US Army Corps of Engineers
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Rio Grande de Manati PR (Ciales) Feasibility Study (I)

March 2019


Rio Grande de Manati PR (Ciales) Feasibility Study (I)

Investigation (I)

Congressional Districts: Puerto Rico



The Municipality of Ciales, with population of 18,800, is located on the northern slopes of the Central Mountain Range of Puerto Rico, approximately 40 kilometers (25 miles) southwest of San Juan. The detailed study area is located at the northeast corner of the municipality and within its urban center with population of 2,600. Only the Dos Rios low income housing community (140 units), some commercial structures and the Municipal Sports Facilities are affected by floods at the confluence of Rio Grande de Manati and Rio Cialitos. There are two bridges, one over each river, within the detailed study area. The Rio Grande de Manati at Ciales has an approximate drainage area of 331 square kilometers (128 square miles) and flows north just east of the Dos Rios community. The Rio Cialitos has an approximate drainage area of 44 square kilometers (17 square miles) and flows northeast just south of the Dos Rios Community. Damages associated with flooding have been reported by the Municipality at least four times in the last thirty years.  Among the most damaging, the flood caused by passage hurricanes Hugo (1989), Hortense (1996), Georges (1998) and Maria (2017). In 1985, the Dos Rios community was flooded twice. In addition to damages to property, a serious risk exists to the lives and wellbeing of those residing within the flood plain. The socio-economic development of the community is also seriously impeded by frequent flooding. Previous Flood Damages Reduction studies by the local Sponsor resulted in developing a complete set of Plans and Specifications for the construction of a combination of levees, floodwalls, interior drainage facilities, and channel improvements. In 2010, the estimated construction cost of this project was $8.5 M and because of Puerto Rico’s financial crisis funding for construction was never obtained.




a. P.L. 115-123: Bi-Partisan Budget Act of 2018, Supplemental:

Current Working Estimate $1,200,000
Allocation thru FY18 $0
Allocation for FY19 $0


                          Puerto Rico Department of Natural and Environmental Resources
                          P.O. Box 9066600
                          Puerta de Tierra
                          San Juan, Puerto Rico 00906-6600



The study is brokered to the Great Lakes and Ohio River Division (LRD).The Pittsburg District Project Delivery Team (PDT) held the Alternatives Milestone Meeting (AMM) on 24 Mar-2019. The next major milestone is the Tentatively Selected Plan scheduled for 29 Nov-2019. The Chief of Engineers’ report is scheduled for 09 Oct-2020. Prior to the AMM, FEMA and the PR Public Housing Authority informed the USACE of their decision to relocate the Dos Rios and Alturas de Ciales public housing in order to reduce flood risk of those living there. This will reduce the level or risk in the community and it will also change how USACE address the remaining risk, because part of the problem has already been addressed. Potential alternative will include non-structural alternatives such as relocations.