Chemical Monitoring
Sunrise River
| Monitoring Location | at Highway 77, Linwood Township STORET SiteID = SunriseRiver_Hwy77 |
| Monitored By | ACD Staff |
| Years Monitored | 2001, 2003 and 2006 |
| Background: This monitoring station is the bottom of the Sunrise River's watershed in Anoka County. This segment of the Sunrise River orginates from the Martin Lake's outlet structure about 3 miles upstream from the monitoring site. Typical stream flows at baseflow are about 12 cfs and can reach >40 cfs during spring runoff. | |
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| Results and Discussion Eight water quality samples were taken in 2006, including four during storm events and four during baseflow (see figures and table below). Overall, water quality was slightly poorer than average, though this average was driven by overall poor water quality on May 30 and higher nutrient levels in late summer which were likely due to seasonal changes in Martin Lake upstream. May 30, 2006 had much poorer water quality than any other date. In fact, it had the highest turbidity and total suspended solids, and second lowest dissolved oxygen and total phosphorus observed during any of 24 observations over three years. Interestingly, these same parameters were similarly poor on nearby Data Creek and Cedar Creek, and to a lesser degree on Coon Creek. This suggests the poor water quality on May 30th was climate-driven. May 30 was not a storm event. Rather, water levels were dropping from springtime highs. All of the streams where the poor water quality was observed flow through extensive wetlands, especially those that had the poorest conditions. It is plausible that the high turbidity and nutrients were caused by drying and sloughing of wetland peat soils into the stream. This input of organic matter would have increased levels of decomposition, causing dissolved oxygen to fall. Aside from May 30th, the next highest total phosphorus and turbidity readings were three measurements in August. August is the time when phosphorus and algae typically rise to their highest levels in upstream Martin and Typo Lakes. The high readings in the Sunrise River were probably a reflection of the condition of those lakes. Conditions may have been exacerbated further by storm conditions during two of these three samples. At all other times of 2006 phosphorus was lower than the median for streams in Anoka County, and would be considered good. Observed chlorides, conductivity, and salinity suggest that the source of some dissolved pollutants to the Sunrise River is the shallow groundwater. All three of these were highest during baseflow conditions, when the stream is fed primarily by shallow groundwater. Storms seemed to dilute them. Studies elsewhere in Anoka County have found that a primary source of high conductivity, chlorides, and salinity during baseflow is road deicing salts that have infiltrated into the shallow water table. The levels observed in the Sunrise River were not high enough to impact stream life. |
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