Identification of phreatophytic ecosystems depending on groundwater in Texas based on NVDI data

- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner
Sunday, 4 January 2015
Keisha K. Baxter, NSF Crest REU, New York, NY; and I. C. Perez and N. Krakauer

Groundwater dependent ecosystems (GDEs)refers to any biological life that depends o groundwater for its existence and survival. This study was performed to identify a class of these GDEs known as phreatophytes, which is vegetation that uses groundwater to survive. Due to increasing use of groundwater, by humans, ecosystems have been forced to survive on lessened amounts of water and several ecosystems have died as a result. In order to mitigate this issue, this research studies an area in Texas, called Spring Branch located near the Honey Creek State Natural Area, that has been proven to by USGS to have GDEs. In this research, two types of analysis will be conducted; seasonal and inter annual. Seasonal analysis will be performed for two months, within a dry season, having the largest difference in precipitation (PPT). The inter-annual analysis will be conducted between the wettest and driest years based on the Palmer Drought Severity Index (PDSI) for the 2000-2012 time series. The difference NDVI will be obtained by taking the difference of the two images. The theory is that the smaller the difference, the higher the potential to be GDE. The seasonal analysis showed very little change in NDVI because of antecedent soil moisture that could have an effect in vegetation conditions for the image corresponding to the end of the dry season. However, inter-annual analysis showed that there is a great deal of locations that have potential to be accessing groundwater in the area. Implementing our methodology of identifying GDEs using remote sensing will enable us validate the use of remote sensing to identify GDEs as well as enable us to locate and create national maps of areas consisting go GDEs. This can further be used to prevent developers and land users from taking groundwater away from ecosystems that depend on it for their existence.