The primary economic difficulty that watershed restoration faces is that there are relatively few markets for its products. In economic-speak, this is a market failure in the provision of watershed restoration. Because of this market failure, collective action, often in the form of government intervention, usually occurs in order to pay for restoration activities. Many government programs, and society at large, typically require the benefits of an activity to outweigh its costs. Thus it is important to quantify the economic benefits arising from watershed restoration. Measured by damage caused, willingness to pay, political referenda, averted expenditures, travel costs incurred, and changes in housing values, researchers consistently conclude that watershed restoration has significant economic benefits. Watershed restoration projects have other economic impacts as well, directly and indirectly employing many people, and potentially contributing to the long-term viability and growth of communities. However, restoration advocates face hurdles in justifying restoration on economic grounds due to the vague nature of nonmarket valuation, long timescales required for achieving a positive return on investment in certain restoration projects, and unknown incremental benefits of watershed restoration in increasing the natural amenity qualities of communities.
Journal of the American Water Resources Association
We compared summer stream temperature patterns in 40 small forested watersheds in the Hoh and Clearwater basins in the western Olympic Peninsula, Washington, to examine correlations between previous riparian and basin-wide timber harvest activity and stream temperatures. Seven watersheds were unharvested, while the remaining 33 had between 25% and 100% of the total basin harvested, mostly within the last 40 years. Mean daily maximum temperatures were significantly different between the harvested and unharvested basins, averaging 14.5C and 12.1C, respectively. Diurnal fluctuations between harvested and unharvested basins were also significantly different, averaging 1.7C and 0.9C, respectively. Total basin harvest was correlated with average daily maximum temperature (r2 = 0.39), as was total riparian harvest (r2 = 0.32). The amount of recently clear-cut riparian forest (<20 year) within 600 m upstream of our monitoring sites ranged from 0% to 100% and was not correlated to increased stream temperatures. We used Akaike’s Information Criteria (AIC) analysis to assess whether other physical variables could explain some of the observed variation in stream temperature. We found that variables related to elevation, slope, aspect, and geology explain between 5% and 14% more of the variability relative to the variability explained by percent of basin harvested (BasHarv), and that the BasHarv was consistently a better predictor than the amount of riparian forest harvested. While the BasHarv is in all of the models that perform well, the AIC analysis shows that there are many models with two variables that perform about the same and therefore it would be difficult to choose one as the best model.We conclude that adding additional variables to the model does not change the basic findings that there is a relatively strong relationship between maximum daily stream temperatures and the total amount of harvest in a basin, and strong, but slightly weaker relationship between maximum daily stream temperatures and the total riparian harvest in a basin. Seventeen of the 40 streams exceeded the Washington State Department of Ecology’s (DOE) temperature criterion for waters defined as ‘‘core salmon and trout habitat’’ (class AA waters). The DOE temperature criterion for class AA waters is any seven-day average of daily maximum temperatures in excess of 16C. The probability of a stream exceeding the water quality standard increased with timber harvest activity. All unharvested sites and five of six sites that had 25-50% harvest met DOEs water quality standard.In contrast, only nine of eighteen sites with 50-75% harvest and two of nine sites with >75% harvest met DOEs water quality standard. Many streams with extensive canopy closure, as estimated by the age of riparian trees, still had higher temperatures and greater diurnal fluctuations than the unharvested basins. This suggests that the impact of past forest harvest activities on stream temperatures cannot be entirely mitigated through the reestablishment of riparian buffers.
Michael M. Pollock, Timothy J. Beechie, Martin Liermann, and Richard E. Bigley
Journal of the American Water Resources Association
This paper presents the results of an ex post survey of recreational anglers for the lower Kennebec River, post-Edwards Dam removal. To the best of our knowledge, this study represents one of the first ex post analyses of fisheries restoration from dam removal. We find significant benefits have accrued to anglers using the restored fishery. Specifically, anglers are spending more to visit the fishery, a direct indication of the increased value anglers place on the improved fishery. Anglers are also willing to pay for increased angling opportunities on the river. These findings have policy implications for other privately owned dams that are currently undergoing relicensing and ⁄ or dam removal considerations. Our findings may also hold implications for fisheries that have deteriorated due to historic dam construction.
Habitat unit classification can be a useful descriptive tool in hierarchical stream classification. However, a critical evaluation reveals that it is applied inappropriately when used to quantify aquatic habitat or channel morphology in an attempt to monitor the response of individual streams to human activities. First, due to the subjectivity of the measure, observer bias seriously compromises repeatability, precision, and transferability of the method. Second, important geomorphic and ecological changes in stream habitats are not always manifested as changes in habitat-unit or frequency or characteristics. Third, classification data are nominal, which can intrinsically limit their amenability to statistical analysis. Finally, using the frequency of specific habitat-unit types (e.g. pool/riffle ration or percent pool) as a response variable for stream monitoring commonly leads to the establishment of management thresholds or targets for habitat-unit types. This, in turn, encourages managers to focus on direct manipulation or replacement of habitat structures while neglecting long-term maintenance or re-establishment of habitat-forming biophysical processes. Stream habitat managers and scientists should only use habitat unit classification to descriptively stratify in-stream conditions. They should not use habitat unit classification as a means of quantifying and monitoring aquatic habitat and channel morphology. Monitoring must instead focus on direct, repeatable, cost-efficient, and quantitative measures of selected physical, chemical, and biological components and processes spanning several scales of resolution.