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Jurisdictional Delineation: Waters of the United States and Streambeds
JURISDICTIONALDELINEATION:WATERS OF THE UNITEDSTATES
AND STREAMBEDS
Hidden Creeks EstatesLos Angeles County, California
Prepared for:First American Communities370 N. Westlake Blvd. #130
Thousand Oaks, California 91362
Contact: Mr. John Polito
Prepared By:Impact Sciences
803 Camarillo Rd., Suite ACamarillo, California 93012
(805) 437-1900
May 2007
Impact Sciences, Inc. i Hidden Creeks Estates860.001 May 2007
TABLE OF CONTENTS
Section Page
INTRODUCTION.......................................................................................................................................................1Project Description...........................................................................................................................................1
METHODOLOGY.......................................................................................................................................................7GPS Mapping ...................................................................................................................................................8
SITE DESCRIPTION...................................................................................................................................................8Watershed.........................................................................................................................................................8Topography ......................................................................................................................................................8Hydrology.........................................................................................................................................................9Soils..................................................................................................................................................................10Vegetation.......................................................................................................................................................10Functional Assessment of Jurisdictional Streams and Wetlands ............................................................11
DISCUSSION OF FINDINGS..................................................................................................................................12ACOE Waters of the United States and Wetland Areas (Section 404, Clean Water Act) andCDFG Streambeds (Sections 1600–1603, Fish and Game Code of California).......................................12
OFF-SITE RESOURCES ...........................................................................................................................................13
SUMMARY OF JURISDICTIONAL RESOURCES...............................................................................................22
REFERENCES............................................................................................................................................................23
APPENDICES
APPENDIX A – Site PhotosAPPENDIX B – Data Sheets
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Impact Sciences, Inc. ii Hidden Creeks Estates860.001 May 2007
LIST OF FIGURES
Figure Page
1 Project Location and Property Boundary ..................................................................................................22a Hidden Creeks – Overall Study Area and Project Site Boundary .........................................................32b Hidden Creeks – Drainage Detail ............................................................................................................142c Hidden Creeks – Drainage Detail (cont’d)..............................................................................................152d Hidden Creeks – Drainage Detail (cont’d)..............................................................................................162e Hidden Creeks – Drainage Detail (cont’d)..............................................................................................172f Hidden Creeks – Drainage Detail (cont’d)..............................................................................................18
LIST OF TABLES
Table Page
1 On-Site Soils Associated with Waters and Streambeds and their HydrologicalCharacteristics.............................................................................................................................................10
2 Ecological Functions Associated with Stream and Wetlands on Hidden Creeks EstatesProject Site...................................................................................................................................................12
3 Summary of Waters, Wetlands, and Riparian Corridors within the Property Boundariesof the Hidden Creek Estates Project Site.................................................................................................19
4 Summary of Jurisdictional Areas (acres) Hidden creeks Development Project Site .........................22
Impact Sciences, Inc. 1 Hidden Creeks Estates860.001 May 2007
INTRODUCTION
This jurisdictional delineation report documents the findings of field investigation on the 259-acre
Hidden Creeks Estates project site (and an off-site portion tentatively planned for road access) during
delineation of the extent of “waters of the United States,” including wetlands, under federal jurisdiction,
and streambeds under California Department of Fish and Game (CDFG) jurisdiction. The property is
located north of State Route 118 (SR-118) and west of the City of Los Angeles community, Porter Ranch
(Figure 1, Project Location and Property Boundary). Primary drainages on the project site include
Browns Canyon Wash and Mormon Canyon, both USGS blue line streams, and their associated
tributaries (Figure 2a, Hidden Creeks – Overall Study Area and Project Site Boundary). Situated within
the lower reaches of the southern Santa Susana Mountains, current land uses on the project site consist of
cattle grazing, equestrian facilities and riding trails, and television and movie production facilities.
While conducting the delineation, Impact Sciences, Inc., evaluated hydrology, soils, vegetation, ordinary
high water marks, stream banks, and riparian vegetation. Figures detailing the findings are included
throughout this report. Data sheets are included in Appendix B of this report.
Project Description
The Hidden Creeks Estates development is proposed as a gated community with 183 single-family
residential lots and five residential equestrian lots, associated roadways and infrastructure, a 17-acre
public park, and a new equestrian boarding facility. The majority of the residential lots will be clustered
on a graded, centralized plateau currently used for ongoing filming operations and grazing.
The proposal will result in significant alterations to existing drainages and on-site hydrology, as well as
direct impacts to federal and state jurisdictional aquatic resources. Hydrologic impacts include
alterations to the rate, volume, timing, and direction of surface runoff. Direct impacts to aquatic
resources include proposed construction within state-regulated riparian habitats and direct fill of both
federal wetlands and other “waters of the United States,” and state-regulated streambeds.
Project Location and Property Boundary
FIGURE1
860-001•07/06
SOURCE: Stantec Consulting, Inc. – November 2005
APPROXIMATE SCALE IN FEET
2400 1200 0 2400
n
CDFG
ACOE Wetland
ACOE
B
Study Area
oundary
Legend:
Mor
mon
Can
yon
Browns Canyon Wash
Figure 2b
Figure 2c
Figure 2e
Figure 2f
Mason Avenue (Proposed)
Figure 2d
Legend:
Project Boundary
Figure Index Location
Approximate Hidden Creeks Drainage Location
Hidden Creeks – Overall Study Area and Project Site Boundary
FIGURE2a
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SOURCE: Impact Sciences, Inc. – July 2006
APPROXIMATE SCALE IN FEET
500 250 0 500
n
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Impact Sciences, Inc. 4 Hidden Creeks Estates860.001 May 2007
U.S. Army Corps of Engineers
Federal regulation of “waters of the United States” stems from Section 10 of the Federal Rivers and
Harbors Act of 1899, enacted to regulate activities within navigable waters. Passed in 1972, the federal
Clean Water Act regulates discharges into “waters of the United States.” Section 404 of the Clean Water
Act regulates activities, including fills placed into wetlands that are adjacent to navigable waters.
“Waters of the United States” are defined in the Code of Federal Registration 33 CFR §328.3:
a) The termwaters of the United States means
1) All waters which are currently used, or were used in the past, or may be susceptible to use in interstate orforeign 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,potholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which couldaffect interstate or foreign commerce including any 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 Sates under the definition;
5) Tributaries of waters identified in paragraphs (a) (1) through (4) of this section;
6) The territorial seas;
7) Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in paragraphs (a)(1) through (6) of this section….
b) The term wetlands means those areas that are inundated or saturated by surface or ground water at a frequencyand duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetationtypically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, andsimilar areas.
c) The term adjacent means bordering, contiguous, or neighboring. Wetlands separated from other waters of theUnited States by man-made dikes or barriers, natural river berms, beach dunes and the like are “adjacentwetlands.”
Army Corps of Engineers (ACOE) jurisdiction in non-tidal waters typically extends to the ordinary high
water mark (OHWM). The OHWM for intermittent streams, for example, can be determined by “the
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Impact Sciences, Inc. 5 Hidden Creeks Estates860.001 May 2007
fluctuations of water as indicated by physical characteristics such as clear, natural lines impressed on the
bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter
and debris, or other appropriate means that consider the characteristics of the surrounding areas” (33
CFR 328.3(e)). In arid areas of the southwest, the OHWM may occur at a lower level than where the
typical physical indicators are present, due to unusually high flows, not occurring on a typical annual
cycle. (Allen, et al., 2001)
In 1976, ACOE and the Environmental Protection Agency (EPA) adopted a regulatory definition, which
states that wetlands are:
Those areas that are inundated or saturated by surface or ground water at a frequency andduration sufficient to support, and that under normal circumstances do support, a prevalence ofvegetation typically adapted for life in saturated soil conditions. Wetlands generally includeswamps, marshes, bogs, and similar areas. (33 CFR 328.3(b))
In 1987, the ACOE published the Corps of Engineers Wetland Delineation Manual (1987 Manual) which is
used to determine the extent of its jurisdiction in wetlands. Subsequently, additional guidance
documents have been issued by the ACOE, which further clarify the use of the 1987 Manual.
