Moving Dirt

[JimD]

We are finally about ready to close on the new lake house which I wrote about before. It has a small 12x12 shed and a 2 car garage. So I will be giving up shop space at least initially. We're talking about adding another garage stall both for my tools and for the larger FROG (finished room over the garage) for a grandkids area (don't have them yet but have to plan ahead).

The ugly surprise we got 3 weeks ago is that the house is "in the flood plane". What that means in this case is that one corner of the crawl space would get 1 foot of water in it in the theoretical 100 year flood. The first floor is more than 3 feet above this level. So only masonary would be contacted by water. But the mandatory (if you want a loan) flood insurance is $2400/year. I don't think it would do $2400 of damage even if this happened and they want that every year.

But the best way out is to use fill to raise the elevation of this part of the yard and corner of the crawl space and get FEMA to change the map and take the house out of the flood plane. They have a specific form and procedure for this.

Which gets me to my question. I will need to move a pretty good truckoad of topsoil, I estimate. Something like 20 tons. It can't be driven to the back yard where it is needed, there is no room. Taking out part of the fence might get a bobcat through. Our I could use a cart behind a mower and/or wheelbarrows. Or I could just hire it done. Or maybe you have other ideas. What would you do? I will probably get a quote before deciding. I think materials are around $1000. If I could get it done for 2 to 3 times this, I'm thinking it would be something to just pay for. I have plenty of other projects on this house.

[capncarl]

You ask, " What would you do?"
Not what you want to hear, or on the same topic as moving dirt, but..... RUN, Run fast and don't look back.

Flood plain means floods. Water, sometimes lots of water. I lived in a flood plain for 29 years. When we bought the house the property had never flooded and no records could be found that the creek had gotten out of its banks. Every year after we moved in it flooded the yard and garage. The last 2 years it got into the house and caused 4 ft of damages. IMO Just the water in the yard would be reason to not buy. Too much troubles with septic tank, well, stuff floating off, stuff floating in, and all the critters that crawl up.

Getting FEMA to change the map will not help, possibly could hurt your situation. My dealings with FEMA prompts me to believe that it would be impossible to get them to change anything. They are government you know.

My wife talked to my old neighbors in the flood zone recently and learned that their flood insurance price is rising drastically, possibly to as much as 10k per year.

Run Jim run.

capncarl

[All Thumbs]

I can relate the same story, I have a friend back in the Midwest that was trading-up houses pretty rapidly. He'd buy one, fix it up, sell it, and use the proceeds to buy the next. It all stopped when the one he purchased was in a floodplain. He didn't notice the disclosure on the report (it was checked, he wasn't thorough) before signing, so he was committed to buying.

He tried to put a positive spin on things. Neighbors said nothing ever floods. Previous owners told him "don't worry about it, it is a designation, but it never happens."

So he proceeded to fix up the basement. New drywall, carpeting, the works. Three months later heavy rains came, basement flooded.

So he fixed it, and brought in fill to change the landscaping. Months later, heavy rains came and destroyed the basement again.

So if you can still walk away, I'd do so.

[woodturner]

You ask, " What would you do?"
Not what you want to hear, or on the same topic as moving dirt, but..... RUN, Run fast and don't look back.

+1 on that.

Some years ago, I lived in the desert. We had two "hundred year floods" in the three years I lived there. Major damage each time - washed out roads, bridges, etc.

Don't do it.

[Carpenter96]

I live in a house that is on one of the highest hills in our area. If my place floods the rest of our city will be 100 feet under water. I have lived on flood plains in the past and not had a problem. But when it came time to purchase my own home I knew that high and dry was the way to go. It seems great to live right on the water until it comes inside. Then no one is on your side. Run if you can, and enjoy if you can't.

Bob

[JimD]

I could still back out but I won't. This is a lake, not a stream, and has massive flood gates. The lake is 47 miles long and 14 miles wide. The utility that operates the hydro unit on the lake starts action at 359 feet - as a condition of their federal license for the facility. Full pool is 360 feet and rarely reached. The 100 year flood elevation is 362.5 feet. The level of my first floor is 365.6 feet. We got several inches of rain over the area this week. It didn't even push it to 359 feet.

