Upper Pine Lake IA 02-IOW-760

Assessment Comments

Assessment is based on results of ISU lake surveys and surveys by IDNR Fisheries Bureau.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation uses) were "not assessed."  Continued to assess support of the Class B(LW) aquatic life uses as "partially supported."  Other beneficial uses remain "not assessed."  EXPLANATION:  The level of support of the Class A (primary contact recreation) uses remained "not assessed" due to (1) lack of swimming use at this lake (see assessment developed for the 1994 report ) and (2) the lack of information on levels of indicator bacteria at this lake.   The previous (1998) assessment of support of the Class B(LW) uses ("partially supported") was reviewed and approved by the DNR Fisheries Bureau in 2000.   The level of support of fish consumption uses was changed from "fully supported" to "not assessed" due to the lack of recent fish contaminant monitoring at this lake.  

Using the median values from the Iowa State University statewide surveys of Iowa lakes in 2000 and 2001 (approximately six samples), Carlson's trophic state indices for total phosphorus and chlorophyll-a at Upper Pine Lake are 69, 62, and 59, respectively.   According to Carlson (1977), the index value for total phosphorus places this lake in the upper range between eutrophic and hyper-eutrophic lakes; the index value for chlorophyll-a is in the lower range between eutrophic and hyper-eutrophic lakes, and the index value for secchi depth is in the upper range of eutrophic lakes.   These index values suggest excessive levels of phosphorus but less than expected production of suspended algae and better than expected water transparency.