Biological Monitoring
Hardwood Creek
| Monitored By | Forest Lake Area Learning Center |
| Number of Years Monitored | 5 yrs |
| Background: Hardwood Creek originates in Washington County and flows east to Rice Creek and the Rice Creek Chain of Lakes. The surrounding landuse is primarily agricultural, with some residential areas. The creek meanders substantially through the landscape, unlike many other streams in the county, which have been channelized. The stream bottom is sand, gravel, and some cobble. The banks are slightly eroded and the canopy cover is good. This is a small stream with a width at baseflow of approximately 10-15 feet and depth of approximately 6-12 inches. Sampling is conducted on the north side of the road on private property, with permission. | |
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| Results Forest Lake Area Learning Center classes monitored Hardwood Creek at Highway 140 in both spring and fall 2006, facilitated by the Anoka Conservation District. Biological data from this stream has had a lot of year to year and seasonal variation, sometime indicating ok stream health and other times indicating very poor health. 2006 is a good example of this variation. In spring only six families were found, and 87% of those were from only two pollution-tolerant families. Invertebrates were difficult to catch because of low abundance. The stream smelled like manure. In contrast, in the fall the number of families more than doubled to 15. Stream habitat improvements and erosion repairs completed by the Rice Creek Watershed District in 2006 may have played a role in these improvements, though fall results have been better than spring for the last several years. |
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| Discussion Hardwood Creek is on the Minnesota Pollution Control Agency’s 303(d) list of impaired waters for impaired biota and dissolved oxygen. The Rice Creek Watershed District is coordinating a TMDL investigative study. Our biological monitoring does indicates a below-average biological community, but lends only modest insight into what might be causing this impairment. Intermittent water quality degradation, such as low dissolved oxygen, is probably partially responsible. The water’s strong manure smell in spring 2006 is also concerning. Habitat degradation is also probably partially responsible, though habitat improvements done at the sampling site in 2006 should have a positive effect. The improvements seen in fall over the spring of 2006 are not likely due to habitat improvements alone. Differences between spring and fall have been notable for several years. In 2004, 2005, and 2006 the spring invertebrate indices of stream health were much poorer than the fall indices. This is not typical of other similar nearby streams, suggesting climatological factors are not the cause. |
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