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The City of Phoenix wanted to weigh up the broader costs and benefits of implementing various Low Impact Development (LID) features across the city to help inform capital planning going forward. To do this, they enlisted the help of Stantec, Autocase, and Watershed Management Group (WMG) to perform a triple bottom line cost benefit analysis (TBL-CBA).

Using Autocase’s online TBL-CBA platform, the impacts listed in Table 1 were quantified for each of the LID features and then compared against a traditional concrete base case on a per-1,000 sq. ft basis.

At a high level, the results in the table below show that LID features generate positive triple bottom line benefits. On a pure lifecycle cost, we find that Infiltration Trench is the only feature that is cheaper than Concrete – costing almost $2,000 less per 1,000 sq. ft. However, compared to concrete, every LID feature (other than Pervious Pavers) generates enough social and environmental benefit to result in a positive TBL Net Present Value (NPV).

Since runoff does not get treated by a wastewater treatment plant, given that Phoenix has a separate storm sewer system, water quality was a major concern for the City. Instead, runoff passes through either a hydrodynamic separator or a filter catch basin insert before going in to the storm system.

LID can positively influence the water quality in a local area by reducing surface runoff of pollutants. We estimated the value of improved water quality by first modeling the reduced runoff that would be passing through these grey systems due to having LID present on the site. We then equated this resulting reduction in runoff to an avoided capital expenditure and operations & maintenance costs for the grey systems. The water quality results for each LID feature is given in the table below. It is clear that they contribute significant value to the overall TBL results.

Multi-account analyses like these not only answers the questions of “What are the benefits?” and “Who are the beneficiaries?”, but equally important, “How much do they benefit?”. Putting everything in dollar terms allows comparison on an apples-to-apples basis and helps build consensus to the delivery of projects while creating an evidence base to promote a shared responsibility to capital planning for these non-traditional projects.

Simon Fowell
Autocase (by Impact Infrastructure)


Fairfax County, Va., is subject to the same stormwater problems encountered by municipalities across the nation: aging infrastructure; increasingly stringent regulations; degraded streams; litter; and limited funding.

Faced with these challenges, the county’s Department of Public Works and Environmental Services is developing a comprehensive, sustainable asset management program to effectively operate, maintain, and reinvest in its stormwater conveyance system. The new asset management program helps identify risks before failure occurs, which enables staff to prioritize maintenance and optimize reinvestment.

Prior to developing the program in the Stormwater Infrastructure Branch, service requests were generated from citizen complaints for problems such as sinkholes, blockages, flooding and erosion. “The complaints we receive give us an opportunity to assess the problems particular to stormwater,” said Branch Chief Val Tucker, P.E.

Technicians perform condition assessments through walking surveys and with pole cameras, recording findings in GIS. They’re also using CCTV cameras to obtain videos of defects within the pipes. “We find off-set joints and holes along with intrusions and unauthorized connections that must be removed,” Val said. “We see utility lines in the pipes. There are downspouts, sump pumps, and other plumbing intrusions, and there are break-ins by fence posts, guardrails, and utility poles.”

The three teams (condition assessment, closed system and open system) work together to keep stormwater flowing and to achieve water quality benefits. In addition to sediment and litter, pipe-cleaning crews find animals and tree roots in the pipes.

The county’s asset management program is achieved through:

  1. An inventory of assets (Fairfax County manages 1,300 miles of pipe, more than 62,000 storm structures, and 100 miles of improved channels and outfalls).
  2. A condition assessment of the inventory.
  3. Considering risk and prioritization: Can the operations and management investment be optimized? Is reinvestment needed, necessary or urgent?
  4. Predicting future needs and creating a funding strategy.  

As of October 2017, approximately 75 percent of the county’s pipes have been inspected and assessed. Some are in good shape, about 3 to 5 percent require attention. The remaining 25 percent are scheduled to be assessed within the next two years.

Where possible, rather than replacing pipes, staff renews them using cured-in-place pipe liner techniques, which saves time, money, and trees and disruption to adjacent properties.

Finally, using natural channel design improves water quality by reducing erosion and excess nutrients, which earns the county Total Maximum Daily Load (TMDL) credit toward compliance with its Municipal Separate Storm Sewer System (MS4) permit. The asset management program allows the stormwater infrastructure team to proactively identify problems before they develop into safety concerns, negatively impact residents or threaten the environment.

