[HISTORY: Adopted by the Town Board of the Town of Alden 9-7-1976 by L.L. No. 4-1976 (Ch. 9A of the 1981 Code). Amendments noted where applicable.]
This local law shall be known as the "Drainage Control Law."
The provisions herein relate to any development which affects the rate or flow of surface water runoff, alters above- or subsurface water tables and aquifers or modifies the quality of above- or subsurface streams.
This chapter is intended to maintain adequate and efficient drainage, to assist in preventing flooding, to promote effective and desirable conservation practices, to maintain natural water resources and to preserve existing public and private property equities.
As used in this chapter, the following terms shall have the meanings indicated:
- A water-bearing rock or soil strata.
- CLOSED DRAINAGE
- A network of artificial conduits and pipes constructed to convey the runoff of natural waters.
- Erie County.
- The actual owner or owners of the land and/or a person, firm or corporation which shall develop or use land within the Town in such a manner that it in any way affects the storm- or surface water drainage characteristics of the property developed or used. The term "developer" shall include municipal, charitable and educational corporations, institutions, associations and governmental agencies.
- Any improved land use, including residential, commercial, industrial, institutional or recreational.
- DRAINAGE EASEMENT
- A permanent right-of-way granted by the owner to the Town or other entity providing unhindered access to the banks and channel of streams and drainage systems.
- DRAINAGE REPORT
- A report entitled "Drainage Study, Town of Alden, August 1966."
- DRAINAGE SYSTEM
- A network consisting of any combination or type of open channels and enclosed artificial facilities employed to convey the runoff of natural waters.
- ENCROACHMENT LIMIT
- The boundary of a maintenanceway easement adjacent to a drainage channel within which no building or structure shall be erected, or trees, bushes or other plantings planted or allowed to grow, which shall interfere with the maintenance of the drainage channel.
- ENFORCEMENT OFFICER
- Town Engineer or other agent of the Town designated by the Town Board.
- FLOW RATE
- The quantity of water which moves past a given point in an increment of time.
- OPEN DRAINAGE
- A network of natural streams, constructed channels and ditches employed to convey the runoff of natural waters.
- PLANNING BOARD
- The Town of Alden Planning Board.
- SOIL MAP
- Soil Interpretations, Town of Alden, August 1974.
- SURFACE WATER
- That portion of natural precipitation which moves across the land surface via channels, ditches, etc., to permanent watercourses.
- The Town of Alden.
- TOWN ENGINEER
- The Town of Alden Town Engineer.
- WATER TABLE
- The level below which the soil is saturated with water.
- Lands and submerged lands commonly called "swamps" or "marshes" which support aquatic or semiaquatic vegetation, plants or brush.
[Amended 12-3-2007 by L.L. No. 4-2007]
Developments shall be protected from flood hazard and inundation by stormwater, springs and other surface waters. The design and construction of drainage systems shall be such that watercourses traversing the development and natural water emanating from within the development will be carried through and off the development without injury to improvements, building sites or buildings existing or to be installed within or adjacent to the tract. Drainage water entering the development shall be received and discharged at locations and as nearly as possible in the manner that existed prior to construction of the drainage facilities within the development. The design of drainage facilities within the development shall be such that they will conform to the ultimate drainage requirements of the land uses within the development watershed. The discharged flow at the downstream area of the development shall be conducted in drainage facilities so that the flow effects shall be restored as near to predevelopment conditions as possible prior to leaving the development area or reasonably distant therefrom.
Drainage easements and additional areas, as dedicated under these provisions, need not be fenced, but shall be identified by monuments acceptable to the Town Engineer, and if directed by the Town Engineer, set at an angle point and at such other locations which allow intervisibility.
Surface waters and drainage, where identified as being significant sources of groundwater replenishment and where such resources are being utilized as a potable water supply, all as determined by the Town Engineer, shall not be revised or altered except by approved permit.
The requirements of the Town of Alden "Law to Prohibit Illicit Discharges, Activities and Connections to Separate Storm Sewer System" and the Town of Alden "Stormwater Management and Erosion and Sediment Control Law" of the Alden Town Code must be followed. Whenever the requirements of this chapter are at variance with the requirements of any other lawfully adopted rules, regulations or ordinances, the most restrictive, or that imposing the higher standards, shall govern.
