will be aligned to allow cattle access to a portion of the pond (Figure 8). Partial grazing of the pond mitigation site will limit the extent of dense, tall vegetation along approximately 25% of the pond perimeter and thereby improve California tiger salamander breeding and dispersal habitat. A gate in the fencing will allow managers to flash graze the pond vegetation for long-term adaptive management. The combination of active revegetation, partial cattle exclusion and active grazing will restore a mosaic of high quality wetland and open water habitats.
Calero County Park Pond and Wetland H. T. Harvey & Associates 35 Restoration Project MMP April 26, 2016
J.2.4 Improvements to Springbox-Seep Water Collection System
Improvements to seep water collection will increase the amount of water available for pond/wetland habitat while still providing water for cattle use outside of the fenced area. These improvements will include excavating the existing ditch conveying seep water to the springbox to increase the conveyance capacity of the ditch. Woody debris jams will also be installed to capture sediment prior to the springbox and thereby reduce the potential for sediment to clog the springbox.
J.2.5 Wetland Establishment
Excavation to convert uplands to seasonal wetland habitat will establish a small surface area of new wetland habitat located on the south side of the pond. The concept plan involves lowering existing uplands to elevations comparable to adjacent, existing wetlands fringing the pond to establish the same topography and hydroperiod as these existing wetlands. Grading will make the established wetland contiguous with the existing wetlands. The new wetlands will provide additional wetland habitat functions, where uplands currently exist. These functions will include provision of habitat for California red-legged frog habitat (eggs, larvae, and adults), increased height and density of wetland vegetation thereby improving habitat quality for wetland associated wildlife, increased species richness of native wetland vegetation, increased above ground primary production typical of high quality wetlands, and improved filtration of suspended sediments, nutrients, and organic matter thereby improving downstream water quality.
Calero County Park Pond and Wetland H. T. Harvey & Associates 36 Restoration Project MMP April 26, 2016 Legend Almaden-Calero Canal Restoration Project Area
Cattle Exclusion Fencing and Gate Install Basking Logs Drainage
Spoils Placement Area
Deeper Pool Excavation Area
Cattle Access to Pond Edge Pond (0.22 ac) Remove Himalayan Blackberry Scrub from Berm Restored Coastal and Valley Approximate Location Freshwater Marsh (0.16 ac) of Mt. Hamilton Thistle Site Restored Seasonal Wetland (0.17 ac) No. P4 Population Established Seasonal Wetland (convert Replace Existing Cattle Troughs upland to wetland) (0.01 ac) with 800 Gallon Concrete Trough *Site No.'s correspond to Table 1A Mitigation Site Description along Fence for Permittee-Responsible Mitigation in the INS
Replace Culvert Outflow Springbox Site Springbox Pipe and Apron with New No. P1 Outflow Pipe Outlet and Drain System
Decommission Site Existing Pond No. P4 Site No. P3 Drain Structure Excavate Existing Drainage Ditch to Convey Seep Site No. P2 Flow to Springbox Berm
Install Woody Debris Jam to Collect Sediment
100 50 0 100
Install 3000 Install Flow Splitter for Feet Gallon Water Tank Seep Diversion to Tank N:\Projects3700\3753-01\Reports\MMP\Figure 8Pond Mitigtation Site- Conceptual Plan.mxd
Figure 8. Pond Mitigation Site - Conceptual Plan Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016 J.3 Pond Mitigation Site Conceptual Construction Methods
J.3.1 Temporary Dewatering Methods
The pond will be dewatered to facilitate construction. Dewatering will occur in August, when the pond is expected to be dry with the exception of a low inflow rate of seep water from the springbox. Therefore, the pond will be dewatered by rerouting the pond inflow from the springbox to a temporary water tank and conveying any excess water to the creek downstream of the pond, in a manner that does not cause erosion. The temporary water tank will provide water for cattle during construction. Measures will be taken to ensure that dewatering does not negatively impact Mt. Hamilton thistle population that occurs in the wetlands just downstream of the springbox inflow. The thistle population will be periodically monitored by a qualified biologist during construction and manually, watered, if needed to avoid impacts. If ponded water is present in the pond, this water will be pumped into the temporary water tank, for silts to settle. Prior to dewatering, a qualified biologist will conduct a pre-construction survey for amphibians to ensure that California red-legged frog and California tiger salamander larvae are absent from any ponded areas prior to dewatering. Moreover, if native amphibian adults are present, an effort will be made by the monitoring biologist to capture and relocate these individuals, to the extent feasible.
J.3.2 Summary of Construction Methods
The deeper pool of approximately 8,300 square feet will be excavated in the bottom of the pond and excavation will depths will range from 3 to 5 feet (Figure 9). Side slopes of the deeper pool will range from 1 foot vertical for every 1 foot horizontal to 1 foot vertical for every 3 feet horizontal. The excavated pond bottom will slope to drain to a new outlet structure, shown in Figure 10. Additional seasonal wetland habitat will be established at the south end of the pond by excavating up to 6 feet into the existing ground slope. Side slopes of the wetland establishment area will be 1 foot vertical for every 1 foot horizontal, except on the southern portion, where they will be 1 foot vertical for every 2 feet horizontal. Imported bentonite 3 inches thick will be used to seal the deeper pool and wetland establishment area to reduce percolation losses. The bentonite layer will be covered with 6 inches of soil on the pond bottom and 6-12 inches of soil on the pond slopes and within the wetland establishment area and slopes. The soil cover will be salvaged from excavation of the deeper pool and reused to cover and protect the bentonite layer from desiccation and cracking. Excess excavated material will be placed in a spoils pile shown in Figure 9. Sides of the spoil pile will be sloped no steeper than 3 feet horizontal to 1 foot vertical to create a stable, non-erosive and aesthetic transition onto existing ground. Mechanized equipment will be used to excavate the pond and grade the spoils pile.
A new pond outlet and water control structure (Figure 10) will be installed to replace the existing corroded, corrugated metal culvert and the existing low flow outlet that is buried and no longer functional. The new culvert will be 24-inch High Density Polyethylene (HDPE) pipe. The water control structure will consist of a concrete structure, a canal gate at the base to allow drainage of the entire pond, and an outlet connection to the new 24-inch HDPE culvert. The water control structure will be installed on top of a bedding layer of crushed rock 8 inches to 12 inches thick and 1 feet wider in all dimensions than the base of the structure itself; which
Calero County Park Pond and Wetland H. T. Harvey & Associates 38 Restoration Project MMP April 26, 2016 is approximately 3 feet wide by 4 feet wide on the downstream face. Existing concrete on the upstream face of the berm will be removed. An existing concrete apron on the downstream face of the berm will also be removed and rebuilt, along with a riprap energy dissipater. Recompaction of berm soils around the culvert may include the incorporation of engineered fill soil as necessary.
Mechanized equipment will be used to remove the old pond outlet culvert, install the new outlet culvert, excavate and compact the berm, and install the outlet control structure. Berm cuts will likely be made with an excavator sitting in the pond because the berm is too narrow for equipment access.
Minor improvements will be made to the natural drainages and manmade ditches on the hillside south of the pond on the opposite side of the Almaden-Calero Canal. The purpose of these improvements is to increase the inflow of seep water to the existing springbox and ultimately to the pond. A non-jurisdictional manmade ditch will be hand-excavated to improve capture and conveyance of hillside seep flows to the springbox. The cross section of the improved ditch will include a 2 feet bottom width and 1:1 side slopes. A natural drainage also supplies seep water to the springbox. Steeper portions of the natural drainage will be modified to reduce flow velocities and associated erosion. Wood jams and local rock will be installed as grade control and energy dissipaters to assist in trapping sediment and debris before it enters the springbox to help reduce the need for sediment removal at the springbox. Work in this area will all be accomplished with manual labor.
Plumbing modifications and infrastructure additions will be made to improve management of seep water from the springbox. The 2-inch steel pipe at the springbox will be permanently plugged. A 6 inch 3-way ball valve will be installed on the end of the existing 6 inch outlet pipe from the springbox to divert seep flows either to cattle water troughs, or to a 3,000-gallon composite tank during annual pond dewatering operations. Two 400- gallon cattle water troughs connected by HDPE pipe at the bottom of the troughs will provide 800 gallons of storage capacity for cattle water. One 400 gallon trough will be installed at the end of the 6 inch outlet pipe, under the pipe, and will have an overflow feature to provide excess seep water to the pond. The second 400 gallon trough will be installed at the same elevation to the north, outside a new fence so that cattle can access it. The full 800 gallons of storage provided by the two connected troughs will be pumped from the two connected 400-gallon troughs as needed for cattle operations. The 3,000-gallon composite tank will be installed on the spoils pile outside the pond area (Figure 6). The pipe from the outlet pipe to the 3,000 gallon composite tank will be buried. Plumbing work will be accomplished with manual labor.
Cattle exclusion fencing will consist of "no-climb" field fence mounted on hand-driven T-posts. Corners and gate locations will be installed in poured concrete in a pre-drilled hole.
Calero County Park Pond and Wetland H. T. Harvey & Associates 39 Restoration Project MMP April 26, 2016 EXCAVATION
0 80 160 240 FT
POND EXCAVATION Service Layer Credits: 1" = 80' N:\Projects3700\3753-01\Reports\MMP\Figure 9Pond MitigationSite - Conceptual Pond Grading andHydrologic Infrastructure Improvement Plan.mxd mchilds Figure Prepared By: Figure 9. Pond Mitigation Site - Conceptual Pond Grading and Hydrologic Infrastructure Improvement Plan Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016 Service Layer Credits: N:\Projects3700\3753-01\Reports\MMP\Figure 10 Pond Mitigation Site - OutletWorks Typical Detail.mxd mchilds
Figure Prepared by: Figure 10. Pond Mitigation Site - Outlet Works Typical Detail Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016 J.4 Wetland Mitigation Site Conceptual Construction Plan
This section describes the conceptual wetland restoration plan, the basis of design for the proposed actions, and the associated improvement in various ecological functions (i.e., ecological lift).
