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Analysis of Water Chemistry

Urban Stream Restoration Project

By:

Bob Smith &

Shelly Alicia

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Outline

Water Chemistry Background

Chemistry in Urban Streams

Methods

2003 Results

Comparison to 2002 Conclusions

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Outline

Water Chemistry Background

Chemistry in Urban Streams

Methods

2003 Results

Comparison to 2002 Conclusions

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Temperature

Most aquatic organisms are cold-blooded

and have an ideal temperature range,

specific to the organism:

Diatoms 15-25 degrees C

Green algae 25-35 degrees C

Blue greens 30-40 degrees C

Salmonidscold water fish

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Temperature, continued

Affects development of invertebrates,metabolism of organisms

Affects dissolved oxygen (warm waterholds less oxygen)

Warm water makes some substances more

toxic (cyanide, phenol, xylene, zinc) and, ifcombined with low DO, they become evenmore toxic

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Dissolved Oxygen

Oxygen that is dissolved in water

DO increases with cooler water and mixing of

water through riffles, storms, wind Nutrient loading can lead to algal blooms which

result in decreased DO

4-5 ppm DO is the minimum that will supportlarge, diverse fish populations. Ideal DO is 9

ppm. Below 3 ppm, all fish die.

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Dissolved Oxygen, continued

Dissolved oxygen can also be expressed as

% saturation

80-124% = excellent

60-79% = ok

< 60% = poor

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Conductivity

Measures the ability of water to carry anelectric current

Measures the ions such as Na+, Cl- in thewater

Differences in conductivity are usually due

to the concentration of charged ions insolution (and ionic composition, temp.)

Reported as microsiemens per cm

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pH

pH measures the degree of acidity or alkalinity of

the water (each number is a 10-fold difference)

0-6 = acid; 7 = neutral; 8-14 = base Ideal for fish = 6.58.2

Ideal for algae = 7.58.4

Acid waters make toxic chemicals (Al, Pb, Hg)more toxic than normal, and alter trophic structure

(few plants, algae)

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Turbidity

Measures the cloudiness of the water

Turbidity caused by plankton, chemicals,silt, etc.

Most common causes of excess turbidity areplankton and soil erosion (due to logging,mining, farming, construction)

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Turbidity, continued

Excess Turbidity can be a problem:

Light cant penetrate through the water

photosynthesis may be reduced or even stopalgae can die

Turbidity can clog gills of fish and shellfish

can be fatal Fish cannot see to find food, but can hidebetter from predators

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Phosphorus (Reactive)

Is necessary for plant and animal growth

Natural source = phosphate-containing

rocks

Anthropogenic source = fertilizer and

pesticide runoff from farming

Can stimulate algal growth/bloom

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Nitrates

Formed by the process of nitrification (addition ofO2 to NH3by bacteria)

Used by plants and algae Is mildly toxic, fatal at high doses

Large amounts (leaking sewer pipes, fertilizerrunoff, etc.) can lead to algal blooms, which can

alter community structure, trophic interactions andDO regimes)

Below 90 mg/L seems to have no effect on warmwater fish, but cold water fish are sensitive

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Alkalinity

A measure of the substances in water that

can neutralize acid and resist changes in pH

Natural source = rocks

Ideal water for fish and aquatic organisms

has a total alkalinity of 100-120 mg/L

Groundwater has higher alkalinity than

surface water

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Hardness

The amount of Calcium and Magnesium inthe water (the two minerals mostly

responsible)

Natural source = rocks

Limestone = hard water, granite = not hardwater

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Hardness, continued

Soft water can be a problem: in soft water, heavymetals are more poisonous, some chemicals aremore toxic, drinking soft water over long periodscan increase chance of heart attack

060 = soft water

61-120 = moderately hard water

121-180 = hard water 181+ = very hard water

Hardness and alkalinity are related

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Outline

Water Chemistry Background

Chemistry in Urban Streams

Methods

2003 Results

Comparison to 2002 Conclusions

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Physical Effects of Urbanization

