eeping landscapes reen with less green...landscape water management tab on left) • irrigation...
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KEEPING LANDSCAPES GREEN WITH LESS GREEN
Dennis Pittenger, M.S. Area Environmental Horticulturist
University of California Cooperative Extension
Los Angeles County/UC Riverside
Presentation © 2014 Dennis Pittenger
Dennis Pittenger Area Environmental Horticulturist dennis.pittenger@ucr.edu Phone: 951.827.3320 CENTER FOR LANDSCAPE & URBAN HORTICULTURE <www.ucanr.edu/cluh>
• B.S. & M.S. Horticulture, Ohio State University • 33 years experience
– Landscape & urban horticulture – Education and applied research programs – Landscape irrigation mgt., plant water needs,
weather-based irrigation control – Presentations, workshops, publications, Web
. • Los Angeles County/UC Riverside
Objectives
• Learn a simple, accurate climate-based method to estimate landscape water requirements.
• Understand cost-effective strategies for minimizing landscape irrigation.
• Learn how to prioritize irrigation when water is limiting
• Los Angeles County/UC Riverside
Average California Water Use Statewide Developed Water
20% Urban & 9% Landscape
77%
6%
7% 2% 4% 1%
3% Agriculture
Indoor Residential
Outdoor Residential
Large Landscape
Comm'l/Inst'l/Inds'l
Other
Environmental
Sources: Calif. Dept. Water Resources, 2013 Calif. Water Plan Update Chp. 3. UCLA Inst. of Env’t. and Sustainability, So. Calif. Environ’l. Report Card, Fall 2009.
California Statewide Urban Water Use Average, 1998-2005
Source: Calif. Dept. Water Resources, 2013 Calif. Water Plan Update Chp. 3
Essentiality of Landscape Water
• Function • Recreation • Aesthetics • Mental Well-being
• Los Angeles County/UC Riverside
Many Landscapes Are…
Overwatered!!!
• Drought is official • Perception:
• Landscapes are non-essential • Landscapes waste water
• Less or NO water for landscapes • We must be efficient water managers!
• Los Angeles County/UC Riverside
Landscapes Are Under Attack!!!
Estimating Landscape Plant Water Requirements
One-word term describing water use of a planted area due to soil evaporation and plant transpiration.
EVAPOTRANSPIRATION (ET)
Plant water use is driven primarily by the energy from the ____________.
SUN
Water needs of a particular landscape plant can be accurately estimated simply by knowing its plant type category (turf, tree, shrub, groundcover, etc.)
TRUE
Evapotranspiration (ET)
Climate-based reference Inches/day ETo = estimated water use of
well-watered cool-season turf Calculated from weather data
Sunlight, temperature, RH, wind
ASCE Penman-Monteith equation
Based on field research with agricultural crops
ETo = Reference Evapotranspiration An estimate of environmental water demand
over a planted area
Estimating Landscape Water Requirement
Accurate and Simple Equation
Gallons = ETo × PF × LA × 0.623 gallons = inches × % × sq. ft. × conversion
ETo = reference evapotranspiration; climate impact PF = plant material adjustment factor
LA = sq. ft. landscape area 0.62 = converts depth to volume [gal. ÷ (in. x sq. ft.)]
Estimating Plant Water Needs Through Science
Center for Landscape & Urban Horticulture University of California Cooperative Extension
Using & Adjusting PF & Kc Values
0.00
0.20
0.40
0.60
0.80
1.00
W
C
More Leaves & Growth High Expectations
Less Leaves & Growth Low Expectations
Turf Gc-Sh-Tr-Fl
Center for Landscape & Urban Horticulture University of California Cooperative Extension
Copyright © 2010-2013 D. Shaw and D. Pittenger
Simplified Landscape Irrigation Demand Estimation
S L I D E
…..for selecting Plant Factors
Principles: Plant factors accurately
estimated by broad plant type categories based on science and research
Landscape water need estimated by weighting sq. ft. of each plant type present
SLIDE Paradigm
SLIDE Features Simple to understand & use
Replaces need for huge data base Reduces number of factors or variables
Accommodates new plants Scientifically & conceptually sound
Assimilation and application of ≈20 yrs. of data Scientifically traceable
Provides reliable numbers for calculations Wide geographic & climatic application
SLIDE Rules (DRAFT)
Water Requirements of Plant Categories Turfgrass = 60% (40%) ETo (w-s) / 80% (60%) ETo (c-s) Tree/Shrub/Groundcover/Vine = 50% (30-40%) ETo Herbaceous Perennial Flowers/Foliage = 70% (50%) ETo Annual Flowers/Foliage = 80% (60) ETo Low Expectations/Native Adapted = 30% (20%) ETo
Applying SLIDE Rules Established Landscapes
Landscape Water Budget or Water Need Gallons = ETo × ∑(PF × LA)1-x × 0.623
∑ = (PF1 × LA1)+ (PF2 × LA2) + (PF3 × LA3)….. Divide each zone by its DU
• ETo = reference evapotranspiration, CIMIS, etc.; climate impact • PF = plant material factor (turf, shrub-tree-vine-gc, flowers, etc.)
