ravenna creek is it healthy?. why ravenna creek? urban creek, neighborhood relevance urban creek,...

RavennaRavenna Creek Creek

Is it Healthy?Is it Healthy?

Why Ravenna Creek?Why Ravenna Creek?

Urban creek, neighborhood relevanceUrban creek, neighborhood relevance Accessible to schoolsAccessible to schools Environmental studyEnvironmental study ““Real Science”Real Science” Variety of tests can be preformed Variety of tests can be preformed

Where?Where?

• Starts at Cowen Park and Starts at Cowen Park and finishes at Ravenna Park.finishes at Ravenna Park.

• Creek is fed by several Creek is fed by several springs throughout springs throughout Ravenna Park. Ravenna Park.

• Creek diverted to sewer.Creek diverted to sewer.• Approximate length is Approximate length is

3,500 feet.3,500 feet.

What did we look for?What did we look for?

Physical FeaturesPhysical Features

Cobble embeddedness, consolidation, stream Cobble embeddedness, consolidation, stream flow, qualitative characteristicsflow, qualitative characteristics

Human ImpactHuman Impact Chemical TestsChemical Tests

pH, Dissolved Oxygen, alkalinity, temppH, Dissolved Oxygen, alkalinity, temp Benthic Macroinvertebrate DiversityBenthic Macroinvertebrate Diversity

Initial ModelInitial Model

Human ImpactHuman Impact

On Ravenna CreekOn Ravenna Creek

Why Study Human Involvement?Why Study Human Involvement?

This creek is in an urban area and can demonstrate how This creek is in an urban area and can demonstrate how humans affect the ecosystem.humans affect the ecosystem.

Ravenna creek exists in its current form because of Ravenna creek exists in its current form because of engineering projects and urban development.engineering projects and urban development.

Community groups want to use public money to reverse past Community groups want to use public money to reverse past human impact on the creek.human impact on the creek.

Human Involvement TimelineHuman Involvement Timeline 1911—Green Lake Artificially Lowered, cutting off source of creek1911—Green Lake Artificially Lowered, cutting off source of creek 1948—Creek rerouted into city’s sewer system1948—Creek rerouted into city’s sewer system 1991—Plans are announced to reconnect Ravenna Creek to Lake Washington. 1991—Plans are announced to reconnect Ravenna Creek to Lake Washington.

Local residents propose having the creek flow on the surface “daylighting the Local residents propose having the creek flow on the surface “daylighting the creek” rather than through a pipe.creek” rather than through a pipe.

1993—The community group Ravenna Creek Alliance is formed1993—The community group Ravenna Creek Alliance is formed 1994—Seattle City Council passes a resolution supporting reconnecting the creek 1994—Seattle City Council passes a resolution supporting reconnecting the creek

to the lake and daylighting the connection.to the lake and daylighting the connection. 1997—King County issues $3 million for the project.1997—King County issues $3 million for the project. 1998—Seattle City Hall rejects daylighting in favor of pipe reconnect.1998—Seattle City Hall rejects daylighting in favor of pipe reconnect. 1999—The time limit for federal funding expires.1999—The time limit for federal funding expires. 2003—Plan approved to reconnect the creek to the lake and extend the creek in 2003—Plan approved to reconnect the creek to the lake and extend the creek in

both directions.both directions.

Guiding AssumptionsGuiding Assumptions

1.1. Due to the high use of the park and the urban location of the Due to the high use of the park and the urban location of the stream, the stream will show negative consequences of stream, the stream will show negative consequences of human impact such as polluted water.human impact such as polluted water.

2.2. Polluted water is characterized by low oxygen content, Polluted water is characterized by low oxygen content, abnormal pH, and abnormal alkalinity.abnormal pH, and abnormal alkalinity.

3.3. Polluted water will not contain a diverse population of Polluted water will not contain a diverse population of macro invertebrates.macro invertebrates.

