Mancos Watershed Functional Assessment

Home Browse Search

processes of erosion and deposition along that reach are in relative equilibrium. Thus, when interpreting the surveys, the results of all indicators should be considered together. This will facilitate deciding which parts of the ecosystem within the study reach may be most out of balance with natural processes, and therefore which of those parts may be the most important or the most suitable for future restoration efforts. Second, in order to increase the number of survey sites that can be sampled, the protocol uses variables that can be measured rapidly in the field and that do not require specialized equipment. More detailed and extensive methods have been developed for several of the individual indicators included in this protocol. Many of these analyses may take one or more days to complete, just for that single variable. However, should any of the individual components of the reach be found to be particularly problematic or non-functional using the RSRA protocol, then the more specialized methods can be used during subsequent visits to the site in order to collect additional quantitative information on that particular variable. Third, the RSRA protocol measures only the current condition of the ecosystem. It does not base its scores upon some hypothesized future state or successional trend within the reach, as is done with several other riparian assessment methods (e.g., the BLM’s Proper Functioning Condition assessment). The RSRA method addresses the ability of the ecosystem to provide some important function at the present time, and not whether it would be likely to do so at some point in the future, if current trends or management practices on the reach continue. This approach is used because stream-riparian systems are highly dynamic and they are often subject to disturbances (e.g., large floods) that can alter successional trends and make predictions of future conditions on an individual reach highly problematic. By evaluating only current conditions, this protocol can be used as a powerful tool for monitoring and measuring future changes in the functional status of the system. For example, if a reach is rated as in poor condition with respect to a particular set of parameters, reevaluating the system using the identical protocol in subsequent years gives one the ability to measure the effectiveness of any management change or active restoration program and to undertake corrections if the restoration actions are found to be not producing the desired changes. This type of adaptive management approach can be extremely difficult if the evaluation and monitoring measures are based primarily upon the expectations of some future, rather than current, condition. Fourth, the protocol incorporates a quantitative, five level, scale in order to assign a score to each of the variables examined. Many of the other riparian assessment systems are based upon dichotomous categories, such as "functional/non-functional", or "yes/no", and they can be subjective and difficult to repeat in the same way from one year to the next, or when conducted by different observers. In addition, dichotomous scoring systems often are not able to provide sufficient insight into the ecological processes that may be affecting the ability of the system to provide (or not provide) desired functions that would indicate whether active restoration efforts might be necessary. The RSRA scoring levels were based upon a review of existing assessment and monitoring protocols, extensive external peer-reviews, and the individual research experiences of all of the authors. A scale is used for each variable. While individual variables during a survey may receive extreme scores of “1" or “5", it is highly unlikely that all of the scores for a functional category, or that the overall mean score for a particular reach, will receive these outermost ratings. It is therefore important when interpreting the results of the RSRA surveys that all scores be viewed together. For example, most of the scores in one functional category (e.g., fish and aquatic habitat) may be high, but one other variable may be low. In terms of restoration planning, this means that a relatively simple action to correct that one deficiency in the system could have large future impacts. Such actions would then be high priority, since the cost to benefit ratio would be high. Alternatively, low scores in some categories may be difficult to correct without extensive 15