Down Go the dams s ome 800,000 dams exist around the world, but small ones—and even some large ones—are increasingly being removed so rivers and streams can recover. ■ Ecologists are learning, however, that removing or lowering dams takes a great deal of careful planning and active intervention because sometimes the dams confer environmental benefits, such as holding back toxic sediments or blocking the progress of invasive species. ■ Before decommissioning a dam on Fossil Creek in Arizona, managers poisoned exotic fish and airlifted native species to safety. Such strategies could prove key to the success of future dam removal projects.
-often an issue facing managers is what to do with accumulations of dirt and debris. - The release of sedi ments trapped behind a dam’s walls can choke waterways, muddying the envi- ronment and wiping out insects and al- gae, which are important food for fish. - When engi- neers removed the Fort Edward Dam on the Hudson River in 1973, concentra- tions of PCBs rose in downstream fish and remained high for many years Summary: -There is 800,000 dams in the world. dams are good in the way that they hold our water but are bad because it can disrupt nutrients to be spread in the river.The process is not very easy, some dams can actually help in the way by holding off toxic chemicals and invasive species. but having them DESTROYED is a long progress and very COSTLY. one reason to not destruct the dams is that the SEDIMENTS can choke waterways. they can wipe out algae, fish, and other organisms.
my opinion -in my opinion i BELIEVE that dams are good and bad. They are good in the way that they provide the security to hold water for us. the bad side is when they are destroyed. They can hold back the nutrients that the river needs. When they are destroyed the toxic chemical can be spread as well a type of invasive species. a problem can be that one side of the dam can be INTOXICATED and when the dam is destroyed this can SPREAD into the other side.
says who:well this has been researched so i BELIEVE that scientist have said the good and bad benefit of dams. so what:This is important to know because dams can be the future or be the past depending on how much research we can get from water and everything else in the water. What if: If we DON'T pay attention to the factors that everything can go wrong. More rivers can be destroyed and gone such as those who have just as those who have dried up. What does it remind me of: this reminds me of society as it self because we are like a wall holding back nature to grow and grow as an ENVIRONMENT.