HomeMy WebLinkAbout3184; CANNON ROAD WEST; ADDENDUM TO CONCEPTUAL MITIGATION PLAN; 1998-02-20Addendum to Conceptual Mitigation Plan
for Cannon Road Extension Project Reaches 1 and 2
Prepared by:
Tetra Tech, Inc.
591 Camino de la Reina, Suite 640
San Diego, California 92108
Preparedfor:
CITY OF CARLSBAD
Engineering Department
2075 Las Palmas Drive
Carlsbad, California 92009-1576
February 20, 1998
ii
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
TABLE OF CONTENTS
1.0 INTRODUCTION ........................................................1
1.1 PROJECT DESCRIPTION ..........................................2
1.1.1 Location of the Project .........................................2
1.1.2 Overall Project Summary .......................................2
1.1.3 Responsible Parties ............................................3
1.1.4 Jurisdictional Areas to be Directly Impacted by Habitat Type .........3
1.1.5 Types, Functions, and Values of the Jurisdictional Areas to be
Directly or Indirectly Impacted ..................................4
2.0 GOAL OF MITIGATION .................................................9
2.1 TYPE OF HABITAT TO BE CREATED/ENHANCED ., ..................9
2.2 FUNCTIONS AND VALUES OF HABITAT TO BE CREATED ........... 9
2.3 TIME LAPSE .....................................................9
2.4 ESTIMATED COST ...............................................9
2.5 REQUIRED ACREAGE OF HABITAT TO BE CREATED ................ 9
3.0 FINAL SUCCESS CRITERIA ............................................11
3.1 TARGET FUNCTIONS AND VALUES ..............................12 . 3.2 TARGET HYDROLOGICAL REGIME ................................12
3.3 TARGET JURISDICTIONAL ACREAGE TO BE
CREATED/ENHANCED ............................................14
4.0 THE PROPOSED MITIGATION SITES .....................................15
4.1 LOCATION OF THE MITIGATION AREA ...........................15
4.2 OWNERSHIP STATUS ............................................15
4.3 EXISTING FUNCTIONS AND VALUES OF THE MITIGATION SITES ... 16
4.4 PRESENT AND PROPOSED USES OF THE MITIGATION SITES ........16
4.5 ZONING .......................................................16
5.0 IMPLEMENTATION PLAN .............................................19
5.1 RATIONALE FOR EXPECTING IMPLEMENTATION SUCCESS ........19
5.2 SCHEDULE .....................................................19
5.3 SITE PREPARATION ...............................................19
5.4 PLANTING PLAN ...............................................20
5.5 IRRIGATION PLAN ...............................................23
5.6 AS-BUILT CONDITIONS ...........................................23
5.7 REVEGETATION OF TEMPORARILY IMPACTED AREAS ............. 23
Cannon Road Extension Project i City of Carlsbad
Addendum to Conceptual Mitigation Planfor Reaches 1 and 2
TABLE OF CONTENTS (Cont'd)
6.0 MAINTENANCE DURING MONITORING PERIOD .........................25
6.1 REPLACEMENT OF DEAD OR DISEASED PLANT MATERIAL ........25
6.2 WEED CONTROL ...............................................25
6.3 PRUNING AND STAKING .........................................26
6.4 EROSION CONTROL .............................................26
6.5 SITE ACCESS .....................................................26
7.0 MONITORING PROGRAM ..............................................27
7.1 HORTICULTURAL MONITORING ..................................27
7.2 BOTANICAL MONITORING .......................................27
7.3 REPORTING ....................................................28
8.0 COMPLETION OF MITIGATION .........................................29
8.1 NOTIFICATION OF COMPLETION ................................29
8.2 CORPS CONFIRMATION ..........................................29
9.0 CONTINGENCY MEASURES ...........................................30
9.1 INITIATING PROCEDURES ........................................30
9.2 ALTERNATIVE LOCATIONS FOR CONTINGENCY MITIGATION ......30 . 9.3 FUNDING MECHANISMS ........................................30
9.4 RESPONSIBLE PARTIES .........................................30
10.0 REFERENCES ........................................................31
List of Figures
Figure 1 Location of Sites A-D ............................................. 17
Figure 2 Riparian Planting Design for 50'x 50' Cell .............................22
List of Tables
Table 3-1 Project Success Standards and Measures to be Taken if the
Standard is Not Met ...............................................11
Table 3-2 Plant Species Recommended for Cannon Road-Reaches 1 and 2
Willow Scrub Revegetation Site at Macario Canyon, Carlsbad .............13
Table 3-3 Mitigation Sites In Relation to Groundwater Levels ......................14
Table 3-4 Acreage of Proposed Mitigation Sites .................................14
Cannon Road Extension Project ii City of Carlsbad
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
1.0 INTRODUCTION
This conceptual mitigation plan identifies additional measures to offset impacts to wetland and
riparian resources that would result from the construction of Cannon Road Reaches 1 and 2, in the
City of Carlsbad, in San Diego County, California. This plan is intended to serve as an addendum
to the Conceptual Wetlands Mitigation Plan for Reaches 1 and 2 of the Cannon Road Extension
Project dated January 1997 (Tetra Tech, 1997). The purpose of the addendum is to satisfy the
California Coastal Commission's requirements for additional mitigation area for the project
(California Coastal Commission, 1998a, b). Details of the proposed project and other approved
mitigation is included in the original document cited above.
The mitigation measures described herein are designed to fulfill the requirements of existing project S
permits including:
U.S. Army Corps of Engineers (ACOE) Section 404 Permit Number 97-20130-TCD
and 97-20131-TCD;
U.S. Fish and Wildlife Service (USFWS) Biological Opinion 1-6-97-F-51
(08 October 1997);
California Department of Fish and Game (CDFG) Streambed Alteration Agreement
S Notification Number 5-273-89 and Section 2081 Management Agreement Number
2081-1998-0-5; and
California Coastal Commission (CCC) Coastal Development Permit No. 6-97-11.
Affected waters and wetlands occur in and adjacent to an unnamed water course in Mácario Canyon
and Agua Hedionda Creek. These streams flow into the Agua Hedionda Lagoon within one-half
mile of the affected areas. The proposed mitigation sites are located in and adjacent to the Agua
Hedionda Preserve, currently owned by Kelly Land Company. The preserve is the subject of an
Irrevocable Offer of Dedication in fee title to the CDFG as a requirement of the Kelly Ranch project.
Impacts (direct permanent) to jurisdictional wetlands due to bridge construction would be mitigated
at a 3:1 ratio. This ratio is a requirement of the CCC. The ACOE, USFWS, and CDFG previously
agreed to a 1:1 mitigation ratio if the mitigation was accomplished prior to construction. However,
the bridge support structures within Macario Canyon and Agua Hedionda Creek require substantial
time to settle prior to subsequent construction of the road. As such, these support structures must
be constructed soon, and the impacts associated with the relatively small footprints of these
structures cannot be mitigated prior to construction. In addition, permanent impacts to open water
(0.14 acre), and shading impacts to brackish marsh (0.1 acre) and riparian vegetation (0.8 acre)
would be mitigated at a 1:1 ratio. In addition to direct permanent impacts, temporary impacts would
Cannon Road Extension Project City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
5 be mitigated through replacement of disturbed vegetation onsite. Therefore, the mitigation ratio has
been increased and three new mitigation sites around the Agua Hedionda Lagoon watershed have
been added. In addition, the original mitigation site in Macario Canyon detailed in the Conceptual
Wetlands Mitigation Plan for Reaches 1 and 2 of the Cannon Road Extension Project (Tetra Tech,
1997) has been expanded.
