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HomeMy WebLinkAboutOrdinances (O-73-141 A)-11/20/1973 ( \ , (; ex 4'6 V/J ~ 'iD rJY 1/1/; d ~\'y'../I r,: Cok \ ),rc / : VOLUME -;J[;AGE~ ORDINANCE NO. 0-73-141 A I AN ORDINANCE ESTABLISHING FLOOD HAZARD AREAS AND PROVIDING FOR A FLOODWAY ZONING DISTRICT AND A FLOOD PLAIN ZONING DISTRICT; ESTABLISHING SPECIAL PROVISIONS APPLYING TO THE FLOOD HAZARD AREA; AND FURTHER PROVIDING FOR SPECIAL EXCEP- TION PERMITS. BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF COLLEYVILLE, TEXAS: SECTION 1.0 STATUTORY AUTHORIZATION, FINDINGS OF FACT AND PURPOSES 1.1 Statutory Authorization. The Legislature of the State r I 1.2 of Texas has in Article 8280-13 of the 61st Legislature session delegated the responsibility to local govern- mental units to adopt regulations designed to minimize flood losses. Therefore the City Council of Colleyville, Texas, do ordain as follows: Fi.ndings of Fact 1.21 Flood Losses Resulting from periodic Inundation - The flood hazard areas of Colleyville, Texas are subject to periodic inundation which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expendi- tures for flood protection and relief, and impairment of the tax base all of which adversely affect the public health, safety and general welfare. 1.22 General Causes of These Flood Losses - These flood losses are caused by: (I) The cumulative effect of obstructions in floodways causing increases in flood heights and velocities. (2) The occupancy of flood VOLtJ!.fE, .-rri, "T),' (TT,1, ' ti J ~- _1.'" \\J "'I ----1JR.-. hazard areas by uses vulnerable to floods of hazardous ,,-.. , to others which are inadequately elevated or otherwise protected from flood damages. 1.23 Methods Used to Analyze Flood Hazards - This Ordinance uses a reasonable method of analyzing flood hazards which consists of a series of interrelated stops: (1) Selection of a regulatory flood which is based upon engineering calculations which permit a considera- tion of such flood factors as its expected frequency of occurence, the area inundated, and the depth of inundation. The regulatory flood selected for this ordinance is representative of large floods known to have occurred in this region and which are reasonably characteristic of what can be expected to occur on the particular streams subject to this Ordinance. It is in the general order of a flood which could be expected to occur on the average of once every 100 years. (2) Calculation of water surface profiles based upon a hydraulic engineering analysis of the capacity of the stream channel and overbank areas to convey the regulatory flood. (3) Computation of the floodway required to convey this flood without increasing flood heights to an extent ~ which would cause substantial upstream or downstream, damage to existing or reasonably anticipated future- VOLUME.-rrI 0 ~PAGE I 7 ~ development. ~ (4) Delineation of floodway encroachment lines within which no obstruction is permitted which would cause such damage. (5) Delineation of the Flood Plain, i.e., that area outside the floodway encroachment lines but which is still subject to inundation by the regulatory flood. 1.3 Statement of Purpose It is the purpose of this Ordinance to promote the public health, safety and general welfare and to minimize those losses described in Section 1.21 by provisions designed to: 1.31 Restrict or prohibit uses which are dangerous to health, safety or property in times of flood or cause increase flood heights or velocities. 1.32 Require that uses vulnerable to floods, including public facilities which serve such uses, be pro- vided with flood protection at the time of initial construction. 1.33 Protect individuals from buying lands which are un- suited for intended purposes because of flood hazard. 1.34 Provide for the establishment of a comprehensive drainage plan for the major water courses of the city. 1.35 Insure the perpetuity and conservation of waterways, 11' ,1' ,'-''-'" ~..,.." ~T' (Jet \ \...-.,J..J"-'l..L-f __~l'.;.':....:...r.r_.,~ water courses, and greenways throughout the city as a natural protection against the hazards and losses connected with flooding. SECTION 2.0 GENERAL PROVISIONS 2.1 Lands to Which Ordinance Applies This Ordinance shall apply to all lands within the jurisdiction of the City of Colleyville shown on the Official Zoning Map as being located within the boundaries of the Floodway and Flood Plain districts. 