HomeMy WebLinkAboutCT 99-04; Villages of La Costa Oaks & Ridge; Tentative Map (CT) (16)DEVELOPMENT
1903 Wright Place, Suite 180
VIA OVERNIGHT MAIL Carlsbad, CA 92008
phone: 760 929-2701
December 18,2001 fax: 760 929-2705
Mr. Don Neu
Senior Planner
City of Carlsbad
1635 Faraday Avenue
Carlsbad, CA 92008-7314
Re: Villages of La Costa-MM&RP 4.4-12
Dear Don:
Enclosed please find a copy of the Vernal Pool Enhancement Plan prepared December 11, 2001
by Helix Environmental for the Bent Avenue property in the city of San Marcos. We are in the
process of negotiating a license agreement with the property owner for entry on this property to
preserve, enhance, maintain and monitor these vernal pools according to this Vernal Pool
Enhancement Plan.
Once we complete the license agreement and contract with the biologist for the scope of work
outlined in this plan, we will deliver to you copies of each and expect that the combination of
this information will satisfy the condition of approval. If you think otherwise, please let me know
at your earliest convenience. If you have any questions or need any further information, please
don't hesitate to call me at 760/929-2701 ext. 103 or e-mail at
j j ackson^moiTo wdevelopment. com.
Sincerely,
Jarpes'M. Jackson
Senior Vice President
JMJ:jmj -
cc Fred Arbuckle - Morrow Development (w/o enclosures)
Jack Henthorri - Henthorn Associates (w/o enclosures)
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^Villages of La Costa ,^
VERNAL POOL ENHANCEMENT PLAN
December 11, 2001
Prepared for:
VILLAGES OF LA COSTA
1
1
1
Carlsbad,
2300 Alga Road
California 92009
Prepared by:
HELIX ENVIRONMENTAL PLANNING, INC.
8100 La Mesa Boulevard, Suite 150
La Mesa, California 91941-6476
1
VILLAGES OF LA COSTA
VERNAL POOL ENHANCEMENT PLAN
TABLE OF CONTENTS
Section Title Page
I. INTRODUCTION 1
H. PROJECT DESCRIPTION 1
A. Project Location 1
B. Project Summary 2
C. Responsible Party 2
III. GOALS OF ENHANCEMENT 2
A. Vernal Pool Habitat to be Restored/Enhanced 2
B. Time Lapse 3
IV. FINAL SUCCESS CRITERIA 3
A. Vernal Pool Target Functions and Values 3
1. Species Richness 3
2. Vegetative Cover 4
3. Weed Cover 4
4. Target Species 5
V. IMPLEMENTATION PLAN:.... 5
A. Rationale for Expecting Implementation Success 5
B. Responsible Parties 5
1. Project Proponent 5
2. Revegetation Specialist 5
3. Installation/Maintenance Contractor 6
C. Schedule 6
D. Site Preparation.. 6
E. Planting Plan 7
1. Vernal Pool Enhancement 7
F. Irrigation Plan 7
VI. MAINTENANCE DURING MONITORING PERIOD 8
A. Maintenance Activities 8
B. Responsible Parties 8
C. Schedule 8
VII. MONITORING PLAN 8
A. Monitoring Methods 8
B. Annual Reports 9
C. Remedial Measures 9
D. Schedule 9
TABLE OF CONTENTS (cont.)
Section Title Page
VIII. COMPLETION OF ENHANCEMENT 10
A. Notification of Completion 10
B. City Confirmation 10
IX. CONTINGENCY MEASURES 10
A. Initiating Procedures 10
B. Funding Mechanism 10
C. Responsible Parties 10
X. LITERATURE CITED 11
LIST OF FIGURES
Follows
No. Title Page
1 Regional Location Map 2
2 Project Vicinity Map 2
3 Vernal Pools Impacts at Villages of La Costa 2
4 Bent Avenue Mitigation Site Vegetation and Sensitive Resources 2
LIST OF TABLES
No. Title Page
1 Oaks Village Vernal Pool Characteristics 1
2 Species Richness Success Criteria 4
3 Vegetative Cover Success Criteria 4
4 Weed Cover Success Criteria 4
5 Target Vernal Pool Plant Species 5
6 Vernal Pool Restoration 7
7 Maintenance Schedule 8
8 Maintenance Monitoring Schedule 9
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I. INTRODUCTION
This enhancement plan provides for the mitigation of impacts to vernal pool habitat on the Oaks Village
of the Villages of La Costa project in the City of Carlsbad, San Diego County, California. The mitigation
and monitoring program for vernal pool habitat and watershed areas discussed in this plan will take
place off site on the Bent Avenue property in San Marcos, San Diego County, California. The mitigation
ratios in this report are based on those presented in the Biological Technical Report for the project
(HELIX, 2001) and the approved Final Environmental Impact Report (EIR) prepared by T&B Planning
(2001). The purpose of this restoration plan is to provide a framework for meeting all mitigation
requirements for impacts to vernal pools consistent with the EIR. The City of Carlsbad will be the
responsible agency for this plan. Included in this document is a summary of project background
information, enhancement plan, and the maintenance/monitoring program.
