a. No Floodplain Development Permit Application shall be approved for any structure or parking area that encroaches on an Area of Special Flood Hazard unless:
i. The parking area is smaller than 5,000 square feet, or
ii. The structure is unoccupied and has an area of less than 1,000 square feet,
iii. The lowest finished floor elevation of the structure is elevated to or above the regulatory flood datum.
b. No encroachments, including fill, new construction, substantial improvements, or other development, shall be permitted within an Area of Special Flood Hazard unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels within the community during the occurrence of the base flood discharge. Such encroachment shall not cause an adverse effect on the Area of Special Flood Hazard or surrounding properties, and shall otherwise comply with the requirements of this section.
c. No fill material shall be used to elevate any structure in Zones A, A1-30, AE, AO, AH, AR, or A99, unless:
i. The fill material is compacted to not less than 95 percent of the maximum dry density conforming to Texas Department of Transportation Test Method Tex-114-E, "Laboratory Compaction Characteristics & Moisture-Density Relationship of Subgrade & Embankment Soil";
ii. The fill material is comprised of fine grained soils of low permeability, such as those classified as CH, CL, SC, or ML according to ASTM Standard D-2487, "Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)"; and
iii. The fill material is homogeneous and isotropic (specifically, that the soil is all of one material and the engineering properties are the same in all directions).
