Chapter 9
NOISE
9-1.
INTRODUCTION
This chapter presents a description of the existing conditions in the Shorezone area with
respect to noise and identifies the potential environmental impacts of noise that could
result from each of the five alternatives. There are many sources of noise in the Tahoe
Region. Traffic on highways in the Region generates “noise corridors” along its path.
During the winter months, tire chains on vehicles generate more noise than non-chain
equipped vehicles. Aircraft noise, though intermittent, is loud and widely broadcast.
Other adverse sources of noise include pets, machinery associated with refuse
collection, stereo systems, construction, timber cutting, off-road vehicles, industrial
operations, and motorized watercraft.
Average noise levels describe the general acceptability of a noise environment, but it is
usually a specific noise source that annoys people. A number of factors other than the
level of noise may contribute to impacts perceived by visitors or residents of the Region.
These include the duration of the noise, the presence of pure tone components, the
presence of impulses, the time of day, the activity being interfered with, prior attitudes of
the recipient toward the noise generator, and the level of background noise in the area.
The level of noise at a specific site within a community is a random value that is
continually changing as an activity, or level of activity, continually changes. The sound
level is controlled by the activity that occurs at the site. The level of acceptability of a
noise at a particular site is a function of the compatibility of the activity that generated the
noise to the other activities in the area. In addition, acceptability of a specific level of
noise may vary with the time of day.
Tolerance to noise in the Shorezone is dependent, in part, upon the type of a
recreational experience the visitor expects. For example, a person using motorized
watercraft may be more tolerant of noise generated by other motorized watercraft.
However, individuals seeking solitude or quiet refuge at a beach are likely to be less
tolerant of motorized noise. The various levels of tolerance individuals have toward
specific noises are evidenced by the significant number of noise complaints received by
TRPA concerning the operation of personal watercraft and other motorized watercraft on
Lake Tahoe.
REGULATORY CONSIDERATIONS
The Tahoe Regional Planning Agency (TRPA)
TRPA has adopted standards for noise, including single event standards for aircraft and
other motorized vehicles and cumulative noise events (called Community Noise
Equivalent Levels or CNELs), which apply to the average noise level over a 24-hour
period. The standards, established in the Goals and Policies, apply to the entire Lake
Tahoe Region. More details are provided later in this chapter.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 1
Federal Agencies
The Federal Noise Control Act of 1972 (42 USC § 4901 et seq. [1994]) established a
requirement that all federal agencies must comply with applicable federal, state,
interstate, and local noise control regulations. Federal agencies also are directed to
administer their programs in a manner that promotes an environment free from noise
that jeopardizes public health or welfare.
State Agencies
The California Department of Health Services
The CA DHS has published guidelines for the noise element of local general plans
(1987). These guidelines include a noise level/land use compatibility chart that
categorizes outdoor Community Noise Equivalent Levels into four compatibility
categories of normally acceptable, conditionally acceptable, normally unacceptable, and
clearly unacceptable, depending on land use. The chart in the state noise element
guidelines identifies normally acceptable noise levels for low-density residential uses as
CNEL values below 60 dB. The normally acceptable range for high-density residential
uses is identified as CNEL values below 65 dB.
9-2.
EXISTING NOISE CONDITIONS AND TRENDS
EXISTING CONDITIONS
Long-term noise monitoring in the Region occurs at five-year intervals during the
threshold evaluation process. The 2001 Threshold Evaluation Report concluded that the
primary noise sources in the Region, including the two Shorezone areas monitored, are
traffic noise and human activity, and that traffic is expected to continue to increase.
TRPA expects improved compliance with the adopted 600-foot no-wake zone to reduce
lakezone noise sources that irritates people.
Table 9-1 shows TRPA’s current noise threshold standards:
Table 9-1. TRPA Noise Threshold Standards
Single Noise Event
Boats (not to exceed any of 3 tests)
Motor Vehicles
(less than 6,000 lbs GVW)
Motor Vehicles
(greater than 6,000 lbs GVW)
Motorcycles
Off-road Vehicles
Snowmobiles
Noise Measurement
§ 82 dBA measured at 50 feet with engine at 3,000 rpm.
§ SAE test J1970 or SAEJ1970, Shoreline Test, 75 dBA
(standard adopted 7/03)
§ SAE test J2005, Stationary Test, 88 dBA if watercraft
manufactured on or after 1/1/93 and 90 dBA if watercraft
manufactured before 1/1/93 (standard adopted 7/03)
76 dBA running at <35/mph (82 dBA running at >35/mph)
measured at 50 feet
82 dBA running at <35/mph (86 dBA running at >35/mph)
measured at 50 feet.
77 dBA running at <35/mph (86 dBA running at >35/mph)
measured at 50 feet.
72 dBA running at <35/mph (86 dBA running at >35/mph)
measured at 50 feet.
82 dBA running at <35/mph measured at 50 feet.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 2
Table 9-1. TRPA Noise Threshold Standards
Single Noise Event
Noise Measurement
Community Noise Equivalent Levels: Background levels shall not exceed the following:
Industrial
65 dB CNEL
High density residential
55 dB CNEL
Low density residential
50 dB CNEL
Hotel/motel facilities
55 dB CNEL
Commercial areas
65 dB CNEL
Urban outdoor recreation
55 dB CNEL
Rural outdoor recreation
50 dB CNEL
Wilderness and roadless
45 dB CNEL
1
Transportation
(2)
U.S. 50
65 dB CNEL
(2)
SR 89, 207, 28, 267, and 431
55 dB CNEL
(3)
South Lake Tahoe Airport
60 dB CNEL
1
CNEL values for transportation corridor.
This threshold overrides the land use CNEL thresholds and is limited to an area within 300 feet from the
edge of the road.
3
This threshold applies to those areas impacted by the approved flight paths.
2
Table 9-2 below summarizes the 2001 threshold conditions and attainment status.
Table 9-2. Noise Threshold Status
Threshold
2001 Threshold Status
2001 Attainment Status
Limited data available. USFS issues citations for
snowmobiles, which exceeded single event
standards in the winter of 2000-2001.
TRPA sampled community noise at 7 near
Shorezone locations. Three locations exceeded
applicable CNEL standards.
CNEL measurements are extremely limited; thus
conclusions have minimal support. TRPA has
contracted with Brown Buntin Associates to
conduct extensive monitoring. Study is in progress.
Source: TRPA Threshold Evaluation 2001.
Non-Attainment
Single Noise Events
Airport Noise
Other
Community Noise
Equivalent Levels
(CNEL)
Non-attainment.
The 2001 Threshold Evaluation Report recommended the following specific actions with
relevance to the following noise issues.
§
§
TRPA should undertake a long-term single-event noise-monitoring program for
the noise generators listed in the threshold. This program would include
watercraft as part of an ongoing, consistent noise-monitoring program.