J.4.1 Overview
The wetland mitigation site is designed to meet the project objectives of restoring wetland habitat functions, restoring California red-legged frog foraging and dispersal habitat, establishing wetland habitat, and continuing to provide water for cattle that graze the surrounding Calero Reserve. These objectives are further described in Section E above. The construction methods designed to achieve these objectives are shown in Figure 11 and will include the following:
• installation of fencing to exclude cattle grazing • installation of a new trough to provide water for cattle outside of the wetland • excavation to convert adjacent uplands to seasonal wetland habitat • excavation to remove sediment from the wetland • installation of a wetland water level control structure • installation of native wetland plants
J.4.2 Cattle Exclusion Fencing
The wetland mitigation site is a focal point for cattle to forage and drink. Intensive cattle use currently degrades the existing wetlands by reducing plant height and density, compacting wetland soils, and via inputs of fecal matter. Therefore, cattle exclusion fencing will be installed to protect and restore wetland vegetation. Container plantings and/or direct transplants of diverse native wetland vegetation will be installed throughout the wetland mitigation site. Cattle exclusion will facilitate increased growth and recruitment of existing and planted wetland vegetation which will restore various wetland functions including the following: provision of foraging and dispersal habitat for California red-legged frog, increased height and density of wetland vegetation thereby improving habitat quality for wetland associated wildlife, increased above ground primary production typical of high quality wetlands, and improved filtration of suspended sediments and organic matter thereby improving downstream water quality. A gate in the fencing will allow managers to flash graze the wetland vegetation for long term adaptive management.
J.4.3 Deeper Pool Excavation
Excavation to remove sediment will increase the depth of inundation in a part of the wetland to create more heterogeneous wetland conditions. This will improve foraging and dispersal habitat for the California red-legged frog and provide deeper water refugia from predators. Deeper pool excavation will also restore additional breeding habitat for common native amphibians.
Calero County Park Pond and Wetland H. T. Harvey & Associates 42 Restoration Project MMP April 26, 2016 J.4.4 New Outlet Structure
An outlet structure will be installed in the existing ephemeral drainage immediately downstream of the Calero wetland to regulate outflow and increase the water level in the wetland. The outlet structure will consist of a concrete structure with a means for controlling water surface elevation in the wetland (e.g., flashboards) and a dual outlet to direct water to the existing ephemeral drainage downstream of the outlet structure and to a new small diameter, water pipeline to the off-wetland cattle trough. The outlet control structure will allow managers to adaptively raise the wetlands water surface 0.25 feet above the existing condition to improve wetland habitat conditions. The increased depth of inundation will increase habitat quality within the wetland mitigation site by the increasing the density of native wetland vegetation relative to non-native wetland vegetation. The outlet structure will also continue to convey excess water in the rainy season downstream of the wetland to ensure that the downstream ephemeral drainage ditch is not dewatered. The outlet structure will also enable managers to regulate the amount of flow to the cattle trough to ensure that the wetland’s hydrology is maintained to meet the habitat goals and success criteria.
J.4.5 Wetland Establishment
Excavation to convert uplands to seasonal wetland habitat will establish wetland habitat with multiple wetland functions. The concept plan involves lowering existing uplands to elevations comparable to adjacent, existing wetlands to establish the same topography and hydroperiod as these existing wetlands. Grading will make the established wetland contiguous with the existing wetlands. The new wetlands will provide additional wetland habitat functions, where uplands currently exist. These functions will include provision of foraging and dispersal habitat for California red-legged frog, increased height and density of wetland vegetation thereby improving habitat quality for wetland associated wildlife, increased species richness of native wetland vegetation, increased above ground primary production typical of high quality wetlands, and improved filtration of suspended sediments, nutrients, and organic matter thereby improving downstream water quality.
Calero County Park Pond and Wetland H. T. Harvey & Associates 43 Restoration Project MMP April 26, 2016 Legend
Restoration Project Area
Cattle Exclusion Fencing
Drainage
Restored Coastal and Valley Freshwater Marsh Almaden-Calero Canal (0.06 ac)
Restored Seasonal Wetland (0.04 ac) Install Pipe from Outlet to Cattle Trough. Established Seasonal Over Flow to Remain in Drainage Ditch Wetland (convert upland to wetland) (0.02 ac) *Site No.'s correspond to Table 1B Mitigation Site Description for Permittee-Responsible Mitigation in the INS Install Cattle Trough
Install Outlet to Control Water Level
Cattle Exclusion Site No. Fencing Gate W2
Site No. W3
Site No. W1 Site No. W1 Site No. W2
Sediment Removal and Deeper Pool Excavation Area
50 25 0 50
Feet N:\Projects3700\3753-01\Reports\MMP\FigureWetland 11 Mitigation Site - Conceptual Plan.mxd
Figure 11. Wetland Mitigation Site - Conceptual Plan Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016 J.5 Wetland Mitigation Site Conceptual Construction Methods
J.5.1 Temporary Dewatering Plan
At the wetland mitigation site, aquatic resources immediately downstream of the wetland are largely dry in the summer as the wetland is not at capacity and therefore not spilling into the ditch. During construction, the lower and upper pools of the wetland will be dewatered to accommodate grading activities. The water will be pumped into a temporary offline water tank to serve the dual purpose for cattle consumption as well as refilling the wetland after grading and revegetation activities. During construction, if the tank becomes full, and to prevent overflow into downstream aquatic resources that are normally dry during the summer, the rancher will pump from the tank for cattle use. Prior to dewatering, a qualified biologist will conduct a pre-construction survey for amphibians. Larvae of native amphibian species are not expected to occur because the wetland does not provide suitable breeding habitat for California red-legged frog or tiger salamander and other native amphibians will complete their life cycle prior to dewatering in August. However, if native amphibian adults are present at the time of the pre-construction survey, an effort will be made by the monitoring biologist to capture and relocate these individuals, to the extent feasible.
J.5.2 Summary of Construction Methods
Additional seasonal wetland habitat will be established on the east and west ends of the wetland by excavating approximately 6 inches to 2 feet of sediment and upland soil (Figure 12). Imported bentonite 3 inches thick will be used to seal the wetland establishment area to reduce percolation losses. The bentonite layer will be covered with 6-12 inches of soil within the wetland establishment area and slopes. The soil cover will be salvaged from excavation of the deeper pool at the pond mitigation site and reused to cover and protect the bentonite layer from desiccation and cracking. In the upper wetland, soft sediments over an area of approximately 400 square feet will be excavated to a depth of up to 2 feet, or rock refusal. This area will not be backfilled with clay or soil. Side slopes of all excavations and clay and soil fills will be maintained at 1 foot vertical for every 1 foot horizontal, if possible. Excess excavated material will be transferred to the spoils pile southwest of the pond, described above and shown in Figure 8. Excavation in the wetland area will be performed using mechanized equipment.
A new wetland outlet and water control structure will be installed on the east end of the wetland area at the top of the drainage ditch to regulate outflow and increase the water level in the wetland. The water control structure will consist of a concrete structure with a means for controlling water surface elevation in the wetland (e.g., flashboards) and a dual outlet to direct water to the existing ephemeral drainage ditch downstream of the outlet structure, and to a new, small diameter water pipeline. The outlet control structure will allow managers to adaptively raise the wetlands water surface 0.25ft above the existing condition to improve wetland habitat conditions. The outlet structure will also continue to convey excess water in the rainy season downstream of the wetland to ensure that the downstream ephemeral drainage ditch is not dewatered. The outlet structure will also enable managers to regulate the amount of flow to the cattle trough to ensure that the wetland’s hydrology is maintained to meet the habitat goals and success criteria.
Calero County Park Pond and Wetland H. T. Harvey & Associates 45 Restoration Project MMP April 26, 2016 The water control structure will be installed on top of a bedding layer of crushed rock 8 inches to 12 inches thick and 1 foot wider in all dimensions than the base of the structure itself. The rock may be mixed with bentonite on the upstream side of the outlet to reduce seepage. The water pipeline from the outlet structure will direct water to a new concrete trough, located to the east of the wetland area. Plumbing work will be accomplished with manual labor.
Cattle exclusion fencing will consist of "no-climb" field fence mounted on hand-driven T-posts. Corners and gate locations will be installed in a pre-drilled hole with a poured concrete foundation.
Calero County Park Pond and Wetland H. T. Harvey & Associates 46 Restoration Project MMP April 26, 2016 POND EXCAVATION
Service Layer Credits: N:\Projects3700\3753-01\Reports\MMP\Figure 12 WetlandMitigation Site - Conceptual Grading Plan.mxdmchilds
Figure Prepared by: Figure 12. Wetland Mitigation Site - Conceptual Grading Plan Calero County Park Pond and Wetland Restoration Project (3753-01) April 2016 J.6 Timing (Implementation Schedule)
Construction will likely occur in 2016 during the dry season between July 15 and October 15. Planting will likely occur in 2016 during the early portion of the rainy season (October 15 –December 31). Project construction is expected to begin in summer/fall 2016, however, the project could also be implemented in summer/fall 2017.
J.7 Sequence of Construction
The sequence of construction will be as follows:
1. Contract with a qualified native plant nursery that will provide plants and seed from local propagules
2. Conduct pre-construction surveys for sensitive wildlife species (e.g., nesting birds, native amphibians) 3. Temporarily dewater pond and wetland prior to construction to control aquatic predators and prepare soils for excavation, including provision of the temporary water source for cattle. 4. Install temporary cattle exclusion fencing to exclude from entire construction area 5. Stage equipment 6. Install flagging or environmentally sensitive area (ESA) fencing to protect existing vegetation and special status plant populations. 7. Install erosion and sediment control BMPs. 8. Clear and grub excavation areas, including removal of invasive Himalayan blackberry from pond berm. 9. Excavate deeper pools and wetland establishment areas, followed by installation of bentonite clay liner and soil cover top dressing on wetland and pond areas. Excavate ditch to springbox. 10. Place excavated soils in the spoils pile area. 11. Install basking logs in deeper pool and install grade control (woody debris jams) in drainage to springbox
12. Install water control infrastructure and water troughs. 13. Removal of invasive plant species (Himalayan blackberry) from the pond site 14. Install permanent cattle fencing 15. Apply native seed mix and erosion control fabric or straw to temporarily disturbed areas 16. Install wetland container plants 17. Remove temporary cattle exclusion fencing and construction erosion and sediment control BMPs 18. Conduct as-built topographic cross-section survey and prepare biological as-built report for regulatory agency submittal
Calero County Park Pond and Wetland H. T. Harvey & Associates 48 Restoration Project MMP April 26, 2016 J.8 Impacts
Project construction will result in primarily temporary impacts to pond and open water habitat, coastal and valley freshwater marsh habitat, seasonal wetland habitat, and drainage ditches. These habitats are within the jurisdiction of USACE, RWQCB, and CDFW. The project will also result in temporary impacts to critical habitat of the California tiger salamander. The acreage and linear feet of temporary impacts are shown in Table 3.
