1. Mapping Historic Waterbodies using Landsat and QGIS Justin Epting USFWS, Pacific Southwest Region

2. Landsat data used in the analysis Study Area – Lahontan Valley, NV Includes Stillwater NWR 3 separate areas analyzed Data are needed for long- term planning in the region Legal mandate

3. Utilize mid infrared and green portions of the electromagnetic spectrum High reflectance of MIR by vegetation and the built environment Low reflectance of MIR by water Modified Normalized Difference Water Index (MNDWI) for Landsat : (Band2 – band 5)/(band 2 + band 5) Source: Modification of Normalized Difference Water Index (NDWI) to Enhance Open Water Features in Remotely Sensed Imagery, 2006. Xu, Hanqiu. International Journal of Remote Sensing 27(40), pp. 3025-3033. Theoretical Aspects - Remote Sensing for Water Mapping

4. Pros and Cons of Using MDNWI PROSCONS RepeatableMaps open water only, not vegetated wetlands Fast Efficient Accurate (open water) Pros & Cons of Using MNDWI

5. Landsat mission: Landsat 4: first high quality data available Landsat 5: ‘workhorse’ that operated from 1984 to 2013 Landsat 6 – failed to launch Landsat 7 – 1999 to present Landsat 8 – launched in 2013. Sensors upgraded. Excellent quality but also uses a different format than previous sensors. Entire archive available from USGS EROS via Earth Explorer (earthexplorer.usgs.gov) Utilizing Landsat for Historical Mapping

6. Year Month-DaySensor Path/Row 1990Sep-10Landsat 542/33 1991Aug-28Landsat 542/33 1992July-29Landsat 542/33 1993July-16Landsat 542/33 1994Aug-20Landsat 542/33 1995Aug-07Landsat 542/33 1995Aug-07Landsat 542/32 1996Aug-09Landsat 542/33 1996Aug-09Landsat 542/32 1997Aug-12Landsat 542/33 1997Aug-12Landsat 542/32 1998Aug-15Landsat 542/33 1998July 30Landsat 542/32 1999Sep-03Landsat 542/33 1999July 17Landsat 542/32 2000Aug-20Landsat 542/33 2001Aug-07Landsat 542/33 2002Aug-10Landsat 542/33 2003Aug-29Landsat 542/33 2004July-30Landsat 542/33 2005Aug-18Landsat 542/33 2006Aug-05Landsat 542/33 2006Aug-21Landsat 542/32 2007Aug-08Landsat 542/33 2007Aug-24Landsat 542/32 2008Aug-10Landsat 542/33 2009July-28Landsat 542/33 2010Aug-16Landsat 542/33 2011Aug-03Landsat 542/33 2011Aug-03Landsat 542/32 2012July-28Landsat 742/33 2012Aug-29Landsat 742/33 2013Aug-08Landsat 842/33 2014Aug-27Landsat 842/33 2015July-29Landsat 842/33 Landsat data used in the analysis Landsat Scenes Used in the Analysis Primarily L5 but also L7 and L8 L7 scenes had to be merged to fill in missing data

7. Landsat data used in the analysis Methodology 1.Select and download imagery using semi-automated classification plugin (SCP tool) in QGIS 2.Pre-process imagery (convert to TOA reflectance) 3.Calculate the MNDWI using band calc 4.Recode to boolean values 5.Convert from raster to polygon 6.Dissolve polygons 7.Calculate acres for each area/yr 8.Tabulate areas for each of the 3 regions

8. Landsat data used in the analysis Methodology Landsat TM Image (4,3,2 false color), 1990 Modified Normalized Difference Water Index Recoded MNDWI (0,1) Creation of Dissolved Polygons

9. Landsat data used in the analysis GOAL: Acres per Year Primarily L5 but also L7 and L8 L7 scenes had to be merged to fill in missing data