Except as hereinafter provided, it shall be unlawful for any person, firm, entity or corporation to:
Modify the topography or surface qualities of any area not covered by other Code provisions so that the water retention characteristics of the area are modified, unless the action has been approved by a permit granted as herein provided. Recognized agricultural procedures in areas zoned for such purpose are exempted from the regulations herein defined.
Place, deposit or permit to be placed or deposited any debris, fill, sand, stone or other solid materials of any kind or nature or construction of any kind into or across any stream, ditch, culvert, pipe, watercourse or other drainage system.
Construct and/or place any ditch, pipe, culvert or artificial watercourse of any kind or nature which shall collect and direct the flow of natural surface waters or drainage, or increase in intensity or quantity the flow of surface waters or drainage from paved surfaces, structures, roads or improvements directly into any stream, ditch, culvert, pipe or watercourse or other drainage system unless the action has been approved by a permit as herein provided.
Fill, obstruct, dam, divert or otherwise change or alter the natural or artificial flow of waters or drainage or the intensity or quantity of flow through any stream, ditch, pipe, culvert, watercourse or other improvement or drainage system unless the action has been approved by a permit as herein provided.
The drainage channels for watercourses numerically identified in the Town Drainage Study shall be provided to accommodate not less than the minimum flows indicated in the drainage report. These values shall be independently verified by their users using hydrologic technology recommended herein, and the hydrologic analysis thereof shall become a part of the supporting data of the proposed drainage plans. The minimum flow requirements for the ultimate channel of the watercourses shall be determined in accordance with not less than the following frequencies:
Major watercourses. Major watercourses are defined as those with a tributary drainage area between 20 square miles and four square miles. Such watercourses shall be designed for an average recurrence interval of 50 years in the determination of the ultimate channel.
Secondary watercourses. Secondary watercourses are defined as those with a tributary drainage area of between one and four square miles. Such secondary watercourses shall be designed for an average recurrence interval of 25 years in the determination of the ultimate channel.
Minor watercourses. Minor watercourses and drainage systems are defined as those with one square mile or less of tributary drainage area. Such watercourses and drainage systems shall be designed for an average recurrence interval of 10 years in the determination of the ultimate channel.
The capacity of the channel that will occupy the ultimate drainage easement within the development shall be based upon both the existing degree and anticipated rate of urbanization within the development watershed and the type of development possible under the Zoning Law of the Town, as the same may be modified from time to time. Wherever a development may be located within a watershed undergoing initial stages of urban development, the proposed drainage system shall adequately pass the flows that would develop from continued urbanization within the useful life of the proposed channel improvement or system. Proposed drainage systems within developments located in watersheds that may be in the advanced stages of urbanization shall be designed and constructed to pass the project design flow determined for the ultimate urbanization of the tributary watershed.
Stormwater management systems for new development, amended development or redevelopment sites shall be designed in accordance with the latest requirements of the New York State Department of Environmental Conservation.
The hydraulic design of development drainage systems shall be in accordance with modern standard procedures, endorsed by the American Society of Civil Engineers.
Hydraulic design shall conform to the latest professional manuals dealing with the many facets which constitute a comprehensive drainage system. Reference to manual sources herein are for only the principal features of drainage systems. These do not imply any limitations in the use of such references, but rather should be supplemental with all essential detailed references to assure sound design.
The hydraulic design of closed drainage systems shall conform in basic details to American Society of Civil Engineers Manual of Engineering Practice No. 37 and such applicable manuals that would supplement or integrate advanced and proved hydraulic principles and basic assumptions. Enclosed drainage systems shall be designed to provide complete drainage for all elements within the development and shall include all appurtenances essential for the adequate performance thereof. The size of conduits shall be selected at grades which produce a minimum velocity of three feet per second when flowing full.
The hydraulic design of open drainage systems shall conform in principle and basic details to the United States Bureau of Public Roads Hydraulic Design, Series Nos. 1, 3, 5 and 6, and such commercially published modern open-channel hydraulic references that would in the public interests assure sound design.
