Low Impact DevelopmentBest Management Practices

NJDEP Nonstructural Stormwater Management

Rules for All Sites • Protect areas that provide water quality benefits or areas

susceptible to erosion and sediment loss• Minimize impervious surfaces and break up or disconnect the flow

of runoff over impervious surfaces• Maximize the protection of natural drainage features and vegetation• Minimize the decrease in the pre-construction “time of

concentration”• Minimize land disturbance including clearing and grading• Minimize soil compaction• Provide low maintenance landscaping that encourages retention

and planting of native vegetation and minimizes the use of lawns, fertilizers, and pesticides

• Provide vegetated open-channel conveyance systems discharge into and through stable vegetated areas

• Provide preventative source controls

Nonstructural LID BMP Categories

• Vegetation and Landscaping

• Minimizing Site Disturbance

• Impervious Area Management

• Time of Concentration Modifications

Vegetation and Landscaping

• Pervious vegetated areas reduce runoff volumes and peaks through infiltration, surface storage, and evapotranspiration

• Provide a pervious surface for groundwater recharge, particularly during dormant or non-growing seasons

Vegetation and Landscaping

• Preservation of Natural Areas– Especially important in areas with high groundwater

or aquifer recharge capabilities

• Native Ground Cover– Areas covered with turf grass generate more runoff

that other types of vegetation– Native plants are low maintenance with lower fertilizer

and water needs

• Vegetative Filters and Buffers– Dense vegetative cover and low surface slopes

provide cost effective filters

Minimizing Land Disturbance

• Can be used during all phases of land development

• Helps to reduce post-development site runoff volumes and pollutant loads

• Maintains existing groundwater recharge rates

Minimizing Land Disturbance

• Begins during planning and design phase• Goal is to limit clearing, grading, and

disturbances• Sites should be selected so that:

– Roadway and building patterns match existing land forms

– Development is concentrated on areas with lowest soil permeability

– Soil compaction should be minimized and areas that are compacted should be scarified 12 inches

Impervious Area Management

• Impervious surfaces directly linked to degradation of surface waters

• Increased impervious surfaces increase runoff volumes and velocities leading to erosion, flooding, and higher rates of pollution

• Reducing impervious surfaces are an economical way to meet NJDEP regulations

Impervious Area Management

• Streets and Sidewalks– Streets should be of narrowest possible width

consistent with safety and traffic concerns– Porous pavement should be used for

sidewalks and low traffic streets

• Parking Areas– Porous pavers and vegetative islands should

be used– Parking decks can lower the overall footprint

Impervious Area Management

• Vegetated Roofs– Consists of lightweight vegetated planting bed

installed on a new or existing roof– Highly effective and used throughout Europe– Relatively low cost and require little

maintenance – Turn an otherwise unsightly area into a

beautiful garden

Time of Concentration Modifications

• Time of concentration (TC): the time needed to drain runoff from an area

• The shorter the TC, the greater the peak runoff rates

• While difficult to control, especially in the Pinelands, a combination of the methods previously will help to lengthen the TC

Richard Stockton College has the choice to meet the minimum requirements set by the DEP or be the vanguard for Low Impact Development in New Jersey.

By leading the way in LID, Stockton will become an even more

aesthetically beautiful campus, lower maintenance costs, and be

the center of much positive publicity.