[Added 5-28-2008 by L.L. No. 2-2008[1]]
[1]
Editor's Note: This local law also repealed former Article XI, Street Specifications, as amended. For current provisions, see Article X of this chapter and Ch. 116, Art. III. In addition, this local law also repealed former Article XII, Other Public Improvements, and Article XIII, Miscellaneous Provisions. For current provisions, see Article XI and Article XII, respectively.
A. 
Removal of spring and surface water. All subdivisions shall be related to the drainage pattern affecting the areas involved, with proper provision to be made for adequate storm drainage facilities. The subdivider may be required by the Planning Board to carry away by pipe or open ditch any spring or surface water that may exist either previous to or as a result of the subdivision. Such drainage facilities shall be located in the street right-of-way, where feasible, or in perpetual unobstructed easements of appropriate width. A culvert or other drainage facility shall, in each case, be of adequate size to accommodate the potential runoff from the entire upstream drainage area, whether inside or outside the subdivision area. The design and size of this facility shall be subject to the approval of the Town Engineer.
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, 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. The Town Engineer shall approve the design and size of the facility based on anticipated runoff from the following storm frequencies under conditions of total potential development permitted by Chapter 150, Zoning, in the watershed:
(1) 
For watersheds with drainage areas of fewer than 320 acres, all structures should be designed to carry the peak runoff for a twenty-five-year storm.
(2) 
For watersheds with drainage areas of between 320 acres and 640 acres, the structures should be designed to carry peak runoff for a fifty-year storm.
(3) 
For watersheds with drainage areas larger than one square mile, all structures should be designed to carry peak runoff for a one-hundred-year storm. The only acceptable method for calculating anticipated runoff shall be computed by the soil cover complex method as utilized by the Soil Conservation Service of the United States Department of Agriculture.
C. 
Responsibility for drainage downstream. The subdivider's engineer shall study and submit a written report of 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 and the Orange County Soil and Water Conservation District. Where it is anticipated that the additional runoff incident to the development of the subdivision will overload an existing downstream drainage facility during a fifty-year storm, provision for the storage of the increased runoff must be made by the developer. (See Appendix B, Stormwater Management, found in the Town Soil Report in the Town offices.)
D. 
Land subject to flooding. Land subject to periodic or occasional flooding or land deemed by the Planning Board to be uninhabitable shall not be platted 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 plat shall be set aside for park purposes in addition to that area which is required by Chapter 150, Zoning.
E. 
Easements. Where a subdivision is traversed by a watercourse, drainageway, channel or stream, there shall be provided a stormwater easement or drainage right-of-way conforming substantially with the lines of such watercourse and such further width or construction, or both, as the Town Engineer may deem adequate to the purpose, but in no case fewer than 30 feet in width and of such width as to encompass the flood of record, plus three feet in elevation. Drainage easements shall be carried from the road to a natural watercourse or to other drainage facilities. When a proposed drainage system will carry water across private land outside the subdivision, appropriate rights must be secured and indicated on the plat.
F. 
House and lot drainage. Drainage of individual lots and dwellings, including footing drains, to assure proper runoff from roofs, driveways and paved surfaces, and ensure positive drainage away from houses, shall be required for Planning Board approval. The installation of such facilities shall be required prior to the issuance of a certificate of occupancy.
A. 
Standards.
(1) 
The drainage system and/or culverts shall be designed in accordance with established engineering principles approved by the Town Engineer. Stormwater management facilities for water quality and control shall be designed in conformance with New York State Department of Environmental Conservation (NYSDEC) stormwater management regulations. The minimum grade of any drainage pipe or culvert shall not be less than 0.05%. No culvert shall be smaller than 18 inches in diameter except by approval of the Town Engineer. Such drainage shall be installed where natural watercourses cross the highways or at locations which warrant drainage. The width of the trench in which the pipe is placed shall be sufficient to permit thorough tamping of the backfill under the haunches and around the pipe. In no case shall the top of any drainage pipe be less than 18 inches below the finished grade of the pavement. Where soft, spongy or unsuitable soil is encountered or where rocks, boulders or ledges are present, such shall be removed and replaced with suitable materials and in a manner as directed by the Town Engineer. The pipe shall be laid to true line and grade on the prepared bed of the trench. The installation shall be in accordance with the standard practice. The backfilling of the trench shall be in accordance with good engineering procedure and as directed by the Town Engineer.
(2) 
All high-density polyethylene pipe and reinforced concrete pipe shall conform to the items covering such in the latest New York State Department of Transportation specifications.
(3) 
Drainage pipe of culverts shall be installed to carry the present requirements of the subdivision as well as that which may reasonably be anticipated from future construction, both from within the subdivision and from adjoining properties which normally drain across the area of the proposed development.
(4) 
The discharge of established natural watercourses and stormwater in open ditches shall be permitted only after specific approval by the Planning Board. If, in its opinion, public health or safety is jeopardized or there is danger of erosion, approval shall be denied. In such case, pipe of the proper kind and size shall be installed or the required paved sluiceways constructed. It shall be the responsibility of the developer to set aside areas for the collection and passage of both natural waters and stormwaters.
(5) 
Catch basins or drop inlets shall be constructed in order that surface water can be intercepted.
(6) 
Headwalls shall be constructed at the inlet and discharge end of the culvert pipe. Culverts shall extend beyond the toe of the embankment or, if carried in easements through or along lots, to a point of no less than 75 feet beyond the rear of proposed residences.
(7) 
If, in the opinion of the Planning Board or Town Engineer, it is necessary to intercept and carry away groundwater to protect the stability of the roadbed, the subdrainage required by the Planning Board shall be installed. Perforated pipe having a minimum diameter of four inches shall be used for such purpose if deemed necessary by the Town Engineer.
(8) 
Alignment of pipes shall be in a straight line between drainage structures.
(9) 
Drain lines shall be placed between the center line of the road and the gutter line and shall, as far as practical, parallel the center line of the road.
(10) 
Drainage structures which are located on state or county highway rights-of-way shall be approved by the State or County Highway Engineer's office, and a letter from said office indicating such approval shall be directed to the Town Planning Board.
(11) 
Surface drainage in gutters shall be limited to the equivalent of that flowing from 1.5 impervious acres; however, where the tributary impervious area exceeds the runoff from one impervious acre, a double-inlet catch basin shall be used.
(12) 
Planned use of natural and other open drainage lines shall be based on an investigation and a written report to the Planning Board as to the downstream conditions anticipated as a result of such use.
(13) 
All open drainage lines (watercourses and ditches) shall be protected by easements guaranteeing to the Town the right of access and power to improve the channels, as well as prohibiting structural or terrain encroachments within the easement except on approval by the Town Engineer. Such easements shall have a minimum width of 30 feet.
(14) 
All open drainage lines and swales shall be protected against erosion by suitable stabilizing materials or construction.
B. 
Inconsistency. Where the technical provisions of § 120-68 and this section are in conflict or disagreement with provisions of other ordinances, specifications or regulations applicable to the subdivision, then the most recently adopted provision shall be utilized unless specifically indicated otherwise by the Planning Board.