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Using GIS to Identify and Prioritize Community Brownfield Redevelopment Sites


by Scott Mattes, PE, CIH, Environmental Services Group Leader, HR Green and Pete Lovell, Project GIS Specialist II, HR Green

Coined less than 25 years ago, the term “brownfields” is relatively new to the environmental science lexicon and remains unfamiliar to many outside the profession.   Few realize that, since 1995, the United States Environmental Protection Agency (EPA) has overseen a program devoted to improving these unpleasant-sounding places. 

Brownfields are defined by the EPA as “real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant.”  Cleaning up and reinvesting in these properties increases local tax bases, facilitates job growth, utilizes existing infrastructure, takes development pressures off of agricultural land and greenspaces, and improves human health. 

Brownfield redevelopment is a multi-phased, multi-stakeholder undertaking that involves a property being assessed; its future use considered by a wide array of interests (e.g. community members, local governments, the private sector, environmental regulators), mindful of the constraints imposed by local land use and zoning restrictions; and it being remediated, redeveloped, and ultimately put back into productive use.

The EPA estimates that within the U.S. there are more than 450,000 brownfields.  Yet, identifying, categorizing, and prioritizing which of these sites are most worthy of federal and state funds can be a daunting task. Geographic Information Systems (GIS) can make this task easier, but simply creating a “pretty map” is not going to provide the depth of analysis needed to thoroughly consider and prioritize the many thousands of parcels within a community.

Developing a GIS Prioritization Model

HR Green has moved beyond a pretty map to developing a GIS Prioritization Model that identifies potential brownfield properties and scores them based on environmental risk and redevelopment potential.  This model seeks to assign higher redevelopment scores to properties most likely to be desirable to developers as ‘shovel-ready sites’ following cleanup.

The HR Green GIS model is a critical component in HR Green’s comprehensive approach for identifying brownfield redevelopment opportunities.  The GIS model is robust enough to give full and equal consideration to every parcel in a community.  Thousands of city parcels are systematically evaluated against dozens of environmental and redevelopment GIS map layer criteria as a part of this automated model.  The model performs a consistent, thorough analysis that could not be accomplished within project time and budget constraints via a manual process.  

The GIS model has two objectives:

1) The first modeling objective involves mining the environmental data to determine what community properties exhibit brownfield potential.  Again, revisiting the EPA definition, HR Green is seeking to find those properties with “the presence or potential presence of a hazardous substance, pollutant, or contaminant.”  Without meeting this basic definition, no EPA funds can be expended on a property. 

That said, not all properties meeting this minimum definition show the same level of environmental risk.  For example, one property may be identified because of a single potential source of contamination that is located so far off-site that the property barely falls within its zone of risk.  Another property, on the other hand, may have a myriad of environmental concerns on-site, ranging from illegal dump sites to leaking underground storage tanks to former mines.  The GIS Prioritization Model not only identifies at-risk properties but also scores them by the potential severity of their environmental concerns.

2) The second modeling objective is to evaluate properties for their future development potential.  Many considerations factor into redevelopment potential.  Is a property located nearrequired utilities (sewer, water, electric, fiber, etc.)?  Does a property have adequate area for the desired reuse?  Does a property fall within a community district identified for urban renewal?  HR Green’s GIS model examines these criteria and many more in generating scores that assess the redevelopment potential for every community property. 

These results are then delivered to HR Green environmental scientists and, ultimately, to community stakeholders, who study and scrutinize the highest-scoring properties in detail to arrive at a list of properties for the community to pursue.  This “ground truth” review depends on environmental professionals and community stakeholders using their expertise to go beyond the model results, often applying local knowledge in determining property suitability on a case by case basis. 

In summary, the HR Green approach to identifying favorable brownfield redevelopment properties can be divided into three parts:

1) Environmental Risk – A defensible approach identifies:

i. environmental risk

ii. available funding from the EPA to perform an environmental site assessment

iii. how to move forward on clean-up.

A proven GIS Prioritization Model can evaluate every parcel in a community for environmental risk, filtering out those showing no risk and scoring the rest based on the cumulative risk posed by a variety of different environmental criteria.

2) Redevelopment Potential - Theredevelopment potential of a site is also taken into consideration and scored by the GIS Prioritization Model.  Proximity to major transportation corridors, water service, and fiber optic networks are a few of the many redevelopment factors examined by a robust GIS model in generating each parcel’s redevelopment score.

3) Ground Truth - The final part of a complete approach enlists the expertise of environmental professionals and local stakeholders.  While a GIS model can process and help make sense of enormous amounts of data, members of a community are the experts when it comes to knowing if a site has a distinct historic value or if it already represents a thriving business place.  The unique priorities of a community are given particular weight in this ground truthing process.  While one community may prioritize economic development foremost, another might be motivated to clean up properties with a focus on public safety and the overall health of the community.

The City of Dubuque, Iowa, is one of several communities that have adopted this approach for identifying promising brownfield redevelopment opportunities.  HR Green created a custom GIS Prioritization Model that examined every land parcel within Dubuque.  The model scored these parcels based on their environmental risk and redevelopment potential.   Over 26,000 parcels were analyzed, 6,413 of which were found to have potential environmental risk.  Based on model results and a review of high-scoring parcels by HR Green environmental scientists, 62 candidate sites were brought forward for consideration at a meeting with City stakeholders.   Following discussions with City officials and community stakeholders, 26 of these sites were selected and are in the process of being assessed prior to future clean-up and/or redevelopment.  Dubuque citizens can currently follow the project’s progress on a site by site basis by visiting the City of Dubuque’s brownfield redevelopment web mapping progress portal.

The GIS Prioritization Model and the information it produces can continue to be an important resource for communities like Dubuque well after providing the basis for an initial roadmap.  The automated GIS model is repeatable and flexible - easily accommodating new criteria, criteria weights, and data sources - allowing the analysis to be revisited as community data and priorities change.  In some cases, the GIS Prioritization Model not only proves influential in prioritizing redevelopment but also in increasing the adoption of GIS within the community.

As a powerful application of GIS, HR Green’s Prioritization Model demonstrates the workflow efficiencies and decision-making capacity that a well-considered GIS can deliver, not only for brownfield redevelopment but also for asset management, engineering design, and other community initiatives. 

Co-Authors:

Scott Mattes, P.E., CIH

Pete Lovell

Environmental Services Group Leader/Senior Project Manager               

Project GIS Specialist II

Governmental Services State and Local – Midwest

Governmental Services State and  Local – Midwest

Contact: smattes@hrgreen.com

Contact: plovell@hrgreen.com

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