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A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 11:43 am
by assateague
So, since it's been raining here for 6 days straight, I began pondering a question. It relates to a septic system drainfield. Bear with me.

It's very flat here. The water table is roughly 26 inches deep, so obviously it doesn't take much to get the ground saturated. You all know I'm cheap, and that relates to this question.

All drain fields fail at some point. Just a fact. I try to care for mine the best I can, because when it fails, I'm gonna be on the hook for a mound system, which ain't cheap at all. This is an old one, so it's grandfathered in as long as it is still working.

Right now, the drain field is under one of the horse pastures, about 150 feet away from a small drainage ditch on the edge of one of the field which borders the yard. For the past couple years, I've allowed a few small maple trees to grow up along the ditch, just to have a couple trees, and to provide a little shade for the horses in summer. Obviously they aren't very big right now, but are fairly old, since they've been getting cut down every year when the ditchbanks are cut.

But then today I was thinking. Am I hurting or helping the drain field? My concern isn't the roots, because they tend to grow straight down here, because of the water table and the fact that there are zero rocks. My concern is, I was going to cough up the money to have the ditch cleaned out (guys around here use excavators, and take them down to about 4 feet deep). I don't know if I should leave the trees or have them gone, too. My thought was, the root systems form the trees may suck up some groundwater, and therefore help the drainfield stay drier, but I don;t know if this is how trees work or not. Leaving them would reduce the amount of the ditch I could have cleaned out, and therefore reduce the amount of water it could draw off from under the yard/drainfield.

My question is, if i leave the trees, do you think they would offset the amount of water that WOULDN'T get carried away in the ditch if I had them gone too? This is what happens when I have too much time on my hands and get cooped up in the house.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 11:50 am
by jehler
How far is the septic tank from your well?

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 12:03 pm
by assateague
The tank? about 130 feet. The drain field? About 300 feet. Well's on the other side of the lot.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 2:00 pm
by Mornin Beef
That is a very shallow water table . That would lead to a shallower root system than you think. Tree Root systems require atmospheric oxygen and prolonged anaerobic conditions would lead to root dieback and lead to many other diseases. Considering a large mature oak would evapotranspire approx 40,000 gallons annually I would guess your maples average 5000 to 8000 maybe.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 2:04 pm
by huntfishnv
Hey MB what do you do for work, if you don't mind me asking? I remember you saying awhile back you could help people with flooding advice.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 2:06 pm
by Mornin Beef
I install mound septec systems.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 2:09 pm
by Flightstopper
huntfishnv wrote:Hey MB what do you do for work, if you don't mind me asking? I remember you saying awhile back you could help people with flooding advice.


He works for number two.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 2:10 pm
by huntfishnv
Flightstopper wrote:
huntfishnv wrote:Hey MB what do you do for work, if you don't mind me asking? I remember you saying awhile back you could help people with flooding advice.


He works for number two.


:lol:

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 2:48 pm
by Tomkat
Flightstopper wrote:
huntfishnv wrote:Hey MB what do you do for work, if you don't mind me asking? I remember you saying awhile back you could help people with flooding advice.


He works for number two.


Naw, he's full of crap

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 3:13 pm
by assateague
Mornin Beef wrote:That is a very shallow water table . That would lead to a shallower root system than you think. Tree Root systems require atmospheric oxygen and prolonged anaerobic conditions would lead to root dieback and lead to many other diseases. Considering a large mature oak would evapotranspire approx 40,000 gallons annually I would guess your maples average 5000 to 8000 maybe.


So do you think it'd be a wash or not? I knwo the roots are shallow, I just don;t worry about the roots interfering with the drainfield nearly as much as I worry about the ludicrous water table interfering with the drain field. Worse comes to worst, I'll be out there with a shovel and 4" PVC pipe at midnight trenching it directly into the ditch. Eff the police.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:01 pm
by Mornin Beef
So do you think it'd be a wash or not? I knwo the roots are shallow, I just don;t worry about the roots interfering with the drainfield nearly as much as I worry about the ludicrous water table interfering with the drain field. Worse comes to worst, I'll be out there with a shovel and 4" PVC pipe at midnight trenching it directly into the ditch. Eff the police.[/quote]
Getting a grade all or excavator in there will certainly make the water table droop a bit in the direct vicinty of the ditch creating a bit of sink for the immediate area. Personally I would have them work the ditchline and work around the trees the best they can especially if the horsies enjoy the shade. I would consider planting willows or some other tree species considering how much water they really intercept. Willows are free by the way. Just cut off some healthy branches while the mother tree is dormant and soak them in water and they ought to root just fine considering the water table is that close. One thing that worries me though is that if your water table is 26 inches and you trench to 4 foot your going to have a perennial stream in that ditchline afterwards.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:04 pm
by Mornin Beef
Let me think a lil bit

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:06 pm
by assateague
I would love to plant willows, but the leaves and new shoots are toxic to horses.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:10 pm
by jehler
assateague wrote:The tank? about 130 feet. The drain field? About 300 feet. Well's on the other side of the lot.
Reason I asked is allegedly I have seen some punch a few holes in the tank to help the drainfeild last a little longer

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:11 pm
by assateague
I've got a concrete tank. It'd be pleasant to try.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:12 pm
by assateague
I would not be beyond just running a pipe straight from the waste outlet into the ditch. Eff em.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:13 pm
by assateague
Someone may see a shit-covered guy at midnight in the side yard, furiously driving a digging bar into what appears to be a hole in the ground.

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 4:15 pm
by jehler
assateague wrote:I've got a concrete tank. It'd be pleasant to try.

