In temperate regions, light and/or temperature variations may modify the effects of the pulse, and anthropogenic influences on the flood pulse or floodplain frequently limit production.
Figure 1. Missouri River Basin (from USACE, 2001)
Another important question: Were the least tern and piping plover historically numerous on the Missouri River, especially above Platte River? It was assumed in the biological opinion, without quantitative data and without substantial observations, that the least tern and piping plover were in the past much more numerous on the Missouri River in this reach. A review of historic information concerning the least tern and piping plover indicates that typically the June rise flooded the sandbars from June into August (Beacom, 2003). (Traditionally the rise, which typically starts in May and extends through July, is termed the June rise. A more accurate description would be the June-July rise. A purpose of this study is to evaluate the natural hydrograph at Sioux City, Iowa, to determine if the