Types of Log Jams

Step Wise Guide

Riparian Management - Types of Log Jams

· What types of log jams can I expect depending on tree size versus channel size?

NetMap contains a tool for estimating the types of wood accumulation in streams. Four wood accumulation types are defined in NetMap based on field measurements: 1) individual spanning logs, 2) spanning and partial stream-spanning jams (30 – 70% of the channel is spanned), 3) scattered accumulations on lateral bars, and 4) no wood accumulation (too high energy streams) (Figure 1).

The model objective is to minimize complexity in order to examine how a few factors (drainage area and slope [stream power], riparian tree height [e.g., log size], and channel width) impose constraints on spatial patterns of different wood accumulation types at the scales of watersheds. For instance, large, channel-spanning logs in small streams tend to stay where they fall. If the channel has sufficient power to transport wood, channel-spanning logs can form. Larger and more powerful channels will favor the formation of partial jams, scattered bar accumulation, or no accumulations at all.

Step 1: Go to NetMap's tool for evaluating different type of log jam potential.

aquatic habitat tools.