Scientists work to keep Oregon’s Crater Lake clear for years to come – OPB

(Juliet GRABLE, Jefferson Public Radio; September 17, 2022)

https://www.opb.org/article/2022/09/17/crater-lake-oregon-clear-water-quality/

Also…

A Printable Device for Measuring Clarity and Color in Lake and Nearshore Waters (BREWIN et al., 2019)

https://www.researchgate.net/publication/331294915_A_Printable_Device_for_Measuring_Clarity_and_Colour_in_Lake_and_Nearshore_Waters/download