Peekaboo Falls Fish Passage Discussion

Overview

Peekaboo Falls is a natural waterfall that currently acts as a total barrier to upstream passage of bull trout in Box Canyon Creek. It is located 1.6 miles above the confluence of the creek and Kachess Reservoir (47.376066, -121.258384). Bull Trout in Box Canyon Creek are a genetically distinct population (Small et al 2009) that migrate between habitat in Box Canyon Creek and Kachess Lake. Limited stream capacity for spawning and rearing has been identified as a primary limiting factor for the population. Spawning and juvenile rearing is currently limited to 1.6 miles of Box Canyon Creek below Peekaboo Falls. There is 150% more rearing habitat above the falls (2.5 mi/4 km additional) relative to below the falls (1.6 mi/2.6 km) and there is more low-gradient habitat for rearing above the falls.  Bull Trout hatched here would be less likely to be flushed down to the limited rearing habitat below the “one-way” falls (0.6 mi/1 km) known as Big Pool Falls (see below) or to the reservoir environment where they would be easy prey for larger fish. The habitat in the lower reach of Box Canyon Creek was significantly reduced in 1912 when Kachess Dam was built, seasonally inundating what would have once been complex fluvial habitat in old growth forest in the lowest 0.4 miles of the creek. This 0.4 miles is now seasonally inundated by the reservoir, causing the reach to have little to no vegetation and unstable channels that shift from year to year. It provides no significant rearing habitat for juvenile bull trout.

Box Canyon Creek showing the current Bull Trout distribution and significant water falls within it.

Peekaboo Falls is almost passable (adult fish have been observed jumping up the falls, but not making it all the way over) and there is some evidence that bull trout occupied the stream upstream of the Falls in the recent past. The Yakima Bull Trout Working Group has long discussed whether providing fish passage at the falls and/or transporting fish past the Falls would be an effective strategy to expand productive rearing and spawning habitat for the Box Canyon Bull Trout population. This page has been set up as a record of these discussions and sources of information.

Link to Scott memo- Box Canyon reintroduction Fact sheet on desktop

Description of Peekaboo Falls

Peekaboo Falls at 5 cfs, as measured 1.5 miles downstream near the Kachess Campground.

Peekaboo Falls is a natural barrier on Box Canyon Creek formed by bedrock and boulders. It is 5.5 meters (18 ft) total height over a 13-meter lateral distance; however, the first 2 meters (6 ft) is the steepest and the likely cause of lack of fish passage.

Habitat Conditions upstream of Peekaboo Falls

The USFS did level stream surveys in Box Canyon Creek in 1989, 1995, and 2002.  They used Hankin and Reeves methodology as described in the 1989 Stream Inventory Handbook.

In 1989, the stream was surveyed from the mouth to a point just upstream of the Rachel Lake trailhead (4.2 miles reported, but about 4.6 miles per calculations in 2017).  Above Peekaboo Falls was considered well- to moderately-shaded and had heavy recreational use.  The creek met forest standards for fine sediment, and did not meet forest standards for temperature and large wood.  Forest standards for pools were met in the lower part of the reach above Peekaboo, but not met in the reach above the first culvert.

In 1995, the stream was surveyed from the mouth to the outlet of Rachel Lake (7.7 miles).  The area above Peekaboo Falls again was well- to moderately- shaded, had heavy recreational use, and did not meet standards for wood. This time it did not meet forest standards for pools in the lower part nor the reach above the first culvert.

In 2002, the stream was surveyed from the mouth to a point just upstream of the Rachel Lake trailhead (4.09 miles reported, but about 4.6 miles per calculations in 2017).  This survey documented human waste on the banks of the stream.  Data was not reportedly similarly as in the previous two surveys, so comparisons are not made.

August mean water temperatures near the mouth of Box Canyon Creek (RM 0.2) and at 5M Falls (RM 4.5), 2.9 miles above Peekaboo Falls.

In 2016, the stream was surveyed from the mouth to Peekaboo Falls, and in 2017 it was surveyed from Peekaboo Falls to a point just upstream of the Rachel Lake trailhead.  Above Peekaboo Falls, while wood load met some wood criteria for several different criteria for properly functioning streams in the first 1800 meters, most criteria in this reach were not met, and none of the wood criteria were met for the upper 1040 meters.  Pool criteria were not met by several different standards for properly functioning streams throughout the creek, though pool frequency and quality did improve in the upper 500 meters.

