Living in a flood zone

Assuming one wants to move to a rather flood-prone area (for any varied reasons) and wants to improve his/her land to avoid sandbagging every spring, is there anything that is taught by permaculture concepts that could help?

So far, I'm thinking...

a) Digging ponds and/or ditches, using the soil to form a sort of dyke/soil fence around the property - disruptive, but only initially, result is a sort of microclimate and aquaculture potential.
b) Building up the soil - takes a looooooong time to build enough soil to raise the land
c) "Don't even think about moving into a flood plain, it'll give you grief the whole time you live there"

Comments?

BTW, I am thinking of the Red River Valley South of Winnipeg. They're already planning for a "best case scenario" equal to the very damaging flood of 2009, worst case the flood of '97.

A couple great references:

"Water for Every Farm" by PA Yeomans

"Rainwater Harvesting for Drylands and Beyond Volume 2" by Brad Lancaster.

I can't recommend both of these books highly enough.  The Yeomans is THE classic work about earth-shaping to manage floods and droughts.  The Lancaster book is more recent and more useful for smaller-scale endeavors.

http://www.yeomansplow.com.au/

http://www.harvestingrainwater.com/

I live in a flood-prone area (39 million gallons of run-off over my land per hour in flood) and I will say it is a BIG challenge.  It's shocking to see fences and trees knocked down in your backyard or your chickens nearly drowned from rising water.  And damage to structures and roads is expensive to repair.  So be aware of what you're getting into.  On the other hand extra water is a precious resource if you can afford to capture and use it.  So far, because of limited financial resources, I haven't been able to do much with flood mitigation and rainwater capture.

Any references for farms vulnerable to coastal flooding?  Salt water poses its own unique challenges.  As sea level rises I worry about this affecting more areas of my farm.  Should I saturate the soil prior to storm surge?  Building dikes is a possibility but once flood waters intrude it's most important to get that salt water off the land fast.  I'd love to know how other folks have dealt with this.

In Jordan, Geoff Lawton's earth shaping and mulching seemed to counteract salt very quickly.  http://www.youtube.com/watch?v=43RDIochym0 ; But I should think avoiding salt intrusion with berms might be the best plan, plus of course concentrating on planting salt -tolerant species as your framework. 

The tropical section of "Permaculture: a designers manual" has information about building and planting in hurricane-prone areas, but because it's tropical, not much of the planting advice might apply.

Ludi, thank you for that link.  Geoff Lawton is really inspiring. 

I think controlling the flow of flood might be as important in my case as in freshwater flooding.  I always thought of swales as something for people who have relief in their landscape -- I'm on flat tidal plain.  But of course it's not FLAT flat, and over the years I've come to know the high and low spots.  I'm going to revisit that information in the Permaculture Design manual. 

I can have sacrificial areas that are planted only in salt-hardy natives (which includes many useful plants).  I'm also focusing on incorporating improved varieties of natives throughout my design, and finding markets for those fruits and products rather than growing what everyone else already sells.

Ludi, thanks for the book links. I'll do a bit more research on the topic. What have you done over the years during times of flooding? Sandbagging the important areas and leaving everything else under floodwaters? Do you lose any trees, fences, and valuable topsoil each year in the flooded areas??

I would guess that especially in the first few years after moving in and planting trees that berming and adding lots of soil to the foot of trees would be quite the time-intensive activity. Just trying to figure out ways that a permaculture operation would be viable in such areas. Maybe all it is is embracing the floods, and mark the flood-prone areas on the property as pasture?

Anyone else cope with yearly floods, or frequent flash floods?

It is totally possible, and you don't have to be thye one interviewed by the news crew if you play it smart.

Is there a home already built there? If not, I have some ideas for you.

Ponds do little because they simply fill up, they become 'deep spots' which is actually dangerous for tractors/livestock scapering past for safety. Ponds dissapear during floods. The benefit of digging a pond is the amount of material that comes out of it- you can use this elswhere- to put animal housing/feed storage etc etc up high and dry on.

Find out the worst case water depth (200 year flood level?) and keep that in mind with everything that you do.

I've dealt with this a lot here, the 200 year level is 14' deep, so everything I do requires easy access to high ground, which I had to create, as it was a prefcetly flat field before moving here.

