MEMORANDUM
Date:
May 14, 2015
To:
TRPA Hearings Officer
From:
Wendy Jepson, Senior Planner
Subject
Janice and Chester Pipkin Land Capability Challenge; 833 Stateline Drive, El
Dorado County, CA; APN: 029-010-11, TRPA File no: LCAP2014-0550
Proposed Action: TRPA Hearing’s Officer review and approval of the proposed Land Capability
Challenge.
Staff Recommendation: Staff recommends the TRPA Hearings Officer approve the land
capability challenge on the parcel changing a portion of the land capability from Class 1b and
Class 7 to Class 6 the higher portions of the property. Two small areas would remain as Class 1b
near the west edge (shoreline) and center (depression), as refined by the consultant’s field
study.
Background: The parcel being challenged is shown mostly as Class 1b on TRPA Land Capability
Overlay Maps (aka Bailey Land Capability maps). The Soil Conservation Service Soil Survey of
Tahoe Basin Area, California-Nevada (Rogers, 1974) places the subject parcel within Beaches
(Be, Class 1b), Elmira loamy coarse sand, wet variant (Ev, Class 1b) and Elmira-Gefo loamy coarse
sand, 0 to 5% slopes (EfB, Class 7). These soil are composed of beach sands, plus mixed alluvium
derived from granitic parent material. The vicinity of the project has a geomorphic mapping of
E-2 for outwash, till and lake deposits (low hazard lands).
A land capability challenge was filed with TRPA on October 27, 2014. A detailed soil
investigation was conducted for this land capability challenge by Denny Churchill, CPSS, on
October 02, 2014. Mr. Churchill completed his technical report and mapping in December,
2014. On behalf of TRPA, Phil Scoles, CPSS (Terra Science, Inc.) was subcontracted to review the
soil consultant’s report and mapping and assist with TRPA’s evaluation. Three test pits in the
study were hand-excavated and hand-augered, then examined by TRPA subcontractor on
December 08, 2014. The subcontractor reviewed the soil descriptions prepared by the
applicant’s soil consultant and engaged in interactive dialogue prior to concurring with the
report and mapping. Since the neighboring parcel (APN 029-010-15 David/Darcie Kent) was also
under review for a similar land capability challenge, there were some coordination delays so
both matters would be reviewed simultaneously. After several teleconferences and email
exchanges, Mr. Churchill’s report was finalized on May 08, 2015.
AGENDA ITEM NO. V.A.
Findings: The subject parcel contains three landforms and four soil types. The lakefront
(shoreline) sediments are characterized as coarse sands that are regularly re-worked by wave
action and considered part of the Beaches (Be) soil map unit. The Be map unit slopes toward
Lake Tahoe (west), it is Class 1b and has 1 percent allowable land coverage. The next soil
eastward is an old beach deposit that is stabilized and slopes away (east) from Lake Tahoe. This
deep, somewhat excessively drained soil has loamy coarse sand textures, and no indication of
root restricting or low transmission subsurface horizons. The subsoil contains relict, variegated
features banding (horizontal layers) when this landform was created during ancient times having
higher lake elevations. The texture and internal drainage conditions are consistent with
Hydrologic Soil Group B.
A narrow band SEZ is the next soil type eastward from Lake Tahoe. This SEZ has a loamy coarse
sand topsoil layer atop an older soil. This north-south oriented soil polygon has a slightly lower
topographic setting and supports a secondary SEZ plant community near the driveway and a
primary SEZ plant commuity near the north property line. The driveway was constructed atop
the south part of this SEZ. This naturally buried soil has redoximorphic features from 18 to 25
inches from the surface. Given ongoing drought conditions preceding and during the field
investigation, it was not possible to determine if the redox features were contemporary or relict.
In the absence of shallow ground water observations during non-drought conditions, the
preponderance of evidence leans toward an SEZ designation. When drought conditions have
been reversed and ground water observations are considered reliable, the applicant may want
to consider a new land capability challenge for only this portion of the property (for possible reevaluation by TRPA). Lastly, the eastern half of the parcel contains a west-sloping soil that is
deep and somewhat excessively drained. This is part of an outwash fan that extends upslope to
U.S. Highway 50. The soil contains some relict redoximorphic features that are sufficiently deep
in the soil profile that do not infer contemporary SEZ conditions.