As noted in the 1989 survey summary, stream temperature presumably measured near the Kachess campground did meet forest standards in 1989, but did not in 1990.  In 2016 a staff gage with pressure transducer that included temperature recording was installed above the Kachess campground, and then in 2020 a temperature probe was installed just below 5M falls, a natural barrier at river mile 4.5 that is a 5-meter vertical falls. Data comparison between the lower temperature probe where Bull Trout spawn and rear currently and the upper temperature probe that is not regularly used for spawning and rearing shows that temperatures are 2 to 3 degrees C cooler at 5M falls. Considering that the NorWest climate model predicts that August mean temperatures below Peekaboo Falls will be 14 to 16 degrees C, enhancing Bull Trout access above Peekaboo Falls may be necessary to allow them to continue exist in Box Canyon Creek.

There is another waterfall just 1/4 mile above Peekaboo Falls that is anecdotally named "Bomber Falls", which appear less of a passage barrier than Peekaboo Falls. Still, it would need to be assessed for passage if efforts were made to make Peekaboo Falls passable by Bull Trout to ensure as much habitat is opened up to them as possible. There is also a partial barrier at RM 0.6 known as "Big Pool Falls". At low flows this is known to be a barrier to all fish, but when adult Bull Trout are migrating upstream in the early summer at the tail end of the spring melt or after fall rains when flows are higher, these falls are known to be passable due to the fairly consistent presence of Bull Trout adults and redds observed above the falls during redd surveys. However, in recent years fall rains seem to be arriving later and we are seeing more redds being created in the lower 0.6 miles of the stream than in the past. Thus, Big Pool Falls needs to be assessed for future Bull Trout passage improvements also.

Fish usage upstream of Peekaboo Falls

A fish survey on 8/8/1994 by Plum Creek above Peekaboo Falls found bull trout between 0 and 3” and 3 to 6” over five 100-meter reaches between just below Bomber Falls and up to the 100 meters above the second culvert.  Presumably the presence of the 0 to 3” size indicate successful spawning above Peekaboo Falls in 1993 since that size class is not likely to be able pass Peekaboo Falls from downstream.

A nighttime snorkel survey in 100 meters just above peekaboo falls by the USFS in 2000 found mostly cutthroat and sculpin followed by tailed frogs, and a rainbow trout and a rainbow x cutthroat hybrid.

Nighttime snorkel surveys by the WDFW in 2017 found cutthroat trout and sculpin species only in four separate reaches totaling 2,179 meters between Bomber Falls and 5M Falls. Cutthroat trout densities were very high relative to other Bull Trout streams surveyed similarly.

The 1995 stream survey noted that the presence of bull trout above peekaboo falls was likely made possible by a debris jam below those falls that raised the water level below the falls. Passage at these falls has likely been intermittent throughout history as large woody material and large substrate moves through the system.

Options for providing access to Habitat Above Peekaboo Falls

Describe work to date to assess the falls- surveys, Bruce concepts, etc Interfluv assessment

Modification of the Falls

Initial discussion focused on the idea that modifications could be made to the falls to make them more passable, including the construction of cement walls, excavation of portions of the bedrock, and use of large wood at the downstream outlet of the pool below the falls to raise the base pool elevation. Bruce Heiner, Environmental Engineer in the WDFW Habitat program with decades of experience on fish passage projects, did site visits at Peekaboo Falls and Bomber Falls in Summer 2021. While he did not produce documentation of his ideas, Scott Kline discussed the project with him and recalls Heiner coming up with four concepts for fish passage at Peekaboo Falls. 1) temporary installation of a denil or Alaska steep pass ladder during the upstream migration season of spawners, approximately June 1 to October 15. This would require permanent installation of attachment points for easier installation and removal, but would allow the ladder to be designed for a narrow range of lower flows and avoid being damaged by high flows. 2) Permanent installation of a pool and weir structure that approaches the falls on river right, against the bedrock outcrop. This would provide year-round volitional passage but would permanently change the character of the falls, much like the structure at Salmon Falls on the Little Naches River. 3) Permanent installation of a ladder and conduit that detours fish from the Peekaboo Falls pool and to the northwest where there is a natural depression around the bedrock outcrop, along the Forest Road 4930, and return them to a section of stream that comes very close to the road about 150 meters upstream of Peekaboo Falls. 4) Boulder and tree placement below the falls to backwater the falls enough to make it passable by adult Bull Trout. Careful engineering would be required to ensure it doesn't create a barrier to upstream migration and may be susceptible to damage from high flows.

