New Saturated Field

[camm80]

I wanted to collect some thoughts on my problem with my septic field. We just built a new house with a septic tank (1500 gallon) and a chamber system leach field (Infiltrator EQ36 - 7 - 72 foot laterals). We live in the Midwest and have bad clay soil. Most in my subdivision have aeration units which make use of the above ground discharge. This is now frowned upon by the county which is why I have this large septic system. We have used the system without problem since August 2007. Our area had 100 year record rainfall this March (8 inches) in which we had our first backup. Our field was saturated. We found that there is a pitch problem on the field surface slope which may of held rainwater on the field instead draining it to a low spot.

I had 2000 gallons pumped from the tank and another 1000 gallons backfed to the tank. I also had an excavator slope a line through the field and create a path for surface water to go to the ditch and not dam up like it was doing.

We ran for about two weeks, and now we are back to the saturation point. Septic installer dug a hole at the last finger lateral and 12 inches of water rose from the top of the chamber.

I am looking for ideas of solutions no matter how bad they could be. We just want something that will work.

Suggestion from my septic installer:
- Add another 3 lines to increase capacity (yet 3 more lines in crummy soil doesn't seem like it will fix the issue, just buy me more time).

My own thoughts:
- Can I convert to aeration so that I can above ground discharge excess capacity? I think this would be difficult to get approved by the county.
- Can I put a type of sand layer in to wick the water to a drainage ditch?
- Is this possibly just a problem from the record rainful and my drainage issue. It could be that my clay got soaked, and now it cannot dry out because it is always getting wet occasionally.

Thanks

[suemarkp]

Wow, 500' of Infiltrator drainfield and you're still backing up! Did anyone do a perk test and if so do you have that data? How large is your lot, and is there a way to get rid of surface water from around the perimeter of your drainfield (perhaps an area surrounding the whole field + 20' in each direction)? Does everyone (neighbors) have this problem? If so, the whole area is not a great place to build drainage. If not, you may be able to find a more suitable spot on your property.

If you can't get rid of the surface water by digging a moat around your drainfield and diverting it elsewhere, about all you can do is improve the soil you have so it drains better (e.g. tilling in sand, lime, and organic matter into the soil). But this only buys you so much, because this will eventually fill up too if what you've improved can't drain away (kind of like having a nice well perking drainfield installed in a very large swimming pool with no drain).

A mound solution may also work. You basically build a mound of dirt that perks at the correct rate. The water gets treated as it soaks through that mound of dirt. This will require a pump in your tank to trickle water into the mound. This mound may be rather large and ugly, and may not be allowed if you have a fundamental drainage problem. They also have alarms and pumps that require electricity, so you need a plan for what to do during a power failure.

Finally, if there are no drainfield solutions, then an aeration & sterilization system is about your only remaining choice. These just dump drinkable water into the ground when they are done with it. These are less preferred by health departments because of the pieces that can fail and they are a pain for you because of things that burn out or run out (sensors and UV lights or perhaps chlorine). They also have alarms and require electricity to work, so you have the same if not more power issues here.

[Fischer]

Sorry to hear about your situation. There's not much you can do with saturated soil, especially clay based. I would have to also say a mound system and allowing for gravity drains from your property would be your best bet.

Additional lines aren't going to help much. 1 inch of rain over a 1 acre lot figures out to be 33,000 gallons. Extra lines aren't going to help much. Get all the water out of there you can before anything else is tried.

Best of luck to you.

[pushkins]

Have you had a soil sample (core drill) done ?....if so just how deep does the clay go down ? There are solutions, provided that the clay isn't endlessly deep and for around $250 a core drill and analysis might be a good investment.

[camm80]

Thanks for all the posts. Hopefully I answer many of the questions here:

Answers:
The developer did a soil analysis back in 96 when he developped the land, and I had one done again before I built. They resulted the same thing. Basically did a 3 foot sample and it was mostly clay, if not all clay. I think part of the problem is that the soild anlysis was done in the summer months when the clay crumbled apart. They did say over the past 100 years we could see a gray line showing the water may have been present in that sample, but its hard to tell since the developer re-excavated the area in 1996. Based on that, the county had me put in a 500 foot infiltrator system with a curtain drain. The curtain drain my instlaler put in was nothing more then a perferated PVC pipe burried in the ground and running down to the drainage ditch.

Other neighbors are not having the problem because they have aeration units mostly and when they filled up they discharge out the above ground discharge tube. The county frowned on that system now, so they had me put in the standard septic.

I have an acre lot, but really not much space left for a "secondary system, and definitly not of that size or near it. The system would then have to be uphill from my current system which would involve pumps and then consequently flowing water back to my walkout area. I have geothermal pipes all over the ground too, which technically I could place lines over, but in case of problems with my geothermal I'd rather not. I have utility hell too since we have utilities coming to the house from every side of the house ,except the septic field side. So the spot it is at, is really it. I'll try to post a link to some lot pictures if it helps.



Current condition:
- I have two holes dug to the top of the last two laterals in the field. Water has been standing there between 8 - 12 inches and doesn't really go down much, so it appears that the clay is holding the water in the ground (surface is walkable and not muddy) and not allowing the water to flow out towards my ditch.

I have a thought that I could wick water away with a sand layer towards my drainage ditch 15-20 feet away. This would give the clay an escape point at saturation. Thoguhts?


Other Questions:
-Going to an aeration system, would still have the same water problem, right? I would only then just have a safety of the above ground discharge for overflow?

-Building a moat around the field... Would this just pull off water table (if any is present) and rain water flowing downhill towards the septic field?


