Eastside Type N Riparian Effectiveness Project

ENREP - FHS ExtensionFebruary 5, 2015

Why the FHS Extension

2. Modify the westside Type N study designs for the eastside and proceed with the study in basins with spatially-continuous Np streams.

The variability in hydrologic condition and extent of dry Np channels led to a two-part recommendation from the TWIG for ENREP study design development.

November 2013: Policy approved this recommendation, and expressed an interest in seeing a single study design applied to all eastside basins, if feasible.

1. Extend FHS to learn more about the distribution and persistence of dry reaches.

FHS Extension products

Variation in hydrologic condition

Isolated Channels

• Isolated channels were identified by the lack of a channel connection to the downstream network.• These breaks in channel connectivity occurred where an

upstream channel ended in a section of unchanneled hillslope.

• Lack of channel connectivity interrupted surface water transport of water, material, biota, and thermal energy.

• Some basins contained no isolated Np. In some others there was no channel at the outlet, so the entire channel network was isolated.

• Np channels that were both dry and isolated comprised 2%-4% of the total channel network.

Association with potential Np buffer zones

11% (0.5%) Isolated: 3% (0.14%)

29% (1.3%) Isolated: 7% (0.31%)

Key findingsIn the drier FHS basins (>500 feet of dry Np):

• 35% of the Np channel length was dry in late summer (FHS: 21% was dry).

• 12% of the Np channel length was dry in late spring.

• 70-75% of dry Np channels have a channel connection to downstream waters beyond the basin outlet (FHS: 77%).• Important for the delivery of material and energy to the fish-

bearing network.

• Stream hydrologic condition is generally stable within seasonal drying patterns. Therefore, a single ENREP study design is feasible.

Next steps• Prepare the FHS Extension report.

• In close cooperation with landowners, develop a single study design to test the effectiveness of current FP Type N rules.• Determine study basin characteristics

• Size, hydrologic condition, distribution, etc.

• Determine type and scale of harvest• Identify at least 20 study basins• Number of treatment types and overall success

depend on availability of study basins.

• Collect pre-harvest data in spring 2016 – 2017.

• Apply the designed harvest in fall 2018 – 2019.