In order to develop accurate profiles of California end-user water demand, this study obtained
data on hourly water use for commercial, industrial, and public buildings and agricultural sites as
well as single- and multi-family residences. The authors performed flow trace analysis to
examine where, when, and how much cold water was used in six end-use categories plus urban
irrigation. The authors developed disaggregated hourly water demand profiles (indoor,
continuous, and outdoor) for public buildings, schools, and hospitals. For industrial sites, water
use was separated into continuous, process, and irrigation. If any of the 69 public buildings in the
study showed evidence of irrigation, the seasonal variation in water use was estimated based on
combined historical billing data and logged data. Flow trace data (26 traces) were collected from
12 industrial facilities. Six other flow trace files from previous studies for 5 industrial sites also
were used to create hourly water demand profiles.
1.2.6 East Cherry Creek Valley Water and Sanitation District: Irrigation Demand
By Aquacraft, Inc., Water Engineering and Management, Boulder, CO.
The East Cherry Creek Water District, near Aurora, CO, conducted a study to estimate how
much land could be irrigated given the water rights, storage, and pumping capacity of a planned
raw water distribution system. Based on a typical annual per-lot irrigation requirement of 2.5
feet, 1,000 acre-feet of water would supply a maximum of about 400 acres of land. The authors
used micro-flow metering to measure peak demand in 29 irrigation systems that the raw water
system might serve.
The study used the flow data to build a database of one-minute, hourly, and daily
demands on the system and to examine the relationships among irrigated area and peak
instantaneous, hourly, and daily demands. Without changing system scheduling, 260 acres was
the maximum area that could be served under the observed demand patterns. Increasing
scheduling efficiency would increase the reliability of the system and the area it could serve. If
the largest schools and parks avoided irrigating on successive days and alternated their water use,
the observed demands would allow for serving a maximum of 342 acres. The situation could be
improved further by a radio-controlled system that could track ET and curtail individual systems
as needed during peak periods.
1.2.7 1999 Residential End Uses of Water Study (REUWS)
By Aquacraft, Inc. (which is updating the REUWS in 2011–2013).
352 pages, including appendixes.
(among many websites)
The REUWS study aimed to obtain data on the end uses of water in residential settings across
North America. The authors derived outdoor use from each site’s historical billing data by
calculating the average daily indoor consumption from REUWS data-logging results,
extrapolating that consumption throughout a year, and subtracting that amount from the
historical consumption. The authors performed a regression analysis using net ET and the
average annual outdoor use obtained using a leveraged approach. The least-squares fit of a
straight line to the data yielded a coefficient of determination of 0.59, an improvement over data
based on average winter consumption (a common approach). The authors found a strong
relationship between climate and average outdoor water use, as well as a strong positive
relationship with home square footage (a parameter that might serve as a proxy for standard of
living and thus a greater ability to pay for more discretionary water use).
1.2.8 Urban Water Use in California
By California Department of Water Resources (DWR).
For this bulletin, the DWR analyzed water data for 1980–87 for 68 cities throughout California.
Seasonal use was derived by the minimum-month method of analyzing water use records. The
“Seasonal Versus Outdoor Use” section notes that in Southern California, 90% of seasonal
outdoor water use in the residential sector and 84% in the non-residential sector were attributable
to irrigation. The DWR found that baseline water use for both Los Angeles and Fresno were
roughly the same, but that Fresno’s seasonal use was greater because of the large landscape
irrigation requirement during summer in the Central Valley.
1.2.9 Residential Irrigation Uniformity and Efficiency in Florida
By M.C Baum, M.D. Dukes, and G.L. Miller.
American Society of Agricultural and Biological Engineers (ASABE).
Paper number FL03-100, 2003 Special Meeting Papers . St. Joseph, Mich.
This study aimed to document irrigation water use in the Central Florida Ridge region. Using
data collected from weather stations, the authors calculated reference ET to determine required
irrigation amounts for each site. The study found that over-irrigation often was a result of trying
to maintain “acceptable turf quality,” socioeconomic level, or a misunderstanding of irrigation
run times based on equipment type and seasonal ET rates. Irrigation accounted for more than
70% of the volume of residential water use for the houses in this study.
1.3 Water Needs of Individual Landscapes
The resources described in this section provide tools and evaluate methods for calculating the
needs of individual landscapes in specific locations.
1.3.1 Home Water Works website
This website provides a water calculator that estimates residential water use based on user
responses to questions. The water calculator utilizes per-capita demand curves developed by
Aquacraft from various residential end-use studies. Outdoor use is estimated based on local
climate zone, irrigated area, landscape type, and irrigation method.
1.3.2 Revised Draft Water-Efficient Single-Family New Home Specification:
Water Budget Tool, Version 1.01
By EPA WaterSense.
This tool helps determine whether a landscape design meets Option 1 of the EPA’s WaterSense
Water Budget Approach to meeting the New Home Specification. The user calculates the
landscape water allowance (LWA) for a residential landscape based on peak watering month and
the landscape water requirement (LWR). The goal is for the LWR to be no more than the LWA.
1.3.3 Residential Benchmarks for Minimal Landscape Water Use
By C.C. Romero and M.D. Dukes, Engineering Dept., Univ. of Florida (UF).
Prepared for UF Water Institute in partial fulfillment of the Conserve Florida
Water Clearinghouse Research Agenda, DEP Contract No. WM955–
amendment 3. 49 pages.
