Center for Streamside Studies

and

Center for Urban Water Resources Management

2002 Annual Review
abstracts

Why do they care? Landscape management for nonpoint source
pollution by small parcel owners

Kathleen L. Wolf
kwolf@u.washington.edu

Nonpoint source (NPS) pollution has been deemed the principal remaining cause of water quality problems across the United States. NPS is any source of pollution not associated with a distinct discharge point. It can include sources such as rainwater, runoff from agricultural lands, industrial sites, parking lots, and timber operations.

Successful control of NPS pollution depends in large measure on multi-approach intervention programs. Combinations of education, technical and financial assistance, and regulatory measures are used to inform people about NPS issues and to encourage best management practices. The objectives of such programs are to prompt behavior changes in individual landowners that cumulatively can mitigate NPS pollution on a landscape scale. Knowledge about the psychological dynamics of behavior change may be a strategy to enhance delivery and acceptance of technical information about land management. Social science approaches are one way to discover how those who participate in programs come to care about land and water.

Nearly 500 intervention program participants responded to a survey on land management actions and attitudes in western Washington. This presentation describes results about psychological motivations and satisfactions associated with land stewardship. In psychological theory, motives are unobservable constructs derived from personal and external sources that both energize and direct human behavior. Satisfactions are experienced when motives are successfully expressed in actions or outcomes. Categories of participant motivations derived by data analysis include influences by external parties, a sense of responsibility, degree of action feasibility, and a sense of personal commitment, with the most important motivation being stewardship ethic. Reported satisfactions included experimentation on one's land, opportunity for social interaction, a sense that management practices were integrated into routines, and a sense of connection to larger landscape systems. While preliminary, these results suggest that appeals to the psychological dimensions of landowners, in conjunction with technical information, could boost recruitment and retention of participants, and enhance their sense of achievement while engaging in land stewardship activities.

A study of periphyton induced pH fluctuations in the
White River, Washington

Derek Stuart
dstu@alumni.washington.edu

The White River, located in southern Puget Sound, experiences pH spikes, which frequently exceed levels deemed healthy for salmonid fish. A combination of municipal wastewater and non-point dairy nutrient inputs prevent periphyton from being effectively limited by inorganic phosphorus or nitrogen concentrations. During daily periods of high primary production, periphyton draw CO² from the water, forcing bicarbonate ions to combine with hydrogen ions and form new carbonic acid (H²CO³ CO²). As hydrogen ions are removed from the river, pH increases. On days with high levels of photosynthesis, it is common for pH to spike from 7.0 in the early morning to 8.5 9.0 in the afternoon.

At levels above 9.0, pH has been shown to be both directly and indirectly toxic to fish, especially salmonids. The primary action of toxicity is driven by the toxic un-ionized form of ammonia, the concentrations of which increase at high pH. The White River frequently exceeds the current Washington State pH criterion of 8.5. Since this violation falls under the Clean Water Act, a Total Maximum Daily Load standard must be developed. In addition to violating the Clean Water Act, the White River also supports a threatened run of spring chinook (Oncorhyncus tshawytshcha).

From an extensive annual sampling program, trends of nutrient limitation were observed upstream of nutrient sources, and there were seasonal cycle of turbidity induced light limitation at sites downstream of nutrient sources. The collected data were used to develop statistical models of pH, periphyton biomass, total suspended solids, nutrient concentration, flow, and solar radiation, which may prove useful in predicting pH spikes on the White River.

Regional stream temperature estimation using thermal
infrared remote sensing and ground measurements

Keith Cherkauer
cherkaue@u.washington.edu

Stream temperature is a significant water quality concern in the Pacific Northwest, where warm water can be lethal for native fish species and cold water refugia are essential for the survival of threatened and endangered salmon. This necessitates regional-scale assessments of water temperature for compliance monitoring. These assessments have, however, been limited by sparse sampling in both space and time using submerged temperature-recording sensors. In the Puget Sound region, for example, the State of Washington relied on periodic data collected at 76 stations to assess water quality conditions for 12,721 km of streams and rivers (i.e., one station per 167 km of stream). We are evaluating the utility of remotely sensed thermal infrared (TIR) and visible images of streams and stream corridors for increasing the data coverage for stream temperature analysis and assessment. If stream temperatures can be estimated from images with known and acceptable levels of confidence, then regional temperature assessments will be less sensitive to the uncertainty associated with sampling temperature at a relatively small number of ground stations. Stream temperatures, energy, and water fluxes are monitored to evaluate their significance to the stream energy balance using a ground-based network of temperature data loggers, stream gauging stations, and meteorological observations. Logger temperatures have been interpolated between locations to produce hourly maps of the distribution of stream temperatures in the Green River. Thermal infrared images from the satellite based ASTER imager and the plane based MASTER imager collected in August of 2001 for the Green River are still being processed to obtain stream temperatures; however, images of raw brightness values are used to demonstrate the potential of both thermal imagers to view regional streams.

Effects of heavy metals from abandoned mines on
organisms in the Methow River

Daniel Peplow and Robert Edmonds
dpeplow@u.washington.edu

A three-year multidisciplinary study is being conducted on the relationship between mine waste contamination and diseases in fish and invertebrates in the Methow River, WA. Ore deposits in the area were mined for gold, silver, copper, and zinc until the early 1950s. In this study, Methow River sediment concentrations of zinc, lead, and copper increased from background levels above Twisp, WA, to over 4, 5, and 20 times background levels, respectively, below the Alder and Red Shirt Mills. Periphyton with entrapped sediments also contained higher concentrations of heavy metals compared to background levels, as did the whole-body metal content of the caddisfly larvae Ecclisomyia that graze on the contaminated periphyton. Thin sections of midgut epithelial cells from exposed larvae that were examined by transmission electron microscopy, and compared to cells from larvae not exposed to metal-rich periphyton, revealed the accumulation of electron-dense metals as granules in their mitochondria. Mitochondrial granules have also been found in juvenile trout in the Methow River. Laboratory tests have shown that the accumulation of cations by intact cell mitochondria disrupts cell metabolism and results in cell death (necrosis) as well as liver and kidney fibrosis. Exposed trout in the Methow River showed reduced growth and increased mortality compared to controls. Metal specific stains suggest lead is accumulating in the cartilage of trout gill filaments. Liver and kidney necrosis was also evident.

