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Appendix B
NYSDOT DESIGN REQUIREMENTS AND GUIDANCE
FOR
STATE POLLUTANT DISCHARGE ELIMINATION SYSTEM (SPDES)
GENERAL PERMIT FOR CONSTRUCTION ACTIVITY
May 16, 2014
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TABLE OF CONTENTS
1. BACKGROUND ……………………………………………………………………………..… x
1.1 Permit Applicability ………………………………………………………….……… x
2.0 TECHNICAL INFORMATION ………………………………………………..…………….… x
2.1 DEFINITIONS …………………………………………………….……… x
2.1.1 Disturbance …………………………………………………………...……… x
2.1.2 Area of Disturbance ………………………………………………………… x
2.1.3 Maximum Extent Practicable …………………………….………. x
2.1.4 Routine Maintenance Activities ……... x
2.1.5 Impervious Areas …………………………………………………...………. x
2.1.6 New Development …………………………………………….…………….. x
2.1.7 Redevelopment ……………………………………..……………………….. x
2.1.8 Redevelopment Projects ………………………………….……………….. x
2.1.9 Areas Beyond the Right-of-Way Limits …………………………………. x
2.2 EROSION AND SEDIMENT CONTROL …………………………………………… x
2.2.1 Technical Standards ……………………………………….……………….. x
2.2.2 Erosion Hazard …………………………………………………………….… x
2.2.3 Design of Temporary Sediment Basins ……………………………...…. x
2.3 STORMWATER MANAGEMENT ………………………………………………..…. x
2.3.1 Principles of Green Infrastructure …
2.3.2 Stormwater Management Site Planning and Site Selection – 5 Step Process ……………………………………………………………
2.3.2.1 Step 1: Site Planning to Minimize Disturbed Areas and Impervious Areas …………………………………….
2.3.2.2 Step 2: Calculation of Water Quality Volume for the Site …………………………………………………………….
2.3.2.2.1 Calculation of the Water Quality Volume in Phosphorus Restricted Watersheds ……………..
2.3.2.3 Step 3: Runoff Reduction by Applying Green Infrastructure Techniques and Standard Stormwater Management Practices with Runoff Reduction (RRv) Capacity ………………………………………………………
2.3.2.4 Step 4: Apply Standard or Alternative Stormwater Management Practices to Address Remaining Water Quality Volume ………………………………………………………………….
2.3.2.4.1 Apply Standard Stormwater Management Practices to Address Remaining Water Quality Volume …………………………………………..
2.3.2.4.2 Apply Alternative Stormwater Management Practices to Address Remaining Water Quality Volume (from Areas of Redevelopment) ………..
2.3.2.4.3 Apply a Combination of Standard and Alternative Stormwater Management Practices with Impervious Cover Reduction to Address Remaining Water Quality Volume (from Areas of Redevelopment) ……………………………………..
2.3.2.5 Step 5: Apply Volume and Peak Rate Control Practices ……………………………………………………..
2.3.2.5.1 Stream Channel Protection Volume (Cpv) ……..
2.3.2.5.2 Overbank Flood Control (Qp) ………………….
2.3.2.5.3 Extreme Flood Control (Qf) ………………………
2.3.2.5.4 Downstream Analysis ……………………………..
2.3.2.6 Technical Deviations and Stormwater Crediting
2.3.2.7 Projects That Do Not Require Stormwater Management Practices
2.4 STORMWATER POLLUTION PREVENTION PLAN (SWPPP) ………………… x
2.5 NOTICE OF INTENT …………………………………………………………………. x
2.6 NOTICE OF TERMINATION ……………………………………………………..….. x
2.7 REFERENCES ………………………………………………………………………... x
List of Exhibits
Exhibit 1 - Examples of Routine Maintenance Activities (relative to the SPDES General Permit for Construction Activity) ……………………………………………………... x
Exhibit 2A - Example Impervious and Disturbed Areas for a Highway Widening Segment .… x
Exhibit 2B - Example Impervious and Disturbed Areas for a Bridge Replacement Segment .. x
Exhibit 3 - Percentage of Water Quality Volume Provided by a Standard Stormwater Management Practice with RRv Capacity ……………………………………….…. x
Exhibit 4 - Downstream Analysis …………………………………………………………………. x
ATTACHMENT A - NYSDEC STORMWATER MANAGEMENT DESIGN MANUAL CHAPTER 6: DETAIL DESCRIPTORS TRANSLATED INTO NYSDOT ITEM NUMBERS
1.0 BACKGROUND
Land development projects, including transportation improvement projects, and associated increases in impervious cover can alter the hydrologic response of local watersheds and increase stormwater runoff rates and volumes, contribute to flooding, stream channel erosion, sediment transport, and deposition. This runoff contributes to increased quantities of water-borne pollutants, but can be controlled and minimized through the effective use of best management practices to mitigate the adverse impacts of stormwater runoff.
The New York State Department of Environmental Conservation (NYSDEC) issues the State Pollutant Discharge Elimination System (SPDES) General Permit for Stormwater Discharges from Construction Activity, which establishes the criteria by which construction projects are regulated and are allowed to discharge stormwater. .
1.1 Permit Applicability
Under the current SPDES General Permit for Construction Activity, the Department is required to obtain coverage under the general permit for any project that exceeds 1 acre of soil disturbance (or 5000 square feet in the New York City East of Hudson (EOH) Watershed). The designer should consult the SPDES General Permit for Construction Activity for a list of activities which are ineligible for permit coverage. Among these activities are the following that may apply to Department projects:
1. Construction activities for public roadway and linear utility projects that disturb 2 acres or more of land with no existing impervious cover and where the Soil Slope Phase is identified as an E or F (i.e., 25% or greater slopes, as identified in the County Soil Survey) within a watershed that is tributary to waters of the state classified as AA or AA-s (i.e., 2 acres of disturbance of steep slopes in AA and AA-s watersheds). Existing roadway embankments (including cut and fill slopes) that were built at a 25% or greater slope do not count as steep slopes in this case.
2. Construction projects for which there is a lack or absence of an adequate assessment of impacts to properties listed or eligible for listing on the State or National Register of Historic Places. This permit ineligibility does not apply to projects for which Adverse Effect determinations have been made and the procedures in the Project Development Manual have been followed.
2.0 TECHNICAL INFORMATION
2.1 DEFINITIONS
2.1.1 Disturbance
Under the SPDES General Permit for Construction Activity, the Department is required to assess the requirements for stormwater management practices (SMPs) for any project that exceeds 1 acre of soil disturbance (or 5000 square feet in the New York City East of Hudson (EOH) Watershed). Soil disturbance is defined as “any activity that results in the disruption or exposure of soil”. This soil disturbance definition also includes placing fill and the removal of existing paved areas (such as travel lanes, shoulders, driveways, or parking areas) that exposes soil or disturbs the bottom 6” of subbase material, unless the work in these areas is considered a routine maintenance activity. The 6” threshold applies in areas where the subbase meets the material requirements of Section 304 of the Standard Specifications. If the existing subbase material does not meet this requirement, the area should be considered disturbed area. Temporary disturbances (i.e., disturbances where the ground surface is returned to the pre-existing condition, including vegetation type, soil infiltration capacity, grade and elevation) should also be included in the disturbance calculation. Routine maintenance activities, such as pavement milling and filling, placing shoulder backup material, and ditch cleaning, are not included in the disturbance calculations (see Section 2.1.4.
When determining if the project requires coverage under the SPDES General Permit for Construction Activity, the designer should consider potential design changes during final design and construction such as flattened slopes and contractors operations. It may be beneficial to obtain general permit coverage if the project exceeds 0.9 acre of disturbance during final design. In the event that soil disturbance exceeds one acre after the designer or contractor revises the Stormwater Pollution Prevention Plan (SWPPP), the General Permit coverage must be extended to include the additional acreage.
2.1.2 Area of Disturbance
When calculating the area of disturbance, worksites may be considered non-contiguous if they have logical termini, independent utility, and do not restrict consideration of future transportation projects. For most projects, this results in a separation of approximately 0.25 miles. Projects such as bridge painting, landscaping, sign and light foundation construction, and sign replacement, are typically exempt from SPDES stormwater permit requirements due to the limited soil disturbances and the non-contiguous nature of these projects (see Section 2.3.2.7 for additional discussion of exempt projects). Each worksite is considered independent and separate when calculating the soil disturbance.
For example:
• If no sites are over the 1 acre (or 5000 square feet in the New York City East of Hudson (EOH) Watershed) threshold and the sites are more than 0.25 miles apart, then coverage under the SPDES General Permit for Construction Activity is not required (temporary and permanent erosion and sediment control is still required).
• If only one site is over the 1 acre (or 5000 square feet in the New York City East of Hudson (EOH) Watershed) threshold and the sites are more than 0.25 miles apart and it does not qualify as a maintenance activity (See Section 2.1.4, only that site would require compliance with the permit (all other sites would not qualify for permit coverage).
Note that disturbed areas used for contractor operations, including storage or staging areas within the Right-of-Way (ROW) limits must be included in the Department’s coverage under the SPDES General Permit for Construction Activity and the SWPPP must be revised to include these areas.
2.1.3 Maximum Extent Practicable
The Department's policy is to comply with the requirements of the SPDES General Permit for Construction Activity. The linear nature of highway projects, limited available ROW widths, constraints in urban areas, and the significant number and size of watersheds that may be involved, will provide challenges to meeting the permit requirements. During the preliminary design stage, designers should review the project for possible locations for construction of stormwater management practices to the maximum extent practicable. The following items may be considered impractical due to their extraordinary costs, maintenance difficulty, or substantial social, economic or environmental consequences.
• Pumping stormwater to permanent stormwater management practices.
• Acquisition of sensitive ROW areas including but not limited to taking of residences, relocating businesses, placing stormwater management practices in residential backyards, adverse effects to historic properties, etc.
• Large vault structures for stormwater detention (not including Stormwater Treatment Systems).
• ROW takings initiated solely for stormwater management practices, which would change the scope of the project, and subsequently affect the environmental determination and design schedule.
• Stormwater management practices that exceed 5% of the total project cost for ROW and construction. This limit would not apply in TMDL watersheds, to projects with direct discharges to 303(d) list waterbodies, or projects where post construction practices to address water quantity requirements are required.
• Stormwater management practices that create significant social, economic, or environmental impacts.
• Locations of stormwater management practices that require lane closures of adjacent traffic on high volume (AADT >30,000, high speed (>50mph) highways for routine maintenance of the practice.
• Stormwater management practices that require use of Jurisdictional Wetlands.
• Create a significant encroachment in flood plains or otherwise violate 23CFR 650 or 6NYCRR 502, Floodplain Management. Designers are encouraged to consult with their Regional Hydraulic Engineer and/or MO Hydraulic Engineering Unit for questions about floodplain impacts.
In the event that designers can not meet the requirements of the permit, a meeting should be arranged with the regional DEC office to coordinate acceptable deviations to the technical standards. Any deviations to the technical standards are to be documented in the SWPPP and will require a 60 business day review period for the Notice of Intent (NOI).
2.1.4 Routine Maintenance Activities
In the SPDES General Permit for Construction Activity, “Routine Maintenance Activity” is defined as "activities that maintain the original line and grade, hydraulic capacity, or original purpose of a facility." This includes traditional maintenance activities, such as ditch cleaning and shoulder reshaping, but also activities that meet the definition of routine maintenance that may be part of a larger construction project. Refer to Exhibit 1 for a list of routine maintenance activities. There is no limit on the amount of disturbed area for maintenance activities (i.e., maintenance activities are not included in the disturbance calculations for a project, regardless of the amount of soil disturbance associated with those activities).
In addition, designers should be aware that activities done by maintenance contracts can not categorically be considered "Routine Maintenance Activities". Projects should be reviewed for SPDES stormwater permit requirements independent of NYSDOT project type classification.
Exhibit 1 Examples of Routine Maintenance Activities (relative to the SPDES General Permit for Construction Activity)
|1 |Cleaning and shaping of existing ditches and culverts that maintain the approximate original line and grade, and |
| |hydraulic capacity of the ditch. |
|2 |Streambank restoration projects that do not include the placement of spoil material. |
|3 |Cleaning and shaping of existing ditches that does not maintain the approximate original line and grade, hydraulic |
| |capacity and purpose of the ditch if the changes to the line and grade, hydraulic capacity or purpose of the ditch |
| |are installed to improve water quality and quantity controls (e.g., installing grass lined ditch). |
|4 |Placing of aggregate shoulder backing that makes the transition between the shoulder and the ditch or embankment. |
|5 |Full depth milling and filling of existing asphalt pavements, replacement of concrete pavement slabs, and similar |
| |work that does not expose soil or disturb the bottom 6” of subbase material. |
|6 |Long-term use of equipment storage areas at or near NYSDOT maintenance facilities. |
|7 |Removal of sediment at the edge of the highway to restore a previously existing sheet-flow drainage connection from |
| |the highway surface to the highway ditch or embankment. |
|8 |Existing use of Canal Corp owned upland disposal sites for the canal. |
|9 |Replacement of curbs, gutters, sidewalks, and guiderail posts. |
2.1.5 Impervious Areas
Impervious areas should include concrete or asphalt pavement surfaces, compacted gravel surfaces that are more than 6” in depth, stone filling and rooftops. Soils that are in Hydrologic Soil group D that are compacted as a result of construction activities that have not been restored using Soil Restoration techniques in the New York State Stormwater Management Design Manual, (hence referred to as the Stormwater Management Design Manual) should also be considered impervious.
2.1.6 New Development
The term “New Development” as it relates to the SPDES General Permit for Construction Activity refers to impervious surfaces constructed within the disturbed area, such as widened shoulders, travel lanes or sidewalks that did not exist prior to the pre-construction condition. Temporary pavement placed for maintenance of traffic or pedestrian use, which is to be removed at completion of the contract, is not to be included in the new impervious area. Areas of new development may also be referred to as “New Construction” in the Notice of Intent.
2.1.7 Redevelopment
Redevelopment is reconstruction of any existing impervious surfaces that involves disturbance of the bottom 6” layer of subbase material. These areas include impervious surfaces that are relocated or realigned in close proximity to the existing impervious surface, or replaced in the existing location. Redevelopment is distinguished from new development in that new development refers to construction on land where there had not been previous construction.
For areas undergoing redevelopment, pre-development means the condition just prior to construction. This is based on the assumption that the impervious surfaces have existed for a long period of time.
Although redevelopment activities are generally expected to comply with technical standards contained in the Stormwater Management Design Manual, the project’s SWPPP will be considered to be in conformance with the technical standards if the redevelopment application criteria are met and the design utilizes alternative sizing and selection of stormwater management practices described herein.
