Improve irrigation system now to beat next drought

Golf Course News, Nov 2002 by Davis, David D

Editorial Focus: Irrigation & Pump stations

While rainfall at the right time solves many irrigation problems, recent weather patterns have brought drought to large portions of the country.

Under drought conditions, a system designed and maintained to handle an and climate might not require too many tweaks to improve efficiency. A system designed to supplement rainfall, on the other hand, may require substantial tweaks and/or upgrades, just to survive a short drought. A prolonged or multiple-year drought could lead to severe turf damage and perhaps complete replacement of the irrigation system.

Even if your golf course and irrigation systems will not face droughts, you will face years of reduced rainfall, reduced humidity and increased temperatures, all of which increases irrigation requirements and stresses on your total system.

In either case, there are several steps you can take to improve your irrigation system. First, actually evaluate your system.

ITEMS TO TRACK AND EVALUATE INCLUDE:

* Power and water consumption - increases over a period of time indicate system wear and probably loss of efficient coverage.

* Sprinkler repair costs - increases year after year indicate excessive wear with definite loss of operating efficiencies. This includes power and control wire failure, broken sprinklers and worn nozzles.

* The number of extra people it takes to hand-water hot spots or work on correcting coverage problems increases each season, regardless of weather conditions.

* Increasing frequency of pump station repair, including accessory equipment, generally indicates loss of pressure and flow.

* Length of time to complete irrigation programs and schedules - increases in schedule length can indicate many problems, including pump and sprinkler wear, inadequate mainline sizes and reduced efficiencies of control systems.

IMMEDIATE ACTIONS COURSES CAN TAKE INCLUDE:

* Audit critical areas of the golf course for coverage efficiencies. Check sprinkler spacing, flow and nozzle pressure.

* Develop a preventive maintenance program to meet your normal irrigation needs as well as drought conditions. This should include nozzle replacement to match coverage requirements and a pump station tune-up, including motors, pumps, filters, etc. In addition, tune-up mainline and lateral isolation valves, make sure all valves are fully open, check controller programs and schedules for balanced flow and pressure relationship.

* Develop a short-term droughtmanagement plan. Consider what you have to do to survive a drought. This should include repair of system components and identification of supplemental water sources. The plan should also include identification of turf and ornamental areas, which can survive on reduced or "deficit" irrigation.

When short-term actions do not increase irrigation efficiency, renovation or outright replacement of irrigation system should be planned.

RENOVATION AND/OR REPLACEMENT PLANS SHOULD INCLUDE:

* Use of valve-in-head sprinklers having low scheduling coefficients and high distribution uniformity coefficients.

* A weather station to develop real-time site data to facilitate sprinkler programming and scheduling

* A state-of-the-art central control system and field controllers. Central control should be capable of monitoring pumps, filters, weather station, flow meters, etc.

* Use of properly sized mainlines to minimize excessive pressure losses and energy costs.

* High-efficiency pump stations including high-efficiency motors, pumps, filters, valves and piping to reduce cost of operation.

* Use of high-efficiency flow metering equipment on pump station and/or water source point of connection to accurately measure quantities of water delivered.

* Develop a long-term droughtmanagement plan which incorporates area separations by feature, specific site location, plant material, irrigation requirement or environmental exposure to facilitate various levels of reduced irrigation.

* Create GPS record plans to provide a more accurate map of equipment, mow lines and features (see related story on page 1).

These steps taken to improve system efficiency can reduce operating costs and improve playability even during droughts. An efficient irrigation system also reduces the stress on superintendents.

David D. Davis is the president of the irrigation consulting firm David D. Davis fy Associates in Arrowhead Highlands, Calif.