1.1 PROJECT DESCRIPTION
1.1.1 Location of the Project
Reach 1 of Cannon Road would be located south of Agua Hedionda Lagoon between Interstate (1)-5
on the west and the proposed route of Faraday Avenue east of Macario Canyon (see Figures 1 and
2 in the Conceptual Wetlands Mitigation Plan for Reaches 1 and 2 of the Cannon Road Extension
Project). Reach 2 of Cannon Road extends from Faraday Avenue to El Camino Real. From its
interchange with 1-5, existing Cannon Road runs east about 1,000 feet, ending at LEGO Drive.
1.1.2 Overall Project Summary
The proposed Reach 1 of Cannon Road would extend from LEGO Drive onto the mesa above. Agua
Hedionda Lagoon and traverse Macario Canyon near its confluence with the lagoon basin. Reach
1 of Cannon Road is proposed to cross Macario Canyon on a bridge and terminate on the eastern
S canyon rim. Reach 1 was the subject of an Environmental Impact Report (EIR) certified on June 27,
1989.
The proposed Reach 2 of Cannon Road begins on the eastern edge of Macario Canyon and travels
northeasterly to the intersection with El Camino Real. The project area is bounded by El Camino
Real to the north, College Avenue to the east, and Palomar Airport Road to the south. The proposed
intersection alignment is at the eastern end of the project site and would connect Cannon Road to
El Camino Real. This requires the construction of a bridge over Agua Hedionda Creek. Reach 2 of
Cannon Road was originally analyzed under the development proposal of the Kelly Ranch EIR.
Permits from the resource agencies were obtained for that project in the middle- to late-1980s and
have since expired or are in suspense. These permits are currently being finalized.
Portions of the Kelly Ranch project were constructed, including grading for the alignment of Cannon
Road Reach 2 easterly of the Macario Canyon bridge. The width of the proposed Cannon Road
Reach 2 was cleared, graded, and all improvements for drainages, including desiltation basins, were
completed. Within the Cannon Road right-of-way, a surcharge and a temporary berm'were placed
on top of the intended future road. The current proposed project would finish the intended grading
(which would include the removal of the surcharge and the berm), resulting in the ultimate
construction of the road. The Cannon Road Reach 2 project will generally be constructed according
to the original grading and design plans with two exceptions. A slight modification has been made
Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
in the radius of a horizontal curve pulling the road away from the lagoon and removing the need for
a superelevated road section, and the bridge has been widened 10 feet (5 feet on each side) from the
originally approved bridge.
This plan provides partial mitigation for impacts from the current Reach 1 and 2 project. This plan,
combined with the approved Conceptual Wetlands Mitigation Plan for Reaches 1 and 2 of the
Cannon Road Extension Project (Tetra Tech, 1997) comprise the total mitigation for direct
construction, temporary construction and indirect shading impacts. This plan does not reflect the
entire mitigation package that includes mitigation for indirect impacts.
The entire length of the proposed Cannon Road is within the City of Carlsbad. Cannon Road is
included in the Carlsbad General Plan Circulation Element as a four-lane major arterial. The site
is also in the portion of the California Coastal Zone in the Agua Hedionda Land Use Plan, adopted
in 1982 as part of the City of Carlsbad Local Coastal Program.
1.1.3 Responsible Parties
Applicant:
Address:
Contact:
Addendum to Conceptual
Mitigation Plan Preparer:
Address:
Contact:
Final Mitigation
City of Carlsbad
2075 Las Palmas Drive
Carlsbad, California 92009-1576
(760)431-1164
Ms. Sherri Howard, Associate Engineer
Tetra Tech, Inc.
591 Camino de la Reina, Suite 640
San Diego, California 92108
(619) 718-9676
Mr. Brian W. Arnold, Principal Biologist
Plan Preparer: O'Day Consultants
Address: 2320 Camino Vida Roble, Suite B
Carlsbad, California 92009
(619)931-7700
Contact: Mr. Patrick O'Day
1.1.4 Jurisdictional Areas to be Directly Impacted by Habitat Type
The following jurisdictional areas would be directly and permanently impacted by the Cannon Road
project:
Cannon Road Extension Project City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Southern willow scrub
Reach 1 1.0 acre (direct impact)
0.8 acre (shading impact)
Reach 2 046 acre (direct impact)
Brackish marsh
Reach 1 0.01 acre (direct impact)
0.10 acre (shading impact)
Disturbed riparian scrub
Reach 2 0.13 acre (direct impact)
Open water
Reach 2 0.14 acre (direct impact)
Total 2.64 acres
In addition, 0.68 acre of riparian vegetation would be subject to temporary disturbance.
1.1.5 Types, Functions, and Values of the Jurisdictional Areas to be Directly or Indirectly
Impacted
Types
The existing plant communities identified within .the project area include open water, brackish
marsh, disturbed riparian scrub, and southern willow scrub. The southern willow scrub onsite occurs
along Macario Canyon Creek and Agua Hedionda Creek. Common native species include arroyo
willow (Salix lasiolepis), black willow (Salix gooddingii), and mulefat (Baccharis salicfolia). This
habitat primarily occurs in loose, sandy, or fine gravely alluvium deposited near stream channels.
Brackish marsh occurs in areas which support both saltmarsh and freshwater plant species, and
therefore, often occurs at th&mouth of canyons near lagoons. Common native species within this
habitat include pickleweed (Salicornia virginica), brassbuttons (Cotula coronopfolia), sedge (Carex
sp.), rush (Juncus sp.), cattail (Typha sp.), and salt-grass (Distichlis spicata).
The disturbed riparian scrub onsite is dominated by mulefat, coastal isocoma (Isocoma veneta), and
coyote bush (Baccharispilularis). This habitat occurs within the study area in the large basin at the
western end of the project and at the eastern end of the project on the north side of the creek. The
disturbed riparian scrub habitat at the eastern end of the site is located within the right-of-way,
Cannon Road Extension Project City of Carlsbad, California
Addendum to conceptuzl Mitigation Plan for Reaches 1 and 2
0 between the creek and El Camino Real. This habitat is poorly developed and is dominated by
mulefat and coastal isocoma.
Open water and sandy wash occurs where Cannon Road would cross Agua Hedionda Creek. Open
water habitat does not have emergent vegetation, but may have plants that float on the surface or are
submerged.
Functions and Values
The primary function of the waters in the area is the transport of surface and groundwater flows from
the watershed to Agua Hedionda Lagoon. Associated functions and values are discussed in this
section with emphasis on the habitat functions that depend on these waters.
Functions and values of the existing southern willow scrub, brackish marsh, disturbed riparian scrub
and open water habitats include contributions to local water quality, wildlife habitat, recreational
uses, and public access. A qualitative assessment of functions and values is presented in this section.
