Land, Life, and Environmental Change in the Himalaya
Let me welcome all of you here. We're very glad you could come to the first lecture for this year's class of the Jefferson Science Fellows. My name is Bill Colglazier, sort of the new science and technology adviser at State, but one of the real pleasures of my office is that it is sort of the stewardship of the Jefferson Science Fellows, a program that was created actually by one of the predecessors in this office. The fellows program is now in eighth cohort. It brings distinguished scientists, tenured faculty from universities to come and spend a year here working in the State Department, and then being available for four or five years after that as a consultant.
When I started my job in the summer I met with all of the fellows who were here last year individually and was tremendously impressed, both by what they learned about the State Department and foreign policy, but also what they contributed during their year here, and the class this year is equally distinguished and impressive. There are 13 Jefferson Fellows this year, there are eight at State and there are five at USAID. As I said, this is the -- we're trying to have -- try to have all of the fellows, give them an opportunity to give a lecture while they're here, either at State or USAID and this lecture series is sponsored both by the science adviser's office and OES, and of course with USAID.
Well, it's my pleasure to introduce Dick Marston, who's the first lecturer. He is a distinguished professor of geography at Kansas State. He's been head of the department. It's also interesting to know that he is a certified professional hydrologist, so he combines both geography and hydrology. He's spending his year at State working in the Office of the Geographer and INR and a number of fellows in the past have had a great time working in the Office of the Geographer. His special expertise is geomorphology, the study of land forms, mountain geography, water resource geography. He's done studies in a wide range of countries, France, Brazil, Mexico, the Himalayas of Nepal, India and Pakistan and the American West of the Great Plains. He has also done field research on the Juneau ice field in southeast Alaska. He's particularly interested in the changes that occur both from humans as well as the natural changes in mountain regions. I think the -- his lecture today is on a fascinating subject, on environmental change in the Himalayas, so I won't waste anymore time but ask Dick to come up here and we look forward to his talk.
Dr. Dick Marston:
Thanks Bill for the nice introduction and thank you everybody for showing up this morning. I’m pleased to discuss a topic that has been of interest to me for a number of decades now, looking at this incredibly fascinating chain of mountains, 2,400 kilometers long and the Himalayas that separates the Tibetan plateau from the lowlands of India and Bangladesh and south central Asia, and this is an area that has been steeped in regional conflict for a long time, hasn't it? I don't have to tell that to anybody here in the room, but you might want to read sometime a book called “War At the Top of the World” which chronicles the centuries of conflict between countries in this area, or you might want to look at the most recent copy of the Economist, which came out recently. It has an article about the growing rivalry between India, China and Pakistan over the management of rivers and in specific, they're looking at the Baghilar dam in India controlled Kashmir and what that might mean for Pakistan, so we could talk about Kashmir for an hour, very easily, we're not. We could talk about the Siachen glacier, how India and Pakistan have troops lined up on both sides of the glacier, lobbing artillery back and forth. We're not going to talk about that, instead we're going to talk about geo-hazards and other types of water resources conflicts.
The first area we'll talk about is Nanga Parbat, on the western end of the Himalaya chain of Pakistan, the ninth highest mountain in the world and that will involve research that was funded by the Continental Dynamics program of the National Science Foundation. Then we'll look at the Garhwal Himalaya in India, again some research funded by the National Science Foundation, in that case by the international office, and finally we'll end up by looking at central Nepal, the Manaslu-Ganesh and Langtang Helambu area, and that was work funded by the Foundation for Glacier and Environmental Research, but first a disclaimer. I want to make sure everybody realizes that I'll be discussing past research that was done long before ever I joined the U.S. Department of State in August, and none of the views I represent here today are to be construed as the positions for the U.S. Department of State.
We're going to talk about two major themes. This is the story of two major themes in this part of the world. They play out in other areas too, but we'll talk about south Central Asia. The first is the need to separate environmental change due to human activities from change that would have occurred without human interference. I just think if we can't do this as scientists, we risk the possibility that we're going to blame people and societies for change that they have nothing to do with and maybe enact policies that cause more harm than good, or conversely, we may ignore the effects of humans when really some corrective action would be well deserved. So this is an important challenge, a very difficult one that we face, not just as geographers, but all of natural science, and the second theme we'll discuss today is really one that does deal with the power of geography. Place matters in the Himalayas, whether you're talking about differences between the western Himalaya and the eastern Himalaya or differences due to elevation. We could be talking about glaciers today, we'll say very little about that, that would be a worthwhile topic too, but certainly the response of the environment to human activities or natural change does vary depending on where you are located.
