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Dayton City Zoning Code

ARTICLE 14

400: Environmental Management

Sec. 14.401.1 Statutory Authorization

This Section is adopted under the authorization of the Legislature of the State of Texas in the Flood Control Insurance Act, Texas Water Code, Section 16.315, which has delegated the responsibility of local governmental units to adopt regulations designed to minimize flood losses.

Effective on: 5/20/2019

Sec. 14.401.2 Findings of Fact

  • Flood Hazard Areas. The flood hazard areas of the City are subject to periodic inundation, which may result in loss of life and property, health and safety hazards, disruption of commerce and governmental services, and extraordinary public expenditures for flood protection and relief, all of which adversely affect the public health, safety, and general welfare.
  • Creation of Losses. These flood losses are created by the cumulative effect of obstructions in floodplains, which cause an increase in flood heights and velocities, and by the occupancy of flood hazard areas by uses vulnerable to floods and hazardous to other lands because they are inadequately elevated, flood-proofed, or otherwise protected from flood damage.

    • Effective on: 5/20/2019

    Sec. 14.401.3 Statement of Purpose and Disclaimer

  • Purpose. It is the purpose of this Article to promote the public health, safety, and general welfare and to minimize public and private losses due to flood conditions in specific areas by provisions designed to:
    1. Life Safety. Protect human life and health;
    2. Expenses. Minimize expenditure of public money for costly flood control projects;
    3. Rescue and Relief. Minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;
    4. Business Interruptions. Minimize prolonged business interruptions;
    5. Damage to Public Facilities. Minimize damage to public facilities and utilities such as water and gas mains, electric, telephone and sewer lines, streets and bridges located in floodplains;
    6. Tax Base. Help maintain a stable tax base by providing for the sound use and development of flood-prone areas in such a manner as to minimize future flood blight areas; and
    7. Notification. Insure that potential buyers are notified that property is in a flood area.
  • Warning and Disclaimer or Liability. The degree of flood protection required by this Article is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. On rare occasions greater floods can and will occur and flood heights may be increased by manmade or natural causes. This Article does not imply that land outside the areas of special flood hazards or uses permitted within such areas will be free from flooding or flood damages. This Article shall not create liability on the part of the City or any of its officials or employees for any flood damages that result from reliance on or lawful administrative decisions made under this Article.

    • Effective on: 5/20/2019

    Sec. 14.401.4 Methods of Reducing Flood Losses

    In order to accomplish its purposes, this Article uses the following methods:

    1. Danger Uses. Restrict or prohibit uses that are dangerous to health, safety, or property in times of flood, or cause excessive increases in flood heights or velocities;
    2. Vulnerable Uses. Require that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;
    3. Alteration of Floodplains. Control the alteration of natural floodplains, stream channels, and natural protective barriers, which are involved in the accommodation of floodwaters;
    4. Development Activities. Control filling, grading, dredging and other development which may increase flood damage;
    5. Flood Barriers. Prevent or regulate the construction of flood barriers which will unnaturally divert floodwaters or which may increase flood hazards to other lands.

    Effective on: 5/20/2019

    Sec. 14.401.5 General Standards

  • Lands to which This Article Applies. This Article shall apply to all areas of special flood hazard within the jurisdiction of this UDC.
  • Basis for Establishing the Areas of Special Flood Hazard. The areas of special flood hazard identified by the Federal Emergency Management Agency in the current scientific and engineering report entitled, “The Flood Insurance Study (FIS) for Liberty County, Texas and Incorporated Areas” dated May 2, 2008 with accompanying flood insurance rate maps (FIRM and/or FBFM) dated May 2, 2008 and any revisions to such report or map are hereby adopted by reference and declared to be a part of this Article.
  • Compliance. No structure or land shall be located, altered, or have its use changed without full compliance with the terms of this Article and other applicable regulations.
     

