Cistern

[Darren]

I'm planning to work on a cistern this summer. A couple of years ago my neighbor leveled out a place on the hillside. After that I dug out a pit 50' long 15' wide and 13' deep.

The location is not easy to access. Getting the excavated material off the hill was the worst part of the job. This summer the plan is to clean out the excavation and begin the cistern itself.

I'll have an engineer design the walls to avoid problems. the plan is to clean out the excavation. Go deeper for more capacity if I can. Pour a mud slab to work on to layout the slab rebar. Pour the base slab. Build the walls out of 12" block using durawall in each horizontal joint and rebar in the cells as required.

After three levels are up and sufficient time has passed, the cells will be filled with concrete using pea gravel as aggregate. Then the next three levels will be laid, etc. This will continue all the way up.

When the walls are complete, Q deck and perimeter formwork will be used to support the pour for the top slab. Now the problems.

Since the site is inaccessible to a concrete truck, all of the concrete will be mixed on site. I've got that figured out.

Getting the concrete into the hole for the mud slab and the base slab is my major problem. I'm looking for ideas.

Two that I've considered are using an excavator with a concrete bucket or trying to find a small concrete pump (which doesn't exist in this area). That's were I need some ideas. I'd like to find the cheapest way of moving that concrete.

 

[Anonymous Poster]

My first suggestion would be to do a cost comparison against multiple poly tanks, such as large septic tanks.
A block wall on top of a slab is going to leak, I have one, and I guarnateee it will leak.
A monloythic pour for the floor and walls would be better, and justify the cost of bringing a pumper into the job. Make sure to use a vibrator on all concrete to minimize airpockets in the final floor & walls.
If frost is a possibility, stay away from concrete if at all possible.

 

[MossRoad]

I agree, one large or several smaller plastic tanks seems like it would be lots easier than concrete or block.

 

[Egon]

I'd have a tendency to go for the concret bucket.

On the wild side would a grain auger work?

There are very durable plastic sheets that can be welded together which could also be considered for a liner. I do not know where this material is available but an Oilfield Supplier would probably know as it's used to line pits containing contaminating fluids.

Egon

 

[herbenus]

A well sounds easier to me. My only experience is setting up a barrel under the rain gutter down spout...

 

[Darren]

There's no way to get a pumper onto the property much less anywhere near the site. I can only mix a yard at a time so large yardage pours aren't feasible. The site is located on the side of the ridge behind the house high enough that I have a 100' difference in elevation to get the water pressure I need.

If you look at the pit size it's big enough for a 50,000 gal. cistern. The problem is that the wells don't produce much during the summers. I plan on setting up the well pumps so they're on timers. During the winter and spring and maybe during the night at other times of the year, water will be pumped up to the cistern and stored.

I figure that's the only way I'll be able to get enough water to keep livestock. I've even seen so called monolithic concrete basements leak because contactors wouldn't spend a few bucks on a waterstop. If it leaks, the construction was incorrect.

As for plastic tanks which could be hauled up the hill, the small ones, even a bunch of them, wouldn't provide the capacity in the space available. One large enough to hold the water would be too big to get on the property much less up the hill. A septic tank would be impossible to get up there too. There's no room for a large truck to get up there and turn around even if you winched it up and no one in their right mind is going to come off that hill backwards.

I've been looking at augers for moving lime. What I found out is that grain augers are too lightly built to handle lime much less concrete. A conveyor system would work but those are like hen's teeth around here.

 

[Von]

How about large fuel tanks like the ones gas stations use? You could have them placed by chopper, Its cheaper than you think. Might be cheaper than all that concrete, and less work as well. Plus much less chance of it leaking.

 

[Egon]

Darren:

Again on the wild side:
As the location sounds steep and cramped could a small tracked loader with a 1-1/2 yd. bucket be used to haul the concrete up and pour into the forms. Segregation may be a problem. This method may also enable you to use ready mix. Thoughts to mix with the thoughts of others.

Didn't think the grain auger would be feasable but worth a mention.

Egon

 

[jsnitz]

How about a swimming pool liner?

 

[MossRoad]

Just for fun <A target="_blank" HREF=http://www.watertanks.com/>http://www.watertanks.com/</A> has lots of tanks. You might want to look around. /w3tcompact/icons/smile.gif