HomeMy WebLinkAbout3338; Agua Hedionda & Calavera Creek Dredging; Agua Hedionda & Calavera Creek Wetland; 2006-01-01WETLAND DETERMINATION AND DELINEATION REPORT FOR AGUA HEDIONDA AND CALAVERA CREEKS Prepared for: City of Carlsbad Department of Public Works-Engineering 1635 Faraday Avenue Carlsbad, CA 92008-73 14 Phone: 760.602.2720 Fax: 760.602.8562 Contact: David Hauser Prepared by: EDAW, Inc. 1420 Kettner Boulevard, Suite 620 San Diego, CA 92 10 1 Phone: 619.233.1454 Fax: 619.233.0952 Contact: John Messina January 2006
TABLE OF CONTENTS Section Page PROJECT DESCRIPTION AND LOCATION .......................................................................... 1 METHODOLOGY .................................................................................................................. 1 EXISTING CONDITIONS .......................................................... - .............................................. 5 Topography ...................................................................................................................... 5 Agua Hedionda Creek ......................................................................................... 5 Calavera Creek ........................................................................................................ 5 Detention Basin BJB ............................................................................................. 6 Soils ................................................................................................................................ 7 Riverwash .......................................................................................................... 7 Salinas Clay Loam ................................................................................................ 7 Huerhuero Loam .................................................................................................... 8 Tujunga Sand .......................................................................................................... 8 FEDERAL AND STATE REGULATORY APPLICABILITY ................................................... 8 Section 404 of the Clean Water Act ................................................................................... 8 Section 401 of the Clean Water Act ................................................................................ 10 Section 1600- 16 16 of the California Fish and Game Code .............................................. 10 RESULTS .................................................................................................................................. 1 1 Agua Hedionda Creek ....................................................................................................... 1 1 Calavera Creek ................................................................................................................ 12 Detention Basin BJB ........................................................................................................ 17 SUMMARY .................................................................................................................................. 20 LITERATURE CITED . . . . .. . . . . . .. .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 APPENDIX A - Wetland Delineation Field Forms Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report Page i 05080162 Aguo Hediando Wetland Delineation.doc 2/1/06
LIST OF FIGURES Page 1 Regional Location Map .................................................................................................... 2 2 Project Location .............................................................................................................. 3 3 Agua Hedionda and Calavera Creeks U.S. Army Corps of Engineers and ........................................ California Department of Fish and Game Jurisdictional Areas 13 ........................................................................ 4 Agua Hedionda Creek (2002 Study Area) 15 5 Willow Riparian Forest along Agua Hedionda Creek between the El Camino Real and Cannon Road Bridges ........................................................................................ 16 ............................. 6 Wetlands and Unvegetated Waters of the U.S. along Calavera Creek 18 7 Wetlands within Detention Basin BJB and Unvegetated Waters of the. U.S. ........................... along Calavera Creek at the Culvert Outlet from Detention Basin BJB 19 LIST OF TABLES Table - Page ...................... 1 ACOE and CDFG Jurisdictional Waters, Wetlands, and Riparian Habitat 11 Page ii Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report 05080162 Agua Hedioh Wetland Delinearion.doc 2/1/06