Were do you want to move? A flood can take whole houses with it sometimes earthworks. Your garden will be completely destroyed, and depending were you live there will be a lot of chemicals spilled over your land too.
There is a huge difference between flood and flash flood and the latter being far more dangerous.
I would not move in flood prone land.
You either make a hill and build the house on top of the hill on stumps. Or you build a house that can swim, but in Brisbane the famous swimming restaurant was destroyed because it was tied down to stay in place.

Well, I will probably have the chance to move to southern Manitoba this winter/next year. Been looking at houses with acreage just outside the Perimeter Highway in Winnipeg, and many of them are near/on the shore of the Red River. With a bit of luck, by the time I move there will be a house for sale well away from the flood zone - west of the city, but...

Anyhow, I'm doing my research, not jumping on what appears to be a deal, I'll definately take my time with this. What I am looking for is a relatively well-kept hobby farm or house with pasture fields. The selection area is small, since I will require to be within 45 minute's driving distance from downtown. Most of the flood waters within this area are fairly slow-moving since it is so flat (in '97, the river grew from 1/2 mile wide to almost 30). Silt goes everywhere in small amounts, waters last for one to two weeks then recede.

Foolish idea, or possible permacultural dream land?

AQ wrote:
Ludi, thanks for the book links. I'll do a bit more research on the topic. What have you done over the years during times of flooding? Sandbagging the important areas and leaving everything else under floodwaters? Do you lose any trees, fences, and valuable topsoil each year in the flooded areas??

I would guess that especially in the first few years after moving in and planting trees that berming and adding lots of soil to the foot of trees would be quite the time-intensive activity. Just trying to figure out ways that a permaculture operation would be viable in such areas. Maybe all it is is embracing the floods, and mark the flood-prone areas on the property as pasture?

Anyone else cope with yearly floods, or frequent flash floods?

Fortunately our house and outbuildings are uphill of the major flood area, so we haven't done anything when it floods except stand back!  The driveway has been washed out twice.  The first time we got a payment from FEMA to fix it because we were in an official natural disaster area, the second time my folks paid for the new driveway.  That time we had it redone with large rocks, which makes driving on it a pain but which we hope will mostly stay put next time it floods badly.  We're slowly trying to put in some earthworks as time and money become available.  We had a large berm and basin (aka "pond" or locally "tank") installed on one of the seasonal creeks the other year.  Eventually I hope to put basins throughout the home and outbuilding area to slow and infiltrate heavy rains.  Except for the road work and the large berm and basin all will probably be done by hand by me, a woman pushing 50. 

I live on the flood plain and am happy to have moved here.People warned me 15yrs ago when I bought but my research paid off as it has never actually flooded in my garden area.I chose a spot where the river has the most room to spread out.I didnt level the land but left the old channels for flood waters to travel through.Between the channels are high levies that I built the raised buildings.Around the dwellings I put berms around them facing the river.

Some flood-proofing strategies include building a house on stilts or on an area where soil has been bermed up by earth moving equipment, putting essentials utilities (electric box, furnace, etc) on the second story, building wall panels that will break off during a flood (along with structural posts sunk very deep to support and anchor the house). 

Really, I would rather have half an acre without flood that four acres which are flooding. You must bear in mind that sea levels are likely to raise in your lifetime.
A neighbour of us said that a bushfire is better than a flood as you simply start new, whereas in a flood you have to tidy up first.

Hi. I'm new and I live in a flood plain.

We bought the place about a year and a half ago. With the exception of last year, the stream had only breached it's banks maybe twice in the last 20 years. It is a small stream that is about ten feet wide from bank to bank and in the summer is down to a trickle. When it flooded last year, the water was about a foot deep at the base of the retaining wall (see photo). Fortunately, the flooding was all gone in about four hours. You wouldn't have even known that it had flooded. We bought the place because we like the idea of having a fresh water source nearby and for the seclusion.

I am not sure what to do in terms of gardening. I am currently reading Gaia's Garden and am hoping to apply this new knowledge to my garden design. I have a very steep slope on the far side of the stream that I was considering planting some apple trees on, but I am not sure if this is ideal. I could plant them up closer to the house.

