Percent Cropped Area Project 

Update

September 20, 2011

Marietta Echeverria

R. David Jones

Chuck Peck

Andrew Shelby

Shelly Thawley

Nelson Thurman

1
Overview

• Project Description

• Project Update

• Next Steps

2
Project Description

• Update to reflect latest USDA Census of 

Agriculture data and National Land Cover Dataset

– National PCAs for corn, soybeans, wheat, cotton and 

total crop

– Regional (HUC-2) PCAs

• Develop PCAs for turf, orchard/vineyard, 

vegetable and rice*

• Consider using Hydrologic Unit Code-10 (HUC-10) 

or HUC-12

• Incorporate Drinking Water catchment data when 

available

* Implementation is under consideration

3
Project Description

• Distinguishing HUC sizes

• HUC-8

2,267 subbasins

avg. 703 sq. miles (450,000 acres)

• HUC-10

22,000 watersheds

40,000-250,000 acres

• HUC-12

160,000 watersheds

3,000-40,000 acres

HUC-8

HUC-10

HUC-12

4
Sample Corn 

PCA – Eastern 

Nebraska

Red Polygons – HUC-8 watersheds

Blue Text – HUC-8 area (km2)

Multi-colored polygons – counties

Black text – Corn area in county (km2)

Brown pixels – NLCD Agriculture pixels

Purple text – Corn PCA

5
Project Update

• Completed

– Draft PCAs have been determined for HUC-8, 10 and 

12 watersheds for all new and established crop groups 

in all HUC-2 Regions

– QA using modeling results and monitoring data

• In progress

– QA of GIS methods

– QA using aerial photography

– Crop group aggregation

– Revision to PCA guidance

6
Maximum PCA by crop group

Crop Group HUC-8 HUC-10 HUC-12

Corn 60.9% 65.5% 79.5%

Cotton 33.1% 51.4% 65.4%

Orchard/Vineyard 23.4% 39.7% 47.5%

Rice 20.8% 36.4% 42.5%

Soybean 46.1% 54.1% 77.5%

Vegetable 29.2% 39.5% 63.7%

Wheat 38.1% 51.0% 58.8%

Turf* 45.2% 61.8% 72.6%

Total Crop** 90.5% 95.3% 100.0%

* Does not include sod farms

** Does not include turf 7
HUC-2 Watersheds

8
HUC02 Corn Cotton Orchard/

Vineyard

Rice Soybean VegetableWheat Turf

Total 

Crop

01 1.8% 0.0% 0.3% 0.0% 0.0% 3.2% 0.0% 23.7% 12.5%

02 19.7% 1.6% 1.3% 0.0% 13.6% 3.2% 6.2% 39.1% 34.3%

03 9.2% 13.8% 15.3% 0.4% 12.6% 7.2% 4.4% 31.3% 41.3%

04 31.0% 0.0% 3.8% 0.0% 38.4% 5.2% 11.3% 45.2% 80.6%

05 45.5% 0.2% 1.7% 0.0% 33.5% 0.5% 8.4% 21.6% 80.9%

06 13.7% 5.4% 0.5% 0.0% 11.3% 0.3% 2.9% 14.4% 35.1%

07 60.9% 0.0% 0.1% 0.0% 35.0% 3.7% 12.3% 42.2% 87.8%

08 29.9% 23.1% 0.3% 19.4% 46.1% 1.3% 15.2% 34.6% 86.1%

09 36.6% 0.0% 0.0% 0.0% 34.1% 3.1% 33.2% 9.0% 90.5%

10 56.3% 0.0% 0.7% 0.0% 34.0% 0.4% 34.0% 14.7% 87.3%

11 18.5% 10.4% 1.9% 17.5% 24.7% 0.5% 38.1% 12.4% 74.9%

12 13.9% 33.1% 1.4% 3.5% 1.1% 1.9% 18.1% 34.3% 68.6%

13 2.5% 3.0% 1.9% 0.0% 0.1% 2.5% 4.0% 5.4% 44.2%

14 2.0% 0.0% 0.2% 0.0% 0.0% 0.4% 5.0% 2.1% 13.2%

15 0.9% 4.6% 1.5% 0.0% 0.0% 8.6% 3.5% 14.7% 18.9%

16 1.1% 0.0% 0.5% 0.0% 0.0% 0.4% 6.2% 15.2% 25.3%

17 8.5% 0.0% 4.7% 0.0% 0.0% 6.4% 29.2% 28.7% 65.8%

18 7.9% 7.1% 23.4% 20.8% 0.0% 29.2% 5.6% 39.7% 60.8%

HUC-8 PCAs

9
HUC-10 PCAs

HUC02 Corn Cotton Orchard/

Vineyard

Rice Soybean VegetableWheat Turf

Total 

Crop

01 6.6% 0.0% 0.6% 0.0% 0.1% 5.0% 0.1% 39.2% 19.7%

02 33.6% 3.7% 5.8% 0.0% 22.9% 6.6% 14.8% 55.3% 48.9%