Table 3. Project Impacts
Pond Mitigation Site Impacts Temporary Permanent Water Body Type Area (sq. ft.) Length (ft.) Area (sq. ft.) Length (ft.) Pond 7466 N/A 61 N/A Coastal and Valley N/A N/A N/A N/A Freshwater Marsh Seasonal Wetland 321 N/A N/A N/A Drainage 1205 100 16 2 Total: 8992 100 77 2 Pond Mitigation Site Fill and Dredge Quantities Volume Discharged (cubic Volume Dredged (cubic Fill Type Dredge Type yards) yards)
Concrete 1 CY concrete outlet Concrete 0.6 CY structure apron. 3.5 CY concrete outlet structure. Machine placement. Soil/Dirt 186 CY salvaged soil from Soil/Dirt 740.5 pond excavation placed back in pond to cover bentonite. Machine placement. Other: 66 CY imported bentonite. Other: N/A Machine placement. Other: 2 CY imported crushed rock Other: N/A base for outlet structure and apron. Machine placement. Other N/A Other: 25 CY soil excavated by hand from seep collection ditch. Other: 3.6 CY local rocks and wood N/A – grade control in seep collection drainage. Hand placement. Other: 5.5 CY riprap at pond outlet Total: N/A
Calero County Park Pond and Wetland H. T. Harvey & Associates 49 Restoration Project MMP April 26, 2016 Other: 3 CY filter rock (under riprap) at pond outlet Other: 2.5 CY concrete channel lining at pond outlet Total: 267.1 Total: 768.6 Wetland Mitigation Site Impacts Temporary Permanent Water Body Type Area (sq. ft.) Length (ft.) Area (sq. ft.) Length (ft.) Pond N/A N/A N/A N/A Coastal and Valley 636 N/A N/A N/A Freshwater Marsh Seasonal Wetland 346 N/A N/A N/A Drainage 39 9 16 4 Total: 1021 9 16 4 Wetland Mitigation Site Dill and Dredge Quantities Volume Discharged (cubic Volume Dredged (cubic Fill Type Dredge Type yards) yards) River rock N/A River rock N/A Concrete N/A Concrete N/A Structure 1 CY precast concrete weir Structure N/A box. Machine placement. Soil/Dirt 18 CY soil from pond Soil/Dirt 100 CY excavation placed back in pond to cover bentonite. Machine placement. Other: 5 CY imported bentonite. Other: N/A Machine placement. Other: 1 CY imported crushed rock Other: N/A base. Machine placement. Total: 25 Total: 100
Temporary pond and wetland impacts will be due primary to heavy equipment access for excavation to restore the deeper pool and drainage infrastructure at the pond mitigation and to establish new wetlands and remove sediment from the deeper pool at the wetland mitigation site. Heavy equipment will crush wetland vegetation and compact wetland and pond soils to access excavation areas. These impacts are considered temporary because the existing physical conditions (topography and level of soil compaction) will be restored prior to completion of construction, temporary impact areas will be revegetated with native wetland plants, and wetland vegetation and pond habitat is expected to rapidly re-establish in one growing season. Construction will also occur when the pond is dry to minimize impacts to aquatic and wetland habitats. The project will improve the hydrologic regime at the pond and wetland mitigation sites which will contribute to the rapid regeneration and establishment of aquatic and wetland habitats. Surveys for special status species will be conducted during the appropriate season prior to construction and any identified populations will be protected during construction.
Calero County Park Pond and Wetland H. T. Harvey & Associates 50 Restoration Project MMP April 26, 2016 Placement of salvaged pond sediments as cover over the bentonite layer along the deepened pond bottom will also result in temporary impacts to the pond. This fill is considered a temporary impact because the finish grade is below the ordinary high water mark of the pond and the ecological functions of the salvaged pond sediment cover will be the same manner as the previous pond bottom sediments. Impacts to the jurisdictional drainage to the springbox will be temporary because woody debris jams will be installed by hand and will improve drainage geomorphic stability and sediment filtration functions during the first rainy season.
Replacement of existing pond infrastructure will result in a very small surface area of permanent impacts from the installation of concrete, rip rap, and/or gravel on the pond bottom and in the channel immediately downstream of the culvert outlet. However, the footprint of these impacts will be similar to footprint of existing infrastructure to be removed from the pond. Installation of the concrete outlet to control the water level in the wetland mitigation site will result in a very small permanent impact to a jurisdictional ephemeral ditch. These infrastructure items are designed to improve pond and wetland functions and to have a minimal impact on jurisdictional habitats.
J.9 Sources of Water, Connections to Existing Aquatic Resources
At the pond mitigation site, downstream aquatic resources, in the unnamed tributary, rely on a combination of percolation losses from the pond and inflow from seeps downstream of the pond during the summer, and spills from the pond in excess of capacity during the winter. The relative contribution of percolation losses and inflow from seeps downstream of the pond is unknown. Post construction, and per the water budget (see Attachment 1), percolation losses from the pond will be reduced by approximately one third and distributed over October through the end of August versus October through early-July when the pond currently dries out. The unnamed tributary downstream of the pond is an ephemeral drainage supporting seasonal wetland habitat and drought tolerant (coast live oak-dominated) riparian habitat. Therefore, this reduction in pond percolation daylighting as surface flow in the creek immediately downstream of the pond is not expected to dewater downstream aquatic resources. At the wetland mitigation site, aquatic resources immediately downstream of the wetland are largely dry in the summer as the wetland is not at capacity and therefore not spilling into the ditch.
J.10 Plant Species List
J.10.1 Pond Mitigation Site
The pond mitigation site’s wetland plant palette contains a mix of short emergent wetland species and drought tolerant wetland species to provide a range of species that will provide cover throughout the year as the depth of inundation and soil saturation vary. The plant palette was also developed to increase plant species richness at the site. Table 4 provides the plant species palette, relative composition, quantity, on-center spacing, and container type for container plants at the pond mitigation site. The plant palette is based on the species found at the site and in similar habitats in Santa Clara County. The on-center spacing is relatively dense (short distances between plantings) to facilitate rapid establishment of wetland vegetation and thereby increase the resistance of the site to erosion or weed invasion.
Calero County Park Pond and Wetland H. T. Harvey & Associates 51 Restoration Project MMP April 26, 2016 Table 4. Pond Mitigation site - Wetland Plant Species Palette
Common Name1 Scientific Name1 Percent On-Center Quantity Suggested Composition Spacing (ft) Container Type Coast and Valley Freshwater Marsh Planting Zone (short statured emergent wetland plants)
Coast carex Carex obnupta or C. 25 3 27 1 Gallon nudata Needle spikerush Eleocharis 25 3 27 D-40 macrostachya or E. montevidensis Panicled bulrush Scirpus microcarpus 25 3 27 1 Gallon Broadfruit bur reed Sparganium 25 3 27 1 Gallon eurycarpum Seasonal Wetland Planting Zone (drought tolerant seasonal wetland plants)
Clustered field sedge Carex praegracilis 16.6 3 60 D-16 Needle spikerush Eleocharis 16.6 3 60 D-40 macrostachya Beardless wildrye Elymus triticoides 16.6 3 60 D-40 Rush Juncus effusus, J. 16.6 3 60 D-40 balticus, and/or J. mexicanus Spreading rush Juncus patens 16.6 3 60 D-16 Iris leaved rush Juncus xiphioides 16.6 3 60 D-40 1 Names derived from the Jepson Manual, Second Edition (Baldwin et al. 2012). Note that species palette and quantities are conceptual and subject to revision based upon nursery availability. Plant palette revisions, it any, will be consistent with the restoration objectives. Plants may also be transplanted as bare root divisions directly from source populations harvested at the time of construction.
J.10.2 Wetland Mitigation Site
The wetland mitigation site plant palette contains a mix of short emergent wetland species and drought tolerant wetland species to provide a range of species that will provide cover throughout the year as the depth of inundation and soil saturation vary. The plant palette was also developed to increase plant species richness at the site. Table 5 provides the plant species palette, relative composition, quantity, on-center spacing, and container type for container plants at the wetland mitigation site. The plant palette is based on the species found at the site and in similar habitats in Santa Clara County. The on-center spacing is relatively dense (short distances between plantings) to facilitate rapid establishment of wetland vegetation and thereby increase the resistance of the site to erosion or weed invasion.
Calero County Park Pond and Wetland H. T. Harvey & Associates 52 Restoration Project MMP April 26, 2016 Table 5. Wetland Mitigation site - Wetland Plant Species Palette
Common Name1 Scientific Name1 Percent On-Center Quantity Suggested Composition Spacing Container (feet) Type2 Coast and Valley Freshwater Marsh Planting Zone (short statured emergent wetland plants) Coast carex Carex obnupta or C. 25 3 35 1 Gallon nudata Needle spikerush Eleocharis macrostachya 25 3 35 D-40 or E. montevidensis Panicled bulrush Scirpus microcarpus 25 3 35 1 Gallon Broadfruit bur reed Sparganium eurycarpum 25 3 35 1 Gallon Seasonal Wetland Planting Zone (drought tolerant seasonal wetland plants) Clustered field Carex praegracilis 16.6 3 26 D-16 sedge Needle spikerush Eleocharis macrostachya 16.6 3 26 D-40 Beardless wildrye Elymus triticoides 16.6 3 26 D-40 rush Juncus effusus, J. balticus, 16.6 3 26 D-40 and/or J. mexicanus Spreading rush Juncus patens 16.6 3 26 D-16 Iris leaved rush Juncus xiphioides 16.6 3 26 D-40 1 Names derived from the Jepson Manual, Second Edition (Baldwin et al. 2012). Note that species palette and quantities are conceptual and subject to revision based upon nursery availability. Plant palette revisions, it any, will be consistent with the restoration objectives. Plants may also be transplanted as bare root divisions directly from source populations harvested at the time of construction.
J.10.3 Erosion Control Seed Mix for Pond and Wetland Mitigation Sites
A seed mix of native herbaceous species will be applied to all temporarily disturbed areas following construction to reduce soil erosion and to reduce competitive pressure by nonnative herbaceous species. Table 6 provides the native seed mix that will be applied.