Pollyanna Lind, an engineer with Inter-Fluve, (an engineering consulting firm) visited the site and documented her ideas in a write-up in in October 2021. She proposed four options. 1) Boulder sill just below Peekaboo Falls. This would create a backwater effect on the falls to make the falls passable by Adult Bull Trout. 2) Modify bedrock at falls. This would involve cutting or blasting a series of chutes and pools in the existing falls. "This would require that the top of the falls be moved upstream to accommodate the required modifications in gradient and form." 3) a seasonal fish ladder (Alaska steep pass or Denil), similar to Heiner's idea discussed above. 4) Trap and haul Bull Trout from the pool to points upstream (see further discussion of this option below).

Fish Transport

Before investing the money in developing a fish passage project in Box Canyon Creek there was a proposal to trap and haul adult Bull Trout above Peekaboo and monitor their success at spawning and recruitment of their offspring into the system. Given counts of adults in the pool below Peekaboo Falls in the past it was thought that those fish would be the ones we could move given their apparent desire to move further upstream and easy access for capture. However, it was determined that there was too much genetic and abundance risk associated with choosing which fish to move upstream. The concern is that we may create a genetic issue if we moved fish too related to each other and that we may reduce spawning success for the population that remained below Peekaboo Falls. There just are not enough fish to work with. Since this trap and haul idea was proposed we have monitored for adult Bull Trout presence in the pool at Peekaboo Falls and found that there are fewer adults holding in that pool than what has been observed in the past.

Another discussion to monitor the viability of the passage project involved capturing fry at the mouth of Box Canyon creek and transporting them (immediately or possibly after rearing) above the falls. Other studies have shown that fry that enter a lake environment do not return to the stream as adults, presumably because the fry become prey to the larger predators there. Based on other studies and observations of the maximum-aged Bull Trout that we have observed in Box Canyon Creek, most fish leave the stream environment by age 3 (at a size where they are more likely to avoid predators). So the pros of this project would be that the population wouldn't be impacted by the loss of fry and the fish used to test survival above the falls would be of the same genetic character as the current population. The major con of the project is that capture of fry in the reservoir environment is difficult and we are unsure of how many fry would be captured.

Capturing juveniles from Box Canyon Creek and transporting them upstream above the falls has been considered but is very labor intensive. Also, additional modeling would need to be done to determine the impact of taking those fish out of the current population.

Using Kachess River fish captured during fish rescue efforts in the summer can also be considered for transport above the falls to test survival in that environment. We have documentation that some adults observed in Box Canyon Creek were from the Kachess River or at least their parents were, so there already is some evidence of gene flow between the two systems. Still, the spawn timing difference between the two populations is different enough to raise concerns that the Kachess fish may not be genetically appropriate for Box Canyon.

Questions that have been raised:

Have bull trout been present above Peekaboo Falls in the past?

Yes, they have. Surveys in 1994 documented their presence. Notes about the debris configuration below Peekaboo Falls by WDFW biologists and USFS biologists and observations of fish nearly succeeding in ascending the falls together identify a reasonable deduction that woody debris can create a backwater effect that reduces the jump fish are required to make to pass the falls. Another possibility explaining Bull Trout presence above Peekaboo Falls is that there are anecdotes of fisherman at Peekaboo Falls catching Bull Trout and moving them upstream. Without documentation of how many fish were transported or for how many years, this is not considered a long-term or significant explanation of Bull Trout presence above Peekaboo Falls.

Are there any unique characteristics of the habitat upstream of the falls that might be impacted?

Ref cutthroat studies but note sympatry in past and in other parts of the basin

There have been some concerns that the cutthroat above and below Peekaboo Falls may be distinct from each other due to extended isolation. However, there has likely always been upstream to downstream migration of westslope cutthroat that allows for gene flow to the population below Peekaboo Falls, thereby making these two populations sufficiently related, if not identical, to dismiss any concerns about them interacting further. Besides a genetic distinctness, other concerns about potential mixing of populations above and below the falls involves the transmittal of diseases from downstream to upstream. Tissue samples of cutthroat from below and above Peekaboo Falls were taken in 2020 to determine if there were distinct health issues, parasites, or diseases in either population that may caution us against providing upstream fish passage over the falls. Bacterial Kidney Disease and digenetic trematodes were found in westslope cutthroat both above and below Peekaboo Falls.  Thus, the fish assemblage above Peekaboo Falls will not be uniquely exposed for the first time to these pathogens if bull trout and possibly cutthroat trout from below Peekaboo Falls were reintroduced above the falls.  Hexamita, the flagellated protozoan parasite, which can cause Hexamitosis, was found only below Peekaboo Falls in the cutthroat samples.  Cutthroat trout that had Hexamita present did not have any clinical signs of Hexamitosis, but did have a good amount of body fat, and Hexamita does not typically cause problems in salmonids (Megan Finley, pers. comm., 2021).  It appears that the cutthroat population is functioning properly despite the presence of Hexamita and that the introduction of Hexamita along with cutthroat trout from below the falls will not lead to adverse effects to the population above Peekaboo Falls.  Presumably bull trout are equally susceptible to Hexamita, respond similarly to Hexamita, and are also functioning properly with Hexamita.  But without any direct evidence of Bull Trout susceptibility or response to Hexamita, we should proceed with a well thought out monitoring plan.

