EMERSED AQUATIC WEEDS 



Many plant pests that root in the aquatic soil and send stems and 

 leaves above the water surface are grouped in this category and are well 

 known to irrigation operators. Some of the species in this group are 

 the first to invade newly inundated lands, especially when the features 

 are intermittently wet or where the water is normally shallow. 

 Backwater areas of reservoirs and drainage canals are especially 

 troubled by these weeds. The cattail and bulrush species, which are 

 illustrated, typify these plants. A number of additional species are 

 known to infest such environments, but vary locally and are too 

 numerous for inclusion in this booklet. 



Emersed weeds are especially troublesome to irrigation systems in 

 that they spread rapidly to choke drainage channels, increase silt 

 deposition, interfere with designed operation and maintenance 

 procedures, and waste tremendous quantities of water through natural 

 life processes of transpiration. 



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