Wetlands and riparian habitat provides nutrient removal and transformation functions. The affected
areas are located downstream of agricultural fields used for the production of peppers during 1997.
Inspection of an aerial photograph (Aerial Fotobank, 1995) and orthophoto mapping from 1988 (City
of Carlsbad, 1991) indicate that these fields have been cropped for at least the previous 9 years. The . application of fertilizers to these cropped areas likely results in the transportation of leached nutrients
into the stream. In addition, nutrients from natural and non-agricultural human sources are expected
to enter the affected stream and groundwater systems. While the relatively small extent of the
affected habitats may limit the quantity of nutrients removed or transformed, they are expected to
contribute to enhanced water quality and nutrient resources both within the sfream system and in
Agua Hedionda Lagoon.
The affected southern willow scrub and disturbed riparian scrub habitat modify flood flows by
increasing the roughness coefficient. This reduces flow velocity and may result in the spreading of
high flow waters and the increase of surface area where recharge can take place. Marsh vegetation
is less resistant to flows and probably has less effect on the velocity and distribution of flood flows.
Crosby, Mead, Benton & Associates (1990) conducted a Sedimentation Basin Analysis for Reach 1
of Macario Canyon. They estimated that approximately 1.93 tons of fine- and medium-textured sand
and 0.82 tons of silt are eroded each year from the shrub covered hills of Macario Canyon. They
suggest that most of this is transported through the canyon and deposited in the upper reaches of
Agua Hedionda Lagoon. They further suggest that construction of roadways and embankments at
the mouth of the lagoon have impeded the movement of sediment into the Pacific Ocean.
40 Cannon Road Extension Project
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City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Where the velocity of flowing water is reduced, sedimentation generally increases. Deposited
sediments are "banked" until resuspended and transported away from the site. The binding action
of the roots of southern willow scrub vegetation is expected to enhance sediment stabilization where
this habitat occurs. Marsh habitat also binds sediment with a substantial root system and may
increase sediment deposition during low to moderate flows. The transportation of sediments into
Agua Hedionda Lagoon is in part controlled by these riparian habitat functions. Sediments also
provide substrate for riparian and wetland vegetation along the unnamed stream.
The value ofthe affected habitat for moderation of stream transported sedimentation to Agua
Hedionda Lagoon is rated as low to moderate due to the small size of the affected area. The high
value of the lagoon habitat is the primary reason for including the moderate designation. The
relatively small amount of sediment that is deposited within the unnamed creek and its adjacent
floodplain is of high value in the context of the riparian community.
Both southern willow scrub and marsh vegetation shade water that flows through them and may
moderate or reduce water temperatures. Water temperature is an important habitat characteristic for
aquatic fauna. Faber, et. al (1989) indicates that water temperature affects numerous stream
functions including processing of organic matter, chemical reactions and concentrations, metabolic
rates of stream invertebrates, and cues for life-cycle events. Shading may prevent summer water
temperatures from reaching lethal levels for fish and invertebrates. Stream shading by the affected
habitats is therefore expected to enhance habitat characteristics for both in-stream and benthic fauna.
The value of stream shading provided by the affected habitat is considered high. for the reaches of
Macario Canyon and Agua Hedionda Creek between the project area and Agua Hedionda Lagoon.
The large volume of water in Agua Hedionda Lagoon is likely to greatly dilute the thermal
contribution of this stream and, in this context, stream shading is expected to have a low value.
Habitat
The affected waters and wetlands also provide habitat functions and values for wildlife. Potentially
affected wildlife includes two species listed as endangered by the USFWS.
Least Bell's vireo (Vireo belli pusillus), occurs in the affected southern willow scrub habitat within
Reach 1 and 2. This species is dependent on riparian forest, woodland, and scrub habitats in
southern California. Two male willow flycatchers (Empidonax traillii ssp.) were observed in
southern willow scrub habitat adjacent to Reach 1 in Spring; 1996 and 1997. These birds were not
observed during subsequent surveys conducted late in each of the breeding seasons, and were
probably migrants moving through the area. Southwest willow flycatchers (Empidonax rraillii
extimus) may occasionally use the affected southern willow scrub habitat. No other species listed
as threatened or endangered by the USFWS are known to occur in the affected reaches.
40 Cannon Road Extension Project
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City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Southwestern willow flycatchers have not been observed in the affected reach of Agua Hedionda
Creek.
Other bird species observed during spring surveys conducted in Macario Canyon and Agua
Hedionda Creek include snowy egret (Egretta thula), great blue heron (Ardea herodias), Nuttall's
woodpecker (Picoides nuttallii), common yellowthroat (Geothlypos trichas), black-headed grosbeak
(Pheucticus melanocephalus), brown-headed cowbird (Molothrus ater), and others. Mammals
detected in the study area include coyote (Canis latrans), California ground squirrel (Spermóphilus
beecheyi), and common raccoon (Procyon lotor). Several small mammal species also occur in these
areas, including deer mouse (Peromyscus maniculatus), northwestern San Diego pocket mouse
(Chaetodipusfallaxfallax), San Diego desert woodrat (Neotoma lepida intermedia), and,dusky-
footed woodrat (Neotomafuscipes).
Aquatic species known to use these habitats include the mosquito fish (Gambusia affinis). Several
amphibians including the Pacific tree frog (Pseudacris regilla), and numerous invertebrates occur
in the affected waters and wetlands.
Due to the presence of least Bell's vireo, the affected habitat is considered to have high value. In
addition, the relatively high number of species observed during field surveys indicates the affected
habitat is a factor in maintaining local species diversity. This also contributes to the rating of high
habitat value.
Currently, the riparian area in Macario Canyon and Agua Hedionda Creek are used as habitation by
transients and agricultural workers. Human habitation of the affected area probably reduces the
ability of the canyon's riparian zone and wetlands to provide habitat for wildlife. Therefore, the
affected area's full value as wildlife habitat is not expressed.
These hydrologic and biologic functions occur in the regional context of coastal southern California
and within the watershed of Agua Hedionda Lagoon. The waters and wetlands of the project area
condition water flows, sediment movement, and nutrients; and affect the quality of water that
eventually enters the lagoon. The waters, habitats, and wildlife of Agua Hedionda Lagoon represent
regionally important resources. While the total affected acreage (3.01 acres)is relatively small
compared to the Watershed of the lagoon, these functions contribute proportionately to the lagoon
ecosystem.
Recreational Use/Public Access
The affected waters and wetlands provide the public with limited recreational opportunities. Birding
and walking activities probably occur, butdata are not available to evaluate the level of use. Off-
road vehicle use was frequently observed within the Macario Canyon study area. The presence of
human habitation may reduce public access and recreational opportunities.
0 Cannon Road Extension Project City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
No hunting, fishing, or other consumptive uses are known to occur within the affected waters and
wetlands. A moderate value level is assigned to the recreational uses/public access functions of the
site.
Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
2.0 GOAL OF MITIGATION
This section addresses the type of habitat to be created and/or enhanced, functions and values of
these habitats, estimated time lapse, and estimated cost. Since this mitigation plan is written at the
conceptual level, time lapse and estimated cost components of the analysis are treated at a general
level.
