Ze 
PERCENT OF STREAMBED AFFECTED 
undisturbed 
1950-51 1951-52 1952—53 1953—54 
YEAR 
Fig. 19-- Relationship between cut and fill greater 
than |.2 inches, and undisturbed sections. 
HARRIS RIVER —INDIAN CREEK INTERTIDAL ZONE 
The period has been one of net deposition with a fill of 556 cubic 
yards and a cut of only 61 cubic yards in the 200-foot section. This 
accumulation is net and represents the minimum change which took place 
during the period. A greater gross volume change may have taken place 
as these gravels are continuously being shifted from one position to 
another. 
The analysis has shown quite decisively that the intertidal zone at 
the confluence of Harris River-Indian Creek is unstable under natural ~» 
conditions and subject to considerable movement of streambed material. 
The alluvial meterial in this zone is easily molded and reworked. The 
intertidal zone may be more susceptible to sediment deposition than 
to erosion because tidal action in this reach produces a fluctuating 
reservoir. Deposition is induced during periods of slack water because 
the incoming tide reduces the particle carrying capacity of the fresh- 
water stream. Deposition of material is also induced by the chemical 
action of flocculation and precipitation (14). The greatest amount of 
shifting usually occurs during periods of high stream runoff, parti- 
cularly during the fall months when eggs are deposited in the gravel. 
2 40n= 
