Q. What defines the Highlands as a region?
Gates: The Highlands is an elevated region, a topographic region that’s really a province, where you have mountains or relative mountains -- for the east coast they are mountains. It’s a long province known as the Reading Prong. There's a whole bunch of these -- the Blue Ridge Mts., the Green Mts. up in Vermont -- that are similar to these and they form sort of a spine of the Appalachians.

The Highlands region is a region of crystalline rock. Crystalline rocks are very old rocks, much older than anything else we have in the area, and they make this region that extends all the way from Connecticut down into Pennsylvania. These crystalline rocks, they were built during mountain-building events that were ancient, and they're strong against erosion, so they tend to stand high relative to the areas around them. So the topography, the woods, … everything really looks different in the Highlands compared to the lowlands in the east.

Q. Describe the terrain in the Highlands.
Gates: The Highlands topography is a rugged terrain and it includes places like the Ramapo Mountains, where you do in fact have a semi-mountainous region. Because it's high and because we are still getting the same kind of weather patterns affecting these areas, all the water that falls in the Highlands will tend to go downhill to the lowlands. So the Highlands has an influence in all the water areas around it both in New York and in New Jersey.

Q. How does crystalline rock impact water supply?
Gates: Crystalline rock means that it was cooked up at great pressures and temperatures deep underground. These are mostly metamorphic rocks, also igneous rocks. They have no natural permeability to begin with. The only way then you can put water into these systems is by a process of cracking them, or fracturing them, or faulting them. Then you get these cracks that open up in the rock. The water has to go through cracks.

Q. Water then travels quickly through crystalline rock?
Gates: Water will pick certain fractures in crystalline rock and will flow along certain fracture plains, and you sometimes get water pouring out of certain cracks as opposed to others. Then you can actually see it pouring out on outcrop faces or on sides of roads and that shows you how groundwater is moving through those crystalline rocks. Another example: in winter, you’ll see huge icicles emanating from a fracture in a tall rock wall along a highway in the Highlands. That’s water that has traveled through the rock.

Q. How is that different from other parts of the state?
Gates: The whole of southern New Jersey that we call the Atlantic coastal plane is all relatively unconsolidated material, and even the Newark basin, they’re all composed of sedimentary rocks. And in sedimentary rocks you have a bunch of grains that are all stuck together, and the water is forced to wind its way around each one of these grains as it filters down into the soil. By winding around grains like that it makes a lot of surface contact with the grains.

So, in southern New Jersey and in the Newark basin, a lot of these are sedimentary rocks and sedimentary rocks are very good at filtering water. Again, what happens is you have a bunch of grains, sand grains or cobbles. They are touching each other. When the water filters down from above on the surface, it will have to wind itself around each one of these grains, and by winding around the grain the water makes a lot of surface contact. That contact can drive chemical reactions which occur all along the grain. And by that method a lot of the pollutants can be removed by reacting with the surface of grains. In addition because the grains are touching each other, you get these narrow necks between the grains. Things like bacteria get caught in the narrow necks and so this filters the bacteria in addition to the chemical filtration that takes place in these rocks.

Now in the Highlands, in crystalline rocks, the problem is now you're dealing with cracks. Instead of having the winding effect, you now have a crack that the water can flow straight down through. As it flows through it makes minimal contact with the grains around it. Basically it’s like flowing through a pipe. The water doesn’t receive the chemical effects, and because the cracks are sometimes rather large the water passes through carrying the bacteria with it.

Q. So the Highlands geology isn’t helping to clean the water?
Gates: Again, most of New Jersey is made up of sedimentary rocks. Sedimentary rocks are composed of grains that are stuck together. Water needs to wind around these grains, and so chemical reactions remove some of the pollutants from the water. In addition, the narrow necks between the grains physically filter bacteria and that cleans up the water too. In contrast, in crystalline rock there’s no natural permeability. The grains are stuck right together. You have to have cracks or fractures in order to transmit the water. Well, the crack is like an open pipe. The water just goes straight through, and it doesn’t make any contact for the chemical reactions, and the rocks are not close enough together to get rid of the bacteria.

Q. Then why has the Highlands historically been such a dependable water source?
Gates: In the woods you have a lot of decaying plant matter and things like that that are on the surface. When the water flows over that, that layer of decaying matter acts like activating charcoal essentially. That matter can pull pollutants out of the water and filter it down so that before it gets into the bedrock, into this fracture system, it gets relatively cleaned up. Otherwise if it went straight into the fracture system where we didn’t have that cover, and we had a lot of houses putting out a lot of pollutants, then water quality would be worse than in the Highlands then in the lowlands.

