Hylebos Watershed Spring 2003

Introduction | Locations | History | Land Use | Methods | Results & Discussion | Work Cited
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Conclusion

The Hylebos Creek Watershed is clearly influenced by industrial, commercial, and agricultural development. Farmers have long since contributed a large share of water pollution, especially in the State of Washington. Increasingly, though, farmers are finding ways to save money and water quality at the same time. Soil conservation practices maintain soil fertility as well as protect water quality. Precise applications of fertilizer, irrigation water, and pesticides save money and reduce water contamination. Preserving wetlands that act as natural processing facilities for removing sediment and contaminants helps protect surface and groundwaters.

Due to increased urbanization, the Hylebos Watershed is experiencing a fluctuation in levels of pH, dissolved oxygen, nitrates, phosphorus, turbidity, and conductivity. Urban development, surrounding existing water systems, can cause many negative impacts such as, vegetation loss, increased runoff, and increases in water temperature. As a result, more problems arise such as bank erosion, less shade/canopy cover, decrease in organic and woody debris, poor water quality, and poor fish and wildlife habitat.

The Hylebos Watershed has a wide range of potential pollutants due to the extensive land uses within the watershed. The industrial and commercial areas potentially release grease and oils, asbestos from automobile brakes, solvents and metals. Further, the extensive area covered by asphalt, within this watershed, also contributes to oils, metals and asbestos. The residential areas potentially contribute phosphorous and nitrogen from fertilizer uses as well as fecal coliform bacteria from pet waste. The lack of a buffer zone allows cows direct access to the river and potentially contributes fecal coliform, ammonia, and possibly giradia and/or cryptosporidiun. While the city has some excellent systems in place, to reduce the impact of these pollutants, there is still issues surrounding turbidity, dissolved oxygen, and nitrates. Community education, consistent enforcement and continued continued fines for violaters may help bring the Hylebos closer to the standards for a healthy stream.

While most physical and nutrient parameters surveyed in the watershed do not indicate a significantly impaired state, the occurrence of high nitrate concentrations, high phosphate concentrations, high conductivity, high turbidities, and low dissolved oxygen at some of the sites sampled coupled with the general dominance of pollution-tolerant taxa and/or lack of pollution sensitive macro-invertebrates suggests that the Hylebos watershed may suffer from degraded water/habitat quality. While restoration efforts are beginning to be employed within the watershed, more significant efforts will need to be taken if this watershed is to be restored to a functional and self-sustaining watershed.

Our results for pH were in line with other sites sampled April 25, 2003. The average pH for the Hylebos on April 25, 2003 was 6.93, which is within the range for a healthy stream. However, the Kitts Corner outflow was below the minimum standard for a Class A stream (Kitts Corner measured 5.89 and the minimum is 6.5). The UWT 2002 data also included one site that was below the minimum for a class A stream. The 2002 data indicated the Seatac inflow only measured 5.93. The standards for dissolved oxygen Class A streams is greater than 8.0 mg/l. Three sites were below 8.0 in 2003 and one was in 2002. The turbidity measurements had a wide range for both 2003 and 2002. For 2003, the sites ranged from a low of 2 and high of 123.67. The 2003 measurements included five sites that were in excess of the Class A standards. All three measurements for 2002 were also above the Class A standards. Nitrates also reflected a wide variance in measurements from site to site. Nitrates ranged from .31 mg/l at 359th to 194 at Kitts Corner outflow. Three of the 2003 sites were above the class A standard of less than 10 mg/l. However, all four of the 2002 sites reported were within the healthy range. All of the temperature readings for 2002 and 2003 were well below the standard (18° C). The two biggest problems for the Hylebos appear to the turbidity level and the dissolved oxygen level. The nitrates are also a concern in certain areas. These issues would need to be addressed if the stream is to support healthy fish in the future.

Comparison to healthy stream standards
Site Name
 		pH D.O. (ml/L) Turbidity (NTU) Conductivity (range 0-200) Nitrates (mg/L) Phosphates (mg/L) Temp (Celsius)
1. SeaTac Mall Regional Pond
7.116
5.7
9.33
12.87
0.847
0.034
10
2. Kitts Corner Regional Pond Outlet
5.89
9.47
122.6
4.86
194.82
0.0349
11.5
3. Brook Lake Inflow
7.2
9.07
2
70.67
5.63
0.02
n/a
4. Brook Lake Outflow
6.98
5.97
5
145.89
10.07
0.01
n/a
5. 356th Regional Pond Inflow
7.09
7.1
115
77.37
0.78
0.11
10.3
6. 359th Street
6.97
10
15
140.83
0.31
0.04
13
7. 373rd Street
7.8
9.2
2.67
174.2
17.35
0.02
14
8. Fife Maintenance Station
6.46
8.3
123.67
739.87
8.39
0.0773
11
MEAN
6.93825
8.101
49.409
170.820
29.775
0.043
11.633
WA WQS June 1998 Class AA
6.5-8.56
>9.5 mg/L
<5 NTU
n/a
<10 mg/L
n/a
<16
WA WQS June 1998 Class A
6.5-8.56
>8.0 mg/L
<5 NTU
n/a
<10 mg/L
n/a
<18
WA WQS June 1998 Class B
6.5-8.56
>6.5 mg/L
<10NTU
n/a
<10 mg/L
n/a
<21
Safe Drinking Water Act
6.5-8.56
n/a
n/a
n/a
<1 mg/L
n/a
n/a
Kegley/Andrews Comments
n/a
8.32 mgL (pg.30)
n/a
30-400 mS/cm (pg.43)
Drinking water should be <10 mg/L (pg.74)
n/a
n/a



Introduction | Locations | History | Land Use | Methods | Results & Discussion | Work Cited
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