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, 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: Middle (6-8), High School (9-12), College Lower (13-14), General Public
Theme: Teach the Earth:Course Topics:Ecology, Sedimentary Geology, Hydrology/Hydrogeology, Teach the Earth:Teaching Topics:Water, Teach the Earth:Enhancing your Teaching:Teaching in the FieldKeywords: turbidity, TSS