2.2 Reference: Official Zoning Map The following Flood Plain information reports entitled: Flood Plain Information - Bear Creek, Dallas and Tarrant Counties, Texas, dated June, 1971, which were prepared by the Corps of Engineers, u.S. Army, Fort Worth, Texas District, are hereby attached to and made a part of the Official Zoning Map and this Ordinance. 2.3 Rules for Interpretation of District Boundaries The boundaries of the Floodway and Flood Plain districts shall be determined by scaling distances on the Official Zoning Map~ Where interpretation is needed as to the exact location of the boundaries of the districts as shown on the Official Zoning Map, as for example where there appears to be a conflict between a mapped boundary and actual field conditions, the Board of Adjustment shall make the necessary interpretation. The regulatory flood protection elevation for this point in question shall be r ;~,T"'--:>:__~~,,~. 9'1 ~ /". the governing factor in locating the district boundary on the land. The person contesting the location of the district boundary shall be given a reasonable opportunity to present his case to the Board and to submit his own technical evidence, is he so desires. 2.4 Compliance No structure, land or water, shall hereafter be used and no structure shall belocated, extended, converted or structurally altered without full compliance with the terms of this Ordinance and other applicable regulations. 2.5 Abrogation and Greater Restrictions It is not intended by this Ordinance to repeal, abrogate or impair any existing easements, covenants, or deed restrictions. However, where this Ordinance imposes greater restrictions, the provisions of this Ordinance shall prevail. All other ordinances inconsistent with this ordinance are hereby repealed to the extent of the inconsistency only. 2.6 Interpretation In their interpretation and application, the provisions of this Ordinance shall be held to be minimum requirements and shall be liberally construed in favor of the governing body and shall not be deemed a limitation or repeal of any other powers granted by State Statutes. 2.7 Warning and Disclaimer of Liability The degree of flood protection required by this Ordinance' .,,-, 71f. ..';....' --- -- .,j~O_ is considered reasonable for regulatory purposes and is ~ based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural cases, such as ice jams and bridge openings restricted by debris. This Ordinance does not imply that areas outside floodway and flood plain district boundaries or land uses permitted within such districts will be free from flooding or flood damages. This Ordinance shall not create liability on the part of the City of Colleyville or any officer or employee thereof for any flood damages that may result from reliance on this Ordinance or any administrative decision lawfully made thereunder. SECTION 3.0 ESTABLISHMENT OF ZONING DISTRICTS The flood hazard areas within the jurisdiction of this Ordinance are hereby divided into the two following districts: a Flood- way District (FW) and a Flood Plain District (FP). The boundaries of these districts shall be shown on the Official Zoning Map. Within these districts all uses not allowed as Permitted Uses or permissible as Special Exceptions shall be prohibited. SECTION 4.0 FLOODWAY DISTRICT (FW) 4.1 Permitted Uses -, The following open space uses shall be permitted within the Floodway District to the extent that they are not prohibited by any other ordinance and provided they do VOLUME _ Jlk PAGE IOL not require structures, fill or storage of materials or equipment: 4.11 Agricultural uses such as: general farming, pasture, grazing, outdoor plant nurseries, horticulture, vi ticul tun!!', 1::ruck. farmi.ng, forestry, sod farming, and wild crop harvesting. 4.12 Industrial-Commercial uses such as: loading areas, parking areas, airport landing strips. 4.13 Private and public recreational uses such as: golf courses, tennis courts, driving ranges, archery ranges, picnic grounds, swimming areas, parks, wild- life and nature preserves, game farms, fish hatcheries, shooting preserves, target ranges, trap and skeet ranges, hunting and fishing areas, hiking and horse- back riding trails. 4.14 Residential uses such as: lawns, gardens, parking areas and play areas. 4.2 Special Exceptions The following uses which involve structures (temporary or permanent), fill or storage of materials or equipment are permitted only upon application to the Zoning Administra~or and the issuance of a Special Exceition Permit by the Board of Adjustment as provided in Section 7.0, Special Exception Permits, of this Ordinance and subject to the provisions of Section 6.0 which applies to all floodway special exception uses and specifically to fill, structures, VOLUME ~~'PAG1!J /~~ and storage of materials or equipment. 