After months of monitoring water quality in Edmonds, the Edmonds-Woodway High School-based Students Saving Salmon group presented their results to the Edmonds City Council study meeting Tuesday night.
While the report was interrupted by a downtown Edmonds power outage, the students were able to convey most of the results of its citizen science project, called the Edmonds Stream Team, to monitor water quality in the Edmonds Marsh, Shellabarger Creek, Willow Creek and Shell Creek.
From October 2015 to May 2016, during the first two weeks of each month, four teams of two to four students visited 16 sites in Edmonds, collecting water quality measurements. The stream team’s work was initiated because water quality data from Edmonds streams and the marsh is lacking and there are concerns about the health of the streams and how stream water quality, including stormwater, may be affecting aquatic organisms and salmon.
Students monitored and collected data on upstream and downstream sites for water quality parameters that are important for aquatic organism survival. Water samples were also collected seasonally for lab analysis for dissolved metals, petroleum-derived compounds, and fecal coliform bacteria. In addition, the students performed macroinvertebrate sampling and identification at upper Shell Creek, assisted by staff from Sound Salmon Solutions.
Students collected measurements for water temperature, dissolved oxygen, oxygen saturation, pH, conductivity, specific conductance, total dissolved solids, salinity and nitrates. Monitoring site data including air temperature, water depth, stream width, clarity, vegetation; and bottom substrate were also collected. All data were recorded on a standardized data sheet and then entered into a Google Drive database. Quality control measures included filed monitoring protocols, repeat samples and review/editing of database entries. The database is available to the public here.
The recorded measurements were evaluated against the Washington State Water Quality Criteria for freshwater aquatic life.
Among the students’ findings:
– Average water temperatures in the three creeks ranged from 51.0 F in the fall to 49.1 F in the winter to 53.8 F in the spring. These temperatures are below the maximum temperature requirement of 60.8 F for salmon in the Washington Administrative Code. Summer temperatures will be assessed when collected.
– Dissolved oxygen levels in the three creeks ranged from a low of 9.3 mg/L to a high of 12.5 mg/L, well above the one-day minimum requirement of 8.0 mg/L in the Washington Administrative Code (WAC) for salmonid spawning, rearing and migration. The students noted that they held Shell Creek to a higher standard for dissolved oxygen levels, because salmon do spawn in the lower reaches of the Shell Creek. Salmon eggs in the gravel in the winter in Shell Creek require higher dissolved oxygen levels than specified in the WAC to grow and hatch. The dissolved oxygen levels measured in lower Shell Creek were 11.0 mg/L in November, 11.4 mg/L in December, 11.2 mg/L in January and 12.1 mg/L in February, within optimum levels necessary for chum salmon eggs.
– The pH level in the three creeks generally stayed constant through the eight months averaging pH 7.7 except for a December decline in all streams down to an average pH 7.2, probably caused by heavy rainfall since rain tends to be more acidic (pH 5.6) than stream water. All of the observed pH levels in the creeks were within the pH 6.5 to 8.5 range suitable for salmon.
– Nitrate levels in all three creeks were low,averaging 1.3 mg/L for six months (October to March) with a high of 2.3 mg/L in February (which was also the month with highest average nitrate levels at 2.0 mg/L).
– The main water body flowing through the Edmonds Marsh (from Shellabarger inlet at the Hwy 104 culverts to the Marsh outlet) had dissolved oxygen averaging 9.4 mg/L that exceeded minimal requirements for all months with a high of 11.3 mg/L in April and low of 7.9 mg/L in October. However, dissolved oxygen measured on the northern edge of the marsh along Harbor Square was too low (averaging 1.8 mg/L) for salmon survival in all months except March, when it increased to 7.1 mg/L.
– Water temperature at all sites in the marsh exhibited the expected trend of decreasing temperatures in the fall (average 54.2 F from October to early December) with winter lows (average 47.6 F for January to early March) and increases into spring (average 58.5 F from April to May).
– The edges of the Edmonds Marsh along Harbor Square were more acidic (average pH 6.61) than the main flow through the marsh from the Shellabarger inlet at the Hwy 104 culverts to the Marsh outlet (average pH 7.31) in all months. One site along Harbor Square in January had a measured pH of 6.47, and that was the only marsh site that wasn’t within the Washingon Water Quality Standard of between pH 6.5 and pH 8.5.
– Salinity measurements at the Marsh outlet (which is representative of the main body of the Marsh) from December to early March (averaging 0.14 ppt) reflect the low salinity of the incoming freshwater from the Shellabarger inlet and lower Willow Creek (both having average salinity of 0.11 ppt for all months). But, when the tide gate is secured open (from mid-March to mid-October), the salinity measurements were significantly greater in the Marsh with 9.76 ppt salinity in October, 6.8 ppt in April and 3.2 ppt in May.