Land management for nonpoint source pollution: Methods and motivations

Clare M. Ryan
cmryan@u.washington.edu

States, territories and tribes, identify nonpoint source pollution as responsible for more than half of the nation's existing and threatened water quality impairments, making it the principal remaining cause of water quality problems across the United States. It is the result of actions by many different people, animals, or businesses, the combined effects of which can be significant in a particular body of water or watershed. Nonpoint source pollution control depends on educational programs and other activities that are undertaken by both government and non-government organizations. Combinations of education, technical and financial assistance, and regulatory measures are used to inform people about nonpoint source pollution issues, and to encourage the use of best management practices. Because implementation of land and water management activities is primarily voluntary, knowledge about the effectiveness of different methods of education and learning is critical to program design and delivery, and ultimately, implementation of appropriate land and water management activities. In coordination with several Conservation Districts, a questionnaire was mailed to landowners in western Washington who participate in land and water management programs and activities. While landowners experience many different educational techniques, they ranked interpersonal contacts as a more effective means of learning than other methods such as brochures, advertisements, or radio and television.

Landowners reported that they most often learned about activities by directly contacting the Conservation District or other organizations to get information; seeking information from books, journals, or the Internet; attending an on-site tour or demonstration; receiving a brochure or ad in the mail; getting information at fairs or other events; or being contacted directly by a representative from the Conservation District or other agency. While these were the most frequently experienced methods of learning, they were not the most effective methods of learning. When asked to rank effectiveness, the two most effective techniques were when an individual landowner contacted the Conservation District, or a representative from the District or other organization contacted the landowner. Attending an on-site tour or demonstration was also ranked as highly effective, along with receiving information from a community or professional group. While many land and water management programs are already heavily oriented towards personal contacts, this finding underscores the need to explore ways to incorporate interpersonal contacts and field activities into new or existing programs in a cost effective manner. One approach might be to shift scarce resources away from the less effective methods (brochures, ads, radio, and TV) and to invest them in the more effective interpersonal and hands-on educational techniques. In addition, because the initial contact and response between landowners and the organization providing information is such an important component of the learning method, organizations will want to ensure that an effective contact and response system is in place and functional.

A daily time series analysis of urbanization effects on stream phosphorus concentrations and transport

Sara Stanley
stanleys@u.washingon.edu

In natural freshwater ecosystems, phosphorus (P) availability often limits primary productivity. When P is present in excess, it may enhance the growth of algae and nuisance species like cyanobacteria, which lead to eutrophication. Research suggests urbanized watersheds export more nutrients (especially phosphorus) than do forested or undisturbed watersheds. The ability to model the movement of phosphorus through the environment would be a valuable tool for land use management, urban planning, and watershed restoration. Four highly resolved databases of phosphorus concentrations were compiled for three areas draining different land-use types within the Lake Washington/Sammamish watershed (highly urbanized, Thornton Creek, moderately urbanized, Swamp and North Creeks, and low density residential, Issaquah Creek). A database of daily observations of total phosphorus (TP) and total suspended solids (TSS) and weekly observations of soluble reactive P (SRP) were collected. North Creek had the highest phosphorus concentrations, even though Swamp and Thornton Creeks had greater percentages of urban land cover. A detailed time series analysis was used to develop models of stream flow and nutrient concentrations for each of the study streams. Model results were moderate to strong for SRP (r²=0.53-0.80) and weak to moderate for TP (r²=0.39-0.59). Because the dynamic behavior of TP concentrations change in response to storm events, this parameter was difficult to model. There were weak to moderate correlations between TP and TSS concentrations for log-transformed data (r²=0.20-0.47). Ultimately, these data will give us greater insight into how land use influences phosphorus export in the Lake Washington/Sammamish watershed and whether future increases of urban areas might lead to eutrophication problems in the receiving lakes.

Urbanization impacts on stream nutrient concentrations

Michael T. Brett, S.E. Stanley, G. Arhonditsis, D.M. Hartley, J.D. Frodge, and D.E. Funke
mtbrett@u.washington.edu

We conducted a statistical analysis of a long term record of stream nutrient and sediment concentrations for 17 streams in the greater Seattle region. The watersheds in this region are strongly dominated by either urban or forest land cover, with little agricultural area. Highly urban streams had on average 109% higher total phosphorus (TP) concentrations, 159% higher soluble reactive phosphorus (SRP) concentrations, 29% higher nitrate concentrations, and 71% higher ammonium concentrations during baseline conditions than non-urban streams. Turbidity was 72% higher in urban streams, while total suspended solids (TSS) concentrations did not vary with land cover. Stream geometric mean nutrient and sediment concentrations were for the most part weakly correlated during baseline conditions, except ammonium and turbidity, which were strongly correlated (r² = 0.81). During storm events TP concentrations increased (relative to baseline flow conditions) by 41 ± 26% (mean ± 1 SD), ammonium increased by 68 ± 36%, turbidity increased by 168 ± 74%, and total suspended solids (TSS) increased by 220 ± 113%. TP, ammonium, and turbidity were also higher in urban streams during storms. However, the concentration change during rainstorms for these constituents was not related to land cover. The responses of TP, turbidity, and TSS to rainstorms were strongly correlated (r² = 0.79-0.98). SRP and nitrate concentrations decreased during rainstorms by 11 to 25%, respectively, in urban streams and increased by 23 to 39%, respectively, in forest streams. These trends were related to land cover (r² = 0.55 and 0.67, respectively). This suggests that rainstorms wash inorganic nutrients out of forested watersheds. On a seasonal basis, turbidity and TSS concentrations peaked during winter high flows, SRP concentrations peaked during summer low flows, nitrate concentrations peaked during the winter, and ammonium concentrations peaked during the fall. Overall, our results suggest urbanization will increase stream dissolved inorganic nutrient concentrations by about 60 to 200% and will change the way stream inorganic nutrient concentrations respond to rainstorms. The nutrient enrichment we observed in our urban streams was substantially less than the nutrient enrichment in agricultural streams noted by prior investigations. Previously studied agricultural streams had about twice as much phosphorus and three times as much nitrogen as observed in urban streams. These results will be useful to predict how changing land use might affect stream nutrient transport and the potential for stream and lake eutrophication.