So it is credible my back yard could flood sometime in my lifetime but not very likely. It would be me plus several thousand other people who live around the lake impacted. Many of the homes are well over $1M. Many docks would be damaged and boats. But I just don't see a credible possibility of a rise in water more than twice the 100 year flood. The theoretical 100 year flood is 2.5 feet over full pool. I have more than 3 feet of clearance before it come in my house at that point. That won't happen. With some work, I can keep water out until something greater than the 100 year flood occurs. I think that is an acceptable risk considering the size of the lake and active management of the level. All my mechanical equipment is also above the 100 year flood level.

I wouldn't buy a home along a creek or river subject to flooding either. But that isn't what we're doing. I'm willing to accept that I might have to briefly go to my son's house for a few days if the septic becomes flooded. I might also have to remove some debris from the yard and even fill in some holes or other damage. But nobody is saying there is a credible risk of water coming into a finished space. The garage is also well above the 100 year flood level. It is just one corner of the crawl space that is below. The very limited area that is too low is why it seems feasible to me to solve it with fill.

Jim

[woodturner]

But I just don't see a credible possibility of a rise in water more than twice the 100 year flood. The theoretical 100 year flood is 2.5 feet over full pool. I have more than 3 feet of clearance before it come in my house at that point. That won't happen.

Kind of what I thought when we lived in the desert.........

30 feet of water in the desert that overflowed from a "creek" is a sight to behold, let me tell you.

It's your decision, we just don't want you to be surprised when your "won't happen" occurs yearly for the next decade.

Just to be clear, the "100 year flood" mark is the level to which water is expected to rise, on average, once per 100 years. The problem is that most of the maps were made a long time ago, and building of houses and infrastructure has changed the conditions, often dramatically. In addition, it's simple statistics - there is nothing that prevents a 100 year flood annually for 10 years, then no more for 1000 years.

Really, there are just so many "red flags" in what you are saying that it's really, really scary. If your mind is made up, why ask for other opinions? You could be right - but what if you are not?

Lots of people build and buy houses in environmentally risky areas. Think of all the mudslides in California - people built million dollar homes in areas where mudslides were expected. It was no surprise when their mansions slid down the mountain. Same thing with many of the wildfires.

As a practical matter, to get a better answer to the question you actually asked, you may be better off to talk to DIYers and contractors in your area, to folks that might have done it before and have already "drunk the kool aid".

[Mr__Bill]

Living by a lake is nice, don't believe it can't flood but the risk may well be worth it.

As to the original question, I have seen conveyer belts used to move dirt into inaccessible places. There may be someone in the area that is set up that way. However it gets moved I would have someone do it and not do it myself. That is bull work and with a new house there it too much to do to get bogged down in that. I would also consult with someone as to just what kind of dirt is best to use. Top soil can be very porous and let the water through and you still get a flooded crawlspace.

Is a flood plane considered 'inland wetlands'? will you need approval from some other agency?

Bill
on the left coast, where don't have to worry about the big lake flooding, just tsunamis

[All Thumbs]

The very limited area that is too low is why it seems feasible to me to solve it with fill.

Jim

One thing I forgot to ask in my original post: How will bringing in fill get that corner of your house out of the flood plain? Unless you can increase the elevation of your home, that corner will still remain in the FP, won't it? You can't just build a berm between the house and the lake, the feds won't go for that.

[JimD]

I don't mind the advice about the flood plane but what I really asked about is moving dirt.

I should probably post the sketch so you would understand better but the situation is that one corner of one room is over a crawl space where the dirt is at 361.5 feet. The 100 year flood is 362.5 feet. The ground rises rapidly from that point so that the other side of the same room is above 362.5. So it is just the corner of a 14x16 foot room (the dining room). The plan is to fill in that corner of the crawl space and also put fill outside to lift the elevation to about 363. That's about 18 inches of fill at the low spot tapering off to the ground level less than 20 feet away that is already at 363. FEMA says that with a elevation certificate showing implementation of this plan they will reclassify the house as out of the flood plane. I already asked FEMA. They have a form just for changing the classification based upon fill. I know people who have done this.

I will also point out again that causing a flood at a huge lake with active flood control in service is not the same risk as a creek flooding. It take a LOT more water. I'm not saying it can't happen, just that the volume required especially considering the flood gates would be open make it much less probable and also tend to limit the magniture it can go above.

