The function E ( t ) = 3818 77.8 t gives the surface elevation (in feet above sea level) of Lake Powell t years after 1997. Interpret the Slope in this situation. The surface elevation of Lake Powell is Select an answer at a rate of Select an answer Interpret the Vertical Intercept in this situation. In the year , the surface elevation of Lake Powell was feet above sea level. This function accurately models the surface elevation of Lake Powell from 1997 to 2003. Determine the practical range of this linear function. E ( t ) feet above sea level