u.s. department of the interior u.s. geological survey variability and trends in irrigated and...

U.S. Department of the InteriorU.S. Geological Survey

Variability and trends in irrigated and non-irrigated croplands in the Central U.S.Jesslyn Brown, USGS EROS

Acknowledgments

Shahriar Pervez (Inu tec) Susan Maxwell (Biomedware) Brian Wardlow (NDMC—UNL) Karin Callahan (NDMC—UNL) Ron Zelt (USGS Nebraska Science Center)

Irrigation ground reference data providers: California Department of Water Resources Idaho Water Resources Board University of North Dakota

Irrigated Agriculture in U.S.

Over 23 m hectares (233 K km2) of U.S. croplands are irrigated

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Water used in irrigation Total withdrawl% used in irrigation

a) b)

Irrigation is an agricultural practice

Agricultural intensification Drivers for expansion in the U.S. (early to mid

20th century) Climate uncertainty Rising demand for farm products—rising (urban) population,

rising sophistication in diet Increasing crop yields (esp. in moisture limited environments like

the American West) Raising farm revenues Federal policies to develop water supplies Development of new technologies for groundwater mining and

irrigation equipment

Gollehon, N., Quinby, W., 2000. Irrigation in the American West: Area, water and economic activity. International Journal of Water Resources Development 16, 187-195.

Requirement for Geospatial Data on Irrigation Status (Land Use Data)

Irrigation status is a required data layer in drought monitoring In drought monitoring, we need to separate locations that receive

supplemental moisture from those that don’t

Repeatable and reliable process Coast to coast coverage (48-state) Moderate resolution (able to resolve median

irrigated field size in U.S.) Direct and spatially-detailed modeling

strategy

Additional Applications for Irrigation Land Use Data

Assess and evaluate water-quality trends in ground and surface-waters

Model evapotranspiration/energy and water exchange

Estimate water supply/use

Source: USDA 2002 Census

2002 MIrAD-US

MODIS Irrigated Agriculture Dataset for the United States (MIrAD-US): Data and Methodology Model Inputs

Irrigated area statistics from USDA NASS 2002 Census of Agriculture

2002 annual peak MODIS NDVI (250 m)

2001 NLCD

Model Approach – Runs on a County Domain

MODIS annualpeak NDVI

Area of 1st peak> USDA irr. acg.

Masking :Peak NDVI for

agricultural land only

NLCD

Area of 2nd peak> USDA irr. acg.

Area of nth peak> USDA irr. acg.

Area of last peak> USDA irr. acg.

yes no

no

no

no

yes

yes

yes

Peak NDVI cells above or equal to threshold peak NDVI are identified as irrigated

All the peak NDVI cells are considered irrigated

The cumulative area for peak NDVI is compared with irrigated

area reported by USDAby county

Loop for defining peak NDVI threshold for irrigated crops

Peak NDVI rankDesc. order

Pervez & Brown (2010) Remote Sensing 2(10) 2388-2412.

MIrAD Model Assumptions

Irrigated crops commonly exhibit higher annual peak NDVI values than non-irrigated crops in the same local area.

The growing season peak NDVI, at any time it occurs, will vary for each crop and for each geographic region of the U.S.

The difference in peak NDVI between irrigated and non-irrigated crops will be enhanced under non-optimal precipitation conditions (e.g., drought).

MODIS 250-meter NDVI time series

Annual Peak NDVI

2002 Drought

Beans & Corn

Blue line : IrrigatedRed line : non-irrigated

Peak NDVI for Separating Irrigated and Non-irrigated Crops

Irrigated and non-irrigated corn in both years

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Irrigated cropNon-irrigated croppeak-irrnon-irr-peak

2002: Irrigated and non-irrigated dry beans2006: Irrigated dry beans and non irrigated corn

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2002: Irrigated and non-irrigated pasture2006: Irrigated corn, non-irrigated millet

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Irrigated crop Non-irrigated cropIrrigated crop peak NDVI non-irrigated crop peak NDVI

2002: Average NDVI for irrigated and non-irrigated corn, dry beans and pasture

2006: Average NDVI for irrigated corn and dry beans, and non-irrigated corn and millet

CornCorn

Dry Beans

Pasture

Crop Avg.

