Using a Secchi Disk or Transparency Tube
http://www.epa.gov/owow/monitoring/volunteer/stream/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:Field Activity, Lab Activity, Scientific Resources:Overview/Reference Work
Special Interest: Field-Based Teaching and Learning
Grade Level: General Public, Middle (6-8), College Lower (13-14), High School (9-12)
Topics: Biosphere:Ecology, Ecology:Habitats:Water Column, Hydrosphere/Cryosphere:Surface Water:Water Quality/Chemistry, Earth surface:Sedimentary Geology:Sediment Transport and DepositionKeywords: turbidity, TSS