The Township of Clay Banks, Wisconsin approved a wind energy ordinance to govern the construction of wind energy conversions systems (turbines) within the Township's boundaries. The full ordinance can be downloaded by clicking on the links at the bottom of this page. The sections on Noise and Setback requirements are excerpted and presented below.

G. Noise:

1. Audible Sound Limit

a. No Wind Turbine or group of turbines shall be located so as to cause an exceedance of the pre-construction/operation background sound levels by more than 5 dBA or dBC. The background sound levels shall be the L90 dB sound descriptor (both A and C weighting) measured during a pre-construction noise study during the quietest time of evening or night. Measurements shall be for ten (10) minutes or more. L90 results are valid when L10 results are no more than 15 dB above L90 for the same time period. Noise sensitive sites are to be selected based on wind farm’s predicted sound emissions (in dBA, dBC and 1/3 octaves to blade passage frequency), which are to be provided by developer.

b. A 5 dB penalty is applied for pure tones or when the sound emissions fluctuate in amplitude or frequency over time in reasonable synchronicity with the blade revolution.

2. In-Audible (e.g. Low Frequency) Sound Limit

a. Not to exceed dBC-dBA greater than 20 dB inside or outside any occupied structure.

3. General Clause

a. Not to exceed 40 dBA or dBC within 100 feet of any occupied structure.

4. Requirements:

a. All instruments must meet ANSI Type 1 performance specifications.

b. Procedures must meet ANSI S12.9 and other applicable ANSI standards.

c. Measurements must be made when ground level winds are 10 mph or less. Background sound measurements are with winds of 5 mph or less. Wind shear in the evening and night often result in low ground level wind speed. At turbine fan heights, the wind is at or above nominal operating wind speeds.

d. IEC 61400 procedures are not suitable for enforcement of these requirements. ANSI standards shall be followed for testing procedures.

5. In the event the noise levels resulting from the WECS exceed the criteria listed above, a waiver to said levels may be granted by the Town Board provided that the following has been accomplished:

a. Written consent from the affected property owners has been obtained stating that they are aware of the WECS and the noise limitations imposed by this Ordinance, and that consent is granted to allow noise levels to exceed the maximum limits otherwise allowed; and

b. If the applicant wishes the waiver to apply to succeeding owners of the property, a permanent noise impact easement has been recorded in the Office of the County Register of Deeds which describes the benefited and burdened properties and which advises all subsequent owners of the burdened property that noise levels in excess of those permitted by this Ordinance may exist on or at the burdened property.

K. Setbacks:

1. Setbacks shall be measured from the outermost edge of the closest of the circular path of the wind turbine rotor blade. The Town Board may increase the following minimum setbacks on a case-by-case basis, in order to protect public health and safety.

a. Participating Property Line: 1.1 times the total height of the Wind Turbine from the nearest property line of a participating property owner.

b. Non-Participating Property Line: Five (5) times the rotor diameter but not less than 1,000 feet from the nearest property line of a non-participating property, unless the owner of the non-participating property grants an easement for a lesser setback. The easement must be recorded with the County Register of Deeds and may not provide for a setback that is less than 1.1 times the total height of the Wind Turbine.

c. Public Roads and Highways: 1,000 feet or three (3) times the total height of the Wind Turbine, whichever is greater.

d. Above Ground Power/Telephone Lines: 1,000 feet or three (3) times the total height of the Wind Turbine, whichever is greater, from the nearest above-ground public electric power line or telephone line.

e. Residences & Other Buildings: 2,640 feet from the nearest residence, business, school, daycare facility, church, hospital and other sensitive receptors.

f. Wetlands: 1,000 feet from all sinkholes and wetlands.

g. Water Bodies Setbacks: 1,000 feet from the ordinary high water mark of all navigable water bodies.

h. Parks & Public Property: 2,640 feet from any town, county or state park, property, recreational or rest area.

i. Spacing and Density: Minimum setback distances between turbines shall be (2) times the total height of each WES.

Web link: http://betterplan.squarespace.com/town-of-clay-ban...

Download File(s):
Clay_Banks_Wind_Ordinance_Comm._Approved_05.03[1].pdf (577.98 kB)
Table_of_Contents.Town_of_Clay_Banks.05.03.08[1].doc (28 kB)