WASH 101: “Sourcing” Solutions

January 3, 2019

Posted by Amanda, Development Director

At 20 Liters, we believe that before you can solve a problem, you need to understand that problem. So, if you’re just joining our WASH 101 conversation, I would encourage you to start back at WASH 101: W is for Water to catch up with us.

As a quick recap, we’ve already talked about each part of the WASH acronym [WAter, Sanitation, Hygiene]. We made sure we understand the shared language of the WASH sector and we’ve touched on some of the disparities that are masked by global statistics.

So now the part I know that I have been waiting for… SOLUTIONS to the global water crisis! And, spoiler alert, drilling wells isn’t the only one.

Now, we’re going to take our time and break down each different category of solutions – where they work, why they work, and why they fail in some places. These conversations may get a little technical in the science, technology, engineering, math direction… so I’ve asked 20 Liters Managing Director, Chip Kragt to be our guide as we delve deeper. So here we go…

People who work in the WASH sector are painfully aware that there’s no “silver bullet” to providing access to clean drinking water. Determining what solutions could work well based upon the local variables is often a complicated and long-term undertaking for any water project. A helpful way to begin unraveling this complex environment is to divide all the available solutions into some broad categories. Each one has their strengths and weaknesses, which our next several posts will cover in more detail. But for a high-level overview, we can split them into 5 groups:

  • Physical Intervention: including filtration, adsorption, sedimentation, boiling and distillation
  • Biological Intervention: including slow-sand, activated carbon, antimicrobial metals
  • Chemical Alteration: including chlorination, flocculation and iodination
  • Electromagnetic Radiation: including UV Light treatment
  • Sourcing: including rainfall, groundwater, underground aquifers, springs, and human-intervened (bottled, wells or municipal water).

[This is Amanda, because I can’t help but jump in. Honestly, there are words up there that I don’t fully understand. What does “adsorption” mean in the context of water purification? Feel free to Google things that we haven’t explained yet, but I promise you that we will get to definitions for all of these terms in future posts as we break down each type of intervention.]

While most of these categories deal with how to address various contaminants in water, one of these categories is distinctly different. So, let’s start by addressing the single-most critical question that can help us determine the water’s current state: Where did the water come from?

Some people don’t consider Sourcing to be a category, but when attempting to provide clean water, sometimes the source is the solution. If the issue is that people are drinking biologically-contaminated ground water then helping people switch to a different water source can (might) fix the problem.

Sourcing can also get a bit murky (pun intended) because “sourcing” can easily overlap with other categories. For example, rainfall water was recently evaporated (distillation: one of the physical interventions). Water from underground aquifers tapped by wells or springs usually passes through multiple layers of sand and clay before reaching the aquifer (sedimentation, adsorption, filtration).

Sourcing also suggests what contamination has probably occurred. An aquifer is not necessarily sterile or potable, so wells might just pump dirty water. An unprotected spring could be exposed to animal feces and plant materials that encourage bacterial growth. Municipal water sources, as we’ve recently seen here in Michigan, can accidentally add dangerous elements due to mistakes, neglect and aging infrastructure.

[Amanda again with a super non-technical recap: Where water comes from matters, but the source of water may also be the source of the problem. If you get your water from a clean source, your water will be clean. If you get your water from a source that isn’t properly managed, your water may be dirty and require additional “solutions” to make it safe to drink. Make sense? Good.

Now we’re going to talk more specifically about a couple of common solutions that rely on “Sourcing” to provide clean water.]

When most people think about solutions to the global water crisis, they think about one main idea: drilling wells. Since wells are one of the primary Sourcing solutions, let’s spend a bit of time on them.

A borehole well (as opposed to the type that Lassie helped save Timmy from) is still a very popular solution, even though the average borehole well in the developing world costs around $5,000, breaks within 3 years, and is never repaired. The problem is so bad that there are WASH agencies (like our friends at Water for Good) that have dedicated themselves to just repairing existing wells and helping create the maintenance and repair infrastructure to keep those wells working.

I’m not suggesting we should stop drilling wells altogether. If surface water isn’t available, your only option might be to look for it underground. I do, however, get pretty frustrated when I’m in Rwanda, crossing the Nyabarongo river and see a broken hand-pump well about 30 feet from the riverbank.

There are other problems with wells (beyond the price tag and lifespan). Wells aren’t always clean. The underground aquifer could be contaminated with E. coli and a host of other biological dangers. Wells also aren’t always preferred. Ironically, that broken well next to the Nyabarongo river was hardly ever used even when it did work. Local leaders complained that the water contained high quantities of silica (sand) which made the water gritty and still in need of further filtration.

Since 20 Liters focuses primarily on filtration, it’s easy for us to only highlight the negatives of wells, but let’s fix that now and talk benefits. Wells are typically high-volume and fast flow so you can serve a few thousand people at a time. A properly built and maintained well that taps a clean aquifer can provide very clean water. Those of us who live in rural areas, away from municipal water supplies, rely on this fact every day.

If there is an ongoing system and network for maintenance and cost management, like the establishment of an oversight committee, a well can be cost effective in the long-term. Wells also create community cohesion because the well is a shared communal resource. Wells also become access points for other interventions like adding a hand-washing or container disinfecting station.

[Amanda on her soapbox: Wells are a really important part of providing clean water. They can work well and they do work well in a wide variety of settings. I am not anti-well. But. I do believe it is vitally important that we expect more of organizations that are digging wells. It is not okay for us to dig a well and then leave it to break down or not maintain it in a way that ensures that the water coming from the well continues to be a safe source of water for the community. #sustainablesolutions]

One of the other most commonly used “sourcing” based solution – protected springs, share almost all the same strengths and weaknesses of wells. The biggest difference is that protected springs are operationally simpler (the water is being pushed up by underground pressures instead of being drawn up by mechanical means) and so they are less likely to need costly repairs.

Our favorite sourcing solution at 20 Liters is rainwater harvesting. By capturing the rain, we reap the benefit of collecting water at one of the cleanest phases of the water cycle: condensation. Plus, unlike collecting water vapor, gravity does all the mechanical work for us, we just need to catch it. And, we can further benefit from existing systems: the roofs of large buildings. To catch rainwater, all you need is a large surface that slopes to a common point. So, we set a 5,000- or 10,000-liter tank next to a church, hang some gutters, run a bit of pipe and we’re done. A good 5-minute downpour is enough to fill most of our systems. Coupled with Rwanda’s 2 rainy seasons, these systems provide much cleaner water for a significant portion of the year. We use churches because they usually have large roofs and are built in the center of communities, whereas the river or swamp has a tendency to be farther away, so this also shortens the walk for water, giving people more time for education, employment, and rest.

The ideal rainwater harvesting systems also include some “first flush” capabilities. In between rainfalls, roofs tend to collect dust and debris (like bird poop). This undesirable stuff rinses off with the first few liters of water, so if you can catch the first “flush” of water, you can keep debris and contaminants from entering your tank. Keeping sunlight away from the water in the tank inhibits algae and bacteria from growing.

[There are tons more sourcing-based solutions that we could talk about. But hopefully these couple of solutions give you a broad overview of what we can accomplish with sourcing and what can’t be accomplished with sourcing. If you have a specific question about another sourcing-based solution, email us at info@20liters.org and we’ll talk about it.]

In future posts, we’ll examine the other categories and talk about ideal uses and situations, but the best place to start is knowing the water you have and where it came from.


If you want to read more about sourcing, start with these links and just keep clicking:

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