Another reason that we use Highlands water so much is that there are fewer houses, there is less development, than there are in the lowlands. We have bigger areas of forest which, on the surface, can filter down the water and clean it up. Again, if we didn’t have those large stretches of forest we would probably have worse water quality than the lowlands.

Q. Is the water supply a vulnerable system?
Gates: Absolutely. It's absolutely a vulnerable region. Anytime they have a spill up in the Highlands, a leaky gas tank, a leaky landfill, something like that, it radically impacts the water. And there's been a couple of cases where when you have those spills, you really destroy the quality of the water in the local area.

Q. Does that have an impact outside the Highlands?
Gates: I ask my introductory classes which way water runs, and there's one answer, … down! So water always flows downhill. Therefore when you have these regions with relatively steep slopes and the high elevation, a lot of the water that falls in the Highlands eventually comes down into the lowlands, whether it be from surface water or groundwater. Because the slopes are relatively steep, the water is actually injected down into the systems around it. Therefore the groundwater systems and the surface water systems on all sides of the Highlands are directly and very significantly affected by the quality of water that comes from the Highlands.

Q. What are some of the geological highlights of the Highlands?
Gates: The Highlands are ancient mountains. They represent just the remnants of some huge mountain system that was bigger then the Himalayas at one point – perhaps longer than, and at least as high. So we’re talking about huge mountains! We’re looking at the roots of them now. And there are still some places left in the Highlands where you can see how intense that deformation is.

Those intense forces can still be seen in some of the rocks of the Highlands. For example, there’s an outcrop on Route 23 northbound that shows the folding of layers. These were layers that were laid down flat originally about 400 million years ago and then later, during a continental collision, the collision folded up the rocks. So the multi-colored folds that we see in the outcrop on Route 23 are the result of that squeezing that took place when the two continents hit each other and folded the rocks up because of that pressure.

One can see the stresses that were put on those rocks in order to build them up into this Highlands, this mountain range that still exists today -- which is amazing because this was pulled apart probably 250 million years ago, and the mountains are still sitting there!

Q. What helped create the Highlands geology?
Gates: New Jersey sits in a great spot geologically. The end of the glaciers went through Newark and out through Morristown and up across New Jersey. At the point where the glacier came down you have a mile thick sheet of ice that just scraped clean all the tops of the hills. So, you go out into the hills and you see these pavement surfaces of rock where the glacier has come down and pulled all the soil. As the glacier retreated, it was melting, and this would wash the soil back out of the glacier as it retreated. This would then dump the soil and sediment into the valleys in between those high spots. So now in the Highlands you have a system where the high spots are scraped clean, but out in the valleys you have relatively thick fill of glacier sediment. When we talk about water supply in the Highlands, there is a very complicated, double aquifer system.

Q. How did European colonization impact the Highlands?
Gates: The whole Highlands region was developed for its geology. It was developed because it had iron deposits. All the way back from colonial times people went around and found these iron deposits and started mining in them. And there are literally hundreds of mines in the Highlands regions where they removed magnetite. It was largest source of iron in the continental United States, from the Revolution all the way up through the Civil War, that's where most of the iron came up from, for the United States. So the region became a warren of these mine systems, so they could be able to extract this magnetite ore. The problem is, in those days we didn't have an EPA to govern what we were going to do, therefore everything turned into an absolute mess. There were no trees. There were no animals. There was nothing up there at the time. There were polluted lakes, and there was polluted air. It was a mess.

Q. Why was mining so detrimental to the landscape?
Gates: Normally when you do iron mining, you need a source of ore, a flux – to process ore into usable substance -- and you need a fuel, to create and keep the furnace burning. And we have the flux and ore up in the Highlands, but we have no fuel, no coal like they have in Pittsburgh. That’s why places like Pittsburgh have iron mines. So, what they had to do was charcoal down all the trees. They cut down all the trees and made these big charcoal pits all over the place. So not only did you have all the pollution from the mines, but there was a heavy smog hanging over the area because of all the charcoaling that took place all the time, and all the trees were stripped down. The air quality was terrible. Not only did you have this smog up in the air, but they were smelting the iron at the same time. Most of it's pretty clean, but some other stuff is not clean and so you could have sulfur fumes going up and coming out of the smelters, in addition to all the charcoaling and the lack of trees. So it was a mess.

