Water Quality Monitoring on Doan Creek with Roger Trick
The Whitman Mission Site is operated by the National Park Service. In the past year or two, Service employees have diverted a small stream off Mill Creek called Doan Creek, and since then have worked to make the stream habitable for salmon and steelhead.
To determine if the stream is (or will be) habitable for fish, the water quality of several sites on the creek was monitored carefully. Every Friday afternoon, I drove out to the Whitman Mission Site to take water quality measurements with Roger Trick, Chief Interpretation and Resource Manager at the site. The measurements we took included pH, dissolved oxygen, stream flow, stream dimensions, and turbidity. These data were entered into an Excel database for analysis, which included comparing our measurements from the Doan Creek samples with the Washington State Department of Ecology Water Quality Standards for Surface Waters of the State of Washington. To a large extent, these standards are based on regulating human activities that affect these stream variables. This may have little applicability to Doan Creek because it is entirely located on protected property. Nevertheless, it is good to know that the Doan Creek measurements we took are mostly within the criteria range given by DOE, which indicates that the potential for salmon in Doan Creek looks optimistic.
Taking these water quality samples has provided me with valuable experience using field tools. Although I have taken pH, dissolved oxygen, and turbidity measurements in various chemistry labs, I have always used complicated lab techniques that require a lot of equipment and a substantial amount of time. It was interesting to see the theory behind these techniques applied to technology. Although these instruments are more convenient and time efficient than lab techniques, I am dubious that they are of comparable accuracy. I am especially concerned because, while I was working at the Park, the instruments were never calibrated using lab techniques, but rather with the “self-calibration” modes which were based on entered values.
The most frustrating aspect of this internship was Roger’s ineffective use of Excel for data organization and analysis. Excel is a great program for scientific data collection and analysis if used correctly. However, Roger did not have much experience using the Excel program and relied on less efficient methods to manipulate the data (like a calculator). Thus, the database we produced is slightly confusing (because none of the formulas we used are apparent) and more simple than it could be. I recommend that a future intern, assuming they have more experience with Excel than Roger, plays a bigger role in the Excel-using portion of the internship.
Roger has mentioned extending the sample sites to include the pond on the Mission Site, which is something a future intern could be involved with. This would certainly give different data, and would make for interesting comparisons. Roger also seemed interested in the potential of collecting macroinvertebrate data. The presence/absence/populations of various macroinvertebrates can be used as direct indications of how healthy a stream is and how habitable it is for salmon and other fish. Beginning a macroinvertebrate monitoring project would involve buying expensive equipment and sending the samples off to a lab to do identification for us. This may not be realistic, depending on the Mission’s budget, but could be something for a future intern to look forward to implementing.
It seems that working for the National Park Service, whose written mission is to “conserve the scenery and the natural and historic objects and wildlife therein and to provide for the enjoyment of same in such manner as will leave them unimpaired for the enjoyment of future generations,” would be a satisfying experience. This is Roger’s second Park Service job, and he enjoys it specifically because of the diversity of material involved with his job. The Whitman Mission Site made a shift upon hiring Roger from focusing on conservation of the site with just a historical basis to conservation with a natural/ecological basis, and is now working out a balance between the two. Roger’s one complaint about his job and the Park Service in general was the amount of bureaucracy involved. This seems to be a common problem for government agencies.
As a whole, this internship was satisfying, interesting, and applicable to my environmental chemistry major. I am excited about the prospect of salmon inhabiting Doan Creek, and I hope a Whitman intern will be there to witness the changes the creek experiences.
Water Quality Monitoring Instrument Procedures
Water Flow testing:
Global Water flow probe FP 101 sold by Global Water, 11390 Amalgam Way, Gold River, CA 95670 (1-800-876-1172) (www.global.com).
The instrument is factory calibrated, with a propeller that turns as a result of the stream velocity. A battery operated computer display shows water flow velocity.
Follow directions on the laminated instruction card. Measure the width and depth of the stream at the point where the sample is taken with metal tape measure. Record on the datasheet. Depth of water is taken ¼, ½, and ¾ of the way across the channel width. Average these three measurements to obtain an average depth of the channel. Calculate the square inches of water in the channel by multiplying the channel width by the average depth of the water.
Test the flow probe prop to make sure it is turning freely by blowing on it before putting it into the water. Reset the computer to zero and then put the probe into the water. Move the bottom of the probe slowly across the entire width of the channel, back forth, so a complete cycle takes approximately 30 seconds. Keep the probe in the channel between 90 and 120 seconds, always moving across the channel. The small computer averages the water flow velocity against the elapsed time it was records to obtain an average velocity reading in feet per second, which is recorded on a worksheet. Then reset the computer to zero.
