For all you geologically inclined...

This is a project I worked on for our trip.

Landscape Degradation in the Himalaya

Christine Rahtz
UC Geology 2011-New Delhi to Leh

Table of Contents

Introduction………………………………p. 2
Anthropogenic Influence…………………..p. 3
Precipitation and Erosion………………….p. 5
Mass Movement………………………….p. 8
Future Research…………………………..p. 10

There is no doubt that erosion processes of the Himalaya are quite complex, and affected by several components, including tectonics, anthropogenic land use and vegetation, and glacial and fluvial processes. The relationship between climate, tectonics and rates of erosion in the Himalaya is one of extensive scientific exploration.  The connection between erosion rates and precipitation in a region of tectonic uplift is widely debated and not well known.  Some hypothesize that the linkage is characterized by a cycle of uplift, followed by increased orographic precipitation, higher rates of erosion, unloading of the crust, and further uplift.  There are many causes, natural and unnatural, of landscape degradation and soil erosion in this environment. This webpage explores and explains the complexities of the erosional landscape of the Himalayas. 

Anthropogenic Influence

“The construction of highways may actually accelerate some of the geomorphological processes in the region,” writes Lewis Owen, a geomorphologist at University of Cincinnati (1996).  Road construction in the Himalaya can create many problems, including increased erosion and landslides.  Road construction is important for local people, it allows them mobility and access to resources.  It is however, extremely dangerous, and thousands die in the building of roads through these mountains (Owen 1996).  These roads do not last very long either.  In my travels through India, I learned that patience is an absolute must.  There were several times during our two week trip that we had to sit and wait for a slope failure to be cleared from the road.   
Deforestation is another human induced activity that can lead to landscape degradation.  Vegetation can hold soil in place and reduce erosion rates.  The removal of trees and plants to build roads or villages can accelerate soil loss.  The higher the altitude, the less important this factor becomes.  At high altitude, vegetation cover is much lower, but the climate is also much more arid.  At lower elevations, vegetative cover is essential to holding saturated soil in place and maintaining the slope surface.  When it is removed, the increased surface area is vulnerable to the effects of rain.  It is clear that vegetation cover and precipitation are closely linked, and affect the landscape degradation of an area.

Precipitation and Erosion

Climate is a major factor in erosion in the Himalaya.  The range has a distinctive precipitation pattern called the monsoon.  In the summer, the foothills are subjected to extremely heavy rainfall.  This causes intense flooding and landslides.  In the spring, glacial meltwater causes further erosion on the unstable slope, and avalanches are also common (Owen 1996). 
Fluvial erosion plays a large role in the degradation of the Himalaya Mountains.  From the Indo-Gangetic Plain (a large floodplain made up of sediments 10 kilometers deep) to the high, crystalline Himalaya, water erosion is a major factor.  As these mountains uplift (at incredible rates, about 6 millimeters per year!) they are cut down almost as quickly, creating immense, beautiful valleys and river terraces. The rivers carry this sediment out of the range.  You can see the different sediment loads that the Zanskar and Indus Rivers (pictured above) are carrying.   The Zanskar River is a muddy brown color, indicating that its sediment load is high, and particles are suspended in the water and being transported out of the range.  The Indus River is a bluer color, because the sediment did not remain suspended but was deposited along the river bed.  Thus, I would say that the Zanskar River has more erosive power than the Indus, because of its more effective transport. 

It is hard to measure overall rates of erosion, because a mountain range has so many variable parts.  However, using biotite dating in gneisses, UC students and faculty dated strath terraces and concluded that on range margins, erosion could be up to 15-20 mm/year.  That is incredibly powerful erosion.
At higher altitudes, glacial incision is the major erosive control.  As the glacier moves slowly with gravity, it scrapes along the bedrock surfaces, and the glacial melt incises the substratum.  Glacial erosion creates characteristic U-shaped valleys, like the one pictured to the right.  Glacial lakes that were dammed by ice can catastrophically fail in an outburst flood. Snow and rock avalanches also often coincide with glacial landscapes.

Mass Movement

It is hard to tease out one causal force for a landslide event.  Movement along a fault can set into action large scale landslides.  A landslide is affected by tectonics, but also by precipitation.  This may have been climate driven; the precipitation gradient was high around the time these landslides occurred.  A study from 2004 used sediment influx measurements to make inferences about the role of precipitation in large mass movement events.  They found that rainfall increases pore water pressure, “priming the
landscape for larger and more frequent slope failures,” and that these failures often occur late in the monsoon season (Gabet et al., 2004a).
Even though the slope failures pictured seem so big, they are actually not as erosionally “effective” as fluvial sediment transport.  This is because, although a huge mass of material was moved, it was not moved far.  After the fall (both were dated to about 8,000 years ago), this mass has remained in the exact same place. 

Slope instability is the result of many factors, including bedrock and soil type, angle of slope, vegetation cover, and influence of climate.  In the talus cones pictured above, all of these variables come into play.  Above the cones one sees a pro-talus rock glacier.  During the winter this entire slope is covered in snow, and interstitial ice forms.  The melt from this ice leads to even more slope instability. 


Future Research
There is so much more to be explored in understanding the relationship between precipitation, tectonics, climate, anthropogenic influence and erosion in the Himalaya.  This research is becoming especially important because of global climate change and all of its implications.  Understanding the present is the key to the past:  If scientists can piece together an erosional history of the mountain range, then we can better recognize erosional patterns of the present, and better predict erosional patterns of the future.  What is the effect of climate change on Himalayan landscape degradation, and what does that mean for the people of this range?  What predictions can we make about future regional geomorphology?  It is an immense mountain range, with immense possible resources and research opportunities.


