• Dams are useful in many ways, but their monitoring and removal has been a recent environmental management project on many river systems.hoover dam image by Dave from Fotolia.com
  
  Sound management of the environment has been an increasing focus of many governments since the late 1960s. Although environmental management goes back into prehistory when people first started managing resources and purposely manipulating their surroundings, modern inceptions of environmental management often revolve around remediating damaged ecosystems and cleaning up toxic spills.
  
  

Mangrove Forest and Wetland Restoration

• Coastal populations are often seasonally affected by severe storms and subsequent flooding. Natural barriers to flooding and storm surges like mangrove forests and wetlands have been removed in favor of converting the land into housing tracts and agriculture, but now many ecologists and disaster planners recognize their importance as a defense mechanism against the battery of high winds, waves, and rain. Replanting mangroves in Florida, for example, has built up strong roots to keep sediment in place, and they also act as a barrier against storm winds. Further restorations to the Everglade wetlands to their natural state has provided a massive sponge to help absorb water after coastal floods, and these same wetlands can also filter out contaminants that have been spread by flood waters.
  
  

Dam Removal

• Although rivers offer a great resource for generating hydroelectric power and diverting water to farm irrigation, riverine ecosystems are severely disrupted by damming. Fish populations cannot pass the physical barrier of dams, and installed fish ladders are met with extremely limited success. River sediment gets stuck behind dams, accelerating erosion of deltas and riverbanks downstream which are normally fed by this sediment.
  
  Removing a dam is a massive engineering challenge, and requires in-depth planning with local residents to avoid problems like cutting off a water or power source, or causing intermediary flooding from initial post-removal surges of water. It is unlikely that massive hydroelectric generators like the Hoover dam will be removed in the foreseeable future, but the removal of smaller dams in other river systems has already shown positive recovery to pre-dam function and ecosystem health, with fish populations and normal sediment flow returning to normal.
  
  

Spill Cleanup

• Accidental release of environmental contaminants can be detrimental to human and environmental health, and spill clean up projects are of high priority in the United States. The worst cleanup projects are rated "Superfund" sites by the Environmental Protection Agency. These are extremely contaminated areas which are continually monitored and long-term spill cleanup efforts are enforced. Superfund cleanups receive funding through CERCLA, an acronym for the Comprehensive Environmental Response, Compensation and Liability Act of 1980. The law was passed in response to environmental disasters like the Love Canal and Times Beach toxic spills, and has been successful in funding long-term cleanup efforts of some of the United States' worst spill sites. Some spill clean up methods even incorporate biological remediation, like certain species of mushrooms which can break down and absorb motor oil from soil.