Nutrient Management and Edge of Field Monitoring Conference December 1-3, 2015 Memphis, TN

1. Prioritizing watersheds for BMP
placement: southern Minnesota
case study
Lori Krider, PhD. Candidate
Dr. Bruce Wilson, Professor
Department of Bioproducts and Biosystems Engineering
University of Minnesota

2.  Water quality issues
 Agriculture and drainage
 Watershed approach
 Case study
 Mullenbach Two‐Stage Ditch
 Stability and nitrates
Overview

3.  Restoration vs. Protection
Basin Overview
stormwater.pca.state.mn.us

4.  Minnesota River: CAFOs, fertilizer pollution,
row crops, erosion
 Nitrates and sediment
Water Quality Issues in S MNEPA SPARROW, 2013 (mrbdc.mnsu.edu)
19.9 mil lbs/yr
18.2 mil lbs/yr
10.1 mil lbs/yr
(Mattteson &
Baskfield, ND)
startribune.com
WHY?
‐climate change
‐river bluffs
‐agricultural practices
Minnesota River
Mississippi River

5. fws.gov
Types of Drainage Systems
Surface Drainage:
Ditches ‐ remove standing
water (outlet for tiles)
Subsurface Drainage:
“Tiles” ‐ remove water from soil

6. Why Drainage?
• Decreased maintenance of transportation
• Increased crop yields
• Increased land value
• Reduced risk of malaria
Illinois had settlements abandoned
because of malaria in 1830s
Fort Snelling: 66 cases per 1000 people
per year (1829‐1838)
Palmer (1915):

7. Ditch Construction:
Blue Earth, Brown, Le Sueur, & Nicollet County
0.00% 5.00% 10.00% 15.00% 20.00% 25.00% 30.00%
Prior to 1880
1900-1909
1920-1929
1940-1949
1960-1969
Quade et al., 1980
Above average precipitation ‐> greater ditch construction
Drought
First
Second

8. Changes in Row Crop Acreages
AcreageofCrops(inthousands)
Year
1870 1890 1910 1930 1950 1970 1990 2010
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
Corn
Soybeans
Data Provided by Steven Taff
Increasing commodity prices and growing populations
100% yield increase

9. MN AES
MN AES
Fertility
Manure Application Rates:
1930’s: 8 tons/ac, 1950’s: 6.2 tons/ac, 1970’s: 4 tons/ac
(V. Cardwell)
More row crops ‐> less livestock
David Hansen
Constituents known and constant
Commercial Fertilizers:
1950’s: 14%, 1960’s: 67% and 1979: 95%
(V. Cardwell)
Year
1950 1970 1990 2010
NApplicationRates(lb/ac)
0
20
40
60
80
100
120
140
160
Decrease in row spacing

10.  Minnesota Pollution Control Agency (MPCA)
 Intensive Watershed Monitoring
Watershed Approachmpca.state.mn.us
Watershed Restoration and Protection Strategy (WRAPS)

11.  Minnesota Pollution Control Agency
 Intensive Watershed Monitoring & WRAPS
 Board of Water and Soil Resources (BWSR)
 Targeted Watersheds: grants to local governments
 1 Watershed, 1 Plan: integration
Watershed Approach
bwsr.state.mn.us

12. BMP Placement
Tomer, 2013
Tomer, 2013

13.  MPCA Sediment Reduction Strategy (Jan 2015)
 Minnesota and Lower Mississippi River
 50 percent reduction by 2030
 90 percent reduction by 2040
Sediment Management
mpca.state.mn.us

14.  MPCA Nutrient Reduction Strategy (Sept 2014)
 Mississippi River
Nutrient Management
pca.state.mn.us
Part of the solution
is agricultural BMPs
‐bioreactors
‐two‐stage ditches
‐WASCOBs
‐cover crops, etc . . .