Related to Water Chemistry Riparian Vegetation Removal

Decreased Groundwater Recharge

Heat Island Effect

Increased Surface Runoff / Impervious

Surfaces

Leaky Storm-water / Sewage Pipes

Point Source Pollution

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Trends in Water Chemistry

Temperature increases

Nitrate increases

Phosphorus increases

Conductivity increases (Increased ion

concentration)

O2 demand increases

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Outline

Water Chemistry Background

Chemistry in Urban Streams

Methods

2003 Results

Comparison to 2002 Conclusions

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Field Measurements

Dissolved Oxygen

Temperature Conductivity

pH

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Water Collection For Laboratory

Analysis Grab Samples

Three replicates

(from multiplesamples)

Measured within

24 hours (fewexceptions)

Picture Source: http://www.ci.gresham.or.us/

departments/des/stormwater/water_quality.htm

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Laboratory Analysis

Nitrate

Reactive

Phosphorus

Alkalinity

Hardness

Turbidity

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Outline

Chemistry in Urban Streams

Water Chemistry Measurements and Theory

Methods

2003 Results

Comparison to 2002 Conclusions

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Field Measurements 2003

Temperature (oC)

0

5

10

15

20

1 2 3

Dissolved Oxygen (mg/L)

0

5

10

15

1 2 3

Conductivity (u s)

0

200

400

600

800

1 2 3

pH

5

5.5

6

6.5

7

7.5

1 2 3

SAL PB

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Turbidity

All values for 2003

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Reactive Phosphorus 2003

0

0.05

0.1

0.15

0.2

0.25

1 2 3Sampling Date

mg/L

PB SAL

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Nitrate 2003

0

0.5

1

1.5

2

2.5

1 2 3Sampling Date

mg/L

**

PB SAL

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Alkalinity 2003

0

5

10

15

20

25

30

35

40

45

1 2 3Sampling Date

mgCaCO

3/L

***

PB SAL

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Hardness 2003

0

2

4

6

8

10

12

1 2 3

Sampling Date

g.d.h

.

*

**

PB SAL

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Outline

Chemistry in Urban Streams

Water Chemistry Measurements and Theory

Methods

2003 Results

Comparison to 2002 Conclusions

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Field Measurement PB

Dissolved Oxygen (mg/L)

0

5

10

15

1 2 3

Conductivity (u s)

0

50

100

150

1 2 3

pH

5

5.5

6

6.5

7

7.5

1 2 3

Temperature (

o

C)

0

5

10

15

20

1 2 3

2002 2003

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Field Measurement For SALDissolved Oxygen (mg/L)

0

2

4

6

8

10

12

14

1 2 3

Temperature (oC)

0

5

10

15

20

1 2 3

Conductivity (u s)

0

200

400

600

800

1 2 3

pH

6.6

6.7

6.86.9

7

7.1

7.2

1 2 3

2002 2003

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Paint Branch

Reactive Phosphorus (mg/L)

0

0.1

0.2

0.3

0.4

0.5

1 2 3

Nitrate (mg/L)

0

0.5

1

1.5

2

2.5

1 2 3

Alkalinity (mg CaCO3/L)

0

5

10

15

20

1 2 3

Hardness (g.d.h.)

0

0.5

1

1.5

2

1 2 3

2002 2003

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Stewart April LaneReactive Phosphorus (mg/L)

0

0.2

0.4

0.6

0.8

1

1.2

1 2 3

Nitrate (mg/L)

0

0.5

1

1.5

2

2.5

1 2 3

Alkalinity (mg CaCO3/L)

0

10

20

30

40

50

60

1 2 3

Hardness (g.d.h.)

0

2

4

6

8

10

12

1 2 3

2002 2003

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Outline

Chemistry in Urban Streams

Water Chemistry Measurements and Theory

Methods

2003 Results

Comparison to 2002

Conclusions

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Between Site Differences

Land useincreased runoff cause increasedinput of particular constituents

Natural site variationSubstrate type

Between Years

Increased snow caused more runoff

increased use of road-salt Drought (temperature, DO)

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. . . Rivers and the inhabitants ofthe watery element were made

for wise men to contemplate, andfools to pass by withoutconsideration, . . . for you may

note, that the waters areNatures storehouse, in whichshe locks up her wonders.

Izaak Walton

(from Ward, 1992)