15.24.160 Floodway location.
Located within areas of special flood hazard established in CEMC Section 15.24.060 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:
A. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment shall not result in any increase in flood levels during the occurrence of the base flood discharge.
B. Construction or reconstruction of residential structures is prohibited within designated floodways, except for:
1. Repairs, reconstruction, or improvements to a structure which do not increase the ground floor area; and
2. Repairs, reconstruction or improvements to a structure, the cost of which does not exceed fifty percent of the market value of the structure either:
a. Before the repair, reconstruction or repair is started, or
b. If the structure has been damaged, and is being restored, before the damage occurred. Any project for improvement of a structure to correct existing violations of state or local health, sanitary or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions, or to structures identified as historic places shall not be included in the fifty percent;
3. Substantially Damaged Residences in Floodway.
a. For all substantially damaged residential structures, other than farmhouses, located in a designated floodway, the floodplain administrator may make a written request that the Department of Ecology assess the risk of harm to life and property posed by the specific conditions of the floodway. Based on analysis of depth, velocity, flood-related erosion, channel migration, debris load potential, and flood warning capability, the Department of Ecology may exercise best professional judgment in recommending to the local permitting authority repair, replacement, or relocation of a substantially damaged structure consistent with WAC 173-158-076. The property owner shall be responsible for submitting to the local government and the Department of Ecology any information necessary to complete the assessment. Without a favorable recommendation from the Department for the repair or replacement of a substantially damaged residential structure located in the regulatory floodway, no repair or replacement is allowed per WAC 173-158-070(1).
b. Before the repair, replacement, or reconstruction is started, all requirements of the NFIP, the state requirements adopted pursuant to Chapter 86.16 RCW, and all applicable local regulations must be satisfied. In addition, the following conditions must be met:
i. There is no potential safe building location for the replacement residential structure on the same property outside the regulatory floodway.
ii. A replacement residential structure is a residential structure built as a substitute for a legally existing residential structure of equivalent use and size.
iii. Repairs, reconstruction, or replacement of a residential structure shall not increase the total square footage of floodway encroachment.
iv. The elevation of the lowest floor of the substantially damaged or replacement residential structure is a minimum of one foot higher than the BFE.
v. New and replacement water supply systems are designed to eliminate or minimize infiltration of floodwater into the system.
vi. New and replacement sanitary sewerage systems are designed and located to eliminate or minimize infiltration of floodwater into the system and discharge from the system into the floodwaters.
vii. All other utilities and connections to public utilities are designed, constructed, and located to eliminate or minimize flood damage.
C. If subsection (A) of this section is satisfied or construction is allowed pursuant to subsection (B) of this section, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of CEMC Section 15.24.150, provisions for flood hazard reduction.