West Fork Environmental recently concluded two studies on the passage of resident coastal cutthroat trout through corrugated metal culverts. This research was conducted at the culvert test bed facility located at the Skookumchuck fish hatchery operated by WDFW. The passage trials utilized wild cutthroat trout from tributaries of the upper Skookumchuck River and were funded primarily by the National Council for Air and Stream Improvement (NCASI).
Our ability to control velocity, outfall drop and tailwater pool conditions permitted us to experimentally assess the dual influences of drop height and water velocity on the ability of fish to successfully enter and pass through the test culvert. Information from these studies is currently being validated using field trials to test passage of coastal cutthroat trout at culverts with drop heights and velocities similar to those tested at the culvert test bed facility.
This research will add to the growing body of literature that addresses the question of passage, partial passage and fragmentation for resident trout populations inhabiting headwater streams.
West Fork Environmental’s HDPE Pipe Antennas—Improving the Durability of Instream Antennas
As users of PIT tag technology we’ve seen our share of instream antennas get destroyed by winter weather. To solve this challenge we changed from the traditional glued PVC pipe used in NOAA-style antennas to fusion welded HDPE. This material and the fusion welds are extremely durable and withstand much greater impact than the housings made of PVC. We developed production systems to ensure that the HDPE antennas would perform as well or better than previous PVC models.
We recently installed several PIT tag antenna arrays using the new HDPE housings. These sites have already shown great promise in improving reliability of winter data by increasing the durability of the PIT tag antennas. We construct antennas in the standard 6, 10, 15 and 20 foot dimensions. We also make custom sized antennas and recently installed a 25 foot HDPE antenna in Pudding Creek, CA.
To demonstrate the durability of our HDPE antennas we suspended one 60 feet in the air from a crane and dropped it. Except for surficial scratches, the structural integrity of the antenna housing was undamaged and the antenna itself retained its high performance.
Vertical PIT tag antenna arrays: A prototype system for whole water column detection
Detection of PIT tagged out-migrating juvenile salmonids in relatively large natural rivers is problematic because available antenna systems are typically incapable of interrogating the upper portions of the water column where fish may travel. Low juvenile detection rates hamper studies of many kinds including those designed to understand population level effects of flow management and habitat restoration.
An antenna system that could detect fish through the whole water column would be invaluable in addressing the ever more specific questions posed by researchers employing RFID technology. We have developed an antenna system dubbed the FIN (Fish Interrogation Nodes) capable of detecting fish through the whole water column at variable river flows and stages. These arrays are composed of individual vertical antenna housings anchored to either the channel bed or an above water support system through an articulated shackle that allows for deflection and passage of debris and ice.
A partial array was recently installed on the Yakima River in the vicinity of Selah. Results to date indicate good debris shedding capability and tolerance for high flows. Significant noise issues initially encountered appear solvable with minor alterations to the anchoring and cabling approaches used in the prototype.
Field validation of experimental passage results: Describing the passability of bare corrugated metal pipes by coastal cutthroat trout
West Fork recently completed two studies testing the ability of cutthroat trout to ascend corrugated metal culverts using an experimental test flume. Results from these passage trials provided the empirical data necessary to describe the probability of successful passage over a range of hydraulic conditions (Peterson et al. 2013).
In order to broaden the applicability of these results, West Fork is currently validating passage probabilities through field-based passage testing in southwest Washington. The ability for a resident cutthroat trout population to pass through a culvert in situ is being tested by capturing, tagging, and releasing individuals in the vicinity of the culvert in order to track their movement. The research site is instrumented to record movement of PIT tagged individuals into and through the culvert as well as the stream stage and turbidity.
Initial findings have revealed the importance of high flow events in spurring movement and the conditions most likely to facilitate successful passage through the pipe. Results from this validation process will provide a greater context to previous experimental results, leading to broad applicability for headwater drainages across the Pacific Northwest.
Cedar River Sockeye Spawner Distribution Study
West Fork Environmental completed the first year of a three year study investigating the spatial and temporal distribution of spawning sockeye salmon in the Cedar River between Lake Washington and Landsburg Diversion Dam. Seattle Public Utilities has funded projects to sample sockeye otoliths at the Hiram Chittenden Locks and from broodstock collected for the Cedar River Sockeye Hatchery. Understanding how representative these samples are of the naturally spawning population in the Cedar River will aid in adaptively managing the hatchery.
Sockeye spawn in the Cedar River from late September into January and during this period West Fork staff surveyed the river collecting sockeye carcasses for otolith extraction and analysis. Physical measurements of all carcasses were collected and analysis of these data and origin data (as determined by thermal marks on otoliths) will assess whether the spatial and temporal distribution of naturally spawning sockeye differed for wild and hatchery origin individuals.
