Warmup 10/22/12 As the population of Durham increases… What happens to the water demand? How does that affect the water supply? What do we need to do with the waste water?

Pollution! 2.4.1d Explain how pollutants might flow through a watershed and affect inhabitants that share the same watershed. 2.4.2a Evaluate issues of ground and surface water pollution, wetland and estuary degradation, and salt water intrusion.

Groundwater Fifty percent of the United States population depends on groundwater for daily drinking water. Groundwater is also one of our most important sources of irrigation water. Unfortunately, groundwater is susceptible to pollutants. Groundwater is generally a safe source of drinking water, however, there are concerns that contamination may increase as toxins dumped on the ground in the past make their way into groundwater supplies.

Ground Water

Groundwater Pollution Pollutants that contaminate groundwater may be some of the same pollutants that contaminate surface water. Compounds from the surface can move through the soil and end up in the groundwater. For example, pesticides and fertilizers can find their way into groundwater supplies over time.

Pollutants to Ground Water

Ground Water Pollution Once the pollution is in the ground, there is not an easy way to remove it. Usually the deeper the pollution is in the ground, the longer it takes to remove. Why do you think this is?

Sources of Ground Water Pollution

Surface Water Surface water pollution occurs when hazardous substances come into contact and either dissolve in or physically mix with the water. The most effective approach for cleaning up contaminated surface water is to prevent further discharges from contaminated sources and enable natural biological, chemical, and physical processes to break down the existing contamination.

Contaminated surface water It can also impact the health of wetlands and impair its ability to support healthy ecosystems, control flooding, and filter pollutants from storm water runoff. Contaminated surface water can also affect the health of animals and humans when they drink or bathe in contaminated water or, for aquatic organisms, when they ingest contaminated sediments.

Spills

How does surface water pollution affect the Ecosystem? A change in the water chemistry due to surface water contamination can negatively affect all levels of an ecosystem. It can impact the health of lower food chain organisms and, consequently, the availability of the food supply up through the food chain.

Wetland Pollution

Concentration of Contaminants One of the major concerns associated with contaminated surface water is the ability of aquatic organisms, like fish, to accumulate and concentrate contaminants in their bodies. When other animals or humans ingest these organisms, they receive a much higher dose of contamination than they would have if they had been directly exposed to the original source of the contamination.

Wetland and Estuary Degradation

Wetlands Wetlands and riparian areas typically occur as natural buffers between uplands and adjacent water bodies. They act as natural filters of nonpoint source pollutants, including sediment, nutrients, pathogens, and metals, to water bodies, such as rivers, streams, lakes, and coastal waters. It is important to preserve and restore damage to wetlands and riparian areas because these areas can play a significant role in managing adverse water quality impacts. Wetlands and riparian areas help decrease the need for costly stormwater and flood protection facilities.

Estuary An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and ocean environments and are subject to both marine influences, such as tides, waves, and the influx of saline water; and river influences, such as flows of fresh water and sediment

Salt Water Encroachment

Salt Water Intrusion Saltwater intrusion is the movement of saline water into freshwater aquifers, which can lead to contamination of drinking water sources and other consequences. Saltwater intrusion occurs naturally to some degree in most coastal aquifers