Monday, March 10, 2014

A Focus on Watersheds – Part 2: Stone Bands, Micro-Catchments, & Check Dams

Looking east over the stone bands within the Gersale Watershed enclosure in Konso

The Gersale Watershed project started nearly 10 years ago.  Each year since the project began, hundreds of participants from the surrounding villages have utilized a portion of their time waiting for the year’s rains to begin by improving their neighboring watershed.

During the first day of this year’s watershed project, a simple but effective brush fence was constructed to expand the areas under the protection of the community.  Since then, the villages in charge of managing this watershed have put its residents to work constructing various stone and soil structures along the hillsides. These structures range from stone bands, micro-catchments, and check dams and are built with the intention to prevent soil and water from freely leaving and flowing downhill. With the soil stabilized and the water slowed and enabled to penetrate the soil, plants can grow and even thrive here.

Kept free from animals and left for light harvesting of grasses and tree products (ranging from cut-and-carry fodder and firewood to fruits and construction materials) will be sold for the benefit of community projects and social services.  The next blog entry regarding this watershed project will cover the tree transplanting event, which are expected to take place sometime between late March and April.

Below are a series of photos and descriptions from the past month and a half of work within the Gersale Watershed, where I’ve been spending my Saturday mornings.

Stone Band Work 1: The process of building a stone band starts with digging trenches roughly 20 cm deep along contour lines of a hillside.  Stones are sourced in the immediate area of the stone band work, either picked up from the ground or unearthed.  Then, the stones are brought to the trenches and placed strategically at a height of about 35-50 cm.  

Stone Band Work 2: Work parties spread out and take on different portions of the Gersale Watershed.  The work starts at the top of a slope and then moves downhill. The spacing between stone bands are closer where the the slopes are steeper - the steeper the slope, the closer the bands are spaced.

Stone Band Work 3: Stone bands run along hillsides where they will provide stable grounds for trees and shrubs to be planted during the rain season.  To the left bags of food or drink or left to hang where people will gather during their lunch break or when the work is finished. 

Prepared to Work: The essentials in the watershed - chekka (a calorie rich, local beer), water, and a tool to dig with.  

Micro-Catchments 1: In some portions of the watershed, free form structures are made in preperation for transplanting tree seedlings in the coming month.  

Micro-Catchments 2: These soil structures will slow water so that it will be made available for the trees that will soon be planted here.

Check Dams 1: Stone check dams are built in places where water and erosion have already started to make a dramatic impression.  Over a few years time, a small waterway can deepen and widen.  With increased water flow, the surrounding soil is put at a risk of being washed away. Check dams both catch soil and slow water.

Check Dams 2: In this waterway, a group of  workers are constructing a series of check dams to prevent soil and water loss.  These check dams will work together to fill in the water way by catching soil that flows out with the water.  Spillways are intentionally built into the check dams so that the pressure of the water doesn't become so great that it would breach its check dam and jeopardize its effectiveness entirely.  

Check Dams 3: A series of check dams are being constructed in this waterway to reduce the rate and severity of soil and water loss.

Fellow Stone Band Workers: I really apprecieated these guys for making me feel welcomed in the watershed.  I was quickly invited into their fold of stone band construction and helped in the process as I could. 

Working with the Crew: Taking a photo opportunity to stand upright for a second.  Much of this work demands being bent over to dig trenches, remove weeds, unearth and carry/roll stones into place.  

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