Step-by-Step Guide

Understanding Runoff and Its Causes

Runoff occurs when water is applied faster than the soil can absorb it or when more water is applied than the soil can hold. Every drop of water running down a gutter or street in an urban setting represents wasted irrigation. According to EPA WaterSense labeling, 50% or more of water applied to urban landscapes is wasted and not utilized by the plant material it's intended to irrigate.

Several factors contribute to runoff conditions:

• Head types and precipitation rates: Different sprinkler heads apply water at different rates
• Soil type: Denser, harder soils absorb water more slowly
• Percent slope: Steeper slopes increase runoff potential
• Soil compaction: Compacted soil resists water infiltration
• Thatch buildup: Excessive thatch prevents water from reaching the soil
• Overspray: Misadjusted or broken heads waste water

Runoff isn't always visible as water running down the street. Standing water or pooling on the landscape also indicates runoff, meaning water is not penetrating the soil profile as intended. Just because you don't see water running down the street doesn't mean you're watering efficiently.

The second major cause of runoff is applying more water than the soil profile can hold—essentially watering after saturation. Once the soil is holding all the water it can, additional irrigation will either run off the surface or drain out the bottom. In very coarse soils, excess water simply drains through and you'll never see it unless you take specific management steps.

Using Multiple Programs to Prevent Runoff

One of the first and most underutilized strategies for preventing runoff is using multiple programs on your BaseManager 3200 controller. Many users are accustomed to working with only four programs and don't realize what they can accomplish with 99 available programs.

Separate different sprinkler head types and their different application rates into different programs. This approach provides several key benefits:

• You can adjust runtime for individual zones within each program
• You can change the frequency and scheduling for each program independently
• You can group like sprinklers or like plant material together (hydrozoning)
• You can associate each program with appropriate moisture sensors

For example, create separate programs for rotors, spray heads, and drip zones rather than compromising by grouping dissimilar zones together. When you only have four programs available, you're forced to make compromises and put zones together that don't technically belong together. With access to many more programs, you can properly separate zones by their irrigation characteristics.

Programs that are not currently in use will appear grayed out in the interface, indicating they are disabled. This visual cue helps you manage which programs are active.

Implementing Intelligent Cycle and Soak

Intelligent Cycle and Soak is BaseManager's approach to cycle and soak programming and represents the most important tool for preventing runoff. This capability sits at the heart of what BaseManager does and was originally developed to enable proper use of soil moisture sensors.

Basic cycle and soak works by breaking up a total runtime into multiple shorter cycles with soak periods in between. For example, if you have a 45-minute total runtime for rotor zones, you might set a 15-minute cycle time. The system will run for 15 minutes, pause for a soak period (such as 30 minutes), then run another 15-minute cycle, soak again, and complete a final 15-minute cycle. This adds up to your 45-minute total runtime but allows water to infiltrate between applications.

The key columns in the cycle and soak setup are:

• Run Time / Tracking Ratio: The total amount of water you want to apply
• Cycle Time: The longest amount of time a zone will run in one period before pausing
• Soak Time: The pause period between cycles to allow water infiltration

Why Intelligent Cycle and Soak Was Developed

The cycle and soak capability wasn't created simply to give users the ability to break up their watering. It was developed specifically to enable proper use of soil moisture sensors, particularly in upper threshold mode.

When you apply 60 minutes of runtime all at once, there is a period of time before that water reaches the sensor in the ground. If the soil only needs 10 minutes of water, the system needs time for that 10 minutes to reach the sensor and register. Without cycle and soak, the system would apply the full runtime before the sensor could respond.

The intelligence in BaseManager's cycle and soak addresses multiple complex variables simultaneously:

• Multiple water sources on the site
• Multiple main lines
• Zone concurrency requirements
• Hydraulic capacity of the system
• Minimizing the water window
• Preventing zones from being abandoned to evapotranspiration

If a human simply set up cycle and soak and let zones run one at a time in clockwork fashion, zones wouldn't get watered efficiently, you wouldn't maximize your hydraulics and zone concurrency, your water window would expand unnecessarily, and zones would be left too long between cycles, allowing the first application to evaporate.

How Intelligent Cycle and Soak Operates

During the soak period, BaseManager actively looks for other zones to run rather than leaving dead time where nothing happens. This keeps water flowing continuously, maintains pump operation, and prevents your water window from expanding.

Here's how it works in practice:

1. Zone 1 runs for its 15-minute cycle time, then pauses to begin its 30-minute soak period.

2. During Zone 1's soak time, the system immediately looks for another zone to run and starts Zone 3 (the next available zone).

3. Zone 3 runs for 15 minutes. If there are still 15 minutes remaining in Zone 1's soak time, the system runs Zone 4.

4. When Zone 4 completes and Zone 1's 30-minute soak is finished, the system returns to Zone 1 for its second 15-minute cycle.

5. The system continues bouncing between zones, ensuring water is always running and managing hydraulics while respecting each zone's soak requirements.

The critical benefit is that water is always running—the pump doesn't cycle on and off, your water window doesn't expand, and you're managing hydraulics properly while still preventing runoff. You don't have to choose between preventing runoff and maintaining an efficient water window.

Monitoring Cycle and Soak with Quick View

The Quick View screen uses color coding to show you at a glance what's happening with your cycle and soak operation. 

Understanding these color codes helps you quickly diagnose system operation:

• Dark Blue: Zone is actively watering right now
• Light Blue: Zone is in its soak period (has completed a cycle and is waiting before the next cycle)
• Yellow: Zone is waiting to water and has not yet started its first cycle
• Pink: Zone is paused (typically because a higher priority program has started)

For example, if you see zones 2, 6, 8, 11, 18, and 22 in light blue, zone 25 in dark blue, and zones 28, 31, and 33 in yellow, you know that the light blue zones have already run their first cycle and are soaking, zone 25 is currently watering, and the yellow zones haven't started yet.

