EWB-NY Cambodia Water Project

Bentonite Injection

2010-02-06T02:51:00.014-05:00

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!

2010-01-28T22:20:00.005-05:00

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.

Downstream O Ta Bet

2009-11-24T02:30:00.010-05:00

A group of explorers set out to track the downstream path of the mighty O Ta Bet

As part of the downstream canal planning, and the FWUC organization, HT arranged for a group of us to meet and walk the entire length of the downstream O Ta Bet. The group included village chiefs, FWUC members, HT/CTO members, and EWB. As we walked, the village leaders explained where the stream flowed in relation to the Balang commune boundaries. They also pointed out how the water was currently being managed by the farmers - a system of man made dikes and diversions led the water from rice paddy to rice paddy quite effectively. GPS points were taken during the walk to trace the path of the O Ta Bet, for the purpose of canal planning in the future.

Chai, Sourneang, Sovann debating... should we have turned left at that tree back there?

At each twist and turn (or, after we had waded through a rice paddy where the water was knee deep) the group would take a short break in the shade to discuss where we'd been and where we were in reference to our map... and to check for any pesky leeches that were trying to get a free ride on our legs!

Following Bok Kron's sure-footed steps... and trying to move faster than the leeches.

As we made our way downstream, we stopped in to a crocodile farm whose owner has recently decided to take on relatively large scale dry season rice farming. Here, we saw what could become more commonplace in the future if more water is available during dry season. Water was being pumped from the stream to irrigate elevated fields of dry season rice seed. This was interesting to see, as we found out that the soil here absorbs water quite rapidly, and thus requires a large amount of water to remain irrigated - ie, placing large demands on the water supply during dry season.

Dry Season rice experiment at the crocodile farm: water pumping operating in the background. O Ta Bet is to the far right.

After having a rejuvenating glass of tea at the crocodile farm, the expedition continued downstream, finally making it to Bok Kron's daughter's house on the main road. Here, I got a glimpse into the rice harvesting process, and chatted with her family about the rice yields they were getting this year. Finally, our day completed with a homemade lunch and a de-briefing meeting where the FWUC and HT discussed plans for canal development and reservoir maintenance.

Prioritizing the canal construction with the FWUC

Even though 90% of the spoken conversation occurred in Khmer, I received translations from Chai, and it was good enough to get me through. I have to say, it was one of the most extraordinary days of my involvement on this project thus far.

Repairs & Current Work

2009-11-19T01:34:00.006-05:00

Localized erosion

Basic repair items that are being addressed now are erosion along the downstream embankment in localized areas. Eroded areas will be backfilled and compacted, after proper surface preparation has taken place - removing grasses and leveling uneven and gullied soil. Erosion along the downstream wing wall returns will be filled in with rip-rap. Erosion has occurred here because it is exposed to foot traffic, fishermen who climb down the rip-rap along the side.

Erosion below Monitoring Well #4B

Each set of monitoring wells had an additional well installed at the downstream toe. Now there are four sets of three wells per set. This well will give a third plotting point on the phreatic line graphs, which we use to show the behavior of the water through cross sections of the embankment at four locations. The data will also help us in determining the most effective elevation to locate a toe drain just above the downstream toe.

As may have been mentioned at some point on this blog, there has been some leakage visible at the downstream embankment. We have monitored it visually and through the readings captured at the Monitoring Wells. For the last few months, the conditions have remained stable, which is a good thing, however it can't be left to leak for the long term. Our plans to plug the leaks have taken several twists and turns. The best case scenario for fixing the leaks has always included Bentonite, a naturally occurring clay which carries the unique inherent property that upon contact with water, it can swell up to 16x its original size. We would be using sodium bentonite in either powder or pellet form, and would spread it over the upstream embankment and insert it into potential inflow points to form a "plug" that would seal reservoir water from traveling through the embankment. However, Bentonite is not commonly used in Cambodia, and so we had to look elsewhere for material suppliers. We have just received pricing from a Thai supplier, and looks like we could receive material within two weeks. (PS, if any of our blog readers have information on bentonite suppliers in this region of the world, we would love to hear from you, for future reference.)