So a little bit first on some background information about the Himalayas, you remember that what we have here is the Indian plate on the left colliding with the Asian plate, roughly 60 million years ago, creating a shortening of the crust by about 300 kilometers. That shortening was accommodated by uplift and most of that uplift occurred along major thrust vaults, which are shown in this cartoon and I want to call your attention in particular to the main central thrust, this one right here, because most of the work I'll discuss is in that vicinity, and that's where most of the uplift occurred, even though you have higher elevations further to the north. So we look at a more detailed geologic diagram of the area and here again, with more vertical exaggeration, is the main central thrust and I just wanted to point out that not only the topography but the underlying geology differs quite a bit. We have the higher grade, more resistant metamorphic rocks at higher elevation than we find below the main central thrust, we find lower grade metamorphic rocks. This is the reversed metamorphism that the Himalayas are so famous for, and you can tell when you’re walking back and forth across the main central thrust, it's not just one fault, by the way, it's actually a series, but there are certain minerals that are just lying there on the ground surface, these beautiful platey, light blue minerals known as kyanite, are readily apparent on the ground to mark your location, but a lot of what I'll talk about in terms of how place matters concerns where you are relative to the main central thrust, and just as a clue to upcoming attractions, I'll show you this one GIS map that was created to look at slope failures in the Garhwal Himalaya.
This happens to be the Alaknanda River valley. There's the river, and just around the corner up here would be the source of the Ganges River, the Gangotri glacier, but if you look at the distribution of mass movement, you see it's not random in this location. In fact, you see a lot right along the river, the red areas would be areas susceptible to slope failures, landslides of one sort or another, because of rivers that are down cutting and undercutting the toes of slopes, but you also see a linear pattern and a linear pattern here, perpendicular to the river. Guess what? Those are surface expressions of the main central thrust. Pointing to the importance of geologic faults and earthquake action, triggering earthquakes in this area, more so than the impact of land use and land cover changes by humans. Unless you don't believe that story, take a look at this Landsat view.
You'll remember the earthquake in Pakistan, October 2005 that killed something like 75,000 people and on a Landsat satellite image, you can see the impact of this earthquake, here's the epicenter. Green would be growing vegetation and look what happened in this about 15 miles radius of the epicenter. The lack of vegetation there is because of all the mass movement, landslides of various ways, shapes and forms that were created -- we flew over that area in an airplane, also drove through the area and the devastation right after that earthquake was really quite remarkable and reminded us of the degree to which slope failures do depend on seismic action, and this, by the way, is the Karakoram highway, which we followed up to our field area, around Nanga Parbat, which is just off the top right of that slide. I'll show you a few more views, dealing with slope failures, just to give you a general impression of how unstable the region is. Here's a giant block failure that slid off this mountain. It blocked the Alaknanda river, a major river, and it created a dam behind the landslide. Here you see a bridge that was washed out and some of the sediments that were deposited behind that dam. The Indian army came in and used explosives to create a new path for the river. Unfortunately they used too much in the way of explosives, it created a devastating flood downstream that killed eight people and ruined some valuable farmland low against the river.
When we were out there in the field, our path -- this is the main road going up the Alaknanda River valley, as you approach the Gangotri glacier and it was blocked by a landslide occurred one day, and here is a major landslide that occurred on one of the major pilgrimage routes in the Indian Himalaya backing up no fewer than 20,000 people, none of whom turned around, they were all headed to one of the five pilgrimages sites -- pilgrimage sites in the Indian Himalaya. They waited for the Pakistani -- or sorry, the Indian army to repair the road, which they did over a weekend and they were allowed to continue. As if that isn't enough to worry about, one of the biggest problems, I think, that will be even more exacerbated here in the future, deals with glacial lake outburst floods. As glaciers recede, they leave a lake between the ice and the terminal moraine, and these now number in the hundreds and some, perhaps 20 or 30 in Nepal alone are considered quite dangerous and they're worth monitoring. Here, in fact, is the site of what was going to be a $500 million dam to be funded by the Canadian international development agency, and you see the site, construction roads have been put into place and the construction was just about to start right here at the dam site. Then a glacial lake outburst flood occurred upstream, this is along the Arun River and had that dam been in place, this is what it looked like after the flood, it certainly would have filled up with sediment and very likely would have breached the dam. The Canadian international development agency had never done a survey of the potential for glacial lake outburst floods upstream of this dam site.
