HomeMy Public PortalAbout4g-HydroNOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
IV. SETTING, IMPACTS AND MITIGATION MEASURES
G. HYDROLOGY AND STORM DRAINAGE
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G. HYDROLOGY AND STORM DRAINAGE
This section describes the existing hydrological setting for the Plan Area, including runoff,
drainage, and water quality based on available information from published and unpublished
reports, site-specific environmental investigation reports, internet sources, and a recon-
naissance of the site conducted in October 2006. Based on the information reviewed, this
section identifies impacts that may result from project development, and provides mitiga-
tion measures to reduce potential impacts to a less-than-significant level, if feasible.
1. Setting
A description of the existing conditions related to hydrology and storm drainage is provided
below.
a. Climate. The Truckee area is located within a climate ‘island’ that encompasses the
southern Cascade and Sierra mountain ranges and is characterized as humid-continental.
The climate is influenced seasonally by both polar and tropical weather patterns, with
relatively large changes in temperature and precipitation throughout the year.1 In Truckee,
for the period between 1948 and 2007, the annualized average high temperature is 59.2º
Fahrenheit (F); the average low is 27.6ºF. A high of 100.0ºF occurred on 11 July 2002, and a
low of minus (-) 23.0ºF on February 27, 1962. During this period of record, the mean annual
precipitation in the site vicinity is approximately 31.6 inches. Annual precipitation has
varied from 16.04 inches (1976) to 54.62 inches (1996), with a one-day high of 5.2 inches
of precipitation on February 1, 1963. Typically, about 75 percent of the precipitation occurs
during the winter and spring (December to May).2 Of this precipitation, the average annual
snowfall amounts to 203.6 inches; with a high occurring in 1952 of 401.4 inches of snow.3
b. Runoff and Drainage. The approximately 75-acre Plan Area is located within a
relatively flat semi-developed area. The existing ground surface elevation is approximately
5,800 feet above sea level (National Geodetic Vertical Datum [NGVD]) with a slope of
approximately 1.5 percent to the east. Trout Creek crosses the site, running roughly parallel
to and near the northern boundary, and the Truckee River is approximately 200 feet south
1 Lutgens, Frederick K., Tarbuck, Edward J., 1979, The Atmosphere: an introduction to
meteorology, Prentice Hall.
2 Western Regional Climate Center, 2007, General Climate Summary, Station 049043,
Truckee, CA, accessed February 6, 2008 at: www.wrcc.dri.edu.
3 The water content of snow is variable. Many snows that fall at temperatures close to 32°F
and snows accompanied by strong winds contain approximately one inch of water per 10 inches of
snowfall, however, ten inches of fresh snow can contain between 0.10 and 4.0 inches of water
depending on crystal structure, wind speed, temperature, and other factors. The majority of U.S.
snows fall with a snow-to-water ratio of between 10:1 and 4:1.
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
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of, and parallels, the southeastern edge of the site.4 The Plan Area is largely covered with
pervious surfaces with limited areas of pavement and buildings. Most of the precipitation at
the site encounters the pervious surfaces, and either infiltrates, pools (or accumulates if
snow) and evaporates, or drains by sheetflow to Trout Creek, which joins the Truckee River
just east of the site. The Plan Area is located in the Trout Creek Planning Watershed (PWS)
surface water planning area,5 of the Truckee River Hydrologic Area (HU No. 635.20),6 and
the Martis Valley Groundwater Region.7
c. Snow Removal. The Town of Truckee has developed polices and procedures for snow
and ice removal, as implemented by the Public Works Department.8 Plowing begins after
accumulations reach three inches or more and crews follow a prioritized plan for street
clearing. Snow is initially plowed to the side of the street in windrows with special attention
given to school bus routes, and main arterial streets. Plowing and snow removal operations
may be ongoing 24-hour per day, and last several days after a major storm. Additional snow
removal to widen the useable portion of the roads, after the initial pass, may not occur for
several days. Application of sand in not usually initiated during an ongoing snowfall event
as additional plowing would remove the sand from the roadway, potentially requiring re-
sanding.9
d. Flooding. The proposed Plan Area is mapped by the Federal Emergency Management
Agency (FEMA) as flood Zones A (100-year), B (500-year) and C (minimal flooding) (Figure
IV.G-1). The Flood Zone A area is an irregular shaped zone along the margins of Trout Creek
that expands south of Trout Creek and east of Donner Pass Road to encompass roughly
one-quarter of the area inside the loop of the present ‘balloon’ track. Farther east, Zone A
varies in width, but is shown to average approximately 200 feet in width, with wider areas
mapped behind obstructions presented by creek crossing structures. The Zone B area is at
the west end of the project. It originates outside the Plan Area where Trout Creek passes
under Jibboom Street. Within the project, it is the area from about 300 feet east of Brockway
4 USGS, 2008, The National Map Viewer, NED Contiguous U.S. 1/3W Arc Second Elevation Data,
accessed at: http://nationalmap.gov/index.html, on February 6, 2008.
5 California Watershed Portal, 2008, Mapping Website, accessed 2-4-2008 at:
http://cwp.resources.ca.gov/.
6 Lahontan Regional Water Quality Control Board (LRWQCB), 1995 as amended trough 2005,
Water Quality Control Plan for the Lahontan Region: North and South Basins, December.
7 California Department of Water Resources, 2006, California Groundwater Bulletin 118,
Martis Valley 6-67, 20 January, accessed 2-4-2008 at: http://www.groundwater.water.ca.gov/.