The ground stays moist in the summer and after heavy rains some areas will be soggy for several days. In fact, last summer when everyone else's lawns burned up, I was mowing weekly. Because of this, I am not sure what to do. It seems that raised beds are the solution, but my property has such an odd shape that I am not sure how to lay it out so it doesn't look out of place.

Here are a couple of photos. One looking down the drive and the other islooking from just off the front porch, up the drive. We have an acre and the house sits on the back property line.

Half of Brisbane is built on a floodplain. It flooded 1974 and it flooded this year. A butcher took a photo of a bull shark in front of his shop 30 km inlands. Really I would never ever buy on a flood plain.

ediblecities wrote:
Half of Brisbane is built on a floodplain. It flooded 1974 and it flooded this year. A butcher took a photo of a bull shark in front of his shop 30 km inlands. Really I would never ever buy on a flood plain.

If I get a picture of a shark, then all of New Jersey is under water.

Tom, here's a video showing raised beds fit into odd shaped spaces, for growing in a wet climate:  http://www.youtube.com/watch?v=ugFd1JdFaE0

Ludi wrote:
Tom, here's a video showing raised beds fit into odd shaped spaces, for growing in a wet climate:  http://www.youtube.com/watch?v=ugFd1JdFaE0

Thanks for the vid.

No quick answers, but we are in the same boat.

Fell in love with a place right on the bank of a tidal river, in one of Ernie's favorite river valleys
We are just above the mapped tsunami zone, and the house is on a raised raprock platform, but rain flooding still overtops the road and saturates the back gardens of us and all our neighbors. Salt is an issue, usually about 4 feet down and mild brackish, but could get worse with sea level rise. We're on the Pacific coast, so king tides here can get impressive.

What they did in nearby valleys for homestead days was always assign strips of valley floodplain land with a chunk of the wooded hills alongside. Can graze cattle on the rich bottom lands in summer, then move them up on sheltered high ground in winter.They even made laws against selling off bottomlands at certain times of year after a lot of out-of-state buyers got duped. One couple built a house and then spent a lot of money raising it on higher and higher foundations - it's now at about 12ft of block under the original house.
Pre-European settlement, there were tribal villages right on the rich coastal inlets, often with a sheltering hill nearby...  There are shell middens being washed into the sea. I don't know as much about seasonal practices here as further north, but I gather the tribes had trade routes and fisheries that have continued into the present, and traditionally used a lot of the forest and swamp species for crafting and building materials. Smoked salmon, herring, and tuna are a big thing here.

Most of the world lives near waterways, one way and another, because it's such a rich set of edges. Access to transportation, fertile soils, easy trade inland and across the water, abundant wildlife and variety of diets.  Coastal areas end up with cultures of social competition and status (potlatch culture, political alliances, sometimes feuds and raiding) partly because it's so easy to feed a big population.  The inevitable disruptions of storm, tsunami, flood, rival economic movements may not be preventable, but the resources are there for the survivors to recover and rebuild without starving to death.  
Mild coastal and river-valley areas seem to end up with cultures of seize -the-next-opportunity, lots of creativity and coalitions of cultural authority.  Politics and charm are key skill for success. Harsh areas may end up a bit more authoritarian, work-hard-play-hard. By contrast inland areas, deserts, frozen lands, and marginal highlands often end up with deeper laws of sacred hospitality and "honor cultures," where disrespect is a big deal (because someone damaging your stuff or raiding your herds, or losing your status in a survival alliance, can make the difference between survival and starvation). That was the theory, anyway. Not necessarily relevant to your original questions, except that there are a LOT of people and communities in flood-prone areas, and a LOT of politics and technology around what are accepted private property rights and public interest rules and restrictions and infrastructure investments for land use, pollution, flood prevention, drainage alterations, etc.

At the county and municipal scale, there are often plans for flood mitigation including levies and zoning laws.  Some areas have specific rules about building in certain zones, or keeping crap out of waterways.

There are resources (on the FEMA website and via insurance websites) for how to build flood-ready homes. Stilts are one option.
Having a lower story that is block or concrete, and easily cleaned out after a flood, is another. They make rubbery floor "boards" that can be laid without glue, and can be rinsed and re-laid after a flood cleanout.
For places whose lower story is already too low, like cellars, sometimes these are vented and filled with gravel or stone, with screened gaps. The higher floor becomes the "ground" floor.
Often they are designed with screened gaps to let the flood waters in, but loose-filled with gravel or rock to minimize currents. Trying to pump out a submerged basement or lower floor results in a lot of lateral pressure on the sides and underneath.Basically the house tries to float, and it's not very good at it, so walls often shift and crack and get racked so doors and windows don't fit their frames well afterwards.

