science meets policy: a case study from a regulated...

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 (%)






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





and projected

implementation of







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





and projected

implementation of










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





and projected

implementation of










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

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