Entrenched meanders are the result of river meandering on a floodplain that becomes further incised due to base level changes or tectonic uplift. Several factors such as erosion, sedimentation, tectonic activities, and human interventions converge to shape these meanders.
Entrenched meanders begin as meanders on a floodplain; either the base level lowers or tectonic events cause uplift, leading to further incision, which deepens the meanders. Meandering occurs when water scours the outer bend of a river channel, depositing sediment on the inner bend. This is influenced by multiple geographical and geological factors, including topography, tectonics, and sediment load.
For instance, phase changes in a region, such as a rapid drop of the seafloor due to tectonic weight, can dramatically impact river flow and sediment deposition patterns. Similarly, the erosion and deposition of sediment as a river flows away from its source affects its meandering patterns. Over time, human intervention, such as the construction of levees and canals to manage water resources, can also alter river morphology and influence meanders.
In conclusion, entrenched meanders are a dynamic geomorphological feature resulting from interactions between water flow, sediment transfer, tectonic activities, and human modifications to the landscape.