GIS-BASED COASTAL FLOODING MAPPING FOR PUERTO RICO

(Project Number R-123-1-00)

submitted to Sea Grant Program

University of Puerto Rico

Mayaguez, P.R.

by

Aurelio Mercado Irizarry Professor and

Harry Justiniano GIS

Specialist

Laboratory of Physical Oceanography

Department of Marine Sciences

University of Puerto Rico

Mayaguez, P.R.

May 2006

SCOPE OF WORK

Acquire all coastal floods mapping information available for Puerto Rico, transform it into GIS shape files layers, and make it available through the Internet.

METHODOLOGY

Whatever information is already available as shape files was obtained and used as it is. Whatever information is only available in hard copy format was obtained, digitized and transformed to shape files. These shape files were overlaid over recent aerial photos obtained for the Centro de Recaudación de Ingresos Municipales (CRIM), and supplied to us by the Puerto Rico Management and Budget Office (OGP).

DATA SOURCES

Tsunamis:

Tsunami flooding shape files were obtained from A. Mercado and H. Justiniano as a result of the tsunami flood study done during the Puerto Rico Tsunami Warning and Mitigation Program (http://poseidon.uprm.edu). These shape files show the inland limit of the potential tsunami flooding.

100-Year Coastal Flooding Event (FEMA Flood Insurance Rate Maps):

These shape files are the same ones available through the Puerto Rico Planning Board, and many other state and federal agencies. In this case the flooding zones are classified as Zone 1M (corresponding to FEMA’s Zone V – high velocity zone due to wave action), Zone 1 (corresponding to FEMA’s Zone A: Floodway – high velocity zone due to riverine flow), Zone 2 (corresponding to FEMA’s Zone A – flooding by low velocity water, either by storm surge or river). It is important to understand that with the exception of Zone 1M, there is no way to discriminate between flooding by the storm surge versus flooding by rivers, unless there is no river in the locality, in which case the shown coastal flooding has to be due to the storm surge.

Category 1, 3, and 5 Storm Surges (Hurricane Evacuation Maps, or Storm Tide Atlas for PR):

The early maps made for hurricane evacuation maps, covering Ponce eastward up to Levittown on the north coast, were made only in hard copy. Unfortunately, from about Santa Isabel eastward up to approximately Maunabo, no copy of these paper maps has been found. The same happens with a small coastal section between Guanica and Tallaboa. We inquired with the Puerto Rico State Emergency Management Agency, with the US Army Corps of Engineers, with FEMA, and with the National Weather Service, to no avail. The disappearance of the maps in these south coast locations is shocking since it is right along the south and east coasts that the maximum storm surges are expected.

The available maps were scanned, georeferenced, and manually digitized in order to obtain the shape files showing the inland penetration of Cat 1, 3, and 5 storm surges. For the San Juan metropolitan area two maps were automatically digitized by the USGS at San Juan, P.R. From Dorado westward, all the way down to just eastward of La Parguera, shape files were made available through the Corps of Engineers.

1960’s Wave Swash Data:

This data was obtained by a USGS survey of the inland penetration of wave swash due to a series of northeasterns in the 1960’s. A series of paper maps accompanying the report by Fields and Jordan (1972, F. K. Fields and D. G. Jordan, “Storm-wave Swash Along the North Coast of Puerto Rico: Hydrologic Investigations. Atlas HA-430, USGS) were manually digitized, and the data converted to shape files. This data is only available between the municipalities of Hatillo and Loiza.

1988 Hurricane Hugo Point Values of Debris Line:

After the passage of Hurricane Hugo over the northeastern part of the Puerto Rico the USGS did a survey to measure the location and elevation of the debris line at certain locations of Puerto Rico and island municipalities. The data consists of just point values, and these were included, with the relevant information, in the final maps.

CONCLUSION

An Internet page was created where all of the maps can be downloaded. Its address is http://coastalhazards.uprm.edu. The maps have also been distributed in CD format. They have been widely shown through the local press and TV programs. And these maps have been presented in public hearings all over the island and have been shown to be a very useful tool for land use management.

A CD with the maps is accompanying this report.

ACKNOWLEDGMENTS

We would like to acknowledge the Sea Grant Program of the University of Puerto Rico for the support of this project.