F1 and F2 are actually districts used for planning purposes found in Sonoma County Code Ch. 26 Sections 56 and 58. The F1 district mostly aligns with the FEMA floodway and county code states "… no new permanent structure nor structure intended for human occupancy shall be permitted within the floodway." The F2 district applies to properties which lie within the one hundred (100) year flood hazard area as shown on the most recent FEMA maps. Structures proposed in the F2 shall be constructed in accordance with the provisions of Chapter 7B of the Sonoma County Code. Where, in the opinion of the planning director, or other decision-making body, topographic data, engineering studies or other studies are needed to determine the effects of flooding on a proposed structure, or the effect of the structure on the floodway, the applicant may be required to submit such data or studies prepared by competent engineers or other technicians. Within the Laguna de Santa Rosa, a “zero net fill” policy shall be enforced whereby no fill should be placed in the Laguna unless an engineering analysis demonstrates that no reduction in flood storage capacity would result from the placement of fill.