With a minor exception of the active beach, the soils evaluated for this land capability challenge
are different than the central concept of the Beach and Elmira wet variant soil types, as mapped
by the Soil Survey of the Lake Tahoe Basin (1974). The stabilized beach deposit soil, in the west
part of the parcel, is an unnamed soil type that is considered Class 6 (based on slope, texture,
other attributes) as per the Bailey land capability system. The outwash fan soil, in the east half
of the parcel, resembles the Gefo loamy coarse sand, 2 to 9 percent slopes soil type (GeC),
which is Class 6. The Gefo Class 6 soil is a subset of the Elmira-Gefo soil type mapped for the
eastern one-fifth of the parcel. The depression landform is unique as a buried soil (hence also
XXX), which qualifies as SEZ that is Class 1b. The table on the following page summarizes the
proposed Bailey and capability class changes.
AGENDA ITEM NO. V.A.
Land Capability District
Class 1b Beaches
Class 1b Elmira wet variant
Class 1 b SEZ (depression)
Class 6 Gefo loamy coarse sand
XXX Stabilized beach deposit
Class 7 Elmira-Gefo loamy co. sand
Total Parcel Area
Area (sq. ft.)
TRPA Land
Capability Map
25,048
26,926
0
0
0
10,645
62,619
Area (sq. ft.)
2015 LCC
3,592
0
6,588
31,713
20,726
0
62,619
This memorandum was jointly prepared by TRPA subcontractor Phil Scoles (Terra Science, Inc.)
and TRPA Senior Planner, Wendy Jepson. If you have questions on this Hearings Officer item,
please contact Wendy Jepson, at 775-589-5269 ([email protected]) or Paul Nielsen, at 775-5895249 ([email protected]).
BAILEY LAND CAPABILITY CHALLENGE FINDINGS
Assessor’s Parcel Numbers (APN)
Owner or Applicant / Contact Name
Address (Street, City, County, State)
TRPA File No. / Submittal Date
1974 Bailey Geomorphic Class and
Hazard Designation
Landform and Geology
Soil Parent Material
Slopes and Aspect
Elevation and Datum
Rock Outcrops and Surface
Configuration
SEZ and Hydrology Source
Site Information
029-010-11
Janice and Chester Pipkin (Gary Midkiff & Assoc.)
833 Stateline Avenue, South Lake Tahoe, El Dorado
County, CA
LCAP2014-0550 / October 31, 2014
Environmental Setting
E2 – Outwash, till and lake deposits (low hazard lands as
per 1974 Bailey LC Report)
Beach, stabilized beach deposit, SEZ, and outwash fan
Granitic alluvium (mixed mineralogy)
0 to 5% slopes, except with Beach zone (slightly steeper
slope)
6229.1 to 6333 msl (USBR Lake Tahoe 6223.0 datum)
No outcrops. Subtle surface undulations with slightly
higher ground immediately west of shoreline and east
half of property. Depression near west-center of
property (slopes to north)
Depression qualifies as SEZ; sustained by seasonal high
water table. See “Findings” for additional discussion.
AGENDA ITEM NO. V.A.
Vegetation
Ground Cover Condition
Site Features
Jeffrey pine, lodgepole pine, bitterbrush, wild rose on
higher ground, and lodgepole pine, aspen, horsetail,
and bluegrass in the depression.
Good.
Single family residence, detached apartment and
detached garage, and paved parking areas. Chainsaw
carved statue of Joe Montana near driveway entrance.
Field Investigation and Procedures
Denny M. Churchill, Consulting Soil Scientist
145 Cottonwood Court, Quincy, CA 95971
(530) 283-1271; [email protected]
TRPA Staff Field Dates
December 09, 2014 (soil consultant work conducted on
October 02, 2014)
SEZ Mapping / NRCS Hydric Soil
Yes, both Ev and Be soil map units identified by TRPA as
SEZ. Area meeting SEZ primary and/or secondary
criteria smaller than mapped due to local changes in
depth to ground water and non-riparian plant
community.
Additional or Repetitive TRPA
3 test pits excavated to 30 inches (at consultant soil pit
Sample Locations
locations), then soil auger to 50 inches or more.
Notable Soil Features and Depth
XXX soil is old stabilized beach deposit that separates
band of SEZ from Lake Tahoe. The dark yellow-brown
topsoil in the SEZ soil suggests that ground water may
be deeper (in contemporary times), possibly due to
urban infrastructure and upgradient development.
Areas Not Examined
Residences, garage, driveway, parking areas, and
landscaped features (other than lawn).
Consultant and Address
Specific Findings for Beaches (Be, Unstabilized Beach Deposit)
1974 Soil Survey Map Unit and
Beaches (Be, HSG A).
