I. Title Page
Southern Nevada Public Land Management Act
Research Proposal in Support of the Lake Tahoe
Restoration Act and the Lake Tahoe Environmental
Improvement Program
I.a.
Project Title:
Development of a road cut and fill land use category for the Pollutant Load Reduction
Model (PLRM)
I.b.
Theme and subtheme:
Water Quality: Sources, characterization, and transport of fine particles from urban land
uses.
I.c.
Principal Investigators:
Co-P.I.: Mark Grismer, PhD, P.E.
University of California at Davis
209 Veihmeyer Hall
Davis, CA 95616
Phone: (530) 752-3243
Fax: (530) 752-5262
megrismer@ucdavis.edu
I.d.
Co-P.I.: Michael Hogan, MS
Integrated Environmental Restoration
Services, Inc
2780 Lake Forest Road
Lake Forest, CA 96145
Phone: (530) 581-4377
Fax: (530) 581-0359
mhogan@ierstahoe.com
Grant contact person:
Debbie Hogan
Integrated Environmental Restoration Services, Inc
2780 Lake Forest Road
Lake Forest, CA 96145
Phone: (530) 581-4377
Fax: (530) 581-0359
dhogan@ierstahoe.com
I.e.
Total funding requested:
$77,066.00
I.f.
Total cost share:
$0.00 However, most of the data has already been collected.
II
Proposal Narrative
II.a Project Abstract:
Recent modeling conducted as part of the Lake Tahoe Total Maximum Daily Load (TMDL)
planning effort suggests that 72% of the fine sediment load (< 20-micron) to Lake Tahoe
originates from urban upland source areas. The Pollutant Load Reduction Model (PLRM) is
the primary modeling tool being developed to support landowners in urbanized watershed
areas in identifying sources of pollutant loading, prioritizing and implementing projects to
reduce pollutant loading (primarily fine sediment), and determining post-implementation
load reductions from various projects. The current PLRM generalizes the pollutant loading
characteristics of both paved road surfaces and adjacent cut and fill slopes in a single “roads”
land use category, which is both misleading and inaccurate. However, the PLRM was
specifically designed to incorporate new land uses as new data becomes available. This
project will leverage the most complete set of directly measured erosion data in this region
and conducted targeted rainfall simulation to develop a new land use category for road cut
and fill slopes. Additionally, using quantitative data and input from agency personnel, this
project will define functional condition classes and develop a straight-forward field protocol
that regulators and project implementers can use to identify and classify the pollutant loading
potential of cut and fill slopes at the project scale.
II.b Justification Statement:
An estimated 72% of the < 20-micron sediment load to Lake Tahoe is believed to originate
from the urban upland source category. The PLRM is the cornerstone of TMDL
implementation in urban upland areas and the primary tool to estimate load reductions
resulting from water quality improvement projects in these areas. A wide variety of land uses
are associated with urban upland source areas, including: residential and commercial
development, forested parcels, paved roadways and parking lots, and in most areas,
significant cut and fill slopes. In the current PLRM, road cut and fill slopes are combined
with road shoulders and paved surfaces into a single “roads” land use. This generalized road
land use is likely to be misleading and inaccurate, as the types and volumes of fine sediment
and other pollutants and their transport mechanisms from disturbed cut and fill slopes are
known to be quite different from adjacent paved road surfaces.
Achieving fine sediment load reduction goals set forth in the Tahoe TMDL depends on an
accurate understanding and characterization of sediment source areas. The developers of the
PLRM foresaw the need to define new land uses (such as road cut and fill slopes) and
designed the model to be updated easily as new land uses are developed. The development
of a road cut and fill slope land use will improve the selection, design, implementation and
crediting of water quality improvement projects, and will therefore assist in reaching TMDL
goals.
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II.c. Concise background and problem statement:
Construction of roads and other development during the last 50 years in the Lake Tahoe
Basin has increased sediment and nutrient loading into the Lake and contributed to the loss
of Tahoe’s exceptional clarity by 25%, from approximately 30 to 21 m. The Lake Tahoe
TMDL will be requiring landowners to determine the sources and quantities of fine sediment
and nutrients originating from areas under their management and to implement projects to
meet load reduction targets. Recent TMDL-related modeling has estimated that 72% of the
< 20-micron sediment load to Lake Tahoe originates from urban upland source areas.
Several studies using rainfall simulation have produced valuable quantitative data
characterizing a wide range of disturbed and treated conditions on steep disturbed soil areas,
including road cut and fill slopes and ski runs in the Lake Tahoe region (Grismer et al. 20042008). This research has shown that steep disturbed slopes, such as road cuts, may be
producing sediment yields up to an order of magnitude higher than relatively undisturbed or
“native” conditions (Grismer and Hogan 2004, Grismer et al. 2008). The data collected as
part of this research by Grismer, Hogan, and others was used to develop treatment tiers,
functional condition classes, and associated Basin-wide load reduction estimates for forested
upland areas for the Lake Tahoe TMDL.