I've read a lot about these mound systems. Question is how do they take that much water and get rid of it? Won't the water just seep back to the "surface" of my yard and then run out? In our area I have never seen those done so thats why I am asking. Will I have to put in a second tank to hold the water and "pump" water equally to each mound?

[camm80]

Picture of the area from May of last year. The slope is a lot less now on the front and towards my ditch in the front yard.
http://camitnetwork.com/house/wp-content/uploads/2007/05/p1010026.JPG

Here is the soil analysis from before. Only difference was the top layer of dirt was gone and the boring 1 is useless since it is outside my field area.
http://camitnetwork.com/soil.pdf

Another view of the area.
http://camitnetwork.com/house/wp-content/uploads/2007/03/p3280023.JPG

Since I have such a large field, it is yet more area to protect too. At some point I wonder if the larger field hurts things over helps.

[Fischer]

-Building a moat around the field... Would this just pull off water table (if any is present) and rain water flowing downhill towards the septic field?


I've read a lot about these mound systems. Question is how do they take that much water and get rid of it? Won't the water just seep back to the "surface" of my yard and then run out? In our area I have never seen those done so thats why I am asking. Will I have to put in a second tank to hold the water and "pump" water equally to each mound?[/QUOTE]


Moat would at least give the higher level a place to eventually drain off. Sloping to the moat would help.

The mound system is primarily used for soils that won't perk. Evaporation is the means of water removal. Now here's the situation that can plague a mound system. If you have a very cold winter with no snow cover, your mound system can freeze. In this situation you end of without a septic system till it thaws, so with that in mind (depending on how far North you are), a layer of straw in the fall is a very good idea.

You know yourself you're in a very bad spot. Your soil is bad to begin with. I'd contact a soils engineer in your area and ask about a system based on your problems. You already have the soils engineering done, so you are ahead of the game. You should be able to at least talk for a minimal charge so go with that. In my mind your going to have to go with some sort of a mound system, and it will have to be well taken care of. The engineer will have the calculations for your usage and what you'll need for soil. Make sure that you stipulate that you want it engineered for a 500 year flood. Seen too many 50 and 100 year floods in the last 5 years.

[suemarkp]

I don't know your water usage, but if you design for a typical house of 3-4 people (900 gal/day), with your low perk rates you need 1800 - 2000 square feet of drainfield. The infiltrator is 3' wide, so you have 1500 sq ft now.

But if your field is full of groundwater, adding more is pointless. If you can divert runoff from above via a moat around your field (and this moat should be about as deep as bottom of the infiltrator pipe), and drain the field via the moat, that may do it. Need to make sure the ends of the infiltrator aren't too close to the moat and just dumping directly into it (would be dumping raw septic water into the runoff ditch). I can't tell from your pictures if you have a low spot for this moat to drain to that will carry the water away. If it just a low spot, you'll end up with a lake. If it is still marginal after this, another 100 to 150 feet of infiltrator may help.

[camm80]

Thanks again to all.

I had another contractor come on site and look at my situation. He claims from my soil analysis that the high water table alone means I should have never of had a lateral field in that area. So if the ground was saturated underneath from water table, it obviously is not going to soak up effluent. His recommendations were to place an aeration tank off my septic tank, and run a new lateral with an above ground discharge. This claim is that this is my cheapest solution at this point because my lateral field will never work. Problem here if he is correct, every 20 gallons in means 20 gallons out the discharge, so I am talking about a lot of water draining off into the yard / ditch, running into other peoples properties.

I find it hard to believe that once I am past the spring, my lateral field wouldn't work at all anymore to abandon it. I also think I should truly find the water table by maybe digging a hole between laterals or at the end of my field and see how far down I go to water. Wouldn't that tell me if the water problem is from water table vs water in the chambers not being absorbed into the soil??

I do have some questionable things I am going to check that could be contributing to the problem too.
1. My drain tile from my house is also tied in and acting as my "curtain drain" piping. So the perforated pipe coming from my house tile system then is still perforated going all the way to my low point, wrapping the high side of my septic field. This was supposedly to catch water table coming up. I think my drain tile from my house (no sump pump, just form a drain tile system) should have used solid piping to the ditch to divert any water it collects to the ditch without possibly adding to my septic field. I also have one downspout tube that is discharging on the top of one of the laterals. That should have also just been run another 50 feet to the ditch.

So I am kind of at the point where I know there is other things possibly to fix, but not sure if they would be wasting my money and then requiring to go to aeration system anyways which will be costly.

The contractor's only other option was to utilize another area of my yard and put in a drip system, which he claimed would be 7k more on top of the aeration cost. That would then drip the effluent up my hill to another area of my yard.

As for the mound system, I still need decent surface soil and drain off for that right? They can't just build a big hill to solve all the problems? Most of what I read on them still require the surface to be somewhat permeable, but also that mound system involves bringing in dirt / sand, and having a pump like the drip system. In that case wouldn't I be better off with a drip system?

As for the other answers. We live in the St. Louis area with mild winters. It gets below freezing with maybe 10-20 inches of snow a year at max. Most snowfalls are few inches only and more commonly we get freezing rain.

I have a 4 bedroom house with 2.5 baths. There is only two adults and 1 child living in the house currently. Our largest water sources are our laundry machine (top load, but investing in a front load shortly), and bath tubs. We do baths for the kid, and we have a jacuzzi tub in the master bath that gets some use. We have a dishwasher we use a few times a week, and regular water usage as others have. New house so all low flow toilets and faucets. I do have a water softener but it drains about 20 gallons of water once a week at most.