Calero County Park Pond and Wetland H. T. Harvey & Associates 53 Restoration Project MMP April 26, 2016 Table 6. Sitewide Erosion Control Seeding Mix
Common Name1 Scientific Name1 Application Rate (pounds PLS/1000 square feet) 2 Blue wild rye Elymus glaucus 0.3 California poppy Eschscholzia californica 0.02 Six weeks grass Festuca microstachys 0.1 Meadow barley Hordeum brachyantherum 0.3 California plantain Plantago erecta 0.02 Blue eyed grass Sisyrinchium bellum 0.02 Purple needlegrass Stipa pulchra 0.1 TOTAL 0.86
1 Names derived from the Jepson Manual, Second Edition (Baldwin et al. 2012). 2 PLS (pure live seed) = the proportion of total seed that is pure and viable. To find the total weight of raw seed needed to achieve the application rate in the table, find %PLS as follows: [(% purity of seed lot) (% germination rate of species)/100]. Then, divide the application rate in the table (pounds) by the %PLS (expressed as a decimal) to find total weight of raw seed applied per acre for each species.
J.10.4 Mt. Hamilton Thistle Seed
Mt. Hamilton thistle seed may be applied at the wetland mitigation site as a voluntary enhancement measure to attempt to establish a population at this site. Seed will be collected from populations growing within the Alamitos Creek watershed in similar ecological conditions as the wetland mitigation site. The application rate will depend on the quantity of seed collected.
Table 7. Mt. Hamilton Thistle Seed Mix
Common Name1 Scientific Name1 Approximate Application Rate (pounds/1000 square feet) Mt. Hamilton thistle Cirsium fontinale var. campylon 0.02 TOTAL 0.02
J.11 Source of Seeds/Plants
All propagules (seeds, divisions, or cuttings) will be collected from Santa Clara County to ensure that the plant material is adapted to the climatic conditions of the project site. Plant propagules will be derived from as close to the site as feasible from locations with similar hydrology and soils. If adequate propagules are unavailable from Santa Clara County, then they will originate from neighboring San Francisco Bay Area counties that exhibit similar environmental conditions to those found at the site. A nursery contract will be established in sufficient time to collect propagules and ensure they have enough growing time as container stock in the nursery before they are installed at the site. Bare root divisions may also be collected for use as direct transplants to supplement nursery container stock; these root divisions will be collected from as close to the site as feasible, irrigated while in storage and stored for no longer than 48 hours, and directly transplanted into the designated planting areas.
Calero County Park Pond and Wetland H. T. Harvey & Associates 54 Restoration Project MMP April 26, 2016 J.12 Planting Methods
J.12.1 Wetland Plantings at the Pond and Wetland Mitigation Sites
Container stock and/or direct transplants of wetland plants will be installed to supplement existing vegetation in areas designed to support wetland vegetation. Short statured emergent wetland species will be installed in the planting zone mapped as coast and valley freshwater marsh on Figures 8 and 11, where inundation is expected to be of greater depth and longer duration. Drought tolerant seasonal wetland species will be installed in the planting zone mapped as seasonal wetland on Figure 8 and 11, where inundation and soil saturation is expected to be of lesser depth and shorter duration, such as around the elevation of the maximum water level.
Plantings will be densely installed within each planting zone at each site. It is assumed that there is existing cover of wetland vegetation in approximately 25% of the coast and valley freshwater marsh planting zone and in approximately 50% of the seasonal wetland planting zone at the pond mitigation site and that there is existing cover of wetland vegetation in 50% of the coast and valley freshwater marsh planting zone and in 25% of the seasonal wetland planting zone at the wetland mitigation site. Plantings will be field fit at the time of installation into areas without existing wetland vegetation cover in the planting zones. Plantings will not be installed in the vicinity of the Mt. Hamilton thistle population to reduce competition with Mt. Hamilton thistle individuals.
The pond mitigation site has been designed to provide a mosaic of vegetated wetland and open water habitats to enhance overall habitat for the California red-legged frog and California tiger salamander. The design includes areas that will be minimally vegetated to provide open water and bare ground to protect California tiger salamander, and are mapped as pond in Figure 8. These areas are designed to have sufficient inundation and cattle grazing access to limit vegetation establishment, and plantings will not be installed in these areas.
Container plantings and/or direct transplants will be installed between October and December when rainfall has saturated the soils. Excavated planting holes will be 2 times the width and equal to the depth of the root volume of the planting. Planting holes will be backfilled with site soil. All plantings will be irrigated immediately following installation, yet will not require supplemental irrigation beyond the initial watering-in. Plantings will be installed so that their root crowns are at grade following soil settlement after irrigation.
J.12.2 Sitewide Erosion Control Seed Mix
Grading and construction access will disturb vegetation and topsoil at the pond mitigation site and the wetland mitigation site. Following construction, a native seed mix will be applied to all temporarily disturbed, upland areas to reduce soil erosion and to reduce competitive pressure by nonnative herbaceous species. The native seed mix will be manually broadcast onto the prepared soil surface. Broadcast seeding will be followed by light raking to a depth of ¼ inch to maximize seed to soil contact. Seed will be applied followed by the installation of biodegradable erosion control fabric (e.g, jute or similar). In areas where seed is applied without fabric, weed-free straw mulch will be applied following seed application.
Calero County Park Pond and Wetland H. T. Harvey & Associates 55 Restoration Project MMP April 26, 2016 J.12.3 Mt. Hamilton Thistle Seed
It is anticipated that the project will establish suitable habitat for the Mt. Hamilton thistle at the wetland mitigation site. Therefore, Mt. Hamilton thistle seed may be installed at the site. Seed will be collected from nearby populations within Santa Clara County (such as the population at the pond mitigation site) by bagging mature individuals and collecting seeds as they disperse. No more than 10% of the seeds of any individual plant will be collected. Seed will be collected between June and August and will be applied to the wetland mitigation site between October and December. Seed collection and application may be necessary in multiple years to ensure an adequate quantity of seed is obtained. Mt. Hamilton thistle seed will be broadcast into the coastal and valley freshwater marsh planting zone (where soils are expected to be saturated for a longer duration) at the wetland mitigation site. Broadcast seeding will be followed by light raking to maximize seed to soil contact.
J.13 Plan Depicting Where and When Species Will Be Planted
Section J.9 contains a description of planting locations.
J.14 Invasive/Exotic Species Control Plan
The nonnative, invasive aquatic predators Louisiana red swamp crayfish and American bullfrog have been observed at the pond mitigation site. These species are known to negatively impact both the California red- legged frog and California tiger salamander. The long term management plan for the project describes management actions that will be implemented to control these species (see Attachment 8).
The project will remove an existing population of the nonnative, invasive Himalayan blackberry that is present on the berm at the pond mitigation site (Figure 5). The removal of this invasive plant species, combined with the planting of wetland vegetation, will increase the overall habitat quality at the project site. Aboveground biomass of Himalayan blackberry will be cut and root material will be removed, to the extent feasible, to reduce the potential for resprouting. Soil disturbance to the pond berm will minimized during removal. The Himalayan blackberry patch occurs on the berm both in the area where mechanized equipment will excavate the berm to replace the culvert outlet and in portions of the berm outside of the culvert replacement work. Therefore, Himalayan blackberry will be removed via both mechanical removal within the footprint of culvert replacement and manual removal in the adjacent areas outside of the culvert replacement footprint. Mechanical removal will be performed with an excavator sitting on the pond bottom.
The area where Himalayan blackberry is present will be converted to a mixture of California annual grassland habitat on the higher elevations portion of the berm and the lower elevation portion of the berm will be planted with wetland vegetation. Following initial removal, invasive plant species will be controlled as described in the maintenance plan in Section M and the long term management plan in Attachment 8.
Calero County Park Pond and Wetland H. T. Harvey & Associates 56 Restoration Project MMP April 26, 2016 Figure 13. Himalayan Blackberry Scrub on the Berm at the Pond Mitigation Site (October 2015).
J.15 Proposed Grading Plan
The proposed grading plan is presented in Section J.2.
J.16 Soil Management
A portion of the pond mitigation site will be excavated and cut materials will be placed in an on-site spoils pile. The spoils pile will be graded to create gentle, non-erosive slopes that fit in with the surrounding topography and will be lightly compacted, and seeded with the native erosion control seed mix. Imported bentonite will be used to line the pond to reduce percolation losses. Some of the excavated pond material will be placed over the bentonite as a protective layer and as the biologically active surface soil layer on the pond bottom (see Section J.2. for details).
Seasonal wetland will be established at the pond and wetland mitigation sites by excavation and cut materials will be placed in a spoils pile southeast of the pond mitigation site. Imported bentonite will be used to line the seasonal wetland establishment areas. Some of the excavated material from the pond restoration area will be placed over the bentonite as a protective layer and as a growing medium for wetland vegetation.
Restoration of the upper seasonal wetland will involve removal of soft sediment that will be hauled to the spoils pile southeast of the pond mitigation area (see Section J.2. for details).
Calero County Park Pond and Wetland H. T. Harvey & Associates 57 Restoration Project MMP April 26, 2016 J.17 Erosion Control Measures
Erosion control measures to be implemented during construction are minimal, as this project will be constructed in the dry season (see Attachment 7 for specific measures required by the Habitat Plan). Seep water will be diverted away from the pond prior to construction to dry out the pond and reduce or eliminate the need for pond dewatering and the associated potential for conveying sediment-laden water from the pond. Frequent travel to and from the site is not anticipated. A stabilized construction entrance may be temporarily installed during project construction at the entrance off of McKean Road and street sweeping will be performed as needed at the paved roadway access point to the project. Post-project erosion control measures will be implemented to help stabilize excavated areas including seeding, spreading weed-free straw, laying erosion control blanket, plant installation, and cattle exclusion. Erosion control blanket will be applied, where necessary, on constructed slopes that will be above water. Areas to be protected by erosion control blanket may include pond and wetland slopes, top of berm in the pond restoration area, the spoils pile and excavated hillside ditches. Temporary construction fencing will be placed to exclude animals and humans from the project area. Permanent cattle exclusion fencing will be included around the pond and wetland areas to protect against overgrazing which can cause trampling of vegetation, soil compaction, development of “cow contours,” and bank destabilization. The spoils pile will be seeded and mulched to create vegetative cover to stabilize the soil and fiber wattles may be placed on the slopes, if necessary to minimize sediment in runoff.