A development grading plan similar to the Federal Housing Administration Grading Plan, indicating a contour interval suitable for the map scale, shall be provided to show detailed comprehensive and efficient surface drainage for all lots within and immediately adjacent to the development.
Structural. Catch basins, manholes, inlet structures and other appurtenances placed within the development shall conform to standards approved by the Town Board. The structural design of all drainage appurtenances shall be subject to the approval of the Town Engineer and shall conform to standard specifications adopted by the Town Board.
Channels. The minimum center-line radius of constructed curved channels shall be at least three times the bottom width of the channel for subcritical flow. The minimum bottom width of constructed channels shall be four feet. The creation of excessive numbers of curves in open channels shall be avoided by reason of the increase in friction loss and the potential erosion due to spiral flow. Outer bank protection, especially at the downstream end of the curve and to a lesser degree on the inner bank at the beginning of the curve, may be required by the Town Engineer. Earth channels constructed within the development shall have side slopes of one on four or flatter, unless otherwise approved by the Town Engineer.
Enclosed conduits. Except for adequate natural watercourses, all storm drainage within the development which is capable of being transmitted in a thirty-six-inch diameter pipe shall be carried in an enclosed conduit. This size may be varied, either increased or decreased, according to topographic conditions or an economic analysis of the cost of the conduit against an equivalent open channel, including the occupied land value, provided that the ultimate selection is in the public interest. The minimum conduit size shall be 12 inches in diameter. Manholes shall be provided at all changes in grade and direction. Spacing of manholes and minimum cover of conduit shall conform to standard practice endorsed by the American Society of Civil Engineers. Inverted siphons shall not be permitted except for temporary structures.
All existing obstructions, dams, diversions, construction of any kind, deposits of debris, fill, sand or other solid material, or other alterations or diversions of the natural flow of water or the intensity or quality of flow, through, across or to any stream, ditch, culvert, watercourse or other drainage system, which cause the inundation of real property, buildings or other premises; or, in the opinion of the Town Engineer, constitute an undue burden upon the drainage system or hamper the proper present or future course of development of the drainage system; or, in the opinion of the Town Engineer, presently constitute or in the reasonable foreseeable future will constitute a danger or hazard to the well-being, safety or general welfare of the residents of the Town or any property located therein; or constitute, in the case of wild growth of natural vegetation or brush, an obstruction which may cause flooding, inundation or diversion of water upon other premises; shall be removed or corrected by the owners of the premises upon which said obstruction, dams, diversions, construction deposits or other alterations of the natural flow of water are situated within 60 days after written notice to remove or correct same by the Town Engineer; subject, however, to appeal by such owner to the Town Board within 60 days of such notice, or immediately if determined by the Town Engineer to be an immediate threat to life or property if left unattended.
Easement for enclosed conduits and appurtenances. An easement not less than 20 feet in width, sufficient to contain the enclosed conduit and appurtenances thereof and to provide working space for personnel and equipment for the servicing thereof, shall be indicated on the map of the development and designated as follows: "Drainage Easement to Town of Alden," or to others as deemed appropriate by the Town. Drainage easements for enclosed conduits shall, insofar as possible, be placed along or adjacent to lot boundary lines in a parallel and straight alignment.
Easement for natural watercourses.
Natural major watercourses which traverse a development shall be preserved by an easement of sufficient width, including overbanks, which will adequately pass the project design flow. The gross allowable depth of flow shall not create a flood hazard to existing or proposed developments and improvements. The channel and overbank widths, together with a minimum twenty-foot continuous maintenanceway on each side, shall constitute the encroachment limits with a minimum width as determined by the Town. Wherever such natural watercourses are endowed with significant natural beauty and have adequate capacity, or have been determined to have value for fish and wildlife, the developer may dedicate widths in addition to those required above on the map of the development with the following designation: "Easement to Town of Alden," if so required or agreed upon by the Town.