8 Town of Truckee, City Ordinances, Chapter 10.17 Snow Removal.
9 Town of Truckee, 2005. Snow Removal. Accessed 7/1/08 at:
www.townoftruckee.com/snowremov.html
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Road to E Street and then southeast across the width of the project to East River Street (and
the Truckee River beyond). The remaining portions of the site are mapped as Zone C.10
Restoration of Trout Creek to a more stable and naturally-functioning creek channel corridor
upstream and within the Master Plan Area has been proposed by the Town of Truckee and
an independent CEQA analysis is being completed for the restoration project. Approximately
6,000 feet of creek channel corridor would be restored with a combination of channel
modification and floodplain restoration. The restoration plan is a separate project from the
proposed Master Plan project, but as the areas overlap and some Master Plan elements (i.e.,
balloon track relocation and two associated creek crossings, Glenshire Drive reroute, and
site grading activities) are interdependent with the restoration, the creek restoration efforts
would be coordinated with Master Plan development.11 It is anticipated that the restoration
of Trout Creek would, when completed, result in a reduction in flooding in the restoration
area, including the area of the proposed Master Plan project. Changes in the 100-year
floodplain within the area of the Trout Creek re storation, as compared to the most recent
Flood Insurance Rate Map (FIRM), would be resolved by the Letter of Map Amendment
(LOMA) process with FEMA, possibly resulting in new boundaries for the 100- and 500-year
flood zones.12
Catastrophic structural dam failure can be caused by an earthquake or overflow. The Plan
Area is not within a mapped dam failure flood inundation hazard area.13 The site is not
adjacent or near a substantial body of standing water, therefore the location and elevation
of the site would be expected to preclude exposure of the site to local coastal hazards, such
as tsunamis, seiche, or extreme high tides. The nearest substantial bodies of water, Donner
Lake, 1.6 miles to the west, and Lake Tahoe, 10 miles to the southeast, do not present an
imminent tsunami or seiche treat to the Plan Area.14,15
10 Federal Emergency Management Agency (FEMA), 1983, Flood Insurance Rate Map (FIRM),
Nevada County, California, Community Panel Number 060210 0508 B, January 19, accessed 2-5-08 at:
http://www.msc.fema.gov/.
11 Town of Truckee, 2007, Truckee Railyard Master Plan: Public Review Draft, 26 November,
2007.
12 Town of Truckee, 2006. Request for Proposals, Trout Creek Restoration Project, 12 October.
13 Governor's Office of Emergency Services (OES), 2002, Merged Dam Inundation Maps for
California, GIS files on DVD, State of California.
14 Ichinose, Gene A., et al., 1999, The Potential Hazard From Tsunami And Seiche Waves
Generated By Future Large Earthquakes Within The Lake Tahoe Basin, California-Nevada, UNR, Nevada
Seismological Laboratory MS-174, Geophysical Research Letters, Vol. 27, pgs. 1203-1206. April 15,
2000.
15 Town of Truckee, 2007, General Plan 2025 EIR.
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NOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
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e. Water Quality. The quality of surface water and groundwater in the vicinity of the Plan
Area is affected by past and current land uses at the site and within the watershed and the
composition of geologic materials in the vicinity. Water quality in surface and groundwater
bodies is regulated by the State Water Resources Control Board (SWRCB) and Regional Water
Quality Control Boards (RWQCB). The Plan Area is under the jurisdiction of the Lahontan
Regional Water Quality Control Board (Water Board), which is responsible for implementation
of State and federal water quality protection regulations and guidelines in the upper Sierra
Nevada area and as far south as the Mojave area and Lake Arrowhead. The Water Board
implements the Water Quality Control Plan (Lahontan Basin Plan), a master policy document
for managing water quality issues in the region. The Basin Plan establishes beneficial water
uses for waterways and water bodies within the region. Designated beneficial use
classifications for the Truckee River, which is the receiving water for drainage from the Plan
Area, include; Agricultural Supply, Cold Freshwater Habitat, Commercial and Sportfishing,
Freshwater Replenishment (of surface water bodies), Ground Water Recharge, Industrial
Service Supply, Migration for Aquatic Organisms, Municipal and Domestic Water Supply,
Hydropower Generation, Rare, Threatened or Endangered Species Habitat, Water Contact
Recreation, Water Non-Contact Recreation, Spawning, Reproduction and Development
Habitat, and Wildlife Habitat. The Truckee River is listed on the State’s 303(d) list as
impaired for sedimentation and siltation. Causes listed include construction and land devel-
opment, highway, road and bridge construction, streambank modifications and
destabilization, and nonpoint sources.
(1) Stormwater. Runoff water quality is regulated by the National Pollutant
Discharge Elimination System (NPDES) Program (established through the Clean Water Act);16
the NPDES program objective is to control and reduce pollutant discharges to water bodies.
There are two NPDES permits that are relevant to the proposed project.
NPDES General Permit for Discharges of Stormwater Associated with Construction
Activity (99-08-DWQ) commonly referred to as the Construction General Permit
(CGP). Projects anywhere in the State of California17 disturbing more than one acre of
land during construction are required to file a Notice of Intent (NOI) with the appropriate
Regional Water Board to be covered under the CGP for discharges of stormwater
associated with construction activity. A developer must propose control measures that
are consistent with the CGP. A Storm Water Pollution Prevention Plan (SWPPP) must be
developed and implemented for each site covered by the CGP. The SWPPP should contain
a site map(s) which shows the construction site perimeter, existing and proposed
16 US Environmental Protection Agency, 2007, NPDES Overview, accessed February 7, 2008 at:
http://cfpub.epa.gov/npdes/index.cfm.
17 There are two Regional Water Boards that have adopted their own permits to cover
discharges from construction activity greater than 1 acre within specific watersheds. The areas are the
Lake Tahoe hydrologic unit (Region 6) and the San Jacinto Watershed (Region 8). Owners of
construction projects in these two watersheds must apply for coverage under the applicable Regional
Board permits rather than the statewide Construction General Permit.