The U.S. Supreme Court, in a 2001 opinion, found that wetlands and waters that are isolated from
navigable waters, should not be considered jurisdictional “waters of the United States” if the basis for
jurisdiction is use of the waters by migratory birds. The Court held that use by migratory birds did not
constitute sufficient reason to regulate these wetlands. However, if waters can be shown to have other
uses that constitute sufficient interstate commerce use, then they might constitute “waters of the United
States.” This determination shall be made independently of procedures described in the 1987 Manual.
The U.S. Supreme Court decision was made based on the jurisdiction of the waters and not on the
methods used to delineate waters. A site-specific evaluation of the ACOE’s jurisdiction is generally
required, although many site-specific decisions have already been made for various water bodies. These
decisions are regularly published on the ACOE District’s website.
If determined to be jurisdictional “waters of the United States” by the ACOE, most impacts to such areas
require approval under the authority of the Clean Water Act and its implementing regulations.
Section 404 Permits
The deposition of fill to an area delineated as “waters of the United States,” including wetlands, and
determined to be under the ACOE jurisdiction, require a permit or other approval by the ACOE
Regulatory Branch. Fill is broadly defined to include most materials (rock, soil, pilings, concrete, wood,
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some incidental fallback of soil from earth-moving equipment, and in some cases additional water) that
might be discharged into a water or wetland.
Permitting requirements for a project vary depending on the nature and extent of project-related impacts
to jurisdictional resources. The ACOE issues individual and general permits, depending on the activity.
General permits may be “Nationwide,” “Statewide,” or “Regional” in scope. Both individual and general
permits require extensive review, as outlined in the Section 404(b)(1) guidelines. Both must be subject to
an alternatives analysis and public notice (and possibly public hearing), generally require mitigation, and
may be conditioned by both the ACOE district and by the state (under the state’s Section 401 certification
process). General permits are issued for categories of activities that are considered to have de minimus
impacts on the environment. General permits are typically issued to the ACOE with the provision that
applicants with projects that meet the permit conditions may be authorized to use the ACOE general
permit. According to the ACOE’s March 2000 nationwide permits (NWPs), if project impacts are greater
than 0.5 acre or impact greater than 300 linear-feet of a perennial streambed the project will not qualify
for coverage under the NWPs. All of the Nationwide Permits are due for reauthorization or revision in
2007.
Most Section 404 permits require mitigation for reducing overall impacts to net wetland area and
functions.
California Department of Fish and Game
The State of California regulates water resources under Sections 1600 to 1603 of the Fish and Game Code
of California. Section 1602 mandates that:
It is unlawful for any person to divert or obstruct the natural flow or substantially change the bed,channel, or bank of any river, stream, or lake designated by the department, or use any materialfrom the streambeds, without first notifying the department of that activity.
CDFG considers most natural drainages to be streambeds unless it can be demonstrated otherwise.
Streambeds are defined in the California State Register (Vol. 87, No. 9, Section 1.72) as follows:
A stream is a body of water that follows at least periodically or intermittently through a bed orchannel having banks and that support fish or other aquatic life. This includes watercourseshaving surface or subsurface flow that supports or has supported riparian vegetation.
CDFG jurisdiction includes ephemeral, intermittent, and perennial watercourses, and is often extended to
the limit of riparian habitats that are located contiguous to the water resource and that function as part of
the watercourse system. Section 2785(e) of the Fish and Game Code of California states, “Riparian habitat
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means lands which contain habitat which grows close to and which depends on soil moisture from a
nearby freshwater source.”
Streambed Alteration Agreements
Any project that impacts CDFG jurisdictional areas, including fills, vegetation removal, or bridging,
requires a Section 1602 Streambed Alteration Agreement from CDFG. Much of the information necessary
to apply for ACOE Section 404 permits (e.g., project description, potential impacts, and mitigation
measures) is required for the Streambed Alteration Agreement application.
Regional Water Quality Control Board)
Section 401 of the federal Clean Water Act authorizes the State of California to certify that federal permits
and licenses do not violate the state’s water quality standards. The state’s implementing regulations to
conduct certifications are codified under the California Code of Regulations Title 23 Waters, Sections 3830
through 3869. Projects qualifying for an ACOE Section 404 permit must submit materials for review to
the appropriate Regional Water Quality Control Board and request a Section 401 certification. Much of
the information necessary to apply for ACOE Section 404 and CDFG Section 1602 permits (e.g., project
description, potential impacts, and mitigation measures) is required for the Section 401 Certification.
METHODOLOGY
To evaluate the extent of ACOE and CDFG jurisdiction on the project site, a literature search and a
jurisdictional delineation were conducted by Impact Sciences. All available literature relevant to the
jurisdictional determination and describing biological, soil, and hydrologic resources within the vicinity
of the site was examined prior to the field study. The literature examined for this report includes:
Soil Survey of Los Angeles County, California, West San Fernando Valley Area (United StatesDepartment of Agriculture [USDA], Natural Resources Conservation Service, Web Soil Survey 1.1,National Cooperative Soil Survey, 4/24/2006);
U.S. Fish and Wildlife Service’s National Wetland Inventory Map (NWI), Oat Mountain Quadrangle;
USGS Oat Mountain Quadrangle;
The Jepson Manual: Higher Plants of California;
The ACOE District’s website to determine if a jurisdictional determination has been made on thespecific waterbody; and
National List of Plant Species that Occur in Wetlands, Region 0 – California.
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On January 17 through 20 and March 13 through 14, 2006, Impact Sciences biologists conducted field
delineations on the project site. The boundaries of all jurisdictional waters, including wetlands and
streambeds, and the extent of adjacent riparian vegetation were determined and mapped. Visual
observations of the OHWM, shoreline banks, and riparian vegetation were used to determine the extent
of ACOE and CDFG jurisdiction. Additionally, data documenting hydrology, soils, and vegetation were
collected at various sampling points.
GPSMapping
Jurisdictional boundaries were determined and mapped using resource-grade Trimble Global Positioning
System (GPS) Units with sub-meter accuracy. Where possible, “waters of the United States,” including
wetlands (as defined by the ACOE 1987 Manual) and stream corridors, were mapped utilizing the GPS
equipment. In areas with limited to no access, “waters of the United States” and CDFG streambeds/limits
of riparian vegetation were subsequently delineated using a combination of GPS mapping, aerial
photography, and on-site estimations of average streambed widths.
The jurisdictional areas calculated by Geographic Information Systems (GIS) during the analysis of the
delineation were mapped onto an ortho-aerial photograph.
SITE DESCRIPTION
The project site is located within the southern reaches of the Santa Susana Mountains near the western
edge of Los Angeles County. Existing uses within the project site boundaries consist of equestrian
facilities located in the southeastern part of the property, movie and television production facilities
located in the central-eastern part of the property, and cattle ranching facilities and associated access
roads located throughout the property.
Watershed
The proposed project site is located within the Bull Canyon sub-watershed, which is tributary to the Los
Angeles River Hydrological Unit, which itself is located within the South Coast Hydrologic Region. The
project site is located near drainage headwaters, where steep, erosional, generally south-draining faces
direct water toward the project site. The size of the watershed draining through the property is
approximately 2,250 acres (approximately 3.5 square miles).
