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Note to Educator

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Fundamental Concepts

This slide show has explanatory notes to accompany each slide.
Its primary purpose is to provide background for you, the educator, to make it easier to introduce the fundamental concepts to your students.
Be sure to review the PowerPoint prior to sharing it with your students and consider using some of the videos listed on the Watershed Game website as alternatives.
Note: In accordance with the Americans with Disabilities Act, this material is available in alternative formats upon request. Direct requests to 612-624-7708.

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Coast Model

Fundamental Concepts Science Background

The science you need to understand before you play the game.

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Fundamental Concepts

What you need to know before playing the game:

Definitions:

watersheds
Stormwater
Impervious surfaces
floodplains
resilience to flooding
nonpoint source pollution

Types, sources, and impacts of nonpoint source water pollution from excess sediment, nitrogen and phosphorus
Impacts of excessive flooding on coastal lands and infrastructure
Factors that make areas more likely to be damaged by flooding

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Fundamental Concepts

Definition of a watershed

A watershed is the area of land that drains to a particular lake, wetland or stream.

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Undeveloped Watershed: �What happens when it rains?

Forested wetland

Bog

50%

10%

40%

Fundamental Concepts

Definition of stormwater

Slow and steady!

This is a demonstration of a natural, undeveloped watershed (NOTE: It is an animated slide – each numbered explanation below represents one click of the mouse).

Natural, undeveloped watersheds have natural ways to use, store, and filter rainfall.

In a watershed that remains covered with natural vegetation (including forests, wetlands, streams and lakes, grasslands) most of the rainfall that hits the land is slowly:

Soaked up by vegetation to support growth, with some of it evaporating back into the atmosphere
What water does enter the soil gets filtered by natural soil processes as it soaks into the ground, helping to “lock up” excess phosphorus, sediment and other substances
This water then becomes the groundwater that helps keep many lakes and streams cooler in the summer.

Another way the land soaks up water is by storing it in wetlands like the forested wetland and bog in the picture. Wetlands act as sponges, holding water temporarily.

This gradual process, in which much of the water soaks back into the ground, is removed by vegetation, or is stored in wetlands helps protect the land from erosion or flooding.

In naturally-vegetated watersheds, studies show that roughly 50% of a typical rainfall soaks into the ground and about 40% ends up back in the atmosphere or supporting vegetative growth, leaving only about 10 % of the rainfall flowing slowly across the land.

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Developed Watershed: �What happens when it rains?

Forested wetland

Bog

50%

10%

40%

Fundamental Concepts

Definition of stormwater

This is a demonstration of a developed watershed (NOTE: It is an animated slide – each numbered explanation below represents one click of the mouse).

This is the same watershed we looked at before, but now with a farm, city, and parking lots where there used to be trees and wetlands.

Now when rain hits the the urban area and flows across the parking lots and exposed soils of the farm, much less of it soaks back into the ground or gets stored in wetlands.

Because there is more water staying on the land surface and because there is less vegetation to soak it up, there is much more water flowing much more quickly across the land.
This quickly moving water takes exposed soil, fertilizer, pollutants, and other unwelcome materials to the watershed’s lakes, wetlands, and streams.

AND all that water moving so quickly can cause flooding. Note that the lake in the slide has been flooded, covering up the little shoreline cabins.

Because so much water stays on the land surface, much less is filtered through the soil to resupply the groundwater.
The surface water flowing across parking lots and rooftops can be heated by the sun, resulting in lakes and streams that are too warm.

In developed watersheds with a mixture of land uses, studies show that about 50% of typical rainfalls flows quickly over the land, with only about 10% soaking into the ground.

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Nutrients and Bacteria

Water Flows Too Fast

Too Much Water

Erosion

Sediment

Road Salt and other Pollutants

Fundamental Concepts

Definition of nonpoint source pollution

Developed Land: Many Impacts

Nonpoint source pollution (NPS): Rainfall or snowmelt moving over and through the ground picks up and carries pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters and groundwater.

Potential impacts from human activities on the land: new photo credit river keeper.

The Watershed Game only focuses on sediment (from erosion) and the nutrient phosphorus, but there are many other pollutants and problems that can result from the way we use the land.