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buildings, lots, roadways, stormwater collection and discharge points, general
topography both before and after construction, and drainage patterns across the
project. The SWPPP must list Best Management Practices (BMPs) the discharger will use
to protect stormwater runoff and the placement of those BMPs. Additionally, the SWPPP
must contain a visual monitoring program; a chemical monitoring program for "non-
visible" pollutants to be implemented if there is a failure of BMPs; and a sediment
monitoring plan if the site discharges directly to a water body listed on the 303(d) list
for sediment. Section A of the CGP describes the elements that must be contained in a
SWPPP.
A revision to the CGP is currently undergoing review, and may be adopted by the Water
Board during 2008. Some of the changes proposed in the new Permit include required
numeric action levels for pH, turbidity, and total petroleum hydrocarbons, additional
BMPs, effluent monitoring and reporting, active treatment systems, performance
standards for hydromodification impacts, technical training for staff, and annual report
requirements.
NPDES General Permit for the Discharge of Stormwater from Small Municipal
Separate Storm Sewer Systems. Locally, this NPDES program is administered by the
regional Water Board. The Water Board has delegated responsibility for implementation
of stormwater regulations in the vicinity of the Plan Area to the Town of Truckee. The
General Permit for the Discharge of Storm Water from Small Municipal Separate Storm
Sewer Systems, Water Quality Order (WQO) No. 2003-0005-DWQ (Small MS4 General
Permit), requires that Dischargers (in this case the Town of Truckee) develop and
implement a Storm Water Management Program (SWMP). The SWMP describes the BMPs,
measurable goals, and time schedules for implementation as well as assigns
responsibility for each task. The MS4 General Permit requires all permittees to develop
and implement a SWMP designed to reduce the discharge of pollutants through their
MS4s to the Maximum Extent Practicable (MEP).
A SWMP has been prepared by the Town of Truckee and has been approved by the Water
Board (Permit No. 6A290712005).18 The SWMP describes the programs to be implemented in
the Town of Truckee to control stormwater pollutants.
The SWMP includes guidance for new development and significant redevelopment projects.
The SWMP includes by reference Attachment 4 of the General Permit, which provide specific
design standards applicable to the project based on the size and nature of the proposed
project. As specified by the MS4 General Permit, all new development projects, regardless of
size, should incorporate appropriate source control and site design measures that minimize
stormwater pollutant discharges to the maximum extent practicable. The proposed project
18 Vaughan, Mike, 2008. Senior Engineer, Truckee Public Works Department. Verbal
communications with RRM Design Group. August 1.
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would be required to comply with the terms of the SWMP and WQO Attachment 4, including
(but not limited to):
Numeric Sizing Criteria for Pollutant Removal Treatment Systems. The project must
include source controls, design measures, and treatment controls to minimize
stormwater pollutant discharges. Treatment controls must be sized to treat a specific
amount – about 85 percent – of average annual runoff.
Operation and Maintenance of Treatment Measures. Treatment controls often do not
work unless adequately maintained. The permit requires an operations and maintenance
(O&M) program, which includes: 1) identifying the properties with treatment controls; 2)
developing agreements with private entities to maintain the controls, and 3) periodic
inspection, maintenance (as needed), and reporting.
Limitation on Increase of Peak Storm Water Runoff Discharge Rates. Urbanization
creates impervious surfaces that reduce the landscape’s natural ability to absorb water
and release it slowly to creeks. These impervious surfaces increase peak flows in creeks
and can cause erosion. Projects must evaluate the potential for this to occur and provide
mitigation as necessary.
State law authorizes the State and Regional Water Boards to set prohibitions against the
discharge of waste in certain areas or under certain conditions. These prohibitions may
apply to discharges to groundwater or surface water or both (CA Water Code § 13280-
13284). The prohibitions do not directly prohibit the construction of new subdivisions,
development of environmentally sensitive lands, or development which is not offset by
remedial erosion control measures. The discharge of sediment and nutrients which results
from such development is prohibited by the Lahontan Basin Plan. The prohibitions related to
new development can be enforced through conditions in site-specific waste discharge
permit requirements and/or NPDES stormwater permits.19
(2) Groundwater. There is a potential for soil contamination resulting from former
industrial activities on properties within the proposed Plan Area to have occurred, which
could affect groundwater quality. Groundwater testing and remediation has been ongoing
since 1998 at the Berry-Hinckley site on Church Street. The fall 2007 quarterly remediation
progress report for the Berry-Hinckley site indicates ground water levels at the Plan Area
vary seasonally from approximately 20 to 60 feet below the ground surface; also, the report
includes historical data detailing the impacts to groundwater resulting from an earlier
release at the site.20 The remediation of soil and groundwater contamination at Berry-
19 LRWQCB, 2005. op. cit.
20 McGinley & Associates, 2007. Groundwater Monitoring and Remediation Report – Third
Quarter 2007, Former BHI Store #545, 10161 Church Street, Truckee, CA. LUSTIS #6T0276A, prepared
for Consolidated Nevada Corporation, Reno, NV; Lahontan Regional Water Board; State of California;
and Nevada County Environmental Health Department.
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Hinckley is nearly complete; details are discussed in Section IV.J, Hazards and Public Safety,
of this EIR.
Truckee Development Associates, LLC contracted with environmental consulting firms to
determine the extent of soil and ground water contamination. Initial sampling within the
Hotel parcel phase one area (see Figure IV.J-1 in the Hazards and Public Safety section)
indicates that it is likely that no further remediation would be required in this area.
Sampling is planned for the adjacent Donner Pass Road alignment which is to be
abandoned, and is expected to be similar to the phase one area. Results of the investigation
for the area within the balloon track indicate required remediation will likely be limited to
removal of petroleum-contaminated near-surface soils. The eastern portion of the site was
determined to require no remediation.21 Based on the information provided by the
proponent’s consultants as cited in the Draft Master Plan, groundwater within the Plan Area
(except in the area of the Berry-Hinckley facility) is unaffected by past uses.
f. Town of Truckee Policies. Town policies related to Hydrology and Water Quality are
listed below.