The required redevelopment application criteria are:
(1) An existing impervious area is disturbed and then reconstructed as either a pervious or impervious surface, and
(2) There is inadequate space for controlling stormwater runoff from the reconstructed area, or
(3) The physical constraints (e.g., soils, water table, and hydraulic head) of the site do not allow meeting the required elements of the green infrastructure or standard stormwater management practices.
Note that criterion #1 and either #2 or #3 must be met.
The SWPPP for a project that includes redevelopment, with or without increased impervious area, must clearly identify and document the design difficulties and must clearly state that the redevelopment conditions meet the redevelopment application criteria in order to utilize the following alternative sizing and selection of stormwater management practices:
The alternative sizing and selection of stormwater management practices criteria are:
1) For Water Quantity, the following options must be employed:
a) If redevelopment results in no increase in impervious area or changes to hydrology that increases the discharge rate from the site, the ten-year and hundred-year criteria do not apply. This is true because the calculated discharge of pre-development versus post-development flows results in zero net increase. This consideration does not mean that existing quantity controls may be neglected in planned designs. Existing quantity controls must be maintained for post-development flow discharge control.
b) Channel protection for a redevelopment project is not required if there is no increase in impervious area or changes to hydrology that increase the discharge rate. This criterion is not based on a pre- versus post-development comparison. However, for a redevelopment project this requirement is relaxed. If the hydrology and hydraulic study shows that the post-construction 1-year 24-hour discharge rate and velocity are less than or equal to the pre-construction discharge rate, providing 24-hour detention of the 1-year storm to meet the channel protection criteria is not required.
c) If the redevelopment results in an increase in the total impervious area and subsequently increased discharge rate, apply quantity controls for the increased discharge. If the redevelopment results in modified hydrology or flow due to discharge to other sub-watersheds, slope change, direct channelization, curb-line modification, etc., apply quantity controls for the increased discharge.
2) For Water Quality, the following options must be employed:
a) The plan proposes a reduction of existing impervious cover by a minimum of 25% of the total disturbed, impervious area. A reduction in site imperviousness will reduce the volume of stormwater runoff, thereby achieving, at least in part, stormwater criteria for both water quality and quantity. The final grading of the site should be planned to minimize runoff contribution from new pervious area onto the impervious cover. Effective implementation of this option requires restoration of soil properties in the newly created pervious areas. Soil restoration is achieved by practices such as soil amendment, deep-ripping, and de-compaction (See the Stormwater Management Design Manual, Section 5.1.6 Soil Restoration).
b) The plan proposes that a minimum of 25 % of the water quality volume (WQv) from the disturbed, impervious area is captured and treated by the implementation of standard practices or reduced by application of green infrastructure techniques. For all sites that utilize structural stormwater management practices, these practices should be targeted to treat areas with the greatest pollutant generation potential (e.g. parking areas, service stations, etc.). If redevelopment results in the creation of additional impervious area, treatment would be required for 25% of the existing impervious area, plus 100% of the additional impervious area. As with design of any practice, sizing of structures should be based on all areas contributing to the stormwater management practice. Redevelopment, which reconstructs a portion of the site, may choose diversion or flow splitters to be able to size the control structures for the reconstructed area only. For all sites that utilize green infrastructure techniques, a proposed plan is effective when runoff is controlled near the source and managed by infiltration, reuse, and evapotranspiration.
c) The plan proposes the use of alternative practices to treat 75 % of the water quality volume from the disturbed, impervious area as well as any additional runoff from tributary areas that are not within the disturbed, impervious area.
d) The plan proposes a combination of impervious cover (IC) reduction and standard and/or alternative practices that provide at least two of the above methods, as described in Section 2.3.2.4.3.
If there is an existing stormwater management practice located on the site that captures and treats runoff from the impervious area that is being disturbed, the water quality volume treatment option selected must, at a minimum, provide treatment equal to the treatment that was being provided by the existing practice(s) if that treatment is greater than the treatment required by options a) through d) above.
2.1.8 Redevelopment Projects
A redevelopment project is one that undergoes redevelopment. The project area can be entirely under redevelopment or the project area can be a combination of redevelopment and new development. Meeting the RRv criteria is not required for redevelopment activities that meet the redevelopment application criteria in Section 2.1.7.
2.1.9 Areas Beyond the Right-of-Way Limits
Many areas adjacent to the highway are impervious, particularly in urban areas. Common examples are driveways and parking lots adjacent to the highway boundaries. Untreated stormwater from these offsite areas are often intercepted by the linear highway drainage facilities. These areas should not be included in the Water Quality Volume Calculations unless the area is disturbed by construction activities. Drainage areas beyond the highway ROW that drain through the project site via streams, ditches, and other drainage facilities (often through a culvert) should not be included in the Water Quality Volume for the project.
When considering where to locate permanent stormwater management practices, the designer's first objective should be to capture and treat stormwater runoff from the highway and other impervious surfaces within the highway ROW limits. Because of the existing ground slopes, surface drainage and the depth of the closed drainage system within the project limits, it may be infeasible to capture and treat enough stormwater runoff within the highway ROW to meet stormwater permitting requirements. In this case, the designer should investigate the feasibility of treating the runoff from the impervious areas outside of the ROW that drain onto the ROW. See Exhibit 2 for a depiction of the disturbed area, impervious areas, and off-site areas.
Exhibit 2
[pic]
2.2 EROSION AND SEDIMENT CONTROL
2.2.1 Technical Standards
Under the SPDES General Permit for Construction Activity, the NYSDEC has adopted the “New York State Standards and Specifications for Erosion and Sediment Control” (i.e., The Blue Book) as the design standards for erosion and sediment control. The Department has issued separate specifications and standard details for erosion and sediment control (Section 209 and the Standard Sheets), which conform to the NYSDEC standards or provide equivalent performance. Designers should utilize the existing standard sheets and specifications developed by the Department. The Department’s standard sheets and specifications are considered to be in compliance with the NYSDEC standards and do not require a 60 business day review.
2.2.2 Erosion Hazard
Designers should consult HDM Chapter 9, Soils, Walls, and Foundations, for information to be included in the plans and SWPPP regarding soil erosion hazard.
2.2.3 Design of Temporary Sediment Basins
Soils made bare during construction have reduced infiltration capacity because vegetation has been removed. As a result, runoff volume from bare soil surfaces is greater than that from vegetated surfaces. In fact, the amount of runoff during construction can be four times the amount of runoff from the same site in the post-construction condition, and in some cases, the runoff from a 2-year, 24-hour storm event during construction can exceed the post-construction runoff from a 25-year, 24-hour storm event. Consequently, sediment basins used for detention of sediment-laden runoff during construction need to be larger than a permanent post-construction stormwater management practice designed for the same design storm.
Sediment basins should be designed in accordance with the Standard and Specifications for Sediment Basins in Section 5 of the New York Standards and Specifications for Erosion and Sediment Control. Sizing of the basins should be done using the Modified Universal Soil Loss Equation (MUSLE), found in Appendix A of the New York Standards and Specifications for Erosion and Sediment Control.
2.3 STORMWATER MANAGEMENT
Permanent stormwater management practices may be required for any project that requires coverage under the SPDES General Permit for Construction Activity. The locations, sizes, and number of permanent practices is based on the amount of impervious surface created, soil disturbances within the project limits and the Water Quality Volume (WQv) and water quantity volumes and/or flow rates generated by these surfaces. Designers should determine the Water Quality Volume required to be treated as a result of the project impacts, then locate required practices to provide necessary treatment.
The designer is to consider SPDES stormwater permitting requirements during project scoping, preliminary design, and final design. The requirements under the SPDES General Permit for Construction Activity include designing appropriate erosion and sediment control measures, and, when applicable, detaining the 1-year, 24-hour storm event, attenuating the peak flows from the 10-year, 24-hour and 100-year, 24-hour storm events, and establishing water quality treatment measures. These elements may require designers to acquire additional ROW to accommodate these measures. In addition, many elements of the Design Report and project plans will be used to create the Stormwater Pollution Prevention Plan (SWPPP), which must be developed before submitting a Notice of Intent (NOI) to the NYSDEC prior to the “Plans, Specifications and Estimate” (PS&E) submission.
Under the SPDES General Permit for Construction Activity, the NYSDEC has adopted the “New York State Stormwater Management Design Manual,” (Stormwater Management Design Manual) as the design standards for permanent stormwater management practices. Designers should utilize this document for information regarding the design and implementation of permanent stormwater management practices. This manual is available on the NYSDEC website at: . A link has also been provided on the Department’s Stormwater Webpage at: .
The current Stormwater Management Design Manual includes a requirement to incorporate what is known as green infrastructure principles into the project planning and design process. Green Infrastructure is a concept that integrates site planning, land development and stormwater management with protection of the environment, and involves the use of a suite of techniques to preserve (as much as possible) preconstruction hydrology and water quality through small-scale, distributed structural and non-structural practices. Green Infrastructure is discussed in greater detail in the following section.
The designer should consult with maintenance, construction, geotechnical, hydraulic engineer, environmental, and landscape staff when selecting stormwater management practices. Early consultation with NYSDEC staff is also recommended, particularly if the design will require technical deviation or otherwise will not meet the technical standards.
2.3.1 Principles of Green Infrastructure
As it applies to stormwater management, the term green infrastructure (also known as Low Impact Development or LID) includes a wide array of practices to manage and treat stormwater, maintain natural hydrology and ecological function by infiltration, evapotranspiration, capture and reuse of stormwater, and establishment of natural vegetative features. On a regional scale, green infrastructure is the preservation and restoration of natural landscape features, such as forests, floodplains and wetlands, coupled with policies such as redevelopment that reduce overall imperviousness in a watershed. On the local scale, green infrastructure consists of site-specific practices and runoff reduction techniques. Such practices result in runoff reduction and/or establishment of habitat areas with significant utilization of soils, vegetation, and engineered media rather than traditional collection, conveyance and storage structures. These practices are discussed in Sections 2.3.2.1 and 2.3.2.3.
Green Infrastructure can achieve stormwater control through the creation of a hydrologically functional landscape that replicates a natural hydrologic regime. This can be achieved by:
• Minimizing stormwater impacts by reducing imperviousness, conserving natural resources, maintaining natural drainage courses, reducing the use of pipes and minimizing clearing and grading
• Providing runoff storage measures dispersed uniformly throughout a site with the use of a variety of retention, detention, and runoff practices
• Maintaining predevelopment time of concentration by strategically routing flows to maintain travel time and control the discharge
The green infrastructure approach for stormwater management reduces a site’s impact on the aquatic ecosystem through the use of site planning techniques, runoff reduction techniques, and certain standard stormwater management practices. The objective is to replicate pre-development hydrology by maintaining pre-construction infiltration, peak runoff flow, discharge volume, as well as minimizing concentrated flow by using runoff control techniques to provide treatment in a distributed manner before runoff reaches the collection system. This approach offers a distinct advantage over conventional stormwater infrastructure by reducing the production of runoff and the need for collection, storage, and treatment.
Green infrastructure techniques are highly effective when used to address stormwater runoff from smaller, more frequent storms. As rainfall amounts and intensity increase, pervious surfaces become less capable of infiltrating runoff and their peak flow reduction “benefits” diminish. Thus, runoff reduction is not generally applied to larger storms, but can be used to reduce runoff to conventional Stormwater Management Practices (SMPs) used to detain stormwater to meet water quantity requirements (See Section 2.3.2.5.1 Stream Channel Protection Volume (Cpv)).
A summary of the green infrastructure planning tools and runoff reduction techniques can be found in Sections 2.3.2.1 and 2.3.2.3. The green infrastructure planning tools presented in Section 2.3.2.1 are practices that indirectly result in runoff reduction. Consequently, a water quality volume reduction is realized when calculating the percentage of impervious area in the water quality volume formula shown in Section 2.3.2.2. The green infrastructure techniques presented in Section 2.3.2.3 are practices for which runoff reduction is quantified.
Although a highway right-of-way is an altered landscape with significantly modified drainage patterns to meet the needs of the transportation infrastructure, site planning strategies must be considered when assessing the need for stormwater management on a project. Hydrologic goals and objectives have been incorporated into the site planning process.
2.3.2 Stormwater Management Site Planning and Design Using Green Infrastructure – A 5 Step Process
This process is intended to guide the designer through steps that maintain pre-construction hydrologic conditions of the site by application of environmentally-sound development principles, such as Green Infrastructure, as well as treatment and control of runoff discharges from the site.
Stormwater management using green infrastructure is summarized in the five step process described herein. Designers are required to adhere to the five step process when developing a SWPPP and that the SWPPP documents compliance with this process.
The five steps include:
1. Site Planning to Minimize Disturbed Areas and Impervious Areas,
2. Calculation of the Water Quality Volume for the Site,
3. Runoff Reduction by Applying Green Infrastructure Techniques and Standard Stormwater Management Practices with Runoff Reduction (RRv) Capacity,
4. Apply Standard or Alternative Stormwater Management Practices to Address Remaining Water Quality Volume, and
5. Apply Volume and Peak Rate Control Practices.
2.3.2.1 Step 1: Site Planning to Minimize Disturbed Areas and Impervious Areas
In Step 1, the designer must use practices listed below to protect natural resources and utilize the hydrology of the project site when designing the project. The Preservation of Natural Resources Practices includes these planning strategies:
1) Preservation of Undisturbed Areas - Delineate and avoid undisturbed forests, native vegetated areas, riparian corridors, wetlands, and natural terrain.
2) Preservation of Buffers - Define, delineate and maintain naturally vegetated buffers along perennial streams, rivers, shorelines and wetlands.
3) Reduction of Clearing and Grading - Limit clearing and grading to the minimum amount needed for roads, driveways, foundations, utilities and stormwater management practices.
4) Locating Development in Less Sensitive Areas - Avoid sensitive resource areas such as
floodplains, steep slopes, erodible soils, wetlands, mature forests and critical habitats by
locating development to fit the terrain in areas that will create the least impact.
5) Open Space Design - Use clustering, conservation design or open space design to reduce impervious cover, preserve more open space and protect water resources.
6) Soil Restoration - Restore the original properties and porosity of the soil by deep till and amendment with compost to reduce the generation of runoff and enhance the runoff reduction performance of stormwater management practices. Note: Areas compacted by machinery that are not intended to be permanently compacted must meet the requirements in Table 5.3 in of the Stormwater Management Design Manual. If these requirements are not met, the compacted areas must be assumed to have a Hydrologic Soil Group (HSG) designation one level less permeable than pre-development conditions for the hydrologic analysis. Compacted HSG D soils should be considered impervious.