Opportunities for benign hydrologic design in urban areas

Richard R. Horner and Steven J. Burges
rrhorner@u.washington.edu

Research over the past 20 years has demonstrated that modified hydrology is the first and strongest agent of negative ecological change in Puget Sound's freshwater wetlands and streams as urbanization begins and progresses through the early stages. Water quality deterioration also occurs and assumes a larger role as impervious surfaces, population and vehicle densities, and industry grow. Declining biological health accompanying these stresses has led to legislative mandates requiring cities and counties to manage storm runoff water quantity and quality and participate in recovering salmonids. A highly developed city like Seattle has limited options to meet these mandates and must identify opportunities that fit its structure and provide demonstrable benefits. Opportunity identification and performance demonstration are the subjects of a research cooperative agreement between Seattle Public Utilities (SPU) and the Center for Urban Water Resources Management that began in 1999 and is currently authorized until 2004. The principal opportunities lie in the northernmost and southernmost portions of the city, where stormwater drains mainly in natural pathways, instead of pipes, and where most of the city's open stream reaches are located.
To date, benefit assessment has concentrated on two projects in the Pipers Creek watershed of northwest Seattle. The Viewlands Cascade project converted a confined, partially concreted ditch, where rapidly flowing runoff often left the channel and eroded a steep bank, to a broad, stepped, vegetated swale. The expanded cross section and slope adjustment substantially reduced velocities, and the greater soil contact increased the opportunity to infiltrate water into the ground. Data from the 36 storms processed to date demonstrate that, with relatively low soil moisture, the swale retained 78% of the runoff from the 10.5-hectare (26-acre) catchment and, in the wetter season, 34%. There are no monitoring data to compare how the former ditch would have performed, but a mathematical "hindcast" was applied to make estimates, assuming the old ditch operated under the same conditions as the new swale.

This exercise estimated the overall runoff coefficient to decrease from approximately 0.19 only to 0.15, but this marginal change still represented about 1400 m³ (50000 ft³) of runoff during the period monitored that did not immediately enter Pipers Creek, instead mostly feeding in gradually through the ground. Water quality benefits were not assessed quantitatively but include capture of solids and oils and related pollutants by vegetation and soils and reduced pollutant loadings to Pipers Creek and Puget Sound in proportion to the flow volume decrease. A full meteorological station at this site is gathering data for eventual development of a computerized hydrologic model for use in making management decisions for the watershed.

The second project being assessed is a street reconstruction (dubbed by SPU "Street-Edge-Alternatives [SEA] Streets"). Street width was reduced by 1.8 m (6 ft), and much of the saved space as well as other right of way was given to vegetated runoff storage ponds and swales. Monitoring of the discharge from the 0.9-hectare (2.3-acre) catchment before (March-July 2000) and after (March-July 2001) reconstruction, which were periods of comparable rainfall showed that the project cut the runoff coefficient by a factor of 50, attenuating almost all runoff. Performance of both projects continues to be monitored in the wetter conditions existing in the 2001-2002 winter.

Opportunity identification has taken a systematic approach to finding places where these and other types of projects could be installed for hydrologic and water quality benefits. One effort classified and prioritized a range of vegetation- and soil-based stormwater best management practice opportunities based on the attributes of street rights of way and other city-owned property. A second effort concentrated on opportunities for upgrading street-side ditches to produce water quality benefits, while maintaining their conveyance function, and developed design and maintenance protocols for this purpose. Both instruments were created for application with SPU's geographic information system (GIS) to locate the most suitable and potentially beneficial projects.

Assessing the availability of spawning gravel in an urban creek system

Chase Barton
cbarton@u.washington.edu

Changes in land use and hydrology resulting from urbanization alter the processes of sediment production, delivery, and transport within a watershed. As part of a multi-phase project to improve instream habitat, a sediment budget is being developed for the Pipers Creek watershed, a 7.5-km² urban watershed in Seattle, Washington. Pipers Creek supports multiple salmonid species, yet channel armoring and hillside stabilization may threaten the long-term availability of adequate spawning gravel in the stream. Sediment-delivery rates for park and urban components of the watershed, determined through field observations and measurements, include contributions from slope failures, channel enlargement, gully erosion, soil creep, and urban runoff. Instream channel surveys provide estimates of in-channel sediment storage in addition to substrate composition and character; initiation of motion calculations predict substrate stability at various points within the creek system. Together, these data display current patterns in the quantity, quality, and distribution of sediment within the creek system and demonstrate the likely imbalances in both coarse and fine sediment delivery and transport.

Variability of hyporheic flows in Puget Sound lowland streams

Cathy Reidy
creidy@u.washington.edu

Hyporheic exchange is the interaction between stream and shallow ground waters, occurring in the saturated sediments beneath and alongside streams. Hyporheic zones link aquatic and terrestrial systems and provide increased temporary water storage, allowing high rates of biogeochemical reactions. These zones also harbor a diverse community of invertebrates. Areas with strong hyporheic gradients are often selected by anadromous fish for redd locations.

I selected seven streams to examine the variability of hyporheic flow rates and water quality in the Puget Sound lowland streams. The objectives of this study are to 1) establish the presence or absence of hyporheic zones in Puget Sound lowland streams, 2) determine the seasonal variability of hyporheic flows in these streams, and 3) to assess water quality in these hyporheic zones. Although land-use effects are not the major focus of this study, the seven streams are located in basins that range from highly urban to largely forested.

Rates of exchange and cross-sectional areas of hyporheic zones were estimated by matching observed solute transport rates from tracer (NaCl and Rhodmine WT dye) injections to rates predicted by the USGS One-Dimensional Instream Solute Transport model (OTIS-P). Because OTIS-P does not distinguish between hyporheic and other instream transient storage zones (e.g., backwaters, eddies), I visually estimated surface area of instream storage zones for more accurate interpretation of model estimates. I collected hyporheic water quality samples from shallow piezometers (30 cm depth) within the active channel, and measured dissolved oxygen, temperature, pH, vertical hydraulic gradient, and fine particle percentages.

Protecting physical stream channels with classic
stormwater mitigation: Fact or fantasy

Karen Comings
kcomings@u.washington.edu

The overall scope of this project provides an opportunity to demonstrate the effectiveness of stormwater mitigation to protect downstream channels. Two urban planned developments (UPDs), Redmond Ridge and Trilogy at Redmond Ridge, are under construction near the city of Redmond, Washington. These two adjacent developments cover 860 ha, which overlaps nine separate watersheds. Prior to the start of construction in 1998, this site typified "undisturbed" conditions of the late-20th century in the Pacific Northwest: covered with mature second-growth forest and with many large wetlands that serve as headwaters for nine streams. Construction of the UPDs will introduce an estimated 20 to 50% of new impervious surface area. Mitigation for the anticipated "flashy" urban hydrology has been developed over the past several decades, primarily using large stormwater ponds that can temporarily store and partly control the timing of surface water runoff at specific sites. These two UPDs are no exception, with close to fifty ponds being built on-site. They provide an exceptional opportunity to evaluate the effectiveness of this approach for mitigating hydrologic changes.