2025 General Plan Policies
Goal SAF-2: Reduce hazards associated with flooding.
P2.1: Continue to work with appropriate local, State and federal agencies (particularly FEMA) to
maintain the most current flood hazard and floodplain information and use it as a basis for
project review and to guide development in accordance with federal, State and local standards.
P2.2: Continue to participate in the National Flood Insurance Program (NFIP).
P2.3: Incorporate stormwater drainage systems in development projects to effectively control
the rate and amount of runoff, so as to prevent increases in downstream flooding potential.
P2.4: Discourage development within the Truckee River floodplain and adjacent to other
waterways to minimize risks associated with flooding.
Goal LU-4: Coordinate land development with provision of services and infrastructure.
P4.5 Require new infrastructure and development to be designed and built to manage
stormwater runoff and to minimize or eliminate harmful impacts to property prone to flooding,
water quality, and riparian, wetland, and meadow habitats. When infrastructure is replaced or
retrofitted, require the upgrading of stormwater management systems to minimize or eliminate
these impacts.
Goal COS-11: Protect water quality and quantity in creeks, lakes, natural drainages and groundwater
basins.
P11.1: Minimize excessive paving that negatively impacts surface water runoff and groundwater
recharge rates.
21 Town of Truckee, 2007, Truckee Railyard Master Plan: Public Review Draft, 26 November,
2007.
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P11.2: Protect surface and groundwater resources from contamination from runoff containing
pollutants and sediment, through implementation of the Regional Water Quality Control Board’s
Lahontan Region's, Best Management Practices.
P11.3: Cooperate with State and local agencies in efforts to identify and eliminate all sources of
existing and potential point and non-point sources of pollution to ground and surface waters,
including leaking fuel tanks, discharges from storm drains, auto dismantling, dump sites,
sanitary waste systems, parking lots, roadways, and logging and mining operations.
P11.4: Enforce guidelines set forth by the Regional Water Quality Control Board Lahontan
Region regarding waste discharge associated with domestic wastewater facilities such as septic
tank leach-field systems.
P11.5: Require new development projects that have the potential to impact local water quality
through increased stormwater runoff or erosion to include analysis of water quality impacts as a
component of project review and to integrate mitigation measures that would reduce identified
impacts to an acceptable level.
P11.6: Utilize Low Impact Development and Best Management Practices established in the
Regional Water Quality Control Board’s Truckee River Hydrologic Unit Project Guidelines for
Erosion Control, and the State of California Stormwater Best Management Practices Handbooks,
and other resources such as the Practice of Low Impact Development (US Department of
Housing and Urban Development) and Water Quality Model Code and Guidebook (State of
Oregon, Department of Land Conservation and Development) as guidelines for water quality
and erosion control measures required by the Town.
P11.9: Recognize the importance of stormwater management in protecting all water resources
in Truckee, for example, flood control, surface and ground water quality, and river, stream and
lake health.
Actions
A11.1: Establish coverage limitations for impervious paved areas in new development, and
encourage the use of permeable paving materials and other water quality management
practices to minimize stormwater runoff and the loss of groundwater recharge from paving.
Such limitations shall take into account Policy P13.2 under Goal COS-13, concerning particulate
matter pollution associated with unpaved roads.
1997 Downtown Specific Plan (DSA) Policies
DSA Policy 13: Pursue environmental characterization of critical sites and develop strategies to
resolve soil contamination problems that may hinder development Downtown.
DSA Water Quality Protection Policies: New private and public development including new
parking areas shall comply with the Lahontan Erosion Control Guidelines and BMPs.
The Town shall work with responsible property owners and Lahontan to identify and remedy
existing untreated discharges within the DSA to implement General Plan Conservation and Open
Space Policy 63.
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2. Relevant Railyard Draft Master Plan Policies
The Draft Master Plan includes specific polices related to hydrology and storm drainage.
New development within the Master Plan Area would be subject to the following hydrology
and storm drainage policies within the Draft Master Plan:
Policies
4.b: Achieve multiple resource conservation goals through the design of public open spaces.
Open space can provide natural habitat for wildlife, storm water management/ infiltration and
winter snow storage.
4.d: Require site design to incorporate Low Impact Development (LID) principles including
storm water infiltration, retention and treatment on site, consistent with NPDES storm water
standards.
4.f: Restore Trout Creek while striving to balance natural, wildlife, habitat, flood control, social
and cultural elements (including recreation and interpretive signage) to create a healthy and
sustainable environment.
4.g: Embrace Trout Creek as an urban stream and reinforce this natural asset while creating a
place for human enjoyment.
3. Impacts and Mitigation Measures
This section analyzes the impacts related to hydrology and water quality that could result
from implementation of the Draft Master Plan. The subsection begins with criteria of signifi-
cance, which establish the thresholds for determining whether a project impact is signifi-
cant. The latter part of this section presents the potential impacts and recommends
mitigation measures, as appropriate.
a. Criteria of Significance. The project would have a significant effect on hydrology or
water quality if it would:
Violate any water quality standards or waste discharge requirements.
Substantially deplete groundwater supplies or interfere substantially with groundwater
recharge such that there would be a net deficit in aquifer volume or a lowering of the
local groundwater table level (e.g., the production rate of pre-existing nearby wells
would drop to a level which would not support existing land uses or planned uses for
which permits have been granted).
Substantially alter the existing drainage pattern of the site or area, including through
the alteration of the course of a stream or river, in a manner which would result in
substantial erosion or siltation on- or off-site.