TRPA should continue to implement the noise control measures in place, and
should add three supplemental measures to the Regional Plan: hire a noise
compliance officer for the Region to determine compliance with all noise
thresholds; develop and implement strategies to reduce traffic-related noise on
roadways; and revise the exemption for construction noise to reduce impacts
from these activities (which, in some cases last years, and can be a significant
problem).
§
TRPA should adopt the noise measurement protocols listed in the Nevada
Administrative Code (NAC) 488.460 for watercraft. Such enforcement methods
make monitoring safer to perform and provide more defensible results.
§
TRPA shall study the effects of noise on wildlife, and based on such studies,
develop appropriate standards for wilderness areas to protect wildlife.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 3
Single Event Noise Level (SENL)
In 1997, TRPA adopted a 600-foot no-wake zone to maintain noise levels on shore that
allow normal voice conversation. Within this zone, boats are to be operated at such a
speed as to not create a wake (on average, approximately 5 mile per hour), a level at
which noise production is greatly reduced for most engine types. In recent years the
States of Nevada and California, El Dorado County, and the City of South Lake Tahoe
have passed laws and implementing ordinances to address noise enforcement and
provide consistency and defensibility in noise testing protocols. In 2003 TRPA adopted
an ordinance change for motorized watercraft that provides consistency with the other
jurisdictions and measurements and maintenance of TRPA’s boat noise standards. This
amendment to the Code of Ordinances was prompted by public concern over noise
emitted from watercraft, and based on a petition from lakefront property owners and
numerous other public complaints received by TRPA over the past several years.
As mentioned above, in July 2003 TRPA amended the Noise Threshold Single Event
standards and associated Code language to add a shoreline noise test based on SAEJ1970, and a stationary test procedure based on SAE-J2005. These test procedures
were developed by the SAE to provide more practical enforcement of boat noise
standards, and are intended to be consistent with the results obtained using the 50-foot
pass by noise measurement according to SAE-J34 (the basis for the Threshold value).
The States of Nevada and California have adopted these standards.
Therefore, as of September 2003, watercraft operating on Lake Tahoe must not fail any
of the following separate noise threshold measurement standards:
The Pass-by Test (Original TRPA Standard)
This test, as described in the Code Chapter 23, Noise Limitations, provides for a test
developed by the Society of Automotive Engineers (SAE). This test, (SAE-J34) uses a
method in which a boat must pass by the sound meter, with the engine at 3,000
revolutions per minute (rpm) and at a distance of 50 feet, and meet the 82 dBA standard.
This test was designed for marine engineers, and not intended as an enforcement tool.
The problems associated with this test are that the rpm must be exactly 3,000 and the
distance must be exactly 50 feet. The problems associated with the pass-by test and the
fact it was designed for engineers in controlled situations makes the transition to
enforcement difficult (TRPA 2003b).
The Shoreline Test (Adopted July 2003)
This test was designed for enforcement purposes by SAE to monitor marine craft under
conditions of actual boat usage. This test does not require a special course to set up or
have associated delays, and can be performed from shore, dock, or platform. The
shoreline test is most effective from the shoreline where virtually all noise complaints
originate. It is effective in the enforcement of noise standards applicable to all types of
watercraft. The test allows for watercraft to emit up to 75 decibels on the schedule A [dB
(A)], measured as specified in the SAE Standards. This level remains the same
regardless of the distance from the watercraft to the shoreline (TRPA 2003b).
The Stationary Test (Adopted July 2003)
This test was also designed for enforcement purposes. This test requires no special
course set up or associated delays. The stationary test can be performed on the spot
and measures the exhaust noise, which is the main source of noise. This establishes a
measurable muffler dB(A). The test allows for watercraft to emit up to 88 dB(A) if
manufactured on or after January 1, 1993 and 90 dB(A) if manufactured before January
1, 1993. The stationary test is implemented as specified in the SAE Standards. The
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 4
decibel level is measured 1 meter behind the exhaust side of the boat and four to five
feet above the water (TRPA 2003b).
TRPA maintains no Single Event Noise Level standard for Lake areas associated with
piers, buoys, boat ramps or floating platforms. The watercraft standards listed above
apply to the boats that use these facilities. TRPA’s Plan Area Statements (PAS) assign
CNEL standards to the Shorezone and lakezone area, where applicable.
Near the end of the 1998 boating season TRPA began a public education campaign
about boat noise that continues today. Currently, education efforts include patrolling the
lake and educating first time offenders and issuing a written warning. TRPA maintains a
database of offenders and upon a second offense the violator receives a fine.
Recent monitoring (Summer 2002) conducted by Brown Buntin Associates as part of a
contract with TRPA for the 2007 Threshold Update included measurements from the
shoreline to evaluate the effectiveness of the adopted 600-foot no-wake zone.
Measurements include values for the Lmax (i.e., the maximum sound level recorded
during a noise event) and the PSIL (Personal Speech Interference Level, which is based
on the voice effort required to carry on a conversation at varying distances, dependent
upon the background noise level). The PSIL values were critical to justifying TRPA’s
adoption of the 600-foot no-wake zone. The results are shown in Table 9-3 (BBA 2004).
Table 9-3. Measured Boat Noise Levels At Shoreline with All Boats At or
Beyond No-Wake Zone
Date
Location
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
King’s Beach
8/23/02
Zephyr Cove
8/24/02
Homewood
8/24/02
Homewood
8/24/02
Homewood
8/24/02
Homewood
8/24/02
Homewood
8/24/02
Homewood
8/24/02
Homewood
8/24/02
Homewood
Source: Brown-Buntin Associates, 2004
Lmax, dBA
PSIL, dB
65.9
67.3
63.7
57.0
68.6
59.3
50.8
57.3
57.3
58.0
55.1
56.7
61.2
62.7
59.2
60.4
71.9
66.2
72.2
42.4
61.8
46.8
47.9
55.3
45.0
42.0
40.6
48.9
45.1
48.1
48.3
49.3
48.6
49.8
51.3
58.9
56.1
60.6
Description
Inboard
Inboard
Mastercraft Inboard
Chris Craft
Dual Outboard
Inboard at 1800 feet
Jet ski
Inboard
Outboard
Inboard
Inboard
Inboard
Inboard
Mercruiser I/O
Mercruiser I/O
350 Chevy I/O
Dual 502 c.i.
Dual 502 c.i.
Dual
The data reveals that the PSIL values associated with most of the observed boat
operations were consistent with TRPA’s objective of 54 dB PSIL. The exceptions were
one dual-engine outboard, and two inboard-engine boats, one fitted with dual modified
engines. Therefore, the data indicates that the 600-foot no-wake zone is effective in
reducing the potential for speech interference and consequent annoyance at the
shoreline for most watercraft (BBA 2004).