Well, you have lots of water, lots of sediment moving down these streams, across the Himalaya and you might think that any dam you built would be a bad mistake, but take a look at this one. This is the Trishuli Hydro Power Project near the village of Trishuli in central Nepal along the Trishuli River and you might think, what happened here, did they run out of money? The dam's only built halfway across the river. This is a project that the Indian government built in Nepal so they could export electricity during the peak of the monsoon season. Even having a dam only halfway across the river during a monsoon peak runoff period, it'll back up the water high enough that you can power six different turbines. At the low flow time of the year, what's done is to divert out of the water upstream, run it down a canal and then let that pass through the six turbines, so it does generate a total of -- well, a capacity of 2,400 kilowatt hours at any one period of time. Now, why would they do this? Well, during the low flow period of the year, they'll take the sediment, the bed load that backs up behind the dam and just bulldoze it out into the main channel where the river can carry it down and in the following years, monsoon floods. So this is kind of a creative, innovative way to deal with a big sediment loads in the Himalayan rivers.
So now let's take a look at Nanga Parbat and our efforts to understand better the rates of uplift and erosional processes over longer periods of time in Himalaya. Here located at a place called Fairy Meadows with my son Bryce and we're looking at the Raikot glacier face of the Nanga Parbat and I wonder if anybody has an idea how much relief in thousands of feet occur from the base right here up to the peak right there? Any one want to hazard a guess, how many thousands of feet that might be? I just want to give you an idea of the scale.
Somebody said 14, that's correct. Yeah, 14,000 feet and you don't see an awful lot of foothills in the intervening time.
So I remember one morning waking up, yeah, waking up and watching an avalanche, which took about five minutes to come down from the peak to the base, which is by chance where we were going to be hiking to that morning. So, it's a dynamic location and we had a grant from the National Science Foundation, a grant led by Peter Zeitler and -- at Lehigh University and a cast of thousands, but our part was to figure out all the rates of erosion, be they from glaciers, wind, and river -- fluvial processes and this is just a schematic showing how we were putting together a sediment budget for the region. Why? At about 20,000 feet above sea level, we find rocks -- granite, a rock that's usually formed deep in the earth's crust. It's up at 20,000 feet elevation and it's only a million years old. How can this happen -- and so this area has experienced unbelievable rates of uplift and we're trying to figure out if it's the either tectonic or erosional removal of rocks off the surface of the Nanga Parbat Haramosh Massif that's allowed the mountain to be uplifted and that would take incredible rates of erosion to produce that kind of effect and we found out it in fact could happen.
So, take a look at this graph. Here's a graph showing how the rate of denudation, the rate that the landscape is lowered, varies as a function of elevation. Of course, many other factors affect the rate of denudation, that's why you see so much scatter here, but there's a general trend. I just wanted to show where our data, from Nanga Parbat and our latter data I’m going to show you from the Garhwal Himalaya plot on this diagram, we were measuring what turned out to be the highest rates of denudation, erosion, ever measured on the surface of the earth and in the case of the Garhwal Himalaya, that was an area that was supposed to be tectonically inactive and rivers were not supposed to be downcutting for the last 20 million years, so it just goes to show you one of the lessons of today's talk is rather than just believe what you read in the literature, you have to go out and do muddy boots geography, go out and measure these things yourself, now that we have more sophisticated techniques of measuring rates of uplift and denudation. So speaking of the Garhwal Himalaya, my colleague Liz Catlos who's now at the University of Texas, and I went down for two summers to the Garhwal Himalaya and she was in charge of measuring rates of uplift using a technique known as monazite geochronology. She found, again, in this area that was supposed to be inactive, she found that there was been significant movement of -- along faults at about one and four million years ago. By the way, she named one of these faults after the program officer at NSF that funded our grant. We thought that was a good move.
My part of the project was to figure out the rates of river incision. So we were using cosmogenic radionuclide dating techniques and this is the kind of landscape, viewed in this photograph, that we were working in. So one of the things we did was to just produce profiles of glacial valleys and you can see when you look at this, this is just one of the many we looked at, this post glacial notching. Since glaciation ended in this area, rivers have been down cutting very fast. Well, that's not essentially, you know remarkable news, but in an area where you have rapid uplift and rapid river incision at the same time, this is the kind of topography you get. Convex slopes and river notching. You can see right about there is a break in slope and there's been an inner gorge created, this is something pretty common in the Alaknanda River valley. The Alaknanda River is down cutting so fast that tributaries come into it but they have a nick point right here. This river is down cutting, leaving behind this higher tributary that's coming in. Again, here's just another example of a river gorge. So he measured the rates that these rivers are downcutting. Remarkable rates.
