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backyard drainage

Posted by Posierosie 7/Washington Dc (My Page) on
Sat, Jan 11, 14 at 11:27

Hi everyone,

I have been thinking of ways to manage my backyard. All the water from my neighbors front and backyard goes into mine from the left. It then travels across my yard, gathers in bumps (we attempted to fill a few in - hence brown spots) and then overflows to our neighbor to our back right. I am a bit concerned about wetness against the foundation, but as our basement is mostly above ground in the back, I think it should be fine. My major concern is that my backyard is marshy and we get tons of mosquitoes in the summer.

I have been thinking of putting two dry wells in my backyard to bring the water that is sitting at the surface underground and connecting the runnoff from my gutters with underground pipes. I was also thinking of putting French drains under the swale to help absorb the runoff. I will post a few pictures. It is pouring and you can get a good idea of the layout of my yard from all the pools.


Follow-Up Postings:

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RE: backyard drainage

Yes. Please post pictures that try to show overall conditions and general flow. I'm having a negative reaction to some of the solutions that you propose, thinking that certain things will backfire and possibly create more problems instead of lessening the ones you already have. That could be a lot of wasted effort.


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RE: backyard drainage

If the soil's not draining surface water it's probably not going to perc water in a drywell. It doesn't take much of a storm event to fill a drywell, especially with drainage coming from the neighbor. You may just end up with a perpetually full underground reservoir with a still-wet yard above it, only with fewer dollars in the bank.


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RE: backyard drainage

Panoramic picture to see water flowing


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Regular (non-composite) of the whole backyard


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RE: backyard drainage

Left side of the yard detail


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RE: backyard drainage

Right side of the yard detail.

All these pools breed mosquitoes in the summer who can use ephemeral pools to hatch eggs. I would want to keep the ability of the water to continue to flow above ground especially in big storms as I understand underground water containers cannot hold big storms and above ground water flows need to exist. I just want to have it dry quicker in smaller rain falls.

If French drains/dry wells are a waste of $$ and time, have I no other options? Are there certain thirsty plants I could plant? Alternatives are welcome. :)


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RE: backyard drainage

Having this water flow across your yard in a rain is not abnormal, but the existence of pools indicate that the grade is not smooth enough and needs tweaking. It looks like you might create a slightly more pronounced swale, draining from left to right where the predominant flow already exists. In order to figure out what to do, you'd need to know what the grades are where the water enters and where it leaves your property at the swale, in order to know what kind of flow the swale may have. Hopefully, it is at least about one foot of differential. (Find out the difference with an inexpensive line level on a taught string. You'd also need to know the overall length of this span. All the soil uphill from the swale, toward the house, should be graded smooth in order to get rid of the water-holding depressions. If there are paved areas adjacent to the house, there shouldn't be any areas adjacent to it where soil is higher than the pavement and keeps water from leaving the pavement. Your overall goal is to keep water moving and prevent it from being retained within any depressions. It doesn't matter how much comes onto your property as long as it will keep moving. Putting some of it underground in a pipe or gravel trough as it travels through would only insist that some of it stays ... which is no advantage to you whatsoever. As Marcinde says, it would fill up quickly. And you'd be stuck with an in-the-way underground thing. Surely, it would impede some future project.

If it was my yard, I'd make my own line level calculations about the swale and calculations showing how much slope differential exists from swale to property along back of house, which you would take at intervals of every few feet. ... in order to make sure that it will all work out before any digging starts. (doing your own grading plan.) Then I would contact a paver installation contractor and see if he has someone on his crew that can do precision grading with a Bobcat. Experienced guys who are used to doing prep for pavers work to tight tolerances and do a good job of achieving smoothness. They could probably take care of all the problems in 2-4 hours, just by moving the dirt around to a better configuration. I suspect that you might have small issues at the property line, because you must meet the grade that's there, or coordinate work with the adjacent property owners. The former is preferable, but sometimes the latter can improve the conditions for everyone concerned.


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RE: backyard drainage

Wow.

I did a design for a client with what appears to be a very similar backyard about 6-7 years ago. I laid out a 10' grid and spent 90 minutes tromping through ankle-deep muck shooting grades to the nearest 1/4". When I got back to the house and entered all the data it was clear - there was nowhere for the water to go off the property.

So I called a soil engineer to come out and see if we could do a drywell or big honking infiltration trench or something. He turned the corner at the garage, took one look at the yard, and burst out laughing and said "there's nothing I can do here, good luck."

So what did we do? We brought in a good bit of fill and then decided what corner of the yard they were willing to sacrifice. We raised the portion of the yard they wanted to use and pushed the water to the side they were ok with losing. They've been happy with the solution, and have done a rain garden in the bog. They do something to control the mosquitoes but I don't ask what. I probably don't want to know.

