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Southern California could use single purpose grey infrastructure to help solve their water issues. While grey infrastructure is good at solving one problem, natural systems not only address the primary issue, they perform multiple services – providing co-benefits that generate broader public value.

As municipalities and regional governments transition towards a multi-purpose infrastructure, the region has an opportunity to integrate natural systems to capture and clean stormwater while also creating valuable social and environmental benefits in underserved communities.

Southern California’s Water Challenges: Quantity, Quality, & Reliability

Although an oversimplification, the region’s water challenges can fall in to three buckets (excuse the pun): water quantity, water quality, and water supply reliability.

Water Quantity

SoCal is not known for having a lot of rain in the first place, which limits the area’s ability to capture all of its water needs on-site, but given the amount of paved surfaces, when it does rain, much of this rainfall is turned into runoff. Despite the region’s vast network of dams and spreading grounds which capture billions of gallons per year, there is still room for improvement. If the water that currently flows to the ocean were cleaned of pollutants and infiltrated or directly reused, is could supply millions of people.

Water Quality

Stormwater picks up trash, bacteria, nutrients, chemicals, and heavy metals which then, if not treated on site, go in to rivers, beaches, and the ocean. These cause human health issues, hurt marine life, and degrade ecosystem functions.

Water Supply Reliability

Southern California residents rely heavily on imported water from the Sierra Mountains, the Central Valley and from states as far away as Colorado. As the climate changes, so does the predictability and variability of these alternative sources, which may disrupt supply going forward.

The Value of Nature-Based Systems

Green infrastructure (GI) has surfaced as a versatile solution for addressing the above stormwater challenges in the region. Unlike single purpose grey infrastructure, natural systems do more than tackle the primary problem at hand, generating a variety of financial, social, and environmental co-benefits beyond water quality and quantity...and, being economists, we like to put a dollar value on those impacts.

Water-Based Benefits from Green Infrastructure

Green infrastructure captures runoff and recharges the region’s groundwater, while also reducing the amount of pollutants reaching rivers and the ocean. There are financial, social, and environmental impacts that arise from this.

Other Social and Environmental Benefits from Green Infrastructure

The water-based benefits on their own may not always be enough to overcome the often-higher upfront capital cost of natural systems, which continues to be a hurdle in their wider implementation. Nevertheless, these nature-based solutions simultaneously generate a variety of co-benefits that create tangible value for a variety of stakeholders.

For example, these projects offer recreational amenities in areas that often lack green space, improve public health through exercise and reduced cardiovascular disease, they provide educational opportunities, reduce the urban heat island effect, attenuate flood risk, improve property values, as well as sequester carbon and remove harmful air pollutants.

A larger (but not necessarily complete) suite of impacts from nature-based infrastructure can be seen below.

Putting Theory in to Practice: Showing the True Value of a Project in Southern California

The team at Autocase recently valued the Triple Bottom Line impacts for a large spreading ground enhancement project – one of many green infrastructure projects currently in design in the region. This particular project will increase water conservation by infiltrating an additional 8,000 acre-feet/yr (enough to supply 24,000 homes per year) while also including landscaping, and recreation & education opportunities. The triple bottom line results help build a financial case for similar projects that integrate natural systems.

The results below are for the 50-yr lifespan of the project. Interestingly, the upfront and ongoing maintenance costs (around $59m) are outweighed merely by the financial value of water savings (around $230m). Given the large scale of the project, the social value of water supply reliability is around $60m, and the avoided emissions due to capturing water closer to the end use is valued at around $4m. Once the other social and environmental co-benefits are valued – like recreation, urban heat island, property value etc., it makes for a compelling case to invest in natural systems, with the overall triple bottom line value at almost $250m. For every dollar spent, the project is estimated to return $5.2 in benefits.