That's all by way of background to get into the main story here about Nepal and before we talk about Nepal I want you to think about Bangladesh downstream the Ganges River system, where you have people living at very low elevations, just a few meters above sea level and in high densities, you know, up to 2,000 or even more people per square mile, and these are areas that have been susceptible to devastating floods in the past. You see some of the statistics there. Well, Bangladesh has blamed Nepal and specifically the subsistence farmers in the Himalayas for contributing to accelerated run off and the problems that deal with flooding and channel shifting in Bangladesh. So when you walk through this area of the Himalayas, you see that monsoon flooding does have definite effects. Here, for instance, is the main east-west trail through the middle mountains of Nepal. You don't see a big footbridge, you see logs and this is at the low flow time of the year, right about now, in November, later November and here's one of our sherpas crossing, we all to cross on this, but you look at these rocks you don't see an awful lot of aquatic vegetation, you've heard the expression a rolling stone gathers no moss. These big boulders are rolling every year during the monsoon floods and you might have water up here for three or four months at a time, at which time these villages are cut off, one from another. The water and sediment proceeds downstream where if you're in a lower caste, you're going to be also on a lower river terrace and you see what happens to agricultural fields every year. Really, during the monsoon floods, even though the rock walls that divide property are still there, you know, this crop has been taken out and yet, the people that own that property will go in and repair it. They'll clear off the sediment and try to get out one or two crops of rice, whereas if you're up here on a natural river terrace, you're pretty well protected.
The other thing that you notice when you walk through the middle mountains of central Nepal is the pervasive mass movement. So you can see this big deep slope failure here in the background, very common. You see shallow landslides like this one and I wanted you to notice that this case -- in this case what happened is the slide came down and again, blocked the river, created a dam, the dam eventually burst through and caused some destruction downstream. This probably happens dozens, if not hundreds, of times per decade, so it's a significant hazard. Also, just two weeks before we were there, a large earthquake caused this rock slide, it came out of a side canyon up here to the right. 14 million cubic meters, killed 14 people who unfortunately were hiking along the main trail to Langtang at that period of time, so we had to walk around to bypass this. Well, these kinds of observations led to the theory of Himalayan environmental degradation, which was proposed back in the 1980s and really operates something like this, that the mountain areas are experiencing a lot of population growth. This would lead to less land per family, especially as you go through multiple generations and the property is divided up, which would cause an increased demand for wood.
Wood is still the dominant source of fuel, so this is one area where these wood burning stoves would be more acceptable, more needed, and that not only is wood used for fuel, but for construction and also the leaves are used for fodder, for livestock. So the thought is, that would lead to deforestation, which would lead to local flooding in the mountains and slope failures along the lines of what we've talked about, and eventually the water and sediment would translate downstream to west Bengal and Bangladesh where you'd have flooding, sedimentation, channels shifting around and all the hazards and death and destruction as a result. So with this in mind, we went over to the central Himalayas of Nepal to test this theory. Also, this was a popular item in the media at the time. I remember seeing this article in Audubon Magazine and anything that has to do with baldness usually attracts my attention, so “Is Nepal Going Bald?”
Well, the World Bank came out with a report in 1979 that reported that between 1950 and 1980, half of Nepal's forests had been eliminated and by the year 2000, if that was to continue, all forests would be gone. It hasn't happened, but this is the kind of alarmist literature that was prevalent at the time, so I wanted to see to what effect forest cover was changing and if it had an effect on flooding and mass movement. So I went on two expeditions. One in 1984 that started at that Trishuli Dam at this location. We went up to the Langtang Valley. It took about 10 days to get up there, now you can drive, by the way, up there and then we went over the pass here Gyanga La about 17,000 feet and then back down toward Katmandu. 1987 we went through the Gorkha region and then up and down these valleys. That will get you in good shape, when you're hiking east and west across the Himalayas like that -- and altogether about 550 kilometers worth of traveling, and just to give you an idea what this is like, here's a trekkers map showing contours. You might be used to looking at contour maps with maybe a 20 foot contour interval. These are 1,000 foot contours --
And here you see our route and our camp numbers, so on some of these days we'd go down 3,000 feet, up 4,000 feet and the point is that every time we would cross a river, we'd -- my colleagues and I -- we'd stop and make measurements. So for instance, again, at low flow you can see where the high flow line would be. We'd make estimates -- measurements I should say, of the width, bankfull depth, hydraulic roughness, and use that to estimate what the bankfull discharge would be. What we found is when we went back and did the statistical analysis, is that the percent forest cover had no explanatory on the variation from one river to another in bankfull discharge. In other words, if you put a monsoon seasonal rain event on a landscape like this, the forest cover isn't going to make any difference because the slopes are so steep, the soils are so shallow, the impermeability is so low, that we saw even runoff in an undisturbed forest, which you would never see elsewhere on the Pacific Rim. I was trained in graduate school at Oregon State, where the link between deforestation and increased flooding is readily evident, so I expected to see more or less the same thing in the Himalayas but this was a good lesson in an early career for a geomorphologist because it showed you that place does matter and you get in trouble when you try to translate cause and effect in environmental change from one place to another without getting on the ground and actually collecting data.
