For purposes of this chapter:
DEVELOPED PARCEL: Means any parcel that has been altered from its natural conditions by grading, filling, or the construction of improvements or other impervious surfaces.
EQUIVALENT RESIDENTIAL UNIT OR ERU: Means the average amount of impervious surface, expressed in square feet, on developed single-family residential parcels in the City. One ERU equals three thousand four hundred (3,400) square feet of impervious surface.
IMPERVIOUS SURFACE: Means any hard surface, other than the natural surface, that prevents or retards the absorption of water into the soil, or that causes water to run off the surface in greater quantities or at greater rates of flow than the natural surface. (Ord. 17-40)