Flood preparation

[GarthH]

Hi all. I have just come from a meeting that our local government is thinking that we may have some flooding. We had near record rain fall last fall, and have had above average snow during the winter. The last ingrediant is how fast the snow melts and whether we get some spring rain.

To make matters a little more challanging we are just moving into our acreage which runs beside one the largest river system in our area. The river is dammed so it is not expected that they will have trouble from the river itself even though our house is only 40 feet above the river level.

I need to find some old guys around the area but it seems like our biggest risk is running through our yard and maybe the house on the way down to the river. The land behind us is about 50 feet above us.

At the seminar the guys were talking about portable damns or dykes. Has anyone heard of them or know much about them? I ran into a few on the web but they look very expensive - maybe nothing like the possible damage.

My other concern is the septic tank. It is about 12 feet below ground level with the liquids running off into a septic field. I am guessing there is some type of one-way valve in the tank. Do you think it can take the weight of 12 feet of water? Maybe there is a water proof top I could find for the tank cover?

The ground is still frozen so it would be tough to get a loader into to move dirt around. I was thinking we could order some sand / gravel but I think it would just wash away.

Any advise will help. This is a first for us so we don't really know how to handle the situation.

Thanks

Garth

 

[dooleysm]

I have no experience with flooding, but I know there's no one way valve on our septic tank, just gravity.

 

[schmism]

if the water table rises above the level of the septic tank, it WILL fill with water.

Even if it doesnt back fill from the drain feild, the drain feild wont drain, so any water you put down the drain simply builds up and again WILL fill up.

the local county courhouse will have USGS maps which specify 50-100-500 year flood levels.

you can get those elivations and correlate them to what may or may not flood depending on how bad a flood is. (the longer the year the more sever the flood)

as for keeping water out a location....

I think the best solution is to plan to have it there and deal with it...

before i worry about sewer, id worry about my water supply.

 

[RonMar]

How big is the "pipe" you are talking about. Flooding or flood level is a factor of the supplied water versus the outflow channel size.
You need a topographic map of your area so you can find the choke point downstream that could possibly back up the water high enough to reach your home. Someone should have already done this figuring if any form of flood planning has been done in your area. I personally would want to know the lay of the land so I could estimate how fast the water might rise and how much time I had to make preparations to leave. I am not sure how insurance works in your country, but do you qualify for flood insurance? That usually indicates that you are in a likley flood plane.


The septic will flood one way or another if the water gets high enough, don't worry about it. it will re-establish the proper level once the water recedes. You can use a bucket/portable toilet for your waste and dump it in the river as it will already be contaminated from other peoples septics that have flooded As mentioned, worry about the fresh water supply. Seems silly in a flood, but that is usually one of the things listed in short supply during a flood. A good deep cased well should be OK, Is the top of the well casing sealed? Most are vented in one way or another and usually have penetrations for the electrical power for an in ground pump. If the well head goes under water, the well will most likley be contaminated so you may need alternate water for a long time. You may or may not have power to pump from it anyway.

Loose dirt and sand won't stand much of a chance against running water. Sand bags do better but there is an art to stacking properly and filling/positioning takes an army of people. Regardless of these two methods leak. Do you have pumps? Only thing that has a chance in that situation is properly engineered concrete. But, what are you going to do, put a 10'-15' high concrete wall around your house? You would probably be better served raising the house on piles.

Sorry to sound gloomy, but the water usually wins. Before you have to evac, move all the easy valuables as high in the house as possible, furniture too if you can. They may survive if the house dosn't go completely underwater. Pre-stage food and safe/sealed drinking water in a way that you can take it with you quickly if/when you have to leave.

Good Luck and keep your powder dry, you may need that too

 

[ByronBob]

Focus on your home and make sure you have pumps and power to battle water in that manner. The volume of water your talking about you can't win against.

Flooding only becomes a nightmare when it's inside your home. Water recedes within a 3-4 day period anyway.

Your thinking about it ahead of time. I'm sure you'll do ok. The septic will be fine.

 

[schmism]

Water recedes within a 3-4 day period anyway.

unless you liveing in new orleans......

depends on your river... ive lived on/near the mississippi almost all my life. when she goes out... she stays out for a while!

 

[SPIKER]

Like others said water will get in where it wants to go. Pumps, (gas generators and drinking water are more important.) BE prepared to take you're butt & run! don't wait until last min either. get stuff up on higher levels, maybe take un-replaceable items to a secure safe place. (pictures birth certs titles ect.)

move valuable furniture & tvs ect to high rooms too.

markm

 

[GarthH]

Thanks for your help. We are only a few minutes from the city so we always stay with relatives during the mess.

Drinking water is not a real problem - we have a well that is in good shape and shouldn't be affected. Later in the year we have a water pipeline coming in that will have city water.

My biggest concern is the house. I did find some old timers in the area who all indicated that the last owner had never had major troubles. Of course I don't think he had a record runoff.

The weather is breaking today it got to low 40's and is expected to be in the mid 50's over the weekend. It would be nice if the temperature went back down after the weekend.

I haven't invested in a gas powered pump I had several large electrical pumps.

This property we are just taking possession on May 1st but we wanted to move the date up as our house in the city is sold as May 1st as well. I have been looking into insurance but once they figure out the potential flood problem I suspect they might exempt floods.

Garth

 

[Ray2210]

Garth I'm just East of town towards Clavet. The melt so far has been gentle in our yard. It's actually been slower and easier to deal with than the last two springs. We have made a few small changes that have made dramatic differences in how the water moves about the property. With that said we were out walking the dogs last night to find a creek running down the ditch and also to find that the grid road had been breached futher up and was starting to wash out. By this morning the first wash out was pretty minor but a larger (yet still navigable) one had appeared much closer to our property. Though it looks like alot of snow has melted there is still alot of snow left to melt and with the temps forcast for 8 degrees c and sunny with + temps and rain for tomorow it could get real interesting. I brought my rubber boots with me to work as I'm not counting on being able to drive back in tonite. Neighbors who have lived in the area for 25 + years have never seen anything like it. Best of luck to you

 

[teg]

It's expensive but a great peace-of-mind... flood insurance $700/yr, ouch! Pretty much you can try and fight the water (sand bags and such) but you'll never know how high it will get. The septic would be best if it fills with water (vs. trying to float!). I would be much more worried about the well water getting contaminated. Only other option, is build higher (if it gets the house) or move it later (if it doesn't get the house).