HomeMy WebLinkAbout3338; Agua Hedionda & Calavera Creek Dredging; Carlsbad Blvd Bridge & Basin; 2002-06-17FINAL
HABITAT RESTORATION AND MONITORING PLAN
FOR THE CITY OF CARLSBAD BRIDGE &
THOROUGHFARE DISTRICT NO. 4, THE CALAVERA
HILLS PROJECT, AND THE DETENTION BASINS
PROJECT IN
CARLSBAD, CALIFORNIA
Prepared for
PLANNING SYSTEMS
1530 FARADAY AVENUE, SUITE 100
CARLSBAD, CA 92008
Prepared by
GERALD A. SCHEID
SENIOR BIOLOGIST
RECON NUMBER 3226B
JUNE 17, 2002 'A
1927 Fifth Avenue
San Diego, CA 92101 -2358
P 619,308.9333 F 619,308.9334 O This document printed on recycled paper RECON
TABLE OF CONTENTS
Introduction
Habitat Types Proposed to Be Impacted
Responsibilities
Revegetation
Maintenance and Monitoring
References Cited
1
4
6
8
15
20
FIGURES
Regional Location of the Project
Project Vicinity
Location of Restoration/Mitigation sites
2
3
5
TABLES
Wetland Plant Community Mitigation Summary
Standard Success Criteria
Functional Success Criteria
Riparian Scrub Planting Densities
Plant materials and densities for alkali marsh areas
Seeding Location and Application Rates
Five-Year Maintenance and Monitoring Schedule
Anticipated Exotic Species
1
9
10
12
13
14
15
17
ATTACHMENT
1: 404 Permit
2: Wetland Functional Analysis
Introduction
This habitat restoration and monitoiing plan provides an implementation strategy,
maintenance regime, and monitoring goals for the ultimate creation of 10.7 acres of
wetland/ripaiian habitat as mitigation for impacts to 2.87 acres jurisdictional waters
(0.7 acre of Clean Water Act [CWA] jurisdiction, and 2.87 acres are under the State Code
jurisdiction) as part of the Calavera Hills Master Plan Phase n and Bridge and
Thoroughfare District No. 4 projects. A copy of the 404 permit issued for the project is
provided for reference (Attachment 1).
The project site is located in the northeast quadrant of the city of Carlsbad (Figures 1
and 2) and consists of three components: Calavera Hills Master Plan Phase II area. Bridge
and Thoroughfare District No. 4, and two proposed detention basins. The Calavera Hills
Master Plan area is bounded by State Route 78 (SR-78) in the north with the southern
boundary being an east-west line approximately one-half of a mile north of the Rancho
Carlsbad Mobile Home Park. Current land use in the area is predominantly agricultural
with remnant southern mixed/chamise chaparral and Diegan coastal sage scrub.
Agricultural development has reduced and confined the remaining riparian vegetation to a
narrow strip along Calavera Creek.
The project will temporarily impact 0.4 acre and directly impact 2.47 acres of
jurisdictional waters including wetlands. The mitigation ratios required for each
vegetation type are summarized in Table 1. Of the 2.87 acres of impacted jurisdictional
area (0.7 acre CWA; 2.87 acres State Code), 1.71 acres are occupied by the federally
listed least Bell's vireo. All impacts to wetlands are considered significant and will be
mitigated by the creation of 10.7 acres of wetland/riparian habitat on Calavera and Little
Encinas Creeks, although only 9.9 acres of mitigation is required.
OCEANSIDEv SAN MARCOS
PROJECT LOCATION
CARLSBAD
ENCINITAS^
0
t
0 MILES 2.2
M:jobs\3225e\graphics\reginal.cdr
4.4 FIGURE 1
Regional Location of the Project
K
t
Man-made pond
Master Plan Phase II
Bridge and Thoroughfare District
Detention basins
Feet 2000
FIGURE 2
Project Vicinity
TABLE 1
WETLAND PLANT COMMUNITY MITIGATION
Plant Community
Project
Impacts
(acres)
Mitigation
Ratio
Required On-
Site Mitigation
(acres)
Riparian
woodland/scrub'"
1.71 4:1 6.84
Riparian woodland/scrub 0.71 3 1 2.13
Riparian forest 0 3 1 0
Cismontane alkali marsH 0.18 3 1 0.54
Freshwater marsh 0.05 3 1 0.15
Non-wedand
jurisdictional waters
0.24 1 1 0.24
TOTAL 2.87 9.9
* 1.71 acres of riparian woodland/scrub to be impacted are occupied by
the least Bell's vireo.
Mitigation will be carried out on-site by creating restoration areas along Calavera and
Little Encinas Creeks (Figure 3). The northernmost mitigation site on Calavera Creek will
widen the existing Calavera Creek channel to create 7.4 acres of additional wetland. The
mitigation site on Little Encinas Creek will create 3.3 acres of wetlands within the "BJ"
detention basin.
In all restoration areas the existing non-native vegetation will be replaced with either
southern willow scrub, freshwater marsh, cismontane alkali marsh, or a combination of
these habitat types. Where appropriate, the southern willow scrub vegetation will be
augmented with riparian forest (e.g., western sycamore), riparian woodland (various
native willow species), and alkali marsh species (e.g., spiny rush, yerba mansa, saltgrass).
These mitigation sites will add to and enhance the current riparian mosaic that supports
least Bell's vireo along Calavera Creek.
This habitat restoration and monitoring plan provides guidelines, design criteria, and
construction methods through which a functioning wetland and riparian plant community
can be created. Because the construction of the roadway links is expected to be phased,
installation of mitigation may also be phased.
Habitat Types Proposed to Be Impacted
The extension of College Boulevard and Cannon Road and the Phase n Master Plan
would temporarily and permanently impact a total of 2.87 acres of jurisdictional waters
(0.7 acre CWA; 2.87 acres State Code), including riparian scrub, woodland and forest
vegetation, seasonal and perennial cismontane alkali marsh, and non-wetland waters. A
El''* Ave
1.
0
M:\ioh^V,1225h\gi^\hn)let- aprvl ig.>(RL.\t.t>» tinaJ l()/26/(K)
Restoration/mitisation area
O'S^ College Boulevard Alignment 1
Cannon Road Alignment 1
Diegan coastal sage scrub
I Southern mixed and chamise chaparral
I Riparian forest
I Riparian woodland
] Riparian scrub
] Freshwater marsh
I Cismontane alkali marsh
] Cismontane alkali marsh (seasonal)
j Non-native grassland
Eucalyptus woodland
Agriculture
Disturbed
Developed
HGURE 3
Location of
Restoration/Mitigation Areas
t 0 Feet IOOO 2000
wetland functional analysis was prepared for the site to rate the wetland functions and
values of the existing wetlands to be impacted and the anticipated wetland functions and
values to be gained after implementation of the mitigation effort (Attachment 2).
The overall habitat value of the mixed riparian vegetation along the major creeks is
moderate to high. Surveys indicate vegetation along Calavera Creek supports several
individuals of the federally listed least Bell's vireo. The vegetation where the vireos were
sighted is predominantly mule fat {Baccharis salicifolia) with a western sycamore
(Platanus racemosa) overstory. The riparian scrub and riparian woodland vegetation
communities throughout the area have been colonized by non-native species, including
giant reed (Arundo donax), castor bean (Ricinus communis), and pampas grass (Cortderia
jubata). The edges in particular have been invaded by fennel (Foeniculum vulgare) and
mustard (Brassica spp) from the adjacent agricultural lands.
The cismontane alkali marsh and seasonal cismontane alkali marsh found on the site are
characterized by the presence of wetland species, including spiny rush (duncus acutus ssp.
leopoldii), yerba mansa (Anemopsis caifornica), salt grass (Distichlis spicata), spikerush
(Eleocharis sp.), and alkali heath (Frankenia salina). The seasonal marsh is generally
located at the upper end of small erosional drainages on the site adjacent to Little Encinas
and Agua Hedionda Creeks. The cismontane alkali marsh is significant on the site
because it supports spiny rush, which is a CNPS List 4 species.
Both the mixed riparian vegetation and cismontane marsh in the area are supported by
water flows conveyed by the creeks and surface runoff. Agricultural uses have altered the
natural hydrology on portions of the project site. Areas that historically supported
drainages are now routinely disked. In many of these areas subsurface flows support
disjunct patches of hydrophytic vegetation.
Responsibilities
A. Owner/Project Proponent
The owner/project proponent shall provide detailed construction drawings, phasing plans,
accurate timelines, and written project specifications in conformance with this plan. The
owner/project proponent shall be responsible for funding all aspects of the project
including implementation, long-term maintenance, and any needed remedial actions as
determined by the U.S. Fish and Wildlife Service (USFWS), California Department of
Fish and Game (CDFG), U.S. Army Corps of Engineers (USAGE), and City of Carisbad.
The project proponent shall implement the mitigation measures outlined in this report
prior to or concurrent with the impacts.
6
B. Project Biologist
The project biologist will be an individual or team of individuals with a minimum of two
years' experience in riparian community restoration. The project biologist will be
retained during the project to perform the following tasks and be responsible for
implementing the restoration plan in accordance with its specifications:
• Consult with the contractor on any activities that may be disruptive to the mitigation.
• Attend pregrading and preconstruction meetings to consult with the owner/project
proponent and grading contractor and to educate the contractors on restoration goals
and habitat sensitivity.
• Monitor long-term maintenance activities of the mitigation area as defined herein.
• Oversee and perform the required monitoring and reporting in accordance with the
procedures established in this plan.
C. Plant Supplier
The native plant supplier may be the project biologist or a qualified native plant nursery.
The plant supplier must have at least two years' experience in propagating native plants.
• The plant supplier will produce properly aged plants in one-gallon containers ready
for outplanting.
