11th International Drainage Symposium August 30-September 2, 2022 Des Moines, Iowa

1. Leading at the Edge:
Perspectives on Conservation
Drainage Ditches
&
Panel Discussion
Jessica D'Ambrosio
Ohio Agriculture Director, The Nature Conservancy
Jessica.dambrosio@tnc.org

2. In-field practices:
 Manage the SOURCE
of Nutrients
 Protect Soils
 Good for Production
 Introduce Biodiversity
 Sequester Soil Carbon
4R Nutrient Management
Cover Crops and Diverse Rotations
Reduced / No-till

3. The Challenges

4. Leading
Edge
at
the
Advancing
Edge
of
Field
Practices
nature.org/EdgeofField

5. Key Elements of the Edge of Field (EoF) Roadmap
Build the
economic
case
Increase
capacity to
implement
Elevate a
culture of
conservation

6. Practice
Body of
Literature
Effectiveness
(Median % Removal)
Estimated Annual Cost Effectiveness Co-benefits
Nitrate-
nitrogen
TP DRP S
ediment
Nitrogen
($/kg)
Phosphorus
($/kg)
Sediment
($/metric ton)
Vegetated buffer* Robust 84.5 78.0 87.5 $3.59-$4.211,2 $26.40-$30.901,2
Grassed waterway Limited - 11.0 - 87.0 - $562-$1,1243 $2.08-$1583
Prairie strip Growing 67.0 90.0 - 96.0 $1.59-$2.344 $6.97-$10.254 $7.79-$11.464
Wetland (Restored) Robust 39.0 41.0 27.0 $0.06-$14.545
Wetland (Constructed) Robust 44.0 44.0 62.0 50.6 $1.80-$4.406
Bioreactor Growing 39.8 ‫־‬ - ‫־‬ $1.10-$3.806 - -
Saturated buffer Growing 61.0 ‫־‬ ‫־‬ ‫־‬ $1.76-23.137 - -
Controlled drainage Robust 38.5 ‫־‬ ‫־‬ ‫־‬ $1.70-$4.506 - -
Two-stage ditch Limited 7.5 40 11 22 $4.61-$11.638 $1.59-$4703 $1.14-$1043
Phosphorus filter Limited - - 40.0 - - $110-$1,1029 -
Drainage water recycling Limited 34.4 24.0 18.0 -
Tailwater recovery system Limited 54.5 (TN) 45.5 45.0 66.5 $0.13-39610 $0.61-3,31610 <$1-$77010
Co-Benefits Key: Wildlife Pollinators Water storage Carbon storage Crop yield
(1) IEPA, IDOA, and IWRC2015; (2) IDALS
, IDNRand IS
U2013; (3) TetraTech Inc. 2019; (4) Tyndall et al. 2013; (5) Hansen et al. 2015; (6) L. Christianson et al. 2013; (7) Kult and
Klein 2018; (8) Roley et al. 2016; (9) National S
oil Erosion Research Laboratory 2017); (10) Omer et al. 2019
* Vegetated buffer valuesare for practicesimplemented on non-tile drained land.
EoF Build the Economic Case
For reference, the annual cost effectiveness of planting a cover crop was $11.46/kg nitrate. (Iowa Nutrient Reduction Strategy 2013.)

7. Tile Drainage Surface Runoff
Underground Outlet - 620
Wetland Restoration - 657
Woodchip Bioreactors - 605
Nutrient Removal Wetlands - 656, 658
Saturated Buffers - 604
Grassed Waterways - 412
Water and Sediment Control
Basins - 638
Riparian Buffers - 391, 580
Drainage Water Management - 554 Contour Buffer Strips - 338
ACPF
Toolbox
Agricultural Conservation Planning Framework
EoF: Increase capacity to implement
Coming soon: Two-stage Ditches - 582
Coming soon: Phosphorus Removal Structures -
782

8. Conservation Planning Scenario
– watershed and field scale
178 Denitrifying Bioreactors sites identified
9,125 acres potentially treated
46 acres used for sites
13 Nutrient Reduction Wetland sites identified
~4,500 acres potentially treated
~60 acres of Pool and ~100 acres of Buffer
~115 acre-feet of storage
279 Grassed Waterways sites identified
27.5 miles total
521 feet mean length
26 Drainage Water Mgmt sites identified
725 acres total
27.8 acres mean size
28 Miles of perennial streams evaluated
178 stream segments total
0.21% Mean ‘buffer-area ratio’
27,724-acre watershed, 1,193 fields evaluated

9. ArcOnline
Viewer

11. PANEL DISCUSSION AND QUESTIONS
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