By Tucker Simmons and Dr. Clay Emerson, PE, CFM
People generally think of green infrastructure as an eco-friendly way to handle stormwater runoff. While many green infrastructure elements are planned and managed specifically for stormwater control, the capabilities and benefits are far reaching. In this piece, we’ll provide an in-depth look at all that green infrastructure encompasses, best practices, and real-world examples of green infrastructure projects in action.
WHAT IS GREEN INFRASTRUCTURE?
Defined as an approach to water management that protects, restores, or mimics the natural water cycle, green infrastructure can be implemented for large scale projects and small scale projects alike.
Unlike conventional, or “gray” infrastructure, green infrastructure uses vegetation, soil, and other natural components to manage stormwater and generate healthier urban environments. Green infrastructure systems mimic natural hydrology to take advantage of interception, evapotranspiration and infiltration of stormwater runoff at its source. Examples include permeable pavers, rain gardens, bioretention basins, rain barrels, and tree boxes.
WHY IS GREEN INFRASTRUCTURE BENEFICIAL?
Green infrastructure provides various benefits, including cleaning and conserving water, reducing flooding, improving public health, providing jobs, beautifying neighborhoods, supporting wildlife and providing economic benefits at both the larger community and individual household level. Let’s take a closer look at some of the primary benefits:
Prevents Flooding: By absorbing and slowing the flow of water, green infrastructure can reduce the burden on storm sewer systems and mitigate localized flooding.
Saves Money: While some green infrastructure designs may require the same or greater initial investment than conventional strategies, green design methods provide a big return in reducing costs over the long-term.
Improves Water Quality: Through natural absorption and filtration processes, green infrastructure significantly reduces stormwater runoff volume, decreases the pollutants and particulates within the stormwater, and improves the quality of the runoff flowing into surrounding water bodies.
Improves Air Quality: Green infrastructure techniques like tree boxes, green roofs and vegetative barriers have long been associated with improving air quality. Urban tree boxes help shade surfaces, effectively putting moisture into the air while reducing greenhouse gases. Trees mitigate heat and air pollution, both cooling and cleaning the air.
Enhances Aesthetics: Many green infrastructure practices utilize native plants and trees to improve runoff absorption and reduce stormwater pollution. This vegetation can provide a sound barrier or privacy screen for properties, and enhances the overall aesthetics of the surrounding environment.
Increases Property Values: Research shows that property values increase when trees and other vegetation are present in urban areas. Planting trees can increase property values by as much as 15%.
LARGE-SCALE GREEN INFRASTRUCTURE IMPLEMENTATION:
With the use of proper design techniques, green infrastructure can be applied almost anywhere and is especially beneficial in urban areas. In developed environments, unmanaged stormwater creates two major issues: one related to the volume and timing of stormwater runoff (flooding) and the other related to pollutants the water carries. Green Infrastructure in urban environments can recharge groundwater, decrease runoff, improve water quality, and restore aquatic habitats while controlling flooding.
Across the United States, more than 700 cities utilize combined sewer systems (CSS) to collect and convey both sanitary sewage and stormwater to wastewater treatment facilities. During dry weather, all wastewater flows are conveyed to a sewage treatment plant where it receives appropriate treatment before it is discharged to the waterway. However, during heavy rainfall or significant snowmelt, the additional flow exceeds the capacity of the system resulting in a discharge of untreated sewage and stormwater to the waterway; this discharge is referred to as a combined sewer overflow (CSOs). For many cities with CSS, CSOs remain one of the greatest challenges to meeting water quality standards. Green infrastructure practices mimic natural hydrologic processes to reduce the quantity and/or rate of stormwater flows into the CSS.
New Jersey, as part of the 2012 USEPA’s Integrated Municipal Stormwater and Wastewater Planning Approach Framework, utilized green infrastructure as one of the main components in managing its CSS and reducing CSOs. Because of the flexibility of green infrastructure in design performance, it can reduce and mitigate localized flooding and sewer back-ups while also reducing CSOs. An integrated plan that addresses both overflows and flooding can often be more cost-effective than addressing these issues separately. New Jersey, in addition to meeting its CSO reduction goals, is using green infrastructure throughout the sewershed to build resilience to large storm events and improve stormwater management.
