The abundance of karst depressions in Yucatán has been widely recognized, but they have not been classified or quantified despite their importance in land-use planning. Our objective was to study the types and areas of the sinkholes, uvalas, and poljes and identify their patterns of spatial distribution. We used 58 topographic maps (1:50,000) from INEGI, from which we extracted the depressions and bodies of water. For typology, we used a circularity index and the shape and area of the depressions. For single-density analysis, we extracted the centroids and added an inventory of karst features (cenotes, caves). We counted 6717 depressions with a total area of 454 km 2 and 750 karst features. We identified 4620 dolines (34 km 2 ), mainly in plateaus below 30 masl. In number, they are followed by uvalas (2021) and poljes (76), occupying together a similar area (210 km 2 ) and dominating in elevations higher than 30 masl. Eighty percent of the dolines were automatically labeled. The density of depressions allowed us to identify the "ring of cenotes" and the "field of dolines" according to two main types of factors, structural and climatic. The typology and density of the depressions could be used as geomorphological differentiation criteria in the vast plateaus of central and eastern parts of the state.
Morphological relief analysis allows the identification of geomorphological forms and cartographic-environmental studies make extensive use of the medium (1:50,000) and large scale (1:250,000), where the topographical contrast is evident. However, at a detailed scale (<1:20,000) and for territories where the contrast of relief does not exceed 10 m in height, the morphological analyses must be adapted accordingly, because they contribute information to altimetry studies and to the topographic configuration of units. Thus, through visual interpretation and manipulation of high-resolution topographical LiDAR data from Cozumel Island, a relief analysis is presented at a detailed scale for the purpose of recognizing the geomorphological units of karst origin, using altimetry and slope cartography, digital models of elevation, and shading that permits the identification of 109 new exokarstic doline and uvala formations.
The Yucatán Peninsula is mainly composed of limestone. Cozumel Island is part of the Yucatec carbonate platform. Dissolution processes in the limestone lead to karstification. Groundwater preferentially flows into karstic cavities. Due to its geological structure the karstic aquifer shows a high vulnerability to anthropogenic impacts. This study investigates the impact on groundwater in the area of the informal settlement "Las Fincas". Due to the informal urbanization of the settlement there is neither a public water and power supply nor a sewerage nor waste disposal system. Groundwater samples were taken in a number of domestic wells that are in use for local water supply in "Las Fincas" and tested for typical indicators of anthropogenic pollution. Distinct evidence of fecal contamination was found. The evaluation of a reference analysis of wells outside "Las Fincas" also showed a significant fecal contamination. Two aspects were considered as a reason for the fecal pollution. On the one hand there is the pollution of wastewater and feces by the local residents. On the other hand, there is the practice of the grouting of treated wastewater in deeper zones of the aquifer by the local water supplier. For further investigation a long-term monitoring was established in order to take groundwater samples and record groundwater levels frequently. The study documents the hydrodynamic and hydro chemical conditions of the aquifer and gives recommendations for the use of groundwater without any health risk.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.