There are things like tide gates and coastal engineering.  They take a lot of permissions these days, at least in the western USA.

Be very careful about bringing in fill, because it can have unwanted consequences.  Most flood plains along rivers have defined areas for overspill.  Think about the areas next to the main river channel that always flood first. If you take up that volume with fill, the waters can be forced to rise higher and/or flow faster through the remaining river channels, causing worse erosion, or into new areas such as behind levies.  A spur of sandbags or raised beds could even cause worse erosion just downstream from the eddies. If your land "improvements" causes damage to someone else's property, you could be legally and financially responsible.

Think of the flooding as an asset to work with. All that muck is also nutrition.  Flooding valleys and estuaries are rich zones for aquatic and riparian life, and for seasonal grazing and farming. The Nile valley has lost some of its historic farm richness since they started flood control.
There's some great TED talks about shrimp farming and estuarine restoration in Portugal.
There are also some cool resources on tradition peasant rights in the fens of England and Scotland before the enclosures. Swamps can traditionally provide reeds, canes, and shoots for thatch and wattle-building, nuts and berries, crops like wild rice and cattails and other cereals, edible roots and shoots, grazing and forage for livestock and pigs, hunting grounds for migratory birds, game, and fishing.
A lot of those are legally restricted now, but wild bird hunters used to feed a lot of New York from the surrounding wetlands back in the day.  
Ducks are still legal to hunt in season, and raising domestic ducks can be fun and fits into permaculture models for bug/slug removal.  Many wet areas in the US have traditional wild foods like wapato, mushrooms, wild rice and other sedges, cattails, some rushes, arrowroot, skunk cabbage, berries like cranberry and blueberry, edible snails and molluscs, fish, frogs, even alligator is a fairly choice meat. Many of these are/were abundant staples or local delicacies for the pre-industrial larder.  The more well-known ones can be significant cash crops, especially those with choice flavors and super-food nutrition. We probably have not even discovered all the biodiversity and edible/medicinal species in our wetlands.  Draining those swamps to grow common crops, especially stuff that is easier and cheaper to grow broadacre on existing drained farmland, can be kind of a waste of potential.

When we personally chose to buy floodplain land, it was mostly because it was too beautiful to resist. This valley is locally known for more sunny days and better gardening conditions (rich silty soil), compared to the coastal fog bank, steep forested hills, or sandy recovered dune areas nearby. We accepted that it might wash away or get salt-killed some day, leaving us to attempt shrimp farming in the ruins, but we hope it doesn't anytime soon. So far we have more thriving young trees than there is really room for. The previous owners planted 20+ fruit trees about 7 years ago, and only one has died from possible salt. We prune regularly to reduce the likelihood of blight. And rub buds off to avoid the need for future pruning wounds.

We made up our minds that the beauty and richness are worth the inconveniences. Working on a backup plan for where to go when nature does its thing - there are options. As anywhere with natural disaster potential, we have friends in different elevations and risk zones where we can be each other's backup plan. A lot of the neighbors are ex-commercial fishermen and recreational boaters who work together when the water rises.  

If you are looking into land or improvements, talk to neighbors about historic floods.  Work with soil and water conservation groups and watershed authorities to understand what's legal and wise in your area.

Living in a floodplain (or on an island of raised ground near one) is being a custodian of the arterial walls of Nature's lifeblood.  Don't be atherosclerosis.

So is this no longer the Okanagan Valley or someplace more coastal in Washington?  Can relate with the various issues as we are in the Red River Valley outside of the Fargo, ND area.  Flat as a pancake .... "Come ski the sugarbeet piles as your winter destination!..." :-)   Rich valley clay soils for sure.....dealing with the high water table and the river a stone's throw from the kitchen window a challenge in flood season, a godsend for the wildlife and scenery the rest of the year.  Working with the county has been.....er.....'interesting'.  I think they finally figured out we are not trying to add more 'plaque' to the atherosclerosis that other interests have caused in the valley.