1 / 32

Spokane County Residential Water Use Survey Results

Mike Hermanson Water Resources Specialist Spokane County Utilities. Spokane County Residential Water Use Survey Results. Overview. Background & Purpose Survey Development Survey Distribution Survey Response Results. Purpose.

wang-mcdonald
Download Presentation

Spokane County Residential Water Use Survey Results

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mike Hermanson Water Resources Specialist Spokane County Utilities Spokane County Residential Water Use Survey Results

  2. Overview • Background & Purpose • Survey Development • Survey Distribution • Survey Response • Results

  3. Purpose • Refine estimate of self supplied residential water use for Spokane County Water Demand Forecast Model • Other water use estimates utilize public water system data of similar areas. Is this assumption valid?

  4. Background • USGS & the State of New Hampshire conducted a study to test the “public supply is similar to self supply” assumption. • The study concluded that the assumption is valid, but it did not incorporate outdoor water use, and important component in Spokane County.

  5. Survey Development • 4 page survey based on USGS & AWWA surveys. Local input provided by water purveyors, Ecology, Conservation District, local government. • Survey included: • Household information • # of people, home size, parcel size • location • water source • Indoor use • # of fixtures, • # of low flow toilets, shower heads • Outdoor use • size of irrigated landscape • type of irrigation system • # of days/week, time per station, time of day • Other uses – livestock, gardens, pools,

  6. Survey Distribution • Classroom – Water on Wheels • 204 classrooms/4,763 students • 799 responses • Post card to households outside water district boundaries • 15,000 postcards • 450 responses

  7. Survey Response Locations

  8. Survey Response • Was the survey representative? • In 2008 there were approximately 150,000 single family housing units • A representative sample with a 99% confidence interval and a 3.75% error rate is 1,174 samples collected randomly. • The surveys were not collected randomly – How does the demographic data correspond to County averages?

  9. Survey Response • Distribution method favored homes with children. • Bias towards larger, newer homes • All county average is impacted by City of Spokane residences

  10. Survey Results • Focused on differences in amount of irrigated landscape: • Comparisons between groups distinguished by a particular variable • Average amount of irrigated landscape of public supply vs. self supply

  11. Survey Analysis • Independent two sample t-test for samples of unequal size and unequal variance 7,646 ft2 8,358 ft2 Average area of irrigated landscape Public supply = 8,358 ft2 Self supply = 7,646 ft2 Insignificant Difference between groups 7,646 ft2 8,358 ft2 Significant Difference between groups

  12. Public vs. Self Supplied Table 6 –1: Public vs. Self Supplied - Average Irrigated Landscape

  13. Public vs. Self Supplied

  14. Public vs. Self Supplied

  15. Public vs. Self Supplied

  16. Public vs. Self Supplied

  17. Public vs. Self Supplied Table 6-2: Watering Time Per Week-Public vs Self Supplied

  18. Influences on Self Supplied Water Use – Well Yield Table 6 - 3: Well Yield and Average Area of Irrigated Landscape Table 6 -4: Well Yield Grouping Significance Testing

  19. Influences on Self Supplied Water Use – Residence Setting Table 6 -5: Residence Setting and Average Area of Irrigated Landscape Table 6 –6: Residence Setting Significance Testing

  20. Influences on Self Supplied Water Use – Lot Size Table 6 -6: Lot Size and Average Area of Irrigated Landscape

  21. Influences on Self Supplied Water Use – Home Size Table 6 - 7: Home Size and Average Area of Irrigated Landscape Table 6 - 8: Home Size Significance Testing

  22. Influences on Public Supplied Water Use – Residence Setting Table 6 - 9: Residence Setting and Average Area of Irrigated Landscape Table 6 - 10: Residence Setting Significance Testing

  23. Influences on Public Supplied Water Use – Lot Size Table 6 - 11: Lot Size and Average Area of Irrigated Landscape

  24. Influences on Public Supplied Water Use – Lot Size Table 6 - 12: Lot Size Significance Testing

  25. Influences on Public Supplied Water Use – Home Size Table 6 - 13: Home Size and Average Area of Irrigated Landscape Table 6 - 14: Home Size Significance Testing

  26. Water Use Influences Summary • Self Supplied • well yield, residence setting, & home size impact landscape irrigation. • lot size does not impact landscape irrigation • Public Supplied • residence setting, home size and lot size impact landscape irrigation

  27. Comparison of other outdoor water use Table 6 - 15: Comparison of other outdoor water use

  28. Comparison of Indoor Water Use Table 6 - 17: Comparison of Indoor Fixtures & Appliances

  29. Source Problems/Limitations Table 6 - 18: Number of Water Quality or Quantity Issues Identified

  30. Water Quality/Quantity Problems

  31. Hauled Water

  32. Source Limits Water Use

More Related