II. PROJECT DESCRIPTION
A. PROJECT LOCATION
The Oaks Village is located in the City of Carlsbad in northwestern San Diego County, California (Figures
1 and 2). The Oaks Village is approximately 712.6 acres and occurs within the watershed for San Marcos
Creek. A single large hill and its adjoining slopes are the most prominent features on the Oaks Village. A
smaller knoll also occurs in the southwestern corner of the site. Vernal pool habitat is characterized by
depressions in the disturbed habitat areas dominated by vernal pool vegetation. These disturbed habitat
areas were former borrow sites, from which at least 4 feet of soil was removed around 1980 (Figure 3).
Currently, the vernal pool locations within the Oaks Village are dominated by highly rocky soils with
little soil development. These depressions originate from manmade modifications to the site and, as a
result, the overall quality of vernal pool habitat on site is low. Plants observed in the pools include long-
stalk water-starwort (Callitriche marginata), stonecrop (Crassula aquatica), spike-rush (Eleocharis sp.), and
grass poly (Lythrum hyssopifolia). Approximately 1,960 square feet (0.045 acre) of vernal pool habitat
occurs on the Oaks Village. The watershed for each of the pools was also measured and is included with
the acreage in Table 1. Note that vernal pools 1 and 2 share a watershed. No fairy shrimp were observed
in the pools during protocol surveys.
Table 1
OAKS VILLAGE VERNAL POOL CHARACTERISTICS
VERNAL POOL
1
2
3
4
TOTAL
SURFACE AREA
760 sq. ft.
270 sq. ft.
590 sq. ft.
340 sq. ft.
1,960 sq ft.
WATERSHED
20,480 sq. ft./0.47 acre
3,070 sq. ft./0.07 acre
2,670 sq. ft./ 0.06 acre
26,220 sq ft./ 0.6 acre
The vernal pool enhancement site is located in the City of San Marcos, California. It is situated just south
of Highway 78, and west of Bent Avenue (Figure 4). The northern boundary of the site runs along Linda
Vista Drive. The site is completely surrounded by development, and consists largely of annual grassland
as mapped by Dudek and Associates (Dudek 1999). A tract to the east and south of the vernal pool site is
in the process of being developed. The site is located on the San Marcos 7.5 minute United States
Geological Survey (USGS) Quadrate in Rancho Los Vallecitos de San Marcos Township 12 South, Range 3
West, San Bernardino Meridian and Baseline. The site is mostly flat, and elevations range from 535 to 545
HELIX
Vernal Pool Enhancement Plan for Villages of La Costa/MDI-06/December 11, 2001 \
feet above mean sea level (MSL). The project site is an isolated in fill parcel that has no connectivity to
other biologically viable open space.
B. PROJECT SUMMARY
This project has as its goal the enhancement of the 15 vernal pools on site to a more viable condition. The
current condition of these vernal pools is poor due to the impacts of development next to the site as well
as human and vehicular intrusions. This plan will consist of the removal of existing debris, intrusive
weeds, and damage due to vehicular intrusions. There also is a need for restoring contours, lowering
pool basins and building berms near developed property. These actions will need to have some form of
protection (i.e. fencing) during the life of the project as well as after to allow the enhancement efforts to
become established.
C. RESPONSIBLE PARTY
Fred Arbuckle
Real Estate Collateral Management
1903 Wright Place, Suite 180
Carlsbad, CA 92008
(760) 929-2701
III. GOALS OF ENHANCEMENT
A. VERNAL POOL HABITAT TO BE RESTORED/ENHANCED
Mitigation for impacts to vernal pool impacts on the Oaks Village will be achieved through preservation
and enhancement of existing vernal pool surface area. The goal of the enhancement plan will be to
enhance existing vernal pool basins through minor recontouring and removal of invasive weedy species
from the site. Because the existing hydrology is functioning well, no modifications of the hydrology
regime is proposed. The project proponent will be required to preserve and enhance approximately 1,960
ft2 of vernal pool surface area. At the end of the five-year monitoring period, a minimum of 1,960 ft2 of
vernal pools will be restored/preserved as part of the proposed project's mitigation requirements. In
addition to vernal pool surface area, land surrounding the restored/preserved vernal pools will be
preserved and enhanced to maintain an adequate watershed area.
