Catch Basin Freezng 2

[rwalsh]

I am involved with a project where a catch basin is being installed and the pipes inlet and discharge pipes will be above the winter frost level and I have been told that the ground will still be warm enough around the catch basin and that any water that stays in it throughout the winter will not really freeze. The inlet and outlet pipes will be pitched so they will be void of water. Will the catch basin water freeze or not. This project is located on a private road in Maine and there will not be a lot of water flow throughout most of the winter unless we get a warm spell and a lot or rain prior to the spring thaw. I expect that the area around the catch basin will freeze but I have been told that it will not and that does not make sense to me. I am looking for input and experience with this. TY

 

[cvg]

if the inlet and outlet pipes are sloped, than how will any significant amount of water ever be trapped in the catch basin?

 

[msquared48]

If the bottom ov the CB is above the frost line, I would be worried about frost heave of the whole CB, affecting the slopes and connections of the pipes too.

Mike McCann
MMC Engineering

 

[rwalsh]

The existing UG work has never been affected by frost and that is probably because the ground is almost all sand and glacial till so it drains very easily.

Also, the inlet and discharge pipes are above the bottom and that is why I am concerned about the freezing.

 

[cvg]

so your sump is full of ice, the catch basin will still allow water to flow out. It just won't trap any sediment.

 

[msquared48]

But the ice may expand, breaking the sides of the CB. Better to fill the bottom with concrete, similar to a sewer MH connection.

Mike McCann
MMC Engineering

 

[cvg]

ice will expand in the direction of least resistance which will be upwards. But I do agree, manholes and catch basins around here do not have a sump and are grouted to drain.

 

[rwalsh]

Will the ground stay warm enough to prevent freezing of the bottom of the catch basin? I believe it will not.

 

[cvg]

its not the ground to be worried about, it is the freezing air that circulates through your storm drain. as long as the catch basin continues to drain and the expansion of ice does not break the concrete apart, who cares if it is frozen?

 

[rwalsh]

Just trying to answer the one question I was not sure of - you know how it is.... word of mouth between people who do not do engineering but says that so and so says so ....and that is all they know ......

Appreciate all of the input .....

 

[civilman72]

I live in a VERY cold region of Colorado, so here's how I see it...

When the air temp is below freezing, generally speaking no water is moving or melting - on the ground or in the pipes. When it's spring, and snowmelt is starting, the air is generally above freezing, so the air in the storm sewer is also above freezing and generally the snowmelt will travel through the inlets and pipes OK. But you will see this same water freezing (at least around here) at night. It's warm enough in the day for things to melt and move, but at night the temps drop below freezing and the water that was moving during the day freezes on the ground, in the inlet grates, the inlet sump and the storm pipes.

Maintenance guys around here spend a lot of time steaming out the culverts and sometimes the storm sewer systems. It should be noted that steaming out a culvert (open on both ends) is a lot easier than a storm sewer system. I've been designing drainage infrastructure around here for almost 15 years, and I avoid storm sewer systems as much as possible. Keeping the freezing water on the ground is a lot easier to deal with then sending it into a closed system like a storm sewer.

But sometimes storm sewer is necessary, and the freezing problems is something you just have to deal with, unless someone can come up with a new idea (us nerdy engineers up here always joke about creating an "atomic evaporator"). On another note, I have yet to see a concrete inlet break due to freezing, but all of the inlets we install are pre-fabricated inlets with concrete bottoms.

Good luck.

 

[rwalsh]

Thanks for the note .... what you described is what I expected based on my engineering experience as well... that it will freeze during cold time and if the pitch is not great enough then the water will not drain from the pipes and the water will freeze in the pipes....and even if the pitch is high that there may be times that the pipe will freeze if the air temperature is extremely cold and preventing water/slush to flow quickly.

The system is collecting overflow water from a "wetlands of significance" - into a perforated catch basin (#1) lined with crushed stone for drainage - piped under the road (we cannot raise the elevation of the road) and connects to another perforated catch basin (#2) lined with crushed stone for drainage - and then is piped to a third catch basin (already installed by a land owner) on the same side of the road as catch basin #2 and then the water will discharge that landowners catch basin (#3) and flow through 190' of 12" underground ribbed pipe to a rip-rap filtration area before entering a lake. (The water discharge has been approved by our Department of Environmental Protection).

I had been told that the water in the catch basins would not freeze because of the warmth of the earth but as I indicated earlier that did not make any sense since frost/ground freezing should follow the contour of the land regardless of the depression caused by the depth of the catch basin.

Thanks again for all of the inputs........