f': :A PROJECT DESCRIPTION AND LOCATION The City of Carlsbad proposes to dredge and improve portions of the Agua Hedionda and Calavera creek channels located within and adjacent to the Rancho Carlsbad Mobile Home Park (RCMHP). The project is needed to restore 100-year flood protection to as many RCMHP residents as feasible. Currently, more than 300 lots would be inundated by a 100-year storm event. The proposed project involves dredging the Agua Hedionda and Calavera creek channels, removing or modifying the existing weir wall structure at the Detention Basin BJB, modifying the outlet to the Detention Basin BJB culvert, modifying existing piers under the Cannon Road and El Camino Real bridges, stabilizing the channel and bank of Calavera Creek, and mitigating for impacts to existing environmental resources. The project is located in the northeast section of the city of Carlsbad, along Agua Hedionda and Calavera creeks, immediately west of the intersection of El Camino Real and Cannon Road, to approximately 3,000 feet to the east. The study area includes Agua Hedionda Creek, from just to the north of the Cannon Road Bridge to Rancho Carlsbad Drive to the east. The study area includes Calavera Creek from its confluence with Agua Hedionda Creek to the Detention Basin BJB, east of the intersection of College Boulevard and Cannon Road (Figures 1 and 2). METHODOLOGY On August 26, 2005, EDAW botanist John Messina conducted a routine wetland and waters determination and delineation of Agua Hedionda and Calavera creeks as well as an existing storm water detention basin (Detention Basin BJB). This determination and delineation was conducted pursuant to Section D Subsection 2 "Onsite Inspections for Routine Determinations for Areas Equal to or Less than 5 Acres in Size" of the U.S. Anny Corps of Engineers (ACOE) Wetland Delineation Manual (Environmental Laboratory 1987). A wetland determination and delineation had previously been prepared by RECON (2002) for that portion of Agua Hedionda Creek to the east of the El Camino Real Bridge. RECON'S delineation also included the confluence of Agua Hedionda and Calavera creeks. For these areas EDAW verified the previous wetland determination and delineation. This verification consisted of a survey of the area delineated by RECON to observe whether the existing conditions of Agua Hedionda Creek had substantially changed since the time of the RECON report. A formal routine determination and delineation was not conducted for the area encompassed by the RECON report. For a detailed description of the methodology used for the previous delineation, refer to the RECON report (2002). Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report Page 1 05080162 Agua Hediondo Wetland Delineation.doc 2/1/06
/ ORANGE /" COUNTY I., Figure 1 Regional Location Map w No Scale -- Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report P:UOOnOS080162 Agua HedionL Welland Delinca~h\ffinphiu\Figura\FigImup.Ihl I @ndyd) 9/13/05
Source: USGS, San Luls Rey Quadmngle Fieure 2 2000 Feet - CI a a2OO0 Project Location Scale: 1 : 24.000: 1 Inch - 2.000 feet Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report ?OOSllMMO162.4g1ru Il&rtdcr I~~ladDrllnrurlu11~5GIP~bLrdlB&' %brg' &lq.nml (E.Couglrlbd 9/IlMS
The routine determination method requires an examination for the presence of wetland indicators for hydrophytic vegetation, hydric soils, and wetland hydrology. With the exception of some atypical situations, the ACOE guidelines require the presence of a positive wetland indicator for each parameter (e.g., vegetation, soil, and hydrology). Observation points were selected along Agua Hedionda and Calavera creeks, and the Detention Basin BJB in the different vegetation communities within these features. Observation points were located in obvious wetland and nonwetland areas to determine the wetland-nonwetland boundary. A positive wetland determination was made for those observation points that exhibited positive wetland field indicators for each of the three parameters: hydrophytic vegetation, hydric soils, and wetland hydrology. A positive "waters of the U.S." determination was made for areas that did not meet all three criteria, but had evidence of an ordinary high water mark (OHWM). Once identified, jurisdictional areas were mapped onto a 1" = 100' recent color aerial photograph. All observation points were surveyed to determine the percent dominance of hydrophytic vegetation. An area was determined to support hydrophytic vegetation if more than 50 percent of the dominant species were listed as obligate (OBL), facultative wetland (FACW), or facultative (FAC) species on the U.S. Fish and Wildlife Service's National List of Plant Species that Occzrr in Wetlands: 1988 California (Region) (Reed 1988). For plants that were not present on Reed's 1988 list, the 1996 National List of Vascular Plant Species that Occzrr in Wetlands (USFWS 1996) was used. Soil test pits were dug where feasible to determine the presence of hydric soil indicators such as reducing conditions, gleyed or low-chroma colors, organic streaking, etc. Additionally, information regarding the mapped soil series of the site was gathered fi-om the Soil Szrrvey of the San Diego Area, California (Bowman 1973). The mapped soil series was then referenced on the Field Oflce Oflcial List of Hydric Soil Map Units for the San Diego Area, California (SCS 1992) to determine if any of these soils are identified as either hydric soils or contained hydric inclusions. All observation points were also surveyed for the presence of wetland hydrological field indicators such as inundations, saturation, water marks, drift lines, drainage patterns, and sediment deposits. The Routine Wetland Determination Data Forms for this project are included as Appendix A to this report. Page 4 Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report OS080161 Agrru Hediondu Wetlar~d Deli~teu~ro~i,doc 2/1/06