Data are being collected for both stream hydrology and physical channel structure to compare instream geomorphic conditions prior to construction with those seen after the development is built. Many physical channel parameters, however, such as bank stability, embeddedness, and channel cementation, are notorious for high variability. Much of this variability is truly part of the population being measured, but error is introduced in most data sets because of the difficulties with observer bias and repeatability. These difficulties can come from subjective differences between personnel and inconsistencies in measurement methods from year to year. Subjective metrics can often be improved with the use of categorical data collection. Some sensitivity is thus sacrificed to achieve better repeatability, a strategy that can be evaluated only after several years have passed. One aspect of this study is to investigate the level of sensitivity and repeatability that can be achieved by categorical data for bank stability and cementation; a second is to evaluate the most reliable means of measuring embeddedness by more quantitative metrics.

The development and organization of old growth river valley forests

Kevin L. Fetherston, Philip M. Hurvitz,
and Tim B. Abbe
kfetherston@earthlink.net

Our research focused on identifying the physical and biotic processes controlling the generation and maintenance of the valley forest mosaic on a 3-km-long reach of the Queets River in Olympic National Park. Utilizing archival data (historic aerial photographs) and field surveys we examined: (1) floodplain and terrace overstory forest composition, structure, and distribution, (2) channel migration patterns, and (3) distribution and orientation of stable wood jams. Archival data indicate a dynamic channel migrating at a rate of 4-5 meters per year. Large trees recruited to the channel were fluvially organized into stable wood jams with key member trees aligned parallel to channel flow direction. Floodplain vegetation reproduction data indicate that the primary site of conifer tree reproduction is on stable wood jams, whereas deciduous trees reproduce exclusively on mineral and humus substrates. Field surveys of terrace overstory trees indicate a 250 year old mixed conifer-deciduous forest mosaic with conifer patches comprised of overstory conifer tree colonnades aligned in a nonrandom pattern with mean colonnade orientation parallel to the adjacent valley wall axis. Our findings suggest that initial floodplain colonization conditions, with fluvially organized large wood as the limiting factor controlling conifer reproduction, form a habitat template that controls the development and organization of floodplain and young terrace forests and the subsequent production of future stable wood jam key member trees. We call this biogeomorphic feedback process the forest river wood cycle.

Spawning salmon as forest fertilizer:
Effects on riparian structure and composition

Krista Bartz
kbartz@u.washington.edu

Spawning Pacific salmon (Oncorhynchus spp.) contribute nutrients to freshwater and terrestrial ecosystems. The dispersal of these nutrients through aquatic food webs and the ensuing effects on instream productivity have been extensively noted, yet parallel impacts to streamside systems have been reported only recently. The goal of this study was to investigate the role of salmon nutrients in determining riparian forest structure and composition in southwest Alaska. Ten spawning streams spanning three major watersheds were examined during the summer of 2000. Each stream had a natural barrier to upstream salmon migration but limited geomorphologic differences across the barrier, enabling comparisons between reaches with and without salmon. We found that few soil nutrient parameters differed significantly with the presence of salmon, and of those that did, only ¹⁵N was elevated. Foliar nutrient parameters showed similar trends. Composition was indistinguishable based on salmon presence or absence, yet structural characteristics differed throughout all layers. Specifically, overstory stem density was higher near spawning reaches, while understory stem density and ground layer and diversity were lower. These differences were best explained by environmental factors including, but not limited to, salmon.

When is hydrologic maturity:
Inferring temporal change in hydrologic response from paired streamflow data

Finn Krogstad
fkrogsta@u.washington.edu

To avoid creating watersheds dominated by young hydrologically immature stands, we need to know how old a forest has to get before it is hydrologically more like a "mature" forest than like a clearcut. It would also be helpful to know how this maturation proceeds over time, whether it is linear, exponential, sigmoid, or some other form. Previous studies (Jones and Grant 1996, Thomas and Megahan 1998, Beschta et. al 2000) have used paired watershed peak stream flow data to evaluate the magnitude and statistical significance of harvest impacts on peak stream flow. In these studies, the nature of this hydrologic maturation was inferred either from storm events binned into distinct 5-year periods, or by assuming exponential decay of peak stream flow size over time.

The temporal component of this hydrologic maturation might be better inferred by incorporating basic physical understanding of stand re-growth. Stand properties such as height, density, and biomass tend to change in one direction as they grow and tend to be "similar" to those of the years immediately before and after. A Bayesian framework can be used to incorporate these unidirectional and "similar" growth properties into regression models that have been used to analyze these data. Incorporating these stand growth properties into analysis of data from the small H.J. Andrews clearcut and patch-cut basins suggest that the post-harvest peak flow increases may not be confined to the smaller events.

In evaluating the impacts of logging, past analysis has focused on changes in treated basin flows as a function of the corresponding control basin flows. Previous analysis has used this approach to suggest that effects of logging either are or are not confined to small events. The real question, however, is not the size of flow as related to the control basin, but rather the probability of exceeding a given size flow, independent of the corresponding size of the peak stream flow in the control basin. In the case of the small 100% clearcut H.J. Andrews basin, peak flows with pre-harvest return periods longer than 2 years were more than twice as probable after harvest, and this post- to pre-harvest ratio increases with peak flow size.

Short-term suspended-solid concentrations from stream crossing restoration work in the Clearwater National Forest, Idaho

Tim Brown
tmbrown@u.washington.edu

In an effort to address road maintenance budgetary constraints, the United States Forest Service has dramatically increased the number of road networks recommended for treatments that ultimately reduce or eliminate their associated environmental impacts. Consequently, more Forest Service roads are being treated annually with prescriptions ranging from temporary storage (e.g., culvert removal and impasse) to full recontouring of the hillslope. An increase in this type of work provides ample opportunity to study the short and long-term environmental impacts of these treatments. Information of this type will ultimately help in the development of Best Management Practices (BMPs).

