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The best solution often lies in the unapparent.
John Olaf Nelson
[email protected]
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Eliminate Water Supply
Impact
of New Residential
Development
withZero FootprintLeague of California Cities
ConferenceSept. 26, 2008
John Olaf Nelson Water Resources Mgt
[email protected]
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What is Zero Footprint?
A. Onsite Reduction of Potable Demand:
Conservation Measures
Recycled Water Use
B. Off-site Offsets of Potable Demand:
Utility Conservation Programs
Utility Recycled Water Projects
A + B = Zero Net Potable Demand
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How Paid For?
Onsite Reductions are cost to
Developer at time of construction.
Off-site Offsets are payments made to
Utility (lump sum or an added
connection fee.
Both reduce profit margin to Developer.
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How are Savings Assured?Onsite
Use of approved devices
Inspection by Utility
Conditions, Covenants & Restrictions
(CC&Rs)
Off-site Factor of Safety in estimating savings
Utility sets/approves Offset Fee
Utility administers off-site cons. programs
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EPAct Standards
ULFTs 1.6 gpf
Shower heads 2.5 gpm
Faucets/aerators 2.2 gpm
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New Standards - Inside
HE Toilets 1.28 gpf*
HE Shower heads 2.0 gpm
HE Faucets/aerators 1.5gpm**
HE Clothes washers 5.5
gcd HE Dishwashers 0.6 gcd
Submeter MF 21.8 gpd
Structured Plumb./HWD 8.5 gpd
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HE Toilets and Appliances
Dual Flush
Clothes Washer & Dryer
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Structured Plumbing
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in Plan View
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HWD RetrofitHot Cold
Receiver
< Recycle Pump and
Temperature Sensor
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New Standards - Outside
Limit Turf for SF to < 800 sf
No narrow strips of turf (< 8 ft)
Xeriscape plant materials
Smart (ET) Controller
Meet States MAWA requirement *
* 70% ET Adjustment Factor
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XeriscapeTraditional
Xeriscape
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ET Controller
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B/C of Some Onsite Measures
HE Clothes Washer
4.4
Submetering MF 2.3 HE Dishwasher 1.3
Structured Plumbing 1.2
ET Controllers for SF 0.7
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Added Unit Cost
HE Clothes Washer $238
Submetering MF $273
HE Dishwasher $111 Structured Plumbing $573
ET Controllers for SF $312
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Select Off-site Programs & B/C
Utility Cust.
ET Contr. - Irr. (100%) 2.6 5.1
Submetering MF (100%) 1.9 2.3
ET Contr. - UQ SF (75%) 1.2
1.5
HWD Retrofit (40%) 1.0 1.8
ET Contr. - Typ. SF (50%) 0.6 0.5
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Estd Program Unit Cost to Utility
ET Contr. - Irr. (100%) $1,180
Submetering MF (100%) $473
ET Contr. - UQ SF (75%)
$590
HWD Retrofit (40%) $270
ET Contr. - Typ. SF (50%) $324
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Case Example
Location:
Inland Coastal Valley of North CA
33 inches of annual rainfall (nil in summer)
Description:
300 acres (29% open space)
1,736 DUs (SF = 68%) 250,000 sf of commercial
Total Project Demand = 580 afa (0.518 mgd)
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EDU Relationships
EDU Ratio
SF Detached 1.00
SF Attached 0.70 MF 0.53
Second Units 0.24
Note: 1,736 DUs = 1,330 EDUs
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Onsite Reductions and
Remaining Offset NeedOnsite Reductions:
Conservation 23%
Recycled Water Use 24%
Total 47%
Remainder to offset viaOff-site Programs: 53%
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Measures and Distribution
of Onsite Reductions
`
Recycle 51% EPAct 25%
HE Clothes Washers 9%
Submetering 4%
Commercial and HE Dishwasher 1% eachStructured Plumbing w. HWD
4%
ET Controllers 5%
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Expand Existing 28%
ET - Upper Quart. SF 16%
Increase Clothes
Washer Rebates 6%
HWD Retrofit 8%
Submetering MF
15%
ET - Irr. Only 18%
ET - Typical SF 9%
Note: ET Controller Programs total 43%
Off-site Program Savings and
Distribution
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Case Example Recap
M$ $/DU $/EDU
Onsite Conservation 1.2 684 892
Onsite Recycled 3.2 1,857 2,424Off-site Conservation 2.9* 1,650
2,154**
Total $7.3 $4,191 $5,470
* Includes 22% Safety Factor for est. errors.
** Offset Fee to pay for Off-site Programs
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Build-it-Green Points
Points
Build-It-Green points for SF: 294
Portion in Water category*: 66
Application of New Standards
can capture: 46
* Excluding consideration of Recycled Water Use
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John Olaf Nelson Water Resources Mgt
[email protected]
