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HomeMy WebLinkAbout06292006 BSC Agenda Item 1 r • • FLOOD PREVENTION AND PROTECTION CITY OF WEST UNIVERSITY PLACE The City of West University Place entered the National Flood Insurance Program(NFIP) in 1978. A condition of participation in the NFIP is adoption and enforcement of a flood damage prevention and protection ordinance and adoption of the most current Flood Insurance Rate Map (FIRM). As a result of tropical storm Allison, the Harris County Flood Control District(HCFCD) and the Federal Emergency Management Agency (FEMA)partnered to create the Tropical Storm Allison Recovery Project(TSARP). One of the primary goals of the project was to re-map all of the FIRM's for Harris County, including the FIRM panels for West University Place. Preliminary maps were published in September 2004. According the HCFCD, 250 appeals and protests were received by FEMA during the 90-day appeal and protest period. Several complicated appeals in the Spring and Cypress Creek watersheds caused delays in the map implementation process, but FEMA is currently finalizing the maps and will be sending out the Letter of Final Determination to the participating communities within the next thirty days. This means that the participating communities will have six (6)months to change their flood prevention and protection ordinances to reflect the new maps. According to correspondence received from the Tropical Storm Allison Recovery Project group, anticipated effective date of the new maps is January 2007. Once the maps are published, flood insurance rates and requirements will be determined based upon the new FIRM's. The proposed new FIRM's will increase the amount of property located in the Special Flood Hazard Area(SFHA) substantially. Under the current FIRM, only a relatively small nine-block area(east of Poor Farm Ditch,between Mercer and Rutgers and Mercer and Vanderbilt) is located in the SFHA, or 100-year floodplain. The preliminary FIRM's have expanded the SFHA five blocks north to University Boulevard and east to Fordham. Also included is a block wide strip from Riley north to Amherst, between College and Auden. The majority of the rest of the City is located in either the Shaded X or X Zones. The previous FIRM map only showed one cross-section where the base flood elevation was delineated at 49'. The proposed new maps are more developed with seven cross- sections, four where base flood elevations are delineated ranging from 47' to 50'. The FEMA and State regulations require that all new construction and substantial improvements to existing construction be built so that the finished floor elevation of the structure meet or exceed the mapped base flood elevation. Several of the surrounding communities have enacted"freeboard"requirements (higher regulatory standards) that require structures to meet or exceed the base flood elevation plus increments in inches between one and two feet. The BSC discussed the implications of this type of regulation for West University Place during several meetings and workshops over the past two years. The concerns they had in enacting this type of requirement centered around the need for fill to elevate structures and the impacts on drainage of surrounding properties, the possible impact to the maximum height requirements for structures, and the hardships that may be created for • • existing structures, especially the "old stock housing" that residents may want to structurally alter, in meeting additional finished floor elevation requirements. At the January 2006 meeting of the BSC, the members voted to recommend adoption of the new FIRM's when published and adoption of the minimum floodplain regulations with no higher regulatory standards until such time that a workshop with City Council could be arranged to discuss these issues. On May 4, 2006, a joint workshop was held with City Council and members of the BSC and ZPC to present an overview of these issues and obtain direction from City Council in order to proceed. The joint workshop on June 29 is to fully orient the members of both commissions as to the areas of responsibility of each group as they pertain to flood prevention issues. • • Issues for Discussion at Joint ZPC / BSC Workshop June 29,2006 The BSC will address the freeboard issue. The BSC will make a recommendation of how much additional freeboard the city should require of new construction above the BFE. The finished floor of houses built in the 100-year flood plain must be built at the BFE elevation for that particular property, as determined with the federal FIRM maps and the federal calculation methods. This BFE must be attached to the plans for the house. As a strawman proposal, the chair proposes no additional freeboard. Some pros on this include: • Additional freeboard above the BFE is at the builder or owner's discretion. • The BFE will change over time as the HCFCD alters the BFE through drainage control projects. These projects will more than likely lower the BFE from time to time, making additional freeboard requirements moot, especially for houses built to earlier BFE levels • The finished floor height at the BFE will allow minimize mitigate houses from flooding due to a 100 year event. • The effect on increased roof heights will be minimal. Some cons are: Some new houses could possibly flood, The homeowner would not be eligible for potential lower flood insurance rates Finally, the CBO could suggest to homebuilders and others that they make a personal decision on what to do with respect to freeboard above the BFE on an individual case basis. The chair asks for an open discussion of this strawman on freeboard. • • The third issue deals with under-house drainage and net fill. The intent of the discussion on under-house drainage is to allow the soil beneath houses built with crawl spaces to dry quickly. This in turn will minimize moisture related decay of construction materials, prevent breeding places for mosquitoes or termites, and to meet certain codes. This is a BSC area issue. As a strawman position, the chair proposes that the current IBC codes be followed on this type of construction. The code requires under-house drainage by gravity or by artificial lift. It also requires under-house ventilation to dry out this area after raining or flooding. Some pros are: The house will last longer without material decay issues to the future homeowner, and Water will not pool for insect problems Some cons are: This will