Stream Assessment

OBJECTIVES

To assess the stream habitat of one reach within Ten mile Creek
To determine if there are any limiting factors in your reach of stream, with respect to habitat

BACKGROUND

Physical Habitat Measurements

Stream habitats provide fish and other aquatic organism’s places where they can find the physical and chemical features needed for life. Habitat features include water quality, spawning sites, feeding areas, and migration routes. Habitat quality affects fish abundance and size as well as species composition. Measurements of the physical habitat within a stream provide an assessment of habitat complexity, amounts of hiding cover for fish, stream depth, width, and substrate type. These variables dictate which species will be present in a given stream reach and which ones will not.

One goal of habitat analysis is to inventory current habitat conditions. This type of information can be useful for management purposes because it provides an information baseline from which management decisions can be made. Habitat analysis may identify a limiting factor, such as poor spawning gravel that can be corrected or improved through carefully designed manipulations of the stream system.

EXERCISE

We are going to follow a modified (by your instructor) version of the EPA’s “Rapid Bioassessment Protocols for Use in Wadeable Streams and Rivers” for this lab exercise. Make sure you look at this website to help you with this lab.

I have selected this exercise because I believe it to be one of the best and as many of you progress in your careers you may be asked to monitor stations for habitat, fish, and stream insects as well as to establish volunteer monitoring programs, so here is a good example to work through.

Our class exercise is broken up into two parts: a basin/reach assessment and an instream assessment.

Most of the basin/reach assessment will be performed using maps and data derived by your instructor using available GIS data for the watershed.

Stream Assessment – Physical Characterization/Water Quality Field Data Sheet

FRONT SIDE OF DATA SHEET

Work through this data sheet to provide background information about your specific stream reach

TASK 1 Delineate the site

Using your tape measure, measure off 100 meters of stream…..this will now represent your reach. It may include pools, riffles, and runs (geomorphic channel units or GCU’s).

TASK 2 Sketch your site on the field data sheet

On the field data sheet, sketch the 100-m section of stream (see Fig. 1 for example). Drawing the map will familiarize you with the terrain and stream features and provide you and others with a visual record of your reach. You should walk the 100-m length from at least one bank. On your sketch, note features such as riffles, runs, pools, ditches, wetlands, dams, riprap, outfalls, tributaries, landscape features, jogging paths, vegetation, and roads. When such features are encountered, measure the distance within the reach, so that you can accurately delineate the site. If you have a camera, snap some pictures too.

Figure 1 – Example of stream sketch

Include stream name, date, and county (or appropriate local designation) of your site, and describe its location as precisely as possible.

Latitude and longitude information is critical for mapping and for many data management programs, so record this from a handheld GPS unit.

Stream Assessment – Physical Characterization/Water Quality Field Data Sheet

BACK SIDE OF DATA SHEET

Check the appropriate boxes for WATERSHED FEATURES and RIPARIAN VEGETATAION (note this is a distance of 18-m away from bank full flow)
Under INSTREAM FEATURES, record length as 100m
To obtain stream width, take 5 randomly selected cross-sectional measurements and take an average to determine the mean stream width
To calculate SAMPLING AREA, multiply stream width (100 m) X mean stream width (m).
To determine STREAM DEPTH, take 20 randomly selected measurements and determine an average
To determine SURFACE VELOCITY, measure off 10m within your reach and time how long it takes a ping pong ball to cover that distance. Repeat this measure 3 times and take and average.
To determine the HIGH WATER MARK stretch a tape across the stream at its highest point and estimate the height.
To determine the % Riffle, % Pool, and % Run – use a tape measure to estimate the surface area occupied by each GCU within your 100-m reach
Pools, riffles, and runs. A mixture of flows and depth and provide a variety of habitats to support fish and invertebrate life. Pools are deep with slow water. Riffles are shallow with fast, turbulent water running over rocks. Runs are deep with fast water and little or no turbulence.
Under LARGE WOODY DEBRIS
Measure the length and diameter of all pieces of LWD within your reach. If none is present, mark a 0
If LWD isn’t physically in the stream, but is adjacent to it (ie., in the flood plain), measure it as it may be part of the stream during high flow conditions.
Under AQUATIC VEGETATION
Note any aquatic vegetation present within your 100-m reach
Under WATER QUALITY
Use the instructors HYDRO LAB to determine field measurements for
Temp
Conductivity
DO
pH
Turbidity
Check all other boxes that apply to your reach
Under SEDIMENT SUBSTRATES
Check all items that apply to your reach
Under INORGANIC SUBSTRATE COMPONENTS
Use the PEBBLE COUNT method to tally substrates within each of the size classes provided (use the attached data sheet)
Calculate the % Composition in your reach
IGNORE THE SECTION MARKED ORGANIC SUBSTRATE COMPONENTS

Habitat Assessment Field Data Sheet – Low Gradient Streams

Utilizing the data that you have gathered above, rate your stream section as quantitatively as you can using the scaled criteria provided.

In addition to the EPA RBP assessment described above I would like to you do perform three cross-sectional profiles of your stream reach.

Stretch your measuring tape across the stream at the height you have designated as “floodplain”.
Pin the tape with a stake so that it stays in place while you/your team evaluate stream depth.
Record the total length (ie., cross section) of tape stretched out
Using the depth pole provided, take 10 evenly spaced depth measurements across the stretched tape. Make sure you record the depth and the position along the stretched tape for each measurement.
Assume the bankfull width has a depth of 0.
Using these data plot your results in EXCEL using the line-graph feature to estimate the shape of the stream bottom.

Questions to address in your results and discussion section

(Remember this will be combined with your fish survey as well)

Habitat Evaluation Report

Include a summary of your reaches habitat evaluation
Include pictures and your sketch
Include the final rating scores from the evaluation form
Include a graph of your stream reaches pebble count and three cross-sectional areas
Discuss the potential management implications of your findings?
If you were in charge of the habitat of Tenmile Creek, what might you study next? or recommend be improved in the stream? Why?
Do you think the bridge is good or bad for the stream?

** Make charts or tables of the data to help better explain what you collected.