Cory Lakes CDD

A few of the residents living behind the conservation area behind the playground have requested that the community put a wall between the playground and their homes to reduce sound and line of sight. Bob and John met with the residents to discuss options. Some options that were discussed were planting line of bamboo plants. The concern with this option was that they would be expensive and there was no assurance that they would block out sound sufficiently.

The purpose of this topic is to discuss ideas and thoughts on alternative solutions.

Questions in my mind are:
- How will we know that something that is built will work?
- Must the structure be built between the playground and the conservation area, or can it be built behind the trees within the conservation area, or can it be built between the conservation area and the homes?

What do other supervisors and our facilities manager think about this issue?

Here are a few answers,

1) The Bamboo although being $13,000 is the cheapest option. And if it helps dampen the noise some then another row can be added to areas of concern to further dampen the noise. Thus giving a noise barrier but still not swaying far from the conservation look.

2) Building a wall- Tonja, our engineer, discussed this with their in house parks engineer who said the same thing the engineer from Acoustiblok had previously told me.
A) The wall would have to be twice as high as the originating source and built within feet of the source to be effective. So we would need a wall 20 feet high built right next to the playground and pool to have an effect.
B) The wall would help with low pitch noises like motors and vibrations but not as much the high pitch.

With pricing a precast wall that is recommended for sound dampening around some roads and play areas, cost was put at between $48,000 and $65,000 for a wall only 6 feet tall and 150- 200 feet long. A wall three times as tall would be considerably more expensive.

3) I do not believe we can do anything inside the wetland setback of the conservation area.

John, thanks for the info. So a bamboo wall would also have to be 20 feet high. I'm assuming they will grow that way. If we have to double the wall then it would $26,000. Are my assumptions correct?

The bamboo would indeed grow over time adding to the sound dampening. We would't need a full row of bamboo for the second row, only filling in any areas where the conservation isn't as dense. I believe the open area through the conservation between the playground and the back of the residences on St. Lucia that you can see the backs of the residents lanai is where most of the noise is passing through. So if needed, this would be where I would think to add more bamboo.

John, In your opinion would the planned location of the bamboo block visual site to the back of the home's lanais?

I have discussed this with LMP and we would make sure that the placement is to where we would get maximum coverage in the open areas.

I have walked this area many different times on many different occasions and have not been able to see any lanais in this area. I am not in agreement with a wall of any kind being placed here. I think that we could allow the residents the option to put whatever kind of wall they would like to on their own property, but I don't think that this is a community responsibility.

It seems to me that this whole issue is based on the assumption that there is intolerable noise levels for the homes behind the playgrounds. If that were proven or disproven then the issue would be validated or invalidated. So, I have contacted an engineering firm that does outdoor noise studies to see if it would be cost effective to do a study and make this issue a factual vs. speculative discussion.

I'll update the group when I know more.

The engineering firm pointed me to the city regulations which state:
- In all areas of the City of Tampa other than those areas listed in subsection (b)(1) above, the average measurement taken between (10) and twenty (20) seconds shall be no greater than the maximum levels set out below. The measurement shall be taken from a receiving property at the property line closest to the noise generating property:
a. Sixty (60) dBA or sixty-five (65) dBC between the hours of 7:00 a.m. and 10:00 p.m.
b. Fifty-five (55) dBA or sixty-five (65) dBC between the hours of 10:00 p.m. and 7:00 a.m.

And,
(c) Exemptions. The provisions of this section shall not apply to:
(8) Noise which results from the reasonable use, recreational enjoyment or maintenance of residential property located in the City of Tampa including, but not limited to, noise made by children, lawn mowers, chippers, clippers, blowers, tools, power tools and tractors;

The exemption is for residential property which is more stringent that public property so the playground is likely exempted as well.
Even without the exemption, their is no chance that the average decibel level between 10 to 20 seconds exceeds 55 dBA because the "screams" are only momentary.

So, based on the law, the CDD is under no obligation to mitigate the sound from the playground.

As far as a noise analysis study goes, it would only demonstrate the peak spikes and would cost about $600 to do ourselves. If the homeowners want to carry out the noise study and show us the data, I have no objections to that.

But, for now, I am against the bamboo which may or may not work in blocking the sound and will cost no less than $16,000.

Cyril I'm agreement with your suggestions and thank you for doing the research on your study.