By Mackenzie Boyer
Want to know how much potential a water utility customer has
to conserve irrigation? First you need to know how much water they’re using. What
about figuring this out for every customer in a utility? You’ll want to check
out our recently published article “Mining for Water: Using Billing Data to Characterize Residential Irrigation Demand.”
Treasure Trove
A utility’s monthly water billing records can hold a wealth
of information - a gold mine, we would say. The monthly records, even when
water meters measure only indoor and irrigation water combined, can provide a
great insight into irrigation behavior of individual customers. And if the
utility also has parcel identification data linked to their billing records?
Jackpot.
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| Research area |
Tampa Bay Water just happened to have some very
detailed, very comprehensive billing data for their six member governments
(Pasco County, New Port Richey, Pinellas County, St. Petersburg, Hillsborough
County, and Tampa). Our analysis of their data used over 30 million monthly
billing records of over 165,000 customers - comprehensive, to say the least. The
monthly total water use (indoor and outdoor combined) and parcel data were used
to estimate each customer’s monthly irrigation demand (what we estimate
customers actually used for irrigation). Each customer’s monthly gross
irrigation required (GIR, what we estimate a landscape actually needed to be
well-watered) was estimated using parcel, weather, and soil data.
Managing and manipulating the data required some heavy
computing power. The statistical programs SAS and R were used, with R
selected specifically to run a series of 875,000 calculations at UF’s High Capacity Computing Center. (It still took the computing center over a
week to run all the equations.) ArcGIS was used to map customer locations
and determine their site-specific weather and soil conditions. We grouped
customers by their irrigation habits by comparing their demand to GIR (how much
they irrigated compared to how much their landscape needed). Our groups were:
high, medium, low and occasional irrigators.
Stay the Course
We found that many, many customers in the Tampa Bay region
do not regularly irrigate (our occasional irrigator group). For this 85% of customers,
the old adage “If it isn’t broken, don’t fix it” holds true. These customers
should not be actively recruited for conservation programs because we don’t
want to inadvertently increase their irrigation by recommending irrigation
practices that use more water than their current practices.
Each occasional irrigator did not irrigate much, but the
group was so large that the occasional irrigators were responsible for 51% of
irrigation utility-wide. In contrast, only 2% of customers were classified as
high users, and these customers were responsible for 9% of the irrigation
demand.
Keys to Success
Successful irrigation conservation programs are far from one
size fits all. Conservation programs should be targeted to the high user customers
to maximize the water savings potential. Utilities often have the tools in
their historical monthly billing records (even without the comprehensive data
of Tampa Bay Water) to estimate how much irrigation customers use. Using this
knowledge, they can direct conservation efforts to those who could benefit the
most.
