In Lesson 1 and 2, it was emphasized that Bald Eagles need to live near and hunt from unpolluted, high quality water. Water quality is sometimes difficult to determine. Some people think that if water is clear; it is clean, and if it is cloudy or colored, the water is dirty or polluted....unfortunately, it is not that simple.

The only way to determine the health of a lake or river is to test the water. This part of Lesson 3 will walk you through ten different water quality tests that you can perform on a lake, pond or river in your area. At the end of this section, you will be able to take your data and calculate the overall quality of the water you have been testing. Depending on the results, you can decide if the lake or river would be a good place for a Bald Eagle to live and hunt.

A majority of the information, charts, and tables in this section came from an excellent book titled Field Manual for Water Quality Monitoring : An Environmental Education Program for Schools. If you would like more complete information on this subject, this book would be a great resource.

Introduction

Have you ever looked into the flowing waters of a stream or river and wondered where it began, or to where it flowed? There are some features that are unique to rivers and lakes.

• All rivers and lakes have flowing water. Depending on their size and shape, the water flow might be fast or very slow.
• Rivers and lakes are inseparable from the land through which they flow. The land area that drains rain and snowmelt to a river is called a watershed. Everything that happens in a watershed affects the water quality to some degree. Every person on earth lives within a watershed. Do you know what your watershed looks like? How does land use affect your river?
• Rivers are some of the oldest natural features on Earth. Rivers stretch back in time millions of years. Just imagine the age of the Colorado River, as it has cut a channel almost a mile deep called the Grand Canyon.
• Rivers and lakes are some of the most used and abused natural features on Earth. Many watersheds have been altered as a result of human needs for water, food, recreation, transportation, manufactured foods and other amenities. These growing demands have led to pollution of streams and rivers and unwise land uses that further degrade water quality.

How to Measure Water Quality Using a Water Quality Index

Many factors can affect water quality. The conditions of a river or lake can fluctuate periodically, so you must measure water quality periodically to look for trends. Water that is determined to be safe for one use may be unacceptable for another purpose or species. This part of Lesson 3 will use biological, chemical and physical measurements to determine the health of a body of water.

The information in this part of the lesson has been divided into three main sections. You should start with "Water Quality Index." It will describe the process and what type of information you will need to collect to calculate a Water Quality Index (WQI) for a body of water.

The next section, the largest, involves information on the nine tests that go into the WQI. Each section contains background information on the tests and its significance. Detailed instructions are also included on how to perform the tests. Some of the tests have kits that can be purchased, and their instructions should be followed. If some of the tests are more involved than you prefer, maybe you can team up with a science club or a high school science class and share the information.

The information in "Calculating the WQI" will allow you to take your tests results and make a scientific conclusion about the quality of the water. Although many factors affect where a Bald Eagle lives, you will be able to determine if the water would be a positive factor in its selection of a home.

There are other ways to evaluate the quality of water. You don’t always have to use test tubes and chemicals, sometimes all you have to do is look at what critters already live there. There are some animals that can be used as indicator species. For example, black fly larva can tolerate a higher level of pollution than a caddisfly larva. Using the Critter Scorecard, you can determine the quality of the water by what type of creatures you find.

And finally, the last thing you need to do before you get started is to select a lake, stream or river you would like to test !