Topography
Elevations within the Hidden Creeks Estates property range from approximately 2,145 feet above mean
sea level in the northernmost extent of the property to 1,350 feet in the southernmost, at the confluence of
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Impact Sciences, Inc. 9 Hidden Creeks Estates860.001 May 2007
Browns Canyon Wash and Mormon Canyon. Topography on the site ranges from rolling hills with
slopes of 5 percent or less to steep hillsides and highly eroded streambanks with maximum slopes in
excess of 60 percent. Erosional surfaces are the major landscape feature found throughout the property.
Steep hillsides, naturally erodable and unconsolidated soils, and the long-term impacts of cattle grazing
(such as loss of native vegetation, soil compaction, eroded streambanks, decreased rainwater infiltration
and increased overland surface flows) have all resulted in landscape features associated with high levels
of erosion. These features include slumped hillsides, a number of ephemeral washes, and the formation
of deeply eroded gullies with concomitant soil and vegetation loss.
Hydrology
Water is the driving force in creating and sustaining stream habitat and riparian vegetation. Apart from
the two primary channels of Mormon Canyon and Browns Canyon Wash, the dominant water sources for
the project site are surface and subsurface flows originating within the boundary of the project site.
Additional water sources include runoff from the Santa Susana Mountains to the north, most notably
within the Mormon Canyon and Browns Canyon Wash channels. In general, directional flows are
oriented to the south.
The project site can be divided into two distinct watersheds: Mormon Canyon to the east and Browns
Canyon Wash to the west (Figure 2a). On the eastern half, the project site contains the upper headwaters
of three tributaries to Mormon Canyon, as well as three segments of the mainstem of Mormon Canyon.
On the western half, the project site contains one tributary to Browns Canyon Wash and two segments of
the mainstem of Browns Canyon Wash. Additionally, the project site contains the confluence of the two
main streams where Mormon Canyon enters Browns Canyon Wash. The upstream reaches of both
Mormon Canyon and Browns Canyon Wash are located off the project site to the northeast and northwest
respectively.
The dominant hydrologic feature on the project site is gently to steeply eroded ephemeral washes
tributary to the two primary channels. In general, erosional forces within the tributaries steadily increase
moving downstream, and then decrease prior to entering the main channels. Both Browns Canyon Wash
and Mormon Canyon flow through steep-walled canyons upstream and north of their convergence at the
southernmost edge of the project site. Other hydrologic features on the project site include a limited
number of flat and depressed areas that contain vegetative and hydrologic characteristics associated with
both seasonal and permanent wetlands.
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Impact Sciences, Inc. 10 Hidden Creeks Estates860.001 May 2007
Soils
Soils within the property boundary (Table 1, On-Site Soils Associated with Waters and Streambeds and
their Hydrological Characteristics), as mapped by the Natural Resources Conservation Service (NRCS),
are Balcom and Gazos series silty clay loam with slopes between 15 and 50 percent. Additionally, a small
distribution of Lopez series shaley clay loam with slopes of 30 to 50 percent exists outside the propertyboundary, but within an area of interest.
Table 1On-Site Soils Associated with Waters and Streambeds and their Hydrological Characteristics
Mapped SoilSoil Characteristics
Descriptive terms are defined in SCS soil surveys.Hydric(NRCS)
BalcomWell drainedLow to high runoffModerate to moderately slow permeability
Non-hydric
GazosWell drainedHigh to very high runoffModerately slow permeability
Non-hydric
LopezSomewhat excessively drainageRapid to very rapid runoffModerate permeability
Non-hydric
Vegetation
A combination of topography, hydrology, and land use strongly dictates the extent and types of
vegetative communities found on the project site; specifically, vegetative types are largely determined by
relative slope, the location of surface and subsurface flows, and the presence or absence of cattle grazing.
A total of 15 plant communities were identified on the project site, including:
Mixed Willow Riparian Woodland,MixedCoast Live Oak-Willow Riparian Woodland,Mulefat Scrub,Mixed Mulefat-Bulrush/Cattail-Rush Wetland,Mulefat Scrub-Non-Native Grassland,Non-Native Grassland,Coast Live Oak Woodland,Mixed California Black Walnut-Coast Live Oak Woodland,California Walnut Woodland,Mixed Sage Scrub,Coastal Sage Chaparral Scrub,California Sagebrush Scrub,Chamise Chaparral,Tamarisk Scrub, andDisturbed
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Upland Vegetation
The vast majority of the project site is comprised of upland vegetative communities. In general, on-site
upland vegetation can be divided into two categories: vegetation readily accessed by cattle and thus
impacted by grazing, and inaccessible vegetation that exhibits little to no grazing impacts. Areas heavily
grazed include easily accessed, gentle- to medium-sloped hillsides, ridges, and plateaus. Non-native
annual grasses dominate these areas. Areas marginally impacted by grazing include dry, steep hillsides
in which sparse groundcover and the lack of regular grazing allow native vegetation to persist. In
general, non-native grasslands/disturbed mixed sage scrub generally comprises these areas. Upland
areas not impacted by grazing include remote canyons and ravines with especially steep slopes in which
native vegetation was never supplanted by introduced grasses. These areas include mixed sage scrub,
coastal sage-chaparral scrub, and chamise chaparral vegetation communities.
Riparian and Wetland Vegetation
Of the 15 plant communities identified above, mixed willow riparian woodland, mixed coast live oak-
willow riparian woodland, mulefat scrub, mixed mulefat-bulrush/cattail-rush wetland, coast live oak
woodland, mixed California black walnut-coast live oak woodland, and California walnut woodland are
associated with on-site stream channels and riparian corridors. The locations, characteristics, and extents
of these plant communities within the Hidden Creeks Estates project site are discussed in detail in the
following sections.
Functional Assessment of Jurisdictional Streams and Wetlands
All open space performs various and multiple ecological functions. The degree to which functions are
performed depends on both physical (e.g., location, size, soils, and available moisture) and biological
characteristics (e.g., species dominance, composition, diversity, and spacing). Examples of ecological
functions performed by ACOE and CDFG jurisdictional aquatic resources include wildlife habitat,
biofiltration, groundwater recharge, stormwater attenuation, shoreline or streambank stabilization, and
sediment movement or trapping.
While functions may be performed with varying effectiveness, the values of any given stream/riparian
corridor are related to the degree to which functions are performed and their relationship to the resources
which are of concern to local, regional, state, and national interests.
The water resources on the Hidden Creeks Estates project site vary considerably in the degree to which
functions are performed. General ecological functions associated with the project site are described
below in Table 2, Ecological Functions Associated with Stream and Wetlands on Hidden Creeks
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Estates Project Site. A more-detailed functional assessment for specific sites within the proposed project
boundary appears in Table 3, Summary of Waters, Wetlands, and Riparian Corridors within the
Property Boundaries of the Hidden Creek Estates Project Site, in the Discussion of Findings section.
Table 2Ecological Functions Associated with Stream and Wetlands on Hidden Creeks Estates Project Site
Function Performance – Qualitative Ratings of Opportunity and EffectivenessWildlife Habitat Characteristics of high functions and values associated with wildlife habitat are areas of
adequate size, buffers from disturbances, shelter, minimum of disturbances, availabilityof food plants and water, and ability to move to other habitat areas. The HiddenCreeks Estates site exhibits all of these characteristics.
