In school we all learned about the water cycle — lakes and streams, evaporation, clouds, rainfall.
In school or as adults we also learned about the urban water cycle: surface or groundwater, drinking water, wastewater, discharge.
These cycles portray water as a single resource or system, and yet in daily life we tend to think of water’s various forms or stages as separate entities. To cite just one small example, in my home community of Two Rivers, Wisconsin, stormwater and wastewater are separate divisions under the Department of Public Works, and drinking water is in an entirely different department — under utilities, with electricity.
How would things be different if we started thinking of water in all its manifestations — precipitation, lake, river, groundwater, stormwater, wetland — as a single resource? That’s the principle behind One Water, a concept rapidly gaining acceptance.
The core idea is that we could manage water more efficiently and sustainably, and deal more effectively with water issues — quality, reliability, availability, affordability — if we thought of water more holistically.
House divided
Consider for a moment how we look at water on the macroscopic scale. We have separate industry associations for wastewater (WEF), drinking water (AWWA), stormwater (National Municipal Stormwater Alliance) and groundwater (National Ground Water Association).
To be sure, those areas have needs and issues of their own, but the obvious thing they have in common is that they deal with the same resource, and in various ways they are interconnected.
Traditionally, in many communities, the objective with stormwater, whether from rain events or snow melt, has been simply to make it go away. In my hometown, that meant collecting it and piping into the rivers or Lake Michigan.
To illustrate the trouble with such an approach, look to California, which last winter saw massive snowfalls. Some of that snowmelt ended up in rivers that communities could tap for drinking water and farmers could draw upon for irrigation — this could help alleviate supply shortages from years of drought.
But some of the water ended up threatening floods or simply flowed into the Pacific Ocean. What if infrastructure had been in place to capture more of that melt water for irrigation, drinking water and industrial processes?
Taking action
The One Water concept is not entirely new. The recycling of wastewater is an excellent example of water being treated holistically.
In many communities, especially in more arid regions, wastewater once treated and piped into a river and sent downstream is now captured and used for irrigation, or given advanced treatment and made part of the drinking water supply, by being discharged to a drinking water reservoir or plugged directly into the potable water system.
There are other examples of communities taking One Water seriously. The U.S Water Alliance describes such efforts at its One Water Hub (www.uswateralliance.org/one-water). Here are a few:
Green City, Clean Waters: Philadelphia. The city’s outdated stormwater system led to combined sewer overflows. In response, the city embarked on a 25-year plan using green infrastructure like green roads, rain barrels, pervious pavement and rain gardens to capture runoff on land. The goal is an 85% reduction of stormwater pollution entering waterways.
Water Hub, Emory University, Atlanta. This project recycles up to 400,000 gpd with a campus-scale water reclamation and reuse system. It uses natural plant-based treatment processes to recycle up to two-thirds of the water produced on the campus, cutting potable water usage by 40% — enabling tens of millions in projected savings over 20 years.
Adaptive management of phosphorus, Madison, Wisconsin. The Madison Metropolitan Sewerage District faces EPA requirements to cut phosphorus runoff in a 185-square-mile service area. Instead of going it alone, the district collaborates with more than 30 partners in a project where farmers, utilities, and developers all work to reduce nutrient releases and improve water quality in the Yahara River Watershed.
Aquifer replenishment, Tucson, Arizona. In its dry climate, Tucson faced depletion of the aquifers that supplied its drinking water. In response Tucson Water worked with American Rivers on a comprehensive management plan that looks at water supply holistically, with an emphasis on conservation integrating stormwater with the water supply portfolio. The city also runs an extensive reclaimed water system for irrigation and is looking to potable reuse in the future.
Basic principles
Tying, all these efforts together, the Water Alliance lists seven hallmarks of One Water:
- A mindset that all water has value
- A focus on achieving multiple benefits — economic, environmental, social
- A systems approach
- Watershed-scale thinking and action
- Right-sized solutions
- Partnerships for progress involving all sectors
- Inclusion and engagement of all
You can read the alliance’s foundation report at the One Water Hub online.
