Flooding in Haiti
Summary: Fritz Pierre-Louis's study of flooding in Haiti, dated October 2004 and printed on 13 October 2004, written in the year of the Fond Verrettes, Mapou and Gonaïves disasters. It classifies Haitian floods into six types, from spontaneous lavalas events to the exceptional floods it attributes to the sudden massive release of water accumulated inside limestone massifs, explains karstification as the mechanism, and then turns to the environment, reforestation and the specific exposure of Port-au-Prince, which it locates on a faulted graben with no defense to the south against the northern edge of the Massif de la Selle.
Key Findings
- The classification is the contribution. The study distinguishes six types of flooding in Haiti: spontaneous floods known as lavalas; minor floods without great damage; moderate floods with some material damage to fields and livestock; major floods; exceptional floods, for which it names Jacmel, Fond Verrettes, Mapou and Gonaïves; and special floods described as in situ.
- The mechanism proposed for the exceptional floods is not surface runoff but storage and release. The study describes them as a brutal and massive restitution of water accumulated inside the mountain, where a thread of rainwater acts as a siphon through karstified limestone. That reading matters because it implies a flood can arrive where no river is visible.
- Port-au-Prince is described as structurally undefended on one side. The Cul-de-Sac plain separates the city from the Matheux chain to the north, but to the south it faces the mountains forming the northern edge of the Massif de la Selle directly, and the city sits on a graben, a stepped succession of hills running from Furcy into the middle of the Gulf of La Gonâve, whose rock was crushed by faulting in every direction, which the author gives as the origin of the La Boule sand.
- A specific corridor is named as the most exposed and most vulnerable part of the metropolitan area: the stretch between First Avenue in Bolosse and Mariani. The study also warns that landslides accompanying exceptional floods can occur along the whole northern border of the Massif de la Selle from the Sanatorium hill to Gressier by way of Martissant, Bizoton, Mahotière, Carrefour and Mariani, with the threat sharpened by anarchic construction on the slopes of Morne l'Hôpital.
- The warning signs are already visible on the road network: at every serious rain, National Road No. 2, Avenue Christophe and Bas-peu-de-Chose become impassable under 40 to 60 centimeters of muddy water carrying deposited alluvium, and the southern road between the Cité de l'Exposition and Gressier is exposed on a narrow strip of land between sea and mountain.
- On deforestation the study makes an unusual argument: charcoal is not the biggest consumer of wood, industry is. It asks factories, guildives, bakeries and dry cleaners to switch rather than charcoal users, notes that most charcoal producers work in arid zones such as the Nord-Ouest, La Gonâve, Ganthier and Fond Parisien, and proposes exploiting the Maissade lignite deposit for briquettes for those large consumers. It also insists that any ban on a material must come with a replacement.
- The recommendations are practical and mostly labor-intensive: dredging river beds and drainage canals, terracing torrent beds, a formal ban on building in ravines or near uncanalized rivers, masonry channels near towns and villages, and systematic reforestation with species designated by the Ministry of Agriculture, with vetiver, lemongrass, eucalyptus and above all bamboo named. The author frames this as high-labor-intensity work and therefore as a start on unemployment.
- A record correction: this document was catalogued with 2008 in its title and year field. The text is dated October 2004 and states it was printed on 13 October 2004, and the exceptional floods it cites are the 2004 events, so the record has been corrected to 2004.
How to cite
National Laboratory for Buildings and Public Works (LNBTP), 2004, Flooding in Haiti, https://lnbtp.gouv.ht/publications/inondations.pdf