Abstract
The north coast karst belt of Puerto Rico is well known for its conical shaped, limestone hills (mogotes), the Río Camuy cave system, the Arecibo Observatory (now defunct) where a large reflecting antenna is situated in a large (but modified) sinkhole, and hundreds or thousands of other caves. The two main aquifers associated with the north coast karst belt of Puerto Rico provide water for industry, agriculture, municipalities, and domestic uses. Tertiary-age geologic formations associated with both aquifers consist largely of limestone. Significant karst features such as mogotes and sinkholes are common where these units are exposed at the surface. The surface and subsurface geologic units within the north coast karst belt consist largely of Oligocene to Miocene-age sedimentary formations overlain by semiconsolidated to unconsolidated Quaternary deposits. The principal karst forming geologic units associated with the confined (lower) aquifer in the study area are the Oligocene-age Lares Limestone and the overlying Cibao Formation. The Lares sits conformably on the San Sebastián Formation which consists of sandy limestone and consolidated and unconsolidated sand. A marly unit in the upper section of the Cibao provides confinement between the confined and the unconfined (upper) aquifers. The unconfined aquifer consists of the Aguada and Aymamón Limestones. This study focuses on three sites where water recharges the confined aquifer: Cabachuelas Cave Preserve in the municipality of Morovis, the municipality of Vega Alta, and the municipality of Toa Alta. This study shows that the outcrop area of the Lares and Cibao formations is a significant source of water to the confined aquifer to the north that is used extensively by industry, agriculture, and municipalities. A better understanding of this water source could lead to better protections for water quality and could avoid the contamination by industrial activities of the unconfined aquifer.
DOI
https://doi.org/10.5038/9781967518012.1027
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Stratigraphic Controls on Recharge to the Confined Aquifer of the North Coast Karst Belt of Puerto Rico
The north coast karst belt of Puerto Rico is well known for its conical shaped, limestone hills (mogotes), the Río Camuy cave system, the Arecibo Observatory (now defunct) where a large reflecting antenna is situated in a large (but modified) sinkhole, and hundreds or thousands of other caves. The two main aquifers associated with the north coast karst belt of Puerto Rico provide water for industry, agriculture, municipalities, and domestic uses. Tertiary-age geologic formations associated with both aquifers consist largely of limestone. Significant karst features such as mogotes and sinkholes are common where these units are exposed at the surface. The surface and subsurface geologic units within the north coast karst belt consist largely of Oligocene to Miocene-age sedimentary formations overlain by semiconsolidated to unconsolidated Quaternary deposits. The principal karst forming geologic units associated with the confined (lower) aquifer in the study area are the Oligocene-age Lares Limestone and the overlying Cibao Formation. The Lares sits conformably on the San Sebastián Formation which consists of sandy limestone and consolidated and unconsolidated sand. A marly unit in the upper section of the Cibao provides confinement between the confined and the unconfined (upper) aquifers. The unconfined aquifer consists of the Aguada and Aymamón Limestones. This study focuses on three sites where water recharges the confined aquifer: Cabachuelas Cave Preserve in the municipality of Morovis, the municipality of Vega Alta, and the municipality of Toa Alta. This study shows that the outcrop area of the Lares and Cibao formations is a significant source of water to the confined aquifer to the north that is used extensively by industry, agriculture, and municipalities. A better understanding of this water source could lead to better protections for water quality and could avoid the contamination by industrial activities of the unconfined aquifer.