Lake Assessment Program - Blue Lake, Hubbard County

Blue Lake is a moderate sized lake (324 acres) located in Hubbard County. Land use in the watershed is characterized by forest (48 percent) and urbanlresidential (17 percent). The high percentage of urban land use is a function of the lake's small watershed and highly developed shoreline. The lake is located near the transition of two ecoregions and as such, its land use is intermediate between the two regions (see Figure 1). Blue Lake was sampled during the summer of 1996 by Minnesota Pollution Control Agency (MPCA) staff and citizens from the Blue Lake Association (Association). Water quality data collected during the study reveal a summer mean phosphorus concentration of 13 pa, mean chlorophyll-a of 3 pg/L and Secchi transparency of 15.2 feet. The chlorophyll-a and Secchi values are well within the range of values exhibited by reference lakes in this ecoregion: The phosphorus value, however, is better than the typical range of values exhibited by reference lakes in the NLF ecoregion. Total phosphorus, chlorophyll-a and Secchi transparency help to characterize the trophic status of a lake. For Blue Lake, these measures indicate mesotrophic conditions.