New Foster Dam PIT Tag Antenna Complete
Foster Dam on the South Fork Santiam River was outfitted 30 years ago with a spillway weir as a surface outlet for downstream migrating fish passage. The weir sits on top of stop logs inserted into a spill bay gate opening. The stop logs are used to regulate pool elevation and the weir provides a surface passage alternative for fish that has more benign hydraulic conditions than passage through either the turbines or open undershot spillway gates. The modified fish weir opening measures 22 feet in total width, 11 feet on either side of the center wall. Velocities across the weir increase from 11 fps on the leading edge to 37 fps at the trailing edge. In 2013 the USACE, Portland District, documented out-migrating juvenile fish moved through the modified fish weir throughout the year. However, until recently there has been no way to characterize movement patterns and provide detailed movement data of PIT tagged fish over the weir. In May 2014, a new PIT tag antenna, designed and installed by West Fork Environmental, began detecting PIT tagged fish moving over the weir. For the first time in 30 years fisheries managers are now able to collect detailed data to characterize the timing, number and life stage of winter steelhead, rainbow trout, and spring Chinook salmon moving downstream over the Foster Dam fish weir.
The all mild steel structure of the weir and stop logs and the need to maintain the existing hydraulic conditions over the weir constrained antenna design and construction options. Material choice was constrained by the requirement for a smooth, abrasion resistant weldable thermoplastic readily available in thick large sheets. Two 11-foot by 42-inch antennas were constructed using a jacket of ultra-high-molecular-weight polyethylene (UHMW-PE) with a core material holding both the ferrite shielding and Litz wire coils. The overall thickness of the antennas was limited to 2.5 inches. Each antenna weighs in at over 520 pounds. The antennas were positioned on the fish weir after it had been removed from the spillway by a crane and moved to a nearby work site. The antennas are each anchored to the mild steel weir deck by multiple stainless steel fasteners. Each component of the installation is mounted within the outside dimensions of the weir limiting the potential for damage to the components during reservoir elevation changes when the crane is used to reposition the weir and stop logs. The antennas are driven by IS1001-ACN’s and controlled by an IS1001-MC MTS. The installation and initial tests of this PIT tag antenna at Foster Dam proves there is great promise for thin body ferrite shielded antennas even at sites with technical challenges that include entirely mild steel structural components and high noise levels. Initial tests showed high tag read efficiencies at a water depth of 24 inches and a velocity range of 11 to 37 fps.
PIT Tag Antenna Installed at Cougar Reservoir Portable Floating Fish Collector (PFFC)
The U.S Army Corps of Engineers, Portland District, began operating a new experimental fish collector at Cougar Reservoir in May 2014 with the goal of attracting and collecting juvenile salmon as part of a research program investigating downstream passage issues at the dam. Past observations by biologists determined juvenile fish had difficulty passing the temperature tower because it was not designed for fish passage. The PFFC was designed by engineering firm HDR to be positioned near the temperature tower with an adjustable attraction flow of 50 to >100 cubic feet per second. Careful attention to the mooring and anchoring of the structure in a reservoir where the water can fluctuate up to 180 feet annually was required. A PIT tag antenna was designed and installed by West Fork Environmental with the goal of monitoring the collection of fish and provide information on the timing of collection. Groups of tagged fish will be released to estimate the combination of reservoir survival and trap collection efficiency. The PIT tag study is one of several related research efforts to evaluate surface passage at Cougar Dam.
Design and construction of the thin-bodied ferrite shielded antenna, constructed of high density polyurethane, was technical due to complex geometry of the steel walls of the PIT tag antenna slot located at the tail end of the collector portion of the structure. West Fork designed and installed the antenna, coordinated with HDR engineers, and adapted the design of the antenna as the collection facility plans progressed. The PIT tag antenna was designed to fit into a slot with opposing and uneven angles and that was constructed entirely of mild steel. The final antenna dimensions measured 2 inches thick by 6 inches wide and included specifications for sloped sides with several notches engineered into the antenna housing so that it could remain fully recessed within the available slot dimensions without disrupting hydraulics of the collector throat. The antenna is powered by a IS1001-ACN controlled through an IS1001-MC. The high noise environment generated from the operation of pumps presented another challenge in designing this particular antenna and was in part addressed with ferrite shielding on three sides of the coil. Data acquired from the PIT tag system on the Cougar Reservoir will be manually downloaded.
The PIT tag antenna, designed to easily remove from its slot, can be used to detect the effectiveness of the structure at collecting juvenile salmonids at other sites. The complex geometry presented in this particular setting, and the capacity to design and install a thin-bodied ferrite shielded antenna to these specifications shows that a good deal of flexibility is possible in fitting these kinds of antennas to various engineered structures.
West Fork annually engages in presence/absence fish surveys for its forestry clients to verify regulatory stream typing prior to timber harvest. Over the past ten years we have conducted over 3,500 protocol stream surveys for Washington clients alone, resulting in a large number of changes to portions of the Washington Department of Natural Resources hydro-layer. These changes have been submitted for review by our clients through Washington’s normal water type modification reporting process. Water typing field activities have been guided by the Washington Forest Practices Board Manual Section 13, “Guideline for Determining Fish Use for the Purpose of Typing Waters” and the input of regional state agency personnel and biologists employed by local Indian tribes. Because we have always managed our data through a GIS we maintain an electronic record of all the changes to DNR’s hydro-layer that result from our field surveys. The following table documents the type and total extent of the changes as a result of our work.