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Habitat Conservation Plan

Texas State University is contracted through the Edwards Aquifer Habitat Conservation Plan to improve and expand Texas wild rice habitat in the San Marcos River. We remove non-native species of aquatic vegetation and then re-plant native species such as Texas wild rice. Non-native plants are removed by hand and collected in nets and are then taken to a site on the Texas State University campus and composted. Native aquatic plants are grown at Texas State University and at the San Marcos Aquatic Resources Center before being planted in the river. Our efforts have contributed to a 53% increase in Texas wild rice distribution as of 2015.

Vegetation Mapping

We continually monitor Texas wild rice expansion in areas that we have worked.

Texas State University Dredging Methods

Texas State utilizes a Piranha Mini Dredge PS-135 model to suction fine sediment from the river (Fig 1). Piranha Mini Dredge is equipped with a 13.5 hp Honda motor and agitator using a 3 inch discharge size hose. Approximate excavation rate runs 20-30 cuyd/hr. Prior to dredging, an area is denuded of aquatic vegetation with native species transplanted to another location and non-native species removed and transported to the Texas State composting site.

Figure 1

Figure 1

The dredge is equipped with a strain on the suction head to prevent large material/debris to pass through the pump (Fig 2). Figure 2 illustrate how fine sediment is loosened by the agitator and then suctioned up through the pump.

Figure 2

Figure 2

 

Figure 2

The dredged sediment is contained in a geotextile dewatering tube or placed into a catchment pit area (Fig 3).

Figure 3

Figure 3

The dewatering tube retains the dredged sediment while slowing releasing filtrated water. Once a dewatering tube is filled to approximately 85% capacity, the bag will be left to drain before the sediment is transported to the Texas State Composting Facility.

Figure 4

Figure 4

How can you get involved?

Habitat restoration is a tough job and volunteers are always appreciated. If you are interested in volunteering with us please contact Jacob Bilbo at (512) 245-3553 or email at jnb67@txstate.edu.