Sinkhole urban areas due to water main breaks or sewer collapses when old pipes give way. They can also occur from the overpumping and extraction of groundwater and subsurface fluids. Sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Some sinkholes form when the land surface is changed, such as when industrial and runoff-storage ponds are created; the substantial weight of the new material can trigger a collapse of the roof of an existing void or cavity in the subsurface, resulting in development of a sinkhole. Sinkholes tend to occur in karst landscapes. Karst
Bayou Corne sinkhole Oxy3 had begun to cave in. Louisiana Governor Bobby Jindal issued an evacuation order on August 3, 2012 after residents reported smells of crude oil throughout the town. Texas Brine investigated the situation by drilling a relief well and found that the outer wall of the salt dome had collapsed, allowing sediment to pour into the cavern and oil and gas to escape to the surface, causing the shaking and bubbles residents had observed. When first the sinkhole appeared, it spanned a hectare (2.5 acres). As of late February 2014, the sinkhole is 26 acres and growing. Texas Brine is