Hobbies And Interests
Differential Compacting (Settling)
When a building is being constructed, the footer of the foundation is usually formed by pouring concrete into a level trench that outlines the house's perimeter, or across the entire base if there is to be a basement story. The walls are then built upon this footer. The load of the house is then distributed onto the footer through the exterior walls. In normal settling, the weight of the building will somewhat compact the soil. In pinnacle karst, however, a select portion of the footer may be supported only by soil while others are supported by stronger pinnacle karst, creating uneven settling. This uneven settling can cause cracks in the floor, walls and foundation, perhaps dramatically weakening the building's structural integrity. It is important that even residential dwellings include an engineering plan to compensate for differential compaction in areas showing karst topography.
Subsurface Erosion (Piping)
In areas where there has been a significant alteration in ground water levels, either through displacement of natural rainfall, overpumping of ground water or pipe leakages, the soft sedimentary basement layer in karst areas can become eroded. This erosion can create large subsurface cavities, diminishing the structural support for a building's foundations and creating the same engineering problems as seen in cases of differential compacting. Although this is common in areas with karst topography, it can occur in other areas as well. Worryingly, the loss of supporting soil may bot become apparent until a large cavity has developed and significant irreparable damage done. The outcome can be either a slow subsidence of the affected area or a sudden collapse of the affected soil and structure above it.
Collapse Sinkholes
Collapse sinkholes form when the basement rock supporting the soil above it becomes completely dissolved by water. The soil then sits on a subsurface air bubble. Progressive erosion, the weight of absorbed water or the construction of a building above the affected area can cause the bridge of soil above the bubble to collapse completely. These can be minor, foundation damaging subsidences or enormous pits large enough to swallow a small town entirely.
Nonpoint Pollution
The extensive network of waterways beneath the earth's surface is a defining characteristic of karst topography, as it is the presence of those waterways that carve the underground tunnels that create karst. These waterways, however, lack the impermeable boundaries that other aquifers possess, making it easy for contamination to spread quickly and over long distances. An industrial spill over a hundred miles away can easily make its way into a karst aquifer, impacting water quality for the residents of communities relatively far from the site of the spill.