If the designer is able to document in the SWPPP that undisturbed areas have been preserved, that existing buffers have been preserved, and that clearing and grading have been minimized as much as practicable, the area in the Water Quality Volume calculation in Step 2 can be the project’s disturbed area. If these strategies cannot be sufficiently employed, the area in the Water Quality Volume calculation in Step 2 will be more than the project’s disturbed area. For example, if the project design includes a removal of an existing riparian buffer, then the drainage area to that buffer should be included in the “area” calculation in Step 2.
The designer must then consider practices to reduce impervious cover when designing the project. The Reduction of Impervious Cover Practices include:
1) Roadway Reduction - Minimize roadway widths and lengths to reduce site impervious area
2) Sidewalk Reduction - Minimize sidewalk lengths and widths to reduce site impervious area
3) Driveway Reduction - Minimize driveway lengths and widths to reduce site impervious area
4) Cul-de-sac Reduction - Minimize the number of cul-de-sacs and incorporate landscaped areas to reduce their impervious cover.
5) Building Footprint Reduction - Reduce the impervious footprint of residences and commercial buildings by using alternate or taller buildings while maintaining the same floor
to area ratio.
6) Parking Reduction - Reduce imperviousness on parking lots by eliminating unneeded spaces, providing compact car spaces and efficient parking lanes, minimizing stall dimensions, using porous pavement surfaces in overflow parking areas, and using multi-storied parking decks where appropriate.
Note: Inclusion of this list does not suggest that impervious surfaces should be reduced or minimized beyond accepted safety standards (e.g., AASHTO standards).
The SWPPP must include an evaluation of all the green infrastructure planning measures as they apply to the project site. This evaluation process requires the following information:
1. Develop a map that identifies natural resource areas and drainage patterns; including but not limited to the following (that will routinely be included in a SWPPP):
a. Wetlands
b. Waterways
c. Buffers (stream, wetland, forest, etc.)
d. Floodplains
e. Forest, vegetative cover
f. Critical areas
g. Topography (contour lines, existing flow paths, steep slopes, etc.)
h. Soil (hydrologic soil groups, highly erodible soils, etc.)
i. Bedrock, significant geology features
2. Develop strategies for protection and enhancement of natural resources
a. Preserve natural features
b. Utilize natural features to preserve the natural hydrology
c. Maintain natural drainage design points
d. Maximize retention of forest cover and undisturbed soils
e. Avoid erodible soils on steep slopes and limit mass grading
3. Reduce the impacts of development by reducing impervious surfaces
4. Demonstrate that all reasonable opportunities for preserving natural conditions of the site are employed to minimize the runoff and maintain the pre-construction hydrology
2.3.2.2 Step 2: Calculation of the Water Quality Volume for the Site
The Water Quality Volume is the volume of stormwater generated by the project that should be captured and treated within the project limits. This step is intended to derive a Water Quality Volume prior to the application of Green Infrastructure design techniques to reduce water quality volumes, as shown in Step 3. Treatment of the Water Quality Volume (WQv) is intended to capture and treat 90% of the average annual stormwater runoff volume. The designer should first determine the WQv required to be treated for the project in its entirety. In this step, the designer is not required to break up this volume for each watershed or drainage area. The intent is to determine a volume to be treated for the entire project.
Once the preliminary site design is known, impervious areas are defined, and drainage areas are delineated, the designer should calculate the water quality volume. This shall be termed the Initial Water Quality Volume (WQv(Initial)). This calculation of WQv will have to be revised after green infrastructure techniques are applied.
The Water Quality Volume should be calculated by taking a weighted average of the New Development and Redevelopment areas. The goal is to treat 100% of the WQv for the New Development areas and 25% of the WQv for the Redevelopment areas.
The following equation can be used to determine the Initial WQv (in acre-feet of storage):
WQv(Initial) = (N + 0.25R)(P)(Rv)(A) / 12
Where:
WQv(Initial) = Initial Water Quality Volume (in acre-feet).
P = 90% Rainfall Event Number (See figure 4.1 in the Stormwater Management Design Manual)
Rv = 0.05 + 0.009(IC), the runoff coefficient, where impervious cover, IC, is percent impervious area within the disturbed area (a minimum Rv of 0.2 should be used).
IC = New Development Impervious Area + Redevelopment Impervious Area X 100
Entire Project Disturbed Area
A = The total disturbed area for the entire project (in Acres) (The area may be greater than the disturbed area, depending on the satisfaction of the requirements in Step 1.)
N = New Development Impervious Area
Total Impervious Area (New + Redevelopment)
R = Redevelopment Impervious Area
Total Impervious Area (New + Redevelopment)
The designer should remember that for activities considered to be Routine Maintenance Activities as defined in Section 2.1.4, the disturbed area is not to be included in the Water Quality Volume calculation.
To convert the WQv to cubic-feet, multiply by 43,560. To convert from cubic-feet to cubic-meters, multiply by 0.02831.
2.3.2.2.1 Calculation of the Water Quality Volume in Phosphorus Restricted Watersheds
For projects in Phosphorus Restricted Watersheds (New York City EOH watershed, Greenwood Lake watershed, and Onondaga Lake watershed), the Water Quality Volume equals the estimated runoff volume (acre-feet) resulting from the 1-year, 24-hour design storm, using the following equation:
WQv(Initial) = (N + 0.25R)( PPhos)(Rv)(A) / 12
Where:
WQv(Initial) = Initial Water Quality Volume (in acre-feet).
PPhos = Rainfall from the 1-year, 24-hour design storm (See figure 4.2 in the Stormwater Management Design Manual)
Rv = 0.05 + 0.009(IC), the runoff coefficient, where impervious cover, IC, is percent impervious area within the disturbed area (a minimum Rv of 0.2 should be used).
IC = New Development Impervious Area + Redevelopment Impervious Area X 100
Entire Project Disturbed Area
A = The total disturbed area for the entire project (in Acres) (The area may be greater than the disturbed area, depending on the satisfaction of the requirements in Step 1.)
N = New Development Impervious Area
Total Impervious Area (New + Redevelopment)
R = Redevelopment Impervious Area
Total Impervious Area (New + Redevelopment)
This WQv calculation for enhanced phosphorus treatment is considered to be suitable for both storage and flow-through systems and applicable to drainage areas that range from highly impervious to highly pervious.
2.3.2.3 Step 3: Runoff Reduction by Applying Green Infrastructure Techniques and Standard Stormwater Management Practices with Runoff Reduction (RRv) Capacity
In Step 3, green infrastructure techniques and certain standard SMPs are to be used to address stormwater runoff to avoid, reduce and manage the impacts of stormwater runoff by using natural features and runoff reduction practices to slow down the runoff, promote infiltration and evapotranspiration, and consequently minimizing the need for larger structural practices.
The reduction of the total Water Quality Volume by application of green infrastructure techniques and SMPs to replicate pre-development hydrology is called the Runoff Reduction Volume (RRv) and is best achieved through the reduction of the impervious surface area and minimization of disturbed area. This is particularly beneficial when pre-development soils possess significant infiltration capacity and are used to reduce runoff volume. This section presents a series of green infrastructure principles and practices that can be incorporated in the site design to allow for management of runoff, promote groundwater recharge, increase losses through evapotranspiration and imitate the preconstruction hydrology, resulting in reduced water quality volume. The required elements of the design of the green infrastructure practices can be found in Chapter 5 of the Stormwater Management Design Manual. Deviation from these requirements must be documented and justified in the SWPPP.
The strategies for runoff reduction fall under two general methods. The first group of practices includes site design techniques that a designer could factor in by subtracting areas from the total site area, resulting in reduced WQv and Channel Protection Volume (CPv), and includes (some of these practices are not appropriate for highway projects, but are included here for informational purposes):
1. Conservation of natural areas - Pre-development hydrologic and water quality characteristics of undisturbed natural areas, stream and wetland buffers can be retained by restoring and/or permanently conserving these areas on a site.
2. Sheetflow to riparian buffers or filter strips - Undisturbed natural areas, such as forested conservation areas and stream buffers or vegetated filter strips and riparian buffers, can be used to treat and control stormwater runoff from some areas of a development project.
3. Tree planting /tree pit - Trees can be planted or conserved to reduce stormwater runoff, increase nutrient uptake, and provide bank stabilization. Trees can be used for applications such as landscaping, stormwater management practice areas, conservation areas and erosion and sediment control.
4. Disconnection of rooftop runoff - Runoff from residential rooftop areas and upland overland runoff flow can be redirected to designated pervious areas to reduce runoff volumes and rates.
5. Stream daylighting for redevelopment activities – Culverted or piped streams can be daylighted to restore natural habitats, better attenuate runoff by increasing the storage size, promoting infiltration, and help reduce pollutant loads. Stream daylighting can be used as an impervious area reduction credit for redevelopment activities.
Note: The first group of practices cannot be used to reduce the WQv if the area (A) used in the WQv calculation is equal to the project’s disturbed area.
The second group of green infrastructure practices provides runoff reduction by storage of runoff volume, thereby reducing the WQv and Cpv, and includes (some of these practices are not appropriate for highway projects, but are included here for informational purposes):
1. Vegetated open swale - Properly designed vegetated channels can be used instead of constructing underground closed drainage or concrete open channels to increase time of concentration, reduce the peak discharge, and provide infiltration. (This category of practice does not include dry or wet swales.) A vegetated swale can be used where the contributing drainage area is less than 5 acres and when the WQv peak flow from the contributing drainage area is less than 3 cubic feet per second (see appendix B in the Stormwater Management Design Manual to determine WQv peak flow rates). For a properly designed vegetated swale, the following runoff reductions in the computed WQv may be applied to the water quality volume of the swale’s contributing drainage area:
• Hydrologic Soil Group A and B soils – 20% (This means that for a certain water quality volume draining to a vegetated swale, 20% of that volume can be reduced from the project’s total WQv to help meet the Runoff Reduction Volume requirement. It should also be noted that for a dry swale (with everything else being the same, including location, drainage area, and soil type), 40% of the WQv can be used to reduce the project WQv, (i.e., twice as much WQv can count toward meeting the Runoff Reduction Volume requirement if a dry swale is constructed instead of a vegetated swale.)
• Hydrologic Soil Group C and D soils – 10%
• Modified Hydrologic Soil Group C and D soil – 15%-12% (to take this credit, the soil modifications must be in accordance with Soil Restoration in Chapter 5 of the Stormwater Management Design Manual).
(Page 5-60 in the Stormwater Management Design Manual should be consulted for other important design criteria for the vegetated open swale.)
2. Rain garden - Small volumes of stormwater runoff can be managed and treated using a conditioned planting soil bed and planting materials to filter runoff stored within a shallow depression. For a properly designed rain garden, the full WQv for the contributing drainage area can be credited towards the runoff reduction volume. Sizing criteria for a rain garden can be found on pages 5-79 and 5-80 in the Stormwater Management Design Manual.
3. Green roof – Stormwater runoff can be captured by a layer of vegetation and soil installed on top of a conventional flat or sloped roof. The rooftop vegetation allows evaporation and evapotranspiration processes to reduce volume and discharge rate of runoff entering conveyance system.
4. Stormwater planter - Small landscaped stormwater treatment devices can be designed as infiltration or filtering practices. Stormwater planters use soil infiltration and biogeochemical processes to decrease stormwater quantity and improve water quality.
5. Rain tank/Cistern - Stormwater runoff can be captured and stored to be used for irrigation systems or filtered and reused for non-contact activities.
6. Porous Pavement - Pervious types of pavements can provide an alternative to conventional paved surfaces, designed to infiltrate rainfall through the surface, thereby reducing stormwater runoff from a site and providing some pollutant uptake in the underlying soils. The storage bed beneath the pavement can be designed to manage runoff from areas other than the porous pavement above it, or can be designed with additional storage to meet the Channel Protection Volume requirement. For porous pavement with a properly designed underground reservoir, the full WQv for the contributing drainage area can be credited towards the runoff reduction volume. If there is no reservoir, the area of the porous pavement may be considered a pervious surface, thereby reducing the WQv.
Note: It is necessary to calculate the drainage areas to the practices listed in the second group of practices to determine reductions in WQv allowed.
The following basic principles must be applied to all green infrastructure design applications:
• Each green infrastructure technique must be appropriately sized for its contributing drainage area.
• Contributing drainage areas, depending on final grading, flow path, impervious cover disconnection, and varying levels of management of the flow, may require sub-catchment delineation.
• For all green infrastructure techniques that involve infiltration, soil infiltration testing is required. Testing must be performed at the proposed practice site and follow the requirements in Appendix D of the Stormwater Management Design Manual.
• For all green infrastructure techniques that involve infiltration, adequate separation distance from ground water table (typically three feet, or four feet above sole source aquifers) and a reasonable drawdown time (typically 0.5 inch/hour minimum) must be met.
• Green infrastructure techniques with storage capacity (i.e., volume reduction practices) that are sited downstream from the developed areas must be sized for contributing areas (pervious and impervious covers), or sized for rainfall by run on.
• Green infrastructure techniques without storage capacity (i.e., area reduction practices) that are sited downstream from the developed areas must be sized for receiving runoff from a maximum contributing area (pervious and impervious covers).
• Areas of green infrastructure techniques that do not receive runoff from developed areas (i.e., Preservation of Natural Resources Practices) can be subtracted from the contributing area of the downstream SMP for WQv calculation. The Rv of the SMP is calculated based on the pervious and impervious cover of the remaining contributing areas.
• If any other calculation methods are utilized (e.g. TR-55), all the contributing areas and related practices must be modeled according to the requirements of the selected method.
• All green infrastructure practices must be designed for overflow and safe passage of storms greater than the design capacity of the system and conveyed to SMPs designed for quantity controls.
• A drainage layer shall be incorporated in most practices to enhance structural integrity, storage, drainage, and infiltration and may not be neglected.
There are SMPs that are considered “standard” as per the Stormwater Management Design Manual and promote infiltration to reduce runoff volumes, and therefore, can be used to meet the Runoff Reduction Volume requirement. These practices are called “standard SMPs with RRv capacity”, and include:
• Infiltration Practices
• Bioretention Practice
• Dry Swale
A designer can apply the percentages of WQv provided by the standard SMP shown in Exhibit 3 towards meeting the RRv sizing criteria, provided the design of the practice complies with the required elements in Chapter 6 of the Stormwater Management Design Manual.