• All plants will be produced from seed or cuttings collected on or adjacent to the site
and inoculated with mycorrhizae.
D. Seed Supplier
The seed supplier, who may also be the project biologist, must have at least two years'
experience collecting riparian seeds for restoration projects.
• Only species specified by the project biologist will be collected.
• Seed will be collected from the project site, whenever possible. The range of seed
collection will be limited to within a radius of 10 miles of Calavera Creek.
• The seed supplier must guarantee the purity of the collected seed.
Revegetation
Mitigation for impacts to riparian scrub, woodland, forest and cismontane alkali marsh
will include the creation of a functioning southern willow scrub, freshwater marsh, and
alkali marsh communities in restoration areas along Calavera and Little Encinas Creeks.
A. Wetland Creation and Restoration
1. Goal of Mitigation
The purpose of this wetland creation and enhancement is to replace functions and habitat
values lost by impacts to wetlands and non-wetland jurisdictional waters from the
proposed project. The quality of the created habitat will exceed that of the existing
wetland habitat. This proposed mitigation would provide for a net increase in weriand
acreage and an increase in habitat values beyond extant conditions.
2. Types of Habitat to Be Created
Impacts to jurisdictional wetiands and non-wetiand jurisdictional waters will be mitigated
by the ultimate creation of 10.7 acres of wetiand/riparian vegetation along Calavera and
Littie Encinas Creeks. Three habitat types will be established: southern willow scrub,
freshwater marsh, and alkali marsh. Southern willow scrub is a riparian community found
along major drainages but occurs in small drainages as well. Typical southern willow
scrub species occurring on the project site include arroyo willow (Salix lasiolepis), black
willow (Salix gooddingii), mule fat, western sycamore, western ragweed (Ambrosia
psilostachya), blue elderberry (Sambucus mexicana), and others. Freshwater marsh is on
the site and is comprised of cattail (Typha sp.). Alkali marsh is a community that is
adapted to saline/alkaline soils that are maintained by wet winter/spring and dry
summer/fall conditions. Plant species that occur in this habitat type on the site include
spiny rush, yerba mansa, and saltgrass.
Enhancement and creation will be accomplished by widening and lowering the existing
floodplain of Calavera Creek up to an additional 150 feet. Additional wetlands would be
created in disturbed upland areas on Little Encinas Creek. Native species will be
introduced using rooted cuttings and seeds, as well as nursery-grown container stock.
3. Functions and Values of Habitat Created
A detailed description of the wetland functions anticipated after the mitigation site is
successful is provided in Attachment 2. The proposed wetland mitigation would provide
cover, nesting, and foraging opportunities for many of the local wildlife species including
birds, insects, amphibians, and mammals. In particular, this restoration project will
replace atypical least Bell's vireo habitat with southern willow scrub of higher quality.
The created habitat (see Figure 3) offers an improved opportunity for breeding with less
noise. This created southern willow scrub will also augment cuiTent vireo habitat located
to the west in Agua Hedionda Creek.
4. Time Lapse
Planting and seeding will be limited to October 15 to June 1 in order to coincide with
appropriate weather conditions. Establishment of a functioning southern willow scrub,
freshwater marsh, and alkali marsh community is expected to take approximately four to
five years.
5. Final Success Criteria
The mitigation areas will be monitored for at least five years following the completion of
the installation of all plant materials. Each year of the monitoring period, the mitigation
sites will be assessed using two methods; standard success criteria and the functional
evaluation accepted by the U.S. Army Corps of Engineers (Stein 1999). Standard success
criteria are based on measurements of vegetation cover, species composition, and species
diversity. The functional-based mitigation success criteria are based on both interim and
final goals that are assessed according to hydrologic, biogeochemical, and biologic
conditions of the mitigation areas. Interim goals will be used to assess progress and will
provide information for recommendations for remedial actions and adaptive management
strategies. Final goals are used to certify the acceptance of the mitigation or the need for
contingency measures. Mitigation monitoring may extend beyond the initial five-year
period until the sites have achieved the ultimate success criteria, or until the U.S. Army
Corps of Engineers and Califomia Department of Fish and Game determine that
monitoring is no longer needed, or altemative mitigation solutions are adopted by the
resource agencies.
The success of the wetland mitigation is determined using criteria based on the general
site characteristics and on the functional condition of the mitigation areas. General site
conditions such as wildlife use, diversity of native wetland plants, native plant cover,
resilience, and presence of wetland indicators will be evaluated at each mitigation area.
Functional conditions are assessed to determine the functional capacity of the specific
wetland resource being created. The conditions evaluated include habitat characteristics,
hydrologic regime, topographic complexity, and biogeochemical processes (Stein 1999).
Each year the mitigation areas will be evaluated and scores assigned to each of the
success criteria assessed. These values are then compared to the standard success criteria
goals and the functional interim and final goals (Tables 2 and 3, respectively).
TABLE 2
STANDARD SUCCESS CRITERIA
Year Native Vegetation Cover Species Composition Species Diversity
1 100% native —
2 50% 95% native 100% target species
3 80% 95% native 100% target species
4 90% 95% native 100% target species
5 90% 95% native 100% target species
TABLE 3
FUNCTIONAL SUCCESS CRITERU.
Evaluation Criteria Interim Target Ultimate Target
Structural diversity 0.4 0.8
Spatial diversity 0.6 0.8
Exotic vegetation 0.8 1.0
Hydrologic regime 1.0 1.0
Floodprone area 0.8 1.0
Topographic complexity 0.5 0.8
Biogeochemistry 0.6 0.8
SOURCE: Stein 1999.
In addition to the above success criteria, all wetland types to be created, restored, or enhanced
shall meet the three-parameter wetlands criteria that include hydrophytic vegetation, hydric soils,
and natural hydrology. Alkali marsh areas shall exhibit the same range of electro-conductivity as
the areas to be impacted.
6. Target Hydrological Regime
Agricultural development on both sides of Calavera Creek have narrowed and confined
the creek and vegetation to a narrow strip. The mitigation area adjacent to the channel
will be excavated and widened. Vegetation in the creek channel currentiy receives surface
runoff and water flow from Lake Calaveras through Calavera Creek. This channel will
likely receive additional mnoff as local development occurs. In addition to surface flow,
groundwater, located within 10 feet of the surface, will facilitate revegetation.
The Little Encinas Creek mitigation area is located in a low flow detention basin east of
College Boulevard Reach A and south of Reach 4a of Cannon Road (see Figure 3). This
basin is designed to provide flood protection for a mobile home park located immediately
10
downstream. The created riparian vegetation in this basin will receive runoff from Littie
Encinas Creek.
7. Existing Functions and Values of Mitigation Area
The existing vegetation on the mitigation areas adjacent to Calavera Creek is composed
of agricultural land to the west of the creek and non-nastive ruderal habitat to the east of
the creek. The mitigation area adjacent to Littie Encinas Creek will be located on
disturbed lands. This site is dominated by weedy non-native grasses.
8. Implementation
This restoration plan will use cuttings from the local area, salvaged plants collected from
habitat impacted by the College Boulevard and Cannon Road extensions, as well as
nursery-grown container plants. The sites will be planted with native species appropriate
to southern willow scrub, freshwater marsh, and alkali marsh.
;>
a. Site Preparation
In the mitigation area on Calavera Creek, heavy equipment will be used to widen the
existing channel by approximately 200 feet west and 150 feet east of the creek. This will
create a planting area in the channel bottom within five to ten feet of the water table. In
the mitigation area on Little Encinas Creek, heavy equipment will be used to bring the
soil surface closer to groundwater. Where possible, the existing riparian vegetation will
be clearly marked to remain undisturbed by earth-moving activities. The project biologist
will be on-site during grading to ensure minimum impacts to the existing wetland
vegetation.
b. Irrigation
Precipitation in southern California is often irregular with on average one out of every
three years experiencing drought. Restoration projects dependent on natural rainfall can
be severely hampered by poor rainfall years. To improve restoration success and provide
greater flexibility in project implementation, an automated overhead sprinkler irrigation
system will be installed prior to planting.
c. Container Plants
Willow, Cottonwood, and mule fat cuttings will be taken from trees within a 10-mile
radius of the mitigation site for use in the creation of the southern willow scrub habitat.
These cuttings will be rooted in one-gallon containers for planting at the wetland creation
site. San Diego sagewort (Artemisia palmeri) and blue elderberry will be grown from
locally collected seeds. Cuttings and container plant densities are presented in Table 4.
Installation of native plants will begin after grading of the wetland habitat restoration
area. Plant installation will be limited to the months of October 15 through June 1.
11
TABLE 4
RIPARIAN SCRUB PLANTING DENSITIES
Species Number per Acre Size
Mule fat 200 one-gallon
Baccharis salicifolia
Arroyo willow
Salix lasiolepis
100 one-gallon
Black willow 100 one-gallon
Salix gooddingii
Red willow 100 one-gallon
Salix gooddingii
Westem sycamore
Platanus racemosa
75 one-gallon
Blue elderberry
Sambucus mexicana
50 one-gallon
California rose 50 one-gallon
Rosa californica
Fremont Cottonwood 25 one-gallon
Populus fremontii
Salvaged plants from the alkali marsh impact areas, nursery grown stock, and seed
collected from remaining alkah marsh areas within a 10-mile radius of the project will
form the base line vegetation for this habitat type (Table 5). The alkali marsh species will
be installed in appropriate areas of the mitigation sites where the driest conditions are
anticipated during the summer and fall months. Spiny rush, saltgrass, and yerba mansa are
the primary species to be used. Other alkali marsh species may be introduced in low
numbers, such as alkali heath and alkali weed (Cressa truxillensis). A total of 0.54 acre of
this habitat type will be created.