The Clearwater National Forest in Idaho has some of the highest road densities in the nation. Their road obliteration program is nationally renowned for its methods. Five road-stream crossings in the Wendover basin of the Clearwater NF were monitored while the crossings were being removed (obliterated) and the stream restored to design specifications. Random grab samples above and below each crossing were taken to determine suspended-solid concentrations and durations attributable to each treatment. The volume of sediment deposited behind the sediment traps was estimated and added to the estimates of the volume of sediment in suspension to determine the total volume of sediment potentially contributed to Wendover Creek, a stream with ESA listed anadromous species. Turbidity was measureed in a subset of the samples in the lab and compared to regulatory values.

Ten years after: Evaluation of restoration efforts

Mark Muir
mmuir@u.washington.edu

The Little Naches River in the Yakima River drainage has a long history of intensive land management. Jenelle Smith assessed stream conditions in 1990, and since then a series of instream, riparian, and hillslope restoration projects have been initiated. To assess the results of the restoration projects, sites evaluated in 1990 were resurveyed. A similar survey was conducted in the American River, a basin with minimal land management activities, which will provide information on habitat conditions and natural processes that existed historically in the area.

As expected, the American River exhibited more complexity and diversity of habitat than the Little Naches. LWD counts were nearly double, percent pool cover greater, and side channel habitat more abundant. Channel processes were more dynamic in the American River as evidenced by channel migration, a high percentage of unvegetated gravel bars, and good floodplain connectivity. The American River also had lower measures of embeddedness and fine sediment (<0.85 mm).

In the Little Naches, fine sediment levels showed an encouraging trend, decreasing over the 10 year period. LWD cabled within the wetted channel was generally not effective in providing long-term habitat or refugia. Many cabled logs had been removed by high flows or covered by aggradation. In general, results show that restoration efforts should expand beyond instream structures and account for sediment production and habitat forming processes functioning at the watershed scale.

Flow regimes of char spawning streams:
Implications for bedload scour during the incubation period

Jeff Shellberg
jshellbe@u.washington.edu

In contrast to contemporary theories, many streams in western Washington with suitable temperature regimes do not contain spawning or rearing bull trout (Salvelinus confluentus). The goal of this study is to investigate factors apart from stream temperature that may influence bull trout spawning distribution, such as watershed flow regime, sediment transport regime, channel type, and habitat unit availability. It is hypothesized that fall spawning bull trout with shallow to moderate egg burial depths and long incubation periods are prone to bedload redd scour during winter rain and rain-on-snow events in western Washington. In order to assess the watershed flow regimes of bull trout spawning streams, peak-over-threshold flow data for 50 watersheds in the Pacific Northwest were analyzed to determine the mean, variance, and probability of peak flow timing.

The results show that some watersheds are prone to fall-winter peak flows, during which incubating bull trout eggs might be susceptible to bedload scour. Timing and predictability largely depend on how much and for how long precipitation is stored in the form of snow in a watershed. Snow dominated watersheds tend to have the largest time lag in peak flow timing and the lowest predictability that peak flows will occur during the incubation period. Watersheds with predictable peak flows during the incubation period should be the least suitable for spawning due to a high likelihood of bed disturbance. Other geomorphic and biologic factors influence the susceptibility of bull trout to extensive bed disturbance and redd scour. Preliminary results from the N.F. Skykomish River and the S.F. Skokomish River during water year 2002 indicate that scour depths in selected redd sites vary significantly between side channel, protected main channel, and unprotected main channel redd sites. Thus, the distribution and availability of diverse fluvial spawning habitat may be able to offset potentially unsuitable flow regimes.

Multi-scale prioritization of available riparian habitat
restoration and preservation opportunities

Raymond K. Timm, Robert C. Wissmar, John Small, Thomas M. Leschine, and Gino Lucchetti
raytimm@u.washington.edu

Quantifying the spatial complexity and distribution of landscape features reveals patterns that can be used in management decisions. We constructed a spatially explicit, multi-scale model to quantify the potential for restoration and preservation within the riparian zone of salmonid-bearing streams in the lower Cedar River drainage. Through a simple linear, additive model, we quantified the spatial coincidence of selected habitat variables in conjunction with selected human-imposed artificial constraints. We were able to produce a synoptic view of the location, size, and relative quality of riparian habitats for the entire lower Cedar Basin. A spatial weighting method was applied to emphasize the influence of areas in direct proximity to salmonid-bearing streams. In this way, the model was used to quantify relative habitat importance in the riparian zone along salmon streams within the basin.

Nonmigratory coastal cutthroat trout:
Evidence for restricted gene flow among neighboring creeks

Josh Latterell
latterel@u.washington.edu

I used variation in allele frequencies at 8 microsatellite loci to assess fine-scale genetic population differentiation and diversity of nonmigratory coastal cutthroat trout (Oncorhynchus clarki clarki) in 20 coastal headwater streams draining unlogged and clear-cut forests of the Cascade Mountains near Puget Sound, Washington. Highly significant differences in genotypic frequencies were observed in all multilocus pairwise comparisons. Strong population subdivision was observed (mean ST = 0.283; range = 0.024 to 0.656). The proportion of genetic diversity attributable to variation among populations within river drainages was twice that due to differences between river drainages. Genetic diversity was variable but indistinguishable in unlogged and clear-cut sites. My results indicate that nonmigratory coastal cutthroat trout populations in mountain river networks exhibit stronger genetic differentiation than anadromous populations, even among adjacent creeks. These findings indicate that many demographically independent, genetically distinct populations may occur in a single river network. The high level of genetic differentiation is likely attributable to rapid genetic drift, fueled by a suite of abiotic and behavioral factors that reduce the number of successfully reproducing adults in each population. Conservation of genetic diversity in coastal cutthroat trout populations will require the protection of dense "constellations" comprised of numerous populations within large channel networks.

The phylogeny of behaviour: Salmoninae spawning patterns

Manu Esteve
manu19b@u.washington.edu

I am studying and comparing the spawning behaviour of species from the Salmo, Oncorhynchus, and Salvelinus genera. The main objective is to match the possible similarities and differences of the Salmoninae species while spawning to their position in the phylogenetic tree. Based on the assumption that the more closely related species will share the most common behaviours during reproduction, a new hypothetical Salmoninae phylogenetic tree will be drawn. The study will be useful to better understand the unknown mating patterns of some of the salmoninae and to determine the feasibility of using behavior as a phylogenetic tool.

