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Figure 1.1 Waterglen P.U.D. Vicinity
Waterglen P.U.D. Noise Impact Assessment
Page 2
4.0 REFERENCES
i
Fort Collins Code, Sections 20-21 to 20-29, Article II, Noise.
FHWA Highway Traffic Noise Prediction Model, FHWA-RD-77-108, December, 1978.
HMMH,1993. "Review of Mid -Coast Noise Study", by Harris Miller Miller and Hanson,
Inc., March 15, 1993.
! U.S. Code of Federal Regulations, Title 23, Part 772. Procedures for Abatement of
Highway Traffic Noise and Construction Noise.
Waterglen P.U.D. Noise Impact Assessment
Page 13
3.0 FINDINGS AND RECOMMENDATIONS
The modelling effort described above indicates that a barrier approximately 10 feet
high will adequately protect the nearest residences to I-25 from noise levels considered
objectionable by the FHWA for design purposes.
Since the Fort Collins Noise Control Code is designed to prevent the generation
of unreasonable noise at a development site, it is not clear that it can be applied to noise
m which is generated at I-25, a source outside the jurisdiction of the City. Moreover, given
1 that the future traffic on I-25 in the year 2015 will not be substantially greater than the
current traffic along some of the City's major arterials, it is possible that application of
i this stringent noise control requirement would constrain residential development in other
J parts of the City if applied to all new developments. Therefore, this analysis is based on
the commonly -used criteria noise levels specified by the U.S. Federal Highway
j Administration and the Colorado Department of Highways (CDOT) in designing noise
1 barriers to protect communities from highway noise.
iIt is recommended that a barrier approximately 10 feet high be designed as part
of the development to run along the entire length of the eastern boundary of the P.U.D.
To make this barrier most effective, it should continue to the southeast corner of the site,
cj and wrap around to the south of multi -family buildings I, J, and K in Dunattar
Commons. The barrier can be designed as a berm (appropriately landscaped), as a
masonry or poured concrete wall, or a combination berm and wall totalling ten feet or
more. The mini -storage units near the northeast corner of the P.U.D. can be incorporated
into the barrier design, as long as they, in conjunction with an earth berm, are at least
ten feet high.
' It is further recommended that the owner investigate the possibility that some
portion of the cost of the barrier may be borne by CDOT. CDOT builds noise barriers
to protect communities from noise along the interstate highways in Colorado, but the
criteria they use to determine if a barrier is cost-effective will most likely deny State
�i funding for this project at this time. However, when I-25 is eventually widened to six
J lanes the environmental studies carried out at that time by CDOT will investigate noise
impacts to adjacent communities. Since The Waterglen P.U.D. will be adequately
G. protected by a ten -foot berm as of its opening, future additional noise protection due to
improvements to I-25 may be the responsibility of the CDOT.
The train noise analysis shows that the northwest portion of the development will
experience noise levels which will approach but not exceed the FHWA and EPA noise
impact criterion. Significant future increases in train traffic may require some additional
noise shielding, but this is not required at this time.
IWaterglen P.U.D. Noise Impact Assessment Page 12
1
2.4 Projected Train Noise Levels
The Burlington Northern operates a main line which passes close to the northwest
corner of the P.U.D. site. Discussions with the Burlington Northern Railroad' revealed
that the line is used currently by 10 trains per day, and that they operate at a speed of
25 miles per hour in the area. The trains consist of from 50 to 100 cars. To determine the
impact of these. trains on the property, Lq (h) values were computed.
The approach is based on solving the following equations (HMMH, 1993):
Leq = L,,, + 10 log (N * (1.5D + d)/ V] - 37.2
where:
Lm� = Maximum noise level during a train passby (see Appendix E)
N = Number of trains per hour
D = Distance to receptor from track centerline, ft.
d = Train length, ft.
V = Train speed, mph
Table 2.6 summarizes the results of the analysis. The closest lot property line is
approximately 420 feet from the rail line. At this distance, the average hourly Leq is 65
dBA, given current conditions. This falls within the Leq = 67 dBA EPA and FHWA
criterion discussed earlier. Should train traffic or speeds increase in the future noise
levels may be expected to increase as well, and the northwest portion of the
development may be subjected to levels exceeding the criterion levels. No forecast of
train traffic was available from the Burlington Northern at this time.
