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)).
Upwelling occurs when winds blowing across the ocean surface push water away from an area and subsurface water rises up to replace the diverging surface water. Upwelling occurs in the open ocean and along coastlines. The reverse process, called downwelling, also occurs when wind causes surface water to build up along a coastline. The surface water eventually sinks toward the bottom. Subsurface water that rises to the surface as a result of upwelling is typically colder, rich in nutrients, and biologically productive.