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HomeMy WebLinkAbout3466; OLIVEHAIN RD WIDENING AND REALIGNMENT; YEAR SIX FINAL LETTER REPORT; 2004-01-12I amen! 12 January 2004 City of Carlsbad ' Ms. Sherri Howard .: Associate Engineer 0 Public Works-Engineering 1635 FaradayAvenue Carlsbad, California 92008 Subject: Olivenhain Riparian Mitigation Site: Year 6 Final Letter Report Dear Ms. Howard: 0 " AMEC Earth & Environmental, Inc. (AMEC) submits this final letter report for the sixth year of biological monitoring of the Olivenhain Riparian Mitigation Site (mitigation site). The mitigation site is located in north San Diego County in Carlsbad, California (Figure 1). This project is permitted under California Department, of Fish and Game (CDFG) Section 1601 Streambed' Alteration Agreement No. 5-560-94 and U.S. Army Corps of Engineers (USACE) Section 404 Nationwide Permit No. 95-20096-13H. The permit requirements include the creation, planting, and 5-year maintenance and biological monitoring of 0.5 acre of wetland habitat (0.34 acre of southern willow scrub and 0.16 acre of freshwater marsh) and the replacement of 02-1 acre of southern willow scrub and 0.14 acre of freshwater marsh that were temporarily impacted during construction. The permit also addresses the 1.1-acre flood control dike located adjacent to the mitigation area. - - Background The mitigation site is required compensation for construction-related impacts to wetland habitat associated with the widening of Olivenhain Road in Carlsbad, California.' The City of Carlsbad (City) is responsible for the mitigation effort. AMEC has performed biological monitoring 0 services for this mitigation site since 1998. AMEC conducted a field visit on 23 July ?003 accompanied by Sherri Howard (City), Terry Dean (USACE), and Tamara.. Spear (CDFG) to discuss the progress of the mitigation site. Jessie Walker (AMEC) informed the USACE and CDFG that most of the mitigation site had existed under, natural conditions (i.e., without supplemental irrigation) since 2001 and that a smaller portion of the mitigation site had existed under natural conditions since December 2002. To date, the entire mitigation site has existed 0 under natural conditions for 1 year. During the July field visit, USACE informed-the City and ' 0 AMEC that a wetland delineation should be performed to determine the jurisdictional wetland acreage at the mitigation site. Only after the determination was completed and a letter report supplied to the regulatory agencies would mitigation site sign-off be considered. 325400000-3005/3151-1203R126.doc Page 1 £471QJ7r$ LA COSTA ,.. •. . . . . . A 4O A PROJECT &1TE R440,V £4A'TA if . . . N NflT TO Al F 111 Ms. Sherri Howard City of Carlsbad, Olivenhain Riparian Mitigation Site: Year 6 December 2003 amec Methodology 0 Horticultural Monitoring During the sixth year, horticultural monitoring consisted of three site 'visits conducted to determine site conditions and tomonitor the landscape contractor's maintenance activities: Plant mortality, vegetation development, weed establishment, and vandalism were assessed during each visit. AMEC made one horticultural monitoring visit in March, one in April, and one in December 2003. During the April and December, site visits, AMEC also assessed the two, areas that were temporarily impacted, one located along Olivenhain Road and the other on the southeastern corner of the intersection of 'Olivenhain Road and' El Camino 'Real. Based on ' observed site conditions, AMEC recommended maintenance measures to the landscape" contractor, Native Landscape, Inc. ' ' ' ' '• Botanical Monitorin Quantitative botanical monitoring consisted, of, collecting line intercept data from transèctslo. describe vegetation development, collecting tree heights, and counting dead container plants. Quantitative data were collected for the mitigation site for 5 years; however, no quantitative data• were collected during the sixth year since success criteria were achieved after the fifth 'year of ' mitigation. During the 5 previous yéars,'the line intercept method was used to quantitatively' evaluate the success ,of the mitigation site. Percent vegetative cover was obtained using this method. 