In all flood hazard areas defined in Section 24.50.050, the following requirements apply:

1. A.   Permits.  All permit applications will be reviewed to determine whether proposed development and building sites comply with the provisions of this Chapter and will be reasonably safe from flooding.  A development or building permit must be obtained before construction or development begins within any flood hazard area.  The development or building permit is required for all structures, including manufactured homes, and for all other development, as defined in this Chapter, including fill.  Such applications for permits must include the following information:
   1. 1. Boundary of flood hazard areas.
   2. 2. Boundaries of the high hazard area, top of bank, 50-foot setback from top of bank, Ordinary High Water Mark, and the PICM Riparian Buffer Zone, as applicable.
   3. 3. The base flood elevation and design flood elevation.
   4. 4. Elevation of lowest floor, including basement, for all structures and floodproofed elevations for nonresidential structures.
   5. 5. When required by the Floodplain Administrator, documentation necessary to verify substantial improvement or substantial damage.
   6. 6. Elevation of lowest point of bridge structures.
   7. 7. Existing and proposed topography of the site taken at a contour interval (normally 1 foot) sufficiently detailed to define the topography over the entire site and adjacent watercourses subject to flooding.  Ninety percent of the contours must be plotted within 1 contour interval of the true location.
   8. 8. All necessary permits obtained from the federal and state governmental agencies from which prior approval is required.
   9. 9. When required by the Floodplain Administrator, documentation prepared by a registered design professional that demonstrates compliance with the regulations of this Chapter.
   10. 10. When required by the Floodplain Administrator and where elevation data are not available either through the Flood Insurance Study or from another authoritative source (see Subsection 24.50.050 I.), documentation prepared by a registered design professional that demonstrates the proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of any available hydrological data, drainage basin hydrology, historical data, high water marks, photographs of past flooding, etc., where available.  Failure to elevate at least 2 feet above grade in these zones may result in higher insurance rates.
2. B.   Elevation reference.  The survey reference datum for finished lowest floor including basement, floodproofed elevations, and finished site grades must be either the North American Vertical Datum of 1988 or City of Portland datum, whichever is appropriate.  When approved by the City Engineer, a local onsite survey reference datum may be adopted for FIRM Zones A and Unidentified Watercourse Flood Zones.  The survey reference datum must be indicated on all relevant plan and section drawings, calculations, and the certified FEMA Elevation Certificate.
3. C.   Certification of elevations, floodproofing, flood storage compensation, and the Pre-Implementation Compliance Measures of Subsection 24.50.060 H.
   1. 1.  All elevations specified below must be certified on a FEMA (FIA) Elevation Certificate by a licensed surveyor or engineer secured by the permittee and made part of the permit records.
      1. a.  During construction elevation of the lowest floor, including basement, of all new or substantially improved structures upon placement of the lowest floor but prior to further vertical construction;
      2. b.  As-built finished elevation of lowest floor including basement of all new or substantially improved structures;
      3. c.  As‑built finished floodproofed elevation of all new or substantially improved nonresidential structures;
      4. d.  As‑graded finished elevation of lowest grade within 25 feet of structures; and
      5. e.  As‑graded finished elevation of lowest crawl space grade, as applicable.
   2. 2.  All floodproofing materials and methods for nonresidential structures must be certified by a licensed professional engineer or architect as meeting the criteria in Subsection 24.50.060 F.7.
   3. 3.  When required by the Floodplain Administrator, documentation prepared by a registered design professional necessary to demonstrate compliance with the flood storage compensation requirements and Pre-Implementation Compliance Measures of this Chapter must be submitted and approved prior to final inspection approval.
4. D.   Floodway.  Encroachments into the floodway by development and structures defined in Section 24.50.030 are prohibited unless it is demonstrated by technical analysis from a registered engineer that the development will result in no increase in the base flood elevation.  In areas where a regulatory floodway has not been designated, no new construction, substantial improvement, or other development (including fill) will be permitted within Zone AE, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than 1 foot at any point within the flood hazard areas regulated by the City.  Technical analysis will be reviewed and approved by the Sewage System Administrator.  However, the minimum width of the floodway may not be less than 15 feet, unless otherwise approved by the Sewage System Administrator.