Water Flows Too Fast: Water flowing too fast can erode soil, uproot plants, and change fish and invertebrate habitat.
Too Much Water: Too much water, in the form of flooding, causes property damage and changes habitat.
Nutrients and Bacteria: Runoff over lands and hard surfaces impacted by fertilizers, human or animal waste, and other sources can contribute excess nutrients (primarily nitrogen and phosphorus) and potentially harmful bacteria to waterways.
Road Salt and Other Pollutants: Pollutants, including road salt, gasoline, metals, and other substances deposited on hard surfaces, such as roadways, can be flushed into local waterways.
Erosion: Large volumes of quickly moving water can erode sensitive lands and stream and lake banks.
Sediment: Sediment from erosion, road and other construction, and other sources can impact waterways and smother habitat.

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Eroded upland soil
Streambank erosion
Atmospheric dust

Fertilizer
Human and animal waste
Streambank erosion
Organic industry wastes
Decaying plants

Excess Sediment

Excess Phosphorus

Fundamental Concepts

oars3rivers.org/sites/default/files/images/biomass_survey-b.jpg

Sources of Pollutants

Fertilizer
Human and animal waste
Urban runoff
Atmospheric deposition

Excess Nitrogen

So when are sediment, nitrogen, and phosphorus pollutants?

Sediment and nutrienta are pollutants when they are entering water bodies in much higher concentrations than would happen naturally in an undeveloped watershed.

Where do they come from?

Sediment: When we talk about sediment, we are referring to fine soil and sand that enters water bodies from erosion in the watershed.
Nutrients: The two main nutrients we are concerned about are nitrogen and phosphorus.

Excess phosphorus is contributed mainly through fertilizer and human and animal waste.
Excess nitrogen comes from human and animal waste, urban runoff, fertilizer, and atmospheric deposition.

Sources of excess phosphorus to surface waters:

Agricultural fertilizers
Manure
sewage treatment plants and septic systems,
Organic wastes in industrial discharges
runoff from urban areas and construction sites,
stream bank erosion.
decaying plant material

Sources of excess nitrogen to waters include:

· livestock and poultry feedlots

· municipal sewage effluents

· industrial wastewater effluents

· mineralization of soil organic matter

· cultivation of n-fixing crop species

· use of animal manure and inorganic N fertilizers, and subsequent runoff/leaching/drainage

· runoff from standing or burned forests and grasslands

· urban and suburban runoff

· septic system leachate, and discharges from failed septic systems

· emissions to the atmosphere from volatilization of manure and fertilizers and combustion of fossil fuels, and the subsequent atmospheric (wet and dry) deposition into surface waters

· other activities that can mobilize N (from long-term storage pools) such as biomass burning, land clearing and conversion, and wetland drainage

Source: Nitrogen in Minnesota Surface Waters • June 2013 Minnesota Pollution Control Agency A2-18. https://www.pca.state.mn.us/sites/default/files/wq-s6-26a2.pdf.

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Phosphorus

Sticks to sediment particles – moves with sediment
Key nutrient to reduce to control algae in many inland waters (phosphate)

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PO₄³⁻

Sediment

NO₃⁻

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Fundamental Concepts

Excess Nutrients

Nitrogen

Nitrogen is soluble in water and goes wherever water goes, including groundwater (nitrate)
Key nutrient to reduce to control algae in many coastal waters

NO₃⁻

Phosphorus as a pollutant

Phosphorus is sticky. It sticks to soil particles.

Think of the ball in the picture above as being the phosphate molecule and the Velcro paddles as being the soil particles.

The molecular form that phosphorus takes in water binds easily to clays and other soil particles that make up sediment.
This is important because any time that sediment is getting into waterways it also will have phosphorus hitchhiking along.

Controlling excess sediment and keeping it away from lakes, wetlands, and streams also helps reduce excess phosphorus.
Too much phosphorus is like providing a banquet table for aquatic plants and algae and can lead to excessive growth.

Though nitrogen is also needed for plant growth, it is usually more plentiful than phosphorus in freshwaters in the Midwest. The opposite is often true in some nutrient poor lakes and in coastal waters.

It doesn’t take much phosphorus to cause a lot of green stuff to grow in waterways.

1 pound phosphorus = 500 pounds algae.

Nitrate (NO3) is very soluble in water and is negatively charged, and therefore moves readily with soil water through the soil profile, where it can reach subsurface tile lines or groundwater. Where groundwater remains oxygenated, nitrate remains stable and can travel in the groundwater until it reaches surface waters. Similarly, nitrate can move downward into tile lines, which then route the drained water to ditches and surface waters. When nitrate encounters low oxygen/anoxic conditions in soils or groundwater it may be transformed to N gasses through a biochemical process called “denitrification.” Therefore, groundwater nitrate is sometimes lost to gaseous N before the nitrate impacted groundwater has enough time to travel to and discharge into streams. Typically, a smaller fraction of nitrate reaches streams in stormwater runoff over the land surface, as compared to subsurface pathways.

