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Watershed Study - Purpose


 The first phase of the study will be completed in the winter or previous fall. Leaves representative of those in the surrounding woodland will be collected from the area adjacent to the stream.  These will be added to the experimental segments in phase two.

Leaf sampling and collecting

Toss the hula hoop over your shoulder.  Identify all the leaves within the hoop using the tree key.   Follow the steps until you arrive at the correct species for the tree.   Repeat the process at a new location.  List the frequency for each species.  Calculate the percent for each species.  Using a rake collect all the leaves within a three meter radius of the center of the hoop.  Scoop the leaves into the leaf bag.

Phase two will be completed in the spring.  Four pools will be randomly  selected for study.  Two of these pools will be control segments without leaves and two will be experimental segments with leaves.  Each segment will have a one-by-two meter rectangle designated as the sample area.

Water sampling


Collect a clean water sample from the center of each pool.  Follow the directions and determine dissolved oxygen, nitrate, and pH.  Use a thermometer to measure the temperature at the center of the pool.  Using a ruler, measure the depth of the pool at the center.


Macroinvertebrate sampling.  Use a D-net to sample the benthic (bottom) habitat.  Place the bottom of the net on the surface of the substrate.  While twisting the net back and forth, force the net upstream for one meter.  Empty the contents of the net into plastic dish pans.  Rinse the net with clean water until all of the debris is emptied into the pans.  Repeat for the second meter. This should be done for all four pools.  Keep the samples separate!  Samples will be returned to the lab for identification.  Carefully search through all leaf and rock debris.  Using forceps or eyedroppers, place specimens in small sample vials with a small amount of clean stream water.  Pour specimens with water into petri dishes or watch glasses and place them on the stage of a dissecting microscope.  Do not disturb the sample and allow all sediment to settle out.  Observe the specimens under the microscope.  Use the appropriate identification key to identify the specimen.

A stream quality index (SQI) will be determined for comparison of different sites.  Taxa (roughly defined as types of organisms) are assigned to one of three pollution tolerance groups each with a group value.  The number of taxa in each group is multiplied times the group value to get group index values that are added to get the stream quality index (Perry et al., 2002).

Preparing the experimental and control segments

Spread about one cubic meter of leaves evenly over each experimental segment.  Carefully, place the one-by-two meter nylon netting over the leaves in about the center of each segment.  Stake the netting down at the corners, along each side, and in the middle.  Place one-by-two meter netting over the two control segments and stake them down as with the experimental segments.

In phase three, about twelve weeks later, each site will be sampled.  Nitrate tests, pH, and dissolved oxygen tests will be performed on water samples from each site.   The netting will then be removed. At this time macroinvertebrate sampling will be done and a stream quality index (SQI) will be determined for comparison of different sites.  

Abiotic Sampling (as in Phase Two)

Biotic Sampling (as in Phase Two)

Dr. Stephen Reinbold

Last Modified: 6/1/18