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SEC. 51A-5.105.   FILLING IN THE FLOODPLAIN.
   (a)   Permit required.
      (1)   A person shall not deposit or store fill, place a structure, excavate, or engage in any other development activities in an FP area without first obtaining:
         (A)   a fill permit or a floodplain alteration permit from the director of water utilities; and
         (B)   all other permits required by county, state, and federal agencies.
      (2)   A fill permit allows the property to be developed at a specified elevation in compliance with this section.
      (3)   The director of water utilities shall maintain a record of all fill permits and floodplain alteration permits.
   (b)   Floodplain alteration permit process.
      (1)   The director of water utilities may issue a floodplain alteration permit if he or she determines that:
         (A)   the alteration does not remove an FP designation; and
         (B)   the alteration complies with all applicable engineering requirements in Subsection (g).
      (2)   The floodplain alteration permit may require hydrologic or hydraulic modeling as determined by the director of water utilities. Examples of situations that may require hydrologic or hydraulic modeling include, but are not limited to:
         (A)   A pool, tennis court, patio, cook area, deck, or other outdoor amenity above existing grade, but not above the base flood elevation.
         (B)   A fence that will block the flow of flood water during the 100-year flood event.
         (C)   A retaining wall projecting into the channel as compared to the existing grade.
         (D)   Elevated utilities that block the flow of flood water during the 100-year flood event.
         (E)   Additions to existing structures.
   (c)   Initiation of the fill permit process. An applicant for a fill permit shall submit an application to the director of water utilities on a form approved by the director and signed by all owners of the property.
   (d)   Preapplication conference.
      (1)   An applicant for a fill permit or a floodplain alteration permit that will require hydrologic or hydraulic modeling shall request a preapplication conference with representatives from the department of water utilities.
      (2)   At the preapplication conference, the director of water utilities shall determine what information is necessary for a complete evaluation of the proposed fill project. The applicant may be required to submit all necessary information, including, but not limited to the following:
         (A)   A vicinity map.
         (B)   The acreage figures for the entire tract, the area located in the floodplain, and the area proposed to be filled.
         (C)   A description of existing and proposed hydrologic and hydraulic analysis conducted.
         (D)   Plans that comply with the Landscape and Urban Forest Conservation Regulations in Article X of the Dallas Development Code, as amended.
         (E)   A table of values for analysis of the engineering criteria listed in Subsections (h)(1), (h)(2), and (h)(5).
         (F)   A water surface profile.
         (G)   A plan view showing existing and proposed contours and grading.
         (H)   Plotted cross-sections.
         (I)   An overall map of the project area.
         (J)   Drainage area map.
   (e)   Filling to remove an FP designation.
      (1)   In general. This subsection applies to applications to remove an FP designation from any regulatory floodplain.
      (2)   Review of application by departments.
         (A)   If the application is to remove an FP designation, the director of water utilities shall forward copies of the application to the director of development services, the chief planning officer, and the director of park and recreation for review.
         (B)   The director of development services, the chief planning officer, and the director of park and recreation shall review the application and advise the director of water utilities of the environmental impacts of the project, zoning concerns, or other concerns. If concerns are raised by one of these departments, the concerns must be addressed by the property owner prior to issuance of the fill permit. These departments shall also determine whether the applicant's property should be considered for public acquisition due to its ecological, scenic, historic, or recreational value.
      (3)   Neighborhood meeting. The water utilities department shall schedule and conduct a virtual or in-person neighborhood meeting on each application. The applicant or the applicant's representative must attend the neighborhood meeting. The director shall send written notice of the meeting to the applicant, to all owners of real property within 500 feet from the boundary of the subject property, and to persons and organizations on the early notification list on file with the department of development services. Measurements include the streets and alleys. The notice must be given not less than 10 days before the date set for the neighborhood meeting by depositing the notice properly addressed and postage paid in the United States mail to the property owners as evidenced by the last approved city tax roll. This notice must be written in English and Spanish if the area of request is located wholly or partly within a census tract in which 50 percent or more of the inhabitants are persons of Spanish origin or descent according to the most recent federal decennial census.