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Some impacts

Too much aquatic plant and/or algae growth
Harmful Algal Blooms or HABs
Loss of water clarity
Low dissolved oxygen
Loss of habitat and aquatic life
Can result in water that is not swimmable, drinkable, or fishable

Too much nutrients:

Fundamental Concepts

Excess Nutrients: Impacts to the Coast

More about impacts of excess nutrients:

There is a name for the addition of excess nutrients to lakes or rivers that leads to excess plant growth. The process is called eutrophication.
Common symptoms of eutrophication include:

Too much plant and algae growth (some types of algae that do well in eutrophic conditions can be toxic to humans and animals)
Loss of water clarity caused by algae
Low dissolved oxygen caused by decomposing plant and animal matter and by plant respiration
Loss of habitat and aquatic life
Water that is not swimmable, drinkable, or fishable

Don’t forget about excess nitrogen! It can be important, especially in low nutrient lakes. Lawn fertilizer may be very high in nitrogen and runs off the land easily. Too much nitrogen can affect shoreline plant species and increase susceptibility to nuisance plant species.

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Too much sediment:

Some impacts

Absorbs more heat from the sun, thus increasing water temperatures.
Reduces water clarity and light penetration, making it hard for visual feeders like fish to find food and reducing aquatic plant photosynthesis.
Brings phosphorus with it, (and some nitrogen), increasing algae.
Reduces habitat near shore for fish and “fish food” like aquatic insects.

Fundamental Concepts

Excess Sediment: Impacts to the Coast

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Too much sediment reduces:

Fish habitat

shelter
spawning areas
egg incubation areas

Insect habitat

Very good

William Taft, MI DNR

Very Good

Poor

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Fundamental Concepts

Excess Sediment: Impacts to the Coast

Sediment embedded on the lake, stream, or river bottom:

Excess eroded sediment degrades habitat in the following ways:

Settling sediment can bury and suffocate fish eggs and bury the gravel nests they rest in as well as reduce habitat for many stream invertebrates that fish feed on.
Suspended sediment in high concentrations irritates the gills of fish and can cause death.
Suspended sediment in high concentrations can dislodge plants, invertebrates, and insects in the stream bed. This affects the food source of fish and can result in smaller and fewer fish.
Sediment can destroy the protective mucous covering the eyes and scales of fish, making them more susceptible to infection and disease.
Excess sediment from eroding soils contains organic matter that contributes to oxygen depletion in the water as it is decomposed.
Eroding soils also contribute the nutrients phosphorus and, to a lesser degree, nitrogen. In low nutrient streams and recovering waters these can contribute to algal growth and oxygen depletion.
Sediment may carry toxic agricultural and industrial compounds such as heavy metals and pesticides. If these are released into the water they can cause abnormalities or death in the fish.
Sediment loads in waterways often result in further increased erosion and instability of streambanks, causing stream channels to become wider and shallower, which leads to warmer water temperature.

Source: https://www.waterontheweb.org/under/waterquality/sediment.html

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Fundamental Concepts

What is a floodplain?

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https://oceanservice.noaa.gov/facts/resilience.html

Proactive:

Building the ability of a community to "bounce back" after hazardous events such as hurricanes, flooding, and coastal storms.

Rather than reactive.
Why?

Informed, prepared communities can rebound more quickly from weather and climate-related events.
Resilient communities can reduce negative health, environmental, and economic impacts.

More flooding is occurring in the Mississippi River Valley, Midwest, and Northeast
U.S. coastal flooding has doubled in a matter of decades.

Fundamental Concepts

Union of Concerned Scientists: https://www.ucsusa.org/sites/default/files/attach/2018/07/gw-fact-sheet-epif.pdf

Coastal Resilience to Flooding

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Benefits of flooding:

Recharging groundwater
Increasing fish production
Creating wildlife habitat
Recharging wetlands
Constructing floodplains
Rejuvenating soil fertility

Severe floods can cause:

Accelerated erosion
More nutrient runoff and mobilization
Disrupted drainage systems
Spills of raw sewage and animal waste
Discharges of toxic substances from industrial, agricultural, and urban areas

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Fundamental Concepts

Coastal Resilience to Flooding

Flooding is natural!

BUT severe floods can impact water quality!

Biogeochemistry (2018) 141:439-461

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