I tried to find where the mississippi river spits out into the ocean, but I can't actually figure out what I'm looking at here. what is this? is it man-made? street-view doesn't help, it just looks like land, but from above it all looks like this water-land shit.explain it
>>18580359it's called a river dela
>>18580359The stitching of satellite imagery is quite bad here, it's easier to see on other sources. Yes it's a river delta, the river splits into smaller channels, some of which will have embankments and lock gates for the purposes of navigation (boats). That's the man-made part but that's more stabilisation of the existing situation, man didn't decide to split the river up, that happens naturally.The Mississippi is a very large river with a huge catchment area, it transports A LOT of sediment. Particularly due to bad farming practices which cause major top soil erosion, all the dust and soil ends up in the river and gets carried through fast-flowing sections and deposited at low-speed sections. Which, as a result, get shallower and shallower and that's what causes the river to split. Rivers also usually flow slower at the mouth due to waves coming in from the sea in the opposite direction. That's what causes all these wetlands. Without intervention it will grow more and more in a fractal pattern.
>>18580391interesting. thanks
>>18580391mark twain talked a bit about the sediment stuff. exactly how much is due to bad farming practices, and when did that start? how much has this effected what the delta looks like over the centuries?
>>18581075Large rivers naturally carry massive amounts of sediment and it isn't primarily caused by bad agricultural practices. The best example is probably River Meander in Turkey. The post city of Miletos was established in the Bronze Age on a promontory dozens of kilometers away from the river mouth, but the bay silted up over millenia and the ruins of the city now sit on an inland hill 6 km from the coastline.The particle size of sediment deposited on a river bottom depends on the flow speed of the river. Upstream speeds near hills and mountains are higher due to a large gradient and are able to move small rocks and gravel along the river bottom. As the terrain gets more level and the gradient gets shallower (especially on floodplains near a coast), finer and finer particle sizes from sand to silt are finally able to settle down on the bottom in the less energetic river, although clay-sized particles are usually carried all the way to the ocean. The finest clays can only be deposited in lacustrine environments with no flow like glacial lakes, otherwise they stay suspended in the water column.River flow speed also depends on small-scale river bends (e.g. "meandering" rivers, named after the one in the pic). Flow is less energetic on the inside bank of a bend, and more stuff is deposited here, while the outer bank is eroded. Deltas are made of shifting bars of sediment, although you may need to measure the changes of channels over human lifetimes to notice large natural deviations.What might blow your mind is that rivers often don't stop existing just because they reach the coast, but they may carve giant underwater canyons on the sea floor of a continental shelf as they continue flowing beneath the surface. The underwater Hudson Canyon is a famous example of such.The Mississippi is quite ancient and you should be looking at timescales of tens of millions of years instead of human history.
