Identifying Sediment Transport Potential and Velocity Profiles in the Carmel River Using an ADP
Abstract
The Carmel River runs 58 km from the Santa Lucia Mountains through the Carmel Valley, eventually stopping at a lagoon on Carmel River State Beach. During the winter months, the river breaches through the lagoon, allowing water to freely flow between the river and Carmel Bay. Sediment transport, in part owing to turbulent river discharge and in part owing to ocean forcing (tides and waves), contributes heavily to whether the lagoon is open or closed: when there are low flow conditions, waves and tides can decrease flow rates in the breach, allowing sediment to settle. The sediment budget is expected to be a closed system, owing to the rocky headlands and long-term stability (no yearly regression or transgression) of the shoreline. However, it is currently unknown 1) how velocity profiles evolve during breaching phases, and 2) how much sediment moves during such an event. The hypothesis is that the breach mouth can completely disappear and re-emerge over a single breach-closure cycle. This study uses the RiverSurveyor M9 acoustic Doppler profiler to measure outflow discharge and GPS surveys to quantify elevation changes. A velocity profile can be built that would estimate the sediment transport potential within the breach. The information obtained will help identify and better understand the velocity thresholds that contribute to breaching seasons as well as estimates of sediment transport rates during breaching, which are currently unknown.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2020
- Accession Number
- AD1127009
Entities
People
- Tyonna N Mcpherson
Organizations
- Naval Postgraduate School