Coastal wetlands play a prominent role in flood control, carbon circulation, and ecosystem. Due to sea level rise, the increasing impacts of hurricanes and strong storms on sediment erosion, and thermal expansion, coastal wetlands have experienced a wide range of stress-inducing changes. Monitoring the spatial patterns and rates of coastal wetland evolution is of critical importance for both research communities and management agencies.
However, such long-period data records tend to be lacking. To fill the data gap (with regard to Texas), this study aims to generate an annual wetland dataset over Texas that includes evolution mapping and erosion rate assessment from 1984 to 2021. The evolution/erosion maps were developed using the Landsat-based global surface water dataset (GSWD) from 1984 to 2020, and ~40,000 high spatiotemporal CubeSat images from 2009 to 2021. First, the National Wetland Inventory was adopted to determine the wetland location. The annual water occurrence mappings were calculated from GSWD, and the wetland pixels were identified on CubeSat images by the K-means classification algorithm in these locations. Then, the erosion rate was determined by the change of the wetland area along with the length of the coastline. The results indicate a good agreement (r2=0.78) with in-situ measurements. The mean erosion rate is around 0.71 m/year, and 76% of the sites have been eroded. In this study, the mean erosion rates from 1984 to 2009 are half of those from 2009 to 2020. This acceleration of erosion rate is consistent with the faster sea level rise rate, which has doubled during the second period (2009 to 2020) as compared to the first (1984 to 2009). In addition to retrospective research, the wetland maps developed in this study can also be used for predicting wetland evolution by analyzing the drivers of the historical erosion. Furthermore, high spatial resolution bathymetry information over Texas’ coastal area can be derived from the wetland maps in a future study.