draining ditch..

[Mean Jean]

I had the same problem last year with a low spot.
I ended up installing a french drain as someone else suggested.
80 feet long and dug by hand.
Starts at 14 inches deep and ends at 25 inches deep.
Rule of thumb is drop roughly 1 inch every 10 feet.
Use 4 inch weeping tile.
Wrap tile in cloth and the another layer of cloth over the stone for backfill.
I wouldn't do by hand again. Rent a ditch witch for $80 a day.
I spend 3 nights just digging the thing.

 

[JB4310]

Actually, a water level is much more accurate than a transit or a rotary laser level.

I have a rotary laser because it is much faster and more convenient in many situations, but a water level is more accurate and never needs calibration.

The few projects where I have considered hiring a contractor I will ask them about water levels and if they claim that their expensive laser is more accurate, they do not get the job. They just do not have the engineering skills I want.

There can be no arguing with water, it's the basis of all spirit levels.

That's why I often recommend people use the water from what ever problem they are trying to correct, to aid them in the solution. Whenever I dig a drainage trench that has minimum percentage of pitch due to topographical limitations, I flood the trench to make sure it will work once the pipe is laid in.

The water level in the link does not look like a construction grade precision measuring instrument. For it to be accurate the containers on each end would need to be leveled independently or have precise markings around them so the water in them could be used to level them. Or do they just use the top rim?

This of course is splitting hairs, cause almost any type of "everyday" construction has a tolerance of +/- 1/4"

I agree with you in principle/ fact, the longer tube of water is going to be more accurate than the little bubble in a 1 inch tube. But that's pretty harsh sending the contractor home cause he's not familiar with a primitive water level I've never seen one used in construction, I have seen water filled hoses used to level ships in dry dock.

JB.

 

[CurlyDave]

...But that's pretty harsh sending the contractor home cause he's not familiar with a primitive water level I've never seen one used in construction, I have seen water filled hoses used to level ships in dry dock...

I just didn't hire any contractors who couldn't understand the primitive science behind a water level, but who thought their laser level was more accurate because it was expensive. Big difference between sending someone home and not hiring him in the first place. I want a contractor who understands that his high school physics course applies just a much in the real world as in his high school class. There are guys like this in the business.

I used to use water levels in construction frequently. Then laser levels came down in price, and I have a self-leveling one that is much faster. But, if it is really important, I still get out the old hose with two clear sections of tube on each end.

 

[JB4310]

I used to use water levels in construction frequently. Then laser levels came down in price, and I have a self-leveling one that is much faster. But, if it is really important, I still get out the old hose with two clear sections of tube on each end.



Well I said primitive, but how old can it be, how long has hose been around?

The concept of using water is very old, they probably used some type of open channel filled with water and took elevation measurements off that ???

How do self leveling lasers work? do they use mercury ?

I have a little torpedo laser, but you still have to level it using the bubble. Bought when they first came out several years ago, has come in handy for certain jobs. Cost around 200. back then, they probably give them away now.

JB.

 

[CurlyDave]

How do self leveling lasers work? do they use mercury ?

No mercury, they have an optical system suspended from a pendulum-type bearing.

I now have a Bosch, which can be calibrated. I used to have a Johnson Controls one that had no calibration, but it was stolen. Don't know if it didn't need calibration or if it just didn't have it.

They all come with some kind of a laser detector, which means they can be used outdoors, the detector will "beep" when the laser hits it even if you can't see the laser beam.

 

[JB4310]

Well this raises an Abstract question in my mind. What is level? a straight line parallel to the surface of the earth?

It can't go on forever like a traditional line we learned about in elementary school geometry.

I know with larger construction projects like bridges, the curvature of the earth has to be figured in.

How would that water level work over a long distance? would it be a straight line or curved with the earth? I suspect curved.

JB.

 

[CurlyDave]

You are right, it would be curved over very long distances.

 

[Egon]

How would that water level work over a long distance? would it be a straight line or curved with the earth? I suspect curved.

Best also add in atmospheric pressure as well as gravitation force to the question JB.

 

[JB4310]

I guess you could draw a straight line between the two ends of a miles long water level, but the only place it would be truly level would be at the center of the line. The further you went away from the center the less level it would be. Seems pretty basic, does that sound right?

JB

 

[bcp]

I've never yet had a project in which I had to account for the curvature of the earth.

Bruce