Exhibit 10 Western Resources logo John E. Hayes, Jr. Chairman of the Board August 14, 1998 Mr. David C. Wittig President & Chief Executive Officer Western Resources, Inc. 818 S. Kansas Avenue Topeka, KS 66612 Dear David, Reference is made to our letter agreement of April 27, 1995, and the supplemental benefit outlined in paragraph 3 thereof. The Company and you have agreed that you become eligible and shall fully vest in such supplemental benefit on May 1, 1999, and on or after such date you may, at your option, receive the full amount of such benefit in a lump sum. Sincerely, /s/ John