While this may solve the problem on our hands now, once the reservoir is fully turned over to the community, it will not be so easy to reach out to a Thai supplier, purchase material, and get it to the site... Something we're trying to start, as we perform maintenance and repairs on the embankment now, is getting the high level FWUC members involved directly. Participation of the FWUC is essential now, because they will be responsible for operating, maintaining, and inspecting the dam and watergate in the long term. A long period of overlap with EWB, HT, and FWUC all participating in routine dam inspections and monitoring procedures will help to ensure the success of the project's future management.

The Project

2009-11-01T03:28:00.009-05:00

Looking North along the main embankment

Back in Siem Reap, and I must say it feels good to be here. I arrived about a week ago, after a whirlwind 17 day tour of Asia via the TransSiberian Railway (but that's another story, for another blog!) My last visit out here was in early 2008, in the very dry and dusty month of January.

Having just emerged from the rainy season, Cambodia seems like a different place in October - full of vibrant green colors, lush rice fields, tree limbs full of flowers and fruit, and the occasional afternoon or evening rain shower to cool the hot air.

I made my first trip out to the watergate early in the week, a day or so after I arrived. The first thing I noticed was that the ride to the site was surprisingly pleasant, and much quicker than I remembered... it took me just a minute to remember that the roads had recently been topped out and leveled by the military with laterite. What a difference! The second thing that I noticed was all the water flooding the rice fields, which I learned was from the reservoir. As Chai and I approached the watergate, again I was struck by the colors of the scene around me. The burnt orange of the laterite road, bright blue water in the reservoir, and the white/gray concrete of the watergate - it was quite beautiful. Chai and I walked the length of the main and north embankments, looking at the state of things in general after the past weeks of storms, and I reacquainted myself with the landscape.

I couldn't check out the Vetiver Nursery during my visit (due to the recent storms). The culverts on the south embankment are in good shape, and there were no worrisome wet areas on the downstream side of the embankment (though the water level is somewhat low right now, so none were expected). While at the site, Chai and I went through the latest version of the Operations, Maintenance, and Inspection Manual - a work in progress that is coming along well. I've been working with HT, analyzing some recently collected demographic and agricultural data from the villages surrounding the watergate. This information will be the basis of our Baseline Year Project Assessment. EWB's intention is to compare data over the next years of reservoir operation to see the impact that the project has had on the agricultural prosperity of the commune.

Structurally the embankment and watergate are in good shape. They weathered the recent storms very well, and that's encouraging for the future because Typhoon Ketsana was said to have been the worst storm to hit Siem Reap in years. Unfortunately, it seems that another storm is headed along Ketsana's path, Typhoon Mirinae. We'll see how things turn out as that storm develops.

Marathon PRA

2009-10-22T01:57:00.004-04:00

Sourneang with the men's group

Bouny and Arwen with the women's group

"Participitaory Rural Appraisal (PRA) is a process which is used in development programs worldwide to help rural communities. PRA consists of a series of participatory exercises which help community members better assess their history, resources, and overall situation as concerns agriculture, health, education, and other important areas. Focused on the use of local resources, PRA can help provide a framework for a community's sustainable, long-term development." -PRA Handbook

Typhoon Season

2009-10-04T03:11:00.002-04:00

The good news is the reservoir stood up to typhoon Ketsana well with no visible damage. The bad news is typhoon Parma is on now heading this way. Right now, the reports are saying this next storm is moving more north so the effects should be less here in Cambodia. But it sounds like Parma is big enough that there will be an impact to this region even if it does continue north.

