what are the benefits and the negatives of dams and resevoirs?
how do they affect ecosystems if at all?
http://geography.about.com/od/waterandice/a/damsreservoirs.htm
http://chamisa.freeshell.org/dam.htm
thanks so much.
You're welcome.
Dams and reservoirs have both benefits and negative effects. Let's delve into each aspect and discuss their impact on ecosystems as well.
Benefits of Dams and Reservoirs:
1. Water Supply: Dams and reservoirs store water, ensuring a steady supply for drinking, agriculture, and industrial purposes, particularly in regions with variable rainfall patterns or water scarcity.
2. Hydropower Generation: Dams harness the potential energy of flowing water to produce electricity, constituting a renewable and clean source of energy.
3. Flood Control: Dams can regulate water flow, mitigating the risk of flooding by storing excess water during heavy rainfall and releasing it gradually.
4. Recreation and Tourism: Reservoirs often provide opportunities for recreational activities like boating, fishing, and swimming, attracting tourists and supporting local economies.
Negative Effects of Dams and Reservoirs:
1. Displacement of Communities: The impoundment of water behind dams can displace human populations, requiring the relocation of communities and affecting their livelihoods.
2. Ecological Disruption: The alteration of river flows and the creation of reservoirs can disrupt the natural flow regimes of rivers, impacting the habitat and migration patterns of aquatic species.
3. Sediment Accumulation: Dams trap sediment that would naturally flow downstream, leading to sediment accumulation in reservoirs. This can affect downstream habitats, reduce reservoir storage capacity, and impact the fertility of agricultural lands.
4. Altered Water Quality: Changes in water temperature, oxygen levels, and nutrient concentrations in reservoirs can impact water quality and affect aquatic ecosystems, potentially leading to the growth of harmful algae blooms.
Impact on Ecosystems:
Dams and reservoirs can profoundly affect ecosystems, although the specific impacts vary depending on factors such as the size of the dam, location, and design. Some common ecological effects include:
1. Habitat Fragmentation: Dams form physical barriers, fragmenting river systems and separating habitats. This disrupts the natural movement and migration of aquatic species, impacting their ability to find suitable breeding grounds or access food sources.
2. Changed Flow Regimes: The altered flow patterns caused by dams can affect the vegetation and invertebrate communities that rely on specific water flows for their life cycles. This can disrupt the food chain and affect the overall ecosystem balance.
3. Loss of Riparian Zones: The creation of reservoirs often leads to the flooding of riparian zones, which are vital habitats for many species, including birds, amphibians, and mammals. This loss of habitat can have cascading effects on the entire ecosystem.
4. Altered Nutrient Flows: Dams can interfere with the natural transport of nutrients downstream, affecting the fertility of riparian areas and other downstream ecosystems.
In summary, while dams and reservoirs provide numerous benefits, they also have negative consequences for both human communities and ecosystems. It is crucial to carefully consider these factors and incorporate mitigation measures when planning and managing these infrastructure projects to minimize their ecological impacts.