In rivers in Washington State and British Columbia, a video camera inside an underwater cage and placed 1.5 m from the salmon redds will continuously record the spawning activity. This information will be combined with video from other scientists working on spawning behavior. In addition, controlled experiments will be done at the Big Beef Creek Research Station (University of Washington) spawning channel.

The data collected during spawning will help determine the presence or absence of different behaviors among the species. As secondary objectives the project will investigate some significant patterns during spawning and the possible barriers preventing hybridizations. Also, the intensity of common behaviours will be categorized and tabulated in different ranking orders.

At Big Beef Creek, the possibility of controlling the number of mates in the spawning channel allows observation of female choice and male-male competition. I will record observations of different kind of matings (e.g., a single female with a single male vs. one female with two or more males). Spawning intensity will be measured to determine the assortative mating hypothesis (e.g., female and male of similar size versus female with smaller male). I will also try to observe the barriers preventing hybridization when placing pairs of chinook-coho, chum-coho, and chinook-chum in the channel. Finally fish wood models would be used to test some stimulus-chain reactions.

Changing temperature regimes and the
spawning timing of coho and chinook salmon

Thomas Quinn
tquinn@u.washington.edu

Spawning date is a crucial life history trait in fishes, linking parents to their offspring and is highly heritable in salmonid fishes. We examined the spawning dates of coho and chinook salmon at the University of Washington (UW) hatchery for trends over time, and compared the patterns to the changing thermal regime of the Lake Washington basin, to the patterns of spawning date for conspecifics at two nearby hatcheries. The mean spawning dates of both species have become earlier over the entire period of record at the UW hatchery (since the 1950s for chinook and the 1960s for coho salmon), apparently because of selection in the hatchery. Countering this selection, water temperatures experienced by salmon migrating in fresh water to the hatchery and holding there prior to spawning have become warmer. Spawning takes place even earlier at the Soos Creek hatchery, the primary ancestral source of the UW populations, and at the Issaquah Creek hatchery. Both species of salmon have experienced marked shifts towards earlier spawning at both of these hatcheries, despite the expectation that warmer water would lead to later spawning. Thus inadvertent selection at all three hatcheries appears to have resulted in progressively earlier spawning, overcoming selection from countervailing temperature trends.

p o s t e r s
graduate student research

Evaluation of North Creek channel conditions

Ashley Adams, Jeff Shellberg, and Leslie Wall
cssuw@u.washington.edu

The North Creek ecosystem restoration-at the University of Washington Bothell / Cascadia Community College campus located in Bothell, Washington-is one of the most ambitious and complex urban stream restoration projects in North America. By the early 20th century, the campus site had been logged, and North Creek straightened, leveed, and transformed into a log flume for timber transportation to the Sammamish River and downstream market in Lake Washington. These alterations effectively decoupled North Creek from its floodplain, minimized channel length, removed the adjacent floodplain forest/shrub/emergent plant community, plowed under floodplain microtopography, and removed in-channel wood. In short, the naturally occurring ecosystem functions of North Creek, and the adjacent floodplain, were to a significant degree diminished or eliminated.

Given the highly degraded nature of the site, the goal of the State of Washington was to enhance the campus landscape while meeting all federal, state, and local regulatory requirements to the mitigate impacts of campus construction. To accomplish this, a restoration design was developed with the following objectives: (1) reconnection of North Creek with its floodplain, (2) reintroduction of both in-channel and floodplain large wood, (3) restoration of a native forested floodplain plant community, (4) restoration of aquatic and terrestrial habitat, and (5) use of regional reference site data from throughout the Puget Sound lowland to guide the ecosystem design. (For more information and to see the rest of this article, see Kevin Fetherston's article in Streamside Runoff, Vol. 11 No. 1.)

An important component of any restoration endeavor, monitoring evaluates the success of project goals. Students from the Center for Streamside Studies and the Center for Urban Water Resources Management are monitoring how the stream channel morphology responds to channel relocation, floodplain reconnection, and in-channel rehabilitation structures (large woody debris). Thirty-eight cross-sections of channel elevation and position were surveyed in fall 2001 along three major stream meander beds with extensive large woody debris and engineered debris dams. Preliminary results from January 2002 resurveys indicate that the channel is slowly adjusting to its new position. While no major channel change occurred (e.g., avulsions or major translations) following several moderate storm events, up to a meter of both channel incision and point bar fill occurred in several sections.

Regional Riparian Stand Cooperative

Eric Beach
cssuw@u.washington.edu

Present land management regulatory frameworks place a great emphasis on riparian protection. Current forest practices in the Pacific Northwest are based on resource objectives or performance targets determined by the presumed successional or growth trajectory (pathways) of riparian stands. Because detailed information characterizing riparian stands is currently very limited, riparian stand growth is projected using empirical forest growth and yield models based on data collected from upland stands. However, incremental growth and mortality data collected in these areas may not accurately reflect stand dynamics in riparian zones. Factors such as soil moisture, frequency and intensity of disturbance, or site productivity may contribute to riparian stand conditions that differ greatly from upland areas. Reliance upon data collected in upland stands to predict how riparian stands function may lead to inaccuracies in predicted or presumed riparian conditions. In order to ensure that resource objectives accurately reflect natural processes, riparian growth data are needed to validate and refine growth models and increase the understanding of how riparian forests establish, grow, and die.

Recognizing the critical need for coordinated research and a database to manage the information, the Center for Streamside Studies and NCASI (National Council for Air and Stream Improvement, Inc.) have provided the initial funding for a Regional Riparian Stand Cooperative (RRSC). The mission is to provide a long-term source of high-quality information on successional dynamics (establishment, growth, and mortality) of riparian forests and the effects on the riparian ecosystem and associated aquatic environments. The RRSC would provide a structure through which data can be collected, analyzed, and shared across the region, including northern California, Oregon, Washington, and southern British Columbia. The effort would specify standardized proto cols for data collection and provide a single location where these data would be stored and maintained.

The formation of a riparian research cooperative enables stakeholders to leverage research dollars, develop standardized methods, and sample across the landscape of the Pacific Northwest. The product would be high quality, comparable data collected with standards suitable for use in trend monitoring, adaptive management, and research purposes and long-term research sites suitable for current and future ecological studies and adaptive management trials. Such an undertaking is probably beyond the means of any one organization, but could be accomplished through a collaborative effort.