Look at this. I mean, this is the landscape you might see in the Garhwal Himalayas or the Nepal Himalayas, where you might have one hill slope that is in continuous terraces like this for perhaps 5,000 feet and these terraces have been in place for a millennia or more. Probably not designed by Ph.D.'s in hydraulic engineering, but they're stable and they're very effective in translating water from the top of the slope down to the bottom. It may look, at first glance, like a lot of this is a stair step apparent topography, but in fact many of these terraces are constructed as ramps, so that the water is translated down slope in a ramp like fashion, therefore retaining more of the moisture on the terraces where it can be used for agriculture and causing less erosion. The better constructed terraces will have a bund a little berm on the outer edge of it to retain that water and keep it from cascading over the surface, because understandably when that happens you'd have erosion and a lot of cultural energy would have to be invested to maintain those terraces.
What effect do you think terracing like this would have on slope stability, in terms of the mass movement we've been looking at? Probably increases the stability and that's in fact what we found. These -- or a couple of the graphs, don't want to dwell too long on these, but the one down here really shows you the prevalence of slope failures in areas that were undisturbed by human activities, undisturbed forests versus the areas that were disturbed and the cross hatching bar here shows you the area that we observed that was a natural undisturbed forest versus the area that had been disturbed and you can see that there's less mass wasting, less in the way of slope failures in areas that are disturbed than you would expect, for the percent area coverage, and it's because of that effect I just described with terracing increasing the stability of slopes.
Also, remember the main central thrust I discussed earlier? Above the main central thrust you have much less in the way of mass movement than you would expect and below, where the rocks are less competent, you're receiving more rainfall, you have more mass movement than expected, and there's also a distance decay function. The further you are away from the main central thrust, the less frequent the mass movement. Now, here's one of the circumstances were humans do have a major effect on sedimentation and mass movement and that is the construction of mid-slope roads. Instead of constructing the road along a ride or along the valley bottom, it's been popular for decades to construct them in the middle of the slope, which means you have to cut the hill slope and then dump the cut material over the side, so side cast material, that's what's happening here, and you see it triggered slope failure here. All they did, is with a bulldozer, push it over the side. So if you put 150 to 200 inches of rain on that, what do you think will happen? So now there's been a move by the government of Nepal to put an end to these mid-slope roads and either build them along a ridge top or down on the valley bottom, but a lot of them are there and causing a significant source of sediment.
So our results were first published in this journal Mountain Research and Development and I just wanted to highlight this second item here. 84 percent of the variation of flooding was explained just by knowing the area of the watershed. The forest cover didn't matter, the slope of the watershed didn't matter, just knowing the area was enough to explain most of the flooding, and remember that this is monsoon flooding, not glacial lake outburst flooding. With respect to slope failures, the cause, the type of slope failures and the size vary by physiographic region. Mainly the distance from the main central thrust and also, what aspect slope are you on? South-facing slopes receive more intense solar radiation and the direct impact of monsoon storms so they go through wet and dry cycles, you see much more mass movement there. You see a lower frequency of mass movement in disturbed lands than in land where the forest cover is intact. Now, some of that is because the forest is intact on slopes that can't be converted into agricultural terraces, let's keep that in mind.
There's -- third point here, there's a positive feedback between stream side slope failures and floods. If you have monsoon floods, they're going to be undercutting the toe of hill slopes that lead directly down to the river. That drops slope failures into the river, causes the bed of the river to experience aggradation, rising in elevation, so what’s going to happen the following year? The monsoon floods are going to impact those same slopes higher than they did the previous year, triggering more mass movement. This is a very pervasive effect, it's hard to measure, but we saw it throughout -- saw evidence for it throughout the central Nepal Himalaya. It's something that an engineering structure cannot really reverse.
Finally, we can't help but concluding that seismic action and rainfall thresholds are most important in determining mass movement. Just last week, about eight days ago, was a magnitude five earthquake in this central Nepal region and it caused big series of slope failures, and they've had some major rainfall triggered landslides this year, throughout the monsoon season that had been reported by the United Nations. Place matters. That landscapes exhibit contrasting sensitivity to disturbance, disturbance from not just humans, but seismic action and rainfall, so whether you're above or below the MCT has more influence, really, than the impacts of humans, so we have to be careful, again, to avoid bias in concluding that one cause of mass movement in one part of the world is going to be the uniform cause everywhere. This has led Jonathan Phillips to write about the perfect landscape, kind of a play on the movie “The Perfect Storm” but his idea of the perfect landscape is that the laws of physics and chemistry operate everywhere, but the reason we have so many difficulties trying to come up with a general model of how landscapes evolve over time is because each landscape has an environmental history that has to be carefully documented.