Table 2.6 Train Noise Analysis
Distance from
tracks
(feet)
Hourly Leq (dBA) for
number of trains per day indicated
5 trains
10 trains
15 trains
20 trains
300
63
66
68
69
400
62
65
67
68
500
61
64
.66
67
1000
59
62
64
65
1500
57
60
62
63
' Mr. R.M. (Mike) Renner, Roadmaster, Burlington Northern Railroad, 2401 East Vine, Fort
' Collins, Colorado.
Waterglen P.U.D. Noise Impact Assessment Page 11
The most practical solution to the reduction of noise at this development is to
design a barrier along the entire eastern property line which will reduce exterior noise
levels below the FHWA sound abatement criteria. The model was exercised with four
Jdifferent barrier heights: 8,10,12, and 18 feet, so as to recommend an appropriate design
height. The results of the modelling are shown in Table 2.5. As can be seen, a ten -foot
barrier (measured from existing ground level) along the east property line is sufficient
to bring the projected future noise levels below the FHWA criterion level at the
individual lot property lines closest to I-25.
Table 2.5 Model Results, Year 2015
Receptor
Modelled Noise Level (Leq(h), dBA)
(values in bold type exceed FHWA criterion)
No Barrier
Barrier Height
8 ft.
10 ft.
12 ft.
18 ft.
R4 Multifamily
67.3
66.4
65.8
64.9
61.5
Bldg. H
R5 Thornhill Place
69.8
67.2
65.8
64.1
59.9
lot #10
R6 Thornhill Place
69.5
67.5
66.3
64.7
60.3
lot #21
R7 Berwick Court
69.5
66.6
65.0
63.3
59.3
lot #10
R8 Berwick Court
69.2
67.2
66.0
64.3
59.9
lot #18
R9 Celtic Lane
66.1
65.4
64.8
64.2
60.7
lot #1
Waterglen P.U.D. Noise Impact Assessment Page 10
1
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0
LEGEND
• ROADWAY LOCATIONS: 1 - 6
■ BARRIER LOCATIONS: B1 - B7
♦ RECEPTOR LOCATIONS: R1 - R9
F - ♦ ROADWAY
ll...g BARRIERS
). Noise Mo
0 400'
SCALE
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No Text
2.3 Projected Highway Noise Levels
A noise model of the Waterglen P.U.D. and I-25 was constructed as shown in
Figure 2.1. It was calibrated to current conditions by using the traffic counts obtained
during the noise measurement period and comparing the model noise results to the
measurements.. Because traffic differed while measuring at each of the three noise
measurement sites, the calibration run was repeated for each location. The STAMINA
input and output files for the calibration runs are reproduced in Appendix B. The
calibration consisted of building into the model an existing barrier (the Vine Drive
overpass), and adjusting the so-called (c-values of the model. These parameters are used
to modify the decay rate of noise with distance to account for the type of terrain between
the source and the receiver. (x-values of 0.5 are appropriate for flat, open, soft terrain,
such as a plowed field. The calibration results are shown in Table 2.4, below. The model
is considered well -calibrated since the differences between the measured and modelled
values are less than one decibel in all cases. The human ear is not capable of discerning
differences in noise levels of less than one decibel, except in the most stringent
laboratory conditions.
Table 2.4 Calibration of the Waterglen Model
Location
Measured Lq
(dBA)
Modelled Leq
(dBA)
Difference
1 (RI)
69.1.
70.0
+0.9
2 (R2)
1 70.3
70.1
1 -0.2 11
3 (R3)
65.9
66.4
+0.5
Using this calibrated model, several runs were made using future traffic. An initial
run with no shielding gives a baseline case. This would be the noise levels expected at
the receptor locations within the P.U.D. close to I-25 in the year 2015 if no mitigation
measures were taken.
