Karen DuBose

1
Water Reuse in Corvallis A model of public
acceptance

• Karen DuBose
• March 11, 2009

2
The Situation

• Corvallis wastewater treatment plant will exceed
  its TMDL water quality requirements as the city
  grows

• Wastewater recycling is an excellent solution
• No need to discharge into the river
• Advances the citys sustainability ethic

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Goals of this study

• Discover what factors influence the public
  acceptance of water reuse in Corvallis
• Make recommendations to the city about how to
  pursue a wastewater recycling project

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Factors that have been found to influence public
opinion

• Age
• Gender
• Education
• Income
• Occupation
• Length of residence
• Degree of contact
• Prior knowledge of water reuse

• Awareness of water problems
• Presence of children
• Trust in local public utility
• Health effects
• Environmental effects
• Cost of project
• Public opinion of reuse

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Methods

• December 2008 survey of registered voters, 46
  response rate
• 19 questions, six were demographic
• Multiple linear regression

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A model of public acceptance in Corvallis

• Acceptance ß0 ß1(Informed) ß2(Knowledge)
• ß3(Aware)
  ß4(Sustainability) ß5(Trust)
• ß6(Gender) ß7(Age)
  ß8(Children present)
• ß9(Education)

• Dummy variables knowledge, aware, gender, age,
  children present

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Measuring knowledge
Q-4 For the following terms, please indicate if you know what the term means, have heard of the term but dont know its meaning, or have not heard of the term at all. For the following terms, please indicate if you know what the term means, have heard of the term but dont know its meaning, or have not heard of the term at all. For the following terms, please indicate if you know what the term means, have heard of the term but dont know its meaning, or have not heard of the term at all. For the following terms, please indicate if you know what the term means, have heard of the term but dont know its meaning, or have not heard of the term at all. For the following terms, please indicate if you know what the term means, have heard of the term but dont know its meaning, or have not heard of the term at all.
Have not heard of the term at all Have heard of the term but dont know its meaning Know what the term means  
a. Potable water 1 2 3  
b. Wastewater 1 2 3  
c. Greywater 1 2 3  
d. Sewage 1 2 3  
e. Recycled water 1 2 3  
f. Effluent 1 2 3  
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Measuring sustainability ethic
Q-6 How important are each of the following when choosing an approach to meeting the new water quality regulations in the Willamette River? If you have no opinion of one, please leave it blank. How important are each of the following when choosing an approach to meeting the new water quality regulations in the Willamette River? If you have no opinion of one, please leave it blank. How important are each of the following when choosing an approach to meeting the new water quality regulations in the Willamette River? If you have no opinion of one, please leave it blank. How important are each of the following when choosing an approach to meeting the new water quality regulations in the Willamette River? If you have no opinion of one, please leave it blank. How important are each of the following when choosing an approach to meeting the new water quality regulations in the Willamette River? If you have no opinion of one, please leave it blank. How important are each of the following when choosing an approach to meeting the new water quality regulations in the Willamette River? If you have no opinion of one, please leave it blank.
Not Important at All Limited Importance Somewhat Important Important Very Important

a. Prevent pollution 1 2 3 4 5
b. Protect human health 1 2 3 4 5
c. Be a long term solution 1 2 3 4 5
d. Be energy efficient 1 2 3 4 5
e. Be financially sound 1 2 3 4 5
f. Protect fish and wildlife 1 2 3 4 5
g. Have low greenhouse gas emissions 1 2 3 4 5

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Acceptance of recycled water uses
Q-7 Q-7 How much do you favor the use of recycled wastewater for each of the following? If you dont know or have no opinion of a use, please leave it blank. How much do you favor the use of recycled wastewater for each of the following? If you dont know or have no opinion of a use, please leave it blank. How much do you favor the use of recycled wastewater for each of the following? If you dont know or have no opinion of a use, please leave it blank. How much do you favor the use of recycled wastewater for each of the following? If you dont know or have no opinion of a use, please leave it blank. How much do you favor the use of recycled wastewater for each of the following? If you dont know or have no opinion of a use, please leave it blank. How much do you favor the use of recycled wastewater for each of the following? If you dont know or have no opinion of a use, please leave it blank. How much do you favor the use of recycled wastewater for each of the following? If you dont know or have no opinion of a use, please leave it blank.
Highly Unfavorable Unfavorable Unfavorable Neutral Favorable Highly Favorable
a. Irrigate golf courses Irrigate golf courses 1 2 3 3 4 5
b. Irrigate landscaping in business parks Irrigate landscaping in business parks 1 2 3 3 4 5
c. Irrigate public parks Irrigate public parks 1 2 3 3 4 5
d. Irrigate school grounds Irrigate school grounds 1 2 3 3 4 5
e. Irrigate non-edible agricultural crops (grass) Irrigate non-edible agricultural crops (grass) 1 2 3 3 4 5
f. Irrigate agricultural crops for human consumption Irrigate agricultural crops for human consumption 1 2 3 3 4 5
g. Use in industrial processes Use in industrial processes 1 2 3 3 4 5
h. Use to cool buildings Use to cool buildings 1 2 3 3 4 5
i. Flush toilets in public buildings Flush toilets in public buildings 1 2 3 3 4 5
j. Supply fire hydrants in the city Supply fire hydrants in the city 1 2 3 3 4 5
k. Supply car wash businesses Supply car wash businesses 1 2 3 3 4 5
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Percentage of respondents choosing "very
favorable" or "favorable" for various recycled
water uses.
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Grouping uses of recycled water

• Factor analysis looks for patterns in responses
• 3 groups of recycled water uses
• High contact (irrigate schools, public parks,
  edible crops)
• Low contact (irrigate business parks, golf
  courses, non-edible crops, use in industrial
  processes)
• Other uses (building cooling, toilet flushing,
  fire hydrants, car washes)
• Factor scores were used in 3 regressions, one for
  each group

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Regression coefficients for factors of water
reuse acceptance
Independent Variable High Contact Low Contact Other Uses
Informed -0.018 (0.794) -0.088 (0.184) -0.093 (0.157)
Knowledge of wastewater 0.004 (0.909) 0.100 (0.009) 0.059 (0.120)
Aware of problem (1yes) -0.394 (0.000) -0.019 (0.862) -0.043 (0.694)
Sustainability index 0.026 (0.051) 0.022 (0.101) 0.040 (0.003)
Trust to serve public interest 0.111 (0.109) 0.125 (0.067) 0.080 (0.237)
Gender (1male) 0.279 (0.004) -0.208 (0.029) 0.068 (0.474)
Age -0.003 (0.324) -0.003 (0.306) -0.003 (0.355)
Education -0.020 (0.627) 0.029 (0.485) 0.090 (0.028)
Children present (1no) -0.045 (0.663) -0.165 (0.104) 0.172 (0.088)
P-values for the coefficients are in parenthesis.
Red values are significant at 95 denote
significance at 90.
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Policy implications

• City should pursue water reuse there is high
  acceptance of most uses
• Low contact uses are most accepted
• Make sure a program adheres to the principles of
  sustainability
• Educate public about wastewater treatment, water
  reuse, technologies, and reason for water reuse
• If high contact uses are chosen, make a special
  effort to include women

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Study limitations

• Results should be considered hypothetical
• Studies show that factors influencing acceptance
  change when specific plans are presented
• Little information about water reuse was
  presented due to space
• Many respondents stated they wanted more
  information

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Questions?
Support provided by Institute for Water and
Watersheds
Master of Public Policy Program