5. E.   New Technical Data and Notifications of Other Entities.  Portland Permitting & Development will:
   1. 1.  City boundary alterations.  Notify the Federal Insurance Administration in writing whenever the boundaries of the City have been modified by annexation or the City has otherwise assumed authority or no longer has authority to adopt and enforce floodplain management regulations for a particular area, to ensure that all Flood Hazard Boundary Maps (FHBM) and Flood Insurance Rate Maps (FIRM) accurately represent the City’s boundaries.  The Bureau will include within such notification a copy of a map of the City suitable for reproduction, clearly delineating the new corporate limits or new area for which the City has assumed or relinquished floodplain management regulatory authority.
   2. 2.  Watercourse alterations.  Notify adjacent communities, the Department of Land Conservation and Development, and other appropriate state and federal agencies, prior to any alteration or relocation of a watercourse as identified in the Flood Insurance Study and Flood Insurance Rate Map, and submit evidence of such notification to the Federal Insurance Administration.  The applicant must provide this notification to the Federal Insurance Administration as a Conditional Letter of Map Revision (CLOMR) along with either:
      1. a.  A proposed maintenance plan to ensure the flood-carrying capacity within the altered or relocated portion of the watercourse will be maintained; or
      2. b.  Certification by a registered professional engineer that the project has been designed to retain its flood carrying capacity without periodic maintenance.
   3. 3.  New technical data.  Notify the Federal Insurance Administration of changes in the special flood hazard area based on new or improved scientific data that more accurately reflect the flood hazard boundaries and water surface elevations.  The City will apply to FEMA for a CLOMR prior to permit issuance for:
      1. a.  Proposed floodway encroachments that will increase the base flood elevation; and
      2. b.  Proposed development that will increase the base flood elevation by more than 1 foot in areas where FEMA has provided base flood elevations but no floodway (see Subsection 24.50.060 D.)
   4. 4.  Letter of Map Revision.  Require the applicant to notify FEMA within six months of project completion when FEMA has issued a CLOMR for the project.  This notification to FEMA must be provided as a Letter of Map Revision (LOMR).
6. F.    Flood hazard areas.
   1. 1. General.  All new construction and substantial improvements must be anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrostatic and hydrodynamic loads and effects of buoyancy.
   2. 2. Residential construction.
      1. a.  New construction and substantial improvement of any residential structure must have the lowest floor, including basement, elevated to or above the flood protection elevation.  Floodproofing of “lowest floor” space is not permitted.
      2. b.  Enclosed areas below the lowest floor that are subject to flooding are prohibited unless they are used solely for parking of vehicles, building access, or limited storage and are designed to automatically equalize hydrostatic flood forces on exterior walls by allowing the entry and exit of floodwaters.  Designs for meeting this requirement must meet or exceed the following minimum criteria:
         1. (1)  There must be a minimum of two openings on different sides of each enclosed area;
         2. (2)  The total net area of all openings for each enclosed area must not be less than one square inch for every square foot of enclosed area subject to flooding or must be certified by a registered design professional;
         3. (3)  The bottom of all openings may be no higher than 1 foot above grade;
         4. (4)  Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters; and
         5. (5)  An agreement approved by the Floodplain Administrator not to convert the use of the enclosed area must be recorded against the property deed when required by the Floodplain Administrator.
      3. c.  Fill required to elevate the lowest floor to the flood protection level must comply with Chapter 24.70.  Fill selection and placement must recognize the effects of inundation from floodwaters on slope stability, fill settlement, and scour.  The minimum elevation at the top of the fill slope must be at or above the design flood elevation.  Minimum distance from any point of the building perimeter to the top of the fill slope must be at least 25 feet or twice the depth of fill at that point, whichever is the greater distance.
   3. 3. Subdivision proposals.
