09-17-07 Meeting of Drainage and Flooding Committee

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CHAPTER 5 STORM SEWER DESIGN CRITERIA 5.1 GENERAL PROVISIONS Drainage Criteria for development within the City of La Porte, and where applicable within La Porte's Extraterritorial Jurisdiction (E.TJ.) is dependent upon the size and type of development, the conditions within the individual watershed, the conditions or design of the receiving stream, bayou, channel, roadside swale, culvert, or roadway. The basic objective of this policy is to minimize the threat of flooding to areas within the City and its E.TJ. and to minimize the effect of continued development on individual watersheds. 1. The City believes that the best long-term means of accomplishing its objective is a continued program of improvement and extension of the Harris County Flood Control District's system of open channels. This statement recognizes the technical reality that an essential prerequisite to an effective flood control program is a system of open channels capable of carrying storm runoff of any type in Harris County to Galveston Bay without adversely impacting existing urban areas adjacent to the channels. 2. The City recognizes that both District's and City's existing open channel system is, in many instances, inadequate to accomplish the goal of eliminating existing flooding conditions for existing levels of urban development, or for ultimate development in the watershed. 3. The City therefore recommends that where required, certain additional flood control facilities be utilized to supplement the open channel system. Such flood control facilities shall be designed to preclude flooding in areas that do not presently flood and not increase flood levels where flooding now occurs. Specifically, the City supports the use of storm water detention to supplement the open channel system until long-term channel improvements can be completed, or as permanent facilities where additional open channel improvements are not feasible. The result will be that new development will limit or restrict the impact downstream. 5.1.1 All the drainage plans and construction shall meet or exceed the requirements of the City of La Porte, Harris County Flood Control, Harris County, TxDOT, or any other entities having jurisdiction over a facility (i.e. roadway, channel, etc.). 5.1.2 Unless otherwise provided for in these policies, development shall follow the Harris County Flood Control District Criteria Manual for the design of Flood Control and Drainage Facilities in Harris County, Texas. 5.1.3 If application of the policies and criteria contained in this document conflict with the City's duties under the Flood Hazard Prevention Ordinance, the regulations of the Flood Hazard Prevention Ordinance shall apply. 5.1.4 Drainage structures shall be constructed in such locations and of such size and dimensions to adequately serve the development and the contributing drainage area. In new developments, the developer shall provide all the necessary easements and rights-of-way required for drainage structures, including storm sewer and open or lined channels. 5.2 CONSTRUCTION PLAN REQUIREMENTS 5.2.1 A drainage map shall be included in the construction plans. The drainage area map shall include: A. Drainage areas, including areas draining from off-site onto or adjoining the project Stormwater Criteria Page] of] 0