Stream Monitoring Handbook

This handbook is designed to be an overview of stream monitoring information. It is NOT designed as a replacement for lab and field training sessions. If you would like additional training or have any suggestions about other materials that would be helpful, please contact the coordinator.

It is easy to forget some details when monitoring quarterly. Although you are a certified monitor, you may want some review of the details of sampling and identification. You are encouraged to join other monitors or invite other monitors to join you. If you ever have any questions, please do not hesitate to contact the coordinator.

This handbook is broken into four sections: safety, equipment, biological and chemical monitoring information, and common benthic macroinvertebrates.




Before Monitoring:

  • If you would like some additional helpers, please contact the coordinator.
  • Make sure that someone knows the date, time, and location that you will be monitoring so that if you are injured, someone will know that you are missing or late in returning.
  • Find out the phone number of the nearest medical center to your monitoring site and the location of a pay phone should you need to call for help. Cell phones often do not work in stream valleys. You may have to climb to the top of the ridge to get reception.

Rules to Monitor by:

  • Never monitor when the water is at flood stage or is flowing much swifter than normal. It is better to delay your monitoring event than to risk drowning or broken bones.
  • During monitoring, keep your hands away from eye and mouth areas. ALWAYS WASH YOUR HANDS THOUROUGHLY WITH SOAP AND WATER AFTER MONITORING. NEVER EAT WITHOUT WASHING YOUR HANDS FIRST. Many of our streams have elevated fecal coliform levels. Do not monitor your stream with open cuts.
  • If the water appears to be polluted (strong smell of sewage or chemicals, unusual colors, dead fish) please postpone your monitoring.

To protect yourself, it is advised that you:

  • Wear rubber boots or waders to keep your legs and feet dry and to minimize contact with water. Rubber boots will also offer protection from ticks. It is better to wear old sneakers than sandals because they offer protection from glass and sharp rocks in the stream.
  • Wear rubber gloves to reduce contact with water and to protect cuts from trash in the stream.



Snakes are of concern when monitoring in an aquatic environment, especially slow moving water with overhanging vegetation. Most snakes in aquatic environments are not poisonous. If you approach your site through thick high grass, thump the ground in front of you with a walking stick. Snakes will feel the vibrations and will move away. Snakes are deaf so loud noises will not scare them away. The only poisonous snake in Virginia is the Copperhead.

In case of snake bite:

  • Remain calm. Take a few deep breaths and keep movement to a minimum.
  • Remove all jewelry and watches if bitten on the hand or arm. Snake venom may cause the area to swell.
  • Have your monitoring partner call 911 for help if you suspect a Copperhead bite.



  • If you do find a tick on your skin, remove it right away. To remove an attached tick, use tweezers to grasp the tick at the skin surface.





Monitoring Kit Includes:

  • Net
  • Turbidity kit
  • Nitrate/Nitrite Strips
  • 1 large magnifier (round)
  • 3 large magnifier boxes
  • 2 small magnifier boxes
  • 1 ice-cube tray
  • 3 forceps
  • 2 paint brushes
  • Several laminated bug identification cards
  • 1 Dishpan
  • Manual
  • Thermometer
  • 2 Glass vials for unknowns

Additional Equipment that you may want to check out, add to your kit or purchase:

  • Table
  • Chairs
  • Magiscope (field microscope)
  • Waders
  • Additional Magnifiers

Taking Care of Monitoring Equipment

PLEASE TAKE THE TIME TO CLEAN THE MONITORING EQUIPMENT! Please rinse out all equipment. Please return the kit looking better than when you checked it out.

Taking care of the net:

In the field, be careful to not drag the net through areas with sharp vegetation. It is very easy to tear the nets accidentally. Remember the nets are not walking sticks - they should be carefully carried to the monitoring location. If your site is located so that you have to walk through thick vegetation, it is recommended to carry the net in a plastic bag.

After monitoring, use the flow of the water to help remove any algae or macroinvertabrates. Carefully inspect the net to make sure all the macroinvertebrates are set free.

Once home, please hose down the net. PLEASE SET UP THE NET TO DRY - they develop a unique smell if they dry in car trunks and other such places.

If there are any tears in the net, please report this to the equipment manager. If you are an equipment manager, please either fix the net or contact the coordinator.

