USE OF PEBBLE COUNTS TO EVALUATE FINE SEDIMENT INCREASE IN STREAM CHANNELS1

ABSTRACT: The pebble count, a quick and simple technique for characterizing streambed materials, has long been used by geomorphologists, hydrologists, and river engineers. This paper describes how pebble counts have been used to monitor fine sediment (particles less then 6 mm in size) on the Boise National Forest. Data from two watersheds subjected to major wildfires and the failure of a dam are discussed. Following wildfires, pebble count data showed increases in streambed fines followed by improvement of the stream substrate with time as the watersheds recovered. For the dam failure, pebble count data showed an increase in fines in the stream below the failure and were used to track the distance of sediment movement downstream. Pebble counts may be best used where fine sediment on channel substrates are a concern, such as in granitic watersheds where coarse sands are a large component of bedload and land-disturbing activities introduce fine sediment into streams. Pebble counts are found to be a simple and rapid monitoring method that can be used to help determine whether or not land management activities or land disturbances are introducing fine sediment into streams.     

Adequacy of Visually Classified Particle Count Statistics From Regional Stream Habitat Surveys1

Abstract: Streamlined sampling procedures must be used to achieve a sufficient sample size with limited resources in studies undertaken to evaluate habitat status and potential management‐related habitat degradation at a regional scale. At the same time, these sampling procedures must achieve sufficient precision to answer science and policy‐relevant questions with an acceptable and statistically quantifiable level of uncertainty. In this paper, we examine precision and sources of error in streambed substrate characterization using data from the Environmental Monitoring and Assessment Program (EMAP) of the U.S. Environmental Protection Agency, which uses a modified “pebble count” method in which particle sizes are visually estimated rather than measured. While the coarse (2?) size classes used in EMAP have little effect on the precision of estimated geometric mean (D_gm) or median (D₅₀) particle diameter, variable classification bias among observers can contribute as much as 0.3?, or about 15‐20%, to the root‐mean‐square error (RMSE) of D_gm or D₅₀ estimates. D_gm and D₅₀ estimates based on EMAP data are nearly equal when fine sediments (<2 mm) are excluded, but otherwise can differ by up to a factor of 2 or more, with D_gm < D₅₀ for gravel‐bed streams. The RMSE of reach‐scale particle size estimates based on visually classified particle count data from EMAP surveys, including variability associated with reoccupying unmarked sample reaches during revisits, is up to five to seven times higher than that reported for traditional measured pebble counts by multiple observers at a plot scale. Nonetheless, a variance partitioning analysis shows that the ratio of among site to revisit variance for several EMAP substrate metrics exceeds 8 for many potential regions of interest, suggesting that the data have adequate precision to be useful in regional assessments of channel morphology, habitat quality, or ecological condition.     

VARIABILITY IN MEASURES OF MACROINVERTEBRATE COMMUNITY STRUCTURE BY STREAM REACH AND STREAM CLASS1

ABSTRACT: Macroinvertebrate community data collected from streams in Wyoming were assessed at various scales: within one stream reach, between stream reaches within one stream, between streams, and between stream classes. Fourteen indices including number of individuals/m², biomass/m², number of taxa, Shannon's diversity index, and functional feeding group ratios were used to compare macroinvertebrates by stream reach and stream class. Statistical analysis indicated that for five of the 14 indices, significant variability occurred between macroinvertebrate communities within one reach. For two of the remaining nine indices there was significant variability between communities from several reaches within the same stream. For seven of the nine indices, there was significant variability among macroinvertebrate communities from streams of the same class. Variability among the macroinvertebrate communities from the three stream classes was significantly different for seven of the nine indices. ANOVA results suggest that macroinvertebrate communities from different samples within one reach and between reaches within one stream were more comparable than those from different streams and different stream classes.     