The PLRM is the primary modeling tool that will be used to support landowners in
identifying sources of pollutant loading in urbanized watersheds, prioritizing and
implementing projects to reduce pollutant loading (primarily fine sediment), and determining
post-implementation load reductions from various projects. The “roads” land use in the
PLRM currently generalizes the pollutant loading characteristics of both paved road surfaces
and adjacent cut and fill slopes, which is both misleading and inaccurate. However, the
PLRM was specifically designed to define new land uses and refine existing land uses as data
becomes available. Most of the data required to adequately define a separate road cut and fill
land use with range of disturbed and treated conditions and associated load reductions has
already been collected. Additionally, there is a need to define specific functional condition
classes that are supported by quantitative data and to develop a straightforward field
protocol that regulators and project implementers can use to identify and classify the
pollutant loading potential of cut and fill slopes at the project scale. Until cut and fill slopes
are classified and characterized as a discrete land use within the PLRM, load reduction
estimates will likely continue to under-predict sediment loading from urban areas and miss
opportunities to better understand and treat these persistent and long-term sources of fine
sediment.
II.d. Goals, objectives, and hypotheses to be tested:
The goals of this study are to: 1) improve understanding of sediment loading (amounts and
particle size classes) from road cut and fill slope sources; 2) inform the selection, design, and
implementation of water quality improvement projects to maximize load reduction
effectiveness; and 3) improve the predictive accuracy of the PLRM for road cut and fill areas
to support achievement of TMDL goals.
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The project objectives are to: 1) develop a new land use category for road cut and fill slopes
for the PLRM that leverages existing quantitative data and builds on the treatment tiers and
functional condition classes already developed in earlier stages of the TMDL (Lahontan,
2007, p.189); and 2) develop well-defined classifications and field identification protocols for
a range of disturbed and treated cut and fill slope conditions with associated loading
potentials.
The primary hypothesis to be tested is that cut and fill slopes exhibit a wide range of
characteristic runoff concentrations, depending on level of disturbance and/or subsequent
level of treatment (i.e. functional condition class). Therefore, clear definition of functional
condition classes for road cut and fill slopes will improve our ability to identify load
reduction opportunities and accurately track fine sediment load reductions in urban upland
areas.
II.e. Approach, methodology and location of research:
Since the majority of the necessary data collection has already been completed, this project is
planned to be completed in one year. Existing quantitative rainfall simulation data from cut
and fill slopes in the Lake Tahoe region will be analyzed and stratified into a minimum of
four classes (functional condition classes) based on differences in characteristic runoff
concentration (combination of Ksat and fine sediment concentration). At the low end of the
functional condition spectrum are highly compacted slopes with minimal infiltration and low
vegetation cover, while at the high end are slopes with low soil density, high infiltration, and
high vegetation cover. There is sufficient data to define the high and low ends of the
functional condition spectrum. Therefore, targeted rainfall simulations will be conducted at
10 additional road cut and fill sites in the Lake Tahoe region to characterize the two
remaining functional classes. Additional simulations will directly measure Ksat (infiltration)
and runoff samples will be analyzed for total sediment, sediment concentration, and particle
size distribution using methods consistent with previous research (Grismer and Hogan 2004,
Grismer et al. 2008). New and existing data will be compiled and summarized to provide
characteristic runoff concentrations for each pollutant of concern 1 for each functional
condition class. An accompanying table of soil hydrologic properties (Ksat and infiltration
rate) for each functional condition class will also be prepared. A straightforward field
identification protocol will be developed that agency personnel and project implementers
can use to classify cut and fill slopes based on their functional condition and associated
pollutant loading potential both before and after project implementation. Lastly, an
application guide will be produced for the new PLRM road cut and fill land use category.
The application guide will describe key assumptions in the modeling framework and provide
model users with guidance on appropriately modeling erosion and treatment scenarios for
cut and fill slopes.
Pollutants of concern include: Total Suspended Sediment, fine sediment (< 20 microns), Total Nitrogen, Dissolved
Nitrogen, Total Phosphorous, Dissolved Phosphorous
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II.f. Relationship of the research to previous relevant research, monitoring,
and/or environmental improvement efforts:
This project leverages the data and field experience of more than 10 years of quantitative,
peer-reviewed erosion research in the Lake Tahoe region that has been conducted by the
PI’s, Dr. Mark Grismer and Michael Hogan. This work has produced the most complete set
of directly measured erosion data in this region, which is ideally suited for defining a new
road cut and fill land use for the PLRM. Using this data, Hogan and Grismer led the
development of load reduction estimates for forested upland areas in the planning phase of
the Tahoe TMDL. This project will build on the statistical analyses and functional condition
classes that were previously developed and incorporated into Basin-wide TMDL modeling
efforts to ensure seamless integration with earlier phases of TMDL development.
This project also compliments the proposed El Dorado County project that seeks to
characterize the pollutants in runoff from paved road surfaces, as cut and fill slopes are
known to contribute fine sediment to adjacent road surfaces. There are likely to be cost
savings (and valuable research synergy) if both projects are selected for funding, as rainfall
simulation may be able to be conducted on road surfaces and adjacent cut and fill slopes
without additional mobilization costs.
