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HomeMy WebLinkAbout; South Carlsbad Villiage Strom Drain Project; South Carlsbad Village; 1999-05-03WETLAND DELINEATION REPORT EOR THE SOUTH CARLSBAD VILLAGE STORM DRAIN PROJECT CITY OE CARLSBAD SAN DIEGO COUNTY, CALIFORNIA Prepared for: CITY Or CARLSBAD Z075 Las Palmas Drive Carlsbad, CA 92009 Contact: Douglas Helming (760)431-5999 Prepared by: DUDEK & ASSOCIATES, INC. Professional Teams for Complex Projects 605 Third Street Encinitas, California 92024 Contact: Anita M. Hayworth, Ph.D. (760) 942-5147 3 May 1999 Wetland Delineation Report + South Carlsbad Village Storm Drain Project, City of Carlsbad, San Diego County, California TABLE Or CONTENTS Section Page SUMMARY OF FINDINGS , ii 1.0 DESCRIPTION OF PROJECT 1 2.0 PURPOSE OF ASSESSMENT 1 3.0 ENVIRONMENTAL SETTING 1 4.0 METHODS 4 5.0 RESULTS 5 5.1 General Description of Wetland Habitat 5 5.2 Wetland Determination and Delineation 8 5.2.1 ACOE Jurisdiction 8 5.2.2 CDFG Jurisdiction 8 5.3 Wetland Functions and Values 8 6.0 DISCUSSION 9 6.1 Project Impacts 9 6.1.1 ACOE Impacts 9 6.1.2 CDFG Impacts 9 6.2 Regulatory Requirements 9 6.3 Mitigation 11 7.0 LITERATURE CITED 12 LIST OP FIGURES Figure 1 Regional Map 2 Figure 2 Vicinity Map 3 Figure 3. Wetland Delineation Map - Existing Channel 6 Figure 4 Wetland Delineation Map - Stormdrain Channel 7 Figure 5 Proposed Stormdrain Outfall and Riprap 10 DUDEK 1403-01 |& ASSOCIATES, INC.| miMforCamplaPmjtai May 3, 1999 Wetland Delineation Report • South Carlsbad Village Storm Drain Project, City of Carlsbad, San Diego County, California SUMMARY OF FINDINGS Implementation of the proposed South Carlsbad Village Storm Drain project, in the City of Carlsbad, San Diego County, California, would result in the permanent loss of approximately 0.63 acre (2,750 linear feet) of waters of the U.S., a habitat under the jurisdiction of the U.S. Army Corps of Engineers (ACOE). The habitat potentially affected is a linear stretch of an unvegetated drainage ditch along the A.T. & S.F. Railroad tracks within the City of Carlsbad. The site is located within an urban area of the city and is surrounded by ruderal, disturbed and developed lands. No species of plants or animals recognized as rare, threatened, endangered, or otherwise sensitive by the U.S. Fish and Wildlife Service (USFWS), California Department of Fish and Game (CDFG), or California Native Plant Society are present within or adjacent to the drainage area. The total area within the project under the jurisdiction of the ACOE is approximately 0.63 acres. Implementation of the proposed development would result in the permanent loss of 0.63 acre of jurisdictional habitat. Because impacts to waters are not less than a one-third acre and the project impacts more than 500 linear feet of waters, it requires review by the ACOE prior to use of one of the nationwide permits to cover impacts. No impacts to CDFG jurisdictional area would occur, thus a Streambed Alteration Agreement pursuant to Section 1603 of the California Fish and Game Code is not required. A Section 401 water quality certificate (or waiver) would be required from the California Regional Water Quality Control Board. Because of the low quality of the waters habitat to be impacted, it is recommended that a replacement be created at a ratio of 1:1 by area. Hence, it is recommended that 0.63 acre of wetland habitat be recreated or enhanced within the railroad right-of-way in the form of the creation of a swale vegetated with wetland plant species. DUDEK 1403-01 iSi ASSOCIATES, INC.May3,1999 Wetland Delineation Report • South Carlsbad Village Storm Drain Project, City of Carlsbad, San Diego County, California 1.0 DESCRIPTION OF PROJECT The South Carlsbad Village Storm Drain project involves construction of a backbone stormdrain system extending from Agua Hedionda Lagoon northward approximately 5,500 feet along the alignment of the San Diego Northern Railroad right-of-way to Oak Avenue (Figure •/). The proposed storm drain project will consist of an underground pipe from Oak Avenue to the discharge at Agua Hedionda Lagoon (Figure 