'AMEC took line measurements on four transects located throughout the 0.5cre mitigation site to determine cover and spéciés composition '(Figure 2) in year 5. ' A ' representative sampling of trees and shrubs- existing in the mitigation area, including both ' container' and, volunteer plants, was measured for tree and shrub heights. Tree and shrub heights were collected using a tree height measurement instrument. ,The health of container plants was visually' assessed for container plants installed within the mitigation area. In addition, the number of dead container plants throughout the mitigation area was determined and. "- evaluated against the success standards. Photographs were also.taken at the beginning of each. •' transect. The quantitative data collected in year 5 is presented in this letter report for reference purposes. Refer to the Fifth Annual Report Olivenhain, Road Widening Wetland, Mitigation Area, January 2003, for a complete history and discussion of the mitigatiOn site, including mitigation site photographs. Wetland Delineation AMEC biologists Jessie Walker and Julie Simonsen-Marchant conducted a Clean Water Act' (CWA), Section 404, wetland delineation of the mitigation site on 5 December 2003. Three soil pits were excavated at vegetation community transition 'areas and examined for three' wetland indicators - hydrophytic vegetation, -wetland hydrology, and hydric soils —as discussed below. , The USACE regulates the discharge of fill material into waters of the U.S. Waters of the U.S. include wetlands and non-wetland water bodies meeting specific criteria. Waters of the U.S. are ' typically regulated as jurisdictional by the, USAC,E if the drainage exhibits at least intermittent " flow. Evidence of intermittent flow typically includes the formation' of bed and bank, debris 325400000-3005/3151-1203R126.doc Page 3 i* IIt! 's - Legend Project Locá5' f N Map Note 0 ,/\,' vegetation Transacts Coastal Salt Marsh/Freshwater Marsh SANDAG-2000 2-loot resolution, 3-band false color infra-red imagery AMEC Welland Mitigation Area, Transitional Habitat or, Dike Southern Willow Scrub 'r., . Transitionat Habitat, Vegetation Transacts Upland Transitional Riparian Habitat 0 25 50 75 100 Feet Olivenhain Road Wetland Mitigation Area F I G U R E ame 2003 2 OisOroliolivonhn/a,cwap/Iig_2.nsxd 1/11/04 Ms .Sherri Howard . . City of Carlsbad, Olivenhain Riparian Mitigation Site: Year 6 December 2003 amec* deposits and scoured channels USACE jurisdiction over waters of the U.S. extends to the ordinary high water mark (OHWM) of the feature As defined by USACE regulations waters of the U.S. include these traditional drainage features, as well as a range of other waters, including All interstate waters, including interstate wetlands; . . .• All other waters, including intrastate lakes rives streams mudflats sandflats wetlands sloughs prairie potholes, wet meadows playa lakes or natural ponds for whichthe use degradation or destruction of could affect interstate or foreign commerce All impoundments of waters that fit the description Tributaries to any defined waters Territorial seas; and . . .: •: Wetlands adjacent to waters The USACE defines wetlands as Those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support and that under normal circumstance do support, a prevalence or vegetation typically adapted to life in saturated soil conditions Therefore, under Section 404 of the CWA, an area is considered a jurisdictional. wetland. if it possesses all three of the following wetland attributes: .' . •; . ••• • . 1 Hydrophytic vegtation, Wetland hydrology, and . . . . •• . ..• . . Hydric soils. . • . . . .. . . . Areas are evaluated in the field for these wetland characteristics according.:to the methods defined in the 1987 Corps of Engineers Wetland Delineation Manual Hydrophytic vegetation is defined as plant species that grow and are adapted to the conditions of permanently or 1 • periodically saturated soils. The presence or absence-of hydrophytic vegetation-was determined by developing a list , of plant species preent within the area in question, determining the dominant of each species within each. strata (tree, shrub, and herb), and determining the • wetland status of each species Wetland plant indicator status was obtained from the U.S. Fish and Wildlife Service (USFWS) National List of Plant Species That Occur in Wetlands California (Reed 1988). If more than 50 percent of the dominant vegetation species were ôlassifiedas obligate facultative wet or facultative then hydrophytic vegetation was determined to be present Wetland hydrology was determined by several factors including the presence of water in