Environmental science chapter 14 discussion

What are the three main categories of water use? Give an example of each.

1.) Agricultural Uses: No matter a nation's income, most fresh water is used for agriculture. Farmers and ranchers who produce the food you eat must use water for their crops and livestock. 2.) Industrial Uses: Most manufacturing and industrial processes that create everything from the bed you sleep on to the gasoline that powers the bus you ride to school require water. 3.) Personal Uses: Every day, an average person in the United States drinks between 2 and 5 liters of water, but we also use water for bathing, cooking, doing laundry, and flushing the toilet.

6 pollutants & their diseases

1.) Vibrio Cholerae: Cholera 2.) Entamoeba histalytica: dysentery 3.) E. Coli: E. Coli infection (dysentery) 4.) Giardiasis (protozoan): Giardiasis 5.) Schistosomia: Schistosomiasis

Explain the significance of a watershed.

A watershed includes all of the land area that supplies water to a particular river system. Watersheds are sometimes called drainage basins because they drain into a river system the same way that rainwater drains into street or house gutters.

What is a watershed? Why is it more effective to manage an entire watershed as compared to a single water source?

A watershed includes all of the land area that supplies water to a particular river system. Watersheds are sometimes called drainage basins because they drain into a river system the same way that rainwater drains into street or house gutters. The interconnected nature of watersheds greatly influences how they are managed. It is easier to maintain water pollution at each source rather than at the point where the water enters the ocean because the pollution multiplies as the water flows downstream.

Describe strategies for addressing water depletion.

Addressing freshwater depletion will largely depend on strategies that decrease water demand. When an area runs out of fresh water, we can do one of two things: increase our supply or decrease our demand. Solutions that increase supply can have immediate effects. Lowering demand is more difficult to do, but will likely be necessary in the long term.

How does agriculture contribute to groundwater depletion?

Agricultural Solutions: Farmers can conserve water by adopting efficient irrigation methods and selecting climate-appropriate crops. Drip irrigation systems target individual plants and introduce water directly into the soil. Drip irrigation reduces water lost to evaporation and runoff. Experts estimate that using drip irrigation instead of traditional methods can cut agricultural water use in half. The biggest cause of groundwater depletion is irrigation.

Discuss how fresh water can be both renewable and limited

As a natural resource, fresh water is renewable. However, quantities of fresh water on Earth are limited. Water is considered a renewable resource because the water cycle, or hydrologic cycle, constantly recycles it. You can't drink salt water or effectively water crops with ice. Most of people's day-to-day activities rely on fresh, liquid water.

What is the difference between point and nonpoint sources of water pollution? Give an example of each.

Every type of water pollution comes from either a point or a nonpoint source, as shown in the figure. Point-source pollution comes from distinct locations, such as a factory or sewer pipe. In contrast, nonpoint-source pollution comes from many places spread over a large area. As runoff produced by rain and snowmelt makes its way across farms, lawns, and streets, it picks up accumulated fertilizers, pesticides, salt, oil, and other pollutants.

Explain how most groundwater is accessed.

Groundwater is held in aquifers and accessed by wells. Any precipitation reaching Earth's land surface that does not evaporate, flow into rivers, or get taken up by organisms soaks into the surface. Some of this water trickles downward through the soil to become groundwater, water found below Earth's surface. Groundwater makes up about one fifth of Earth's freshwater supply and plays a key role in meeting human water needs.

Why might you have to dig a well deeper if it is overused?

If the amount of water in a well becomes overused then the exposed soil can erode and the water supply can be depleted. If you have used up the water that the well originally reached then you have to dig the well even further down into the supply of groundwater to have a new and untouched supply of groundwater.

Why is groundwater pollution so hard to clean up?

It can take decades to clean up groundwater pollution, so every effort should be made to prevent it from occurring. Groundwater sources have become contaminated by pollution from industrial and agricultural practices. Groundwater pollution is largely hidden from view and is extremely difficult to monitor. Often, groundwater contamination is not discovered until drinking water is affected.

Explain how using nitrogen-rich fertilizers can affect algal blooms in the oceans.

Nutrient pollution is a problem in the ocean, it is nitrogen that does the most damage. One type of algal bloom is nicknamed red tide because the algae produce reddish pigments, as shown in the figure. Some red tides and other harmful algal blooms release powerful toxins that make their way through the food chain, causing illness and death among zooplankton, fish, marine mammals, birds, and humans. Harmful algal blooms also hurt the economy. When one occurs, beaches are closed and fishing must stop.

Explain how water diversions and dams affect surface water depletion.

Sometimes it is not possible to rely on a naturally flowing river or stream for water. The flow may be too fast or too slow. Or, the amount of water available may vary too much in different seasons. To help regulate river flow and to build a stable supply of water, a dam may be built. A dam is any obstruction placed in a river or stream to block its flow. Dams create artificial reservoirs, large lakes that store water for human use.

Describe the steps involved in a typical public drinking water treatment process.

The EPA sets standards for more than 80 drinking water contaminants, which local governments and private water suppliers must meet. Unless your water comes from a well on your property, it is usually treated with chemicals and run through filters before being sent to your tap. Pathogens are killed, sediment is filtered out, and chemical pollutants are removed, making the water safe to drink.

Provide details from the text that support the conclusion that liquid fresh water on Earth is a limited resource.

You can't drink salt water or effectively water crops with ice. Most of people's day-to-day activities rely on fresh, liquid water. The remaining 21%, found in lakes, rivers, the atmosphere, organisms, and soil, is liquid. Only some of this 21% is drinkable or usable for crops. Clearly, useful fresh water is a very limited resource.