Using a Secchi Disk or Transparency Tube
https://archive.epa.gov/water/archive/web/html/155.html

Environmental Protection Agency


This EPA website provides instructions for using Secchi disks and transparency tubes to measure water clarity. The page also features a short description of each device.

This resource is referenced here:
Subject: Biology:Ecology:Habitats:Water Column, Biology, Geoscience:Geology:Sedimentary Geology:Sediment Transport and Deposition, Geoscience:Hydrology:Surface Water:Water Quality/Chemistry
Resource Type: Activities:Lab Activity, Field Activity, Scientific Resources:Overview/Reference Work
Special Interest: Field-Based Teaching and Learning
Grade Level: College Lower (13-14), General Public, High School (9-12), Middle (6-8)
Theme: Teach the Earth:Teaching Topics:Water, Teach the Earth:Enhancing your Teaching:Teaching in the Field, Teach the Earth:Course Topics:Sedimentary Geology, Ecology, Hydrology/HydrogeologyKeywords: turbidity, TSS