Exhibit 3 - Percentage of Water Quality Volume provided by a Standard Stormwater Management Practice with RRv Capacity
|SMP |RRv Capacity (% of WQv provided by practice) |
|Infiltration Practices |90%* |
|Bioretention Practice |80% in HSG A and B (without underdrain) |
| |40% HSG C and D (with underdrain) |
|Dry Swale |40% in HSG A and B |
| |20% in HSG C and D |
* This means that 90% of the WQv draining to the infiltration practice can be applied to meeting the Runoff Reduction Volume requirement. The remaining 10% of the WQv can be applied to meeting the WQv requirement in Section 2.3.2.4.1.
If the standard SMPs with RRv capacity listed above are going to be used to address the RRv criteria, the practices must be designed to capture runoff near the source. By applying a combination of green infrastructure techniques and standard SMPs with RRv capacity, the designer must reduce 100% of the WQv calculated in Step 2. If the RRv calculated in this step is greater than or equal to the WQv calculated in Step 2, the designer has met the RRv requirement (and, hence, the water quality volume requirement) and may proceed to Step 5 (Section 2.3.2.5). When compliance cannot be achieved on the first try, designers must return to prior steps to see if an alternative combination of the green infrastructure techniques and standard SMPs with RRv capacity can be applied to achieve compliance with the RRv sizing criteria.
If 100% of the WQv cannot be reduced by applying a combination of the green infrastructure techniques and standard SMPs with RRv capacity, there must be, at a minimum, a reduction of runoff from a percentage of the impervious area constructed as part of the project using the green infrastructure techniques and/or standard SMPs with RRv capacity. The runoff reduction from a percentage of the impervious area is defined as the Specific Reduction Factor (S) and results in a minimum required WQv (referred to in Stormwater Management Design Manual as the “minimum RRv”). The percent reduction is based on the Hydrologic Soil Group(s) (HSG) of the site. The following lists the specific reduction factors for the HSGs:
HSG A = 0.55
HSG B = 0.40
HSG C = 0.30
HSG D = 0.20
The following equation can be used to determine the minimum runoff reduction volume:
RRv (in acre-feet of storage) = [(P)(Rv*)(Ai)] /12
Where:
Ai = (S)(Aic)
Ai = impervious cover targeted for runoff reduction (in acres)
(Aic)= Total area of new impervious cover (in acres)
Rv* = 0.05+0.009(IC) where IC is 100% impervious (i.e., Rv* = 0.95)
S = Hydrologic Soil Group (HSG) Specific Reduction Factor (This is a weighted average of the Specific Reduction Factors for the Hydrologic Soil Groups when there is more than one Hydrologic Soil Group within the project limits.)
The SWPPP must demonstrate that all the green infrastructure planning and design options are evaluated to meet the runoff reduction requirement and provide documentation if any components of this approach are not technically feasible. Projects that cannot meet 100% of runoff reduction requirement must provide a justification that evaluates each of the green infrastructure planning and volume reduction techniques and identify the specific limitations of the site according to which application of this criterion is technically infeasible. Implementation of green infrastructure cannot not be considered infeasible unless physical constraints, hydraulic conditions, soil testing, existing and proposed slopes (detailed contour), or other existing technical limitations are objectively documented. A determination that application of none of the runoff reduction options is feasible may not be based on the cost of implementation measures or lack of space for required footprint of the practice (Note: “Lack of space” is an acceptable justification for not meeting the requirements for redevelopment, but is not acceptable for meeting the requirements for new development). If the minimum Runoff Reduction Volume (RRv) requirement is met using the green infrastructure techniques and/or standard SMPs with RRv capacity, the designer can then proceed to Step 4 (Section 2.3.2.4).
If the minimum Runoff Reduction Volume (RRv) requirement is not met, the technical standard is not met, and NYSDEC will not process the NOI. In this case, the Department must contact the Regional DEC office to discuss the project and options available and site limitations. If the Department and DEC staff come to an agreement on a resolution that is reasonable, but which technically results in the total RRv provided is less than the Minimum RRv required, coverage under the Construction General Permit can be obtained with a 60-business-day review period.
2.3.2.4 Step 4: Apply Standard or Alternative Stormwater Management Practices to Address Remaining Water Quality Volume
In this step, the designer uses standard or alternative practices to meet the remaining water quality volume requirements that cannot be addressed by applying the green infrastructure techniques or the standard SMPs with RRv capacity discussed in the previous section.
The following sections outline the process for using standard and/or alternative practices to meet the WQv requirements not met in Steps 1 through 3.
If the WQv requirements in this section are not met, the technical standard is not met, and NYSDEC will not process the NOI. In this case, the Department must contact the Regional DEC office to discuss the project and options available and site limitations. If the Department and DEC staff come to an agreement on a resolution that is reasonable, but which technically results in a total WQv provided, that is less than the WQv required, coverage under the Construction General Permit can be obtained with a 60-business-day review period.
2.3.2.4.1 Apply Standard Stormwater Management Practices to Address Remaining Water Quality Volume
The Stormwater Management Design Manual provides details for the five groups of standard SMPs to meet water quality treatment goals. The five groups are:
1) ponds
2) stormwater wetlands
3) infiltration practices
4) filtering systems
5) open channel systems
The details in the Stormwater Management Design Manual include descriptors identifying individual features of each SMP. To clarify the details, Attachment A of this appendix provides recommendations on NYSDOT pay item numbers for the descriptors. The designer should select practices from the Stormwater Management Design Manual based on consultations with the Regional Environmental/Landscape Architecture Unit, Regional Maintenance Group, Regional Geotechnical Engineer, Regional Construction Engineer and the Regional Hydraulics Engineer.
The water quality volume to be treated by a standard SMP is determined by using the following equation:
WQv = (P)(Rv)(A) / 12
Where:
WQv = Water Quality Volume (in acre-feet)
P = 90% Rainfall Event Number (see Chapter 4 of the Stormwater Management Design Manual)
Rv = 0.05 + 0.009(IC), the runoff coefficient where IC is the percentage of all impervious areas (not only new impervious areas) within the contributing drainage area (a minimum Rv of 0.2 should be used).
IC = Total impervious area X 100
Practice Contributing Drainage Area (watershed)
A = The total contributing drainage area to the stormwater management practice (in acres)
By using a standard SMP, 100% of the WQv treated by the practice can be applied to meeting the remaining WQv required. A 5 business day review of the NOI would be granted if the entire WQv can be treated using steps 2 through 4.
2.3.2.4.2 Apply Alternative Stormwater Management Practices to Address Remaining Water Quality Volume (from Areas of Redevelopment)
Stormwater Management Practices that are considered “Alternative Practices” are listed on the NYSDEC website at , and are not acceptable for treatment of stormwater runoff from areas of new development, but can be used to meet pretreatment requirements for standard practices, or as primary treatment for areas undergoing redevelopment (i.e., areas where impervious areas are being replaced).
When standard practices are not able to be implemented in areas of redevelopment, the designer may select alternative practices and document the reasons for the use of the alternative practices in the SWPPP. By using an alternative practice, 75% of the WQv treated by the practice can be applied to meeting the remaining WQv required. A 5 business day acceptance of the NOI would be granted if the entire WQv can be treated using steps 2 through 4.
When the designer uses a combination of standard and alternative practices, the Water Quality Volume should be calculated separately for each practice.
The use of alternative practices to address redevelopment requirements in accordance with this guidance would require a 5 business day review for the NOI.
2.3.2.4.3 Apply a Combination of Standard and Alternative Stormwater Management Practices with Impervious Cover Reduction to Address Remaining Water Quality Volume (from Areas of Redevelopment)
The remaining water quality volume requirements can be met by using a combination of impervious cover (IC) reduction of the existing impervious areas and the use of standard and/or alternative practices to treat the runoff from the replaced impervious areas, using the following equation:
% WQv treatment by an alternative practice = (25 - (% IC reduction + % WQv treatment by standard practice + % runoff reduction)) * 3
For example, water quality volume for the alternative practice for the following scenarios can be computed as follows:
5% IC reduction, 20% standard practice, 0% runoff reduction, 0% alternative practice
5% IC reduction, 0% standard practice, 0% runoff reduction, 60% alternative practice
0% IC reduction, 5% standard practice, 5% runoff reduction, 45% alternative practice
5% IC reduction, 5% standard practice, 5% runoff reduction, 30% alternative practice
25% IC reduction, 0% standard practice, 0% runoff reduction, 0% alternative practice
The use of a combination of practices to address redevelopment requirements in accordance with this guidance would require a 5 business day review for the NOI.
2.3.2.5 Step 5: Apply Volume and Peak Rate Control Practices
The SPDES General Permit for Construction Activity requires the extended detention of the volume associated with the one-year, 24-hour storm event (Channel Protection Volume), and post-construction attenuation of the 10-year, 24-hour (Overbank Flood Control) and 100-year, 24-hour (Extreme Flood Control) storm events to the pre-construction site conditions. Designers are required to analyze both the pre- and post-construction site conditions to address the water quantity requirements, when practicable, using downstream analysis, detention, retention, infiltration practices, or green infrastructure strategies. These mitigation measures are not to be confused with stormwater quality practices.
Efforts to perform soil restoration in accordance with the Stormwater Management Design Manual should be considered in the drainage analysis. See Section 2.3.2.1.
2.3.2.5.1 Stream Channel Protection Volume (Cpv)
The Stormwater Management Design Manual requires that the Channel Protection Volume (Cpv) within each drainage area be detained for a 24 hour period (or 12 hour detention if water discharges to a classified trout stream). The 24 hour extended detention period is a period of detention of stormwater intended to reduce the potential for streambank erosion downstream from stormwater discharge points. This methodology is intended to slow the release of stormwater discharges to less than the critical velocity at which channel erosion occurs. The 24 hour period was selected to enable a stormwater management practice to empty or return to a normal water elevation before another storm comes along, while being of long-enough duration to decrease the flow to below the critical velocity. Simply providing peak flow attenuation of the 1-year, 24-hour storm event doesn't necessarily provide release rates below the critical velocity.
When determining the Channel Protection Volume for each drainage outlet, use a Curve Number (CN) and Time of Concentration (Tc) for the drainage area for the post-construction condition. Runoff reduction as a result of the use of green infrastructure practices should be considered; the volume reduction achieved can be deducted from the Cpv.
The Cpv requirement does not apply if either of these conditions apply:
• The entire Cpv is contained within the site using green infrastructure or infiltration systems.
• The site discharges directly to tidal waters or to a fifth order or larger stream (including the Barge Canal System, except feeder canals).
When a practice is designed to detain the Cpv, if the resulting extended detention orifice is less than 3” with a trash rack or 1” if the orifice is protected by a standpipe, then it is acceptable to use a three inch orifice, even though it will not result in retention of the entire Cpv for the required time period. (The Cpv requirement is not waived if the calculated orifice is less than 3”.)
The designer should review the stream conditions within the project, and if the pre- vs. post-construction analysis determines that there is no increase in impervious area or change to runoff characteristics for the 1-year, 24-hour storm event, and there is no evidence of streambank erosion, then detention of the Cpv will not be required. This documentation must be provided in the SWPPP; the NOI will require a 5 business day review.
Streambank stabilization is not considered appropriate mitigative treatment.
For enhanced phosphorus removal, the WQv is equal to the runoff from the 1-year, 24-hour event. Therefore, the only additional requirement necessary to meet the Cpv requirement is to provide 24 hour extended detention of the WQv. In some SMPs (e.g., the Wet Extended Detention Pond), the Cpv requirements are achieved through WQv sizing techniques (i.e., the extended detention orifice is sized to release the Extended Detention Volume (EDv) over 24 hours). In other SMPs (e.g., the Wet Pond) the requirements are not inherent in the design and must be achieved using other means (i.e., provided above the WQv).
2.3.2.5.2 Overbank Flood Control (Qp)
If the project requires coverage under the SPDES General Permit for Construction Activity, the Overbank Flood Control, Qp, (from the 10-year, 24-hour storm event) must be attenuated within each drainage area to the pre-construction discharge rates. The Qp requirement does not apply if either of these conditions apply:
• A downstream analysis reveals that overbank flood control is not needed (see Section 2.3.2.5.4).
• The site discharges directly to tidal waters or to a fifth order or larger stream (including the Barge Canal System, except feeder canals).
If post-construction flow rates do not exceed the pre-construction flow rates, stormwater detention to address overbank flood control is not required (it is important to note the different definitions of pre-development for new development vs. redevelopment when conducting drainage analyses). This information must be documented in the SWPPP.
2.3.2.5.3 Extreme Flood Control (Qf)
If the project requires coverage under the SPDES General Permit for Construction Activity, the Extreme Flood Control, Qf, (from the 100-year, 24-hour storm event) must be attenuated within each drainage area to the pre-construction discharge rates. The Qf requirement does not apply if any of these conditions apply:
• A downstream analysis reveals that extreme flood control is not needed (see Section 2.3.2.5.4).
• The site discharges directly to tidal waters or to a fifth order or larger stream (including the Barge Canal System, except feeder canals).
• Development is prohibited within the ultimate 100-year floodplain.
If post-construction flow rates do not exceed the pre-construction flow rates, stormwater detention to address extreme flood control is not required (it is important to note the different definitions of pre-development for new development vs. redevelopment when conducting drainage analyses). This information must be documented in the SWPPP.
During the 100 year flood event, overtopping of the closed drainage system is expected; therefore, the designer should investigate overland drainage patterns and adjust the expected flow rate accordingly.
2.3.2.5.4 Downstream Analysis
A downstream analysis should be conducted for each discharge point if there is an increase in post construction peak flow rates over the pre construction rates for the 10 (Qp) and 100 (Qf) year flood events. This shall be done by finding the point on the waterbody that has a watershed area ten times greater than the drainage area to the discharge point in question.
The analysis should follow the steps detailed below and referenced in Exhibit 4.
1. Determine the discharge points along the project. A discharge point is defined as the point where a conveyance system (Gutter, ditch, closed drainage system, etc.) discharges water from the project site, typically at a watercourse. In some instances, the discharge may occur at the end of a project, such as where a stream runs parallel to the project.
2. Determine the watershed area of the highway discharge point. This area is then multiplied by 10 to determine the drainage area necessary to accomplish the downstream analysis. As shown in Exhibit 4, the drainage area to the discharge point is 14.24 acres. Therefore the downstream analysis requires a watershed area of 142.4 acres (14.24 x 10).
3. Determine the point of downstream analysis. The process to determine this point is an iterative one. Due to the size of the watersheds, the Regional Hydraulics Engineer may be of assistance in determining the point where the analysis should occur. In Exhibit 4, the drainage area at the analysis point equals 146.92 acres.
If the project outlets directly to a watercourse which has a watershed greater than the required area for analysis, the analysis is conducted just downstream from the confluence (i.e., junction) of the highway drainage outlet. For example, if a highway discharge point has a watershed of 49.42 acres requiring 494.20 acres for analysis, and outlets directly to a stream with a 617.76 acres watershed at the point of confluence, then the analysis point is just below the confluence. No further analysis is required downstream.
