Linking Hydrologic Alteration to Biological Impairment in Urbanizing Streams of the Puget Lowland,Washington, USA1

Abstract: We used a retrospective approach to identify hydrologic metrics with the greatest potential for ecological relevance for use as resource management tools (i.e., hydrologic indicators) in rapidly urbanizing basins of the Puget Lowland. We proposed four criteria for identifying useful hydrologic indicators: (1) sensitive to urbanization consistent with expected hydrologic response, (2) demonstrate statistically significant trends in urbanizing basins (and not in undeveloped basins), (3) be correlated with measures of biological response to urbanization, and (4) be relatively insensitive to potentially confounding variables like basin area. Data utilized in the analysis included gauged flow and benthic macroinvertebrate data collected at 16 locations in 11 King County stream basins. Fifteen hydrologic metrics were calculated from daily average flow data and the Pacific Northwest Benthic Index of Biological Integrity (B‐IBI) was used to represent the gradient of response of stream macroinvertebrates to urbanization. Urbanization was represented by percent Total Impervious Area (%TIA) and percent urban land cover (%Urban). We found eight hydrologic metrics that were significantly correlated with B‐IBI scores (Low Pulse Count and Duration; High Pulse Count, Duration, and Range; Flow Reversals, T_Qmean, and R‐B Index). Although there appeared to be a great deal of redundancy among these metrics with respect to their response to urbanization, only two of the metrics tested – High Pulse Count and High Pulse Range – best met all four criteria we established for selecting hydrologic indicators. The increase in these high pulse metrics with respect to urbanization is the result of an increase in winter high pulses and the occurrence of high pulse events during summer (increasing the frequency and range of high pulses), when practically none would have occurred prior to development. We performed an initial evaluation of the usefulness of our hydrologic indicators by calculating and comparing hydrologic metrics derived from continuous hydrologic simulations of selected basin management alternatives for Miller Creek, one of the most highly urbanized basins used in our study. We found that the preferred basin management alternative appeared to be effective in restoring some flow metrics close to simulated fully forested conditions (e.g., T_Qmean), but less effective in restoring other metrics such as High Pulse Count and Range. If future research continues to support our hypothesis that the flow regime, particularly High Pulse Count and Range, is an important control of biotic integrity in Puget Lowland streams, it would have significant implications for stormwater management.     

The new gold rush: fueling ethanol production while protecting water quality

Renewable fuel production, particularly grain-based ethanol, is expanding rapidly in the USA. Although subsidized grain-based ethanol may provide a competitively priced transportation fuel, concerns exist about potential environmental impacts. This contribution focuses on potential water quality implications of expanded grain-based ethanol production and potential impacts of perennial-grass-based cellulosic ethanol. Expanded grain-based ethanol will increase and intensify corn production. Even with recommended fertilizer and land conservation measures, corn acreage can be a major source of N loss to water (20-40 kg ha(-1) yr(-1)). A greater acreage of corn is estimated to increase N and P loss to water by 37% (117 million kg) and 25% (9 million kg), respectively, and measures to encourage adoption of conservation practices are essential to mitigate water quality impairments. Dried distiller's grains remaining after ethanol production from corn grain are used as animal feed and can increase manure P content and may increase N content. Cellulosic fuel-stocks from perennials such as switchgrass and woody materials have the potential to produce ethanol. Although production, storage, and handling of cellulosic materials and conversion technology are limitations, accelerating development of cellulosic ethanol has the potential to reduce dependence on grain fuel-stocks and provide water quality and other environmental benefits. All alternative fuel production technologies could have environmental impacts. There is a need to understand these impacts to help guide policy and help make programmatic and scientific decisions that avoid or mitigate unintended environmental consequences of biofuel production.     

Assessing PAH and PCB emissions from the relocation of harbour sediments using equilibrium passive samplers