J.18 Itemized Budget
Table 8. Itemized Budget Estimate
Budget Item Minimum Cost Estimate Land acquisition
Planning and engineering design Legal fees Mobilization Construction Short-term, post construction maintenance Monitoring (5 years) Total
Calero County Park Pond and Wetland H. T. Harvey & Associates 58 Restoration Project MMP April 26, 2016 J.19 For stream or Pond Restoration Projects Include Section-J Items 1-14 and the Following:
i. Rosgen classification including: bankfull depth mean and max; floodprone width; width/depth ratio; channel slope; sinuosity – Not applicable because the project is not restoring a stream channel.
ii. Planform geometry – Not applicable because the project is not restoring a stream channel.
iii. Channel cross-sections – Not applicable because the project is not restoring a stream channel.
iv. Longitudinal profile – Not applicable because the project is not restoring a stream channel.
v. Sediment grain sizes – See Section H.3.1.
vi. Watershed size – See Section F.4.
vii. Design discharge – Not applicable because the project is not restoring a stream channel and the overflow capacity at the pond and wetland mitigation sites is not being changed from existing conditions.
viii. Description of avoidance and minimization measures
The project has been designed to avoid and minimize adverse effects to waters of the U.S and State and to species covered under the Habitat Plan. Attachment 7 contains aquatic avoidance and minimization measures that will be conducted during project construction. These measures are derived from the conditions of the Habitat Plan and include the relevant aquatic avoidance and minimization measures described in Table 5- 2 of the Habitat Plan.
ix. Description of bioengineering (design should include native materials); description of: bank stabilization on targeted stream reaches, placement of large woody debris, gravel placement and cleaning
Soil on the cut slopes in the pond and wetland mitigation areas will be stabilized via broadcast seeding with a seed mix of native herbaceous species and the application of weed free straw. Bank slopes will not be subject to fluvial stress in these ponded areas.
Calero County Park Pond and Wetland H. T. Harvey & Associates 59 Restoration Project MMP April 26, 2016 Salvaged soil from pond excavation will be placed as a soil cover/growing medium (0.5- 1 feet thick) above typical water surface elevation (WSE) to encourage plant growth and stabilization of bank soils by plant roots. Taller cut slopes that are above typical WSE will be laid back to a slope no steeper than 2 feet horizontal to 1 foot vertical to reduce erosive potential and covered with salvaged soil from pond excavation (0.5-1 feet thick). They will also be stabilized via broadcast seeding with a seed mix of native herbaceous species. Excavated hillside seep collection and drainage ditches to the pond springbox will be stabilized via broadcast seeding with a seed mix of native herbaceous species. In a natural channel flowing to the springbox, grade control consisting of log jams and rock riffles derived from local materials will be manually installed to reduce flow velocity and trap sediment.
x. Description of riparian plantings (as appropriate) and removal of invasive, nonnative plants
Section J.7-11 contains details of the project’s planting plan and invasive plant species control plan.
xi. Description of any existing riffle-pool complexes, and/or special aquatic sites
Not applicable. The project site does not include riffle-pool complexes or special aquatic sites.
xii. Discussion of existing aquatic fauna and their times of breeding/spawning
Both the California red-legged frog and California tiger salamander breed during the winter breeding season which overlaps with the rainy season and typically starts in the middle of October and lasts until March. California tiger salamander larvae will typically metamorphose, and juveniles will leave a breeding pond, between mid-May and late summer. California red-legged frog larvae will typically leave the pond from July to August. There are no current documented observations of the California red-legged frog and California tiger salamander in the pond mitigation site. Western pond turtle will typically inhabit a pond only when it has sufficient water for them to forage. In order to avoid impacts to the California red-legged frog, California tiger salamander, and western pond turtle, project construction will occur when individuals and larvae are expected to have left the pond and when the pond is dry.
xiii. Location of grazing rotation and targeted fencing to maintain appropriate vegetation and to reduce existing or potential erosion issue
Calero County Park Pond and Wetland H. T. Harvey & Associates 60 Restoration Project MMP April 26, 2016 Cattle exclusion fencing is shown for the pond mitigation site on Figure 8 and for the wetland mitigation site on Figure 11. Management including grazing is described in Attachment 8.
xiv. Description of avoidance measures (e.g., fencing, flagging, contractor training, etc.)
Project construction will occur outside of the rainy season when the pond is dry. Surveys will be conducted prior to construction for special status plants and any known populations near the project will be flagged and protected with ESA fencing during construction.
J.20 For Preservation Proposals Include Section-J Items 1 From Above and the Following:
Section J.17 is not applicable because this project is not a preservation proposal. However, the pond and wetland mitigation sites are being preserved as part of the Habitat Plan and the buffer area and adjacent uplands will be managed as part of the Habitat Plan Reserve system, which provides protections in addition to those provided by Calero County Park.
Calero County Park Pond and Wetland H. T. Harvey & Associates 61 Restoration Project MMP April 26, 2016 Section K. Determination of Credits
The purpose of this section is to describe how many and what types credits will be available as a result of this restoration and creation project. As described elsewhere in this MMP, the Habitat Agency expects to realize a substantial increase in the ecosystem functions and values associated with this project. It should be noted, that while not included in the overall credits established, this project will also result in even greater ecosystem values by protecting nearby watershed lands. In addition, the Habitat Agency will also preserve coastal and valley freshwater marsh, seasonal wetland, and pond located outside, but adjacent to, this project area as part of its Reserve System. Based on this, the number of credits to be established for this site are provided below in Table 9.
Table 9. Number and Resource Types of Credits Established
Acres Acres Crediting Compensatory Mitigation Land Cover Type Restored Restored Created Factor Credits Established Coastal and valley freshwater 0.103 75% 0.077 marsh (rehabilitation) Seasonal wetland 0.165 75% 0.124 (rehabilitation) Seasonal wetland (creation) 0.013 100% 0.013 Pond (rehabilitation) 0.219 75% 0.164
As illustrated in Table 9, a 100% crediting factor is proposed where wetlands are created. Creation (establishment) is proposed to receive full (100%) credit, as the created areas have been optimally sited to provide a full suite of wetland functions, will provide a net increase of aquatic resource acreage, and, to eliminate temporal loss and uncertainty, will be implemented prior to impacts from projects proposing to use these credits as compensatory mitigation. A 75% crediting factor is proposed for the rehabilitation aspects of the project. Rehabilitation is proposed to receive reduced (75%) credit, as rehabilitation will not result in a net increase of aquatic resource acreage but will otherwise provide the full suite of wetland functions—many of which are currently lacking at the site—and will also be implemented prior to project impacts.
Calero County Park Pond and Wetland H. T. Harvey & Associates 62 Restoration Project MMP April 26, 2016 Section L. Site Protection Instrument
The Conservation Easement site protection instrument for the project site is still in process and will be provided to the agencies upon finalization. The landowner is the County, the Easement Holder will be the Habitat Agency, and USACE, USFWS, and CDFW will be third party beneficiaries. The Habitat Agency anticipates the Conservation Easement to be finalized by September 2016, at which point the property will be officially enrolled into the Habitat Plan Reserve System. The Conservation Easement will be based on the template attached to RGP 18 (Attachment 3, Appendix C, 2016), which was based on the template attached to the Habitat Plan (Appendix H, 2012).
Calero County Park Pond and Wetland H. T. Harvey & Associates 63 Restoration Project MMP April 26, 2016 Section M. Maintenance Plan
M.1 Description of the Compensatory Mitigation Site’s Maintenance Activities within the Reserve System Necessary to Meet the Program’s Biological Goals and Objectives.
Maintenance and management activities will be conducted during the five year monitoring period following construction until the achievement of the project’s ecological performance standards. Once the standards are achieved, the project will be maintained and managed in accordance with the long term management plan described in Attachment 8.
M.1.1 Vegetation Maintenance
Nonnative, invasive plant species will be controlled to ensure the establishment of target wetland vegetation and increase the overall habitat quality at the project site. Invasive plant species will be targeted for control and control based on a California Invasive Plant Council (Cal-IPC) Inventory rating of moderate or high. Invasive plant species which may be controlled at the project site include Himalayan blackberry, yellow star thistle (Centaurea solstitialis), and black mustard (Brassica nigra) at the pond mitigation site. Invasive plant species control will consist primarily of targeted flash grazing, string trimming, and/or physical removal. Herbicides will not be used to control vegetation at the project site. Invasive plant species control will be conducted in a manner so as to not disturb nesting birds. If invasive plant species control is planned during nesting bird season (February 1 – August 31), a nesting bird survey will be conducted prior to the control activity. The cover of invasive plant species will be assessed during annual monitoring of the ecological performance standards and periodic maintenance visits.
The project contains areas designed to be minimally vegetated to provide open water pond habitat and bare ground for the California tiger salamander. Vegetation cover in these areas will be inhibited by a combination of design features that extend the depth and duration of inundation to limit vegetation establishment and a fencing alignment that allows for cattle grazing access. Additional management actions may be necessary to control vegetation cover in these areas, which may include flash grazing, string trimming, and/or physical removal. Vegetation control in wetland habitats will occur when the pond is dry. If vegetation control is planned during nesting bird season (February 1 – August 31), a nesting bird survey will be conducted prior to the control activity. The cover of vegetation in the open water pond habitat will be assessed during annual monitoring of the ecological performance standards and periodic maintenance visits.
Native wetland vegetation is expected to establish rapidly at the pond and wetland mitigation sites following installation of cattle exclusion fencing and wetland plants. Irrigation will not be provided to the plantings because the pond and wetland are designed with suitable hydroperiod and soils to support the target vegetation. In addition, we do not anticipate a need for replanting.
Calero County Park Pond and Wetland H. T. Harvey & Associates 64 Restoration Project MMP April 26, 2016 M.1.2 Aquatic Predator Control
The nonnative, invasive aquatic predators Louisiana red swamp crayfish and American bullfrog have been observed at the pond mitigation site. These species are known to negatively impact both the California red- legged frog and California tiger salamander. Project construction includes design elements that will allow managers to dry out the pond to control aquatic predators. The abundance of aquatic predators will be assessed during annual monitoring of the ecological performance standards and periodic maintenance visits. The results of monitoring will inform the timing of pond drainage to control predators. The long term management plan for the project, described in Attachment 8, describes, in detail, the management actions that will be implemented to control these species.
