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Nonpoint Source Guidance and Technical Assistance

Best Management Practice (BMP) is a term used to describe pollution control systems that treat, slow, divert, or capture nonpoint source pollutants. BMPs are the actions on the ground that help to improve and restore water quality. Identifying the appropriate BMPs is critical to a successful watershed plan or implementation plan. The BMPs that are selected depends on the type of nonpoint source pollution of concern, the land use and the management goal (for example, meeting a reduction goal).

Listed below are the BMP catalogues approved by the Nonpoint Source Program and consistent with Clean Water Act Section 319. Each BMP document describes practices, life spans, cost, effectiveness, pollutants captured, and operation and maintenance. These references may help to guide selection of BMPs to be included in watershed plans, implementation plans, project proposals or funding applications to restore or protect waters.

Catalogue Title Description
Agricultural Best Management
Practice Systems Catalogue (PDF)
(499 KB)
Agricultural conservation management systems and component practices,
including management system lifespans

Beach Restoration Practices to Reduce Bacteria and Nutrient Loading (PDF)(197 KB)

Management practices that reduce the volume of contaminated stormwater runoff that drains into nearshore waters or reduce the presence of nuisance wildlife are eligible for Water Quality Improvement Project (WQIP) funding.
Construction Management
Practices Catalogue (PDF)
(4.4 MB)
Management practices for controlling nonpoint source pollution from
construction sites
Hydrologic and Habitat Modification
Management Practices Catalogue (PDF)
(2.7 MB)
Practices for nonpoint pollution from eroding stream banks, scouring or filling flood control
channels, excessively high or low flows from reservoir releases, or insufficiently
circulating water impoundments
Priority In-Waterbody Best Management Practices to reduce phosphorus loading (PDF, 165 KB) For waterbodies experiencing excessive algae and plant growth, low water clarity, and other impairments due to internal cycling of nutrients (primarily phosphorus), practices to reduce internal cycling of nutrients that are eligible for Water Quality Improvement Project (WQIP) funding.
Leaks, Spills and Accidents
Management Practice Catalogue (PDF)
(1.8 MB)
Practices for chemical and petroleum bulk storage facilities and transportation
Marina Operations for Existing
Facilities (PDF)
(1.5 MB)
Methods of handling water runoff and ways to prevent substances
commonly found at marinas from contaminating waterways
NYS Natural Resource Conservation
Service Technical Guide-Conservation Practices

(link leaves DEC website; select NYS, then your county, go to Section IV)
Technical information about the conservation of soil, water, air, and related plant and animal resources
NYS Standards and Specifications for Erosion
and Sediment Controls (bluebook)

Standards and specification for soil and sediment controls for construction activities
Onsite Wastewater Treatment
Systems Management Practices
Catalogue (PDF)
(4.2 MB)
Management practices for failing onsite septic systems
Roadway and Right-Of-Way
Maintenance Management Practices
Catalogue (PDF)
(1.6 MB)
Practices for transportation and utilities right-of-way management
Silviculture Management Practices
Catalogue (PDF)
(1.6 MB)
Forest resource management practices
Stream Corridor Management:
A Basic Reference Manual (PDF)
(3.1 MB)
Techniques for assessing land use impacts on streams and steps to
implement best management practices for stream protection
Stormwater Management Design Manual Stormwater management practices, including: size, design, selection and location to comply with State stormwater performance standards

The New York Nonpoint Source Program also has approved additional BMPs, control measures and guidance; these are identified with links, in Appendix A of the 2014 New York State Nonpoint Source Management Program (PDF, 367 KB).

BMP Efficiency

BMPs may be selected because of the resource area (lake, river, wetland), land use (agriculture, urban), to address a specific pollutant or to achieve a management goal (e.g., meet a pollutant reduction goal). A lot of research has been done to determine how efficient a BMP is at treating or capturing pollutants from impacting or reaching waterbodies.These efficiencies may be achieved if the BMPs have been appropriately sized, constructed and maintained.

Excess nutrients and sediments can harm waterbodies. The water quality goal for many watershed plans or projects is to identify BMPs that will reduce the amount of these pollutants in the watershed. When developing a watershed plan, it is important to understand what the current pollutant loads are and what practices will achieve the reductions needed to restore water quality. To ensure consistency when estimating potential load reductions for selected BMPs, DEC has developed the table below with accepted efficiencies for nitrogen, phosphorus and sediment for commonly implemented practices. Please note that efficiencies are provided as an average; efficiencies may vary depending on the soils, slope, geology or rainfall within the area where the practice is installed.

For more information about the agriculture management practice efficiencies go to the Chesapeake Bay Assessment Scenario Tool (link leaves DEC website) and for the urban management practice efficiencies go to the New York State Stormwater Design Manual (NYSSDM).

Accepted Best Management Practice Efficiencies
Management Practice Land Use Average Nitrogen Efficiency (%) Average Phosphorus Efficiency (%) Average Sediment Efficiency (%)
Barnyard runoff control (roofs and covers) Agriculture 20% 20% 40%
Bioretention/raingarden with underdrain Urban 40% 40% 80%
Bioretention/raingarden without underdrain Urban 100% 100% 100%
Bioswale with underdrain Urban 40% 40% 80%
Bioswale without underdrain Urban 100% 100% 100%
Cover crop Agriculture 25% 11% 15%
Dirt and gravel road erosion and sediment control Agriculture --- --- 2.77 lbs/ft
Ditch/channel stabilization Urban 40% 40% 80%
Dry ponds Urban 40% 40% 80%
Infiltration trench Urban 100% 100% 100%
Permeable pavement with underdrain Urban 40% 40% 80%
Permeable pavement without underdrain Urban 100% 100% 100%
Prescribed grazing/rotational grazing Agriculture 10% 24% 30%
Riparian buffer/filter strip Urban 40% 40% 80%
Riparian forest buffer Agriculture 42% 38% 50%
Riparian grass buffer Agriculture 30% 38% 50%
Rooftop runoff disconnection Urban 40% 40% 80%
Septic connection --- 100% 100% ---
Septic pumping --- 5% 5% ---
Stream fencing Agriculture 30% 38% 50%
Wet ponds and wetlands Urban 40% 40% 80%
Wetland restoration Agriculture 16% 31% 10%

Pollutant Load Reduction Calculator

There are many methods or models that may be used to estimate nonpoint source pollutant load reductions. The EPA Region 5 Spreadsheet Tool for Estimating Pollutant Load (STEPL) (link leaves DEC website) model may be used.

DEC has developed a simple spreadsheet calculator for applicants of the Water Quality Improvement Project (WQIP) funding program. Applicants can download the Pollutant Load Reduction Calculator Instructions (PDF, 328 KB) and corresponding Pollutant Load Reduction Calculator Spreadsheet (Excel, 23 KB) that can be used to compare estimated pollutant load reductions for different project types or locations and assist with developing an application for funding.

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