The Stormwater Administrator shall develop, maintain, implement, and enforce such design or engineering standards, as may be required, that is consistent with the Stormwater Management Program and provides a sound technical basis for the achievement of stormwater management and water quality objectives.
(A) The Stormwater Administrator shall develop and maintain a Stormwater Management Design Manual (Design Manual), approved and adopted by County Council in conjunction with the adoption of the York County Stormwater Management and Sediment Control Ordinance, the terms and provisions of which may be amended from time to time in accordance with the approved Stormwater Management Program, and thereafter amendments thereto independently approved by County Council. The Design Manual shall serve as guidance for the design, construction, and maintenance of facilities which discharge stormwater. The Design Manual shall be used to assist in the design and evaluation of stormwater management facilities in York County. The Design Manual will include, but not be limited to, guidance in selecting environmentally sound practices for managing stormwater. Description of specific techniques and practices shall be included directly or by reference. Use of techniques emphasizing use of natural systems shall be encouraged.
(B) Best management practices (BMPs) can be either structural or non-structural and may be enforced by specific prescription in zoning requirements, subdivision regulations, or on a site-specific basis as may be prescribed to meet Stormwater Management Program objectives. The Design Manual shall be updated periodically to reflect the most current and effective practices and shall be made available to the public.
(C) Although the intention of the Design Manual is to establish uniform design practices, it neither replaces the need for engineering judgment nor precludes the use of information not presented. Other accepted engineering procedures may be used to conduct hydrologic and hydraulic studies or provide for other accepted BMPs if approved by the Stormwater Administrator. The Design Manual will include, but not be limited to:
(1) Guidance and specifications for the preparation of comprehensive stormwater pollution prevention plans (C-SWPPP). Acceptable techniques for obtaining, calculating and presenting the information required in the plans shall be described, as will design conditions which must be accounted for;
(2) Minimum specifications for designing, constructing, and maintaining stormwater management facilities. These specifications shall be established in accordance with current good engineering practices; and
(3) Post-development performance standards for stormwater management facilities and practices. Methodology/criteria for evaluation will include:
(a) Hydrologic and hydraulic evaluations;
(b) Evaluation of best management practices (BMPs); and
(c) Evaluation of downstream impacts.
(Ord. 2819, passed 6-17-19)