2.1 TYPE OF HABITAT TO BE CREATED/ENHANCED
The mitigation effort would result in the offsite creation of southern willow scrub habitat suitable
for least Bell's vireo. In addition, a small amount of brackish marsh vegetation will be created
offsite, and a linear area entirely contained within southern willow scrub vegetation will contain
seasonal flows which would represent an area of open water. In addition, southern willow scrub and
brackish marsh vegetation subject to temporary disturbance would be replaced onsite through
revegetation.
2.2 FUNCTIONS AND VALUES OF HABITAT TO BE CREATED
The functions and values associated with the created habitat are expected to be similar to those
described in Section 1.1.5.
23 TIME LAPSE
The mitigation effort described in this addendum would be implemented concurrent with or
subsequent to construction of the project. The desired time frame for establishment of the created
habitat is 1 to 3 years.
2.4 ESTIMATED COST
The City has estimated the cost of wetland creation at the sites including grading, installation,
irrigation, 5-year mitigation monitoring, and 5-year least Bell's vireo monitoring to be $114,420 per
acre.
2.5 REQUIRED ACREAGE OF HABITAT TO BE CREATED
The following mitigation acreage by habitat type is required by the CCC to mitigate the impacts of
the Cannon Road project on jurisdictional wetlands and waters of the U.S.:
Reach 1
U Southern willow scrub 1.0 acre (direct impact) @ 3:1 = 3.00 acres
0.8 acre (shading impact) @ 1:1 = 0.80 acre
Cannon Road Extension Project City of Carlsbad, California
Addendum to. Conceptual Mitigation Plan for Reaches 1 and 2
Brackish marsh 0.01 acre (direct impact) @ 3:1 = 0.03 acre
QJ.Q. acre (shading impact) @ 1:1 = Lifl acre
Sub-total Reach 1 1.91 acres 3.93 acres
(3.80 acres of southern willow scrub and 0.13 acre of brackish marsh)
Reach 2
Disturbed riparian scrub 0.13 acre (direct impact) @ 3:1 = 0.39 acre
Southern willow scrub ' 0.46 acre (direct impact) @ 3:1 = 1.38 acres
Open water ' 0.14 acre (direct impact) 1:1 = 0U4 acre
Sub-total Reach 2, 0.73 acre 1.91 acres
(1.77 acres of southern willow scrub and 0.14 acre of open water)
Total 2.64 acres of impacts mitigated by 5.84 acres of wetlands' creation
(5.57 acres of southern willow scrub, 0.13 acre of brackish marsh and 0.14 acre of
open water)
In addition, the 0.68 acre of riparian vegetation subject to temporary disturbance would be replaced
in kind through revegetation of the temporarily disturbed areas.
I
Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
3.0 FINAL SUCCESS CRITERIA
The final success criteria are presented in Table 3-1. The revegetation plan was developed as
mitigation to replace habitats lost during construction with comparable habitat or habitat with
increased functions and values. The USFWS has indicated that meeting the criteria presented in
Table 3-1 or detecting occupance of the southern willow scrub habitat by least Bell's vireo will
satisfy their concerns for project mitigation (U.S. Fish and Wildlife Service, 1997).
Table 3-1
Project Success Standards and Measures to be
Taken if the Standard is Not Met
Standard Measure if Standard Not Met
70% groundcover (visual estimate) based on hydroseed Reseed/replant
development
Establishment of all species planted
80% healthy container tree plantings
80% survival of tree plantings'
80% survival of shrub plantings'
Height standards met for all trees
Tree Heinht Standards2
Reseed/replant; substitutions possible
Replace with same species/size
Replant
Replant
Replant or receive remedial measures;
substitutions possible
Fremont Cottonwood 10 feet
Western Sycamore 9 feet
Willows 11 feet
Mulefat, Sandbar Willow, Mexican Elderberry 6 feet
Canopy cover standards met for trees and shrubs Replant or receive remedial measures,
substitutions possible
Canov Cover Standards'
Willow riparian woodland 80%
Brackish marsh 80%
Notes: 'At the discretion of the ACOE, dead container plants can be considered replaced by naturally invading seedlings.
2Mean height in feet.
'All canopy covers given in percentages.
`0 Cannon Road Extension Project
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City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 'l and 2
3.1 TARGET FUNCTIONS AND VALUES
It is anticipated that the functions and values of the proposed mitigation areas will be increased. The
proposed mitigation, along with the mitigation already approved for the project, will result in an
increase in habitat acreage and value in the general area. The proposed plant palettes provide
opportunities for a higher diversity of riparian trees and shrubs than currently occur in the affected
habitats.
Southern willow scrub is an early successional phase of more complex riparian woodlands and
forests (Holland, 1986). This vegetation type generally becomes established after severe scouring
events create the open, moist, mineral-based substrate typically required for willow germination
(Faber et. al, 1989). During its first 15 to 20 years of growth, it may have a lower species diversity
than more successionally advanced riparian woodlands. The plant palette for this target vegetation
includes tree, shrub, and understory species that are anticipated to provide resources not available
in the affected wetlands (Table 3-2). The inclusion of taller growing trees is expected to produce
habitat with enhanced structural diversity. As succession proceeds, this habitat is expected to
become southern cottonwood willow riparian forest.
3.2 TARGET HYDROLOGICAL REGIME
The target hydrological regime is similar to that present on the affected areas. The majority of the . hydrological functions are generated at the scale of the streams' watershed rather than within the
proposed mitigation area. The source of water will remain seasonal runoff and groundwater
discharge. Seasonal flooding will occur at similar rates and periodicities. The flow direction will
remain substantially the same and the size of the watershed is not expected to change significantly.
Water quality and sediment transport functions are also expected to be similar to the affected
habitats.
An additional hydrologic function that can be influenced by project design is the depth to
groundwater (DTG). The ACOE (1990) has indicated that the optimal DTG for willows and
cottonwoods is thought not to exceed 6 feet. Mulefat grows where DTG is between 0 and 10 feet.
The preferred DTG or depth of inundation for the dominant plant species will be an important factor
in determining the final elevation of grading in the target habitats. The willow riparian scrub habitat
should have a depth of no greater than 6 feet and should slope gradually upward toward the edge.
This will provide the variety of inundation depths required for the recommended palette species.
Cannon Road Extension Project City of Carlsbad, California
2
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2 . . Table 3-2
Plant Species Recommended for Cannon Road-Reaches 1 and 2
Willow Scrub Revegetation Site at Macario Canyon, Carlsbad
No. Per Acre or
Scientific Name Common Name Container Size Pounds Per Acre
Willow Riparian Woodland
Overstory Container Plants
Salix gooddingii Black Willow 1 gal 250
Salix lasiolepis Arroyo Willow I gal 250
Populusfremontii Fremont Cottonwood 1 gal 16
Platanus racemosa Western Sycamore 5 gal 16
Baccharis sa1icfo1ia Mulefat I gal 335.
Salix exigua Sandbar Willow I gal 335
Subtotal Plants/Acre . 1,202
Understory Container Plants .
