47.5 MB - The Whole Building Design Guide

Table 2-3: Checklist for Building Vulnerability of Flood-Prone Critical Facilities (continued)Vulnerability Sections Guidance ObservationsSite Conditions (continued)(continued)The effects of an upstream dam failure arenot shown on the FIRMs or most flood hazardmaps prepared locally. Although dam failuregenerally is considered an unlikely event, thepotential threat should be evaluated due to thecatastrophic consequences. (Note: owners ofcertain dams should have emergency actionplans geared toward notification and evacuationof vulnerable populations and critical facilities.)Does the surroundingtopography contribute to theflooding at the site? Is therea history of local surfacedrainage problems due toinadequate site drainage?If areas with poor local drainage and frequentflooding cannot be avoided, filling, regrading,and installation of storm drainage facilities maybe required.Given the nature ofanticipated flooding andsoils, is scour around andunder the foundation likely?Has water from othersources entered the building(i.e., high groundwater,water main breaks, sewerbackup, etc.)? Is there ahistory of water intrusionthrough floor slabs or wellfloorconnections? Arethere underground utilitysystems or areaways thatcan contribute to basementflooding? Are therestormwater sewer manholesupslope of window areasor openings that allowlocal drainage to enter thebasement/lower floor areas?Scour-prone sites should be avoided, in part dueto likely long-term maintenance requirements.Flooding that is high velocity or accompanied bywaves is more likely to cause scour, especially onfills, or where local soils are unconsolidated andsubject to erosion.These questions pertain to existing facilities thatmay be impaired by water from sources otherthan the primary source of flooding. The entirebuilding envelope, including below-grade areas,should be examined to identify potential waterdamage.2-94 MAKING CRITICAL FACILITIES SAFE FROM Flooding