As part of the Excel spreadsheet in the computer in the office, the square inches of the channel is converted to square feet, and then multiplied by the water velocity in feet per second. The result is a number in cubic feet per second, the common unit of measurement for stream and irrigation water flow. Here is an example:
1. Width of the stream X average depth of water = water amount in square inches
2. Divide water amount in square inches by 144 to equal square feet of water
3. Multiply by feet per second of water flow from flow probe = cubic feet per second.
50 inches X 9.5 inches = 475 square inches ÷ 144 = 3.30 square feet X 0.72 feet per second flow rate = 2.38 cubic feet per second volume
At the end of the sampling period, wipe probe off, test the propeller to make sure it rotates freely, and put the probe back in its case.
Paper-based pH indicator strips were used from the beginning of water monitoring in 2004 until March, 2006, when the park began using the Hanna HI 98129 meter. The paper strips are from EMD Chemicals, 480 Democrat Road, Gibbstown, NJ 08027. They are called “colorpHast” pH-indicator strips, non-bleeding, pH range 6.5 to 10.0.
Directions for use are on the box, “Dip in – read while still moist. Immerse in weakly-buffered solutions until there is no further colour change (1 – 10 min).” A chart with different colors are at the bottom of the box and are in either 0.2 pH or 0.3 pH increments.
Place one pH test strip into the jar of sample for one minute, plus or minus 10 seconds. Pull the test strip out of the jar and compare its color to the color scale on the box, which ranges from pH 6.5 to 10.0. Record the closest color match onto the datasheet as the pH reading of the water. Do not extrapolate between two colors on the scale. For example, if the test strip color is between the 7.1 color and the 7.4 color, the pH is recorded as either 7.1 or 7.4, but not something in between the two. On the data sheet, always record the closest color match on the color/pH scale.
Next, place a second paper test strip in the same water sample for 3 minutes, plus or minus 15 seconds. Compare the color of the test strip with the color/pH scale on the box. As before, do not extrapolate between two colors on the scale, always record onto the data sheet the closest color match on the color/pH scale on the box. Record on the data sheet the 1-minute reading and the 3-minute reading in the correct columns for each sample jar of water.
Testing pH in Water Samples:
Hanna Instruments waterproof pH, EC/TDS and temperature meter, model HI98129.
The meter can be calibrated at one or two points for pH with auto-buffer recognition and against five memorized buffer values that are factory installed. All pH readings are automatically compensated for temperature, and temperature values can be displayed as either degrees Celsius or Fahrenheit.
Follows the directions on the instruction folder; see section on pH measurement and calibration.
Once water samples are brought back into the building, activate the meter and follow the directions to check pH. Place the end of the meter into the half-pint jar of water, stir the water with the instrument for 10 seconds, and wait for the reading to stabilize. Record pH reading onto the datasheet.
After the instrument is put into one sample jar and the reading is taken, rinse off meter under running tap water for 2 – 5 seconds. This ensures minimal contamination between samples. Put instrument into the next jar of water, stir the water with the instrument for 10 seconds, allow the reading to stabilize, and then record it on the datasheet.
The instruction folder contains directions for storage and maintenance under the heading pH Electrode Maintenance. Follow these directions, making sure the pH electrode is stored in a few drops of storage solution, Hanna Instruments product HI70300, Storage Solution for pH and ORP Electrodes.
Hanna Instruments Portable Microprocessor Turbidity Meter, part number HI 93703. The instruction manual contains calibration and operational information.
Wash the cuvette with Hanna anti-static solution for Cuvette Cleaning, Hanna part number HI 93703-50. Fill approximately one-sixteenth of the cuvette capacity with the cleaning solution. Rinse the cuvette with running tap water until the water is clear. At first the water in the cuvette will be sudsy, but with enough rinsing, will become clear. Next, rinse cuvette with milipore deionized water.
Rinse the inside of the cuvette twice with water from the sample jar. Fill the cuvette with water from the sample jar again. Put the black cap on the cuvette. Wipe off excess water and any external dirt, fingerprints, etc. with the blue lint-free cloth.
Put the cuvette with cap on it into the instrument and rotate it until it locks down. Push the “Read” button to obtain the turbidity in FTU.
Repeat each washing and testing sequence three times to obtain three repetitions of the turbidity reading for each water sample.