The degree of property protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on occasion. Flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside the regulated areas, or development permitted within such areas, will be free from flood damage. This chapter shall not create liability on the part of the city of Aberdeen or any officer or employee of the city for any damage to property or habitat that results from reliance on this chapter or any administrative decision lawfully made hereunder.