So here's our straw dog, the Himalayan Environmental Degradation Theory and here's what we can conclude about it. That population growth does exist, there is less land per family as these large families grow and go from one generation to the next, the demand for wood probably reached a peak around 1950 at the end of munitions construction using wood burning fires in the Katmandu valley. Deforestation is occurring but not in the way that we are accustomed to think about it in the Pacific Northwest, clear-cutting. It's happening more, as people have learned, about the effects of deforestation, it's happening more in the form of lopping off individual branches from trees and therefore allowing the tree to live but harvest the wood on a more sustainable basis. You do have local flooding and slope failures, but I've hoped to have convinced you that most of this is because of natural factors. In the bottom box there that happens too, but really it's local rainfall in Bangladesh and especially cyclones, tropical cyclones that lead to storm surges that cause the devastating events that I described in an earlier slide.
So don't blame the subsistence farmers and woodcutters in Nepal for the problems that I've described here today. Here's an example of a forest where lopping is the more common way of harvesting wood than just cutting down the entire tree. This happens to be near a village where there had been some cutting of trees induced because a NGO had decided to help the Nepalese by bringing over wood burning stoves. Not the -- yeah, the kind that require cut wood. So, you know, if you go into some of these homes you see little smoldering fires in the corner, very unhealthy, lots of smoke and so the idea, let's bring in wood burning stoves, but it didn't require twigs to fire these up, it required cut wood and so actually increased the rate of deforestation around this village. By the time we got there, we're walking along and saw about three down of these wood burning stoves tossed into a deep gulley on the edge of the village. As the villagers had realized, this wasn't solving their problem. They need something that would be a more sustainable way of using wood, and so they've gone to this type of harvest instead. Also, keep in mind that land is precious up in the Himalayas for farming, so that here we're looking at an area where a landslide occurred. You can see the terraces that were terminated, taken out by the landslide. What's happening? The local villagers are repairing it. They'll put this back into production for the next growing season and that's very common to see. So it's in their best interests to create a stable landscape. So in conclusion, I'd say we can say three things. First of all, these modern techniques of measuring the rates of geomorphic change might have an impact on forming policy and of avoiding international conflict because we can now say a little bit more about the human factor. When do humans have an impact and when is it natural factors that cause the change instead? Also, these techniques help us to explain the spatial variability of hazards. It's not the same in the east as it is in the west and it's not the same once you get above the MCT as it is below the MCT. Second, I think that we come to realize by working in the mountains that scientists and policy-makers realize that most problems require training; experience, I mean on the ground, not just looking at remotely sensed imagery; and expertise, in both physical systems and human systems and how they interact, and finally, the mixed methods and theories including remote sensing, but also field techniques have enabled mountain scientists to help resolve this debate over human triggered landscape change and maybe try to repair the frequent disconnect between the findings of mountain science, policy-making and resource management. So, here we are at the Department of State and we look at ways to help resolve regional conflict and environmental instability. Hopefully, some of this work will contribute to that. Thank you very much.
So we have a few minutes for questions and microphones are set up on both sides of the auditorium if you'd like to ask a question, please move to the microphones and we'll be glad to entertain those questions.
Thank you very much for that very interesting presentation, you mentioned, I believe, that you thought deforestation in the Nepal Himalaya might have peaked around 1950? If so, could you go into that, explain that a little bit more please, very interested in that conclusion, thanks.
Yeah, the question is concerning my statement about when deforestation peaked and I should say that this idea that wood harvest peaked around 1950 is relative to the area around the Katmandu valley, where the British had built plants for constructing munitions, you know, in the previous century and a half, and those were fired by charcoal made by consuming wood, so that's what I had in mind and here's another example of where place matters. So, if I didn't make that clear, I at fault here because the rates and styles of wood harvests do differ from one place in the Himalayas to another, so for instance in the Everest region, there you see forests that have been, you know, devastated, removed, many times to support these large expeditions that were successful in climbing Mount Everest. For instance, the American expedition in 1963 had something like 900 porters and I know some people that were on that expedition and they talked about the big bonfires they would have every night and, you know, that had an impact on the wood resource. A lot of that has been -- the timber cover has been improved over time, but -- so the situation might be a little bit different there and my findings are with respect to the Theory of Himalayan Environmental Degradation, I should say they are constrained to central Nepal, the middle mountains where we did our work. Other people, namely, Jack Ives and Bruno Messerli, Jack Ives at the University of Colorado had a generation of students who worked on these same problems and really found the same impact that humans -- that human impact has been overstated in the case of deforestation leading to flooding and mass movement. Yes?
