The evolution of stormwater management has come full circle with a renewed focus on nature-based infrastructure solutions to address impacts of urban development, drinking water source protection, and more intense and more frequent storms. There are many case studies highlighting the positive impacts of “greening” our stormwater infrastructure. So why isn’t everyone using it?

If green infrastructure can provide comparable benefits to gray infrastructure at reduced costs, then the financial case can be made for investing in the conservation, sustainable management, and/or restoration of natural ecosystems to achieve development goals. Yet many factors push developers, engineers, and municipalities to more traditional gray infrastructure solutions. Hybrid approaches, utilizing a combination of green and gray infrastructure, may provide an optimum solution.

This session will highlight projects that demonstrate the economic, environmental, and public health values provided by choosing green infrastructure while presenting the decision matrix for a balanced green and gray approach.

Session Co-chairs:
Dan Diffin, P.E., LEED AP BD+C
Sevee & Maher Engineers

Tamara Lee Pinard
Community Initiatives Manager, The Nature Conservancy

Session Speakers:

8:30am-8:55am
Green Infrastructure Benefits Exposed: Lessons from Municipal Implementation
Martha Sheils, New England Environmental Financing Center; martha.sheils@maine.edu

Stormwater is often seen as a burden, but it can also be a valuable resource that provides numerous opportunities and benefits to communities. This presentation will explore a change in our approach to managing rainfall as a problem to be collected, treated and disposed of, to an opportunity that can provide numerous community, environmental, and financial benefits. Highlights include GI installments designed in cooperation with local municipalities that are less expensive, adaptable, with lower maintenance burdens and measured performance rates.

9:00am-9:25am
Balancing the Green: Vision for Meeting Portland’s Infrastructure Needs
Nancy Gallinaro, City of Portland; neg@portlandmaine.gov

As a coastal community, Portland is at the end of the pipe for all drainage. With water virtually surrounding our city and five streams that do not meet state water quality standards, we recognize that water is a challenge to manage, but we have also come to see it as a valuable resource.

This presentation will highlight the balanced approach that Portland has employed to address its deteriorating infrastructure. We are working to incorporate stormwater treatment into all of our sewer separation and CSO abatement projects. We use green infrastructure when feasible and grey infrastructure treatment options when it’s not. Project examples and lessons learned will be showcased from multiple years of implementation and maintenance. The bottom line is that without reliable infrastructure, the City cannot promote development.

9:30am-9:55am
Green or Grey Solutions? Why not both? Lessons from the Mid-Atlantic on Hybrid Living Shorelines
Jesse Baldwin, GZA GeoEnvironmental; Jesse.Baldwin@gza.com

As concern for coastal flooding and shoreline erosion rises with sea levels, government agencies and municipalities in the Northeast have become more interested in Natural and Nature-Based Features (NNBFs), including Living Shorelines, in lieu of monolithic hard solutions. NNBFs and Living Shorelines provide natural resource, habitat and recreational benefits, but also play a key role in shoreline protection and flood management. Both Connecticut and New York have enacted legislation supporting alternatives to traditional shoreline armament such as bulkheads and seawalls. While recent debate in the Northeast about green or grey solutions often advocates for one approach over the other, Mid-Atlantic states have long advocated the use of hybrid solutions combining both green and grey design elements to achieve shore protection and habitat restoration simultaneously. This presentation will discuss the benefit of hybrid living shoreline approaches and where their application is most appropriate. Hybrid Living Shoreline project examples will also be presented including a Shoreline Restoration Project in Cape Charles Virginia which turned an eroded beach with a seawall into a recreational beach through dune creation, vegetative plantings, beach nourishment and stone breakwater construction.

10:00am-10:25am
Trees, Not Treatment: Conserving Forests is a Natural Method of Water Treatment
Paul Hunt, Portland Water District

The Portland Water District (PWD) supplies drinking water to 200,000 people in 11 Maine communities. Its source is Sebago Lake – a large, multi-use lake with excellent water quality. The water quality of the lake is largely a result of the predominantly forested watershed, as well as the depth and geology of the lake. Due to the exceptional raw water quality, PWD was granted a waiver to the filtration requirements of the Federal Safe Drinking Water Act – in part because there is so little in the water to filter out. So, in essence, the first step in the natural treatment process occurs in the forests upstream of the lake. However, the vast majority of watershed land (approximately 91%) is privately owned and unprotected.

As the Greater Portland area grows and development moves further into the watershed it threatens the ability of the forest to continue producing exceptionally clean water. It is difficult to predict how climate change may influence functioning of the forest-water system but the safest strategy is to conserve the forest to the extent practicable.

By providing conservation grants to individuals, land trusts and other organizations seeking to conserve forested land, PWD is helping to keep the forest intact so that it can continue serving as a natural filter for years to come.