Stormwater planters installed by the Philadelphia Water Department
Philadelphia takes advantage of numerous green stormwater infrastructure programs such as Green Streets, Green Schools, and Green Parking. There are a wide variety of green infrastructure practices that Philadelphia is using to decrease stormwater runoff throughout the entire city. After just five years of implementing the Green City, Green Waterplan, Philadelphia has reduced the stormwater pollution entering its waterways by 85%. Using over 1,100 green stormwater tools (i.e. CSO, living landscapes, permeable surfaces, etc.), in just one year, Philadelphia was able to prevent over 1.7 billion gallons of polluted water from entering their rivers and streams.
New York City is using a green infrastructure program, led by its Department of Environmental Protection, that utilizes multiple green infrastructure practices to promote the natural movement of water while preventing polluted stormwater runoff from entering sewer systems and surrounding waterbodies. While attaining this goal, the green infrastructure also provides improvements in water and air quality, as well as improves the aesthetics of the streets and neighborhoods. According to the NYC Green Infrastructure Plan, “By 2030, we estimate that New Yorkers will receive between $139 million and $418 million in additional benefits such as reduced energy bills, increased property values, and improved health.”
SMALL-SCALE GREEN INFRASTRUCTURE IMPLEMENTATION:
Green infrastructure techniques are extremely beneficial on every scale. Residential homes and neighborhoods can benefit from the implementation of green infrastructure in more ways than many people realize. There are a wide variety of green infrastructure projects that can be completed with a relatively small time and financial investment. Many of us at Princeton Hydro have incorporated green infrastructure practices into our homes and properties. Here’s a look at some of those projects in action:
Dr. Steve Souza, a founding principal of Princeton Hydro, installed rain gardens throughout his property utilizing native, drought-resistant, pollinator-attracting plants. The rain gardens are designed to capture and infiltrate rainwater runoff from the roof, driveway, patio and lawn.
Princeton Hydro’s President Geoffrey Goll, P.E. built an infiltration trench in his backyard. An infiltration trench is a type of best management practice (BMP) that is used to manage stormwater runoff, prevent flooding and downstream erosion, and improve water quality in adjacent waterways.
And, in the front yard, Geoffrey installed a variety of wildflower plantings.
An interactive website toolkit was recently launched by New Jersey Future to help municipalities across the state incorporate green infrastructure projects into their communities. For this project, Princeton Hydro’s engineers and scientists provided real-world examples integrating green infrastructure into development in order to bring to light the benefits and importance of investing in green infrastructure at the local level. The New Jersey Green Infrastructure Municipal Toolkit provides expert information on planning, implementing, and sustaining green infrastructure to manage stormwater. This toolkit acts as a one-stop resource for community leaders who want to sustainably manage stormwater, reduce localized flooding, and improve water quality.
Since its inception, Princeton Hydro has been a leader in innovative, cost-effective, and environmentally sound stormwater management systems. Long before the term “green infrastructure” was part of the design community’s lexicon, the firm’s engineers were integrating stormwater management with natural systems to fulfill such diverse objectives as flood control, water quality protection, and pollutant reduction. Princeton Hydro has developed regional nonpoint source pollutant budgets for over 100 waterways. The preparation of stormwater management plans and design of stormwater management systems for pollutant reduction is an integral part of many of the firm’s projects.
Interested in working with us on your next Green Infrastructure project? Contact us here.
Tucker Simmons, Water Resources Intern
Tucker is a Civil and Environmental Engineering major at Rowan University focusing on Water Resources Engineering. He is the President and player of the Rowan University Men’s DII Ice Hockey Team. His Junior Clinic experience includes the study of Bio-Cemented sand and the Remote Sensing of Landfill Fires. In the future, Tucker hopes to work on creating a more sustainable environment. Tucker enjoys playing ice hockey, being with friends and family, and exercising.
Clay Emerson, Senior Project Manager
Clay’s areas of expertise include hydrologic and hydraulic analysis, stormwater management and infiltration, nonpoint source (NPS) pollution, watershed modeling, groundwater hydrology/modeling, and water quality and quantity monitoring at both the individual site and watershed scales. His educational and work experience includes a substantial amount of crossover between engineering and environmental science applications. He has specific expertise in the field of stormwater infiltration and has conducted extensive research on the NPS pollution control and water quantity control performance of stormwater BMPs. He regularly disseminates his monitoring results through numerous peer-reviewed journal publications, magazine articles, and presentations.