Vernier Software and Technology
Vernier Software & Technology

Watershed Testing

Figure from experiment 27 from Agricultural Science with Vernier

Introduction

There are many reasons for determining water quality. You may want to compare the water quality upstream and downstream to locate a possible source of pollutants along a river or stream. Another reason may be to track the water quality of a watershed over time by making measurements periodically. When comparing the quality of a watershed at different times, it is important that measurements be taken from the same location and at the same time of day.

In 1970, the National Sanitation Foundation, in cooperation with 142 state and local environmental specialists and educators, devised a standard index for measuring water quality. This index, known as the Water Quality Index, or WQI, consists of nine tests to determine water quality. These nine tests are; temperature, pH, turbidity, total solids, dissolved oxygen, biochemical oxygen demand, phosphates, nitrate, and fecal coliform. A graph for each of the nine tests indicates the water quality value (or Q-value) corresponding to the data obtained. Once the Q-value for a test has been determined, it is multiplied by a weighting factor. Each of the tests is weighted based on its relative importance to a stream’s overall quality. The resulting values for all nine tests are totaled and used to gauge the stream’s health (excellent, good, medium, poor, or very poor).

For the purpose of this exercise, you will perform only four of the WQI tests: water temperature, dissolved oxygen, pH, and total dissolved solids. A modified version of the WQI for these four tests, will allow you to determine the general quality of the stream or lake you are sampling.

Objectives

In this experiment, you will

  • Use a Dissolved Oxygen, Temperature, Conductivity, and pH Probe to make on-site measurements.
  • Calculate the water quality based on your findings.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Option 1

Option 2

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Agricultural Science with Vernier »

Agricultural Science with Vernier

See other experiments from the lab book.

1Introduction to Data Collection
2Acids and Bases
3Diffusion through Membranes
4Conducting Solutions
5Osmosis
6Respiration of Sugars by Yeast
7Reflection and Absorption of Light
8Soil pH
9Soil Salinity
10Soil Temperature
11Soil Moisture
12APhotosynthesis and Respiration (CO2)
12BPhotosynthesis and Respiration (O2)
12CPhotosynthesis and Respiration (CO2 and O2)
13Transpiration
14ACell Respiration (CO2)
14BCell Respiration (O2)
14CCell Respiration (CO2 and O2)
15The Greenhouse Effect
16Energy in Food
17AEnzyme Action: Testing Catalase Activity
17BEnzyme Action: Testing Catalase Activity
18ALactase Action
18BLactase Action
19Oxygen Gas and Human Respiration
20Biochemical Oxygen Demand
21Animal Temperature
22Lemon "Juice"
23Ohm's Law
24Energy Content of Fuels
25Photovoltaic Cells
26Wind Power
27Watershed Testing
28Interdependence of Plants and Animals
29Biodiversity and Ecosystems

Experiment 27 from Agricultural Science with Vernier Lab Book

<em>Agricultural Science with Vernier</em> book cover

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