Water and Land UseExecutive Water Finance Board
The importance of objective data
• “Most of the world will make decisions by either guessing or using their gut. They will be either lucky or wrong.”- SuhailDoshi, CEO, Mixpanel
• “It is a capital mistake to theorize before one has data.”- Arthur Conan Doyle, Author of Sherlock Holmes
Different Perspectives
Image source: https://balajiviswanathan.quora.com/Lessons-from-the-Blind-men-and-the-elephant
Source: Ariely, Dan. Lecture at Duke University, Spring 2013
Different Perspectives
Different Perspectives
Source: Adelson, Edward H., Vision Science, MIT 1995
How much water did it take to make this cup of Coffee?
8 oz?
200 Liters?
Source: Tompkin, Jonathan. Lecture at University of
Illinois at Urbana Champagne, Fall 2012
Embedded Water
• In a cup of coffee• 250 ml (8 oz.) of water in the cup
• Including irrigation - 200 liters! (Over 50 gallons)
• Consumers are using over 200 liters of water for a cup of coffee
• Embedded water in common products• 1 Kg of wheat = 1300 liters
• 1 kg Rice = 3500 liters
• 1 kg of hamburger = 15,000 liters
• 1 kg of Microchips = 15,000 liters
• 1 kg of cotton shirts = 4,000 liters
• Car manufacturing = 500,000 liters of water
Source: Tompkin, Jonathan. Lecture at University of Illinois at Urbana Champagne, Fall 2012
How much water did it take to make this cup of Tea?
20 Liters
Source: Tompkin, Jonathan. Lecture at University of Illinois at
Urbana Champagne, Fall 2012
Land Use and Water
• Land use impacts water use…period.
• Land use does not equal water use
• “How we grow matters”
County development – Lot Sizes
• Used County Assessor data to determine average lot size by year in several counties
• Selected only “residential” lots with a “year built”
Salt Lake County
Source: Utah's State Geographic Information Database – Salt Lake County Parcels LIR layer: Spring 2018
Salt Lake County
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 More
1996 Percent
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 More
2016 Percent
Bins Frequency
2016
Percent
0.1 333 25%
0.2 521 39%
0.3 272 20%
0.4 85 6%
0.5 44 3%
0.6 25 2%
0.7 11 1%
0.8 7 1%
0.9 6 0%
1 15 1%
More 25 2%
Bins Frequency
1996
Percent
0.1 772 12%
0.2 1763 26%
0.3 2438 37%
0.4 855 13%
0.5 309 5%
0.6 131 2%
0.7 41 1%
0.8 21 0%
0.9 20 0%
1 90 1%
More 216 3%
Lot size in acres Lot size in acres
.22 average lot.33 average lot
Source: Utah's State Geographic Information Database – Salt Lake County Parcels LIR layer: Spring 2018
Utah County
Source: Utah's State Geographic Information Database - Utah County Parcels LIR layer: Spring 2018
Utah County
0%
5%
10%
15%
20%
25%
30%
35%
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 More
1996 Percent
0%
5%
10%
15%
20%
25%
30%
35%
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 More
2016 Percent
Bins Frequency
1996
Percent
0.1 716 21%
0.2 707 21%
0.3 1018 30%
0.4 327 10%
0.5 219 6%
0.6 90 3%
0.7 40 1%
0.8 20 1%
0.9 23 1%
1 52 2%
More 169 5%
Bins Frequency
2016
Percent
0.1 1266 31%
0.2 898 22%
0.3 989 24%
0.4 341 8%
0.5 159 4%
0.6 155 4%
0.7 45 1%
0.8 31 1%
0.9 16 0%
1 38 1%
More 119 3%
.33 average lot.56 average lot
Lot size in acres Lot size in acres
Source: Utah's State Geographic Information Database - Utah County Parcels LIR layer: Spring 2018
Davis County
Source: Utah's State Geographic Information Database Davis County Parcels LIR layer: Spring 2018
Davis County
Bins Frequency
1996
Percent
0.1 207 10%
0.2 495 25%
0.3 832 42%
0.4 188 9%
0.5 93 5%
0.6 49 2%
0.7 23 1%
0.8 9 0%
0.9 12 1%
1 25 1%
More 61 3%
Bins Frequency
2016
Percent
0.1 240 18%
0.2 294 22%
0.3 440 32%
0.4 189 14%
0.5 102 8%
0.6 36 3%
0.7 11 1%
0.8 11 1%
0.9 5 0%
1 0 0%
More 28 2%
.27 average lot.29 average lot
Source: Utah's State Geographic Information Database - Davis County Parcels LIR layer: Spring 2018
Washington County
Source: Utah's State Geographic Information Database - Washington County Parcels LIR layer: Spring 2018
Washington County
Lot size in acres Lot size in acres
.38 average lot .36 average lot
Source: Utah's State Geographic Information Database - Washington County Parcels LIR layer: Spring 2018
Bins Frequency
1996
Percent
0.1 581 35%
0.2 343 20%
0.3 366 22%
0.4 101 6%
0.5 53 3%
0.6 25 1%
0.7 15 1%
0.9 30 2%
1 24 1%
More 146 9%
Bins Frequency
2016
Percent
0.1 283 16%
0.2 396 23%
0.3 691 39%
0.4 146 8%
0.5 67 4%
0.6 44 3%
0.7 16 1%
0.9 22 1%
1 19 1%
More 75 4%
Is this our smaller lot future?
