Science, Technology & Innovation

I spoke on behalf of the Cambodia Team at the Science, Technology and Innovation Forum during the UN General Assembly meeting on September 22nd. The event, sponsored by USAID and the New York Academy of Sciences was to build on the momentum generated from our Agency's conference- Transforming Development through Science, Technology & Innovation.

The forum featured an interactive "science fair" to showcase examples of currenty low-cost, life-saving technologies, that have or can have a transformational impact in the developing world. These products from the public and private sector demonstrate the great potential to solve current and future development problems.

The forum was interested in the Kite Aerial Photography (KAP).

The KAP was designed to obtain site visuals when maps were not available.

To see the clip of the presentation on the project, please see:


For the rest of the presentations as well as the write ups please see: http://www.usaid.gov/scitech/

Bentonite Injection

In November and December, EWB was focusing on the repair of a few small but potentially dangerous leaks in the earthen embankment. There were three outflow points where water could be seen flowing out on the downstream side of the embankment, and we were able to locate three inflow points on the upstream side of the embankment. After digging test pits at the inflow points, we found pipe-shaped voids, around 1.5"-2.5" in diameter, that we believed traveled straight across the embankment. The voids are believed to either have been old termite tunnels, or left behind from decomposed tree roots.

The proposed method of repair was bentonite injection. Bentonite is a material with very unique properties. It is a naturally occurring material found in the earth - a clay - which can swell up to 16x its original size when it comes in contact with water. This property makes it a useful material for sealing leaks, waterproofing buildings, and many other applications where water flow needs to be stopped.

While bentonite would help us fix the leak, we had a minor problem to overcome - where could it be purchased in Cambodia? We soon found out - nowhere! So, we looked to our closest geographic neighbors - Thailand and Vietnam. Through a material supplier located in Siem Reap, we were able to make a purchase from a Thai supplier. After the purchase, two weeks later, the bags of bentonite powder were delivered to HT's office.

Special Delivery

After researching and consulting with our project mentors, we started experimenting with the bentonite and water to determine what the mix proportions would be that would yield the most desirable end product - something that would plug the "pipes", the voids, completely. The ideal mix would have a low enough viscosity to pass through the 2" water pump, yet have a high enough bentonite concentration to expand and "solidify", thus completely filling the voids. We used a bentonite slurry that was about 11-12% bentonite powder to water, by weight. In this application, measurements did not have to be very precise, so out in the field, proportions were altered slightly as necessary to make the pumping operation continuous and effective.

Left: Bentonite injection technique
Center: Things get real! Dirty, that is
Right: The setup - Filtering water, the mixing barrel, pumps and hoses

With the fluid slurry mixed, we started pumping by inserting a length of typical 1.5" diameter flexible hose as far into the inflow point as possible. Things were going well - messy, wet, dirty, but so far so good.

Meatballs, bottom of photo

Once the voids were full, we had to plug the inflow point to prevent the slurry from draining before it expanded fully. Our solution - meatballs! Well, they looked like meatballs anyway. Excess bentonite that was starting to clog the pump was removed from the mixing barrel, and shaped into balls the same size as the inflow point of the pipe shaped voids. Once we had pumped slurry through the embankment, we quickly jammed 8-10 meatballs right in the void and blocked any slurry from draining out. Now, theoretically, the slurry was inside the embankment, and slowly, the water should have been permeating through the bentonite powder, expanding each particle until the mass of slurry had filled the whole shape of the void.

To finish the repair, a layer of bentonite powder was spread over a 3-meter long strip, covering the three inflow points. This area was then backfilled with clay and protected with a layer of rip rap.

The downstream area has been dry since the bentonite was injected. The real test will be the upcoming rainy season, which will start in May/June. We'll keep you posted!

The Cambodia Team goes to India!

After flying for what seemed like forever the team met up in Chennai, India, for the EWRI of ASCE's 3rd International Perspective on Current & Future State of Water Resources & the Environment, held on January 5-7, 2010.

From Left to Right: Jason , Monica, Jess, Matt, Bryse, Tim

Matt, the project lead, gave the presentation, which by far was the best, but, I could also be a bit biased.

As for India, it definitely was an intense and rewarding experience. Those of us who had the time to travel a bit longer got a well-rounded view of India.

Including, the large city of Chennai, where in order to cross the bustling streets, we had to play Frogger-- with only 1 life. We continued to travel into Mamallapuram where we stayed on the beach and watched many cultural and traditional dances during a large festival. Afterwards a few of us went up north to Darjeeling (a city 2000m above sea level), to go trekking.

The most amazing view was being 3000m above sea level and seeing the night sky, including the Milky Way, unobstructed by light pollution.

After our first experience with the trains in India, we arrived in Varansi (a very religious and spiritual place) where we witnessed the festival of new beginnings and the solar eclipse. Granted it was foggy out.

In the end, there are a few things I learned while in India:
1) Public Urination is common, even if there is a bathroom around the corner.
2) Nobody is every in a rush, except when it comes to driving.
3) Drivers are perpetually on the horn.
4) "India time" refers to 6 hour delays or more.
5) Anything goes.