Watersheds and Wetlands

CHAPTER 1

Lesson 1.5

Factors That Affect Wetlands and Watersheds Human Activities Watershed Quality Health of U.S. Watersheds Pennsylvania’s Stream ReLeaf Program Pennsylvania’s Watershed Education Program Natural Events Affect Watersheds and Wetlands

Academic Standards for Environment & Ecology

Standard 4.1.10.E Identify and describe natural and human

events on watersheds and wetlands.• Describe how natural events affect a watershed

(e.g., drought, floods).• Identify the effects of humans and human events

on watersheds.

Factors That Affect Wetlands and Watersheds

• Wetlands and watersheds are controlled by complex interactions.

• Several types of interactions occur including chemical, physical, and biological interactions.

• These interactions are controlled or influenced by one of two types of processes or events

Human activities Natural processes

Human Activities• Human activity has drained, dredged, filled, and

destroyed the functionality of many wetlands.

• Human activities which have influenced wetlands and watersheds include:

• Changes in agriculture, urbanization, construction, mining, industrial processes, waste disposal, and mosquito control.

• Pollution from sedimentation, excessive nutrients loads, heavy metals, and pesticides pollution.

Human Impacts on the Water Cycle

Three most common problems associated with water:

1.Changing the Earth’s Surface• Natural ecosystems should have very little runoff• Precipitation should be met by vegetation and infiltrate,

recharging the groundwater• As forests are cleared, and human development increases, the amount of runoff also increases, because of this: Flooding is more likely

Sedimentation occurs bringing many pollutants into waterways

Recharge of groundwater is drastically reduced

2. Pollution

• Wherever wastes are put, they inevitably reach the water cycle

• Smoke or fumes released into the air dissolve in water vapor and returns to the earth as polluted precipitation (Acid Rain)

• Fertilizers, pesticides, road salt, gas, oil, and other chemicals can leech into the groundwater or runoff into streams

• Water used in washing and flushing away wastes directly adds to polluted surface waters unless there are proper treatment systems available

3.Withdrawals from use

Two areas of usage:1. Non-Consumptive: Water is in control of humans to be used over

Examples: Water used in homes and industry for washing and flushing material away Can be used over if … 1. Quality of the water is adequate 2. It is treated to remove pollutants

2. Consumptive: Water is out of the control of humans and cannot be reused

Example: Irrigation Once water is used on agriculture, humans have

no way of reusing it again

• How has Pennsylvania agriculture impacted the overall quality of wetlands and watersheds?

Agricultural practices can disrupt or destroy wetlands in a variety of ways.

• Degradation, as a byproduct of harvesting forest or food products,

• Irrigation ditches installation and maintenance,• Inefficient handling of animal waste, • Overgrazing of livestock in wetland area, and • Runoff containing pesticide and herbicides used on

crops.

• Pesticides and herbicides can enter wetlands primarily two ways Contaminants settle out of the air Contaminants enter wetlands through runoff, and

settle out as the velocity of the water decreases.• At high enough concentrations, these compounds can

pose problems to livestock, wildlife, and humans.

Natural processes

• Rainfall

• Evaporation

• Water wastage

• Clearing of forests

• Climate changes resulting from global warming and El Niño.

Natural Events Affect Watersheds and Wetlands

• Nature plays a role in changing Earth’s watersheds, which directly effects the organisms within the watershed.

• These natural events include floods, erosion and deposition of materials, volcanic eruptions, fires, wind, and global climate change.

Watershed Quality

• Overall watershed quality, which includes wetlands, is assessed by a variety of different local, state, and federal agencies.

• These agencies use the Index of Watershed Indicators (IWI) to assess aquatic resources.

• Two types of IWI indicators include Condition indicators Vulnerability indicators

Condition Indicators

• These indicators reflect actual conditions in a watershed. Example: fish and shellfish

advisories are issues when high levels of pollutants are recorded, to prevent humans from consuming large amounts of potentially harmful chemicals.

Vulnerability Indicators

• These indicators measure the vulnerability of a watershed, showing if human activities have produced negative effects on a watershed. Example: human population growth is used as an

indicator because an increased amount of people in a given area can stress watersheds and produced potentially harmful effects on watersheds.

Drought• Definition: period during which the amount of

precipitation that falls in an area is lower than normal.

Drought Emergency• Definition: period during which agencies, suppliers,

and users, including the general public, are asked or required to take measures to reduce water consumption by at least 15 percent

Drought Watch

• Definition: period during which governmental agencies, public water suppliers, water users, and the public are alerted to the possibility of drought.

Drought Warning

• Definition: period during which measures are taken to avoid or reduce shortages, relieve stressed sources of water, and find new sources of fresh water.

Lesson 1.5

• drought• drought emergency• drought warning• drought watch

Chapter 1 Watersheds & Wetlands

Final Thoughts ….