Tide Level Device

In order to measure the relative water level (relative to known sidewalk heights) within the canals of Venice, a measuring stick has been constructed. The stick is placed vertically in the water and photographed; the photos are later analyzed to determine the water level in the canal at the time the photo was taken. This device was placed in key locations and several canal measurements were taken easily and in a small amount of time. Water level data collected with the device was compared to the actual tide levels recorded at the Misericordia tide gauge - through this comparison, we were able to determine that the measuring stick method collects very accurate measurements.

Photographs of the measuring stick in the water are taken (left) and each photo (right) is analyzed to determine the water level in the canal at the time of the photo. The measuring stick is placed in a location with a known sidewalk height relative to the 1897 Punta della Salute zero point (obtained from Insula) and the number of centimeter increments is counted from the sidewalk edge to the surface of the water to calculate the water level

In the future, the sticks could be further developed to be stationary devices in several canals and could be incorporated into a citizen science effort. Essentially, people could take pictures of the sticks and upload them through an app. Such an app could determine the water level and record the water level, the time the picture was taken, and its location.

Design:

The measuring stick that was constructed in Venice is made from a length of white fiberglass that is 2 meters long, 3 centimeters wide and approximately 2 millimeters thick. The strip's material is flexible but resistant to salt water. Centimeter-wide black stripes were spray-painted at 1-cm intervals, and every 4 centimeters the pattern alternates between black-and-white stripes and black-and-color stripes.

This color pattern and increment design was intended to allow water level readings to have centimeter accuracy. In the case that the photo from which the water level is being taken is difficult to read (due to poor photo quality or far distance from the stick), the alternating colors will allow an approximation of within 4 centimeters.