APES Study Guide

Water Table

The upper level of an underground surface in which the soil or rocks are permanently saturated with water.

Percentage of Liquid Freshwater Available to Organisms

Approximately 0.3% of the world's liquid freshwater is available for human use and sustenance.

Hydrologic Cycle

The continuous movement of water on, above, and below the surface of the Earth.

Leading Cause of Illness Globally

The world's single largest cause of illness is unsafe water.

Hydrological Poverty

A condition where communities lack access to adequate water resources.

Coverage of Earth's Surface by Water

About 71% of the Earth's surface is covered by water.

Goals of Creating Dams and Reservoirs

To store water, generate hydroelectric power, and control flooding.

Pros and Cons of Dams

Pros include water supply and flood control; cons include ecological disruption and displacement of communities.

Aquifer

An underground layer of water-bearing rock that can yield water to wells and springs.

Majority Use of Water

Globally, the majority of water is used for agricultural irrigation.

Subsidence

The gradual sinking of the Earth's surface due to the extraction of groundwater.

Ownership of Water Resources

Most water resources are owned by governmental or corporate entities.

Consequences of Removing Groundwater

Can lead to land subsidence, reduced water quality, and ecosystem disruption.

Ogallala Aquifer Water Level Decrease

The Ogallala aquifer water level has been lowered by about 30 meters.

Effective Way to Reduce Flooding

Creating wetland areas to absorb excess water is one effective method.

Problems with Colorado River Water Usage

Overuse has led to reduced water flow and ecological damage.

Desalination Method

Reverse osmosis is the method that uses high pressure to force saltwater through a filter.

Human Activities Contributing to Flooding

Urban development, deforestation, and poor land management practices.

Main Cause of Water Waste

Inefficient irrigation practices are the main cause of water waste.

Lake Washington Pollution Source

Sewage treatment plants added nutrients that caused degradation in Lake Washington.

Safe Drinking Water Standards (Coliform Bacteria)

Less than 1 colony of coliform bacteria per 100 ml of water is considered safe for drinking.

Safe Swimming Water Standards (Coliform Bacteria)

Less than 200 colonies of coliform bacteria per 100 ml of water is considered safe for swimming.

Indicator of Water Quality

The number of dissolved oxygen levels in water is a good indicator of water quality.

Leading Cause of Water Pollution

By far, the leading cause of water pollution is agricultural runoff.

Global Access to Clean Drinking Water

The World Health Organization estimates that 1 in 10 people do not have access to clean drinking water.

Organisms Least Likely to Cause Water-borne Disease

Viruses are the group of organisms least likely to cause water-borne disease.

Oxygen Depletion in Water

A body of water can be depleted of its oxygen by excessive organic waste leading to decomposition.

Common Nonpoint Sources of Pollution

Agricultural runoff and urban runoff are common nonpoint sources of water pollution.

Common Point Sources of Pollution

Industrial discharge and wastewater treatment plant effluents are common point sources.

Dissolved Oxygen Levels and Temperature

Dissolved oxygen levels in waterways generally decrease as their temperature increases.

Eutrophication of Water Bodies

Eutrophication is the enrichment of water by nutrients, often leading to excessive algae growth.

Great Lakes Freshwater Percentage

The Great Lakes possess about 20% of all surface freshwater on Earth.

Aquatic Ecosystems for Pollutant Dilution

Estuaries and wetlands are most capable of diluting, dispersing, and degrading pollutants.

EPA Water Safety Violations

According to the EPA, one in 10 Americans drinks water from a plant that has violated safety standards.