The area of ponded water, which includes those low-lying areas which 

 accumulate water but are not effective in the conveyance of flow, was in- 

 creased at roughly half of the study sites. This ponding indicated that 

 the site was not smoothed during restoration, was excavated too deeply, 

 or was not properly drained. Table 7 lists the relative effect of this 

 parameter at the 25 study sites. The impact of the ponding to the hydraulics 

 of the systems was not great. However, it was a concern to aesthetics and 

 fish entrapment evaluations. 



Channel Slope. Channel slope changes took the form of an overall in- 

 crease in slope or a local redistribution of slope. An overal I increase 

 in slope was commonly due to the formation of a meander cutoff. A redistri- 

 bution of slope without changing the overall slope occurred when the slope 

 was increased leading into the gravel removal area and decreased through 

 the gravel removal area. Table 7 indicates those sites which had slope 

 changes. 



Study sites exhibiting an overal I increase in slope due to gravel 

 removal were generally in small, nonbraided river systems that were exca- 

 vated by scraping techniques. The location of gravel removal was an impor- 

 tant factor affecting the overall slope of the system. Sites such as upper 

 Washington Creek, Penny River, Skeetercake Creek, and lower Middle Fork 

 Koyukuk R i ver-Upstream, that were excavated on the inside of bends, mean- 

 ders, and islands most significantly affected the overall slope of the river 

 system. This influence was expected because significant increases in slope 

 are most likely to result from the development of a meander cutoff (reducing 

 channel length and increasing slope). 



The Penny River gravel removal operation caused a significant increase 

 in overall slope (Figure 33). The photograph of the site after the gravel 

 was removed shows that the main channel flows in a relatively straight 

 course along the inside of two broad meanders that were cut off in the 

 excavation process. The channel length was reduced by a factor of two in the 

 process, equivalent to doubling the overall slope through that reach. 

 Doubling the slope has the effect of increasing the mean velocity by roughly 

 40 percent. 



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