Substantially alter the existing drainage pattern of the site or area, including through
the alteration of the course of a stream or river, or substantially increase the rate or
amount of surface runoff in a manner which would result in flooding on- or off-site.
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Create or contribute runoff water which would exceed the capacity of existing or
planned stormwater drainage systems or provide substantial additional sources of
polluted runoff.
Otherwise substantially degrade water quality.
Place housing within a 100-year flood hazard area as mapped on a federal Flood Hazard
Boundary or Flood Insurance Rate Map or other flood hazard delineation map.
Place within a 100-year flood hazard area structures which would impede or redirect
flood flows.
Expose people or structures to a significant risk of loss, injury or death involving
flooding, including flooding as a result of the failure of a levee or dam.
Inundation by seiche, tsunami, or mudflow.
The significance criteria identified above are based on Section 15065 and Appendix G of the
CEQA Guidelines.
b. Less-than-Significant Hydrology and Storm Drainage Impacts. The Master Plan Area
would not be exposed to threats from coastal flooding hazards, including tsunami, extreme
high tides, or seiche. The site is not located within a mapped dam failure inundation zone.
These potential impacts are therefore less than significant.
The restoration of Trout Creek is a separate project being conducted by the Town of
Truckee, and the goals of this project include reducing flooding hazards, improving the
riparian habitat, and minimizing erosion and sedimentation to the creek. As part of the
restoration project, a new bridge has been completed at the intersection of Trout Creek and
Donner Pass Road. Design and restoration plans for additional sections of the creek both
upstream and downstream of the bridge are currently under development by the Town and
its consultants. The downstream sections will be designed in coordination with the
proposed Master Plan for the Railyard redevelopment.22 Elements of the Railyard Draft
Master Plan are specifically designed to work in conjunction with the creek restoration
project. The Railyard Draft Master Plan proposes the relocation of the existing balloon track,
which currently constricts the Trout Creek channel causing flow impedance and backwater
flooding during high flow events. As part of the separate restoration project, Trout Creek
would be realigned and new culverts and/or bridges constructed during the phased
development of the proposed project. Relocation of the balloon track further to the east
would allow the current creek to be widened to handle increased flows. The proposed
Master Plan project would alter the course of Trout Creek though keeping near the
centerline of the current alignment, include two new creek crossings for relocation of the
22 Town of Truckee, 2007. Capital Improvement Projects of 2007. Accessed 6/2708 at:
www.townoftruckee.com/CIP%202007.html.
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balloon track, widen the channel to accommodate increased flow during 100-year flood
events, introduce opportunities for meanders to form in the widened bed, and enhance
riparian and restore wetland habitat along the creeks route.23 The work would be completed
to reduce erosion and flooding and enhance biotic resource values.24 Flooding impacts,
including any reduction in floodplain area or depth, would be reevaluated by FEMA upon
request of the Town and a Letter of Map Amendment (LOMA) issued, subject to evaluation
of the new conditions.25 The in-channel restoration work on Trout Creek work would be
conducted under permit from the relevant resource agencies (see permitting discussion in
the Biology section of this EIR, Section IV.H) so potential impacts associated with creek
alteration would be less than significant. Potential impacts to hydrology and water quality
are therefore less than significant.
The proposed project includes a policy that site design would incorporate Low Impact
Development (LID) principles including stormwater infiltration, retention and treatment on
site, consistent with NPDES, Lahontan Water Board and Town of Truckee stormwater
standards. LID uses urban design concepts which mimic natural (pre-development)
hydrologic processes by reducing the amount of impervious coverage and maintaining site
infiltration. The Railyard Draft Master Plan includes a Stormwater Management Concept
which emphasizes LID and utilizes landscaped areas to control and treat stormwater at its
source, increase infiltration and reduce runoff. The proposed project would not use local
groundwater for water supply (see Section IV.K, Utilities, for discussion of potable water
supply for the project) and therefore would not affect aquifer levels by groundwater
withdrawal. As a result, the project would not deplete groundwater supplies or interfere
substantially with groundwater recharge such that there would be a net deficit in aquifer
volume or a lowering of the local groundwater table level. These potential impacts are
therefore less-than-significant.
The Railyard Draft Master Plan includes a policy to maintain a minimum 20-foot setback for
development beyond the mapped 100-year floodplain. As a result, the project does not
propose to place housing within a 100-year flood hazard area as mapped on a federal Flood
Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map, nor
place within a 100-year flood hazard area structures which would impede or redirect flood
flows. The project would include activities with the 100-year flood hazard zone (relocation
23 Town of Truckee, 2007, Truckee Railyard Master Plan: Public Review Draft, 26 November,
2007.
24 PWA, LTD., 2003. Trout Creek Restoration Project; Design Documentation Report, 21 May.
25 Conditional LOMA. Federal flood insurance requirements apply to structures, not to
properties; however, if a structure is proposed, a property owner may submit data for a conditional
LOMA. The technical requirements are the same as for a LOMA for an existing structure; however, the
review is based on proposed conditions. Upon completion of the structure, the property owner must
still apply for a LOMA to have the Federal flood insurance requirement removed.
www.fema.gov/library/.
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of the Balloon Track and adjustment of the Trout Creek alignment, as discussed above) in
coordination with the separate Trout Creek Restoration Project. As the stated goals of both
projects include the improvement of habitat, reduction of flood hazard and protection of
the creek, this is a less-than-significant impact.
c. Significant Hydrology and Storm Drainage Impacts. Implementation of the Draft
Master Plan could result in the following significant impacts related to hydrology and water
quality.
(1) Construction-Period Impacts. Construction and grading within the Plan Area
would require temporary disturbance of surface soils. During the construction period,
grading and excavation activities would result in exposure of soil to runoff, potentially
causing erosion and entrainment of sediment (and potentially contaminants associated with
releases that may have occurred as a result of past industrial uses) in the runoff. Soil
stockpiles and excavated areas on the Plan Area would be exposed to runoff and, if not
managed properly, the runoff could cause erosion and increased sedimentation and
pollutants in stormwater.