Yard and I tend to disagree on what's reasonable for a homeowner to tackle, but I'm sorry. To me this is like taking my 6-year-old niece straight from her EZ Bake Oven to preparing Bananas Foster tableside for Kim Jong Un. The stakes are pretty high and it ain't simple.


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RE: backyard drainage

Thank you both for your input. It seems like my grand idea of putting the water underground might be a waste of time and money. Well, that is fine. It is livable and not flooding my basement.

I am thinking that I might try to divert two of my downspouts to the front to drain into the street. It might help a bit.... I would need to see if there are any considerations for it as far as the city is concerned.

Maybe I can try to get a deal for my neighbor so their front downspouts are not facing backwards as well...... Probably wont happen as luckily for them, the water is my problem not theirs.

We are planning on having our cracked, water logged patio replaced and enlarged in 2-3 years so I might wait until then to put into place Yaardvark's suggestions. In other news, hoping for a good tax return this year to buy one of those fancy propane mosquito traps. It seems that might be an appropriate purchase when living on a bog. :)


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RE: backyard drainage

I am under the impression that there is slope and this is fresh rain. If that's the case the primary objective is NOT to retain any of the water that's passing through (in surface depressions.) If it's flatter than I think, you'll need more help, which is why I remind: you'll need to know the entry and exit elevations of the "river."

This post was edited by Yardvaark on Mon, Jan 13, 14 at 16:01


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RE: backyard drainage

I agree with the others that re-grading is a must to address some of that pooling water. However, I think you need to figure out a way to avoid that much water flowing across your yard, if you ever have hopes for a lawn. That much water will erode all of your topsoil in a hurry, making a quality lawn impossible. Here is what I would do in steps of order:

1. Re-route that back downspout asap. I can see in the panoramic that it is adding a lot of water to the problem.

2. Regrade - Maybe just DIY to start.

2. French drain along that fence line, if you have a location you can pipe the water too. Nothing too fancy, maybe a yard inlet at the surface and then you could use River Rock, like: French Drain/RiverRock. Even if you don't have a downward slope to route it, you could test out just filling a channel all along the fence line with several feet of gravel.

3. Dig a hole 1ft x 1ft. Fill with water, let it fully drain. Fill it again and time how long it takes to drain. Between 2-4 hours is ideal, over that and you have a poor drainage in your soil. This can be fixed by adding organic matter, simply top dressed or maybe in the form of "Compost Tea" since topdressing could just be washed away by the river...

4. Hydrophobic Soil. This is a condition where the soil is repelling the water and not absorbing it correctly. Organic matter, core aeration, liquid aeration, and even baby shampoo can be sprayed on the lawn to improve this condition.

5. Finally, I would think about trees, plants, that would thrive in your landscape. Being a huge fan of conifers, I would recommend bald cypress. They come in many different variety's and thrive and wet/soggy conditions. The two visible in the attached image are:
- Taxodium distichum 'Peve Minaret'
- Taxodium distichum 'Cascade Falls'

This post was edited by SC77 on Sun, Jan 12, 14 at 22:03


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RE: backyard drainage

Baby shampoo?


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RE: backyard drainage

  • Posted by SC77 6b (My Page) on
    Mon, Jan 13, 14 at 10:02

Haha...yes, it's true. That's everyone's initial response, but for whatever reason, very mild shampoo (typically cheap walmart brand baby shampoo) seems to work well as a surfactant/wetting agent. I'm not sure of the science behind it, but you can check out the Organic lawn care forum and see how much discussion revolves around this idea.

Some feel that doing this can actually replace the need to core aerate. I disagree, I believe the activities serve to separate purposes. However, there does seem to be clear evidence that mild shampoo sprayed at about 3 ounces per 1,000 square feet seems to work. Of course, if you have the $$ and don't care about organics, you could just by a premixed surfactant/wetting agent.

Here is a link that might be useful: Organic Lawn Care Forum - One of many shampoo/wetting agent discussions


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RE: backyard drainage

I've seen surfactants recommended for dry spots in the lawn. I think we're talking about two different goals here. A wetting agent will allow the water to penetrate to a shallow depth, accessible to grass roots (primarily). I don't see any way possible for it to move all that water down to an underground aquifer that may or may not exist. I'd wager that if the OP sticks a shovel in the soil when it looks like this, there will be a huge wet sucking sound and the removed soil will be saturated the whole length of the spade.

