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Environmentally Significant Areas


What is it?

Environmentally Significant Areas (ESAs) are areas that are important to the long-term maintenance of biological diversity, physical landscape features and/or other natural processes, both locally and within a larger spatial context. Delineation of ESAs is usually accomplished by combining numerous data sets representing (e.g.) focal species habitat, significant geological features, valued aesthetic environments, soil conservation opportunities, air filtration capacity, and other associated benefits.

How can municipalities use it?

Environmentally Significant Areas (ESAs) can be a critical element informing numerous other municipal tools for maintaining natural systems. ESAs can provide direction for protection efforts such as conservation reserve dedication, conservation easement acquisition, or purchase of ecologically-important lands. ESA maps can be placed directly in an MDP, and inform several subsequent efforts including parks/natural area/open space planning, Area Structure Plans, and growth management plans. ESAs can also trigger needed refinements, signalling where developers need to undertake detailed environmental inventories or assessments, or where protection needs to take precedence over recreational uses, requiring buffering between pathways and ESAs.

Alberta municipalities may designate ESAs themselves, or may use the Government of Alberta ESA layer. When identified prior to development of land-use plans, the conservation of these lands can be incorporated into land use decisions.

What are the advantages?

There are many advantages of using ESA information, including:

  • Government of Alberta ESA layer pre-exists and covers all municipalities

  • Can proactively identify areas of importance before development planning happens

  • Can wrap several natural system features into a single spatial representation

  • Multi-faceted combination of datasets can still be divided out for consideration of individual natural system elements

What should you watch out for?

No tool is a silver bullet. There are issues for municipalities to watch out for with Environmentally Significant Areas, including:

  • An ESA designation does not mean these areas are protected; can lead to unwarranted nervousness on the part of developers, and unwarranted security on the part of conservationists.

  • Generally a coarse-scale tool, requiring refinement at the site-specific scale

  • Needs to be updated regularly to remain useful

How can it help maintain natural infrastructure?

Environmentally Significant Areas (ESAs) help to maintain the natural infrastructure system by identifying the elements of the system (natural features, natural infrastructure assets), creating a proactive way to incorporate their existence into planning, facilitating their protection, and ensuring their functions and benefits are considered from the MDP on down.


Environmentally Significant Areas of Alberta Volumes 1, 2 and 3 – Evaluates and provides an overview of all ESA inventories completed until 1997 in Alberta and to determine which areas were of provincial, national or international significance.

City of Hamilton Proposed Natural Areas Acquisition Fund Strategy – submitted by the Hamilton Planning and Economic Development Department to set aside funds annually for the acquisition of Natural Area lands. The general purpose of a Natural Areas Acquisition Fund Strategy is to outline the requirements for the implementation of the Natural Areas Acquisition Fund. It provides details on the suite of securement tools available for landowners who have natural heritage system lands located on their property. It also provides a framework for determining the natural heritage lands that would be suitable for acquisition by the City of Hamilton, and fosters relationships with Hamilton partners that currently participate in the securement of natural heritage system lands within the City of Hamilton. This document includes a section on Environmentally Significant Areas.

Green Bylaws Toolkit: for conserving sensitive ecosystems and green infrastructure – This document is an important resource for understanding how municipalities and developers can safeguard the environment, from a regional to a site level. It clearly explains each tool, and provides case studies and examples of bylaws that are in use in British Columbia. Mapping of ESA’s is used to obtain baseline data to aid in protection of these areas.

Did we miss something?

If you know of a resource that should be on this list - or your municipality has a sample or case that should be here, please let us know!

Thanks for helping us out!

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