December 10, 2004
Monitoring the water quality of restored Doan Creek
My initial interest in this internship was due to its focus on my field of study, chemistry, and also its involvement in watershed restoration. The original description of the internship was to work with Roger Trick at the Whitman Mission National Historic Site to monitor the chemical conditions of the restored Doan Creek. The collected data would be used to determine the overall water quality and whether or not the creek is suitable for sustaining wildlife, particularly fish. It also would form a basis for comparison for water quality data collected in the future in any of the Mission 's waterways.
The original path of Doan Creek runs through the grounds of the Whitman Mission. For over 70 years, the creek's course has been routed for irrigation purposes to a ditch leading to farmland, leaving the original upper portion of the creekbed dry. This portion was no longer a suitable habitat for fish and other wildlife because the water was used for irrigation. Last year, a project was approved to be implemented this fall that would restore Doan Creek to its original path. The addition would connect Doan Creek to Mill Creek and also provide for future passage route for fish.
The digging of the channel was started and completed during the first week of October. Water was kept out of the restored creek by a board placed in the diversion box at a fork in the irrigation ditch. Roger later learned that water would not be allowed freely into the creek until fall 2005. The original restoration plan included the planting of native trees and shrubs to provide shade along the creek and increase the likelihood of future wildlife inhabitation. Preventing this, is an evasive plant, Canary Grass, which needs to be controlled for an extended period before the planting can begin. Because the restored portion of the creek was being constructed during the course of my internship, I began with sampling the other sources of water at the Whitman Mission NHS, including the irrigation ditch, the on-site Mill Pond, and the original portion of Doan Creek.
Tests were performed directly on the water with the instruments that Roger provided to me, a portable microprocessor turbidity meter and a dissolved oxygen meter which also detected temperature. The pH level was measured using colorpHast pH strips. According to the Environmental Protection Agency (EPA) in their recommended elements of a state monitoring system, these are the appropriate characteristics to be tested in order to determine the feasibility of the stream as a habitat for fish. On our second meeting, Roger and I determined 7 different testing locations in a variety of areas. After the creek was completed, an eighth testing site was added to our weekly rounds. We eliminated our second site from our rounds after a few weeks due to its similarity to the first site. Although much of our time was spent determining how to calibrate and accurately operate the two instruments, we were able to collect data from all testing sites on five occasions.
On our last meeting, Roger gave me a packet on water quality standards for the state composed by the Washington State Department of Ecology. All of the water tested at the Whitman Mission NHS, with the exception of Mill Pond, was well within the standards for salmon and trout rearing and migration outlined in the packet. I was especially pleased with the quality of the readings in the restored portion. The turbidity of the water was low and the dissolved oxygen was higher than the irrigation ditch, both conditions which are sustainable for fish. The high dissolved oxygen level can most likely be attributed to the thick layer of algae growing on the creek floor. The algae can be expected to disappear once the water flows more rapidly through the creek as algae grows in warm, standing water. Even though the stream will change before fish will inhabit it, the current water quality is a positive start in the right direction.
Overall, this internship was a valuable and enjoyable experience for me. Roger was always flexible in our Friday meeting times and was easy to work with. The weather also cooperated for the majority of our collections dates. Although I expected to learn about determining water quality and the process of stream restoration, my most important lesson was a more general one in data collection. During the course of the internship, I began to doubt the validity of our readings. Although the manuals of both instruments outline the procedure for calibration, there are many other factors which could contribute error. With no previous data of this sort on the tested areas, I had nothing by which to judge the accuracy of our readings. Because the testing is done in the field, I tended toward the belief that I did not need to be as careful in sampling as I would be in my laboratory courses at Whitman College . Even so, I realized that I should not underestimate the abilities of these instruments.
The errors which I have experienced in using the turbidity and dissolved oxygen meters have not been greater than problems I have encountered in my instrumental analysis laboratory which uses much more expensive and complicated instruments. From this I concluded that I should maintain the same amount of care regardless of the testing equipment. Even so, this was difficult to accomplish without greatly increasing the time required for sampling. I came across a document from the EPA outlining the specific procedures for accurately testing all of the conditions which I have been monitoring. An example of this was washing all sample jars with phosphate-free detergent and rinsing them 6 times prior to collection. When I mentioned these guidelines to Roger, he seemed to suggest that our work did not require that degree of accuracy and precision. After we obtained more full sets of data without great variation, I felt more confidence in our readings and understood his opinion. In an ideal situation, with all of the materials and time available to us, I would have liked to have been more careful, as the accuracy of my test results are actually more crucial than anything I have done for class because my work was for the National Park Service, not for a grade.
My work testing Doan Creek is the just the beginning of an extended task. Because my tests were the first performed of these specific water characteristics, it will be useful to monitor the creek, pond, and irrigation ditch and obtain complete data for an entire year rather than for the short 5 week period. At least one full year of data would help to account for seasonal and weather changes in future comparisons. Increased sunlight on the stream increases the amount of dissolved oxygen in the water as well as causing temperature changes. To account for this, I also suggest surveying the water quality every hour for a few full days to account for differences as the day passes. I plan to continue with this internship with Roger next semester to continue the testing, building the foundation for future comparison and improving accuracy.
Whitman Mission Historic Site
328 Whitman Mission Road
Walla Walla , WA 99362