HomeMy WebLinkAboutAttachment 8W - Conceptual Mitigation Plan
MEMORANDUM
To: Susan Wynn (FWS), Dimitri Pappas (FWS), Karen Drewe (CDFW), Heather Schmalbach
(CDFW)
From: Scott McMillan and Callie Amoaku, Dudek
Subject: Nirvana Conceptual Mitigation Plan
Date: September 16, 2022
cc: Dai Hoang (City), Oscar Romero (City), Andrew Gracey (OnPoint), Todd Dwyer (OnPoint), Mary
Lanier (McKenna Lanier), Diane Jenkins (McKenna Lanier)
Attachment(s): Figures 1-2
Attachment A
The biological resource mitigation for the Nirvana (821 Main Street) project has been discussed over the past year
with the City of Chula Vista (City) staff, the project owner, and with the Regulatory Agencies (Agencies), with several
options, considered. Both maritime succulent scrub (MSS) and San Diego Ambrosia (Ambrosia pumilla) (Ambrosia)
are the biological resources identified for mitigation on this project (see below).
Early mitigation options considered for this project included evaluation of the City’s Central City Preserve for
mitigation opportunities, and a mitigation program was prepared for that area. B ased on feedback from the
Agencies during the June 8, 2022, meeting, this evaluation was redirected to areas within the Otay Valley watershed
area, including areas on the City’s Otay Ranch Preserve. Dudek restoration ecologist, Scott McMillan, conducted
site visits throughout the Otay Valley and adjacent areas of the Otay Ranch Preserve on July 13 and 14, 2002,
concentrating on lands in City ownership.
Three restoration areas were identified, all within the Otay Ranch Preserve, and all within the Otay Valley watershed
(see Attachment 1). Site 1 is located at the mouth of Salt Creek where it joins the Otay Valley and includes seven
areas for MSS restoration along with an area for restoration of the Ambrosia. Site 2 is located approximately 0.5
miles to the west of Site 1, in an unnamed canyon just east of the Salt Creek drainage, with three areas targeted
for MSS restoration. Site 3 is approximately 0.75 miles upstream from Site 1, within the central part of the Salt
Creek drainage.
1 Mitigation Requirements
Table 1 summarizes the impacts to upland vegetation requiring mitigation (maritime succulent scrub) and the
Narrow Endemic Species on site (San Diego ambrosia (Ambrosia pumila)).
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Table 1. Mitigation for Significant Impacts to Sensitive Vegetation Communities and
Narrow Endemic Plants
Vegetation
Community
MSCP Subarea
Plan Mitigation Ratio Impact s
Mitigation
Acreage Required
(Restoration )
Uplands
Maritime succulent
scrub
Tier I 1:1 13.36 acres 13.36 acres
San Diego ambrosia Covered; Narrow
Endemic
2:1 500 individuals in
0.06 acres
1,000 individuals
in 0.12 acres
2 Restoration
All mitigation of the MSS and Ambrosia will be accomplished with a 7-Year Restoration, Maintenance, and
Monitoring Plan that will include the following:
• Salvage of all cactus and other native plant species from the project site prior to project impacts
• Salvage of the entire Ambrosia population from the project site prior to project impacts
• A greenhouse propagation program where salvaged cactus and Ambrosia cuttings are used to propagate
additional plants for out-planting into the restoration sites
• Planting of restoration sites using both salvaged material and plant propagated in the greenhouse
• Seeding of native seed to establish native understory species and MSS associates that are not established
through the planting program.
• A weed control program that includes initial dethatching of the restoration sites, followed up by 7 years of
aggressive non-native plant control utilizing a combination of hand, mechanical, and herbicide control
methods
• Temporary irrigation of both the MSS and Ambrosia plantings
• Access control that will include fencing, signage, and monitoring of illegal access
• Detailed monitoring of the restoration sites to track survivorship of plantings, growth of native vegetation,
cover of non-native plant species, and other issues
• Success criteria for the MSS, the Ambrosia, and the weed control program.
• Reporting to the City and the Agencies on the performance of the restoration sites and remedial measure
implemented if needed.
