How to Prepare for Irrigation During Water Shortages

Agdex#:	753/77
Publication Date:	07/99
Order#:	99-023
Last Reviewed:	07/99
History:	Original Factsheet
Written by:	Jim P. Myslik - Engineer (Water Management Specialist)/OMAF

Table of Contents

Introduction

1. I have an irrigation system that works well. What more can I do?
2. I irrigate from a stream, as do my neighbours. If we all irrigate at the same time there may not be enough water. What can I do?
3. What else can I do?
4. What if I still do not have enough water to irrigate all my crops?
5. If I irrigate directly from a water well, what can I do?
6. I have a trickle irrigation system which is supposed to be very water efficient. Do I need to do anything?
7. I think there should be more water in the stream. I am concerned that someone is using too much water. What can I do?
8. Useful References
   

Introduction

This Factsheet provides general information on how to use your irrigation equipment efficiently and what you can do if water supplies run short. There is a wide range of crops grown and numerous irrigation systems used to irrigate them. Each combination cannot be dealt with individually. It is up to you to apply and use these principles for your individual operations.

NOTE: You must have a "Permit to Take Water" issued by the Ministry of the Environment to irrigate more than 50,000 litres of water in a day from either a surface or ground water source.

Q1 - I have an irrigation system that works well. What more can I do?

Step back and review your entire operation. Look for improvements that will reduce your water use or ensure that you are using only that amount which is needed.

• Inspect your system when it is operating and make sure there are not any leaks. If any are found, repair them. Check your system frequently.
• If possible, irrigate later in the day or evening, when temperatures are lower and there is less evaporation loss. This may not be an option for all crops as disease could be an issue.
• Avoid irrigating during windy conditions. Not only is water loss due to evaporation much higher, but it is difficult to obtain an even distribution of water, especially for large volume gun systems.
• Use rain gauges to measure how much water is being applied and if it is the intended amount. Consider using enough gauges to determine how evenly you have irrigated.
• Watch your system to ensure that the application rate does not exceed how fast the ground will accept it (infiltration). If it does, you will see runoff. Not only is this a waste of water, but you are also not getting the full benefit of the application.
• If you have a system where the pipes are moved between irrigations, try to allow the pipes to drain back into storage, if possible.

Q2 - I irrigate from a stream, as do my neighbours. If we all irrigate at the same time there may not be enough water. What can I do?

Recognizing the situation is a major step in the right direction.

• Understand and respect the rights of all who have an interest in the water. Try to understand the effect your taking of water may have on others. Make appropriate decisions. Consider organizing with your neighbours to set up a staggered irrigation schedule, so that everyone is not irrigating at the same time.
• Some systems require operating a large pump over a short period of time. Consider the following system, which has less affect on the stream and is easier to manage.
  • Dig a pond near a stream to use as a temporary storage.
  • Pump from the stream into the pond, using a smaller pump over a longer period of time.
  • The major withdrawal for irrigation then takes place from the pond with the larger irrigation pumps. This is a better sharing of the water resource and is easier to manage.
  • Remember, even if you have a Permit to Take Water from the Ministry of the Environment, it does not give you the right to take all the water in a stream.
• Don’t forget that there are many other uses and needs for the water in streams. At no time can you take the entire flow from a stream or block the entire flow. Become familiar with the conditions and your responsibilities as outlined in your Permit to Take Water.

NOTE: Your Permit to Take Water states: "For surface water takings, the taking of water shall be carried out in such a manner that the stream flow is not stopped and is not reduced to a rate that will cause interference to downstream uses of water or with the natural functions of the stream."

Q3 - What else can I do?

If you do not have one, develop an irrigation plan. If you have a plan, review it to make sure it is up to date.

• Inventory how much water you have in storage, or have access to, from streams or water wells.
• Set out a desired irrigation scheduling program. Take into account projected needs of the crop, soil type, evaporation and transpiration, rooting depth, critical periods of growth, etc.
• Review and understand the conditions of your Permit to Take Water. Do not exceed the limits of your permit.
• Follow your irrigation plan and update it as needed.
• Either weekly or daily, review your volume of water in storage or water availability. Determine if your water supply matches your needs.

Q4 - What if I still do not have enough water to irrigate all my crops? 

Part of your irrigation plan should include a contingency or emergency plan outlining what you will do if your water supply does not meet your demands. Some hard decisions may have to be made. Each situation will be different.

• Which crops will suffer more if you cut back on irrigation?
• Which crops are at a critical stage?
• Can you reduce the irrigation rate further?

You will have to set priorities for your particular situation Prepare your emergency plan prior to any emergency. In the heat of the moment it is more difficult to make these very important decisions. It does not make it any easier, but hopefully, you will make better choices. 

Q5  - If I irrigate directly from a water well, what can I do?  

• Operate within your Permit to Take Water conditions.
• Monitor the effect of the pumping on the static water level of any of your other wells or neighbour’s wells, if possible.
• Shortly after pumping, monitor the static water level from the well you are using, to see:
  • how much the water level has been drawn down, and
  • the recovery rate of the well.
    The pump may make this difficult, unless you have special equipment installed or an adjacent monitoring well.
• Consider hiring a hydrogeologist to assess what effect your water withdrawal may have on the ground water and neighbouring wells. Monitoring wells may be needed to document the impact of water withdrawals.

Q6  - I have a trickle irrigation system which is supposed to be very water efficient. Do I need to do anything?

Trickle irrigation systems are very efficient. But many points from the previous questions also apply to trickle systems, especially maintenance, scheduling, monitoring your water supply, developing an emergency plan etc. 

Q7 - I think there should be more water in the stream. I am concerned that someone is using too much water. What can I do? 

• Verify that there should be more water. Check flow levels upstream at road crossings. Lower stream flows could simply be the result of the dry weather.
• If low flow levels are the result of withdrawals by upstream neighbours, consider discussing the situation with them. It may be possible to work out a schedule that will meet everyone’s needs and maintain a flow in the stream.
• Do not get into a confrontational situation with your neighbours. If relations are already tense or suspect, it may be better to get a third party neighbour or commodity representative involved that is respected by all.
• If necessary, contact the Ontario Ministry of the Environment to verify that there are valid Permits to Take Water in place and to find out what options are available to you.

Useful References

The following publications are available from the Ontario Ministry of Agriculture and Food:

Best Management Practices: Field Crops
Best Management Practices: Fish and Wildlife Habitat Management
Best Management Practices: Horticultural Crops
Best Management Practices: Irrigation
Best Management Practices: Water Management
Best Management Practices: Water Wells

Best Management Practices publications can also be ordered from the Ontario Federation of Agriculture.
Attn: Manager BMP
40 Eglinton Ave. E, 5th Floor
Toronto, ON M4P 3B1
Tel. (416) 485-3333
Fax (416) 485-9027
E-Mail: info@ofa.on.ca
Website: www.ofa.on.ca