Impact HYD-1: Construction activities could result in degradation of water quality in
the receiving waters by reducing the quality of stormwater runoff. (S)
The potential for pollutant releases is present at most construction sites given the types of
materials used, including fuels, oils, paints, and solvents. Once released, these substances
could be transported to the receiving waters in stormwater runoff, wash water, and dust
control water, potentially reducing water quality. In addition, the Plan Area is the location of
historic chemical releases that have affected soil quality. Erosion of contaminated soils
could result in the transport of pollutants (along with the sediments) to the receiving
waters.
The Basin Plan includes specific guidelines for construction projects, including prohibition
of discharge of sediments to waters listed as impaired for sediment on the Clean Water Act
(CWA) Section 303(d) list. In this case, Basin Plan requirements are generally enforced
through implementation and required compliance with applicable NPDES permits. The
NPDES Construction General Permit requires a sediment monitoring plan if the site
discharges directly to a water body listed on the 303(d) list for sediment.
Mitigation Measure HYD-1: The project proponent shall prepare a Storm Water
Pollution Prevention Plan (SWPPP) designed to reduce potential impacts to surface
water quality throughout the construction period of the project. The SWPPP must be
maintained on-site and made available to Town inspectors and/or Water Board staff
upon request. The SWPPP shall include specific and detailed Best Management
Practices (BMPs) designed to mitigate construction-related pollutants. At minimum,
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BMPs shall include practices to minimize the contact of construction materials,
equipment, and maintenance supplies (e.g., fuels, lubricants, paints, solvents, adhe-
sives) with stormwater. The SWPPP shall specify properly designed centralized storage
areas that keep these materials out of the rain.
An important component of the stormwater quality protection effort is the knowledge
of the site supervisors and workers. To educate on-site personnel and maintain
awareness of the importance of stormwater quality protection, site supervisors shall
conduct regular tailgate meetings to discuss pollution prevention. The frequency of
the meetings and required personnel attendance list shall be specified in the SWPPP.
The SWPPP shall specify a monitoring program to be implemented by the construction
site supervisor, which must include both dry and wet weather inspections. In addition,
in accordance with SWRCB Resolution No. 2001-046,26 monitoring would be required
during the construction period for pollutants that may be present in the runoff that
are “not visually detectable in runoff.”27
BMPs designed to reduce erosion of exposed soil may include, but are not limited to:
soil stabilization controls, watering for dust control, perimeter silt fences, placement
of fiber rolls, and sediment basins. The potential for erosion is generally increased if
grading is performed during the rainy season as disturbed soil can be exposed to
rainfall and storm runoff. If grading must be conducted during the rainy season, the
primary BMPs selected shall focus on erosion control; that is, keeping sediment on the
site. End-of-pipe sediment control measures (e.g., basins and traps) shall be used only
as secondary measures. If hydro-seeding is selected as the primary soil stabilization
method, then these areas shall be seeded by September 1 and irrigated as necessary
to ensure that adequate root development has occurred prior to October 1. Entry and
egress from the construction site shall be carefully controlled to minimize off-site
tracking of sediment. Vehicle and equipment wash-down facilities shall be designed to
be accessible and functional during both dry and wet conditions.
The Town of Truckee Department of Engineering shall review and approve the SWPPP
prior to approval of the grading plan. Town staff may require more stringent
stormwater treatment measures, at their discretion. Implementation of this mitigation
would reduce the level of significance of this impact to a less-than-significant level.
(LTS)
26 State Water Resources Control Board, 2001. Modification of Water Quality Order 99-08-DWQ
State Water Resources Control Board (SWRCB) National Pollutant Elimination System (NPDES) General
Permit for Storm Water Discharges Associated with Construction Activity.
27 Construction materials and compounds that are not stored in water-tight containers under a
water-tight roof or inside a building are examples of materials for which the discharger may have to
implement sampling and analysis procedures.
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(2) Operation-Period Impacts. New construction and intensified land uses at the
Plan Area would result in increased vehicle use and potential discharge of associated
pollutants. Increased numbers of vehicles and parking facilities at the Plan Area would likely
result in increased leaks of fuel, lubricants, tire wear, and fallout from exhaust, which will
contribute petroleum hydrocarbons, heavy metals, salt or deicing chemicals, and sediment
to the pollutant load in runoff and snowmelt being transported to receiving waters. Snow
storage can result in an accumulation of dirt, oil, debris, and trash in snow piles which will
result in a seasonal increase in the release of these pollutants during periods of rain and
thaw, primarily the first flush resulting from warm spring weather. Runoff from the
landscaped areas at the proposed project may contain residual pesticides and nutrients. The
Water Board’s Basin Plan makes note of deicing salt and traction sand28 in stormwater runoff
contributing to vegetation mortality (including trees) in roadside environments. This in turn
can increase erosion and sedimentation problems. Long-term degradation of runoff water
quality from the site could impact local water quality in Trout Creek and/or the Truckee
River. The Truckee River is listed as impaired for sediment on the CWA Section 303(d) list.29
Impact HYD-2: Post-construction site uses could result in degradation of water quality
in the receiving waters by reducing the quality of stormwater and snowmelt runoff. (S)
The proposed project does not specifically identify selected BMPs to treat stormwater runoff
prior to discharge to Trout Creek or the Truckee River. Untreated discharge from the site
would likely contain elevated levels of pollutants and therefore could result in a significant
impact to water quality requiring mitigation.