• LA = sq. ft. landscape area • 0.62 = converts depth to volume [gal. ÷ (in. x sq. ft.)]
Applying SLIDE #1 Landscape Site
• 10,000 sq. ft. of tall fescue general turf (cool-season) • 3,500 sq. ft. of mixed beds with various trees, shrubs, groundcovers • Annual ETo is 44 inches
Annual Water Requirement (gal.) = (ETo × AF × Sq. Ft. × 0.623) ÷ DU
Turf Requirement (gal.) = (44 in. × 0.8 × 10,000 sq. ft. × 0.623) ÷ 0.6 = 365,493 gal. = 59 in. Mixed Beds Requirement Gallons = (44 × 0.5 × 3,500 × 0.623) ÷ 0.9
= 53,301 gallons = 24 inches • Site Water Budget = 418,794 gallons
Isolated Trees Use Canopy Area for Landscape Area
Gallons = ETo × PF × Canopy Area × 0.623 Canopy Area (sq. ft.) = 3.14 × (radius × radius)
Estimating Canopy Area
Source: © 2014 American Forests
Useful Equations
Inches = Gallons ÷ (Sq. Ft. × 0.623)
Gallons = Inches × Sq. Ft. × 0.623
Billing Unit = HCF = 748 Gal.
• Los Angeles County/UC Riverside
WUCOLS Water Use Classification of Landscape Species
KL = KPLANTS × KVEG. DENSITY × KMICROCLIMATE
Landscape Coefficient (KL)
SLIDE Rules
Cost Effective Strategies & Actions
• Horticultural Practices to Aid Water Conservation • Irrigation System Management & Maintenance • Hardware Improvements • Landscape Design, Expectations, Retrofits
Horticultural Practices to Aid Water Conservation
• Aerate turf • Raise mowing height • Reduce fertilizer
– Slow release N
• Mulch exposed soil • Avoid heavy pruning
• Los Angeles County/UC Riverside
Turf Aeration
• Increases water and air entry into soil
• Reduces thatch • Reduces compaction
Horticultural Practices to Aid Water Conservation
• Keep irrigation heads clear • Forgo exotic products!
• Los Angeles County/UC Riverside
Landscape Irrigation System Management & Maintenance
Goal: supply plants with right amount of water at proper time as efficiently as possible
• Los Angeles County/UC Riverside
7 Habits of Highly Effective Water Managers
1. Accurately estimate landscape water requirement 2. Apply right amount of water at right interval 3. Maintain highly uniform irrigation system 4. Eliminate runoff & deep percolation 5. Irrigate when wind & evaporation are minimum 6. Evaluate/maintain hardware and landscape often 7. Adjust/evaluate schedules as conditions change
• Los Angeles County/UC Riverside
Effective Irrigation
• Apply amount of water needed by plants
• Plus extra water for: – Non-uniform distribution – Salt management
Effective Irrigation Management
• Distribute water uniformly
• Affected by system: – Design – Installation – Maintenance
Distribution Uniformity (DU)
• A measure of how evenly water is applied to a crop.
• Based on measurements which can be readily made.
• Affected by system design and maintenance. • Significantly affects water requirement
• Plant water requirement ÷ DU = Irrigation requirement
Distribution Uniformity (DU)
DU Irrigation Multiplier 0.5 2.00 0.6 1.67 0.7 1.43 0.8 1.25 0.9 1.11
Applying SLIDE #2 Landscape Site
• 10,000 sq. ft. of general turf - with irrigation system improvements • 3,500 sq. ft. of mixed beds with various trees, shrubs, groundcovers • Annual ETo is 44 inches
Annual Water Requirement (gal) = (ETo × AF × Sq. Ft. × 0.623) ÷ DU
Turf Requirement Gallons = (44 × 0.8 × 10,000 × 0.623) ÷ 0.7 = 313,280 gal. = 50 inches
Reduced Turf Water Budget ≈ 15% (313,280 gal vs. 365,493 gal or 50 in vs 59 in)
Focus on Maximizing DU!!