Corn

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MIrAD-US Accuracy Error Matrix

Site Category2002 2007

Producers’ Overall Kappa Producers’ Overall Kappa

CaliforniaIrrigated 0.75

0.92 0.750.71

0.92 0.74Non-Irri. 0.97 0.97

Great Plains

Irrigated 0.760.80 0.58

0.900.88 0.68

Non-Irri. 0.80 0.80

Eastern Snake Plain

Aquifer-Idaho

Irrigated 0.75

0.94 0.77Non-Irri. 0.98

Regional accuracies were over 88% Accuracy at national scale is unknown

U.S. Land Use Change: Irrigation Status

In 2002, 22.4 million ha (55.3 million acres) were irrigated

In 2007, 22.9 million ha (56.6 million acres) were irrigated

Net increase of 2.3% nationally Nationally, the proportion of harvested

croplands that are irrigated has increased slightly during the last 15 years, according to the USDA Agricultural Census.

Irrigation Change (2002 to 2007)

Top ten States Irrigated area in million Ha.

Irrigation Consistency Top ten States

State % changed (spatially)

% net change

Nebraska 3.68 CA 22.4 -7.7California 3.23 ID 23.3 0.1Texas 2.02 UT 25.6 4.7Arkansas 1.88 NV 26.7 0.5Idaho 1.34 AZ 27.2 -6.1Kansas 1.17 NE 27.4 16.3Colorado 1.13 WY 28.6 0.4Montana 0.81 CO 35.1 8.4Oregon 0.73 WA 35.2 -5.2Washington 0.71 AR 36.2 6.0

Spatial Change in Irrigated Lands between 2002 and 2007

High Plains Aquifer

The HPA underlies ~450 thousand km2 (8 states: SD, WY, NE, CO, KS, OK, NM, TX)

Most intensively used aquifer in the U.S. Ground water use primarily for irrigated

agriculture More than 60% of the aquifer lies under one

state, Nebraska

Irrigation Change across the High Plains Aquifer

State

Irrigated area in haCommon area

between 2007 and 2002

New in 2007 Lost from 2002Net

Change in %

2007 2002 in ha % in ha % in ha %

NE 3,422,013 2,942,856 2,220,438 75.5 1,201,575 40.8 722,419 24.5 16.3

TX 1,469,288 1,451,419 871,469 60.0 597,819 41.2 579,950 40.0 1.2

KS 1,022,581 969,206 454,894 46.9 567,688 58.6 514,313 53.1 5.5

CO 270,656 270,413 138,400 51.2 132,256 48.9 132,013 48.8 0.1

WY 111,144 116,644 70,500 60.4 40,644 34.8 46,144 39.6 -4.7

OK 105,406 103,850 51,113 49.2 54,294 52.3 52,738 50.8 1.5

NM 96,525 125,531 66,206 52.7 30,319 24.2 59,325 47.3 -23.1

SD 7,400 5,469 1,794 32.8 5,606 102.5 3,675 67.2 35.3

Total 6,505,012 5,985,387 3,874,812 64.7 2,630,200 43.9 2,110,575 35.3 8.7

Irrigation Change

Factors Causing Recent Irrigation Change in the HPA Economic incentives

Rising commodity prices Rising land values

Government policies (e.g. water reg.) Demand for corn (biofuels, livestock feed,

food) Climate

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Soybeans

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USDA NASS

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Hec

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sCorn (Grain) Annual Area Harvested in the High Plains Aquifer

Irrigated Non-irrigated Irrigated (2002-2007)

Linear (Irrigated) Linear (Non-irrigated) Linear (Irrigated (2002-2007))

a.

