MAPPING EPISODIC FLOWS ON THE DOUGHERTY PLAIN: A PILOT ANALYSIS USING A NOVEL LANDSAT-8 NDWI PROCESSING TOOL

The Dougherty Plain is a physiographic province characterized by deep sands, vuggy limestone bedrock, and deeply incised streams heavily developed for agriculture and plantation forestry. Episodic flows (~2-3 year return period) connect depressional wetlands to nearby streams after intense precipitation events. One challenge to understanding the function of episodic flows in depressional wetland ecology is a general lack of data on frequency and duration of events. Our objectives for this project were to: i) create and pilot a tool to identify episodic flows on the Dougherty Plain using NDWI generated from landsat data, ii) test the tool at a known flow locations, and iii) dockerize the tool to make it easily and readily available. We developed a tool to automate and simplify the process of generating and analyzing NDWI from Landsat products. Our tool automatically un-compresses bulk downloaded landsat 8 imagery, crops images to customizable bounding box coordinates and removes days with high cloud cover. Subsequently, NDWI is generated from acceptable images and then stored in an easily accessible format organized by date with the option to create a time series GIF. Episodic flow periods were identified during February of 2017 and February-March of 2019. We evaluated the tool through precipitation records corresponding to identified flow events within a two week margin of flows identified using NDWI.