Download Analysis of Relative Water Use Between Flood- and Drip

Analysis of Relative Water Use
Between Flood- and DripIrrigated Fields Deming, New
Mexico
David Jordan, PE, INTERA
Guillermo Martinez, PhD, INTERA
Amber Whittaker, INTERA
Rick Allen, PE, PhD, University of Idaho
Study Objective
 Conversion to drip-irrigation has been
funded by NMISC to promote water
conservation in the Deming area
 We sought to compare water use
between drip-irrigated and flood-irrigated
fields
 We used field data combined with
satellite imagery to quantify relative
water use difference
Location Map
Study Area
Irrigation Methods: Flood
Irrigation Methods: Sprinkler
Irrigation Methods: Drip
Field Application Efficiency
Irrigation
Method
Amount of
Water Used by
Crop
Return Flow
Flood irrigation
60%
40%
Sprinkler
irrigation
75%
25%
Drip irrigation
90%
10%
Source: www.fao.org
Field Data – 103 Fields
 Identify:
 Crop type
 Irrigation Method
 Measure location of field
Field Summary
Crop Type
Alfalfa
Bean
Chile
Corn
Cotton
Milo
Pecan
Total
Irrigation Method
Drip
Flood
Sprinkler
11
1
4
1
9
2
9
4
1
19
11
11
10
3
7
63
35
5
Total
16
1
11
14
30
21
10
103
Field Results
After evaluating field irrigation method and extent, cotton and milo
fields were selected to study differences between drip and flood
irrigation methods.
Landsat Satellite Data for
Evaluating Agricultural Practices
 Family of satellites operating since
1972
 Orbits at ~450 miles above the earth
 Passes over every 16
days
 Each image (scene) is
about 100 miles on a
side
What Does Landsat “See”?
Landsat Resolution
Field: 14 acres
Landsat Pixel: 0.22 acres
Example Landsat Image
Natural color (3, 2, 1)
False color (4, 3, 2)
Temperature Data
 Using a different band of the spectrum to “see”
 Example: Thermal imaging using infrared
wavelengths
Evaporation Causes Cooling
 “Swamp cooler”
analogy
 Use temperature
of fields to
determine
relative water
consumption
Plants Cool the Air
 Plants transpire water and water evaporates from the soil
 Evaporation uses heat energy and cools the
surroundings:
ET = F Water Use
Temperature Results
Hot
Temperatures
Bare dirt:
110º F
Fields:
85º F
Cool
August 5th 2012
Example Temperature Data
Cotton and
Milo
 Drip fields
 Flood fields
August 5th 2012
Average Temperature for Milo
Average difference: 3.9 degrees F
Average Temperature for Cotton
Average difference: 1.0 degrees F
Average Temperature for Corn
Average difference*: 7.8 degrees F
Summary
 Lower temperature = more overall water
usage (drip)
 Higher temperature = less overall water
usage (flood)
 Important – higher water usage indicates
more robust vegetation and hence higher
yield – more crop is produced resulting in
economic benefit
 We can show this using a vegetation index
Vegetation Index
 Normalized Difference Vegetation Index (NDVI)
 Ratio using near-infrared (Band 4) and visible
red (Band 3)
NDVI calculated on each pixel in the Landsat
image using image-processing software:
Band 4 - Band 3
NDVI 
Band 4  Band 3
NDVI Image
NDVI Can Show Relative Crop Yield
NDVI by Crop Type: Milo
NDVI by Crop Type: Cotton
NDVI by Crop Type: Corn
Field Comparison
Flood
Drip
Conclusions
 We are able to see a difference in
temperature between drip-irrigated and
flood-irrigated fields
 The lower temperature in drip-irrigated
fields indicates higher water consumption
 NDVI supports the temperature analysis
and indicates more robust vegetation and
higher relative yield
 Bottom line: more water used, but yield
is higher
Next Steps
 Run METRIC analysis to confirm the
findings based on NDVI and temperature
 METRIC can give us more quantitative
information on actual water usage
(evapotranspiration, or ET)
METRIC
Mapping EvapoTranspiration with high
Resolution and Internalized Calibration
Evapotranspiration =
net radiation – soil heat flux – heat flux to the air
Evapotranspiration
net
radiation
heat flux
to the air
soil heat flux
Preliminary METRIC Results
High
ET
Low ET
August 5th 2012
Preliminary METRIC Results
Thank you