INTERA Environmental Consultants, a combination of the environmental division of INTERCOMP Resource Development Engineering of Houston, Texas and ERA Sciences of Alberta, Canada. Initially, INTERA focused on providing air quality services, ranging from airborne and ground level measurements to detailed computer analysis of the results and prediction of future air quality changes. In the mid 1970s, the company began to apply INTERCOMP`s sophisticated petroleum reservoir engineering technology to the area of groundwater flow and transport. Under contract to the United States Geological Survey, INTERA developed the first groundwater code to couple flow, energy transport, and contaminant transport in three dimensions, accounting for density and viscosity effects.