Thanks. My question is somewhat related to his since I had the same sort of interest in that statement, that the deforestation had peaked around 1950. I guess my question is the forests that do exist up in the middle mountains and the villagers or the subsistence farmers who harvest them, as you say they're harvesting them in more responsible ways by lopping rather than removing trees, but eventually you would think with increased population and only so much forest that there's going to be a conflict of resources, with more people and fewer trees to be able to lop off, and yet you -- I’m not saying this is a bad thing or anything, but you sounded somewhat optimistic about the whole process that at least for now, it's not really a problem. Do you expect that to be a problem in the near future or is it something that with responsible harvesting the villagers or the farmers will be able to sustain that kind of level of forestry for 50, 60 years? Thanks.
Yeah, it's a very good question and I think the answer differs depending about whether you're talking about Nepal or India because in Nepal what's happened is the local communities have more control over the management of the forest and this is largely a result of the women-led Chipko movement in the past few decades leading to more local control over the forest resource. Not the case in India and other parts of the Himalayas where federal government is still actually interested and they have an interest in promoting this Theory of Himalayan Environmental Degradation because it leads to foreign aid, so I don't think the basis of the Theory of Himalayan Environmental Degradation can really be sustained, but I think that the forest resource in Nepal is being managed in a more sustainable basis and as far as the impact of growing population, there's an out migration from the mountain areas to Pokhara and Katmandu valley, so that population base of these remote villages is not increasing as much as, maybe, had been forecasted in the past. Yes, over here.
Maybe it's a piggy back to that question about using the wood. Seems they're using that for energy, all your pictures are nice sunny days and then you talk about the rain, so it's not always sunny I’m sure, but the use of sustainable energy then, is the question and why are they still burning wood, are they using sort of other technologies and a corollary to that is in a different part of your talk you talked about upstream damming for power and the correlation, so my whole theme is energy and the correlation -- or the impact of what you're talking about.
Yeah, good questions and on the energy issue, first of all it's interesting to note that Nepal probably has the greatest hydro power potential in the world if you measure it by the usual techniques of relief and rivers and water discharge. The question -- the constraint is can you harvest it without causing these reservoirs to fill up with sediment in a short period of time, so it's interesting that Nepal is a net importer of energy and, you know, they should be an exporter if you just look at their resource base, but they're an importer and in fact a lot of these hydro power projects are financed by the Indian government so that they, the Indians, can import it to the northern India where industrial development is being pursued at a higher rate. You do see, like in the case of the Trishuli project, of course there will be local distribution of electricity that more than meets the needs of the local village but the infrastructure doesn't exist, the transmission lines to distribute it throughout the middle mountains in this incredibly rugged terrain. That's one constraint, so wood remains the main source of energy production, you know, attempts to bring in propane and other types of fuel, well again the roads don't exist to really supply these villages with anything that has made a major difference.
How about solar?
Yeah, solar -- we used solar to recharge our equipment as we went along. Sure, it could be used and I didn't see much evidence of it when we've been over there, but it would have a potential, absolutely.
You mentioned initially that the downstream countries implicate agriculture in this, so maybe you could just comment on crop growing, use of livestock, what's the contribution to some of the issues in these very hilly areas -- mountainous areas.
Well the -- from the point of view of Bangladesh you're asking, or the actual situation?
Yeah, okay, so in many parts of the world you get increased run off from agricultural land as compared to undisturbed forest, so again without thinking about the power of place it's easy to then jump, from the point of view of let's say West Bengal or Bangladesh and you're looking at huge amounts of water coming down the Brahmaputra and Ganges and blame it on Nepal, and of course there's very high rates of rainfall in the Himalayas of Nepal and Bangladeshis have said in the past they felt that it was accelerated by agricultural practices, but in fact when people, not me, but other researchers have gone out in the field and measured the water budget during the monsoon season on a terraced hill slope it shows that you have less runoff in those areas and it's also spread out more uniformly throughout the storm season than you do on undisturbed forest. It's quite the opposite of what you would find in New Zealand or Oregon. So I think the terracing's had a -- has been demonstrated to have a huge impact on the local water budget and can't -- also I should add that the further downstream you go -- this is -- now here I am worldwide generalization -- the further downstream you go, the larger and larger the water shed, the less effect that land use and land cover has on runoff, that's been shown in many, many studies. So, you could rely on that too, but I think it's important to show that even within the Himalayas of Nepal that agriculture isn't really responsible for accelerating runoff. Yes?