Out of the mountains and into Leh…

We finally made it back to a city, and oh, how I missed it!  Just looking around at cars and people and even cows felt good.  I laid down in my bed in my hotel and savored it.  Of course, that could only last a few minutes, since I had to go see Leh!  You’re only in India once, right? 
The town was cool, but Leh is very touristy.  We hit it at the end of tourist season, but we still had to pay tourist prices!  I really enjoyed shopping there.  Unlike stores back home, these shops would offer you tea, sit you down and pull every single thing off the shelf to see if you are interested.  The tea is good, and I bought two beautiful scarves to take home. 
On top of that, I got to visit a beautiful monastery, and see the biggest Buddha I’ve ever seen! 

It was really good to see the cultural aspect of the country, as well as the geological.  All in all, I had an amazing time, but by the end, I was ready to go home to see my family.  It was a journey I’ll never forget.
The cow and I were good buddies.


Roughing it...

Enough of the hotels.  After a few days, we began our 7 day camping stint.  This was the real mountain exploring experience.  We have been steadily increasing in altitude, and people seemed to be doing well.  The side effects I felt were trouble sleeping, strange dreams, and an occasional headache. 

We got to see some marine fossils at 4,400 meters altitude.  Remnants of creatures that lived in a warm, shallow ocean millions of years ago, now at the top of the world.  If that isn't evidence for some serious uplift, I don't know what is.     
Not only have we seen serious uplift, we're seeing crazy downcutting too.  The landslides on the trip have been bigger than any I've imagined.  Landsliding is such a scary problem in the Himalaya mountains, and many have lost their lives because of them.
The most powerful “downcutter” however, is not landslide erosion, but glaciers.  Before this trip, I had never seen a glacier (except on TV), and I’m sure that I’m not alone in that.  Well let me tell you, I was really eager to see one (but that’s probably just the nerd in me).  The hike was intense: a gain in altitude of about 1,500 feet, and a 15 kilometer round trip.  The terrain was not nice either, it was mainly rocks and boulders perfect for stumbling over, or catching a foot on. The air is thin, so even if you are in good shape, you have to move slow.   
View of the Glacier

I think the climb to the glacier may have been the physically toughest thing I’ve ever done in my life. 
I also think the dinner I ate that night was the best food I’ve ever had in my life.
Our campsite at the time was next to Kaiger Lake, a glacial lake near Tso Moriri, and one of the most beautiful places I’ve seen in my lifetime.  The water was ice cold, but it was clean and I wasn’t, so I jumped in.  WOW, was it cold.  You’d be surprised what you’ll do to wash up.  I love camping!


And we're off...

The plane ride wasn't bad, it was 14 hours, but I mainly slept.  It was a polar flight, which was really cool, I got to see the ocean completely frozen over!  We arrived in New Dehli in the evening (I was so jet lagged, I have no idea what time it was) and the first thing I noticed was the heat.  The air was heavy and hard to breathe, and smelled stale.  We went from a plane to a bus, and the traffic was terrible.  I remained in relatively good spirits for the drive (although my snoring might have dampered the spirits of my classmates). 
View from the plane.  This was taken at 12AM local time!

I woke up the next morning, sleepy but pumped to really begin this trip.  We left our hotel in Havali Kunta, Panipat, and began the long drive across the Indo-gangetic plain.  It's a large, flat floodplain directly south of the Himalaya range.  It is made up of 10 kilometers of sediment, all the soil that runs off the mountain range.  I was amazed to see the vast flat area.  There were macaques running all over the place.  We spent a lot of time driving.
Menali 9/4/11
We arrived in Menali  around 1 AM, after finishing our 17 hour bus ride that day.  I never wanted to see another bus again.  Ever.  The view I woke up to was incredible.   Our first  geological stop was the Beas River bed.  The main thing that hit me about this place was the incredible size of things.  The scale of everything was huge!  Just huge!  Boulders the size of elephants were scattered haphazardly through the area.  It took some seriously fast, strong water to move those things around.  I was seeing some of the affects of the glaciers on the landscape. 
Menali was a cool town.  It was kind of hip and a little bit touristy, there was a main square for shopping and a lot of places to eat (I told you, I talk about food a lot).  I went out with a friend of mine, and sitting alone at the restaurant earned us a few strange looks.  I got a delicious vegetable and rice dish.  We found a slug the size of a cucumber.  There were other exotic animals walking the streets, mainly stray dogs and a few donkeys.  It was hard getting used to not drinking out of the faucet, and this was the first night I remembered not to run my toothbrush under the water.

Jispa 9/6/11
I saw as I traveled through India how different it was from one town to the next.  Jispa is a good example; it was a world away from Menali.  It was a simple, quiet town.  If you could even call it a town.  It was more like a cluster of buildings along one road.  My favorite part about Jispa was the prayer wall.  It was a long, stone fence along the road, but on each stone a mantra was carefully carved.  This town was also the first one we gave water filters to.

One of the people that came with us on our trip raised money to bring water filters and donate them at schools and monasteries that we pass through.  Another student brought water testing supplies and ran experiments on the presence  of fecal ecoliform in the water.  And yes, based on Julia's tests, the filters were MUCH needed. 
Several of our group went over to Jispa's monastery and school. It was opened by the Dahlai Lama in 1994.  The concept of personal property is somewhat different in India, and no one cared if we walked in and looked around.  It was not the building, but the children in it that captivated me.  They were absolutely darling (as children often are).  It felt really good to be a part of providing these kids clean drinking water.