This plan proposes meeting the mitigation requirements off site on the Bent Avenue property in San
Marcos. The vernal pool complex consists of 15 vernal pools ranging in size from 267 square feet to 8,155
square feet (Figure 4). Three sensitive species occur in the vernal pool area: (1) state and federally listed
endangered Sand Diego coyote thistle (Eryngium aristulatum ssp. Paris/iff), (2) federally listed threatened
spreading navarettia (Navarettiafossalis), (3) federal species of concern Orcutt's brodiaea (Brodiaea orcuttii).
Spreading navarretia was observed during previous surveys of the site, but not in 2000. Thread-leaved
brodiaea (Brodiaea filifolia) and San Diego thornmint (Acanthomintha ilicifolia), both federal listed as
threatened species, were recorded in the California Natural Diversity Data Base information for the site,
but were not observed during recent surveys.
HELIX
Vernal Pool Enhancement Plan for Villages of La Costa/MDI-06 / December 11, 2001
I
I
ORANGE SAN DIEGO
SANX/W UNITEDSWS. -
YSIDRO TS^ .. — • — • MEX1CO
HELIX
Regional Location Map
VILLAGES OF LA COSTA VERNAL POOL ENHANCEMENT PLAN
Figure 1
The Ridge Property
The Oaks Property
1000 SOOO 3000 4000 5000 6000 7000 FEET
Source: USGS 7.5 mln Quadrangles: Enclnltas and Rancho Santa Fes.'
HELIX
Project Vicinity Map
VILLAGES OF LA COSTA VERNAL POOL ENHANCEMENT PLAN
Figure 2
SURFAC£fMPROVEMEN.TS
CO BE KElUoVEO -;"---
Scale: 1" = 4000'
JEO CDNNKi WATEH'S
'JG'WATKH .
REDUCTl'OMiSTATlON /
VpOS^AyALES'SiQ.'VSi:"^,''
HELIX
Vernal Pools Impacts at Villages of La Costa
VILLAGES OF LA COSTA VERNAL POOL ENHANCEMENT PLAN
Figure 3
LEGEND
Vegetation
SWS Southern willow scrub
FWM Freshwater marsh
MFS Mule fat scrub
SWET Seasonal wetland
DW Disturbed wetland
OC Open channel
AGL Annual grassland
DIS Disturbed
DEV Developed
li-^-fcl Vernal pools
Sensitive Plants
Bo Orcutt's brodiaea (Brodiaea orcuttii)
Ea San Diego button-celery
(Eryngium aristulatum var.parishii)
* Brodiaea within open space
but for which population size is not given
(total approximately 1,913 individuals)
Project Boundary
Bo 30(V
Survey Boundary
Vernal pool area not
formally delineated
N
Note:
125 125 Feet
This map is based on site conditions as observed'at the time of our field
investigations. The information presented herein was developed by visual
inspection and/or aerial photograph interpretation. Note that both site
conditions and applicable regulatory requirements may change.Job No: SCD-01 Date: 12/4/01
HELIX
Bent Avenue Mitigation Site Vegetation and Sensitive Resources
VILLAGES OF LA COSTA VERNAL POOL ENHANCEMENT PLAN
Figure 4
B. TIME LAPSE
The vernal pool mitigation and monitoring program will take place over a five-year period. Previous
studies (Scheidlinger et al. 1985, Zedler and Black 1989, RECON1997) have shown that restored pools can
support vegetation similar to that of natural pools within 3 to 14 years. The success criteria described
below for this project must be met by the end of the five-year period. These criteria represent an
intermediate stage in the long-term recovery of the preserved and restored pools. Total restoration of the
vernal pool habitat may take as long as 20 years. Meeting the success criteria within the five-year
monitoring period will provide appropriate biotic conditions on site for long-term sustainability of vernal
pool habitat.
IV. FINAL SUCCESS CRITERIA
The following sections provide standards to determine the successful completion of the 5-year mitigation
and monitoring program. Attainment of these standards indicates the mitigation area is progressing
toward the habitat functions and values specified for this plan. Methods to be used to measure these
success criteria are described in the following text.