Gilled Snail

Gilled Snail


Biological and Chemical Monitoring Information

Biological Monitoring Directions

  1. Place the net perpendicular to the flow of water immediately downstream of the sampling area. Remember that the area you are sampling and the duration is dependent on the abundance of life in your stream. You can sample areas of: 1 by 1 foot, 2 by 2 foot, or 3 by 3 foot. You can sample from 20-90 seconds. You take a maximum of 4 samples. If you are unsure, please ask for help.
  2. Weight down the bottom of the net with rocks.
  3. Sample the area for 20-90 seconds.
         - (adjustable - remember the goal is 200 bugs).
        - To sample, lift and rub underwater all large rocks.
         - Dig around in the small rocks and sediments to dislodge any burrowing macroinvertebrates.
  4. After sampling, carefully rub off any rocks used to anchor the net.
  5. Remove the net with an upstream scooping motion to keep all the macroinvertebrates in the net.
  6. Place the net on a flat, light colored surface. Pick all the organisms off the net into the ice-cube tray.
  7. Once all the macroinvertebrates are removed from the seine, count the number of organisms in the sample. If at least 200 organisms have not been sampled, another net must be collected from a different area in the same riffle or nearby riffle. The organisms from the second net will be added to the first. The length of sampling time can be adjusted depending on the number of organisms collected in the first, with the maximum sampling time per net being 90 seconds.
  8. This process is repeated until at least 200 organisms are found or 4 nets are collected, whichever is first. Each net collected must be sorted in its entirety, even if that leads to a sample of well over 200 organisms.




Chemical Monitoring Directions – Nitrate/Nitrite

The Hach Test Strip is a quick, simple, and safe way to estimate the concentration of nitrate and nitrite in stream water. Nitrate (NO3-) and nitrite (NO2-) are forms of inorganic nitrogen that are very soluble in water and are readily taken up by plants. Nitrate is more common in streams than nitrite. The nitrite result will usually be "0" in streams unless the stream is being heavily impacted by a pollution source. Once in a while the nitrate result may be "0", but usually the result will be "0-1". The nitrate result may be higher than 1, especially if the water sample is taken when (or where) there is a lot of runoff entering the stream. Results higher than 5 should be double-checked, and reported for a follow-up investigation.

Increased amounts of nutrients in surface water cause algae blooms, which in turn cause other problems for streams. Increased levels of nutrients in Fairfax County streams reach the Chesapeake Bay where they contribute to the destruction of Bay habitat and fisheries.

In Fairfax County (where agriculture has been largely replaced by suburban development), fertilizer runoff (from lawns and golf courses) is the predominant source of nitrate to streams. The presence of nitrate from fertilizer also indicates that other applied lawn chemicals directly toxic to stream ecosystems, such as herbicides and insecticides, may be running off into streams. Another chronic source of nitrate addition is the atmospheric deposition of automobile emissions to impervious surfaces. Stormwater runoff then carries the excess nutrients directly into streams.

Leakage from sewer lines running alongside or under streams can cause very high levels of nitrate, and the nitrate can be used as a marker to localize the leak. Septic systems can also leak nitrate into nearby streams. Sewage leaks can contribute harmful bacteria and viruses to streams that drain into drinking water reservoirs.


  1. Be sure to replace the cap immediately when removing a strip from the bottle. The test strips are sensitive to moisture in the air.
  2. Hold a test strip by the bare end. When dipped in water containing these nitrogen species, the pads will develop a pink color, which is matched to the color blocks on the outside of the bottle. Do not hold a wet test strip against the bottle. The water will ruin the color blocks and make them difficult to read.
  3. A test strip is dipped into the water for 1 second. You can collect a fresh water sample in a clean container or dip the strip directly into the stream.
  4. Time for 30 seconds and then look at the nitrite test pad on the strip. If there is no pink color, the test is negative, and the result can be recorded by circling the "0" in the nitrite row. If there is pink color, but it is not as dark pink as the 0.15 color block, circle the "0-0.15" option on the Sheet. If the pink color looks exactly the same as the 0.15 color block, circle the "0.15" option on the Sheet, and so on. At 60 seconds after dipping the strip, match up the nitrate test pad in the same way, and circle the appropriate option on the Sheet.



Chemical Monitoring Directions – Turbidity

Turbidity is the measure of the cloudiness of water.

Remember: It is more accurate to perform the test immediately at stream-side. To do so, you must take along a small bottle of tap water.

