Upper Mojave River Narrows
The Upper Mojave River Narrows is a geomorphic constriction within the Mojave River system where subsurface flow is forced to the surface by impermeable bedrock. It marks a transition zone as the river enters the northern Victorville Basin.
GEOLOGIC SETTING
The Narrows is formed by resistant, low permeability rock that restricts subsurface movement of water. As groundwater moving through alluvial sediments encounters this impermeable formation, it is forced upward to the surface.HYDROLOGIC FUNCTION
In much of its course, the Mojave River flows below the surface through permeable sands and gravels. At the Upper Narrows, however, the presence of impermeable rock creates a natural barrier that causes water to emerge as surface flow.This process produces one of the few reliable surface expressions of the Mojave River, even during otherwise dry conditions.
SYSTEM ROLE
The Upper Narrows serves as a control point in the river system, concentrating flow and directing it into the northern portion of the Victorville Basin. It represents a shift from dispersed subsurface flow to a more defined surface channel.SIGNIFICANCE
The Upper Mojave River Narrows is an important hydrologic feature that illustrates the interaction between geology and water movement in desert environments. It demonstrates how subsurface flow can be controlled and redirected by bedrock structure, producing localized surface flow within an otherwise intermittent river system.< Previous <> Next >
