Review of the Trinity River Restoration Program Following Phase 1, with Emphasis on the Program's Channel Rehabilitation Strategy

Details of the Phase 1 channel rehabilitation activities are given in Appendices C and G and are summarized here. During Phase 1 (2005-2010), 15 rehabilitation projects were completed along the course of the restoration reach (Table 1, Figure 1). Projects were initially focused on removing riparian berms that had encroached on the river following dam closure, lowering floodplains to match the post-ROD flow regime, and creating point bars that would promote a dynamic river. The conceptual model for these activities was that if restraining features were removed, fluvial processes would take over, creating a more dynamic and complex river that, in turn, would offer more productive habitat for fish and wildlife (USFWS AND HVT 1999; USDOI 2000). It was also recognized that the river could not be restored to pre-dam conditions
and that it would have to be scaled down to the post-ROD flow regime (USFWS AND HVT 1999). However, the initial rehabilitation projects produced little immediate dynamic geomorphic response. Consequently, the degree of mechanical intervention and complexity of projects increased over time. The intent of these more intensive projects was, in part, to create immediate habitat and to construct large-scale channel features that would interact with flood flows and drive more rapid channel changes. This change in design strategy was based on lessons learned and, in general terms, is a type of adaptive management, but represents a shift from the foundational notion that a more dynamic river could be created with minimal bank reconstruction (USFWS AND HVT 1999; HVT et al. 2011) .