When Esri (Redlands, Calif.) first released the ArcGIS spatial analysis platform in 1999, it empowered users to visualize abstract data in a way that put computer-assisted watershed planning (literally) on the map. Just under two decades later, the open-source platform now enables seamless map-sharing, intuitive rendering features, and has inspired a dedicated circle of coders set on maximizing the tool’s capabilities.

At 19-years-old, Queensland Institute of Technology (Brisbane, Australia) student Alan Pearse grew up in the age of ArcGIS. And this year, the earth and statistical sciences student earned the 2017 Australian Esri Young Scholars Award for developing a new suite of ArcGIS tools that improves the platform’s capacity to inform stormwater decisions by watershed stakeholders.


Roadmap for runoff

19-year-old Alan Pearse of Queensland Institute of Technology (Brisbane, Australia) developed an add-on to popular geographical mapping platform ArcGIS that allows users to visualize how different types of watershed land use affect the path of stormwater runoff. Pixabay/Creative Commons.

ArcGIS has long been able to incorporate basic land use data into its water-flow visualizations. But, accurately predicting the unique effects of distinct types of land use on the travel path of runoff has remained a challenge.

GISUser, a news website for geographical mapping enthusiasts, spoke to Pearse about his project for an August article.

Because of the many site-specific variables at play in each visualization, ArcGIS considers the effects of land use on watersheds only in terms of surface area, ignoring whether that land is native or built, farmed or fallow, or porous or impermeable, Pearse said To get more specific than that would take hundreds of thousands of operations for each rendering, which would take weeks to complete with the basic ArcGIS program, Pearse told GISUser.

Pearse’s ArcGIS plug-in tool, called IDW-Plus, performs those operations in just hours.

“Some land may have more water pass through, or be closer to a stream where more water is likely to collect and reach the end of the line,” Pearse explained. “These areas, therefore, have a greater impact [on stormwater runoff]. IDW-Plus takes factors like these into account and gives us a far better understanding of what is ending up in our lakes and rivers, and, eventually, in our oceans.”

IDW-Plus maps both the travel path of rainwater as it relates to watershed land use and gives watershed managers an idea of what chemicals and nutrients are likely to be carried into waterways in runoff.


International acclaim

As the winner of Esri Australia’s 2017 Australian Young Scholars Award, Pearse was invited to present his toolbox in San Francisco at the annual Esri User Conference.

“Mr. Pearse’s work exemplifies the spirit of the Young Scholar award, which enables our tomorrow’s leaders to use spatial technology to deliver data-driven solutions,” Esri Australia Managing Director Brett Bundock told GIS User. “And with the demand for geospatial disciplines within Australian universities growing, it is rewarding to see ArcGIS adapted to deliver for the next generation of users.”

Pearse notes that IDW-Plus already is enjoying international attention and being applied in real-world situations. For example, researchers from the U.S. Geological Survey are using the suite to model how natural hazards could threaten the health of America’s water resources, he said.

IDW-Plus is available through the U.S. Department of Agriculture website as a free, open-source plugin for ArcGIS.