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.
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.