      1. a.  All subdivision proposals must be consistent with the need to minimize flood damage;
      2. b.  All subdivision proposals must have public utilities and facilities such as sewer, gas, electrical, and water systems located and constructed to minimize flood damage;
      3. c.  All subdivision proposals must have adequate drainage provided to reduce exposure to flood damage; and,
      4. d.  Where base flood elevation data have not been provided or are not available from another authoritative source, it must be generated for subdivision proposals and other proposed developments that contain at least 50 lots or 5 acres.
   4. 4. Nonresidential construction.  New construction and substantial improvement of any commercial, industrial, or other nonresidential structure must either have the lowest floor, including basement, elevated to the level of the flood protection elevation, or, together with attendant utility and sanitary facilities, must:
      1. a.  Be floodproofed so that below the flood protection elevation the structure is watertight with walls substantially impermeable to the passage of water;
      2. b.  Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and
      3. c.  Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this Subsection based on the professional engineer’s or architect’s development or review of the structural design, specifications, and plans.  Such certifications must be provided to Portland Permitting & Development.
      4. d.  Nonresidential structures that are elevated, but not floodproofed, must meet the same standards for space below the lowest floor as described for residential structures.
      5. e.  Applicants floodproofing nonresidential buildings will be notified that flood insurance premiums will be based on rates as if the building is 1 foot below the floodproofed level (i.e., a building constructed to the base flood level will be rated as 1 foot below that level).
   5. 5. Manufactured homes.  All manufactured homes to be placed or substantially improved within the flood hazard area must be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the flood protection elevation; securely anchored to prevent flotation, collapse, or lateral movement; and installed using methods and practices that minimize flood damage.  The construction must conform to the requirements of Subsection 24.50.060 F.2.  Anchoring methods may include, but are not limited to, use of over‑the‑top or frame ties to ground anchors (Refer to FEMA’s "Manufactured Home Installation in Flood Hazard Areas” guidebook for additional techniques).
   6. 6. Utilities.  All new and replacement water supply and sanitary sewage systems must be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the sanitary sewage systems into floodwaters.  On‑site waste disposal systems must be located to avoid impairment to them or contamination from them during flooding.
   7. 7. Construction materials and methods.  All new construction and substantial improvements must be constructed with materials and utility equipment resistant to flood damage, using methods and practices that minimize flood damage.  Electrical, heating, ventilation, plumbing, and air‑conditioning equipment and other service facilities must be protected to or above the flood protection elevation.
   8. 8. Tanks.   
      1. a.  Underground tanks must be anchored to prevent flotation, collapse, and lateral movement under conditions of the design flood.
      2. b.  Above-ground tanks must be installed at or above the flood protection elevation or be anchored to prevent flotation, collapse, and lateral movement under conditions of the design flood.
   9. 9. Uncontained hazardous materials as referred to in Section 101 (14) of the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (42 U.S. Section 9601 et seq.) (CERCLA), Section 502 (13) of the Clean Water Act and any other substances so designated by the City Administrator are prohibited in flood hazard areas.
   10. 10. Johnson Creek Flood Risk Areas - Special Provisions.  In addition to other requirements of this Chapter, the following requirements apply within the Johnson Creek Flood Risk Area, as established in Chapter 33.537:
       1. a.  Reduction in flooding capacity prohibited.  Structures, fill, or other development are only allowed in the Johnson Creek Flood Risk Area when they are designed so that there will be no significant reduction in the storage capacity of the floodway and flood fringe and there will be no significant impediment to the passage of floodwaters.
       2. b.  Exceptions to the applicability of Subsection 24.50.060 F.10.a.:
          1. (1)  One-story, detached accessory buildings used as tool and storage sheds, playhouses or similar uses, provided the floor area does not exceed 120 square feet.
          2. (2)  Parking garages accessory to one- and two-family structures, provided the floor area does not exceed 300 square feet.
          3. (3)  Fences that do not prevent the flow of water.
