Figure 10>~Carp Creek weir at low water stage. July 1, 19U7. 



sheet piling, driven into the softer bank} they were also secured 

 at the trap, on each side of its entrance. The greatest problem 

 was anchoring the wings and trap to the stream bottom in order 

 that no undercutting would take place. It was impossible to drive 

 sheet piling for this purpose since beneath a shallow layer of 

 gravel the stream bed was composed of very hard clay. To circum- 

 vent this, a trench two feet wide and six inches deep was dug 

 astraddle the line of fence-post uprights, A strip of hardware 

 cloth the length of the wing and 2k inches wide was nailed to a 

 2 inch by k inch wood sill of equal length and placed, hardware 

 cloth down, in the trench, with the sill braced against the up- 

 stream side of the uprights. The bottom edge of the lower gravel 

 screen rested on this sill. Spacers of 1 inch by 6 inch wood 

 planking were added on the downstream side, between the uprights, 

 to prevent any buckling of the gravel screen backing (see detail. 

 Figure 7), After the hardware cloth had been added, the trench 

 was filled with heavy gravel and sand, A dressing of larger 

 rocks was placed on the downstream side to prevent scouring. 



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