Typhoon Ketsana- water, water, and more water

2009-10-01T01:09:00.004-04:00

At this point, I think all of Cambodia is flooded. I've been wading through knee high water to get to town, which isn't even bad in comparison to other locations where the water is up to people's heads. My bike (the awesome new green bike that EWB now owns, we're putting the logo on it!) can't make it through the water, and the motos and tuks can't get through either. I will post pictures of town soon, the river is overflowing, so the water level of the river is equal to that in the streets. It wouldn't be so bad except for all the sewage...

Though the flooding has caused some damage to the culverts, nothing to the main embankment, more in depth information to come. Below are some pictures that Bunheng/Chai took last night. We'll be going to the field tomorrow, and we're preparing ourselves to swim through lots of mud.

Maybe I should join the bandwagon-- and move to Cambodia

2009-09-25T05:58:00.008-04:00

So it's day two for me in Cambodia, and it's been great, minus the countless bug bites, falls and near death experiences involving biking around town-- drivers are scary here. I saw a tuk crash into a food cart, there were bowls flying everywhere.

But on other news, HT has a new office, it's across the river. Which is pretty awesome, it's a house... with a pool.

I also got to go to the site today for the first time with Chai. Let me say, pictures don't do it justice. I don't think it really hits you how much this project has helped people till you see all the homes being serviced through this reservoir. But, we drove around the embankment and saw the trees that were planted during the 'tree planting ceremony', collected measurements at the monitoring wells, and took lots of pictures. Other things we checked out was The Vetiver Nursery that will be underway in the next day or two, because everyone had the week off for the recent holidays. And the bamboo is also ready to be used as a 'fence' to keep the fish from getting out of the reservoir.

Lunch with Maria and Bryse.

Passing the Umbrella...ella...ella!

2009-09-21T12:00:00.004-04:00

Drumroll please! It is with great pleasure that I announce the newest Cambodia Project Team member to join the ranks of Project Lead.... Matt Bussmann!

Yes folks, the time has come again to pass the proverbial torch on to the next Team Lead. Only this time we're passing... an umbrella? Why the umbrella, you may ask? Firstly, the neighborhood establishment where many team meetings are held wasn't too excited about our idea of bringing a lit torch inside for the photo-opportunity. Secondly (and more truthfully) it happened to be raining that day.

In all seriousness, an umbrella was a great item to use for this occasion, handing off Project Lead to our veteran team member, Matt. In Oriental tradition, the umbrella symbolizes a shield of protection over the bearer from inclement weather and the hottest heat from the sun. The next few months are a time of transition for the Cambodia Project on a large scale. Farmer Water User Communities (management groups) are in the process of being formed, and the Baseline Assessment will kick off in the months of October - December. In early 2010, HT will start transfering the dam operations and maintenance over to the farmer management communities. In this time of transition within the project team and the project, I hope that the umbrella will live up to its symbolic status. And, for all those familiar with Cambodia, a little shade from the sun is never a bad thing :)

Good luck to Matt and our team in the coming months!

Vetiver: At Home

2009-09-02T10:53:00.004-04:00

Santa Barbara, California

The use of vetiver grass is most common in tropical countries, however there are case studies of its use in California and the US Gulf states as a slope stabilizer. Its use in California's Santa Barbara foothills has been mainly to stabilize slopes in areas highly prone to wildfire. Vetiver typically survives wildfires and has a quick regrowth time after a fire (3 weeks in some cases), making it ideal vegetation to reduce erosion, stabilize steep slopes, and to prevent the subsequent mudslides that typically follow on slopes stripped by wildfire.

Although its use is not widespread in the US, this could be a cost efficient, environmentally friendly method to help reduce the impact of natural disasters on community members in hurricane and wildfire regions.

To read more, check out www.vetiver.org. (Source of picture: www.vetiver.org)

Vetiver... finally

2009-08-27T23:51:00.003-04:00

Chai and the tillers

With the help of Bun Heng, Tobias and the Office of the Royal Development Projects Board in Bangkok, HT has recently procured the long awaited vetiver tillers. Three thousand tillers were delivered in all and now we will need to propagate and plant to stabilize our embankment.