2). The discharge structure will incorporate a short section of concrete-lined channel to convey the flows to the lagoon. Energy dissipators will be installed at the outfall. Riprap that was originally installed at the existing concrete outfall, and which has since then sunk into the substratum or washed away, will be replaced. No discharge of dredged and/or fill material to the lagoon is expected. Because the replacement of the existing riprap at the outfall with new riprap is considered a maintenance activity of a previously authorized fill, it is assumed to fall under the U.S. Army Corps of Engineers Nationwide Permit number 3. Other portions of the storm drain system are located within existing development and contain no biological issues to address. The proposed storm drain from Agua Hedionda to Oak Avenue consists of replacement of the existing dirt channel and possibly replacement of the existing pipe with the new line. The replacement of the existing dirt channel would result in the permanent loss of "waters of the U.S." which is under the jurisdiction of the U.S. Army Corps of Engineers (ACOE). 2.0 PURPOSE OF ASSESSMENT The purposes of this assessment are to determine the boundary of U.S. Army Corps of Engineers (ACOE) Section 404 jurisdiction and the boundary of the California Department of Fish and Game (CDFG) Section 1601-1603 jurisdiction within the study area, if any; to determine the acreage of impacts on these areas that would result from project implementation; and to determine the resultant permits or approvals required. 3.0 ENVIRONMENTAL SETTING The South Carlsbad Village Storm Drain project is located within the right-of-way of the A. T. & S. F. Railroad within the urban area of the City of Carlsbad. The area is west of Interstate 5 and east of Carlsbad Boulevard and runs between Agua Hedionda and Oak Avenue. The vegetation within the open, dirt channel, as it travels from Oak Avenue to Village Avenue is composed of ruderal vegetation or disturbed habitat and consists predominantly of non-native grasses and forbs as described in Section 5.0. The site is highly disturbed with little vegetation and only three DUDEK 1403-01 & ASSOCIATES, INC. l*mfruiimalTmmsfn Cam/tint Payerls Mty 3, 1999 Orange County Camp Pendleton Riverside County Fallbrook -7 O Oceanside Vista Carlsbad Project Site f Valley Center Escondido 1" = 8 Miles Encinitas o o Del Mar \ ^Rancno Santa Fe Mira Mesa La Jolla San Diego Rancho Bernardo / Poway Santee | La Mesa ^ . Lemon Grove Coronado . National City Imperial Beach Chula Vista Otay Mesa Tijuana Alpine Mexico South Carlsbad Village Storm Drain Project - Wetland Delineation Report Regional Map SOURCE: USGS 7.5 Minute Series, San Luis Rey Quadrangle 1" = 2000' South Carlsbad Village Storm Drain Project - Wetland Delineation Report Vicinity Map Wetland Delineation Report • South Carlsbad Village Storm Drain Project, City of Carlsbad, San Diego County, California native plant species present within the channel. Elevations onsite range from approximately sea level at the outfall to Agua Hediona to 40 feet above mean sea level. The open channel is approximately 2,750 feet long and is approximately 10 feet wide and approximately 6 feet deep. From Village Avenue south to the outfall to Agua Hedionda Lagoon, the storm drain is underground and consists of a 63-inch reinforced concrete pipe. The area above the concrete pipe is vegetated with non-native grasses and forbs or is devoid of vegetation. The outfall from the existing pipe to Agua Hedionda Lagoon consists of a concrete-lined channel, app'roximately 200 feet in length. A riprap field at the end of the outfall was originally in place to serve as protection and for energy dissipation. The riprap has now settled into the substratum. 