Much research has been conducted on the irrigation requirements of turfgrass and agricultural
crops, but little on landscape plants. This paper reviews ways to estimate plant water use, usually
using an equation for soil-water balance. The results can be used to quantify the theoretical
irrigation requirements of turfgrass and landscape plants. Given the theoretical requirements, one
can establish benchmarks for water use and assess potential water savings. After reviewing the
benchmarking literature, the authors concluded that more research is needed to estimate the
water needs of ornamental plants in order to evaluate potential water savings. This summary
paper also reviews methods of estimating ET using crop coefficients (Kc) and landscape
coefficients (KL). The landscape coefficient, created to determine irrigation scheduling for
landscapes, is calculated as the ratio of actual evapotranspiration (ETa from turfgrass plus
ornamentals) to ETo. KL includes stress, density, microclimate, and vegetation coefficients
(coefficients for species, density, and microclimate). A computer program for calculating
landscape coefficient, the Landscape Irrigation Management Program (LIMP), was developed by
Snyder and Eching in 2005. LIMP provides a quantitative approach to estimating
landscape irrigation needs. LIMP calculates the regional daily mean ETo rates by month using
the regional mean climate data from CIMIS (the California Irrigation Management Information
1.3.4 Water Budget Workbook, Beta Version 1.01 Calculator
By the California DWR, Statewide Integrated Water Management, Water Use
and Efficiency Branch.
This tool can be used to calculate maximum applied water allowance and estimate total water use
for a landscape. The tool utilizes local values for reference evapotranspiration, which are
contained in Appendix A of the California DWR's Model Water Efficiency Landscape Ordinance
1.3.5 WaterSense Water Budget Approach, Version 1.0
By the U.S. EPA WaterSense program.
This document was developed in support of the WaterSense New Home Specification. To meet
the landscape design criterion of the specification, a builder must either:
• use the WaterSense Water Budget Tool to develop the landscape design, or
• provide that turfgrass does not exceed 40% of the landscaped area.
The document defines the data required for the first option and gives the equations used
for calculating baseline conditions, landscape water allowance, and landscape water
requirements. The resource also provides worksheets.
1.3.6 Quantifying Effective Rain in Landscape Irrigation Water Management
By S.E. Moore, Irrisoft, Inc.
The author maintains that managing landscape irrigation requires quantifying both ETc and
effective rainfall. Effective rainfall is the amount of rain a plant can utilize. The moisture-holding
capacity of the soil and current moisture content limit the amount of rain that can be utilized.
Smart controllers often incorporate a rain shut-off device, which may, however, resume watering
sooner than called for. If a smart controller measured both ET and rain, it would not irrigate
during rainfall and would sense when irrigation should resume after a rain. The author used four
factors to quantify effective rain:
• amount of measured rain,
• percolation versus runoff,
• root zone storage, and
• moisture balance.
1.3.7 Turfgrass Irrigation Requirements Simulation in Florida
By M.D. Dukes, Agricultural and Biological Engineering Dept., Univ. of
*Found through search of the Irrigation Association website.
Because residents of Florida have access to various methods for scheduling turfgrass/landscape
irrigation, they often are confused about which method best balances water conservation with
plant needs. For this study, irrigation requirements were simulated for a 30-year period, using a
daily soil-water balance to compare net irrigation requirement, drainage below the root zone, and
the influence of effective rainfall. The authors simulated an optimized irrigation schedule based
on refill of the soil profile when the soil water content reached a stipulated depletion. The
schedule, which emulated the effects of soil moisture sensors and ET controllers, reduced
irrigation requirements by 60% compared to a recommendation of 0.75 inches when turf wilts.
Drainage was reduced accordingly.
1.3.8 Landscape Irrigation Scheduling and Water Management: Draft
By the Water Management Committee of the Irrigation Association.
189 pages, including references and glossary.
March 2005; out for peer review, November 2008.
This document reviews approaches to obtaining efficient, water-conserving landscape irrigation.
Included are basic irrigation concepts, methods for scheduling and water management, quality
ratings for irrigation systems, landscape water allowance, and drought management through
deficit irrigation. Topics include ET, landscape coefficient, net plant water requirement,
irrigation water budget, precipitation rate, optimum irrigation interval, irrigation run time, and
avoiding runoff. The authors describe scheduling (1) based on historical ET, (2) using a rain
shut-off device, and (3) using a soil moisture sensor. They provide equations for calculating
landscape water allowance and applying deficit irrigation.
1.3.9 A Guide to Estimating Irrigation Water Needs of Landscape Plantings in
California: the Landscape Coefficient Method and WUCOLS III
By the University of California Cooperative Extension and California DWR.
This guide offers two formulas for estimating water needs of landscape plants: the landscape
evapotranspiration formula, and the landscape coefficient formula. The landscape coefficient was
developed by modifying the coefficient for crops and turfgrass in order to estimate water needs
of landscape plants. A landscape coefficient (KL) replaces the crop coefficient (Kc).
1.3.10 Appendix E in Urban Water Use in California
By the California Department of Water Resources.
Among other materials, Appendix E, titled “Precipitation and Urban Landscaping,” contains:
• Table E-2, Estimated Values for Species, Density, and Microclimate Factors Used to
Determine the Landscape Coefficient (KL) for Selected Vegetation Types;
• Figure E-1, Annual Precipitation and Per Capita Water Use;
• Figure E-2, Average Maximum July Temperatures and Per Capita Water Use; and
• Figure E-3, Normal Monthly Evaporation and Rainfall for Two Precipitation Zones in the
1.3.11 CIMIS GOES Dish and Receiver Installation
California DWR, Water Use Efficiency: CIMIS.
In December 2012, the California Irrigation Management Information System (CIMIS) installed
a satellite dish and receiver to obtain data from the National Oceanic and Atmospheric
Administration’s Geostationary Operational and Environmental Satellite (GOES). The Spatial
CIMIS model would use the satellite data from more than 140 automated weather stations
Documents you may be interested
Documents you may be interested