BBA conducted additional boat noise measurements in 2002 to determine whether boats
operating on Lake Tahoe normally exceeded the threshold standards. The results of
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 5
these noise measurements are listed in Table 9-4. The data indicates that, of the 42
boats observed, the noise levels produced by 15 boats were estimated to exceed the
Threshold value of 82 dBA at 50 feet. The visual procedures used to estimate the
distances to the boats were inherently inaccurate, so it is likely that the actual rate of
compliance was different from that estimated here. In addition, the method of estimating
the noise level at 50 feet did not account for reinforcement of sound due to reflections
from the surface of the water. However, the data does indicate that the noise levels
produced by some of the boats observed operating on Lake Tahoe may exceed the
Threshold value of 82 dBA at 50 feet (BBA 2004).
Table 9-4. Measured Boat Noise Levels And Estimated Noise Levels at 50 feet
Eagle Point (August 23, 2002)
Boat
Type
Lmax,
dBA
Estimated
Distance to Boat
Ski
69
1000
Inboard
77
300
Inboard
74
300
Inboard
75
250
Inboard
72
300
Inboard
75
200
Inboard
66
500
Inboard
69
300
Inboard
72
200
Inboard
72
200
Inboard
64
500
Inboard
70
250
Inboard
68
300
Inboard
69
250
Inboard
67
300
Inboard
62
500
Inboard
68
250
Paddle
68
250
Inboard
66
300
Paddle
61
500
Inboard
65
300
Paddle
65
300
Inboard
68
200
Inboard
66
250
Inboard
64
250
Inboard
64
250
Inboard
64
200
Inboard
64
200
Inboard
63
200
Outboard
62
200
Inboard
62
200
Inboard
62
200
Inboard
61
200
PWC
63
150
Inboard
60
200
Inboard
60
200
PWC
58
200
Inboard
55
250
Inboard
56
200
Inboard
56
200
Inboard
56
200
Inboard
54
200
Source: Brown-Buntin Associates, 2004
Estimated Lmax at
50 feet, dBA
Does Estimated Lmax at 50
feet exceed 82 dBA?
95
93
90
89
88
87
86
85
84
84
84
84
84
83
83
82
82
82
82
81
81
81
80
80
78
78
76
76
75
74
74
74
73
73
72
72
70
69
68
68
68
66
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 6
The data collected by BBA in 2002 indicated that noise produced by all of the observed
boats complied with the shoreline noise standard of 75 dBA. The data shown in Table 94 indicated that noise produced by all but one of the observed boats complied with that
standard. However, the noise levels of 15 of the 42 observed boats in Table 9-4 may
have exceeded 82 dBA, when extrapolated to a distance of 50 feet. As noted above, the
methods used to estimate the noise level at this distance were less than definitive,
depending on visual estimates and simplified extrapolation assumptions. Nonetheless, it
appears that the shoreline noise testing procedure will provide a useful mechanism to
identify the boats most likely to cause annoyance and speech interference (BBA 2004).
Community Noise Equivalent Level
Another measurement standard used for noise is the Community Noise Equivalent Level
(CNEL). This measurement standard uses measurements taken over a 24-hour period.
The average is calculated by using the single number representing the sound levels for
the entire 24-hour period with weighted factors incorporated to penalize sounds that
occur during evening and nighttime hours, to account for increased sensitivity to noise
during those hours. The weighted factors include an addition of 4.77 dBA to
measurements between 7 PM and 10 PM and 10 dBA between 10 PM and 7 AM. CNEL
standards have been established for each Plan Area Statement based on land use. The
CNEL standards set an acceptable noise level in the respective plan areas, and are
generally based on the compatibility of the activity that generated the noise with the
remaining activities in the area. TRPA uses CNEL standards as a regulatory tool,
although critics believe this measurement system is not sensitive enough to capture
daytime activities that create perceived unacceptable noise. Table 9-1 contains the
maximum noise levels for the land use categories in the PAS.
In 2000, Bollard & Brennan, Inc completed a noise monitoring survey to evaluate the
existing noise environment throughout the Tahoe Region. The results were incorporated
into the 2001 Threshold Evaluation Report. Bollard & Brennan performed continuous,
24-hour sound level measurements at 43 sites, 7 of which lie in or near the Shorezone
(Table 9-5). In three cases the measured CNEL exceeded the applicable PAS standard
based on use type. However, measurements were very limited (one day or less at each
location – refer to the 2001 TRPA Threshold Evaluation (July 2002) for details), so
conclusions are difficult to make and/or support.
Table 9-5. Comparison of Measured Noise Levels to Plan Area Statement Criteria
Monitoring
Site
PAS #
PAS
Description
39S
146
47
055
Emerald Bay
East Shore
(Sand Harbor)
23S
066
Zephyr Cove
Land Use
District
Rural
Recreation
PAS CNEL
Criteria, dB
50
54.1
51.0
Recreation
Urban Outdoor
Recreation
55
N/A
57.4
55
51.0
56.7
Measured CNEL, dB
Source: 2001 Threshold Evaluation Report.
CNEL noise monitoring has also been performed for several Shorezone areas related to
specific Shorezone site proposals. Some of these locations include the Tahoe City
Marina, Sierra Boat Company, Lakeland Village, and Timber Cove Marina. Monitoring in
these areas occurred in conjunction with proposed projects or community plans. All
these projects lie in commercial plan areas that permit 65 CNEL in the upland area and
55 CNEL in the Shorezone. The results are shown below.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 7
§
Tahoe City Marina (1989)
58.0 CNEL
§
Sierra Boat Company (1992)
58.4 CNEL
§
Lakeland Village (1992)
53.8 CNEL
§
Timber Cove (1993)
56.3 CNEL
9-3.
SUMMARY OF PROJECT ALTERNATIVES
As discussed in Chapter 2 of this EIS, the different alternatives would have varied effects
on Shorezone development at Lake Tahoe.
ALTERNATIVE 1 – NO PROJECT ALTERNATIVE
This alternative would continue current practices for the review of Shorezone projects
under the existing TRPA Code of Ordinances.
ALTERNATIVE 2 – PROPOSED PROJECT ALTERNATIVE
This alternative would result in revisions to the Shorezone provisions of the Code of
Ordinances based on the consensus agreements of the Shorezone Partnership Group,
direction from the Shorezone Policy Committee, and TRPA staff revisions for
consistency, streamlining, and environmental adequacy. The general goal of this
proposal is to assure all littoral parcels are eligible to apply for a pier and sufficient buoys
to access the lakes of the Region; that all related impacts would be mitigated; and that
all applicable environmental thresholds would be attained. The prohibition on the
location of Shorezone structures in prime fish habitat would be eliminated under this
alternative. This alternative would also include a new scenic review system and would
introduce the concept of private, quasi-public, and public structures to provide the basis
for design standards and deviation from those standards.
ALTERNATIVE 3 – NO FISH HABITAT ALTERNATIVE
This alternative would continue all Shorezone provisions of the current TRPA Code,
except that the prohibitions on Shorezone structures located in fish habitat areas would
be eliminated, including stream setbacks. In addition, this alternative would allow littoral
parcel owners, who also have the availability of a multiple-use facility, to apply for their
own private Shorezone structure.