12
TABLE 5
PLANT MATERIALS AND DENSITIES
FOR ALKALI MARSH AREAS
Species Container Size
Pounds/Acre
Seed
Number of
Plugs/Acre
Alkali weed
Cressa truxillensis
Seed or plugs or
salvage plants
1.0 100
Alkali heath
Frankenia salina
Seed or plugs or
salvaged plants
1.0 25
Spiny rush
Juncus acutus
Seed or plugs or
salvaged plants
1.0 75
Saltgrass
Distichlis spicata
Seed or plugs or
salvaged plants
1.0 75
TOTAL 4.0 275
Salvaged cattail tubers and collected seed will be used to create the freshwater marsh
areas within the mitigation sites. Freshwater marsh habitat will be created in the wettest
portions of the mitigation sites. A total of 0.15 acre of this habitat will be created.
d. Seed Collection and Application
Seed collection will begin at least six months prior to restoration implementation.
Following installation of salvaged and container plants, the willow scrub mitigation areas
will be seeded. Two different seed mixes will be prepared for the project site. One
species mix will be used for low-lying areas that will eventually become riparian
understory and a second upland mix will be used for berm slopes and transitional areas.
To prevent disturbance of transplants, the riparian understory seed mix will be applied by
hand. The upland seed mix may be either hand seeded or hydroseeded as directed by the
project biologist. Target species and application rates for both seed mixes are included in
Table 6. Only the transitional slopes adjacent to the freshwater marsh and alkali marsh
areas will be seeded.
13
TABLE 6
RIPARIAN AND TRANSITIONAL AREA SEED MIXES
Species Pounds/Acre Suggested %Purity/%Germination
Arroyo willow
Salix lasiolepis
Mugwort
Artemisia douglasiana
Mule fat
Baccharis salicifolia
Western ragweed
Ambrosia psilostachya
Tarragon
Artemisia dracuhculus
Blue elderberry
Sambucus mexicana
Califomia buckwheat
Eriogonum fasciculatum
California sagebrush
Artemisia califomica
Purple needlegrass
Nassella puichra
Giant ryegrass
Leymus condensatus
Riparian Seed Mix
2 N/A
1 , 10/50
3 2/20
2 85/25
1 10/50
Transitional Area and Slope Mix
2 95/20
3 10/65
2 15/50
3 70/60
0.25 70/80
B. Buffers
Buffer areas will be provided adjacent to preserved portions of Calavera Creek and Little
Encinas Creek, including the proposed mitigation sites. The buffers are composed of a
mixture of native and non-native habitat types (see Figure 3). Buffer distances are
anticipated to range from a minimum of 100 feet to several hundred feet from the edge of
the wetland habitat, depending on the location. Edge effects are anticipated to be very
limited given the size and location of buffer areas adjacent to the mitigation areas and
preserved portions of the creeks. These large buffer areas also eliminate the need for
barriers to be installed. Human intmsion into the mitigation areas is not anticipated to be
common given the large natural open space areas adjacent to the sites. However, to ensure
that the purpose of the mitigation areas is understood by people using the natural open
space system, signage will be placed along the edge of the wetiand areas stating that these
areas have been installed to create native habitat for plant and wildlife species.
14
C. As-built Plan
Within 45 days of the completion of mitigation implementation, an as-built plan will be
submitted to the City of Carisbad, CDFG, and USAGE. This plan will include
implementation dates, plant numbers and locations, and any significant problems
encountered or if changes are needed to be made in the field during implementation of the
final restoration plan, to determine if the mitigation project has been built as proposed.
Maintenance and Monitoring
The objectives of the maintenance and monitoring program are to ensure successful
habitat establishment and development of an information base, which documents the
maintenance and monitoring efforts. To achieve these objectives, the project biologist
will observe and direct restoration implementation, maintenance, and monitoring
activities.
The monitoring and maintenance period will begin immediately upon completion of plant
installation and will last for a period of at least five years, as presented in Table 7.
Additional maintenance and monitoring may be required beyond the initial five years if
performance/success criteria for the mitigation site are not met. The maintenance program
will ensure that debris removal, weed control, replanting and reseeding, site protection,
and other tasks are adequately performed. Maintenance measures will be conducted as
outlined below for all restoration and enhancement areas.
TABLE 7
FIVE-YEAR MAINTENANCE AND MONITORING SCHEDULE
Tasks Year 1 Year 2 Year 3 Year 4 Year 5
Weeding Quarterly Quarterly Quarterly Biannually Biannually
Trash removal Monthly Quarterly Quarterly Quarterly Quarterly
Qualitative monitoring Monthly Monthly Quarterly Quarterly Quarterly
Quantitative monitoring None Spring Spring Spring Spring
A. Implementation Monitoring
The mitigation monitoring period will begin with initial site grading and will last for at
least five years following completion of planting. To ensure that conditions of this
restoration plan are adhered to, all implementation activities will be monitored and
recorded by the project biologist. The biologist will be available on-site during
15
revegetation implementation to assist in making necessary plan modifications so the work
may proceed. Records will include dates of translocation of salvaged species, container
plantings, and seeding. These will be included in the first annual repoit.
B. General Maintenance Procedures
General maintenance will begin following the installation of all plant materials.
Maintenance tasks are anticipated to continue for five years.
1. Vegetation Clearing and Trash Removal
Pruning of any native vegetation or removal of dead wood and leaf litter shall not be
allowed in the revegetation areas. Trash will be removed from the sites by hand on a
monthly basis for the duration of the first year and quarterly thereafter. Trash consists of
all man-made materials, equipment, or debris left within the restoration area that is not
serving a function related to revegetation.
2. Weed Control
Weed control will continue throughout the five-year monitoring period. Utility easements
adjacent to or within the restoration areas will be included in weed control activities for
the project. Hand weeding or other weed control methods will be performed by
maintenance workers familiar with and trained to distinguish weeds from native species.
Dethatching will be performed on an as-needed basis. During the first year, weeding will
be performed quarterly (or more often as determined by the project biologist) to keep
weeds from producing seeds and to control weed competition during the establishment
period of native plants. Weed control will continue quarterly for years two and three and
twice a year or as needed in years 4 and 5.
Weeds will be killed or removed before they set seeds. Appropriate weed control measures
will be implemented under the direction of the project biologist. A list of exotic species
anticipated on the site is presented in Table 8. In the event that additional invasive species
are encountered, the project biologist shall refine control measures to address the problem.
16
TABLE 8
ANTICIPATED EXOTIC SPECIES
Scientific Name Common Name
Arundo donax Giant reed
Cynara cardunculs Artichoke thistle
Brassica nigra Mustard
Cortaderia selloana Selloa pampas grass
Erodium sp. Filaree, storksbill
Avena barbata ' Wild oats
Foeniculum vulgare Sweet fennel
Nicotiana glauca Tree tobacco
Ricinus communis Castor bean
Raphanus sativus Wild radish
3. Irrigation
The irrigation will be applied at the discretion of the project biologist. The irrigation
schedule will vary depending on weather patterns. Although the irrigation systems will
be maintained throughout the five-year maintenance period, the addition of supplemental
water to the mitigation areas will be initially discontinued after the second year to
determine if "natural" hydrologic conditions are sufficient to support the mitigation
habitat.
4. Plant Maintenance
One goal of the habitat mitigation is to establish native plant cover throughout the
mitigation site. Variations in site conditions will result in a mosaic of vegetation growth
that is similar to undisturbed habitats. Native plant materials will be maintained on the
site to minimize the size and distribution of bare areas. As such, barren areas greater than
one-meter-square in portions of the mitigation site where plant growth is expected shall
be replanted with appropriate native species to create the desired vegetation cover.
C. Qualitative Monitoring
Evaluating plant health and identifying and correcting problems are necessary for
ensuring successful vegetation establishment. The site will be monitored weekly during
site preparation, monthly for the first two years, and quarterly for the remainder of the
project. The project biologist will review the restoration areas to examine transplant
vigor, and exotic plant encroachment. The biologist will document the findings and make
recommendations for remedial actions, if necessary.
17
A list of plant and wildlife species observed on the restoration site will be compiled
during each qualitative monitoring visit. A list of plant species present and a description
of wildlife (including least Bell's vireo) use will be included with each annual report.
The development of hydrologic and biogeochemical functions at the mitigation sites will
be assessed qualitatively. Hydrologic functions (e.g., hydrologic regime, characteristics of
the flood prone area, and topographic complexity) will be assessed using the
methodology approved by USAGE (Stein 1999). Biogeochemical processes will be
assessed qualitatively through observations of the development of vegetation cover and
build up of leaf litter, debris, and organic detritus at the mitigation sites, according to the
approved methodology (Stein 1999).
D. Quantitative Monitoring
Quantitative monitoring will be performed to measure development of vegetation in the
restoration and enhancement areas and to document that the restoration areas achieve the
success criteria as defined by the performance standards.
Beginning in year 2, permanent vegetation sampling stations will be established within
each restoration site to measure year-to-year changes in herb, shrub, or tree cover, and
diversity following the protocol of the Califomia Native Plant Society Plant Communities
Project (Sawyer and Keeler-Wolf 1995).
The CNPS sampling method is based on a 50-meter point transect centered on a 5x50-
meter plot. Using this method, vegetation is sampled by the point method at 0.5-meter
intervals along the 50-meter transect to determine cover. The surveyor will note the
species encountered and classify its height (i.e., herb, shrub, or tree) at each interval. In
addition, each shrub-sized individual of each perennial species growing in the 5x50-meter
plot will be counted to determine shrub presence and diversity. All annuals present in the
5x50-meter plot will also be noted.
Sampling will be conducted in the spring so that the maximum species diversity will be
recorded. At least three plots per mitigation area will be used to determine vegetation
cover, plant community composition, and plant diversity. A photograph will be taken
from each sample endpoint (toward the plot) each time the site is monitored to record the
progress of mitigation over the monitoring period.
