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


Drywell Freezing

Drywell Freezing

Drywell Freezing

I'm looking for a good explanation on why open structure drywells do not freeze during the winter.

I work in the northeast where typically it is assumed frost depth is around 4'. For stormwater infiltration basins we are required to install drywells (typically concrete drywell structures surrounded by coarse stone, not trenches filled with stone) to allow for winter infiltration. Requirements state drywells must extend below 4' to allow for infiltration in winter conditions. I would have assumed that because there is cold air in the drywell that there is the potential that the soil at the bottom of the drywell would freeze, the same as soil on the surface. I know i have observed catchbasin sumps frozen, but these are typically shallower than frost line. Is it simply that there isn't air circulating, with constant heat from soil that allows the air in the drywell to remain slightly warmer and not freeze? This is assuming that the grate is exposed to air and not covered in snow.

RE: Drywell Freezing

The soil at the bottom of the drywell is connected to an earth-sized thermal reservoir.

RE: Drywell Freezing

First off, that "frost depth" is only a rough idea of what you may have at any particular place. Site factors that influence depth of freezing temperatures and the effects are many. Moisture content of soil, insulation on top, frost heaving susceptibility, wind, snow depth are involved. Of course weather conditions also are variable, some winters are harsh and others easy. Lately it seems they are easier, at least for this old guy. A detailed examination of your installations may surprise you. For instance, I point to a case in LaCrosse, WI before Christmas, a gas explosion in a house was caused by a ruptured gas line in the street. I measured below freezing temps in sandy soil at 8 feet depth. Water lines there have frozen at 10 feet depth, yet building codes require footings at 4 feet. No heave in clean sand..

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! Already a Member? Login


White Paper - The Evolving Landscape of Commercial Battery-Powered Trucks
What’s driving the evolving landscape of truck electrification? What are the barriers, motivators and strategies for accelerating the electric transition? What insights and resources are available for today’s design engineers working to achieve industry disruption and evolution? For answers to these and other pertinent questions, read this white paper. Download Now
eBook - Rethink Your PLM
A lot has changed since the 90s. You don't surf the Web using dial-up anymore, so why are you still using a legacy PLM solution that's blocking your ability to innovate? To develop and launch products today, you need a flexible, cloud-based PLM, not a solution that's stuck in the past. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close