CLOGGING AND MAINTENANCE OF MICRO IRRIGATION SYSTEMS - Management, Performance, and Applications of Micro Irrigation Systems - page 91

The Fig. 2(top) shows a fi eld with plant stress produced by emitter clogging caused
by manganese oxides at the Texas Agricultural Experiment Station Helms Research
Farm, south of Halfway, Texas. The general condition of a drip system can be easily
evaluated by frequent observation of system pressures and fl ow rates. If emitter plug-
ging occurs, system pressures will increase and fl ows will decrease. Acid injection can
reduce clogging problems so fi elds are irrigated uniformly, as shown in Fig. 2(bottom).
The Fig. 3 indicates the roots that are penetrating the drip-lines.

7.2.3 FLUSHING LINES AND MANIFOLDS
Very fine particles pass through the filters and can clog the emitters. As long as the wa-
ter velocity is high and the water flow is turbulent, these particles remain suspended.
If the water velocity slows or the water becomes less turbulent, these particles may
settle out. This commonly occurs at the distant ends of the lateral lines. If they are
not flushed, the emitters will plug and the line eventually will be filled with sediment
from the downstream end to the upstream end. Systems must be designed so that
mainlines, submains, manifolds and laterals can all be flushed. Mainlines, submains
and manifolds are flushed with a valve installed at the very end of each line. Lines can
be flushed manually or automatically. It is important to flush the lines at least every 2
weeks during the growing season.

FIGURE 2 Plants in this field are drought-stressed because emitters are clogged (Top). Acid