Our education at UBC has an intentionally fragmented setup which might make it challenging for us to see the interconnections between the various fields of Civil Engineering, and the opportunities available for us, as Engineers to optimize the systems for an ecological and human benefit. Green Infrastructure is one of the primary topics covered in CIVL 498A. It is a very broad concept spanning various fields of Civil Engineering from Transportation, to Structural Engineering, to Stormwater Control. Various components of GI are shown in Figure 1 below.

This blog post summarises the issues surrounding scientific research of Green Infrastructure (GI), as covered in detail here. It is meant to be a compliment to the article, and I highly recommend reading the article in its entirety. The following are the challenges in studying GI from a research perspective.

·        GI features and/or elements

GI encompasses a wide variety of areas from ponds, to green roofs to bee hives (as shown in Figure 2). Monitoring the effects of these GI elements is difficult, if not impossible. GI elements such as green roofs are easier to study and monitor, and hence, garner more attention.

·        Cost and benefits of GI

Costs are divided between the Financial costs & Opportunity costs. The resources used on constructing the GI elements are considered Financial costs. The benefit that would be obtained from those resources spent elsewhere would be considered the Opportunity cost. GI is most effective when thought of while improvements in present infrastructure are being made. For example, incorporating wildlife corridors when overhauling a highway system.

Benefits of GI are more qualitative than quantitative. Some indicators of GI benefits are: the quality of green spaces, the amount of sequestered carbon, the increase in employment after GI implementation. Figure 3 below attempts to describe the qualitative values of GI.

·        Evaluating GI

The main goal of GI is the protection of ecological functions while simultaneously benefiting humans. When a GI element does not provide one of the two, or favors one over the other, that is an indicator of a poorly designed GI element. Policy, guidelines and standards are needed before any serious evaluation of GI can be undertaken.

·        Multi-level evaluation

Since GI can be of different scales, it might be more effective to take a Systems Thinking approach. Additionally, analyzing not just the GI alone, but the institutions that manage (government agencies, etc) and use (transportation agencies, etc) these systems should be undertaken.

 Conclusion

I believe that bringing to light the challenges in studying GI will lead to development of qualitative as well as quantitative methods of measuring GI impacts. As future Engineers, by knowing these challenges, we might be able to better justify implementing GI in our projects when posed with questions about their benefits.

 References:

Figure 1

Figure 2

Figure 3

T O P I C   O V E R V I E W

This week I decided to read a selection of the book “Sustainable Infrastructure : The Guide to Green Engineering and Design” by S. Bry Sarte. This reading investigated  applications of sustainable infrastructure and explored several case studies in order to demonstrate these applications. I found the case study of development on Isla Pedro Gonzalez (known locally as Pearl Island) in the Gulf of Panama to be particularly interesting. As the book discusses, islands make great examples for sustainability case studies as it is easy to see and appreciate that resources are limited, and to define the system boundaries. One can clearly observe the effort required to transport resources to and from the island, and see the trash piling up on the island’s beaches and in surrounding waters.

Pearl Island is unique in that a master plan for development on the island was developed by a team of local residents and stakeholders, engineers, ecologists, architects, and community planners prior to significant human habitation, development, and use. This allowed the island to be developed sustainably from the ground up with all environmental factors considered, without having to modify an existing poorly developed site. Many interesting and useful design strategies were employed in throughout the development of the master plan and are discussed at length in the book. However, I found the idea of an “Index of Ecological Importance” particularly intriguing.

Figure 1: Looking out towards Isla Pedro Gonzalez (Pearl Island) in the Gulf of Panama

The index of ecological importance is a design approach developed as a starting point for understanding the relative value of the green infrastructure system on a project site. The intent of the index is to provide an overview of these conditions and opportunities, identify areas which are most critical (no development allowed) and critical (employ environmentally responsive design techniques), and to establish a framework for biological connectivity between these areas and the surrounding area. Once developed, the index is then used to inform all other development plans, and as a general guide through the master planning process – focusing development with greater impact away from critical habitats, and ecologically sensitive areas. In order to ensure they achieved the most accurate model possible, as the project team for Pearl Island’s understanding of the island’s ecosystems improved, the index was continually updated and re-evaluated. Looking forward to future projects, I think this list could be expanded to include areas which provide ecosystem services in order to minimize their loss through to human development and preserve critical ecosystem functions.

In order to develop an index of ecological importance, a decision matrix is created which assigns relative value to specific known physical and ecological conditions on the island (or any subject area). Ecological data such as slope analysis (to asses the impact of deforestation on slope stability and resulting dirty surface runoff into surrounding bodies of water), a vegetation survey, existing development, waterways, and mapping of critical bird and wildlife habitats can be included as the analysed data sets. This sets of data are then weighted by relative importance and layered to for a single map of ecological importance for the subject area. This transformation of the environmental data and relative comparison of ecological importance into a physical space can be used to inform decisions regarding the impact and placement of buildings, infrastructure, and other development. An example of this map or index of ecological importance for Pearl Island can be seen below.

Figure 2: Index of Ecological Importance on Pearl Island. Darker areas are most critical.

 

S U G G E S T E D   A S S I G N M E N T

In order for students to learn about the concept Indices of Ecological Importance an assignment such as the following could be completed.

Part One: Reading

Students would be asked to complete a reading on Indices of Ecological Importance. Pages 300-302 of S. Bry Sarte’s Sustainable Infrastructure : The Guide to Green Engineering and Design would be appropriate.

Part Two: Questions

Students would be asked to complete the following questions:

1. In your own words, summarize the concept of Indices of Ecological Importance in a few sentences.
2. What are some of the benefits of this approach?
3. For which types of projects would this approach be most appropriate?
4. Are there projects where this approach would not be appropriate? Explain.
5. Name at least two ways in which this design approach could be improved.

Part Three: Create an Index of Ecological Importance

Students would be given a sample area and development project for which to create an Index of Ecological Importance. A map of the area would be provided. Students would be expected to come up with a list of at least ecological conditions or data sets, and then create a decision matrix to weigh the relative values of these criteria. Finally, students would be asked to create a rough map of the ecological importance of the site based on their decision matrix and the map provided.

 

R E F E R E N C E S

Sarte, S. B., Mr. (2010). Sustainable Infrastructure: The Guide to Green Engineering and Design. Hoboken, NJ: John Wiley & Sons.

 

 

 

 

LEED Neighbourhood Developments emphasize the practice of LEED on a larger scale (see video below for an example from Tampa, FL). These neighbourhoods are able to provide a connection to both natural ecosystems and human ecosystems by creating and incorporating urbanism, green building and smart growth.

 

 

The benefit of these developments is that they create communities focused on reducing green house gas emissions for an overall larger environmental goal as “buildings generate up to 35 per cent of all greenhouse gases, 35 per cent of landfill waste comes from construction and demolition activities, and 70 per cent of municipal water is consumed in and around buildings” (Canada Green Building Council, 2016).

 

 

Sources

Canada Green Building Council (September 20, 2016). Going Green with LEED. Retrieved from http://www.cagbc.org/CAGBC/LEED/GoingGreenLEED/CAGBC/Programs/LEED/Going_green_with_LEE.aspx?hkey=01b3d086-d0a4-42cf-9e61-7830d801c019