       3. c.  Buildings designed to meet all of the following criteria will be presumed to comply with Subsection 24.50.060 F.10.:
          1. (1)  At least 50 percent of perimeter walls located at, or below, the base flood elevation will remain open and unenclosed;
          2. (2)  At least 25 percent of each perimeter wall located at, or below, the base flood elevation will remain open and unenclosed; and
          3. (3)  The footprint of all portions of the building located at, or below, the base flood elevation may not exceed 15 percent of the footprint of the building located above the base flood elevation.
   11. 11. AH/AO Zone Drainage. Adequate drainage paths must be provided around structures on slopes to guide floodwaters around and away from proposed structures.
7. G.   Compensatory excavation or removal required.
   1. 1. The following compensatory excavation or removal regulations apply at the time of a building or development permit application.
   2. The provisions of this Subsection apply exclusively to the compensatory excavation and removal requirements of Subsection 24.50.060 G.
      1. a. Applications for building or development permits will be processed based on the compensatory excavation or removal regulations in effect on the date a complete permit application is filed with the City. For the purposes of this Section, a complete building or development permit application contains the information necessary to determine whether the proposal conforms with all applicable regulations and development standards.
      2. b. Exceptions to the application of Subsection 24.50.060 G.1.a.:
         1. (1) An application for a building or development permit for development approved by an Environmental Review, Greenway Review, South Waterfront Greenway Review, Land Division, Conditional Use Master Plan, Planned Development Review, or River Review land use decision that has not expired may be processed based on the compensatory excavation or removal regulations in effect on the date the land use application was filed with the City, as specified in Chapter 33.700, provided a building or development permit is issued before expiration of the final land use decision.
         2. (2) An application for a building or development permit for development approved by a Central City Master Plan land use decision may be processed based on the compensatory excavation or removal regulations in effect on the date the complete land use application was filed with the City, as specified in Chapter 33.700, provided the building or development permit is issued no later than 10 years after the date of the final land use decision.
      3. c. A revision to a building or development permit application will be processed based on the compensatory excavation or removal regulations in effect when the original complete permit application was filed if the volume of floodwater displaced by fill or structure placed within the special flood hazard area at or below the base flood elevation is not increased by more than 10 percent relative to the volume indicated on the original approved permit application.
      4. d. For the purposes of Subsection 24.50.060 G., structure means anything that is built or constructed, an edifice or building of any kind, or any piece of work artificially built up or composed of parts joined together in some definite manner.
   3. 2. In flood hazard areas regulated by the City: The application must provide for a compensatory volume, consisting of either the excavation of soil or rock or the removal of permanent structures that displace floodwater, or both, to compensate for the loss of flood storage volume as described in the Subsections below.  The compensatory volume must be located within the same flood hazard area, identified in Subsections 24.50.050 A. through J., as the one in which the fill or structure will cause the loss of flood storage.
      1. a. Columbia River Flood Zones, Willamette River Central and South Reach Flood Zones, and Fanno Creek Flood Zones: The volume of floodwater displaced by fill or structures placed within the special flood hazard area at or below the base flood elevation requires a compensatory volume below the base flood elevation as follows:
         1. (1) For fill or structure placed within the high hazard area, the compensatory volume must be equal to or greater than twice the displaced volume (a ratio of at least 2 to 1) and must be located within the high hazard area.
         2. (2) For fill or structure placed landward of the high hazard area and within a 50-foot setback measured landward from top of bank, the compensatory volume must be equal to or greater than one and a half times the displaced volume (a ratio of at least 1.5 to 1) and must be located within the high hazard area, landward of the high hazard area and within the 50-foot setback, or both.
         3. (3) For fill or structure placed landward of the 50-foot setback from top of bank, the compensatory volume must be equal to or greater than the displaced volume (a ratio of at least 1 to 1).
         4. (4) Exceptions to the application of Subsections 24.50.060 G.2.a.(1) – (3):
            1. (a) Subsections 24.50.060 G.2.a.(1) – (3) do not apply to areas with Heavy Industrial (IH), General Industrial 2 (IG2), or General Employment 2 (EG2) zoning.
            2. (b) Subsections 24.50.060 G.2.a.(1) – (3) do not apply to the portion of the South Waterfront Subdistrict of the Central City Plan District north of Willamette River mile 14.6 as described in the Flood Insurance Study.
