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THE SIMPLE WATER LEVEL
The least expensive method of determining the gradient of virtually
anything is with the use of water. Water seeks a level automatically.
One can make a water level by attaching garden hose fittings to
two (2) foot lengths of clear plastic tubing, a male and female
fitting on opposite ends. Then each clear hose can be attached to
a common garden hose. The length of the garden hose does not matter,
nor does the terrain in between the two ends of the hose, as long
as it is not higher in the middle than the ends of the hose.
Erect a post at each side (or end) of the site to be measured for
elevation, and tape or tie with string the clear plastic tubing
to each post. Make sure all connections are tight and do not leak.
Then fill the hose full of water, letting it settle and air bubbles
escape, until the water maintains a level visible in the clear plastic
tubing. It may be necessary to raise the lower end of the hose if
water pours out, until it too maintains a level that is both visible
and stable. If the water level fluctuates, then there is an air
leak in one of the hose connections: tighten the connections and
try it again.
Once the water level is established, mark that
spot on the post. Those marks indicate a precise level between the
posts. You will know the height of the foundation on the lowest
corner: mark that spot on the post with a carpenter's square.
Measure between the two marked lines on that post, write down the
measurement, and then measure down that amount on the other post
from the water mark: that lower mark line is the top of the
foundation in that location. All four corners of a building
can be leveled in the same way, keeping one end of the water level
tied to one post.
A tight string line can be established between
the posts, and if more posts are needed in the middle for a
construction project, the string line will indicate the level for
each one. Huge barns used to be built flat and level using this
method. But remember that while using a water level can indicate a
precise height, it does not indicate "square"!!! You still
must measure the diagonals between corners to establish a perfect
square or rectangle.
Even canal's were surveyed in the old days using
water levels, so a water course could be determined for running a
water wheel grain or saw mill.
This system will also work to determine the
gradient of a slope. Posts are driven into the ground and the water
level used between them Then measure the distance from the mark to
the ground on each post is measured: the difference in those
measurements is the gradient of the slope, but not the percentage of
gradient. For that percentage, you will need to measure the distance
between the posts and do some simple math: a 10 foot drop in 100
feet is a 10% gradient, for example.
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