the soil pit, presence of saturated soils, presence of ponded surface water, drift lines, sediment deposits and drainage patterns within a wetland Secondary hydrology indicators include oxidized root channels, water-stained leaves and local soils survey data No recorded flow data were available for the site, but aerial photos were used as an indication of wetland hydrology. . • 2 • 325400000 3005/3151 1203R126 doc Page 5 'Ms. Sherri Howard City of Carlsbad, 0iivenhain Riparian Mitigation Site: Year 6 December 2003 amec Hydric soils are flooded, ponded, or saturatëdfora period during the growing season sufficient to develop anaerobic conditions in the upper layers, favoring the growth of hydrophytic vegetation. Soils must meet at least one of the' following criteria to be considered hydric: 1. Classified as organic soils (Histosols, except the Folists), '2. Exhibits a histic epipedon, 3. Contains sulfidic materials, 4 Exhibits a moisture regime that is aquic or peraquic, Exhibits reducing, soil conditions, Exhibits the gleyed soil color or low matrix color, Listed on a hydric soils list. For sandy soils, hydric soils can sometimes be determined by the presence of high organic matter in the surface horizon or streaking of organic matter in the subsurfaàe layers. 41n many cases, soil 'color is the'most diagnostic field tool for determining the presence of hydric' soils Soil color was determined by4 digging a soil pit to a depth of 16 inches and determining the matrix, chroma and hue of the soil sample of each horizon with Munsell® Soil Color Charts (1975). If the soil was gleyed, had no mottles and a chroma of one or less, or if mottles were; present and the chroma was two or less, the soil was determined to be hydric. 'In cases where the soils were sand or recently deposited river sand, a problem area or natural atypical situation' occurs where it is not possible to determine soil color. In these cases, the 1987 Corps manual does not require soil pits, ,and jurisdictional 'wetlands are delineated based on other indicators of hydric soils, the indicators of hydrophytic vegetation and wetland hydrology, and professional judgment. Results Horticultural Monitorina Results There was no plant mortality in the mitigation area and all of the plants have been without ,supplementaI irrigation for 1 to 2 years.'Natural recruitment and native plant establishment were noted throughout the mitigation area.,Many willow (Salix ssp) saplings and seedlings are located througho,ut southern willow scrub portion of the mitigation site Many additional naturally recruiting species such as giant wild rye (Leymus condensatus), yerba mansa (Anemopsis caIifornica), coastal goldenbush (Isocoma rnenziesii),. tall cattail . (Typha latifolia), bulrush (Scirpus mantimus and S californicus) and alkali heath (Frankenia sauna) were observed in the mitigation site. Several new species including centaurium (Centajirium venustum) and grass poly (Lythrum hyssopifolium) were located this year for the first time. • , . ' . ' Several vegetation communities exhibiting several seral stages now exist within the mitigation site The primary vegetation communities include southern willow scrub, coastal salt marsh freshwater marsh, and upland riparian' scrub. Seral stages range. from early (southern willow scrub) to mid-successional (freshwater marsh and coastal salt marsh). Many avian an mammalian species have been observed foraging in the mitigation site including coyote (Canis -J 325400000-3005/3151-1203R126.doc Page 6 - Ms. Sherri Howard City of Carlsbad, Olivenhain Riparian Mitigation Site: Year 6 December 2003 S amec latrans), pacific treefrog (Hyla regilla),. lesser goldfinch (Carduelis psaltria), mourning dove' (Zenaida macroura), black phoebe (Sayornis nigricans), mice (Chaetodipus sp.), and bobcat (Fe/is rufus). .A white-tailed kite (Elanus leucurus majusculus), a sensitive avian species, has been observed perched on a snag in themitigation site many times over the past several years. Invasive plants including fennel (Foeniculum vulgare), Bermuda grass (Cynodon dactylon), tamarisk (Tamarix ssp.), black mustard (Brassica nigra), bristly ox-tongue (Picris echioides), and yellow sweet clover (Melilotus officinalis) were located in the mitigation site. These populations were controlled and/or eliminated during-two visits this past year by Native Landscape', Inc. the landscape maintenance contractor. Vandalism and trash