            3. (c) Subsections 24.50.060 G.2.a.(1) – (3) do not apply to the portion of the University District/South Downtown Subdistrict of the Central City Plan District south of Willamette River mile 13.4 as described in the Flood Insurance Study.
      2. b. Multnomah Drainage District No. 1, Peninsula Drainage District No. 1 and Peninsula Drainage District No. 2 Flood Zones, and Unidentified Watercourse Flood Zones: The volume of floodwater displaced by fill placed within the special flood hazard area at or below the base flood elevation requires a compensatory volume below the base flood elevation equal to or greater than the displaced volume (a ratio of at least 1 to 1).
      3. c. February 1996 Flood Inundation Areas: The volume of floodwater displaced by fill placed within the February 1996 Flood Inundation Area requires a compensatory volume below the February 1996 Flood Inundation Elevation as follows:
         1. (1) In areas outside of the special flood hazard area, the compensatory volume must be equal to or greater than the displaced volume (a ratio of at least 1 to 1).
         2. (2) In areas within both the special flood hazard area and the February 1996 Flood Inundation Area, where the February 1996 Flood Inundation Elevation is greater than the base flood elevation, the compensatory volume must be equal to or greater than the displaced volume between the February 1996 Flood Inundation Elevation and the base flood elevation (a ratio of at least 1 to 1). Compensatory excavation requirements at and below the base flood elevation are described in Subsections 24.50.060 G.2.a. and b.
   4. 3. Excavation of soil or rock or the removal of permanent structures from an area may not be counted as compensatory volume if the area will be filled with water in non-storm winter or spring conditions.
   5. 4. Compensatory excavation and removal areas must be designed to freely drain to the source of flooding to the extent practicable to avoid stranding fish.
   6. 5. Temporary fills permitted during construction must be removed prior to final inspection approval of the permit.
   7. 6. Mitigation bank credits may be substituted for compensatory excavation or removal of permanent structures, provided the mitigation bank has been approved by the City and the mitigation bank is located within the same flood hazard area, identified in Subsections 24.50.060 A. through J., as the development and satisfies the requirements of Subsections 24.50.060 G.2.a. through c.
8. H. FEMA Pre-Implementation Compliance Measures (PICM) required.  These regulations prohibit a net loss in three proxies for natural floodplain function: flood storage, water quality through stormwater management, and vegetated habitat through tree replacement requirements.
   1. 1.   The following PICM regulations apply at the time of a building or development permit application. 
      
      The provisions of this Subsection apply exclusively to the PICM regulations of Subsection 24.50.060 H.
      1. a. Applications for building or development permits will be processed based on the PICM regulations in effect on the date a complete permit application is filed with the City.  For the purposes of this Subsection, a complete building or development permit application contains the information necessary for the City to determine whether the proposal conforms with all applicable regulations and development standards.
      2. b. Exceptions to the application of Subsection 24.50.060 H.1.a.:
         1. (1)  An application for a building or development permit for development approved by an Environmental Review, Greenway Review, Land Division, Conditional Use Master Plan, Planned Development Review, or River Review land use decision that has not expired may be processed based on the PICM regulations in effect on the date the land use application was filed with the City, as specified in Chapter 33.700, provided a building or development permit is issued before expiration of the final land use decision.
         2. (2) An application for a building or development permit for development approved by a Central City Master Plan land use decision may be processed based on the PICM regulations in effect on the date the complete land use application was filed with the City, as specified in Chapter 33.700, provided the building or development permit is issued no later than 10 years after the date of the final land use decision.
      3. c. A revision to a building or development permit application will be processed based on the PICM regulations in effect when the original complete permit application was filed if the volume of floodwater displaced by fill or structure placed within the special flood hazard area at or below the base flood elevation is not increased by more than 10 percent relative to the volume indicated on the original approved permit application.
      4. d. For the purposes of Subsection 24.50.060 H., structure means anything that is built or constructed, an edifice or building of any kind, or any piece of work artificially built up or composed of parts joined together in some definite manner.