Here is a link that might be useful: science


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RE: backyard drainage

  • Posted by SC77 6b (My Page) on
    Mon, Jan 13, 14 at 13:06

You could be right, only way to know is for the OP to dig a 1x1 hole and see what the soil composition is under the surface. I had an issue with surface water in my backyard and it had nothing to do with the soil composition. It was the surface repelling the water, meaning that if you stuck a shovel in the ground it was bone dry, but there was pooling at the surface. Applying a surfactants allowed the water to get down to the fast draining soil below.

The link you provided explains the situation perfectly. It's like having a wax coating on the surface, nothing can penetrate it. So it doesn't matter if you have nice, fast draining, sandy soil below, you will get temporary pooling and runoff when it rains hard. If the OP finds that its not surface tension, but actually slow draining, clay soil, all hope is still not lost. You can improve that situation by adding Organic matter to the soil. It won't happen overnight though, it took me about 2 or 3 seasons of adding compost, coffee grounds, ect to increase my OM levels from 3% to about 11%. Core aeration is nice too because they you can get OM matter, fertilizers, ect deeper to the roots. Same thing with Compost Tea.


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what about mosquito 'dunks' for standing water.?


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@sc77 ... other than by retaining some of it (which is not necessarily and advantage unless one wishes to manage and use it) how would it be possible to lessen some of the water flowing across the yard? Even if rerouting the downspout, it's going to end up in the same pool. It's not likely it could be redirected to another drainage basin. Experimenting with a rock filled french drain seems like a major effort when it's not likely (unless it was enormous) that it could absorb much of the water that nature delivers. And the rock trench stands a good change of being in the way of other later-to-come landscape features.I disagree that a lot of water flowing across the surface is going to destroy whatever plantings. One must find the appropriate plantings for the conditions and there are plenty of situations where water flow like this across lawns during heavy rains. Sandbars in the middle of rivers are sometimes covered with grass, and there's grass here. It just looks nasty from winter.


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RE: backyard drainage

Work on the problems redirecting downspout water discharge first. Then study the situation again. Yes, as has been mentioned, spraying the yard every other month with a surfactant will be helpful. My two favorite surfactants are baby shampoo or any of the Method dish washing liquids sold at Target. I first proposed the use of surfactants back in the early days of GW and it took about a year of writing to convince others that the idea has merit. Suggest trying it.


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RE: backyard drainage

Looks like a place with A LOT of potential. I would really work with the landscape and just let it be. The first thing I thought of was bald cypress, taxodium distichum which would love the wet conditions, but it'd be better to look for natives which will do better. You should try finding a more central location to concentrate the water in one spot. Maybe by digging a bit in the center you could divert the water to this area. You could then surround this with natives and maybe some rocks for a natural landscape. I'm attaching a picture from a magazine I have which has what appears to be dogwoods and azaleas as well as some wetland plants which would do great in your area.

This post was edited by ricardomartin95 on Mon, Jan 13, 14 at 23:53


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RE: backyard drainage

Yardvaark, the OP said she could route that back downspout around the house, allowing the water to run into the street seawer system. That would indeed remove it from any basin on the property. Thats a BIG win, with little effort. Typical 1200sq roof runs off 700 gallons of rain durong a moderate storm.

Take a closer look at the panoramic and notice the flow of water running out that back gutter, right into the center of the backyard.

French drains pipped to the sewer could handle that volume of water without issue.

Finally, tall wildgrass on a sandbar is vastly different than residential turf. I didnt say the OP couldn't grow any grass. I said it wont be possible to grow a quality lawn because all the topsoil will br erroded and its too wet for grass to trive.

I would never tolerate flowing water and mosquitos in my yard. I outlined the steps I would take to fix the issue, not just accept it. Still, the property may always be damp, thus thr reason i suggested conifers that trive in that environment.


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RE: backyard drainage

What I'm seeing is an older development, most likely put in when a wink and a nod were what the developer gave the building office, not a grading and drainage plan. If you look at the right property line, there's a barely perceptible dip where water is coming through the fence. On the left it's more pronounced (likely 6-12") and then that ponding has a small channel cutting across the neighbor's yard and out the neighbor's back fenceline to... where? Hard to tell but it's not moving water well. The meandering course of the swale makes me think it happened by accident of grading and settling, not intentionally at construction of the neighborhood.

Look at the pic with the wheelbarrow in it - that whole patch of yard is really flat. Spraying Jerry Baker's magical home remedy stuff isn't going to change the simple fact that water is coming into this property from multiple points quicker than it can exit the property and the soils are saturated. Yes, diverting downspouts is worth doing, but this doesn't look like a neighborhood of 5000 sq ft + homes so it's not going to totally solve the issue either.