Comparison of Three Pebble Count Protocols (EMAP,PIBO, and SFT) in Two Mountain Gravel‐Bed Streams1

Abstract: Although the term ``pebble count'' is in widespread use, there is no standardized methodology used for the field application of this procedure. Each pebble count analysis is the product of several methodological choices, any of which are capable of influencing the final result. Because there are virtually countless variations on pebble count protocols, the question of how their results differ when applied to the same study reach is becoming increasingly important. This study compared three pebble count protocols: the reach‐averaged Environmental Monitoring and Assessment Program (EMAP) protocol named after the EMAP developed by the Environmental Protection Agency, the habitat‐unit specific U.S. Forest Service’s PACFISH/INFISH Biological Opinion (PIBO) Effectiveness Monitoring Program protocol, and a data‐intensive method developed by the authors named Sampling Frame and Template (SFT). When applied to the same study reaches, particle‐size distributions varied among the three pebble count protocols because of differences in sample locations within a stream reach and along a transect, in particle selection, and particle‐size determination. The EMAP protocol yielded considerably finer, and the PIBO protocol considerably coarser distributions than the SFT protocol in the pool‐riffle study streams, suggesting that the data cannot be used interchangeably. Approximately half of the difference was due to sampling at different areas within the study reach (i.e., wetted width, riffles, and bankfull width) and at different locations within a transect. The other half was attributed to using different methods for particle selection from the bed, particle‐size determination, and the use of wide, nonstandard size classes. Most of the differences in sampling outcomes could be eliminated by using simple field tools, by collecting a larger sample size, and by systematically sampling the entire bankfull channel and all geomorphic units within the reach.     

THE EPIDEMIOLOGY OF MONITORING1

ABSTRACT: An informal sample of 30 flawed monitoring projects was examined to identify the most common problems and to determine how they could have been prevented. Problems fall into two general categories: 70 percent of the sampled projects had design problems, and 50 percent of the sampled projects had procedural problems. Monitoring projects implemented by land‐management agencies tended to have a higher proportion of procedural problems than did university‐based programs (generally graduate student research), while the frequency of design problems was similar between agencies and universities. The most common problems were poorly trained or unmotivated field crews (37 percent of projects, a procedural problem), a sampling plan that was not capable of measuring what was needed to meet project objectives (30 percent, design), delays in analyzing data (27 percent, procedure), inadequate monitoring durations (27 percent, design), and absence of the collateral information needed to interpret results (20 percent, procedure). Most of the problems could have been avoided by submission of the study design to thorough technical and statistical review, active participation of the principal investigators in field data collection, and analysis of at least some of the data as soon as information was collected so that problems could be recognized early enough to be corrected.     

PRECISION OF CHANNEL WIDTH AND POOL AREA MEASUREMENTS1

ABSTRACT: The precision of width and pool area measurements has rarely been considered in relation to downstream or at section hydraulic geometry, fisheries studies, long-term or along a continuum research studies, or agency monitoring techniques. We assessed this precision and related it to other stream morphologic characteristics. Confidence limits (95 percent) around mean estimates with four transects (cross-sections perpendicular to the channel center-line) ranged from ± 0.4 to 1.8 m on streams with a width of only 2.2 m. To avoid autocorrelation, transects should be spaced about three channel widths apart. To avoid stochastic inhomogeneity, reach length should be about 30 channel widths or ten transects to optimize sampling efficiency. Precision of width measurements decreased with decreased depth and increased with stream size. Both observations reflect variability caused by features such as boulders or coarse woody debris. Pool area precision increased with pool area reflecting increased precision for flat, wide streams with regular pool-rime sequences. The least precision occurred on small, steep streams with random, boulder or coarse woody debris formed pools.     

AN EVALUATION OF PHYSICAL STREAM HABITAT ATTRIBUTES USED TO MONITOR STREAMS1

ABSTRACT: The last few decades have seen an increased reliance on the use of stream attributes to monitor stream conditions. The use of stream attributes has been criticized because of variation in how observers evaluate them, inconsistent protocol application, lack of consistent training, and the difficulty in using them to detect change caused by management activity. In this paper, we evaluate the effect of environmental heterogeneity and observer variation on the use of physical stream attributes as monitoring tools. For most stream habitat attributes evaluated, difference among streams accounted for greater than 80 percent of the total survey variation. To minimize the effect that variation among streams has on evaluating stream conditions, it may be necessary to design survey protocols and analysis that include stratification, permanent sites, and/or analysis of covariance. Although total variation was primarily due to differences among streams, observers also differed in their evaluation of stream attributes. This study suggests that if trained observers conducting a study that is designed to account for environmental heterogeneity can objectively evaluate defined stream attributes, results should prove valuable in monitoring differences in reach scale stream conditions. The failure to address any of these factors will likely lead to the failure of stream attributes as effective monitoring tools.     

