# Outdoor Sump Pit



## LMcKee (Aug 7, 2009)

I have (had) a serious drainage problem in my backyard. (Runoff and an underground stream.) I dug a 1" deep, 1.5" wide, 140' long ditch across my backyard, up the side yard, out to the street. I ran into a depth problem with the gas line so I couldn't reach my desired 2.7" depth for gravity drainage. So I built a sump pit using plastic bins, drilled holes, surrounded by filter fabric. Everything is working fine, but I'm concerned about the amount of dirt and silt that is accumulating. I want this to be a permanent solution. Does anyone have experience with this? Does anyone know of a sump pit pump setup that is used outdoors in the ground?

Thanks!

Lauren


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## mpoulton (Jul 23, 2009)

LMcKee said:


> I have (had) a serious drainage problem in my backyard. (Runoff and an underground stream.) I dug a 1" deep, 1.5" wide, 140' long ditch across my backyard, up the side yard, out to the street. I ran into a depth problem with the gas line so I couldn't reach my desired 2.7" depth for gravity drainage. So I built a sump pit using plastic bins, drilled holes, surrounded by filter fabric. Everything is working fine, but I'm concerned about the amount of dirt and silt that is accumulating. I want this to be a permanent solution. Does anyone have experience with this? Does anyone know of a sump pit pump setup that is used outdoors in the ground?
> 
> Thanks!
> 
> Lauren


It sounds like what you built is a miniature drywell. Around here (Arizona), drywells are used all the time to handle stormwater. We don't get rain often, but when we do it's often torrential but only lasts a short time. So, instead of a storm sewer system, we use retention basins to hold all the runoff from a site, and drywells in the basins to dispose of all the water by draining it into the ground over a period of time. Drywells are typically 2-3' in diameter and 20-100' deep. Although the desert is full of fine silt and clay, we do nothing to prevent accumulation - it just isn't a big problem. Maybe if you make your pit deeper, it will have sufficient capacity to handle the silt without causing an issue.


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## LMcKee (Aug 7, 2009)

Thank you MPoulton. However, it looks like I forgot an important detail of my dilema - My pit is about 2.5 feet deep. The ditch runs into the pit. I have a large hard plastic bin with holes covered in filter fabric, then a 5 gallon drum with holes covered in filter fabric, then an industrial strength sump pump that pumps out the water that flows into the plastic bins. I am too low for this water to seep into the ground, hence the sump pump to the street. (I have had the county out to confirm it's okay to pump to the street because all of this water is rain runoff from the hill above my backyard and the underground stream running through my backyard.)

When there is a heavy downpour, a lot of water comes over the top of my bins into the area where the sump pump is. Otherwise, the water follows the ditch to the pit and gently seeps into the pit. The problem is, I am watching as this filter fabric is now struggling with the amount of silt accumulated so far. This solution has only been in the ground for 2 months. My soil does have a lot of clay in it.

Thanks!

Lauren


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## mpoulton (Jul 23, 2009)

LMcKee said:


> Thank you MPoulton. However, it looks like I forgot an important detail of my dilema - My pit is about 2.5 feet deep. The ditch runs into the pit. I have a large hard plastic bin with holes covered in filter fabric, then a 5 gallon drum with holes covered in filter fabric, then an industrial strength sump pump that pumps out the water that flows into the plastic bins. I am too low for this water to seep into the ground, hence the sump pump to the street. (I have had the county out to confirm it's okay to pump to the street because all of this water is rain runoff from the hill above my backyard and the underground stream running through my backyard.)
> 
> When there is a heavy downpour, a lot of water comes over the top of my bins into the area where the sump pump is. Otherwise, the water follows the ditch to the pit and gently seeps into the pit. The problem is, I am watching as this filter fabric is now struggling with the amount of silt accumulated so far. This solution has only been in the ground for 2 months. My soil does have a lot of clay in it.
> 
> ...


So the water flows through the filter fabric before it enters the bin that holds the pump? The reason for the fabric, then, is to remove silt before it reaches the pump? The problem is that the fabric is clogging with silt? I think you might be able to solve this by eliminating the fabric and using a "trash pump" that can handle solids. It will just pump the silt right on through.


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## LMcKee (Aug 7, 2009)

Yes, that is what the filter fabric is for. I used it so my pump would't get clogged. It's industrial strength, but can only handle a specific size and didn't want anything larger than that to enter the pit area. So, there are pumps out there that can handle large pieces? Is that what a trash pump is? If so, bonanza for me! Problem solved!!! Thanks MPoulton!!! I'll investigate that this weekend. Hey, do you have any recommendations on any one in particular?

