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What’s In Your Water? – Water Quality Testing (JHARVNC)

Laboratory and Hands-on Activities - Collection / Sampling
Laboratory and Hands-on Activities - Food Chain / Web of Life
Wildlife - Invertebrates/Insects
Macroinvertebrates are used as indicators in water quality. A quick look at what types are present can give participants an idea of the overall health of a body of water.
Grade Level2 - 12
Recommended SettingEdge of Wells Lake (or other body of water)
LocationJanet Huckabee Arkansas River Valley Nature Center, Fort Smith
Education Program Coordinator, 479-452-3993
Duration45 minutes
Suggested Number of Participants20 - 30
Special Conditions
This is a water activity, and may be dependent on weather and water conditions.
  • Find and observe macros in their natural habitat.
  • Compare and observe tolerant species versus intolerant species.
  • Learn field sampling and identification techniques.
  • Discuss what affects water quality.
Key Terms*

Food web



Life cycle





Water quality



Collection nets

Hand lenses or viewing scopes (optional)

Identification cards and/or guides


The term macroinvertebrates refers to those animals that lack an internal skeleton and can be seen with the naked eye. Examples of aquatic macroinvertebrates are mayflies, stoneflies, dragonflies, rat-tailed maggots, scuds, snails and leeches. These animals live in the water for all or part of their lives, so their survival is related to the water quality. Environmental stressors can impact macroinvertebrate populations. If there is a change in the water quality because of water pollution or a change in the water flow, then the macroinvertebrate community may also change. The following outline will introduce the importance of using macroinvertebrate populations to determine water quality.

Adult Insect Characteristics

  • More than 80,000 species of insects
  • Exoskeleton
  • Body divided into three sections: 1) head – location of mouth, eyes and two antennas 2) thorax – location of three pairs of jointed legs and one or two pair of wings 3) abdomen – location of the reproductive and digestive organs

Insect Life Cycles

  • All go through a series of changes during their life cycle. Most aquatic insects remain underwater in egg and immature stages, leaving stream as adults only.
  • Complete metamorphosis
    • Egg to larva to pupa to adult
    • Beetles, caddisflies, true flies, dobsonflies
  • Incomplete metamorphosis
    • Egg to nymph to adult
    • Mayflies, dragonflies, damselflies, stoneflies and true bugs

Insect Classification

  • Insects are classified by their physical characteristics, such as movement or how they feed
  • Movement classifications
    • Clingers – clings to rocks in fast-moving water
    • Crawler/sprawlers – crawls over surfaces
    • Swimmers – actively swims
    • Burrowers – burrows into sediments on the water bottom
    • Climbers – climbs on aquatic vegetation
    • Skaters – glides on the water surface
  • Feeding group classifications
  • Scraper/grazer – scrapes or grazes algae off rocks
  • Shredder – shreds and eats plants
  • Collector/gatherer – collects food particles by gathering or filtering them from the water
  • Predator – feeds on other animals

Water Quality

  • Often affected by changes in the water quality before humans notice
  • Scientists have grouped insects by how sensitive they are to pollutants/disturbances
  • Groupings
    • Sensitive – caddisflies, stoneflies, mayflies, megaloptera, watersnipe flies
    • Somewhat sensitive – beetles, crane flies, dragonflies, damselflies
    • Tolerant – black flies, midges, true bugs
  1. Lead class out to the lake’s edge and seat them on the edge of the trail. Introduce water quality, macroinvertebrates and their habitats.
    • What are macroinvertebrates?
      • Usually we call macroinvertebrates insects, but it can include aquatic worms, crayfish, etc.
      • Focus on insects and their characteristics
      • Classify insects by their movement, feeding, metamorphosis types
  2. Explain and demonstrate collection techniques. Explain what to do with specimens (give bowls with a little water to adults), give collection area parameters with landmarks and hand out nets.
  3. Let participants collect. Make sure adults are monitoring all activity and collecting specimens from participants.
  4. Gather macroinvertebrates and have participants separate them by types and identify them. (Use ID cards to assist with classification.) Once they are identified, briefly discuss each one based on classification characteristics such as body parts for movement, mouth parts for feeding, etc. Use the ID cards as basis for this information.
  5. Discuss the insects and how they represent water quality.
  6. Discuss other tests of water quality, such as pH, DO, nitrate, phosphate, etc.
  7. Test these water quality measures if time allows, especially for older grades.
  8. Wrap up by discussing what types of macros were present, how this indicates the water condition and what could be done to improve the water quality.
  • Take participants to a different body of water to perform the same collections and identifications. What differences would they expect? Compare and contrast the findings of different species and differences in water quality.
  •  “Adopt” a body of water and conduct regular water quality tests and compare the data over time.  (Borrow a kit or apply for a grant to purchase equipment and supplies.)
  • Teachers can attend a Project WET workshop and receive a book of activities and games focusing on wetlands, water conservation, water quality and other related topics. (For workshop information, contact Philip Osborne or Barbara Miller, Arkansas Department of Environmental Quality, 501-682-0024.)
  • What conditions most likely affect the water quality at Wells Lake? Could the quality be improved? What actions could be taken to improve the water quality?
  • Does the activity in your yard/garden/farm affect the quality of a body of water near you? Does that affect the Arkansas River? Mississippi River? Gulf of Mexico? Atlantic Ocean? Why is it significant?
  • What might be an effective campaign to promote improved water quality in your area? What negative affects of pollution might inspire people to improve their habits? How could people change their behavior that would lead to improved water quality?

Food web – a network of interrelated food chains in an ecosystem

Insect – invertebrate animal of the class Insecta of the phylum Arthropoda with an exoskeleton, three sets of jointed legs, a segmented body made up of head, thorax, abdomen and typically one or two pairs of wings

Intolerant – extreme sensitivity to surroundings or substances

Life cycle – stages an organism, group or culture passes through during its lifetime

Macroinvertebrate – organism that has no backbone, lives in or on the water for all or part of its life and is large enough to be seen without a microscope

Metamorphosis – a change in the form and often habits of an animal during normal development after the embryonic stage. Examples include a maggot changing into an adult fly and a caterpillar into a butterfly, and in amphibians, the changing of a tadpole into a frog.

Pollution – introduction of contaminants into an environment causing instability, disorder, harm or discomfort to the ecosystem

Tolerant – the ability to survive in extreme conditions

Water quality – describes the biological, chemical and physical characteristics of water, based on what is suitable for human consumption and personal hygiene