The Role of Observer Variation in Determining Rosgen Stream Types in Northeastern Oregon Mountain Streams1

Abstract: Consistency in determining Rosgen stream types was evaluated in 12 streams within the John Day Basin, northeastern Oregon. The Rosgen classification system is commonly used in the western United States and is based on the measurement of five stream attributes: entrenchment ratio, width‐to‐depth ratio, sinuosity, slope, and substrate size. Streams were classified from measurements made by three monitoring groups, with each group fielding multiple crews that conducted two to three independent surveys of each stream. In only four streams (33%) did measurements from all crews in all monitoring groups yield the same stream type. Most differences found among field crews and monitoring groups could be attributed to differences in estimates of the entrenchment ratio. Differences in entrenchment ratio were likely due to small discrepancies in determination of maximum bankfull depth, leading to potentially large differences in determination of Rosgen’s flood‐prone width and consequent values of entrenchment. The result was considerable measurement variability among crews within a monitoring group, and because entrenchment ratio is the first discriminator in the Rosgen classification, differences in the assessment of this value often resulted in different determination of primary stream types. In contrast, we found that consistently evaluated attributes, such as channel slope, rarely resulted in any differences in classification. We also found that the Rosgen method can yield nonunique solutions (multiple channel types), with no clear guidance for resolving these situations, and we found that some assigned stream types did not match the appearance of the evaluated stream. Based on these observations we caution the use of Rosgen stream classes for communicating conditions of a single stream or as strata when analyzing many streams due to the reliance of the Rosgen approach on bankfull estimates which are inherently uncertain.     

MASS LOAD ESTIMATION ERRORS UTILIZING GRAB SAMPLING STRATEGIES IN A KARST WATERSHED1

ABSTRACT: Developing a mass load estimation method appropriate for a given stream and constituent is difficult due to inconsistencies in hydrologic and constituent characteristics. The difficulty may be increased in flashy flow conditions such as karst. Many projects undertaken are constrained by budget and manpower and do not have the luxury of sophisticated sampling strategies. The objectives of this study were to: (1) examine two grab sampling strategies with varying sampling intervals and determine the error in mass load estimates, and (2) determine the error that can be expected when a grab sample is collected at a time of day when the diurnal variation is most divergent from the daily mean. Results show grab sampling with continuous flow to be a viable data collection method for estimating mass load in the study watershed. Comparing weekly, biweekly, and monthly grab sampling, monthly sampling produces the best results with this method. However, the time of day the sample is collected is important. Failure to account for diurnal variability when collecting a grab sample may produce unacceptable error in mass load estimates. The best time to collect a sample is when the diurnal cycle is nearest the daily mean.     

REGIONAL CHARACTERISTICS OF NUTRIENT CONCENTRATIONS IN STREAMS AND THEIR APPLICATION TO NUTRIENT CRITERIA DEVELOPMENT1

ABSTRACT: In order to establish meaningful nutrient criteria, consideration must be given to the spatial variations in geographic phenomena that cause or reflect differences in nutrient concentrations in streams. Regional differences in stream nutrient concentrations were illustrated using stream data collected from 928 nonpoint‐source watersheds distributed throughout the country and sampled as part of the U.S. EPA National Eutrophication Survey (NES). Spatial patterns in the differences were compared and found to correspond with an a priori regional classification system based on regional patterns in landscape attributes associated with variation in nutrient concentrations. The classification consists of 14 regions composed of aggregations of the 84 U.S. EPA Level III Ecoregions. The primary distinguishing characteristics of each region and the factors associated with variability in water quality characteristics are presented. The use of the NES and many other extant monitoring data sets to develop regional reference conditions for nutrient concentrations in streams is discouraged on the basis of sample representation. The necessity that all sites used in such an effort be regionally representative and consistently screened for least possible impact is emphasized. These sampling issues are rigorously addressed by the U.S. EPA Environmental Monitoring and Assessment Program (EMAP). A case‐study, using EMAP data collected from the Central and Eastern Forested Uplands, demonstrates how regional reference conditions and draft nutrient criteria could be developed.     

