Our team has finished the pipeline design and is ready to submit to EWB USA for a review of the design work.
To recapitulate, there are five water supply sources within El Negrito, which are listed below. The numbers in parentheses represent the approximate number of houses served by each water source:
1. Pico Pijol (620)
2. La Tutumba / Pate (350)
3. Santa Elena (200 for Santa Elena and Pita)
4. Pita (see above)
5. El Dorado (150)
Each source delivers water to a tank, which then has a distribution system serving various houses in El Negrito. Each household has an average of 7 residents. The Pijol line, constructed in 1994, serves 4 communities (Barrio Abajo, Barrio Arriba, Barrio Meseta, and Barrio Centro) comprising about 4000 of the town’s 10000 residents. It was constructed using PVC pipe for most of the route and a surface run galvanized iron pipe for the section near the source intake in the Pijol Mountains. The pipeline is approximately 15-20 km long and ends in a 41,000 gallon tank. Currently the tank is undersized for the water it receives from the pipeline, and regularly overflows. The pipeline leaks in various places along its route leading to a loss in flow. It was reported that the tank does not have an adequate amount of water to serve the residents. The water received by residents is reported to be polluted as well.
The Pico Pijol source is located southeast of the town of El Negrito. This site is currently the most reliable water source for the population of El Negrito. The pipeline that conveys water to the Town is divided into different reaches
The intake component of the project is located high in the hills above the town of El Negrito. The route of the water supply pipeline traverses very rugged and wooded terrain before entering the town. The 3km pipeline, now forming the scope of the project, is located at the highest reaches of the project and the construction physical constraints are defined by the parameters as noted.
These constraints and pipeline size dictate that construction of a roadway as a materials supply route is not economically feasible. As discussed in the pre assessment trip, the fontaneros (maintenance helpers), very familiar with the terrain, would be prime leaders in the construction, supervising laborers taken from the township. All materials, pipe, valves, and imported fill would be taken as far as vehicles can go, wherefrom they would be carried to the installation locations by hand or domestic animals. Excavation, pipe laying, filling and backfill will be undertaken by local laborers.
EWB/SCFL recommends that the construction begin at the commencement of the dry season to gain as much non rainy hours per day. Hand construction is very slow. There is a high unemployment rate in that township. Given these two factors, EWB/SCFL would suggest that at least two crews work at opposite ends of the line, and towards each other should be employed. This means however that the route location should be carefully marked before hand and carefully monitored as work progresses.
Given this scenario, it is expected that construction should be about 40 meters per day therefore having a schedule of seventy-five (75) working days.
EWB/SCFL will visit the site two times during the construction which will be coordinated with the Mayor.
The material chosen for this project i.e. PVC pipe was specifically selected due to the ease of availability and the fact that no maintenance is needed for the below-ground portion. The fontaneros will be properly trained during the installation of the system so that they can perform maintenance, if needed, on the portion of the system that is aboveground.
The proposed system is similar to the existing water supply system which the fontaneros are intimately familiar with.
Currently the team estimates the cost of the material of construction to be around $76,000.
Based on the first field assessment trip to El Negrito, it is concluded that the EWB Central-South Florida Chapter has the technical resources to provide technical support to deliver a sustainable solution to increase the capacity of the raw water line. Increasing the storage capacity from 41,000 gallons to 150,000 gallons requires more information from the mayor (e.g. confirmation of new tank location, land availability and topographical survey). The EWB SCFL Chapter may be able to support in the following areas:
- Providing technical support to design the needed upgrade of the pipeline and ground storage tank (150,000 gallons)
- Preparation and development of a water Master Plan for El Negrito
The EWB SCFL Chapter considers it feasible to continue with the El Negrito project. Further discussions with the Mayor need to take place in order to define and agree on the scope of work for the EWB SCFL Chapter. A conference call between the Mayor and the team should be scheduled in early February 2011 to discuss and agree on the scope of EWB’s services.