A the beginning of the year, a group of Virginia Tech students opened a footbridge in Ti Peligre, Haiti, located in the cenrtal plateau region. This bridge allows the reisdents access to school, market, medical care, and work when the rainy season hits. Oftentimes in Haiti, people are completely cut off when the rains come due to an inability to cross the river. Either the water is too deep or the current too strong to cross safely.
The VT group, a branch of Bridges To Prosperity, saw the need for a safe way to cross and jumped at the opportunity. Multiple trips were taken to assess, plan, and construct the suspended footbridge. Although the process was delayed by the 2010 earthquake, it was still considered a great success. The people in the Ti Peligre community are so grateful and now use the bridge daily. The group was awarded a $100,000 grant to pursure similar projects in other parts of Haiti. Their plan is now to build 5 bridges in the next 5 years - 1 per year. Here are some links that will take you to more information about what VT has already done:
In nearby Fon Ibo, residents face many of these problems during the rainy season. I have even seen it happen in my time here. Life seems to shut down when it rains. Children don't go to school. Fathers don't go to work. Mothers don't buy or sell goods in the market. And when it rains 6 months out of the year, this can cause grave problems. Because of this, I have chosen to write a formal proposal to have our location included in the VT B2P assessment process with hopes that we will be chosen as a final candidate. I have already been in contact with some of the group's members and will be spending the rest of the month researching, taking pictures, and writing up the proposal. Look for more updates soon!
Road Rant (in two parts)
ReplyDeleteI am in Haiti again for the fifth time, and the third time in the past 13 months. I’m still appalled by the state of the dirt roads out in the countryside. It really isn’t all the difficult to design, build, and maintain a dirt road even with labor based methods. So here, finally, is my road rant, drafted between 2 and 3 am night before last when I woke up and couldn’t get back to sleep. A thought is a terrible thing to mind!
ROADS
The construction and maintenance of dirt roads is based on one simple fact and one simple rule. The fact is “Water runs downhill”. The rule is “Get the water off the road”. All the rest is details.
In order to minimize the damage that water does to a dirt road we need to get the water off the road. In order to do this we either 1) crown the road – build up the center and make the water drain to ditches on both edges, or we 2) pitch the road – slope the road surface toward one side so all water from the road runs to one ditch. Unless a pitched road is along a ridge, an upper ditch will be required to handle water coming from land above the road. A crowned road is generally preferred.
If we allow water to run down the length of the road itself, when it rains, the road will become a riverbed. A riverbed has a meandering course with single or multiple channels. This makes for a bad road with a very irregular surface. With heavy rains such a road surface can experience severe erosion and further degradation.
Ditches
Ditches must be constructed to contain the flow of water off the road and from adjacent land during rains. Since water runs downhill all water from land uphill from the road will flow toward the road. This water must be kept in ditches and not allowed to run down the road. Where there are large amounts of water in ditches, the ditches will need to either 1) be reinforced with concrete or 2) lead to drains to get the water quickly away from the road. The choice between these will depend on the surrounding terrain and the willingness of adjacent landowners to allow drains. In general, drains are preferred as they are generally the less expensive. Ditches and drains must be wide enough and deep enough to handle the flow without excessive erosion. As the speed of flowing water increases, it moves larger objects from silt, to sand, to gravel, to larger stones. We do not want the ditches to continuously deepen themselves as this will eventually undermine the edge of the road. A broad shallow ditch is preferred. Vegetation in ditches is acceptable as long as the edge of the road is maintained so that water can flow off the road into the ditch. Vegetated ditches may require regular cleaning to remove accumulated dirt and plant debris. Dirt can be removed to adjacent land or used to build up the center of a crowned road or high edge of a pitched road. Organic debris should be removed.
Puddles
Puddles in the road should be filled with stones, gravel, and dirt as soon as possible. Puddles only get worse with time. As mud (water and dirt) is splashed out the puddle only gets deeper. Low spots in the road will become puddles or mud holes. These will need to be built up with rocks and dirt to force the water to flow off the road into ditches and drains.
Water crossings.
ReplyDeleteThere are situations where it is necessary to have the water flow from one side of the road to the other in order to get it to a drain. There are several ways this can be done effectively. The first is a culvert – a large pipe that allows the water to flow under the road. A culvert need to be large enough to handle anticipated flow and strong enough to withstand the heaviest vehicles that use the road. Culverts are best made of concrete. Concrete culverts are generally stronger and require less burial depth than metal or plastic culverts. It is possible to build a concrete culvert in place using thin pipe, (or even plastic buckets or barrels with ends removed and arranged end to end) to form the inside of the culvert. Concrete with proper reinforcement is poured under around and over this core to form a culvert. Another possible water crossing is a slot, generally of durable wood or concrete. If very narrow, it can be possible to drive directly over the slot without any cover. A wider slot will require a grating or solid cover. As the slot becomes wider we end up needing what is properly called a bridge. Narrow slots are prone to clogging and must be cleaned often to maintain proper flow. Another possibility is a stone paving or concrete drain across the road. This is a wide shallow “V” that is the surface of the road which allows the water to flow across the road without causing damage. Stones must be of sufficient size to stay in place at maximum flow and need to be carefully laid.
Crossing water
There are situations where the road must cross existing bodies of water such as rivers or even small lakes. This will generally require a bridge. A bridge is a serious undertaking that requires proper engineering.
Riverbed Roads
In some situations, the riverbed is the road, or at least the road repeatedly crosses through the river. Little can be done to improve such a road short of obvious removal and placement of stones to smooth river entries and exits.
For more detailed information on building and maintaining dirt roads see: Earth Roads: Their Construction and Maintenance, Jack Hindson, revised by John Howe and Gordon Hathway. 1983.
A practical manual for non-engineers which describes the design and construction of earth roads with a usage of up to 50 vehicles per day. Covers drainage, road planning, the actual construction, and subsequent maintenance operations.
Related References
Road Maintenance and Regravelling (ROMAR) using Labour-Based Methods Handbook &
Workbook, 1996 Claes Axel Andersson, Andreas Beusch, and Derek Miles
Labour-Based Road Construction: A State-of-the-Art Review
Edited by Paul Larcher, 1998
Roads and Resources:Appropriate Technology in Road Construction in Developing Countries,
G. Edmunds and J. Howe, 1980
Understanding Low-Cost Road Building, David K. Blythe
Outlines planning, equipment, and maintenance requirements for building simple roads.