In addition, the limits of California Department of Fish and Game (CDFG) jurisdiction were measured as the distance from the top of one bank of the drainage to the top of the adjacent bank or from the edges of the riparian canopy, whichever distance was greater. EXISTING CONDITIONS Topography Agua Hedionda Creek Agua Hedionda Creek is a U.S. Geological Survey (USGS) perennial blue line stream. Within the study area, the entire historical stream is depicted as channelized on the USGS San Luis Rey Quadrangle 7.5-minute series topographic map. From the El Camino Real Bridge to Rancho Carlsbad Drive the creek is entirely within the RCMHP. The stream has a natural channel bottom and banks. The stream channel supports herbaceous hydrophytic vegetation, dominated by non-native species. There is a very low cover of this herbaceous vegetation, approximately 10 percent, which is likely the result of periodic maintenance of the creek to reduce flooding. The banks of Agua Hedionda are also natural but support mostly non-native, ornamental trees and shrubs. There are several large remnant sycamores (Platanus racemosa) scattered along these banks. East of the El Camino Real Bridge, the stream is natural (except for the bridge support columns and riprap supporting the bridge on the banks) and supports willow riparian forest habitat. However, this portion of the creek is also depicted as channelized on the USGS San Luis Rey Quadrangle 7.5-minute series topographic map. Much of the study area is very flat and the gradient in Agua Hedionda creek is gradual. The elevation of Agua Hedionda Creek at the eastern end of the study area, i.e., Carlsbad Drive, is approximately 60 feet above mean sea level (AMSL). The elevation of Agua Hedionda Creek at the western end of the study area, i.e., Cannon Road Bridge, is approximately 40 feet AMSL. Calavera Creek Calavera Creek is a USGS perennial blue line stream. Within the study area, the historical stream has been channelized its entire length and is depicted as such on the USGS San Luis Rey Quadrangle 7.5-minute series topographic map. There are portions of Calavera Creek that were channelized with concrete, including both of the banks and the channel bottom. Much of this feature has been heavily damaged and is no longer functional, though large remnant slabs of concrete are still present within the creek. Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report Page 5 05080162 Aguo Hedionda Wetland Delineation.doc 2/1/06
The topography and stream gradient for Calavera Creek are very similar to Agua Hedionda Creek. The topography is flat and the stream gradient is gradual. The elevation of Calavera Creek at the eastern end of the study area, i.e., at the intersection of College Boulevard and Cannon Road, is approximately 60 feet AMSL. The elevation of Calavera Creek at the western end of the study area, i.e., its confluence with Agua Hedionda Creek, is approximately 40 feet AMSL. A review of the Soil Suwey San Diego Area, California (Bowman 1973) indicates that Agua Hedionda Creek at one time flowed much closer to Cannon Road than it currently does and the confluence with Calavera Creek was likely much more to the east than its present location. The channelization of Agua Hedionda within the RCMHP moved the historical stream south to its present location. It appears, fiom the aerial photograph base of the soil survey map, that the lower portion of the present Calavera Creek is now located at the lower portion of the historical Agua Hedionda Creek location. Just north of the intersection of College Boulevard and Cannon Road, Calavera Creek is natural. Detention Basin BJB Just west of Calavera Creek in the eastern portion of the study area is Detention Basin BJB. This basin was created in previous agriculture land as evidenced by the aerial photograph base used in the soil maps of the Soil Suwey San Diego Area, Calijornia (Bowman 1973). This area is also mapped as agriculture on the Multiple Habitat Conservation Program (MHCP) Vegetation Communities with Sensitive Species and Vernal Pools Map for the Sun Luis Rey Quad (SANDAG n.d.). The basin has a flat soft bottom and manufactured slopesherms. There is a concrete spillway on the southeastern berm of the basin to accommodate large storm flows fiom Calavera Creek. There is at least one ingress culvert into the basin. This culvert is located along the western slopeherm underneath College Boulevard. This culvert collects storm water flow from the development east of College Boulevard. There may be additional ingress culverts leading into this large basin. However, since only a small portion of this basin is within the study area, the remainder of the basin was not surveyed. There is one egress culvert along the southern berm of the detention basin that channels storm water fiom the detention basin into Calavera Creek. This portion of Calavera Creek is natural, with a soft bottom and banks. It is very likely to have been recontoured given the long-term adjacent intensive agricultural land use. Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report 05080162 Agua Hedionrlo Wetland Delinmt~on-doc 2/1/06
