Dams and Channelization

• The creation of dams and channels intended to benefit applications in agriculture, like irrigation and livestock watering; navigation, such as maneuvering watercraft from larger to smaller waterways and power production, from water movement across a generator, accounts for a large portion of recognized negative human impact on freshwater ecosystems. An example of the impact of damming can be seen on Thailand's Mun River. The dam was built in the early 1990s and within a few years, the overwhelming majority of the river's aquatic species had disappeared. Interrupting the natural flow of water through an ecosystem affects many aspects of a region, including drying up natural aquifers that are essential drinking water sources.
  
  

Waste Disposal and Drilling

• The U.S. Environmental Protection Agency reports that up to 0.4 percent of fresh water aquifers are substantially contaminated by dumps and landfills. Fresh water becomes contaminated mostly when water sources, like rain and runoff, percolate down through waste disposal sites. The waste water then contaminates ground water supplies and then often proceeds to contaminate crops by way of natural and manmade soil irrigation.
  
  

Overconsumption

• The growing demand for water upon an increasingly overcrowded planet is having a negative impact on freshwater ecosystems as well. This overuse occurs in agriculture, urban and industrial applications. Studies show that we cannot sustain the current rate of decline seen in freshwater ecosystems. Lifestyle practices that depend on mass overconsumption may prove to be a large factor in worsening climate change and lead to an unnatural redistribution of resources.
  
  

Loss of biodiversity

• The loss of freshwater ecosystems, instigated by human contact and use, reaches across species. The majority of the planet's food chains are dependent on freshwater sources, perhaps on a significantly larger scale than other natural resources. Many animal and plant species have been shown to adapt to changing and fluctuating soil nutrients and composition, for example. Many plants adapt to water shortages, as well, as is seen in desert habitats, but all terrestrial flora and fauna need a basic, consistent fresh water source to survive.