15.  Cedar River Watershed
Case Study
75% row crops

16.  Mullenbach Two‐Stage Ditch
 Constructed Oct 2009
Kramer, 2011
Mower County
Case Study
Kramer, 2011
Funding: MPCA
Data: 2009 ‐ 2013

17. Two-Stage Design
bayjournal.com
* Bank sloughing
* Reduced sediment transport
* Limited water treatment
Conventional:
* Steady, uniform flow
* Larger wetted perimeter, surface area
* Smaller average bed shear
Two‐Stage Designs:

18. Natural Processes
Stage 1: Low Flow Channel
Stage 2: High Flow Channel

19.  Stability
Analyses

20. Cross-Sectional Profiles
92
94
96
98
100
102
104
106
108
110
112
0 10 20 30 40 50 60 70 80 90
Elevation (ft)
Distance from east stake (ft)
Location
40+04
Pre‐Construction
Apr‐09Oct‐10
Apr‐12
Nov‐13

21. Cross-Sectional Surveys
0
2
4
6
8
10
12
14
300 600 900 1200 1800 2100 2400 2700 3000 3300 3600 4200 4500 4800 5100 5400 5700 6000
Channel Width (ft)
Station (ft)
Bankfull Width Increased by ~11% ‐ less active sediment supply

22. 90
92
94
96
98
100
102
104
106
108
0 1000 2000 3000 4000 5000 6000
Elevation(ft)
Channel Distance (ft)
bed riffle pool
90
92
94
96
98
100
102
104
0 1000 2000 3000 4000 5000 6000
Elevation(ft)
Channel Distance (ft)
Pool BedRiffle
Thalweg Longitudinal Profile
Pre‐Construction:
* 5 pool‐riffles
November, 2013:
* 65 pool‐riffles
sorting larger particles
cleaning out finer particles
October, 2010:
* 0.5 ft aggradation
* More pool‐riffles

23. From Brenda DeZiel
Fish Community
Low DO Need sand/gravel Degradation
FIBI: 44 ‐> 52.5 (+8.5)
574 ‐> 1050 individuals

24.  Daily nitrate and precipitation: April 27 – Oct 10, 2010
Nitrate Concentration
ΔC~ 4 mg/L

25. Nitrate Removal (denitrification)
• Mass balance (in‐stream)
• N2O laboratory
– Acetylene inhibition assay
– Sediment
Approaches:

26. Mass Balance Method
Upstream
Qin
[N]in
[δ18O]in
Downstream
Qout
[N]out
[δ18O]out
Groundwater
Qgw
[N]gw
[δ18O]gw
Nremoved
Tiles
Qtile
[N]tile
[δ18O]tile

27.  August 3, 2010 – entire ditch length
 Groundwater δ18O and NO3 unknown
0
5
10
15
20
25
30
35
40
45
15 20 25 30 35 40
Percent Removal of N
Groundwater NO3‐N Concentrations
Large Groundwater Contribution
(δ18O= ‐9)
Modest Groundwater Contribution
(δ18O= ‐10)
Mass Balance Results

28. Mass Balance Results
(September 18, 2013, 51+00 to 53+73, ΔQ=0.13 cfs, Qus = 1 cfs)
Single groundwater source: 14.6% (6.5 kg N/day)
Two groundwater sources: 16% (7.23 kg N/day)
0
20
40
60
80
100
120
140Nitrate‐N (mg/L)
September 18
September 20
1 source?
2nd source?September 21, 2011
* Entire ditch length
* 8.78 kg N per day
* 34%

29. Acetylene Inhibition
Nitrification
NH3
+
NO2
‐
NO3
‐
Denitrification
NO2
‐ NO N2O N2
Acetylene Method
(laboratory)
In‐situ Method
* Lab measurement of N2O

30. Laboratory Results
0
20
40
60
80
Benches East Riparian West Riparian Channel
Denitrification Rates
(mg N2O‐N m‐2h‐1)
South
North
Removal Rate
* Entire Ditch
* 8.84 kg N/ day

31. Linear Wetland Nitrate Removal
Enhanced Ditch Nitrogen Removal
200 ft
0
5
10
15
20
25
30
35
Nitrate‐N (mg/L)
In (28+00 tile) Out (30+00)
Reduced by ~ 1 ‐ 2 mg/L
(5 – 10%)

32. • Two‐stage ditch is stable
• In‐stream habitat improvement
• Shows potential for substantial biotic
function
• Nitrate removal between 10% and 30%
Summary

33. Questions and Comments