Getting in the tank is a lot worse than actually drilling the holes

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 5:06 pm
by Eric Haynes
jehler wrote:
assateague wrote:I've got a concrete tank. It'd be pleasant to try.

Getting in the tank is a lot worse than actually drilling the holes


I take it that you too have been in a few. Last one I was in, whoever installed it, drilled holes into the concrete and instead of using TapCons, they decided drywall screws and silicone would do the trick. The screws rusted out and the wire fell in shorting out. Was a fun one. Amazing how corn sticks to concrete so well!

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 6:48 pm
by Mornin Beef
This first picture depicts the effect of deepening the ditch. The lateral effect has quite a bit to do with soil type. The sandier the soil more lateral effect you will have upon the watertable. The tighter the soil the less efffect upon the water table.

Image

Since your ditch is quite a distance from your septic it may have little effect unless you have very sandy soils.

I would think your best bet at lowering the water table in the direct vicinty would be to tile on either side of it to the ditch.
Image

Image

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 7:47 pm
by Bootlipkiller
My answer is keep the trees and shit in the yard!

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 7:49 pm
by Eric Haynes
assateague wrote:I would love to plant willows, but the leaves and new shoots are toxic to horses.


Cut the maples and burn them. Win Win

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 7:57 pm
by jarbo03
assateague wrote:Someone may see a shit-covered guy at midnight in the side yard, furiously driving a digging bar into what appears to be a hole in the ground.



Sent from my SPH-D710 using Tapatalk 2

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 8:00 pm
by Mornin Beef
:lol: :lol: :lol: :lol:

Re: A Physics Question (I Guess)

PostPosted: Thu Jan 17, 2013 9:11 pm
by assateague
Mornin Beef wrote:This first picture depicts the effect of deepening the ditch. The lateral effect has quite a bit to do with soil type. The sandier the soil more lateral effect you will have upon the watertable. The tighter the soil the less efffect upon the water table.

Image

Since your ditch is quite a distance from your septic it may have little effect unless you have very sandy soils.

I would think your best bet at lowering the water table in the direct vicinty would be to tile on either side of it to the ditch.
Image

Image


Thanks. The first one pretty much answered my question. I don't believe I could lower the water table more than an inch or so near the drainfield, so I guess I'm keeping the trees, and cleaning out most of the ditch, and keeping my fingers crossed. Since I pissed of the county health department a while back, they've already said they aren't going to issue a new permit for ANY septic when this one fails. But I'll just bootleg it when that happens, or dare them to stop me.

Re: A Physics Question (I Guess)

PostPosted: Fri Jan 18, 2013 7:23 am
by QH's Paw
Mornin Beef wrote:This first picture depicts the effect of deepening the ditch. The lateral effect has quite a bit to do with soil type. The sandier the soil more lateral effect you will have upon the watertable. The tighter the soil the less efffect upon the water table.

Image

Since your ditch is quite a distance from your septic it may have little effect unless you have very sandy soils.

I would think your best bet at lowering the water table in the direct vicinty would be to tile on either side of it to the ditch.
Image

Image

Are you talking drain curtain type setup. I think it's easier to buy the styrofoam netted material with perf pipe in the middle of it, rather than to bare the cost of drain rock or tilepipe and moving all that material too. You could do it yourself by renting a ditchwitch and laying the pipe yourself, with out involving a contractor. I don't know if it's allowed there but, it is recommended here.
They (the county) made me pump up hill into my pasture at my old place when I rebuilt the drain field. I had to had a pump and well next to my tank and the electrical to support it.They required me to place a rain curtain around the up hill and some side hill from the septic field. I had 375' of septicfield runs and almost 200' worth of drain curtain around it.

Something like this.
http://www.ndspro.com/drainage-systems/ ... nch-drain/

Mine was bigger, it had more material around it

Re: A Physics Question (I Guess)

PostPosted: Fri Jan 18, 2013 7:29 am
by QH's Paw
Assa, those people don't work on weekends. Just get a back hoe and fix or replace it over the weekend. If they give you grief just say you're punching test hole for a new well or perc holes and didn't know there was a field there.

Re: A Physics Question (I Guess)

PostPosted: Fri Jan 18, 2013 7:46 am
by assateague
It's not broken yet. Just planning for the future.

Technically (legally), you can go to the health department here in the county, say I need a new system, and I'm doing it myself- you design it. And they have to do it for you for free. And let you do it yourself, with the regular inspections. I only know of one person who has done this, and they were such dicks on the inspections that it almost wasn't worth it. Just flat out lying to him about stuff. I swear those guys are all getting kickbacks from the septic installers. It's perforated pipe and gravel, it ain't fucking rocket science.

Re: A Physics Question (I Guess)

PostPosted: Fri Jan 18, 2013 8:17 am
by QH's Paw
assateague wrote:It's not broken yet. Just planning for the future.

Technically (legally), you can go to the health department here in the county, say I need a new system, and I'm doing it myself- you design it. And they have to do it for you for free. And let you do it yourself, with the regular inspections. I only know of one person who has done this, and they were such dicks on the inspections that it almost wasn't worth it. Just flat out lying to him about stuff. I swear those guys are all getting kickbacks from the septic installers. It's perforated pipe and gravel, it ain't fucking rocket science.

For your septic field, infiltrators are way easier than building the old type.

Re: A Physics Question (I Guess)

PostPosted: Tue Jan 22, 2013 11:03 am
by Baysider
Assa I may or may not know a guy who doesnt mind adding lines and cutting off old lines to an existing sysyem. He prefers to work weekends when he inspectors are sitting on the sofa. I know he's done some work in MD in the past.