Foster Creek Conservation District
Results of Water Quality Monitoring
We will continue to update this page at the end of each year! Please contact Angie Orpet if you have comments or questions at aorpet@fostercreekcd.org
We are measuring water quality to better understand long-term changes in the watershed. Water quality should improve over time as new farming techniques are implemented and as trees and shrubs within riparian restorations mature. What follows are the summaries of data collected from June to November 2018 at 4 sites in Douglas County.
Here we define the water quality variables measured. Visit this site for more information.
| Variable | What is it | Why it is important | How to change it |
| Temperature | Stream warmth | Creatures living in the stream like specific ranges; it changes rate of chemical reactions in water | Plant shading vegetation |
|
Specific Conductivity |
Ability to pass an electrical current because of minerals in the water | Tells us if there is erosion into the stream and the minerals of the streambed | Prevent soil erosion |
| pH | If water is acidic or basic (lemon juice vs. ammonia) | Changes if the water can dissolve compounds or if creatures can uptake compounds | Prevent pollution |
| Turbidity | The clarity of water changed by fine organic or inorganic matter | Fine particles can cover stream habitat or may contain pollutants | Prevent soil erosion, have plants next to the stream to block erosion |
| Dissolved Oxygen | Oxygen in water | Creatures living in the stream breathe it | Shade the stream |
A TidbiT temperature logger in a PVC tube ready for the water.
Methods:
We sampled at East Foster Creek, West Foster Creek, Deep Creek and Fiddle Creek.
We collect data with 2 tools; the TidbiT and the HL4.
The TidbiT stays in the water as long as the stream is flowing and only measures temperature.
The HL4 is placed in the water for 8 days each month and measures water temperature, specific conductivity, pH, and dissolved oxygen.
We logged the water temperatures with TidbiTs at 15 sampling locations starting June 2018. One logger was placed in a tree near the stream to measure air temperature at each site. TidbiT loggers were removed for the season in November.
Two HL4 probes in the water connected to an instrument that reads the results
TidbiTs and HL4s measured 48 values each day because they took a measurement every 30 minutes. We averaged these (gray) and recorded the daily minimum (blue) and maximum (orange) values. These values are graphed for the HL4s (see graphs below).
Under Washington legislation (WAC 173-201A0600), West Foster Creek is designated as protected for “salmonid spawning, rearing, and migration.” Salmonids are considered a “cold water” fish and, for healthy spawning, prefer the following parameters:
- Water temperature (highest 7-day average) - maximum no greater than 63.5° F
- pH – between 6.5 and 8.5
- Dissolved oxygen – not less than 8 mg/L
These limits are indicated by the straight red lines in the graphs below. If one or more of these parameters are not met, it may be detrimental to salmon and other aquatic life. Our ongoing monitoring program will help us understand the baseline, changes made by riparian restoration activities and land use, and help guide planning for future projects.
Findings:
TidbiTs
We found that during July and August, Deep Creek TidbiTs' had the lowest median water temperatures (56°F) and East Foster Creek had the highest median water temperatures (62°F). All four streams had maximum temperatures higher than standard Washington State 7-day average maximum temperatures for “salmonid spawning, rearing, and migration.” Ninety percent of measured temperatures at Deep Creek and Fiddle Creek were under the maximum allowed temperature, where almost half of East Foster temperatures were above the maximum allowed.
Maximum, 10th and 90th percentiles, and median temperatures between July and August 2018 for TidbiT loggers. Red line shows the state allowable maximum temperature.
HL4 - East Foster
- Temperature – On average, daily stream temperature was 51° F with June, July and August exceeding daily maximum temperatures (Graph 2).
- Conductivity - The average specific conductivity was 831 µS/cm2 (Graph 3).
- pH - The water was slightly basic as expected for arid conditions with an average pH of 7.81 (Graph 4).
- DO - Minimum daily dissolved oxygen was just below the desired 8 mg/L during the hot months, but rose above 8 mg/L in October and November (Graph 5).
- Turbidity – The waters were clear at an average 0.5 NTU and there were occasional spikes around 10 NTU. For comparison, drinking water is ideally below 1 NTU (Graph 6).
HL4 for East Foster Creek in Douglas County
HL4 - West Foster
- Temperature – On average, daily stream temperature was 52° F. Measurements before October exceeded the Washington State standard (Graph 2).
- Conductivity - The average specific conductivity was 639.3 µS/cm2 (Graph 3).
- pH - The water was slightly basic, as expected for arid conditions, with an average pH of 8.14 (Graph 4). Three of five measuring periods exceeded the Washington State standard of pH 8.5.
- DO - Minimum daily dissolved oxygen was below the desired 8 mg/L in June, July and August, but rose above 8 mg/L in October and November (Graph 5).
- Turbidity – The water was an average 4.3 NTU excluding outliers. For comparison, drinking water is ideally below 1 NTU (Graph 6).
HL4 for West Foster Creek in Douglas County
HL4 - Fiddle Creek
- Temperature - On average, daily stream temperature was 49° F (Graph 2).
- Conductivity - The average specific conductivity was 428.8 µS/cm2 (Graph 3).
- pH - The water was slightly basic as expected for arid conditions with an average pH of 8 (Graph 4).
- DO - Minimum daily dissolved oxygen was above the desired 8 mg/L at an average of 9.8 mg/L (Graph 5).
- Turbidity – The water was an average 6.3 NTU excluding outliers. For comparison, drinking water is ideally below 1 NTU (Graph 6).
HL4 for Fiddle Creek in Douglas County
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