If the downstream confluence point (where the drainage area is ten times as great as the project watershed) occurs at a fifth order or greater stream, no analysis of this point is necessary. However, any structures between the project site and the fifth order stream still need to be reviewed. Information used regarding changes of peak flows for the tributary and the stream flow data for the fifth order stream should be provided or summarized in the SWPPP.
4. Compute the pre-construction and post construction peak flows and velocities for the 10 and 100 year design storms just downstream from the confluence (i.e., junction) of the highway drainage outlet and the outlet water course, and at all downstream confluences with first order or higher streams up to and including the downstream analysis point (See Exhibit 4).
5. In addition, an assessment of surface water elevations and hydraulic effects on all downstream structures (bridges, large culverts, houses, etc) should be performed.
6. Upon completion of the analysis, if the post-construction peak flow rates for the 10-year, 24-hour and 100-year, 24-hour events increase the pre-construction flow rates by 5% or less and no downstream structures or buildings are impacted, then there is no attenuation required for the 10 and 100 year storm events.
If the assessment demonstrates that downstream structures (houses, large culverts, bridges, etc.) may be impacted by any increase in peak flow rates, the project must attenuate the 10 and 100 year events regardless of whether or not the 5% increase is met at the downstream analysis point. Impacts to small culverts (driveway pipes, cross culverts, etc), which are typically not designed to pass a 100 year event, should be included in any analysis. These structures should be reviewed for any critical need and engineering judgment should be used in determining whether or not these structures would require attenuation of the 10 or 100 year events.
Exhibit 4 – Downstream Analysis
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2.3.2.6 Technical Deviations and Stormwater Crediting
Treatment of stormwater is a challenge on many highway projects (particularly in urban areas) due to:
• Limited right of way availability.
• The high volumes of offsite water commonly being intercepted by linear highway storm drainage systems.
• Inadequate grades to direct stormwater to an appropriate area for stormwater management.
In some cases, site constraints may be such that it is impractical to achieve the water quality volume requirements for the project within the highway boundaries. In these cases, the Department may use volumes "credited" from the water quality improvements made on offsite areas or other Department projects within the highway corridor, watershed, or geographic region. Activities that may create stormwater credit include practices applied at sites where the Water Quality Volume treated exceeds the required Water Quality Volume or when no permit coverage is required, such as, maintenance activities, projects with under 1 acre of disturbance, and treatment of off-site drainage areas as discussed in Section 2.1.9. A 60 business day review of the NOI would be required for projects using credits from another project/site.
Contact the Water/Ecology Unit of the Environmental Science Bureau for information regarding stormwater crediting.
2.3.2.7 Projects That Do Not Require Stormwater Management Practices
There are some projects that involve earth disturbances greater than 1 acre (0.4 Ha), and accordingly require coverage under the SPDES General Permit for Stormwater Discharges from Construction Activity, but the nature of the disturbance is such that there is minimal threat to water resources, such as maintenance activities that do not meet the definition of “Routine Maintenance Activity”.
See Table 1 in the SPDES General Permit for Construction Activity, Appendix B for a list of activities that would require coverage under the general permit, but the SWPPP would include only an Erosion and Sediment Control Plan.
A SWPPP is required for these types of projects, but shall only contain items 1 – 13, 20, 23 and 25 in Section 2.4. The SWPPP shall contain an Erosion and Sediment Control Plan for the proposed activities, but hydrologic and hydraulic analyses (except those analyses required for development of the Erosion and Sediment Control Plan) or permanent stormwater management practices will not be required.
In addition to the SWPPP, these projects will require inspections by a Qualified Inspector at least every seven days and within 24 hours after storm events 0.5 inches or greater (and documented using Form MURK 6, SPDES Inspection Forms).
For these types of projects in which post construction stormwater practices are not required to be designed or constructed, the SWPPP does not need to be prepared by a Qualified Professional.
These projects will require a 5 business day review.
2.4 STORMWATER POLLUTION PREVENTION PLAN (SWPPP)
The Stormwater Pollution Prevention Plan (SWPPP) shall be a stand alone document, and must be prepared prior to the filing of the Notice of Intent. Many of the elements of the SWPPP will be completed in the course of the design process and designers should create the SWPPP concurrently with the rest of the design documents. The SWPPP will be provided to construction staff at the PS&E submission and shall be made available to the contractor as supplemental information. The NYSDEC may request a copy of the SWPPP for any project. If requested, the SWPPP shall be submitted to the NYSDEC within 5 business days in both paper format and electronic file (pdf only). The SWPPP shall be kept in the construction field office and will be revised as construction necessitates.
The following details the SWPPP components. For projects listed in Table 1 in the SPDES General Permit for Construction Activity, only items 1-13, 20, 23 and 25 are required to be in the SWPPP. For projects listed in Table 2 in the SPDES General Permit for Construction Activity, all of the following items should be in a SWPPP.
A shell for the SWPPP is available in on the Stormwater Webpage on the Department’s IntraDOT at:
(1) Provide background information about the scope of the project, including the location, type and size of project.
• Include text from Chapter 1 of the Design Report. The size should be calculated to the nearest 0.10 acres of all areas disturbed by the contractors operations including, but not limited to, easements, occupancies, releases, and state ROW within the contract limits.
(2) Provide a site map/construction drawing(s) for the project, including a general location map. At a minimum, the site map should show:
• The total project area. – Use the contract drawings, which include all areas disturbed by the contractors operations including, but not limited to, easements, occupancies, releases, and state ROW within the contract limits.
• All improvements. – Use the contract drawings.
• Areas of disturbance. – Use the contract drawings.
• Areas that will not be disturbed. – Use the contract drawings.
• Existing vegetation. – Refer to the contract drawings and include a brief listing of the primary vegetation types, density, and location.
• Onsite and adjacent off-site surface water(s), including vegetated buffers and floodplain boundaries. – Use contract drawings and location map.
• Wetlands and drainage patterns that could be affected by the construction activity. – Use contract drawings and brief description (from Design Report).
• Existing and final slopes (Contours). – Contours should be shown on the Erosion and Sediment Control Plans at an appropriate scale.
• Locations of off-site material, waste, borrow or equipment storage areas. - List any of these areas within the state ROW (including easements, occupancies, and releases).
• Location(s) of the stormwater discharge(s). – Use the contract drawings.
(3) Provide a description of the soil(s) present at the site.
• Provide a list of soil types and their Hydrologic Soil Group (A, B, C, D), and a brief description of how the soil characteristics affect the stormwater management strategies for the project.
• Discuss erosion hazard. See HDM Chapter 9, Section 9.3.7.1.3, On-Site Material, for additional guidance.
• Provide a soil map of the project location
(4) Provide a construction sequencing plan describing the intended sequence of construction activities, including:
a) Clearing and grubbing.
b) Excavation and grading.
c) Utility and infrastructure installation.
d) Any other activity at the site that results in soil disturbance.
• Include and reference the appropriate sections of the Contract Notes and project plans.
• See HDM Chapter 9, Section 9.3.7.1.2, Project Segmenting, for additional guidance
Designers should attempt to limit the amount of disturbed soil at any one time to 5 acres; however, limiting soil disturbances may compromise the use of sound construction techniques and strategies (e.g., balancing cuts and fills). If it is known during design that the project will involve soil disturbances greater than 5 acres, it should be noted in the SWPPP and the NOI.
(5) Provide a description of the pollution prevention measures that will be used to control litter, construction chemicals and construction debris from becoming a pollutant source in the storm water discharges and provide a description of construction and waste materials expected to be stored on-site with updates as appropriate, and a description of controls to reduce pollutants from these materials including storage practices to minimize exposure of the materials to storm water, and spill prevention response.
• Include and reference appropriate sections of Standard Specifications 104-07, 107-08, 107-10, and 107-12.
(6) Describe the temporary and permanent structural and vegetative measures to be used for soil stabilization, runoff control and sediment control for each stage of the project from initial land clearing and grubbing to project close-out, including a description of structural practices to divert flows from exposed soils, store flows, or otherwise limit runoff and the discharge of pollutants from exposed areas of the site to the degree attainable.
• Refer to the details in the E&SC Plans, which show the Erosion and Sediment Control measures that will be utilized on the project. A description of practices is in the SWPPP template.
(7) Identify and show on a site map/construction drawing(s) the specific location(s), size(s), and length(s) of each erosion and sediment control practice.
• Include and reference the E&SC plans.
(8) Provide the dimensions, material specifications, and installation details for all erosion and sediment control practices, including the siting and sizing of any temporary sediment basins.
• Include and reference the appropriate Standard Sheets & contract drawings.
(9) Identify temporary practices that will be converted to permanent control measures.
• Briefly describe the practices in the E&SC Plan that will be installed for temporary controls, then will be used as permanent measures. The locations of these measures should be in the contract drawings.
(10) Provide an implementation schedule for staging temporary erosion and sediment control practices, including the timing of initial placement and the duration that each practice should remain in place.
• Refer to the NYSDOT Standard Specifications Section 107-12 when developing the schedule.
• Include and reference the E&SC plans and staging plans. For complex projects with multiple construction stages, separate E&SC plans may be required for each stage.
• The implementation schedule should be coordinated with the intended sequence of construction activities noted in #4 above.
(11) Provide an inspection/maintenance schedule to ensure continuous and effective operation of the erosion and sediment control practices.
• Include in E&SC plan notes which would reference the appropriate section of the standard specifications (Section 209 of the Standard Specifications).
(12) Provide the name(s) of the receiving water(s).
• Include a list of all of the receiving waters on the project.
(13) Provide a delineation of SWPPP implementation responsibilities for each part of the site.
• Include the statement that the Department is responsible for all areas within the state ROW (including easements, occupancies, and releases).
• During Construction phase, the completed CONR 5, Contractor/Subcontractor SPDES Permit Certification, will indicate the operations for which each contractor will be responsible.
(14) Provide any existing data that describes the stormwater runoff characteristics at the site.
• Use appropriate text from the Design Report (e.g., a history of flooding).
(15) Provide a description for each post-construction stormwater control practice.
• Describe practices that will be implemented and refer to the details.
(16) Identify and show on a site map/construction drawing(s) the specific location(s) and size(s) of each post-construction stormwater control practice.
• Include and reference the appropriate sections of the contract drawings.
(17) Provide a hydrologic and hydraulic analysis for all structural components of the stormwater control system for the applicable design storms.
• Include and reference the appropriate sections of the Drainage Report.
(18) Provide a comparison of the post-development stormwater runoff conditions with the pre-development conditions.
• Include and reference the appropriate sections of the Drainage Report.
• Include a discussion of soil restoration efforts, and how runoff will be affected.
(19) Provide the dimensions, material specifications and installation details for each post-construction stormwater control practice.
• Include and reference the appropriate sections of the contract drawings.
(20) Include documentation regarding impacts to properties listed or eligible for listing on the State of National Register of Historic Places.
a) Information on whether the stormwater discharge or construction activities would have an effect on an applicable property.
b) Results of the screening determinations conducted.
c) A description of the measures necessary to avoid or minimize adverse impacts on applicable property.
d) Any written agreement(s) that the Department has with OPRHP or other governmental agency to mitigate effects.
• Include portions of the Design Report to document that necessary screening has been conducted and provide the documentation in an Appendix to the SWPPP.
(21) Provide a detailed summary of the sizing criteria used to design all post-construction stormwater management practices, including criteria not required by the Design Manual.
(22) Provide an operation and maintenance plan that includes inspection and maintenance schedules to ensure continuous and effective operation of each post-construction stormwater control practice.
• Provide the frequency of the inspections by the Department’s Highway Maintenance personnel, how to determine if maintenance is needed, and the recommended maintenance activity.
• Include NYSDOT Stormwater Management Practices, Operations and Maintenance Manual (Draft June 2014):
(23) Provide justification for any elements of the design that are not in conformance with the technical standards for erosion and sediment control and post-construction stormwater management (including redevelopment). Include the reason for the non-conformance or alternative design and provide information which demonstrates that the alternative in the design is appropriate.
• The SWPPP must clearly identify and document the design difficulties that meet redevelopment application criteria and provide documented justification for the use of proposed alternative approaches.
(24) Demonstrate that all the green infrastructure planning and design options are evaluated to meet the runoff reduction requirement and provide documentation if any components of this approach are not technically feasible.
• Projects that cannot meet 100% of runoff reduction requirement must provide a justification that evaluates each of the green infrastructure planning and reduction techniques and identify the specific limitations of the site according to which application is technically infeasible.
• Include a discussion of areas for which soil restoration is required, and how the requirements are addressed, if applicable.
(25) Provide miscellaneous forms
• Completed Notice of Intent
• NYSDEC Acknowledgement of Notice of Intent
• Activation and Inventory Form (This form is completed by Department Design and Construction staff as a tool to have permanent stormwater management practices constructed as part of the project added to the statewide inventory of stormwater management practices.
As construction commences, additional information will be added to the SWPPP, including, but not limited to, the following:
• CONR 5, Contractor/Subcontractor SPDES Permit Certification (signed by contractor and subcontractors).
• MURK 6, SPDES Inspection Form (including continuation forms)
• CONR 8, SPDES Stormwater Pollution Prevention Plan (SWPPP) Revision Form
• Additional communications with regulatory/resource agencies.
2.5 NOTICE OF INTENT
A Notice of Intent (NOI) is required to be submitted to the NYSDEC prior to any construction activities. The review of the NOI by NYSDEC falls under either one of two scenarios, as determined by the NYSDEC:
• 5 business day (≈7 calendar day) review upon receipt of the NOI. This applies to SWPPPs developed in conformance with NYSDEC’s technical standards in the New York State Standards and Specifications for Erosion and Sediment Control (i.e., The Blue Book) and the New York State Stormwater Management Design Manual.
• 60 business day (≈84 calendar day) review upon receipt of the NOI.
o This applies to SWPPPs not developed in conformance with NYSDEC’s technical standards in the New York State Standards and Specifications for Erosion and Sediment Control (i.e., The Blue Book) and the New York State Stormwater Design Manual. When a 60 business day review is required, the NOI must identify each deviation from the technical standards, why the deviations are needed, and the impact on water quality, if any.
Other considerations:
• The NOI is to be signed by the Regional Director, Regional Design Engineer, Regional Construction Engineer, or Regional Transportation Maintenance Engineer/Regional Director of Operations. The NOI should not be signed by the Regional Environmental Unit Supervisor.
• The SWPPP must be complete prior to the NOI being signed and submitted to DEC.