• Adjust/repair/replace heads or emitters • Add heads or emitters • Optimum pressure for heads and emitters • Goal:
≥70% DU for overhead systems ≥85% DU for drip
Effective Irrigation Management • Avoid runoff • Affected by:
– Site conditions – Horticultural practices – Irrigation system operation, mgt.,
maintenance
Avoid Runoff
• Site Conditions – Slope – Landscape design – Irrigation system
Avoid Runoff
• Horticultural Practices – Avoid soil compaction – Aerate/dethatch turf – Dethatch turf
Avoid Runoff • Horticultural Practices (cont.)
– Keep irr. heads clear • Turf cutting ht./raise heads • Prune/remove plant
– Judicious fertilization & use slow-release N
– Forgo exotic products!
Avoid Runoff • Multiple start times • Cycle and soak • Run irr. laterals across slope • Reduce precipitation rate
Evaluating Landscape Irrigation System & Management
Goals
• Measure effectiveness and efficiency of irrigation system and schedules
• Improve water conserving irrigation schedules and management practices
• Verify Smart Controller performance
Evaluating Landscape Irrigation System & Management
Questions • How efficient and effective am I irrigating my
landscape? • What can I do to conserve water and improve
my irrigation management? • Could a Smart irrigation controller help? • Is my Smart controller performing correctly?
Evaluating Landscape Irrigation System & Management
Process
• Walk-thru inspection & tune-up (maintenance) • Collect data about site & system • Run calculations & analyze data • Report findings • Modify and adjust system & schedules
Evaluating Landscape Irrigation System & Management
Data & Calculations • Verify irrigation zones or stations • Precipitation rate (PR) • Distribution uniformity (DU) • Record plant material, root depths, soil texture • Estimate plant water requirements • Calculate schedule for each zone or station
Irrigation System Evaluation
Irrigation System Evaluation
Good Maintenance Yields Improved Effectiveness
Be wary of in-field modifications!!
Hardware Improvements
• Smart controller? • 4+ programs/4+ starts • Precision, Press. Comp. emitters • No silver bullets • Integrated approach needed • Improve system performance
and management first!!
Landscapes require irrigation when…..
…..performance expectations exceed plant adaptation to precipitation
Expectations and Design Intent
determine landscape water need
Landscape Design, Expectations, Retrofits
• Hydrozones • Maximize irr. system performance
– High uniformity and no runoff
• Reduce turf - Functional turf only • Low expectation/low density zones
Landscape Design & Expectations
• Expectations Met and Water Conserved
Landscape Retrofits • Turf replacement • Difficult to irrigate areas
What About Sports Fields??
• Priority? • Highest water requirement
– Need to be actively growing – Turf must recover from wear – Injury potential
• Is artificial turf cost-effective?
Prioritizing Irrigation
• Focus water on most valuable & difficult to replace plants • Trees/Shrubs/Vines/Grdcvr > Perennials > Lawn/Annuals
Prioritizing Irrigation
Approx. Minimum Water Required to Keep Plants Alive
• Lawns – c-s: 0.5 inches every 3-5 days – w-s: 0.75 in. every 7-10 days
• Trees/Shrubs/Vines/Groundcovers – 1.0-1.5 in. every 10-14 days
• Perennials – 1.0 in. every 5-7 days
But how long can they go??
Take Home Highest ROI Priorities
• Landscape & Irr. Sys. Maint. • Improve DU and hardware • Improve schedules • Lower expectations • Reduce planted area • Prioritize irrigated areas • Retrofit/adjust plant spp. mix
– Turf = 31 gal./sq. ft. – G-S-T = 16 gal./sq. ft. – Color = 25 gal./sq. ft.
Dennis Pittenger Area Environmental Horticulturist
dennis.pittenger@ucr.edu Phone: 951.827.3320 Center for Landscape & Urban Horticulture <www.ucanr.edu/cluh>
• Los Angeles County/UC Riverside
Useful Reference Materials • U.C.C.E. Center for Landscape and Urban Horticulture
– www.ucanr.edu/cluh (Landscape Water Management tab on left)
• Irrigation Association’s Landscape Irrigation Auditor Man’l. 2nd Ed. (2011) or 3rd Ed. (2013). Chapter 7 and Appendix D.
• U.C. Cooperative Extension Handbook: Landscape Irrigation System Evaluation and Management. (D. Shaw and D. Pittenger, 2009) – www.ucanr.edu/cluh (Landscape Water Management tab on left)
• California Dept. of Water Resources – CIMIS – CIMIS (California Irrigation Management Information System) – http://www.cimis.water.ca.gov/cimis
• Los Angeles County/UC Riverside
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