I moved in fall of 2010 and now live in a flood zone / high water table area. The yard is mostly flat except for a very slight hill in the middle of the yard. With a very heavy rain, it has the potential to flood and then stay saturated for weeks at a time. I attached a picture of a flood in Feb 2011. The water stood about 8 inches high and it took 3-4 weeks for it to drain away. We had ducks move in during that time!
Our first reaction to this flood was that all that standing water was a bad thing and we needed to make it go away. We hand dug a small trench (nothing fancy) to allow the water to drain away faster. Now we get puddles that dry up in 3-4 days in the outskirts of the lawn (all 4 sides, with the center of the yard still being the highest and now hosting a raised vegetable garden). Even a small amount of rain causes the yard to be quite soggy and muddy, even if you can't see obvious standing water.
This was all pre-permaculture discovery. Now, I've been watching some permaculture videos on youtube, especially Geoff Lawton's work, and I'm wondering if there's a more reasonable compromise for an area at risk of this flooding. The water soaks into the ground eventually, just very slowly. Am I messing with the water system too much by draining it away with a trench?
The flooding also renders half the yard unusable / unplantable (as far as I know) because I can't find any plants that can stand being flooded for one month out of the year, and then experience dry conditions later in the summer. I do not yet have rain barrels in place but I wonder how much they would decrease the flood risk? Swales seem to be for slopes, not for flat land, but can swales be used in this kind of situation?
It now seems ludicrous that I'm sending the water back to the city when, if I could hang onto it somehow, I'd be able to use it to water my veggies. Any suggestions? Thanks.
You might want to try berms and basins. You can dig out areas for the water to pool and build up other areas in which to plant vegetables. You might consider making the elevated areas quite tall hugelkultur. The basins can be used to grow water-tolerant plants like cattails and cannas.
my solution would be to dig down in some areas. these become seasonal ponds, wet basins and the soil moved stays in the backyard to make high spots, so when it does flood, the crowns and most of the root systems are above ground. while their feet(lower roots) are nice and wet.
this also gives you opportunity to plant more species of plants.
The ultimate goal of farming is not the growing of crops, but the cultivation and perfection of human beings. - Masanobu Fukuoka
it does appear that in the photo the water seems to be deeper at the far end right hand side..I would dig a pond there..as deep as possible (if that isn't where your drainfield is)..and make sure that you have at least one side that slopes gently so any critter that goes in can climb out..probably best to put the shallow end on the sides leading away from the fencing..and put an overflow in a place where it can go out safely..preferably under the fence if it isn't a problem on the other side.
use the soil from the dig to raise the areas around the pond gently being careful to not dam the water from reaching the pond..so move the soil quite a ways out into the yard..and contour everything toward the pond itself..if you have some organic material..bury it UNDER the soil you remove from the pond into the berm/bank areas to form a somewhat hugelkulture area..and have a path toward your house that drains naturally toward the pond..
if the ground is clay (likely) the pond should hold water for most of the year, and should refill with rainfall..try to get the center or far edge of the pond at least 6' deep so it is deep enough to put in some fish..and toss in a water lily or two..
it will be beautiful..if you want to you can add a pump/filter or a solar waterfall..and then it will even draw more critters and it will help to aerate the pond..
I would try to go at least 10 x 10 or larger if you can..and really you gotta have that gentle slope on one side.
we have a super high water table here and we still do get a little lowlying flooding, but most everything here drains quickly into our pond..see my address for blog and click on the pond building threads.
Bloom where you are planted.
We're actually in a very similar situation here in Central Ohio. High water table, very clay heavy soil, and a property that abuts a swampy creek area that accepts runoff from a lot of land in the area and floods for significant periods during wet seasons.
I was just discussing these issues with Braden Trauth (OM Valley Permaculture) during a 2-day presentation this past weekend. So much of traditional permaculture's approach to water issues seems to be centered on a drier climate where the focus is capturing and utilizing water as opposed to dealing with massive seasonal inputs of it.
I've been slowly compiling an expansive list of edible/useful species that can be reasonably expected to perform well in soggy circumstances. I'd love to compare notes with you.
Mosquitoes can be a HUGE issue here and I'd like whatever steps I take to help address that issue as well.
One thing I see that seems to be contributing to your problem is that you have those bricks around what appears to be the entire perimeter of your fenced in area. Also, your fence planks are way too tightly rowed. you need to space them enough that air wind rather and water can move through it basically created with looks like a pool take those bricks the line the bottom of your fence row stack them all up somewhere for a later suggestion. I have worked since the age of 13 in the asphalt materials industry Lime stone aggregates base rock etc., water requires only 2% slope no matter the size or distance in order to shed off a surface properly. As others have suggested, dig out your own retention pond somewhere nearby what you also should do is rent a motor grader or just hand huff it(manual labor) we need to create a High Point crown which Is perpendicular to where the waters natural run off direction is.If you were to view your land from an aerial shot looking straight down it would be basically a T where are the top of the T is your line of crown High center and the down of the T is the direction of the water: you will need some tall wooden stakes a flat laser or just a simple string line level will do and a measuring stick that is tall enough I.e. several feet to be able to measure from the ground to your string line. Thinn as tightly as you can get it without snapping or pulling your steaks out put two steaks in the furthest corners from each other of your lot stretch that string line across them both and then get it perfectly level so you can then accurately measure the natural slope in your lot. That’s the bulk of it.
Diego Footer on Permaculture Based Homesteads - from the Eat Your Dirt Summit