ALTERNATIVE 4 – PUBLIC STRUCTURES ONLY ALTERNATIVE
This alternative would remove the prohibition on locating Shorezone structures in prime
fish habitat. The prohibition of Shorezone structures within 200 feet of a stream mouth
would remain unchanged. However, in order to promote thresholds, this alternative
allows new or expanded structures for public facilities (open to the general public) only.
No new or expanded private structures are allowed.
ALTERNATIVE 5 – REDUCED DEVELOPMENT ALTERNATIVE
This alternative would prohibit the construction of private single-use Shorezone
structures. Under this alternative, only multiple use structures would be permitted and
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 8
would require a 2:1 structure reduction mitigation for private multiple use and
quasi-public structures, and a 1:1 structure reduction mitigation for public multiple use
structures.
Table 9.6 below provides a summary of the main project features of the five proposed
alternatives and provides an abbreviated overview of their differences. Table 9.7
provides a summary of the overall total buildout numbers for the five alternatives.
Table 9-6. Summary of Project Alternatives
Project Features
Streamlined
Review
New Structures
Private
Structures
Quasi–Public
Structures
Public Structures
Repairs/
Modifications
Reduction in
Structures
Alternative 1
No Project
Alternative 2
Proposed
Project
Alternative 3
No Fish
Habitat
Restrictions
Alternative 4
Public
Structures Only
Alternative 5
Reduced
Development
No
Yes
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Public Use
Only
No
Multi Use
Only
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Public Use
Only
No
No
No
Yes
No
Yes
Table 9-7. Full Buildout Numbers by Alternative
Structure Type
Piers
Buoys
Ramps
Floating Docks
Slips
Alternative
1
839*
5,826
128*
174
3,019
Alternative
2
1,196*
8,110
72*
83
3,019
Alternative
3
1,399*
10,462
706*
1,256
3,019
Alternative
4
788*
6,517
50*
22
2,899
Alternative 5
(2:1 Reduction)
733
4,283
37
18
2,745
Source: TRPA 2004.
*Totals do not include new extensions/expansions.
9-4.
STANDARDS OF SIGNIFICANCE
The TRPA is required by the Compact to regulate activities within the Tahoe Region that
may substantially impact the environment. More specifically, TRPA must attain and
maintain noise thresholds. There are also guidelines established by county
governments, state agencies, and federal agencies, relating to noise levels in the
Region. The TRPA standards (Table 9-1) are either equal to, or stricter than these
guidelines. Some exemptions exist for construction, public safety, and fireworks.
A relatively low noise level is an attribute of the Tahoe Region that is enjoyed by both
visitors and residents. However, the Report for the Establishment of Environmental
Threshold Carrying Capacities (TRPA, 1982) indicated that background noise in the
Region is increasing as a result of escalating levels of human activity. The TRPA noise
thresholds are based on achieving the following objectives as they relate to noise:
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 9
§
Reduce or eliminate those activities in the Region that produce damaging or
distressing noise levels; and
§
Provide for community and neighborhood tranquility.
The 1982 Threshold Study Report divided noise into four components: the
characteristics of sound and noise, the sources that produce noise, people's perception
of noise, and noise impacts on wildlife.
SUMMARY OF POTENTIAL NOISE IMPACTS
Each of the five alternatives would have impacts on noise levels in the Basin, ranging in
severity and location. Potentially significant impacts to noise include the following:
1)
Increased noise from boating activity resulting from the increase in the number of
Shorezone structures. Significance will be determined based on current
attainment status of the location’s CNEL standard, current noise levels and
expected increases associated with proposed structures, and/or sensitivity of
certain areas (see description below).
2)
Increased noise from vehicle traffic accessing public facilities.
3)
Disturbance to wildlife from increased boating activity and increased public
access.
TRPA determines significance based on the specific situation of an area.
Single Event Noise Thresholds
To reduce or eliminate activities in the Region that produce damaging or distressing
noise levels, TRPA adopted maximum allowable noise levels (dBA) for a variety of single
events. The noise standards that apply specifically to watercraft are the 82.0 dBA
(measured at 50 feet with the engine operating at 3,000 RPM), the SAE-J1970 and the
SAE-J2005 standards for marine craft. These standard applies to all marine craft ranging
from personal watercraft to large tour boats.
Community Noise Equivalent Level Thresholds
Providing for community and neighborhood tranquility involves measuring the cumulative
impact of repeated noise events. The CNEL method was selected for developing
cumulative noise thresholds within the Region. This method was selected because it
provides for a slightly greater sensitivity to noise in the evening and at night. Various
maximum CNELs were selected to ensure land use compatibility with respect to noise.
Although TRPA has not established a specific land use category for the Shorezone or
the lakezone, these areas are considered as rural outdoor recreation areas with a
maximum CNEL of 50. Because commercial, residential, and tourist accommodation
uses are not permitted in the Shorezone, the CNEL used for the Shorezone is either the
level for an urban outdoor recreation area or a rural outdoor recreation area. The nature
of the upland land use pattern determines whether urban or rural outdoor recreation
standards are appropriate. For example, primarily commercial, residential, or tourist uses
in the upland results in reliance on a 55 CNEL standard. Where the upland area is
predominantly undeveloped or is used for dispersed recreation, it is designated rural
outdoor recreation and a standard of 50 CNEL or less is applied.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 10
Human perception is important for single event noise evaluation. Figure 9-1 shows
examples of different noise levels and Table 9-8 demonstrates human reaction to
changes in noise levels. The evaluation of an alternative’s potential impacts is based on
existing or proposed land uses in the Shorezone area and the relative noise levels.
Table 9-8. Subjective Reaction to Changes in Noise Levels of Similar Sources
Change in
Level dB
1
3
6
10
Subjective Reaction
Imperceptible (Except for Tones)
Just Barely Perceptible
Clearly Noticeable
About Twice (or Half) as Loud
Factor Change in Acoustical Energy
1.3
2.0
4.0
10.0
Source: Architectural Acoustics, M. David Egan, 1988.
To evaluate noise impacts and recommend mitigation measures, the analysis in this
DEIS focused on piers, public ramps and buoys, and associated watercraft noise. To
determine potential impacts, the DEIS assumes a link between the number of watercraft
facilities (e.g., piers, ramps), and the resulting noise level from associated watercraft.
Where additional noise levels are listed as significant, such determination is based on
the level of increase in sources, and not always related to thresholds. Based on the
information below, this analysis determines significance based on a doubling of noise
energy.
Noise energy and noise level are not the same measurement. Noise energy refers to the
sources of the noise, while the noise level is the measurement of loudness. For
example, if one car is blowing its horn and a second car joins in, this results in a
doubling of the sound energy. However, the sound level does not double. Instead, a
doubling of noise energy results in a three-decibel (3 dBA) increase in the measured
noise level (when the additional source is the same as the original). Therefore, using the
car horn example, the addition of the second car blowing its horn would result in an
increase of 3 dBA over the sound level generated by the first car alone.