4.0 METHODS A wetland determination was conducted on 30 May 1997 by Dudek & Associates, Inc., habitat restoration specialist Jeff L. Thomas. During the survey, notes were taken on the wetland plant communities present. Boundaries between wetland communities were mapped on a 200-scale (1"=200') topographic map. The U.S. Army Corps of Engineers Wetland Delineation Manual (1987) was used to determine whether jurisdictional wetlands occurred within the study area. The manual requires that positive indicators of hydric soils, wetland hydrology, and hydrophytic vegetation all be present to classify an area as a jurisdictional wetland. Other "waters of the United States," as defined by the ordinary high water mark of streams or drainages, also were identified and mapped in the field. Typically, where a predominance of hydrophytic vegetation is present, additional data on soils and hydrology are collected, and a wetland data form is completed. However, owing to the absence of a predominance of hydrophytic vegetation outside the ordinary high water mark of the deeply incised channel, no wetland data forms were completed and no soil pits were excavated. Isolated patches of hydrophytic vegetation were observed within the incised channel, and were noted as wetland portions of "waters of the U.S." The definition applied by the California Department of Fish and Game (CDFG) to determine the presence of wetlands is less objective than that of the U.S. Army Corps of Engineers (ACOE). Per CDFG, wetlands are defined as "a body of water that flows at least periodically or intermittently through a bed or channel having banks and supports fish or other aquatic life." 'This includes water courses having a surface or subsurface flow that supports riparian vegetation." Any area that met these criteria also was identified and mapped. DUDEK 1403-01 & ASSOCIATES, INC. i/nr Cm/lot Pnrjerls May 3, 1999 Wetland Delineation Report • South Carlsbad Village Storm Drain Project, City of Carlsbad, San Diego County, California 5.0 RESULTS 5.1 General Description of Wetland Habitat Areas under the jurisdiction of the ACOE and/or the CDFG are illustrated in Figures 3 and 4- Soils within the drainage are mapped as Marina loamy coarse sand, 2-9 percent slopes (MIC) (Bowman 1973). Jurisdictional area onsite consists of a deep, incised maintained channel draining from north to south within a City of Carlsbad right-of-way parallel to the railroad alignment. The drainage consists of two open channels; an approximately 2,750-foot earthen channel between Oak Avenue and Village Drive (Figure 3), and a 200-foot concrete channel and outfall at Agua Hedionda Lagoon (Figure 4). Stormwater and urban runoff are carried between the channel sections via a buried storm drain pipe. Both sections of the open channel consist of a deep (6-8 feet below the surrounding land surface), incised, narrow (10 feet wide) drainage. The northern channel section is predominately vegetated by ruderal non-native species or is unvegetated, with channel banks occupied by ruderal or weedy habitat. The bottom of the drainage supports two isolated patches of freshwater marsh (0.08 acre total), i.e., cattails (Typha latifolia) and willow weed (Polygonum lapathifolium), and scattered individuals of castor-bean (Ricinus communis), curly dock (Rumex crisyus), umbrella sedge (Cyperus involucratus), and western ragweed (Ambrosia psilostachya) amidst a wide distribution of prickly lettuce (Lactuca serriola), wild radish (Raphanus sativus), Mexican tea (Chenopodium ambrosioides), garland (Chrysanthemum coronarium), and Bermuda grass (Cynodon daaylon). Three of the plant species observed in the channel are obligate wetland species: cattail, umbrella sedge, and willow weed, of which only the willow weed is a native plant species. It is unknown whether or not portions of the drainage supported riparian habitat historically. From Village Avenue south to the outfall to Agua Hedionda Lagoon, the storm drain is underground and consists of a 63-inch reinforced concrete pipe. The area above the concrete pipe is vegetated with non-native grasses (brome and wild oats), western ragweed, castor-bean, and wild radish. The outfall from the existing pipe to Agua Hedionda Lagoon consists of a concrete-lined channel, approximately 200 feet in length. There is no wetland vegetation within the concrete channel. Adjacent to the outfall, the habitat consists of developed areas, disturbed habitat, ruderal vegetation, and