I hadn't actually heard about the proposed regulation to subject hydraulic fracturing to the Safe Drinking Water Act. I suppose I've been too inundated with the entire horrific healthcare mess to hear much of anything else. I don't have any problems with Congresswoman DeGette's proposal - and I'm not just saying that because I voted for her.
Hydraulic fracturing is something that's actually been in use for quite some time in the United States - at this point, a little bit over fifty years. Obviously, length of use doesn't necessarily say anything about a practice's safety; there are plenty of industrial practices that have been in use for far longer that do not-nice things to the environment and to people. I mostly point this out because by now, the practice is ubiquitous in the industry. When I started working for my company* as a temp four years ago, some of the first reports I ever read detailed how formations were being fractured.
The basic one sentence explanation in the article is fair enough, but I'd like to go in to just a little more detail about the what and why. Most fluids that we're interested in getting out of rocks (water, oil, natural gas) are locked in sedimentary rocks**. We're used to thinking of rocks as very solid things; the fact of it is, many of them are surprisingly un-solid. There are two very significant properties to these sedimentary rocks that determines how hard it's going to be to extract the fluid.
The first is porosity - just how much "air space" there is in a rock. (Picture here) These spaces in the rock are basically the gaps between the grains that have been cemented together to form the rock. The higher the porosity of the rock, the more of your fluid of interest it can contain.
The second important quality is permeability - just how interconnected are the spaces in the rock? For example, a rock could potentially be quite porous, but if each of the spaces in it are completely isolated, it would be impossible for fluid to flow through the rock.
Permeability is a nice quality for a reservoir rock to have. If you want to get fluid out of that rock and it's nice and permeable, often all you really have to do is drill down into the rock and then let the pressure differential do the work for you. The fluid in the rock will be under a lot more pressure than what's in the well, so the liquid will just move on its own. But if a rock's not very permeable, that fluid flow doesn't happen easily because there just aren't many paths for the fluid to travel. Rocks like that are referred to as "tight."
Enter hydraulic fracturing. At its most basic, you just pump a lot of water and sand down in to a formation, under high pressure. The water finds zones of weakness in the formation and fractures them further; the sand keeps the fractures open. The end result is the creation of a lot more paths through which fluid can move through the formation and in to your well. However, there's also the addition of a lot of chemicals to the fracturing process, many of which are included to help keep the sand from clumping up and clogging the fractures that you've just made.
For the most part, I don't see a lot of problems with the basic practice of hydraulic fracturing. (Not on the table for discussion at the moment: the basic practice of using fossil fuels.) It aides in production - sometimes making it possible to produce from formations that would otherwise not produce at all - and ups the amount of fluid recovery. Most of the time, oil and gas producing formations are far deeper than the water table and properly done fracturing shouldn't intrude anywhere near it. That said, a lot of the time you're drilling through an aquifer to get where you need to go, or more importantly, fluid spills can occur at the surface or nasty things may find a way to escape waste pits. Even if you've got the most environmentally conscious and careful drilling company in the world, accidents can happen and should not be ignored. It doesn't take too many mistakes to harm an aquifer and potentially hurt all of the people who rely on it for their water.
In my rather inexpert opinion (and from the news articles I've read thus far) the main problem with fracturing doesn't seem to be the process in the ground, but rather spills and waste collection at the surface. Thus, I don't think banning hydraulic fracturing would necessarily solve the basic problem, which at this point appears to be surface safety, and would quite possibly have an adverse effect on the natural gas market***. If there's real, substantiated concern (which there seems to be) over contamination of ground water, then the Safe Drinking Water Act no doubt has something to say about it. Though I am also forced to wonder if adding another layer of regulation will do much good if current safe practice requirements are not being properly enforced.
Side note: There's quite the collection of links for groundwater contamination news stories at the site NoFracking.com. I used the site as a link mine to see what contamination complaints/news was out there rather than as an informational source.
* I am an intern at an oil company. My opinions are not in any way the opinions of my company.
** Some times you'll get water out of an igneous/metamorphic rock because it's seeped in to fractures from the surface, or from an underlaying sedimentary reservoir. We won't worry about that here.
*** Your mileage on this may vary, depending on how worried you are about the price of natural gas versus the possibility of finding some extremely scary chemicals in your drinking water.