The City may terminate monitoring earlier than five years if success criteria are met and it is
recommended by the restoration specialist in a year-end report. The year-end report will be considered
complete and acceptable if no comment is received from the City within 30 days of receipt. Likewise, if at
the end of five years, any of the restored areas fail to meet the year-five standards, then the monitoring
and maintenance period will be extended one full year, and a specific set of remedial measures (approved
by the City) will be implemented. Only areas failing to meet the success standards will require additional
work, that is, not all of the areas originally restored. This process will continue until all year-five
standards are met, or as otherwise provided in this document.
A. VERNAL POOL TARGET FUNCTIONS AND VALUES
The goal of the vernal pool mitigation is to restore viable vernal pool habitat. As discussed above in
Section HI-A, mitigation for impacts to vernal pools will require a minimum of 1,960 ft2 of vernal pool
preservation and enhancement.
In order to measure the success of the restored vernal pools, the focus will be on the elimination of weedy
species from the site. Species richness and vegetative cover for both native and non-native species in the
enhanced vernal pools will be qualitatively measured through visual assessments. Target functions and
values are described below.
1. Species Richness
Only vernal pool indicator species will be included in the measurement of species richness in any of the
vernal pools. Annual performance goals are provided for years 3 through 5 are expressed as the number
of vernal pool indicator species in Table 2. Acceptable species richness within each of the enhanced pools
at the end of the five-year monitoring period will be a minimum of four vernal pool indicator species per
pool. Meeting the 100 percent criterion by the fifth year will show that the pools are functioning and that
they would be expected to continue functioning. If the species richness goal for a given year is not met,
corrective measures (e.g., reseeding, excavation of a portion of a basin, introducing new inoculum,
berming of a pool edge, etc.) will be taken to ensure eventual achievement of the long-term goals.
HELIX
Vernal Pool Enhancement Plan for Villages of La Costa/MDI-06/December 11, 2001
4. Target Species
Target species are listed in Table 5. The goal of the mitigation plan will be to have a minimum of four
target species in each vernal pool at the end of the five-year monitoring period. Any transfer of seeds to
inoculate pools shall be limited to seeds collected from pools on site.
Table 5
TARGET VERNAL POOL PLANT SPECIES*
Common Name Scientific Name
Vernal Pool Indicators*
American pillwort
Annual hairgrass
Crassula
Flowering quillwort
Long-stalk water-starwort
Popcorn flower
San Diego button-celery
Spreading navarretia
Plantago
Woolly marbles
Pilularia Americana
Deschampsia danthonoides
Crassula aquatica
Lilaea scilloides
Callitriche marginata
Plagiobothrys acanthocarpus
Eryngium aristulatum var. parishii
Navarretia fossalis
Plantago elongata
Psilocarphus brevissimus
Other Wetland Species
Common toad-rush
Pale spike-sedge
Juncus bufonius
Eleocharis macrostachya
' Based on ACOE Vernal Pool Plant Indicator List (ACOE1997).
V. IMPLEMENTATION PLAN
A. RATIONALE FOR EXPECTING IMPLEMENTATION SUCCESS
The areas selected for vernal pool enhancement currently support degraded vernal pools and non-native
habitat. This plan would enhance the vernal pool and watershed area. No new pools will be created.
Additionally, the project team is comprised of a number of individuals who have been involved in the
successful implementation of vernal pool restoration efforts.
B. RESPONSIBLE PARTIES
1. Project Proponent
The project applicant (Real Estate Collateral Management) will be responsible for financing the
installation and monitoring of the mitigation measures (see section II-C above).
2. Revegetation Specialist
Overall supervision of the installation, maintenance and monitoring of this mitigation project will be the
responsibility of a revegetation specialist with vernal pool restoration experience. The revegetation
specialist will educate all participants with regard to mitigation goals and requirements, and directly
oversee the enhancement effort. After each monitoring event, the revegetation specialist will provide the
project proponent and contractor with a brief report, including a written list of items in need of attention.
HELIX
Vernal Pool Enhancement Plan for Villages of La Costa/MDI-Q6 / December 11, 2001
Table 6
VERNAL POOL RESTORATION
Pool
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Area (ft2)
4171.34
989.25
2479.66
267.13
2614.81
1317.75
865.12
1030.22
420.28
1647.91
1098.00
3701.66
470.28
8155.53
481.06
Conditions
Debris
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Ruts
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Weeds
•
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•
•
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•
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•
•
Enhancement
Steps
Rake out tire ruts. Remove debris, and weeds.