Hydraulic control on downstream coarsening in headwater channels

Chris Brummer and David Montgomery
cbrummer@u.washington.edu

Most low-gradient, gravel-bedded rivers display an exponential downstream decrease in median bed-surface grain size (downstream fining) attributed to hydraulic sorting and abrasion. Here we present field data collected from stream surveys in three drainage basins of the Pacific Northwest that document downstream coarsening in small headwater channels. Our results support the hypothesis that median bed-surface grain size (D₅₀) is hydraulically controlled by watershed-scale variations in unit stream power (the drainage area-slope product per bankfull channel width), which is usually assumed uniform along a channel profile. Both D₅₀ and unit stream power increase downstream and attain maximum values at a drainage area of ~1 km² before decreasing in the downstream direction. In each of the three study basins, the unit stream power maxima correspond with the inflection point of the drainage area-slope relation thought to represent the transition from debris flow-dominated headwater channels to fluvial-dominated valley reaches. Comparison of field data from an intensely managed basin with data from a neighboring, unmanaged basin of similar climate, topography, and lithology suggest that sediment loading increases the variability of D₅₀ and inhibits the development of downstream coarsening in headwater channels. Although identification of the fundamental transition from headwater channels to alluvial channels is important for understanding controls on the disturbance ecology of mountain streams, the routing of sediment through mountain channel networks, and ultimately landscape evolution, very few geomorphological studies have addressed the nature of this transition. Controls on the morphologic aspects of this transition are being explored through DEM analyses of network-wide unit stream power for comparison with field surveyed grain size, channel width, and unit stream power relations.

Microbial production in the hyporheic zone of a coastal floodplain river

Sandra M. Clinton and Rick T. Edwards
sclinton@u.washington.edu

Microbes living on saturated sediments influence stream ecosystem processes by altering the amount and chemical composition of materials delivered from the watershed to the river. Although many factors control rates of microbial processes, available dissolved organic matter (DOM) is often a limiting factor. This limitation is of key interest in the hyporheic (subsurface) zone where microorganisms are dependent upon allochthonous sources of DOM for respiration and production. In floodplain rivers, long hyporheic flowpaths (hundreds of meters) occur beneath productive riparian terraces. At this scale, advecting DOM is rapidly utilized at the head of the flowpath, leaving a large proportion of the hyporheic microbial community potentially DOM limited. An alternative source of labile DOM, however, infiltrates from overlying riparian soils.

We investigated how variation in DOM and microbial activity were related to differences among the successional stages of overlying vegetation and positions along flowpaths in the hyporheic zone of a floodplain terrace on the Queets River, WA. Samples for dissolved organic carbon (DOC) and microbial production were collected seasonally from 30 wells during 2000-2001. Dissolved organic carbon ranged from 0.5-2.0 mg/L over the year and was higher in wells overlain by mixed old-growth conifer than young alder. Microbial growth experiments demonstrated that hyporheic microorganisms were capable of metabolizing riparian soil leachates. Microbial production was higher at the head of the flowpaths than the end of the flowpaths; however, it did not decrease in a fashion predicted from other studies. Although microbial production was higher in wells overlain by older trees, production was not statistically related to the overlying patch structure. The inconsistent patterns of microbial production along flowpaths and among successional patches demonstrate that neither advecting surface water nor riparian soil inputs completely determines rates of microbial activity in the Queets River floodplain hyporheic zone. Instead, subsurface production reflects a mixing of DOM sources that result in a heterogeneous pattern of microbial activities.

Effect of marine-derived nutrients on aquatic macroinvertebrate
production in a salmon spawning stream

Jon Honea
jhonea@u.washington.edu

I hypothesize that salmon spawning activity affects macroinvertebrate production. To test this hypothesis, macroinvertebrate production will be estimated from monthly benthic macroinvertebrate samples collected over two years from Kennedy Creek, WA above and below a natural barrier to spawning salmon. Preliminary analysis shows that the stream bed disturbance caused by salmon spawning activities severely affects the macroinvertebrate community, reducing densities and diversity. However, after the spawning disturbance ends, the macroinvertebrate community density in the downstream spawning reach approaches or exceeds upstream density with no spawners. Recovery is likely aided by fertilization of the stream by marine nutrients released from spawning and decomposing salmon, as indicated by stable isotope analysis showing substantial quantities of marine carbon and nitrogen in downstream insects shortly after spawning had ceased.

Short-term tree fall patterns from riparian buffers

Mike Liquori
mliquori@uswest.net

Managing riparian zones to provide aquatic ecosystem functions has become a fundamental component of forest stewardship. We often seek to inform riparian management through our understanding of native forests. Yet, few studies have sought to capture key differences in ecological and geomorphic processes between buffered sites and fully forested conditions. This study examined residual buffer conditions from 21 randomly selected harvest sites within the Kapowsin Tree Farm in the western Washington Cascade Mountains west of Mount Rainier.

A comparison of large woody debris (LWD) recruitment processes suggests that recruitment patterns shift away from the channel under buffered conditions, likely in response to changes in the dominant tree recruitment process associated with buffer edges. Treefall rates in buffers in the first years following harvest average 308±261 trees/km/yr, roughly 20-60 times the rates observed in along similarly aged forested riparian zones. While tree fall rates vary by species and recruitment process, tree fall directions follow a strong non-random preference toward a perpendicular orientation to the channel in both buffered and forested conditions. Despite this tendency, only 20% of the trees deliver to the channel, and only 7% act to modify the channel.

These results suggest the need to modify many of the LWD recruitment models that derive rates of LWD recruitment with random treefall direction and limit post-harvest windthrow assumptions. Such shifts in recruitment process may also result in large long-term shifts in available riparian function in response to changing stand growth trajectories.

Genetic and life history differences in sockeye salmon spawning in the mainstem and an off-channel pond of the Cedar River

Jennifer McLean and Julie Hall
jenm34@u.washington.edu
jlhall@u.washington.edu

The Cedar River, located within the Lake Washington basin, contains sockeye salmon (Oncorhynchus nerka) that exhibit variation in their spawning and rearing strategies. Sockeye spawning in the mainstem Cedar River exhibit typical "lake-type" behavior: the adults spawn in the river and the juveniles migrate to Lake Washington for rearing directly after emergence. A portion of sockeye in the Cedar River system use off-channel ponds for spawning, and we examined their offspring for unusual life-history characteristics. Offspring of adults spawning in our study site, Wetland 79, exhibit two different rearing behaviors: a portion follow the standard lake rearing strategy and migrate to Lake Washington soon after emergence, while the others remain in the pond for an extended period. These different juvenile rearing strategies are consistent with two sockeye life history types that are found throughout their geographic distribution. Juvenile "lake-type" sockeye rear in lakes, and "river-/sea-type" sockeye spend more time in the river as juveniles. Populations that exhibit these different life histories are genetically distinct.