https://www.newfrontiertinyhomes.com/tiny-house/cornelia/ http://planning.unc.edu
Smaller lots…larger homes…less lawn
Source: Utah's State Geographic Information Database - Utah County Parcels LIR layer: Spring 2018
Smaller lots…larger homes…less lawn
Source: Utah's State Geographic Information Database - Utah County Parcels LIR layer: Spring 2018
Smaller lots…larger homes…less lawn
Smaller lots…larger homes…less lawn
Source: Utah's State Geographic Information Database - Washington County Parcels LIR layer: Spring 2018
Are smaller lots more efficient?
• It depends…
• Multi-family and rental units less sensitive to:• price changes
• weather
• long-term trends/billing history
• Single family units may use less per capita
• Water is decoupling from density
• Landscaping is more important than lot size
Color Infrared Imagery
https://www.geomart.com/products/aerial/cir.htm
http://cstars.metro.ucdavis.edu/files/3613/4
419/0702/Lecture_3-Leaves__Plants.pdf
http://www.mngeo.state.mn.us/chouse/airphoto/cir.html
Remote Sensing
Salt Lake County Example
~.25 acre lots
Salt Lake County Example
~.25 acre lots
Salt Lake County Example
~55% Vegetation Cover
Desert oasis?
Photo Credit: VisitStGeorge.com
Recent Washington County Large Lots
~.5 acre lots
Recent Washington County Large Lots
~.5 acre lots
Recent Washington County Large Lots
~28% Vegetation Cover
Recent Washington County Large Lots
>.5 acre lots
Recent Washington County Large Lots
>.5 acre lots
Recent Washington County Large Lots
~1.5% Vegetation Cover
A small lot example…
These lots average just .1 acre
A small lot example…
These lots average just .1 acre
A small lot example…
Vegetation coverage ~ 30%
A small lot example
Ivins
~22%
~16%
<2%
Macro Analysis
• Analyzed subset of Washington County.
Macro Analysis
• Analyzed subset of Washington County.
• Only developed areas
Macro Analysis
• Analyzed subset of Washington County.
• Only developed areas
• >5,000 acres of vegetation
• ~17% of developed area
Percent Vegetative Cover
St. George – Vegetation vs Water Use
Salt Lake County Example
• ~44% vegetation cover
• 3% golf courseVegetation
Washington County Water-Related Land Use
Irrigated
Not Irrigated
Riparian
Sub-Irrigated
Urban
Water
Source: Utah's State Geographic Information Database – Water Related Land Use layer: Spring 2018
- ~12,000 acres
The Future
• Washington County is growing
• What will growth look like?• More than double the population by 2065
Washington County Growth
1991~48,000 people~15,000 acres~3.3 PPDA
Washington County Growth
2017~165,000 people
~60,000 acres~2.7 PPDA
Washington County Growth
2065?~508,000 people~122,000 acres
~4.2 PPDA
*Note: potential growth scenario for illustration only – not based on actual development plans
Washington County Growth
Washington County 2045 - 2065
• More than twice the population
• Twice the land developed?
• How much new irrigated vegetation? • ~ 10,000 new acres of vegetation at current rates.
• ~ 30,000 acre feet of water per year for new irrigation needs*
• *At least some ag water likely to convert to M&I
33%
25% less use per person; new supply from projects, little
from farms; max 30% grass in yards/parks
24%
15% less use per person; new supply from projects and
farms; max 50% grass in
yards/parks
20%
40% less use per person; new supply from local projects and farms; almost
no grass in yards/parks
13%
Same use per person as
today; new supply from projects and
farms
12%
25% less use per person; new supply from projects and
farms; max 30% grass in
yards/parks
S U R V E Y R E S U L T S :
SC EN AR IO C H OIC ES( W AT E R - S TAT E )
35%
25% less use per person; new supply from projects, little
from farms; max 30% grass in yards/parks
26%
15% less use per person; new supply from projects and
farms; max 50% grass in
yards/parks
29%
40% less use per person; new supply from local projects and farms; almost
no grass in yards/parks
5%
Same use per person as
today; new supply from projects and
farms
5%
25% less use per person; new supply from projects and
farms; max 30% grass in
yards/parks
S U R V E Y R E S U L T S :
SC EN AR IO C H OIC ES( W AT E R – W A S H I N G T O N C O U N T Y )
+2% +9% +2% -8% -7%
Difference from state
Localscapes…
https://localscapes.com/
Water Strategy Land Use Recommendations
• Water-efficient by design
• Integrate water planning and land use planning to achieve long-term water use efficiencies in urban areas.
• Include water conservation and water source protection elements in city and county general plans
• Enact zoning ordinances that allow the housing market to move to higher densities
• Enact landscaping and other ordinances
• Utilize dual water source delivery systems where feasible
Source: Utah's Recommended State Water Strategy
Key Points
• We need good data
• Lot sizes decreasing, home sizes increasing
• Washington County (and all of Utah) has room to GROW
• HOW we grow matters
• Social “norms” can be powerful conservation tools
The End…