Programs A program is a set of watering instructions or a watering schedule, including... Days to be watered... Start times... Stop times... Run times or durations

Programs Controllers with multiple programs allow increased flexibility... Also allow multiple start/run times per station... Program are typically continuous from start to finish

Start Times The number of times a controller can signal the stations or irrigation valves per day... Cheaper controllers have fewer start times Multiple start times allow for greater flexibility... Particularly in specialized settings ex.: newly planted turf slope plantings greenhouses and mist houses

Watering Cycles A complete set of irrigation instructions is implemented during a cycle, including... Start times Run times Run days

Watering Cycles A complete set of irrigation instructions is implemented during a cycle, including... Start times Run times Run days

Watering Cycles Typical watering cycles are 7 days, 14 days and 15 days 7 day watering cycles limit possible programs 7 day clocks allow for daily watering but not every other day or every 3rd day

Watering Cycles 14 day and 15 day watering cycles allow greater flexibility for programming 14 day clocks allow for watering every day or every other day 15 day clocks allow for every day watering, every 3rd day or every 5th day

Run Days Selected days the irrigation program will operate Some controllers allow choices of... every day... every other day... every third day or... selected days

Run Days Many controllers default to an every day watering cycle in the event of power or battery failures

Station Run Times Most controllers have run times from 1 to 120 minutes Many controllers allow stations to run in minutes or hours for greater flexibility

Station Run Times Specialized controllers have shorter run times of 1 to 60 seconds... Drip irrigation and... Greenhouse / nursery production... Or for several hours for agricultural use

Determining Irrigation Runtimes Locate all necessary information, including: Nozzles and operating pressure Demand Area of hydrozone Soil type and permeability rate number ET O s Number of irrigation days available

Texture vs. Precipitation Rain Bird Design Manual pg. 105

Climate PET Table According to the Climate Pet table ( Rain Bird Design Manual pg.19 ) – we live in a warm dry climate

Precipitation Rate (in/hr) Determine the precipitation rate (PR) in inches/hour (in/hr) 96.3 x demand = PR in/hr Area (in sq.ft.)

Precipitation Rate (in/min) Convert PR from in/hr to inches/minute (in/min) PR in/hr = PR in/min 60 min/hr

Weekly Demand (in/wk) Determine weekly demand in minutes/week (min/wk) Based on the ET O s and nozzles chosen, this number will determine how long the system must run weekly ET O = Weekly Demand min/wk PR in/min

Runoff Time (in/hr) Determine “Runoff Time” in in/hr intervals uses the soil permeability number found on page 105 in the Rainbird Irrigation Design Manual This number determines how long the system can run before runoff occurs Soil Perm # in/hr = Runoff Time in/hr/Interval PR in/min

Texture vs. Precipitation Rain Bird Design Manual pg. 105

Runtime per Day Determine irrigation “Runtime” per irrigation day in min/irrigation day Determining available irrigation days per week (1 to 7 days), This number determines how many minutes the system must run per irrigation day Weekly Demand = Runtime Min/irrigation Day # Irrigation Days/wk

Number of Runtime Cycles per Day Determine number of intervals or cycles per irrigation day Number tells how many times per irrigation day the system must operate to compensate for soil type and slope If the number is less than one – the system requires only one irrigation cycle per day Min/Irrigation Day = # Cycles/Irrigation Day Runoff time Round up to whole number

Length of Runtime Cycles Determine the runtime duration per irrigation cycle per irrigation day This number determines how long each cycle per day must run to meet the demand Runtime/Day = Runtime/Cycle # Cycles/Day Round down to whole number

Example Plant type: Turf ETo: 1.5 in/wk Demand: gpm Area: 2, sq.ft Soil type: Silt loams over compact subsoil w/ 5% to 8% slope Permeability rate: 0.5 in/hr

Precipitation Rate (in/hr) 1) Determine the precipitation rate (PR) in inches/hour (in/hr) PR in/hr = 96.3 x demand = 1.77 in/hr Area (in sq.ft.)

Precipitation Rate (in/min) 2) Convert PR from in/hr to inches/minute (in/min) PR in/min = PR in/hr = 1.77 in/hr = 0.03 in/min 60 min/hr 60 min/hr Our precipitation rate for this system is 0.03 inches per minute.

Weekly Demand (in/wk) 3) Determine weekly demand in minutes/week (min/wk) Weekly Demand min/wk = ET O = 1.5 in/wk = 50 min/wk PR in/min 0.03 in/min This calculation shows that to apply the desired 1.5 inches of irrigation to the turf area using the nozzles we selected, we need to water for 50 minutes per week.

Runoff Time (in/hr) 4) Determine “Runoff Time” in in/hr Runoff Time in/hr/Interval = Soil Perm # in/hr = 0.5 in/hr = 16.7 min/hr PR in/min 0.03 in/min Because of the soil type and the slope, we can only irrigate for 16.7 minutes per hour.

Runtime per Day 5) Determine irrigation “Runtime” per irrigation day in min/irrigation day Runtime Min/irrigation Day = Weekly Demand = 50 min/wk = 25 min/irrig day # Irrigation Days/wk 2 days/wk Because we can only irrigate two days per week, this calculation show that we need to irrigate for 25 minutes per irrigation day.

Cycles per Irrigation Day 6) Determine number of intervals or cycles per irrigation days # Cycles/Irrigation Day = Min/irrig day = 25 min/irrig day = 1.5 or 2 cycles/irrig day Runoff time 16.7 min/hr This tells us that based on the slope and soil type we need to break up our irrigation day into two cycles.

Runtime per Cycle 7) Determine the runtime duration per irrigation cycle per irrigation day Runtime/Cycle = Runtime/Day = 25 min/day = 12.5 min runtime/cycle # Cycles/Day 2 cycles/day Based on the calculations, we need to break up the 25 minute per irrigation day into two runtimes of 12.5 minutes per irrigation day. We could round down to two runtimes of 12 minutes per runtime or make one runtime 12 minutes and the other 13 minutes.