      (4)   Notice of public hearing and city council approval. If the city council is required to approve a fill permit in accordance with this paragraph, after the neighborhood meeting, the director of water utilities shall schedule a public hearing on the application. The city secretary shall give notice of the public hearing in the official newspaper of the city at least 15 days before the date of the public hearing. The director shall also send written notice of the public hearing to the applicant, to all owners of real property within 500 feet from the boundary of the subject property, and to persons and organizations on the early notification list on file with the department of development services. Except as provided in this paragraph, the city council may only deny an application if the application does not meet the requirements of Sections 51A-5.105(f) or (g) or required state or federal permits have been denied.
         (A)   Variance requested. If a variance to one of the engineering criteria outlined in Subsection (g) is requested, the fill permit will require city council approval. The city council may grant a variance to the requirements of Subsection (g) if the variance will not violate any provision of federal or state law or endanger life or property.
         (B)   Property acquisition. If the department of development services or park and recreation recommend public acquisition of property due to its ecological, scenic, historic, or recreational value, they must make a written recommendation to city council, and the director of water utilities shall provide a report to the city council on the application regarding environmental impacts and public acquisition issues. Once the recommendation is made, the city council may vote to approve a resolution authorizing the acquisition of the property under the laws of eminent domain and deny the fill permit to preserve the status quo until the property is acquired.
      (5)   Director approval.
         (A)   After the applicant has satisfied all requirements of Subsections (f) and (g), and it is determined that city council approval is not necessary under Paragraph (4), the director of water utilities shall approve or deny the application for a fill permit. The director may only deny an application if:
            (i)   the application does not meet the requirements of Sections 51A-5.105(f) or (g); or
            (ii)   required state or federal permits have been denied.
         (B)   The director of water utilities may postpone the approval of a fill permit if:
            (i)   required state and federal permits have not been addressed or obtained; or
            (ii)   concerns from the department of development services or the park and recreation department have not been addressed.
      (6)   Zoning map revision. A letter of map revision must be obtained from FEMA, if applicable, before an FP prefix may be removed from the official zoning district map. A building permit may be issued for construction of underground utilities; however, no building permit for construction of a structure may be issued until a final letter of map revision (LOMR) is obtained. Upon approval and receipt of a letter of map revision, the director of water utilities shall notify the director of development services, who shall remove the FP designation for the subject area from the official zoning district map.
   (f)   Filling operations. If a fill permit or floodplain alteration permit is approved, the filling operations must comply with the following requirements:
      (1)   Any excavation required by the specifications of the approved application must be conducted before or at the same time as placing fill. Excavated areas are required to maintain a minimum depth of one foot at the deepest point.
      (2)   For fill permits, the entirety of the building pad site must be filled to an elevation of at least two feet above the design flood elevation. Habitable structures elevated on piers in floodplain areas are prohibited.
      (3)   For fill permits, tthe lowest floor of any structure must be constructed at least three feet above the design flood elevation.
      (4)   For fill permits within interior drainage (sump) areas, the building pad site must be filled to a minimum elevation of one foot above the design flood elevation. Habitable structures elevated on piers in floodplain areas are prohibited.
      (5)   Fill material must consist of natural material including but not limited to soil, rock, gravel, or broken concrete. Decomposable matter, including but not limited to lumber, sheetrock, trees, tires, refuse, or hazardous, toxic material, is prohibited as fill material. Fill must be compacted to 95 percent standard proctor density.
      (6)   Before construction, erosion and sediment control devices such as straw hay bales, silt fences, or similar items must be installed to eliminate any transportation of sediment downstream. The property owner is responsible for removal of any sediment deposited by runoff as a result of filling.