Soils- - There are four soil series that underlay the two creeks and Detention Basin BJB within the study area: Riverwash, Salinas, Huerhuero, and Tujunga. There are two soil phases of the Salinas present: Salinas clay loam 0-2 percent slopes and Salinas clay loam 2-9 percent slopes. There is one phase of the Tujunga series, Tujunga sand 0-5 percent slopes; and one phase of the Huerhuero series, Huerhuero loam 9-15 percent slopes. Below is a description of the soil series within the study area. Riverwash Riverwash occurs along the lower portion of Agua Hedionda and Calavera creeks, from just upstream of their confluence to the eastern end of the study area. As mentioned in the preceding section, it is assumed that the lower portion of Calavera Creek historically was Agua Hedionda Creek and the historical confluence of these two creeks was farther to the east. Riverwash (Rm) occurs in intermittent stream channels. The material is typically sandy, gravelly, or cobbly. It is excessively drained and rapidly permeable (Bowman 1973). This soil is listed on the County of San Diego's Hydric Soil Lists (SCS 1992) and is classified as a major component. A hydric soil is a soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part. This component meets the National Technical Committee for Hydric Soils (NTCHS) criterion that "the soils are frequently ponded for long duration or very long duration during the growing season" (NTCHS 1995). Salinas Clay Loam The eastern portion of Agua Hedionda Creek is underlain by Salinas clay loam 2-9 percent slopes. It is assumed that this portion of the creek is not the historical channel but was relocated to its present location during the channelization. No portion of the historical Agua Hedionda Creek appears to have been underlain by Salinas clay loam. The entire historical portion of this stream appears to have been underlain by Riverwash. The Detention Basin BJB to the northeast of the intersection of Cannon Road and College Boulevard is also underlain by Salinas clay loam 2-9 percent slopes. The Salinas series consists of well-drained and moderately well-drained clay loams that formed in sediments washed from Diablo, Linne, Las Flores, Huerhuero, and Olivenhain soils. ,The Salinas series occur on floodplains and alluvial fans and have slopes of 0-9 percent. The Salinas Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report Page 7 05080162 Agua Hed~onrlo Wetland De1ineation.doc 2/1/06
series does not appear on the County of San Diego's Hydric Soil Lists (SCS 1992) nor does it contain a hydric inclusion. Huerhuero Loam The Huerhuero loam 9-15 percent slopes occur along the eastern boundary of the Detention Basin BJB study area and includes that portion of Calavera Creek within the study area that is north of the culvert under Cannon Road. This soil series consists of moderately well-drained loams that have a clay subsoil. Huerhuero loams develop in sandy marine sediments. This soil does not appear on the County of San Diego's Hydric SoiI Lists (SCS 1992) nor does it contain a hydric inclusion. Tujunga Sand Lastly, the upper portion of Calavera Creek is underlain by Tujunga sand 0-5 percent slopes. The Tujunga series consists of very deep, excessively drained sands derived from granitic alluvium. These soils are on alluvial fans and floodplains and have slopes of 0-5 percent. The Tujunga series has hydric inclusions, the Riverwash inclusion and an unnamed inclusion that appear on the County of San Diego's Hydric SoiI Lists (SCS 1992). The criteria established by the NTCHS (1995) with which the Riverwash inclusion meets the hydric soil definition stated previously is "soils that are frequently flooded for long duration or very long duration during the growing season." The criteria established by the NTCHS (1995) with which the unnamed inclusion meets the hydric soil definition stated previously is "poorly drained or very poorly drained that have a frequently occurring water table at less than 1.5 feet from the surface for a significant period (usually more than 2 weeks) during the growing season if permeability is less than 6.0 inchesthour in any layer within 20 inches." FEDERAL AND STATE REGULATORY APPLICABILITY This section describes the federal and state applicable to wetlands. Section 404 of the Clean Water Act Section 404 of the Clean Water Act (33 USC $ 125 1-1387) is the primary statute regulating activities in jurisdictional waters. Section 404 of the Clean Water Act prohibits the discharge of Page 8 Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report 05080162 Agua Hedionda Wetland Delinmtion.doc 2/1/06