Rosa ca1fornica Wild Rose 1 gal 30
Sambucus mexicana Mexican Elderberry I gal 50
Vitis girdiana Wild Grape 1 gal 10
Rubus ursinus California Blackberry I gal 30
Ribes indecorum Winter Current 1 gal 30
Subtotal Plants/Acre 150
TOTAL PLANTS/ACRE 1,352
Undertory Hvdroseed
Anemopsis ca1fornica Yerba Mansa 2 lbs*
Artemisia douglasiana Mugwort 2 lbs
Artemisia dracunéulus Tarragon . 2 lbs
Cotula coronopfo1ia Brass Buttons 1 lbs
Melilotus officinalis Yellow Sweet Clover 4 lbs
Pluchea odorata March Fleabane 2 lbs
Solidago caIfornica California Goldenrod 2 lbs
Festuca megalura . Foxtail fescue 3 lbs
Notes: *Pounds per acre should be confirmed with the native seed nursery. Pounds may vary based on viability of that particular
crop.
Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Table 3-3
Mitigation Sites In Relation to Groundwater Levels
Site
Number
Current Elevation
(Feet above Mean Sea Level)
Excavation
Required
A Described in Original Plan Yes
B 30-40 Yes
C 28-36 Yes
D 14-18 Yes
3.3 TARGET JURISDICTIONAL ACREAGE TO BE CREATED/ENHANCED
The mitigation proposed in this addendum includes four sites totaling 3.03 acres. The acreage for
each site is shown in Table 3-4. With the original 3.31 acres (at Site A) in the Conceptual Wetlands
Mitigation Plan for Reaches 1 and 20f the Cannon Road Extension Project (Tetra Tech, 1997), the
total mitigation acreage proposed is 6.34 acres, consisting of 6.07 acres of southern willow scrub,
0.13 acre of brackish marsh, and 0.14 acre of open water. This exceeds the total mitigation acreage
required by the California Coastal Commission of 5.84 acres, consisting of 5.57 acres of southern
5 willow scrub, 0.13 acre of brackish marsh, and 0.14 acre of open water by 0.5 acre.
Table 3-4
Acreage of Proposed Mitigation Sites
Site Number • Number of Acres
A (extension only) 0.79 (extension only)
B 0.44
C 1.30
D 0.50
Cannon Road Extension Project City of Carlsbad, California
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S
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
0 4.0 THE PROPOSED MITIGATION SITES
4.1 LOCATION OF THE MITIGATION AREA
The four proposed mitigation sites are within or adjacent to the Agua Hedionda Open Space
Dedication Area (Figure 1). The sites were chosen because they involve upland suitable for
conversion to wetlands, they are close to the impacted area, will be protected within the Agua
Hedionda Preserve, are currently disturbed and provide little habitat value, require, relatively little
grading, and have surface contours that can be modified to take advantage of existing groundwater
and surface water hydrology. Water flows.to and from the sites are the result of local runoff,
agricultural tailwaters, and possibly urban runoff from streets and developed areas within the
watershed. These flows are not currently controlled.
Site A is an extension of the originally proposed mitigation site in Macario Canyon as described in
Conceptual Wetlands Mitigation Plan for Reaches 1 and 2 of the Cannon Road Extension Project
(Tetra Tech, 1997). This site has recently been in agricultural production. The revegetation
treatment will be identical to that described in the above referenced plan (Tetra Tech, 1997).
Site B is located at the existing dirt road (Hidden Valley Road) adjacent to El Camino Real near
Agua Hedionda Creek. Southern willow scrub vegetation is located to the west and northwest
(Planning Systems, 1997), and a revegetation area is located to the east. The site is currently fill and
consists of the existing dirt road.
Site C is located west of and across Agua Hedionda Creek from Site B, and is surrounded by
disturbed mulefat scrub, freshwater marsh, upper saltmarsh, southern willow scrub, disturbed
southern willow scrub, and eucalyptus woodland. It is mapped as ruderal vegetation and eucalyptus
woodland, and supports eucalyptus trees that will be removed (Planning Systems, 1997).
Site D is located adjacent to Park Drive. It is bordered on the north by uplands, on the west by upper
salt marsh, and on the east and south by southern willow scrub. The existing habitat on Site D is
mapped as ruderal and disturbed lands (Planning Systems, 1997).
4.2 OWNERSHIP STATUS
Site A is on property currently owned by the City of Carlsbad and will be dedicated to the State of
California as open space. Site B is under ownership of Shea Homes and is the subject of a Coastal
Commission Open Space Restriction and a City of Carlsbad Open Space Easement. Site C and Site
D are currently owned by the Kelly Land Company, which has dedicated the land to the CDFG, to
be managed as part of the Agua Hedionda Lagoon Preserve. The CDFG has not yet accepted
responsibility for the land, pending identification of management endowment funds.
Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
0 4.3 EXISTING FUNCTIONS AND VALUES OF THE MITIGATION SITES
The proposed mitigation sites were selected from several candidate areas in the general Agua
Hedionda Lagoon vicinity. The proposed sites, when combined with the already approved
mitigation area, will provide the more than the required additional 2.06 acres of riparian mitigation
that is identified by the CCC in their Revisions to Staff Report and Preliminary Recommendation
dated 1/21/98 (CCC, 1998).
The existing functions associated with the proposed mitigation sites are minimal due to their
disturbed nature. The eucalyptus trees on Site C may provide raptor roosting perches. However,
there are other eucalyptus trees located closer to the lagoon which likely are used by roosting raptors.
The disturbed land may provide some habitat for small mammals and foraging area for raptors. The
value of these functions to wildlife is relatively low.
4.4 PRESENT AND PROPOSED USES OF THE MITIGATION SITES
The proposed use of the four mitigation sites is for wildlife and passive open space uses within Agua
Hedionda Lagoon and adjacent Preserve. The sites are surrounded by land that will be permanent
open space and which will provide a large diversified habitat area.
4.5 ZONING
S Lands on and adjacent to the proposed mitigation sites are zoned Open Space. The Carlsbad General
Plan designates these lands for Open Space.
0 Cannon Road Extension Project
16
City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Figure 1 - Location of Sites A-D (O'Day Consultants) 8.5 x 11
~ 0
Cannon Road Extension Project i City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Figure 1 BACK UP for double-sided copy
Location of Sites A-D (O'Day Consultants) 8.5 x 11
I
Cannon Road Extension Project
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City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
0 5.0 IMPLEMENTATION PLAN
5.1 RATIONALE FOR EXPECTING IMPLEMENTATION SUCCESS
The rationale for expecting successful implementation of the proposed mitigation include the City
of Carlsbad's strong commitment to this effort and the favorable physical conditions on the sites.
The City's commitment will lead to the selection of an implementation team with experience in
riparian and wetland mitigation. O'Day Consultants will use this Addendum to the Conceptual
Mitigation Plan as the basis for the final plan. The final plan will include:
Field survey to-tie in mitigation areas and property lines;
I Preparation of legal, plat, and closure documentation;
Erthwork calculation;
Detailed grading plan;
Erosion control plan;
Final grading cost estimate; and
Specifications for the work to be completed.