Large-scale dredging of contaminated sediments is taking place in the harbor of Oslo, Norway. The dredged sediment masses are transferred into a confined aquatic disposal facility (CAD) in a natural 70-m deep basin within the Oslofjord. Currently there is no established method to determine how much dissolved contaminants are released during relocation and deposition of these sediments. For this reason we tested the use of equilibrium passive samplers consisting of 55 microm thin polyoxymethylene (POM-55) for studying the release of freely dissolved and thus bioavailable PAHs and PCBs at the disposal site, and found this to be a suitable method. In order to use POM-55 for monitoring PCBs, it was necessary to measure their POM-55/water partition coefficients, which was also presented as part of this study. Elevated turbidity (average 4.1 mg l(-1)) was observed at one side of the basin where no natural sill exists. Analysis of POM-55 at this location before and after deposition revealed that there was an increase in freely dissolved concentrations (C(W,free)) during deposition by a factor 37.5 for PAHs and a factor of 2.9 for PCBs. In addition, during deposition phenanthrene-to-anthracene aqueous concentration ratios at this location (values of 3-4) were more similar to those of the deposited sediments (approximately 2) than to those of the CAD water prior to deposition (approximately 14). This was not observed for the other locations where a natural sill exists at approximately 30 m water depth. The POM-55 equilibrium passive samplers are here shown to be useful tools for measuring and understanding the dynamics involved in the release of dissolved contaminants during sediment relocation.     

Land cover dynamics in the Simien Mountains (Ethiopia), half a century after establishment of the National Park

Regional Environmental Change - The Simien Mountains house several endangered and endemic wildlife species and provide important ecosystem services. Despite its regional environmental importance,...     

Effects of preference heterogeneity among landowners on spatial conservation prioritization

The participation of private landowners in conservation is crucial to efficient biodiversity conservation. This is especially the case in settings where the share of private ownership is large and the economic costs associated with land acquisition are high. We used probit regression analysis and historical participation data to examine the likelihood of participation of Danish forest owners in a voluntary conservation program. We used the results to spatially predict the likelihood of participation of all forest owners in Denmark. We merged spatial data on the presence of forest, cadastral information on participation contracts, and individual‐level socioeconomic information about the forest owners and their households. We included predicted participation in a probability model for species survival. Uninformed and informed (included land owner characteristics) models were then incorporated into a spatial prioritization for conservation of unmanaged forests. The choice models are based on sociodemographic data on the entire population of Danish forest owners and historical data on their participation in conservation schemes. Inclusion in the model of information on private landowners’ willingness to supply land for conservation yielded at intermediate budget levels up to 30% more expected species coverage than the uninformed prioritization scheme. Our landowner‐choice model provides an example of moving toward more implementable conservation planning.     

A Shift Toward Building with Nature in the Dredging and Port Development Industries: Managerial Implications for Projects in or Near Natura 2000 Areas

Building with Nature is a new approach to designing water infrastructure, one that seeks to realize socioeconomic project goals in harmony with the environment. The Dutch dredging industry is promoting its application in the Netherlands, but similar concepts are emerging internationally. The Working with Nature concept has been developed under the auspices of the World Association for Waterborne Transport Infrastructure, Engineering with Nature by the US Army Corps of Engineers, and Flanders Bays 2100 by a group of Belgian dredging companies and international consultants. The research discussed in this article focuses on the feasibility of implementing the Building with Nature approach in the context of EU Natura 2000 governance. The initial expectation of the industry was that Natura 2000 regulations would obstruct innovative Building with Nature attempts. The empirical evidence points to a shift toward Building with Nature have taken place on the governance and project levels, and the goals of Natura 2000 and Building with Nature converging in practice. Using specific project-level variables identified by researchers, guidance for project development in Natura 2000 areas was proposed. We conclude by discussing the implications of the research results for the dredging industry dealing with Natura 2000 regulations in Europe and similar overarching nature regulations elsewhere.     

Pregnancy outcome after transcervical cvs with a flexible biopsy forceps: Evaluation of risk factors

The pregnancy outcome of 1936 women who had transcervical chorionic villus sampling (CVS) with a flexible biopsy forceps was evaluated. Follow-up until 4 weeks after delivery was 99.4 per cent. Various patient- and procedure-related risk factors for spontaneous loss (fetal or neonatal death) were analysed using stepwise logistic regression analysis. The overall spontaneous loss rate was 4.5 per cent. Factors found to be significantly associated with spontaneous loss were quantity of villi ≤ 15 mg (relative risk (RR) 2.13), a history of first-trimester miscarriage (RR 1.87) or delivery between 16 and 27 weeks (RR 3.87), cervical culture positive for anaerobes (RR 4.52) or group B streptococcus (RR 3.62), post-procedural bleeding >3 days (RR 1.99), and multiple insertions (RR 2.64). Significant differences in loss rates between individual operators were found. A learning effect was not present. There were no infants born with terminal transversal limb anomalies in our series.