be an additional cost to constructing a house. The chair would like to open this issue for discussion. The second half of the issue of lot drainage concerns net fill. This issue is believed to be a ZPC issue. The ZPC will discuss the meaning of net fill, and the issues of driveway and garage elevations, and additions of construction related clays for foundations. ' • • The fourth issue concerns existing housing. Houses built prior to the enactment of the FIRM maps will be subject to the associated FEMA mandated rules and codes when "substantial" modifications / repairs "alterations" and additions are made to houses with finished floors are below the BFE. The second half of this existing housing issue is the repair of flood damages. Repair costs of these existing houses for flood damages is a cumulative process. The CBO is required to track these costs by each flood-damaged house. Once the cumulative damages exceed a certain percent value of the structure, certain actions are triggered. The CBO has been asked to draft a summary of definitions and requirements that must be met by those modifying an existing house that has a finished floor below the BFE. The determination of the value of such an existing house is a major issue to determine the compliance to this par of the FEMA mandated ordinances. The CBO is requested to propose several valuation methods that will be allowed by the city to determine compliance with the FEA definitions, the basis for applying the definition of substantial, and the cumulative compliance to these rules. The BSC will take this as a strawman position and discuss the CBO's position. The chair would like to open this issue for discussion. • • The chairs of the ZPC and the BSC identified several ancillary issues. These issues more than likely fall into the jurisdiction of the BSC, however, a joint discussion is desired by both the ZPC and the BSC. The first issue is flooding caused to houses by drivers driving through flooded streets creating a wake. The BSC chair proposes a strawman proposal that the BSC works with the Police Department to create a draft ordinance proposal allowing WUP emergency officials to issue stop individuals driving through flooded streets over certain speeds, or no driving including the issuance of citations. In essence to create a no wake zone during times of flooded streets. The second part driving through flooded streets is giving West University officials (including Police, Fire Department and Public Works) the authority to temporarily block certain streets during flooded conditions. The BSC will discuss this option workshop session with the police staff. Blocked storm sewers have been an identified a source of street flooding in the city. The BSC will study and recommend ordinance language of a preventative nature that formally prohibits lawn services from blowing or dumping leaves, etc. into the West U storm sewer system. The ordinance will also formally prohibit construction workers and contractors from allowing dirt and mud from construction sites to remain on the streets that can then enter the storm drains due to rainwater runoff. The CBO will discuss this issue with her staff and propose suggested ordinance language to the BSC. The chairs would like to open these two issues for discussion. flos" Plü1• i� SUBSTANTIAL DAMAGE -means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred. SUBSTANTIAL IMPROVEMENT -means any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before "start of construction" of the improvement. This term includes structures that have incurred "substantial damage", regardless of the actual repair work performed. The term does not, however, include either: (1) Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions or (2) Any alteration of a "historic structure", provided that the alteration will not preclude the structure's continued designation as a "historic structure." NEW CONSTRUCTION -means, for the purpose of determining insurance rates, structures for which the "start of construction" commenced on or after the effective date of an initial FIRM or after December 31, 1974, whichever is later, and includes any subsequent improvements to such structures. For floodplain management purposes, "new construction" means structures for which the "start of construction" commenced on or after the effective date of a floodplain management regulation adopted by a community and includes any subsequent improvements to such structures. LOWEST FLOOR -means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, usable solely for parking or 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 non-elevation design requirement of Section 60.3 of the National Flood Insurance Program regulations. DEVELOPMENT -means any man-made change to improved and unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials. • • Flood Protection and Prevention Issues West University Place Building Height Should the maximum building height in West U be allowed to rise or float with the base flood elevation(BFE) defined by FEMA plus any"freeboard" decided upon by City Council? The zoning ordinance limits the height of buildings in West University Place to a maximum of 35 feet, with lower limits on some structures (Table 7-4b). Height is measured from the standard base level of a site to the highest point of the structure. The standard base level is essentially the elevation of the building site(above sea level) prior to any filling or site preparation. The standard base level is independent of the BFE. Concerns to be considered range from aesthetics and fairness to possible future changes in the BFE resulting from subsidence, on the one hand, to improved drainage on the other. Site Grade-Raising and Drainage What, if any, changes to building site drainage rules should be made? In general, the city code (Sec. 18-56)requires builders to provide for adequate drainage. The rules are intended to ensure proper drainage of the building site itself, to prevent creation of drainage problems on neighboring sites and to avoid interference with natural flow patterns across property lines. A drainage plan must be filed with the building official before issuance of a building permit. New,higher base flood elevations will probably lead to more dramatic grade raising and greater use of pier-and-beam foundations to keep ground-floor levels above the BFE. Updated provisions to protect neighbors and to ensure necessary drainage under raised foundations may be needed.