Methods of Data CollectionMethods of Data Collection Data from chemical tests and insect survey were examined to determine the Data from chemical tests and insect survey were examined to determine the

effects of humans on the stream.effects of humans on the stream. Quantitative chemical tests for dissolved oxygen, pH, and alkalinity (the Quantitative chemical tests for dissolved oxygen, pH, and alkalinity (the

tendency to resist a change in pH) were performed at five stream locations.tendency to resist a change in pH) were performed at five stream locations. Insects were collected and identified at three stream locations. Insects were collected and identified at three stream locations. Data directly related to the stream and sewer treatment was obtained via Data directly related to the stream and sewer treatment was obtained via

the internet.the internet.

Reconnecting the CreekReconnecting the Creek

Environmental Concerns:Environmental Concerns: The north fork of the creek appears to be impacted by runoff from the The north fork of the creek appears to be impacted by runoff from the

nearby houses. The pH of this section of the creek is between 8-8.5, higher nearby houses. The pH of this section of the creek is between 8-8.5, higher than the rest of the creek at 7.0-7.5.than the rest of the creek at 7.0-7.5.

After the north fork enters the main creek, the impact appears to be After the north fork enters the main creek, the impact appears to be minimized. PH is normal after the fork.minimized. PH is normal after the fork.

There is no evidence from this study that suggests that the water from the There is no evidence from this study that suggests that the water from the creek is unhealthy and should not enter the lake.creek is unhealthy and should not enter the lake.

The 2 million gallons of fresh water lost to the sewer drain would be The 2 million gallons of fresh water lost to the sewer drain would be beneficial to the ecosystem of the university slough.beneficial to the ecosystem of the university slough.

Reconnecting the CreekReconnecting the Creek

Financial ConcernsFinancial Concerns The west point sewage treatment plant at The west point sewage treatment plant at

discovery park treats about 133 million gallons discovery park treats about 133 million gallons of water daily. Of this, the Ravenna creek drain of water daily. Of this, the Ravenna creek drain contributes @ 2 million gallons.contributes @ 2 million gallons.

The projected budget for treatment from 2002-The projected budget for treatment from 2002-2007 is 90.8 million dollars.2007 is 90.8 million dollars.

At this rate, it should take just over 25 years for At this rate, it should take just over 25 years for the government to save money from the government to save money from reconnecting the stream, given a project cost of reconnecting the stream, given a project cost of 7 million dollars.7 million dollars.

This rough projection is based on the This rough projection is based on the assumption that the cost of treating water is assumption that the cost of treating water is proportional to the volume treated and that these proportional to the volume treated and that these costs will remain fixed.costs will remain fixed.

0

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400

500

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700

0 5 10 15 20 25 30 35

time (years)

cost

(mill

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of d

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rs)

cost nothing

cost reroute

Final ThoughtsFinal Thoughts We often think of human impact as the negative unintentional consequences of We often think of human impact as the negative unintentional consequences of

human activity.human activity. We must also consider the positive and negative effects of intentional human We must also consider the positive and negative effects of intentional human

activity.activity. Ravenna Creek is spring-fed and is not as susceptible to pollution as a strictly Ravenna Creek is spring-fed and is not as susceptible to pollution as a strictly

watershed-based stream.watershed-based stream. Ravenna Creek is a healthy habitat for life and would enrich the ecosystem by Ravenna Creek is a healthy habitat for life and would enrich the ecosystem by

reconnecting to university slough.reconnecting to university slough. The financial benefits of removing the creek from the sewer system would take 25 The financial benefits of removing the creek from the sewer system would take 25

years to materialize.years to materialize.

Physical FeaturesPhysical Features

Ravenna CreekRavenna Creek

What physical features did I measure?

* Cobble embeddedness* Substrate size* Consolidation

1. The stream bottom

2. The stream flow3. General qualitative characteristics* Location of test site* Percent coverage* Other

What do they tell you about the stream’s health?What do they tell you about the stream’s health?