Mitigation Measure HYD-2: Project proponents shall have a storm water management
plan (SWMP) prepared by a qualified professional, prior to issuance of the grading
permit(s). The SWMP shall demonstrate, through detailed hydraulic analysis, that
implementation of proposed drainage plans would result in treatment of the runoff
from the site (in compliance with the Town NPDES permit). The qualified professionals
preparing the design-level SWMP shall consider additional measures designed to
mitigate potential water quality degradation of runoff from all portions of the
completed development. In general, passive, low-maintenance Best Management
Practices (BMPs) (e.g., grassy swales, porous pavements) are preferred by the Water
Board. The Town shall ensure that the project design includes features and operational
BMPs to reduce potential impacts to surface water quality associated with operation of
28 Application of road traction sand is a management practice designed to improve vehicle
traction on snow- and ice-covered roads. When traffic grinds the sand into smaller particles it can
become suspended in runoff, transported off-site and deposited into waterways, potentially impacting
aquatic life habitat.
29 Water Board, 2003, op. cit.
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the project to the maximum extent practicable. These features shall be included in the
SWMP and final development drawings.
The SWMP includes by reference Attachment 4 of WQO 2003-0005-DWQ (CAS000004),
which provide specific design standards applicable to the project based on the size
and nature of the proposed project. As specified by the MS4 General Permit, all new
development projects, regardless of size, should incorporate appropriate source
control and site design measures that minimize stormwater pollutant discharges to
the maximum extent practicable. The proposed project would be required to comply
with the terms of the SWMP and WQO Attachment 4, including (but not limited to):
Numeric Sizing Criteria for Pollutant Removal Treatment Systems. The project
must include source controls, design measures, and treatment controls to
minimize stormwater pollutant discharges. Treatment controls must be sized to
treat a specific amount – about 85 percent – of average annual runoff.
Operation and Maintenance of Treatment Measures. Treatment controls often
do not work unless adequately maintained. The permit requires an operations and
maintenance (O&M) program, which includes: 1) identifying the properties with
treatment controls; 2) developing agreements with private entities to maintain the
controls, and 3) periodic inspection, maintenance (as needed), and reporting.
Limitation on Increase of Peak Stormwater Runoff Discharge Rates.
Urbanization creates impervious surfaces that reduce the landscape’s natural
ability to absorb water and release it slowly to creeks. These impervious surfaces
increase peak flows in creeks and can cause erosion. Projects must evaluate the
potential for this to occur and provide mitigation as necessary.
As per Water Board Basin Plan implementation guidance regarding salt and traction
sand use for road and walkway maintenance, salt or traction sand shall be applied in a
careful, well-planned manner, by competent, trained crews. Should even the “proper”
application of salt be shown to cause adverse water quality impacts, the Water Board
would require that it no longer be used in environmentally sensitive areas. Should an
alternate deicer be shown to be effective, environmentally safe, and economically
feasible, its use shall be encouraged in lieu of salt. The design and implementation of
BMPs for the project shall integrate, as feasible, features that will minimize the impact
of deicing compounds and sedimentation impacts related to sanding or other ice
control methods, including considering impacts related to accumulated pollutants in
seasonal snow storage and the relatively sudden release of the accumulated materials
during periods of thaw and rain. BMPs shall be sized appropriately and operations and
maintenance schedules shall account for these seasonal differences.
The design team for the development project shall review and incorporate as many
concepts as practicable from Start at the Source, Design Guidance Manual for Storm-
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water Quality Protection30 and the California Stormwater Quality Association’s
Stormwater Best Management Practice Handbook, New Development and
Redevelopment. Any enclosed parking areas shall not be drained to the stormwater
conveyance system. The garages should be dry-swept or, if washdown water is used
the effluent should be discharged to the sanitary sewer system under permit from the
Town of Truckee.
The Town of Truckee Department of Engineering shall review and approve the SWMP
prior to approval of the grading plan. Town staff may require more stringent
stormwater treatment measures, at their discretion. Implementation of this mitigation
would reduce the level of significance of this impact to a less-than-significant level.
(LTS)
Impact HYD-3: Dewatering may contain contaminants and if not properly managed
could cause health and safety-related impacts to construction workers and the
environment. (S)
Groundwater at the Plan Area could be encountered at about 20 feet below the ground
surface (and on a seasonal basis may be present at shallower depths) and may therefore be
encountered during excavation for building foundations, utilities, and other improvements.
There are two general classes of pollutants that may result from dewatering operations;
sediment, and chemical compounds. High sediment content in dewatering discharges is
common because of the nature of the operation in which soil and water mixes in the
turbulent flow of high volume pump intakes. Chemical pollutants are most commonly found
in dewatering in areas with a history of groundwater contamination (e.g., leaks to the
subsurface from historical uses). The Plan Area has a history of industrial activity (refer to
Section IV.J, Hazards and Public Safety, of this EIR for discussion of identified areas of
potential subsurface contamination and impacts and mitigations required before site
development). Direct discharge of dewatered groundwater to the storm drainage system
could result in water quality impacts to the receiving waters.
Mitigation Measure HYD-3: The SWPPP shall include provisions for the proper
management of construction-period dewatering activities. At minimum, all dewatering
shall be contained prior to discharge to allow the sediment to settle out, and filtered,
if necessary to ensure that only sediment-free water is discharged to the storm or
sanitary sewer system, as appropriate. In areas of suspected groundwater
contamination (i.e., near sites where chemical releases are known or suspected to have
occurred), the groundwater shall be analyzed by a State-certified laboratory for the
suspected pollutants prior to discharge. Based on the results of the analytical testing,
30 Bay Area Stormwater Management Agencies Association, 1999. Start at the Source, Design
Guidance Manual for Stormwater Quality Protection.
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the project proponent shall acquire the appropriate permit(s) prior to discharge of the
dewatering effluent. Discharge of the dewatering effluent may require a permit from
the Water Board (for discharge to the storm sewer system) and/or the Town of Truckee
(for discharge to the sanitary sewer system).