      1. Effective on: 5/20/2019

      Sec. 14.402.1 Establishment of Floodplain Development Permit

      A Floodplain Development Permit shall be required in accordance with Sec. 14.603.7, Floodplain Development Permit, to ensure conformance with the provisions of this Article.

      Effective on: 5/20/2019

      Sec. 14.402.2 General Standards

      In all areas of special flood hazards the following provisions are required for all new construction and substantial improvements:

      1. Anchoring. All new construction or substantial improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy;
      2. Flood Damage Minimization. All new construction or substantial improvements shall be constructed by methods and practices that minimize flood damage;
      3. Materials. All new construction or substantial improvements shall be constructed with materials resistant to flood damage;
      4. Electrical, Mechanical, and Plumbing Systems. All new construction or substantial improvements shall be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
      5. Water Supply. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;
      6. Wastewater. New and replacement wastewater systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and discharge from the systems into floodwaters; and
      7. On-Site Systems. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

      Effective on: 5/20/2019

      Sec. 14.402.3 Specific Standards

      In all areas of special flood hazards where base flood elevation data has been provided as set forth in Sec. 14.401.5.B, Basis for Establishing the Areas of Special Flood Hazard, Sec. 14.501.8.B, Duties and Responsibilities of the Floodplain Administrator, or Sec. 14.402.4.C, Base Flood Elevation Data, the following provisions are required.

      1. Residential Construction. New construction and substantial improvement of any residential structure other than a manufactured home shall have the lowest floor (including basement), elevated to or above the base flood elevation. A licensed professional engineer, architect, or registered professional land surveyor shall submit a certification to the Floodplain Administrator verifying that the standard of this Subsection is satisfied.
      2. Mixed Use or Nonresidential Construction. New construction and substantial improvements of any mixed use or nonresidential structure shall either have the lowest floor (including basement) elevated to or above the base flood level or together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A licensed professional engineer or architect shall develop and/or review structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction are in accordance with accepted standards of practice as outlined in this Subsection. A record of such certification which includes the specific elevation (in relation to mean sea level) to which such structures are floo-proofed shall be maintained by the Floodplain Administrator.
      3. Enclosures. For new construction and substantial improvements, fully enclosed areas below the lowest floor may be used solely for parking of vehicles, building access, or storage. These areas shall be designed and constructed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a licensed professional engineer or architect or meet or exceed the following minimum criteria:
        1. Openings on Walls. A minimum of two openings on separate walls having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided;
        2. Bottom of Openings. The bottom of all openings shall be no higher than one foot above grade; and
        3. Coverings or Devices. Openings may be equipped with screens, louvers, valves, or other coverings or devices provided that they permit the automatic entry and exit of floodwaters.

        4. Access. Access to the enclosed area must be the minimum necessary to allow for parking of vehicles (garage door), storage (standard exterior door), or entry to the living area (stairway or elevator).

        5. No Habitable Space. The interior portion of the enclosed areas may not be partitioned, temperature-controlled, or finished into separate rooms.

      1. Manufactured Homes.
        1. Zone A. All manufactured homes placed within Zone A on a community’s Flood Hazard Boundary Map (FHBM) or Flood Insurance Rate Map (FIRM) shall be installed using methods and practices that minimize flood damage. For the purposes of this requirement, manufactured homes must be elevated and anchored to resist flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.
        2. Zones A1-30, AH, and AE. Manufactured homes that are placed or substantially improved within Zones A1-30, AH, and AE on the community’s FIRM shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement on sites:
          1. Outside of a manufactured home park or subdivision;
          2. In a new manufactured home park or subdivision;
          3. In an expansion to an existing manufactured home park or subdivision; or
          4. In an existing manufactured home park or subdivision on which a manufactured home has incurred substantial damage as a result of a flood..
        1. Other Manufactured Homes. Manufactured homes that are placed or substantially improved on sites in an existing manufactured home park or subdivision within zones A1-30, AH and AE on the community’s FIRM that are not subject to the provisions of subsection 2 of this Section be elevated so that either:
          1. The lowest floor of the manufactured home is at or above the base flood elevation; or
          2. The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.
      1. Recreational Vehicles.
        1. Standards. Recreational vehicles placed on sites within zones A1-30, AH, and AE on the community’s FIRM shall either:
          1. Be on the site for fewer than 180 consecutive days;
          2. Be fully licensed and ready for highway use; or
          3. Meet the permit requirements of Section 3.715(a), and the elevation and anchoring requirements for manufactured homes in subsection D., Manufactured Homes, of this Section.
        1. Highway Use. A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions.