Cobble EmbeddednessCobble Embeddedness

* The extent to which cobbles are surrounded or covered by fine sediment.* Embeddedness can predict what type of species can live in the stream.* Generally, at 30-40%, salmon spawning habitats are lost and macroinvertabrate populations are threatened

Stream FlowStream FlowPollutants and natural Pollutants and natural substances are influenced by substances are influenced by stream flowstream flowFlow affects the amount of Flow affects the amount of DO and the temperatureDO and the temperatureDirectly affects the physical Directly affects the physical features of the streamfeatures of the streamThe amount of sediment and The amount of sediment and debris a stream can carrydebris a stream can carryWhat types of plants and What types of plants and animals live in the streamanimals live in the stream

General Qualitative MeasurementsGeneral Qualitative MeasurementsPercent CoveragePercent CoverageAmount of vegetation and Amount of vegetation and general characteristics of the general characteristics of the plants around the streamplants around the stream

LocationLocationStream flowStream flow

THE BIGASSUMPTIONSASSUMPTIONS

1.1.Ravenna Creek’s health can be accurately Ravenna Creek’s health can be accurately illustrated with only one day of testing the illustrated with only one day of testing the physical features and correlating those physical features and correlating those features with other data. features with other data.

2.2.Our test sites can be accurately used to Our test sites can be accurately used to portray the overall physical features of portray the overall physical features of Ravenna Creek.Ravenna Creek.

3.3.That I was able to make the qualitative That I was able to make the qualitative measurements measurements unbiasedly.unbiasedly.

SITE #1N 47˚ 40.211

W 122˚ 18.097

THE END of the LINETHE GRATE

Embeddedness: 30%Consolidation: Moderately difficult to moveS

ubstrate size

sand < 0.1”sand < 0.1” 20%20%

gravel 0.1 - 2”gravel 0.1 - 2” 30%30%

cobble 2-10”cobble 2-10” 40%40%

boulder > 10” boulder > 10” --

Percent Coverage: 10%

SITE #2N 47˚ 40.308

W 122˚ 18.217

THE MIDDLE of the ROADTHE BRIDGE

Embeddedness: 40%Consolidation: Loose

Substrate size:0%0%

sand < 0.1”sand < 0.1” 40%40%

gravel 0.1 - 2”gravel 0.1 - 2” 30%30%

cobble 2-10”cobble 2-10” 30%30%



SITE #3N 47˚ 40.313

W 122˚ 18.227

Ravenna Creek’s BuddyTHE TRIBUTARY

Embeddedness: 100%Consolidation: Extremely loose

Substrate size:

silt, clay, mudsilt, clay, mud 100%100%

sand < 0.1”sand < 0.1” 100%100%

gravel 0.1 - 2”gravel 0.1 - 2” --

cobble 2-10”cobble 2-10” --



SITE #4N 47˚ 40.299

W 122˚ 18.446

ANOTHER SITETHE HOLE in the FENCE

Embeddedness: 30%Consolidation: Moderately

difficult to move

sand < 0.1”sand < 0.1” 10%10%

gravel 0.1 - 2”gravel 0.1 - 2” 30%30%

cobble 2-10”cobble 2-10” 60%60%



SITE #5N 47˚ 40.370

W 122˚ 18.726

THE BEGINNINGTHE SPRING

Embeddedness: 100%Consolidation: Very LooseS

ubstrate size:

silt, clay, mudsilt, clay, mud 100%100%

sand < 0.1”sand < 0.1” --

gravel 0.1 - 2”gravel 0.1 - 2” --

cobble 2-10”cobble 2-10” --



1.1.Testing the stream at only one time during the year Testing the stream at only one time during the year makes it difficult to come to a solid conclusion of the makes it difficult to come to a solid conclusion of the stream’s physical features.stream’s physical features.

2.2.The amount of embeddedness in the main stream are The amount of embeddedness in the main stream are at levels that threaten macroinvertebrate populations. at levels that threaten macroinvertebrate populations.

3.3.It is difficult to make qualitative measurements and It is difficult to make qualitative measurements and not be biased.not be biased.

