Thursday, December 13, 2012

Groundwater Powered Grain Mill In The Kumaon Lesser Himalayas

What is this mountain made up of?

Rocks off course. In this case the Deobang Formation dolomites and phyllites of the Lesser Himalayan Sequence. But a not so insignificant volume of this mountain is groundwater. Say 2% or 5% or locally near a fracture zone or a section of  weathered schists and phyllites maybe somewhat more.

Groundwater plays a big role in Himalayan farming economies. The point was driven forcefully to me as I made a traverse from the village of Shama to the village of Gogina which I covered in my post Interactive Geologic Map and Cross Section of Kumaon Lesser Himalayas.

During this traverse we came across a stream. Our hosts pointed to a small hut near the stream and told us that it was a water powered grain mill. My friend (many thanks Swati Pednekar!) has compiled a small video of that mill. Check it out. That's me in a blue shirt and blue cap looking intently at some mylonites and augen gneiss.

The pipe you see leading up to the hut brings water from the stream and powers the machinery that runs the stone mill. But.. you will say. .. this is surface water. Why do you call it a groundwater powered mill?

I say that because the stream that is powering this mill is located in a watershed not connected to any  glacier. You can see the outline of the watershed in the image below and the location of water powered grain mill within it.

The glacial Himalayas are far to the north several ranges away. I have annotated  Ramganga river and its source Namik glacier. This stream I am talking about joins the Ramganga river.  My hosts who are locals told me that the mill runs all through the year. So how does the stream manage to keep flowing well after the monsoons through the winter months and into the high summer if there is no glacial melt to  provide water? It does snow here a few times in the winter but there is no permanent snow cover. After falling the snow melts in a few days. A larger fraction of the stream flow I am guessing is provided by groundwater. Post monsoons, groundwater discharge through springs provides enough water to keep this stream perennial.  The fractured metamorphic rocks of the Lesser Himalayas are prolific aquifers.

The popular picture of Himalayan water use is one of vigorous streams sourced by high glaciers. But especially in the Lesser Himalayas, communities live far away from glacial streams. They grow up to three crops per year. Agriculture takes place not just in glacial river valleys but also on the uplands on terraced hill slopes and plateaus and on the back of dip slopes. Far above from the big glacial streams, farmers and communities rely on groundwater like the farming community in the picture below near the village Shama.

Digging dug wells and tube wells is too laborious and expensive and hindered in many places due to a lack of road connection. Lift irrigation too is expensive. Groundwater is therefore accessed where it discharges as springs along hill slopes. In the fractured rock terrain of the Himalayas springs are common. Farmers channel them into their fields, use spring fed streams to power grain mills and build temples around them as a mark of reverence. The temple in the picture below is from the village of Gogina.

Earlier this year I posted on a paper that studied the water budget of a section of the Nepal Himalayas and which concluded that groundwater contributes more than snow and glaciers to the annual discharge of rivers in that region. A similar estimate may apply to the Kumaon region water budget too. There is a very broad zone of the Lesser Himalayas in Kumaon which is not glaciated and therefore rain water is stored mainly as groundwater before discharging into streams and rivers.

Finally here is an interactive map of the location of my geological traverse along with the location of the grain mill (green placemark).

View Berinag and Munsyari Thrust Faults Shama Gogina Road in a larger map

Discussions about climate change, Himalayas, and water, generally focus on the health of Himalayan glaciers. This is indeed a valid concern since glacial rivers provide water to valley bottom farmers and the north Indian plains. However, thousands and thousands of farming communities within the Himalayas live on upland watersheds not connected to glaciers.. like the one I outlined in the image above. Their livelihoods will depend in part on how well they manage their groundwater resources. Here, geologists do have a major role to play in generating and interpreting the basic data on groundwater availability and helping farmers evolve best management practices.


  1. I'm enjoying the posts from your trip -- interesting and great scenery!

  2. thanks Hollis! its a very beautiful part of the country..

  3. Enjoyed your post.
    I used to live in Kumaon as a schoolgirl. Suddenly one night a spring erupted just outside my bedroom window. It gurgled pleasantly for almost the whole year I think, making a wonderful bubbly sound that I listened to before dropping off to sleep-- a memory I cherish.
    As a kid, on a trip to Shimla, I remember walking miles and miles, stopping en route to drink water spewing from rocks on the wayside.
    Years back, I have seen in the North Bengal region, the locals use bamboos, slit in half, leading from the jhoras to a tank outside their home. They cultivate fish in these tanks taht are constantly replenished. The govt was also encouraging these 'jhora fisheries'.
    Do these hills still have enough water for all these streams?

  4. L- thanks for sharing those memories.. regarding whether there is enough water I think the situation might vary from region to region depending on how agriculture and water use is being managed. In Kumaon in the area I was traveling farmers are still getting 3 crops a year and were not suffering shortages. But this region is quite remote. In Himalayan resort towns and regions closer to the plains where there is a boom of "farm houses" being built... i think these are areas where there are or will be water shortages if proper management is not put in place.