Ditch or Pipeline? Neither is likely to help our water situation.

As parts of the country endure flooding while other regions continue to suffer from a history-making drought and water shortage, it’s logical to wonder why we can’t figure out a way to move some of that water from one area to the other. Associated Press Science writer Seth Borenstein writes that the idea is simply not feasible, either economically or politically. The article is a good high-level survey of some of the arguments against this redistribution scheme, but it’s a bit short on specifics.

The politics and legal issues of the situation are possibly insurmountable, but the cost of building infrastructure that could transport enough water to make a difference is just mind-boggling.

I’ve not seen a cost estimate for a massive water transport project, but with a little back-of-the-envelope calculating, it’s possible to create an order-of-magnitude guess by using another massive and well-known project as a comparison: The Trans-Alaska Pipeline (TAPS), completed in 1977 to move crude oil from the North Slope of Alaska to Port Valdez in south Alaska.

TAPS consists of a 48″ pipeline stretching for 800 miles. It cost about $8 billion in 1977 dollars, and has a capacity of around 2, 000,000 barrels per day (equivalent to 84 million gallons per day). The crude oil that the pipeline transports weighs about 7.4 pounds per gallon.

Using these facts and some additional assumptions, we can paint a very primitive picture of what it would entail to build a similar pipeline to transport water.  Let’s assume that we want to grab water from the mighty Mississippi River and move it to Lake O.H. Ivie in west central Texas, a major source of water for Midland. We’ll use Vicksburg, Mississippi as the assumed origin of the pipeline, since it’s roughly at the same latitude as the end point.

It’s about 600 miles from Vicksburg to the lake. All things being equal, the cost of the pipeline would be $22.5 billion, based on the inflation-adjusted cost of TAPS ($30 billion for 800 miles). You could rightly argue that the rough Alaskan terrain inflated the TAPS cost  considerably; drastic elevation changes required expensive pump stations, and other factors such as weather, water crossings, environmental safeguards, etc. drove up the cost.

However, the TAPS project had one huge advantage that our
MS-to-TX project wouldn’t have: less than 10% of the land crossed by the pipeline was privately owned; the rest is state- or federal-government owned. While I have no doubt some rather intense negotiations went on to get easements across those lands, it must have been a cakewalk compared to getting easements from potentially hundreds or thousands of landowners between Texas and Mississippi.

There are a couple of additional considerations to complicate things. Water is heavier than crude oil (at least the crude produced from the North Slope of Alaska). Pumps have to be bigger to move the increased weight. (Also, scientists created a substance that was mixed in with the oil to make it slide more easily through the pipeline ­- known in the trade as “slickum” – that reduced the required pumping capacity, but I’m pretty sure you wouldn’t want it mixed in with your drinking water.)

While 84 million gallons per day sounds like a lot of water, it’s still only enough to meet the daily demands of four cities the size of Midland (based on our current 22 million gallons per day usage). And we haven’t even considered the cost to operate and maintain the pipeline.

So, if a pipeline doesn’t provide the necessary capacity, what about digging a big ditch? Canal systems have been used for centuries to distribute water.  I have no idea what it might cost to dig a canal from Mississippi to Texas, but the logistical issues are probably many times more complicated (it’s comparatively easy to run a pipeline under an interstate, for example). Then there’s the issue of elevation change. Vicksburg is essentially at sea level; O.H. Ivie is about 1,500′ higher. With few exceptions, water runs downhill, and you have to convince it to do otherwise. I’m sure there are some engineers in the audience who can compute the horsepower needed for pumps that will move a few hundred million gallons of water per day uphill. I can’t, but I’m guessing it’s a bunch (sorry to have to use such technical terminology).

Having said all of this, I suspect that if we were starting with a blank slate today, we’d conclude that our current interstate highway system could not be built, due to imposing economic and political roadblocks (pun intended). A national water distribution system is achievable, but I doubt we have the national resolve to make it happen.