In areas that are in attainment of their CNEL standard, TRPA staff uses a doubling of
sound energy (3 dBA) as a measure of significance, which is consistent with common
noise analysis practices according to Brown-Buntin Associates, Inc. When areas are
currently in non-attainment of the applicable CNEL standard, any increase in noise is
considered to be significant.
TRPA regulates and evaluates noise using two standards, SENL and CNEL. As
discussed previously, noise associated with boating activity, particularly personal
watercraft (PWC), has received much attention and debate over the last several years.
Noise monitoring conducted for PWC found these craft to be within the SENL standard
(1997). The TRPA single event noise threshold for boats is 82 dBA at 50 feet and 3,000
rpm. Noise monitoring of motorized watercraft conducted by Brown Buntin in 1997
indicated SENLs (at 50 feet and 3,000 rpm) associated with motorized watercraft were
measured between 66.5 and 79.5 dBA (Brown Buntin, 1997). This test identified noise
within the standard limits when the engines ran at 3,000 rpm, and considerably higher
noise levels when running full throttle.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 11
NOISE SOURCE
SOUND LEVEL
Amplified Rock and Roll
SUBJECTIVE
DESCRIPTION
120 dB
DEAFENING
Jet Takeoff @ 200 Ft.
100 dB
VERY LOUD
Busy Urban Street
80 dB
Freeway Traffic @ 50 Ft.
Conversation @ 6 Ft.
LOUD
60 dB
Typical Office Interior
Soft Radio Music
MODERATE
40 dB
FAINT
Residential Interior
Whisper @ 6 Ft.
20 dB
Human Breathing
VERY FAINT
0 dB
Figure 9.1
Examples of Sound Levels
Lake Tahoe Shorezone Ordinance Amendments DEIS
As described in Chapter 15, Public Health and Safety, PWC are often operated at high
speeds (i.e. full throttle) with sudden bursts of acceleration. Actual operating conditions
for PWC, therefore, produce higher actual noise levels and noise levels that change
dramatically and rapidly. This explains the significant number of noise complaints TRPA
receives concerning operation of jet-skis and similar watercraft on Lake Tahoe. It may be
that the 82 dBA is not an adequate numerical standard for this type of watercraft.
However, because of the two-stroke carbureted engine ban, trends in PWC motor types
have had a positive impact on noise. This is due to the quieter technology used by
engines that are fuel-injected and/or four-stroke.
As discussed previously, TRPA used a Personal Speech Interference Level (PSIL)
developed based on information from Brown Buntin, Inc., to establish acceptable
background noise levels. The desirable level allows two people standing five feet apart
to maintain a certain voice level when carrying on a conversation. TRPA adopted the
600-foot no wake zone, to maintain these noise levels. The PSIL addresses the fact that
noise from boats can be disturbing to normal activities, even though the boats may meet
TRPA’s noise standards.
Lake Tahoe ONRW Boat Sticker Mitigation Program
Several lakes and other water bodies around the country use local sticker programs for
watercraft to fund environmental protection, mitigation, enforcement, and public outreach
programs. Lake George in New York is one example where such a local registration
sticker is required for mooring, launching or operation of motorized or large nonmotorized watercraft, with annual fees from $30.00 - $37.50 or more depending on the
size of the boat. Other lakes use a differential fee ($10 - $20) depending on watercraft
registration in or out-of state. Current stickers must be prominently displayed on the
watercraft to avoid violation. The proposed Lake Tahoe sticker could be used to fund
and facilitate boating education and outreach, emissions mitigation and monitoring,
perhaps tuning requirements for emission reductions (although this would require a more
specific certification, or tuning certificate from a qualified local mechanic), enforcement
for a variety of boating issues and noise standards, and with some limited boat
inspection facilitate many of the mitigation measures discussed under the alternatives
below (e.g. boat and trailer washing before launch, and checking for aquatic weeds,
noise measurements). The support of local jurisdictions, and likely state law(s), would be
required to reap the full benefit of this program and provide financial support to local and
other enforcement entities from the program. As part of the sticker program, all
watercraft intending to operate on the lake will be required to provide certification from
an appropriate location (may include manufacturer/retailer of new boats or certified
mechanic) that noise emissions from the watercraft meet all three tests in TRPA’s single
event–watercraft standards and indicators. If such certification is not available, then it
must be obtained from an approved facility before a sticker is granted.
Long-term Monitoring Program for on Lake and near- and on-shore noise
The unique characteristics of the Tahoe Region support an expectation of lower noise
than other areas outside of the Region. Residents and visitors alike enjoy the special
outdoor experiences available here. Therefore, TRPA has adopted noise standards and
indicators to protect the reduced noise levels in the Basin.
As discussed above, watercraft are a significant source of noise in the Basin. Although
most boats meet the single event standards, some models and/or models with modified
mufflers exceed the current standards, and have resulted in many complaints from
beach goers trying to enjoy the shoreline. Boat noise can also result in exceedances of
the CNEL standards for an area, especially in areas of concentrated boat use. To
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 13
monitor the impacts of boat noise and to protect the unique outdoor experience offered
by Lake Tahoe, a long-term monitoring program will be needed to support the noise
standards that are affected by increases in shoreline and on-lake activities.
The monitoring program will be funded through the Tahoe ONRW sticker program
discussed above and other Shorezone mitigation fees. It will include, but not be limited
to, the following:
The Noise Working Group will review existing data and assist in program development,
including site selection, frequency and types of measurements (e.g. single event,
CNEL). A monitoring program will be implemented based on the input from the Group,
which includes noise experts and agency personnel who deal with noise-generating
activities in the Basin. The monitoring program will be reviewed and approved by a noise
expert prior to implementation.
Short-term measurements will be taken in areas where an increase in shoreline
structures is expected to result in an increase of 5 or more boats. Measurements will
include CNEL monitoring prior to the addition of the structures and expert-generated
noise analyses that will review and determine the increases in noise expected from the
increase in structures.
9-5.
POTENTIAL NOISE IMPACTS
MITIGATION MEASURES
AND
REQUIRED
ALTERNATIVE 1 – NO PROJECT ALTERNATIVE
This alternative would continue current practices for the review of Shorezone projects
under the existing Code.
The evaluation criteria described above provide the basis for determining the
significance of impacts to noise levels. The following impacts have been determined to
be significant when evaluated against the specific criteria described. The references to
grid units correspond with the figures in Chapter 2 associated with each alternative.
Increased Boat Usage
The increase in structures allowed by this alternative would provide for an increase in
boat usage. This increase in boat usage would increase noise levels associated with
boating. As shown below, the increase in noise levels may not violate any of TRPA’s
noise thresholds, but may bring noise levels in certain areas to irritable levels. The
proposed increase in public structures would increase noise levels associated with
activities within the Shorezone, including vehicle traffic associated with the public
facilities.
