Characterization of a fractured aquifer using the colloidal borescope

Quantifying and characterizing groundwater flow in fracture flow systems is a difficult task due to the complexity of these systems. The recently deve loped colloidal borescope is a useful instrument that can provide direct me asurements of flow velocity and direction from wells completed in fractures . The colloidal borescope was recently used in the Sandia Mountains near Al buquerque, New Mexico to supplement an ongoing investigation at a leaking u nderground storage tank site. Results from the field investigation using th e colloidal borescope showed that groundwater flow directions in the unfrac tured zones agreed with the regional groundwater flow directions. In fractu red zones, groundwater flow directions were in a direction corresponding to fracture trends that were different than the inferred potentiometric surfa ce. Groundwater velocities in the fractures were an order of magnitude high er than velocities observed in the unfractured flow zones. The resultant fl ow direction of the unfractured and fractured flow zones agreed with the ob served flow direction of a groundwater hydrocarbon plume.