Mitigation measures for noise are possible in three areas: control at the source,
control along the path of the noise, and control at the receptor location. Control at the
source would include the use of enhanced mufflers, engine shielding, lower -noise
emitting tires, or special surfacing on I-25 designed to reduce tire -pavement noise.
Control along the noise path includes the use of barriers and berms. Control at. the
receptor would consist of special sound -proofing for residences near I-25.
Noise control at the source is beyond the scope and authority of the developers
of Waterglen P.U.D. or of the City of Fort Collins (beyond the City's ability to control
excessive noise from individual vehicles on city streets). Noise -proofing of residences
along I-25 is possible, but it does not address the issue of outside noise levels in the back
yards and other exterior locations.
Waterglen P.U.D. Noise Impact Assessment Page 8
This is a considerably larger proportion than normally used for planning purposes for
peak -hour highway traffic (5 to 7 percent heavy trucks is considered normal). However,
in order to be reasonably conservative, a 10 percent proportion of trucks for the peak
hour in the future is used in this analysis. The resulting hourly traffic on I-25 and Vine
Drive is shown in Table 2.3.
Table 2.2 Traffic Counts During Noise Measurements
Vehicle
Type
Actual Counts
One -hour Equivalent Volumes
I-25
northbound
I-25
southbound
East Vine
Drive
I-25
northbound
I-25
sou
East Vine
Drive
Counts made while measuring noise at Location 1 (14 minutes)
Cars
109
103
9
466
440
38
Trucks
19
9
3
81
38
13
Total
128
112
12
547
479
51
Counts made while measuring noise at Location 2 (15 minutes)
Cars
120
106
29
478
422
115
Trucks
19
14
5
76
56
20
Total
139
120
34
554
478
135
Counts made while measuring noise at Location 3 (15 minutes)
Cars
116
135
13
463
539
52
Trucks
17
19
4
68
76
16
Total
133
154
17
531
615
68
Table 2.3 Future Peak Hour Traffic (Year 2015)
Roadway
ADT
Peak Hour Traffic
Cars
Trucks
Total
I-25 southbound
14,600
1,183
131
1,314
I-25 northbound
12,600
1,021
113
1,134
E. Vine Drive
3,000
243
27
270
Waterglen P.U.D. Noise Impact Assessment Page 7
2.0 NOISE ANALYSIS
2.1 Noise Survey
A brief noise survey was carried out on March 24-25, 1994 to establish a baseline
for an analysis of the potential additional noise to be generated by vehicles on I-25 and
trains on the Burlington Northern line. Measurements were performed using a Quest
Model 1800 Precision Integrating Sound Level Meter, calibrated at the site with a model
CA-22 Calibrator. Appendix A contains detailed worksheets and photos of the
measurement sessions, whose results are summarized in Table 2.1, below.
Table 2.1 Field Noise Sampling Results
Location 1
(near S.E. corner of
property)
Location 2
(along east
property line)
Location 3
(100' west of east
property line)
Time i
14:02
14:26
14:44
MaxiBA)
77.6
79.8
74.9
MinimA)
45.7
49.8
52.8
L (IBA)
69.1
70.3
65.9
These readings indicate that noise levels in the vicinity of the east property line
generally approach or exceed the FHWA noise abatement criteria (Table 1.1). Since traffic
is expected to increase from current levels, this situation will get worse without
mitigative measures.
2.2 Projected Traffic Levels
Traffic on I-25 is the predominant source of noise along the eastern boundary of
the Waterglen P.U.D. As stated earlier, traffic levels in the future are expected to increase
above current levels. During the measurement period, traffic counts were kept, including
the number of heavy trucks (see Table 2.2). These large vehicles produce a large portion
of the total noise along a highway, and the proportion of heavy trucks to the total traffic
volume is an important parameter in estimating future noise.
Total daily traffic expected on an average week -day in the year 2015 was obtained
from the City of Fort Collins Transportation Department. These numbers are subject to
some adjustment as the overall city modelling process continues. It is assumed, based
on advice from the City staff, that peak hour traffic will make up 9 percent of the total
daily I-25 traffic in the year 2015.
