How do you measure sludge depth in a lagoon?

You can measure the depth of water and sludge in a lagoon using a Sludge Judge®.  A sludge judge will allow you to measure the depth of water down to the surface of the sludge and then push through it to actually sample the sludge as well.  You can also use a rod or pvc pipe with markings to find the depth from the water to the top of the sludge.  The depth of sludge is the difference in the top of the sludge and the firm resistance of the bottom (usually clay, liner, or concrete).  A GPS or transect system can help you calculate the quantity of sludge in a lagoon.