I don't mean to be a wet-blanket with my comment, just to point out the potential negative impacts of human engineering, when such engineering is not well-thought-out.
We (in gulf south US) have had similar engineering projects with the Mississippi River (et al) over the course of the last couple of centuries. Largely the goal has been to keep the rivers from flooding their banks, which they are keen to do in various places, mostly yearly. The impetus for this is of course to aid in the development of major cities and keep farmlands productive.
What is happening as a result, however, is now known to be truly disastrous for my home state of Louisiana, where the adage is "Louisiana is losing a football field an hour"[0] due (in large part) to the levees preventing the sediment from the rivers from depositing along the coast and helping to keep the coastal marshes in place. There are other (secondary) ill effects as well, that are perhaps more subtle. I was on a native plant society field trip last week to study one of our more southerly "bottomlands" (mixed swamp/marsh/upland habitat). What we found is that many of the freshwater-wetland-specific trees are becoming severely unhealthy and/or dying due to the influx of brackish water (mixed salt/fresh) from the gulf/lakes in the area. This is largely due to the loss of sediment that normally would be deposited from the Mississippi river - that sediment helps to reform the uplands surrounding the bottomlands, and without it, other water sources are able to carve a path in. Some of this, of course, is natural, and part of how Louisiana's wetlands normally change over time, but they do seem to be changing more rapidly.
Fortunately, there is a large amount of interest among Louisianians to fix these problems. There are some more large engineering projects designed to undo some of this damage, specifically with projects to reroute the sediment to where its needed (aka diversions)[1]. So I'm hopeful we'll be able to stop and maybe reverse the damage being done
We (in gulf south US) have had similar engineering projects with the Mississippi River (et al) over the course of the last couple of centuries. Largely the goal has been to keep the rivers from flooding their banks, which they are keen to do in various places, mostly yearly. The impetus for this is of course to aid in the development of major cities and keep farmlands productive.
What is happening as a result, however, is now known to be truly disastrous for my home state of Louisiana, where the adage is "Louisiana is losing a football field an hour"[0] due (in large part) to the levees preventing the sediment from the rivers from depositing along the coast and helping to keep the coastal marshes in place. There are other (secondary) ill effects as well, that are perhaps more subtle. I was on a native plant society field trip last week to study one of our more southerly "bottomlands" (mixed swamp/marsh/upland habitat). What we found is that many of the freshwater-wetland-specific trees are becoming severely unhealthy and/or dying due to the influx of brackish water (mixed salt/fresh) from the gulf/lakes in the area. This is largely due to the loss of sediment that normally would be deposited from the Mississippi river - that sediment helps to reform the uplands surrounding the bottomlands, and without it, other water sources are able to carve a path in. Some of this, of course, is natural, and part of how Louisiana's wetlands normally change over time, but they do seem to be changing more rapidly.
Fortunately, there is a large amount of interest among Louisianians to fix these problems. There are some more large engineering projects designed to undo some of this damage, specifically with projects to reroute the sediment to where its needed (aka diversions)[1]. So I'm hopeful we'll be able to stop and maybe reverse the damage being done
[0] https://www.nola.com/news/environment/article_3128024a-cc03-... [1] https://coastal.la.gov/midbarataria/