salt marsh. The salt marsh habitat is dominated by pickleweed (Salicornia virginica) and the location of the salt marsh was flagged and surveyed to accurately place its location. DUDEK 1403-01 & ASSOCIATES, INC. Pmfmionat Tronu/w Cmnplfx Projects May 3, 1999 f : t t . : J »J t t .3 Vegetation Types: FWMl Freshwater Marsh Unvegetated, earthen channel (10' wide X 6' deep) TOPO SOURCE: City of Carlsbad, Sheets 38 & 49 Scale In Feet South Carlsbad Village Storm Drain Project - Wetland Delineation Report Wetland/Waters Delineation Map - Existing Channel FIGURE Vegetation Types: I SMI Salt Marsh I OW| Open Water iRUDl Ruderal I DH | Disturbed Habitat |DEV| Developed BASE TOPO SOURCES: City of Carlsbad, Sheet 60 and Malcolm Pimie Unvegetated Concrete Channel (10' wide X 8' deep) Scale in Feet South Carlsbad Village Storm Drain Project • Wetland Delineation Report WetlandfWaters Delineation Map - Storm Drain Outfall Wetland Delineation Report • South Carlsbad Village Storm Drain Project, City of Carlsbad, San Diego County, California 5.2 Wetland Determination and Delineation 5.2.1 ACOE "Jurisdiction U.S. Army Corps of Engineers wetland habitat is present onsite consisting of freshwater marsh. The incised channel, an intermittent blue line stream, represents "waters of the United States" which is also under the jurisdiction of the ACOE. Total ACOE jurisdiction onsite is approximately 0.63 acre of unvegetated and vegetated channel. 5.2.2 CDFG lurisdiction CDFG jurisdiction is typically calculated based upon the area of riparian vegetation. Because the channel supports no significant riparian vegetation and there is no evidence of aquatic wildlife, no CDFG jurisdictional wetland occurs in the study area. 5.3 Wetland Functions and Values A formal wetland functions and values analysis was not performed. Wetland habitat within the study area is expected to have low value as wildlife habitat owing to its highly disturbed condition and the lack of riparian vegetation. The drainages support exceedingly few hydrophytic plant species (e.g., Polygonum lapathifolium, Typha latifolia), and few birds forage within it. None of the typical southern California riparian birds (e.g., vireos, flycatchers, woodpeckers) are present. Birds species observed most commonly include house finch (Carpodacus mexicanus), lesser goldfinch (Carduelis psaltria), and mourning dove (Zenaida macroura). The channel probably has few biotic functions. No species of mammals were detected within the vicinity of the drainage. Mammals likely to be present include those species adapted to disturbed or urbanized landscapes, including Virginia opossum (Didelphis virginica), cottontail (Sylvilagus sp.), striped skunk (Mephitis mephitis), California ground squirrel (Spermophilus beecheyf), and introduced rats (Rattus sp.). No sensitive, threatened, or endangered species were observed in the drainage. DUDEK 1403-01 & ASSOCIATES, INC. l-mfrtsioml Ttaaa far C»m/ifa ftrya-u Mfly 3, 1999 Wetland Delineation Report *• South Carlsbad Village Storm Drain Project, City of Carlsbad, San Diego County, California 6.0 DISCUSSION?m> m 6. \ Project Impacts "SS •an Impacts to waters of the U.S. would result from the implementation of the South Carlsbad Village Storm Drain project. The entire open channel between Village Place and Oak Avenue would be replaced with a pipeline to transport storm runoff to Agua Hedionda. The existing dirt channel ** would be filled to match surrounding grade (Figure 5). Impacts also would occur at the outfall for the „, replacement of the existing riprap. *»6.1.1 ACOE Impacts••<»** *» Approximately 0.63 acre of ACOE jurisdictional waters would be permanently lost by removal of the unvegetated channel. The area is represented primarily by disturbed, non-vegetated habitat. A total of 0.08 acre of freshwater marsh would be impacted. The total impact to ACOE jurisdiction at the outfall for replacement of riprap is 300 square feet (0.007 acre) based on the measurement at the highest tide height (+4.91 feet). 'rfynOi 6.1.1 CDFG Impacts " No CDFG jurisdictional wetlands would be permanently lost by project implementation. 