It is recommended that the final mitigation plan include measures to study the hydrology and
thoroughly test the salinity of soils in:the mitigation area; and if necessary, reduce soil salinity in
areas that would be planted to southern willow scrub. This may be accomplished with a soil . amendment such as gypsum. Gypsum replaces sodium ions with calcium allowing the sodium to
be leached out of the upper soil. An additional measure may include revegetating areas with marsh
vegetation on soils with higher ECES, particularly where these occur at the lower elevations of the
mitigation site.
5.2 SCHEDULE
The schedule for timing of site preparation and planting will be provided as part of the final
mitigation plan. The optimal time for installation of the plant materials is fall or early winter.
However, with irrigation, the area may be planted during the fall, winter, or spring.
5.3 SITE PREPARATION
The grading or landscape contractor will be responsible for all site preparation. The details of site
preparation will be prepared by O'Day Consultants and will be included in the final plan. A
biological monitor will be onsite (as needed) during final site preparation to verify correct placement
of plant materials and make minor adjustments to the final landscape plan, if warranted, based on
the final grading and hydrology plan.
Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Optimally, site preparation should begin in mid-September or as soon as the least Bell's vireo is not
present. This allows the project to take advantage of any rainfall during the winter and spring
months. Planting during this season also allows the plants to become established prior to heavy
rainfall and possible flooding. All trash will be removed from the mitigation sites prior to weeding
and subsequent planting and seeding. If available hydrology information indicates that the chosen
sites are likely to be flooded, the final plan will include measures designed to moderate the velocity
of water crossing the revegetation area. If such measures are not feasible, the possibility exists that
replanting after a flood may be necessary.
The success of revegetation efforts can be enhanced by providing an inoculum of mychorizal fungi.
This may be accomplished by obtaining leaf litter-and surface soils from existing riparian habitat
with similar soil chemistry. It is recommended that inoculum be obtained from the affected waters
and wetlands and/or riparian habitat adjacent to the revegetation area. Inoculum should only be
taken from areas free of invasive weed species.
5.4 PLANTING PLAN
The proposed revegetation sites are upstream of Agua Hedionda Lagoon. Tree species to be used
include: black willow, arroyo willow, Fremont cottonwood (Populus fremontii), and western
sycamore (Platanus racemosa). Shrub species include: mulefat, sandbar willow (Salix hindsiana),
wild rose (Rosa calfornica), California blackberry (Rubus ursinus), winter current (Ribes . indecorum), Mexican elderberry (Sambucus mexicana), and wild grape (Vitis.girdiana). Additional
species that would be seeded onto the sites include yerba mansa (Anemopsis calfornica), mugwort
(Artemisia douglasiana), tarragon (Artemisia dracunculus), brass buttons (Cotula coronopfolia),
yellow sweet clover (Melilotus officinalis), marsh fleabane (Pluchea odorata), California goldenrod
(Solidago calfornica), and foxtail fescue (Festuca megalura).
Plant Palettes
The plant palette to be used in the revegetation of southern willow scrub, will consist of a
combination of container plants and seed. Table 3-2 provides recommended plants and seeds. The
availability of these species should be confirmed with a native plant nursery and seed supplier prior
to completion of the final landscape drawings. If required, changes in the plant palette will be
reviewed by the monitoring biologist. Changes to the plant palette will be consistent with the overall
intent of the mitigation design and must include species native to southern California riparian
systems.
Plant material will be purchased from reputable nurseries specializing in native species. In addition,
the seed stock will be purchased from a company which continuously collects seeds of appropriate
species in southern California. If the nurseries or seed companies do not have stock on hand, onsite
collection may occur in the affected habitat. In addition, treatment of edge areas (described below) 1] Cannon Road Extension Project City of Carlsbad, California
• 20
Addendum to Conceptual Mitigation Plan for Reaches I and 2 . will require gathering of plant material from similar ecotonal locations within the Agua Hedionda
watershed, preferably within areas subject to disturbance (if applicable). These species can be stored
or grown in the nursery until ready to plant.
The final planting layout should cluster tree species and allow for some clusters of shrubs to provide
structural diversity, as shown schematically in Figure 2.
Planting Specifications
All sites will require excavation to provide correct hydrologic functioning. Southern willow scrub
will be planted where the DIG does not exceed 6 feet. Areas where the target vegetation is southern
willow scrub should be planted after, October 1 to reduce hot weather stress and to allow
establishment to occur during the cool, wet portion of the year. All areas will be planted with
container specimens and seeded with the appropriate hydroseed mix. Planting densities would be
high to allow rapid attainment of the cover goals. Densities may be increased by planting cuttings
in addition to the specified container stock. However, due to potentially high mortality, the cuttings
should not be included in survival counts. Approximately 25% of the planted container stock would
be at or above the height goal to enhance the probability that this goal would be quickly met.
Container plants will be planted prior to the application of the hydroseed. Hydroseed should be
applied mechanically with a slurry. A hydroseed company experienced with native seed applications
should be retained to complete this task.
Container trees and shrubs will be planted using standard horticultural practices: excavating a
planting hole twice the diameter of the root ball, filling the hole twice with water, and leaving the
plant crown approximately 1 inch above grade after planting. Plants will be placed in soils that have
been thoroughly watered before planting, and watered immediately after planting. Any roots
wrapped around the rootball will be loosened. The plants should be planted in clusters of three to
five simulating natural patterns.
The monitoring biologist will be present onsite during the planting and seeding procedures on an as-
needed basis. The monitoring biologist should conduct a final check of the site after the planting
is complete. The final check will document that plants were appropriately placed by the contractor,
hydroseed slurry has been correctly applied, and the correct species have been used.
Treatment of Edges
Ecotonal or edge areas, defined as the transition area between two distinct vegetation types, should
receive special planting treatments. For the edge areas between southern willow scrub and fresh
water marsh, mulefat and cattails should be planted in alternating groupings. These plants should
include 1-gallon nursery stock (if available), and should also include mulefat cuttings and cattail
plugs obtained from similar ecotonal areas subject to disturbance (if available), or from similar
Cannon Road Extension Project City of Carlsbad, California
21
. •l
I.
AM Overstory Container Plants
Salix goodingii Black Willow
Salix lasiolepis Arroyo Willow
Populusfremontii Fremont Cottonwood
Platanus racemosa Western Sycamore
Baccharis salicifolia Mulefat
Salix exigua Sandbar Willow
50 Feet
B Understory Container Plants
Rosa ca1fornica Wild Rose
Sambucus mexicana Mexican Elderberry
Vitis girdiana Wild Grape
Rubus ursinus California Blackberry
Ribes indecorum Winter Current
C M Understory hydroseed
Anemopsis californica Yerba mansa
Artemisia douglasiana Mugwrt
Artemisia dracunculus Tarragon
Cotula coronopfo1ia Brass Buttons
Meliotus officinalis Yellow Sweet Clover
Pluçhea odorata March Fleabane
Soli dago ca1fornica California Goldenrod
Festuca megalura Foxtail fescue
. S
Riparian Planting Design for 50'x 50' Cell
TETRA TECH INC. Figure 2
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
ecotonal areas within Agua Hedionda Lagoon. In addition, the standard riparian hydroseed mix
could be supplemented in these edge areas with cattail, brassbutton, sedge, and rush seeds.