Biofiltration/NutrientRetention or Cycling
The riparian vegetation along the creeks absorbs nitrates from livestock waste andrunning water absorbs oxygen, necessary to decrease otherwise high levels ofbiological oxygen demand (BOD). Both of these factors aid in denitrification and thebreakdown of organic wastes from cattle and wildlife. These functions are high alongBrowns and Mormon Canyons, and to a lesser extent along the center drainage.
ShorelineStabilization/SedimentRetention
Shoreline stabilization occurs where sufficient vegetation is present along streamcorridors to control streambank erosion. In those areas easily accessed by cattle,shoreline stability is minimal due to the lack of streambank vegetation, as well as theslumping of banks resulting from trampling. Most of the sparsely vegetatedstreambanks are eroding and contribute to the quantity of sediment movingdownstream, leading to a low-value determination for these areas.
Stormwater Attenuation Stormwater attenuation in the system is affected by widespread soil compaction andthe gradient (slope) that exists throughout the project site. The greatest potential forstormwater attenuation is found along the mainstem of Browns Canyon Wash, where astormwater/sediment retention dam is located just off the project site, the uppertributary to Mormon Canyon, and the mainstem of Mormon Canyon, the uppertributary to Browns Canyon Wash.
Groundwater Recharge Although subsurface flows (baseflow) constitute an important component of the site’shydrology, there are no major groundwater resources within the boundaries of theproject site, which is characterized by medium to high slopes. Subsequently, potentialrecharge of onsite groundwater resources will not be discussed further.
DISCUSSION OF FINDINGS
ACOE Waters of the United States and Wetland Areas (Section 404, Clean Water Act)and CDFG Streambeds (Sections 1600–1603, Fish and Game Code of California)
The project site contains the upper headwaters of three tributaries to Mormon Canyon, three segments of
the Mormon Canyon mainstem, one tributary to Browns Canyon Wash, and two segments of the Browns
Canyon Wash mainstem. All stream channels on the project site are classified as riverine by the
hydrogeomorphic (HGM) system, which is a functional assessment methodology (Brinson, 1993). The
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Impact Sciences, Inc. 13 Hidden Creeks Estates860.001 May 2007
two mainstems are classified as riverine, perennial streambeds by the Cowardin classification system
(Cowardin, 1979), while the tributaries are classified as riverine, intermittent.
Assuming an OHWM and an extant hydrologic connection with a definable “navigable waters of the
United States,” these stream channels fall under the jurisdiction of the ACOE. Since all waters on the
project site eventually flow to Browns Canyon Wash, a tributary to the Los Angeles River (defined as
“navigable waters of the United States”), all stream channels within the project site meet the jurisdictional
definition of “waters of the United States,” pursuant to Section 404 of the Clean Water Act. Additionally,
two separate areas, one located within the project site boundary and one located off site, potentially meet
the definition of “wetlands adjacent to waters (other than waters that are themselves wetlands).”
CDFG riparian corridors include the streambed and channel, extending to the top of the bank, at a
minimum, and to the outward extent of the outer edge of the canopy of riparian vegetation, if a canopy is
present. All streams and riparian vegetation on the project site are regulated by CDFG.
The delineation of ACOE and CDFG jurisdictional areas is shown in Figure 2a and detailed throughout
Figures 2b through 2f, below.
Individual stream reaches within the property boundaries of the Hidden Creeks Estates project site are
summarized in Table 3, Summary of Waters, Wetlands, and Riparian Corridors within the Property
Boundaries of the Hidden Creek Estates Project Site, and Table 4, Summary of Jurisdictional Areas
(acres) – Hidden Creeks Development Project Site. Vegetative communities, functional assessments,
and jurisdictional areas are given for each reach.
OFF-SITE RESOURCES
Off-site jurisdictional resources located outside of the upper eastern border of the project site (Figure 2f
and Site Photos in Appendix A) that have the potential to be impacted by the construction of an access
road (continuation of Mason Ave.) include:
Upper reaches of the on-site stream segments described earlier in Table 3 as “Upper tributary toMormon Canyon; Mormon Canyon mainstem segments;”
An approximately 0.33-acre site that potentially meets the definition ACOE “wetlands adjacent towaters.” This is described as a mixed mulefat-bulrush/cattail-rush wetland. A more detaileddescription of this location can be found in Appendix B, Wetland Determination Data Form B titled“Off-Channel Mormon Canyon Headwater;” and
CDFG
ACOE WetlandACOE
Boundary
Legend:
Mor
mon
Can
yon
Browns Canyon Wash
Figure 2b
Figure 2c
Figure 2e
Figure 2f
Mason Avenue (Proposed)
Figure 2d
Legend:
Project Boundary
Figure Index Location
Approximate Hidden Creeks Drainage Location
Hidden Creeks – Drainage Detail
FIGURE2b
860-001•07/06
SOURCE: Impact Sciences, Inc. – July 2006
APPROXIMATE SCALE IN FEET
500 250 0 500
n
CDFG
ACOE WetlandACOE
Boundary
Legend:
Mor
mon
Can
yon
Browns Canyon Wash
Figure 2b
Figure 2c
Figure 2e
Figure 2fM
ason Avenue (Proposed)Figure 2d
Legend:
Project Boundary
Figure Index Location
Approximate Hidden Creeks Drainage Location
Hidden Creeks – Drainage Detail
FIGURE2c
860-001•07/06
SOURCE: Impact Sciences, Inc. – July 2006
APPROXIMATE SCALE IN FEET
500 250 0 500
n
CDFG
ACOE WetlandACOE
Boundary
Legend:
Mor
mon
Can
yon
Browns Canyon Wash
Figure 2b
Figure 2c
Figure 2e
Figure 2fM
ason Avenue (Proposed)Figure 2d
Legend:
Project Boundary
Figure Index Location
Approximate Hidden Creeks Drainage Location
Hidden Creeks – Drainage Detail
FIGURE2d
860-001•07/06
SOURCE: Impact Sciences, Inc. – July 2006
APPROXIMATE SCALE IN FEET
500 250 0 500
n
CDFG
ACOE WetlandACOE
Boundary
Legend:
Mor
mon
Can
yon
Browns Canyon Wash
Figure 2b
Figure 2c
Figure 2e
Figure 2f
Mason Avenue (Proposed)
Figure 2d
Legend:
Project Boundary
Figure Index Location
Approximate Hidden Creeks Drainage Location
Hidden Creeks – Drainage Detail
FIGURE2e
860-001•07/06
SOURCE: Impact Sciences, Inc. – July 2006
APPROXIMATE SCALE IN FEET
500 250 0 500
n
CDFG
ACOE WetlandACOE
Boundary
Legend:
Mason Avenue (Proposed)
Mor
mon
Can
yon
Browns Canyon Wash
Figure 2b
Figure 2c
Figure 2e
Figure 2f
Mason Avenue (Proposed)
Figure 2d
Mason Avenue (Proposed)
Legend:
Project Boundary
Figure Index Location
Approximate Hidden Creeks Drainage Location
Hidden Creeks – Drainage Detail
FIGURE2f
860-001•07/06
SOURCE: Impact Sciences, Inc. – July 2006
APPROXIMATE SCALE IN FEET
500 250 0 500
n
Jurisdictional Delineation
Impact Sciences, Inc. 19 Hidden Creeks Estates860.001 May 2007
Table 3Summary of Waters, Wetlands, and Riparian Corridors within the Property Boundaries of the Hidden Creek Estates Project Site
Functional Assessments
Figure Stream Reach Vegetative Communities and General DescriptionWildlifeHabitat
Biofiltration/Nutrient
Retention orCycling
ShorelineStabilization/SedimentRetention
StormwaterAttenuation
Headwaters ofupper tributary toMormon Canyon
California walnut woodland (i.e., southernCalifornia black walnut [Juglans californica], coastlive oak [Quercus agrifolia]) dominant throughoutreach; dense understory (i.e., mulefat [Baccharissalicifolia], poison oak [Toxicodendron diversilobum])in upper reaches, relatively open canopydownstream; minimal to no impacts from cattlegrazing; coastal sage-chaparral scrub buffercommunity (i.e., toyon [Heteromeles arbutifolia],ceanothus [Ceanothus sp.], scrub oak [Quercusdumosa], California sagebrush [Artemisia californica])
