Post on 14-Aug-2020
Science Meets Policy:
A Case Study from a Regulated
Watershed,
Jordan Lake, North Carolina
Deanna Osmond, Dan Line, and Caela O’Connell NC State University
Dana Hoag, Mazdak Arabi, Ali Tasdighi, and Marzieh Mottalebi Colorado State University
LuWQ2015
LAND USE AND WATER QUALITY:
Agricultural Production and the Environment
Vienna, Austria, 21-24 September 2015
North Carolina River Basins and Land Use (2011)
Greensboro
Chapel Hill
Durham
Burlington
Jordan Lake
Reidsville
Map Produced: R. Austin, D.Osmond
Jordan Lake Watershed
0 10 205 Miles
North Carolina State UniversityDepartment of Soil Science North Carolina Stateplane, Zone 4901, NAD83 meters
2001 Land Use Land Cover
Landcover ClassCultivated
Forest
Pasture
water
Wetland
Developed
Jordan Lake Water Quality: The Problem
0
20
40
60
80
100
120
140
160
180
200
Dec
ember
6, 1999
Apri
l 19,
2001
Sep
tem
ber
1, 2002
Januar
y 1
4, 2004
May
28, 2005
Oct
ober
10, 2006
Feb
ruar
y 2
2, 2008
July
6, 2009
Novem
ber
18, 2010
Apri
l 1,
2012
Nutrient Load Reductions required by state of North Carolina from the 1997-2001 baseline period • Upper New Hope Sub
Basin: 35% N & 5% P • Lower New Hope Sub
Basin: 0% N & 0% P
• Haw Sub Basin: 8% N & 5% P
Jordan Lake Regulations: The Solution
Trading: urban development reduces
nutrients by trading with agriculture
Nutrient Reductions Required By All Sources
The goal of Analysis of Conservation Practice
Effectiveness and Producer Adoption Behavior in
the Jordan Lake Watershed (North Carolina) is to
add to the conservation effects knowledge base of
watershed-scale impacts of conservation practices
on water resources and producer behavior.
Project Research Objectives
Model water quality to
assess benefits from
historical implementation
and projected
implementation of
conservation practices, as
well as potential trades.
Determine conservation
practice effectiveness
(reduction of sediment, N
and P) at the watershed scale.
Determine optimal water
quality trading strategies
allowed by the Jordan
Lake Rule.
Determine and compare
motivators and deterrents
for conservation practice
adoption within the
watershed.
Determine
source
contributions
Project Research Results
Determine
source
contributions
Watershed Data
Total Nitrogen (TN) Source Losses
YEAR 2001 Dry Year
Adj R² = 0.94
Year 2003 Wet Year
Adj R² = 0.71
0
10
20
30
40
50
60
70
0 25 50 75 100
TN L
oad
(kg
/ha/
yr)
Urban Land Area/Total Watershed Area (%)
YEAR 2001 Dry Year
Adj R² = 0.79
Year 2003 Wet Year
Adj R² = 0.75
0
10
20
30
40
50
60
70
0 25 50TN
Lo
ad (
kg/h
a/yr
)
Ag Land Area/Total Watershed Area (%)
Project Research Results
Determine conservation
practice effectiveness
(reduction of sediment, N
and P) at the watershed scale.
Determine
source
contributions
Conservation Practice Effectiveness • Two paired watersheds monitored 8 years (pasture) and 6 years
(cropland)
• Treatment sub-watersheds based on farmer cooperation
• Pasture conservation practices: exclusion fencing and nutrient management
• Cropland conservation practice: N management (corn only in a 3 crop, 2 year rotation of corn, wheat, and soybean)
Pasture (C) Pasture (T)
Control and Treatment Pastures
Crop (T) Crop (C)
Control and Treatment Croplands
Pasture Pair Crop Pair
Conservation Practice Effectiveness: Pasture Nutrient and Sediment Reduction
Constituent Average Nutrient Load Both
Watersheds (kg/ha/yr)
Reduction Due to Exclusion Fencing
(%)
TKN 5.3 48
NOx-N 1.2 41
NH4-N 1.3 64
TP 3.0 61
TSS 333 73
Project Research Results
Model water quality to
assess benefits from
historical implementation
and projected
implementation of
conservation practices, as
well as potential trades.
Determine conservation
practice effectiveness
(reduction of sediment, N
and P) at the watershed scale.
Determine
source
contributions
SWAT Nutrient Delivery to Jordan Lake: Agricultural Baseline vs Current Climate
With and Without Riparian Buffers
Constituent Total Load
(kg)
Constituent Load per
Acre (kg/ha)
Baseline
(1997-2001)
Current
Climate
NO
Riparian
Buffers
Current
Climate
With
Riparian
Buffers
Total TN Load (kg) 16,612 26,716 17,420
Total TP load (kg) 10,589 18,361 8,603
Average TN (kg/ha) 0.92 1.48 0.96
Average TP (kg/ha) 0.59 1.02 0.47
Project Research Results
Model water quality to
assess benefits from
historical implementation
and projected
implementation of
conservation practices, as
well as potential trades.
Determine conservation
practice effectiveness
(reduction of sediment, N
and P) at the watershed scale.
Determine optimal water
quality trading strategies
allowed by the Jordan
Lake Rule.
Determine
source
contributions
Marginal Cost of Riparian Buffer Installation Relative to Total Nitrogen Reduced
0
20000
40000
60000
80000
100000
120000
140000
MC
($)
Reduction (kg/yr)
Supply (B-->R)
Reduction (kg TN)
# fields
Marginal Costs ($/kg TN)
0.5 1 310
4.5 ---- ----
45.0 10 654
450 65 2,022
3,281 1,227 17,833,668 2,722 kg TN max
0.00 454 907 1361 1814 2268 2721 3175 3629
Project Research Results
Model water quality to
assess benefits from
historical implementation
and projected
implementation of
conservation practices, as
well as potential trades.
Determine conservation
practice effectiveness
(reduction of sediment, N
and P) at the watershed scale.
Determine optimal water
quality trading strategies
allowed by the Jordan
Lake Rule.
Determine and compare
motivators and deterrents
for conservation practice
adoption within the
watershed.
Determine
source
contributions
Farmer Decision Making
• 90 farmers interviewed
• Questions open-ended: described area farming systems, conservation practices, nutrient management, water quality, and willingness to trade
• 92.5% cropland farmers using conservation tillage. Practice started over 40 years ago.
• 62% pasture-based farmers using exclusion fencing. Practice started in mid-1990s.
• Nutrient management is not viewed as a conservation practice.
• Most farmers were very negative about trading as they thought the development community should meet their obligations.
Conclusion: The Policy Is Flawed
Setting baseline water
quality standards matters.
If all agricultural lands
implement riparian buffers,
water quality goals
CANNOT be met.
Exclusion fencing can
reduce sediment, TN, and
TP > 50% from pastures.
Nutrient management may
have limited value for
croplands in this watershed
There is only enough
agricultural lands for one-
year of buffer installation.
Trading WILL NOT work.
Farmers are NOT
interested in trading. Most
farmers using conservation
tillage and many using
exclusion fending.
Determine
source
contributions
Provided agricultural community, city officials, and regulators with knowledge about what can and cannot be accomplished through agricultural conservation practices, including trading.
Acknowledgements • Funding
– USDA NIFA (#2011-05151)
– NC DENR, USEPA 319 pass-through funds
• Technical Support@ NC State University, Soil Science Department
– Wes Childres
– Ashleigh Hammac
– Rob Austin
• Farmers, and Soil and Water Conservation and extension personnel
Questions