This document discusses a project to improve water quality in Fox Lake, Wisconsin through the use of enhanced ditch plugs and riparian wetlands. The project, on Alto Creek, included mapping the watershed, modeling hydrology and hydraulics, and selecting sites for low-head control structures to inundate existing wetlands during storms. Water quality monitoring showed reductions in nutrients like phosphorus. The goal was to reduce sediment and nutrient loading to Fox Lake in a reasonable, low-cost manner.

1. Hey and Associates, Inc.
Use of Enhanced Ditch Plugs and
Riparian Wetlands to Reduce Nitrogen
and Phosphorus Export from Small
Agricultural Watersheds
Neal O’Reilly, Ph.D., PH
Conservation and Environmental Studies
University of Wisconsin - Milwaukee

2. Hey and Associates, Inc.
Partners
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3. Hey and Associates, Inc.
“A Lake is A Reflection of its Watershed”
Source: Primary Components of a Watershed
(Heathcote, 1998). Conservation and Environmental StudiesUWM- Conservation and Environmental Studies

4. Hey and Associates, Inc.
“A Lake is A Reflection of its Watershed
and Characteristics of its Floodplains and
Riparian Wetlands”
O’Reilly’s Corollary Conservation and Environmental StudiesUWM- Conservation and Environmental Studies

5. Hey and Associates, Inc.
Water Quality Benefits of Floodplains
• Copper, J. R, J. W. Gilliam, R.
B. Daniels, and W. P. Robarge.
(1987). Riparian areas as
filters for agricultural
sediment. Soil Science Society
of America Journal. 51:416‐
420.
• Copper, J. R. and J. W.
Gilliam. (1987). Phosphorus
redistribution from cultivated
fields into riparian areas. Soil
Science Society of America
Journal. 51:1600‐1604.
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6. Hey and Associates, Inc.
Water Quality Benefits of Floodplains
• Cooper et al (1987)
monitored two small
watersheds to determine the
sediment and nutrient
removal efficiencies of
stream buffers.
• Copper found that stream
buffers can reduce sediment
delivery from cultivated
fields between 84% and 90%
and phosphorus by 50%
(Copper et al, 1987, and
Copper and Gilliam, 1987).
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7. Hey and Associates, Inc.
Water Quality Benefits of Floodplains
• Wetland Treatment for Water Quality
Wetland
Type
Suspended
Solids
Total
Phosphorus
NH3 Lead Zinc
Constructed 80 58 44 83 42
Natural 76 5 25 69 62
Source: (Strecker et. al. 1992)
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8. Hey and Associates, Inc.
Water Quality Benefits of Floodplains
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9. Hey and Associates, Inc.
Water Quality Benefits of Floodplains
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10. Hey and Associates, Inc.
Water Quality Benefits of Floodplains
• As we have developed
the landscape into
agriculture and urban
areas we have not only
modified the land use
but also the drainage
system and floodplains
through ditching and
tiling.
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11. Hey and Associates, Inc.
Water Quality Benefits of Floodplains
• In many watersheds
most small storms
do not even over top
the banks of the
stream and have
limited contact with
riparian vegetation.
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12. Hey and Associates, Inc.
Typical Stream Floodplain
Source: NRCS
1.7 to 2.0 year Storm
2 to 10 year Storm
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13. Hey and Associates, Inc.
Fox Lake, Wisconsin
• Fox Lake Inland Lake
Protection and
Rehabilitation District
• Wisconsin Department
of Natural Resources
Fox Lake
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14. Hey and Associates, Inc.
Fox Lake, Wisconsin
Surface area = 2,525 ac Conservation and Environmental StudiesUWM- Conservation and Environmental Studies