For the edge areas between southern willow scrub and upper salt marsh, willow cuttings should be
planted in alternating groupings. The cuttings should include sandbar willow, arroyo willow, and
black willow, and should be a minimum of 18 inches and maximum of 36 inches in length. These
cuttings should be obtained from similar ecotonal areas subject to disturbance (if available), or from
similar ecotonal areas within Agua Hedionda Lagoon. Gathering the cuttings from willow trees
occurring adjacent to upper salt marsh, and thusadapted to more saline conditions, will increase their
survival in these upper salt marsh edge areas. In addition, the standard riparian hydroseed mix could
be supplemented in these edge areas with pickleweed, brassbutton, and rush seeds.
For the edge areas between southern willow scrub and uplands, wild rose, California blackberry,
winter current, Mexican elderberry, and wild grape should be planted in alternating groupings.
These plants should consist of 1-gallon nursery stock. The blackberry and rose could be used to
form a natural buffer to minimize human intrusion into the area.
5.5 IRRIGATION PLAN
Temporary irrigation will be supplied for the sites. The most feasible source of water is from
existing nearby agricultural operations. It is anticipated that irrigation will be buried PVC pipe with
40 overhead sprinkler heads. Although the use of irrigation will be temporary, it will be permanently
installed to reduce vandalism. Final irrigation design will be conducted by a landscape architect and
reviewed by the monitoring biologist.
5.6 AS-BUILT CONDITIONS
The City of Carlsbad will submit a report to the ACOE within 6 weeks of site preparation and
planting describing the as-built status of the mitigation project. Separate reports will be submitted
for grading, planting work, and erosion control measures, if completed within 6 weeks of each other.
The City will also provide the concerned agencies topographic maps showing as-built contours of
the mitigation area. These maps will indicate the location of plantings and any other installations
or structures.
5.7 REVEGETATION OF TEMPORARILY IMPACTED AREAS
In-kind revegetation/mitigation at a replacement ratio of 1:1 for all temporary construction impacts
to brackish marsh and riparian vegetation resulting from construction of haul roads, stockpile and
staging areas, and work areas will occur by revegetating and restoring the temporary impact area to
the original condition before disturbance. This revegetation will include remedial work such as
S Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
decompaction and surface treatment (such as ripping, if needed). Revegetation techniques, including
hydroseeding, plant palettes, numbers and groupings, will follow those described in the Conceptual
Wetlands Mitigation Plan for Reaches 1 and 2 of the Cannon Road. Extension Project (Tetra Tech,
1997) and above, depending upon the vegetation type temporarily disturbed. Also, all disturbed or
manufactured steep slope areas, including the fill structure on the east side of Macario Canyon, will
be hydroseeded with a coastal sage scrub mix (identical to that previously used for the initial berm
along the graded, unpaved Cannon Road). The resultant native vegetation will be compatable with
adjacent natural vegetation and will re-establish the area consistent with its present character.
S
Cannon Road Extension Project - City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
6.0 MAINTENANCE DURING MONITORING PERIOD
The revegetated areas will require regular maintenance including inspection of the sites for erosion
problems, weed invasion, irrigation adequacy, herbivory, unhealthy or dying plants, removal of trash
and actions necessary to prevent off-road vehicle use and illegal dumping. These maintenance
activities will be implemented throughout the monitoring period.
6.1 REPLACEMENT OF DEAD OR DISEASED PLANT MATERIAL
All container plant materials will be inspected by the biological monitor 90 days after planting. At
that time, dead plants will be replaced in-kind by the contractor. If disease. or insect damage is
detected, an assessment of the causal agents will be made and appropriate action will be taken. All
replacement plantings will be made in late fall or winter. Thereafter, plantings will be assessed
monthly during the monitoring period. Dead plants will be replaced by the City of Carlsbad.
Disease and insect damage will also be assessed and appropriate actions taken as necessary for the
full monitoring period. .
Seeded areas will be assessed 120 days after seeding and monthly thereafter for a 1-year monitoring
period or until performance standards are met. Seeded areas determined by the biological monitor
not to have obtained 50 percent coverage or better are to be reseeded at the expense of the, contractor
at 120 days, and thereafter if necessary, at the expense of the City of Carlsbad.
6.2 WEED CONTROL
Weeding prior to seeding is important since non-native species will compete with the native
seedlings. An aggressive weed eradication program will be implemented prior to site preparation,
planting and seeding, and continue over the maintenance and monitoring period. Weed removal and
control methods include:
. Removal of specific weedy species, including but not limited to, pampas grass
(Cortaderia jubata), tree tobacco (Nicotiana glauca), and Brazilian pepper tree
(Schinus terebinthifolius) through foliar application or cut-stump treatment with an
appropriate herbicide;
Hand removal of entire plant including the root system; and
I Girdling of larger trees or shrubs.
The specific method will be recommend by the monitoring biologist.
40 Cannon Road Extension Project I City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
Weed abatement techniques will vary depending on species. Small shrubs should be removed by
hand; however, the size of the plant will determine the feasibility of complete removal. If plants are
too large to dig out by the roots, they can be cut back at the base, then the cut base can be painted
with an appropriate herbicide as recommended by the biological monitor.
6.3 PRUNING AND STAKING
No pruning or leaf litter removal will take place within the mitigation site since the goal is to create
natural habitat functions. Therefore, dead branches will be left on the shrubs and trees and leaf litter
and fallen branches will not be cleared away from the planting. Pruning may be done only if
required for insect and/or disease control. Trees in 15-gallon or larger containers should be staked.
6.4 EROSION CONTROL
An erosion control stock will be included in the hydroseed mix. This species should be an annual,
fast growing species which does not readily re-seed. The native seed company will be able to
provide recommendations for such a crop. The correct species should provide erosion control during
the first year. This will allow the native seed to germinate and develop the following year. Native
vegetation will provide erosion control for the remainder of the monitoring period.
6.5 SITE ACCESS
Measures to prevent off-road vehicles ingress into the sites will be included in the final plan.
Maintenance crews and the biological monitor will be responsible for reporting vandalism and
trespassing to the City. Barrier plants such as blackberry and rose could be used to form a natural
buffer to reduce human intrusion into the area.
I Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
0 7.0 MONITORING PROGRAM
An important component of any revegetationlmitigation program is documentation of progress until
the specified monitoring period is completed and the mitigation is deemed successful by the
permitting agencies. General observations will be important in documenting areas of poor growth
or cover, dead or dying plants, weed invasion, erosion problems, and inadequate hydrology.
Documentation will be provided by the monitoring biologist.
The primary goal of the revegetation effort is to establish self-sustaining southern willow scrub
habitat. Monitoring will be accomplished by a qualified biologist with appropriate credentials and
experience.
The monitoring program will use a variety of qualitative and quantitative procedures to document
the changes in growth and density of the desired species within the sampled areas. One of the most
important procedures will be standardized observations of the sites to provide a general record of
trends within the mitigation sites. Quantitative studies will be conducted to obtain cover estimates,
densities, and monitor changes in species diversity. All changes in growth and survivorship will be
documented to determine the success of establishment over the monitoring period.
