For all subdivisions, Town of Austerlitz Code requirements (e.g., Chapter
101, Flood Damage Prevention) related to stormwater management shall be met.
A. Surface water. The applicant may be required by the Planning Board to carry away by pipe or open channel any surface water that may exist either previous to, or as a result of, the subdivision. Such drainage facilities shall be located in the road right-of-way where feasible, or in perpetual unobstructed easements of appropriate width.
B. Drainage structure to accommodate potential development upstream. A culvert or other drainage facility shall, in each case, be large enough to accommodate potential runoff from its entire upstream drainage area, whether inside or outside the subdivision. The Town Engineer shall approve the design and size of the facility based on the anticipated runoff under conditions of total potential development permitted by the Zoning Law in the watershed.
C. Responsibility for drainage downstream. The applicant's engineer shall also study the effect of each subdivision on the existing downstream drainage facilities outside the area of the subdivision. This study shall be reviewed by the Town Engineer. If it is anticipated that the additional runoff incident to the development of the subdivision will overload an existing downstream drainage facility during a ten-year storm, the Planning Board shall notify the Town Highway Superintendent of such potential condition. In such case, the Planning Board shall require alternative drainage measures, if any, until provision has been made for the improvement of said condition off site.
D. Stormwater management design.
(1) Design of the stormwater management system shall be consistent with general and specific concerns, values, and standards of the Town Comprehensive Plan and Code, and applicable county, regional, and state storm drainage control programs, if applicable. Design shall be based on environmentally sound site planning and engineering techniques and shall be designed to result in stormwater runoff rates after development equal to the runoff rates prior to development.
(2) The appropriate technology shall be used to minimize off-site stormwater runoff, increase on-site filtration, encourage natural filtration functions, simulate natural drainage systems, and eliminate off-site discharge of pollutants to ground- and surface water. Such technology may include measures such as retention basins, recharge trenches, porous paving and piping, contour terraces, and swales.
(3) Easements within the subdivision or project site to the ultimate point of stream discharge shall be furnished.
(4) The pattern of drainage shall be included in the grading plans if such plans are required by the Planning Board. This plan shall clearly indicate the direction of flow of all surface water, the location, size, and type of drainage structures, and notation as to the final point of discharge of the surface water. The applicant shall make suitable entrances to private driveways, and driveway culverts shall be installed as approved by the Planning Board.
(5) The Planning Board reserves the right to require special provisions in any case where, in the opinion of the Planning Board, runoff cannot be adequately handled by the drainage structures shown on the typical sections.
(6) All subdivisions shall be laid out to be compatible with the drainage pattern affecting the areas involved, with proper provision to be made for adequate storm drainage facilities. Storm drainage plans shall reflect potential surface runoff within the drainage area after development.
(7) Right-of-way for storm drainage must be sufficient for facilities to handle not only the anticipated discharge from the property being subdivided but also the anticipated runoff that will occur when property at a higher elevation in the drainage basin is developed.
(8) Whenever possible, lots shall be graded so that drainage from the lot flows to a road, municipally owned drainage facility, or natural watercourse, without crossing other lots.
E. Land subject to flooding/compliance with Flood Damage Prevention Law.
(1) In addition, and for all other designated floodplain areas, pursuant to the Town's Flood Damage Prevention Law (Town Code Chapter
101), a floodplain development permit may be required if the proposed subdivision is located in areas of special flood hazard as defined in said Flood Damage Prevention Law. If such is the case, the Planning Board and the applicant shall consult with the Town's Code Enforcement Officer for consideration of, and compliance with, the Flood Damage Prevention Law. The applicant may be required to provide base flood elevation data if such data is not available from other sources. The Planning Board shall consult with the Code Enforcement Officer for purposes of reviewing a proposed subdivision, in order to determine whether proposed building sites will be reasonably safe from flooding. If a proposed building site is located in an area of special flood hazard, all new construction and substantial improvements shall meet the applicable standards as set forth in the Flood Damage Prevention Law.
(2) Land subject to flooding by a 100-year frequency storm or less, or land deemed by the Planning Board to be uninhabitable, shall not be subdivided for residential occupancy, nor for such other uses as may increase danger to health, life or property, or aggravate the flood hazard, but such land within the subdivision shall be set aside for such uses as shall not be endangered by periodic or occasional inundation or improved in a manner satisfactory to the Planning Board to remedy such hazardous conditions.
F. Wetlands. If any wetlands of any kind or size lie within the boundaries of the proposed subdivision or within 100 feet of the proposed subdivision, the applicant shall comply with the requirements of the New York State Freshwater Wetlands Act and the Army Corps of Engineers, if applicable. The final plats shall indicate such compliance prior to approval by the Planning Board.