As can be deduced from Table 2.2, the average number of heavy trucks on I-25
during an off-peak afternoon hour currently approaches 12 percent of the total volume.
Waterglen P.U.D. Noise Impact Assessment Page 6
Table 1.2 Fort Collins Maximum Permissible Noise Levels **
Land Uses
Maximum Noise [dB(A)]
Maximum
Maximum
Noise
hourly Ley,
Reading
see Note.
Residential use areas zoned R-L, R-L-P,
R-L-M, R-M, R-H, R-P, R-M-P, M-L,
M-M, or T
7:00 a.m. to 7:00 p.m.
7:00 p.m. to 7:00 a.m.
55
50
60.1
50
Business and commercial use areas zoned
B-P, B-L, B-G, H-B, or C
7:00 a.m. to 7:00 p.m.
7:00 p.m. to 7:00 a.m.
60
55
65.1
55
Industrial use areas zoned I-L and I-P
7:00 a.m. to 7:00 p.m.
7:00 p.m. to 7:00 a.m.
70
65
75.1
65
Industrial use areas zoned I-G
7:00 a.m. to 7:00 p.m.
7:00 p.m. to 7:00 a.m.
80
75
85.1
75
Note: The Fort Collins Noise Code states that between the hours of 7:00 a.m. and
7:00 p.m., the noise levels permitted may be increased by ten (10) decibels
for a period not to exceed fifteen (15) minutes in any one -hour period. If
the maximum reading is as shown above, the maximum hourly Ley is
computed as the energy mean level over one -hour which corresponds to 45
minutes at the maximum reading level combined with 15 minutes at the
maximum reading level plus 10 decibels, which effectively adds 5.1 dBA to
the maximum reading level.
** The City of Fort Collins noise control criteria are part of the Fort Collins Code
prohibiting nuisances, including unreasonable noise. The maximum permissible noise
levels refer to noise generated within a property or on the City's public right-of-way. In
this case, the noise is not generated by the developer, nor is it reasonably controllable
at the source by the developer or by the City.
Waterglen P.U.D. Noise Impact Assessment Page 5
Table 1.1 FHWA Design Noise Level/Land Use Relationships
Land Use
Design Noise Level
Description of Land Use Category
Category
Leg
A
57 dBA
Tracts of land in which serenity and quiet are
(exterior)
of extraordinary significance and serve an
important public need, and where the
preservation of those qualities is to continue
to serve its intended purpose. Such areas
could include amphitheaters, particular parks
or open spaces which are recognized by
appropriate local officials for activities requir-
ing special qualities of serenity and quiet.
B
67 dBA
Residences, motels, hotels, public meeting
(exterior)
rooms, schools, churches, libraries, hospitals,
picnic areas, playgrounds, active sports areas,
and parks.
C
72 dBA
Developed lands, properties or activities not
(exterior)
included in categories A and B above.
D
---
Undeveloped Lands.
E
52 dBA
Residences, motels, public meeting rooms
(interior)
schools, churches, libraries, hospitals, and
auditoriums.
Source: Title 23, Code of Federal Regulations, Part 772
Waterglen P.U.D. Noise Impact Assessment
Page 4
Figure 1.2 Waterglen P.U.D. Plan
Waterglen P.U.D. Noise Impact Assessment Page 3
1.0 INTRODUCTION
The Waterglen P.U.D. is a proposed mixed-use/affordable housing community
located at the northwest quadrant of the crossing of East Vine Drive and I-25 in Fort
Collins. The property developers commissioned this noise assessment study to evaluate
the expected noise levels within the new community due to external noise sources such
as 1-25 and a Burlington -Northern main line. This report documents the results of the
study, including the noise measurements carried out to characterize the current situation.
Recommendations are made for appropriate mitigative measures, such as noise walls
and berms which will reduce or eliminate noise impacts.
1.1 Approach
The noise analysis was based on noise measurements of the existing conditions
and modelling of expected future conditions. B&A conducted noise measurements at
several locations along the proposed property lines between the development and I-25.
Traffic counts on I-25, including number of large trucks, were obtained during the noise
measurement period.