M.1.3 Infrastructure Maintenance
Water control/conveyance infrastructure will be upgraded, replaced, and installed during project construction. These infrastructure elements will require regular inspections and maintenance to ensure that they function as designed. Inspections of infrastructure will be conducted during annual monitoring of the ecological performance standards and periodic maintenance visits. The outlet structure from the pond consists of an overflow structure with a gate at the invert that can be operated to drain the pond for predator control. When the pond is drained, the outlet structure will be inspected and manually cleared of any debris and sediment. The outlet structure at the wetland mitigation site will include an overflow weir to regulate water level in the pond. The outlet structure will be inspected annually and manually cleared of debris.
At the pond mitigation site, seep flow is collected in drainage ditches that lead to a springbox and through a pipe that leads to the seep area above the pond or can be diverted to a water tank for cattle use. The drainage ditches will be inspected annually and manually cleaned of debris and sediment dams. The springbox will be inspected annually and manually cleared of debris and sediment. The inlet of the pipe that conveys flow from the springbox to the seep area above the pond will have a grate to limit debris from entering the pipe. The grate and pipe will be inspected annually and cleaned or flushed with pressurized water to remove flow impediments.
All pipes, troughs, and tanks that provide water to cattle will be inspected annually, manually cleared of debris, and any leaks repaired. Fencing and gates will be inspected annually and repaired as necessary to exclude cattle.
Calero County Park Pond and Wetland H. T. Harvey & Associates 65 Restoration Project MMP April 26, 2016 M.2 Maintenance Schedule Attached
Table 10. Maintenance Schedule Years 1-5
Maintenance Year 1 Year 2 Year 3 Year 4 Year 5 Task Vegetation Maintenance Invasive Plant X X X X X Species Control Open Water If necessary If necessary If necessary If necessary If necessary Pond Habitat based upon based upon based upon based upon based upon Vegetation monitoring monitoring monitoring monitoring monitoring Control results results results results results Aquatic If necessary If necessary If necessary If necessary If necessary Predator based upon based upon based upon based upon based upon Control monitoring monitoring monitoring monitoring monitoring results results results results results Infrastructure Maintenance Pond Outlet X X X X X Structure and Drain Maintenance Pond Seep X X X X X Inflow and Springbox Maintenance Cattle X X X X X Infrastructure Maintenance Wetland Outlet X X X X X Structure Maintenance
Calero County Park Pond and Wetland H. T. Harvey & Associates 66 Restoration Project MMP April 26, 2016 M.3 Maintenance Costs Table
Table 11. Annual Maintenance Costs Table
Maintenance Task Frequency per Year Annual Cost Estimate Preparing Maintenance Schedule 1 Preparing Maintenance Logbook 4 Administrative Support 1 Conducting Maintenance 4 Inspections Conducting Invasive Plant 4 Control Aquatic Predator Control 1, if necessary Maintaining Fences and Gates 1 Maintenance of Outfall Drainage 3 Structures Maintenance of Seep Inflow and 3 Springbox Maintenance of Cattle Water 1 Infrastructure Total
Calero County Park Pond and Wetland H. T. Harvey & Associates 67 Restoration Project MMP April 26, 2016 Section N. Ecological Performance Standards
A combination of site-specific physical and target species-specific ecological performance standards will be used to assess achievement of project objectives. The selected performance standards were customized to the project objectives. The proposed standards incorporate the USACE South Pacific Division (SPD) SPD uniform performance standards to the extent practicable. However, to adequately evaluate project performance, some SPD uniform performance standards were modified, others omitted, and additional target species-specific standards were added. The rationale for these modifications and omissions is provided at the end of this Section.
The below performance standards will be used to determine if the pond and wetland mitigation sites are on a trajectory towards establishing self-sustainable and functional habitat in the long term. It should be noted that the proposed monitoring duration (five years) is much shorter than the actual time it takes for an ecosystem to become mature and self-sustainable. Therefore, the performance standards described below are proxies for evaluating whether the mitigation sites are on a trajectory towards the habitat objectives.
Successful achievement of the performance standards will be based on annual monitoring by a qualified biologist and hydrologist for a minimum five year monitoring period. The ecological performance standards include both final quantifiable standards, and interim targets that assess the temporal trajectory of the project and inform management activities. However, failure to meet interim targets does not necessarily indicate that the performance standards will not be met and will not necessarily result in an extended monitoring period. Achievement of the ecological performance standards is required to obtain sign-off from the permitting agencies. Failure to meet the ecological performance standards will require the Habitat Agency to consult with the permitting agencies to identify appropriate remedial measures and/or adaptive management actions. Once the ecological performance standards are met, the below monitoring will cease and the Habitat Agency will manage the project sites in perpetuity in accordance with the long term management (Attachment 8).
1. Target Hydrologic Regime. The pond mitigation site will achieve a target hydrologic regime that supports the California red-legged frog and California tiger salamander breeding by having a portion of the pond inundated by at least two feet of water through August 31 of each monitoring year that exhibits average or above average precipitation.
No quantifiable performance standards will be applied to the wetland mitigation site. However, the hydrologic regime at this site will be monitored to inform assessments of the potential causes of failure, if any, to meet wetland-specific performance standards below.
2. Sedimentation and Geomorphic Stability. The pond and wetland mitigation sites will demonstrate minimal sedimentation as determined by topographic cross-section surveys and review of the hydrologic regime and California red-legged frog and California tiger salamander survey results. Minimal sedimentation is defined as a surface area/volume of sedimentation
Calero County Park Pond and Wetland H. T. Harvey & Associates 68 Restoration Project MMP April 26, 2016 that does not compromise attainment of the other ecological performance standards (e.g., target hydrologic regime, wetland vegetation cover criteria, surface area of restored, jurisdictional pond and wetland habitat).
The pond and wetland mitigation sites will remain geomorphically stable, including the pond berm and outlet works, as assessed by a qualified hydrologist. The pond and wetland will be considered geomorphically stable, as long as the soil movement does not compromise attainment of the other ecological performance standards.
3. California Red-legged Frog/California Tiger Salamander/Western Pond Turtle. The California red-legged frog and tiger salamander will exhibit successful breeding at the pond mitigation site. The western pond turtle will continue to occur at the pond mitigation site.
4. Aquatic Predator Presence/Absence. The abundance of bullfrogs and crayfish in the pond will be managed at levels below current conditions. If annual monitoring determines that the numbers of bullfrogs or crayfish in the pond have increased since the previous year, the pond and associated fringing wetlands will be drained in mid-September of the current year and allowed to dry completely until winter rains refill the pond (i.e., in most years, in December or January).
Because bullfrogs and crayfish are not expected to breed at the wetland mitigation site, no management actions related to these species will occur at this site.
5. Mt. Hamilton Thistle Abundance. The project will maintain a stable or increasing population of Mt. Hamilton thistle at the pond mitigation site. The Mt. Hamilton thistle is currently absent from the wetland mitigation site, therefore, this criterion does not apply to the wetland site.
6. Wetland Vegetation Percent Cover. Average percent cover of wetland vegetation will exhibit an increasing temporal trend across monitoring years at the pond and wetland mitigation sites; evaluated separately. Average percent wetland vegetation cover will be at least 70% in the coastal and valley freshwater marsh and seasonal wetland planting zones (combined) at the end of the 5 year monitoring period at both the pond and wetland mitigation sites.
At the pond mitigation site, vegetation cover will not exceed 50% in the open water pond habitat during any monitoring year to ensure establishment of breeding habitat for the California red-legged frog and California tiger salamander.
Calero County Park Pond and Wetland H. T. Harvey & Associates 69 Restoration Project MMP April 26, 2016 7. Invasive Plant Cover. The average percent cover of nonnative, invasive plant species at the pond and wetland mitigation sites will be less than 5% in each monitoring year. All species with a Cal-IPC rating of moderate or high will be considered nonnative, invasive plant species.
8. Pond and Wetland Restoration/Establishment Surface Area. The project (pond and wetland mitigation sites combined) will restore at least 0.36 acres of USACE/RWQCB jurisdictional pond, seasonal wetland, and freshwater marsh habitat (all habitat types combined).
The project will establish (create) at least 0.03 acres of wetland habitat by converting uplands to wetlands.
Water for Cattle. Sufficient water from the pond springbox and wetland will continue to be provided to cattle, to support the same grazing intensity of the Reserve lands as the existing conditions, while achieving the above ecological performance standards.
A monitoring schedule is provided below:
Table 12. Ecological Performance Standards Monitoring Schedule
Performance Standard Year 1 Year 2 Year 3 Year 4 Year 5 (final) Target Hydrologic Regime X X X X X Sedimentation and Geomorphic X X X (includes cross- X X (includes Stability section surveys) cross-section surveys) California red-legged X X X X X frog/California tiger salamander surveys Predator surveys X X X X X Mt. Hamilton Thistle Abundance X X X X X Temporal Trend Wetland Vegetation Percent X X X X X Cover Invasive Plant Cover X X X X X Wetland Delineation X Photo Documentation X X X X X
N.1.1 Rationale for Modifications to the SPD Uniform Performance Standards
a. Requirements for ≥80% survival of planted stock. This requirement will not be used because percent survival is an indirect method of assessing vegetation establishment and does not directly measure habitat function. In addition, the existing and planted wetland vegetation will spread
Calero County Park Pond and Wetland H. T. Harvey & Associates 70 Restoration Project MMP April 26, 2016 rapidly via vegetative, rhizomatous growth and within one to two growing seasons it will not be possible to distinguish planted individuals from natural recruits; therefore percent survival will not be measurable.
b. Requirements for ≥75% of reference site plant density or percent cover by hydrophytic plants. A discrete percent cover performance standard will be used that takes into account habitat function for target species and is provided below. However, the project site will not be compared to a reference aquatic resource because there are no sites of similar type and landscape position in the vicinity that are under a similar management regime.
c. Requirement of ≥75% of reference site target percent cover, density, or height of native species. A discrete percent cover performance standard will be used that takes into account habitat function for target species and is provided below. However, the project site will not be compared to a reference aquatic resource because there are no sites of similar type and landscape position in the vicinity that are under a similar management regime.
d. Requirement of ≥75% of reference site target species richness amount. A discrete percent cover performance standard will be used that takes into account habitat function for target species and is provided below. Via this metric, plant species richness will be monitored. However, the project site will not be compared to a reference aquatic resource because there are no sites of similar type and landscape position in the vicinity that are under a similar management regime.
e. Use of indices to compress large amounts of information. Ecological indices will not be used because the below performance standards for discrete metrics provide an effective measure of success.
f. Use of Corps-approved reference wetlands or other aquatic resources sites as a benchmark. The project site will not be compared to a reference aquatic resource because there are no sites of similar type and landscape position in the vicinity that are under a similar management regime.
g. Requirements limiting occurrence of exotic and nuisance plant species to ≤100% of reference site, with zero tolerance for species considered highly invasive per the Cal-IPC List. A percent cover performance standard for invasive plants is provided below. However, the project site will not be compared to a reference aquatic resource because there are no sites of similar type and landscape position in the vicinity that are under a similar management regime.
