KEEPING LANDSCAPES GREEN

Transcription

1 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

2 Dennis Pittenger Area Environmental Horticulturist Phone: CENTER FOR LANDSCAPE & URBAN HORTICULTURE < 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

3 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

4 Average California Water Use Statewide Developed Water 20% Urban & 9% Landscape 6% 7% 2% 4% 1% 3% Agriculture Indoor Residential Outdoor Residential Large Landscape Comm'l/Inst'l/Inds'l 77% 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.

5 California Statewide Urban Water Use Average, Source: Calif. Dept. Water Resources, 2013 Calif. Water Plan Update Chp. 3

6 Essentiality of Landscape Water Function Recreation Aesthetics Mental Well-being Los Angeles County/UC Riverside

7 Many Landscapes Are Overwatered!!!

8 Landscapes Are Under Attack!!! 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

9 Estimating Landscape Plant Water Requirements

10 One-word term describing water use of a planted area due to soil evaporation and plant transpiration. EVAPOTRANSPIRATION (ET)

11 Plant water use is driven primarily by the energy from the. SUN

12 Water needs of a particular landscape plant can be accurately estimated simply by knowing its plant type category (turf, tree, shrub, groundcover, etc.) TRUE

13 Evapotranspiration (ET)

14 ETo = Reference Evapotranspiration An estimate of environmental water demand over a planted area 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

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16 Estimating Landscape Water Requirement Accurate and Simple Equation Gallons = ETo PF LA 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.)]

17 Estimating Plant Water Needs Through Science

18 Using & Adjusting PF & Kc Values Turf Gc-Sh-Tr-Fl More Leaves & Growth High Expectations C W 0.20 Less Leaves & Growth Low Expectations 0.00 Copyright D. Shaw and D. Pittenger Center for Landscape & Urban Horticulture University of California Cooperative Extension

19 Simplified Landscape Irrigation Demand Estimation S L I D E..for selecting Plant Factors

20 SLIDE Paradigm 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

21 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

22 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

23 Applying SLIDE Rules Established Landscapes Landscape Water Budget or Water Need Gallons = ETo (PF LA) 1-x = (PF 1 LA 1 )+ (PF 2 LA 2 ) + (PF 3 LA 3 ).. 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.)]

24 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 ) DU Turf Requirement (gal.) = (44 in ,000 sq. ft ) 0.6 = 365,493 gal. = 59 in. Mixed Beds Requirement Gallons = ( , ) 0.9 = 53,301 gallons = 24 inches Site Water Budget = 418,794 gallons

25 Isolated Trees Use Canopy Area for Landscape Area Gallons = ETo PF Canopy Area Canopy Area (sq. ft.) = 3.14 (radius radius)

26 Source: 2014 American Forests Estimating Canopy Area

27 Useful Equations Inches = Gallons (Sq. Ft ) Gallons = Inches Sq. Ft Billing Unit = HCF = 748 Gal. Los Angeles County/UC Riverside

28 WUCOLS Water Use Classification of Landscape Species

29 SLIDE Rules Landscape Coefficient (K L ) K L = K PLANTS K VEG. DENSITY K MICROCLIMATE

30 Cost Effective Strategies & Actions Horticultural Practices to Aid Water Conservation Irrigation System Management & Maintenance Hardware Improvements Landscape Design, Expectations, Retrofits

31 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

32 Turf Aeration Increases water and air entry into soil Reduces thatch Reduces compaction

33 Horticultural Practices to Aid Water Conservation Keep irrigation heads clear Forgo exotic products! Los Angeles County/UC Riverside

34 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

35 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

36 Effective Irrigation Apply amount of water needed by plants Plus extra water for: Non-uniform distribution Salt management

37 Effective Irrigation Management Distribute water uniformly Affected by system: Design Installation Maintenance

38 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

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41 Distribution Uniformity (DU) DU Irrigation Multiplier

42 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 ) DU Turf Requirement Gallons = ( , ) 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)

43 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

44 Effective Irrigation Management Avoid runoff Affected by: Site conditions Horticultural practices Irrigation system operation, mgt., maintenance

45 Avoid Runoff Site Conditions Slope Landscape design Irrigation system

46 Avoid Runoff Horticultural Practices Avoid soil compaction Aerate/dethatch turf Dethatch turf

47 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!

48 Avoid Runoff Multiple start times Cycle and soak Run irr. laterals across slope Reduce precipitation rate

49 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

50 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?

51 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

52 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

53 Irrigation System Evaluation

54 Irrigation System Evaluation

55 Good Maintenance Yields Improved Effectiveness Be wary of in-field modifications!!

56 Hardware Improvements Smart controller? 4+ programs/4+ starts Precision, Press. Comp. emitters No silver bullets Integrated approach needed Improve system performance and management first!!

57 Landscapes require irrigation when....performance expectations exceed plant adaptation to precipitation Expectations and Design Intent determine landscape water need

58 Landscape Design, Expectations, Retrofits Hydrozones Maximize irr. system performance High uniformity and no runoff Reduce turf - Functional turf only Low expectation/low density zones

59 Landscape Design & Expectations Expectations Met and Water Conserved

60 Turf replacement Landscape Retrofits Difficult to irrigate areas

61 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?

62 Prioritizing Irrigation Focus water on most valuable & difficult to replace plants Trees/Shrubs/Vines/Grdcvr > Perennials > Lawn/Annuals

63 Prioritizing Irrigation

64 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 in. every days Perennials 1.0 in. every 5-7 days But how long can they go??

65 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.

66 Dennis Pittenger Area Environmental Horticulturist Phone: Center for Landscape & Urban Horticulture < Los Angeles County/UC Riverside

67 Useful Reference Materials U.C.C.E. Center for Landscape and Urban Horticulture (Landscape Water Management tab on left) Irrigation Association s Landscape Irrigation Auditor Man l. 2 nd Ed. (2011) or 3 rd Ed. (2013). Chapter 7 and Appendix D. U.C. Cooperative Extension Handbook: Landscape Irrigation System Evaluation and Management. (D. Shaw and D. Pittenger, 2009) (Landscape Water Management tab on left) California Dept. of Water Resources CIMIS CIMIS (California Irrigation Management Information System) Los Angeles County/UC Riverside