▁which ▁pass ▁through ▁their ▁dig est ive ▁tract s . ▁ ▁The ▁composition ▁of ▁the ▁beach ▁depends ▁upon ▁the ▁nature ▁and ▁quantity ▁of ▁sed iments ▁up stream ▁of ▁the ▁beach , ▁and ▁the ▁speed ▁of ▁flow ▁and ▁tur bid ity ▁of ▁water ▁and ▁wind . ▁Sed iments ▁are ▁moved ▁by ▁moving ▁water ▁and ▁wind ▁according ▁to ▁their ▁particle ▁size ▁and ▁state ▁of ▁comp action . ▁Part icles ▁tend ▁to ▁sett le ▁and ▁compact ▁in ▁still ▁water . ▁ ▁Once ▁compact ed , ▁they ▁are ▁more ▁resist ant ▁to ▁er os ion . ▁ ▁Est ab lished ▁veget ation ▁( es pecially ▁species ▁with ▁complex ▁network ▁root ▁systems ) ▁will ▁resist ▁er os ion ▁by ▁slow ing ▁the ▁fluid ▁flow ▁at ▁the ▁surface ▁layer . ▁When ▁affected ▁by ▁moving ▁water ▁or ▁wind , ▁particles ▁that ▁are ▁er oded ▁and ▁held ▁in ▁susp ension ▁will ▁increase ▁the ▁er os ive ▁power ▁of ▁the ▁fluid ▁that ▁holds ▁them ▁by ▁increasing ▁the ▁average ▁density , ▁vis cos ity , ▁and ▁volume ▁of ▁the ▁moving ▁fluid . ▁ ▁Coast lines ▁facing ▁very ▁ener get ic ▁wind ▁and ▁wave ▁systems ▁will ▁tend ▁to ▁hold ▁only ▁large ▁rocks ▁as ▁smaller ▁particles ▁will ▁be ▁held ▁in ▁susp ension ▁in ▁the ▁tur bid ▁water ▁column ▁and ▁carried ▁to ▁cal mer ▁areas ▁by ▁long sh ore ▁curr ents ▁and ▁t ides . ▁Coast lines ▁that ▁are ▁protected ▁from ▁waves ▁and ▁wind s ▁will ▁tend ▁to ▁allow ▁fin er ▁sed iments ▁such ▁as ▁cl ay ▁and ▁mud ▁to ▁precip itate ▁creating ▁mud ▁fl ats