Drainage / Survey / Survey Methods / Gradient

Hello everyone,

can anyone tell me how, as a layman, I can best measure the slope of a drainage? We have four drainage inspection shafts at the house. Through these, I would like to calculate the position (the slope) of the drainage. What options do I have? I have already been to a survey once. There, a device was used that essentially consisted of long hoses filled with a liquid. My guess is that this system measured based on the pressure difference (possibly also a kind of level). Does anyone know what this could have been? Possibly such a device can also be rented? Then there is still the option to do this with the help of a [Nivelliergerät]. Here I am a bit afraid of making errors in the measurement. I need a reliable method. Any ideas?
Thank you very much in advance for your help.

Schorsch

My suspicion is that this system measured based on the pressure difference (possibly also a kind of spirit level).

Correct! It's called a water level. There are very simple versions where renting it is not worthwhile, up to precision instruments that are more complicated to use than leveling devices. How accurate would you like it to be? If it's not urgent, ask some surveying office if they would like to assign a trainee a nice practice task and how much the costs would be. You would also be available as a measuring assistant.

Measurement errors

... you can also handle with the water level. And you still have to go down to the bottom of the shaft. How deep are the shafts approximately?

Hello Escroda,

thank you for the quick response. Are these essentially the two options I have for the surveying (leveling instrument and hose level)? I would like it to be precise. Accurate to one centimeter. Is that precise in the sense of your question?
Maybe a brief background. There is a legal dispute between me and the developer regarding the drainage concept of the house as well as its sealing. We have already had two experts on site who measured the drainage. It seems that one of them (at best) made a measurement error. The statements I have regarding the drainage are therefore: everything compliant VS incorrect course of the drainage. Now we are at the point where an expert will be appointed by the court. As you can imagine, a lot of money is involved here and my security that the entire drainage system actually works. So I want to be CERTAIN that what is measured next regarding the drainage is also correct.
You can’t imagine what a fuss I’ve already had regarding experts….

Many thanks for the support

Best regards

Forgot to specify. The shafts are approximately 3 - 4m deep, I would estimate.

Hello Escroda,

thanks for the quick response. Are these basically the two options I have for the surveying (leveling instrument and hose level)? I would like it to be exact. Accurate to one centimeter. Is that "exact" in the sense of your question?
Maybe a brief background. There is a legal dispute between me and the developer regarding the drainage concept of the house as well as its sealing. We already had two experts on site who surveyed the drainage. One of them seems to have (at best) made a measurement error. The statements I have regarding the drainage are therefore: everything compliant VS incorrect course of the drainage. Now we are at the point where the court will appoint an expert. As you can imagine, this is about a lot of money and my assurance that the entire drainage system actually works. So I want to be CERTAIN that whatever is measured next regarding the drainage is also correct.
You can’t imagine the hassle I’ve already had regarding experts…

Many thanks for the support

Regards

If you have a leveling instrument at hand... then everything fits and will be very precise! ...if you also happen to have an existing NN height, you can directly convert it to the correct heights.

However, the expert appointed by the court will still become active.

Good luck

You gain security when a professional you hire measures simultaneously with the expert. You are a layperson, as you wrote, and will probably get 3 results from 3 measurements and unsettle yourself.

It would be interesting to learn more about the specific problem:
What slope is present, what should it be in your opinion?
What exactly is the damage scenario that you fear?