• The NOI should be submitted prior to PS&E. If this is not possible, the NOI should be submitted with enough time to complete the 5 or 60 business day review prior to the contract award.
NOTICE OF INTENT INSTRUCTIONS
The operator of a stormwater discharge which qualifies for coverage under the SPDES General Permit for Construction Activity must submit a Notice of Intent (NOI) form in order to obtain permit coverage.
The link to the NOI can be found on the NYSDEC website at:
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The NOI on the NYSDEC website is a fillable PDF file. The form cannot be saved on a computer for future use with Adobe® Reader® software, but can be saved using Adobe® Acrobat® Standard software. All information can be typed or hand print legibly. Print capital letters in black ink and avoid contact with the edge of the boxes. Fill in choice circles completely and do not use checkmarks. The SWPPP Preparer and the Owner/Operator must sign the completed NOI. Once submitted and processed, an acknowledgment letter will be returned to the applicant.
Please note: The NOI form cannot be submitted before a Stormwater Pollution Prevention Plan (SWPPP) is prepared.
The completed NOI should be mailed to:
NOTICE OF INTENT
NYSDEC, Bureau of Water Permits
625 Broadway, Albany, NY 12233-3505
Owner/Operator Information
Owner/Operator - New York State Dept. of Transportation
Owner/Operator Contact Person Last Name - The last name of the contact person. This is typically the Regional Landscape Environmental Unit Supervisor, and is very rarely the person designated to sign the NOI. (It is recommended that one person in each region be identified as the contact person for all NOIs as NYSDEC generates the bills for each contact person. The more contact persons listed on the NOIs, the more bills the region will receive.)
Owner/Operator Contact Person First Name - The first name of the contact person.
Owner/Operator Mailing Address - Regional office mailing address for the project.
City – Location of Regional office.
State – NY
Zip – Zip code for the Regional office.
Phone - The phone number of the contact person.
Fax - The fax number of the contact person.
Email - The email address of the contact person.
FED TAX ID – Use 14-6013200.
Project Site Information
Project/Site Name - This should be the project description as shown on the title sheet of the contract drawings. For example: “Reconstruction of Route 5". The PIN should also be included.
Street Address - If the highway where the work is being performed has a local street name, provide this information here. If more than one major street exists on the project, include the street with the largest portion of work. If no street name exists for the facility, the highway route number should be inserted here.
Side of Street – If the project is on the highway, choose “North” as the default answer. If the project involves features adjacent to the highway, indicate what direction from the highway these features are located.
City/Town/Village - Enter the municipality name where the majority of work will be performed.
State - NY
Zip - Enter the zip code of the municipality from the City, Town or Village entered above.
County - Enter the county of the work. If the project encompasses more than one county, enter "Various".
NYSDEC Region - Enter the NYSDEC region that oversees the area of the project.
Name of Nearest Cross Street - The cross street selected should be nearest the midpoint of the project.
Distance to the Nearest Cross Street (Feet) - This distance should be the distance from the midpoint of the project to the cross street. Note that this distance is to be provided in FEET.
Direction to the Nearest Cross Street - This direction should be the direction from the mid point of the project to the cross street.
Tax Map Numbers (Section, Block, Parcel) – This section should be left blank.
Tax Map Numbers - This section should be left blank.
The following items are numbered as shown on the NOI form
1. Provide the Geographic Coordinates for the project site in NYTM units.
The location of the coordinates should be at the midpoint of the project. Use geographic coordinates of the project in NYTM units only. Data must be entered on the form in New York Transverse Mercator (NYTM as easting/northing in NAD 83). Please note NYTM is defined as UTM, Zone 18, meters, extended east & west to cover all of NYS. It is required that applicants look up this information from the Stormwater Interactive Map on NYSDEC's web site. This map provides a tool for locating the coordinates of the site, which automatically returns the data in NYTM format. The data provided in NYTM format must be entered in 6 digits for X (easting) and 7 digits for Y (northing) (example 586130, 4884956). No decimal digits are needed. The Stormwater Interactive Map can be accessed at:
Zoom in to the project location
From the pulldown menu under “Click on Map to:”, select “Get Coordinate”.
2. What is the nature of the construction project? Select the appropriate construction type.
o New Construction is disturbance of a site where no construction or development has previous occurred.
o Redevelopment with increase in imperviousness refers to reconstruction or modification to any existing, previously developed land such as residential, commercial, industrial, institutional or road / highway which involves soil disturbance, and which has additional increase in impervious areas.
o Redevelopment with no increase in imperviousness refers to reconstruction or modification to any existing, previously developed land such as residential, commercial, industrial, institutional or road / highway which involves soil disturbance, and which has NO additional increase in impervious area.
If the project consists of a new road, parking or rest area, or maintenance facility where one had not previously existed, or involves relocating an existing highway on a significantly different horizontal alignment, then the “New Construction” option should be chosen. Otherwise, either of the other two options should be selected.
3. Select the predominant land use for both pre and post development conditions.
Pre Development Existing Land Use - Select only one. The selected land use should represent the land use in the 5 years prior to construction. In most instances, for Department projects, this will be “Road/Highway”.
Post Development Future Land Use - Select only one. In most instances, for Department projects, this will be “Road/Highway”.
4. In accordance with the larger common plan of development or sale, enter the total project site area; the total area to be disturbed; existing impervious area to be disturbed (for redevelopment projects); and the future impervious area constructed within the disturbed area. (Round to the nearest tenth of an acre.)
Total Site Area - The area of the entire project, from the project limits to the proposed highway ROW boundaries. This area should include all temporary easements, temporary occupancies, permanent easements, or fee takings.
Total Area To Be Disturbed - Is the area where vegetation is removed or where soil is exposed due to clearing, grading, or excavation. This should include areas off the highway boundary that typically will be constructed under release, such as driveways & entrance walks. The areas computed should be from the designed slopes, as shown on the contract drawings, and any areas where it is reasonable to assume temporary construction impacts. (While it is possible for construction to alter these project limits, it is impractical for design to account for all of these potential changes.)
Existing Impervious Area To Be Disturbed - Is the impervious areas (pre construction), as measured within the disturbed area as defined above. In no instance should impervious area be included from beyond the project work limits, or Highway boundary, whichever is greater. (This area is to be any existing impervious area disturbed within the project area, regardless of whether the project is considered a “redevelopment project”.)
Future Impervious Area - Is the impervious area (post construction) as measured within the disturbed area as defined above. In no instance should impervious area be included from beyond the project work limits, or Highway boundary, whichever is greater.
5. Do you plan to disturb more than 5 acres of soil at any one time? Select YES or NO.
This answer should be based on the designer’s construction sequencing plan.
6. Indicate the percentage of each Hydrologic Soil Group (HSG) at the site.
Designers should roughly estimate the amount of each soil group within the project limits.
7. Is this a phased project? Select YES or NO.
A phased project is a project that is to be conducted over a long period of time where multiple construction activities may occur on a contiguous area. or where multiple permit coverage may be sought for the same site. The disturbance threshold does not apply only to a "snapshot" of disturbance at a given time but to the long term plan of development where construction may stop and restart under a new permit coverage. Typically, this question should be answered NO.
8. Enter the planned start and end dates of the disturbance activities. The designer should enter the anticipated construction start date (anticipated Award date), and the anticipated construction completion date for the end date. This information must be entered in a 8-digit format (MM/DD/YYYY).
9 Identify the nearest surface waterbody(ies) to which construction site runoff will discharge.
Provide the name(s) of the permanent or intermittent natural, classified surface waterbody(ies) (according to the definition of the Waters of the State or Waters of the United States in the SPDES General Permit) into which the stormwater may be discharged. If this body of water does not have a name, the applicant may enter "unidentified."
9a.Type of waterbody identified in Question 9?
Select applicable choices from the list provided. “On Site” is considered to be a waterbody within the Right-of-Way and the project limits. “Off Site” is considered to be a waterbody outside of the Right-of-Way and the project limits. The location should be defined at the point of discharge.
9b.How was the wetland identified?
Select “Regulatory Map” if the wetland was identified from map showing state or federal wetlands. If the wetland was delineated by Department staff, check “Other“ and enter “NYSDOT staff”.
10. Has the surface waterbody(ies) in question 9 been identified as a 303(d) segment in Appendix E of GP-0-10-001? Select YES or NO., * see note below #11.
11. If this project located in one of the Watersheds identified in Appendix C of GP-0-10-001? Select YES or NO.
A subset of certain 303(d) segments and TMDL watersheds have been selected as waterbodies/watersheds of concern within the stormwater program. These waterbodies/watersheds have been identified for regulation by the SPDES General Permit due to impairment by construction site or urban runoff, which contribute pollutant loads into waterbodies. For transportation projects, discharges to 303(d) segments listed in Appendix E do not trigger additional actions or requirements. (The list of 303(d) segments listed in Appendix E of the SPDES General Permit is not the same as the list of 303(d) segments in Appendix 2 of the SPDES General Permit for MS4s, GP-0-10-002).
The 303(d) segments and TMDL watersheds can be found within the “Water Ecology” folder (under “Stormwater”) on the Department’s Environmental Viewer at:
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12. Is the project located in one of the watershed areas associated with AA and AA-s classified waters? Select YES or NO.
The boundaries of AA and AA-s watersheds can be found on the NYSDEC’s Stormwater Interactive Map at: .
13. Does this construction activity disturb land with no existing impervious cover and where the Soil Slope Phase is identified as an E or F on the USDA Soil Survey? Select YES or NO.
The soil phases are attributes in the USDA Soil Data Viewer GIS software. This is available on the LANDesk Software Deployment Portal, upon request to the IT Coordinator. The soil phases are also included in the County Soil Surveys.
If Yes, what is the acreage to be disturbed?
14. Will the project disturb soils within a State regulated wetland or the protected 100 foot adjacent area? Select YES or NO.
15. Does the site runoff enter a separate stormwater sewer system (including roadside drains, swales, ditches, culverts, etc)? In most cases for Department projects, this should be marked YES. The most immediate discharges from the project should be considered, not the final waterbody to which the stormwater eventually drains.
If the site runoff does not enter a channelized drainage conveyance, this should be marked NO.
16. What is the name of the municipality/entity that owns the separate storm sewer system? In most cases, this will be the New York State Department of Transportation, or if applicable, the local municipality.
17. Does any runoff from the site enter a sewer classified as a Combined Sewer?
A combined sewer is a sewer system where sewage and stormwater are transported in a single system of pipes, usually to a treatment facility. Select YES, NO or UNKNOWN.
The combined sewer overflow areas can also be viewed on the NYSDEC’s Stormwater Interactive Map at: the Department’s Environmental Viewer at:
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Select Water and Ecology/Stormwater/Combined Sewers.
18. Will the future use of this site be an agricultural property as defined by the New York State Agriculture and Markets law? Select NO.
19. Is this property owned by a state authority, state agency, federal government or local government? Select YES.
20. Is this a remediation project being done under a Department approved work plan? (i.e. CERCLA, RCRA, Voluntary Cleanup Agreement, etc.) Select YES or NO.
21. Has the required Erosion and Sediment Control component of the SWPPP been developed in conformance with the current NYS Standards and Specifications for Erosion and Sediment Control (aka Blue Book)'? Select YES or NO.
Typically, the Department’s Standard Specifications for Erosion and Sediment Control, Section 209, and the associated details are consistent with NYSDEC technical standards for erosion and sediment control. The Department, however, does have specifications for erosion or sediment control practices that are not included in the Blue Book. If a practice is proposed for the project that conflicts with the definition, purpose, and design criteria of the practice in the Blue Book, this question should be NO. Minor deviations from the information in the Blue Book, however, especially that information in the Blue Book which is not consistent with the definition, purpose, and design criteria of the practice should not be considered “nonconformance”.
22. Does this construction activity require the development of a SWPPP that includes the post-construction stormwater management practice component (i.e. Runoff Reduction, Water Quality and Quantity Control practices/techniques)? Select YES or NO.
Projects listed in Table 2 in the SPDES General Permit will have Water Quality and Quantity Control Plan components in addition to an Erosion and Sediment Control Plan:
For the project types in Table 1 of the SPDES General Permit this question should be answered "NO" and skip Questions 23 and 27-39.
23. Has the post-construction stormwater management practice component of the SWPPP been developed in conformance with the current NYS Stormwater Management Design Manual'? Select YES or NO.
An electronic copy of this document is available on the NYSDEC website at:
24.The Stormwater Pollution Prevention Plan (SWPPP) was prepared by:
o Professional Engineer (P.E.)
o Soil & Water Conservation District (SWCD)
o Registered Landscape Architect (R.L.A.)
o Certified Professional in Erosion and Sediment Control (CPESC)
o Owner/Operator
o Other (identify in the space provided)
Select one.
The following information should indicate the licensed or certified professional who prepared the SWPPP.
SWPPP Preparer - The Consultant name who prepared the SWPPP. “New York State Dept of Transportation” if prepared by NYSDOT staff.
Contact Name - The name of the licensed or certified professional who prepared the SWPPP. Use format (Last, space, First)
Mailing Address - The business mailing address of the preparer.
City - The municipality where the contact can be reached.
State – The state in the mailing address.
Zip Code - The zip code in the mailing address.
Phone Number - The phone number of the company or individual who prepared the SWPPP.
Fax Number - The fax number of the company or individual who prepared the SWPPP.
Email Address - The email address of the contact person who prepared the SWPPP.
SWPPP Preparer Certification – The SWPPP Preparer should provide his/her name and signature to certify that the SWPPP has been prepared in accordance with the terms and conditions of the SPDES General Permit, and the date that this certification was signed. This certification should be signed by the licensed professional that has prepared the SWPPP, not just consultant staff.
25. Has a construction sequence schedule for the planned management practices been prepared? Select YES or NO. Select YES if the SWPPP includes a construction sequencing schedule.
26. Select all of the erosion and sediment control practices that will be employed on the project site. Check all of the practices that will be utilized on the project.
Post-construction Stormwater Management Practices (SMP) Requirements
27. Identify all site planning practices that were used to prepare the final site plan/layout for the project.
The options provided are the eleven planning practices identified in Section 2.3.2.1. Note that Soil Restoration and Open Space Design are not on the list in the NOI. See question #27a.
27a. Indicate which of the following soil restoration criteria was used to address the requirements in Section 5.1.6 (“Soil Restoration”) of the Design Manual (2010 version).
