Upper Black Butte Swamp Restoration

Upper Black Butte Swamp is located on the Sisters Ranger District, southwest of Black Butte. It is a 34- acre wetland within a larger complex of wetlands and surrounding aspen stands. Though named a “swamp”, it is actually a unique type of groundwater dependent wetland called a fen. Indian Ford Creek originates nearby at Paulina Springs and flows year- round through Upper Black Butte Swamp.

The Forest Service hopes to restore the shallow water table and native wetland vegetation of Upper Black Butte Swamp by filling in existing stream channels, replanting native plants, thinning conifers around aspen stands and managing invasive weeds.

As groundwater dominated ecosystems, fens are not typically characterized by individual stream channels bisecting them as currently found with Indian Ford Creek bisecting Upper Black Butte Swamp. Recent monitoring suggests that the current condition of the incised stream is preventing shallow groundwater from flowing into a large portion of the fen, leading to dry soil and water table decline especially in the western half of the fen. While sedges normally thrive in fens, the water table decline has likely contributed to many of the sedges in the upper (western) end dying off and peat beginning to decompose because it is now exposed to oxygen. Invasive reed canary grass has also established itself in part of the degraded fen pushing out native vegetation.

Restoring the groundwater levels in Upper Black Butte Swamp to a shallow state will rehabilitate this unique fen, improving special habitat for native wetland plants and a host of wildlife species. Raising the water table closer to the ground surface will help retain peat, support native sedges and willows, as well as reduce wildfire risk in the fen and in adjacent private lands. Simple Document Template (two column with photos)

In its current condition, with up to 3.5 feet of dry organic peat as highly combustible wildfire fuel, if a fire were to ignite or spread into the dried fen, it could burn for months and be difficult to fully suppress. A restored wetland is both an ecological benefit and reduces wildfire fuels.

What restoration actions are proposed for Upper Black Butte Swamp?

• Remove Invasive Weeds and Restore Groundwater Flow: Equipment would be used to excavate a small area (0.25-1.0 acre) at the upper (northwest) end of the swamp and remove clumps of invasive reed canary grass. This shallow sump will serve as a hydrologic transition zone, where surface water in Indian Ford Creek can be spread laterally to infiltrate into the shallow groundwater system.
• Fill the Incised Stream Channels: The perennial Indian Ford Creek channel (~2,800 ft) and the primary intermittent side channel on the east side of the swamp would be filled with approximately 2,000 cubic yards of material. Material would be sourced from on site and from the nearby Black Butte pit. Over time small, braided channels and rivulets would be expected to form naturally. Where a small amount of surface water presently flows out of the swamp into a collapsed lava tube on the west edge of the swamp, the outlet may be plugged with earthen material (<50 cubic yards).
• Aspen Stand Improvement: Small to medium sized conifers would be cut within the aspen stands surrounding Upper Black Butte Swamp. The trees may be removed, used for stabilizing the wetland restoration, or left on site scattered or piled and burned. Cutting conifers allows more water availability and sunlight to stimulate the aspen suckers to sprout.
• Gravel Placement in Indian Ford Creek: To enhance redband trout spawning habitat, gravel would be placed in Indian Ford Creek downstream of Black Butte Swamp and upstream of Hwy 20. Several locations (12-20 sites) have been identified along the creek. These sites have low densities of silt and velocities needed to maintain gravel with minimal silt deposition. Gravel would be brought in with a power wheelbarrow using existing roads and trails and transported to the stream with Forest Service employees, volunteers, or youth crews.
• Water Quality and Quantity: With a primary objective to restore fen hydrology, changes to flows and water quality would be anticipated during and following the project implementation. Project review and design will consider effects to stream temperature and downstream flows. Based on scientific research of similar wetland restoration projects and recent monitoring of the Lower Black Butte Swamp restoration, in the long-term, we anticipate a delay in timing of seasonal low flows in Indian Ford Creek downstream of the swamp complex, but no reductions in base flows. During and immediately post project implementation, however, we expect that downstream flows to decrease as groundwater recharges the peat wetland.

What are the anticipated effects of restoration?

The restoration is expected to have long term ecological benefits and reduce wildfire risk. However, short-term impacts in the wetland and associated stream channels can be expected. The restoration would alter the wetland by moving away from a deep stream channel with deep water habitat and instead go to a groundwater based, fen system with more surface aquatic habitat. Project design will include careful consideration of these impacts.

Aquatic and Wildlife Species: Indian Ford Creek is currently used by native aquatic species such as the
redband trout, western pearlshell mussels and signal crayfish. These aquatic species would be relocated to other parts of the creek prior to channel filling. Filling in the Indian Ford Creek channel through the swamp area may affect aquatic species movement and use for a period of time. Shallow, braided channels and rivulets are expected to form within a year or less after restoration to provide aquatic species passage.