Minnesota Integrated Watershed Study DNR Case Study
Study Highlights
•Paired Watershed Study Cty Ditch 29 - Impaired Cty Ditch 27 - Impaired Huse Creek – Unimpaired •Study Focus (Water Quality) Wetland loss and restoration Drained Depressional Lakes Impacts of Drainage Density and Improvements Impacts of Pattern Tile on flow & WQ
JD 29 (2010 Aerial Photo)
JD 29 GSSHA Grid
JD 27 (2010 Aerial Photo)
JD 27 GSSHA Grid
Shakopee Creek Study Goals
• Quantify hydrologic changes in watersheds (1950 to present) • Identify sources of impairments • Demonstrate benefits of installed BMPs • Apply Suite of BMPs to Mitigate Impairments • Quantify Effectiveness of “Targeted” BMPs • Inform Strategy to Clean-Up Lakes
BMPs
Minnesota River Basin
A History of Change
•Critical Economic Driver in Our Economy
•History of Drainage for Ag Productivity
•Cumulative Effect of These Changes Has Altered Hydrologic Balance
•Increased Nutrient and Sediment
•What Can We DO to Improve Water Quality While Minimizing Impact on Ag Production
Shakopee Creek, Chippewa River Basin
County Ditch 27 GSSHA Grid Draped Over Lidar Hillshade
Grid Cell Size: 30 meter (0.22 acres)
Drained Shallow Lakebeds
Circa 1938
Circa 1991
Depressional Lakes and Wetlands Drained for
Ag Production
Shakopee Creek Judicial Ditch 27 Drainage History
1991 Photo
2010 Photo
Wetland Restoration JD 29 North Branch
June 1997 Event Current Conditions Pre 1950 Conditions
Olson Wetland 2006
With Olson Wetland W/O Olson Wetland
1955 Photo
2010 Photo
Drainage Density/Improvements
Repair or Improvement?
Ditch side slopes 1:1.5
Ditch Side Slopes 1:2
Study Goals
Quantify Impacts of Drainage on Discharge, Sediment and Nutrient Delivery to D/S Chain of Lakes
Evaluate Benefits of Wetland and Shallow Lake Restorations on WQ
Evaluate Impacts of Climate on Hydrologic Response in a Changing Landscape
Explore a Suite of Ag BMPs to Mitigate Impacts of Hydrologic Alterations Related to Ag Production
Study Schedule
Task Completion Date
Finalize Model Geometry Oct-Nov 2013
Calibrate Models Nov - Dec 2013
Add Sediment Simulation Dec 2013
Run Model Scenarios Dec 2013
Summarize BMP Effectiveness (Sediment and Flow)
Apr 2013
Look at Nutrient Links ??????
Inform DSS 2014-15
Model Lake Nutrient Loads (Not Part of Scope)
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