7.1 HORTICULTURAL MONITORING
The biological 'monitor will inspect the mitigation site monthly after the installation of the plant
materials. The responsible maintenance staff at the City of Carlsbad will participate in each site visit
to discuss any remediation or maintenance measures required. The entire site will be assessed
qualitatively for evidence of erosion, weed invasion, hydrological problems, vandalism, and plant
mortality. Notes on the general health and growth of the container plants and hydroseeded areas will
be made during these visits. The results of the horticultural monitoring will be included in the
annual report required by the resource agencies. If immediate attention is required, an interim letter
report will be sent to the City after each qualitative monitoring period.
7.2 BOTANICAL MONITORING
Quantitative data will be collected twice yearly during the monitoring period. Information gathered
will, include survivorship of container stock, species covet, species composition, tree height, percent
native versus non-native species, and species density of understory seeded areas.
Quantitative measurements may include, but not be limited to, permanent 1 meter x 1 meter
quadrants placed at random locations within the mitigation site. These locations will be sampled
each year. Quadrant sampling will be used to determine percent cover of the herb and seedling layer.
The herb and seedling layer will include all plants less than 0.5 meter in height. Twenty-five meter
line intercept transects will be used for collection of cover data for the tree and shrub layers. A 6-
Cannon Road Extension Project
,
City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
meter belt transect will be placed along each 25-meter transect to sample tree and shrub density.
Height measurements will be taken of each tree and shrub rooted within the 6-meter belt. Average
height of vegetation layers will also be estimated. Photographic documentation points will be
established at one end of each transect and photographs will be taken during each monitoring period.
The data will be analyzed and reported at the end of the monitoring year.
7.3 REPORTING
At the end of the year, the biological monitor will submit an annual report to the City of Carlsbad.
The report will include results of survival, percent cover, density, tree height and girth, germination
of seeded areas, and wildlife present. It will be the responsibility of the City of Carlsbad to submit
the reports to the appropriate resource agencies.
Annual reports will be submitted to the ACOE and other involved agencies. These reports will
assess growth and progress toward the final success criteria. Annual reports will include the
following information:
A list of names, titles, and companies of all persons who prepared the content of the
annual report and participated in monitoring activities for that year;
U A copy of the ACOE permit, any attached Special Conditions, and any subsequent
letters of modification, as an appendix;
Analysis of all quantitative monitoring data (success, failure, and remedial action).
Graph and table format is preferred;
Prints of all included monitoring photographs (colored photocopies are acceptable);
Maps identifying monitoring areas, transects, planting zones, etc., as appropriate; and
Copies of all field data sheets shall be available for ACOE review upon request (U.S.
Army Corps of Engineers, 1993).
Cannon Road Extension Project City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
8.0 COMPLETION OF MITIGATION
The mitigation effort will be completed when the City of Carlsbad notifies the ACOE and receives
written confirmation that the ACOE is in agreement.
8.1 NOTIFICATION OF COMPLETION
When the initial monitoring period is complete and if the City considers the final success criteria
have been met, the City will notify the ACOE of completion in the final annual report.
8.2 CORPS CONFIRMATION
The City understands that following the receipt of the final annual monitoring report, the ACOE may
require a site visit toconfirm the completion. :
Cannon Road Extension Project
•
City of Carlsbad, California
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
9.0 CONTINGENCY MEASURES
9.1 INITIATING PROCEDURES
If an annual performance criterion is not met for all or any portion of the mitigation project in any
year, or if the final success criteria are not met, the City will prepare an analysis of the cause or
causes and, if determined necessary by the ACOE, will propose remedial action for approval.
9.2 ALTERNATIVE LOCATIONS FOR CONTINGENCY MITIGATION
If mitigation efforts are not successful at the four sites, additional mitigation sites may have to be
identified and planted.
9.3 FUNDING MECHANISMS
The funds available for the implementation of contingency measures have not been determined to
date. This information will appear in the Final Mitigation Plan or will be provided to the ACOE
prior to beginning work on the mitigation effort.
9.4 RESPONSIBLE PARTIES
S The City of Carlsbad will have final responsibility for implementing, monitoring and contingency
efforts. The contractors who will be responsible to the City for these project components have not
been determined.
Cannon Road Extension Project City of Carlsbad, California
Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
10.0 REFERENCES
Aerial Fotobank, Inc.
1995 Aerial Photograph of the project area. Scale 1 inch = 200 feet. Negative Number
CVSD95-80xx. Flown February 2, 1995.
Bedish, J.W.
1967 Cattail Requirements and Their Significance to Marsh Management. American
Midland Naturalist. Vol. 78.
California Coastal Commission
1998a Regular Calendar Staff Report and Preliminary Recommendation, Application No.
6-97-11. 21 January.
1998b Revisions to Staff Report and Preliminary Recommendation dated 1/21/98. 2
February.
City of Carlsbad
1991 Map. Orthophoto Mapping. Scale, 1 inch = 100 feet. Flown September-October
1988. . Crosby, Mead, Benton and Associates
1990 Personal Communication. Letter from Mr. A.W. Urquhart, P.E. with Crosby Mead
Benton and Associates to Mr. Paul Webb, California Coastal Commission. 10 May.
Faber, P.A., E. Keller, A. Sands, and B.M. Massey
1989 The Ecology of Riparian Habitats of the Southern California Coastal Region: a
Community Profile. U.S. Fish and Wildlife Service Biology Report 85(7.27).
Holland, R.
1986 Preliminary Description of the Terrestrial Natural Communities of California.
California Department of Fish and Game. Sacramento, California.
Planning Systems
1997 Biological Inventory Map, Offer to Dedicate Area, Kelly Ranch, Carlsbad, California.
Poiani, K.A. and Johnson, C.W.
Effect of Hydroperiod on Seed Bank Composition in Semi-Permanent Prairie Wetlands.
Canadian Journal of Botany. Vol. 67.
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Addendum to Conceptual Mitigation Plan for Reaches 1 and 2
10.0 REFERENCES (Cont'd)
Tetra Tech, Inc.
1997 Conceptual Wetlands Mitigation Plan for Reaches 1 and 2 of the Cannon Road
Extension Project. January.
U.S. Army Corps of Engineers
1993 Habitat Mitigation and Monitoring Guidelines. Los Angles District. 01 June.
1990 Draft Review and Analysis of Drought Tolerance of Riparian and Estuarine Species.
Prepared by The Chambers Group. Los Angles District. October.
1987 Fulton: Las Coches Mitigation Area: A Case Study in Native Plant Revegetation Los
Angeles District. Proceedings of the Second Native Plant Revegetation Symposium.
U.S. Fish and Wildlife Service
1997 Biological Opinion. Letter from Gail Kobetich, U.S. Fish and Wildlife Service to Col.
Robert Davis, U.S. Army Corps of Engineers. 08 October.
Woodward-Clyde Consultants
1990 Report of John Moossazadeh, Woodward-Clyde Consultants to Mr. W. McCloskey.
The Buie Corporation. 02 July.
Cannon Road Extension Project City of Carlsbad, California