Irene Haske
Information Officer
Fairfax County Department of Public Works and Environmental Services


As communities invest in developing multi-modal transportation systems, improvements to facilities for people walking and biking can often be delayed due to the construction costs and environmental impacts of elements such as street widening to accommodate bike lanes and sidewalk construction.

As public works professionals one of our core responsibilities is to leverage our existing assets to safely and efficiently serve our communities. The question of how we allocate our rights-of-way may be our greatest opportunity to leverage existing assets to provide additional transportation services.

The Federal Highway Administration (FHWA) has developed a number of guidance documents which illustrate ways to leverage existing street space to serve people walking and biking while providing safe and convenient facilities for people driving.  Most of the treatments consist of signs and markings coupled with thoughtful design and outreach to your communities.

The first resource from FHWA, “Incorporating On-Road Bicycle Networks into Resurfacing Projects” discusses practical ways to change the configuration of streets while performing pavement preservation projects. At the City of Eugene this approach has been one of the most impactful ways of adding or improving bicycle facilities within our City.

The second resource, “Small Towns and Rural Multimodal Networks”, while created for transportation professionals in small towns and rural counties, also provides examples of treatments that may be appropriate for narrow city streets. One innovative concept known as “advisory shoulders” or “advisory bike lanes” is particularly applicable for low volume, low speed streets with good sight distance.

Advisory shoulders takes an existing narrow two-way street and allocates usable shoulder space on each side of the street ,delineated by a skip stripe, and a center lane used by two-way motor vehicle traffic. When no bicyclist or pedestrian occupies the shoulders people driving can use the shoulders to safely pass oncoming vehicle traffic.  An example of this configuration can be seen below.

While advisory shoulders are used widely in European countries such as the Netherlands they are relatively new to the United States. Currently an approved request to experiment is required from FHWA to install advisory shoulders.

This concept is further explored by Alta Planning and Design in their white paper, “Advisory Bike Lanes in North America”.

So next time you are scratching your head about how to help improve walking and biking in your community without breaking the bank, browse to these resources to find low cost best practices to help your community meet their goals to provide safe and cost effective transportation options.

Please use the links in this article to access copies of these resources at the C4S Sustainability Toolkit.

Matt Rodrigues
Chair, APWA Center for Sustainability (C4S)
Principal Civil Engineer, City of Eugene


Whenever municipal staff are moving forward with a capital project or a masterplan, a critical component of the process is the input from the public. Past practice has been to book a meeting room in City Hall, advertise the event, set up display panels, recur city staff to man the stations and roll out the coffee and cookies table. Then patiently wait for the public to come out in droves. However, it usually ends up with a small dribble of people who have an axe to grind on the project. So where is the silent majority who support the project and how do you secure their input.

So, when you are asking people what it would take to get out of their car and onto a bike, City of Victoria Transportation staff took up the challenge themselves and decided to hit the road to their first open house…by bike.

Open houses are designed to be interactive and educational and staff try to pop-up in neighbourhoods across the city.  Their aim to “go to where the people are” and we generally bring a lot of stuff with them. Picture: handouts, buttons, a survey box, three easels, a canister for the biking map, a small folding table, a trivia spinning wheel and three display boards.  Insert: A bike trailer.

With the trailer in hand, a few bungy cords and a new cheery orange safety flag, it was time to start packing.  Most of the supplies did fit.  However, the colorful trivia wheel was deemed a bit too large for a first trip and the display boards were a few inches to wide but generally it all fit.

Social media was used to promote the open houses and provide feedback to the public on the results.

Several very successful pop-up meetings were held in various neighborhoods with input from cycling users, pedestrians and adjacent neighbors. Staff set an excellent example reducing their carbon footprint and showing that those who are affected by a decision have a right to be involved, which lead to a broader community involvement.

The City of Victoria is currently working to update the Bicycle Master Plan.  Victoria’s first ever Bicycle Master Plan was created in 1995 and has guided the development of Victoria’s cycling infrastructure since then.  The updated Bicycle Master Plan will consider changes that have occurred in Victoria over the last 19 years, including a growing interest in cycling, an expanded regional cycling network, plans for future growth and new regional and City plans and policies. More information on the process and project can be found at

Dwayne Kalynchuk

Director of Public Works & Engineering City of Victoria


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