The options are:
o All disturbed areas will be restored in accordance with the Soil Restoration requirements in Table 5.3 of the Design Manual (see page 5-22). (Note: This only applies to areas that are not intended to be compacted in the post-construction condition.)
o Compacted areas were considered as impervious cover when calculating the WQv Required, and the compacted areas were assigned a post-construction Hydrologic Soil Group (HSG) designation that is one level less permeable than existing conditions for the hydrology analysis. (Note: Areas with compacted HSG D soils should be considered impervious areas when determining Water Quality Volume and performing hydrologic analyses.)
Select the appropriate option.
28. Provide the total Water Quality Volume (WQv) required for this project (based on final site plan/layout). Provide the Water Quality Volume in acre-feet. This is the Initial Water Quality Volume (see Section 2.3.2.2.)
29. Identify the RR techniques (Area Reduction), RR techniques (Volume Reduction) and Standard SMPs with RRv Capacity in Table 1 (See Page 9 of the NOI) that were used to reduce the Total WQv required (#28).
Also, provide in Table 1 the total impervious area that contributes runoff to each technique/practice selected. For the Area Reduction Techniques, provide the total contributing area (includes pervious area) and, if applicable, the total impervious area that contributes runoff to the techniques/practice.
Note: Redevelopment projects shall use Tables 1 and 2 to identify the SMPs used to treat and/or reduce the WQv required. If runoff reduction techniques will not be used to reduce the required WQv, skip to question 33a after identifying the SMPs. Select the practices to be used on the project. The drainage and impervious areas should be aggregated when more than one of a certain practice type (e.g., two infiltration basins) is used. See Section 2.3.2.3 for additional information.
Table 2 is to be completed when Verified Proprietary Practices (including Hydrodynamic Separators, wet vaults and media filters) are used.
30. Indicate the Total RRv provided by the RR techniques (Area/Volume Reduction) and Standard SMPS with RRv Capacity identified in question 29. Provide the Runoff Reduction Volume in acre-feet.
31. Is the Total RRv provided (#30) greater than or equal to the total WQv required (#28). Select YES or NO.
32. Provide the Minimum RRv required based on HSG. Provide the Minimum Runoff Reduction Volume in acre-feet. See Section 2.3.2.3 for additional information.
32a. Is the total RRv provided (#30) greater than or equal to the Minimum RRv Required (#32)? Select YES or NO.
If YES, proceed to question #33. If NO, the sizing criteria has not been met. Contact the Regional (DEC) Office stormwater contact to discuss next steps.
Note: Use the space provided in question #39 to summarize the specific site limitations and justification for not reducing 100% of WQv required (#28). A detailed evaluation of the specific site limitations and justification for not reducing 100% of the WQv required (#28) must also be included in the SWPPP.
IMPORTANT: NYSDEC will not process an NOI if NO is selected for this question. The applicant must contact the Regional DEC office to discuss the project and options available and site limitations. If the applicant and DEC staff comes to an agreement on a resolution that is reasonable, but which technically results in the total RRv provided is less than the Minimum RRv required, the following should occur:
o The agreed-upon solution should be stated in Question #39 with the name of the DEC staff person with whom the applicant was in contact.
o Question #32a should be checked YES.
o The NOI should be submitted for processing. DEC staff will contact the DEC staff noted in Question #39 to confirm that the information provided is true and that the solution is appropriate for the circumstances.
See Section 2.3.2.3 for additional information.
33. Identify the Standard SMPs in Table 1 that were used to treat the remaining total WQv (=Total WQv required in #28 – Total RRv Provided in #30).
Provide in Table 1 the total impervious area that contributes runoff to each practice selected. Use Tables 1 and 2 to identify SMPs used on Redevelopment Projects.
33a.Indicate the Total WQv provided (i.e. WQv treated) by the Standard SMPs identified in question #33 and Standard SMPs with RRv Capacity identified in question #29. Provide the Total Water Quality Volume in acre-feet.
34. Provide the sum of the Total RRv provided (#30) and the WQv provided (#33a). Provide the volume in acre-feet.
35. Is the sum of the RRv provided (#30) and the WQv provided (#33a) greater than or equal to the total WQv required (#28)? Select YES or NO.
If YES, go to question #36. If NO, the sizing criteria has not been met. Contact the Regional (DEC) Office stormwater contact to discuss next steps.
IMPORTANT: NYSDEC will not process an NOI if NO is selected for this question. The applicant must contact the Regional DEC office to discuss the project and options available and site limitations. If the applicant and DEC staff comes to an agreement on a resolution that is reasonable, but which technically results in the sum of the total RRv provided and WQv provided is less than the total WQv required, the following should occur:
o The agreed-upon solution should be stated in Question #39 with the name of the DEC staff person with whom the applicant was in contact.
o Question #35 should be checked YES.
o The NOI should be submitted for processing. DEC staff will contact the DEC staff noted in Question #39 to confirm that the information provided is true and that the solution is appropriate for the circumstances.
36. Provide the Channel Protection Storage Volume (CPv) required and provided or select waiver (#36a), if applicable. Provide the volumes in acre-feet.
There is only one space to enter the volume, so the CPv volumes required and provided at all discharge points should be aggregated.
36a. The need to provide channel protection has been waived because:
o Site discharges directly to tidal waters or a fifth order or larger stream.
o Reduction of the total CPv is achieved on site through runoff reduction techniques or infiltration systems.
If Channel Protection Volume has not been detained, choose one of these waivers. Use the space at question #39 to explain, if necessary.
37. Provide the Overbank Flood (Qp) and Extreme Flood (Qf) control criteria or select waiver (#37a), if applicable.
There is only one space to enter the pre-construction and post-construction volumes for each flood size, so the volumes at all discharge points should be aggregated. Consider the response to question #27a in the drainage analyses.
37a. The need to meet the Qp and Qf criteria has been waived because:
o Site discharges directly to tidal waters or a fifth order or larger stream.
o Downstream analysis reveals that the Qp and Qf controls are not required.
If Qp and Qf have not been attenuated, choose one of these waivers. Use the space at question #39 to explain, if necessary.
38. Has a long-term Operation and Maintenance Plan for the post-construction management practice(s) been developed? Select YES, enter “NYS Dept. of Transportation” in the spaces provided.
The Department has a Stormwater Facilities Operations and Maintenance Manual (September 2003), prepared by Region 8, available on the Department’s website at: .
39. Use this space to summarize the specific site limitations and justification for not reducing 100% of WQv required (#28). (See question 32a) This space can also be used for other pertinent project information.
This space should be used to explain why certain technical standards cannot be met (see #32a and 35).
40. Identify other DEC permits, existing and new, that are required for this project/facility. Check all that apply. Consult with the Regional Landscape Environmental Unit Supervisor to determine additional permits that may be required for the project.
41. Does this project require a US Army Corps of Engineers Wetlands Permit? This should be answered YES for any Corps of Engineers Section 404 or Section 10 permit (not just for projects with wetland impacts).
If YES, indicate size of impact to the nearest tenth of an acre.
42. Is this project subject to the requirements of a regulated, traditional land use control MS4? Select NO, and skip Question #43.
43. Has the “MS4 SWPPP Acceptance” form been signed by the principal executive officer or ranking elected official and submitted along with this NOI? Department SWPPPs do not require acceptance by the local municipality(s). Do not answer this question.
44. If this NOI is being submitted for the purpose of continuing or transferring coverage under a general permit for stormwater runoff from construction activities, please indicate the former SPDES number assigned.
Indicate if this NOI is being submitted for the purpose of continuing coverage by providing the former SPDES number that was assigned. If not, leave this blank.
Owner/Operator Certification
The NOI should be signed by the Regional Director, Regional Design Engineer, Regional Construction Engineer, Regional Transportation Maintenance Engineer or Regional Director of Operations.
2.6 NOTICE OF TERMINATION
Notice of Termination Instructions
A Notice of Termination (NOT) must be submitted to NYSDEC in order to terminate permit coverage. It is important to submit an NOT for a completed project so that NYSDEC will not charge the Department the annual fee for that project.
The NOT can be found on the NYSDEC website at:
The completed NOT should be mailed to:
NYSDEC “Notice of Termination”
Division of Water
625 Broadway, 4th Floor
Albany, NY 12233-3505
Indicate your Permit Identification Number – Fill in the six numbers that follow “NYR”.
Section I - Owner or Operator Information (Items 1-5) Use the same information provided in the NOI form (Page 1).
Section II – Project Site Information (Item 5-8) Use the same information provided in the NOI form (Page 2).
Section III - Reason for Termination (Item 9a-9c) - 9a. All disturbed areas have received final stabilization in accordance with the general permit and SWPPP. If this true, check the box.
Also, enter Date Final Stabilization completed.
9b. Permit coverage has been transferred to another owner/operator. Do not check this box.
9c. Other (Explain on Page 2). If there is a reason why permit coverage has been terminated other than the project has been completed and the site has achieved final stabilization, check this box, and provide an explanation in Section V on Page 2.
Section IV - Final Site Information (Items 10a-11)
10a. Did this construction activity require the development of a SWPPP that includes post-construction stormwater management practices? Select YES or NO. If NO, skip Questions 10b through 10e, and proceed to Question 10f.
10b. Have all post-construction stormwater management practices included in the final SWPPP been constructed? Select YES or NO. If NO, provide an explanation in Section V on Page 2.
10c. Identify the entity responsible for long-term operation and maintenance of practice(s). In most cases this will be the Department. This answer should be consistent with NOI Question 38 and the Maintenance Jurisdiction table in the contract documents. (Permanent Stormwater Management Practices fall into the category of “Highway Drainage”.)
10d. Has the entity responsible for long-term operation and maintenance been given a copy of the operation and maintenance plan required by the general permit? If the responsible entity is the Department, select YES. If another entity has maintenance jurisdiction, provide the maintenance plan and select YES.
10e. Indicate the method used to ensure the long-term operation and maintenance of the post-construction stormwater management practice(s). Select the appropriate box. In most cases, the fourth box (…practices owned by a …government agency…) should be checked.
10f. Provide the total area of impervious surface (i.e. roof, pavement, concrete, gravel, etc.) constructed within the disturbed area. This area should be provided in acres. If the contract was constructed without changes to the contract plans, this should be consistent with NOI Question 4, “Future Impervious Area Within Disturbed”.
Section V – Additional Information/Explanation. Use this section to explain the responses to 9c and 10b, if applicable.
Section VI – MS4 Acceptance – MS4 Official or Duly Authorized Representative - Department projects do not require acceptance by the local municipality(s) or the Department. Do not answer this question.
Section VII – Qualified Inspector Certification – Final Stabilization - Certify your agreement with the statement that appears on the form by signing the NOT form. The person who signs here must provide name, title/position, and date. This certification should be signed by the Qualified Inspector who performed inspections on this project. Section VIII – Qualified Inspector Certification – Post-construction Stormwater Management Practice(s). Certify your agreement with the certification statement that appears on the form by signing the NOT form below the statement. The person who signs here must provide name, title/position, and date. This certification should be signed by the Qualified Inspector who performed inspections on this project.
Section IX – Owner or Operator Certification. Certify your agreement with the certification statement that appears on the form by signing the NOT form below the statement. The person who signs here must provide name, title/position, and date. This certification should be signed by the Engineer in Charge assigned to this project.
2.7 REFERENCES
1. NYSDOT Region 8 Stormwater Facilities Operations and Maintenance Manual (September 2003), NYSDOT, 4 Burnett Boulevard, Poughkeepsie, NY 12603.
2. Guidelines for the Design of Dams, NYSDEC, 625 Broadway, Albany, NY 12233.
3. Highway Design Manual, NYSDOT, 50 Wolf Road, Albany, NY 12232.
4. National Handbook of Conservation Practices, Conservation Practice Standard No. 378, Ponds, Natural Resources Conservation Service, 14th and Independence Avenue, SW, Washington, DC 20250.
5. New York State Standards and Specifications for Erosion and Sediment Control”, NYSDEC, 625 Broadway, Albany, NY 12233, August 2005.
6. New York State Stormwater Management Design Manual, August, 2010
NYSDEC, 625 Broadway, Albany, NY 12233.
7. Standard Specifications, Construction and Materials, NYSDOT, 50 Wolf Road, Albany, NY 12232.
8. State Pollutant Discharge Elimination System (SPDES) General Permit for Stormwater Discharges from Construction Activity, Permit Number GP-0-10-001, January 28, 2010, NYSDEC, 625 Broadway, Albany, NY 12233.
9. Technical Release No. 20, Computer Programs for Project Formulation Hydrology, 1992, USDA, Natural Resources Conservation Service.
10. Technical Release No. 55, Urban Hydrology for Small Watersheds, 1986, USDA, Soil Conservation Service, Washington D.C.
