Urban Sustainability & Climate Change

SESSION E: Urban Sustainability & Climate Change

Session Chair: Nick Sabatine, Ransom Consulting, Inc.

Session Description: Although Maine is best known for its rural character, the state does have urbanized areas that date back several centuries. Problems associated with past industrial usages, aging infrastructure, and stressors like changing weather patterns have brought new vulnerabilities to our attention. What are some of these vulnerabilities and how do they affect the sustainability of urban areas and our built infrastructure? New knowledge and techniques are needed to sustain Maine’s built environment and diverse economy to help make us resilient to change and future extreme events. In this session we will look at some of the solutions to these problems that include many pieces that link across the landscape.

Presentations Available

Session Overview

8:30 – 8:55 am
The Power of Brownfields Redevelopment for Enhancing Sustainability, Resource Protection and Economic Growth in Rural Maine
D. Todd Coffin, WCCOG Brownfields Program, Woodard & Curran, Inc.
Judith East, Washington County Council of Governments

Rural Maine is highly dependent on private water supplies, is host to the watersheds of Maine’s wild Salmon Rivers, and is world-renowned for timber, blueberries, potatoes, lobster and recreation. All are inexorably linked to the health of the environment. Rural Maine also represents some of the most economically depressed areas of the State and Region, raising the stakes for the sustainability of this natural resource-based economy. For over a decade, redevelopment of underutilized commercial and industrial properties, or Brownfields, has been a cornerstone of economic growth in the state, from the western mountains to the Downeast coast. This presentation explores the powerful role of Brownfields redevelopment projects in protecting the environment, sustaining resources, and bolstering the economy of rural Maine. Case studies will be shared that highlight drivers for redevelopment in rural Maine, solutions for funding where dollars are scarce, and outcomes that raise the spirit.

9:00 – 9:25 am
5’ High and Rising: A Case Study of Determining Maximum Water Elevations in Tidal Rivers During 1% Annual Chance Coastal Storms
Leila Pike, E.I.T., Ransom Consulting

The downstream reaches of tidal rivers, and the river infrastructure within, will feel the effect of increasing storm frequencies and intensities brought on by climate change. This is a case study of determining flood levels within the downstream reach of the Kennebunk River during coastal storm surges, specifically 1% annual chance storms. HEC-RAS was used to create a river circulation model that incorporated mean annual freshwater flows and a variable head boundary at the mouth of the river representing total water levels during a hypothetical 3-day “Northeaster” storm. The reversible flow model allows for the simulation of a build-up and dissipation of the surge with superimposed wave setup. Total water levels at the mouth of the river were calculated by estimating surge elevations based on tide gage data from past storm surges and adding wave setup calculated using SWAN1-D, a modeling software which incorporates wave attenuation along a long wave ray from deep water to the limit of the wave setup on land. Mean annual freshwater flows were determined by applying USGS regression equations. To complete the analysis, an STWAVE model was used within the river to account for the wave crest elevation above the maximum 100-year surge elevation in the river. The end result shows maximum water levels within the river as well as the effect of river constrictions on the flood flows.

9:30-9:55 am
Pipe Dreams: Balancing Risk, Benefit and Cost for Workable Culvert Design
Charles Hebson, P.E., Surface Water Division, Maine DOT

MaineDOT is on the frontline of dealing with climate change impacts. Inland assets such as bridges and culverts are the hard interface between infrastructure, climate and hydrology, while coastal structures are directly exposed to sea level rise and storm surge. Dealing with climate is fundamentally a decision-making exercise: how to allocate scarce resources most effectively with incomplete and uncertain information over a wide spectrum of asset criticality and vulnerability. MaineDOT has taken up this challenge on several fronts, by sponsoring ongoing research and data collection by USGS, participating in FHWA pilot programs, and developing new design policy that addresses the risk associated with climate change. Culverts present a particularly thorny problem: there are many thousands of them and they do not command the resources that are routinely assumed for larger bridge structures. MaineDOT is currently developing new culvert design policy that identifies risk, benefit, cost, and environmental aspects for these smaller structures, in the context of the limited resources that are available for these smaller structures. The resulting policy should benefit towns as well, since Maine municipalities own untold thousands of structures. This presentation will discuss MaineDOT’s framework for culvert design that directs resources to where impacts of changing hydrology are most pronounced, as opposed to a blanket system-wide program of upsizing.

10:00-10:25 am
Translating Dreams to Reality: Assessing Risk in an Unpredictable World
Judy C. Gates, Director, Maine DOT Environmental Office

In 2013 MaineDOT and several other DOTs from around the country undertook Climate Vulnerability pilot projects funded by the Federal Highway Administration. These pilots were focused on developing and implementing tools that to help identify critical transportation infrastructure and prioritize vulnerable assets in the face of rising sea levels and increasing frequency and intensity of coastal storm surge events. A year later MaineDOT has submitted its final report and it points to some speed bumps in reaching our collective goal of climate resiliency. According to our analysis, local hydrology, topography, and tidal and storm surge regimes demand a site-specific approach to benefit-cost analysis of alternative engineering structures. This is contrary to revealing a concrete design standard that, uniformly applied, would result in more resilient coastal infrastructure. Comparing different design solutions for each asset at the conceptual design phase poses not only the typical challenges associated with under-funded planning efforts, but may not even be feasible in the same timeframe as decisions on budgets and scheduling due to fiscal uncertainties. Site-specific analyses are data-intensive and our collective resources are spread thinner all the time, so it’s critical to know that the information we are collecting is not only meaningful, but useful in decision-making. Our pilot results have led us to re-evaluate how MaineDOT might undertake climate-related, risk-based asset management with a two-step, “no regrets” approach that considers landscape context as well as structure-specific vulnerabilities.