Water level (maximum) – inky tape method
Parameter to be measured:
Maximum water level
Method:
Equipment:
PVC tube 25 mm diameter PVC tube 20 mm diameter Old 30 m fibre glass tape measure Washable ink Cap – I used old lab sample tubes.
Construction Sections of 30 m tape measure are coated in washable ink on both sides, allowed to dry then stretched along the inside of a thin PVC tube (20 mm) and attached at each end with electricians tape. These tubes have a single small hole at the top of the tube to allow air circulation and are left open at the bottom to allow water to enter; they are placed inside the larger diameter (25 mm) PVC wells then capped with an old sample tube taped on but leaving a hole to allow air to circulate in the tubes.
As the water level rises in the tubes ink is washed off to leave clean tape up to the height of the maximum water table. To read the maximum water table height over a given period you simply read the depth to which the ink has been washed off. To reset you re-coat the washed section of tape with washable ink.