dredged or fill material into "waters of the U.S." without a permit from the ACOE. Waters of the U.S. encompass both wetland and nonwetland aquatic habitats, such as streams, rivers, lakes, ponds, bays, and oceans, and are defined as follows: "(1) all waters which are currently used, or were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide; (2) all interstate waters including interstate wetlands; (3) all other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which could affect interstate or foreign commerce including such waters: (i) which are or could be used by interstate or foreign travelers for recreational or other purposes; or (ii) from which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or (iii) which are used or could be used for industrial purpose by industries in interstate commerce; (4) all impoundments of waters otherwise defined as waters of the United States under the definition; (5) tributaries of waters identified in paragraphs (1) through (4) of this section; (6) the territorial seas; and (7) wetlands adjacent to waters identified in paragraphs (1) through (6) of this section . . ." (33 CFR 328.3[a]). As a result of a U.S. Supreme Court decision (Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers, No. 99-1 178, January 9, 2001), the ACOE does not have regulatory authority over many isolated intrastate waters. The ACOE defines wetlands as: "Those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas" (33 CFR 328.3[b]; 40 CFR 230.3[t]). The limits of wetlands are delineated based on the co-occurrence of wetland hydrology, plants (hydrophytic vegetation), and soils (hydric soils). In the absence of wetlands, the limits of ACOE jurisdiction in nontidal waters, such as rivers, streams, lakes, and ponds, extends to the om. Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report 05080162 Agua Hedionda Wetland Delineation.doc 2/1/06 Page 9
Section 401 of the Clean Water Act The Regional Water Quality Control Boards (RWQCBs) have primary authority for permit and enforcement activities under the Porter-Cologne Water Quality Control Act (Cal. Water Code 13000-13999.10) and Section 401 of the Clean Water Act. Section 401 of the Clean Water Act requires certification fiom the local RWQCB that a proposed project is in compliance with established water quality standards. Projects that have the potential to discharge pollutants are required to comply with established water quality objectives. The RWQCB reviews a project to determine whether the activity would comply with state water quality objectives and, subsequently, either issues a certification with conditions or denies the certification. No license or permit may be issued by a federal agency until certification required by Section 401 has been granted. Under the Clean Water Act, Section 404 permits are subject to RWQCB Section 401 water quality regulation. The ACOE cannot issue an individual or nationwide 404 permit until a 401 certification has been obtained fiom the RWQCB. Section 1600-1616 of the California Fish and Game Code Under Sections 1600- 16 16 of the California Fish and Game Code, the CDFG regulates activities that would alter the flow, bed, channel, or bank of streams and lakes. The limits of CDFG jurisdiction are defined in the code as the "bed, channel or bank of any river, stream or lake designated by the department in which there is at any time an existing fish or wildlife resource or from which these resources derive benefit." The California Code of Regulations (14 CCR 1.72) defines a stream as: "[A] stream is 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 watercourses having a surface or subsurface flow that supports or has supported riparian vegetation." In practice, the CDFG usually extends its jurisdictional limit to the top of the bank of a stream or lake, or outer edge of the riparian vegetation, whichever is wider. Riparian habitats (i.e., stream channels) do not always have identifiable hydric soils, or clear evidence of wetland hydrology as defined by the ACOE. Therefore, CDFG wetland boundaries often extend beyond ACOE wetland boundaries, which sometimes include only portions of the riparian habitat adjacent to a river, stream, or lake. Jurisdictional boundaries under Sections 1600- 16 16 may encompass an area greater than that under the jurisdiction of Section 404 (Cylinder et al. 1995). Page 10 Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report 05080162 Agua Hedionda Wetland Delineation.doc 2/1/06