6.2 Regulatory Requirements The discharge of dredge or fill material (temporary or permanently) into areas delineated as "waters ** of the United States" requires authorization from the ACOE pursuant to Section 404 of the Clean Water Act. 'Waters of the U.S." as defined in CFR 328.2 includes all waters or tributaries to waters, including wetlands, streams, dry washes, seasonal drainages, and other aquatic habitats. Activities that involve regulated discharge of dredge or fill material include grading, placing of riprap for erosion control, pouring concrete, laying sod, and stockpiling excavated material. Activities that generally ^ do not involve regulated discharge, if performed in a manner to avoid discharge, include driving pilings and some methods of vegetation clearing. •«*#<t «*- Because the placement of the riprap at the end of the storm drain outfall is considered a maintenance activity, the use of NWP 3 is appropriate and no notification or mitigation is required. The total impact to ACOE jurisdiction at the outfall is 300 square feet (0.007 acre) based on the measurement — at the highest tide height (+4.91 feet). 1403-01 & ASSOCIATES, INC. frofananal Tan, for Campk* Pm/retl May 3, 1 999 Vegetation Types: I SM| Salt Marsh I OW| Open Water [RUDl Ruderal I DH I Disturbed Habitat I DEV| Developed BASE TOPO/IMPROVEMENTS SOURCE: Malcolm Pimie GUA h 100 Scale In Feet South Carlsbad Village Storm Drain Project - Wetland Delineation Report Proposed Storm Drain Outfall and Riprap FIGURE -: Wetland Delineation Report *• South Carlsbad Village <- Storm Drain Project, City of Carlsbad, San Diego County, California m Total ACOE jurisdiction to be impacted for the removal of the unvegetated channel is 0.63 acre. The ACOE has 36 nationwide or general permits (NWPs) that pre-authorize specific minor discharges. "* Generally, use of these NWPs does not require review by the ACOE or other federal agencies. If „, endangered species or significant cultural resources occur on the property and are not adequately mitigated, the activity is not considered pre-authorized and ACOE has the discretionary authority to require an individual permit. The individual permit process involves public comment on the ** proposed activity and can last 180 days or longer. Because impacts to ACOE jurisdiction are greater m than one-third acre and also greater than 500 linear feet, notification of the ACOE is required. '"" The applicant must also obtain a Section 401 water quality certification (or waiver) from the •** California Regional Water Quality Control Board. *»m No impact to CDFG jurisdictional wetlands will occur as a result of the project, thus a CDFG 1603 agreement will not be required. *m m 6.3 Mitigation •*m Mitigation for impacts to ACOE jurisdiction takes several forms, including (1) avoidance of impacts; m (2) reduction of impacts; or (3) compensation for impacts. The proposed project would impact a « total of 0.63 acre of jurisdictional waters of the U.S. The ultimate determination of mitigation, including the ratio, is subject to the discretion of the agencies. However, the mitigation ratio should be commensurate with the low quality of wetlands onsite. *£SS» «. It is recommended that impacts to waters be mitigated at a ratio of 1:1 by area. Hence, 0.63 acre of wetland habitat should be created/revegetated within the area. It has been suggested and confirmed by the project civil engineer that a swale could be constructed within the railroad right-of-way from ** Oak Avenue to approximately 100 feet north of Tamarack Avenue for a total length of 3,650 feet. „, The swale could be constructed to be a total of 10 to 11 feet wide with an average mean high water mark width assumed to be 8 feet. This created swale is proposed to be vegetated with salt grass (Distichlis spicata), which is a FAC WET plant species. This would create a total mitigation acreage — of 0.67 acre. •a No mitigation is required for the replacement of the riprap at the end of the concrete outfall to Aqua Hedionda. DUDEK 1403-01 & ASSOCIATES, INC. Pmfniimal Tarn far Cnmpkx Fmjrrls Mity 3, 1999 11