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Noise 101 Definition of noise – any unwanted sound Definition of noise – any unwanted sound Measured in sound pressure levels (decibels – dB) Measured.

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Presentation on theme: "Noise 101 Definition of noise – any unwanted sound Definition of noise – any unwanted sound Measured in sound pressure levels (decibels – dB) Measured."— Presentation transcript:

1 Noise 101 Definition of noise – any unwanted sound Definition of noise – any unwanted sound Measured in sound pressure levels (decibels – dB) Measured in sound pressure levels (decibels – dB) - increase of 3 dB barely perceptible - increase of 5 dB is clearly noticeable - increase of 10 dB is heard twice as loud Measured L10 and L50, State/Fed standards use L10 Measured L10 and L50, State/Fed standards use L10 - Residential L10 Std = 65 dB day and 55 dB night (L10 of 65 dB means that in one hour of heaviest traffic, noise level was at or greater than 65 dB for 6/60 minutes) (L10 of 65 dB means that in one hour of heaviest traffic, noise level was at or greater than 65 dB for 6/60 minutes) - Federal noise abatement criteria for Category B = 70 dB (Category B is for residential and recreational) (Category B is for residential and recreational) Noise Level Comparison chart: Noise Level Comparison chart: Jet engine at 75 feet 140 dB Heavy Truck Traffic 80 dB Business Office 70 dB Conversational Speech 60 dB Secluded woods 30 dB

2 Noise Modeling Results around C-2 and C-2A Looking at specific receptor points of interest (see map): R8 near CSAH 11/New US 212 R9 near Chaska athletic field R10 in Downtown Chaska (on TH 41 near 2 nd street) R13 along C-2A east of Chaska Lake in USFWS Refuge R14 just east of where C-2 crosses existing TH 41 R19 just north of railroad along C-2A R20 near Jackson Heights

3 R8 Noise Information (near CSAH 11/new US 212) Modeling Results Modeling Results L10 in dB L10 No-build in dB L10 building C-2 as studied66 dB Conclusions Conclusions Expected noise increase only slightly above State Standard

4 R9 Noise Information (by 1 st St/RR near Chaska Athletic Field) Monitoring/Modeling Results Monitoring/Modeling Results L10 monitored in Oct 2005 (before new US 212)64 dB L10 in 2004 model 61 dB L10 No-build in dB L10 building C-2 as studied68 dB L10 building C-2A as studied66 dB Conclusions Conclusions L10 level for C-2 as studied is only 2 dB less than C-2A as studied (may be different elevations, etc.). This is not a perceptible difference. Consider leaving buffer of trees for visual screen/character retention, but not very effective for more noise mitigation

5 R10 Noise Information (near 2 nd St and TH 41 in downtown Chaska) Modeling Results Modeling Results L10 in 2004 (before new US 212 opened)73 dB L10 No-build in dB L10 building C-2 as studied70 dB L10 building C-2A as studied71 dB* Conclusions/Questions: Conclusions/Questions: Noise standards are already exceeded and only slightly increase with no-build scenario. Why does C-2A show higher noise level when farther away (less ADT, different elevation, etc.)?

6 R13 Noise Information (In Refuge east of Chaska Lake along C-2A) Modeling Results Modeling Results L10 in 2004 (before new US 212 opened)54 dB L10 No-build in dB L10 building C-2 as studied65 dB L10 building C-2A 73 dB Conclusions: Conclusions: Noise levels only slightly increase in no-build scenario. Building C-2 as studied substantially increases noise, yet still remains at 65 dB (state threshold) and well below 70 dB (federal threshold). Building C-2A as studied exceeds state and federal threshold.

7 R14 Noise Information (just east of where C-2 crosses existing TH 41 Modeling Results Modeling Results L10 in 2004 (before new US 212 opened)57 dB L10 No-build in dB L10 building C-2 as studied64 dB L10 building C-2A 58 dB Conclusions: Conclusions: Both C-2 and C-2A result in noise levels under the state and federal levels at this receptor location.

8 R19 Noise Information (just north of railroad along C-2A) Modeling Results Modeling Results L10 in 2004 (before new US 212 opened)56 dB L10 No-build in dB L10 building C-2 as studied59 dB L10 building C-2A as studied67 dB Conclusions: Conclusions: Levels remain below state and federal thresholds for C-2 as studied. Only state threshold is exceeded with C-2A.

9 R20 Noise Information (near Jackson Heights) Monitoring/Modeling Results Monitoring/Modeling Results L10 monitored in Oct 2005 (prior to new US 212)59 dB L10 in 2004 (before new US 212 opened)63 dB L10 No-build in dB L10 building C-2 as studied65 dB L10 building C-2A as studied68 dB Conclusions/Questions: Conclusions/Questions: Noise levels remain at or below state standards. Question why both C-2 and C-2A as studied did not increase more with local and regional interchange here.


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