Regarding the link to the Well Watch 660, I now have several installed on our water company wells.
There are a couple of problems with it for a river level application. It will not work over an open channel (needs a stilling well), and it has a minimum distance of 10'. So, you would need a pipe > 10' for a stilling well extending into the river.
What max level difference in the water level are you looking at? If you can implement a stilling well, you might be able to use Milone Level Sensing Tape as I mentioned in http://www.wxforum.net/index.php?topic=25127. Check out that thread, Adafruit, and the Milone site for more details
Good Morning SLO,
The maximum change in level to be monitored would be 18 feet, but generally would be -2ft to +10ft from the reference level. Anything greater than +16ft would probably wipe out all the equipment and my cabin!
I do understand that I will need to take into account the open water. I am contemplating how to go about this with ideas such as a stilling well as you mention. Wave action from wind and boat wakes will influence the operation of the sensor as well as debris floating on the surface.
I have two main goals in this project. The primary goal is to monitor the river level during flooding. The secondary goal is to monitor the actual water temperature to gauge fish activity during fishing season.
When this river floods, a great deal of debris is discharged from the various tributary creeks and farmland. Corn stalks, leaves, twigs, branches, stumps, whole trees and other vegetation accompany most floods. Not to mention refuse garbage, unfortunately. In late winter or early spring there would be crushing ice and slush.
Therefore, I obviously must account for all these conditions so that the sensor may read accurately, consistently and must also be protected. This may prove to be more challenging than designing the sensor itself and making it communicate with my weather station equipment.
One idea I have is to set a vertical culvert along the river bank in a protective cove and mount the sensor above it in a shelter house or box. I have several corrugated, black ABS plastic culverts which are ~14" diameter and 20 feet in length. There are many 1/2" holes drilled into the sidewalls throughout the length as they were originally used for drying grain, so they are already perforated to allow water to enter and exit freely. These tubes may make a fairly decent stilling well, if I protect them from the major icebergs and large trees.
I could also put a "tube inside a tube" using one of these culverts on the outside and a 6" PVC pipe inside to baffle and filter the water further and protect the inner tube even more.
The Milone sensing tape may be an option here, but I don't know if they offer them in the length that I would require (at a price I would be willing to pay). That may require some engineering to utilize several strips to make the full length.
If I could count on the conductivity of the water remaining fairly consistent, I could make my own sensor using two SS rods inserted inside a perforated PVC tube. The change in conductivity (or resistance) as the water level rises or falls could be monitored and the signal conditioned to emulate the output of the temperature probe for my weather station. This would require additional circuitry to condition the signal, but could be done fairly inexpensively. The major problem here is the variation in the conductivity of the river water when it floods. If the percent of change of the conductivity is much greater than the percent of change in the water level, then the output signal would be misleading as it would be changing more rapidly than the actual rise in water level.
The conductivity, due to contaminants and salts, could not be calculated for because this may change greatly depending upon where the rain fell and where the water runoff came from. If the watershed has high iron, mineral or salt content in the soil versus the runoff coming from melting snow over frozen ground, the conductivity could be extremely variable. This would require a secondary sensor to monitor the conductivity of the water and additional circuitry to compensate for its change. That is more work in engineering and not what I really want to engage in for this "simple" DIY project.
I need to read the whole discussion regarding the Well Watch 660.
Thanks SLO,
RADAR