E. Monitoring Reports
Annual reports summarizing monitoring results will be submitted to CDFG, USAGE, and
the City of Carlsbad by the project biologist within 90 days of data collection. The
quantitative report will include survey methods, data summary analysis, performance
18
standards comparison, discussion, remedial action discussion, recommendations, and
photodocumentation. Each annual report will compare findings of the current yeai- with
those in previous years.
F. Performance Standards
Restoration of the Calaveras Creek mitigation areas will be considered successful when
both the standard and functional performance criteria have been met. If the minimum
levels for any one of the measurements (see Tables 2 and 3) are not achieved in any year,
the project biologist will implement remedial actions, such as replanting container stock,
to reach the following year's expected levels. In order to meet the performance standards,
the habitat must sustain itself for a minimum of one year (meeting the fifth-year
performance standards) in the absence of significant maintenance measures any year
during the five-year monitoring period. Significant maintenance includes replanting and
eradication of weed infestations. Other maintenance measures, such as minor weed
control, may continue until the end of the monitoring period.
1. Tolerance of Weeds
The cover of non-native annual grasses and herbs, such as brome grass or filaree, as
identified by the project biologist, will be no more than 5 percent of the total vegetation
cover. No invasive exotic perennials, such as giant reed, pampas grass, and tamarisk, will
be permitted on the revegetation sites.
2. Remedial Measures
If performance criteria are not achieved at the end of the fifth year, the permittee will
consult with CDFG, USAGE, and the City of Carisbad to determine whether the
mitigation effort is acceptable. The owner/project proponent understands that failure of
any significant portion of the initigation area may result in a requirement to replace or
revegetate that portion of the site.
G. Notification of Completion
At the end of the fifth year, a final report will be submitted to the resource agencies
evaluating the success of the mitigation. The report will make a determination of whether
the requirements of the mitigation plan have been achieved.
At the conclusion of the five-year monitoring period, or at such time the project has
achieved the performance standards, the project biologist shall inform the owner/project
proponent, CDFG, USAGE, and the City of Carlsbad. A site review will be scheduled for
19
all parties to review the revegetated sites. Upon confirmation of project success, the
agencies shall release the owner/project proponent of all obligations.
References Cited
Sawyer, J. O., and T. Keeler-Wolf
1995 A Manual of California Vegetation. California Native Plant Society.
Sacramento.
Stein, E.
1999 Function-Based Performance Standards for Evaluating the Success of Riparian
and Depressional/Emergent Marsh Mitigation Sites. Prepared for the U.S. Army
Corps of Engineers, Los Angeles District - Regulatory Branch. May.
20
ATTACHMENTS
r
ATTACHMENT 1
REPLY TO
ATTENTION OF;
Office of the Chief
Regtilatory Branch
DEPARTMENT OF THE ARMY
LOS ANGELES DISTRICT, CORPS OF ENGINEERS
SAN DIEGO FIELD OFFICE
16885 WEST BERNARDO DRIVE, SUITE 300A
SAN DIEGO, CALIFORNIA 92127
May 15, 2002
Calavera Hills U, LLC and
Mr. Brian MiUich
2727 Hoover Avenue
National City, CA 91950
City of Carlsbad
Mr. David Haitser
1635 Faraday Avenue
Carlsbad, CA 92008
Dear Messrs. MOich and Hauser:
Enclosed you will find a signed copy of your Departinent of the Army Pennit (File # 2001-
00215-RLK). Please retain this copy for yotir files.
Thank you for participating in our regulatory program. If you have any questiorts, please
contact Mr. Russell L. Kaiser at (213) 452-3293.
Sincerely,
Mark F. Sudol, D.Env.
Chief, Regulatory Branch
Enclosures
|IH^i^|!.|kC>^^\>•^
LOS ANGELES DISTRICT
U.S. ARMY CORPS OF ENGINEERS
DEPARTMENT OF THE ARMY PERMIT
Permittee:
Pennit Number:
Calavera Hills II, LLC and
Mr. Brian Millich
2727 Hoover Avenue
National City, CA 91950
200100215-RLK
City of Carlsbad
Mr. David Hauser
1635 Faraday Avenue
Carlsbad, CA 92008
Issuing Office: Los Angeles District
Note: The term "you" and its derivatives, as used in this permit, means the permittee or any
future transferee. The term "this office" refers to the appropriate district or division office of the
Corps of Engineers having jurisdiction over the permitted activity or the appropriate official
acting under the authority of the commanding officer.
You are authorized to perform work in accordance with the terms and conditiorts specified below.
Project Location: The proposed project is located iri the northeast quadrant of the City of
Carlsbad in San Diego Coimty, Califorrtia.
Project Description: The project consists of three major components: (1) Cortstruction of up to
781 residential units as well as associated infrastructure, commtmity facilities and natural open
space within the Calavera HUls Master Plarmed Conmiuruty; (2) Cortstruction of the extension
of College Boulevard from its existing northem tenninus within the Calavera HUls Community
to its existing southem terminus just northerly of El Camino Real, as well as the extension of
Carmon Road from its existing westem terminus at El Camino Real to its proposed intersection
with CoUege Boulevard; and (3) Constmction and operation of two flood control basins (Basins
BJB and BJ) with a storage capacity of 49 acre-feet and 48 acre-feet, respectively. The berms
necessary for the flood control basins are integrated into the culverted roadway crossings
(Figiure 1).
Project Authorization: You are authorized to discharge fill in 0.70 acre of waters of the Uruted
States (U.S.), including Calavera Creek, Aqua Hedionda Creek, Little Encinas Creek, and other ,
cormected urmamed tributary waters and/or wetlands to constmct the project described above.
Of the total impacts on waters of the U.S., 0.64 acre would be permanent and 0.06 acre would be
temporary. Of the permanent impacts, 0.28 acre would occur on wetland waters and 0.36
would occur on non-wetland waters of the U.S. AU temporary impacts would occvtr on non-
wetland waters of the U.S. The following table sets forth the specific activities and impacts
associated with the proposed activity and Figure 4 identifies the waters of the U.S. and the
impact areas.
PROIECT IMPACTS ON WATERS OF THE U.S.
Project
Component
Ripa
Wood
rian
land
Freshwater Marsh Cismontane
Alkali Marsh
TO'
Wetlanc
fAL
1 Waters
TOTAL
Non-Wetland Waters
Perm Temp Perm Temp Perm Temp Perm Temp Perm Temp
Calavera Hills
Phase n
0.1 0.1 0.2 0.0
Cannon Rd.
Reach 3
0.08 0.08 0.0 0.0
College Reach A 0.04 0.05 0.09 0.03 0.06
College Reach B 0.0 0.0
College Reach C 0.0 0.0
College / Cannon
Intersect
0.01 -0.01 0.13 0.0
Detention
Basins
0.0 0.0
TOTAL 0.05 0.0 0.05 0.0 0.18 0.0 0.28 0 0.36 0.06
Permit Conditions.
General Conditions:
1. The time limit for completing the authorized activity ends on Jvdy 1, 2004. If you find that
you need more time to complete the authorized activity, submit your request for a time extension
to this office for consideration at least one month before the above date is reached.
2. You must maintain the activity authorized by this permit in good condition and in
conformance with fhe terms and conditions of this permit. You are not reUeved of this
requirement if you abandon the permitted activity, although you may make a good faith transfer
to a third party in compUance with General Condition 4 below. ShoiUd you wish to cease to
maintain the authorized activity or should you desire to abandon it without a good faith transfer,
you must obtain a modification from this permit from this office, which may require restoration of
the area.
3. If you discover any previously unknown historic or archeological remains whUe
accomplishing the activity authorized by this permit, you must immediately notify this office of
what you have fotmd. We wiU initiate the Federal and state coordination required to determine if
fhe remains warrant a recovery effort or if the site is eUgible for listing in the National Register of
Historic Places.
4. If you seU the property associated with this permit, you must obtain the signature of the
new owner in the space provided and forward a copy of the permit to this office to vaUdate the
transfer of this authorization.
5. If a conditioned water quaUty certification has been issued for your project, you must
comply with the conditions specified in the certification as special conditions to this permit.
6. You must aUow representatives from this office to inspect the authorized activity at any
time deemed necessary to ensure that it is being or has been accomplished with the terms and
conditions of your permit.
Special Conditions:
1 Pre-Cnnstrurtinn Rpquirements:
1.1 Thirty days prior to the discharge of fUl in waters of the U.S., including wetlands, the
Pennittee shaU submit for Corps approval a Pre-Construction Operations (CO) Plan. The Pre-CO
plan shaU include:
1.1.1 Proposed constmction timeline and sequencing.
1.1.2 Pre-constmction surveys defining project boimdaries with respect to avoidance of
Section 404 Resources (e.g., waters of the U.S., biological and cultural).
1.1.3 Site plan delineating boundaries for staging, fueling and storage areas. Storage areas
shaU include sites for spoU and borrow materials. Staging, fueling and storage areas
shaU not be located within 100 feet of waters of the U.S.
1.1.4 Measures to be taken to prevent an unpermitted discharge(s) of fUl into Waters of the
U.S. may include use of sUt nets, hay bales and other Best Management Practices
(outside of Waters of the U.S.), including use of emergency spUl kits.
1.1.5 Photographs documenting site conditions, including work limits and resource exclusion
areas. Photographs shaU show demarcated (staked/roped) constmction areas, and
exclusion areas, including waters of the U.S., cultural resources, and open space areas.