The Federal Highway Administration's (FHWA) STAMINA/OPTIMA model was
used to estimate future noise. The noise and traffic measurements allowed calibration
of a model of existing conditions. Traffic counts obtained during the measurement
program were used for the calibration task. The model was then used to estimate the
locations and height of noise walls or other barriers which may be required. Impact from
noise due to the design year traffic on I-25 was estimated on the basis of exceedance of
the FHWA Noise Abatement Criterion, which for residences and other sensitive exterior
receptors is L,, = 67 dBA, as shown in Table 1.1 and Appendix D. This criterion level is
used by the FHWA and most state departments of transportation to determine the need
for noise mitigation measures due to highway improvements. The City of Fort Collins
noise control criteria were also reviewed (see Table 1.2, and Appendix Q. These criteria
are part of the Fort Collins Code prohibiting nuisances, including unreasonable noise.
The maximum permissible noise levels refer to noise generated within a property or on
the City's public right-of-way. In this case, the noise is not generated by the developer,
nor is it reasonably controllable at the source by the developer or by the City. However,
control of this external noise is possible through appropriate use of barriers.
The future condition investigated was the year 2015. This year is selected for two
reasons. First, any required noise mitigation measures should protect the development
against future traffic noise, not just that expected today. Second, reliable traffic estimates
are not available beyond the year 2015.
B&A also performed a noise analysis related to the potential impact of train noise
on the northwest corner of the property. We estimated the total current and expected
train traffic on the Burlington Northern line and established the contribution of train
noise to ambient hourly or daily Lq. Train noise data were obtained from Burlington
Northern's environmental division and other sources.
Waterglen P.U.D. Noise Impact Assessment
Page 1
Abbreviations and Acronyms
ADT Average Daily Traffic
CDOT Colorado Department of Transportation
dBA decibels (A -scale)
FHWA U.S. Federal Highway Administration
Ley (h) Equivalent sound level (energy -average of noise over a one -hour period).
STAMINA/
OPTIMA FHWA Noise Prediction Model
Waterglen P.U.D. Noise Impact Assessment Page ii
WATERGLEN P.U.D.
NOISE IMPACT ASSESSMENT
Table of Contents
List of Figures ..................................................... i
Listof Tables ..................................................... 1
Abbreviations and Acronyms .........................................
ii
1.0
INTRODUCTION .............................................
1
1
1.1 Approach ..............................................
2.0
NOISE ANALYSIS ............................................
6
2.1 Noise Survey ...........................................
6
2.2 Projected Traffic Levels ...................................
6
2.3 Projected Highway Noise Levels ............................
8
2.4 Projected Train Noise Levels ..............................
11
3.0
FINDINGS AND RECOMMENDATIONS .........................
12
13.
4.0
REFERENCES ...............................................
Appendix A Noise Measurement Worksheets
Appendix B Noise Model Input and Output Files
Appendix C Fort Collins Noise Code
Appendix D 23 CFR 772
Appendix E Excerpts from HMMH, 1993 Report
List of Figures
Figure 1.1
Waterglen P.U.D. Vicinity .................................
2
Figure 1.2
Waterglen P.U.D. Plan ....................................
3
Figure 2.1
Waterglen P.U.D. Noise Model .............................
9
List of Tables
Table 1.1
FHWA Design Noise Level/Land Use Relationships .............
4
Table 1.2
Fort Collins Maximum Permissible Noise Levels ................
5
Table 2.1
Field Noise Sampling Results .............................; ..
6
Table 2.2
Traffic Counts During Noise Measurements ....................
7
Table 2.3
Future Peak Hour Traffic (Year 2015) .........................
7
Table 2.4
Calibration of the Waterglen Model ..............• • • • • ........
Table 2.5
Model Results, Year 2015 ....................' " " ' ....
10
Table 2.6
Train Noise Analysis ....................................
11
Waterglen P.U.D. Noise Impact Assessment Page i
NOISE IMPACT ASSESSMENT
WATERGLEN P.U.D.
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BALLOFFET & Associates, Inc.