Where river meets ocean | EurekAlert! Science News
They also are essential to the global economy. They are estuaries — coastal embayments where fresh river water and salty ocean water meet. River waters simply meeting is one thing, but when those bodies of water display distinguishing . The Gulf of Alaska, where two oceans meet, but do not mix!. They also are essential to the global economy. They are estuaries -- coastal embayments where fresh river water and salty ocean water meet.
Roughly once per decade, drought conditions cause the salt intrusion to approach the Poughkeepsie freshwater intake.
Where river meets ocean
The last time this happened, inextra water had to be spilled from dams upstream to keep the salt front from becoming a public health hazard. The lifeblood of estuaries Estuarine circulation serves a valuable, ecological function. The continual bottom flow provides an effective ventilation system, drawing in new oceanic water and expelling brackish water. This circulation system leads to incredible ecological productivity.
Nutrients and dissolved oxygen are continually resupplied from the ocean, and wastes are expelled in the surface waters.
This teeming population of plankton provides a base for diverse and valuable food webs, fueling the growth of some of our most prized fish, birds, and mammals—salmon, striped bass, great blue heron, bald eagles, seals, and otters, to name a few.Black Rock River - Part 2 - Mahlongwa River Breach
The vigor of the circulation depends in part on the supply of river water to push the salt water back. The San Francisco Bay area has become a center of controversy in recent years because there are many interests competing for the fresh water flowing into the Bay—principally agriculture and urban water supplies extending to Southern California. Estuarine circulation is also affected by the tides; stronger tides generally enhance the exchange and improve the ecological function of the system.
The Hudson estuary, for example, is tidal for miles inland to Troy, N. Some are self-inflicted; some are caused by the abuses of human habitation. An estuary, with all of its dynamic stirrings, has one attribute that promotes its own destruction: When suspended mud and solids from a river enter the estuary, they encounter the salt front.
Where British Columbia's Fraser river water meets the Pacific Ocean : interestingasfuck
Unlike fresh water, which rides up and over the saline layer, the sediment falls out of the surface layer into the denser, saltier layer of water moving into the estuary. As it drops, it gets trapped and accumulates on the bottom. Slowly, the estuary grows muddier and muddier, shallower and shallower. Occasionally a major flood will push the salt right out of the estuary, carrying the muddy sediment along with it. Sediment cores in the Hudson River indicate that sediment may accumulate for 10, 20, or even 50 years, laying down layers every year like tree rings.
But then a hurricane or big snowmelt floods the river, wipes out the layers of sediment, and sends the mud out to sea.
It is good because a big storm can keep an estuary from getting too shallow too fast. In fact, it appears that over the last 6, years, the natural dredging by large storms has maintained nearly constant water depth in the Hudson estuary. Environmental regulations are far stricter now than they were 50 years ago, and we have stopped using many chemicals that play havoc with the environment. For instance, polychlorinated biphenyls PCBs were banned in the s because they were shown to be toxic to fish and wildlife, and to the humans who consume them.
11 Incredible Points In The World Where Major Bodies Of Water Join Together
Trickle-down effects Billions of dollars are now being spent to clean up American estuaries contaminated by industrial pollution. The Superfund program of the U. Environmental Protection Agency collects and spends billions of dollars more to remediate estuaries. Often the remediation strategies are complex and controversial.
In the case of Hudson River, there is a heated debate about whether PCB-contaminated sediments should be removed—dredged with high-tech methods that theoretically minimize environmental harm—or left undisturbed. That debate pivots on the episodic storm phenomenon: Are the contaminated sediments there to stay, or could they get stirred up when the next hurricane washes through the Hudson Valley? Aside from cleanup initiatives, parts of the Hudson need to be dredged for navigational purposes.
- Where River Meets Ocean
- 11 Incredible Points In The World Where Major Bodies Of Water Join Together
- Where River Meets Ocean
Dredging is not that costly or difficult, but finding a place to put contaminated sediments is a problem. The Port of New York has been filling up abandoned Pennsylvania coal mines with its contaminated mud, but that is not a long-term solution.
While the problems of American estuaries are complicated and expensive, they pale in comparison to Asian estuaries. The entire nation of Bangladesh lies within the estuary and lower floodplain of the Ganges-Brahmaputra River.
Global sea-level rise is causing a loss of land, increased flooding, and increased salt intrusion in these estuaries.
The demand for water upstream for irrigation and domestic use significantly reduces freshwater flow through these systems. Unfortunately, its suffered industrial pollution in recent years, which is what gives it its brown color. The Rhine River, beginning its course in the Swiss Alps, flows throughout a good portion of Europe and has a history of being used for navigation and defense.
It starts in Germany and eventually empties out into the Black Sea. The Ilz River is a smaller mountain stream, running through the Bavarian forest before meeting with the 2 other rivers. It has a bluer color than the Danube and Inn Rivers, the later of which runs through Switzerland, Austria, and Germany.
It has a much bluer color than the Rhone, the two of which meet in Geneva. The Arve River also flows through France and Switzerland, but it receives its water from glaciers of the Chamoniz Valley, which gives it a high silt content and muddy-looking color. The meeting of two oceans in The Gulf of Alaska While technically not a confluence of two separate bodies of water, The Gulf of Alaska sometimes contains these stunning color variations.
The gulf contains different slow moving currents, or eddies, which harbor distinct sediments, one with a higher amount of heavier clay material that contains iron and changes the appearance of the water. Question of the Day: Have you ever seen a Confluence in real life? Let us know in the comments below!