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• A detailed cost estimate to implement the project, including all project aspects listed above, as well as cost
for annual inflation applied (current market %)
• As a guarantee of the commitment to achieve project completion and success, the project will include a
Secured Agreement with the City of Chula Vista consisting of a letter of credit, or performance bond
associated with the implementation of the 7 -Year Plan, including a 10% cash deposit, not to exceed
$30,000
• An endowment to the City that will in perpetuity fund annual maintenance and monitoring following the
successful implementation of the restoration and approval by the City and agencies (see below)
3 Site Selection
The three sites proposed below were identified based on field assessment of the Otay Ranch Preserve to identify
areas that have the appropriate disturbed vegetations, soils, slope exposures, and access for the installation,
maintenance, and long-term management of the restored habitats. These three sites have been specifically chosen
based on the following:
• All three sites have appropriately disturbed habitat, consisting of either non-native grassland or heavily
disturbed scrub with minimal native vegetation
• The areas targeted for MSS have appropriate soils, with rocky clay loams
• The area targeted for Ambrosia has clay silty loam soils like the project site’s existing population
• The areas targeted for MSS have appropriate exposures, with south or west facing slopes, or areas that are
relatively flat and on fully exposed landscapes
3.1 Site 1
Site 1 is at the mouth of Salt Creek and has a total of seven MSS restoration areas (totaling 6.60 acres) that are
currently dominated by non-native grasses, with little to no cover of native vegetation (see Attachment 1 and Figures
1-4). These areas have been heavily disturbed with agriculture, off-road activity, and subsequent weed invasion.
Adjacent to these non-native grasslands are intact stands of MSS that can be expanded upon in the restoration
areas, providing added area and improved habitat conditions that will be tied to existing MSS resources. These
seven areas have been designed around active roadways, easements (including the City of San Diego’s Otay
Pipeline Segment 2, A6 alignment), as well as specifically designed to complement the proposed Phase 2 Otay
Valley Wetland Mitigation Bank being planned by HomeFed. Coordination was conducted between Dudek and
HomeFed to ensure that the two mitigation proposals do not overlap, but rather complement each other. With
these complimentary efforts, the mouth of Salt Creek will have all available habitat, both wetland and upland,
restored and managed in perpetuity, providing important biological resources for not just the Salt Creek drainage,
but the Otay Valley watershed as well.
In addition, Site 1 has been identified for the mitigation of Ambrosia through a translocation and restoration
program (Attachment 1 and Figure 2). The Ambrosia restoration area (totaling 0.12 acres) has been placed on soils
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(clay loams) and topography (alluvial terrace) that are known to support Ambrosia at the project site and in other
Ambrosia occurrences throughout the species range.
Finally, the areas identified for restoration in Site 1 have been designed to specifically avoid the FUDS (Formerly
Used Defense Sites) zone that has been identified by the Army Corps of Engineers associated with the historical
bombing range on the south side of Otay Valley.
3.2 Site 2
Site 2 is located approximately 0.5 miles to the west of Site 1, in an unnamed canyon just east of the Salt Creek
drainage, with three areas targeted for MSS restoration (totaling 6.75 acres). These three areas are dominated by
non-native grassland with a low density of scattered California buckwheat (Eriogonum fasciculatum) shrubs.
These three restoration areas are located just south of existing sites where the City’s Preserve Manager, RECON
Environmental, has conducted past MSS restoration. These three restoration areas will provide additional patches
of MSS habitat for greater area and quality of habitat overall for the species that depend on the MSS vegetation, in
particular the coastal cactus wren (Campylorhynchus brunneicapillus), through a program of habitat restoration
and long-term management.
3.3 Site 3
Site 3 is approximately 0.75 miles upstream from Site 1, within the central part of the Salt Creek drainage, with one
area targeted for restoration (totaling 0.71 acres). This area is dominated by non -native grassland with a low density
of scattered California buckwheat shrubs.
This restoration area is located adjacent to existing sites where the City’s Preserve Manager, RECON Environmental,
has conducted past MSS restoration. Like Sites 1 and 2, This restoration area will provide an additional patch of
MSS habitat for greater area and quality of habitat overall for the species that depend on the MSS vegetation
through a program of habitat restoration and long-term management.
4 Endowment
Once the 7-Year Restoration Plan has been successfully implemented, and the City and Agencies have approved
the project sign-off, the long-term management will begin. The long-term management of the three restoration sites
will be funded with an endowment that provides annual funds for management and monitoring in perpetuity. These
funds will be specifically designated for the three restoration sites discussed here, as well as areas adjacent to
these sites where buffer management is warranted. This endowment budget will be in addition to the cost of
successfully implementing the 7-year Restoration Plan.