  1. Fill one of the cylinders to the 50 mL mark with stream water and the other with tap water. If the water appears very turbid/cloudy, fill the cylinders only to the 25 mL mark.
  2. SHAKE the bottle of Standard Turbidity Reagent vigorously to re-suspend the latex particles in the reagent.
  3. To the cylinder containing TAP WATER, use the dropper to add Standard Turbidity Reagent in 0.5 mL increments-(NOT drop-by-drop). Add 1 squirt of 0.5 mL Reagent, then use the plastic stirring rod to mix.
  4. Compare the fuzzy appearance of the black dot at the bottom of the tap water cylinder with the dot in the stream water cylinder (DO NOT try to match the color-the latex particles are white and will never match the brownish or greenish tint of most stream water). The goal is to add enough of the Standard to the tap water so that the cloudiness (as judged by the appearance of the black dots) of the tap water is made to match that of the stream water.
  5. Count the number of "squirts" required to get a match. Read the turbidity (in units called JTU) off the chart on the kit's package insert/directions. Make sure you read off the correct column-one column is for use with a 50-mL volume, the other column is for a 25-mL volume.
  6. On the reporting sheet, fill in the result and the number of squirts and test volume used. Examples: 15 JTU (3 squirts/50 mL) or 30 JTU (3 squirts/25 mL)
  7. If the stream water looks just as clear as the tap water, report the result as "less than 2.5 JTU" by circling that option on the SOS Report Sheet.
  8. If the stream water looks a little more cloudy than the tap water at the start, but when you add 1 squirt of turbidity reagent it looks like the tap water column becomes much cloudier than the stream water, report the result as "about 2.5 JTU" by circling that option on the Sheet.

Tip: If you are not sure if you have a match, add another squirt of turbidity reagent. If you can see that you've "gone over," you can feel sure that the previous number of squirts was indeed the correct number.

Note: You may interpolate your result, if you wish. For example, if the match seems like it was between squirts 2 and 3 for a 50 mL volume, you could report the result as “~12.5 JTU" (which means "about half-way between 10 and 15 JTU"). Or you could use the higher number (15 JTU) or the lower number (10 JTU); whichever one you feel is closest to the match. Any of these choices is acceptable, since the turbidity measurement is only an estimate.

Table 1: Turbidity Test Results

Number of Measured Additions Amount in mL 50 mL Graduation 25 mL Graduation
10 JTU
10 JTU
20 JTU
15 JTU
30 JTU
20 JTU
40 JTU
25 JTU
50 JTU
30 JTU
60 JTU
35 JTU
70 JTU
40 JTU
80 JTU
45 JTU
90 JTU
50 JTU
100 JTU
75 JTU
150 JTU
100 JTU
200 JTU


Common Benthic Macroinvertebrates:

Below are illustrations and pictures of common benthic macroinvertebrates. As you can see, some macroinvertebrates can be easily confused because they look very similar! Be sure to take care in identifying your macroinvertebrates so that you do not confuse any of them.

Descriptions have been provided under each picture to help distinguish the benthic macroinvertebrates from each other.

Three Tails
Gills on sides of abdomen
One set of wing pads
Legs stretched to the sides
Six legs
Two Tails
No gills on abdomen
Two sets of wing pads
Legs stretched to the sides
Six legs
Two brushy tails, with hooks (usually)
If have gills, gills are underneath abdomen
No wing pads
Legs held in front of body
Six legs
Other notes: Lots of variation. Some will be in cases, some will be fat and fleshy, some thin. Most common one is pictured above. It is a free-living caddisfly (no case) and will have three hardened plates.
Midge Fly
Midge fly
No gills
No wing pads
Proleg held under body
One proleg
Long, thin body - does not thicken at end
Head clearly visible - no projections from head
Tend to "convulse" when moving
Black fly
Black Fly
No tails - have a suction pad instead
No gills
No wing pads
Proleg held under body
One proleg
Body thickens into a rounded abdomen
Head has mouth brush
Tend to attach to surface
Crane fly
Crane Fly
No tails - fingerlike projections instead
No gills
No wing pads
No legs
Thick, caterpillar-like body
Body often semi-transparent
Beetle Larvae
Beetle Larvae
No tails - but gills often pulse in and out
Gills are sometimes found on end
No wing pads
Legs held in front of body usually

This project was initiated by the Northern Virginia Soil and Water Conservation District (NVSWCD).

This information was designed for students, citizen volunteers, and others interested in benthic macroinvertebrates and/or biomonitoring to provide assistance in identification of specimens and to provide information on the habitat and general ecology of common benthic macroinvertebrates.

All drawn images are from Aquatic Entomology: the Fishermen's and Ecologist’s Illustrated Guide to Insects and Their Relatives (McCafferty 1981).

The picture of the stonefly is from the Pekin High School River Watch program.

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