page_title: Saltwater intrusion
section_title: Mitigation
hierarchical_section_title: Saltwater intrusion / Mitigation
caption_attribution_description: English: Catfish Point Control Structure, at the outlet of Grand Lake into the Mermentau River, which flows into Vermilion Bay in the Gulf of Mexico. The lock is located in at the east end of Cameron Parish, Louisiana, USA. This lock is a salt water intrusion barrier to prevent the waters from the Gulf of Mexico from intruding into Grand Lake and the freshwater bayous and rivers.
context_page_description: Saltwater intrusion is the movement of saline water into freshwater aquifers, which can lead to groundwater quality degradation, including drinking water sources, and other consequences. Saltwater intrusion can naturally occur in coastal aquifers, owing to the hydraulic connection between groundwater and seawater. Because saline water has a higher mineral content than freshwater, it is denser and has a higher water pressure. As a result, saltwater can push inland beneath the freshwater. Certain human activities, especially groundwater pumping from coastal freshwater wells, have increased saltwater intrusion in many coastal areas. Water extraction drops the level of fresh groundwater, reducing its water pressure and allowing saltwater to flow further inland. Other contributors to saltwater intrusion include navigation channels or agricultural and drainage channels, which provide conduits for saltwater to move inland. Sea level rise could also contribute to saltwater intrusion. Saltwater intrusion can also be worsened by extreme events like hurricane storm surges.
context_section_description: Saltwater  is also an issue where a lock separates saltwater from freshwater (for example the Hiram M. Chittenden Locks in Washington). In this case a collection basin was built from which the saltwater can be pumped back to the sea. Some of the intruding saltwater is also pumped to the fish ladder to make it more attractive to migrating fish.
caption: Catfish Point control structure (lock) on the Mermentau River in coastal Louisiana
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