Dramatic Confluences

Confluences occur wherever two streams come together. If the gradient is low (i.e., nearly level) and the properties of the two streams are very different, the confluences may be characterized by a dramatic visible distinction as the mixing occurs only slowly. This map -- based on an EarthPorm article -- shows some of the most dramatic examples from around the world -- just ten that stand out, among the millions of confluences on the planet.

Explore the map to see where these confluences occur, and descriptions of the rivers involved -- each situation is unique. Notice that the satellite imagery in some cases is not as dramatic as the photographs that are shown, for two basic reasons. Either the satellite imagery represents a part of the electromagnetic spectrum in which the distinctions are not as visible, or the timing of the satellite imagery does not match seasonal effects that are involved in some of these cases.

O'Maley Middle School, Gloucester -- December 5

Image: WikiMedia

42° 37' 44" N
70° 40' 23" W
Learn more about Lat/Long 

Today the EarthView team is visiting the northeasternmost portion of the Bay State: the Ralph B. O'Maley Middle School is just a couple of miles from the Atlantic Ocean in the famous fishing town of Gloucester.

Located on Cape Ann, this community is connected in many important ways to the Gulf of Maine, a "sea within a sea" that receives the waters of 60 watersheds. Geography students at O'Maley have recently been studying the nearby Gulf, which has some of the richest fisheries and most interesting tides in the world.

The sense of place is celebrated by new local restaurant, Latitude 43, which has a nautical theme and a geographic name. The team knows about the place because a son of team member Dr. Domingo was the construction manager.

When we returned from Gloucester, a student shared The Wreck of the Hesperus, Longfellow's famous poem based on two shipwrecks -- one near Gloucester and the other near Boston. It is required reading for many students in nautical New England towns.

During our visit, we spoke with some of the classes about the geography of currency. Every country in the world decides what currency it will use, and most of them print their own. When traveling, it is important to know the value of the currency. A sandwich that costs 5 dollars in the United States would cost 13 reais (HAY-ice) in Brazil and 132 cordobas in Nicaragua. These relationships -- known as exchange rates -- are always changing, and can be calculated on web sites such as XE.com.

We were speaking on the anniversary of the death of Nobel Laureate Nelson Mandela. His life was an inspiration, of course, to many people throughout the world, but was especially meaningful to the EarthView team, because our own Dr. Domingo began life as a black South African, and left for the United States before the dream of ending apartheid could be realized. Now when he visits his family, it is a very different country from the one in which he grew up.

Of course, we also talked about Nobel Laureate Malala Yousafzai, who will formally receive her award next year. In March, we learned that one of our favorite university geography texts was dedicated to her work on behalf of young women everywhere who want to learn.

Image: Rondonia Web

Several classes heard from Dr. Hayes-Bohanan about Rondônia, the state of Brazil where he studied to earn his doctorate in Geography & Latin American Area Studies. The photograph above is of a carving purchased during that field work, from an artist known as Anká. If you did not hear the story -- which involves a leaky boat, a 100-foot climb in the rain forest and many details he forgot to mention -- you can read it about it in Folha da Frontera (#3), a newsletter that was sent from the field. It is on Rondônia Web, along with a lot of other information about this part of the Amazon basin, and especially about its growing cities.

Lagniappe: Cape Ann or Annisquam Island?

During our visit, one of the geography teachers at O'Maley told the EarthView team that Cape Ann is actually an island. We had crossed a bridge to get to it, after all, and in fact there is no way to drive or walk there without crossing one of three bridges over the Annisquam River, and a quick look at Google Maps confirms this.



Because rivers to not separate islands from continents, we decided to investigate. Throughout most of its course, the Annisquam appears to be a natural river, mostly estuary. In the headwaters at the far southeastern end of the river, however, the banks are unnaturally straight, suggesting human engineering, and the name Blynman Canal confirms this. The history of this very short canal is an interesting one, having first opened in 1643, but not being permanently navigable until two centuries later.

By coincidence, we had mentioned the anniversary of the South Hadley Canal to some of the students. It is credited with being the first canal in the United States used for navigation, but as we can see, such superlative titles are always subject to debate.

Modern Antique

Image: National Geographic Education

As we posted back in September, one of the great benefits of EarthView is that it allows us to see a map of the world at a relatively large scale and with minimal distortion. (The only distortion results from the flattening of Antarctica so that we can walk inside the globe.)

As National Geographic explains, all flat maps involve distortion, just as flattening an orange peel will require some combination of stretching and tearing. But on this date -- December 2 -- it is important to think about the projection that has probably caused more confusion about the world than any other. For it was on December 2, 1594 that German cartographer Gerardus Mercator died.

The image above represents the most modern remote-sensing technologies, with the Digital Numbers captured by many satellites in countless data files expertly converted to meaningful colors and stitched together into a single map. It also represents a projection technique best suited to the age of sail -- Mercator makes the poles infinite in order to represent direction clearly. In its recognition of Mercator's death, National Geographic Education explains the problems that widespread adoption of this map has caused.

America's First Canal

Thanks to the MassMoments project of the Massachusetts Foundation for the Humanities, we learn that today marks an interesting anniversary in the geography of New England. It was on December 1, 1826 that the first steamship passed through the South Hadley Canal. The canal is still visible in the satellite imagery below, which makes clear its purpose: it provided a means of navigating around the rocky South Hadley Falls area of the Connecticut River.



As the MassMoments post explains, this canal was the first in the United States to carry river traffic, as it did for nearly forty years. This is a key bit of the "geography behind history" for the entire Connecticut River Valley, which remains the key north-south corridor in New England.

The canal last operated in 1863, and played a part in its own demise. By increasing the importance of the river as a transportation corridor, the canal helped to make way for the railroads that would eventually replace it. Those, in turn, led eventually to the establishment of highways such as Interstate 91, which are the most common ways of following the course of the river today.

This map shows the Connecticut River, its watershed, major tributaries, and major highways. It is one of many map and geography resources available from the Connecticut River Watershed Council. Please explore the collection. As the Council points out, no single map can capture the complexity of this watershed -- over 11,000 square miles draining to a 406-mile main channel..