In addition, the Pennittee shaU:
1.1.5.1 Retain a Corps approved biologist to monitor and inspect aU on-site activities. The CO
Plan shaU identiJFy the biologist's name, address, phone nuinber, emaU address and
experience/credentials. The biologist shaU review, oversee, morutor, and/or inspect:
1.1.5.1.1 Grading and site plans;
1.1.5.1.2 Installation of rope to demarcate constmction work and open space areas;
1.1.5.1.3 All grading, excavation and ground (and non-ground) disturbance activities in (or
near) Waters of the U.S., and
1.1.5.1.4 Compliance of avoidance measures for open space areas.
1.1.5.1.5 Furthermore, the Corps approved biologist shall:
1.1.5.1.5.1 Be empowered to halt constmction and contact Corps, Regulatory Project Manager
if he/she believes the terms and conditions of the authorization are being violated,
with non-compliance reported to the Corps within one hour of detection; and
1.1.5.1.5.2 Implement and morutor the mitigation program.
1.1.5.2 Retain a Corps approved cultural resource specialist to monitor and inspect all on-site
activities, near CA-SDI-9092, CA-SDI-9093/9094, CA-SDI-9615, CA-SDI-15069, CA-SDI-
5434, SA-SDI-5436, and Temp 5. The CO Plan shaU identify tiie cultiiral resource
specialist's name, address, phone number, email address and experience/credentials.
The cultural resource specialist shall review, oversee, morutor, and/or inspect:
1.1.5.2.1 AU activities, investigations, and reporting requirements for Section 106 Compliance
witii CA-SDI-9092, CA-SDI-9093/9094, CA-SDI-9615, CA-SDI-15069, CA-SDI-5434,
SA-SDI-5436, and Temp 5 sites. No work shaU be performed within a 100-foot
radius of CA-SDI-9092, CA-SDI-9093/9094, CA-SDI-9615, CA-SDI-15069, CA-SDI-
5434, SA-SDI-5436, and Temp 5 except as aUowed in Section 2.4. In addition, the
monitor shaU be onsite during aU ground disturbance activities.
1.1.5.2.2 Furthermore, the Corps approved cultural resource specialist shaU:
1.1.5.2.2.1 Be empowered to halt constmction and contact Corps, Regulatory Project Manager
. if he/she beUeves the terms and conditions of fhe authorization are being violated,
with non-compliance reported to the Corps within one hour of detection; and
1.1.5.2.2.2 Implement and monitor the mitigation program, if warranted.
1.2 The Corps may conduct onsite field investigations prior to and during constmction
activities to inspect for compUance with aU conditions listed herein.
2 Mitigation Rpquirements:
2.1 The Permittee shaU comply witii tiie Biological Opinion (FWS-SDG-1597.4, dated March
14, 2002; aU terms and conditions are non-discretionary, pp. 31-33).
2.2 The Permittee shaU post a Performance Bond (or bonds) for 120% of the anticipated
costs of the mitigation and monitoring associated with the project.
2.2.1 The bonding company must appear on the Department of Treasury Circular 570,
Companies Holding Certificates of Authority as Acceptable Sureties on Federal Bonds
and Acceptable Reinsuring Companies. For a cunent list of Treasury-authorized
companies, write or caU the Surety Bond Branch, Financial Management Services,
Departinent of tiie Treasury, Washington D.C. 20227; (202) 874-6850.
2.2.2 The performance bond(s) shaU be conditioned such that if the Permittee defaults on the
mitigation requirements stated in the special conditions herein, the bonding company
shaU assume all responsibiUty for the mitigation requirements of this pennit.
2.2.3 The performance bond(s) shaU be released only upon a determination by the Corps that
successful mitigation has been completed.
2.2.4 The Perrruttee shall submit a draft bond with an itemized costs Ust for the mitigation
components relating to fhe initial phase of work (Calavera HUls Phase II, College
Reaches B and C, detention basin BJB and Carmon Reach 3) to the Corps for approval at
least five days prior to initiating waters/wetlands impact authorized by this permit. A
second bond with an itemized costs list for the mitigation components relating to the
second phase of work (College Reach A and detention basin BJ) shaU be submitted at
least 60 days prior to commencing work on College Reach A or detention basin BJ.
2.2.5 The Permittee shall submit the final bond for the amount approved by the Corps for the
initial phase of work within 30 days of initiating waters/wetlands impact authorized by
this pemut. In the event rrutigation costs exceed or otherwise deviate from the amount
of the performance bond (120% of anticipated cost of mitigation and monitoring)
originaUy posted, the Permittee shaU revise the performance bond to reflect tme cost
(based on fhe final Corps-approved mitigation and monitoring plan). The Permittee
shall submit the final bond for the amount approved by the Corps for the second phase
of work at least 15 days prior to commencing work on CoUege Reach A or detention
basin BJ.
2.3 The Permittee shall abide by the terms and conditions of the Mitigation Guidelines &
Monitoring Requirements outlined in the Habitat Restoration and Morutoring Plan for the City
of Carlsbad Bridge & Thoroughfare District No. 4, the Calavera HUls Project, and the Detention
Basins Project in Carlsbad, Califomia, dated AprU 3, 2002, as approved and revised by the
Corps, and hereafter referred to as the "Plan" as follows:
2.3.1 The Permittee shaU finalize the Plan within 90 days of issuance of this permit. The Final
Plan shaU incorporate Corps comments on the draft as weU as the final plans and
specifications for each of the different mitigation sites.
2.3.2 The Permittee shaU establish and maintain the open space conservation areas for project
riparian mitigation areas associated with each of the two phases of impacts. The
Pennittee shaU record conservation easements, which shaU run with the land, obUgating
the Permittee or their successor or assigns to maintain aU mitigation (creation,
enhancement and preservation) area as natural open space in perpetuity. The Permittee
shaU receive, written approval from the Corps for the easement language prior to it
being recorded. The Corps-approved conservation easement for the area underlying the
irutial phase of mitigation shaU be submitted to Corps-approved recipient of the
easement no later than 90 days from the date of issuance of the permit. The form of
conservation easement for the area underlying the second phase of mitigation shaU be
approved by the Corps at least 30 days prior to the commencement of work on College
Boulevard Reach A and detention basin BJ. The Corps-approved conservation easement
for the area underlying the second phase of mitigation shaU be submitted to the Corps-
approved recipient of the easement prior to commencing work on College Reach A or
detention basin BJ.
2.3.3 The Permittee shall create 10.7 acres of vegetated riparian habitat, as presented in the
Plan. Of this total, 8.1 acres wiU consist of riparian woodland, 1.7 acre wiU consist of
riparian scmb, 0.7 acre of cismontane alkali marsh, and 0.2 acre of non-wetland waters,
as described in the Habitat Restoration and Monitoring Plan for the City of
Carlsbad Bridge & Thoroughfare District No. 4, the Calavera Hills Project, and
the Detention Basins Project in Carlsbad, California, dated April 3,2002.
2.4 The Permittee shall temporarUy avoid work in areas near potentiaUy eUgible sites for listing
under tiie National Register of Historic Places (NRHP), including CA-SDI-9092, CA-SDI-
9093/9094, CA-SDI-9615, CA-SDI-15069, CA-SDI-5434, SA-SDI-5436, and Temp 5, until tiie
Corps, in coordination with the State Historic Preservation Office, has completed the Section
106 process and a determination of findings is made. Until the process is complete, the
Perrruttee shall:
2.4.1 Place Exclusionary Fencing, five days prior to initiation of constmction, around CA-
SDI-9092, CA-SDI-9093/9094, CA-SDI-9615, CA-SDI-15069, CA-SDI-5434, SA-SDI-5436,
and Temp 5. No work shall be performed within a 100-foot radius of CA-SDI-9092, CA-
SDI-9093/9094, CA-SDI-9615, CA-SDI-15069, CA-SDI-5434, SA-SDI-5436, and Temp 5.
2.4.2 Perfonn aU further investigations, studies and mitigation, as directed by the Corps, to
determine if site(s) is\(are) eligible for listing under the NRHP. The Permittee shaU
fund aU investigations required by the Corps. For reporting purposes, the Pennittee
shaU prepare a Draft Mitigation Plan, which shaU be submitted for Corps review and
approval. FoUowing completion of the investigations, a Final Report shall be prepared
by the Permittee and submitted for Corps approval.
2.4.3 Request Corps release of the site(s), upon completion of the cultural resoiurce
investigations. Again, no constmction work shaU be conducted within the exclusion
area untU the Corps provides a letter indicating site compUance has been completed.
Once the findings of the evaluation have been determined, work efforts may be
permitted with modifications and if only aU appropriate mitigation measures are
undertaken, per 36 CFR 800.11.
2.4.4 Not perform any activities which may affect historic properties Usted, or eligible for
Usting, in the NRHP is authorized, until the District Engineer (DE) has compUed with
tiie provisions of 33 CFR Part 325, Appendbc C. The Pennittee must notify tiie DE if the
authorized activity may affect any historic properties listed, determined to be eligible
for listing, or which the Pennittee has reason to beUeve may be eUgible for Usting on the
NRHP, and shaU not begin the activity until notified by fhe DE that the requirements of
the National Historic Preservation Act have been satisfied and that the activity is
authorized.
2.4.5 Immediately suspend aU work in an area(s) where potential cultural resources are
discovered prior to or during constmction and caimot be avoided. Work wUl not
resume untU the Corps re-authorizes project constmction, per 36 CFR 800.11.
3 Pncf rrtn-jfrurtinn-
3.1 The Permittee shall submit a "Post-Constmction Operations Report" to the Corps
within 30 days from the date constmction is completed. The Post CO Report shaU include:
3.1.1 A summary of project compUance with the measures identified above (including
noncompliance and conective actions taken to achieve compUance); and
3.1.2 As-built plans of the Calavera HUls, Phase II, project development with a discussion of
any variances from the authorized Plan.