II.g. Strategy for engaging with managers:
The PI’s will work closely with local agency managers on the development of the functional
condition classes. Guidance will be sought from the Storm Water Quality Improvement
Committee (SWQIC), local EIP project implementers, and those developing and refining the
PLRM. It is critical that both the assembled data and the end users of the PLRM guide the
development of the functional condition classes as well as the field identification methods.
II.h. Description of deliverables/products:
The primary deliverable will be a fully functional PLRM land use category for road cut and
fill slope areas with accompanying documentation. The following products will be submitted
and posted on the TIIMS website:
• Final report summarizing project, research methods and results.
• Table of input parameters for PLRM road cut and fill land use category
including: characteristic runoff concentrations for each pollutant of concern
for each functional condition class and accompanying table of soil hydrologic
properties (Ksat and infiltration rate) for each functional condition class.
• Field identification protocols for functional condition classes (including
summary of agency input).
• PLRM application guide for modeling road cut and fill land use category.
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It is also the goal of the PI’s that the results of this project be published in one or more peerreviewed journals.
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III
Schedule
Given that the majority of the data exists from previous work by the PI’s, this project will be
fully complete within one year. The following table provides a brief overview of the project
schedule.
Milestone
Est. Start Date
Est. End Date
Grant award and contracting
June 2009
July 2009
Analysis of existing data and site selection
July 2009
August 2009
Quarterly progress report
Field work (rainfall simulations)
October 2009
August 2009
Quarterly progress report
Lab analyses and data entry
October 2009
October 2009
October 2009
Quarterly progress report
February 2010
January 2010
Data analysis and PLRM parameter development
February 2010
March 2010
Final report, PLRM input data table, field
identification protocols, PLRM application guide
(upload to TIIMS)
February 2010
April 2010
Project close out
May 2010
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IV. References
Battany MC, Grismer ME. 2000. Development of a portable field rainfall simulator system
for use in hillside vineyard runoff and erosion studies. Hydrological Processes 14:
1119–1129.
Curtis, M.J., M.E. Grismer and V.P. Claassen. 2007. Effect of compost incorporation on
infiltration capacity and erosion control from a decomposed granite roadcut. J. Soil &
Water Conservation 62(5):338-344.
Fristensky, A. and M.E Grismer. 2008. A modeling approach for ultrasonic soil aggregate
stability assessment. Catena 74:153-164.
Fristensky, A. and M.E Grismer. 2008. Aggregate stability and particle-size analyses of
cohesionless volcanic and granitic soils 2. Treatment Implications. Catena in-press.
Grismer, M.E. and M.P. Hogan. 2004. Evaluation of Revegetation/Mulch Erosion Control
Using Simulated Rainfall in the Lake Tahoe Basin: 1. Method Assessment. Land
Degradation & Dev. 13:573-588.
Grismer, M.E. and M.P. Hogan. 2005. Evaluation of Revegetation/Mulch Erosion Control
Using Simulated Rainfall in the Lake Tahoe Basin: 2. Bare Soil Assessment. Land
Degradation & Dev. 16:397-404.
Grismer, M.E. and M.P. Hogan. 2005. Evaluation of Revegetation/Mulch Erosion Control
Using Simulated Rainfall in the Lake Tahoe Basin: 3. Treatment Assessment. Land
Degradation & Dev. 16:489-501.
Grismer, M.E. and A.L. Ellis. 2006. Sediment Particle-size Distributions in Runoff from
Disturbed Soils in the Lake Tahoe Basin. California Ag. 60(2):72-76.
Grismer, M.E., A.L. Ellis and A. Fristensky. 2008. Runoff Sediment Particle-sizes
associated with Soil Erosion in the Lake Tahoe Basin, USA. Land Degradation &
Dev. 19:331-350.
Grismer, M.E. 2007. Soil Restoration and Erosion Control: Quantitative Assessment in
Rangeland and Forested areas. Invited to ASABE Transactions Soil & Water
Centennial Collection. 50(5):1619-1626.
Grismer, M.E., C. Shnurrenberger, R. Arst and M.P. Hogan. 2008. Integrated Monitoring
and Assessment of Soil Restoration Treatments in the Lake Tahoe Basin. Environ.
Monitoring & Assessment. In-press.
Grismer, M.E. 2008. Erosion Modeling for Land Management – Scaling from plots to
small forest catchments in the Tahoe Basin. J. Environ. Management. Submitted.
Jassby, Alan D. et al. Origins and scale dependence of temporal variability in the
transparency of Lake Tahoe, California-Nevada. Limnology and Oceanolgraphy 11
(2): 282-294
Lahontan Regional Water Quality Control Board. Lake Tahoe TMDL Pollutant Reduction
Opportunity Report. September 2007.
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Reuter, J. E. et al., (2003). An integrated watershed approach to studying ecosystem health
at Lake Tahoe, CA-NV. Managing for Healthy Ecosystems, 1283-1298.
Roberts, David M. and Reuter, John E. Draft Lake Tahoe Total Maximum Daily Load
Technical Report, California and Nevada, September 2007.
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