were not problematic in the mitigation site during the past 5 years, but this. year ,people used the site for collecting cattails and other native plants for seed and the floriculture industry. As 'a result, the mitigation site vegetation has been cut and somewhat trampled from people walking on it during their collection visits. Botanical Monitorina Results (Year-5 Percent Cover . ' ' ' ' " •.. The percent cover standard for year 5 was achieved in 2002; therefore, no quantitative data were collected in 2003. . The total cover for all species by year .5 in the mitigation area was 135.8 percent (Table 1). Native species cover was' 135.5 percent and nonnative species cover - was 0.3 percent. The dominant native species was coastal goldenbush with a percent cover of 38.1.. Picklewéed (Salicornia virginica) 'was the second most dominant species at the mitigation area with a percent'cover of 17.6. Wetland indicator species such as willow species, bulrush, and tall cattail were not represented in the percent cover data; however, these species do occur in the mitigation area and were found in areas where the transects were not placed. Black mustard was the most dominant nonnative species with a percent cover of 0.2, whiOh is .extremely low. Table '1 OLIVENHAIN ROAD WETLAND MITIGATION AREA . - .. '. .. ... ' . PERCENT COVER (2002) Botanical Name ' 'Common Name ' Absolute Cover (%) Isocoma menziesii coastal goldenbush ' 38.1 Salicornia virginica * . pickleweed . ' 17.6 Artemisia pa/men * Palmer's sagewort ' 16.8 Distich/is spicata * saltgrass 10.9 Ambrosia psiostachya * S - western ragweed . 8.8. Leymus condensatus ' giant wild rye ' ' 7.4 'Frankenia sauna * alkali heath ., 6.6 5 325400000-3005/3151 -1203R126.doc Page 7 ) ki Ms. Sherri Howard City of Carlsbad, Olivenhain Riparian Mitigation Site' Year 6 ( December 2003 Botanical Name Common Name Absolute Cover (%) Bacchans salicifolia * mule fat 4.7 OenothOra elata Spp. hirsutissirna * evening primrose ' .3.8 Salix exigua * ' ' narrow-leaved willow . 3.5 Malvella leprosa' * , , alkali mallow ' - 2.9 Anernopsis califomica * yerba mansa - . 2.6 Arternisia douglasiana * - '. •Dougiasmugwort . . ' -' - 2.6 - Pluchea sericea * arrow weed - ' ' 2.4, Encelia califomica * , ' coastal sunflower Epilobiurn cilia turn willow herb 1.6; Salix lasiolepis * arroyo willow 1.3 B'accharis pilularis * , coyote bush ' - 1.2. '- Heterotheca grandiflora * telegraph weed 0 5 Solanurn douglasii * ' . black nightshade ' ' . 0.5 Brassica nigra black mustard 0.2 Pluchea odorata * salt marsh fleabane 0 2 Picns echioides bristly ox tongue 0.1 Percent Total Cover ' . . . .. '135.8 Percent Native cover' ' . ' :' 1355 Percent Nonnative Cover 0.3 II Ell * Indicates species native to California - Nomenclature follows the Checklist of the Vascular Plants of San Diego County 31d edition by Michael 'G...,. Simpson and Jon P Rebman San Diego State University and San Diego Natural History Museum Tree and Shrub Heights r The tree and shrub height success standard for year 5 was achieved in-'2002. The specified tree' height success standard is 3.4 meters and the shrub height success standard is 1.8 meter Of, the 58 trees measured in the mitigation area, 22 were container trees (Table 2). The average ' height for container trees in the mitigation area was 4.0 meters, which achieves the height success standard of 3.4 meters. The.average tree height for all trees, including volunteers and unknowns, was 3.0 -meters; however, there was no success standard for volunteer and unknown trees. Of the 42 shrubs measured in the mitigation area, 9 were container shrubs (Table 2). The average height for container shrubs in the mitigation area was 3.1 meters which achieves the height' success standard of 1.8 meters. The average shrub height for all shrubs, 'including - volunteers and unknowns, was 2.5 meters; however, there was no success standard for volunteer and unknown shrubs. . •- Trees Botanical Name ,-.-Cbrnmon.Name Type Height . Sample Size Salix exigua Narrow-leaved willow Côntaine'r 2.7 9 Salix exigua . Narrow-leaved'willow Unknown 2.7 . 3 Salix exigua Narrow-leaved willow Volunteer 2.1 29 Salix lasiolepis . Arroyo willow Container 5.3 13 Salix lasiolepis Arroyo willow Volunteer 2.5 . 4 Average for Container Trees . . . . . . 4.0 . 22 Average for All Trees . .. . 3.0 . 36 Total. . . 58 Shrubs Botanical Name Common Name Type Height Sample Size Baccharis pilularis Coyote bush. Volunteer 1.6 5 Baccharis salicifolia Mulefat •. Container 3.1 9 Baccharis salicifolia Mulefat Unknown '. 