data with "all the information FEMA needs to review and evaluate the request. This may involve the requestor’s performing new hydrologic and hydraulic analysis and delineation of new flood plain boundaries and floodways, as necessary.” Details of the required supporting data are listed in 44 C.F.R. § 65.7. Outdated flood maps The U.S. Geological Survey says increased runoff resulting from urban growth generally increases flood hazards to communities and that flood hazard maps based on data before urban growth may no longer be accurate. The U.S. Geological Survey gives the example that construction encroaching into the floodplain narrows the floodplain width thereby increasing the resistance to flow. Consequently, the water is at a higher stage as it flows past the construction causing backwater to flood a larger area upstream. FEMA's computer model image at right "represents the percent chance of flooding at least one time during a 30-year period for a given cell, or location, within the mapped floodplain". Updating flood maps NFIP regulation "Requirement to submit new technical data" says "A community’s base flood elevations may increase or decrease resulting from physical changes affecting flooding conditions. As soon as practicable, but not later than six months after the date such information becomes available, a community shall notify the Administrator of the changes by submitting technical or scientific data in accordance with this part. Such a submission is necessary so that upon confirmation of those physical changes affecting flooding conditions, risk premium rates and flood plain management requirements will be based upon current data." FEMA requires "Copies of the input and output data from the original and revised hydraulic analyses shall be submitted" with the hydraulic analysis supporting revisions to flood maps. A 2015 FEMA website identifies that the U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center's River Analysis System (HEC-RAS) computer program has been adopted for the preparation of studies and restudies for the NFIP. Land use restrictions in floodplains Findings The U.S. Congress finds annual flood losses are increasing at an alarming rate and forms of Federal assistance are often determining factors in the utilization of land and the location and construction of public and of private industrial, commercial, and residential facilities The purpose for such Federal assistance is frustrated where Federal assistance is exposed to flood risks. A U.S. District Court finds that FEMA determinations of which properties are within the regulatory floodplain affects the location