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September 2005 |
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Reflections on Ethiopia
John Krahn of GEO-SLOPE and Professor Lee Barbour of the University of
Saskatchewan recently traveled to Ethiopia as part of WHIST (Water
Harvesting and Institutional Strengthening in Tigray), a project funded by
CIDA (the Canadian International Development Agency)
and managed by
Agriculture and Agri-Food Canada - PFRA
(Prairie Farm Rehabilitation Administration)
to help the
Ethiopian government reduce the impact of drought and move toward food
self-sufficiency. John and Lee were in Ethiopia to
provide mentorship and technical training in slope stability and seepage
analysis as it relates to the construction of earth embankment dams.
The Ethiopian government, in an effort to increase local food production, is
constructing earth dams to store water for irrigation. 
These micro dams, which can reach heights of 20 meters, have
largely been constructed by hand labor as part of the work-for-food
program in which the food payment is often Canadian wheat. While this program
has provided much-needed work and food, it has not always resulted in the
desired quality control and material compaction of the dams. The hand-placed
rip-rap however is beautiful. There is now a desire in the Tigray region to
design and construct these dams on a more technical basis, and thus the desire
for a workshop.
A hand-constructed micro-dam in Ethiopia
John reflects on their experience:
After an arduous four day trip to Mekelle in the Tigray Region of Ethiopia, we did indeed
conduct a five day training workshop. The following two photos show the classroom
and workshop participants. On the right, Lee Barbour is providing
some one-on-one assistance.
Ethiopians are an incredibly warm and friendly people. They love socializing and at almost any social gathering they have a coffee ceremony. We were privileged to have the opportunity to partake in the coffee ceremony shown below. The coffee is served with bread and popcorn and with the sweet smell of burning incense.
Lee and John participating in a coffee ceremony
While reflecting on our Ethiopian adventure during the long plane ride home, we realized that this was just another small example that GEO-SLOPE is having a global impact.
Function Estimation in SEEP/W
As with all numerical models, defining reasonable material properties
and functions in SEEP/W can sometimes be a challenge. For some
simulations, the solution is not particularly sensitive to a specific
material property and sometimes the solution is extremely sensitive to
the defined material property. However, in the early states of a
numerical modeling project, it is often good practice to start with an
estimate of the material property functions. Simple estimates of the
functions are usually more than adequate for determining the importance
of the various properties for the situation being modeled. It is good
modeling practice to first obtain understandable and reasonable solutions
using estimated material properties and then later refine the analysis
once you know what the critical properties are going to be. It can
even be more cost effective to determine ahead of time what material
properties are going to control the analysis and then decide where it
is appropriate to spend money obtaining laboratory data.
To help generate reasonable estimates of material property functions, we have built several predictive methods into the SEEP/W program that make it possible to quickly obtain an estimation of material properties and which will help you move ahead with your modeling program.
In SEEP/W, there are only two material property functions that are used for an analysis: a volumetric water content function and a hydraulic conductivity function. Both of these functions can be estimated by defining a simple and easily measured grain-size curve.
Watch a video
to see how these functions can be estimated quickly and easily.
Specific details about each of the predictive methods available within SEEP/W are contained in the GeoStudio 2004 engineering book called Seepage Modeling with SEEP/W: An Engineering Methodology.
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