It has long been the quest of man to live by a river's edge and many have made their living along it's shores. It provides the many essentials that we need in the way of food, fresh water, and irrigation for our other food sources world wide. Modern technology has battled the river systems all over the world to make the rivers safer and more efficient in providing a stable, safe haven for people to build big cities and towns by. It is these methods that harm the natural surroundings more than they help.
Rivers have many bends and twists as they flow down toward the sea, and these obstacles are what slow the water down and cause flooding at times. Much of the time where the river narrows and becomes a bottle neck. This causes high water from trees that have eroded away and blocked the waters passage due to the bends in the river system. By straightening out these bends, the river flows quicker and without much resistance. The water does not have the ability to be slowed down and therefore decreases the chance for flooding along the river's route.
While this one problem of correcting flooding is going on by dredging the rivers' banks, the river is eroding away nutrient-rich materials that once flooded over onto farm land. Over a period of time, the soil along the rivers that have been straightened becomes degraded and turns barren from the lack of rich nutrients, and crops begin to fail because of bad soil. The river is unable to overflow its banks, and the fast moving river water cuts deeper into the river bottom eroding top soil from the banks as it flows.
Vegetation and soil are washed into the water and the fish and other wildlife habitats are changed forever by man's battle with the river. Loose soil clouds the river system, oxygen levels of the water decrease, and the fish die. Straightening out the river bends may decrease flooding, but it builds up a more frightening experience of fast moving water when heavy rains come to a region. With no resistance, the speed of water currents can wash out a bridge from ten miles upstream by undercutting the soft soil of the river bank. This causes many unforeseen problems later on by causing the river banks to collapse from the weight of vehicles and people who walk along these dangerous water edges.
Sometimes a river can cut so far back under the bank that a thirty foot section of bank will collapse back from the water's edge. The Mississippi river had this major problem and the Army Core of Engineers began to place concrete matting along the entire banks of the river system, but now other problems persist with the accumulation of sand bars when the river is low in shipping channels. The constant dredging to keep the river open to shipping is forever sealing the fate of New Orleans as it drops inches below the ocean water table each year.