15. Hey and Associates, Inc.
Fox Lake, Wisconsin
• In the 1950’s mean total
phosphorus levels in
Fox Lake were less than
50 ug/l.
• Today total phosphorus
ranges from 150 to 400
ug/l
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16. Hey and Associates, Inc.
Fox Lake, Wisconsin
90% of Drainage Area
is in agricultural
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17. Hey and Associates, Inc.
Elements of the Fox Lake Restoration Plan
1. Shoreline
Stabilization
2. Watershed Protection
3. Aquatic Plant
Management
4. Fishery Management
5. Dam Replacement
6. Public Education
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18. Hey and Associates, Inc.
Fox Lake Watersheds
Total Watershed = 35,574 ac
Watershed to Lake Ratio 14:1
3,894 ac
13,693 ac
14,900 ac
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19. Hey and Associates, Inc.
Sediment and Phosphorus Inputs to
Fox Lake
Sub-watershed
Land Area
(ac)
Sediment
Load
(tons/yr)
Phosphorus
Load
(lbs/yr)
% total
Phosphorus
Load
% of Total
Load Due to
Cropland
Alto Creek 13,693 6,477 23,859 45% 98
Cambra Creek 14,900 4,156 18,530 35% 96
Drew Creek 3,894 1,861 6,834 13% 96
Fox Lake 3,087 1,000 3,845 7% 97
Total 35,573 13,494 53,068 100%
Sub-watershed
Land Area
(ac)
Sediment
Load
(tons/yr)
Phosphorus
Load
(lbs/yr)
% total
Phosphorus
Load
% of Total
Load Due to
Cropland
Alto Creek 13,693 6,477 23,859 45% 98
Cambra Creek 14,900 4,156 18,530 35% 96
Drew Creek 3,894 1,861 6,834 13% 96
Fox Lake 3,087 1,000 3,845 7% 97
Total 35,573 13,494 53,068 100%
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Based on WinHUSLE Modeling

20. Hey and Associates, Inc.
Strategy to Reduce Sediment and
Phosphorus Inputs to Fox Lake
• Conservation practices on
agricultural fields and
barnyard management
systems
• Buffers and grass waterways
on tributary drainage
channels
• Improved water filtering
through riparian wetlands
on main channels
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21. Hey and Associates, Inc.
Alto Creek Wetland Project
Purpose: To reduce
sediment and nutrient
loadings to Fox Lake
during moderate storms.
Approach: Series of low‐
head control structures
to cause moderate storm
events to spill over into
existing riparian
wetlands to filter
nutrients.
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22. Hey and Associates, Inc.
Alto Creek Wetland Project
Date
TSS
(mg/l)
TP
(mg/l)
SRP
(mg/l)
TKN
(mg/l)
NO2/ NO3
(mg/l)
5/18/2006 19 0.192 0.131 1.45 7.47
5/25/2006 66 0.061 0.035 0.92 8.42
5/31/2006 34 0.157 0.083 1.58 5.96
6/13/2006 20 0.084 0.042 0.54 10.8
6/19/2006 19 0.092 0.045 0.71 11.5
12/8/2009 10 0.050 0.022 0.4 11.2
5/5/2010 12 0.078 0.051 0.91 7.88
8/2/2010 20 0.237 0.217 1.16 7.29
8/22/2010 14 0.149 0.107 0.62 9.56
Mean 23.78 0.122 0.081 0.92 8.90
St. Dev. 17.27 0.06 0.06 0.41 1.96
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SRP = 66% of Total P
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23. Hey and Associates, Inc.
Alto Creek Wetland Project
Design Criteria:
• Reasonable access
• Low maintenance
• Low cost
• Potentially constructable by untrained labor, such as
“Secured Work Force”
• Does not impact on regulatory flood elevations
• Does not cause prolonged flooding of adjacent crops
• Allows fish passage
• Requires minimal wetland disturbance
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24. Hey and Associates, Inc.
Alto Creek Wetland Project
• The process was
started with detailed
mapping of the
watershed.
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25. Hey and Associates, Inc.
Alto Creek Wetland Project
• A 1‐foot contour map
was created from a
aerial fly over.
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26. Hey and Associates, Inc.
Alto Creek Wetland Project
• Selection of potential
restoration sites based
on topography and
potential for
maximizing the spread
of storm water into
the floodplain
wetlands.
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27. Hey and Associates, Inc.
Mapping of Soils and Land Use in GIS
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28. Hey and Associates, Inc.
Alto Creek Land Use and Soils
Land use Soil group Area(acres)
Water B 32.1
Water D 139
Commercial B 1.7
Agriculture A 9.6
Agriculture B 4322.5
Agriculture C 8.1
Agriculture D 890.6
HD‐Residential B 110.1
HD‐Residential D 14.8
LD‐Residential B 173.3
LD‐Residential D 37.5
Grass/Pasture B 1056.9
Grass/Pasture D 58
Forest B 52.1
Forest D 17
Total Area 6923.3
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29. Hey and Associates, Inc.
Runoff Curve Numbers
Water B 98
Water D 98
Commercial B 96
Agriculture A 67
Agriculture B 76
Agriculture C 83
Agriculture D 86
HD‐Residential B 87
HD‐Residential D 93
LD‐Residential A 54
LD‐Residential B 70
LD‐Residential D 85
Grass/Pasture B 68
Grass/Pasture C 78
Grass/Pasture D 83
Forest B 61
Forest D 80
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30. Hey and Associates, Inc.
Alto Creek Wetland Project
• Developed a
hydrology model using
HEC‐HMS.
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31. Hey and Associates, Inc.
Alto Creek Wetland Project
Water Level Control Structure
HEC-RAS
Cross-sections
• Developed a
hydraulics model
using HEC‐RAS to
understand the
potential areas of
inundation and impact
on regulatory
floodplains.
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32. Hey and Associates, Inc.
Alto Creek Wetland Project
• Selection of design storms.
~ 5 year 24-hr Storm Conservation and Environmental StudiesUWM- Conservation and Environmental Studies
Accumulative. Total P Load (%)

