Current through Register Vol. 54, No. 44, November 2, 2024
Section 105.201 - Hydraulic capacity(a) A stream enclosure shall be designed and constructed to pass the flows from a flood of 100-year frequency, with no more than a 1.0-foot increase in the 100-year water surface elevation over the water surface elevation of the natural unimpeded 100-year flow, except where the stream enclosure would be located in a floodway which is delineated on a FEMA map in which case no increase in the 100-year water surface elevation will be permitted. The 100-year discharge shall be based upon the degree of development of the contributing watershed projected throughout the lifetime of the structure. The Department may require capacity in excess of that necessary to carry the flows from a 100-year flood if it determines the capacity is necessary to protect the structure or to assure the safety of life and property upstream or downstream of the enclosure.(b) An exception to the criteria of subsection (a) may be approved by the Department if the applicant prepares a risk assessment which demonstrates, and the Department finds, that the structure will not significantly increase the flooding threat to life, property or the environment, and if applicable, is consistent with municipal floodplain management programs adopted pursuant to the National Flood Insurance Program and a FEMA Flood Insurance Study. This information can be obtained from the Department of Community Affairs, Floodplain Management Division, Forum Building, Harrisburg, Pennsylvania 17120.The provisions of this §105.201 adopted August 11, 1978, effective 8/28/1978, 8 Pa.B. 2229; amended September 26, 1980, effective 9/27/1980, 10 Pa.B. 3843; amended October 11, 1991, effective 10/12/1991, 21 Pa.B. 4911.The provisions of this §105.201 amended under the Dam Safety and Encroachments Act (32 P. S. §§ 693.1-693.27); The Clean Streams Law (35 P. S. §§ 691.1-691.1001); section 7 of the act of June 14, 1923 (P. L. 704, No. 294) (32 P. S. § 597); sections 514, 1901-A, 1908-A, 1917-A and 1920-A of The Administrative Code of 1929 (71 P. S. §§ 194, 510-1, 510-8, 510-17 and 510-20); and the Flood Plain Management Act (32 P. S. §§ 679.101-679.601).