landscape irrigation system evaluation and management may 17, 2014 mendocino college paul zellman

Landscape IrrigationSystem Evaluation and

Management

May 17, 2014

Mendocino College

Paul Zellman

Landscape IrrigationOverview

Goal of good irrigation management:

Supply plant materials the: correct amount of water, at the proper time.

Maintain irrigation systems for peak performance

Make careful decisions on when and how much to irrigate.

Paul Zellman paulzellman.com Vineyard and Landscape Consulting

Efficient Irrigation Water Management

Quality Hardware: design, installation.

Vigilant Maintenance: regular monitoring (weekly, bi-weekly, ???) timely repairs

Weather-based Irrigation Schedules Controllers updated weekly based on local weather.


Effective Landscape Irrigation

Irrigation systems should be designed, installed, and maintained to distribute water as uniformly as possible.

Irrigation system should be operated long enough to apply a depth of water equal to the water use of the landscape plus extra to compensate for the non-uniformity of the system.

The irrigation system should be designed, maintained, and operated to avoid runoff.


Steps to Develop a Landscape Irrigation Schedule

1. Walk-through Inspection & make necessary repairs (Weekly?)

2. Precipitation Rate (PR) & Distribution Uniformity (DU)

3. Understand the Water Needs of your landscape plant

4. Calculate station Run Times to meet the water needs of the landscape.

5. Decide the Frequency of Irrigation and if "cycling" is necessary

6. Verify the irrigation schedule with field observations and adjust if necessary.


Step 1. Walk-through Inspection BTW – I love my Hunter remote control.


20% to 50% of water savings is found here

Broken parts & plant growth blocking water spray

Irrigation HardwareController, wiring, valves, rainfall & soil sensors, pressure regulators

Soils - ponding, thatch, compaction

Physical Problems

Broken components, Heads / Nozzles mismatched, uneven spacing

Wrong spray pattern, sunken heads, worn nozzles, unequal pressures, heads not vertical / perpendicular to slope, clogged, not turning, low-head drainage.

Step 1. Walk-throught Inspection


Step 1. Walk-through Inspection


Step 2. Irrigation System Precipitation Rates and Distribution Uniformity


Once the "walk-through" inspection is completed and the necessary repairs have been made,

Performance of the system can be evaluated

*Precipitation Rate (PR)

*Distribution Uniformity (DU).

GPM x 96.3

PR (In/Hr) = ────────────────────────

Landscape Area in square feet

Average of the Low Quarter

DU = ────────────────────────

Average of All Measurements

Step 2. Catch Can – PR & DU


Step 2. Catch Can: PR & DU



Step 2. Irrigation System PR & DU

Step 3. Water Needs of Turfgrasses


ETo x Kc = Plant ET

Turfgrasses

Crop coefficients (Kc): cool-season 0.80 (0.60)vs. & warm- season 0.60 (.35)

Cool season: tall fescue, ryegrass, bentgrass, and Kentucky bluegrass.

Warm season: bermudagrass, zoysiagrass, buffalo and St. Augustinegrass.

**Save 25% of water by using warm season grasses (*winter brown => over seed)

Step 3. Water Needs of Turfgrass and Landscape Plant Materials


Step 3. Water Needs of Landscape Plant Materials


Steps to Develop a Landscape Irrigation Schedule on

your Irrigation Controller1. Set controller Date and Time

2. Set Stations with Programs to match Plant Water Needs Groupings:

e.g. Program A = Turf; B = Shrubs – North; C = Shrubs – South; D = Deck Pots.

3. Set Days of Week to Irrigate, e.g. once per week or daily (pots vs. turf)

4. Set Run Times to meet the water needs of the landscape.

5. Set Start Times: If runoff occurs, set two or more run times.

Station Runtime (minutes per week) = Days per week X Run Time X Start Times


Step 4. Calculate Station Run Times


Station Run Times Individual station run times are determined from both plant water use estimates (ET) and the system PR and DU on a daily, weekly, or monthly basis: 1) The Precipitation Rate (PR) of the irrigation system in inches/hour. 2) The Distribution Uniformity (DU) of the irrigation system. The DU is used as an estimate of the irrigation efficiency (IE). DU will account for the losses due to non-uniformity of irrigation. IE accounts for uniformity, runoff, and deep percolation losses. 3) Historical or Real Time Evapotranspiration (ETo) Information. 4) Crop Coefficient (Kc) Values:

ETo x Kc x 60 RUN TIME (minutes) = ──────────────────

PR x DU

Step 5. Frequency of Irrigation: is “cycling” necessary?


Is there surface water runoff with calculated runtimes?

If yes: you must schedule two or more runtimes.

Step 6. Verify that your schedule meets your plant needs.

If not, adjust run times.

*** Use you controller adjustment feature:“Seasonal Adjustment”, “ETo”, etc..

How are your plants doing?


Step 7.

Relax.

This is not rocket science.

The Russian River Flood Control District is not out to get you…perhaps your neighbor...


Reference Materials and Sources of Information

Irrigation Scheduling - Publication 21454Basic Irrigation Scheduling - Leaflet 21199Turfgrass Water Conservation - Publication 21405Reference Evapotranspiration for California - Bulletin 1922Determining Daily Reference Evapotranspiration - Leaflet 21426Using Reference Evapotranspiration and Crop Coefficients to Estimate CropEvapotranspiration: Agronomic Crops, Grasses and Vegetable Crops - Leaflet 21427Trees and Vines - Leaflet 21428Turfgrass Irrigation Scheduling - Leaflet 21492Evaluating Turfgrass Sprinkler Irrigation Systems - Leaflet # 21503Farm Irrigation System Evaluation: A Guide for Management.1978. J.L. Meriam and J. Keller.Landscape Water Management Handbook. DWR Office of Water Conservation. 1987.R.E. Walker and G.J. Kah University of California Sites:Dr. Richard Snyder’s U. C. Davis weather and irrigation scheduling information site:http://biomet.ucdavis.edu/index.phpDennis Pittenger’s U.C. Riverside web page with landscape management information:http://plantbiology.ucr.edu/coop.html (scroll to “Dennis Pittenger” link).


landscape irrigation system evaluation and management may 17, 2014 mendocino college paul zellman

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