3.2 The Pennittee shall be responsible for mitigating any additional impacts to waters of the
U.S. outside the authorized constmction footprints. Additional rrutigation shall be conducted
at a ininimum ratio of 5:1. In the event that additional mitigation is required, the type of
mitigation shaU be determined by the Corps and may include enhancement, restoration,
creation, or preservation.
3.3 The Permittee shall submit monitoring reports, per the Mitigation Guidelines and
Monitoring Requirements for the Plan (Condition No. 2.3 above) for mitigation efforts
to the Corps for a minimum of five years and until such a time as the mitigation is
deemed successful by the Corps.
Further Information:
1. Congressional Authorities. You have been authorized to undertake the activity described
above pursuant to:
( ) Section 10 of tiie River and Harbor Act of 1899 (33 U.S.C. 403). ,
(X) Section 404 of tiie Clean Water Act (33 U.S.C. 1344).
( ) Section 103 of the Marine Protection, Research and Sanctuaries Act of 1972 (33
U.S.C.1413).
2. Limits of this authorization.
2.1 This permit does not obviate the need to obtain other Federal, state, or local authorizations
required by law.
2.2 This permit does not grant any property rights or exclusive privUeges.
2.3 This permit does not authorize any injury to the property or rights of others.
2.4 This pennit does not authorize interference with any existing or proposed Federal project.
3. Limits of Federal LiabUity. In issuing this permit, the Federal Govemment does not assume
any UabUity for the foUowing:
3.1 Damages to the permitted project or uses thereof as a result of other permitted or
unpermitted activities or from natural causes. '
3.2 Damages to the pennitted project or uses thereof as a result of cunent or future activities
undertaken by or on behalf of the United States in the pubUc interest.
3.3 Damages to persons, property, or to other permitted or unpermitted activities or stmctures
caused by the activity auttiorized by this pennit.
3.4 Design or constmction deficiencies associated with the permitted work.
3.5 Damage claims associated with any future modification, suspension, or revocation of this
permit.
4. ReUance on AppUcant's Data. The determination of this office that issuance of this pennit is
not conttary to the pubUc interest was made in reUance on the itiformation you provided.
5. Reevaluation of Permit Decision. This office may reevaluate its decision on this pennit at any
time the circumstances wanant. Circumstances that could require a reevaluation indude, but are
not Umited to, the foUowing:
5.1 You faU to comply with the terms and conditions of this permit.
5.2 The information provided by you in support of your pennit appUcation proves to have been
false, incomplete, or inaccurate (See 4 above).
5.3 Significant new information surfaces which this office did not consider in reaching the
original pubUc interest decision.
Such a reevaluation may result in a determination that it is appropriate to use the suspension,
modification, and revocation procedures contained in 33 CFR 325.7 or enforcement procedures
such as those contained in 33 CFR 326.4 and 326.5. The referenced enforcement procedures
provide for the issuance of an administrative order requiring you to comply with the terms and
conditions of your permit and for the initiation of legal action where appropriate. You wiU be
required to pay for any conective measure ordered by this office, and if you faU to comply with
such directive, this office may in certain situations (such as those specified in 33 CFR 209.170)
accomplish the conective measures by conttact or otherwise and bUl you for the cost.
6. Extensions. General condition 1 establishes a time Umit for the completion of the activity
authorized by this pennit. Unless there are circumstances requiring either a prompt completion
of the authorized activity or a reevaluation of the pubUc interest decision, the Corps wUl normaUy
give you favorable consideration to a request for an extension of this time Umit.
Your signature below, as permittee, indicates that you accept and agree to comply with the terms
and conditions of fhis permit.
PERMITTEE /S^^^/W. T't^fC/W S(//f DATE
PERMITTEE OM^IO U^O^/^
peeory C/T/ t^6rfi/ci^<-
DATE
This permit becomes effective when the Federal official, designated to act for the Secretary of the
Army, has signed below.
Mark F. Sudol, abrtv.
Chief, Regulatory Branch
DATE
When the stmctvures or work authorized by this permit are stiU in existence at the time the
property is transfened, the terms and conditions of this permit wiU continue to be binding on the
new owner(s) of the property. To vaUdate the transfer of this permit and the associated UabiUties
associated with compliance with its terms and conditions, have the transferee sign and date
below.
TRANSFEREE DATE
LOS ANGELES DISTRICT
U.S. ARMY CORPS OF ENGINEERS
CERTIFICATION OF COMPLIANCE WITH
DEPARTMENT OF THE ARMY PERMIT
Permit Number 2001-00215-RLK
Name of Permittee: Claavera Hills II, LLC
Date of Issuance:
Upon completion of the activity authorized by this permit, sign tiiis certification and retum
it to fhe foUowing address:
Regulatory Branch - Los Angeles District Office
ATTN: CESPL-CO-R-2001-00215-RLK
P.O. Box 532711
Los Angeles, Califomia 90053-2325
Please note that your pennitted activity is subject to a compliance inspection by an Army
Corps of Engineers representative. If you faU to comply with this permit you may be subject to
pennit suspension, modification, or revocation.
I hereby certify that the work authorized by the above referenced permit has been
completed in accordance with the terms and conditions of said permit.
Signature of Pennittee Date
Signature of Permittee Date
10
'^^^d]jdd ^i^-4%^d^^^&
PROPOSED PROJECT BIIIIWU LTIMTW —
ATTACHMENT 2
WETLAND FUNCTIONAL ANALYSIS FOR THE CITY
OF CARLSBAD BRIDGE & THOROUGHFARE
DISTRICT NO. 4, THE CALAVERA HILLS PROJECT,
AND THE DETENTION BASINS PROJECT IN
CARLSBAD, CALIFORNIA
Prepared for
PLANNING SYSTEMS
1530 FARADAY AVENUE, SUITE 100
CARLSBAD, CA 92008
1927 Fifth Avenue, Suite 200
San Diego, CA 92101-2358
619/ 308-9333 fax 308-9334
. Prepared by
GERALD A. SCHEK)
SENIOR BIOLOGIST
RECON NUMBER 3226B
OCTOBER 26, 2001
\if This document printed on recycled paper
TABLE OF CONTENTS
Introduction 1
Project Description 1
A. Project Location 1
B. Summary of Overall Project 1
Wetland Functions of Existing Jurisdictional Areas to be Impacted 5
A. Habitat Characteristics 5
B. Floodplain Characteristics 17
C. Biogeochemical Processes 18
Water Quality and Beneficial Uses 19
Wetland Functions of Habitat to Be Restored/Created 20
A. Habitat Characteristics 20
B. Floodplain Characteristics 20
C. Biogeochemical Processes 21
D. Evaluation of the Mitigation Areas 21
References Cited 22
FIGURES
1: Regional location 2
2: Vicinity map 3
TABLES
Functional Analysis Ratings for Calavera Creek 6
Functional Analysis Ratings for Littie Encinas Creek 7
Functional Analysis Ratings for Aqua Hedionda Creek 8
Functional Analysis Ratings for Jurisdictional Waters in Phase n Master
Plan Areas 9
TABLE OF CONTENTS (cont.)
PHOTOGRAPHS
1: Riparian Woodland along Calavera Creek 11
2: Location on Calavera Creek Where the Intersection of Proposed College
Boulevard and Cannon Road will Impact the Creek 11
3: Freshwater Marsh Wetiand Adjacent to Calavera Creek 12
4: Non-Wetiand Drainage in Coastal Sage Scrub 13
5: Non-Wetiand Waters Affected by Agricultural Activities 13
6: Location on Agua Hedionda Creek Where Proposed College Boulevard
Bridge wiU Impact the Creek 14
7: Riparian Woodland along Littie Encina Creek 15
Introduction
The wetland functional analysis contained in this report provides a description of the
functions and values of the existing wetiand and proposed mitigation areas. This
document has been prepared to embody the Function-Based Method for Assigning
Mitigation Ratios for Impacts to Riparian Systems (Stein 1999a). Anticipated wetiand
functions and values at the proposed mitigation sites are also discussed.
Project Description
A. Project Location
The Calavera Hills Master Plan Amendment & Bridge and Thoroughfare District No. 4 &
Detention Basin project is located in the northeast quadrant of the city of Carlsbad
(Figures 1 and 2). The 412.6-acre Calavera Hills Master Plan Phase n development area
is bounded by the Oceanside city limits along with State Route 78 (SR-78) on the north
and the southern boundary being approximately one-half mile north of the Rancho
Carlsbad Mobile Home Park. The master plan's western extent is near Carlsbad Village
Drive and the easterly boundary is just west of Calavera Lake. The College Boulevard
and Cannon Road extensions run north-south, east-west (respectively) between the
Rancho Carlsbad Mobile Home Park and the Master Plan area. The detention basins
would be located near the roads on Calavera Creek and Littie Encina Creek. Watercourses
that occur within the project area include Calavera Creek, Agua Hedionda Creek, and
Little Encina Creek.
B. Summary of Overall Project
The proposed Phase n of the Master Plan would allow for the construction of a maximum
of 781 residential units within a series of villages. Other community facilities and
infrastructure improvements to the Phase 11 Master Plan area are roads, utility lines,
drainage improvements, and other public and community facilities.
The second component of the project is the formation by the City of Carlsbad of a Bridge
and Thoroughfare District No. 4 for the extensions of College Boulevard and Cannon
Road. College Boulevard (Reaches A, B, and C) would be extended from within the
Calavera Hills Master Plan at Carlsbad Village Drive southerly to El Camino Real
(approximately 9,500 feet). The Bridge and Thoroughfare District encompasses the reach
of College Boulevard (Reach C) that lies within the boundaries of the Calavera Hills
Master Plan. Cannon Road (Reaches 3 and 4) would be extended from El Camino Real
easterly to the city of Oceanside (approximately 9,100 feet). Although the Bridge and
OCEANSIDE.