4.21 ~,Y{';-::>'," ~:i,'ii"',*_'S"~-""" ",.,,~.,;,'''-''>''- Acce~~bry uses or structures. 4.22 Circuses, carnivals and similar transient amusement enterpr~ises . 4.23 Drive-in theaters, new and used car lots, road side stands, signs and bill boards. 4.24 Railroads, streets, bridges, utility transmission lines and pipe lines. 4.25 Storage yards for equipment, machinery or materials. 4.26 Kennels and stables 4.27 Other uses similar in nature to uses described in Section 4.1 or 4.2 which are consistent with the provisions set out in Section 1.3 and 6.0 of this Ordinance. SECTION 5.0 FLOOD PLAIN DISTRICT CFP) 5.1 Permitted Uses The following uses shall be permitted within the Flood Plain District to the extent that they are not prohibited by any other ordinance: 5.11 Any open-space use permitted in Section 4.1. 5.12 Any other non-structural use provided it is elevated above the regulatory flood protection elevation and a determination is made by the municipal engineer or other designated municipal employee that the use will not unduly restrict the capacity of the channels or floodway of tributaries to the main stream, drainage VOLUM?; >~ ./7\~ _1.tt::.. ":'AGF; ~ ditches, or any other drainage facilities or systems. 5.13 Structures constructed on fill provided the first floor or basement floor is above the regulatory flood protection elevation. The fill shall be at a point no lower than one (1) foot below the regulatory flood protection elevation for the parti- cular area and shall be extended at such elevation at least fifteen (15) feet beyond the limits of any structure or building erected thereon. 5.2 "-Special, Exceptions The following uses and structures are permitted only upon issuance of a Special Exception permit by the Board of Adjustment as provided in Section 7.0, Special Exception Permits, of this Ordinance and subject to the followigg provisions: 5.21 Structures if adequately floodproofed or otherwise protected as provided in Section 7.4 (a) - (e) to a point above the regulatory flood protection elevation. 5.22 Uses listed in Section 4.2 of this Ordinance and other similar uses which will not be subject to substantial flood damage and which will not cause flood losses on other lands or to the public. These may include uses which can be readily removed from flood hazard areas during times of flood. The Board may in the Special Exception Permit allow such uses VOLUME ~PAGE j()'/ to be located at an elevation below the regulatory flood protection elevation. SECTION 6.0 SPECIAL PROVISIONS APPLYING TO THE FLOOD HAZARD AREA 6.1 All Uses 6.11 Maintenance easements and access, watercourse, and parkway easements will be required within floodways and flood plain areas to assure maintainability and access to the floodway. Dedications will be encouraged for lands within the flood hazard area for future open space developments in accordance with the City's Master Plan The easements and/or dedicated lands shall meet the following requirements: (al All land within the waterway which lies between the banks of the creek shall be dedicated to the public use. (b) Easements or dedication of additional land along the waterways within the flood plain shall be included in any final plat or plat revision and shall meet the following requirements: (1) A maintenance easement with a minimum width of fifty (50) feet shall be re- quired on each side of the dedicated creek; (2) An access, watercourse, and parkway ease- ment with a total width of two hundred VOL U1.JE -:JJ1:p AGE' 165 -, (200) feet, exclusive of the area dedicated in (a) above, shall also be required. This easement may be coin- cidental with the maintenance easement and may be located entirely on one side of the dedicated creek or divided between the two sides; (3) Area within the flood plain when dedicated or shown as easements shall confirm to the city's plan for development and shall be approved by the Director of Public Works and Director of Parks. Land which is in an easement or is dedicated in accordance with these re- quirements may be counted as open space for computing density requirements and/or for open space requirements of the City's Zoning Ordinance. 