Work with Nature, Not Against it

These kinds of results illustrate that natural systems can be integrated to solve major challenges while also saving money and serving the community by creating broader public value. When assessed solely on first cost, it can be difficult to justify their implementation, but once the true value is identified, measured, and monetized, it is clear to see that these projects perform valuable social functions over and above their primary goal – often in communities that lack green space.

By valuing impacts in dollar terms, a diverse portfolio of projects can now 1) be compared consistently and transparently in an apples to apples way, 2) compete for funding, and 3) be prioritized in such a way to generate the greatest bang from the public buck.

Ultimately it’s rarely a binary choice between grey vs. natural systems i.e. the idea isn’t only to use nature or only to use grey. Instead it should be about recognizing the value that natural systems provide and integrating them in to grey solutions to enhance infrastructure projects.

This concept can be summed up nicely by E.F. Schumacher:

“Modern man does not experience himself as a part of nature but as an outside force destined to dominate and conquer it. He even talks of a battle with nature, forgetting that, if he won the battle, he would find himself on the losing side.”
E. F. Schumacher (1973). Small is Beautiful

Simon Fowell, Economist at Autocase


When CEO's of corporate giants descended on Davos for the 2019 World Economic Forum to discuss the most pressing issues facing the global economy, the topic of plastic pollution loomed large. The conference program dedicated multiple panels to transforming the plastics economy and reducing pollution.

Plastic packaging has created a crisis on global and local scales. The vast majority of plastics have never been recycled. They break down into micro-plastics, poisoning the oceans and then the soil, and ultimately enter the human food chain and without a creative action, matters will only get worse. Greenpeace and other advocates at the Forum suggested that top plastic polluters, will soon be pressured like the coal industry to make major changes, or that they might even be held liable for damages, like big tobacco was in the 1990's.

At the local level, recycling isn’t profitable for governments like it once was. Chinese processors, previously the largest consumer of low-grade recycling, are no longer as willing to purchase America’s reusable waste. As of February 2018, they began enforcing tighter standards on America’s waste, and local governments are struggling to adjust. As a result, cities are paying a hefty price to divert plastics, paper, and other recyclable goods.

This new reality has hurt communities across the country. For instance, it now costs Franklin, New Hampshire $129 per ton to recycle, whereas it used to generate $6 per ton in profit when its program first began in 2010. At $68 per ton, it’s now cheaper to just throw everything in its incinerator. At this rate, these costs will send recycling back to the dark ages of public waste disposal. To keep up, cities are investing millions to more efficiently sort materials to meet new Chinese standards and keep up with corporations changing their packaging.

In Arizona, the city of Phoenix is spending $4.5 million to update the North Gateway Recycling Facility. They are expected to recoup their investment within a couple years, according to the Public Works Department. Most of the cost—$3 million—will be fronted by a zero-interest loan from the Closed Loop Partners, a venture capital fund supported by Walmart, Johnson & Johnson, and other major corporations to finance sustainable infrastructure.

Developing local recycling infrastructure is necessary. Changing consumer and producer habits is even more important. The Closed Loop Fund also works with local governments to implement better programming that help households use less and recycle what they do use.

On the production end, Nestlé acknowledges that “half of all bottles are not recycled – a significant amount end up in landfills or as marine debris.” This past January they committed themselves to not only 100 percent recyclability in all products by 2025, retiring single-use plastics, but also developing compostable paper-based materials and biodegradable polymers with the rollout of its Nestlé Institute of Packaging Sciences.

Nestle’s strategy, like those of many other corporations, assumes a take-make-dispose model, relying on customers and local governments to recycle their products and make sure they don’t end up in a landfill, or worse. Companies like Nestle are showing they understand the environmental costs associated with their products, but a more effective approach would be to invest in the product itself—specifically, its packaging. Notwithstanding their growing concern for where their packaging ends up, companies produce packaging as cheaply as possible. With low oil prices, it is often cheaper to produce more plastic than to recycle what already exists.

