Natural logjams directly affect fluvial processes such as flow paths, flow conveyance and water levels, channel morphology and planform, sediment transport and deposition, pool formation, and riparian vegetation (Collins et al., 2012).

WHAT IS AN ENGINEERED LOG JAM? “An ELJ is a human designed and constructed log structure that emulates the functions of historic naturally-occurring logjams to restore riverine geomorphic, hydraulic, and sediment transport processes” (Abbe et al 2018)

Jams can be assembled at the inlet of pre-existing or constructed side channels to regulate the amount of flood flow entering the side channel (see Large Wood and Log Jams Figure 4). This can slow or delay imminent channel avulsion while allowing riparian vegetation to mature.

Large wood and log jams are a critical component of salmon habitat, forming pools, providing complex hiding cover, stabilizing river channels and banks, sorting gravel, and connecting floodplain channels.

The overall river restoration design, led by Wolf Water Resources, involved reconnecting a 2,200-foot side channel and installing two 600-piece engineered log jams to engage the side channel when mainstem flows exceed 800 cfs.

Aug 1, 2024 · In this paper, we present a conceptual model that relates valley setting and landscape history of forested, mountain streams to spatiotemporal patterns of sediment storage and transport via the formation and decay processes of logjams.

Engineered Log Jams for Geomorphic Processes and Habitat Complexity in Low Gradient Alluvial Valleys

ELWd®log jam structures make it practical to add complex habitat and hydraulic structures to small streams. Log jams store fine organic debris, trigger scour pool formation and provide important hydraulic routing benefits.

Engineered Log Jams: Recent Developments in Their Design and Placement, with examples from the Pacific Northwest, U.S.A

There are different types of constructed log jams (fluvial-geomorphic wood complexes) as well as some that occur naturally at sharp bends in a stream channel, usually from high water level (flood) events or stream avulsions occurring upstream.