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Home My WebLink About3338; Agua Hedionda & Calavera Creek Dredging; Calavera Hills Project Site/Agua Hedionda Channel; 2000-02-20WETLAND DELINEATION REPORT FOR THE CALAVERA HILLS PROJEa SITE -. * CARLSBAD, CALIFORNIA - .+ -A ,,- * Prepared for PLANNING SYSTEMS 1530 FARADAY AVENUE, $UTE 100 CARLSBAD, CA 92008 BIOLOGIST RECON NUMBER 3225B FEBRUARY 29,2000 1927 FI Avenue, Suite 200 San Diego, CA 921 01 -2358 61 9 1 308-9333 fax 308-9334 TABLE OF ,CONTENTS Summarg of Findings u I Introduction Methads A. Hydrophyiic Vegetation B. Hydrology C. Hydric Soils ' D. Other Jurisdictional Waters 'Results of Field Data A. Vegetation B. Hydrology C. St& Wetland Determination A. Areas Considered Wetlands B. Other Jurisdictional Waters References Cited FIGURES 1: Regional location of the project 2: Projectvicinitymap 3: Existing vegetation communities 4: Jurisdictional waters of the U.S. 1: Riparian woodland community on Calavera Cd 2: Cismontane alkali marsh community dominated by spiny rush 3: Freshwater marsh habitat at the edge of a riparian scrub community 4: Non-wetland jwidctiond drainage in coastal sage scrub habitat ATTACHMENT 1: Fielddataforms Summary of Findings A wetland delineation was conducted on the Chvera Hills project site, which-is located in the northeast quadrant of the city of Carlsbad. There are three components to the Calavera Hills project the Master Plpn Phase H, the formation by the City of Cadsbad of a Bridge and Thoroughfare District No. 4 for thc extensions of College Boulevard and Cannon Road, and the construction of two detention basins by the' City of Carlsbad to control flooding impacts within the Calaveras Creek watershed. A total of 30,2 acres of wetlands and 1.6 acres of non-wetland jurisdictional waters of the U.S. were delineated on the entire projsct site. Any impacts to these jurisdictional waters would be cansidered siflicant and =quire the appropriate permits and mitigation. A U.S. Arrny Corps of Engineers (USACE) Section 4.04 permit under the Clem Warn Act, Regional Water Quality 401 ~e~cate or waiver, and Califok Dephent of Fish and Game (CDFG) streambed alteration agreement (Section 1600) must be obtained prior to any impacts to jurisdictional waters or streambed. The interpretation of the data in this wetland delineation report and the conclusions drawn rrre subject to review and approval by th National Resource Conservation Service (NRCS) since the project site contains agricuItural lands. The USACE would make find jurisdictional dekmhtion based on the recommendation of the NBCS . Introduction The Calavera Hills Master Plan Phase II and Bridge and Thoroughfare District No. 4 project sik is located in the northeast quadrant of the city of Carlsbd (Figures 1 and 2). The site is south of State Route 78 (SR-78), east of El Camino Real, and noah of PaEomar Airport Road. Wetland delineation data ztnd background infodon required for envhmmental " analysis by USACE, CDFG, and the City of Cslrlsbad under the California ~~tal , Quality Act (CEQA) are included in this report. The biological resources report for tfre Calavera Hills projwt site (RECON 2000) contains all other biological information for the project. Methods The methodology for delineating wetlands used for this report folIows guidelines set forth by USACE (1987). Three criteria must be fulfilled in order to consider an area a jurisdictional wetland: (1) the presence of hy drophytic vegetation; (2) presence of wetland hydrology; and (3) the presence of hydric soils. Atypical wetland areas REIN I' m07zz7T 4.1 1 FIGURE 1 - Regional Location of the Project - M:jobsUZZSe!gapbics\feghd.cdr - .y" <'. -> :-Q.>'-- 2 4.- 3: *.*-... .-.J,. ;:rL .-.:;+ > I.. , . .. ,, ,; :?:. '.'.r;-rT.- ... r-. . . . . -- .-'m .. . ;;-! ?,' '2:$~@ 5 ,.( ::- 2;-e ?. ., 5$.&&&*9 ~ .,..,,,..,. \* ::+ . ,,.- - < . . %.$> k;yj @ .,::::<:> ,, .; ;, -> % ..: ..<.-7: .?;;.;%c A+> .:x$ ~, :.;.: $,+-;;;, : ,<w&T; ..i% ., : ~, ,.-;-,. . - ,.- < . ., .-., ...: sri;:.: ;'% ?;;, 2: .xi.. :-.* . . I., b>,A, ,*-.' . ...LT +?&kt m k:7,-a I - a* (disturbed wetlands) and problem area wetlands (e.g., seasonal wetlaads) my lack one or more of the three criteria but could still be considered wetlands if brackgrod u information on the previous condition of the area and field observations indicate that the . missing wetland criteria were present before the disturbance and would occur at the site . under normal circumstances. Tbe wetland delineation was conducted by RECON biologist, Jennifer Hodge on December 13,1999 and January 5 and 19,2000. A routine on-site deta tion method (USACE 1987) was used to gather field data at potential wetland streas on the project site. In addition, areas that displayed a prominent ordinary high water mark were also evaluated as potential nm-wetland jurisdictional waters or disturbed wetland. In August 1W8, a wetland delineation was conducted on Cantarini Ranch, which overlaps the central and southeastern portion of the Bridge ad Thoroughfare District and mtiw Basins (RECON 1999). Jurisdictional at ions from that report were ded in the field and incorporated into this document. A. Hydrophytic Vegetation Hydrophytic vegetation is defined as '?he sum total of mscrophytic plant life growing in ' water or on a substrate that is at least periodically deficient in oxygen as a result of ' excessive water content" (US ACE 1987). The potential wetland areas wem surveyed by walking the proposed project site and making observations of those areas exhibiting . chmteristics of jurisdictionaI waters or wetlands. Vegetation units with the potential to be wetlands were examined. The dominant plant species for each vegetation stratum (i.e., tree, shrub, herb, and vine) within the unit was determined, and the relative canopy cover was visually estimated. The dominant species from each stratum were then recorded on a summary data sheet along with the associated wetland indicator status of those specid. The wetland indicator status of each dominaut species was determined by using the list of wetland plants for California provided by the U.S. Fish and Wildlife Service (1997). 