Zeta (anyone else with this question),

There are a number of reasons why this is project is important and DOES NOT overlap Computing For Clean Water.

Computing For Clean Water is looking at ways to filter drinking water.

Computing for Sustainable Water is looking at the best way to prevent pollutants from getting into rivers, streams, and estuaries.

Very different goals. Let me explain why your comment about spending a few million is way off the mark....

When rain falls, some of it is uptaken by plants or evaporates, but much of it is either absorbed into the soil or runs off. Humans have vastly changed the natural water cycle, because when we build cities and pave over huge expanses of area, water can't infiltrate into the soil and usually ends up in storm sewers -- which do NOT treat the water, but rather just directly discharge it to the nearest stream or river.

In the course of flowing from rooftops to lawns to streets to storm sewers, many pollutants are collected. For example, there are chemicals that collect on our driveways, parking lots and roads, such as oil, gas, and antifreeze. There are lawn chemicals such as pesticides and fertilizers. Bacteria from pet poop (you may think this a minor thing, but several studies have shown that in some areas up to a third of the E.coli in urbanized streams comes from canine sources.). Failing septic systems and aging, ill-maintained sewer systems can likewise contribute many pollutants. Construction projects that do not use proper erosion controls can contribute huge amounts of silt to rivers.

In less urban areas, runoff from livestock can pose a problem because of manure. Likewise, rural areas also see many farm chemicals applied to crops, and some farming practices contribute to that manure or those chemicals finding their way to streams and rivers -- and then ultimately the ocean. The Dead Zone in the Gulf of Mexico is mostly due to huge amounts of nitrogen finding it's way down to the Gulf from Midwestern farms.

There are strategies to combat this -- designing sites so that the infiltrate the stormwater into the soil is the best -- the soil acts as a natural filter for these pollutants and time, bacteria and plants will break down many of them.

The menu of strategies can include things like green roofs, permeable pavement, bioswales, bioreactors, public education about stormwater, even something as simple as providing free bags to encourage people to pick up their dog poop in park.

If I understand it correctly, what Computing for Sustainable Water is doing is running simulations based on the usage of a variety of these strategies and based on future possible land uses, and seeing which combinations result in the greatest benefit for improving water quality. The project looks at the Chesapeake Bay area, but the hope is that the findings can be applied to other areas as well.

Now, some may ask "Why do we care, if it's not for drinking water? Why do I care if some stream or river has oil, lawn chemicals and dog poop in it?" Well, for one, sometimes those things are in rivers used for drinking water and add to the cost of water treatment. For another, think of people who swim in the ocean or recreate in lakes and rivers. Swimming, boating, fishing, just to name a few. All of these can lead to varying levels of human exposure to these pollutants. So there is a potential public health issue.

There are also environmental consequences. Entire river ecosystems can be wiped out by changes in their watersheds. For example, heavy siltation in a river can prevent sunlight from penetrating into the water column. That restricts plant growth which in turn restricts habitat for macroinvertebrates and fish. Some predator fish species hunt by sight and live in clear water - if the water becomes chronically cloudy, these predator fish won't thrive. And heavy siltation can cover up rocky river bottoms used by some fish for egg-laying. Changes in river and lake ecosystems can have wide repercussions.

Now, with regard to the idea the Computing for Clean Water can simply do the job in this regard, and whatever filter systems created by it can but stuck at the end of a pipe on a storm sewer and voila! we have clean rivers again, let me note the impossibility of this. In even a small city, there will likely be hundreds of storm sewer outlets. Not only that, but there are likely to be dozens of small streams and overland drainageways that lead directly to streams and rivers. For many of those, the pollutants don't come from a pipe, they are polluted by what is known as nonpoint source pollution. This could be runoff from a parking lot that flows down a hill to the stream, or runoff from a backyard, or runoff from a cattle feedlot. Not all pollution comes from a pipe, and so there is no "sticking a filter on the end of it". As Tomast noted, the Chesapeake Watershed covers thousands of square miles. Filtering a few pipes isn't going to do the trick.

Sorry for running rather long on this, but I've been involved in water quality monitoring as a volunteer for the past decade, and this is an important topic to me.

C4CW doesn't have to just be used on drinking water - you could build a filtration system that uses the technology to directly remove pollutants from large bodies of water. Depending on how large the filtering plants were and how many you made, it may take a while to remove the pollutants, but it could do the job.

Also, that's my point - all C4SW is doing is making a model. Great. That's like spending time calculating how long it'll take somebody to bleed to death when you could be actually working on healing the wound.
The only thing you listed the C4CW tech probably wouldn't be able to fix would be thermal pollution.

Don't get me wrong, making the model is useful - but not while its draining resources from the actual solution to the problem. People should wait until C4CW is done to dedicate processing power to it.

Zeta, I really don't think you understand the scale of the problem C4CW is trying to address. You're suggesting we have the capacity to filter, not just millions, but billions of gallons of water daily flowing into the Chesapeake, or that we could filter out the pollutants in the Bay faster than they are input. I genuinely think that's an impossibility, and if you scale it up to address the Mississippi River, for example, the shear scale of it becomes mind boggling.

Let's consider volumes for a second. Right now, as I type this, the James River is flowing at a rate of 6,790 cubic feet of water per second past the USGS flow gage. Translated to gallons, if my math is correct that's 52,139 gallons per second at the gage site. That's 3,128,340 gallons per minute, or 187,700,400 gallons per hour, 4,504,809,600 gallons per day. Over 4.5 billion gallons of water daily at current flow rate, and rivers don't remain static, and that's far from peak flow.

Let's ponder that 4.5 billions gallons of water daily figure a moment. New York City uses about 1 billion gallons of water daily. So that may give some scale on the filtration system that would be needed. Still think it's feasible?

If so, let's consider the following...

A week ago that James River flow was around 2.5 times that rate - almost 10.6 billion gallons of water daily. The next time a big rain rolls through the flow will spike back up again. The record flow for today's date amounted to more than 6 times today's current flow rate.

Now consider that the James is just one of half a dozen major rivers flowing into the Bay, not to mention dozens of smaller streams. Each of those major rivers is flowing more water into the Bay daily than New York City uses in a day for much of the year.

And this ignores lawrencehardin's comment about ecological impacts building such a filtration facility would entail, and they would be many.

For good order, and surely as part of avoiding confusion, the Systainable Water research moniker is *not* C4SW, but CFSW. See the official welcome post in forum: http://www.worldcommunitygrid.org/forums/wcg/viewthread_thread,32996

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Just for arguments sake:

Supposed that there is the technology to dam "all" the water running off in Chesapeake Bay, supposed it is feasible to filter all the water standard running into the Bay from major rivers, farmland runoff, and sewage. For the peak rainfall, some of the water needs to be kept "before" the dam before processing. What location would you suggest to dam off to keep all the temporary surplus water behind the dams?

For the sewage, the basements of Washington, Baltimore, Annapolis, Norfolk? Or do you want to ship this upstream again by truck-boat-plane?
For the cleaner rainfall, the streets of these cities, and the surrounding farmland?

Build a dam around Maryland and keep that as temporary lake? Or dam off some of Virginia instead? Keep in mind that you need a surface off-the-cuff of about 1/4 of the entire Chesapeake Bay on currend land surface simply to prevent the water to run into Chesapeake bay untreated.

Good luck, and be certain of a Nobel Prize if you come up with a working solution.