ATTACHMENT A
NYSDEC STORMWATER MANAGEMENT DESIGN MANUAL CHAPTER 6:
DETAIL DESCRIPTORS TRANSLATED INTO NYSDOT ITEM NUMBERS
NYS Stormwater Management Design Manual
Section 6.1 Stormwater Ponds (page 6.4)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC |
| | |Guidelines for Design of Dams states that the upstream slope shall be |
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V |
| | |on 2H). |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|rip-rap pilot channel |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|rip-rap pilot channel (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|Riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None |Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|Plantings |Section 611 – Planting, Transplanting and Post Planting|See Landscape Architecture Group |
| |Care | |
NYS Stormwater Management Design Manual
Section 6.1 Stormwater Ponds (page 6.5)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|hardened pad |Section 620- Bank and Channel Protection |Size appropriately: |
| |founded by Item 207.20 Geotextile Bedding | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
| | | |
| | |Need to specify Strength Class & Apparent Opening Size |
|hardened pad (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|overflow spillway |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|overflow spillway (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|berm |Item 203.01990006 Impervious Embankment In Place | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None |Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|pond drain / reverse pipe |Item 603.XXXX and/or Item 605.XX | |
|Plantings |Section 611 – Planting, Transplanting and Post |See Landscape Architecture Group |
| |Planting Care | |
NYS Stormwater Management Design Manual
Section 6.1 Stormwater Ponds (page 6.6)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|overflow spillway |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|overflow spillway (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|berm |Item 203.01990006 Impervious Embankment In Place | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC |
| | |Guidelines for Design of Dams states that the upstream slope shall be |
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V |
| | |on 2H). |
|riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None |Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|pond drain / reverse pipe |Item 603.XXXX and/or Item 605.XX | |
NYS Stormwater Management Design Manual
Section 6.1 Stormwater Ponds (page 6.7)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|overflow spillway |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|overflow spillway (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|Riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None | Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|pond drain / reverse pipe |Item 603.XXXX and/or Item 605.XX | |
NYS Stormwater Management Design Manual
Section 6.1 Stormwater Ponds (page 6.8)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|weir wall outlet structure |Section 555- Structural Concrete | |
|weir wall outlet structure |Item 632.40000008 Precast Concrete Retaining Wall |The finish of all exposed wall surfaces shall be as shown on the |
|(alternate) | |plans. |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|submerged earth berm |Item 203.01990006 Impervious Embankment In Place | |
|hooded low flow orifice |None |Special Note - Cost to be included in price bid for Weir Wall Outlet |
| | |structure. Detail design. |
NYS Stormwater Management Design Manual
Section 6.2 Stormwater Wetlands (page 6.23)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|weir wall |Item 620.11 PVC Coated Galvanized Gabions | |
|weir wall (alternate) |Item 555.0105 Concrete for Structures, Class A | |
|weir wall (alternate) |Item 632.40000008 Precast Concrete Retaining Wall |The finish of all exposed wall surfaces shall be as shown on the |
| | |plans. |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|gabion wall |Item 620.11 PVC Coated Galvanized Gabions | |
|riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None | Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|pond drain / reverse pipe |Item 603.XXXX and/or Item 605.XX | |
|wetland topsoil |Item 610.1406 Topsoil – On-Site Wetland Materials | |
| |Item 610.1407 Topsoil – Wetland Materials | |
NYS Stormwater Management Design Manual
Section 6.2 Stormwater Wetlands (page 6.24)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None |Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|pond drain / reverse pipe |Item 603.XXXX and/or Item 605.XX | |
|Wetland Topsoil |Item 610.1406 Topsoil – On-Site Wetland Materials | |
| |Item 610.1407 Topsoil – Wetland Materials | |
NYS Stormwater Management Design Manual
Section 6.2 Stormwater Wetlands (page 6.25)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|concrete spillway |Item 555.0105 Concrete for Structures, Class A | |
|concrete spillway (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None |Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|pond drain / reverse pipe |Item 603.XXXX and/or Item 605.XX | |
|wetland topsoil |Item 610.1406 Topsoil – On-Site Wetland Materials | |
| |Item 610.1407 Topsoil – Wetland Materials | |
NYS Stormwater Management Design Manual
Section 6.2 Stormwater Wetlands (page 6.26)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|swale |Item 610.1401 Topsoil – Reuse On-Site Materials | |
| |Item 610.1402 Topsoil - Roadside | |
| | | |
| |Item 610.1601 Establishing Turf - Roadside | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|anti-seep collar or filter |None |Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
|pond drain |Item 603.XXXX and/or Item 605.XX | |
|half round trash rack |None |Special Note - Cost to be included in price for riser item |
|wetland topsoil |Item 610.1406 Topsoil – On-Site Wetland Materials | |
| |Item 610.1407 Topsoil – Wetland Materials | |
NYS Stormwater Management Design Manual
Section 6.3 Stormwater Infiltration (page 6.32)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|plunge pool |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | |Item 620.04 Stone filling (Medium) |
|plunge pool (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|concrete level spreader |Item 555.0105 Concrete for Structures, Class A | |
|concrete level spreader (alternate)|Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|grass channel |Item 610.1401 Topsoil – Reuse On-Site Materials | |
| |Item 610.1402 Topsoil - Roadside | |
| | | |
| |Item 610.1601 Establishing Turf - Roadside | |
|observation well with screw top lid|Meeting the requirements of §706-18 Perforated PVC |Nominal Size 150 mm. Screw top (lockable) lid. |
| |Underdrain Pipe. | |
|pea gravel filter layer |Section 623- Screened Gravel, Crushed Gravel, Crushed |Refers to §703-02 for gradation. Specify Size Designation "1" from |
| |Stone, Crushed Slag |Table 703-4 Sizes of Stone, Gravel and Slag |
|filter fabric |Item 207.22 Geotextile Drainage |Strength Class & Apparent Opening Size Class |
|1.5 in. to 2.5 in. diameter clean |Section 623- Screened Gravel, Crushed Gravel, Crushed |Refers to §703-02 for gradation. Specify Size Designation 4A from |
|stone |Stone, Crushed Slag |Table 703-4 Sizes of Stone, Gravel and Slag |
|sand filter (or fabric equivalent) |Meeting the requirements of §703-07 Concrete Sand. | |
|sand filter (or fabric equivalent) |Item 207.22 Geotextile Drainage |Strength Class 2 & Apparent Opening Size Class B |
|(alternative) | | |
|runoff exfiltrates through | |Subsurface explorations may be required to define the permeability of|
|undisturbed subsoils with a minimum| |the subsoils. A geotechnical engineer may perform tests on the jar |
|rate of 0.5 in. per hour | |samples; perform a drill hole permeability test or percolation test. |
NYS Stormwater Management Design Manual
Section 6.3 Stormwater Infiltration (page 6.33)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|stilling basin |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|stilling basin (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|concrete level spreader |Item 555.0105 Concrete for Structures, Class A | |
|concrete level spreader (alternate)|Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|grass channel |Item 610.1401 Topsoil – Reuse On-Site Materials | |
| |Item 610.1402 Topsoil - Roadside | |
| | | |
| |Item 610.1601 Establishing Turf - Roadside | |
|flat basin floor with grass floor |Item 610.1401 Topsoil – Reuse On-Site Materials | |
| |Item 610.1402 Topsoil - Roadside | |
| | | |
| |Item 610.1601 Establishing Turf - Roadside | |
|back-up underdrain pipe |Section 605- Underdrains. | |
| | | |
| |Item 605.17xx Optional Underdrain Pipe. | |
|embankment |Item 203.01990006 Impervious Embankment In Place |Vertical Scale Exaggerated. NRCS Pond No. 378 states that neither |
| | |upstream nor downstream slopes shall be steeper than 1V on 2H. NYSDEC|
| | |Guidelines for Design of Dams states that the upstream slope shall be|
| | |no steeper than 1V on 3H and the downstream slope (without seepage |
| | |control) shall be no steeper than 1V on 3H (with seepage control - 1V|
| | |on 2H). |
|stable outfall |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|stable outfall (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|riser |Item 604.50XXYY- Special Drainage Structure | |
|barrel (for riser) |Item 603.XXXX - Standard Pipe Item | |
|clean-outs |None |Special Note - Cost to be included in price of underdrain pipe item. |
|valve |None |Special Note - Cost to be included in price of underdrain pipe item. |
|anti-seep collar or filter |None |Special Note - Cost to be included in price of barrel item. |
|diaphragm | | |
NYS Stormwater Management Design Manual
Section 6.4 Stormwater Filtering Systems (page 6.45)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|filter bed | Item 605.0901 Underdrain Filter, Type I. | |
|top soil | Item 610.1401 Topsoil – Reuse On-Site Materials |Meeting the requirements of §713-01 Topsoil |
| |Item 610.1402 Topsoil - Roadside | |
| | | |
|clean washed concrete sand |Item 203.28000009 Filter Sand for Sand Filters |Meeting the requirements of §703-07 Concrete Sand |
|filter fabric |Item 207.22 Geotextile Drainage |Strength Class 2 & Apparent Opening Size Class B |
|perforated pipe/ gravel underdrain |Section 605- Underdrains. | |
|system |Item 605.17xx Optional Underdrain Pipe. | |
| |Item 605.0901 Underdrain Filter, Type I. | |
|perforated standpipe detention |Item 605.XX | |
|structure | | |
|flow diversion structure |Item 604.50XXYY - Special Drainage Structure | |
NYS Stormwater Management Design Manual
Section 6.4 Stormwater Filtering Systems (page 6.46)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|debris screen |Section 623- Screened Gravel, Crushed Gravel, Crushed |Refers to §703-02 for gradation. Specify Size Designation 1A from |
| |Stone, Crushed Slag |Table 703-4 Sizes of Stone, Gravel and Slag |
|sand |Item 203.28000009 Filter Sand for Sand Filters | Meeting the requirements of §703-07 Concrete Sand |
|gravel |Section 605- Underdrains. | |
| |Item 605.0901 Underdrain Filter, Type I. | |
|clean washed sand |Item 203.28000009 Filter Sand for Sand Filters |Meeting the requirements of §703-07 Concrete Sand |
|perforated pipe in a gravel jacket |Section 605- Underdrains. | |
| |Item 605.1702 Optional Underdrain Pipe. | |
| |Item 605.0901 Underdrain Filter, Type I. | |
|access grates |Item 655.XX - Frames and Grates | |
|manhole |Item 655.XX - Frames and Grates | |
|outlet pipe |Item 603.XXXX - Standard Pipe Item | |
|cleanouts |None |Special Note - Cost to be included in underdrain pipe item |
|Concrete Structure |Item 604.50170008, Underground Stormwater Detention |Metric only – no US Customary equivalent. |
| |System | |
NYS Stormwater Management Design Manual
Section 6.4 Stormwater Filtering Systems (page 6.47)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|clean washed sand |Item 203.28000009 Filter Sand for Sand Filters | Meeting the requirements of §703-07 Concrete Sand |
|filter fabric |Item 207.22 Geotextile Drainage |Strength Class 2 & Apparent Opening Size Class B |
|perforated pipe in a gravel jacket |Section 605- Underdrains. | |
| |Item 605.1701 Optional Underdrain Pipe. | |
| |Item 605.0901 Underdrain Filter, Type I. | |
|outlet pipe |Item 605.1701 Optional Underdrain Pipe | |
|inlet/ access grates |Item 655.XX - Frames and Grates | |
|curb stops |Item 609.40000015 - Reinforced Precast Concrete | |
| |Parking Block | |
|Concrete Structure |Item 604.50170008, Underground Stormwater Detention |Metric only – no US Customary equivalent. |
| |System | |
NYS Stormwater Management Design Manual
Section 6.4 Stormwater Filtering Systems (page 6.48)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|flow diversion structure |Item 555.0105 Concrete for Structures, Class A | |
|flow diversion structure |Item 632.40000008 Precast Concrete Retaining Wall |The finish of all exposed wall surfaces shall be as shown on the |
|(alternate) | |plans. |
|flow diversion structure |Item 620.50000017 Cabled Concrete Erosion Control | |
|(alternate) |Revetment System | |
|50/50 peat/sand mixture |Item 203.28000009 Filter Sand for Sand Filters610.10 |Use Compost Type B or C |
| |Compost |Due to the coefficient of permeability, the filter using peat/sand |
| | |mixture will require a larger footprint than a filter using leaf |
| | |compost. |
|sand |Item 203.28000009 Filter Sand for Sand Filters | Meeting the requirements of §703-07 Concrete Sand. |
|geotextile all sides (top & bottom)|Item 207.22 Geotextile Drainage |Do not wrap all sides. Only install geotextile on top of gravel |
| | |underdrain system. |
| | |Strength Class 2 & Apparent Opening Size Class B. |
|gravel underdrain system |Section 605- Underdrains. | |
| |Item 605.1702 Optional Underdrain Pipe. | |
| |Item 605.0901 Underdrain Filter, Type I. | |
|leaf compost |Item 610.10 Compost, | Type D Leaf Compost |
|perforated standpipe |Item 605.XX | |
NYS Stormwater Management Design Manual
Section 6.4 Stormwater Filtering Systems (page 6.49)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|stone diaphragm | |Stone diaphragm is not a part of the bioretention structure |
|grass filter strip |Item 610.1401 Topsoil – Reuse On-Site Materials | |
| |Item 610.1402 Topsoil - Roadside | |
| |Item 610.1601 Establishing Turf - Roadside | |
|sand layer |Item 203.28000009 Filter Sand for Sand Filters | Sand can be used in lieu of filter fabric. |
| | |Meeting the requirements of §703-07 Concrete Sand. |
|berm |Item 203.03 Embankment In Place | |
|mulch |Item 610.110x Mulch for Planting | See specification for appropriate mix. |
|planting soil |Item 208.01030022 Bioretention and Dry Swale Soil | Also use Item 208.01040022 Laboratory Testing for Soil |
| | |Phosphorus Concentration |
|filter fabric |Item 207.22Geotextile Drainage |Strength Class 2 & Apparent Opening Size Class B |
|gravel jacket |Section 605- Underdrains. | |
| |Item 605.0901 Underdrain Filter, Type I. | |
|perforated pipe |Section 605- Underdrains. | |
| |Item 605.1702 Optional Underdrain Pipe. | |
|curb stops |Item 609.40000015 - Reinforced Precast Concrete Parking | |
| |Block | |
NYS Stormwater Management Design Manual
Section 6.5 Open Channel Systems (page 6.60)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|riprap |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | | |
| | |Item 620.04 Stone filling (Medium) |
|rip-rap (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|optional check dam |Item 209.1106 - Check Dam, Stone-Permanent | |
|gravel inlet trench |Section 623- Screened Gravel, Crushed Gravel, Crushed |Refers to §703-02 for gradation, unless otherwise specified. To open |
| |Stone, Crushed Slag |up the gradation, Specify Size Designation CA2 from Table 501-2 |
| | |Coarse Aggregate Gradations. |
|permeable soil |Item 208.01030022 Bioretention and Dry Swale Soil | Also use Item 208.01040022 Laboratory Testing for Soil Phosphorus |
| | |Concentration |
|filter fabric |Item 207.22 Geotextile Drainage |Strength Class 2 & Apparent Opening Size Class B |
|gravel |Item 605.0901 Underdrain Filter, Type I | |
|underdrain perforated pipe |Section 605- Underdrains. | |
| | | |
| |Item 605.1701 Optional Underdrain Pipe. | |
|pea gravel diaphragm | |Stone diaphragm is not a part of the dry swale |
|1/2 round pipe weir |None |Special Note - Cost to be included in price bid for culvert item |
|culvert |Item 603.XXXX - Standard Pipe Item | |
NYS Stormwater Management Design Manual
Section 6.5 Open Channel Systems (page 6.61)
[pic]
|NYSDEC |NYSDOT |Comments |
|Detail Reference |Item Number and Specification | |
| |(US Customary) | |
|riprap |Section 620- Bank and Channel Protection |Size appropriately: |
| | | |
| | |Item 620.03 Stone Filling (Light) |
| | |Item 620.04 Stone filling (Medium) |
|rip-rap (alternate) |Item 620.50000017 Cabled Concrete Erosion Control | |
| |Revetment System | |
|optional check dams |Item 209.1106 - Check Dam, Stone-Permanent | |
|pea gravel diaphragm | |Stone diaphragm is not a part of the wet swale |
-----------------------
Pavement Work That Does Not Expose Soil or Disturb the Bottom 150 mm (6”) of Subbase
2A - Example Impervious and Disturbed Areas for a Highway Widening Segment
Proposed Highway Boundary
Relocated Driveway
Existing Pvmt.
Proposed Pvmt.
Relocated Bridge
2B - Example Impervious and Disturbed Areas for a Bridge Replacement Segment
Existing Alignment
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