This is a part of the 2015 Fall VPS. For more VPS articles, click here
Category: Mapping Water Quality
Project Team: Coastal Texas Water Resources II
Team Location: Mobile County Health Department – Mobile, Alabama
Joe Spruce (NASA Stennis Space Center)
Bernard Eichold, M.D., Dr.PH (Mobile County Health Department)
This project was conducted to aid the National Park Service (NPS) in assessing the historical hydrology of the Laguna Madre located within Padre Island National Seashore. While the lagoon is now hypersaline, there is historical evidence indicating this was not always the case. It is hypothesized that the proliferation of the honey mesquite tree (Prosopis glandulosa) has contributed to the Laguna Madre’s increased salinity by tapping into groundwater, thereby reducing the amount of freshwater flow into the lagoon. The project team partnered with the NPS to analyze the suspected correlation between the occurrence of the mesquite trees and the salinity of the lagoon. NASA Earth observations were used in ArcGIS software and ERDAS IMAGINE to create time series maps and conduct data analyses. Landsat 5 data were used to create Land Use/Land Cover (LULC) maps to analyze the change in mesquite tree coverage compared to various soil types and underlying geology as well as to calculate the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Infrared Index (NDII). Thermal maps of the lagoon also were created using Landsat 5 data to identify thermal anomalies in surface water temperature. These anomalies could indicate possible inflow locations of groundwater to the lagoon. In situ and PRISM (Parameter elevation Regression on Independent Slopes Model) precipitation data were used to target months and years for analysis. Through these analyses, the NPS can improve future land management practices.