High;considerableusage bywildlife
High; denseriparian andbankvegetation
High; mature,undisturbedvegetation;westernheadwatersusceptible toerosion fromroad cut
High; densecanopy, thickunderstory,and infiltrationcapacity ofpredominantlysandy soils
2b
Upper tributary toMormon Canyon;Mormon Canyonmainstem segments
Coast live oak woodland in upper reach; steeplyeroded and sparsely vegetated ravine; off-channelmulefat scrub (see Photo 1); mixedwillow riparianwoodland (i.e., western sycamore [Platanusracemosa], willow [Salix sp.]) at mainstem;understory includes California blackberry (Rubusursinus); see Photo 2; mainstem not accessed bycattle; this reach also contains small CDFG riparianarea off mainstem heavily impacted by grazing
Medium inupper reaches;high nearmainstem
Medium; lackof bankvegetation inupper reach
Low in upperreaches due tograzingimpacts; highnear and atmainstem
Medium foroverall reach;erosion andlack of bankvegetation
2c
Middle tributary toMormon Canyon
Headwaters of this reach highly impacted bygrazing and adjacent movie production facilitiesand lack riparian canopy and bank vegetation;highly erodable ephemeral wash leads to steep,incised ravine; coast live oak woodland in middlereach eventually leads to mixedwillow riparianwoodland nearing mainstem
Low in upperreaches;medium tohigh in lowerreach
Low in upperreaches due tograzing;medium tohigh in lowerreach
Low in upperreaches due tograzingimpacts;medium inlower reach
Low in upperreaches due tocompactedsoils and higherosion;medium inlower reach
Jurisdictional Delineation
Impact Sciences, Inc. 20 Hidden Creeks Estates860.001 May 2007
Functional Assessments
Figure Stream Reach Vegetative Communities and General DescriptionWildlifeHabitat
Biofiltration/Nutrient
Retention orCycling
ShorelineStabilization/SedimentRetention
StormwaterAttenuation
Headwaters oflower tributary toMormon Canyon(Center Drainage)
Headwaters of this reach highly erosional; impactsfrom grazing and road cut (see Photo 3); lack ofbank vegetation and riparian canopy; lower reachwithin ravine also highly erosional and lackscanopy; bank and buffer vegetation primarilyconsists of disturbed mixed sage scrub (i.e., non-native grasses mixed with black sage [Salviamellifera], toyon, California sagebrush); mulefatwithin stream channel
Low; lack ofripariancanopy andbankvegetation
Low; highlyeroded andlackingriparianvegetation
Low;ephemeralwash in upperreach highlysusceptible toerosion
Low due toimpacts fromgrazing,roadcuts,productionfacilities
Lower tributary toMormon Canyon(Center Drainage)
California walnut woodland in upper reach, coastlive oak woodland in lower reach with densecanopy; understory includes toyon; area notdirectly impacted or accessed by cattle
Medium;dense canopy;considerableunderstory
Medium;impacted byupstreamareas
Medium;impacted byupstreamareas
Medium2c (cont’d)
Mormon Canyonmainstem segment
Mixed willow riparian woodland; dense canopyand thick understory; moderately disturbed areawith one concrete road crossing; mature stands ofcoast live oak within upper riparian zone
High; maturetrees andcomplexunderstoryvegetation
High; denseriparian andbankvegetation
High; matureriparian treesand densevegetation
High; presenceof spreadingzones anddensevegetation
Westernheadwaters oftributary to BrownsCanyon Wash
Headwaters of this reach undisturbed and notimpacted by grazing; high-sloped ravines withmoderate to high levels of erosion; narrow riparianzone with sage scrub (i.e., mulefat mixed withpoison oak, laurel sumac [Malosma laurina],monkeyflower [Mimulus aurantiacus], lemonadeberry [Rhus integrifolia], toyon; coast live oakcanopy in lower reaches)
High;undisturbedarea with richplant diversity
High; denseriparian andbankvegetation
Medium; areais highlyerosional
Medium; highslopes andnarrowcanyons
2d
Tributary (upperreach) to BrownsCanyon Wash
Entire reach impacted by cattle; coast live oakcanopy with general lack of understory; non-nativegrassland buffer community west of drainage;grassland/mixed sage scrub buffer communitypredominant east of drainage
Medium dueto grazingimpacts
Medium;general lack ofbankvegetation andcomplexunderstory
Low due tograzingimpacts
Mediumthroughoutreach
Jurisdictional Delineation
Impact Sciences, Inc. 21 Hidden Creeks Estates860.001 May 2007
Functional Assessments
Figure Stream Reach Vegetative Communities and General DescriptionWildlifeHabitat
Biofiltration/Nutrient
Retention orCycling
ShorelineStabilization/SedimentRetention
StormwaterAttenuation
Tributary (middlereach) to BrownsCanyon Wash
Reach includes potential off-channel wetland(mulefat, rush [Juncus sp.], bulrush [Scirpus sp.])highly impacted by grazing (see Photo 4;mixedwillow riparian woodland in tributary channel withmature sycamore, cottonwood [Populus fremontii],and willow)
High invicinity ofmixed riparianwoodland andwetland
High; complexand denseunderstory;presence ofwetlandcommunity
High; densebankvegetation
High; presenceof areas withpotential forincreasedhydro-period
2d (cont’d) Eastern headwatersof tributary toBrowns CanyonWash
Headwaters of this reach highly eroded ephemeralwashes; impacts from grazing and road cut;streambed vegetation dominated by mulefat andlack of bank vegetation; non-nativegrassland/disturbed sage scrub buffer community;oak canopy in lower reach with minimal bankvegetation (see Photo 5) and high erosion
Low; highlyerosionalephemeralwashes withminimalvegetation
Low; lack ofbank andriparianvegetation
Low; highlyerosional dueto grazingimpacts androad cut
Low
Tributary (lowerreach) to BrownsCanyon Wash
Coast live oak woodland community; large,contiguous riparian canopy; non-native grasslandcommunity buffer community along eastern side ofchannel; non-native grassland/disturbed sage scrubbuffer community along western side
Medium dueto grazingimpacts
Medium; lackof complexunderstory
Medium;minimal bankvegetation
Medium
Browns CanyonWash uppermainstem segment
Reach impacted by road along western bank; lowerreach impacted by off-site, downstreamsediment/flood control dam (Photo 6) and large on-site road cut (Photo 7); stream primarily erosionalwith transition to depositional at road cut (roughly450 feet upstream of dam); mixed willow riparianwoodland in lower reach; dense but narrowriparian zone with mixed sage-scrub buffercommunity in upper reach; large stand of mulefatscrub upstream of dam within depositional area
High; dense,complexunderstory;moderatecanopy; noimpacts fromgrazing; highplant diversity
High; densebankvegetation
Medium;segments ofreach erosional
High;downstreamsediment/flood controldam createslargedepositionalarea
2e
Browns CanyonWash lowermainstem segment
Low gradient; channel between road on westernbank and small developed area on eastern bank;coast live oak woodland; sparse understory
Medium;disturbed areadue to roadand adjacentdevelopment
Medium;sparseunderstory
Medium; reachlacks sedimentdue toupstream dam
Medium
2f Off-site resources N/A N/A N/A N/A N/A
Jurisdictional Delineation
Impact Sciences, Inc. 22 Hidden Creeks Estates860.001 May 2007
Table 4Summary of Jurisdictional Areas (acres)Hidden creeks Development Project Site
DrainageACOEWatersAvg. Width/Area ACOEWetlands
CDFG StreambedsAvg. Width/Area
Mormon Canyon mainstemsegment
14 feet/0.6 0.00 4.25*
Upper tributary to MormonCanyon
5 feet/0.4 0.00 5.8*
Middle tributary to MormonCanyon
10 feet/0.4 0.00 1.75*
Center Drainage 5 feet/0.17 0.00 3.5*Browns Canyon Wash 10 feet/0.35 0.00 2.5*Main tributary to Browns CanyonWash
8 feet/1.35 0.32 9.71*
Total (acres) 3.38 0.32 27.51Off site 0.31 0.33 4.65
*Acreage calculation based on habitat polygon area, not channel width.
