Vulnerability to Contamination of Karst Aquifers

The karst aquifers are especially vulnerable to pollution due to their hydrologic behavior derived from karstification. The vulnerability mapping is one of the most applied tools to protect them. There are a wide range of methodologies for vulnerability mapping that have been developed for karst aquifer, to consider the specific characteristics of karst into the vulnerability assessment, such as EPIK, PI, COP, Slovene Approach, and PaPRIKa, among others. The vulnerability map can help to the water stakeholder for making decision and to promote a land-use management compatible with the water protection. So the maps should have reliable accuracy. Many works highlight that the maps of groundwater contamination vulnerability obtained by the different methods differ significantly, although they were all obtained by methods developed for karst aquifers, even if they are obtained from the same sources of information and applied by the same person. So, the validation is an essential element of any contamination vulnerability assessment. The current challenge of researchers is to obtain versatile and easy to apply methods to test and validate vulnerability maps

Modeling intrinsic vulnerability of complex karst aquifers: modifying the COP method to account for sinkhole density and fault location

This study investigates a method of karst-aquifer vulnerability modeling that modifies the concentration-overburden-precipitation (COP) method to better account for structural recharge pathways through noncarbonate rocks, and applies advancements in remote-sensing sinkhole identification. Karst aquifers are important resources for human and agricultural needs worldwide, yet they are often highly complex and have high vulnerability to contamination. While many methods of estimating intrinsic vulnerability of karst aquifers have been developed, few methods acknowledge the complication of layered karst aquifer systems, which may include interactions between carbonate and noncarbonate rocks. This paper describes a modified version of the COP method applied to the Kaibab Plateau, Arizona, USA, the primary catchment area supplying springs along the north side of the Grand Canyon. The method involves two models that, together, produce higher resolution and greater differentiation of vulnerability for both the deep and perched aquifers beneath the Kaibab Plateau by replacing the original sinkhole distance parameter with sinkhole density. Analyses indicate that many karst regions would benefit from the methodology developed for this study. Regions with high-resolution elevation data would benefit from the incorporation of sinkhole density data in aquifer vulnerability assessments, and deeper semi-confined karst aquifers would benefit greatly from the consideration of fault location

Anticipating and managing engineering problems in the complex karst environment

Karst environments are characterized by distinctive landforms and a peculiar hydrologic behavior dominated by subsurface drainage. Karst systems can be extremely complex, heterogeneous, and unpredictable due to the wide range of geological and hydrological controlling factors. The great variability results in serious problems for engineers, and in difficulties to characterize the karstified rock masses, and in designing the engineering works to be performed. The design and development of engineering projects in karst environments require specific approaches aimed at minimizing the detrimental effects of hazardous processes and environmental problems. Further, karst aquifers (that provide approximately 20–25 % of the world’s drinking water) are extremely vulnerable to pollution, due to the direct connection between the surface and the subsurface drainage, the rapidity of the water flow in conduit networks, and the very low depuration capability. Sinkholes are the main source of engineering problems in karst environments, and may cause severe damage in any human structure. The strategies and solutions that may be applied to mitigate sinkhole problems are highly variable and largely depend on the kind of engineering structure, the karst setting, and the typology and size of the sinkholes. A sound geological model, properly considering the peculiarities of karst and its interactions with the human environment, is essential for the design of cost-effective and successful risk reduction programs. Due to the unique direct interaction between surface and subsurface environments, and the frequent ground instability problems related to underground karstification, management of karst environments is a very delicate matter. Disregarding such circumstances in land-use planning and development inevitably results in severe problems with high economic impacts. Karst environments require specific investigation methods in order to properly manage and safeguard the sensitive geo-ecosystems and natural resources associated with the