Improvements in Fluvial Stability Associated with Two‐Stage Ditch Construction in Mower County,Minnesota

Water quality and stream habitat in agricultural watersheds are under greater scrutiny as hydrologic pathways are altered to increase crop production. Agricultural drainage ditches function to remove water quickly from farmed landscapes. Conventional ditch designs lack the form and function of natural stream systems and tend to be unstable and provide inadequate habitat. In October of 2009, 1.89 km of a conventional drainage ditch in Mower County, Minnesota, was converted to an alternative system with a two‐stage channel to investigate the improvements in water quality, stability, and habitat. Longitudinal surveys show a 12‐fold increase in the pool‐riffle formation. Cross‐sectional surveys show an average increase in bankfull width of approximately 10% and may be associated to an increased frequency in large storm events. The average increase in bankfull depth was estimated as 18% but is largely influenced by pool formation. Rosgen Stability Analyses show the channel to be highly stable and the banks at a low risk of erosion. The average bankfull recurrence interval was estimated to be approximately 0.30 years. Overall, the two‐stage ditch design demonstrates an increase in fluvial stability, creating a more consistent sediment budget, and increasing the frequency of important instream habitat features, making this best management practice a viable option for addressing issues of erosion, sediment imbalance, and poor habitat in agricultural drainage systems.     

The impact of the congestion charging scheme on ambient air pollution concentrations in London

On 17th February 2003, a congestion charging scheme (CCS), operating Monday–Friday, 07:00–18:00, was introduced in central London along with a programme of traffic management measures. We investigated the potential impact of the introduction of the CCS on measured pollutant concentrations (oxides of nitrogen (NO_X, NO and NO₂), particles with a median diameter less than 10 microns (PM₁₀), carbon monoxide (CO) and ozone (O₃)) measured at roadside and background monitoring sites across Greater London. Temporal changes in pollution concentrations within the congestion charging zone were compared to changes, over the same time period, at monitors unlikely to be affected by the CCS (the control zone) and in the boundary zone between the two. Similar analyses were done for CCS hours during weekends (when the CCS was not operating).Based on the single roadside monitor with the CCS Zone, it was not possible to identify any relative changes in pollution concentrations associated with the introduction of the scheme. However, using background monitors, there was good evidence for a decrease in NO and increases in NO₂ and O₃ relative to the control zone. There was little change in background concentrations of NO_X. There was also evidence of relative reductions in PM₁₀ and CO. Similar changes were observed during the same hours in weekends when the scheme was not operating.The causal attribution of these changes to the CCS per se is not appropriate since the scheme was introduced concurrently with other traffic and emissions interventions which might have had a more concentrated effect in central London. This study provides important pointers for study design and data requirements for the evaluation of similar schemes in terms of air quality. It also shows that results may be unexpected and that the overall effect on toxicity may not be entirely favourable.     

Agricultural pesticide residues in farm ditches of the Lower Fraser Valley, British Columbia, Canada

Transient and permanent farm ditches flowing to the Lower Fraser River tributary fish streams of British Columbia, Canada, were sampled at several locations in 2003-2004 to determine the occurrence and concentration of residues of selected pesticides, their transformation products, and soluble/extractable Cu++ ions. Of the 43 compounds analyzed, 28 and 22 pesticides were detected in transient farm ditch water and sediments, respectively. About 34% fewer pesticides, however, were found in both matrices of permanent farm ditches. Average concentrations (microg L(-1)) of those most frequently detected in permanent farm ditch water were atrazine (0.20), alpha -chlordane (0.06), desethylatrazine (0.13), diazinon (0.55), dieldrin (0.28), endosulfan sulfate (0.16), glyphosate (6), metalaxyl (0.27); and soluble Cu++ ions (25). Those most often found in ditch sediments (microg kg(-1)) were aminomethylphosphonic acid (AMPA) (2,300), 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane (DDT) (250), endosulfan sulfate (500), glyphosate (1,225); and extractable Cu++ ions (58,000). The risk potential of these pesticide residues to non-target aquatic organisms inhabiting Fraser River tributary fish streams contiguous to permanent farm ditches is evaluated and discussed.     