4,. The hydrophytic vegetation criterion is considered fulfilled at a Iocation if gmkr than 50 percent of all the dominant species present within the vegetation unit have a wetland indicator status of obligate (OBL), facultative-wet (FACW), or facultative VAC) (USACE 1987). An OBL indicatar status refers to plants that have a 99 pcent probability of murring in wetlands under natural conditions. A FACW indicatur status refers to plants that occur in wetlands (67-99 percent probability) but are occasionally found in non-wetlands. A FAC indicator status refers to plants that are equally likely to occur in wetlands or non-wetlands (estimated probabiJity 34-66 percent). B. Hydrology Hydrologic iafmation for the site was obtained by locating bbblue-lioen streams an U.S. . Geological Survey (USGS) topographic maps, reviewing gromdwater table elevation information hm soil surveys, and direct obsewations of hydrology indicators in the field . (e.g., inundation, ddl lines, sediment deposits, and drainage patterns). Evidence of flows, flooding, and ponding were recorded and the frequency and duration of these events were inferred. The wetland hydrology criterion is considered fulfilled at a location based upon the conclusions iaferred from the field observations, which indicate that an area has a high probability of being inundated or sahmted (flooded or ponded) long enough during the growing season to develop anaerobic conditions in the surface soil en-= especially the mot zone (US ACE 1987). Hydric Soils Sample points were selected within each vegetation unit whexe the apparent boundary between wetland and upland was inferred based on chmges in the compositian of tb ' vegetation. Soil pits were dug to a depth of at least 18 inches, as necessary, to determine . soil color, evidence of soil saturation, depth to groundwater, and indicators of a reducing soil environment (e.g., mottling, gleying, sulfidic odor). Soil profiles exposed by these . pits wm compared to known profiles for soil types occurring in the region by referencing the local soil survey (U.S. Department of Agriculture WSDA] 1973). The order, group, and series for the soils vent on the site were recorded. The hydric soil &&on is considered fulfilled at a lmation if sails in the area could b& infd to have a high groundwater table, evidence of prolonged soil saturation, or any indicators suggesting a long-term reducing environment in the upper 12 inch& of the sod -. pde. D. Other Jurisdictional Waters Drainages, or portions thereof, that lack hydrophytic vegetation and/or hyctric soils, but have distinct evidence of seasonal flows axe classified as nm-wetland jurisdictional waters. The extent of the observed ordinary high water mark, as defined by USACE under Section 404 of the Clean Water Act, is used to estimate the limits of these jurisdictional waters. Results of Field Data A description of the major vegetation units observed, soil types encountered, and a discussion of the local hydrblogy in the project area are presented below. Copies of the u field data forms summarizing information on vegetation, soils, and hydrology observed at each sample site are provided in Attachment 1. I Vegetation Figure 3 depicts the vegetation communities mapped on the Calavera Hills project site. Areas with hydrophytih vegetation and areas without hydrophytic vegetation were observed. Areas having hydropbytic vegetation, in general, were cansidered potential wehd sites. Areas without hydrophytic vegetation were considered upland, unless evidence suggested that a wetland or other jurisdictional water might mcm at the particular location. 1 Aress with Hydrophytic Vegetation a Rip~Woodland Approximately 15.3 acres of the Bridge and Thoroughfare District corridor (see Figure 3) and detention basin area of riparian woodland is located along a portion of Cdavera Creek, Agua Hedionda Creek, and an unnamed drainage. Photograph 1 shows an agricultural fkId that borders the riparian woodland community on Calavera Creek, Western sycamores (Platanus racemosa) and arroyo willow (Salix hiolepis) dominate the plant community with understory species composed of mule fat (BmcM salicifolia), mugwort (Artemisia douglasiana), giant ~ed (A& donax), castor bean (Ricinus communis), and poison hemlock (Conium tnamhhute). Western sycamore, arroyo willow, and mule fat are FACW plant species. Mugwort is a FAC+, castor bean a PAW (facultative upland), and poison hemlmk is a FAC plant species. Gnater than 50 percent of the vegetation within the riparian woodland communities on-site have a wetland indicator status of facultative or FACW; therefore, this habitat -1s the criteria of having hydrophytic vegetation. ,, .. b. Rip~Scrub Approximately 7.2 acres of riparian scrub are present within the Master Plan area and 3.3 acres are present within the Bridge and Thoroughfare District/Detentiw basin mas. The community designation includes both mule fat scrub and southern willow scrub habitats found along many of the drainages on-site. Mule fat and coyote bush dominate with giant reed, pampas grass (Co~aderia juhta), and curly-dock (Rumex crispus) commonly present. The southern willow scrub is dominated by arroyo willow, wbicb forms st canopy