PROJECT LOCATION
CARLSBAD
(761
SAN MARCOS
ENCINITAS^
t
0 MILES 2.2
M-.jobsVi225e\graphics\regina\.cdr
4.4 FIGURE 1
Regional Location ofthe Project
i
Basin BJ
• m t
5?
Man-made pond
Master Plan Phase II
Bridge and Thoroughfare District
Detention basins
Feet 2000
FIGURE 2
Project Vicinity
Thoroughfare District funding is not expected to include Cannon Road Reach 4, it is
included in this permit application to provide the cumulative effect of the project. Final
design changes are being considered for Cannon Road Reach 4 that could further
minimize impacts to jurisdictional waters through avoidance and buffer areas. A total of
94 percent of the wetland impacts are a result of construction of these roadway links.
The design of Reaches A-C for College Boulevard and Reaches 3-4 for Cannon Road
included all grading, improvements, bridges, retaining walls, erosion control and
landscaping, drainage, and all other improvements associated with development of major
arterial roadways. Both Cannon Road and College Boulevard are shown on the City's
circulation element as major arterials within a 102-foot right-of-way (widened at
intersections). Buildout design standards for major arterials include two 12-foot travel
lanes in each direction with an 18-foot median separating the travel directions.
The third component of the project consists of the construction of two detention basins by
the City of Carlsbad to control flooding impacts within the Calavera Creek watershed.
These basins have been recommended near the northeast corner of the Rancho Carlsbad
Mobile Home Park. Basin 1 (referred to as Basin "BJB") at the northeast quadrant of the
College Boulevard/Cannon Road intersection, in its ultimate configuration, would have
an inundation area of approximately 15 acres and a storage capacity of 49 acre-feet.
Basin 2 (refened to as Basin "BJ") is located southeast of the College Boulevard/Cannon
Road intersection and would have an inundation area of approximately eight acres with a
storage volume of 48 acre-feet. The basins are part of a larger drainage plan for the area,
and are consistent with the 1994 City of Carlsbad Master Drainage Plan. The road
crossings of Calavera Creek and Little Encina Creek form the berms for the detention
basins.
Wetland Functions of Existing Jurisdictional
Areas to be Impacted
The wetland functions of most of the jurisdictional areas on the project site have been
altered due to agricultural and off-road-vehicle activities on the property. Wetiand
functions for the project site and mitigation areas were determined using the Function-
Based Method for Assigning Mitigation Ratios for Impacts to Riparian Systems provided
by the U.S. Army Corps of Engineers (Stein 1999a). This methodology compares the
wetiand functional loss at the proposed impact site with the proposed wetiand functional
gain at the mitigation site.
The criteria used to determine the wetland functions are based on characteristics of the
habitat, hydrology/floodplain, and biogeochemical processes. Habitat characteristics used
include structural diversity, spatial diversity, contiguity, and presence of invasive
vegetation. Hydrology/floodplain characteristics involve a determination of the
hydrologic regime (the source of water to a site), characteristics of the flood-prone area
(e.g., channel confinement and overbank flow), and topographic complexity of the
floodplain (e.g., presence of pits, ponds, large boulders, and rills). Biogeochemical
processes are determined from estimates of vegetation cover (roughness) and amount of
debris, leaf litter, and detritus present (organic carbon).
There are three main wetiand/riparian areas within the proposed road improvement
portion of the project; Calavera Creek, Agua Hedionda Creek, and Littie Encina Creek.
Each of these major drainage features has smaller wetland tributaries that convey local
runoff to the creeks. In a few locations, small wetland areas are adjacent to the creeks
along these tributaries. The Master Plan area also contains some small patches of wetland
along the predominately non-wetiand jurisdictional waters that drain to the north and west
away from the three major creeks. The rank given each wetland function for each major
creek and the Master Plan area with their associated adjacent wetlands and non-wetland
waters is given in Tables 1 through 4. A description of each ranked functional criteria is
provided. Non-wetland drainages are vegetated with mostly upland shrubs.
A. Habitat Characteristics
Four habitat characteristics are evaluated for riverine systems. These are structural
diversity, spatial diversity, contiguity, and presence of invasive vegetation. In addition,
other biological values are also considered (i.e., wildlife corridors).
1. Structural Diversity
The structural diversity is determined by ranking a site with respect to the presence of
different layers in the vegetation. These layers include tree, shrub, and understory.
^1
TABLE 1
FUNCTIONAL ANALYSIS RATINGS FOR CALAVERA CREEK
Function Evaluation
Criteria
Rating:
Calavera Creek
Rating:
Adjacent
Marsh Wetiands
Rating:
Adjacent
Non-wetland Waters
Structural diversity 0.8 0.6 0.2
Spatial diversity 0.8 0.4 0.2
Habitat contiguity 0.4 0.2 0.2
Invasive vegetation 0.6 0.8 0.8
Hydrologic regime 1.0 1.0 1.0
Flood-prone area 0.7 0.7 0.7
Topographic complexity 0.2 0.2 0.6
Biogeochemical processes 0.8 0.6 0.8
TABLE 2
FUNCTIONAL ANALYSIS RATINGS FOR LITTLE ENCINAS CREEK
Function Evaluation
Criteria
Rating:
Littie Encinas
Creek
Rating:
Adjacent Marsh
Wetlands
Rating:
Non-wetland
Waters
Structural diversity 0.8 0.6 0.2
Spatial diversity 0.8 0.4 0.2
Habitat contiguity 0.2 0.2 0.2
Invasive vegetation 0.8 0.8 0.8
Hydrologic regime 1.0 1.0 1.0
Flood-prone area 1.0 1.0 0.7
Topographic complexity 0.6 0.2 0.6
Biogeochemical processes 0.8 0.8 0.8
TABLE 3
FUNCTIONAL ANALYSIS RATINGS FOR AQUA HEDIONDA CREEK
Rating:
Function Evaluation Criteria Agua Hedionda Creek
Rating:
Adjacent Non-wetiand Waters
Structural diversity
Spatial diversity
Habitat contiguity
Invasive vegetation
Hydrologic regime
Flood-prone area
Topographic complexity
Biogeochemical processes
0.8
0.8
0.4
0.8
1.0
0.7
0.2
0.8
0.2
0.2
0.2
0.4
1.0
0.7
0.2
0.8
TABLE 4
FUNCTIONAL ANALYSIS RATINGS FOR JURISDICTIONAL WAT
PHASE II MASTER PLAN AREA
;RS IN
Function Evaluation Criteria
Rating:
Wetlands
Rating:
Adjacent Non-wetiand Waters
Structural diversity
Spatial diversity
Habitat contiguity
Invasive vegetation
Hydrologic regime
Flood-prone area
Topographic complexity
Biogeochemical processes
0.6
0.6
0.4
0.8
1.0
0.7
0.2
0.8
0.2
0.2
0.2
0.4
1.0
0.7
0.2
0.8
Calavera Creek has stands of sycamore and willow trees with some mule fat shrubs in the
understory or as monotypic stands in openings of the tree canopy (Photographs 1 and 2).
The herbaceous layer of the understory is not well developed due to the dense tree
canopy, the nanow habitat, and adjacent agricultural activities. Small wetiand areas on
tributaries to the creek lack a well developed tree layer and are comprised on mostiy
shrubs or herbaceous species (Photograph 3). Non-wetland waters draining into the creek
are either vegetated with upland shrubs, non-native grasses, or cross cultivated fields
(Photographs 4 and 5).
Agua Hedionda Creek has stands of riparian forest comprised of sycamores, oaks, and
willows at the proposed crossing of College Boulevard (Photograph 6). Mulej fat shrubs
are found scattered in the understory, but the herbaceous layer is not well developed. The
non-wetland waters that are tributary to this creek are vegetated with primarily non-native
grasses.
Littie Encina Creek has a well developed tree canopy of oaks and willow over portions of
the project site (Photograph 7). Mule fat shrubs can be found scattered in the understory,
but the dense tree canopy and the nanow creek restrict the development of a significant
herbaceous layer. Small wetiand patches adjacent to the creek consist of freshwater or
seasonal alkali marsh, which lack a tree and shrub layer but have a den^e cover of
herbaceous vegetation. The non-wetland waters tributary to the creek are mostly
vegetated with upland shrubs and non-native grasses.
Wetiand areas within the master plan area of the project are composed of primarily
riparian scrub vegetation. Shrubs such as mule fat dominate the habitat wii:h scattered
willow trees present in small numbers. The understory is poorly developed on most of the
drainage courses due to the nanow channels and dense vegetation cover.
2. Spatial Diversity
Spatial diversity ranks are dependent on the amount of native riparian vegetation cover
and on the number of different native riparian species contributing to this cjover. Areas
with relatively high cover of native riparian species comprised of at least three genera are
given the highest rank.
Spatial diversity ranks for the three major creeks are similar due to the presence of
riparian woodland or forest habitat. Native riparian species such as syc tmore, oak,
willow, and mule fat are present along portions of these creeks. Spatial diversjity ranks for
wetiands adjacent to these creeks is much lower due to a lack of species diversity. Non-
wetland waters in the project area are primarily vegetated with upland plant species and
therefore have low spatial diversity with respect to wetlands.
