22. Changing Elevations. No lot owner shall excavate or extract earth for any business purpose, nor raise the grade of any lot or lots above the grade established or to be established by the Developer without the written consent of the Developer. No elevation changes shall be permitted which materially affect surface grade or drainage of adjacent lots. Each lot owner is responsible to use due care to avoid interfering with the natural course of surface water in a fashion which would alter its natural flow across other lots or lands outside the Development.