Are the two groups of sockeye that we observed in Wetland 79 genetically distinct? We used five highly polymorphic microsatellite loci to investigate whether genetic differences exist (1) between the sockeye using the mainstem for spawning and those using the off-channel pond (Wetland 79) and (2) within the adult sockeye population using the pond for spawning. Our data are consistent with genetic differentiation between the sockeye spawning in the river and in the off-channel pond (F_ST = 0.024); however, there may be two distinct groups using the off-channel pond. An iterative assignment process was used to determine if two genetically distinct groups exist in Wetland 79. Preliminary genetic analysis suggests that there are two groups spawning in the off-channel pond. To confirm that these two genetic groups correspond to the two rearing strategies, we intend to sample juveniles of each rearing strategy. A further comparison of samples from the pond and from known river-/sea-type populations will be made to determine if this is a recent divergence or an ancestral strategy.

Impacts of riparian vegetation on in-stream
ecosystem and nutrient dynamics

Carol J. Volk, Peter M. Kiffney,
and Robert L. Edmonds
cvolk@u.washington.edu

Riparian vegetation provides an important subsidy of organic matter and nutrients to aquatic ecosystems. In the Pacific Northwest, the predominance of red alder (Alnus rubra) in riparian corridors is a consequence of clearcutting and other natural disturbance events (e.g., floods and fire). Red alder is a pioneer species that has a symbiotic relationship with a nitrogen fixing endophyte in its root system. Streams supplemented with nitrogen from adjacent red alder stands can have elevated primary production that can be transferred to higher trophic levels such as fish and amphibians. In the fall of 2000 and spring of 2001, we sampled leaf litter, water, seston, and periphyton from six headwater streams on the Olympic peninsula in Washington; three streams were dominated by red alder and three by old-growth coniferous forest. Biomass and nutrient composition (C, N, and P) measurements were made to estimate instream food resource quantity and quality. In addition, vegetation, periphyton, invertebrate, and amphibian samples were collected for ¹³C and ¹⁵N stable isotope analyses from two streams dominated by red alder and two streams dominated by old-growth conifers in June 2001. We found alder leaf and conifer needle C:N ratios were about 20 and 60, respectively. Chlorophyll a and periphyton ash-free dry mass were significantly different between alder and conifer sites and among seasons. Seston biomass was predominantly driven by precipitation events, but almost twice as much particulate C (15.8% and 8%) and N (1.03% and 0.45%) was measured in seston samples from an alder-dominated compared to a coniferous forested stream. Preliminary stable isotope analyses shows that the vegetation and invertebrate shredders from alder sites had higher ¹⁵N content than conifer dominated sites. In addition, the ¹³C signature of invertebrates (grazer, filter feeder, predator, and aggregate samples) from alder streams was higher compared to conifer dominated systems, suggesting differences in invertebrate food source derivation between stream systems.

Ecological role of estuarine large woody debris
supporting juvenile Pacific salmon

Alicia Wick
aliwick@u.washington.edu

Ascribed functions of large woody debris (LWD) in estuaries are to some degree parallel with those described for rivers and streams but not comparably documented; there have been few rigorous tests to establish whether wood is of ecological consequence in estuarine ecosystems. LWD's function as juvenile salmonid habitat is a prime example of extrapolation without substantiation. In some cases, woody debris is explicitly designed into estuarine wetland restoration projects at significant cost without evidence for importance to fish, design criteria, or dynamics. Research is still sparse in testing assumptions of wood's habitat functions in order to develop assessment and restoration criteria and to understand the mechanisms of its interaction in the landscape. This project aims to examine the small-scale ecological function of woody debris in estuarine sloughs by examining fish and invertebrate use, sediment characteristics, and movement of woody debris in oligohaline-brackish estuarine sloughs on the Chehalis River (Grays Harbor, WA).

p o s t e r s
undergraduate student research

Riparian canopy cover and its
effects on stream temperature in eastern Washington

Ashley Adams
ashna@u.washington.edu

Water temperature is very important for the health of an aquatic ecosystem. Temperature influences the amount of dissolved oxygen in the water, the rate of photosynthesis by algae and other aquatic plants, and the metabolic rates, respiration, and stress levels of aquatic organisms. There are many factors that influence the temperature regime of a stream. These include the seasonal and diurnal air temperature, elevation, channel width and depth, topography, groundwater inputs, and shade provided by the riparian vegetation. This project focuses on stream shading and evaluates the impact that various harvesting practices have on temperatures in several eastern Washington streams. Overall, as the percentage of shade decreased on small streams, the average daily maximum temperature increased.

Hyporheic zones in urban, forested, and agricultural Streams

Andrew Bryant
ajbryant@u.washington.edu

The hyporheic zone is the area below the bed of a stream through which stream water exchanges with groundwater. The hyporheic zone has a distinct and important role in stream health and regulation, but because little research has been done regarding human impacts, it is not taken into account in the regulation of urban development. The hyporheic zones of urban, forested, and agricultural streams were studied to evaluate the impacts of development, and to determine if hyporheic zones should be specifically protected from human disturbance.

Streams of the Puget Sound lowlands: Summertime conditions
A stream temperature survey

Andrea Jones
ajj@u.washington.edu

The Center for Urban Water Resources Management at the University of Washington, in cooperation with the Center for Streamside Studies and local storm water agencies, tribes, and citizen groups, have coordinated a regional, one-day intensive stream-temperature monitoring survey that has happened each year at the beginning of August since 1998. Our intention was to characterize the range, distribution, and determinants of summertime high temperatures in fish-bearing (and tributary to fish-bearing) lowland stream systems in the Puget Sound lowlands. We want to characterize these temperatures because cold-water fisheries can be strongly affected by elevated summertime stream temperatures. Watersheds with primarily urban and suburban land uses were surveyed, but we included some rural and forested basins as controls. Over 100 individuals, representing approximately 20 different agencies and community groups, collect over 600 temperature measurements across the south-central Puget Lowland in a two-hour period each year. Some data sites were visited multiple times by different volunteers so that data could be checked for replicability.