Two channels tributary to Browns Canyon after passing through a neighboring residentialdevelopment, presently under construction. One of these channels comprises ACOE and CDFGresources and, aside from some mulefat and mugwort, both channels are vegetated primarily withcoastal sage chaparral scrub and mixed sage scrub plant species.
SUMMARY OF JURISDICTIONAL RESOURCES
This jurisdictional delineation report documents the extent of “waters of the United States,” including
wetlands under federal jurisdiction and streambeds under CDFG jurisdiction on the Hidden Creeks
Estates project site. Based on field studies employing sub-meter GPS equipment and observations from
aerial photography (field verified), within the Hidden Creeks project boundary the total area of “waters
of the United States” under ACOE jurisdiction is 3.38 acres, and wetlands under ACOE jurisdiction is 0.32
acre. Streambeds and riparian corridors under the jurisdiction of the CDFG total 27.51 acres.
Outside the project boundary, but within 300 feet of the proposed access road, are found 0.31 acre of
ACOE “waters of the United States,” 0.33 acre of ACOE wetlands, and 4.65 acres of CDFG streambeds.
Impact Sciences recommends concurrence with this delineation be obtained from the ACOE and CDFG
prior to commencement of any development planning activity. If ACOE and/or CDFG do take
jurisdictionof any on-site waters/streambeds, a determination of the extent of jurisdiction impacts may be
Jurisdictional Delineation
Impact Sciences, Inc. 23 Hidden Creeks Estates860.001 May 2007
determined by overlaying the development plans on an aerial map at that time. Activities that impact
delineated areas may need permits, with mitigation required as conditions of those permits.
Coordination between Impact Sciences and the site planners is essential to ensure that regulatory and
procedural changes have not occurred subsequent to anticipated agency concurrence with this report.
REFERENCES
CaliforniaDepartment of Fish and Game. 2005. Fish and Game Code of California.
Code of Federal RegulationsVol. 33 Part 200 to End. July 2000. U.S. Government Printing Office.
Cowardin, L. M., et al. 1979. “Classification of wetlands and deepwater habitats of the United States.”U.S. Fish and Wildlife Service. Washington, D.C.
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. “Technical ReportY-87-1.” U.S. Army Engineer Waterways Experiment Station. Vicksburg, MS.
Hickman, James C. 1993. The Jepson Manual: Higher Plants of California. University of California Press,Berkeley, CA.
U.S. Department of Agriculture, Natural Resources Conservation Service. April 14, 2006. Soil Survey ofLos Angeles County, California, West San Fernando Valley Area, Web Soil Survey 1.1, NationalCooperative Soil Survey.
APPENDIX ASite Photos
Mor
mon
Can
yon
Browns Canyon Wash
Mason Avenue (Proposed)
Legend:
Project Boundary
Approximate Hidden Creeks Drainage Location
Photo Location and Direction
OS3
OS2
1
3
X
7
5
6
4
2
OS1
Hidden Creeks – On-Site and Off-Site Photo Locations
APPENDIXA
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NOT TO SCALEn
Photo 1 Photo 2 Photo 3
Photo 5 Photo 6 Photo 7
Photo 4
Hidden Creeks – On-Site Photos
APPENDIXA
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OS1
OS2
OS3
Hidden Creeks – Off-Site Photos
APPENDIXA
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APPENDIX BData Sheets
STREAM DATA FORM GPS Data taken: Yes No –Western drainageProject / Site: Hidden Creeks Sample Plot # Browns Cyn Wash (Blue line)Owner/Developer: Field Date: 1/20/06Normal Circumstances? No – major flood control structure Lat./Long.:Tributary to: Los Angeles River County: L.A.Adjacent land use: equestrian, upstream park -near pristine State: California
VEGETATION: Buffer Community Type:Riparian Tree Species, % Cover Mature? Riparian/Hydrophytic Herb. Species % Cover X=Native
Populus fremontii Poison oakSalix Yes Yerba santaPlatanus racemosa Yes A. californicaJ. californica ToyonOaks, Specify: Coast Live Yes
Riparian Sapling / Shrub SpeciesMulefat (large stand at dam)Umbrella sedgeWater cress
Comments: high quality conditions
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4”4-8”8-12”12-16Boulders Bedrock ”Gravel or Cobble Sand or Sandy loam Muck, Silt Clay or LoamComments: some erosion and incision
HYDROLOGY Source of Water: Spring/Seep ; Urban/Agricultural Runoff ; Can’t Determine ; OtherMaximum Depth of inundation: in. Spring – groundwater discharge and surface runoffDepth to Water Standing in Pit: >16 in. Permanent flows Intermittent flows Temporary flowsDepth to Saturated Soil: >16 in. Steep Gradient Moderate Gradient Low Gradient
Indicators:Buffer width; Ave. Width Ft. DitchedChannel Banks or OHWM present:
Yes No Buffer Continuous for length Graded –Detention basinGroundwater Recharge? Yes at dam; NoComments: High quality habitat
Hydrology altered by detention basin formed by large stacked concrete dam
STREAM CHARACTERISTICS
Stream Width Average: 10 Feet Recent Erosion Evident Yes; NoStream Length (field or map calculation: 1384 Feet
Watershed Area: 3.5 Square MilesComments: good habitat and pooling over entire reach
Determined By: Brody/Ferry Impact Sciences, Inc.
STREAM DATA FORM GPS Data taken: Yes No (ACOE centerline)Project / Site: Hidden Creeks Sample Plot # Main Trib to Brown’s Cyn (blue line)Owner/Developer: Forestar Real Estate Group Field Date: 1/19/06Normal Circumstances? Yes Lat./Long.:Tributary to: Browns Canyon Wash County: L.A.Adjacent land use: Cattle grazing State: California
VEGETATION: Buffer Community Type:Riparian Tree Species, % Cover Mature? Riparian/Hydrophytic Herb. Species % Cover X=Native
Populus fremontiiSalix (lower reach) YPlatanus racemosa (lower reach YCottonwood 1 YOaks, Specify: Coast Live 70 Y
Riparian Sapling / Shrub SpeciesMulefat – isolated stands assoc. w/
wetland seep (lower reach)
Bulrush & Willows – coarse thicket
Comments: upper reaches – all sage scrub community – yerba buena to mulefat (channel + 5 ft buffer)Lower reaches – oak, mulefat
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4”4-8”8-12”12-16Boulders Bedrock ”Gravel or Cobble Sand or Sandy loam Muck, Silt Clay or LoamComments: Stream substrate mostly sand, but sandy loam in lower reaches.