4.4.Without data from experiments testing different Without data from experiments testing different aspects of the stream it is difficult to come to a aspects of the stream it is difficult to come to a concrete conclusion about the stream’s health.concrete conclusion about the stream’s health.

THE BIGCONCLUSIONS

HOW HEALTHY IS HOW HEALTHY IS RAVENNA CREEK?RAVENNA CREEK?

Let’s find out…

Revised ModelRevised Model

Water Quality of the Creek

pH Levels (6.5-8.0)

Low oxygen Levels

TemperatureAlkalinity

High levels

pH Levels below 6.5 or above 8.0

Low levels

High oxygen Levels

Warm water

Cold water

HEALTHY

UNHEALTHY

Benthic MacroinvertebratesBenthic Macroinvertebrates

Ravenna Creek and the Spineless Ravenna Creek and the Spineless OnesOnes

What is a BMI?What is a BMI?

Bethinc–-on the bottomBethinc–-on the bottom

Macro—Big(ish)Macro—Big(ish)

Invertebrate—no spineInvertebrate—no spine

Benthic Macroinvertebrates are animals with no Benthic Macroinvertebrates are animals with no backbone that are visible to the naked eye. backbone that are visible to the naked eye. Includes: Insects, worms, mollusks, Includes: Insects, worms, mollusks, crustaceans and arachnids crustaceans and arachnids

BMI’s as Indicators of Stream BMI’s as Indicators of Stream HealthHealth

BMI’s are important links in the food chain as BMI’s are important links in the food chain as recyclers of nutrients and food for fishrecyclers of nutrients and food for fish

As fairly sedentary beasties, they are “stuck” As fairly sedentary beasties, they are “stuck” in the polluted water or sedimentin the polluted water or sediment

They are good indicators. Different BMI’s They are good indicators. Different BMI’s have different life requirements, some are have different life requirements, some are more or less tolerant to pollution: think canary more or less tolerant to pollution: think canary in a coal minein a coal mine

BMI’s as Indicators of Stream BMI’s as Indicators of Stream Health cont.Health cont.

Short life spans make problems readily Short life spans make problems readily detectabledetectable

BMI’s are easier to ID than algaeBMI’s are easier to ID than algae

Model of BMI’s and Stream Model of BMI’s and Stream HealthHealth

Diversity of BMI’s

Good health

Poor health

When you ASSUME you make an When you ASSUME you make an ASS out of U and MEASS out of U and ME

Collection sites chosen were representative of Collection sites chosen were representative of the stream at largethe stream at large

That sampling on two separate days caused That sampling on two separate days caused negligible difference in what we foundnegligible difference in what we found

That we indeed found everything to be found That we indeed found everything to be found in the samplesin the samples

That our ID powers were accurateThat our ID powers were accurate

Materials and MethodsMaterials and Methods

Macroinvertebrate Survey, Macroinvertebrate Survey, Field Procedure from Field Procedure from Adopt-a-Stream Adopt-a-Stream Foundation’s Foundation’s Streamkeeper’s Field GuideStreamkeeper’s Field Guide

Used a Kick Net to collect Used a Kick Net to collect samples from 3 locations samples from 3 locations along Ravenna Creek: one along Ravenna Creek: one before the tributary, one at before the tributary, one at the junction and one after the junction and one after (corresponds to sites 1,2 and (corresponds to sites 1,2 and 4)4)

Materials and Methods cont.Materials and Methods cont.

Collected BMI’s by Collected BMI’s by visually sorting through visually sorting through sediment and leaf littersediment and leaf litter

Used key provided in Used key provided in Streamkeeper’s Field Streamkeeper’s Field Guide Guide to identify to identify specimens to order specimens to order

Within order we Within order we identified feeding group: identified feeding group: scraper, collector, scraper, collector, predator, filterer or predator, filterer or shreddershredder

ResultsResults

Order DiversityOrder Diversity Feeding DiversityFeeding Diversity EPT RichnessEPT Richness