   2. 2.   Within the Crystal Springs Creek Flood Zones; Johnson Creek Flood Zones; Tryon Creek Flood Zones; Willamette River North Reach Flood Zones; and areas with Heavy Industrial (IH), General Industrial 2 (IG2), or General Employment 2 (EG2) zoning within the Columbia River, Willamette River Central and South Reach, and Fanno Creek Flood Zones:  The application must demonstrate compliance with the PICM requirements described below.
      1. a. Compensatory excavation or removal required.
         1. (1)  The application must provide for a compensatory volume, consisting of either the excavation of soil or rock or the removal of permanent structures that displace floodwater, or both, to compensate for the loss of flood storage volume as described in the Subsections below.  The compensatory volume must be located within the same flood hazard area, identified in Subsections 24.50.050 A. through J., as the one in which the fill or structure will cause the loss of flood storage.  In the Johnson Creek flood zones, the compensatory volume must be on the same site. The volume of floodwater displaced due to the placement of fill or structure within the special flood hazard area at or below the base flood elevation requires a compensatory volume below the base flood elevation that is hydrologically connected to the source of flooding as follows:
            1. (a)  The volume of floodwater displaced within the Floodway or PICM Riparian Buffer Zone requires a compensatory volume equal to or greater than twice the displaced volume (a ratio of at least 2 to 1) located within the floodway or the PICM Riparian Buffer Zone.
            2. (b)  The volume of floodwater displaced landward of the PICM Riparian Buffer Zone, requires a compensatory volume equal to or greater than one and a half times the displaced volume (a ratio of at least 1.5 to 1).
         2. (2)  Excavation of soil or rock or the removal of permanent structures from an area may not be counted as compensatory volume if the area will be filled with water in non-storm winter or spring conditions.
         3. (3)  Compensatory excavation and removal areas must be designed to freely drain to the source of flooding to the extent practicable to avoid stranding fish.
         4. (4)  Temporary fills permitted during construction must be removed within one year of placement and prior to final inspection approval of the permit.
         5. (5)  Mitigation bank credits may be substituted for compensatory excavation or removal of permanent structures, provided the mitigation bank has been approved by the City and the mitigation bank is located within the same flood hazard area, identified in Subsections 24.50.060 A. through J., as the development and satisfies the requirements of Subsections 24.50.060 H.2.a.
      2. b. The application must provide for stormwater management in accordance with the requirements of the City of Portland Stormwater Management Manual.
      3. c. The application must provide for tree replacement within the special flood hazard area.  Removal of trees 6 inches in diameter at breast height (dbh) or larger must be replaced by trees planted within the special flood hazard area at the ratios described below:
         1. (1)  Within the Floodway and PICM Riparian Buffer Zone,
            1. (a)  Trees that are 6 inches dbh up to 20 inches dbh must be replaced at a ratio of three trees for each tree removed (a ratio of 3 to 1);
            2. (b)  Trees that are larger than 20 inches dbh and less than or equal to 39 inches dbh must be replaced at a ratio of five trees for each tree removed (a ratio of 5 to 1);
            3. (c)  Trees larger than 39 inches dbh must be replaced at a ratio of six trees for each tree removed (a ratio of 6 to 1).
         2. (2)  Landward of the PICM Riparian Buffer Zone,
            1. (a)  Trees that are 6 inches dbh up to 20 inches dbh must be replaced at a ratio of two trees for each tree removed (a ratio of 2 to 1);
            2. (b)  Trees that are larger than 20 inches dbh and less than or equal to 39 inches dbh must be replaced at a ratio of four trees for each tree removed (a ratio of 4 to 1);
            3. (c)  Trees larger than 39 inches dbh must be replaced at a ratio of five trees for each tree removed (a ratio of 5 to 1).
         3. (3)  Replacement trees must be no smaller than 1.5-inch caliper, identified as native in the Portland Plant List, and planted within the same flood hazard area, identified in Subsections 24.50.050 A. through J., as the one from which the trees are removed.
         4. (4)  Trees removed from the PICM Riparian Buffer Zone must be replaced with trees planted within the PICM Riparian Buffer Zone.
