Material and Methods

A Vernier attached to a scientific calculator is very convenient for more flexibility in data collection. These data collectors are the preferred piece of equipment as they provide a screen for immediate feedback of results. However, without precise calibration of Vernier probes they can easily gather inaccurate readings. Six Vernier probes were used during this study each reading separately pH, turbidity, dissolved oxygen, nitrate concentration, conductivity, and a flow meter. A 100ft. surveyers measuring tape, three neutrally buoyant balls, and a stopwatch were used to manually measure water velocity. A 50 ft. surveyor measuring tape and a meter stick were also used to measure the depth at every foot across the stream for analysis of the streams cross-section. Long bolts are also recommended for fastening the loose end of the tape during cross-section data collection. Gathering macro invertebrates can be trying without the right catch net. There are several kinds the best has a metal frame and a square opening that folds down to represent the quadrant. Along with the catch net this study requires four empty 50mL containers for storing the macro invertebrates and a white tray. A field kit complete with a dropper and tweezers are essential for gathering macro invertebrate samples. Other equiptment helpful for stream collection are as follows, two empty 500mL containers for gathering sediment samples. Two empty 125mL containers for collecting water samples to measure phosphorus concentration. Colored tape, and ink pen to mark all samples for each site. A manual temperature gauge is required to measure the streams temperature at both sites. Finally, a weather monitor for reading air temperature, barometer, and altimeter reading. Calibrating each probe can be very trying but it is an essential step for getting accurate readings. For time efficiency and calibration quality the Verniers were calibrated at the field laboratory. Each Vernier probe requires a different set of calibration procedures and can easily be flawed. These procedures were followed as directed in Water Quality with Calculators in Appendix C under Remote Data Collection Using LabPro and CBL 2.

Turbidity: For calibration a two-point calibration was performed using de-ionized water as the blank and a 100NTU. The sample bottle was dipped and rinsed three times within the stream. The samples were collected at mid-reach/ mid-stream/ mid-depth. Three separate samples were taken using the above procedure to get the average turbidity.

Dissolved Oxygen: A two-point calibration was performed using DI saturated air in a closed bottle as the 100% saturation level and a sulfite solution as the 0mg/l standard. Readings were collected mid reach at the highest velocity point by dipping the probe directly into the stream. Three separate readings were taken at each site for the average dissolved oxygen concentration.

pH: For calibration a two-point calibration was performed using pH 4 and pH 7 buffers. The pH readings were collected at the highest velocity point mid-reach in the stream at each site by dipping the probe directly into the stream. Three separate readings were taken at each site for the average pH.

Nitrates: A two-point calibration was performed using a 0.5mg/L low standard and a 50mg/L high standard. Nitrate concentration was collected at the highest velocity point mid-reach in the stream at each site by dipping the probe directly into the stream. Three separate readings were taken at each site for the average nitrate concentration.

Conductivity: The probe range was set at 0-2000. A two-point calibration was performed using air as the blank and a 1000mg/L standard. Readings were collected mid reach at the highest velocity point by dipping the probe directly into the stream. Three separate readings were taken at each site for the average conductivity reading.

Vernier Flow Rate: There are no calibrations needed for monitoring the flow rate. The flow rate sensor and the conductivity sensor simply cannot be used at the same time. The sensor was placed in the stream at mid-reach at the point of highest velocity with the propeller facing upstream. A ten second average reading is then calculated using the start prompt on the menu.

Latitude/ Longitude: A Garmin eMap Global Positioning System (GPS) was used to triangulate our position at each site.

Weather: A weather-monitoring device was used to record the air temperature (degrees C), barometer reading (in.Hg), and wind reading.

Phosphates: Three water samples were collected in 125mL bottles at mid reach, mid stream, mid depth at both sites. A spectrophotometer was used for phosphate analysis. Four standard solutions were created for spectrophotometer calibration. Starting with 0 standard, .05 standard, .10 standard, .50 standard solutions calibrate the spectrophotometer. Phosphate samples are then placed into test tubes and a reagent is added to the standards and samples. The standards and samples sit for 10 minutes and then can be placed into spectrophotometer to record absorbance.

Macro-invertebrates: A surber catch net was set down in slightly riffled areas at mid- reach at both sites. With the net faced downstream the rocks were thoroughly rubbed to dislodge any macro-invertebrates. The net was then lifted from the stream and the filtrate washed into white trays. A field kit was then used to collect the macro-invertebrates and placed in 50mL containers. Upon returning to the field laboratory the specimens were then sorted and separated using macro-invertebrate keys, counted and placed in ice trays.

Streambed Sediment: Two sediment samples were collected in 500mL containers one from each site at convenient areas within the streambed. These samples were dried in a lab oven for 5 full days. The full weight of each sample was recorded and separately sieved through the following sizes: 2.0mm, 1.0mm, 500um, 250um, 125um, and 63um. The different sized sediments were then separated and reweighed. The weight of each size was divided by the total sample size to determine percent of total sample.

Water Temperature: An analog thermometer reading in Celsius was held at mid reach at the highest velocity point was used for the manual temperature readings.

Manual Flow Rate: The stream velocity was determined by measuring off a 100ft. section of the stream. A neutrally buoyant ball is floated the length of the reach and time is recorded. This procedure is completed three times to get the average flow rate. The length was divided by the float time to determine the velocity of the stream. Then measuring the width of the stream and measuring stream depth at one-foot intervals a cross section of the stream was completed. The average depth was multiplied by the width, which gives the cross sectional area. To get the flow rate this cross sectional area was multiplied by the stream velocity.

Detailed methods for identifying macroinvertebrates used by our class.

Macroinvertebrate Method

Quick macroinvertebrate key by Jason Hall:

Vernier calabration methods BBC Home

Material and Methods

Web site constructed by Chris Ringstad, Deb Bailey, and Jeffrey Elisoff, June 2003