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Corn (Grain) Annual Yields in the High Plains Aquifer

Irrigated Non-irrigated DifferenceLinear (Irrigated) Linear (Non-irrigated) Linear (Difference)

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Irrigation and 2012 Corn Yields

Recent article from U.S. Department of State“The 2012 drought — the worst in more than 50 years

for several U.S. states — reduced yields in many states, but less so in Nebraska. It is expected to end its 2012 summer growing season with its eighth-largest grain yield in history while drawing down its aquifer just 1 percent, Lenton said. More than 65 percent of the High Plains Aquifer, the largest in North America, lies beneath the state.”

Read more: http://iipdigital.usembassy.gov/st/english/article/2012/09/20120925136551.html#ixzz296ElvEHK

Average Reported Value of Nebraska Farmland

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Dryland Cropland (noirrigation potential)

Dryland Cropland(irrigation potential)

Gravity Irrigated Cropland

Center Pivot IrrigatedCropland

From 2002 to 2007, NE land values rose 48% on average, 51% for CP Irrigated Cropland.

Demand for Corn Due to Ethanol

Nebraska Water Policy

Published by the Nebraska Department of Natural Resources

Consequences of Irrigation Expansion

Increased crop productivity Changing boundary layer energy and water

exchange Changes in ET

Groundwater storage Regional climate Water quality

Consequences of Irrigation Expansion

Increased crop productivity Changing boundary layer energy and water

exchange Changes in ET

Groundwater storage Regional climate Water quality

Fischer, B.C. et al. Digital map of the saturated thickness of the High Plains aquifer in parts of Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas and Wyoming, 1996-97.

HPA Water Budget Components

Stanton, J.S., Qi, S.L., Ryter, D.W., and others, 2011, Selected approaches to estimate water-budget components of the High Plains, 1940 through 1949 and 2000 through 2009: U.S. Geological Survey Scientific Investigations Report 2011–5183, 79 p.

(Values enclosed in parantheses are given in million acre-feet per year.)

Water level changes in the HPA

Predevelopment to 2009

Average water level change -14.0 ft

McGuire, V.L., 2011, Water-level changes in the High Plains aquifer, predevelopment to 2009, 2007–08, and 2008–09, and change in water in storage, predevelopment to 2009: U.S. Geological Survey Scientific Investigations Report2011–5089, 13 p.

Water level changes in the HPA

New irrigation in 2007

McGuire, V.L., 2011, Water-level changes in the High Plains aquifer, predevelopment to 2009, 2007–08, and 2008–09, and change in water in storage, predevelopment to 2009: U.S. Geological Survey Scientific Investigations Report2011–5089, 13 p.

Summary

Regional variability in spatial change irrigated agriculture from 2002-2007 Nationally +2.3% HPA +8.7% NE +16.3%

Various causes and consequences Future monitoring will be important especially

as irrigation effects sustainable water use (ground and surface water) given future food/fuel requirements

Plans/Opportunities

Run MIrAD model for 2012 2012 Agricultural Census statistics 2012 peak MODIS NDVI 2011 NLCD

Crop-specific irrigated agriculture maps (utilizing crop data from USDA CDL)

Prototype methods at the Landsat scale

References

Brown, J.F. and Pervez, M.S., 2014, Merging remote sensing data and national agricultural statistics to model change in irrigated agriculture, Agricultural Systems, 127, 28-40; doi: 10.1016/j.agsy.2014.01.004.

Pervez, M.S. and Brown, J.F., 2010, Mapping irrigated lands at 250-m scale by merging MODIS data and national agricultural statistics, Remote Sensing, 2(10), 2388-2412; doi:10.3390/rs2102388.

Brown, J.F., Pervez, M.S., and Maxwell, S., 2009. Mapping irrigated lands across the United States using MODIS satellite imagery. In Remote Sensing of Global Croplands for Food Security, Eds., Thenkabail, P.S., Lyon, J.G., Biradar, C.M., and Turral, H., London, Taylor and Francis, Boca Raton, p. 177-198.

jfbrown@usgs.gov

2002 and 2007 MIrAD-US can be downloaded fromhttp://earlywarning.usgs.gov/usewem/