Lauren


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## mpoulton (Jul 23, 2009)

LMcKee said:


> Yes, that is what the filter fabric is for. I used it so my pump would't get clogged. It's industrial strength, but can only handle a specific size and didn't want anything larger than that to enter the pit area. So, there are pumps out there that can handle large pieces? Is that what a trash pump is? If so, bonanza for me! Problem solved!!! Thanks MPoulton!!! I'll investigate that this weekend. Hey, do you have any recommendations on any one in particular?
> 
> Lauren


A "trash pump" or sewage pump should work. They are designed to handle solids, and have impellers that act sort of like a garbage disposal. Large rocks are bad for them, but you should be able to replace your fabric with a coarse screen and let the dirt go on through. Lowe's sells suitable pumps. Just be sure to get one that pumps fast enough to handle the water flow, and install it safely (GFCI protected, certainly). Some of these pumps do not come with built-in float switches, in which case you'll need to add one.


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## Aggie67 (Dec 20, 2008)

Be warned. Whatever solids or silt that gets pumped away is going to be deposited in your pit. You'll be moving soil from one spot to another.

I've got a similar issue in my backyard that I'm going to be fixing next week. Fortunately all I have to do is extend an existing underground drain system, not start from scratch. I dug a hole and put in a bucket/fabric/pump in the lowest part of my yard, and I'm pumping it through a garden hose to the nearest drain head about 15 feet away. The fix will be new pipe and a new drain box installed at the very lowest point.

Right now I can see some of my back yard soil in the street (my drain system discharges into the street at the curb). The silt fabric only holds back so much.


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## LMcKee (Aug 7, 2009)

Thanks MPoulton. I've already done a little checking and found one that has a float. I think all this will now work.

Hi Aggie67 - Thanks for the input, but I think you misunderstood. I'm pumping to the street, the pit catches the water from the ditch that is draining the excess runoff and underground stream. My ditch has corrugated tubing (wrapped in fabric filter) and the tubing is buried under gravel then river rock. I did this so my ditch will look like a natural stream. I didn't want to bury the tubing with sod just in case I need to repair it. And, it looks pretty cool, the stream flowing around my property. I am in the process of building two bridges over the stream ditch for added ambiance. So I'll be pumping all this directly into the storm drain in the street. Actually, I'm not too worried about my yard going down the drain. It doesn't appear to be that much, but just enough to cause the fabric filter around the pit bins to easily clog. I think a trash pump will do the trick. But I will keep my eye out for how much soil I loose throughout the year. Also, I think I have some design changes to make to the bins as well.

Thanks!

-- Lauren


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## erubash (May 12, 2010)

Did you ever figure this problem out and if so how!


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## AllanJ (Nov 24, 2007)

Could you put a 6 or so inch drainage pipe under the gas pipe crossing the drainage ditch path, and have gravity drainage all the way to the street?


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## erubash (May 12, 2010)

Little Giant makes a great pump for this. http://www.lgpc.com/Product/ItemDetail.aspx?ProductID=425 
If you get with the vertical float you will be in good shape! Works well form me I used to use fabric but now it's all free flow an very little problems.


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## LMcKee (Aug 7, 2009)

erubash said:


> Did you ever figure this problem out and if so how!


Sorry for taking so long to respond.

The ditch and sump pit work very well! I am using a trash pump so it can handle dirt and (very) small rocks that make their way to the sump pit.



AllanJ said:


> Could you put a 6 or so inch drainage pipe under the gas pipe crossing the drainage ditch path, and have gravity drainage all the way to the street?


Well, to do that I'd have to dig underneath the gas line, and then I'd have to know exactly where that line is. I accidentally put inches in my posting instead of feet. My ditch is 1 foot by 1.5 feet, not inch. With gradient, when I get to the gas line, I am at 2.7 feet. To dig underneath the line at 3.0 would be quite a challenge. Wish I could - would much rather do this by gravity, but I didn't want to chance blowing myself up by accidentally cutting the gas line with my shovel.


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## erubash (May 12, 2010)

What kind of pump is it if you don't mind me asking?

Make and Model!


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## LMcKee (Aug 7, 2009)

erubash said:


> What kind of pump is it if you don't mind me asking?
> 
> Make and Model!


Not sure - it's an old one my father had in his garage, but it's cast iron and a real workhorse. He's a civil engineer specializing in dewatering and happens to have a lot of equipment. I ran a check and the Bell & Gossett trash sump pump looks the closest to what I have. You have to be sure it can handle solids. My can handle up to 3/4" - the example one here can handle 3/8".

http://www.globalindustrial.com/p/p...mp-pump-0-33hp-115v-2-9-amps-plug-no-switch-2


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## johnddubau (Jun 10, 2010)

*question for lmckee*

I was wondering about the underground stream you mentioned in your backyard, could you describe what you know about it?


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## LMcKee (Aug 7, 2009)

*Underground Stream*



johnddubau said:


> I was wondering about the underground stream you mentioned in your backyard, could you describe what you know about it?


The stream is rather small, bubbles up in my yard for about two feet depositing a good amount of water then goes underground, bubbles up four houses down (about 150' away) and they have significant flooding in their yard year round, then goes underground, until it emerges in the field behind our houses in the form of a pond. County records show the area at the back edge of my yard as documented wetland. When there is a lot of rain or snow, the ground is too saturated from the stream I get severe flooding in the backyard. My ditch follows the stream along the backyard, then up the side of the house to the street. The water in the stream has a sulphur odor and porous soil characteristic of a wetland stream.


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