Water diversion can permanently affect the character of wetlands.
Water diversion, the practice of changing the course of water bodies, is a common practice to create navigable waterways, drain wetlands for development or extract water from a body of water. The practice, however, is highly destructive to natural ecosystems. Even slight changes in an ecosystem can have significant cumulative effects on species diversity and distribution, but changing the dynamics of a vital resource like water can have lasting and irreversible effects on the environment.
Habitat Loss
Water diversion can contribute both to the loss of aquatic and wetland habitat and to interruptions in local water cycles. Every ecosystem is adapted to the availability and conditions of vital resources like water, so that each ecosystem has developed alongside specific conditions of water volume and cyclical wet and dry periods. Water diversion changes these variables and can lead to major reductions in the quantity of water available in an ecosystem. These losses reduce the amount of ground available for wetland organisms to live and the amount of water flow in aquatic systems and can even change water cycles like the frequency of flooding, all of which have major effects on habitat characteristics.
Habitat Fragmentation
Diverting water in a natural ecosystem can also have lasting effects on the spatial layout of an ecosystem. Depending on the scale of the diversion project, a new course of flowing water can both divide the aquatic ecosystems found in the original body of water and create physical barriers to land organisms. Large diversions can create obstacles for land mammals that need to travel between mating and feeding grounds, but even minimal diversions can affect insect distributions and seed dispersion systems for plants, potentially altering the entire food chain in the ecosystem.
Loss of Biodiversity
Changes in the availability of habitat and the distribution of species due to destruction and physical obstacles tend to have an overall negative impact on the amount of biodiversity in an ecosystem. As the habitat conditions in an environment change and a vital resource becomes more scarce, fewer species of animals can survive and reproduce in the area. The area may even be invaded by other species better adapted to dryer conditions or become dominated by the select organisms that can survive in the new conditions, both leading to an overall reduction in the diversity of organisms in the area.
Pollution and Human Impacts
Water diversion reduces the overall amount of water available in a given body of water. This change also affects the water body's capacity to absorb, dilute or process dangerous pollutants while preserving water quality. In many cases, the reduction of water without a reduction of the contaminant stream into the body of water pushes the ecosystem beyond its carrying capacity and leads to a severe deterioration of water quality for use by the ecosystem and human uses like drinking or sanitation.