      Effective on: 5/20/2019

      Sec. 14.402.4 Standards for Subdivision Proposals

    1. Applicable Provisions. All subdivision proposals which, for the purposes of this Section, include the placement of manufactured home parks shall be consistent with all applicable provisions of this Article.
    2. Permit. All subdivision proposals shall meet the Floodplain Development Permit requirements of Sec. 14.603.7, Floodplain Development Permit.
    3. Base Flood Elevation Data. The applicant shall generate base flood elevation data for subdivision proposals and other proposed development that is greater than 50 lots or five acres, whichever is lesser, if not otherwise provided pursuant to Sec. 14.401.5.B, Basis for Establishing the Areas of Special Flood Hazard, and Sec. 14.501.8.B, Duties and Responsibilities of the Floodplain Administrator.
    4. Adequate Drainage. All subdivision proposals shall have adequate drainage provided to reduce exposure to flood hazards.
    5. Public Facilities. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical, and water systems located and constructed to minimize or eliminate flood damage.

      6. Effective on: 5/20/2019

      Sec. 14.402.5 Standards for Areas of Shallow Flooding (AO/AH Zones)

      Located within the areas of special flood hazard established in Sec. 14.401.5.B, Basis for Establishing the Areas of Special Flood Hazard are areas designated as shallow flooding. These areas have special flood hazards associated with flood depths of 1 to 3 feet where a clearly defined channel does not exist, where the path of flooding is unpredictable, and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply:

      1. Residential Structures. All new construction and substantial improvements of residential structures shall have the lowest floor (including basement) elevated to or above the base flood elevation or the highest adjacent grade at least as high as the depth number specified in feet on the community’s FIRM (at least 2 feet if no depth number is specified).
      2. Mixed Use and Nonresidential. All new construction and substantial improvements of mixed use and nonresidential structures shall: 
        1. Elevation. Have the lowest floor (including basement) elevated to or above the base flood elevation or the highest adjacent grade at least as high as the depth number specified in feet on the community’s FIRM (at least 2 feet if no depth number is specified); or
        2. Watertight. Together with attendant utility and sanitary facilities, be designed so that below the base specified flood depth in an AO zone, or below the base flood elevation in an AH zone, the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads of effects of buoyancy.
      1. Certification. A licensed professional engineer or architect shall submit a certification to the Floodplain Administrator that the standards of this section are satisfied.
      2. Drainage Paths. Within zones AH or AO adequate drainage paths shall be provided around structures on slopes, to guide floodwaters around and away from proposed structures.

      Effective on: 5/20/2019

      Sec. 14.402.6 Floodways

      Located within areas of special flood hazard established in Sec. 14.401.5.B, Basis for Establishing the Areas of Special Flood Hazard , 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 shall apply:

      1. Encroachments Generally. Encroachments are prohibited, including fill, new construction, substantial improvements, and other development within the adopted regulatory floodway 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.
      2. Permitted Encroachments. If subsection A, Encroachments Generally, above is satisfied, all new construction and substantial improvements shall comply with all applicable provisions of this Section.
      3. Increase in BFE. Under the provisions of 44 CFR Chapter 1, Section 65.12, of the National Flood Insurance Program regulations, a community may permit encroachments within the adopted regulatory floodway that would result in an increase in base flood elevations, provided that the community first completes all of the provisions required by Section 65.12.
       

       

      Effective on: 5/20/2019