MATHEMATICAL-DESCRIPTION OF WATER HYACINTH (EICHHORNIA-CRASSIPES) MATCOMPACTION

A mathematical model of water hyacinth mat compaction was developed fo r estimating the force required to compact a mat prior to towing. Desc riptions of elements and structure of the model were developed from ph ysical laws and experimental data obtained using square water hyacinth mats of 9 m(2) area. Principal system variables were horizontal veloc ity and displacement of the mat and compaction force in response to co mpaction velocity input. Model predicted and experimental compaction f orce and mat compaction were compared. Compaction force increased with compaction velocity; compaction force primarily opposed drag for velo cities > 0.26 m s(-1) and leaf sliding friction for velocities < 0.15 m s(-1). Percent compaction at the onset of mat instability or ''roll under'' ranged from 15 to 40%; it decreased with increasing plant popu lation and decreasing average plant length. It was not affected by com paction velocity.