Page 74 - GIS for Science Technology Showcases

ANALYZING GLOBAL WATER
QUALITY OVER TIME A blueprint for Sustainable Development Goals
Emily Smail, GEO Blue Planet; Dany Ghafari, UNEP; and Keith VanGraafeiland, Esri
Eutrophication is a process driven by nutrient enrichment of water, especially compounds of nitrogen or phosphorus, according to the European Commission. The process leads to increased growth, primary production, and biomass of algae, resulting in adverse changes in the balance of organisms and water quality. Monitoring changes in chlorophyll provides information about biomass changes that may be related to nutrient enrichment. The United Nations Environment Program (UNEP), GEO Blue Planet, and Esri partnered to develop a new chlorophyll index to support UN Sustainable Development Goal (SDG) Target 14.1, which aims to prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities, including marine debris and nutrient pollution. The statistical approach uses satellite data and GIS.
Why is SDG Target 14.1 important?
Many countries depend on their coastal ecosystems to drive essential sectors of their economies, such as tourism, fisheries, and natural resources. These economies provide sustainable food to their populations. Fertilizers and other chemicals used on land disperse into the near-coastal ocean and cause blooms in marine algae that disrupt ecosystems and human health. For instance, some of these algal blooms release toxins that kill fish and other marine life and significantly impact humans with breathing difficulties. Other types of algal blooms may result in dead zones, where oxygen becomes so depleted in the water that marine life suffocates and dies. SDG Target 14.1 is part of a larger goal that aims to conserve and sustainably use the ocean, seas, and marine resources. In all, the United Nations has adopted 17 SDGs that aspire to address climate change, improve health and education, reduce inequality, and achieve world peace and prosperity.
Knowledge transfer
Using ArcGIS Pro, a workflow was developed to globally identify and quantify the number and severity of eutrophication events in nearshore waters. A group of ocean color and statistics experts formulated the initial workflow. They provided the data and proposed a method for quantifying eutrophication based on satellite-derived chlorophyll measurements. Esri provided insight on how to scale and execute its method using GIS. This experience is a textbook example of collaborative science powered by GIS, more directly involving Esri in the SDG process.
The United Nations adopted and publicized this GIS-based method in the most recent update of the Global Manual on Ocean Statistics.
Repeatable science
ArcGIS Pro is effective for creating a repeatable and understandable workflow essential for good science. Esri turned to a visual programming language within ArcGIS Pro called ModelBuilder to build geoprocessing workflows that automate and document spatial analysis and data management processes. The program helped Esri produce and report results for sub-indicator one and sub-indicator two. Sub-indicator one focuses on annual reporting, beginning in 2005, and compares each year to a baseline to identify potentially anomalous eutrophication events or deviations from the baseline. Sub-indicator two focuses on monthly reporting and classifies anomalous values as moderate, high, or extreme based on the 90th, 95th, and 99th percentiles, respectively. Results are broken down for exclusive economic zones in each coastal country to understand how chlorophyll-a deviations and anomalies (as a proxy for water quality) change over time.
Community engagement
The project uses ArcGIS Hub, a community engagement platform that organizes people, data, and tools through information-driven initiatives to disseminate the results and engage with the community. Collaborative team members manage and update the ArcGIS Hub site to keep the public informed as the project progresses and results are published.
208 GIS for Science
This ArcGIS Pro workflow globally identifies and quantifies the number and severity of eutrophication events in nearshore waters.