03 20.9% 26.3% 25.1% 2.1% 26.8% 14.7% 13.0% 53.0% 93.6%

04 40.7% 0.0% 9.0% 0.0% 47.3% 9.1% 12.2% 61.8% 89.9%

05 56.9% 0.5% 3.2% 0.0% 41.6% 1.9% 11.3% 52.8% 92.5%

06 27.4% 10.9% 3.0% 0.0% 21.2% 0.9% 5.7% 30.7% 56.8%

07 71.0% 0.4% 0.7% 0.2% 50.9% 15.8% 23.5% 51.0% 92.9%

08 38.1% 36.2% 0.6% 29.6% 54.1% 3.0% 18.3% 55.6% 93.8%

09 41.8% 0.0% 0.0% 0.0% 39.2% 4.9% 41.8% 32.2% 95.3%

10 65.5% 0.0% 2.3% 0.0% 38.9% 2.1% 51.0% 51.7% 94.7%

11 26.6% 20.3% 2.9% 36.0% 38.0% 2.0% 46.6% 32.3% 87.8%

12 28.0% 51.4% 3.8% 7.3% 3.4% 4.7% 30.9% 48.2% 84.0%

13 3.0% 5.3% 6.5% 0.0% 0.1% 14.5% 12.5% 25.4% 44.2%

14 7.1% 0.0% 0.7% 0.0% 0.0% 3.1% 8.9% 13.1% 23.4%

15 1.9% 8.1% 5.6% 0.0% 0.0% 27.3% 11.0% 27.5% 53.1%

16 3.1% 0.0% 2.2% 0.0% 0.0% 1.0% 10.8% 18.2% 40.2%

17 21.6% 0.0% 18.7% 0.0% 0.0% 14.6% 41.5% 44.1% 92.2%

18 14.0% 21.7% 39.7% 36.4% 0.0% 39.5% 8.2% 51.5% 93.9%10
HUC-12 PCAs

HUC02 Corn Cotton Orchard/

Vineyard

Rice Soybean VegetableWheat Turf

Total 

Crop

01 16.8% 0.0% 2.3% 0.0% 0.1% 11.3% 0.1% 45.6% 45.0%

02 39.9% 6.2% 6.7% 0.0% 28.2% 9.6% 18.2% 65.7% 68.9%

03 30.8% 32.8% 47.5% 2.1% 40.8% 37.1% 19.7% 72.6% 93.6%

04 49.6% 0.0% 11.1% 0.0% 50.2% 18.6% 13.5% 71.8% 94.2%

05 64.6% 0.9% 4.7% 0.0% 48.9% 2.8% 16.5% 68.5% 95.3%

06 36.6% 30.5% 5.0% 0.0% 22.5% 2.1% 8.6% 59.9% 60.0%

07 79.5% 1.1% 1.5% 0.4% 77.5% 20.4% 30.7% 68.1% 96.0%

08 43.1% 47.0% 1.5% 42.5% 58.4% 4.3% 20.7% 57.2% 96.0%

09 45.9% 0.0% 0.0% 0.0% 40.4% 5.0% 44.5% 35.5% 100.0%

10 73.7% 0.0% 3.0% 0.0% 47.9% 2.5% 61.0% 61.4% 97.0%

11 39.1% 34.7% 10.3% 41.6% 44.0% 12.7% 57.5% 51.8% 94.4%

12 33.6% 65.4% 6.3% 14.8% 5.3% 4.7% 44.8% 54.8% 96.8%

13 8.5% 16.9% 11.7% 0.0% 0.1% 38.0% 14.8% 43.3% 66.1%

14 14.1% 0.0% 3.3% 0.0% 0.0% 10.8% 16.3% 20.3% 51.4%

15 5.9% 20.6% 7.2% 0.0% 0.0% 27.3% 11.4% 49.3% 62.7%

16 6.3% 0.0% 4.5% 0.0% 0.0% 2.3% 17.6% 44.8% 66.0%

17 30.0% 0.0% 33.0% 0.0% 0.0% 19.3% 58.8% 50.4% 97.2%

18 18.1% 21.9% 46.1% 37.6% 0.0% 63.7% 10.6% 62.8% 94.4%11
Monitoring vs. Modeling QA

Corn Cotton Orchard/Vineya

rd

Rice Soybean

Fipronil Fluometuron Oryzalin Molinate Imazaquin

Atrazine Dicrotovos Phosmet Thiobencarb Bentazon

Acetochlor Cypermethrin Bromacil BensulfuronmethyalAcifluoren

Vegetable Wheat Turf All Cropland

Linuron Bromoxynil Iprodione Chlorthalonil

DCPA MCPA Triclopyr Diazinon

Cycloate Picloram

12
QA using aerial photography

• ImageConnect is being used to QA maximum 

PCAs in each region and for each crop group

• It has also been used to QA anomalous results 

influenced by the incorporation of surface 

water or country boundaries.

13
Crop Group Aggregation

• Combination PCAs are being made for each crop combination 

• Individual maximum PCAs are not additive and can only be 

aggregated at the watershed level

Grain combinations Turf combinations Other

Corn-Soybeans Turf-Corn VegetableOrchard/Vineyard

Corn-Wheat Turf-Cotton Rice-Vegetable

Corn-Cotton TurfOrchard/VineyardRice-Cotton

Soybeans-Wheat Turf-Rice

Soybeans-Cotton Turf-Soybean

Wheat-Cotton Turf-Vegetable

Corn-SoybeansWheatTurf-Wheat

14
Next Steps

• QA of GIS methods and results

• Finalization of associated guidance document

15