6.12 No structure (temporary or permanent), fill, includ- ing fill for roads and levees, deposit, obstruction, storage of materials or equipment, or other uses shall be permitted which, acting alone or in combina- tion with existing or future uses unduly affects the efficiency or the capacity of the floodway or unduly increases flood heights. Consideration of the effects of a proposed use shall be based on a reasonable ~ ~ -~ ------~~-------~-~-- ---'-- 1'-'1"'~', JIE \ "'.:..,, , ',', -, '.." J /\ I "'-"~"-;-"------. ___~_..-./,...'_.r"'.~ assumption that there will be an equal degree of /'~ encroachment extending for a significant reach on both sides of the stream. 6.2 FILL 6.21 Any fill proposed to be deposited in the floodway must be shown to have some beneficial purpose and the amount thereof not greater than is necessary to achieve that purpose, as demonstrated by a plan submitted by the owner showing the uses to which the filled land will be put and the final dimensions of the proposed fill or other materials. 6.22 Such fill or other materials shall be protected against erosion by rip-rap, vegetative cover or bulkheading. 6.3 '-...Structur~s (temporary or permanent) 6.31 Structures shall not be designed for human habita- tion. 6.32 Structures shall have a low flood dama-e potential. 6.33 The structure or structures, if permitted, shall be constructed and placed on the building site so as to offer the minimum obstruction to the flow of flood waters. (1) Whenever possible, structures shall be con- structed with the longitudinal axis parallel to --....\ the direction of flood flow, and (2) So far as practicable, structures shall be VOL UME ---r;r- ~PAGE-LQZ. placed approximately on the same flood flow lines as those of adjoining structures. 6.34 Structures shall be firmly anchored to prevent floatation which may result in damage in other structures, restriction of bridge openings and other narrow sections of the stream or river~ and 6.35 Service facilities such as electrical and heating equipment shall be constructed at or above the regulatory flood protection elevation for the particular area. 6.4 Storage of Materials and Equipment 6.41 The storage or processing of materials that are buoyant, flammable, explosive or could be injurious to human, animal or plant life in time of flooding is prohibited. 6.42 Storage of other material or equipment may be allowed if not subject to major damage by floods, firmly anchored to prevent floatation, or shall be readily removable from the area within the limited time available after flood warning. SECTION 7.0 SPECIAL EXCEPTION PERMITS 7.1 Application for any use listed in this Ordinance as re- quiring a Special Exception Permit may be allowed only upon application to the Zoning Administrator on forms furnished by him and issuance of a Special Exception Permit by the Board. Upon receipt of the application, ~ VOL U1;JE --:=. ~p AG-FJ--JiJl the Administrator shall forthwith submit it to the Board. 7.2 Procedure to be Followed by Board in Passing on Special E~ception Permits Upon receiving an application for a Special Exception Permit involving the use of fill, construction of structures, or storage of materials, the Board may, prior to rendering a decision thereon: (a) Require the applicant to submit, where applicable, plans in triplicate drawn to scale showing the nature, location, dimensions and elevation of the lot, exist- ing or proposed structures, fill, storage of materials, flood proofing measures and the relationship of the above to the location of the channel and floodway and the regulatory flood elevation. (bI Transmit where necessary one copy of the information described in subsection (a) to the municipal engineer or other designated person or agency from which the Board of Adjustment may request expert technical assistance in evaluating the proposed project in relation to flood heights and velocities, the seriousness of flood damage to the use, the adequacy of the plans for protection and other technical matters. (cl Require, where special circumstances necessitate more detailed information, the applicant to furnish VOLUME ,~PAGE /~t[ ~ such of the following additional information as is deemed necessary by the Board for the evaulation of the effects of the proposed use upon flood flows and other factors necessary to render a decision on the suitability of the proposed use: (1) A typical valley cross-section showing the channel of the stream, elevation of land areas adjoining each side of the channel, cross- sectional areas to be occupied by the proposed development, and high water information. (2) Plan (surface view) showing elevations or contours of the ground~ pertinent