To the OP, you can either spin your wheels with buying cases of shampoo or pushing mud around in different directions or burying perforated pipes to collect mud, or you can call a local pro to at least come out and take a look. That's the direction I'd recommend.


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RE: backyard drainage

Agreed, there are flat parts of the yard. There are depressions. But viewing the overall scene shows that there is downhill slope from left to right running through the backyard (and the entire neighborhood.) The pictures also show that there is substantial (and adequate) elevation change from the house location to the likeliest potential swale location. The pictures do not show that the elevations are likely to be a problem. I'm not in opposition to a suggestion that the OP consult with a professional. But the OP is here, I think, as all seem to be, to advance their own thinking, even if they call in a pro.

If the OP says they will reroute a backyard downspout to the front yard, it's not likely that they will be able to accomplish this when the overall drainage is flowing toward the back. One cannot reasonably fight the overall direction of flow ... especially if it is the entire neighborhood. it makes much more sense to work WITH it. If the overall flow is toward the back and one routes a downspout to the front ... where will that water run once it leaves the pipe? The problem here is that flat spots don't move water on through the yard quickly enough. It is compounded because there are depressions that retain water and don't move it on at all! Regrading (probably not even very intensive regrading) would solve all of these problems.

Regarding piping a french drain to a sewer ... where is this sewer? I can't imagine that a storm sewer is located conveniently (and at the correct elevation) so as to make this possible.


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RE: backyard drainage

Hi,

Thank you for all your posts. It is so helpful and I am grateful you have taken the time from your day. I will try address some of the questions. I will have to do the water drainage test as suggested by SC77. My intuition is that it drains okay. The soil has a heavy clay component but is brown and rich. I do not feel it is hydrophobic as the ground stays wet for a long time. However, I am more than happy to be wrong. The grass is not happy at all and is filled with moss and weeds.

For the pictures, it was really pouring at that time and I thought it gave a good illustration of my concerns. Water is flowing across my yard from left to right and exiting into my neighbor's yard at the far right. The downspout you see in the picture would be very difficult to reroute. I have two others at the left side of the picture that you cannot see that would be better candidates.

The front of my home has the yard sloping gently towards the road. I could bury a pipe and redirect the two downspouts that are currently contributing to the pool on the far left of the picture towards the road. The is no storm drain per se, just the gutter of the road which lesds towards a drain farther down off my property.

In the meantime, I might get a 10' pipe and extend the downspout you do see further from the house. I would hope it might allow that 10' to be drier closer to the house.

So, my Spring project is a DIY grading mostly to fill in local impressions & reroute some of the downspouts. I will also test my soil to see the absorption rate and treat with surfactants if needed. Then, when we replace our current patio in a few years, we will readjust with the help of a professional. I would go the professional route faster but we are first time homeowners with quite a laundry list of improvements and limited means.

Have I missed anything?


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I might start thinking strongly of wetland gardening potential. :)


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RE: backyard drainage

  • Posted by jcalhoun 8b Mobile County AL (My Page) on
    Sun, Jan 26, 14 at 11:34

A buddy had a similar problem. He had a driveway contractor dig a slope for a cement driveway going to his back yard at enough pitch that the water collected in the middle of the new driveway. The driveway also has wingwalls to collect and push the water to the street. Basically it's a big cement gutter that goes to the street but level enough to drive on.

He then hauled in soil to slope the yard and fill the low spots. He also raised the yard around the perimeter of the house.

This post was edited by jcalhoun on Sun, Jan 26, 14 at 11:37


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RE: backyard drainage

  • Posted by jcalhoun 8b Mobile County AL (My Page) on
    Sun, Jan 26, 14 at 11:58

For what it's worth, DO NOT consider draining the storm water into your sanitary sewer lateral.

1. It's illegal.

2. You can overload the lateral and get a sewage back up into your house. Have seen it a few times.


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RE: backyard drainage

Dear JCalhoun,

Thank you for your thoughts and advice.

I was thinking of directing some of the flow to the street which would then presumably flow into a storm drain down the hill and be taken away by the storm drainage lateral rather than the sewer lateral. Is this still illegal? I see a few people in the neighborhood with a similar set up.

I wish I could extend my driveway like your friend. The yard goes down one story as the front yard transitions to the backyard (my main floor is at the same level as the front yard, but the house looks like two stories from the back as we have a walk out basement).

I don't mind a wet yard per se as we do not see any water issues with the basement. I just feel the backyard is not the playground we envisioned as the grass wont grow and there are so many mosquitoes.