EFFECTIVENESS OF BIOPHYSICAL CRITERIA IN THE HIERARCHICAL CLASSIFICATION OF DRMNAGE BASINS1

ABSTRACT: A subwatershed base map of 84 hydrologic subregions within the Columbia River Basin (approximately 58,361,000 ha) was developed following hierarchical principles of ecological unit mapping. Our primary objectives were to inspect the relations between direct and indirect biophysical variables in the prediction of valley bottom and stream type patterns, and to identify hydrologic subregions (based on these results) that had similar aquatic patterns for which consistent management practices could be applied. Realization of these objectives required: (1) stratified subsampling of valley bottom and stream type composition within selected sub‐watersheds, (2) identification of direct and indirect biophysical variables that were mappable across the basin and that exerted primary control on the distribution of sampled aquatic patterns, and (3) development of hydrologic subregion maps based on the primary biophysical variables identified. Canonical correspondence analysis indicated that a core set of 15 direct variables (e.g., average watershed slope, drainage density, ten‐year peak flow) and 19 indirect variables (i.e., nine subsection groups, four lithology groups, and six potential vegetation settings) accounted for 31 and 30 percent (respectively) of valley bottom/stream type composition variability and 84 and 80 percent (respectively) of valley bottom/stream type environmental variability within subsamples. The 19 indirect biophysical variables identified were used to produce an ecological unit classification of 7,462 subwatersheds within the basin by a hierarchical agglomerative clustering technique (i.e., hydrologic subregions were identified). Discriminant analysis indicated that 13 direct biophysical variables could correctly assign 80 percent of the subwatersheds to their indirect biophysical classification, thus demonstrating the strong relation that exists between indirect biophysical based classifications (ecological units) and the direct biophysical variables that determine finer‐level aquatic patterns. Our hydrologic subregion classifications were also effective in explaining observed differences in management hazard ratings across all subwatersheds of the basin. Results of this research indicate that ecological units can be effectively used to produce watershed classifications that integrate the effects of direct biophysical variables on finer‐level aquatic patterns, and predict opportunities and limitations for management.     

Compensatory Stream and Wetland Mitigation in North Carolina: An Evaluation of Regulatory Success

Data from a probability sample were used to estimate wetland and stream mitigation success from 2007 to 2009 across North Carolina (NC). “Success” was defined as whether the mitigation site met regulatory requirements in place at the time of construction. Analytical results were weighted by both component counts and mitigation size. Overall mitigation success (including preservation) was estimated at 74 % (SE = 3 %) for wetlands and 75 % (SE = 4 %) for streams in NC. Compared to the results of previous studies, wetland mitigation success rates had increased since the mid-1990s. Differences between mitigation providers (mitigation banks, NC Ecosystem Enhancement Program’s design-bid-build and full-delivery programs, NC Department of Transportation and private permittee-responsible mitigation) were generally not significant although permittee-responsible mitigation yielded higher success rates in certain circumstances. Both wetland and stream preservation showed high rates of success and the stream enhancement success rate was significantly higher than that of stream restoration. Additional statistically significant differences when mitigation size was considered included: (1) the Piedmont yielded a lower stream mitigation success rate than other areas of the state, and (2) recently constructed wetland mitigation projects demonstrated a lower success rate than those built prior to 2002. Opportunities for improvement exist in the areas of regulatory record-keeping, understanding the relationship between post-construction establishment and long-term ecological trajectories of stream and wetland restoration projects, incorporation of numeric ecological metrics into mitigation monitoring and success criteria, and adaptation of stream mitigation designs to achieve greater success in the Piedmont.     

Flood Effects on an Alaskan Stream Restoration Project: The Value of Long‐Term Monitoring1

Densmore, Roseann V. and Kenneth F. Karle, 2009. Flood Effects on an Alaskan Stream Restoration Project: The Value of Long‐Term Monitoring. Journal of the American Water Resources Association (JAWRA) 45(6):1424‐1433. Abstract: On a nationwide basis, few stream restoration projects have long‐term programs in place to monitor the effects of floods on channel and floodplain configuration and floodplain vegetation, but long‐term and event‐based monitoring is required to measure the effects of these stochastic events and to use the knowledge for adaptive management and the design of future projects. This paper describes a long‐term monitoring effort (15 years) on a stream restoration project in Glen Creek in Denali National Park and Preserve in Alaska. The stream channel and floodplain of Glen Creek had been severely degraded over a period of 80 years by placer mining for gold, which left many reaches with unstable and incised streambeds without functioning vegetated floodplains. The objectives of the original project, initiated in 1991, were to develop and test methods for the hydraulic design of channel and floodplain morphology and for floodplain stabilization and riparian habitat recovery, and to conduct research and monitoring to provide information for future projects in similar degraded watersheds. Monitoring methods included surveyed stream cross‐sections, vegetation plots, and aerial, ground, and satellite photos. In this paper we address the immediate and outlying effects of a 25‐year flood on the stream and floodplain geometry and riparian vegetation. The long‐term monitoring revealed that significant channel widening occurred following the flood, likely caused by excessive upstream sediment loading and the fairly slow development of floodplain vegetation in this climate. Our results illustrated design flaws, particularly in regard to identification and analysis of sediment sources and the dominant processes of channel adjustment.     

