Water Quality Monitoring for Doan Creek at the Whitman Mission National Historic Site
The National Park Service has recently recreated Doan Creek, a creek that was once used by migrating salmonids and other fish, but had long since dried up due to human water use. They have dug out the original channel, lined it with plastic where necessary, and are in the process of revegetating the creek’s banks with local plant species. Although the creek is still dry during the summer and early fall months and therefore currently not of use to fish yet, I monitored the pH, turbidity, dissolved oxygen, temperature, and flow rate of the creek and compared my data to state regulations so that the park rangers are able to see the stream’s progress.
Goals and Objectives at the Start of the Internship :
- Learn how to use measurement equipment and familiarize myself with the sampling sites.
- Measure pH, turbidity, and dissolved oxygen content at several sites at the newly restored Doan Creek every week.
- Record data on the available spreadsheets.
- Compare the data with the state standards for a habitable stream for salmon and steelhead.
- Figure out the best way to statistically represent the changes in Doan Creek data collected over the past couple of years.
- Figure out the most useful way to statistically compare the data at the sample sites.
- Report any large problems to the Natural Resource Conservation Service so they can make adjustments to their stream design.
- Take measurements of Mill Creek (which also passes through a corner of the Whitman Mission site) and compare that to Doan Creek measurements.
Logistics and Monitoring Procedures:
I spent a little over two hours at the field site collecting samples
and running tests once a week on Wednesday mornings. There are four sampling
sites along Doan Creek and we also sample at one site along Mill Creek. At each
site, Roger and I measured dissolved oxygen and temperature using a handheld
waterproof dissolved oxygen/temperature meter. We also measured flow rate using
a flow meter and a tape measure (to take the dimensions of the creek) and collected
a jar of water to test for pH and turbidity indoors. After sampling in the field,
I took the jars into the visitor’s center kitchen and use a handheld pH
meter to measure the pH of the five samples and a turbidity meter to take three
measurements of each of the samples. I recorded all of the data on a spread
I was asked to develop procedures for taking these measurements and they are as follows:
Flow Rate (in the field):
-Choose three locations across the stream and submerge the flow meter at each point for 1 min. (total of 1.5 min) to find the average flow rate.
pH test (at sink):
-Calibrate pH meter using the standard buffer solutions in marked jars (rinse electrode before and after submersion into buffers with sink water, blot extra water with paper towel)
-Submerge electrode into each of the samples and record pH (rinse with regular water in between tests)
-Rinse electrode in DI water and store in DI water when finished
Turbidity test (at sink):
-Calibrate test once a month
-Shake sample and rinse once with sample before testing
-Test three times (no need to rinse until switching samples) and wipe cuvet each time before inserting.
-Rinse once with new sample when switching to the next sample and repeat process
-Store cuvet full of DI water
We collected seven sets of data throughout the semester on the following
dates: 9/27, 10/11, 10/18, 10/25, 11/1, 11/8, 11/29(see graphs at end). Although
we tried to meet every week, Roger had to go to out of town twice and I was
out of town for Thanksgiving. Data is missing from site 4 on the first week
of sampling because the site was completely dry. Fortunately, when we next measured
two weeks later, there was a sufficient amount of water and it remained that
way throughout the semester. The last date, 11/29, was unbearably cold and we
were only able to sample from site 1 and site 2 so data from all other sites
on that date is missing as well.
Once we had all the data, we were able to compare our findings with the state regulations. According to several Washington State websites, if Doan creek is to be habitable for most fish species, the dissolved oxygen must exceed 9.5 mg/L, the temperature can not exceed 18 degrees C, the turbidity should not exceed approximately 50 FTU, and the pH must stay between 6.5 and 8.5. According to these statistics, the water in Doan Creek is suitable for salmon use. The temperature never exceeded 18 degrees C in any of our measurements. In fact, the water in Doan creek was always several degrees cooler than the water of mill creek which could actually entice fish to come into the Whitman Mission rather than continue on. The turbidity of the water is also well under the state approved maximum. Even after heavy rains on 10/18, the increase in turbidity was minimal.
Most measurements were in the range for acceptable pH, but at times the water was a bit basic in site 1 and site 4. These two sites are the last sites through which the water passes before leaving the park. Site 2, which on average has the lowest pH is the place where the water first enters the park. From this evidence it would seem that the water becomes more basic as it travels through the park. We tried to discover what could be causing this pH increase, but no sources were readily apparent. It is possible that the soil in the park is increasing the pH, but as long as the problem doesn’t worsen, there is no need to investigate the issue further. The dissolved oxygen measurements were also a little troubling, especially on 11/8. It is possible that the instrument was calibrated differently on that day because there is no reason why the oxygen levels should decrease. Dissolved oxygen generally increases when the water temperature decreases, and although the temperature did increase that week from the previous week, it did not increase dramatically enough to justify the loss in oxygen. Because these measurements were only slightly too low and only on one day of measurements, it doesn’t appear to be a huge problem. If the problem did persist, I might recommend extracting some of the vegetation from the creek bed in order to decrease the possibility of eutrophication, which can decrease oxygen levels.
Although the water in the creek has looked pretty good for a while
now, we are still faced with the problem of not having enough of it. The Doan
creek did not actually connect with Mill Creek until 11/8, after an unusually
large amount of rain and in a dryer year it is possible that the creek may never
reach Mill Creek at all. Obviously salmon will not be able to migrate up Doan
Creek if they are not able to reach it. Luckily, the park will be receiving
a large piece of adjoining farm land in the next couple of years and they will
reroute the water that is now used to irrigate those crops into Doan Creek.
I asked if they plan on stocking the stream, but as of now, they have no concrete
plans. They do have a program where they give elementary school classrooms fingerlings
to raise and then release, and they have considered letting the children release
them into Doan Creek in the next couple of years.
Although not much can be done for Doan Creek at this point, the internship was a very enjoyable experience. Not only did I learn about their stream restoration efforts, but I also learned a great deal about replacing weeds and non-native plant species with native species. Their main goal at the park is to return the land to the state it was in when it was inhabited by the Whitmans, and while the restoration of Doan Creek is a part of this effort, their main concern is still revegetation. I was also able to talk to Roger about the inner workings of the park and how they maintain their funding from the government for our project. Unfortunately, I was not able to talk to other rangers and employees at length, but Roger gave me a sense of their duties during an average workday. Although working for the National Park Service is not something that I see myself doing in the future, the internship provided me with an interesting glimpse into an institution that has played a very important role in the environmental history of the United States.