Proper implementation of the mitigation measure described above would reduce this
impact to a less-than-significant level. (LTS)
Impact HYD-4: Alteration of the site drainage patterns could potentially result in
exceedance of the capacity of downstream stormwater conveyance structures, result-
ing in localized flooding. (S)
Under the existing conditions, most of the Plan Area is undeveloped pervious surfaces.
Although the details of the specific elements to be developed at the project are unknown, it
is expected that the project would result in an increase in the amount of impervious
surfaces relative to the existing conditions. The project proposes to implement Low Impact
Development (LID) design standards and participate in the Leadership in Energy and
Environmental Design Neighborhood Development (LEED-ND) Pilot Program.31 The LEED-ND
Rating System integrates the principles of smart growth, urbanism and green building into
the first national system for neighborhood design. LEED-ND certification provides
independent, third-party verification that a development's location and design meet
accepted high levels of environmentally responsible, sustainable development.32 A key
feature of LEED-ND development includes advanced stormwater management.33
Participation in these programs would encourage design decisions that should reduce
significantly the impacts of the proposed project on hydrology and water quality. However,
the specific site design, and hence the potential severity of the impact is unknown. As the
future drainage patterns (which have not yet been specified) may change so that drainage
amounts directed toward particular subareas may increase or decrease, a substantial
increase in drainage directed to a particular subarea and conveyance system may result in
exceedance of the capacity of the system. This could result in localized flooding during
extreme storm events.
Restoration of Trout Creek to a more stable and naturally-functioning creek channel corridor
upstream and within the Master Plan Area has been proposed by the Town of Truckee.
Approximately 6,000 feet of natural creek channel corridor would be restored with a
combination of channel modification and floodplain restoration. The restoration plan is a
31 Town of Truckee, 2007, Truckee Railyard Master Plan: Public Review Draft, 26 November,
2007.
32 U.S. Green Building Council, updated. LEED for Neighborhood Development: LEED Rating
Systems. accessed 2-8-08 at: www.usgbc.org/DisplayPage.aspx?CMSPageID=148.
33 U.S. Green Building Council, 2008. LEED for Neighborhood Development Pilot Draft Project
Checklist, May. Accessed 7/1/08 at: www.usgbc.org/ShowFile.aspx?DocumentID=4109.
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separate project from the proposed Master Plan project, but as the areas overlap and some
Master Plan elements (i.e., balloon track relocation, Glenshire Drive reroute, and site
grading activities) are interdependent with the restoration, the creek restoration efforts
would be coordinated with Master Plan development.34 It is anticipated that the restoration
of Trout Creek would, when completed, result in a significant reduction in flooding in the
restoration area, including the area of the proposed Master Plan project. Changes in the
100-year floodplain within the area of the Trout Creek restoration, as compared to the most
recent FIRM mapping, would be resolved by the Letter of Map Amendment (LOMA) process
with FEMA, possibly resulting in new boundaries for the 100- and 500-year flood zones.35
Mitigation Measure HYD-4: The project shall implement Low Impact Development (LID)
design standards and participate in the Leadership in Energy Environmental Design
Neighborhood Development (LEED-ND) Pilot Program, including advanced stormwater
management techniques, as feasible.
As a condition of approval of the final grading and drainage plans for the project, the
project proponent shall demonstrate through the preparation of a detailed hydraulic
analysis, to be prepared by a licensed professional, that implementation of the
proposed drainage plans would not increase total off-site peak flow rates, or exceed
the capacities of local system components or if redirected drainage would exceed the
capacity of downstream components, that the project would construct improvements
and/or increase the conveyance capacity of these undersized components. The project
must use drainage components that are designed in compliance with Town of Truckee
standards. The grading and drainage plans shall be reviewed for compliance with
these requirements by the Town of Truckee Planning, Building, and Engineering
Departments. Any improvements deemed necessary by the Town will be part of the
conditions of approval.
Implementation of this mitigation measure would reduce potential impacts associated
with increased peak runoff volumes to a less-than-significant level. (LTS)
Impact HYD-5: Existing water supply wells present the potential for migration of urban
pollutants to the aquifer. (S)
The Plan Area has a long history of use, and groundwater is relatively shallow at the site. No
abandoned water supply wells are known to exist on the site; however, it is possible that
‘forgotten’ wells may exist within the Plan Area. If a well was not fitted with an effective
sanitary seal when constructed, or if the seal has been damaged since installation or were to
34 Town of Truckee, 2007, Truckee Railyard Master Plan: Public Review Draft, 26 November,
2007.
35 Town of Truckee, 2006. Request for Proposals, Trout Creek Restoration Project, 12 October.
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be damaged during grading and construction of the project, surface water (potentially
containing pollutants) could seep into the well(s) and the underlying aquifer, causing water
quality degradation.
Mitigation Measure HYD-5: During the Railyard Draft Master Plan development
process, any existing water supply well within the proposed Plan Area shall either be:
HYD-5a: Inspected by a qualified professional to determine whether the well is
properly sealed at the surface to prevent infiltration of water-borne pollutants into
the well casing or surrounding gravel pack. The California Well Standards require
an annular (ring-shaped) surface seal of at least 20 feet. If the wells are found not
to comply with this requirement, the project sponsor shall retain a qualified well
driller to install the required seal. Documentation of the inspections and seal
installations, if any, shall be provided to the Town prior to final approval of any
future grading plans; or
HYD-5b: Properly abandoned in compliance with the California Department of
Water Resources, California Well Standards, and Nevada County Community
Development Agency, Environmental Health Department prior to final approval of
the grading plan.
Implementation of one of the above mitigation measures would reduce this impact
to a less-than-significant level. (LTS)