Lake Assessment Program - Lake Frances and Lake Tustin, LeSueur County

Document
Description
Lakes Frances and Tustin are located in southern LeSueur County in south central Minnesota. Lake Frances has a surface area of 800 acres, a mean depth of 13 feet, and a maximum depth of 60 feet. Lake Tustin has a surface area of 65 acres, a mean depth of about 3 feet, and a maximum depth of 5 feet. The watershed area of Lake Frances (including 135-acre Round Lake to the west) is approximately 3050 acres. The Lake Frances watershed, plus an additional 680 acres (including 145 acre Rays Lake) drains to Lake Tustin. Lake Tustin drains to Lake Tetonka of the Cannon River system. Water quality data collected on Lake Frances during 1998 reveal a summer-mean total phosphorus (TP) concentration of 34 μg/L, a mean chlorophyll-a concentration of 19 μg/L, and a Secchi transparency of 4.3 feet (1.3 m). The TP and chlorophyll-a are within the range of values exhibited by reference lakes in the North Central Hardwood Forest Ecoregion. The Secchi transparency, however, is slightly less than the range for reference lakes. For Lake Tustin, the TP and chlorophyll-a values are much higher, and the Secchi transparency much less, than for the reference lakes (372 μg/L, 147 μg/L, and 1.4 feet, respectively). Total phosphorus, chlorophyll-a and Secchi transparency help to characterize the trophic status of a lake. For Lake Frances, these measures indicate eutrophic conditions; while Lake Tustin would be considered hypereutrophic. Lakes Frances and Tustin were also monitored by MPCA staff in the summer of 1996, and Lake Frances through the Citizen Lake-Monitoring Program (CLMP) since 1992. The Lake Frances CLMP data shows no statistically significant change in Secchi transparency since 1992.
Date Issued
2002
Number of Pages
38
Decade
Rights Holder
Minnesota Water Research Digital Library
Rights Management
Public Domain