Carrefour River: A Case of Urban Watershed Management in Haiti

Carrefour River A CASE OF URBAN WATERSHED MANAGEMENT IN HAITI Talal Saint-Lôt April 2011 TABLE OF CONTENTS INTRODUCTION FLOOD VULNERABILITY ASSESSMENT CUL-DE-SAC WATERSHED CARREFOUR SUB-WATERSHED UNIT PROBLEM IDENTIFICATION RECOMMENDATIONS CONCLUSION CRP 527 Watershed Management FINAL PROJECT INTRODUCTION Watershed management in Haiti occurs at the community-level in an informal and often, unorganized fashion; especially in the case of its urban watersheds. There are 54 delineated watersheds in the entire country including 158 rivers. Since the interior of the island is mostly mountainous along the north and south peninsulas, rivers are short and fast-flowing from ridge to eef. The atio ’s f esh ate s ste is suppo ted lakes, o e la ge po d, a d s all ponds. Haiti has an estimated source of 14 cubic kilometers, or 11,350,000 acre feet, in freshwater and uses about 1 cubic km per year of which 95% is applied toward agriculture. Water use per capita is 116 cubic meters/year or 84 gallons/day. In a tropical climate like Haiti’s, la k of ate is ot a issue, i stead the a u da e of ate has ee problematic. Haiti receives an average of 40 billion cubic meters, or 32.5 million acre feet, of precipitation per year. Although the country has ample water supplies it suffers from a potable water crisis due to unsustainable management, unequal distribution, and low supply levels.1 This paper focuses on a sub-watershed within a major watershed that is home to almost onethird of the ou t ’s population. The watershed area is characterized by being highly vulnerable to flooding during heavy rains, particularly during the hurricane season. The objective of this paper is to formulate policy recommendations that will assist in reducing population vulnerability to flooding and improve/maintain the health of the watershed. The following sections will cover the reasons for choosing this particular watershed, an assessment of the selected sub-watershed, identification of problem causes, and recommended methods for addressing these problems. 1 Geology and Geography of Haiti CRP 527 Watershed Management FINAL PROJECT FLOOD VULNERABILITY ASSESSMENT Haiti’s la gest ities ha e de eloped alo g the , k oastli e fo the ost pa t. Scarcely vegetated hillsides and absent storm water drainage systems in these cities have allowed serious flood damage during heavy rainfall events. In addition, the trend of uncontrolled housing construction to accommodate rapidly increasing populations has resulted in a large number of dwellings built on flood plains. Considering these facts, population vulnerability to floods has become a primary concern when addressing watershed management in Haiti. In September 2004 colossal flooding damage and loss of life in northern Haiti caused by Hurricane Jeannie spurred international interest in the connection between deforestation and flooding. The World Bank (WB) and Inter-American Development Bank developed a set of priority watersheds in Haiti that were selected based on their importance as areas vulnerable to flooding and the loss of human life and property, in addition to areas with significant opportunities for economic development. Smith & Hersey (2008) performed a GIS-based analysis of watershed vulnerability to flooding in Haiti by evaluating erosion risk, soil potential, population vulnerability, habitat density, and productive infrastructure vulnerability. The findings of this study pointed to the Cul-de-Sac watershed as having the highest ranking in population vulnerability (3 times that of the second place watershed), irrigation vulnerability, and road vulnerability. Further, Smith & Hersey (2008) produced a 3D map using the ArcGIS Hydro model that shows the most likely high flood risk zones of the Riviere Grise sub-watershed within Port-au-Prince. Smith & Hersey (2008) concluded that considering the sheer population density of settlements on the flood plains, in the event of extreme flood, the loss of life and infrastructure damage would be catastrophic. Port-au-P i e, the fou d, had fo loss of life a d i f ast u tu e if a disast ous flood o u s. 2 fa a d a a the highest pote tial 2 Smith & Hersey CRP 527 Watershed Management FINAL PROJECT CUL-DE-SAC WATERSHED The Cul-de-Sac watershed is located in the Ouest department and covers an area of 1580 km2, or 601 mi2. The shed comprises of more than one-fourth of the entire atio ’s populatio o tai i g ithi it si cities: Port-au-Prince, Carrefour, Delmas, Petion-Ville, Croix-des-Bouquet, and Cite Soleil. With more than enough rain, an average rainfall of 800mm or 33 in. annually, the waterways are prone to severe flooding and extreme sedimentation, especially in low-land