Effect of specimen planar area on electromagnetic flanging

The specimen parameter that is often mentioned with respect to the ability to achieve electromagnetic forming (EMF) is the specimen thickness. If the skin depth is small compared to this parameter, efficient forming will be achieved. However, another parameter that may affect the ability to achieve efficient forming is the specimen's planar area, i.e., the length and width of the specimen. This would particularly become an important factor if EMF is used to fabricate meso/microscale components. In this research, a flat spiral coil was used to flange 0.508 mm thickness, CuZn30 specimens of varying widths (i.e., 10, 14, 18, 22, 35, and 47 mm). These widths were varied in order to modify the projected area of the coil over the specimen. Results showed that a decrease in the specimen width was generally associated with a decrease in forming (i.e., lower flanging angle) due to edge effects in induced eddy currents. Since the magnetic field distribution from the flat spiral coil is asymmetric, material was overhung on both sides of the die. This yielded an extra half turn on the left side of the specimen, and increased forming. The die was also translated to assess differences in flanging generated. In order to achieve meso/microforming with EMF, attention to the interaction between coil design and specimen dimensions is required.     

Shortfalls in minerals investments

The international minerals industry continues to have a substantial investment shortfall. The widening exploration and mineral development gaps, not only in the lesser developed countries but also in the developed nations, are sowing the seeds for future mineral supply disruptions and conflicts. Mutuality of interests demands concerted initiatives, individual as well as collective, to reverse the investment trends established by international mineral finance and the multinational corporations in order to pave the way for secure mineral supplies in the future at acceptable prices.     

Establishing the Canadian Community Monitoring Network

Community-based ecosystem monitoring activities in Canada are increasing in response to a number of factors including: (i) the needs of decision-makers for timely information on local environmental changes; (ii) limited use of government monitoring data and information by decision makers; (iii) government cuts to monitoring programs; (iv) the increasingly recognized need to include stakeholders in planning and management processes; and (v) the desire of citizens to contribute to environmental protection. To date there has been no network coordination of community based monitoring in Canada. This paper reports on the establishment of the Canadian Community Monitoring Network by Environment Canada's Ecological Monitoring and Assessment Network Coordinating Office and the Canadian Nature Federation. Information on research prepared in support of network establishment is presented along with a discussion of the potential of the network.     

Watershed Management and Organizational Dynamics: Nationwide Findings and Regional Variation

Recent attention has focused on resource management initiatives at the watershed scale with emphasis on collaborative, locally driven, and decentralized institutional arrangements. Existing literature on limited selections of well-established watershed-based organizations has provided valuable insights. The current research extends this focus by including a broad survey of watershed organizations from across the United States as a means to estimate a national portrait. Organizational characteristics include year of formation, membership size and composition, budget, guiding principles, and mechanisms of decision-making. These characteristics and the issue concerns of organizations are expected to vary with respect to location. Because this research focuses on organizations that are place based and stakeholder driven, the forces driving them are expected to differ across regions of the country. On this basis of location, we suggest basic elements for a regional assessment of watershed organizations to channel future research and to better approximate the organizational dynamics, issue concerns, and information needs unique to organizations across the country. At the broadest level, the identification of regional patterns or organizational similarities may facilitate the linkage among organizations to coordinate their actions at the much broader river basin or ecosystem scale.     

Lack of evidence for nepotism by workers tending queens of the polygynous termite <Emphasis Type="Italic">Nasutitermes corniger</Emphasis>

Kin selection theory predicts that workers in social insect colonies should preferentially aid close relatives over less related or unrelated individuals if such behaviors increase inclusive fitness. For example, a worker in a polygynous (multiple-queen) colony is predicted to tend its own mother rather than an unrelated queen if this nepotistic behavior increases its mother’s reproductive success in excess of costs. Despite predictions, experimental tests conducted in the social Hymenoptera have found no clear evidence of nepotism. No tests for nepotism have been carried out in the Isoptera (termites), another major insect taxon showing highly developed sociality. We tested for nepotistic behavior in the termite Nasutitermes corniger by determining if workers preferentially fed and groomed their mothers in a laboratory assay. We collected workers from nine naturally occurring multiple-queen colonies as they tended queens and determined their parentage using highly variable microsatellite markers. Our results provide no evidence that workers tend their mothers in preference to co-occurring queens. The absence of evidence for nepotism is consistent with previous results reported from numerous studies of eusocial hymenopterans.