The performance standards and design criteria set forth herein establish minimum requirements which must be implemented with good engineering practice and workmanship. Use of the requirements contained herein shall not constitute a representation, guarantee or warranty of any kind by the city, or its officers and employees, nor shall approval of a stormwater management plan imply that the land uses permitted will be free from damages caused by stormwater runoff. The requirements of this Article were established to consider historical records of average rainfall and engineering and scientific methods. However, larger storms may occur or stormwater run-off heights may be increased by manmade or natural causes. The provisions of the Article, therefore, shall not be deemed to create liability on the part of the city or any officer or employee thereof with respect to any legislative or administrative decision lawfully made hereunder.