      (7)   If compliance with a Texas Pollutant Discharge Elimination System (TPDES) permit is required for construction activities, a copy of the Notice of Intent (NOI) or the individual TPDES permit must be submitted to the director of water utilities and the director of the office of environmental quality and sustainability before beginning fill operations. The Stormwater Pollution Prevention Plan required by TPDES must be implemented no later than two days prior to commencement of construction activities.
      (8)   Fill shall be placed no more than five feet above the design flood elevation, except where necessary to match the existing elevation of the adjacent property as determined by the director of water utilities. In determining when it is necessary to match the existing elevation, the director shall consider the effects on local drainage and storm water management, the access needs of the property, and other public health and safety concerns.
      (9)   A copy of the approved fill permit must be posted and maintained at the fill site for inspection purposes until fill operations have been completed.
      (10)   After filling operations have been completed, the applicant shall submit a certification to the director of water utilities that proper fill elevations in the form of signed and sealed as-built topographic survey, compaction requirements, and all other specifications of the approved application have been followed. In addition, a letter of map revision (LOMR) submittal to FEMA and approval by FEMA is required.
      (11)   Encroachment into the floodway is prohibited unless FEMA issues a conditional letter of map revision (CLOMR).
   (g)   Engineering requirements for filling.
      (1)   Except for detention basins and ponds, alterations of the FP area may not increase the water surface elevation of the design flood of the creek upstream, downstream, or through the project area. Detention basins and ponds may increase the water surface elevation of the design flood provided the increase is within the detention basin's or pond's boundaries as approved by the director of water utilities.
      (2)   Alterations of the FP area may not create or increase an erosive water velocity on or off-site. The mean velocity of stream flow at the downstream end of the site after fill may not exceed the mean velocity of the stream flow under existing conditions.
      (3)   The effects of the existing and proposed public and private improvements will be used in determining water surface elevations and velocities. Any alteration of the FP area necessary to obtain a removal of an FP prefix may not cause any additional expense in any current or projected public improvements.
      (4)   The FP area may be altered only to the extent permitted by equal conveyance reduction on both sides of the natural channel.
      (5)   FP areas governed by a city council-adopted management plan that contains valley storage regulations must comply with the valley storage regulations contained in the plan. For all other FP areas, a valley storage maintenance agreement on a form provided by the city and approved as to form by the city attorney's office is required, and the following requirements apply:
         (A)   no loss of valley storage is permitted along a stream in which the upstream drainage area is three square miles or more;
         (B)   valley storage losses along streams in which the upstream drainage area is between 100 acres and three square miles may not exceed 15 percent, as calculated on a site by site basis; and
         (C)   valley storage losses along streams in which the upstream drainage area is less than 100 acres are not limited.
      (6)   An environmental impact study and a complete stream rehabilitation program must be approved before relocation or alteration of the natural channel or alteration of an environmentally significant area, or area deemed to house threatened or endangered species. The net environmental impacts of the proposal may not be negative. The environmental impact study must contain the following items:
         (A)   A description of the existing conditions of the site, adjacent properties, upstream and downstream creek sections for approximately 1,000 feet (unless conditions require additional information in the opinion of the director of water utilities), and creek and overbank areas. The description of these conditions must include:
            (i)   the characterization of creek features such as bed quality and material, pool-riffle sequences, natural ground water, springs, seeps, magnitude and continuity of flow, water quality, bank quality and material, vegetative cover and patterns, bank erosion, topographic relief, disturbances to the natural character of the creek, animal and aquatic life, and the extent and character of wetland areas; and
            (ii)   soil types and land uses of the site and surrounding area.
         (B)   A description of the proposed project. This description must include:
            (i)   the intended ultimate use of the site, or if that is not known, a description of the interim site plan, including construction access;
            (ii)   reasons why the creek or floodplain alteration is necessary; and
            (iii)   a site plan showing the floodplain and construction access necessary to perform the work.
         (C)   A description of at least three possible ways of handling the creek and floodplain, including:
            (i)   an alternative that assumes the creek and floodplain are not changed;
            (ii)   the applicant's proposed action; and
            (iii)    alternatives proposed by the director of water utilities.
         (D)   An identification of the impacts created by each alternative, describing in detail all of the positive and negative impacts upon the existing conditions described in Subparagraph (A), that would be created by each alternative.
         (E)   A recommended course of action based upon evaluation of the alternatives.
         (F)   Proposed strategies to mitigate adverse impacts. Examples of strategies include tree wells, temporary construction and permanent erosion and sedimentation controls, vegetative buffers, and replacement planting.
      (7)   The toe of any fill slope must parallel the natural channel to prevent an unbalanced stream flow in the altered FP area.
      (8)   To insure maximum accessibility to the FP area for maintenance and other purposes and to lessen the probability of slope erosion during periods of high water, maximum slopes of the filled area may not exceed four to one for 50 percent of the length of the fill and six to one for the remaining length of the fill. The slope of any excavated area may not exceed four to one unless the excavation is in rock. Vertical walls, terracing, and other slope treatments may be used provided no unbalancing of stream flow results and the slope treatment is approved as a part of a landscaping plan for the property.
      (9)   The elevation of excavated areas in the FP area may not be lower than one-third of the depth of the natural channel, as measured from the adjacent bank, except for excavation of lakes. Excavation must be at least 50 feet from the bank of the natural channel, except as necessary to provide proper drainage.
      (10)   A landscape and erosion control plan must be submitted and approved. Landscaping must incorporate natural materials (such as earth and stone) on cut and filled slopes when possible. The definitions of Section 51A-10.101 apply to this subsection. Except as otherwise provided, the installation, removal, and maintenance requirements contained in the urban forest conservation regulations, Division 51A-10.130 of the Dallas Development Code, apply. Each soil resource and erosion control plan must comply with the following criteria:
         (A)   The size, type, and location of all proposed replacement trees to mitigate the loss of existing trees must be shown. The tree types must be selected in accordance with the provisions of Section 51A-10.134 and must be approved by the city arborist as suitable for use under local climate and soil conditions.
         (B)   The specific plant materials proposed to protect fill and excavated slopes must be indicated. Plant materials must be suitable for use under local climate and soil conditions. In general, hydroseeding or sodding native grasses is acceptable during the summer months (May 1st to August 30th). Winter rye or fescue grass may be planted during times other than the summer months as a temporary measure until such time as the permanent planting can be accomplished.
         (C)   The proposed methods of erosion and sedimentation control, such as hay bales and sedimentation basins, to be used during construction must be shown in detail.
         (D)   The fill case applicant, current owners, and subsequent owners must maintain and assure the survival of all planted material until the property is developed and a permanent maintenance plan of record is established. Maintenance responsibility must be reflected in the submitted plans or supporting documents.
   (h)   Term of permit validity and extension procedures.
         (A)   A fill permit or floodway alteration permit is valid for a five-year time period from the date of issuance. The fill permit or floodway alteration permit automatically terminates if the filling operations have not been completed within the five-year time period.
         (B)   New permit required upon expiration. When a fill permit terminates, the applicant must apply for a new permit before filling the property. The new application must comply with the floodplain regulations that are in effect at the time that the request is considered by the director.
         (C)   New permit required with site plan change. If the applicant wishes to make changes to a site plan that will change the hydraulic model or acreage of fill placed on the fill permit application after a fill permit has been approved, a new permit must be obtained.
         (D)   Presumption of completion. Filling operations are deemed completed when the applicant:
            (i)   submits a certification in the form of a signed and sealed topographic survey to the director of water utilities that proper fill elevations have been achieved and the specifications of the approved application have been followed;
            (ii)   submits compaction test results indicating the site was compacted to 95 percent standard proctor density; and
            (iii)   obtains a letter of map revision (LOMR) from FEMA, if applicable. (Ord. Nos. 19455; 19786; 21299; 22920; 24085; 25047; 27697; 27893; 28424; 29478; 30994; 31314; 32002; 32039)