An alternative paradigm is to close the loop and design products for reuse. If companies instead retained ownership of packaging, they can reduce waste but also improve the customer experience. Loop, a project announced at Davos this past January, is working with large, multinational consumer goods companies to embrace and implement new multi-use business models.

With Loop, customers order items online, put down a deposit on the packaging ($0.25 for a bottle of Coca-Cola, for example), and then buy goods at local prices, delivered to their front door. Shipping is delivered by UPS and free after a few orders. Once customers finish using products, the containers are left in a Loop-branded tote on their doorstep, picked up, cleaned, and then returned to the producer—and their deposit is returned, even if the containers are damaged. What was previously single-use packaging can now be used up to 100 times for some products.

Loop’s model is new and unproven, but there are reasons for optimism, especially given the potential for improved customer experience. Containers are cutting-edge and sleek—from metal deodorant cases to thermos-like ice cream cartridges that keep contents cold up to 36 hours. This is in addition to the added convenience of front-door delivery.

But this model of the multi-use container doesn’t have to just be for large multi-nationals. In fact, until it scales, Loop will have to ship some items across the country, from where the new packaging is made to consumers’ doorsteps. The environmental benefits of multi-use packaging could be washed out if inefficient supply chains result in high transportation emissions. Compared to lighter plastics, transporting heavier containers for beverages, for example, can require 40 percent more energy and more than quadruples costs per bottle. This might be why Loop plans to launch in only a handful of major cities for the foreseeable future.

Local entrepreneurs should see the circular, multi-use economy as an opportunity. Local milk or organic egg subscriptions could thrive under such a model—goods not necessarily needed on-demand but in constant supply. Moreover, delivery might not be best in some cases. Local stores familiar with commuting patterns and public transit could rely on the rising popularity of refill services, buy in bulk, and compete with online retailers as a convenient stop just on the way home from work, eliminating transportation costs (and emissions). Further, branded packaging and carrying bags can cultivate a loyal customer following.

With the current volatility of the recycling market, a sure-fire way to reduce plastic waste is to avoid using plastics in the first place. Multi-use packaging offers consumers a much-desired alternative and a market opportunity for any company, big or small, looking for an edge. While industry alone can’t solve the plastic pollution crisis, businesses and their customers can do their part—and stand to benefit—from moving to the circular economy.

John Trujillo

Principal at Circonomy Solutions LLC


In 2015, Xylem conducted a survey within California to study how public perception is geared toward recycled, purified, and reclaimed water. In 2017, the survey was expanded to include the general understanding of the technology used in the recycling process and the perception revolving around the ability to effectively clean and treat the water. These surveys were conducted as California was in the middle of a drought and as drought conditions eased. The results from these surveys showed that there is a majority of residents that support the use of recycled water to help bolster the water supply and help withstand future droughts that are sure to come.

From the survey it was found that three fourths of Californians are in support of adding recycled water to local supplies, and nearly 90 percent would use recycled water in their daily lives. Another finding was that respondents were more likely to support the implementation and use of recycled water in their daily lives if reduced costs and rebates were given to those who opted to receive it. Stemming from the additional 2017 survey, around 75 percent of Californians fully trusted the treatment process of recycled water after being educated about the processes and technology behind it. Within the City of Los Angeles, LA Sanitation is spreading the word that recycled water is safe and it is coming. With over 88 million gallons per day of recycled water produced currently the city is on track to reach its goal of reducing imported water and using 50% locally sourced water by the year 2035. This will be fully achievable through the use of recycled water.

Support continues to grow for the goal of sustainability and utilizing recycled and locally sourced water. Water and wastewater utilities have the responsibility to ensure that globally there is access to clean and safe drinking water for all. LA Sanitation, back by the City of Los Angeles, is on track and leading the way to securing that sustainable source of water for current residents and future generations to come.

Michael Simpson
Public Works LA
Principal Environmental Engineer


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)

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