Meeting the Minister

2009-08-16T22:02:00.005-04:00

There were quite a few high ranking officials at the fishery ceremony last month including the Deputy Governor of Siem Reap and the Minister of Forestry.

Here is a photo of Tobias Rose-Stockwell, the Human Translation director, chatting with the Minister of Agriculture, Fishery & Forestry, H.E. Chan Sarun during the ceremony.

Trav Kod Watergate Presentation: India 2010!

2009-08-12T08:38:00.006-04:00

Earlier this summer, the EWB team was selected by the Environmental & Water Resources Institute, a branch of the ASCE, to present the Trav Kod Watergate Project at their 3rd Annual Developing Nations Conference, this coming January in Chennai, India! The full title of this conference is: An International Perspective on Current & Future State of Water Resources & the Environment. EWB's responsibilities consist of submitting a technical paper detailing community relationships, project history and development, design, and construction, and developing an oral presentation, which will be delivered at the conference in Chennai over a few days in January.

The conference consists of projects centered around water and environmental issues throughout Asia and Africa. Project presentations will focus on the global effect of the regional issues confronted in these projects, and the innovative solutions implemented as a result. EWB is proud to share the story of the Trav Kod project on behalf of HT, HRND, the Balang Commune, and all of our partners, in such a conference!

Check out the conference website for more details: http://content.asce.org/conferences/india2010/index.html

Tuk Thom Thom

2009-08-05T23:15:00.002-04:00

HT was just able to obtain this photo from a company that flew by the site taking photos. Pretty nice!

Fishery Ceremony

2009-07-15T03:16:00.005-04:00

This morning, the Ministry of Agriculture, Forestry and Fisheries held a ceremony at Trav Kod to celebrate the reintroduction of fish at the reservoir. Several high ranking Provincial Government Officials gave speeches focused on responsible fishing methods amongst the villagers.

At the end of the ceremony several hundred fish were released into the reservoir, with several thousand more to be provided by the Ministry in the next month.

Roadway and Canal Update

2009-06-30T01:23:00.004-04:00

Over the past few weeks, the Military has been working on the laterite roadway. The have completed compaction and will begin grading shortly. Laterite is well known in Asia and is commonly used for tertiary and sub-tertiary roadways in Cambodia.

The two south canals are also in place. We are still working on rip rapping, which we plan to finish in the next couple of days.

His Holiness

2009-06-30T00:42:00.003-04:00

Congrats to Tobias on this most honored recognition. Don't know if it can get any better than this. Then again, knowing Tobias, it always can.

"...Tobias receives a ceremonial scarf from His Holiness, the Dalai Lama in a ceremony celebrating the humanitarian works of ordinary individuals. This ceremony was called "Unsung Heroes of Compassion." Photo is by Robert Bengtson, who was the official photographer at this event..." -Maria Jarina

New Sign at Site

2009-05-04T11:55:00.003-04:00

Chai just sent this photo of the sign at the watergate. EWB-NY is famous!

Culvert Installation

2009-04-12T19:52:00.004-04:00

Construction is well underway on a series of culverts leading out of the reservoir through the south embankment. The culverts are intended to act as emergency spillways, as well as outlets to provide water to the downstream villagers (replacing the Wat Trach canals that previously occupied the same location). Once installed and backfilled, the culverts will ensure that the roadway on top of the south embankment will remain in service throughout the year. In the past, any flow through these canals during the rainy season meant that the roadway was flooded, and therefore very difficult or even impossible to use.

The design phase consisted mostly of hydrological modeling and re-modeling, trying to optimize capacity of the culverts while minimizing the cost of installation. The crucial number that the team was trying to optimize was the invert elevation of the culverts. Our objective was to minimize the amount of excavation needed to make grade for the culvert installation.

In the end, the hydro analysis showed that six culverts, 1m in diameter, with a slope of 2%, would provide enough capacity to act as the additional emergency spillways for the reservior. To determine the invert elevation for the culverts, we checked many different scenarios in the stage/storage model for the reservior. The few scenarios that met all necessary hydrological criteria were compared with the existing site elevations, and a final decision was made in line with the original objective of minimizing excavation.