I am crossing my fingers for a good tax return as I am planning on trying one of those propane mosquito traps. I lean towards more natural solutions so throwing mosquito granules every week or spraying with some type of insect repellant is concerning with two very young kids. I like the misquito dunk idea but have you seen the warnings on the package? Eek! We found spraying with cedar oil worked really well, but it smells, you need a lot of oil which is $$, and you need to repeat often. I will try to let you guys know if the propane trap works for us.

This post was edited by Posierosie on Sun, Jan 26, 14 at 22:15


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RE: backyard drainage

"I just feel the backyard is not the playground we envisioned as the grass wont grow ..."

It's not very likely that water washing across the yard during a rain is the original cause of the grass not growing well. If lawn grass declines beyond a certain point (for whatever reason) routine care and kindness is unlikely to bring it back. One would need to reinstall, but NOT BEFORE determining the cause of its decline.

Statistically speaking, the most common cause of lawn decline is lack of sufficient sunlight from ever-enlarging trees. (I see large trees in the vicinity and the lawn dips back into the tree area so it's a potential issue here.) Sometimes, the lower limbs of trees can be removed to let more light reach the ground. Sometimes whole trees need to be removed. (In certain low light areas, it's best to forget about grass and use groundcover instead.) The next likely reason is lack of sufficient water during the hot, dry period. The next reason is recurring wear and tear. Then, fertility starvation, pH & lack of weed removal. (Weeds are competition for nutrients, light & space.)

It's possible that the lawn suffers from multiple conditions. One must examine its history. Once lawn disappears then topsoil may wash. That becomes another condition that must be resolved before seeding or sodding is undertaken


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RE: backyard drainage

for whatever reason I just now noticed your first post says DC. Are you in the District itself? A lot of the properties are sitting on marine clay, which is not going to drain (I service VA/DC/MD so I've fought with that). If you're even considering pushing water to the gutter or a drain, I'd recommend either talking to the city or a contractor well versed in dealing with the city first. We're doing a job out by American University and DC doesn't play around. The building dept people are angry and want your money.


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RE: backyard drainage

  • Posted by jcalhoun 8b Mobile County AL (My Page) on
    Mon, Jan 27, 14 at 11:56

Posie,

Having the storm water running off of your yard to the street is the preferred method. That is why there are gutters in the street to collect it.

Maybe you can do something similar to a lateral by installing a 4 or maybe 6 inch pvc pipe that would run from the lowest corner of the backyard to the edge of the property line in your front yard. With the correct amount of fall from the back to the front the water would drain to the street and you won't need pumps, wells, or french drains. Just a box and screen in the back where you can keep the limbs and trash out and a clean out stack every 30 feet or so in case you need to snake it out. Maybe a splash block on the front yard end so it doesn't wash away the grass as bad.

The back yard would still need to have some soil brought in and graded to make the storm water flow to the collection point.

You would need to get somebody with a transet to shoot the grade to verify if the back yard is sufficiently higher than the street.


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RE: backyard drainage

Thank you all for your contributions. You have given me quite a bit to think about!

Yardvark, you are so right about the lawn. We had two trees damaged by the derecho that we took out and I did a soil analysis that said I needed nitrogen. So, a portion of some of the issues have been addressed. I will be reseeding and fertilizing once I have filled in some of the holes and redirected some spouts.

Marcinde, it is great to hear from a local! I am in MD just North of Kensington. Does the marine clay extend all the way up here? Is MD as difficult as DC?

Jcalhoun, you have given me an idea! I have been thinking of my property from the left side, but on the right side the slope from the front going down to the back is much less. It **might** be possible to redirect to the street that way. The street is higher then the backyard at all points, but my front yard is on a hill and so the difference is grade is less severe on the right than the left. You are right I would need someone to come in and quantify. If we go that route, I would expect some type of pump would be needed to work against the grade.


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RE: backyard drainage

I am kinda dealing with a similar situation at my new house although not nearly as bad, I have a lot more "yard" to work with. I was thinking I might dig a dry well and line it and then run a pipe from there to the front of the house where the road is. The road is lower than the back yard but there is a large berm in the way. I could drop a large sump pump into the container and have it pump out to the road whenever we get a heavy rain. I haven't done the jar soil test yet but I have planted a raspberry hedge and dug a small drainage ditch as a test and it sure feels like very heavy clay component to the soil. I don't want to burn electricity unless I have to nor do I want to invest in machinery, but a solid pipe might be less maintenance overall if you can collect in one central area and then pump from there. Smaller pipe like a 2 inch solid pipe would be less likely to get crushed and it shouldn't ever get sediment in it. You would want to keep a trap over the sump pit so you could keep that cleaned out regularly though. I haven't decided what I'm going to do with mine yet, but thought I would at least share this idea with you if you still haven't decided on what you are going to do.


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