HomeMy WebLinkAboutDrainage Waiver Request
To: City of Carmel
City of Carmel Engineering Department
One Civic Square
Carmel, Indiana 46032
Date: November 15, 2021
Attn: Alex Jordan, John Thomas
Re: Albany Village
Alex, John,
Please consider this letter as a formal request to seek a waiver for the following item at Albany Village:
Stormwater Technical Standards Manual Section 302.08 Additional Requirements for Dry Bottom Facility Design
Provisions shall be incorporated into facilities for complete interior drainage of dry bottom facilities, including a
minimum 1% bottom slope in all directions if tile underdrains are provided and a minimum of 2% if no
underdrains are provided.
Albany Village is proposing a native bottom dry detention facility as a secondary BMP for Lake #2. In order to
provide the required water quality volume and positive drainage to the native bottom dry detention facility, we
had to set the lowest elevation of the native bottom dry detention facility at the same elevation as the normal
pool for Lake #2. Due to the lack of vertical fall throughout the site, we are only able to provide 0.5% slope
through the dry detention basin. With the bottom of the dry detention facility at the same elevation of the
normal pool, we are not able to provide under drains for the dry detention basin. In lieu of not providing SSD’s
for the dry detention basin, we will be providing a 3’ wide low flow rock channel through the middle of the
detention facility. Please let me know if there are any questions or if any additional information is needed.
Sincerely,
Chad James, PE
Project Manager