Student-Driven Project Aims to Help Farmers and Environment

That’s the goal of a University of Alabama in Huntsville (UAH) student-driven project in the Lake Guntersville, Ala., watershed that’s using NASA geospatial technologies and U.S. Department of Agriculture crop data, along with university aquatic plant growth research.

Senior Earth System Science majors Casey Calamaio and Kel Markert have teamed up with advisors Dr. Rob Griffin of UAH and Dr. Jeff Luvall of NASA’s Global Climatology and Hydrology Center to examine the inherent relationship between aquatic vegetation growth and water drainage near locations of high agricultural activity.

“We’d like for the end result of this to be a type of product that you can use to predict the results of various activities on the watershed,” said Dr. Griffin. The product would use historical data on crop acreage and type, combined with annual agricultural activity data and watershed maps to be predictive of aquatic growth, he said.

As a student-driven effort, Dr. Griffin said Calamaio and Markert presented the project to NASA’s DEVELOP program in a competitive process to get it funded. They work as paid interns for NASA as the research is being done. Markert is currently the Marshall Space Flight Center (MSFC) center lead for DEVELOP.

By combining topographical mapping from NASA satellites and Space Shuttle missions with U.S. Dept. of Agriculture National Agricultural Statistics Service data to show where crops are grown and the types of crops, “you can use the digital satellite information to estimate where the crop was planted over the years and what effects of various crops are on the lake vegetation further downstream,” said Dr. Griffin, an assistant professor in Atmospheric Science.

“NASA is always looking for ways to use its satellite imagery to benefit society,” Dr. Griffin said. “What we used from the Shuttle was elevation data to identify our sub-watersheds, where essentially after a rain event occurs, the water flows to a drainage area.”

Measuring the lake’s annual aquatic plant growth and correlating that to periods of agricultural activity like field preparation, fertilizing, herbicide or pesticide spraying and harvest can illustrate when runoff from these activities is affecting the lake, Calamaio said. Using multispectral satellite imagery in the near-infrared and red wavelengths, the researchers created vegetation indices for observing aquatic vegetation growth in the lake and seasonal variations for Lake Guntersville.

The research could save farmers money by showing them how much of the expensive inputs they apply to crops are not staying in place to do their intended jobs. The researchers are working to make it an accurate prediction tool for the future consequences of various farming practices like no till planting or more precise fertilizer, herbicide and pesticide application using GPS data.

Now that the Tennessee Valley Authority is no longer spraying herbicides to kill aquatic weeds, controlling their growth from the nutrient input side has become more important. Controlling the conditions that lead to algae blooms and aquatic weeds helps support the tourism industry at Lake Guntersville by keeping weeds from choking landings and harbors while preventing fish from eventually falling prey to possible mass deaths from oxygen depletion caused by the decay of plant matter in the water column.

That process is known as eutrophication, Calamaio said, where over-enriched waters allow native vegetation to be replaced with different species and biodiversity declines.

“Hopefully with this tool,” he said, “we will be able to create prevention measures to help better keep farm nutrients and chemicals with the crops.”