DIAGNOSTIC APPROACH TO STREAM CHANNEL ASSESSMENT AND MONITORING1

ABSTRACT: We suggest that a diagnostic procedure, not unlike that followed in medical practice, provides a logical basis for stream channel assessment and monitoring. Our argument is based on the observation that a particular indicator or measurement of stream channel condition can mean different things depending upon the local geomorphic context and history of the channel in question. This paper offers a conceptual framework for diagnosing channel condition, evaluating channel response, and developing channel monitoring programs. The proposed diagnostic framework assesses reach‐level channel conditions as a function of location in the channel network, regional and local biogeomorphic context, controlling influences such as sediment supply and transport capacity, riparian vegetation, the supply of in‐channel flow obstructions, and disturbance history. Field assessments of key valley bottom and active channel characteristics are needed to formulate an accurate diagnosis of channel conditions. A similar approach and level of understanding is needed to design effective monitoring programs, as stream type and channel state greatly affect the type and magnitude of channel response to changes in discharge and sediment loads. General predictions are made for five channel types with respect to the response of various stream characteristics to an increase in coarse sediment inputs, fine sediment inputs, and the size and frequency of peak flows, respectively. These predictions provide general hypotheses and guidance for channel assessment and monitoring. However, the formulation of specific diagnostic criteria and monitoring protocols must be tailored to specific geographic areas because of the variability in the controls on channel condition within river basins and between regions. The diagnostic approach to channel assessment and monitoring requires a relatively high level of training and experience, but proper application should result in useful interpretation of channel conditions and response potential.     

REMOTE SENSING OF RIPARIAN BUFFERS: PAST PROGRESS AND FUTURE PROSPECTS1

Riparian buffer zone management is an area of increasing relevance as human modification of the landscape continues unabated. Land and water resource managers are continually challenged to maintain stream ecosystem integrity and water quality in the context of rapidly changing land use, which often offsets management gains. Approaches are needed not only to map vegetation cover in riparian zones, but also to monitor the changes taking place, target restoration activities, and assess the success of previous management actions. To date, these objectives have been difficult to meet using traditional techniques based on aerial photos and field visits, particularly over large areas. Recent advances in remote sensing have the potential to substantially aid buffer zone management. Very high resolution imagery is now available that allows detailed mapping and monitoring of buffer zone vegetation and provides a basis for consistent assessments using moderately high resolution remote sensing (e.g., Landsat). Laser‐based remote sensing is another advance that permits even more detailed information on buffer zone properties, such as refined topographic derivatives and multidimensional vegetation structure. These sources of image data and map information are reviewed in this paper, examples of their application to riparian buffer mapping and stream health assessment are provided, and future prospects for improved buffer monitoring are discussed.     

REGIONAL SCALE TREND MONITORING OF INDICATORS OF TROPHIC CONDITION OF LAKES1

ABSTRACT: The U.S. Environmental Protection Agency has proposed a sample survey design to answer questions about the ecological condition and trends in condition of U.S. ecological resources. To meet the objectives, the design relies on a probability sample of the resource population of interest (e.g., a random sample of lakes) each year on which measurements are made during an index period. Natural spatial and temporal variability and variability in the sampling process all affect the ability to describe the status of a population and the sensitivity for trend detection. We describe the important components of variance and estimate their magnitude for indicators of trophic condition of lakes to illustrate the process. We also describe models for trend detection and use them to demonstrate the sensitivity of the proposed design to detect trends. If the variance structure that develops during the probability surveys is like that synthesized from available databases and the literature, then the trends in common indicators of trophic condition of the specified magnitude should be detectable within about a decade for Secchi disk transparency (0.5–1 percentiyear) and total phosphorus (2–3 percent/year), but not for chlorophyll-a (> 3–4 percent/year), which will take longer.     

