When are Quarterly Estimated Taxes Due? Estimated taxes are due quarterly on specific dates during the year. The IRS mandates that the normal due dates for estimated taxes are April 15 for the first quarter of a year, June 15 for the second quarter, Sept. 15 for the third quarter and Jan.15 of the following year for the fourth quarter.
Salt water intrusion occurs in coastal freshwater aquifers when the different densities of both the saltwater and freshwater allow the ocean water to intrude into the freshwater aquifer.hen this occurs, it will move the saltwater freshwater interface inland, resulting in a higher saline concentration in the aquifers' water, rendering it useless for human consumption, unless it is treated. Figure 4. Saltwater Intrusion Situation(University of Florida, 2000)).
Sea IceSea ice includes frozen sea water, such as that in the Arctic Ocean and the oceans surrounding Antarctica, and frozen lake and river water, which occur mainly in the polar regions. Sea ice is formed by the direct freezing of the water on which it floats. If the water is salty, as it is in the ocean and in seas, during the freezing process the salt is left in the water, making the water more salty and denser and the sea ice less salty. Lake and river ice is frozen from fresh water generally and is therefore, not salty.