Remove debris. Remove weeds. Level tire ruts.
Smooth out tire ruts. Remove weeds. Rake pool.
Remove weeds. Gopher damage. Deepen and
restore contours.
Remove weeds and tire ruts. Lower high spot in
pool.
Level tire ruts. Extract weeds.
Remove weeds. Smooth out tire ruts. Restore
contour. Rake pool.
Restore contour. Extract weeds.
Deepen pool. Restore contour. Remove weeds.
Rake out bottom of pool. Remove weeds.
Level tire ruts. Remove debris and weeds. Remove
high spots and re-contour.
Smooth out high spots. Remove weeds.
Deepen pool four inches. Restore contour. Level
tire ruts.
Berm edge next to fence. Combine with pool#15.
Restore contour.
Remove weeds. Allow drainage to occur south into
drainage ditch.
E. PLANTING PLAN
1. Vernal Pool Enhancement
Partly because vernal pools recur reliably in the same location year after year, many vernal pool species
are adapted for a strategy of non-dispersal (Zedler 1990). Hand tools (i.e., shovels and trowels) will be
used to remove soil from the enhancement pools where necessary. The preserved pools will not receive
inoculum initially. Upland species, including native bunchgrasses and sage scrub species may be
supplemented following the initial weeding effort in the watershed areas.
F. IRRIGATION PLAN
No irrigation is planned or considered necessary for this project.
HELIX
Vernal Pool Enhancement Plan for Villages of La Costa/MDl-06/December 11, 2001
Vernal Pools
Monthly inspections of the restoration and maintenance efforts will be performed during the rainy season
(February through June ) and every other month during the non-rainy season the first three years, and
every three months during the remainder of the monitoring period. Plant and animal species observed in
each pool during the monitoring visits will be recorded.
An annual monitoring visit will be conducted each year near the end of the rainy season when most
vernal pool species are visible. The exact timing of annual monitoring will be dependent upon the time
and amount of rainfall received each year. Monitoring will consist of a visual assessment of the enhanced
vernal pools. All plant species present within each pool will be identified and recorded. Plant cover of
both weedy native species will be estimated within pool. Photo documentation points shall be established
for the preserve area and photographs will be taken of each pool during the annual monitoring event.
Representative photos will be provided in the annual monitoring report.
B. ANNUAL REPORTS
As part of the monitoring program, annual reports prepared by the maintenance contractor will be
submitted to the City evaluating the success of the mitigation effort to date, along with any
recommendations for future work that may be deemed necessary. The annual monitoring report will
include data collected throughout the year in addition to the annual monitoring visit.
C. REMEDIAL MEASURES
If the annual goals are not being met, corrective measures will be implemented. Corrective measures may
include, but are not limited to, importing new inoculum from on site, recontouring of non-functioning
pools and re-seeding with collected or commercially available seed. Pools exhibiting appropriate
hydrological characteristics but low species cover and richness will be re-seeded with vernal pool plant
species. Prior to conducting any significant remedial measures the City will be notified.
D. SCHEDULE
Maintenance and monitoring events are summarized in Table 8. Monitoring events that focus on
botanical data collection (i.e., percent cover, density, phenology, etc.) will occur annually for five years.
The first annual botanical monitoring event will occur in the spring following initial enhancement.
Reports will be prepared and submitted to the City by October of each year to ensure adequate time
remaining in the dry season to make any necessary alterations to the preserve areas.
Table 8
MAINTENANCE MONITORING SCHEDULE
PHASE
Grading/ Site Preparation
Installation
SCHEDULE
2 times per week
Daily
Post Installation
Yearl
Year 2
February to July
August to January
Years 3 to 5
Monthly
Monthly
Twice: September and December
Quarterly: March, June, September,
and December
HELIX
Vernal Pool Enhancement Plan for Villages of La Costa/MDI-06 / December 11, 2001
X. LITERATURE CITED
HELIX Environmental Planning Inc. 2001. La Costa Oaks-Ridge Village Biological Technical Report.
Prepared for Morrow Development.
T & B Planning Consultants, Inc. 2001. Final Program Environmental Impact Report for the Villages of
La Costa. Prepared for the City of Carlsbad.
HELIX
Vernal Pool Enhancement Plan for Villages of La Costa/MDI-06 / December 11, 2001