Brook trout have been observed in very low densities (1 to 5 fish) in 3 of 8 years below Peekaboo Falls, but not above. The furthest brook trout were observed in Box Canyon Creek was just below Big Pool Falls at RM 0.6. All of these fish were between 100 and 299 mm in length. The lack of fry observed indicates that no Brook Trout spawning occurred in Box Canyon Creek in the previous year. Some of the brook trout observed were captured and destroyed. Lodge Creek, a smaller tributary entering on the west side of Kachess Reservoir, is dominated by Brook Trout. It is presumed that those found in Box Canyon were explorers from Lodge Creek. Currently, Big Pool Falls appears to be a barrier to their migration further into Box Canyon Creek likely because they explore during low flows when Big Pool Falls is impassable. However, WDFW surveys are only done during base flows so there is potential for Brook Trout presence at other times of year when Big Pool Falls is passable. WDFW will continue to monitor box canyon for Brook Trout presence and euthanize any that can be captured.

Are there threats to the persistence of Bull Trout in the habitat above the falls that are significant enough that we would want to avoid establishing bull trout there until threats are reduced?

If Bull Trout adults are moved or allowed to pass volitionally upstream above Peekaboo falls, they will be exposed to more harassment and poaching because the reach above Peekaboo is more heavily used for recreation. Modifications to existing dispersed recreation and increased enforcement in the area is expected to mitigate this threat, as it did at Peekaboo Falls when it was closed to camping in the early 2000s. The USFS created a plan in 2016 to reduce vehicular access to sections of dispersed camp sites, reduce the size of overly large sites, reduce sediment input via road maintenance, and decommission unnecessary sections of roads.  Additional thought needs to be put into closing or moving some dispersed recreation sites and managing dispersed recreation sites more actively. As of 2023 the USFS continues to develop this plan and there are funding sources likely.

Before passage is implemented WDFW will explore changes in fishing regulations above Peekaboo falls to protect Bull Trout, such as fishing closures in some months or changes in gear types allowed. Additional habitat improvements are recommended in the reach above Peekaboo Falls including LWM placement and riparian vegetation plantings to both improve Bull Trout habitat and protect Bull Trout from harassment and poaching.  Large wood can provide hiding cover for Bull Trout, velocity refuge for young Bull Trout, and maintain ecosystem processes. Post-monitoring of a wood installation project in Box Canyon Creek below Peekaboo Falls suggests that wood allows Bull Trout fry to maintain rearing positions higher up in the creek and resulted in increased numbers of Bull Trout juveniles.

Next Steps:

Funding for Bull Trout transport alternatives is not explicitly provided, however, if capacity within the WDFW and MCFEG to do basic habitat assessments, fish rescues, fish assessments, and Bull Trout outreach and recreational dam removal continues and can be worked into the field work schedule, it may be possible to transport juveniles directly from Box Canyon Creek or the Kachess River above Peekaboo Falls. Other alternatives involving fry capture at the mouth of Box Canyon Creek during spring runoff followed by immediate relocation above Peekaboo Falls or captive rearing until they are older would require additional funds, or possibly a redistribution of funding within the Yakama Nation's current Bull Trout rearing and release program.

Funding for assessments of fish passage options currently and at future low flow scenarios at Big Pool Falls, Peekaboo Falls, and Bomber Falls is being requested from the National Fish Passage Program by Kittitas Conservation Trust in the 2024-2025 funding round. The USFWS's Recovery Implementation Grant will also be applied for in the 2025-2026 funding cycle.

Work by the USFS is scheduled to continue to develop changes to dispersed recreation in Box Canyon Creek, Gale Creek, and the Kachess River.