The annual cost per acre for this endowment was developed by the Otay Ranch Preserve Manager (Recon
Environmental) in coordination with the City and was based on the Preserve’s Area Specific Management Directives
(ASMD’s) as well as the Preserve Manager’s extensive experience managing the Preserve over the last decade. The
annual cost determination included the following:
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SUBJECT: NIRVANA MITIGATION PLAN
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• Annual qualitative monitoring of sites, including photo points
• Annual narrow endemic species monitoring
• Annual MSCP wildlife species monitoring
• Maintenance of access control (fencing and signage)
• Weed control and brush management
• Remedial seeding and/or planting if necessary
• Annual Work Plans
• Annual Monitoring Reports to the City and Agencies
• Meetings and coordination
Based on the directives and tasks described above, the Annual Cost for Long-Term Management was calculated to
be $7,556/acre. The summary of the restoration requirements, proposed mitigation, annual cost for long-term
management and the total endowment that will be required is shown in Table 2 below.
Table 2. Mitigation and Endowment Summary
Vegetation Community
Restoration/
Establishment
Overall
Mitigation
Ratio
Annual Long -Term
Management
Funding
Total
Endowment
Required at
3.5% Return
Maritime succulent scrub 13.36 acres (1:1) in
Restoration Areas 1-11
1:1 $7,556/acre
annually
$2,884,233
San Diego ambrosia 1,000 individuals in
0.12 acres (2:1)
2:1 $7,556/acre
annually
$25,906
TOTAL ENDOWMENT $2,910,139
These endowment funds will be held and managed by the San Diego Foundation in a separate account to be utilized
for the long-term management of the three restoration sites and areas adjacent to these sites if needed to provide
buffer management and improvement to the overall Preserve system. Implementation of long-term management
at these sites utilizing this endowment will be conducted by the Otay Ranch Preserve Manager in cooperation with
the City and the Agencies.
5 Summary
The restoration program will provide a total of 13.36 acres of maritime succulent scrub and 0.12 acres of San Diego
Ambrosia restoration within the Otay Ranch Preserve. The restoration effort will include a 7-year monitoring and
management program, as well as an endowment for long-term management and maintenance as part of the overall
Preserve. The mitigation described above is a conclusion of the discussion between the project owner, the City, the
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SUBJECT: NIRVANA MITIGATION PLAN
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Otay Ranch Preserve Manager, and the Agencies. Sites were identified and chosen based on discussions about
suitability of disturbed habitat, appropriateness of restoration for MSS and Ambrosia, and adjacency to higher
quality habitat.
The Otay Ranch Preserve relies on Community Facilities District (CFD) species taxes paid by the resident annually,
and these funds primarily go for maintenance of the Preserve. There are no other continuous funding sources other
than the CFD, and because this funding is limited to maintenance, there is limited ability to fund more expensive
habitat enhancement and restoration activities. With this limited funding from the CFD, the City is finding some
habitat enhancement and restoration work need to be deferred.
The Nirvana project mitigation will provide the City and Otay Ranch Preserve with another resource to not only
maintain the Nirvana mitigation sites in perpetuity, but also fund enhancement and restoration in other areas of
the Preserve system. Because of this win/win opportunity for both the City and the Otay Ranch Preserve, the City
of Chula Vista fully support the Nirvana project habitat restoration for mitigation in the Otay Ranch Preserve.
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SUBJECT: NIRVANA MITIGATION PLAN
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Figure 1 – MSS Mitigation Site 1
Figure 2 – MSS Mitigation Site 2-3 and San Diego Ambrosia Mitigation Site 1
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Figure 3 – MSS Mitigation Site 4
Figure 4 – Distance View of MSS Mitigation Site 8-10
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Figure 5 – Close View of MSS Mitigation 10
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SUBJECT: NIRVANA MITIGATION PLAN
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ATTACHMENT 1
OnPoint Nirvana Restoration Polygons Otay Ranch Preserve
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Restoration Polygons from Otay Ranch Preserve
OnPoint Nirvana
SOURCE: Esri; San Diego County 2019
0 200100Feet
FIGURE 1-1
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MSS SD Ambrosia SD Ambrosia Restoration Number: Acreage 1: 0.115MSS Restoration Number: Acreage1: 2.4562: 2.6943: 0.480 4: 0.4755: 0.1616: 0.0847: 0.228
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Restoration Polygons from Otay Ranch Preserve
OnPoint Nirvana
SOURCE: Esri; San Diego County 2019
0 200100Feet
FIGURE 1-2
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MSS MSS Restoration Number: Acreage8: 2.6649: 2.38210: 1.701
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Restoration Polygons from Otay Ranch Preserve
OnPoint Nirvana
SOURCE: Esri; San Diego County 2019
0 200100Feet
FIGURE 1-3
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MSS MSS Restoration Number: Acreage11: 0.708