The structural details were determined for the sub-base stone layer, concrete collar wall (to aid in preventing water seepage along the length of the culverts), and backfill. Design sketches were sent over to Cambodia in the beginning of March, and construction promptly started. Readily available pre-cast concrete culvert sections, 1m in length, are the typical materials used for culvert installation throughout this region of Cambodia. In the above photo, sections of culvert are being set, and the concrete collar wall has been cast, visible in the background.

Let's hear it for Bernard Amadei!!

2009-04-01T18:47:00.005-04:00

Pick up a copy of ENR, or visit ENR.com this week, and check out the cover story. The founder of EWB-USA, Bernard Amadei, was named the 2008 Award of Excellence winner! This award is one of the construction industry's most prestigous honors, and has been given out annually by ENR since the mid-1960s.

The 7-page magazine article tells the story of Amadei's vision for the future of engineers to use their skills to provide to benefit a larger, more universal purpose. EWB-USA, with its roots starting back in 2002 at Colorado University as a single chapter with a few student members and a small volunteer staff, has grown into a respected, vibrant, nationwide organization with 12,000 members and nearly 300 student and professional chapters.

The article is full of interesting information: descriptions of projects currently ongoing across the world, accolades from industry professionals about the importance of EWB, and innovative ideas in practice today that are "taking EWB from charity to enterprise".

ENR does a wonderful job of communicating the mission, excitement, and passion surrounding EWB. I'd like to congratulate Mr. Amadei for this recognition, and thanks to ENR for the spotlight in one of our industry's most respected publications.

Featured....

2009-03-29T09:49:00.004-04:00

Since the milestone completion of the watergate, this project has been recognized for its tremendous efforts. Our NYC chapter was recently featured by Nationals for this dam project.

Meetings and Vetiver...

2009-03-27T04:06:00.004-04:00

Meeting at military site

These past few weeks have been focused on meetings with the Military, District leaders, Commune leaders, and village leaders. Last week was the first meeting where all were able to meet at one place. Our main topic of discussion was the canal construction which was due to begin yesterday, however, due to malfunctioning equipment is delayed till tomorrow. Also discussed was the erosion control measures for the embankment as well as the proposed laterite roadway.

Dr. Paul Truong of the Vetiver Network
(photo credit: www.hydromulch.co.za/vetiver-grass.htm)

Tobias recently took a trip to Bangkok to inquire about Vetiver grass, which we hope to use along the embankment. A tropical grass that grows locally has many uses from slope stabilization to prevention and treatment of contaminated water and land. This grass with its amazing root structure could be the answer to our erosion issues. We were given some samples to test out for ourselves.

Award-Winning Poster in Denver!

2009-03-11T10:33:00.007-04:00

More accolades for this landmark project are in order for being presented on February 27, 2009 in Denver at Kleinfelder's 23rd Professional Development and Technical Training Seminar during the poster session. With the help of the intricately-crafted watergate model created by Hank Dombrowski and miniatures sculpted by Noa Bornstein, over 1,500 seminar attendees were exposed to our little project half-way round the globe.

And best of all, the poster won the award for "Best Poster Presentation" out of a total of 41 other presentations.

Other EWB NY Project Blogs!

2009-02-19T22:03:00.002-05:00

OK, so we know you've enjoyed following the Cambodia Dam Project's progress on this blog... And we also know you've been craving more EWB-NY project action! That's why we've added links to four other EWB-NY active projects: the Usalama Project, a school expansion and so much more, in Usalama Kenya; the Matunda Health Center Water Project, located in Lugari Kenya; the Belen Clinic Project in northeastern Peru; and the Miraflores Public Health Project located in El Salvador. The links can be found in the "Project Related Links" section of this blog.

Thanks as always for keeping up with our progress, and we hope you'll check out the efforts of our other project teams!!