This visual feedback is especially valuable because zones don't run in simple sequential order. BaseManager performs what's sometimes called "the BaseManager dance"—running zones in whatever order best meets the hydraulic needs of the site, not necessarily in numerical sequence. If a higher priority program needs to run, all zones from the current program will turn pink and pause, the higher priority program will complete its operation (including its own cycle and soak), and then the previous program will resume where it left off.

Integrating Soil Moisture Sensors with Cycle and Soak

Soil moisture sensors play a critical role in preventing runoff, though the sensor itself doesn't directly prevent runoff—it's a sensing device that collects data. The sensor doesn't control runtimes, start times, or days of the week unless you set up the program accordingly. However, sensors allow you to see the results of your watering and how well your cycle and soak strategy is working.

When you associate a soil moisture sensor with a zone or program in BaseManager, the system forces you into a cycle and soak strategy by default (unless you override it). This is intentional and critical for proper sensor operation.

Using Upper Threshold Mode to Prevent Overwatering

Upper threshold mode is particularly important for preventing runoff. In this mode, the system fills the soil profile to field capacity (as much as it will hold) and then prevents watering beyond that point, even if more runtime remains.

Upper threshold operates on cycles rather than completing full runtimes. If the sensor indicates the soil profile is full but the zone still has runtime remaining, the system stops watering rather than topping off and creating runoff.

Your cycle time becomes your resolution—how tightly you want to control water application. Shorter cycle times provide more opportunities for tighter control. If you overwater, it will only be by the length of one cycle rather than a much longer period.

For example, if you have extremely tight, hard-packed clay soil, you could set up a 1-minute cycle with a 5-minute soak for a 60-minute total runtime. The system will pulse water into the soil very slowly over time. This same approach works effectively for green roofs or drain walls.

Conversely, if you set a 30-minute cycle time and the soil profile fills up after only 10 minutes, the system will complete the entire 30-minute cycle, resulting in 20 minutes of runoff and wasted water. This is why cycle time resolution is so important.

The beauty of using sensors with upper threshold is visible in the moisture graphs over time. If you see that you keep watering above the threshold, it's likely because your cycles aren't set up correctly. The system is applying a whole cycle when only a portion is needed. You need to tighten up the cycle time and add more soak time to prevent this waste.

Using Lower Threshold Mode with Cycle and Soak

While upper threshold is the primary mode for preventing excess water and runoff, you can also use lower threshold with cycle and soak. The approach is slightly different.

With lower threshold and cycle and soak, increase the number of start times available for the program. For example, set start times for 7:00 AM, 1:00 PM, and 8:00 PM. The system operates as follows:

• If the soil has dried out by 7:00 AM, the first cycle runs
• At 1:00 PM, the system checks again; if the soil hasn't dried below the threshold, it skips that start time
• At 8:00 PM, if the soil has dried below the threshold, that cycle starts

This provides flexibility in how you apply cycle and soak using sensor technology. You just need to be creative in your approach, and it all comes back to thinking outside the traditional start time.

Determining Appropriate Soak Times

There are several methods for determining the correct soak time for your zones:

Scientific Calculation: The Irrigation Association provides detailed algorithms that account for soil type, slope, and other factors to calculate soak time to the second. This method is technically precise but time-consuming.

Weather Access Predictive Calculation: When using Weather Access in BaseManager, you enter zone properties including sprinkler type, percent slope, soil type, and other parameters. The system then calculates a predictive cycle and soak recommendation, telling you how long the sprinkler can run before runoff will start and providing a recommended soak time based on all the parameters. BaseManager gives you the ability to automatically apply these recommendations.

Direct Observation: The simplest method is to run your zone and observe it. Watch the zone operate and note when you start seeing water run off. Back up from that point—that's your cycle time. For soak time, you'll need to observe how long it takes for standing water to infiltrate or use moisture sensor graphs to see how long water takes to reach the sensor depth.

Each zone may require different cycle and soak times based on its specific conditions. In clay soils, it can take hours for water to infiltrate to where a sensor located three or four inches below grade can detect it.

Using Moisture Sensor Graphs to Refine Settings

Moisture sensor graphs provide valuable feedback for refining your cycle and soak settings. By increasing the resolution of the graphing capability, you can see exactly how long it takes for an application of water to infiltrate the soil profile to the sensor depth.

Watch for these patterns in your graphs:

• If moisture levels consistently exceed your upper threshold, your cycle times are too long
• If there's a significant delay between irrigation start and moisture increase at the sensor, you may need longer soak times or shorter cycles
• If moisture drops rapidly between cycles, your soak time may be too long for your conditions

This visual feedback allows you to dial in your settings precisely for each zone's unique conditions.

On-Demand Watering Without Start Times

For subsurface drip systems or other applications where you want truly on-demand watering, you can set up a program to run based solely on moisture sensor thresholds without any scheduled start times. The system will initiate an irrigation cycle only when the sensor indicates the soil has dried to the threshold level.

This approach works particularly well for drip irrigation because:

• Drip can run at any time without affecting people or activities
• Subsurface or on-surface drip has minimal drift concerns
• The system responds precisely to actual plant water needs rather than a predetermined schedule

To implement this, simply set up your program with sensor thresholds but no start times. The sensor will trigger irrigation cycles as needed based on actual soil moisture conditions.

Video Walkthrough

Video originally published January 2021.

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