10
PHOTOGRAPH 1
Riparian Woodland Along Calavera Creek
[1
0
PHOTOGRAPH 2
Location on Calavera Creek Where the Intersection
Of Proposed College Boulevard and Cannon Road
Will impact the Creek
M:\jobs\3226b\graphics\photos 1 -2.ai 10/24/01
PHOTOGRAPH 3
Freshwater Marsh Wetland Adjacent to Calavera Creek
ICI
M:\jobs\3226b\graphics\photo3 .ai 10/24/01
PHOTOGRAPH 4
Non-wetland Drainage in Coastal Sage Scrub
El
0
PHOTOGRAPH 5
Non-wetland Waters Affected by Agricultural Activities
M:\jobs\3226b\graphics\photos4-5.ai 10/24/01
PHOTOGRAPH 6
Location on Aqua Hedionda Creek (Background)
Where Proposed College Boulevard will Impact the Creek
0
M:\jobs\3226b\graphics\photo6.ai 10/24/01
PHOTOGRAPH 7
Riparian Woodland Along Little Encina Creek
I0l
M:\jobs\3226b\graphics\photo7.ai 10/24/01
3. Contiguity
Habitat contiguity ranks are dependent on whether the drainage feature or wetland
connects to similar habitats upstream and downstream, and the land uses adjacent to the
drainage are undisturbed. High ranks go to drainage features that connect to similar
habitats both up- and downstream and are suiTounded by undisturbed upland habitats at
least 100 feet wide.
Both Agua Hedionda and Calavera Creeks have similar riparian habitats upstream of the
project area, but are isolated from direct habitat connections downstream by the Rancho
Carlsbad Mobile Home Park development. Both creek channels within the mobile home
park are surrounded by development and they are nanow and devoid of any native
riparian vegetation. Littie Encina Creek is isolated to the northeast by development in the
city of Oceanside and to the southwest by the Rancho Carlsbad Mobile Home Park.
4. Invasive Species
This habitat characteristic is ranked by the amount of vegetative cover contributed by
non-native invasive plant species. Areas with less than 5 percent cover of invasive species
is given the highest rank.
The three major creeks contain some invasive plant species, but due to the nanow
channels and dense native riparian vegetation these creeks have less than 10 percent cover
of non-native plants. Only the tributary drainage courses adjacent to Littie Encina Creek
have less than 10 percent cover of invasive species, the other two creeks have tributaries
that have been disturbed due to agriculture and therefore these contain higher cover
values for non-native species.
Drainage courses within the Master Plan area, in general, have low cover of invasive
species. The dense upland vegetation and isolated riparian areas along these drainage
courses are relatively undisturbed helping to resist the invasion of this area by non-native
species.
5. Other Biological Habitat Values
The wetland and non-wetland waters in the project area provide other biological values
such as wildlife corridors within the project area, as well as to areas adjacent to the
property off-site. The native riparian vegetation cover offers nesting opportunities for
birds and cover for other animals. Seasonal flows provide a water source for wildlife.
16
B. Floodplain Characteristics
Three floodplain characteristics are considered when evaluating the functions and values
of wetlands. These are hydrologic regime, characteristics of the flood-prone area, and
topographic complexity of the floodplain.
1. Hydrologic Regime
The source of the water supply to the wetland area determines the rank for hydrologic
regime. Natural streams, rivers, and creeks with natural sources of water rank the highest.
All of the major creeks and their non-wetiand tributaries in the project area are primarily
dependent on natural sources of water. Calavera Creek is the only drainage on the project
that has a dam. The dam is located upstream of the project area and forms Calavera Lake.
Some urban storm mnoff and dry season runoff are contributed to these drainages from
adjacent developed areas. Runoff from agricultural activities also contributes
supplemental water to some of these drainage courses. Small seasonal alkali and
freshwater marshes have high or perched groundwater levels that help support these
wetland types.
2. Characteristics of the Flood-prone Area
Two characteristics of the flood-prone area of a wetiand are considered in the
determination of rank for this criteria. These are channel confinement and overbank flow.
Natural channels with little or no evidence of incision or confinement that exhibit
overbank flows are given the highest rank.
The three major creeks in the project area are earthen channels that are mildly incised or
confined such that overbank flow is experienced mostiy after a 10-year or greater flood
event. Calavera and Agua Hedionda Creeks are confined due to development of the
floodplains by ranches, agricultural activities, and urban improvements (e.g., roads,
homes, commercial areas). Littie Encina Creek is confined due to natural topography. The
non-wetland waters have drainage courses that are confined by either topography or
disturbance (i.e., agriculture).
3. Topographic Complexity
This feature is ranked by the presence of certain topographical characteristics of the
floodplain. These characteristics include the presence of pits, ponds, hummocks, bars,
rills, and large boulders. Floodplains that contain most of these features are given the
highest ranks.
17
Topographic complexity of Calavera and Agua Hedionda Creeks in the project area is
low due to the disturbance of the adjacent floodplains by agricultural or development
activities which make the floodplain relatively flat and featureless. Littie Encina Creek
has a nanow floodplain due to topographic confinement, but has greater topographic
complexity because the floodplain has fewer disturbances. Water courses within the
master plan area also have confined floodplains that are relatively undisturbed.
C. Biogeochemical Processes
The relative amount of cover of vegetation and leaf litter, debris, or detritus determine the
degree of roughness and organic carbon available to support natural biogeochemical
processes (i.e., the break down of organic and inorganic material into nutrients).
Roughness created by vegetation dissipates energy and slows flows. Organic matter found
in leaf litter, debris, and detritus provides a source of nutrients both on the site and for
transport to sites downstream. Wetland sites that contain greater than 20 percent relative
cover of vegetation and greater than 60 percent relative cover of debris, leaf litter, or
detritus are given the highest rank for this function.
The wetlands and non-wetland waters within the project area all have substantial cover of
vegetation, but the litter layer varies between and within drainage courses. Overall, most
drainage courses on the site have ample vegetation and litter cover to support natural
biogeochemical processes.
18
Water Quality and Beneficial Uses
Jurisdictional wetiands and non-wetiand waters on the project site provide a significant
contribution to local or regional water quality in terms of groundwater recharge, nutrient
removal, flood flow reduction, and sediment stabilization. The functions not only help
maintain the water quality on-site, but also help maintain the water quality in downstream
receiving waters (e.g., Agua Hedionda Lagoon).
Calavera and Little Encina Creeks are likely to have similar beneficial uses to those
designated for Agua Hedionda Creek. These beneficial uses include municipal and
domestic water supply; agricultural supply; industrial service supply; contact and non-
contact water recreation use; warm freshwater habitat; and wildlife habitat. These
beneficial uses will not be significantly affected by the proposed project because the
creeks will largely be preserved as natural open space and measures incorporated into the
project will minimize post-project changes to water quality.
19
Wetland Functions of Habitat to Be
Restored/Created
The anticipated wetland functions of the created willow/scrub determine the achievement
of compensation for impacts. Wetland hydrology and hydric soils conditions at the
mitigation areas will be maintained in the long term by seasonal rainfall, groundwater,
and project design features that will shunt water from developed areas to the mitigation
sites. Functional wetlands will evolve over time that will provide water, quality benefits
to downstream receiving waters such as enhancement of groundwater recharge, wildlife
habitat, enhancement of the wildlife corridors along these creeks, and provide native
habitat for nature study.
A. Habitat Characteristics
The existing structural diversity of the proposed on-site mitigation areas are low and
comprised of mostly exotic species of annual grasses and herbs with a few scattered
shrubs (see Photograph 1). No riparian vegetation exists on the proposed on-site
mitigation areas. After implementation of the mitigation, the structural diversity of the
on-site mitigation areas would improve greatly as the native riparian species become
established. Exotic species would decrease significantly. The resultant habitat in the
mitigation area would then become contiguous with similar habitats adjacent to the
mitigation sites both upstream and downstream.
B. Floodplain Characteristics
The areas adjacent to the proposed on-site mitigation area are not prone to flood often due
to the confinement of the water to the channel in Calavera and Little Encina. Overbank
flows to the proposed mitigation area likely occur only during relatively large flood
events. After implementation of the on-site mitigation the frequency of overbank flows
reaching the mitigation areas will increase by allowing smaller flood events to cause
overbank flow to these sites. This will be accomplished by lowering the elevation of the
mitigation sites to at least the elevation of the existing channel bottom.
Water at the proposed on-site mitigation areas will be provided by natural sources (i.e.,
seasonal rainfall, groundwater). After project development and the establishment of
native riparian habitat at the mitigation sites urban runoff would also be expected to
contribute to the hydrology of these areas.
20
C. Biogeochemical Processes
The roughness and organic carbon sources on the proposed on-site mitigation area are
from exotic upland species. Once the riparian vegetation of the mitigation effort is
established on the mitigation sites, roughness and organic carbon sources would be
provided by native vegetation. Natural biogeochemical processes will be low at first, but
increase rapidly as vegetation and litter layers develop.
D. Evaluation of the Mitigation Areas
The wetiand functions and values of the mitigation sites will be monitored as the sites
develop during the five-year monitoring period. Interim goals, as well as, ultimate goals
for the development of wetiand functions will be evaluated according to the criteria
contained in Function-Based Performance Standards for Evaluation the Success of
Riparian and Depressional/Emergent Marsh Mitigation Sites prepared for the U.S. Army
Corps of Engineers (Stein 1999b). A full discussion of the criteria for evaluation of the
mitigation areas is contained in the habitat restoration plan for the project (RECON
2001).
21
References Cited
RECON
2001 Habitat Restoration and Monitoring Plan for the City of Carlsbad Bridge &
Thoroughfare District No. 4, the Calavera Hills Project, and the Detention
Basins Project in Carlsbad, Califomia. Prepared for Planning Systems. October.
Stein, E.
1999a Function-Based Method for Assigning Mitigation Ratios for Impacts to
Riparian Systems. Prepared for the U.S. Army Corps of Engineers Los Angeles
District - Regulatory Branch. December.
1999b Function Based Perfomiance Standards for Evaluating the Success of Riparian
and Depressional/Emergent Marsh Mitigation Sites. Prepared for the U.S. Army
Corps of Engineers Los Angeles District - Regulatory Branch. December.
22