RESULTS Agua Hedionda Creek As part of the 2005 wetland determination and delineation, a site verification of a 2002 wetland delineation was conducted. It was verified that conditions had not altered substantially within the study area from 2002. Agua Hedionda Creek is composed of a series of sandbars among the meandering active channel (Figure 3). Vegetation cover is extremely sparse, generally less than 10 percent total vegetation and is dominated by very low-growing herbaceous vegetation, though several individuals of very small red willows (Salix laevigata) were observed within the channel (Figure 4). Much of the vegetation on the slopes of the creek is non-native ornamentals, though several mature sycamore trees are present. The wetland determination and delineation conducted in 2002 is still accurate. Based on the 2002 delineation, a total of 3.8 acres of ACOE jurisdictional wetlands, 0.4 acre of ACOE non-wetland waters of the U.S., and 6.7 acres of CDFG jurisdictional riparian and wetland habitat occur within the Agua Hedionda Creek study area east of the El Camino Real Bridge (Table 1). The total ACOE jurisdictional area totals 4.2 acres. The CDFG jurisdictional area of 6.7 acres encompasses the ACOE wetlands and non-wetland waters of the U.S. The acreages in Table 1 reflect a combination of the areas delineated in 2002 and 2005. Table 1 ACOE and CDFG Jurisdictional Waters, Wetlands, and Riparian Habitat I Encompasses ACOE jurisdictional waters of the U.S. and wetlands. 2 Includes 3.8 acres of ACOE jurisdictional wetlands, 0.4 acre of ACOE non-wetland waters of the U.S., and 6.7 acres of CDFG jurisdictional habitat delineated in 2002; and the 0.9 acre of ACOE jurisdictional wetlands, 0.38 acre of ACOE non-wetland waters of the U.S., and 1.81 acres ofjurisdictional habitat delineated in 2005. Feature Agua Hedionda creek2 Calavera Creek BJB Basin Total Area (acres) The 2005 routine determination and delineation of Agua Hedionda Creek included a study area from the El Camino Real Bridge to approximately 100 feet northwest of the Cannon Road Bridge. Though this portion of the creek was channelized, this portion of the creek supports mature willow riparian forest since periodic maintenance activities have not been recently Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report 05080162 Agua Hedion& Werlond Delinearion.&c 2/1/06 Page 11 CDFC Jurisdictional ~rea' 8.5 1 2.15 0.76 1 1.42 ACOE Jurisdictional Area Waters of the U.S. 0.78 0.44 0.02 1.24 Wetlands 4.70 0.63 0.38 5.71 Total 5.48 1.07 0.40 6.95
conducted along this portion of the creek, allowing mature vegetation to develop. Arroyo willow (Salix lasiolepis) and shining willow (Salix Iucida ssp. lasiandra) were the two dominant species observed within the study area Figure 5). This habitat meets all three ACOE wetland field criteria and thus qualifies as ACOE jurisdictional wetland. The periphery of this habitat within the study area occurs on riprap. Though the riprap would not qualifl as soil, it is assumed that hydric soil likely underlies the riprap. This riprap may encompass the historical OHWM and the extent of ACOE wetlands was mapped to the edge of this habitat within the study area. There is no vegetation beneath either the El Camino Real or the Cannon Road bridges. However, both of these areas would qualiQ as ACOE jurisdictional waters of the U.S. Underneath the El Camino Real Bridge there is a low-flow channel with an OHWM. In this area, the OHWM is confined to the middle span of the bridge and does not extend beyond the two sets of support columns. Underneath the Cannon Road Bridge, the creek is a braided convoluted channel with flow occurring. The entire area of the channel underneath the Cannon Road Bridge qualifies as ACOE jurisdictional waters of the U.S. As such, a total of 0.9 acre of ACOE jurisdictional wetlands and 0.38 acre of ACOE non-wetland waters of the U.S. occur within the Agua Hedionda Creek study area west of the El Camino Real Bridge (Table 1). The CDFG jurisdictional area encompasses all the ACOE waters and wetlands. Since the limits of the ACOE jurisdiction were assessed to the edge of the riparian canopy, the ACOE and CDFG jurisdictional areas are identical for this portion of the study area. A total of 1.8 1 acres of CDFG jurisdictional waters, wetlands, and riparian habitat occur within this portion of the study area (Table 1). The acreages in Table 1 reflect a combination of areas delineated in 2002 and 2005. Calavera Creek The study area for Calavera Creek occurs south of Cannon Road and within the RCMHP. The portion of the creek within the study area north of Cannon Road is described within the Detention Basin BJB subsection below. Calavera Creek is a perennial stream. The source of the flow observed in this portion of the creek was from a brow ditch that runs on the north side of the road from the residential facilities of the RCMHP to the tennis court and RV parking lot (Figure 3). This brow ditch contained flowing water at the time of the survey but the ultimate source of this water is unknown. This source of water is what likely allowed for hydric soil conditions observed along this portion of Calavera Creek. The upper portion of Calavera Creek is ephemeral and surface water (flowing or ponded) andor hydric soil field indicators were not observed during the determination. Page 12 Agua Hedionda and Calavera Creeks Wetland Determination and Delineation Report 05080162 Agua Hediondo IYerland Delineation.doc 2/1/06