The Urban WatershedThe Urban Watershed

Unit 1, Topic 1Unit 1, Topic 1

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Urban vs. Suburban vs. Rural

Urban vs. Suburban vs. Rural

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The value of vegetationThe value of vegetation» Ecosystem services

» Oxygen production» Pollution absorption» Natural cooling» Erosion control» Wildlife habitats» Aesthetic value

4

Heat island effectHeat island effect

© censam.mit.edu

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Air pollutionAir pollution

» Urban areas have higher levels than rural areas, why?» Increased combustion» Industrial processes» Development» Tall buildings» Less vegetation

» How could cities reduce local air pollution?

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Impervious surfaces and water

Impervious surfaces and water

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WatershedsWatersheds© NJ Water Supply Association

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What is water quality?What is water quality?

Assessment based on abiotic and biotic parameters

Reflects land use activities and air quality in the watershed

Assessment based on abiotic and biotic parameters

Reflects land use activities and air quality in the watershed

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What can be in the water?What can be in the water?

Point source pollutants

Point source pollutants

Non-point source pollutants

Non-point source pollutants

SewageIndustrial wasteOil spills

Agricultural wasteSewageLitterHousehold chemicalsOil and gasolineIndustrial particulatesAir pollutionPesticides, herbicides, etc…Lawn fertilizers

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Land use and water qualityLand use and water quality

Abiotic water quality parameters

Abiotic water quality parameters

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Dissolved oxygenDissolved oxygenDissolved oxygenDissolved oxygenmeasure of how much oxygen gas is dissolved in a body of water

Measured in parts per million (ppm)1 ppm = 1 milligram of substance (mg) dissolved in 1 liter (l) of water

measure of how much oxygen gas is dissolved in a body of water

Measured in parts per million (ppm)1 ppm = 1 milligram of substance (mg) dissolved in 1 liter (l) of water

>6.0 ppm: lots of animals can survive in the water

<4.0 ppm: animals begin to stress out, bigger that require more oxygen may begin to die

<2.0 ppm: animals cannot survive for more than a short period

1313

Factors that affect DOFactors that affect DO

Oxygen demanding wastes Plant nutrients Turbulence Turbidity Temperature

Oxygen demanding wastes Plant nutrients Turbulence Turbidity Temperature

1414

TemperatureTemperature Varies by season and time of day Affected by surrounding landscape Organisms have temperature tolerance ranges

Temperature affects metabolic rates and DO levels

Varies by season and time of day Affected by surrounding landscape Organisms have temperature tolerance ranges

Temperature affects metabolic rates and DO levels

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pHpHpHpH

measure of the acidity or alkalinity of a liquid

pH scale ranges from 0 (most acidic) to 14 (most basic); 7 is completely neutral, pure water (H2O)

What can extreme pH levels do to proteins?

Most organisms have an optimal pH range of 6.5-8

measure of the acidity or alkalinity of a liquid

pH scale ranges from 0 (most acidic) to 14 (most basic); 7 is completely neutral, pure water (H2O)

What can extreme pH levels do to proteins?

Most organisms have an optimal pH range of 6.5-8

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Aquatic acidificationAquatic acidification

Results in decreased biodiversity Results in decreased biodiversity

Sources: Acid deposition

Sources: Acid deposition

Sulfur based Nitrogen based

Sulfur based Nitrogen based

Industrial and mining discharge Industrial and mining discharge

Organic acid from logging and landfills Organic acid from logging and landfills

How can acidification be avoided? How can acidification be avoided?

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Alkalinity Alkalinity

Measure of the buffering capacity

Carbonate, bicarbonate, hydroxide concentrationslimestone

Measure of the buffering capacity

Carbonate, bicarbonate, hydroxide concentrationslimestone

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Nitrate (NONitrate (NO33--))Nitrate (NONitrate (NO33--))

Naturally occurring nitrogen-containing nutrient needed by plants

Naturally occurring nitrogen-containing nutrient needed by plants

Aquatic nitrogen cycle

1919

Phosphate (PO43-)Phosphate (PO43-)

Naturally occurring phosphorus nutrient needed by plants

Usually a limiting factor for plant growth

Naturally occurring phosphorus nutrient needed by plants

Usually a limiting factor for plant growth

2020

Nitrate and phosphate pollution

Nitrate and phosphate pollution

Human activities add nitrates and phosphates to aquatic systems (cultural eutrophication)

These act as fertilizers and result in "blooms" of algae

This starts a process that may end in a mass die-off of animal life.

Human activities add nitrates and phosphates to aquatic systems (cultural eutrophication)

These act as fertilizers and result in "blooms" of algae

This starts a process that may end in a mass die-off of animal life.

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Mass die-off of fish in Narragansett Bay due to anoxia.

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ChlorideChloride

Toxic to freshwater organisms at higher than natural levelsWhy? (hint: think back to BIO I Honor tonicity lab)

How does excess salt get into fresh water bodies?

Toxic to freshwater organisms at higher than natural levelsWhy? (hint: think back to BIO I Honor tonicity lab)

How does excess salt get into fresh water bodies?

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When is water quality at risk?

When is water quality at risk?

DO < 5 ppm or mg/L pH < 6.5 Nitrate >1.0 ppm Phosphate > 0.1 ppm Chloride > 1000 ppm (1 ppt…point of reference the ocean averages 34 ppt)

DO < 5 ppm or mg/L pH < 6.5 Nitrate >1.0 ppm Phosphate > 0.1 ppm Chloride > 1000 ppm (1 ppt…point of reference the ocean averages 34 ppt)