Sediment Removal
The City of San Marcos will remove sediment from the river bottom at various locations from City Park to IH-35. These areas include but are not limited to reaches of the river in City Park, Veramendi Park, Bicentennial Park, Rio Vista Park and Ramon Lucio Park. Sediment has accumulated at these locations due to the installation of flood control dams, urbanization and natural processes. These accumulations have altered the river’s morphology and natural flow patterns. In addition, deposition of sediment on or around Texas wild-rice strands causes direct mortality by smothering or burying strands.
To minimize and mitigate the impacts of incidental take from recreation and pumping during low flow periods, the City of San Marcos will remove sediment from key areas of Texas wild-rice habitat below Sewell Park.
Hydrosuction will be used to remove accumulations of sediment. The silt will be vacuumed using a hose that has screen to prevent suctioning biota greater than 0.25 inch in diameter. The divers doing hydrosuctioning will take the following measures to minimize loss/harm of biota in the area. Divers will be trained to recognize all stages of listed species from larval to adult. The nozzle of the vacuum will be kept down in the soil and not allowed to be suctioned will keep divers away from the stands of wild-rice. An observer will be on the bank to monitor the effluent for presence of listed species and all other biota, as well as for the safety of the diver.
Sediment samples will be sent to TCEQ for contaminant testing per TCEQ requirements.