cities, Carrefour and Cite-Soleil. o st u tio has est i ted the Extreme population density and anarchic ate shed’s a ility to store and filter water following heavy rains. The probability of colossal floods and loss of human life only increases as time goes on and the population continues to grow. CRP 527 Watershed Management FINAL PROJECT CARREFOUR SUB-WATERSHED UNIT Utilizing a flood plain analysis of Port-au-Prince completed by the US Army Corps of Engineers, a sub-watershed a ea alo g Ca efou ’s i e was selected for analysis. t aditio al tou ist desti atio up u til the Carrefour was a ’s as pa t of the la ge Po t-au-Prince metropolitan area. Today, the city is home to more than 400,000 inhabitants, serving as a bedroom community for those who work in the capital. The site area is comprised of a 100- meter buffer alongside the river bank, stretching 1.25-miles beginning at the Boulevard Jean Jacques Dessalines into the ocean delta. Within the sub-shed estimated change in elevation is 173 ft. with an average slope of 5.4%. The river is the largest river in the Carrefour area despite being suffocated on both sides by encroaching settlements. It serves as the primary canal for storm water drainage and is no longer used for irrigation. Extreme sedimentation and unpredictable flow are obvious signs that hu a settle e ts alo g the i e a d i the uppe ate shed ha e alte ed the i e ’s natural flow. Dense settlements along the banks begin at the foot of the mountains immediately south. About three-quarters of the way down the river widens, and then eventually empties into Caribbean Sea. The estimated population within the site buffer area is between 15,000 to 25,000 Haitians and living in between 4,000 to 5,000 homes. CRP 527 Watershed Management FINAL PROJECT PROBLEM IDENTIFICATION Utilizing Sheng (1986) practical approach method to quick identification of problem areas the sub-watershed was evaluated based on the following categories: Physiographical problems – Steep slopes, heavy rains, excessive run-off, and problem soils Resource use problems – Shifting cultivation, forest destruction, fire, over-grazing, uncontrolled mining, poor road construction End problems – Erosion, sedimentation, flood, water pollution, water shortage Socio-economic problems – Illiteracy, low acceptance of innovation, labor shortages, land tenure, poor infrastructures Physiographical Problems The bank structures of this particular river are extremely steep and prone to erosion, especially in areas where there is a lack of vegetation. No Vegetation Crossing Eroding Banks Excessive run-off caused by the abundance of impervious cover along the banks further the risk of erosion and increasing sedimentation. The river varies in width from 10 meters in the most densely populated bank areas to 40 meters north of the highway where channel widening has occurred. Resource Use Problems Due to unplanned urbanization, the proliferation of impervious surfaces hinders the infiltration of surface water required to recharge the ate shed’s CRP 527 Watershed Management a uife s. FINAL PROJECT Indiscriminate construction of roads and homes further complicates the matter, requiring land grading which increases flashiness, and replacing vegetation which critically diminishes the lands ability to store and absorb water. Extremely dense urban growth has occurred between the Blvd. Jean Jacques Dessalines and Highway #2 crossings. The Center for Watershed Protection warns that impervious cover directly influences streams by dramatically increasing surface runoff during storm events resulting in channel enlargement, increased sedimentation, and an increase in magnitude and frequency of bankfull floods. BEFORE AFTER End Problems Heavy rainfall events lead to peak flow causing bank erosion resulting in extreme sedimentation downstream. End problems at this site include flooding, erosion, and sedimentation; phenomena that are inter-related. Socio-economic Problems In Haiti, the poor in urban areas suffer far more than the rural poor. Those living in flood plains, do so by default, because they cannot afford to live anywhere else. Since river banks are state owned land and the government does not have the capacity to enforce squatting laws most CRP 527 Watershed Management FINAL PROJECT homes are constructed on these banks illegally. As a consequence, the population that is most vulnerable to floods in the study site are also the most socio-economically disadvantaged. FLOOD PLAIN MAP OF SITE CRP 527 Watershed Management FINAL PROJECT RECOMMENDATIONS Haiti finds itself in a great paradox in that the country receives more water than it can ever use, yet it struggles to provide the abundant resource to all of its inhabitants. Weak