Calero County Park Pond and Wetland H. T. Harvey & Associates 71 Restoration Project MMP April 26, 2016 Section O. Monitoring Requirements
O.1 Monitoring Methods
This section sets forth the monitoring methods to assess each ecological performance standard. Monitoring will be performed by a qualified ecologist and hydrologist. Monitoring data will be compared to the ecological performance standards to determine if the project objectives are being achieved. Monitoring will also inform management activities to direct maintenance and potential remedial measures to ensure the success of the project.
1. Target Hydrologic Regime. Monitoring at the pond mitigation site will include continuous measurements of water levels at the outlet structure, direct rainfall, and outflow from the springbox (per the methods described in Attachment 1) in Years 1 through 5. The data will be downloaded bi-monthly. A qualified hydrologist will analyze the data at the end of each Water Year and compare the observed hydrologic regime to the hydrologic regime success criteria and to the water budget assumptions described in Attachment 1.
Monitoring at the wetland mitigation site will include continuous measure of water levels at the outlet structure and manual measurements of flow from the outlet structure to the water trough during bi-monthly visits to download the data in Years 1 through 5.
2. Sedimentation and Geomorphic Stability. Sedimentation monitoring of the pond and wetland mitigation sites will be conducted during repeat cross-sections surveys in Years 3 and 5 to assess the degree of sedimentation at each site following construction. Two cross sections at each site will be surveyed in the fall during wadeable conditions and reviewed by a qualified hydrologist. The endpoints of the cross-section locations will be permanently marked (e.g., with T-posts) during preparation of the As-built report/surveys and re-surveyed in Years 3 and 5.
A qualified hydrologist will also conduct a single annual visual assessment of geomorphic stability at both sites during the dry season; this assessment will include inspection of the pond and wetland water-related infrastructure.
3. California Red-Legged Frog/California Tiger Salamander/Western Pond Turtle.
California red-legged frog. A qualified biologist, approved by the Habitat Agency according to the terms of the Habitat Plan, will conduct visual encounter surveys for California red- legged frogs in the pond and wetland in March–April once a year during the 5 year monitoring period. The general survey methods will follow those in the most recent Wildlife Agency
Calero County Park Pond and Wetland H. T. Harvey & Associates 72 Restoration Project MMP April 26, 2016 protocol (currently USFWS [2005]), except that only a single nighttime survey will be performed in March–April, and if no California red-legged frogs are detected during that survey, a second nighttime survey will be performed in May. If red-legged frogs are detected during these nighttime surveys, during California tiger salamander larval surveys, or incidentally, the biologist will record the number of adults, larvae, and egg masses observed, as well as the amount of time spent conducting nighttime surveys (to enable relative abundance estimates, i.e., number of animals per sample or per unit time). The biologist will qualitatively assess the general condition of vegetation (or other features being used for egg attachment), depth, turbidity, and pond temperature. The presence and numbers of nonnative predators observed will be recorded. If the pond is unoccupied, the biologist will identify potential factors hindering successful breeding.
California tiger salamander. A qualified biologist, approved by the Habitat Agency according to the terms of the Habitat Plan, will conduct dipnet larval surveys for California tiger salamanders in the pond in April-May once a year during the 5-year monitoring period. Survey methods will follow those described in the most recent Wildlife Agency protocol (currently USFWS and California Department of Fish and Game [2003]), except that the first survey will be performed in April, and if no California tiger salamanders are detected during that survey, a second survey will be performed in May. If tiger salamanders are detected, the biologist will record the number of adults, larvae, and egg masses observed, as well as the total number of dipnet samples (to enable relative abundance estimates, i.e., number of animals per sample). The biologist will qualitatively assess the general condition of vegetation (or other features being used for egg attachment), depth, turbidity, and pond temperature. The presence and numbers of nonnative predators and suspected nonnative hybrid (California x barred) tiger salamanders observed will be recorded. If the pond is unoccupied, the biologist will identify potential factors hindering successful breeding.
Western pond turtle. A qualified biologist will conduct visual encounter surveys for western pond turtles in the pond in March–April once a year during the 5 year monitoring period. Surveys will occur on sunny days (not overcast or during rain events) during daylight hours, when sustained winds are less than 10 miles per hour and temperatures are between 60°F and 95°F. These conditions are most conducive for basking by western pond turtles. If no western pond turtles are detected during the initial survey, a second survey will be performed in May. If western pond turtles are detected, the biologist will record the number of adults and juveniles observed, as well as the sex of each individual. The biologist will also qualitatively assess the general condition of the pond for western pond turtles (i.e., extent of open water and availability of basking habitat). If the pond is unoccupied, the biologist will identify potential factors contributing to the absence of pond turtles.
Calero County Park Pond and Wetland H. T. Harvey & Associates 73 Restoration Project MMP April 26, 2016 4. Aquatic Predator Presence/Absence. The abundance of aquatic predators (i.e., bullfrogs and crayfish) will be estimated during the above surveys for California red-legged frog, California tiger salamander, and western pond turtle.
5. Mt. Hamilton Thistle Abundance Temporal Trend. The ecologist will conduct a single survey during each monitoring year to characterize the extent and distribution of Mt. Hamilton thistle using the California Native Plant Society Vegetation Rapid Assessment Protocol (California Native Plant Society 2004). The survey area will include both the pond and wetland mitigation sites. All individual Mt. Hamilton thistle plants encountered will be mapped. The survey will document the number of individuals, percent cover, the condition of the occurrence, threats and adjacent land uses, and the location (polygon data) of the occurrence using a GPS. One photo of each occurrence will be taken. The location (point data) where the photos are taken will be documented using a GPS unit so that photos can be captured at the same location during subsequent visits.
The temporal trend in Mt. Hamilton thistle abundance will be assessed at the pond mitigation site for the entire 5 year monitoring period to determine if the performance standard is met. This will entail graphing the total number of individuals observed by monitoring year, over the 5 year period. A statistical correlation analysis may be used, if warranted, to assess the temporal trend.
If detected at the wetland, the same type of graph will be generated for the wetland, although the wetland site is not subject to a performance criterion.
6. Wetland Vegetation Percent Cover. Wetland vegetation percent cover monitoring will be conducted at the end of the seasonal wetland vegetation growing season (early summer) by a qualified restoration ecologist. Percent cover of planted and naturally recruited wetland vegetation will be determined using the quadrat sampling method (Bonham 1989) along permanent transects placed within the coastal and valley freshwater marsh and seasonal wetland planting zones (the planting zones within the cattle exclusion fencing) at the pond and wetland mitigation sites. Transect endpoints will be field marked with metal U-posts. The number of quadrats employed will be based on the variability of the site’s vegetative cover, and will be determined by evaluating the average cover value of wetland indicator species obtained over an increasing number of quadrats. The number of quadrats used will be the point where additional samples do not substantially change the average cover value obtained (Kershaw 1973). Initially, a minimum of 20 quadrats (~ 1.5% of the surface area) will be sampled. Cover within each quadrat will be estimated to the nearest whole percent. Wetland vegetation will be defined as species with a facultative, facultative wetland, or obligate wetland indicator rating in the National Wetland Plant List (Lichvar 2012).
Calero County Park Pond and Wetland H. T. Harvey & Associates 74 Restoration Project MMP April 26, 2016 Percent cover in the open water pond habitat at the pond mitigation site will be monitored concurrently with wetland vegetation percent cover monitoring. Cover in the open water pond habitat will be visually estimated (not with quadrat method) because it is anticipated that vegetation cover will be spatially scattered-unlike the seasonal wetland and freshwater marsh areas. If ponding depth is too great to accurately estimate cover in the open water area, the biologist will resurvey the site later in the growing season, when the pond is drawn down. The results will be compared between monitoring years and the final performance standard in successive monitoring reports.
7. Invasive Plant Cover. The ecologist will conduct a single focused visual survey of the project site annually in late June or early July of each monitoring year. The ecologist will prepare a map that depicts the extent and severity (high density: 51–100% of area; medium: 26–50%; low density: 6–25%) of the invasive plants (defined as invasive species with a Cal-IPC “Impact” or “Invasiveness” rating of Moderate or High). All species with a Cal-IPC rating of moderate or high will be considered invasive plant species.
8. Wetland Delineation for Wetland Establishment/Creation and Restoration Areas. A wetland delineation will be conducted at the pond and wetland mitigation sites to determine whether jurisdictional wetlands have been established/created. Assuming that the project site receives average precipitation, the surface area of jurisdictional wetlands will be mapped by conducting a wetland delineation at the end of the five year monitoring period, following the guidelines outlined in the Corps Manual (Environmental Laboratory 1987) and the Arid West Supplement (USACE 2008). If the required wetland mitigation acreage is not achieved in Year 5, the delineation will be repeated in successive years, if necessary, to confirm that the mitigation requirement has been met.
9. Photo Documentation. Photo documentation of the pond and wetland mitigation sites will be conducted during each monitoring year. Additional photographs will be taken to record any event that may significantly affect the success of mitigation, such as flood, fire, or vandalism. Photo documentation points were established during pre-project surveys (See Attachment 3) and additional photo documentation points will be established in the as-built report following project construction.