Meet the BMI’sMeet the BMI’s

Caddisfly

Midge

Stonefly

Mayfly

Scud/Amphipod

Order DiversityOrder DiversitySite 1 Diversity

0

1

2

3

Taxa

# of taxa

Site 2 Diversity

0

1

2

3

Taxa

# of taxa

Site 1 has lowest diversity, Site 2 the highestSite 1 has lowest diversity, Site 2 the highest All three sites show wide range of different BMI’sAll three sites show wide range of different BMI’s Higher BMI diversity suggests healthier streamHigher BMI diversity suggests healthier stream

Site 3 Diversity

0

1

2

3

Taxa

# of taxa

Feeding StrategiesFeeding Strategies

Midge Filtering Mouthparts

Predatory Stonefly Mouthparts

Snail radula (scraper)

Feeding Group DiversityFeeding Group DiversitySite 1 Feeding Type Diversity

0

1

2

3

Feeding Type

# of taxa

Site 2 Feeding Type Diversity

0

1

2

3

Feeding Type

# of taxa

Site 1 has lowest diversity, sites 2 and 3 had similar Site 1 has lowest diversity, sites 2 and 3 had similar resultsresults

More feeding type diversity indicates more variety of More feeding type diversity indicates more variety of available food sources which suggests better stream available food sources which suggests better stream healthhealth

Site 3 Feeding Type Diversity

0

1

2

3

Feeding Type

# of taxa

EPT RichnessEPT Richness

EPT stands for EPT stands for Ephemeroptera, Ephemeroptera, Plecoptera and Plecoptera and Tricoptera, the order Tricoptera, the order Names of May, Stone Names of May, Stone and Caddisfiesand Caddisfies

These are the most These are the most

sensitive to pollutionsensitive to pollution

EPT Richness

0

1

2

3

4

5

Site 1 Site 2 Site 3

EPT Richness

Macroinvertebrate taxa in other Macroinvertebrate taxa in other Puget Sound Creeks.Puget Sound Creeks.

Fore, L. S. et. Al (2001)

Less developed More developed

Holder Rock Evans Soos Kelsey Thornton Pipers

Ravenna

ConclusionsConclusions

Data shows wide diversity of taxa and feeding Data shows wide diversity of taxa and feeding strategies which suggests a healthy streamstrategies which suggests a healthy stream

Average EPT diversity of 3.66 is lower than Average EPT diversity of 3.66 is lower than Streamkeeper’s Field Guide value for “good Streamkeeper’s Field Guide value for “good health” at 8-12health” at 8-12

Ravenna Creek is moderately healthy for an Ravenna Creek is moderately healthy for an urban stream.urban stream.

How to make the results relevant to How to make the results relevant to science science

The stream is smallThe stream is small We sampled in the fallWe sampled in the fall

Classroom ApplicationClassroom Application

All tasks were appropriate for a science class for All tasks were appropriate for a science class for middle school or high school. middle school or high school.

The tasks range in patience, skills, potential interests, The tasks range in patience, skills, potential interests, potential dirtiness, and ability to “rough it.”potential dirtiness, and ability to “rough it.”

Ideally do this in early fall and/or spring.Ideally do this in early fall and/or spring. Background information of scientific concepts Background information of scientific concepts

needed to understand data.needed to understand data. Teacher needs to have the resources and procedures Teacher needs to have the resources and procedures

necessary to help students collect data.necessary to help students collect data.

Effectiveness as an inquiry projectEffectiveness as an inquiry project

Specific directions to determine Specific directions to determine measurements: pH, bug identification, stream measurements: pH, bug identification, stream flow, etc.flow, etc.

The overall question, “Is Ravenna Creek The overall question, “Is Ravenna Creek healthy?” leads to lots of factors that could be healthy?” leads to lots of factors that could be investigated to determine the health. investigated to determine the health.

Community activism: opportunity to present Community activism: opportunity to present information to a committee, be involved in the information to a committee, be involved in the community, etc.community, etc.

ravenna creek is it healthy?. why ravenna creek? urban creek, neighborhood relevance urban creek,...

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