There would be several areas around the Basin where development would at least
double. Of the 203 grid units of 2,000-feet that make up the Shorezone of Lake Tahoe,
Shorezone structures would at least double in approximately 24 units as a result of full
implementation of Alternative 1. In many of these units, the increase would be much
higher than a doubling, so the noise impacts associated with the increases would be
higher than the 3 dBA. It should be pointed out that analyzing purely the number of
structures by alternative does not give a perfect comparison. The number of structures
does not correspond proportionally to the boating trips in each alternative.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 14
Some of the impact sites also correspond with certain wildlife zones. This creates
additional potential impacts to wildlife in these areas. Noise impacts associated with
increased boating at Emerald Bay conflict with Bald Eagle management sites. Boating
increases create noise impacts in Waterbird Habitat Management zones at Emerald Bay
and Rabe Meadow near Stateline on South Shore. Osprey nesting sites could also be
impacted within Emerald Bay, and possibly around the Glenbrook area. For additional
discussion of impacts to wildlife, see Chapter 12.
Vehicles Accessing Public Facilities
In addition to increased noise from motorized watercraft, implementation of this
alternative results in some motor vehicle noise from people accessing new public
structures. Activity in parking lots increases local noise. Under this alternative, the
existing number of public structures could potentially double, as would associate noise
energy at these locations. The noise impacts from these structures will be evaluated at
the project-review level. Required mitigation may include a reduction in the proposed
project size, limitations on daily use associated with increased motor vehicles, or other
appropriate measures. Such mitigation will be a condition of permit approval.
Significant Noise Impacts
9.1.1 Impact: The No Project Alternative would result in an increase in noise from
boating activity.
As stated above, TRPA determines significance based on the specific noise status of an
area. This analysis assumes a direct relationship between number of new structures and
number of additional motorized watercraft, resulting in a related effect on noise energy.
Therefore, in the areas where the number of structures would double, the number of
watercraft would double, resulting in doubling the noise energy associated with
watercraft. This would result in a significant impact on noise.
In some areas shown, the number of structures merely double; in others, the number
would increase by an order of magnitude. In areas where sound energy would increase
to four times the existing, noise levels would increase by at least 6 dBA, which would be
a clearly noticeable increase. Generally, in the areas that do have a large increase in
structures, the greatest increase would be in numbers of buoys.
TRPA adopted a PSIL maintained by the 600-foot no-wake zone. This standard would
also assist in reducing noise impacts associated with the increase in boating activity
associated with Alternative 1. To reduce the impacts associated with increased noise
resulting from increased boating activity, the following mitigation measures would be
necessary.
Mitigation Measure 9.1.1a: Use of signing and other educational means to advise the
public of potential noise problems and increase awareness of the 600-foot no-wake
zone.
Mitigation Measure 9.1.1b: To prevent exceedances of noise standards, the following
measures will be implemented based on the status of the project area. The increased
noise levels associated with increased structures will be determined by expert analyses
of the specific location and proposed project(s). Noise analyses will be required where
structures are expected to increase the number of boats on the lake by 5 or more.
In shoreline areas found to be out of attainment of TRPA’s CNEL standard based on
long and short term monitoring included in the sticker program, no new buoys will be
allowed.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 15
In shoreline areas found to be within 3 dBA of the CNEL standard based on the
monitoring designated above (prior to the addition of structures), the increase in buoy
density at buildout must be consistent with maintaining noise levels at or greater than 1
dBA below the CNEL standard.
In shoreline areas where an increase in structures is expected to increase noise by
greater than 3 dBA, buoy density will be limited to correlate with an increase in noise of 3
dBA or less.
The monitoring of this mitigation measure will be partially or fully funded and
implemented by the sticker program.
Implementation of mitigation measures 9.1.1a and 9.1.1b would reduce this potential
significant impact to a level that is less than significant.
Impact 9.1.2: The No Project Alternative would result in an increase in noise from vehicle
traffic accessing public facilities.
In addition to the doubling of sound energy from watercraft under this alternative, these
facilities also would produce increased noise related to vehicle traffic accessing public
facilities. The cumulative effect of these activities would produce a significant impact on
noise.
Mitigation Measure 9.1.2a: To prevent exceedances of noise standards associated with
increases in vehicle traffic, the following measures will be implemented based on the
status of the project area. The increased noise levels associated with increased
structures will be determined by expert analyses of the specific location and proposed
project(s). Noise analyses will be required where structures are expected to increase the
number of boats on the lake by 5 or more.
In areas found to be out of attainment of TRPA’s CNEL standard based on long and
short term monitoring included in the sticker program, no new structures which would
increase the number of vehicles in the area will be allowed unless mitigation strategies
can be identified to reduce the noise impact to a less than significant level.
In areas found to be within 3 dBA of the CNEL standard based on the monitoring
designated above (prior to the addition of structures), the increase in shoreline structures
at buildout must be consistent with maintaining noise levels at or greater than 1 dBA
below the CNEL standard.
In areas where an increase in structures is expected to increase noise by greater than 3
dBA, the increase in structures will be limited to correlate with an increase in noise of 3
dBA or less.
Non-Significant Noise Impacts
The No Project Alternative could result in noise impacts to wildlife. Under this alternative,
the increases in noise levels resulting from this alternative would not be forecasted to
create significant impacts to the sensitive wildlife areas identified previously. TRPA has
adopted a 600-foot no-wake zone standard to implement the PSIL standard to maintain
certain noise levels on shore. This standard, when fully enforced, would assist in
controlling noise to a level that would be conducive to maintaining the wildlife
management zones. This would not be a significant impact and no mitigation is required.
Additionally, measures to protect wildlife are included in the wildlife chapter of this
analysis.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 16
Beneficial Noise Impacts
There would be no beneficial impacts on noise with the No Project Alternative.
ALTERNATIVE 2 – PROPOSED PROJECT ALTERNATIVE
This alternative would result in revisions to the Shorezone provisions of the Code based
on the consensus agreements of the Shorezone Partnership Committee, direction from
the Shorezone Policy Committee, and TRPA staff revisions for cleaning up, streamlining,
and environmental adequacy. The general goal of this proposal is to assure all littoral
parcels are eligible to apply for a pier and sufficient buoys to access the lakes of the
Region, that all related impacts would be mitigated, and that all applicable environmental
thresholds would be attained. The prohibition on the location of Shorezone structures in
prime fish habitat would be eliminated under this alternative. This alternative would also
include a new scenic review system and would introduce the concept of private, quasipublic, and public structures to provide the basis for design standards and deviation from
those standards.
Increased Boat Usage
This alternative could affect CNEL standards around the entire Lake. By lifting location
standards based on prime fish habitat, new or expanded structures would accommodate
more watercraft, which would very likely pose a significant impact to noise standards.
Alternative 2 would result in approximately 33 percent more structures at buildout than
Alternative 1.