government institutions, lack of financial resources, and the need for technical expertise are all obstacles that must be overcome in order to address the watershed problems in Haiti. MAJOR STAKE HOLDERS The recommendations of this report basically follow a three level intervention plan that includes: local, national, and international stakeholders. Within the Carrefour sub-watershed, it is extremely important that flood mitigation efforts concentrate on the densely populated urban neighborhoods. Since there are no agricultural users depending on the health of the river, it is recommended that water quality be monitored by government agencies. USAID has funded a 5-year program that goes by the acronym WINNER, watershed initiative for the national environmental resources, which claims to reduce risk to vulnerable populations through innovative flood control work. The Ministry of Agriculture and the Ministry of Public Works should also be included in meetings. PRESERVE GREEN DELTA Over the past decades, land use slowly shifted from agricultural uses to intense urbanization, severely weakening the la d’s a ilit to a so a d filte the ate do st ea . The efo e, a initiative to preserve the current green delta is imperative. This initiative should include beautification efforts, as well as an educational program targeting urban communities educating them on watershed stewardship and its potential benefits. REDUCE IMPERVIOUS COVER Impervious cover creates a snowball effect in the degradation of the watershed, increasing peak flow, erosion, sedimentation and the potential of flooding. The planning of roads need to take into consideration their vicinity to the river and the potentiality of adding polluted run-off into the river system. In particular, Ruelle Cannes-a-Sucre, which travels parallel on the west CRP 527 Watershed Management FINAL PROJECT side of the river, should be assessed for potential areas of run-off escape. Rooftops can be converted to gardens that will retain rainwater, reducing run-off but also cooling the dwelling. FLOOD PRONE PROPERTY BUY-OUT To reduce the critical threat of massive loss of life in the case of an extreme flood event, it is recommended that the government of Haiti implement a property buy-out system for those living in flood prone areas. The socio-economics involved are at the heart of the issue; therefore, this program must not only provide alternative housing but also address other immediate needs such as healthcare and employment. Once the flood zones have been vacated, it is recommended that the government classify this area as protective land. CRP 527 Watershed Management FINAL PROJECT CONCLUSION The Cul-de-Sac watershed contains within it multiple urban sub-watersheds, each with its own specific characteristics and problems. The sub-watershed site area selected for this report does not present the highest risk of flood; however, timely action based on a programmatic response rooted in partnerships with neighborhood groups can shift the course of watershed health and i ease the i e ’s alue fo eside ts li i g ea . Up to now, there has been no precedent in Haiti for successful interventions at the level of whole watersheds; success must first be achieved at localized or pilot scales. CRP 527 Watershed Management FINAL PROJECT REFERENCES Center for Watershed Protection. Basic Concepts in Watershed Planning. 2001. Gauthier, Michelle. Watershed Management: Contribution of Urban and Peri-Urban Forestry. FAO. Hadde , Ro e t Lee. “te e G. Mi so . The Geolog of Haiti: A A Geology, Geography and Earth Science. July 2010. otated Bi liog aph of Haiti’s Ministry of the Environment. Government of Haiti. Integrating the Management of Watersheds and Coastal Areas in Haiti. Haiti National Report. September 2001. Louis, Regine et al. Developing Risk Identification Tool for Port-au-Prince, Haiti. Haiti Project Report. Timyan, Joel C. Criteria for Selecting Priority Watersheds in Haiti. August 2006. Sheng, T.C. 1986. Watershed Management planning: Practical Approaches. In Watershed Conservation for Developing Countries. Colorado State University. pp. 78-84. US Army Corps of Engineers. Port-au-Prince Inundation Analysis. Army Geospatial Center Plans and Operation Directorate. January 2010. US Army Corps of Engineers. Water Resources Assessment of Haiti. 1997. http://www.sam.usace.army.mil/en/wra/Haiti/Haiti%20Water%20Resources%20Assessment%20English .pdf USAID-Winner. 10 Ways that WINNER is Changing Haiti. http://www.usaid.gov/helphaiti/documents/winner_100408.html Versluis, Anna J. We All Live Downstream: Disaster, Land Change, and Reciprocity Within the Haitian Watershed. Dissertation for Clark University. October 2008 CRP 527 Watershed Management FINAL PROJECT