A Comparison of Protocols and Observer Precision for Measuring Physical Stream Attributes1

Abstract: Stream monitoring programs commonly measure physical attributes to assess the effect of land management on stream habitat. Variability associated with the measurement of these attributes has been linked to a number of factors, but few studies have evaluated variability due to differences in protocols. We compared six protocols, five used by the U.S. Department of Agriculture Forest Service and one by the U.S. Environmental Protection Agency, on six streams in Oregon and Idaho to determine whether differences in protocol affect values for 10 physical stream attributes. Results from Oregon and Idaho were combined for groups participating in both states, with significant differences in attribute means for 9 out of the 10 stream attributes. Significant differences occurred in 5 of 10 in Idaho, and 10 of 10 in Oregon. Coefficients of variation, signal‐to‐noise ratio, and root mean square error were used to evaluate measurement precision. There were differences among protocols for all attributes when states were analyzed separately and as a combined dataset. Measurement differences were influenced by choice of instruments, measurement method, measurement location, attribute definitions, and training approach. Comparison of data gathered by observers using different protocols will be difficult unless a core set of protocols for commonly measured stream attributes can be standardized among monitoring programs.     

AQUATIC TRANSPORT OF HEAVY METALS IN THE URBAN ENVIRONMENT1

ABSTRACT: A study has been conducted for the past two years on a 4.6 mile stretch of the Saddle River near Lodi, New Jersey. The primary objectives of this study were two fold; initially, the amounts of various heavy metals being contributed to the Saddle River by stormwater runoff, rainfall, and individual tributaries, etc., were investigated to better delineate the distribution of various sources of heavy metals to the aquatic environment. Secondly, a series of benthal deposits from the Saddle River were analyzed to determine the fate of these metals once introduced into the receiving stream. A mass balance analysis of heavy metals in the Saddle River was performed to determine the amount of these materials contributed from unrecorded sources. The results of this study seemed to demonstrate the importance of considering the potential scouring of river sediments as a secondary source of metals in determinations of this type. The distribution of metals in precipitation samples collected in this study was found to be similar to that in runoff, with lead and zinc predominating. Relative concentrations of metals in precipitation as compared to those of stormwater were relatively insignificant. Metal concentrations of bottom sediments were found to vary considerably from sample to sample.     

Assessment of Changes in Stream and Riparian Conditions of the Marys River Basin,Nevada1

Abstract: Stream and riparian managers must effectively allocate limited financial and personnel resources to monitor and manage riparian ecosystems. They need to use management strategies and monitoring methods that are compatible with their objectives and the response potential of each stream reach. Our objective is to help others set realistic management objectives by comparing results from different methods used to document riparian recovery across a diversity of stream types. The Bureau of Land Management Elko Field Office, Nevada, used stream survey, riparian proper functioning condition (PFC) assessment, repeat photographic analysis, and stream and ecological classification to study 10 streams within the Marys River watershed of northeast Nevada during all or parts of 20 years. Most riparian areas improved significantly from 1979 to 1992‐1993 and then additionally by 1997‐2000. Improvements were observed in riparian and habitat condition indices, bank cover, and stability, pool quality, bank angle, and depth of undercut bank. Interpretation of repeat photography generally confirmed results from stream survey and should be part of long‐term riparian monitoring. More attributes of Rosgen stream types C and E improved than of types B and F. A and Gc streams did not show significant improvement. Alluvial draws and alluvial valleys improved in more ways than V‐erosional canyons and especially V‐depositional canyons. Stream survey data could not be substituted for riparian PFC assessment. Riparian PFC assessments help interpret other data.     

Describing Damage to Stream Modification Projects in Constrained Settings

Complex relationships between stream functions and processes make evaluation of stream modification projects difficult. Informed by vague objectives and minimal monitoring data, post‐construction project evaluations can often be a subjective attribution of success or failure. This article provides a simple framework to rapidly describe the degree of damage in stream modification projects performed in constrained settings. Based on widely accepted evaluations of physical habitat quality and stream stability, the damage states framework describes a continuum of damage in multiple categories that relate natural stream functions to the often desired state of static equilibrium. Given that channel form is closely related to stream function, it follows that changes to the channel form result in changes in function. The damage states focus on damage to flow hydraulics, sediment transport and channel equilibrium, hydraulic, and geomorphic parameters that describe basic stream functioning and support higher level functions in the modified channel. The damage states can be used in decision making as a systematic method to determine the need for repair and design adjustments.