Restoration and Monitoring Methods

Cross-Section and Pebble Count

Each site has four cross-sections located at the beginning, the end, and two in the middle evenly spaced out. On March 12,  2018, our team performed surveys and pebble counts of each cross-section and longitudinally along the total 300 foot span of the creek including the 100 foot buffer located between the restored and control sites. The survey produces elevations for the data points allowing a holistic view of the shape and morphology of the creek. The pebble counts indicates the average substrate type and size that makes up the creek at the different sections. At the beginning of the restoration site, a riffle with mostly gravel substrate gives way down stream to slower pools with compacted shale.

 

 

 

 

 

 

 

 

 

 

 

 

Native Vegetation Restoration

Vegetation is an important aspect for stream bank stabilization. Roots help hold the soil in place reducing erosion. The above ground portion of vegetation slows down floodwaters dissipating the energy. This allows filtration of sediments and debris. The riparian corridor consists of a variety of species.

Species are designated as obligate, facultative wet, facultative, and upland. Obligate species grow right at the water’s edge where they survive with their roots in constantly inundated or saturated soil. Facultative wet species can grow slightly upland from the obligate species. They prefer saturated soils with seasonal inundation. Facultative species grow further up the banks of streams in slightly saturated to upland soils with tolerance to occasional flooding. Upland species prefer unsaturated soil.

The variety of species planted at the site include: cardinalflower (Lobelia cardinalis), obedient plant (Physostegia virginiana), Emory’s sedge (Carex emoryi), creeping spikerush (Eleocharis montevidensis), beaked spikerush (Eleocharis rostellata), scouringrush horsetail (Equisetum hyemale), white star sedge (Rhynchospora colorata), Cherokee sedge (Carex cherokeensis), purpletop tridens (Triden flavus), Texas blue grass (Poa arachnifera), Leavenworth’s sedge (Carex leavenworthii), stream sedge (Carex blanda), creek sedge (Carex amphibola), inland sea oats (Chasmanthium latifolium), Turk’s cap (Malvaviscus arboreus), roughleaf dogwood (Cornus drummondii), and black willow (Salix nigra). Jute matting was placed along the steeper banks to reduce erosion during the planting and establishing of the vegetation. Jute matting is biodegradable and over time will deteriorate.

Erosion Pins

Erosion pins were also placed at each cross section along both banks at the bankfull depth, 2 feet above the bankfull depth, and 4 feet above the bankfull depth. The erosion pins were approximately 3 foot long pieces of rebar that was pounded perpendicular into the stream bank. The top 6 inches remained above the ground and were painted florescent orange. Quarterly the erosion pins will be measured to determine the rate of erosion occurring along the stream bank.

 

Managing Invasives

TWRI worked with Texas Parks and Wildlife Department and the Guadalupe-Blanco River Authority to receive authorization to spray invasive elephant ear. On July 13, 2018 the TWRI team sprayed for elephant ears within the project using 1% Clearcast (Amazamox) and 0.8% Dyne-Amic solution.

 

Quarterly Measurements

The first quarterly erosion pin measurements were collected on July 13, 2018. 

Nathan measuring an erosion pin, which will be used in calculating the rate of erosion for the bank.