O.2 Monitoring Period
Successful achievement of the ecological performance standards will be based on annual monitoring for a minimum five year monitoring period. It is expected that the trajectory of the ecological performance standards will be sufficiently visible during the five year monitoring period. When the performance standards are met, the Habitat Agency will request permitting agency sign-off. The monitoring period may be extended if the project fails to meet the ecological performance standards and the Habitat Agency in consultation with the permitting
Calero County Park Pond and Wetland H. T. Harvey & Associates 75 Restoration Project MMP April 26, 2016 resource agencies determines that additional monitoring is necessary. It should be noted that it may take more than five years for the presence of the California red-legged frog or California tiger salamander to be observed at the project site. The five year monitoring of ecological performance standards is intended to assess the development of suitable habitat and achievement of the habitat objectives for these species, but not necessarily to document the presence of these species. Monitoring for the long term management plan will continue beyond the five year monitoring of the ecological performance standards as described in Attachment 8.
O.3 Notification Memorandum
Within 8 weeks after construction of the pond and wetland mitigation sites is complete, a biological as-built memorandum will be provided to the permitting agencies. The memorandum will be prepared by a qualified restoration ecologist. The memorandum will show any significant deviations in the as-built conditions from the plans described in this site-specific MMP. The memorandum will contain: date(s) all compensatory mitigation construction activities were completed; description of any changes to the project site, project features, or monitoring plan not included in the approved site-specific MMP; summary of compliance status with each special condition of the associated resource agency permits; photo documentation of the pre-project and as- built condition; and a copy of marked up as-built drawings for the project. Maps will comply with the SPD Map and Drawings Standards. Future analysis of the project site will be based on this memorandum.
O.4 Annual Monitoring Reports
Annual monitoring reports will be prepared and submitted to the permitting agencies by December 31 of each monitoring year. Reports will also include the following maps: a vicinity map; and pond and wetland mitigation site maps showing aquatic resource types, photo points, annotated locations of sample points and monitoring stations/transects. Maps will comply with the SPD Map and Drawings Standards. Field data sheets will available for review upon request.
Reports will be prepared using the following outline, in the format of the SPD Mitigation and Monitoring Report Form (Version September 26, 2014):
1. Section A. General Project Information
2. Section B. Notice of Commencement/Completion of Compensatory Mitigation Project 3. Section C. Mitigation Monitoring Status (to include the following subsections - Methods, Results and Discussion, and Recommended Management Actions) 4. Section D. Photo Log 5. Section E. Photograph Locations
Calero County Park Pond and Wetland H. T. Harvey & Associates 76 Restoration Project MMP April 26, 2016 Section P. Long Term Management Plan
Attachment 8 presents the project’s long-term management plan.
Calero County Park Pond and Wetland H. T. Harvey & Associates 77 Restoration Project MMP April 26, 2016 Section Q. Adaptive Management Plan
If monitoring or other information indicates that the pond and wetland mitigation sites are not progressing toward meeting the ecological performance standards, the Habitat Agency will notify the permitting agencies and prepare an analysis to identify the cause(s) of failure. The Habitat Agency will consult with the permitting resource agencies to identify appropriate remedial measures and adaptive management acceptable to the agencies.
The Habitat agency is the responsible party that will develop remedial measures in the event that the project’s ecological performance standards and monitoring requirements are not met. These measures may include: site modifications such as excavation, sediment removal, or replanting; design changes; changes to the maintenance plan and maintenance activities; revised ecological performance standards; and a revised monitoring period. The measures will be designed to ensure that the project provides the aquatic resources described in the approved site-specific MMP and achieves the project’s long term objectives. Ecological performance standards may be revised to account for the implemented remedial measures. Ecological performance standards may also be revised to reflect changes in management strategies and objectives if the new standards provide for ecological benefits that are comparable or superior to the approved site-specific MMP. Remedial measures and adaptive management activities will be described in a monitoring report and/or additional documentation will be prepared as necessary.
Calero County Park Pond and Wetland H. T. Harvey & Associates 78 Restoration Project MMP April 26, 2016 Section R. Financial Assurances
The Santa Clara Valley Habitat Plan Regional General Permit (RGP) #18 (SPN-2012-00302S) Attachment 3 Compensatory Mitigation Strategy for Santa Clara Valley Habitat Plan Regional General Permit Prior to Approval of a Proposed In-Lieu Fee Program: Program-level Interim Mitigation Strategy Document (IMS program) describes a process for providing financial assurances for IMS projects, such as this Calero County Park Pond and Wetland Restoration Project (USACE 2016). In summary, the Habitat Agency must ensure that the fees paid for impacts are sufficient to address the short- and long-term mitigation obligations associated with each IMS compensatory mitigation site. The Habitat Agency will demonstrate assured funding by providing the endowment account balance to the Corps annually, with a summary of the proportional obligations of the IMS compensatory mitigation sites.
The IMS program specifically requires that the Habitat Agency Board will provide a “formal, documented commitment” in the form of a letter from the Board to the Corps stating that the Habitat Agency will fund the mitigation costs identified in the site-specific MMPs for any creation/restoration sites proposed for use as permittee-responsible mitigation under the IMS. Attachment 13 includes a draft letter that the Executive Officer will sign once approved by the Habitat Agency Governing Board at its next meeting on June 16, 2016.
Calero County Park Pond and Wetland H. T. Harvey & Associates 79 Restoration Project MMP April 26, 2016
Section S. Other Information
S.1 Other Agency Permits (If Required)
Other permits and/or approvals through the Habitat Plan process will be required from CDFW, RWQCB, and USFWS.
S.2 Real Estate Records (If Applicable) Attached:
Preliminary Title Report, legal description, parcel map; plat map; title insurance
☒ attached (Attachment 9)
S.3 Phase I Environmental Site Assessment Attached
☒ attached (Attachment 10)
S.4 Biological Resources Survey Attached
☐ attached (Attachment 11)
S.5 Cultural, Historical, Archaeological, and Native American Resources Report Attached
☒ attached (Attachment 12)
S.6 GIS Data (Polygons Only):
The permittee will submit the following within 60 days of Corps written approval of mitigation plan:
• GIS data provided on a digital medium (attach CD or DVD)
• File transfer protocol via shapefile format
• Maps of mitigation site in accordance with Corps SPD Map and Drawing Standards; include as-built GIS data (polygons only) if any deviations have occurred
Calero County Park Pond and Wetland H. T. Harvey & Associates 80 Restoration Project MMP April 26, 2016
Section T. References
Bonham, C. D. 1989. Measurements for Terrestrial Vegetation. John Wiley & Sons, New York, NY.
[CDFW] California Department of Fish and Wildlife. 2013. Findings of Fact and Natural Community Conservation Plan Permit for the Santa Clara Valley Habitat Plan. Permit 2835-2012-002-03.
[CNPS] California Native Plant Society. 2016. Inventory of Rare, Threatened, and Endangered Plants of California. Cirsium fontinale var. campylon. Version 8-02.
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y-87- 1. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi.
Hayes, M. P., and M. R. Jennings. 1986. Decline of ranid frog species in western North America: are bullfrogs (Rana catesbeiana) responsible? Journal of Herpetology 20:490–509.
[HTH] H. T. Harvey & Associates. 2012. Santa Clara Valley Water District Western Pond Turtle Site Assessments and Surveys at Selected Santa Clara County Locations. Prepared for the Santa Clara Valley Water District. October.
ICF. 2012. Santa Clara Valley Habitat Plan. Prepared for County of Santa Clara, City of San Jose, City of Morgan Hill, City of Gilroy, Santa Clara Valley Water District, and Santa Clara Valley Transportation Authority.
Jennings, C. W., R. G. Strand, and T. H. Rogers. 1977. Geologic map of California: California Division of Mines and Geology, scale 1:750,000.
Kershaw, K. A. 1973. Quantitative and Dynamic Plant Ecology. 2nd Edition. American Elsevier Publishing Company, Inc., New York.
Lawler, S. P., D. Dritz, T. Strange, and M. Holyoak. 1999. Effects of introduced mosquitofish and bullfrogs on the threatened California red-legged frog. Conservation Biology 13:613–622.
Lichvar, R. W. 2012. The National Wetland Plant List. ERDC/CRREL TR-12-11. Hanover, NH: U.S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory.
[NRCS] Natural Resources Conservation Service. 2015. Supplement to the Soil Survey of the Santa Clara Natural Area, California, Western Part.
Calero County Park Pond and Wetland H. T. Harvey & Associates 81 Restoration Project MMP April 26, 2016
Safford, H. D., J. H. Viers, and S. P. Harrison. 2005. Serpentine endemism in the California flora: a database of serpentine affinity. Madroño 52(4):222–257.
Santa Clara County Parks and Recreation Department . 2013. Calero County Park Trails Master Plan.
Shaffer, H. B., R. N. Fisher, and S. E. Stanley. 1993. Status report: the California tiger salamander (Ambystoma californiense). Final report. Prepared for the California Department of Fish and Game.
[USACE] U.S. Army Corps of Engineers. 2008. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region (Version 2.0). U.S. Army Engineer Research and Development Center.
[USACE] U.S. Army Corps of Engineers. 2015. Final 2015 Regional Compensatory Mitigation and Monitoring Guidelines for South Pacific Division. January 12.
[USACE] U.S. Army Corps of Engineers. 2016. Santa Clara Valley Habitat Plan Regional General Permit. File No. 2012-00302S.
[USFWS] U.S. Fish and Wildlife Service. 2005. Revised guidance on site assessments and field surveys for the California red-legged frog. August 2005.
[USFWS] U.S. Fish and Wildlife Service. 2013. Santa Clara Valley Plan—Native Endangered and Threatened Species Habitat Conservation Plan Permit. Permit TE94345A-0.
[USFWS and California Department of Fish and Game] U.S. Fish and Wildlife Service and California Department of Fish and Game. 2003. Interim guidance on conducting site assessments and field surveys for determining presence or a negative finding of the California tiger salamander.
Calero County Park Pond and Wetland H. T. Harvey & Associates 82 Restoration Project MMP April 26, 2016 Section U. Attachments
Attachment 1. Hydrology data
Attachment 2. Soils analysis
Attachment 3. Wetland Delineation
Attachment 4. Additional maps of agency jurisdiction
Attachment 5. Aerial photo- historical imagery
Attachment 6. Rancher interview
Attachment 7. Avoidance and Minimization Measures
Attachment 8. Long Term Management Plan
Attachment 9. Real estate records
Attachment 10. Phase 1 Hazardous Materials Assessment
Attachment 11. Biological Resource Survey
Attachment 12. Cultural Resources Report
Attachment 13. Draft Financial Assurance Letter
Calero County Park Pond and Wetland H. T. Harvey & Associates 83 Restoration Project MMP April 26, 2016