Additional private structures would result in increased localized noise from motorized
watercraft. More public structures would generate increased noise from motorized
watercraft, and the associated traffic and parking facilities, especially where new PWC
operations would be located. Alternative 2 would create significant noise impacts
throughout the Shorezone area by increasing the number of structures in the Shorezone.
Of the 203 grid units of 2,000-feet that make up the Shorezone of Lake Tahoe,
Shorezone structures would at least double on approximately 62 units as a result of full
implementation of Alternative 2. This would be more than Alternatives 1 and 4, but fewer
than Alternative 3. In many of these units, the increase in structure number would be
much higher than a mere doubling, so the noise impacts associated with the increases
would be higher than 3 dBA. It should be pointed out that analyzing purely the number of
structures by Alternative does not give a perfect comparison because the number of
structures does not correspond proportionally to the boating trips in each alternative.
Alternative 2 represents a 74 percent increase in structures from the 1998 base year, but
only a 57 percent increase in boating use. The overall boating associated with
Alternative 2 would be approximately 16 percent higher than that of Alternative 1,
although the number of structures would be 33 higher. Implementation of Alternative 2
would result in less public structures than Alternative 1.
Some of the impact sites also correspond with certain wildlife zones. This would create
additional potential impacts to wildlife in these areas. Noise impacts associated with
increased boating at Emerald Bay potentially conflicts with Bald Eagle management
sites, Osprey nesting, and waterbird habitat management zones. Increased boating
activity also could impact Osprey north of Zephyr Cove, around the Glenbrook area, and
Dollar Point. Conflicts could also arise between boating and the waterbird habitat
management zone in Rabe Meadow near Stateline on South Shore.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 17
Vehicles Accessing Public Facilities
In addition to the noise associated with motorized watercraft, noise impacts resulting
from vehicles accessing additional public facilities would also occur. Overall, public
facilities would be forecasted to increase by approximately 47 percent, and there would
be approximately 25 units (of the 203 grid units) where public structures are forecasted
to double. Most of these would result in increased vehicle traffic to the sites, although
some of these would not be accessible by automobile.
Significant Noise Impacts
Impact 9.2.1 The Proposed Project would result in an increase in noise from boating
activity.
As identified above, full implementation of Alternative 2 would result in significant noise
impacts; specifically, in local areas where the noise would increase by 3 dBA or greater.
In those areas where full buildout of buoy fields is anticipated, the noise associated with
the increase in boating could rise substantially. This would result in a significant impact
on noise.
Implementation of Mitigation Measures 9.1.1a and 9.1.1b would reduce this potential
significant impact to a level that is less than significant.
Impact 9.2.2: The Proposed Project would result in an increase in noise from vehicle
traffic accessing public facilities.
With this alternative, certain areas would experience additional significant noise impacts
resulting from an increase in public facilities. Not all of these sites would be accessible
by automobile, and so would not result in any impacts in addition to that from the
motorized watercraft. However, the majority of these sites would have significant impacts
from both motorized watercraft and from vehicles accessing the sites.
Implementation of Mitigation Measure 9.1.2a would reduce this potential significant
impact to a level that is less than significant.
Non-Significant Noise Impacts
The Proposed Alternative could result in noise impacts to wildlife. Under this alternative,
the increases in noise levels would not cause any significant impacts to the wildlife
impact areas identified previously. TRPA has adopted a 600-foot no-wake zone standard
to implement the PSIL standard to maintain certain noise levels on shore. This standard,
when fully enforced, would assist in controlling noise to a level that would be conducive
to maintaining the wildlife management zones as identified above. This would not be a
significant impact and no mitigation is required.
Beneficial Noise Impacts
There would be no beneficial impacts on noise with the Proposed Project Alternative.
ALTERNATIVE 3 – NO FISH HABITAT RESTRICTIONS ALTERNATIVE
This alternative would continue all Shorezone provisions of the current Code, except that
the prohibitions on Shorezone structures located in fish habitat areas would be
eliminated.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 18
Increased Boat Usage
This alternative would affect CNEL standards around the entire Lake. With the lifting of
location standards based on prime fish habitat, new or expanded structures could
accommodate more watercraft, which could be significant. Alternative 2 would result in
approximately 70 percent more structures at buildout than Alternative 1.
Additional private structures would result in increased localized noise from motorized
watercraft. More public structures would generate increased noise from motorized
watercraft, and the associated traffic and parking facilities, especially where new jet-ski
operations would be located. Alternative 3 would create significant noise impacts
throughout the Shorezone area by increasing the number of structures in the Shorezone.
Several areas around the Lake would experience a doubling of Shorezone structures. Of
the 203 grid units, Shorezone structures would at least double on approximately 77 units
as a result of full implementation of Alternative 3. This rate would be the highest of all the
alternatives considered. In many cases, the increase would be much higher than merely
doubling, so the noise impacts associated with the increases would be higher than the 3
dBA. It should be pointed out that analyzing purely the number of structures by
Alternative does not give a perfect comparison because the number of structures does
not correspond proportionally to the boating trips in each alternative. Alternative 3
represents a 122 percent increase in structures from the 1998 base year, and a 92
percent increase in boating use. The overall boating associated with Alternative 3 would
be approximately 42 percent higher than that of Alternative 1, although the number of
structures would be 70 percent higher. Alternative 3 would result in both the highest
number of structures (public and overall) and the highest boating use.
As with the other alternatives, some of the impact sites also correspond with certain
wildlife zones. The areas of conflict for this alternative would be the same noted for
Alternative 2, although the degree of severity expected in this alternative would be
greater.
Vehicles Accessing Public Facilities
In addition to the noise associated with motorized watercraft, noise impacts would also
result from vehicles accessing the additional public facilities. Overall, this alternative
would increase public facilities by approximately 147 percent, creating approximately 42
areas where public structures would double. Most of these would result in increased
vehicle traffic to the sites, although some of these would not be accessible by
automobile.
Significant Noise Impacts
Impact 9.3.1: The No Fish Habitat Restrictions Alternative would result in an increase in
noise from boating activity.
With this alternative, noise impact sites are those where structures are forecasted to at
least double as a result of full implementation of Alternative 3. Significant impacts would
occur in those areas. While most of the areas may experience an increase in noise of 3
dBA, some would likely experience a much higher increase in noise. Although boating
trips associated with Alternative 3 would be higher than each of the other alternatives, no
mitigation measures in addition to those recommended for Alternatives 1, 2 and 4 are
proposed. This would result in a significant impact on noise.
Implementation of Mitigation Measures 9.1.1a and 9.1.1b would reduce this potential
significant impact to a level that is less than significant.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 19
Impact 9.3.2: The No Fish Habitat Restrictions Alternative would result in increased
noise from vehicle traffic accessing public facilities.
With this alternative, certain areas would experience a significant increase in public
structures, resulting in significant noise increases associated with boating activity and
with vehicle traffic accessing the public facilities. Noise levels in these areas would
increase by at least 3 dBA, resulting in a level that is significant.
