Intro Page - SAHRA - Sustainability of semi-Arid Hydrology and …cierzo.sahra.arizona.edu/research/TA5/loggers_web.pdf · SAHRA Sustainability of semiArid Hydrology and Riparian

Sustainability of semiArid Hydrology and Riparian AreasSAHRA

Intro Page

GAINING INSIGHTS ON DOMESTIC WATER DEMAND THROUGH REMOTE SENSING

Applications of Low-cost Loggers

Gary Woodard, Ass’t. Director, SAHRA

Center for Sustainability of semi-Arid Hydrology & Riparian Areas

Research funded in part by:Bureau of Reclamation

Phoenix Area Office


Factors Affecting Residential Water Demand

Housing Type• Duplex/triplex• Mobile home• Single family detached• Townhouse/condo• Apartment

Residency• Age of home• Years lived in home• Years lived in community

Monetary Factors• Own or rent home?• Value of home/monthly rent• Annual income• Pay the water bill?

Demographics• Children under 5• Children 5 to 18• People home during day• Head of household retired?

Appliances• Clothes washer• Dishwasher• Garbage disposal• Evaporative cooler/AC• Installed low-flow device?

Landscape Factors• Amount of turf• How landscape is irrigated• Swimming pool


Effects of selected water demand factors*

154.486.168.319.6Swimming Pool

0.034/ft20.034/ft2n/a3.9Turf w/o regular irrigation

0.038/ft20.038/ft2n/a22.3Turf w/hose & sprinkler

0.043/ft20.043/ft2n/a11.5Turf w/in-ground sprinkler

-19.8n/a-19.847.5Installed Low-flow Device

26.626.6n/a63.5Evaporative Cooler

11.5n/a11.549.1Garbage Disposal

11.0n/a11.057.1Dishwasher

21.9n/a21.991.3Clothes Washer

Total Peak Demand

Peak Outdoor

Indoor Demand

% Homes with FactorFactor of Water Demand

*Values in gallons/day/household in Tucson, AZ. Source: Woodard & Rasmussen.


Impact of precipitation on water demand

Paradise Valley Water Demand


Rain suppresses water demand for several days

Effect of Rain on Phoenix Water Demand

-25

-20

-15

-10

-5

0t-2 t-1 t0 t1 t2 t3

Days since rain event

Dec

reas

e in

dem

and

(gpc

d)

WinterSpring/Fall

Summer


Ideal residential water demand data

Breakthroughs in forecasting water demand and evaluating conservation programs require data that:

• are disaggregated below the household level to the water use;

• have a time resolution finer than monthly meter readings; and

• are collected for longer periods of time.

Efforts to date based on micro-metering and self-reported usage logging suffer from:

• Hawthorne effect

• self-selection bias

• small sample sizes


Wet and dry sides of a water meter

Source: www.water-meters.com

Spinning turbine on the wet side of the water meter is coupled with the gears on the dry side by a pair of bar magnets.

Magnetic pulses from a water meter can be detected via: inductance loop (generator); reed switch (bicycle speedometers); or Hall effect sensor (proximity sensors).


Conventional data logger for sensing water demand

Logger records number of meter magnet turns every 5 seconds.

Logger can be left in meter box for up to 2 weeks.


Remote Sensing of Domestic Water Demand

A residential customer in Tucson, Arizona.


Problems found with aging ULF toilets

0

5

10

15

20

25

30

35

40

45

Double Flush FlapperLeak

High FlushVolume

SomeProblem

13.515.3

26.4

42.9

Percent of Households Experiencing Problem


Flapper valve selection

Flapper valves and other toilet flush mechanisms come in a bewildering array of types, styles, materials and colors.

Finding one for a particular ULF toilet can be nearly impossible.


Do low-flow shower heads mean longer showers?

Shower Duration as a Function of Flow Rate


Making place-based research results more transferable

Ideally, we would disaggregate domestic water demand using large numbers of semi-permanent sensor/logger installations.

Large numbers of sensor/loggers would capture the effects of:

• demographics• housing types• landscape types

Semi-permanent sensor/logger installations would capture impacts of:

• price changes• seasonal weather and climate fluctuations• maturation of landscaping


Cost issue with data loggers and PDA alternative

$2,000 - $2,500 each256K memoryLimited resolution, capacity

$100 - $150 each8 - 128 mbyte memoryHigh resolution, capacity


Alternative to temporary use of sensors

• Costs < $100

High-accuracy meter with integrated Reed switch

• Records to 0.01 gal.and logs to 0.1 gal.

• Designed forpermanent installation


Disaggregating domestic demand inexpensively


Example of conservation fixtures and landscaping

Conservation Measures:

• turf removed

• Xeriscape

• drip irrigation

• irrig. timer

• ULF toilets

• low-flow shower heads


Water meter traces reveal domestic demand details

Gross features of water demand are apparent at this 3-day resolution.



Details of water demand are apparent at this 6-hour resolution.



Fine details of water demand are apparent at this 1-hour resolution.


Current uses of the technology

Data loggers coupled to water meters via reed switches are being used to investigate water demand characteristics and conservation potential of:

• “ranchettes” with domestic wells and septic systemsnear Sonoita, Arizona (support from Audobon Society)

• homes with wells near the Upper San Pedro River insoutheastern Arizona (support from Cochise County)


Proposed uses of the technology

Data loggers with Hall Effect sensors could be used for short-term logging of existing meters

Data loggers with associated cell phone or pager hardware could be used to intelligently control residential irrigation systems


Test manifold construction

A computer-controlled test manifold was constructed to test logger hardware and software and for educational purposes.


Test manifold for logger software & hardware

Test manifold contains several plumbing fixtures, including:

• low-flow shower• high-flow shower• swamp cooler line• toilet tank valve• drippy faucet• irrigation valve• washing machine

fill line


Manifold simulates residential water uses


Use of solar cells indefinitely extends deployment

Batteries cannot power logger more than a few weeks, but inexpensive, weather-proof solar cells can provide several months of data logging.


Solar cell recharging gel battery


Twin solar cells provides indefinite field life

Documents

Intro Page - SAHRA - Sustainability of semi-Arid Hydrology and …cierzo.sahra.arizona.edu/research/TA5/loggers_web.pdf · SAHRA Sustainability of semiArid Hydrology and Riparian