Lateral erosion of banks is a defining characteristic to any braided stream like the Platte. As water moves downstream, banks are transformed as water tends to spread out over the broad, shallow valley of the Platte River. Over the course of a year, our camera unexpectedly observed this happening at a camera location owned and managed by the Platte River Recovery Implementation Program.
The camera was placed downstream of the J-2 power plant, owned and operated by the Central Public Power District, used to generate power and divert water for purposes of irrigation. The location was an ideal position, as PRRIP began work on several restoration projects. Off the channel, they had constructing piping plover and least tern habitats and, in-the-channel, they began a sediment augmentation project which aimed to move sand and sediment from nearby locations into the Platte’s south channel, which was later described as “a sediment hungry river.”
Sediment starved flows cause the river channel to cut deeper into the stream bed altering the central nature of a braided stream. Without proper sediment transport, a shallow stream with many channels can turn into a stream that has fewer, deeper channels. This interrupts the river’s usefulness to wildlife species that need shallow channels and bare or partial submerged sandbars for nesting and roosting.
After a year in the field, we realized that the south bank was eroding, something we had not predicted or accommodated for. Approximately 15 feet of the bank had eroded; our camera was less than a foot from falling into the river at its closest. Following a slightly hurried schedule, we scouted a new location and relocated our camera with probably only a week or two to spare.
PRRIP, in order to curb the continued erosion downstream, began a project in which they moved sediment from a nearby lake into the channel and mechanically spread it across the stream bed, a process we hope to observe over time with newly placed camera.