Hydrologic Soil Group (HSG)
2006 Soil Survey Map Unit
7174 – Marla loamy coarse sand, 5 to 15% slopes
Consultant Soil Mapping
Beach soil limited to west edge of parcel. Upper limit of
Determination and Rationale
beach soil defined by presence of Jeffrey pine trees and
retaining walls/structures. Soils are deep and consist of
lenses of sand, and coarse sand. Drainage is mostly
somewhat excessively drained, except near edge of
Lake Tahoe (shoreline varies year to year).
Slope Determination
2 to 5%
TRPA Conclusion(s)
Beaches (Be) Class 1b for unstabilized beach deposit.
This unstabilized beach deposit is significantly narrower
than mapped by 1974 soil survey.
AGENDA ITEM NO. V.A.
Specific Findings for Stabilized Beach Deposit (Unnamed XXX Soil)
1974 Soil Survey Map Unit and
Beaches (Be, HSG A).
Hydrologic Soil Group (HSG)
2006 Soil Survey Map Unit 1
7174 – Marla loamy coarse sand, 5 to 15% slopes
Consultant Soil Mapping
Soil is old beach deposits that are now stabilized
Determination and Rationale
(naturally). The soils are documented by consultant soil
pit 10/2/14-3, which are loamy coarse sand at surface,
and lenses of yellow to brown loamy sands below.
These deep soils are somewhat excessively drained and
support mostly Jeffrey pine, gooseberry, landscaping.
Slope Determination
1 to 3%
TRPA Conclusion(s)
Unnamed (XXX) Class 6 for stabilized beach deposit.
Soil lacks redoximorphic features, which differs from
Elmira wet variant soil. XXX soils have layered sand
deposit that are unlike Elmira and Gefo soils (which are
mapped further to east).
Specific Findings for Outwash Terrace (Gefo Soil)
1974 Soil Survey Map Unit and
Elmira wet variant (Ev, HSG D) and Elmira-Gefo loamy
Hydrologic Soil Group (HSG)
coarse sand, 0 to 5% slopes (EfB, HSG A).
2006 Soil Survey Map Unit
7174 – Marla loamy coarse sand, 5 to 15% slopes
Consultant Soil Mapping
Soils are situated at lower end of outwash terrace
Determination and Rationale
landform that extends upslope to U.S. Highway 50. The
soils in the east part of study area documented by
consultant soil pit 10/2/14-1, which are loamy coarse
sand textures throughout. The soil contains relict
redoximorphic features below 25 inches, while ground
water was observed at 62 inches. It appears that
streets, underground utilities and offsite disturbances
have lowered the water table for this vicinity. The plant
community is transitional between most droughty to
the east and an SEZ located near the center of site.
Slope Determination
2 to 5%
TRPA Conclusion(s)
Gefo loamy coarse sand (GeC, HSG A), Class 6
1
TRPA currently relies upon the Soil Survey of Tahoe Basin, California-Nevada (Rogers and Soil
Conservation Service, 1974), which the Bailey Land Capability system is predicated upon. The
2006 soil survey update has not yet been formally adopted by TRPA for use with land capability
matters.
AGENDA ITEM NO. V.A.
Specific Findings for Depression (SEZ)
1974 Soil Survey Map Unit and
Elmira wet variant (Ev, HSG D).
Hydrologic Soil Group (HSG)
2006 Soil Survey Map Unit
7174 – Marla loamy coarse sand, 5 to 15% slopes
Consultant Soil Mapping
SEZ is topographically lower than stabilized beach
Determination and Rationale
deposit to the west, and outwash terrace to the east.
The SEZ is part of a narrow swale that once paralleled
Lake Tahoe; however, portions have been filled, drained
or both. The consultant soil pit (10/2/14-2) shows a
naturally buried soil having redox concentrations 18 to
25 inches below the surface. Soil redox infers that this
location meets the secondary indicator for shallow
water table within 20 to 40 inches of surface. The Type
19 (Lodgepole pine) plant community indicates that
ground water may be less frequent (or persistent) than
typically for an SEZs.
Slope Determination
1 to 3%
TRPA Conclusion(s)
SEZ Class 1b for all slopes.
Attachments:
A.
Vicinity map and map showing TRPA land capability mapping
B.
Site Plan showing proposed land capability challenge recommendations
C.
Applicant’s soil consultant land capability soil report
AGENDA ITEM NO. V.A.
ATTACHMENT A
VICINITY MAP (no scale)
TRPA LAND CAPABILITY MAP
LAND CAPABILITY
Class 1b (maroon)
Class 5 (lime)
Class 7 (olive)
PIPKIN PARCEL
APN 029-010-11
AGENDA ITEM NO. V.A.
ATTACHMENT B
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ATTACHMENT C
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