33. Hey and Associates, Inc.
Alto Creek Wetland Project
• Ecological assessment of each potential site.
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34. Hey and Associates, Inc.
Alto Creek Wetland Project
Reed Carney Grass
Cattails
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35. Hey and Associates, Inc.
Alto Creek Wetland Project
CTH F
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36. Hey and Associates, Inc.
Water Resources, Wetlands and EcologyWater Resources, Wetlands and Ecology
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Plan View
Cross-Section
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37. Hey and Associates, Inc.
Alto Creek Wetland Project
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38. Hey and Associates, Inc.
Alto Creek Wetland Project
Drawdown
notch and fish
passageway
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39. Hey and Associates, Inc.
Alto Creek Wetland Project
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40. Hey and Associates, Inc.
Alto Creek Wetland Project
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41. Hey and Associates, Inc.
Alto Creek Wetland Project
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42. Hey and Associates, Inc.
Alto Creek Wetland Project
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43. Hey and Associates, Inc.
Alto Creek Wetland Project
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44. Hey and Associates, Inc.
Alto Creek Wetland Project
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45. Hey and Associates, Inc.
Alto Creek Wetland Project
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46. Hey and Associates, Inc.
Alto Creek Wetland Project
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47. Hey and Associates, Inc.
Stream Flow
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48. Hey and Associates, Inc.
Area of Groundwater Discharge
Weir Structure
(AC‐1)
Upstream Sample Site
(AC‐2)
Groundwater
Discharge Area
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49. Hey and Associates, Inc.Conservation and Environmental Studies
Groundwater
Discharge Area
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50. Hey and Associates, Inc.
Total Suspended Solids (TSS)
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51. Hey and Associates, Inc.
Total Suspended Solids (TSS)
61.1%
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52. Hey and Associates, Inc.
Total Kjeldahl Nitrogen (TKN)
76.8%
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53. Hey and Associates, Inc.
NO2/NO3
35.9%
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54. Hey and Associates, Inc.
Total Phosphorus
61.1%
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55. Hey and Associates, Inc.
Dissolved Phosphorus
65.5%
67% of the total phosphorus is in the form of
soluble reactive phosphorus

56. Hey and Associates, Inc.
Total Phosphorus
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57. Hey and Associates, Inc.
Dissolved Phosphorus
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58. Hey and Associates, Inc.
Total Kjeldahl Nitrogen (TKN)
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59. Hey and Associates, Inc.
Nitrite/Nitrate
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60. Hey and Associates, Inc.
Alto Creek Wetland Project
• Conclusions:
– Use of low‐head dams
can be used to enhance
the connectivity of
stream flow with
riparian floodplain
wetlands.
– Increasing this
connectivity can improve
the trapping of sediment
and nutrients.
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61. Hey and Associates, Inc.
Alto Creek Wetland Project
• Conclusions:
– Because Alto Creek
carry's little suspended
sediment and most of
the Total Phosphorus is
in the dissolved form, I
believe here biological
uptake is a more
important factor for
nutrient removal than
sedimentation.
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62. Hey and Associates, Inc.
Questions
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