×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

FEMA Zone A

FEMA Zone A

FEMA Zone A

(OP)
We have a project that is in a FEMA Zone A floodplain.  However, it is no more than a drainage swale running through an agricultural field.  The Zone A area continues up to the beginning of the swale.  The uppermost portion of this swale has a drainage area of less than 4 acres,  This can't be a FEMA floodplain.  Is there a minimum drainage area in determining the FEMA Zone A boundary?  All information I've looked at does not give a minimum drainage area.

RE: FEMA Zone A

There is no watershed critieria for delineating a FEMA flood zone.  But what are seeing is an Approximated Study - a conservative "sketch" of an arbitrary elevation which mimics USGS 20' interval contours.  It almost never follows the local contours to any acceptable precision (say, 2' intervals).  It is not intended to, it is just a guideline...unless a Detailed Study was done, which will have sections enumated along the reach.

If you are in an A FIRM Zone, I don't think there has been a Detailed Study done by FEMA.  Therefore, you are free to delineate one.  A licensed engineer can model the reach.  He or she will have to file a Letter of Map Change (LOMC, or LOMR) to make it legal with the Corp.  But you may not even have to do that for local development criteria.  You may just be able to delineate it.

Beware, doing this delineation could effectively (and legally) "rezone" the area as a Flood District, IF your local ordinance allows for that.  This could backfire on you and make your development criteria more strict.

RE: FEMA Zone A

(OP)
Thanks for the info.....

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources