Unless specifically defined below, words or phrases used in this article shall be interpreted to give them the meaning they have in common usage and to give this article its most reasonable application:
Angle of flare.The angle between the direction of a wingwall and the centerline of a culvert or storm drainage outlet or inlet.
Appeal.A request for review or interpretation of any provision of this article or a request for a variance.
Applicant.Any firm, entity, partnership, company, public utility company or individuals, who plan to clear, grub, fill, excavate, grade or otherwise remove the vegetative cover of land, or who plan to either subdivide land and install the appropriate infrastructure or renovate existing structures, shall become applicants for a development permit upon submission of the appropriate application materials.
Apron.A floor or lining to protect a surface from erosion, for example, the pavement below chutes or spillways or at the toes of dams.
Area of shallow flooding.A designated AO or AH zone on the flood insurance rate map. The base flood depths range from one to three feet, a clearly defined channel does not exist, and the path of flooding is unpredictable and indeterminate.
Area of special flood hazard.The land in the floodplain within a community subject to a one-percent or greater chance of flooding in any given year.
Base flood.The flood having a one-percent chance of being equaled or exceeded in any given year, determined based upon the FEMA guidelines and as shown in the current effective flood insurance study. This 100-year mean recurrence interval storm event is based on existing watershed conditions (also see "design flood").
Best management practices (BMPs).Schedules of activities, prohibitions of practices, general good housekeeping practices, pollution prevention and educational practices, maintenance procedures, and other management practices to prevent or reduce the discharge of pollutants directly or indirectly to stormwater, receiving waters, or stormwater conveyance systems. BMPs also include treatment practices, operating procedures, and practices to control site runoff, spillage or leaks, sludge or water disposal, or drainage from raw materials storage.
Builder.A person, partnership or corporation engaged in clearing, grubbing, filling, excavating, grading, constructing a pad, installing service utility lines and/or constructing or placing a building(s) or other structure(s) on a lot or other type of tract of land that is owned by the person, partnership or corporation, and that will not be further subdivided into other lots.
City.The City of Lancaster, Texas, or any authorized person acting on its behalf.
Channel.A natural or artificial stream that conveys water. Channels are often further classified by their size and purpose. For example, there are primary and secondary channels based on size, but diversions, waterways and chutes are also channels.
Channel improvement.The improvement of the flow characteristics of a channel by clearing, excavating, realigning, lining or other means in order to increase its capacity. The term is sometimes used to mean channel stabilization.
Channel stabilization.Erosion prevention and stabilization of velocity distribution in a channel using jetties, drops, revetments, vegetation and other measures.
Check dam.A small dam constructed in a gulley or other small watercourse to decrease the streamflow velocity, minimize channel scour and promote deposition of sediment.
City-maintained land.Any land in actual ownership of the city; it does not include any type of easements that remain in private ownership.
Common plan of development or sale.A construction activity that is completed in separate stages, separate phases, or in combination with other construction activities. A common plan of development or sale is identified by the documentation for the construction project that identifies the scope of the project, and may include plats, blueprints, marketing plans, contracts, building permits, a public notice or hearing, zoning requests, or other similar documentation and activities.
Conduit.Any closed device for conveying flowing water.
Construction activity.Activities including clearing, grading, and excavation that are subject to TPDES general construction permits. It does not include routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, and original purpose of a ditch, channel, or other similar stormwater conveyance. Additionally, it does not include the routine grading of existing dirt roads, asphalt overlays of existing roads, the routine clearing of existing rights-of-way, and similar maintenance activities.
(1) Small construction activity.Construction activities including clearing, grading, and excavating that result in land disturbances of equal to or greater than one acres but less than five acres. Small construction activity also includes the disturbance of less than one acre of total land area that is part of a larger common plan of development or sale if the larger common plan will ultimately disturb equal to or greater than one acre of land.
(2) Large construction activity.Construction activities including clearing, grading, and excavating that result in land disturbances of equal to or greater than five acres. Large construction activity also includes the disturbance of less than five acres of total land area that is part of a larger common plan of development or sale if the larger common plan will ultimately disturb equal to or greater than five acres of land.
Cover, vegetative.All plants of all sizes and species found on an area, irrespective of whether they have forage or other value, but especially used to refer to vegetation producing a mat on or immediately above the soil surface. Temporary vegetative cover refers to the use of annual plants for the cover, while permanent vegetative cover refers to the use of perennial plants.
Crest.The top of a dam, dike, spillway or weir, frequently restricted to the overflow portion.
Critical feature.An integral and readily identifiable part of a flood-protection system, without which the flood protection provided by the entire system would be compromised.
Design basin.A dry basin or depression constructed for the purpose of temporarily storing stormwater runoff and discharging all of that water over time at a rate reduced from the rate that would have otherwise occurred.
Design flood.When in the context of floods, floodplains or flood hazards, the design flood is that flood having a one-percent chance of being equaled or exceeded in any given year, based upon fully developed watershed conditions (also see "base flood").
Developer.A person, partnership or corporation who owns a tract of land and who is engaged in clearing, grubbing, filling, mining, excavating, grading, installing streets and utilities to be dedicated to or accepted by the city and/or otherwise preparing that tract of land for the eventual division of the tract into one or more lots on which building(s) or other structure(s) will be constructed or placed.
Development.Any manmade change to improved or unimproved real estate, including, but not limited to, adding buildings or other structures, mining, dredging, filling, grading, paving, excavation, drilling operations, grading, clearing or removing the vegetative cover.
Discharge (hydraulics).(1) Rate of flow; specifically, fluid flow.
A volume of fluid passing a point per unit time, commonly expressed as cubic feet per second.
Disturbance.Any operation or activity, such as clearing, grubbing, filling, excavating, mining, cutting and grading, or removing channel linings, which results in the removal or destruction of the protective cover of soil, including vegetative cover, channel linings, retaining walls, and slope protection.
Disturbed areas.Any area or tract of land in which a disturbance is occurring or has occurred but that has not been stabilized.
Elevated building.In the case of FEMA-designated zones A1-30, AE, A, A99, AO, AH, B, C, X and D, "elevated building" includes a building elevated by means of fill, so that the lowest finished floor of the building is at least two feet above the water surface elevation of the design flood.
Emergency spillway.A spillway built to carry runoff in excess of that carried by the principal spillway.
Entrance head.The head required to cause flow into a conduit or other structure; it includes both entrance loss and velocity head.
Entrance loss.The head lost in eddies or friction at the inlet to a conduit, headwall or structure.
Equal conveyance.The principle of reducing stream conveyance for a proposed alteration with a corresponding reduction in conveyance to the opposite bank of the stream. The right of equal conveyance applies to all owners and uses and may be relinquished only by written agreement.
Erosion.The wearing away of land by action of wind and water.
Existing construction.For the purposes of determining rates, structures for which the "start of construction" commenced before the effective date (January 31, 1978) of Ordinance 1046. "Existing construction" may also be referred to as "existing structures."
Flood insurance rate map (FIRM).The official map on which the Federal Emergency Management Agency has delineated both the areas of special flood hazard and the risk premium zones applicable to the community.
Flood insurance study.The official report in which the Federal Emergency Management Agency has provided flood profiles, as well as the flood boundary/floodway map and the water surface elevation of the base flood.
Flood or flooding.A general and temporary condition of partial or complete inundation of normally dry land areas from:
(1) The overflow of inland waters; and/or
The unusual and rapid accumulation or runoff of surface waters from any source.
Flood protection system.Those physical structural works for which funds have been authorized, appropriated and expended and which have been constructed specifically to modify flooding in order to reduce the extent of the areas within a community subject to a "special flood hazard" and the extent of the depths of associated flooding. Such a system typically includes dams, reservoirs, levees or dikes. These specialized flood-modifying works are those constructed in conformance with sound engineering standards.
Floodway.The channel of the river or other watercourse and adjacent land areas that must be reserved in order to pass the base flood discharge without increasing flood depth.
Flume.Any open conduit on a prepared grade, trestle or bridge.
Freeboard.The distance between the design flood elevation and the top of an open channel, dam, levee or detention basin to allow for wave action, floating debris or any other condition or emergency without overflowing the structure.
Functionally dependent use.A use which cannot perform its intended purpose unless it is located or carried out in proximity to water. The term includes only docking facilities.
Gabion.A galvanized wire basket filled with stone for structural purposes. When fastened together, they may be used as retaining walls, revetments, slope protection and similar structures.
Grading.Any stripping, cutting, filling, stockpiling or combination thereof which modifies the existing land surface contour.
Grass.Any member of the botanical family Gramineae; herbaceous plants with bladelike leaves arranged in two ranks on a round to flattened stem. Common examples are fescue, Bermuda grass and Bahia grass. The term "grass" is sometimes used to indicate a combination of grass and legumes grown for forage or turf purposes.
Hazardous materials.Any substance identified or listed as a hazardous waste by the EPA pursuant to 40 CFR part 261, and also includes any material, including any substance, waste, or combination thereof, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may cause, or significantly contribute to, a substantial present or potential hazard to human health, safety, property, or the environment when improperly treated, stored, transported, disposed of, or otherwise managed.
Highest adjacent grade.The highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.
Hydraulic gradient.A line representing the pressure head available at any given point within the drainage system.
Hydrograph.A graph showing, for a given point on a stream or drainage system, the discharge, stage, velocity or other property of water with respect to time.
Illicit connection.Any manmade conveyance connecting an illicit discharge directly to a municipal separate storm sewer.
Illicit discharge.Any discharge to a municipal separate storm sewer that is not entirely composed of stormwater, except discharges authorized under an NPDES or TPDES permit and discharges resulting from emergency firefighting activities.
Inlet (hydraulics).(1) A surface connection to a closed drain;
A structure at the diversion end of a conduit;
The upstream end of any structure through which water may flow.
Levee.A manmade structure, usually an earthen embankment, designed and constructed in accordance with sound engineering practices to contain, control or divert the flow of water so as to provide protection from temporary flooding.
Levee system.A flood protection system which consists of a levee or levees and associated structures, such as closure and drainage devices, which are constructed and operated in accordance with sound engineering practices.
Letters of map change.(1) CLOMA.A conditional letter of map amendment (CLOMA) is FEMA's comment on whether a proposed project would be excluded from the special flood hazard area (SFHA) shown on the effective National Flood Insurance Program (NFIP) map. There is no appeal period. The letter becomes effective on the date sent. This letter does not revise an effective NFIP map, it indicates whether the project, if built as proposed, would or would not be removed from the SFHA by FEMA if later submitted as a request for a letter of map amendment.
(2) CLOMR.A conditional letter of map revision (CLOMR) is FEMA's comment on a proposed project that would affect the hydrologic and/or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway or effective base flood elevations. There is no appeal period. The letter becomes effective on the date sent. This letter does not revise an effective National Flood Insurance Program map, it indicates whether the project, if built as proposed, would or would not be removed from the special flood hazard area by FEMA if later submitted as a request for a letter of map revision.
(3) CLOMR-F.A conditional letter of map revision based on fill (CLOMR-F) is FEMA's comment on whether a proposed project involving the placement of fill would exclude an area from the special flood hazard area (SFHA) shown on the National Flood Insurance Program (NFIP) map. There is no appeal period. The letter becomes effective on the date sent. This letter does not revise an effective NFIP map, it indicates whether the project, if built as proposed, would or would not be removed from the SFHA by FEMA if later submitted as a request for a letter of map revision based on fill.
(4) LOMA.A letter of map amendment (LOMA) is an official amendment, by letter, to an effective National Flood Insurance Program map. A LOMA establishes a property's location in relation to the special flood hazard area. There is no appeal period. The letter becomes effective on the date sent.
(5) LOMR.A letter of map revision (LOMR) is an official revision, by letter, to an effective National Flood Insurance Program map. A LOMR may change flood insurance risk zones, floodplain and/or floodway boundary delineations, planimetric features, and/or base flood elevations. See the LOMR effective chart to determine when a LOMR becomes effective.
(6) LOMR-F.A letter of map revision based on fill (LOMR-F) is an official revision, by letter, to an effective National Flood Insurance Program map. A LOMR-F provides FEMA's determination concerning whether a structure or parcel has been elevated on fill above the base flood elevation and excluded from the special flood hazard area. The letter becomes effective on the date sent.
Lowest floor.The lowest floor of the lowest enclosed area (including basement). An unfinished or flood-resistant enclosure, usable solely for the parking of vehicles, building access or storage in an area other than a basement area is not considered a building's lowest floor, provided that such enclosure is not built so as to render the structure in violation of the applicable nonelevation design requirements of FEMA 60.3.
Major streams.The major streams in the city, as defined in this article, are Bear Branch, Deep Branch, Halls Branch, Floyd Branch, Keller Branch, Keller Tributary, Mills Branch, Newton, Branch, Runyon Springs, Ten Mile Creek, and any other stream within the city limits with a FEMA-defined floodplain.
Manning equation.The uniform flow equation used to relate velocity, hydraulic radius and energy gradient slope and roughness characteristics of the flow path.
Manufactured home.A structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities. For floodplain management purposes, the term "manufactured home" also includes park trailers, travel trailers and other similar vehicles placed on a site for greater than 180 consecutive days. For insurance purposes, the term "manufactured home" does not include park trailers, travel trailers and other similar vehicles.
Mean sea level.For the purposes of the National Flood Insurance Program, the National Geodetic Vertical Datum (NGVD) of 1929 or other datum to which base flood elevations shown on a community's flood insurance rate map are referenced.
Mulching.The application of plant or other suitable materials on the soil surface to conserve moisture, reduce erosion and aid in establishing plant cover.
Municipal separate storm sewer system or MS4.The system of conveyances (including roads with drainage systems, municipal streets, alleys, catch basins, curbs, gutters, ditches, manmade channels, or storm drains) owned and operated by the city and designed or used for collecting or conveying stormwater, and which is not used for collecting or conveying sewage.
National Pollutant Discharge Elimination System or NPDES.A national permitting program for the discharge of pollutants to waters of the United States, whether the permit is applicable on an individual, group, or general basis. In the state of Texas, the EPA retains authority for permitting oil and gas exploration activities and Indian Country land through the NPDES program.
Natural drainage.The dispersal of surface waters through ground absorption and by drainage channels formed by the existing surface topography which exists at the time of adoption of this article or formed by any manmade change in the surface topography.
Natural floodway.The effective area of a channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the "design flood" without cumulatively increasing the water surface elevation. This floodway differs from the "regulatory floodway."
New construction.Structures for which the "start of construction" commenced on or after the adoptive date of this article.
Outfall.A point source at the point where a municipal separate storm sewer discharges to water in the state and does not include open conveyances connecting two municipal separate storm sewers, or pipes, tunnels, or other conveyances that connect segments of the same stream or other waters of the U.S. and are used to convey waters of the U.S.
Peak discharge.The maximum instantaneous flow from a given storm condition at a specific location.
Permanent erosion controls.Stabilization of erosive or sediment-producing areas by the use of means or techniques that will provide protection against erosion losses for an indefinite time period.
Pollutant.Anything which causes or contributes to pollution. Pollutants may include, but are not limited to: paints, varnishes, and solvents; oil and other automotive fluids; non-hazardous liquid and solid wastes and yard wastes; refuse, rubbish, garbage, litter, or other discarded or abandoned objects, ordinances, and accumulations, so that same may cause or contribute to pollution; floatables; pesticides, herbicides, and fertilizers; hazardous substances and wastes; sewage, fecal coliform and pathogens; dissolved and particulate metals; animal wastes; wastes and residues that result from constructing a building or structure; and noxious or offensive matter of any kind.
Pollution.(From Texas Water Code, section 26.001(14)) The alteration of the physical, thermal, chemical, or biological quality of, or the contamination of, any water in the state that renders the water harmful, detrimental, or injurious to humans, animal life, vegetation, or property, or to the public health, safety, or welfare, or impairs the usefulness or the public enjoyment of the water for any lawful or reasonable purpose.
Principal spillway.Generally, is constructed of permanent material and designed to regulate the normal water level, provide flood protection and reduce the frequency of operation of the emergency spillway.
Probable maximum flood.The upper limit of a flood likely to occur as determined by the Corps of Engineers' criteria.
Public erosion nuisance.A situation in which erosion of or sediment from one location is causing a bothersome or unsightly condition on another property owned by a different individual or entity. A bothersome or unsightly condition or burden includes sediment, mud or similar debris originating from one property but being deposited onto a second off-site property in which that off-site owner may have to remove or clean up the deposit due to liability, statutory, aesthetic, drainage or property damage concerns. The adversely affected off-site property owner could be a private citizen, corporation, government or other entity.
Rainfall intensity.The rate at which rain is falling at any given instant, usually expressed in inches per hour.
Rational formula.The means of relating runoff with the area being drained, the characteristics of the land use and the intensity of the storm rainfall.
Redevelopment.Alterations of a property that changed the "footprint" of a site or building in such a way that there is a disturbance of equal to or greater than one (1) acre of land. This term does not include such activities as exterior remodeling.
Regulatory floodway.The channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the "base flood," as calculated by the Federal Emergency Management Agency, without cumulatively increasing the water surface elevation more than a designated height. This floodway is used by FEMA to determine compliance with its regulations.
Retention basins.A pond or other water body which has been designed to have both a conservation pool for holding some water indefinitely and a flood storage pool for storing stormwater runoff on a temporary basis for the purpose of reducing the peak discharge from the basin.
Riprap.Broken rock, cobbles, boulders, or concrete placed on earth surfaces, such as the face of a dam or the bank of a stream, for protection against the action of water.
Runoff.That portion of the precipitation that makes its way toward stream channels or lakes as surface or subsurface flow. When the term "runoff" is used alone, surface runoff usually is implied.
Sediment.Solid soil material, both mineral and organic, that is being moved or has been moved from its original site by wind, gravity, flowing water or ice. Also sometimes referred to as "silt" or "sand."
Sheet flow.Water, usually storm runoff, flowing in a thin layer over the ground surface. Synonymous with "overland flow."
Significant rise.Any rise in the design floodwater surface elevation at a particular stream location.
Soil.The unconsolidated mineral and organic material on the immediate surface of the earth that serves as a natural medium for the growth of plants.
Special flood hazard area.Areas inundated by the design flood and/or floodplain areas designated on the current flood insurance rate maps.
Stabilized.To be protected from possible erosion losses, usually by the use of vegetative cover.
Standard project flood.A flood that has a magnitude of approximately one-half of the probable maximum flood, as determined on a case-by-case basis using the Corps of Engineers' current criteria.
Start of construction.For a structure, "start of construction" includes substantial improvement and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, placement or other improvement was within 180 days of the permit date. The actual start means either the first placement of permanent construction of a structure on a site, such as the pouring of a slab or footings, the installation of piles, the construction of columns or any work beyond the stage of excavation or the placement of a manufactured home on a foundation. Permanent construction of a structure does not include land preparation, such as clearing, grading and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure.
Storm frequency.An expression or measure of how often a hydrologic event of given size or magnitude should, on an average, be equaled or exceeded.
Stormwater.Any flow occurring during or after any form of natural precipitation, including rainfall runoff, snowmelt runoff, and surface runoff and drainage.
Structural control (or practice).A pollution prevention practice that requires the construction of a device, or the use of a device, to capture or prevent pollution in stormwater runoff. Structural controls and practices may include but are not limited to: wet ponds, infiltration basins, stormwater wetlands, silt fences, earthen dikes, drainage swales, sediment traps, check dams, stabilized construction entrances, subsurface drains, storm drain inlet protection, rock outlet protection, reinforced soil retaining systems, gabions, and temporary or permanent sediment basins.
Structure.A walled and roofed building, a manufactured home, a substation or a gas or liquid storage tank that is principally above ground. When used in the context of stormwater, the term means a drainage improvement, such as dams, levees, bridges, culverts, headwalls, flumes, etc.
Substantial improvement.Any combination of repairs, reconstruction or improvements of a structure, the cumulative cost of which equals or exceeds 50 percent of the initial market value of the structure either:
(1) Before the first improvement or repair is started; or
If the structure has been damaged and is being restored, before the damage occurred.
For the purposes of this definition, substantial improvement is considered to occur when the first alteration of any wall, ceiling, floor or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure. Incremental improvements over a period of time, the cumulative cost of which equals or exceeds 50 percent of the market value at the time of the first improvement, shall be considered a substantial improvement. The term does not, however, include either of the following: |
(1) | Any project for the improvement of a structure to comply with existing state or local health, sanitary or safety code specifications which are solely necessary to assure safe living conditions; |
(2) | Any alteration of a structure listed on the National Register of Historic Places or a state inventory of historic places. |
Temporary erosion protection.The stabilization of erosive or sediment-producing areas for a specific time period, usually during a construction job.
Texas Commission on Environmental Quality or TCEQ.The state commission on environmental quality, any duly authorized official of said agency, or any successor agency. The permitting authority for stormwater discharges to the state including industrial, construction and MS4 permits.
Texas Pollutant Discharge Elimination System or TPDES.The state permitting program enforced by the state commission on environmental quality (TCEQ) that authorizes the discharge of pollutants to waters of the United States, whether the permit is applicable on an individual, group, or general area-wide basis.
Time of concentration.The estimated time in minutes or hours required for a drop of water to flow from the most remote point in the drainage area to the point at which the discharge is to be determined.
Use.Any purpose for which a building or other structure or a tract of land may be designed, arranged, intended, maintained or occupied; or any activity, occupation, business or operation carried on, or intended to be carried on, in a building or other structure or on a tract of land.
Use permit.The permit required before any use may be commenced.
Variance.A grant of relief to a person from the requirements of this article. A variance, therefore, permits construction or development in a manner otherwise prohibited by this article.
Violation.The failure of a structure or other development to be fully compliant with this article. A structure or other development without the elevation certificate, other certifications or other evidence, as required by the public works director, is presumed to be in violation until such time as that documentation is provided.
Water surface elevation.The height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929 (or other datum, where specified), of floods of various magnitudes and frequencies in the floodplains of riverine areas.
Watershed.The area drained by a stream or drainage system.
(Ordinance 2012-07-11 adopted 7/23/12)