structure, fill, or storage elevations~ size, location and spatial arrangement of all proposed and existing structures on the site~ location and elevations of streets, water supply, sanitary facilities, photographs showing existing land uses and vegetation upstream and downstream, soil types and other pertinent information. (3) Profile showing the slope of the bottom of the channel or flow line of the stream. (4) Specifications for building construction and materials, flood proofing, filling, dredging, grading, channel improvement, storage of materials, water supply, and sanitary facilities. VOLm,:E~ . PAGE~ 7.3 Factors Upon Which the Decision of the Board Shall Be /"'" Based; In passing upon such applications, the Board shall consider; (a) The danger to life and property due to increased flood heights or velocities caused by encroachments. (bl The danger that materials may be swept on to other lands or downstream to the injury of others. Ccl The proposed water supply and sanitation systems and the ability of these systems to prevent disease, contamination and unsanitary conditions. Cd) The susceptability of the proposed facility and /.... ( its contents to flood damage and the effect of such damage on the individual owner. (el The importance of the services provided by the proposed facility to the community. Cfl The requirements of the facility for a waterfront location. Cg) The availability of alternative locations not sub- ject to flooding for the proposed use. (hI The compatibility of the proposed use with existing development and development anticipated in the forseeable future. (i) The relationship of the proposed use to the compre- hensive plan and flood plain management program for the area. VOLUME fPAGE /11 (j) The safety of access to the property in times or flood of for ordinary emergency vehicles. (k) The expected heights, velocity, duration, rate of rise and sediment transport of the flood waters expected at the site. (1) Such other factors which are relevant to the pur- poses of this Ordinance. 7.4 Conditions Attached to Special Exception Permits Upon consideration of the factors listed above and the purposes of this Ordinance, the Board may attach such conditions, to the granting of a Special Exception Permit as it deems necessary to further the purposes of this Ordinance. Among such conditions without limitation because of specific enumeration may be included: (a) Modification of waste disposal and water supply facilities. (b) Limitations on periods of use and operation. ec} Imposition of operational controls, sureties and deed restrictions. (d) Requirements for construction of channel modifica- tions, dikes, levees and other protective measures. eel Flood proofing measures such as the following shall be designed consistent with the flood protection ~ elevation for the particular area, flood velocities, durations, rate of rise, hydrostatic and hydrodynamic forces, and other factors associated with the ''- VOL U1lE _...-r1I"' "P!~"" 4' I / ~ ~,~.~\rJ.:J~ regulatory flood. The Board of Adjustment may ,~ require that the applicant submit a plan or document certified by a registered professional engineer that the flood proofing measures are consistent with the regulatory flood protection elevation and associated flood factors for the particular area. The following flood proofing measures may be required without limitation because of specific enumeration: (1) Anchorage to resist floatation and lateral movement. (2) Installation of watertight doors, bulkheads and shutters. (3) Reinforcement of walls to resist water pressures. (4) Use of paints, membranes, or mortars to reduce seepage of water through walls. (5) Addition of mass or weight to structures to resist floatation. (6) Installation of pumps to lower water levels in structures. (7) Construction of water supply and waste treat- ment systems so as to prevent the entrance of flood waters. (8) Pumping facilities for subsurface external foundation wall and basement floor pressures. (9) Construction to resist rupture or collapse "~''':''T''''''''" .~ y ...~' ,~) ,.