THSCMP - MAT03

Tidehaven Middle and High School students collected data at MAT03 (Fig. 1) from 2005 until 2017. Tidehaven’s fall and spring field trips were scheduled to coincide with the Beach Clean-Up at Matagorda Bay Nature Park. Tidehaven ISD is no longer a participan03t in THSCMP but students from Van Vleck and Palacios High Schools continue to collect GPS vegetation line and shoreline data at the MAT03 site during their fall field trips.

figure 1

Figure 1. MAT03 at Matagorda Bay Nature Park.

The MAT03 is the Matagorda Bay Nature Park site is closest to the mouth of the Colorado River. MAT03 is on the up-drift side of the jetty at the mouth of the Colorado River. Understanding the impacts of coastal structures (in this case, a jetty) are critical to coastal management. The U.S. Army Corps of Engineers constructed a new north jetty at the mouth of the Colorado River between 2009 and 2010. GPS-mapped shorelines from September 2009 through September 2018 show a 115-m seaward movement of the shoreline position at MAT03 (Fig. 2). The shoreline and vegetation line position have been continuously moving seaward and volume has been increasing at this site throughout the study period (Fig. 2). The combination of the new jetty impounding sand on the updrift side and the decreased vehicular traffic at MAT03 has allowed for coppice dune formation to occur on the expanded backbeach area and for new vegetation to develop without being disturbed. On the field trips during the 2015–2016 and 2016–2017 academic years, it was documented that salt marsh plants have become established on the widened backbeach area in the swales between the coppice dunes.

Figure 2

Figure 2. Shoreline and vegetation line position change and sediment volume increase at MAT03 due to jetty construction at the mouth of the Colorado River.

The shoreline and vegetation line position have been continuously moving seaward and volume has been increasing at this site throughout the study period (Fig. 3). The combination of the new jetty impounding sand on the updrift side and the decreased vehicle access at MAT03 has allowed for coppice dune formation to occur on the expanded backbeach area and for new vegetation to develop without being disturbed. On the field trips during the 2015–2016 and 2016—2017 academic years, it was documented that salt marsh plants have become established on the widened backbeach area in the swales between the coppice dunes.
 

Figure 3

Figure 3. Changes in beach and dune volume, shoreline position, and vegetation line position at MAT03 on Matagorda Peninsula.