[JimD]

FEMA also requoted the insurance to a much lower number today. So maybe they are getting rational about the risk. I further learned about flood vents. They are relatively inexpensive and are not to prevent flooding. Their purpose is to let flood water in and back out so the wall doesn't collapse. One insurance agent thinks another insurance agent is crediting the existing always open vents as flood vents (and she is not). I don't care why they want dramatically less, I just like the change.

Reducing our annual cost for insurance by 80% will change my timetable for adding the fill. It also makes it more likely I will do it myself. It would take 5-10 years to justify the project if I hire a contractor. But I still think it makes sense. If we ever move, it would raise the house value to remove the stigma.

[chopnhack]

To Jim's first question of dirt: You will have to resod a section, but have the dirt dumped into one location, hire or rent a dozer and move the dirt to your desired location. The action of circling the area with the dozer should be adequate to compact it. Do it in several even lifts, check your work with laser level on tripod or periodically setup masons string lines and story pole it. Keep in mind, dirt does wash out.... you may want to consider getting an engineer to evaluate your proposal and perhaps design the proper foundation, whether that be piers that are pounded in, poured concrete columns, etc. That way even if you do suffer some washout, with deep piers you will remain structurally sound. Sound like overkill? Maybe, I didn't know the flood plain of my area until I started getting these bills from FEMA - F'in Every bit of Money my A.s.s ever made Apparently my bill is set to double, but I haven't seen it yet. Nothing I can do short of demolishing my property and raising it out of the flood zone.

By the way, bulldozers don't have to be the huge one's your probably imagining, you can rent a small excavator with blade, I have on occasion and they are priceless. Small footprint allows them to get into small areas. The last one I rented was about 4' wide at the blade, less at the track. HTH

[JimD]

Thanks Chopnhack. We will look into renting a bobcat. My wife actually wants to run it. The hard part of the job will be getting the fill into the crawl space. I don't need a lot of dirt in there but I have to raise the one corner at least a foot and I plan to raise it 18 inches - in case it settles some and to provide a little margin. I need to add fill to about half a 14x16 foot room.

The attached sketch should help you understand. The 362.5 line (100 year flood elevation) is shown and the elevation at various places on the building is also shown. To make sure I get the dirt to the right elevation we plan to just index off of the brick foundation. I'll check it but I think the rows are fairly level - at least within 6 inches. To ensure I have drainage away from and around the building I will use a 6 foot level plus the reference of the house foundation.

I'm leaning towards a cart we already own behind the John Deere yard tractor. It won't tear up the yard as much as other options and avoids the wheel barrow routine. I might go to a bobcat when I get the crawl space done. For that portion, getting it to the access door will only be the first phase of the effort. It will have to go under and then be leveled. I might use fill sand mainly because it will level better but also because it won't support weeds and is nicer to crawl on later. Outside the wife has dictated topsoil which isn't terribly expensive here.

If you can't get your house reclassified, adding flood vents looks like a smart thing to do. In my case, it seems to be worth a 75-80% reduction in flood insurance. Vents cost as little as $60 each.

[All Thumbs]

It (adding fill) seems like such an easy and obvious solution, I sort of wonder why it wasn't done previously. I assume you won't be reducing the distance between the ground and the bottom of your joists to less than 24" at any point (the local building inspector may have something to say about that), and that any foundation components that may be below grade as a result can handle the moisture.

For the crawl space I might be inclined to check with a local ready-mix type outfit to see if they have any fill they could pump. The rest of the property you could use your bobcat and cheap fill. But I sure wouldn't want to try shoveling that much fill into a crawl space.

[JimD]

The flood map changed in 2000 and the house was built in 1965. The dining room where the issue was probably added later but not recently. The windows are double glazed but the spacing looks to be about 1/4 inch apart - not nearly the inch that is typical recently. So it significantly pre-dates the last changes in the flood maps. There is only one former owner - the original owner - so nobody has had to deal with this until now.

The finished floor is at 365.65. The floor joists are 2x10s so the bottom of the floor joists is about .8 feet below the finished floor or about 364.8 feet. I am thinking of fill to 363. So I would maintain nearly 2 feet of clearance to the bottom of the joists. It will be more difficult to move around but most of the crawl space is higher than this already. I hadn't thought of it but that would also be another easy way to check progress in the crawl space. The fill should come up to about 1' 10" below the floor joists. That will put it very near 363 feet.