However, islands constructed in other pools beginning in 1990 have not yet resulted in substantial land emergence around built areas. Observation of large wood involved in early stages of Gull Island growth is in concordance with research on the important role of wood in island growth in braided rivers throughout the world (Gurnell et al., 2005). This suggests that, in suitably shallow water, introduction of large wood, either during floods or as a restorative act, may be an alternative to rockfill as a method of seeding island growth. Based on the above considerations, the combination of available
sediment, flow obstacles created by submerged PCI-32765 cell line rock structures, and a wide secondary channel in a constricted river belt has enabled unassisted island regeneration in LP6. Relative to other pools in this reach of the UMRS, the most unique
characteristic of Pool 6 appears to be the anomalously narrow character of the lower pool with its wide secondary channel. This suggests that in areas with adequate sediment supplies and where structures can serve as nuclei for island growth, the most important strategy for promoting island emergence may be reducing wave-induced resuspension of sediment. This has been a goal of efforts undertaken by the USACE, and provides a hopeful sign that restoration efforts in the UMRS will be successful in creating conditions for island persistence and growth. Over 150 years of intense river management has radically NVP-BGJ398 altered morphodynamics in the UMRS, which was once island braided with extensive floodplain backwaters. Today, erosion and island loss are dominant trends within connected channel areas, and restoration and island creation efforts are underway. However, in Pool 6 of the UMRS, deposition over the last 40 years has created a river morphology that mimics the pre-management pattern, without restoration efforts. Between 1895 and 1931, constructed wing and closing dikes facilitated rapid land emergence. Raised water levels that followed construction of the Lock and Dam system in 1936 led P-type ATPase to loss of emergent land. However, since 1975, land has emerged
throughout the pool, but particularly in the lower pool where several new islands emerged. In this area, 0.37 km2 of islands emerged, increasing land area by 88% relative to 1975. In the lower pool, sediments have aggraded 2.2 m in 111 years, with the Lock and Dam having only a slight effect on aggradation rate. The locations of wing and closing dikes in a wide secondary channel within an overall constricted river width have contributed to island emergence and growth in Lower Pool 6. These conditions are fairly unique within the surrounding pools in the UMRS, which have experienced island loss with no natural recovery. Reducing wave action through constructed structures to disrupt wind fetch and seeding islands with rock structures or large wood are strategies that may contribute to natural land emergence in open water areas of the UMRS.