HYDROLOGY Source of Water: Spring/Seep ; Urban/Agricultural Runoff ; Can’t Determine ; OtherMaximum Depth of inundation: in. Light flow in lower reaches; temp.- rain eventsDepth to Water Standing in Pit: >16 in. Permanent flows Intermittent flows Temporary flowsDepth to Saturated Soil: >16 in. Steep Gradient Moderate Gradient Low Gradient
Indicators:Buffer width; Ave. Width 3 Ft. DitchedChannel Banks or OHWM present:
Yes No Buffer Continuous for length Graded – road crossingsGroundwater Recharge? Yes ; NoComments: Leads to dam; ends at mulefat thicket (depositional area)
STREAM CHARACTERISTICS
Stream Width Average: 8 Feet ACOE Recent Erosion Evident Yes; NoStream Length (field or map calculation): 7300 Feet
Watershed Area: Project = 3.5 Square MilesComments: Impaired with multiple road crossings.
Determined By: RC Brody/Mike Ferry Impact Sciences, Inc.
STREAM DATA FORM GPS Data taken: Yes No –No BluelineProject / Site: Hidden Creeks Sample Plot # Center DrainageOwner/Developer: Field Date: 1/17/06Normal Circumstances? No – ranched and grazed Lat./Long.:Tributary to: Mormon Canyon (no blue line) County: L.A.Adjacent land use: ranching/farming/equestrian State: California
VEGETATION: Buffer Community Type:Riparian Tree Species, % Cover Mature? Riparian/Hydrophytic Herb. Species % Cover X=Native
Populus fremontii ToyonSalix Yerba buenaPlatanus racemosa Black sageJ. californica Upper reach Yes Non-native grasses 40-50 %Oaks, Specify: Coast Live, scrub yes (introduced annual)
Riparian Sapling / Shrub Species SumacMulefat Arundo in places (stream bottom)Juglans californica – upper reach
Bulrush & Willows – coarse thicket
Comments: riparian buffer sparse in upper reachOak woodland in lower reach
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4”4-8”8-12”12-16Boulders Bedrock ”Gravel or Cobble Sand or Sandy loam Muck, Silt Clay or LoamComments: mostly sand, but sandy loam in lower reaches only
HYDROLOGY Source of Water: Spring/Seep ; Urban/Agricultural Runoff ; Can’t Determine ; OtherMaximum Depth of inundation: in.Depth to Water Standing in Pit: >16 in. Permanent flows Intermittent flows Temporary flowsDepth to Saturated Soil: >16 in. Steep Gradient Moderate Gradient Low Gradient
Indicators:Buffer width; Ave. Width Ft. DitchedChannel Banks or OHWM present:
Yes No Buffer Continuous for length GradedGroundwater Recharge? Yes ; NoComments: impaired from grazing/ road cuts/ grading
Multiple culvert inputs from road w/ related erosion
STREAM CHARACTERISTICS
Stream Width Average: 4 Feet ACOE Recent Erosion Evident Yes; NoStream Length (field or map calculation: ACOE 2115 Feet
CDFG 3031Watershed Area: 3.5 Square MilesComments: ephemeral – dry wash
Impaired w/ fill in upper reachesHealthy oak woodland in lower reaches
Determined By: Brody/Ferry Impact Sciences, Inc.
STREAM DATA FORM GPS Data taken: Yes NoProject / Site: Hidden Creeks Sample Plot # Mormon Canyon (blue line)Owner/Developer: Forestar Real Estate Group Field Date: 1/18/06Normal Circumstances? Yes Lat./Long.:Tributary to: Browns Canyon Wash County: L.A.Adjacent land use: Some equestrian, 30 % grazed (to west) State: California
VEGETATION: Buffer Community Type:Riparian Tree Species, % Cover Mature? Riparian/Hydrophytic Herb. Species % Cover X=Native
Populus fremontii Sparse Y UplandSalix Large stand Y Coast sagebrush 40 %Platanus racemosa Sparse Y Black sageJuglans californica Sparse Y ToyonOaks, Specify: Coast Live 30% Y Laurel sumac
Riparian Sapling / Shrub SpeciesMulefat – isolated stands Y
- cattail Non-native grass 40%
Bulrush & Willows – large thicket
Comments:
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4”4-8”8-12”12-16Boulders Bedrock ”Gravel or Cobble Sand or Sandy loam Muck, Silt Clay or LoamComments:
HYDROLOGY Source of Water: Spring/Seep ; Urban/Agricultural Runoff ; Can’t Determine ; OtherMaximum Depth of inundation: in. Base flow and direct rainfallDepth to Water Standing in Pit: >16 in. Permanent flows Intermittent flows Temporary flowsDepth to Saturated Soil: >16 in. Steep Gradient Moderate Gradient Low Gradient
Indicators:Buffer width; Ave. Width Ft. DitchedChannel Banks or OHWM present:
Yes No Buffer Continuous for length GradedGroundwater Recharge? Yes ; No Multiple trail and road crossingsComments: Possibly perennial with some pooling and wetlands
STREAM CHARACTERISTICS
Stream Width Average: ACOE 9 Feet Recent Erosion Evident Yes; NoStream Length (field or map calculation: 1855 Feet
Watershed Area: Project = 3.5 Square MilesComments: Unimpaired – near natural state
Some incision – possibly due to upstream grazingHeadwaters: sulfur in stream
Determined By: Brody/Ferry Impact Sciences, Inc.
STREAM DATA FORM GPS Data taken: Yes NoProject / Site: Hidden Creeks Sample Plot # Main upper tribs to Mormon CynOwner/Developer: Field Date: 3/13/06Normal Circumstances? Yes, but grazed Lat./Long.:Tributary to: Mormon Canyon County: L.A.Adjacent land use: State: California
VEGETATION: Buffer Community Type:Riparian Tree Species, % Cover Mature? Riparian/Hydrophytic Herb. Species % Cover X=Native
Populus fremontii ChaparralSalix -toyonPlatanus racemosa -ceanothusJuglans -scrub oakOaks, Specify: Valley -Coastal sagebrush
Riparian Sapling / Shrub SpeciesWalnut/Mulefat riparian corridor 50%Coast Live Oak canopy 90%
Comments: More chaparral in streambed upstream, closer to Mormon Cyn becomes more riparian
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4”4-8”8-12”12-16Boulders Bedrock ”Gravel or Cobble Sand or Sandy loam Muck, Silt Clay or LoamComments: some erosion and incision, rocky substrate
HYDROLOGY Source of Water: Spring/Seep ; Urban/Agricultural Runoff ; Can’t Determine ; OtherMaximum Depth of inundation: in. Source: Other, natural surface runoffDepth to Water Standing in Pit: >16 in. Permanent flows Intermittent flows Temporary flowsDepth to Saturated Soil: >16 in. Steep Gradient Moderate Gradient Low Gradient
Indicators:Buffer width; Ave. Width 15 Ft. DitchedChannel Banks or OHWM present:
Yes No Buffer Continuous for length GradedGroundwater Recharge? Yes ; NoComments:
STREAM CHARACTERISTICS
Stream Width Average: 5 feet ACOE Recent Erosion Evident Yes; NoStream Length (field or map calculation): 2960 Feet Erosion: fill at road crossing
Watershed Area: 3.5 Square MilesComments: Dry oak-lined washDetermined By: R.C. Brody Impact Sciences, Inc.
