Haiti – Dominican Republic - Disasters and Conflicts - UNEP

6 Freshwater resourcesand flooding6.1 IntroductionThe border zone is moderately well endowed withwater resources. The important permanent rivers(from north to south) include the Massacre, theArtibonite and the Perdenales. In addition thereare multiple rivers and streams that are transientand effectively dry in the dry season (known asarroyos in Spanish). Finally there is Lac Azuei, knownas the Etang Saumâtre in Haiti, which forms theHaiti-Dominican Republic border in the Cul-de-Sac Valley. Lac Azuei is brackish, so although it isan important water feature it is not a fresh waterresource. Despite the amount of available waterresources, shortages can still be severe in particularregions throughout the year and broad scale watershortages are experienced right through the dryseason.Change in the availability of fresh water is alreadya major concern for farmers and communitiesin the central parts on both sides of the borderzone. 253 Water levels have decreased here mainlydue to changes in precipitation and in runoff rates,erosion, as well as sedimentation of canals, whichhave in turn changed the physical characteristicsof the rivers. 254There are two types of transboundary rivers andriver sections in the Haiti-Dominican Republicborder zone:• Riverine borders – where the border is the riveritself, or runs close and parallel to the rivers,as true for the Massacre River, parts of theArtibonite River network, and the PedernalesRiver. In these instances, the ownership andwater allocation rights remain unclear betweenthe two countries.• Border crossing rivers – where one nation isupstream and the other downstream.This distinction is important, both in terms of keyissues and potential solutions. Responsibility forcatchments with riverine borders is shared andsometime blurred. In contrast, the allocation ofresponsibility for border crossing rivers is clear:responsibility and ownership changes at theborder.6.2 Key issuesTransboundary water resources are a subject ofhigh interest in both countries. There are severalserious issues but only limited tensions. In generalmost issues are of mutual interest to be addressedand the potential for cooperation is clear. The mostdifficult issues are linked to floods and borders thatcross rivers, where actions or lack thereof in onecountry directly impacts the other.The four most important issues noted in theassessment were:• Transboundary river flooding.• Water scarcity, access and pollution.• Lake Azuei and Lake Enriquillo flooding.• Transboundary dams and water extraction.6.3 Transboundary floodingThe phenomenon of flash flooding in Hispaniola iswell understood. High rainfall events in the upperparts of degraded catchments result in very rapidrises in river levels. The flood peaks which can lastfrom hours to a few days at most, breach riverbanks and impact settlements in and adjacentto the flood plains. This is a nationwide problem inHaiti and a problem in some specific areas in theDominican Republic.A rarer problem is that of floods caused by hurricanesand tropical storms. In these cases, veryheavy and widespread rainfall – over a period ofhours or even days – simply overwhelms the entirecatchment and widespread flooding occurs allalong the floodplain, with water levels taking upto days to fully recede.Transboundary flooding is a very localized subsetof the larger problem of flooding in Hispaniola. Inselect cases, rainfall in one country causes floodsand damage in the other.The importance of this transboundary issue iscatchment specific. It is not, for example a majorissue for the Massacre watershed, but is an importantissue for the Artibonite watershed, the areasaround the lakes and the Pedernales watershed.However the impact of “normal” heavy rainfall inthe Dominican Republic upon Haiti is mitigatedby remaining forest cover and the Peligre Dam.Haiti – Dominican Republic: Environmental challenges in the border zone71