3.0 4 Baccharis salicifolia Mulefat Volunteer 3.4 . 24 Average for Container Shrubs 3.1 . 9' Average for All Shrubs .' . 2.5 33 Total 42 Ms. Sherri Howard City of Carlsbad, Olivenhain Riparian Mitigation Site: Year 6 December 2003 amec Table S OLIVENHAIN ROAD WETLAND MITIGATION AREA TREE AND SHRUB CONTAINER HEIGHTS (2002) 'Container Plant Success The container tree and shrub survival success standard for year 5 has been achieved The •' percent survival success standard for year 5 is 90 percent for container trees and 80 percent for container shrubs. No dead container trees or shrubs were located during the fifth year of the: mitigation area. S . S • , - Wetland Delineation Results • •' S • . S A total of 0.23 acre of jurisdictional wetland area was identified within the mitigation area.' The • limits of jurisdictional wetlands (coastal salt marsh/freshwater marsh) mapped are shown in Figure 2. The regulatory permits required that 0.16 acre of freshwater marsh be created at the mitigation site; however, there is a higher amount of acreage (0.23. versus 0.16 acre) because the boundary of the mitigation site (mitigation site easement) is greater than the area where the S S ' . 325400000-3605/3151-1203R1'26.doc • • - • Page Ms. Sherri Howard . . . City of Carlsbad Olivenhain Riparian Mitigation Site Year 6 December 2003 ame& 0.16 acre was created There is also 0.38 acre of southern willow scrub and 0.09 acre of upland riparian transitional habitat in the mitigation site Based on the wetland delineation process the City has met the obligations of the regulatory (USACE and CDFG) permits as presented in the dataforms and photographs in Attachment A Determination The City requests concurrence from the regulatory agencies that the City has fulfilled allof the requirements outlined in the regulatory permits as described in this letter report A final walk-through of the mitigation site will occur only if requested by the regulatory agencies upon receiving and reviewing this letter. report If no final wk-through is requested by the regulatory agencies the City will assume that their responsibility .o maintain and monitor the mitigation'.site under the regulatory permits no longer applies and that concurrence from the regulatory agencies that the mitigation site has met all success standards will have been granted Please contact Jessie Walker if you have any comments or questions The City will assume that the regulatory agencies concur with this arrangement unless we are notified to the contrary by 30 January 2004 Sincerely, AMEC Earth & Environmental, Inc ) Jessie Walker Natural Resource Specialist/Botanist JWvm Attachment Figure A-I, Coastal Salt Marsh/Freshwater Marsh at Soil Pit Number 1 Figure A-2, Soil Pit Number 1 Vegetation Community Figure A-3, Mottles in Soil at Soil Pit Number 1 Figure A-4 Coastal Salt Marsh/Freshwater Marsh at Soil Pit Number 2 Figure A-5 Southern Willow Scrub at Soil Pit Number 3 ••, •• •• cc File Copies (2) 325400000 3005/3151 1203R126 doc • - •. • : • Page 10 • V., 77 ? .7_ - . - • - 34 - :. :: •.- tt -P yit _4_ S7• 4 -, 4 -' - 7 .7.- .4 .- 4 (4 .4 : 34( 41.7 .7 4, 4 ' 4.7 4 1 - 7 q :v f, .77 : I ' - .7.7 . - • . . 1.. •.-: 4j4 ç • .7 - r I - l - ç-: I .7 FA j&1gcg lord, .444 - . - : '- ., 4 ''' 44 :•• ji '4:: - :• :'' :4 ol fj T .4 ce .4 14•• t,. - ,•- - - : 01 F 4 3 t 1 ,• - - .4 :~Tf--tat Soil Pit NumbiVi,"'k '5,4 I f •44 .4 •, •' - GRAPNICS/BoIogy/325400000_3005 Oluvenhain/A_1 Fh84 .- ti e X 141 , ) - 1) ' k. . -. ' -t i) - ci It t4/f Ilk kt ••4141 % vt - I ,iA '- •.\/, ;- '•• . '- . -;'r" I I ' "IX P I I' %tQt J 1 AMEX -: 5011. Pit Number Vegetation community -. 1 - S Mottles in Soil at Soil Pit Number 1 am GRAPHICS/Biology/325400000_3005 Olivenhain/A_3Fh8 kE 10, k *.j •, l Y I I..--.---- ' 2 - 'at.. Soil Pit Number .2, ________ ':' '!( f?e' •;.;;; - . - . SS '- •• I - •, I .' -. -•s .- .5r - / Sr — •r '' S S - - -. 5-, ;., S -. - • -r -s 5--4,-.••.' •... • S ¶ S S .5-, • •S '• - S .— . ;••_S•• - 5 . J- :- • •-- .5,5 - . . -. - • - -:- . - . : - -. • -, S •• •. ':' I / C * S --, •,,* S - :.:-. •- ...•- •;• S - 5 - -r, •i. ' •-' .5 -. 5 •' 5 5 • 5.. •5• I -, - I • - - S - - I S. • - - S .__.5•._•. • - S S - - •• S. • s • S • - -, J 5/ * ' '-•- I; . •_ •.: •, •: •.., • /•., '.' / S 5 -- ;-:- ---- S j //•4)/ -5 •S. 1) I Southern Willow Scrub at Soil Pit Number 3