“The ecological functions and environmental benefits of this estuarine wetland would be enhanced by keeping the tidegate secured open year-round and moving forward with the Willow Creek daylighting project to open a tidal channel to Puget Sound that will allow full and uninhibited tidal exchange in the Edmonds Marsh,” the student report said.
– Water samples for fecal coliform bacteria analysis were collected from 14 monitoring sites in February and 11 sites in April. The lower Shellabarger Creek, the Shellabarger Marsh, the Shellabarger inlet to the Edmonds Marsh, and the Edmonds Marsh outlet sites all had counts of fecal coliform bacteria exceeding 100 colonies/100 mL in one or both months sampled. In contrast, the upper and lower Willow and Shell 5 Creek sites had an average fecal coliform count of 29 colonies in Shell Creek and 10 colonies in Willow Creek.
“Although there are no Washington Water Quality Standards for fecal coliform for freshwater aquatic life, the high levels observed may exceed the Washington criteria for water contact recreation (i.e., levels must not exceed a geometric mean value of 100 colonies/100 mL in areas used by swimmers),” the report said, “thus indicating a potential water quality problem (even though these waters are not used by swimmers). Further, and likely more intense, sampling for fecal coliform is needed to better understand the elevated fecal coliform levels in Shellabarger.”
– Water samples for dissolved metals were collected in the fall (October 2015), winter (January 2016) and spring (April 2016) from lower creek sites and the Edmonds Marsh. All sites had very low levels of arsenic, cadmium, chromium, cooper, iron, lead, and zinc detected in the samples. Mercury was not detected at any of the sites. Iron (which was analyzed only in the winter samples) and zinc had higher levels detected than the other metals, but the levels were below the Washington standards.
– Water samples for petroleum-derived compounds were collected in the fall (October 2015), winter (January 2016) and spring (April 2016) from lower creek sites and the Edmonds Marsh. Total petroleum hydrocarbons (TPH) were detected at all sites sampled in all three seasons (fall, winter and spring). For those sites sampled in all three seasons, they each had all three types of petroleum hydrocarbons – diesel, oil, and volatile range – detected in at least one of the season samples except the lower Willow Creek site, which had no volatile range TPH detected in any sample. Lab analyses for polycyclic aromatic hydrocarbons (PAH) were limited to five samples from the Marsh outlet in all three seasons (fall, winter, spring) and at lower Willow Creek and the eastern Marsh edge in the fall due to the cost of the lab analysis. None of the 18 types of PAH analyzed for were detected at levels greater than 0.016 g/L.
– Stream biomonitoring using the presence of benthic (bottom dwelling) macroinvertebrates as a biotic indicators of stream health and water quality was conducted in upper Shell Creek in early May. Macroinvertebrates (i.e., insect larvae, crustaceans (amphipods, isopods) and mollusks (snails) that are visible to the naked eye) were collected and identified. Since some benthic macroinvertebrates cannot survive in polluted water while others can survive or even thrive in polluted water, the presence/absence of the different macroinvertebrates was used as a relative indicator of water quality. About 15 different macroinvertebrates, with varying pollutant tolerance, were found in the Shell Creek sample resulting in an index rating of “good” water quality.
“The first eight months of the project has demonstrated that a citizen science project utilizing volunteer high school students can be successful in collecting high quality scientific data while providing students hands-on experience in conducting field science,” the report noted. “The current water quality monitoring project should continue is so annual trends can be evaluated and baseline information established. Having a long term data series will allow for future comparisons to potential environmental or pollutant driven perturbations and potential effects of climate change.”
The reported concluded it was important that the water quality of Shell Creek remain optimal for its wild spawning run of chum salmon. “Other creeks, such as Shellabarger Creek, although impacted by development and piped channels, also needs to have good water quality not only for potential salmon use in remaining usable salmon habitat, but to ensure the watershed contributes to good water quality in downstream areas such as the marsh and Puget Sound.”
You can read more in the full report available here.
For several months, the students have been collecting data monthly at 16 field sites, creating informational materials and news articles, and making presentations at community meetings.
The council will also discuss three proposed changes to city ordinances, requested by the Edmonds Police Department, that would allow officers to cite drivers for inattentive driving, clarify language and penalties for misusing the 911 system, and require that animal bites be reported within 24 hours.
In addition, the council will discuss the following:
– A change order with Razz Construction, Inc. for the Fishing Pier Rehabilitation Project.
– Presentation on the Stormwater Code Update.
– Presentation of bid results for the 76th Avenue & 212th Street Intersection Improvements Project
– Presentation of a Supplemental Agreement with KPG for the 236th Street Southwest Walkway project.
– Whether to dissolving the Edmonds Library Board, as most of its functions are being provided by Friends of the Edmonds Library.
– Changes to the code governing the Citizens’ Tree Board.