Weber River Flood Damage Assessment - Riverdale City

Riverdale City 2011 Flood Assessment October 13, 2011
Wetlands
Adjacent to the Weber River, RiverRestoration identified three emergent wetlands. One wetland
appears to be healthy and is located approximately 825 feet upstream of the Creekside Trail on the
Parkway. This wetland has a robust diversity of species and appears to have adequate flow and
oxygenation. The other two emergent wetlands have the potential to provide invaluable habitat and
improve water quality but are in need of enhancement.
The smallest and most downstream wetland is located adjacent to the North Trail Head. This wetland
appears to be the associated with stormwater runoff from the adjacent area. This wetland drains under
the Weber River Pathway just upstream of the Parker Rd. underpass. There is an abundance of algae
and trash present in the wetland (Figure 12). This wetland may have insufficient flow to provide
adequate oxygenation. The garbage should be removed and the mechanical drainage system should be
inspected to ensure there is adequate flow through the wetland.
Figure 12-North Trailhead Wetland
The second emergent wetland is located approximately 550 ft upstream on the Parkway from the Great
Salt Lake Brine Shrimp warehouse. This wetland appears to be a historic meander (or oxbow) that has
been isolated from the river due to the trail construction (Figure 13). This wetland is completely
covered with algae which reduces the amount of available oxygen. It is likely that this wetland is
anoxic (lacking oxygen) below the surface. Additionally there is a substantial amount of concrete
rubble dumped on the sides of the wetland. This concrete may have been placed there to protect the
bank from erosion when this was an active channel. RiverRestoraion recommends reconnecting this
wetland to the river with small culverts under the Parkway to improve its hydraulics as well as allow it
to provide some level of backwater storage during flashy flood events. This wetland is unique within
Riverdale City and has the potential to provide critical ecosystem functions as well as excellent
educational (interpretive) opportunities. Removal of the concrete would also provide aesthetic benefits
to the community.
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