Aquatic Vegetation Restoration
It has been documented over the past decade that the native aquatic vegetation plays a key role in supporting the native fish assemblages including the fountain darter. To minimize and mitigate the impacts of incidental take from low-flow events by providing better habitat conditions for the ecological community, the City of New Braunfels will undertake a program of native aquatic vegetation restoration within key, sustainable reaches of the Comal River by planting native vegetation in unoccupied areas and in areas previously occupied by non-native aquatic vegetation, with the latter preceded by non-native vegetation removal.
Two-dimensional hydraulic models will be used to evaluate the potential for success of the native vegetation restoration. This evaluation will consider the depth, velocity, and substrate conditions present in the proposed areas along with what non-native vegetation is thriving in these areas. In areas that are bare of vegetation, the reason vegetation is absent (e.g., recent flood scour, or unsuitable depth, velocity or substrate conditions) will be evaluated prior to restoration. Following an evaluation of the physical habitat model, an evaluation of water quality conditions will also be conducted. In particular, the CO2 need of the native aquatic plant being considered for establishment and the CO2 concentrations in the water column under varying flow conditions at the proposed restoration locations will be evaluated.
Additionally, restoration will involve acquiring local, disease- and pathogen-free plant material. The material will be removed from adjacent habitat or propagated off-site using plant material removed from the Comal System. Alternatively, it may be purchased from vendors who meet locally and disease free criteria. When non-native species are removed, they will be disposed of properly.
The focus of native vegetation restoration will be on Landa Lake downstream of Spring Run 3 but above the New Channel ISGS weir and on the portions of the Old Channel bordered on both sides by the City of New Braunfels’ property, including the Old Channel ERPA. Restoration efforts will also include establishing additional Cabomba along the eastern shoreline of Landa Lake and along the New Braunfels’ golf course property to create valuable fountain darter habitat.