CLOGGING AND MAINTENANCE OF MICRO IRRIGATION SYSTEMS - Management, Performance, and Applications of Micro Irrigation Systems - page 88

decreased approximately 40% and 30%, respectively, during the four seasons, indi-
cating considerable emitter clogging. The three drip-lines with the greatest discharge
rate emitters (0.1.5, 2.3, and 3.5 L/h) only had approximately 7%, 8%, and 13% emit-
ter discharge reductions, respectively. Sewage water clogged 26% more emitters than
groundwater [17] in a study in China. They also found that with pressure compensat-
ing emitters that the clogging distribution occurred randomly along the drip-line, but
the clogging of non

pressure compensating emitters tended to occur at the distal end
of the drip-lines. Clogging of drip emitters can be also affected by the type of emitter
[7, 18].
It has been observed that on

‐

‐ line pressure compensating emitters have better anti ‐

clogging properties than in line emitters are when the drip-line

is punched and the emitters are inserted into the line and the in

‐ line emitters. The on ‐

line emitters are when
the emitters are extruded into the drip-line. It has also been observed that turbulent

‐

‐

fl ow emitters have better anti fl ow emitters [7, 17,

18]. Most of the reported clogging studies have been conducted in controlled fi eld
experiments with duration of less than 4 years. More studies, which document the
performance of older SDI systems that are still currently operational, are needed. It is
also important to document how these systems have been affected by the source water
quality, what management and maintenance practices have been adopted, and whether
the longevity of operation has affected system performance and irrigation uniformity.
Considering the large investment needed for SDI, it is vital to extend their lifetime
with proper design, management, and maintenance practices.
This chapter describes and provides ideas on how to conduct preventive mainte-
nance, evaluate a drip irrigation system, inject chlorine and sulfuric acid, and provides
some other considerations for maintaining these irrigation systems.

‐ clogging properties than laminar ‐

7.2 PREVENTIVE MAINTENANCE
A permanent system, properly designed and maintained, should last more than 20
years. A maintenance program includes cleaning the filters, flushing the lines, adding
chlorine, and injecting acids. These preventive measures will reduce the need for ma-
jor repairs and extend the life of the system.
The purpose of preventive maintenance is to keep the emitters from plugging.
Emitters can be plugged by suspended solids, magnesium and calcium precipitation,
manganese-iron oxides and sulfi des, algae, bacteria and plant roots. Each SDI system
should contain a fl ow meter and at least two pressure gauges-one gauge before the
fi lters and another after the fi lters. Flow meters and pressure gauges, which should be
inspected daily, indicate whether the system is working properly. A low pressure read-
ing on a pressure gauge indicates a leak in the system (such as a leaking component or
broken pipe). A difference in pressure between the fi lters may imply that the system is
not being back fl ushed properly and that the fi lters need to be cleaned. In larger sys-
tems, pressure gauges should be installed in each fi eld block or zone.
Water quality determines the relative risk of emitter plugging and other problems;
therefore, the properties of the water should be taken into account in the system main-
tenance program. Examples of water quality parameters and their effect on emitter