\;_~.r.,; . ' - '~.,~~ caused by water pressure or floating debris. (10) Cutoff valves on sewer lines or the elimina- tion of gravity flow basement drains. (11) Elevation of structures and uses to the regula- tory flood protection elevation. SECTION 8.0 DEFINITIONS Unless specifically defined below, words or phrases used in this Ordinance shall be interpreted so as to give them the same meaning as they have in common usage and so as to give this Ordinance its most reasonable application: Easement - A right, either in the public generally on in private entities or persons, to the use of a piece or parcel of land for a special purpose, including the location of utilities, storm drains or access, which right may include the use of the surface, sub-surface and/or the air space over such land. Easement; Maintenance - An easement to provide for the maintainability of the floodway. Easement; Access, Watercourse and Parkway - An easement for access to the floodplain and to provide for the con- servation of waterways and greenways throughout the city. Enaroachment Lines - Limits of obstruction to flood flows. These lines are generally parallel to the stream. The lines are established by assuming that the area landward (outside) of the encroachment lines will be ultimately developed in such a way that it will not be available to VOLUME --;!!j: PAGE-1li.. convey flood flows. If hydraulic efficiency of the floodway is maintained by protecting it against un- necessary encroachments, it will be adequate to convey the regulatory flood without resulting in an increase in flood elevations which would cause damage to existing or future development. Equal Degree of Encroachment - A standard applied to the evaluation of the effects of special exceptions on increases in flood heights. It assumes that an encroach- ment if permitted may confer on all property owners on both sides of the stream an equal right to encroach to the same degree within that reach. Since the factors affecting hydraulic efficiency are usually not uniform within a reach this will usually not result in equal distances between encroachment lines and the sides of the stream. Flood - A temporary rise in stream flow or stage that results in water overtopping its banks and inundating areas adjacent to the channel. Floodway - The channel of a stream and adjacent land areas which are required to carry and discharge the flood water or flood flows of any river or stream associated with the regulatory flood. ~F-Iood Pla~n - That area outside the floodway which is still subjectto inundation by the regulatory flood. VOLill/fE f 'PAGE //S' Flood Proofing - A combination of structural provisions, changes, of adjustment to properties and structures subject to flooding primarily for the reduction or elimination of flood damages to properties, water and sanitary facilities, structures, and contents of build- ings in a flood hazard area. Obstruction - Any dam, wall, wharf, embankment, levee, dike, pile, abutment, projection, excavation, channel rectification, bridge conduit, culvert, building, wire, fence, rock gravel, refuse, fill, structure or matter in, along, across, or projecting into any channel, water- course, or regulatory flood hazard area which may impede, retard, or change the direction of the flow of water, either in itself or by catching or collecting debris carried by such water, or that is placed where the flow of water might carry the same downstream to the damage of life or property. Person - Any natural person, firm, partnership, association, or corporation, but this definition does not include any governmental unit. Reach - A hydraulic engineering term to describe longi- tudinal segments of a stream or river. A reach will generally include the segment of the flood hazard area where flood heights are primarily controlled by man-made or natural obstructions or constructions. In an urban area an example of a reach would be the segment of a ,\'nr Try,,", ~, - '1// ',_._U;Ji..~L.. ~,_i~_';"~-; f/~ -- stream or river between two consecutive bridge crossings. --..,. Regulatory Flood - The regulatory flood is a flood which is representative of large floods known to have occurred generally in the area and reasonably characteristic of what can be expected to occur on a particular stream. The regulatory flood generally has an average frequency in the order of the IOO-year recurrence interval flood determined from an analysis of floods on a particular st4eam and other streams in the same general region. Regulatory Flood Protection Elevation - The elevation to which uses regulated by this Ordinance are required to be elevated or flood proofed. Structure - Anything constructed or erected, on the ground, r- or attached to the ground including, but without limiting the generality of the foregoing: buildings, factories, sheds, cabins, mobile homes, and other similar items. :?,&v~ ~ PASSED AND APPROVED this d{J day of Gct.:~8r, 1973. ATTEST: ':~d Mayor me /'J2/Ur ....