HAITI’S ROCK AND SOIL ENGINEERING
Haiti has abundant rainfall and streamflow; however, it suffers from serious water supply problems due to wastewater and agricultural pollution of its surface and ground waters, sedimentation of its surface reservoirs from deforestation, seawater intrusion, thin and narrow coastal porous media alluvial aquifers, and low-yield inland fractured rock aquifers (USACE, 1999).
Soil Brief
In general, if loose materials pass the 200-mesh sieve, it’s soil. There are several soil classification systems, depending on its potential use in agriculture, excavation, and construc- tion. Soils may be deposited and transported by wind (aeolian), water (overland river flow) and rock-mass wasting, or devel- oped in-place by chemical, biological, and mechanical rock decomposition over and within bedrock. To the engineer, soil consists of gas and solids, while agriculturalists are interested in organic matter, biological, and chemical properties as well. Haitian soils are derived from igneous, metamorphic, and sedimentary rocks, including its abundant carbonates.
The USDA-NRCS Soil Taxonomy system (1999) is based on 12 soil “orders,” and “suborders.” Haiti’s general surface suborder soils, Aridisols, Utlisols, Alfisols (forest soils), and Inceptisols are the soil orders prevalent in Haiti.
These soils are derived predominantly from calcareous materials with some basaltic material in several areas of the country (Louissant, 2006). Moreover, about 60 percent of all lands have slopes greater than 20 percent. Only 29 percent have slopes less than 10 percent. Interestingly, less than 20 percent of the land under cultivation is appropriate for agri- culture. Haiti produces only 50 percent of the foods for its population. Soil erosion on unterraced mountain and hillside slopes, recurrent drought, and absence of irrigation make crop production paltry. This issue, poor governance, natural hazards, illiteracy, and abject poverty contribute to Haiti’s Human Development Index of 169 of 189.
Maps of the impact of Haiti’s 2010 earthquake show the “extreme” and “violent” areas comprise the most highly densely populated parts of Haiti. Maps of Haiti multi-hazard risk, major disasters and severity (1998-2020) show that the highest risks are associated with earthquake faults and hurricanes.
Potential Solutions tions.
There are several obvious and more subtle potential solu-
Obviously, improvements and enforcement of design, engi- neering, and construction permits, codes, and regulations could be helpful, similar to the U.S. National Environmental Quality Act (NEPA, 1970), US court-ordered 22CFR216 (1976) for Foreign Assistance, and the more stringent California Environmental Quality Act (CEQA, 1970), as well as land-use zoning and use restrictions, similar to California and Oahu, Hawaii restrictions for permanent structures near active faults (Alquist Priolo Special Studies Zone Act, 1972) and tsunami and coastal flooding zones, respectively. Revisions, updates, and distribution of Haiti’s active fault, landslide, liquefaction, flooding, and karstic vulnerability zones and early warning system upgrades would be obviously useful. U.S. tsunami, US National Hurricane Center hurricane, California’s earth- quake, and San Francisco Bay area’s landslide warning sys- tems are good examples of what is feasible.
Uncertainty and Risk Issues
The importance of consultants and practitioners to be cur- rent in technology and litigation cannot be overemphasized.
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Jul.Aug.Sep 2021
The advances in geotextiles provide cheaper and more sus- tainable potential designs and mitigations to engineering soil challenges. As Albert Einstein said, “Once you stop learning, your start dying.”
Uncertainties and risks include: testing or incomplete obser- vations can lead to engineering failure of structures or mitiga- tion measures. These may lead to loss of life and destroyed property and infrastructure.
Observing, drilling, sampling, and testing in the wrong loca- tions, lead to the wrong conclusions, recommendations, and thinking. For example, not observing thin, expansive clays or shales in soils, or solution cavities in rock can be catastrophic. Correct observing is essential. As Yogi Berra said, “You can observe a lot by looking”.
Another risk includes sampling and testing errors, and misunderstanding and misusing testing assumptions. For example, sampling and testing water-flow in solid rock and missing testing of rock fractures, and poorly testing soil pore water content, can be catastrophic. In addition, failure to appreciate that field conditions will change soil reactions over time and higher loads than tested can be catastrophic. My work in Sri Lanka indicated that dozens of accurate in-place permeability tests in limestone produced results similar to concrete and orders of magnitude lower than a half-dozen pond permeability tests which realistically accounted for limestone fractures.
Focusing on average test-results rather than risky-extreme test results can be dangerous.
As Syed (1982) taught me: “Soil engineering is the uncom- fortable nexus, if not conflict, between scientific fact and engineering judgement in managing soils to support physical infrastructure.”
Geological and Soil Engineering
Table 1 on page 17 summarizes common problems, damage, and a potential remedy. These are not intended to replace detailed engineering studies, testing, and analysis. Because of Haiti’s extreme poverty, the cost of well-designed, engineered, and constructed safe structures needs to be heavily subsidized.
Author
Barney Paul Popkin is a geologist, hydrologist, soil scientist, solid waste and hazardous materials manager, teacher and trainer, and water/ wastewater, drainage/ flooding specialist, and monitoring and evaluation specialist with over 50 years experience in about 30 U.S. States and as many developing countries.
Bibliography
Alliance Haïti. 2011. available online, June 2011, http://www.
alliance-haiti.com/societe/
conditionfemme.htm.
Bureau for the Development of Agricultural Production (Bureau pour le Developpement de la Production Agricole, BDPA). 1982. Cartographie thématique d’Haïti. Bureau pour le Developpement de la Production Agricole, Paris & Secretairerie d’Etat du Plan (DATPE), Port-au-Prince. pp. 33-99.
Canadian International Development Agency (CIDA). 1998. Environmental Scarcities and Conflict.
Central Intelligence Agency (CIA), December 29, 2020. World FactBook, Haiti.
CLIMATE-DATA.org, Port-au-Prince climate: Average Temperature, weather by month, Port-au-Prince water tem-
www.aipg.org
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