1. Lake Independence Phosphorus TMDL Critique Stephanie Koerner & Zach Tauer BBE 4535 Fall 2011

2. Watershed Description  Pioneer-Sarah Creek Watershed  851 – acre lake / 7631 – acre watershed  North Central Hardwood Forest ecoregion  Deep lake – max depth: 58ft  15 miles West of Minneapolis  Uses:  Recreation  Aesthetic viewing  Contains portion to Municipalities  Medina  Independence  Loretto

3. Watershed Shoreline  Receives 7,631 acres of runoff  Uses of shoreline:  Agriculture  Commercial  Park and Recreation  Residential  298 animal units are on the shoreline, mostly of Horses on Single Family Property.

4. History of Watershed  Prior to 1850 the surroundings were predominantly Forests and Wetlands.  July 4, 1854 settlers found the lake giving it’s name Lake Independence for the day it was found.  Area slowly developed with lakeshore homes and agriculture  Drainage systems were then put in place which drastically changed the hydrologic system  Recently seasonal lake homes on the lake were converted to year round homes

5. Water Quality  Monitored biweekly from 1990 except in 1992  Phosphorus and chlorophyll data show no significant trends of improving or declining since 1990 but Secchi disk data showed a reduction in clarity.

7. Water Quality – Aquatic Vegetation  Curlyleaf pondweed and Eurasian watermilfoil cause water clarity and recreational problems from the lake.  Curlyleaf pondweed grows under ice and forms dense growth by late spring and dies in mid July causing increase in nutrients.

8. 303(d) Listing  Total phosphorus concentration exceeded 40ppb 11 of 12 years from 1990 to 2003.  Calculated from a minimum of 9 samples a year  Placed on 303(d) list as impaired waterbody for its recreational uses in 2002.

9. Modeling  MINLEAP, BATHTUB and Canfield and Bachman models were.  MINLEAP quantified the feasibility of the target goal  Canfield and Bachman estimated TP reduction to achieve target  BATHTUB estimated nutrient flows from subwatersheds  Canfield and Bachman was used based on field monitoring and computer model which resulted in 2,381 lbs/yr assuming normal precipitation.  Model predicted reduction of 1300 lbs/yr to reach 36ppb.

10. MINLEAP  Calculated with “typical” nutrient inflows to unimpaired lakes in central Minnesota  Target concentration is likely attainable.

11. BATHTUB with GIS

12. GIS for Livestock Contribution

13. Bachman and Canfield  Sources of phosphorus

14. TMDL  TMDL = WLA + LA + MOS

15. TMDL Continued  Seasonal Variability  MOS – 35 lbs/yr was incorporated into TMDL for rainfall Variability

16. Final Phosphorus TMDL  Non-degradation Policy  Future land development requires to meet strict guidelines to protect water quality and prevent increases in runoff and nutrient loading.

17. Public Participation  Funding for the study was provided by the Three Rivers Park District and Lake independence Citizens Association provided many hours of volunteer work.  Efforts between the Three Rivers Park District, local municipalities, and MPCA the diagnostic feasibility evolved into the Lake Independence Phosphorus TMDL  Estimated associated costs, expected effectiveness, predicted longevity, and technical feasibility.  Target goal, WLA and LA were discussed by a large group of stakeholders.  Committee met monthly for two years  Decided WLA and LA would be based on source instead of municipal or subwatershed basis.

18. Implementation  Reducing movement of phosphorus into Lake Independence.  45% reduction (1081lbs/yr)  872 lbs/yr decrease from each identified external source  209 lbs/yr decrease of internal loading due to reduction of external sources.

19. Source Implementation Plan  Continue water quality monitoring program  Water sample collection  Inflow monitoring during and after implementation

20. Cost and Implementation  Ranked in highest priority, Time lines, Estimated costs, responsible parties and tasks are explained  Goal reduction and possible reduction  Agriculture – Buffer Strips  300 acres can be installed  $150,000 to $500,000  Goal reduction 284lbs possible reduction 288lbs  Animal Waste – BMPs  33 feedlots  $330,000 to $825,000  Goal reduction 378lbs possible reduction 435lbs  Urban Development – urban runoff  Goal reduction 146lbs possible reduction 202lbs  Failing Sewage Treatment – inspections  $500,000  Goose Removal – reduce goose population  $2,500  Loretto Wastewater Treatment

21. Example of Implementation Plan

22. Critique  Overall capable reduction  Effort and time put behind implementation plans  Local involvement was helpful  Useful and long record of data  Water Quality was not monitored for the year of 1992 but was not explained.  Sediment cores were used from four other lakes in the area of Lake Independence but not from the lake to estimate historical phosphorus loads.