Flow Treatment 



Two plots per flow 

 treatment 



Increased (Decreased or Control) 



Disturbance 



Frequency 



treatments 



Collection 

 Date 



Same as for 1 



Biweekly Monthly Bimonthly Undisturbed 



5 8 



12 3 4 5 6 7 8 



Sample 



Replicates .-, , 



(3 per date) ' " -^ l 2 3 l 2j* I z J 



I 



1 23 



Figure 1 : Experimental desigr^ of the study. The experiment was a three-way, randomized block, 

 incomplete factorial design to evaluate effects of flow regime and disturbance frequency on macrobenthos 

 over time. Flow treatment levels were: increased by weirs and decreased by nets relative to controls with no 

 structure. Disturbance frequency treatment levels were: biweekly = every 2 weeks, monthly = every 4 

 weeks, bimonthly = every 8 weeks, and undisturbed. Collection dates were: 1 = 23 April 1997, 2 = 07 May 

 1997, 3 = 22 May 1997, 4 = 04 June 1997, 5 = 20 June 1997, 6 = 02 July 1997, 7 = 17 July 1997, and 8 = 01 

 August 1997. 



Predominant Water Flow 



a) 



Control 2 



Net 2 



Direction of 



wind and tidal 



flow 



Weir 2 



) ( ^^ 



Control 1 



Weir 1 



/ \ Net 1 



b) 



Figure 2: Flow alteration treatments for a) weir and net structure designs and b) field emplacement. 



Trays of defaunated sediment were randomly placed in hatched center regions. Undisturbed core samples 

 were obtained in the shaded regions. Control plots were defined by corner posts (dotted lines). 



F- 1 6 V Effects ofTemporality. Disturbance Frequency and W''ater Flow 

 on an Upper Estuarine Macroinfauna Community 