I’m just wondering whether there's unexploited value in the river runoff and the sediment, particularly from the Bangladeshi standpoint. Are they harvesting the sediment to make dikes or something, or is there other value that they're missing that they could concentrate on rather than simply blaming their upstream neighbors?
The only real use of the sediment made down in the lowland countries is -- and it is significant -- is to build levies, human-made levies and many times, in fact if you look at a satellite imagery of Bangladesh, that's where the communities are. These long linear strips along levies and that's where people go during the monsoon floods and hope that the water doesn't top the levy, it -- often it does. So Bangladesh, my colleague back at Kansas State, Bimal Paul, has done some interesting research on this. Bangladesh has built a number of raised platforms around the country, each one of which could maybe house a thousand people by design. In actuality, you might find 5,000 or 6,000 people on these during a monsoon season, waiting for the end of a particular flood event and because there isn't the infrastructure to evacuate people, they have rely on something like that, so other than levies, you know I can't really think of another potential use and I might add, Alan, that the French were contracted to come in and devise a nation-wide flood management scheme for Bangladesh. This would have cost many, many billions of dollars and I know one of the hydrologists who was involved in this and I saw the scheme, which would have involved building levies, using gravel by the way but also leaving gaps so that certain areas would have been flooded deliberately to protect other areas and once that part of the plan got out you could imagine that certain groups were disadvantaged by that plan and none of it was ever built and I think that was probably a good idea.
Hey Dick, thanks for this talk. I had a question. You zeroed in on one particular region and you made it very clear that you can't apply one set of conclusions across, you know, an entire large region. Do you have a feel for how many different regional analyses either are going on across the entire Himalaya or need to go on to do this kind of assessment that you've done here?
Yes, Rebecca, very good summary of work by other people was produced by Jack Ives, who I mentioned before, in a book called “Himalayan Perspectives” published, I’m going to say, around 2005, 2006 and that book is an update to a book that he and Bruno Messerli published back in the '80s called “The Himalayan Dilemma” and those two volumes do a very good job reviewing the literature, both the literature that reported findings that would support this Theory of Himalayan Environmental Degradation and then studies that tended to tear down those findings. So those two books, “The Himalayan Dilemma” and “Himalayan Perspectives” are two good summaries, but if you follow the journals, particularly Mountain Research and Development and also -- well, there's many journals, Geomorphology is another one. You'll see articles that look at other factors besides land cover, land use change, rainfall, seismic action and map the tremendous amount of slope failures and analyze the floods and are able to count most of the -- for most of the variability in those two disasters with something other than land use, land cover effects. So, just remember, there are some circumstances where humans do have an impact, especially in slope failures with these mid-slope roads and if they cultivate areas that are covered with loess, these dust storm deposits from Tibet during the dry monsoon season, when winds are blowing from the north, mantle the hill slopes in the middle mountains with loess. That material is very easily eroded and humans do have an impact there, but overall in that central part of the middle mountains in Nepal, other factors come to the forefront. Yes, one more I think.
Doctor Marston, if we try to overlay anticipated effects of climate change on the geomorphological baseline that you so well described, what sort of skewed, weighted results might you anticipate?
Yes, question about climate change is one that didn't even address, but it's of concern to a lot of people and generally the concern is what will it do the length and severity of the monsoon season, that's one concern and the other concern is what's happening with glaciers in the Himalaya, which is another one of my favorite topics but because of time I didn't discuss it here today. With respect to glaciers, people are worried about the percent of water that comes from glaciers and how that might change if they continue to recede. In the western Himalaya, where glaciers enter the arid lowland plain of northern Pakistan, along the Indus for instance, it's tributaries, glaciers might contribute 40 to 50 percent of the runoff. In the eastern Himalaya of Nepal, Bhutan and so on, it's probably much less, maybe nine percent, so the greater impact of glaciers receding, I think, will be not on water supply, but on these glacial lake outburst floods that I was describing earlier. Now, with respect to the severity of the monsoon, I've seen contrasting predictions on that and so I don't want to hang my hat on any one of those yet, but people are concerned about it and I think it's one of those cases where more research is needed. The main missing piece of the puzzle in understanding that, is that we don't understand very well the atmospheric dynamics of air masses moving up these incredibly steep water sheds and what happens in the valley as opposed to on the highland areas, so I attended a workshop here a month or so ago in town that one of the talks that was expressing concern over our lack of certainty about that impact. So those are the things that come to mind. All right, that's the end of our time, so thanks again for coming.