Q. Did that have long-term effects?
Gates: For example, there were no animals there. They’d destroyed all the habitat and there were no animals left. I saw a newspaper from the late 1800s, and in a front page they cited that locals had seen eight deer up in the Highlands, and that was big news. These days you can't go anywhere without seeing deer, and yet they had no deer left at that point. They ended up bringing in most of the animals. Eventually they had to repopulate the areas because the they had completely stripped them out.

Mine tailings are everywhere throughout the Highlands. Unlike weathered rocks that have been chemically broken down over the years, these tailings are fresh rock surfaces with all kinds of strange elements in them that you probably don't want sitting up in your systems -- things like sulfur, lead -- things like that. People love to blast in the Highlands because there’s too much rock, and you want the landscape nice and low. And that's all fresh rock surface, and all the old mining tailings will chemically react to degrade your water supply. So there's a big problem with tailings. Other problems are the mines themselves. We hear once in awhile about a mine collapse. You think the rock is pretty solid under your feet, but if there's a mine underneath it and over the years you get frost wedging and a little erosion, the mines can collapse.

Q. Why did mining in the Highlands decline?
Gates: Just around the turn of the century a major discovery was made out in Minnesota that rendered this whole area less attractive, economically. So everything was abandoned pretty much between then and 1910. People just left the mines, or people would sell them, or they were just donated to the state and that's where some of the big state parks came from. So many large areas have been restored through WPA projects. In other places it's just done it naturally, it's recovered on its own, and a lot of those naturally recovered places show a lot of evidence of some of the prior conditions.

Q. Can we continue to depend on the Highlands for water?
Gates: The water is really mediocre in the Highlands. And because it doesn't have that filtering capacity, anything you do up there is going to hurt the water supply, and therefore it's very environmentally sensitive, much more so then things down in the low lands. The only reason we use it is because there aren’t many people up there. The lack of population, the lack of overflowing cesspools and lack of industry, things that would negatively affect the water -- that's the only reason we can use the water as is. If we put in more industry or too many more people, it will completely destroy the water supply.

Historically, the Highlands were too far to commute. You didn’t develop big housing areas out in the Highlands and so therefore, because it was left pretty much pristine, you could rely on it for water supplies. And if you put more people up there, it's probably more sensitive than the lowlands are, and that's why we have to be very careful as we develop areas up in the Highlands.

Q. Are the Highlands at a turning point?
Gates: Absolutely. As the population centers are moving out and getting closer and closer to the Highlands, all of the sudden that area that is naturally recovered over the years is now under pressure. Where you start putting housing developments in, especially in places where you have to have local sewer systems, it's really going to affect that place all over again. And you’re in great danger of nutrification of lakes. When you put things on your lawn to make it grow better, or you have a septic tank that maybe overflows once in awhile, all of a sudden you put in these very heavy nutrient-laden waters that filter down back into the lake. Then you get things that take over the lake. Then you have to go in and chemically remove the algae and things like that and then all of a sudden you end up with this chemical imbalance in the lakes. They were all nutrified in general anyway, but you put some new houses in there, and you're really going to cause some damage to the lakes and reservoirs.

Also, a lot of things can make it down to a lake that normally you wouldn't expect to, but because of that removal of the natural forest cover which does some filtering and putting in a house or something industrialized, the polluted water can get all the way into the lakes from quite a distance away. Lakes can be affected from much farther out from when you remove the forest cover.

Q. Do you have any personal connection to the Highlands?
Gates: When I was a kid growing up in Rockland County, New York, I used to go hiking in the Highlands and think I gotta get a job where I go out and do this as a living, and now that's what I get to do. I’ve certainly had an interest in the Highlands all the way back to my teenage days and it's just grown stronger as I've gotten to work there as a professional. When we went in there, strangely enough, some places in the Highlands had been mapped out, but there hadn't been many studies, considering how close it is to New York City. You'd figure there would have been a lot of research, but there really wasn't. So I went off and did a lot of mapping, and we have done all kinds of things from dating the rock, finding out different ages of rocks, and we've come up with a lot of new things, in addition to putting together a whole geological history with faulting, and the movement of rocks in the area that wasn't known about before.

Q. Is the Highlands nationally significant?
Gates: Well, I would say so, but of course I'm biased. It's a nationally significant region in that it is a big water supplier and sits in one of the most densely populated areas in the US. Therefore protecting it is of great importance, because we are going to be relying more and more on the resources of those Highlands to be able to facilitate this population growth in New Jersey and New York. In addition it provides us with the only place to have a kind of natural area that’s so close to the northeast US, which is so urban. This allows people to go out and actually see what the natural environment is like. Some of the issues that people wouldn’t have access to, they can really get the hands-on understanding out there, so this is also an educational issue and a quality of life issue.