         5. (5)  Replacement trees required by this Subsection may also count towards satisfying tree replacement required by Title 11 or Title 33 provided the tree replacement meet the requirements therein.
      4. d. The application must provide for beneficial gain within the PICM Riparian Buffer Zone as described below.
         1. (1)  An area equal to or greater than five percent of the new development area within the PICM Riparian Buffer Zone must be planted with native herbaceous, shrub, or tree vegetation at the following minimum planting density: 10 plants per 50 square feet at a ratio of one tree, two shrubs, and seven groundcover plants.  Trees must be at least one-half inch in diameter, shrubs must be at least one gallon, and groundcover plants must be a minimum pot size of four inches.  The remaining area must be seeded with native grass seed.
         2. (2)  The planted area must be within the same flood hazard area, identified in Subsections 24.50.050 A. through J., as the development within the PICM Riparian Buffer Zone.
         3. (3)  An agreement approved by the Floodplain Administrator to preserve the planted area must be recorded against the property.
         4. (4)  Plantings required by this Subsection may also count towards satisfying plantings required by Title 11 and Title 33 provided the plantings meet the requirements therein. Plantings required as mitigation for an approved environmental land use review cannot count toward meeting this beneficial gain requirement.
         5. (5)  The requirements of Subsection 24.50.060 H.2.d. do not apply to functionally-dependent uses.
   3. 3.   Mitigation required to meet the no-net-loss requirements of Subsection 24.50.060 H.2. must be implemented within one year of any loss in the proxies for natural floodplain function to retain the mitigation ratios described in Subsection 24.50.060 H.2.  The mitigation required must be increased 25 percent for each additional year the corresponding mitigation is delayed and a permit revision will be required to document the additional mitigation measures.
   4. 4.   Prior to the issuance of any building or development permit, the applicant must:
      1. a. Demonstrate a legal right to implement proposed mitigation.
      2. b. Demonstrate financial assurances are in place for the long-term maintenance and monitoring of required mitigation.
      3. c. Submit a mitigation management plan that identifies the responsible site manager, stipulates activities allowed on site, and requires the posting of signage identifying the site as a mitigation area.
   5. 5.   Exemptions to Subsection 24.50.060 H.
      1. a. Projects approved under separate consultations under Section 4(d), 7, or 10 of the Endangered Species Act provided the consultation addresses project impacts within the special flood hazard area.
      2. b. Routine agricultural practices such as tilling, plowing, harvesting, soil amendments, and ditch cleaning that do not alter the ditch configuration, provided the spoils are removed from the flood hazard area or tilled into fields as a soil amendment.
      3. c. Routine silviculture practices that do not meet the definition of development, including harvesting of trees, provided root balls are left in place.
      4. d. Routine maintenance of landscaping that does not involve grading, excavation, or filling.
      5. e. Removal of dead, dying, or dangerous trees as allowed under Title 11.
      6. f. Pre-emptive removal of documented susceptible trees to manage the spread of invasive species.
      7. g. Replacement of non-native vegetation with native vegetation.
      8. h.  Normal maintenance or repair of structures, such as re-roofing or replacement of siding, provided there is no expansion of the structure footprint or the horizontal projection of the roof area.
      9. i. Alteration of building interiors, provided there is no expansion of the building footprint or the horizontal projection of the roof area.
      10. j. Normal street, sidewalk, below-ground utilities, and road maintenance, including filling potholes, repaving, and installing signs and traffic signals.  The work may not alter the use, elevation contours more than six inches above existing grade, or culverts.  The work may not expand the footprint of existing improvements.
      11. k. Normal maintenance of above-ground utilities and facilities, such as replacing downed power lines and utility poles, provided there is no net change in the footprint of existing improvements.
      12. l. Normal maintenance of a levee or other flood control facility prescribed in the operations and maintenance plan for the levee or flood control facility.  Normal maintenance does not include repair from flood damage, expansion of the prism, expansion of the face or toe, or addition of protection on the face or toe with rock or other armor.