STREAM DATA FORM GPS Data taken: Yes NoProject / Site: Hidden Creeks Sample Plot # Lower trib to Mormon Cyn (from west)Owner/Developer: Forestar Real Estate Group Field Date: 1/19/06Normal Circumstances? Heavily grazed Lat./Long.:Tributary to: Mormon Canyon County: L.A.Adjacent land use: Cattle Grazing State: California
VEGETATION: Buffer Community Type:Riparian Tree Species, % Cover Mature? Riparian/Hydrophytic Herb. Species % Cover X=Native
Populus fremontiiSalix 10 YPlatanus racemosa Non-native grassesJuglans 20 YOaks, Specify: Valley 20 Y
Riparian Sapling / Shrub SpeciesWalnut/Mulefat riparian corridor 50%Coastal sagebrush
Comments: More chaparral in streambed upstream, closer to Mormon Cyn becomes more riparian
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4”4-8”8-12”12-16Boulders Bedrock ”Gravel or Cobble Sand or Sandy loam Muck, Silt Clay or LoamComments: Erosional due to grazing
HYDROLOGY Source of Water: Spring/Seep ; Urban/Agricultural Runoff ; Can’t Determine ; OtherMaximum Depth of inundation: in. Source: Other, natural surface runoffDepth to Water Standing in Pit: >16 in. Permanent flows Intermittent flows Temporary flowsDepth to Saturated Soil: >16 in. Steep Gradient Moderate Gradient Low Gradient
Indicators:Buffer width; Ave. Width 25 Ft. DitchedChannel Banks or OHWM present:
Yes No Buffer Continuous for length GradedGroundwater Recharge? Yes ; NoComments:
STREAM CHARACTERISTICS
Stream Width Average: 10 feet ACOE Recent Erosion Evident Yes; NoStream Length (field or map calculation): 1394 Feet ACOE
2360 feet CDFGWatershed Area: 3.5 Square MilesComments: Steep/eroded banks due to heavy grazingDetermined By: R.C. Brody/ Mike Ferry Impact Sciences, Inc.
WETLAND DETERMINATION DATA FORM 1987 ACOE WETLANDS DELINEATION MANUAL
Project Site: Hidden Creeks Sample Plot #: Off-channel wtld (trib to Browns)Applicant: Field Date: 1/25/06Normal Circumstances?: No Section:Atypical Situation?: Newly grazed County: L.A.Problem Area?: State:
VEGETATION: Community Type:Tree Species, Indicator Status, %Cover Grass / Forb Species, Indicator Status, % CoverSalix lasiolepis, FACW, 10-15 % Juncus sp., OBL, 20%
Scirpus sp., OBL, 40%Speedwell? Veronica? Fescue sp., 20%
Sapling / Shrub Species, Indicator Status, % Cover Woody Vine Species, Indicator Status,Mulefat, FACW, 10%
Percent of Dominant Species Classified as OBL, FACW, or FAC: 100%Comments: Greater than 50% of the dominant species are hydrophytic species
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4 in4-8 in Clay - loam8-12 in 10 yr 2/112-16 in 10 yr 2/1Comments: all dominant plant species – OBL or FACW
Abrupt change in wetland boundary
HYDROLOGYDepth of inundation: in. Primary Indicators: Check if present:Depth to Water Standing in Pit: in. Inundated Sediment Deposits Water MarksDepth to Saturated Soil: <12 in. Saturated Drift Lines Drainage PatternsInundated at hoof prints Secondary Indicators:
Oxidized Root Channels Water-Stained LeavesChannel Banks or OHWM present:Yes No Local Soil Survey Data FAC-Neutral Test
Comments: saturated, slow flowing seep
DETERMINATION:
Hydrophytic Vegetation Criterion Met: Yes NoHydric Soils Criterion Met: Yes No (by 2 indicators)
Hydrology Criterion Met: Yes No
Sample Point Determination:Wetland Non-WetlandWaters of the United StatesWaters of the State Streambeds/Riparian Corridors
Comments: Approx .32 acre
Determined By: R. C. Brody Impact Sciences, Inc.
WETLAND DETERMINATION DATA FORM 1987 ACOE WETLANDS DELINEATION MANUAL
Project Site: Hidden Creeks Sample Plot #: Off-Site – Mormon cyn headw.Applicant: Field Date: 1/25/06Normal Circumstances?: yes Section:Atypical Situation?: no County: L.A.Problem Area?: no State:
VEGETATION: Community Type:Tree Species, Indicator Status, %Cover Grass / Forb Species, Indicator Status, % CoverSalix sp., FACW Juncus sp., OBL, 10-15%
Bulrush (scirpus), OBL, 75-80%Stinging nettleWatercress
Sapling / Shrub Species, Indicator Status, % Cover Woody Vine Species, Indicator Status,Mulefat, FACW, 10% California blackberry
Percent of Dominant Species Classified as OBL, FACW, or FAC: 100%Comments: Greater than 50% of the dominant species are hydrophytic species
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4 in4-8 in8-12 in12-16 inComments: 2 indicators (100% OBL)
HYDROLOGYDepth of inundation: in. Primary Indicators: Check if present:Depth to Water Standing in Pit: in. Inundated Sediment Deposits Water MarksDepth to Saturated Soil: surface >16 in. Saturated Drift Lines Drainage PatternsInundated at hoof prints Secondary Indicators:
Oxidized Root Channels Water-Stained LeavesChannel Banks or OHWM present:Yes No Local Soil Survey Data FAC-Neutral Test
Comments:
DETERMINATION:
Hydrophytic Vegetation Criterion Met: Yes NoHydric Soils Criterion Met: Yes No (by 2 indicators)
Hydrology Criterion Met: Yes No
Sample Point Determination:Wetland Non-WetlandWaters of the United StatesWaters of the State Streambeds/Riparian Corridors
Comments:
Determined By: R. C. Brody/Greg Ainsworth Impact Sciences, Inc.
STREAM DATA FORM GPS Data taken: Yes NoProject / Site: Hidden Creeks Sample Plot # off-site near Mason Ave.Owner/Developer: Field Date: 6/12/06Normal Circumstances? No – downstream construction Lat./Long.:Tributary to: Browns Canyon County: L.A.Adjacent land use: Residential development State: California
VEGETATION: Buffer Community Type:Riparian Tree Species, % Cover Mature? Riparian/Hydrophytic Herb. Species % Cover X=Native
Populus fremontii MulefatSalix MugwortPlatanus racemosa Upland:Juglans -laurel sumacOaks, Specify: Valley -coastal sage scrub
Riparian Sapling / Shrub Species Lotus scopariusLeymusBlack sageChaparral yuccaSalvia apianaBrassica nigra
Comments:
SOILS Mapped Series: Hydric Soils List: Yes NoProfile DescriptionDepth: Matrix Color Mottle Abundance and Contrast Texture/structure/concretions0-4”4-8”8-12”12-16Boulders Bedrock ”Gravel or Cobble Sand or Sandy loam Muck, Silt Clay or LoamComments: sorted substrate - signs of bed movement
HYDROLOGY Source of Water: Spring/Seep ; Urban/Agricultural Runoff ; Can’t Determine ; OtherMaximum Depth of inundation: in. Source: Other, natural surface runoffDepth to Water Standing in Pit: >16 in. Permanent flows Intermittent flows Temporary flowsDepth to Saturated Soil: >16 in. Steep Gradient Moderate Gradient Low Gradient
Indicators:Buffer width; Ave. Width 15 Ft. DitchedChannel Banks or OHWM present:
Yes No ACOE – 12 feet Buffer Continuous for length GradedGroundwater Recharge? Yes , at basin; NoComments:
STREAM CHARACTERISTICS
Stream Width Average: ACOE – 12 feet; CDFG – 20 feet Recent Erosion Evident Yes; NoStream Length (field or map calculation): 770 Feet
Watershed Area: Square MilesComments: Coastal sage communityDetermined By: R.C. Brody Impact Sciences, Inc.