Tracking Agricultural Water Use from Space

1. 0:07Soybeans, wheat, sugarbeets, corn. Nebraska is one of the biggest agricultural producers in the UNited States.
2. 0:16Field to field, crop to crop, every farmer uses a different amount of water. How do we keep track of such diverse water use?
3. 0:25The Landsat satellites gives us the ability to see individual fields. We can see what they are growing in each field and how much water is being consumed from each field.
4. 0:43So that it's a great satellite that gives us so much information about our planet
5. 0:53we use what we call surface energy balance. We know the amount of energy coming in from sunlight. Some of that energy is
6. 1:02released as heat and measured by Landsat's infrared sensors. At the same time
7. 1:09water from transpiration cools the surface, lowering the temperature of the fields
8. 1:16and limiting the amount of heat seen by the thermal sensors.
9. 1:20And we solve the energy balance for all these
10. 1:24components. The energy balance then yields the ET which is the water that was consumed.
11. 1:30We receive a monthly data set of metric ET data so we've got for May, June, July, August, September, we are getting inches of water used on the landscape so it covers the whole entire NRD
12. 1:52Let's take an aerial view of this. Landsat measures the health of individual plants and the temperature of the land
13. 2:04as we move into summer temperatures increase. Irrigated fields look cool because water evaporates from the soil and transpires from the
14. 2:13plants. You can see ET peak midway through the growing season when corn needs the most water.
15. 2:22By tracking monthly ET resource managers know how much water each field has used. The Central Platte
16. 2:30Natural Resources District uses these measurements to plan their water budget.
17. 2:35We need to maintain a balanced groundwater aquifer system. We don't want to deplete it. We don't want to overfill it because if we overfill it it runs out
18. 2:46but, yeah, that's our goal. It's to maintain the large amount of irrigation we have here in the valley.
19. 2:53and being able to do that on a sustainable basis.
20. 2:59Metric, the system used to develop ET, was developed in the early 2000s. Today it's being used by 15 states across the United States.
21. 3:08Water is important in this region and having this data now really helps us to use that water wisely.
22. 3:18And make wise decisions

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