In natural minor and secondary watercourses which contain insufficient waterway area to convey the flow from the ultimate development, but which may prove deficient only at infrequent intervals and locations, and where minor improvements could provide an adequate channel and still preserve in the main the natural channel beauty or fish and wildlife values, the developer may make such minor channel improvements as are required to provide a channel which would otherwise meet the conditions of these regulations. However, the developer shall dedicate the full width required to contain the ultimate channel, together with a minimum twenty-foot-wide continuous maintenanceway on one side of the ultimate channel. When the water surface exceeds 20 feet in width, the continuous maintenanceway shall be 20 feet wide at each side. The outside of the continuous maintenanceway shall constitute encroachment limits. Additional widths of scenic areas and areas of natural wetlands, which for economic reasons or limited suitability would not warrant improving for urban development, may be dedicated by the developer in addition to those above. Areas offered for dedication to the Town as drainage easements, if considered of special interest to the Town by the Town Board upon review of the Planning Board, may be considered as dedication for municipal purposes for the purpose of § 281 of the Town Law and its authority thereunder.
Easement for constructed channels and appurtenances. Earth channels constructed within the development shall have sufficient easement, dedicated to contain the top width of the channel plus a minimum twenty-foot continuous maintenanceway on one side thereof for channels less than 20 feet in width at the water surface. A twenty-foot continuous maintenanceway shall be provided on both sides of channels with a water surface width greater than 20 feet. The ultimate channel shall meet the flow requirements for the development of the tributary drainage area. The allowable depth of flow to pass the project design flow shall not create a flood hazard to existing and proposed developments and improvements. A minimum of one foot freeboard above the design hydraulic gradient shall be provided to contain the effects of flow transmission factors. The outside of the continuous maintenanceway shall constitute encroachment limits. The easements for constructed channels shall be indicated on the map of the development and designated as follows: "Easement to Town of Alden," or to others as deemed appropriate by the Town.
Before review by the Planning Board of a development plan, the developer shall submit drainage plans with a report containing sufficient data for the Town Engineer to check the feasibility of the drainage system as proposed by the developer. The following data shall be included:
The plan and profile of all drainage systems shall be provided.
Sizes and types of drainage improvements, including special structures, typical sections, easements, width and fencing.
When required, supporting calculations for upstream and downstream channel capacities as they affect water surface levels and backwater within the development. Such calculations shall be supported by such additional survey information as may be required to determine profile and cross section of the upstream and downstream channel reaches of the development under consideration.
A development grading plan prepared to suitable contour intervals with grading details to indicate proposed street grades and elevations, building site elevations and surface elevations at critical points throughout the development, similar to the Federal-Housing-Administration-type grading plan.
The final construction plans for drainage disposal within the development shall conform to the provisions of these regulations, subsequent amendments thereto and any particular conditions as required by the Town Engineer in approving the proposed plans and supporting data thereof. The construction plans for the drainage requirements shall be approved by the Town Engineer prior to the construction of any drainage facilities within the development.
All drainage construction shall be subject to adequate inspection. Any field changes which affect the intent of these provisions shall have the prior approval of the Town Engineer.
Permit applications shall be submitted to the Building Department, together with such supporting information and data as may be required. Such information shall include:
Preliminary review of the application shall be made by the Planning Board within 45 days of the receipt of the required information. Review may require consultation with the applicant and Town Engineer.
Based on definition of the drainage system, the proposed change, the design and construction of the change and the Town Engineer's recommendations, the Planning Board will act within 15 days to refer comments to the Town Board to approve, disapprove or approve conditionally the issuance of a permit. Upon approval or conditional approval by the Town Board, the Town Board shall direct the Building Inspector to issue a permit subject to the following condition:
The Town Engineer shall monitor and approve the drainage change.
Any person, firm, corporation or entity who shall continue any violation beyond the time limit provided for in Subsection A shall be guilty of a violation and, upon conviction thereof, shall be fined in an amount not to exceed $250 for each violation. Each day in which such condition shall continue shall be deemed a separate violation.
Any person, firm, corporation or entity violating any of the provisions of this chapter shall become liable to the Town for any expense or loss or damage occasioned the Town by reason of such violation.
The approval of plans for proposed drainage systems and flood hazard prevention requirements shall not constitute a representation, guaranty or warranty of any kind or nature by the Town of Alden, or by an officer or employee thereof, of the safety, operation, adequacy or intent of the proposed facilities, and shall create no liability upon or cause for action against such public body, officer or employee for any damage that may result from construction pursuant thereto.