Bridge over the Rio Blanco near the proposed dam site
Yesterday afternoon I received a surprise visit from Miguel Viquez, an Environmental Planner for the new hydroelectric dam proposed for the Rio Savegre named Proyecto Hidroeléctrico Savegre, or PH Savegre.
Part of this project includes a tunnel that will likely run beneath Hills of Portalon, and directly under my lot. The current phase of the planning includes taking core samples at various sites along two possible tunnel routes, and last year ICE indicated they wanted to drill a core on my property but, at that time, were not exactly sure where the drilling rig would be located.
Yesterday, Sr. Viquez arrived with a map showing planned locations of the core drilling sites. Since taking a core sample to a depth of 300 meters takes around three months, I had some questions — one of which was about the noise created by a diesel drilling rig near my house — and Sr. Viquez invited me on a tour to visit an operating drill site.
What started as an unplanned afternoon turned into a pleasant drive up the Rio Savegre, an interesting conversation with Sr. Viquez, and a visit to the dam site. While there I met with Nancy Ramírez Castro, a Geological Engineer who works for ICE on the PH Savegre project, along with other engineers and a drilling rig crew.
Miguel Viguez (center) and Nancy Ramírez (right)
discuss plans to drill a core sample in my yard.
This was not the first time that I had met Sr. Viquez and Sra. Ramírez. Both had attended an ICE community meeting held in Rana Roja last year, where a through overview of the project was presented to those who were interested. It was good to meet with them again in a field setting, and get to know them and their ideas a little better. Both of these people have a lot of enthusiasm for the project, and see it benefiting the local area and Costa Rica in many ways.
After that meeting in July of 2009, as I wrote in some earlier notes before I started this blog: The current investigation phase is due to be completed in 2011 and, if things proceed as planned, funding will be needed from the legislature by 2014. Once funded, machinery and other equipment will be purchased by 2020. After that, construction of the dam, the hydro tunnel, and the electrical generating plant in Pasito will begin.
Stacks and stacks of flat core sample boxes
await transportation to San Jose.
I was impressed by the amount of road, electrical, Internet, and other community development that ICE has undertaken along the route next to the Savegre river, including a large futbol plaza in Silencio and several new bridges along the way.
When I asked about the impact of diverting a six-meter tube of water away from the Savegre river, I was told that during the rainy season the impact would be negligible but that during the dry season there would be a noticeable difference which would probably affect river rafting tours.
I was also reminded that there are a lot of quebradas and other tributaries into the Rio Blanco and Savegre rivers below the dam site, and these will continue to feed the river as they currently do. I guess this will mitigate the impact some, but there will obviously be changes to the ecosystems both above and below the dam.
A box containing various sections of a core sample.
While looking at some of the core samples taken, Sra. Ramírez mentioned that after the samples have been examined, most of them will be disposed of. However, some of them will be retained indefinitely in a warehouse in San Jose.
Next we crossed the Rio Blanco and drove a short way to a core drilling site, which was about half way between the bridge and where the dam will be located.
If anyone has taken a rafting trip down the Savegre River, you likely entered the water at an old bridge on Rio Blanco, about eight kilometers beyond Rifiki Lodge. The old cement and steel bridge is quite distinctive, and if you’ve seen it you will recognize it, but maybe not in the small photo at the top of this article (that photo was taken last summer when I went rafting with some clients).
An ICE drilling rig site overlooking the Rio Blanco (look closely and
you can see the old bridge over the river in the background)
Each drilling site needs around 150 square meters for the rig, a small shelter for the crew, and a separate shelter to protect the emerging core sections from rain and sun.
In addition to the core, other sampling is done at each site. A seismic survey is done using small explosive charges. Just enough explosive is used to obtain a “map” down to the drilling depth, and is similar to geological imaging done at other types of exploration sites such as gas, oil, and paleontological digs.
This drilling rig has caterpillar tracks, while others have an
augur propulsion and some have normal wheels
I was told that they currently have four drilling rigs that will be used. Each rig will spend from one to around three months at each site, and will then be move to the next site. To remain on schedule, all core drilling must be complete by the end of next year.
For very remote or difficult sites, where it is not feasible to construct or improve an access road, a helicopter can be used to transport the rig to a site. One thing that the project engineers wanted me to understand was the emphasis on low environmental impact from the drilling operations.
They pointed out an area where drilling had been done earlier, and emphasized that there were no remaining remnants, other than a small cement cap above the core hole, and the jungle had already grown back over the sites. I did notice a small diesel oil slick near the caterpillar tracks of the drilling machine but, other than this one oversight, the area was obviously well maintained.
The diameter of the core hole is only 7 cm,
but the depth can reach 300 meters
Another thing that is emphasized is safety, both of the ICE employees, and the project. In the shelter I saw an emergency “back board” used for immobilizing and transporting an injured person. Also, Sra. Ramírez mentioned the necessity of access to the drilling sites by emergency vehicles, whether by auto or by air.
The drilling crew works from 6am to 6pm and, at night time, there is a security guard at each site to ensure that nothing is mis-handled or removed. This includes the valuable core samples and other materials used at the site such as the explosive charges I mentioned earlier.
After the site tour, we had lunch at a local ranch house where ICE has contracted with the owner to provide meals for the construction and drilling crews. In talking with the rancher, he indicated that the project is a good one, and he has no objection.
From what I understand, this attitude is not shared by all neighbors in the vicinity of the dam, including the family who runs Rafiki Lodge. Perhaps I will make a trip to visit them and then write about their viewpoint.
References
- Maps of PH Savegre — in three resolutions
- ICE Community Meeting — notes from 23-July-2009
- Hydroelectricity — information from Wikipedia