Implementation of Mitigation Measure 9.1.2a would reduce this potential significant
impact to a level that is less than significant.
Non-Significant Noise Impacts
The No Project Alternative could result in noise impacts to wildlife. The increases in
noise levels with this alternative would not cause significant impacts to the wildlife areas
identified previously. TRPA adopted a 600-foot no-wake zone standard to implement the
PSIL standard to maintain certain noise levels on shore. This standard, when fully
enforced, would assist in controlling noise to a level that would be conducive to
maintaining the wildlife management zones as identified above. This would not be a
significant impact and not mitigation is required.
Beneficial Noise Impacts
There would be no beneficial impacts with the No Fish Habitat Restrictions Alternative.
ALTERNATIVE 4 – PUBLIC STRUCTURES ONLY ALTERNATIVE
This alternative would remove the prohibition on locating Shorezone structures in prime
fish habitat. The prohibition of Shorezone structures within 200 feet of a stream mouth
would remain unchanged. However, in order to mitigate existing and additional
development and to promote public access, this alternative allows new or expanded
structures for public facilities (open to the general public) only. No new or expanded
private structures are allowed.
Increased Boat Usage
This alternative, by restricting construction to public facilities, would have an overall
lesser impact than the other alternatives. This would be true because fewer Shorezone
parcels would be eligible for development. However, the allowable development would
be public facilities, which has the potential to create greater noise impacts associated
with vehicle traffic accessing the public facilities. Although total structures in the
Shorezone for this alternative are estimated to increase by 38 percent, public structures
are estimated to increase by approximately 140 percent.
With this alternative, several areas exist where development would at least double. Of
the 203 grid units, Shorezone structures would at least double on approximately 17 units
as a result of full implementation of Alternative 4. In many cases the increase would be
much higher than merely doubling, so the noise impacts associated with the increases
would be higher than 3 dBA. It should be pointed out that analyzing purely the number of
structures by alternative does not give a perfect comparison because the number of
structures does not correspond proportionally to the boating trips in each alternative.
Alternative 4 represents a 38 percent increase in the total number of structures from the
1998 base year, and a 58 percent increase in boating use. This would be because the
structures that would be allowed by this alternative would be public facilities, and so
would have a greater rate of boating activity. The overall boating associated with
Alternative 4 would be approximately 16 percent higher than that of Alternative 1,
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 20
although the number of structures would be only five percent higher. Alternative 4 would
result in approximately the same amount of boating activity as Alternative 2.
As with the other alternatives, some of the impact sites also correspond with certain
wildlife zones. The areas of conflict for this alternative would be the same noted for
Alternative 2, although the degree of severity expected in this alternative would be
greater due to the focus on multiple use structures. For additional discussion of impacts
to wildlife, see Chapter 12.
Vehicles Accessing Public Facilities
In addition to the noise associated with motorized watercraft, there would also be noise
impacts resulting from vehicles accessing the additional public facilities. Overall, public
facilities are estimated to increase by approximately 141 percent, and there would be
approximately 25 units (of the 203 grid units of 2,000 feet) where public structures are
estimated to double. Most of these would result in increased vehicle traffic to the sites,
however some of these would not be accessible by automobile.
Significant Noise Impacts
Impact 9.4.1: The Public Structures Only Alternative would result in an increase in noise
from boating activity.
Although the number of noise impact sites for this alternative would be lower than for the
other alternatives 1, 2, and 3 the impacts at the sites where additional development
would be allowed would be significant. Those sites represent areas where the number of
structures would at least double upon full implementation of Alternative 4, representing a
minimum increase in noise levels of 3 dBA. The increases would result from the
increased boating activity and would result in a significant impact on noise.
Although the overall impacts associated with Alternative 4 would be less than
alternatives 1, 2, and 3 the impacts at the public facility sites would still be significant.
Similar measures required for the other alternatives would also needed for Alternative 4,
although site specific application would be required at fewer locations.
Implementation of Mitigation Measures 9.1.1a and 9.1.1b would reduce this potential
significant impact to a level that is less than significant.
Impact 9.4.2: The Public Structures Only Alternative would result in increased noise from
vehicle traffic accessing public facilities.
In addition to the increase in noise from motorized watercraft, the public structures
allowed with this alternative would also generate additional noise from boating activity
and vehicle traffic accessing the public facilities. This would result in a significant impact
on noise.
Implementation of Mitigation Measure 9.1.2a would reduce this potential significant
impact to a level that is less than significant.
Non-Significant Noise Impacts
There would be no non-significant impacts on noise with the Public Structures Only
Alternative.
Beneficial Noise Impacts
There would be no beneficial impacts on noise with the Public Structures Only
Alternative.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
Page 9- 21
ALTERNATIVE 5 – REDUCED DEVELOPMENT ALTERNATIVE
This alternative would prohibit the construction of private single-use Shorezone
structures. Under this alternative, only multiple use structures would be permitted and
would require a 2 to 1 structure reduction mitigation for private multiple use and quasipublic structures, and a 1 to 1 structure reduction mitigation for public multiple use
structures.
Significant Noise Impacts
Impact 9.5.1: The Reduced Development Alternative would result in an increase in noise
from boating activity.
Similar to Alternative 4, this alternative would rely on multiple-use piers, resulting in
noise impacts at the multi-use sites. The overall number of noise impact sites for this
alternative would be lower than those for the other alternatives. Because this alternative
also incorporates a reduction in private piers, noise levels in those locations where piers
or buoys are removed will decrease. However, there would be a localized increase in
noise levels under this alternative due to the concentration of boating activities in specific
areas where multiple use structures increase the number of boats in an area. Although
the increase in noise from boating activity near multiple-use piers would be partially
offset by the reduction in noise from private piers, there may be significant impacts to
noise in those localized areas and therefore mitigation is required.
Implementation of Mitigation Measures 9.1.1a and 9.1.1b would reduce this potential
significant impact to a level that is less than significant.
Impact 9.5.2: The Reduced Development Alternative would result in increased noise
from vehicle traffic accessing public facilities.
As with Alternative 4, this alternative would result in increase in noise from motorized
watercraft. In addition, the multiple-use structures allowed with this alternative would
also generate additional noise from concentrated boating activity and vehicle traffic
accessing the facilities, although this increase would be comparable and potentially less
than the levels with Alternative 4. However, The concentrated activities would result in a
significant impact on noise.
Implementation of Mitigation Measure 9.1.2a would reduce this potential significant
impact to a level that is less than significant.
Beneficial Noise Impacts
There may be some beneficial impacts on noise in those areas where the number of
private piers are reduced, however noise levels in public areas where there is an
increase in activities are expected to increase. Therefore, overall there are no significant
beneficial impacts on noise under the Reduced Development Alternative.
Lake Tahoe Shorezone Ordinance Amendments Administrative Draft EIS – April 2004
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