Here is an image that i found last week in a document that I was reading. It details the Colorado River delta at the town of Matagorda from between 1855 to present, showing that in 1855 the Colorado emptied straight into an open bay (not the East West seperated bays we have now...) pretty cool history.
thought i'd share.
The small rectangular grid at the top of each inset is actually the town of Matagorda.
I can remember stories from my grandpa that when there was only a muddy one lane road to go to the beach. You would have to have a car load of guys and if you met another car the guys would lift the car to the side of the road and let one car by and then move the car back onto the road.
So, the landmass that splits the bays is due to silting or was their earth brought in to form the landmass? Seems like 160 years is not enough time for natural silting to form all of that land surface area...
Agriculture sped up the process of the river delta by turning praries into fields thus increasing the amount of erosion, therefore the river started to carry more and more sediment causing the river delta to prograde. It would be cool to do some research on what the population was and dam construction along the river at this time.