Linking Theory and Practice for Restoration of Step-Pool Streams

Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches into steep terrain in response to population pressures, as stream channels in lower-gradient areas require stabilization due to hydrological alterations associated with land-use changes, and as step-pools are recognized for their potential to enhance stream habitats. Despite an increasingly voluminous literature and great demand for restoration using step-pool sequences, however, the link between theory and practice is limited. In this article, we present four unique cases of stream restoration using step-pools, including the evolution of the approaches, the project designs, and adjustments in the system following restoration. Baxter Creek in El Cerrito, California demonstrates an early application of artificial step-pools in which natural adjustments occurred toward geomorphic stability and ecological improvement. Restoration of East Alamo Creek in a large residential development near San Ramon, California illustrates an example of step-pools increasingly used in locations where such a channel form would not naturally occur. Construction of a step-pool channel in Karnowsky Creek within the Siuslaw National Forest, Oregon overcame constraints posed by access and the type and availability of materials; the placement of logs allowed natural scouring below steps. Dry Canyon Creek on the property of the Mountains Restoration Trust in Calabasas, California afforded a somewhat experimental approach to designing step-pools, allowing observation and learning in the future. These cases demonstrate how theories and relationships developed for step-pool sequences over the past two decades have been applied in real-world settings. The lessons from these examples enable us to develop considerations useful for deriving an appropriate course of design, approval, and construction of artificial step-pool systems. They also raise additional fundamental questions concerning appropriate strategies for restoration of step-pool streams. Outstanding challenges are highlighted as opportunities for continuing theoretical work.     

Water resources vulnerability assessment in the Adriatic Sea region: the case of Corfu Island

Cross-border water resources management and protection is a complicated task to achieve, lacking a common methodological framework. Especially in the Adriatic region, water used for drinking water supply purposes pass from many different countries, turning its management into a hard task to achieve. During the DRINKADRIA project, a common methodological framework has been developed, for efficient and effective cross-border water supply and resources management, taking into consideration different resources types (surface and groundwater) emphasizing in drinking water supply intake. The common methodology for water resources management is based on four pillars: climate characteristics and climate change, water resources availability, quality, and security. The present paper assesses both present and future vulnerability of water resources in the Adriatic region, with special focus on Corfu Island, Greece. The results showed that climate change is expected to impact negatively on water resources availability while at the same time, water demand is expected to increase. Water quality problems will be intensified especially due to land use changes and salt water intrusion. The analysis identified areas where water resources are more vulnerable, allowing decision makers develop management strategies.     

Variations in the Fluoride Level in Precipitation in a Region of Human Impact

The research concerns the Wielkopolski National Park (West Poland), which suffered a huge human impact in the 1970s and 1980s owing to the nearby location of an industrial plant. Since then, fundamental technological changes that it introduced into its production of phosphate fertilizers have radically reduced the amount of pollution emitted. A three-year study (2002–2004) of fluorides in precipitation in open terrain and under tree crowns showed their concentrations to range from levels below the detection limit (0.003 mg/l) to 0.560 mg/l. Those registered under tree crowns were several times higher and indicated substantial dry deposition of fluorides on the trees. The highest values were recorded in 2003, with 43% of samples ranging from 0.01 to 0.05 mg/l, and with 51% of throughfall ranging from 0.10 to 0.50 mg/l. A strong connection was shown to exist between fluoride and sulphate concentrations in the precipitation. An analysis was made of the available data on F concentrations in the air and the dust levels around the factory, but these figures did not show an unequivocal effect on F concentrations in precipitation. A great similarity was found to occur between the fluoride content in rainwater in the Wielkopolski National Park and in the centre of the nearby Poznań metropolitan area, which indicates that there are also other F sources besides the local factory.     

Applying tqem practices to pollution prevention at AT&T's columbus works plant

In recent years AT&T changed its focus on environmental policies from compliance to pollution prevention. Pollution prevention is an integrated program that includes design for the environment, “green” manufacturing, and a comprehensive program to reduce existing waste in production. The principles of Total Quality Management can be applied to pollution prevention as well as the more traditional manufacturing concepts. The project described in this article is one of several concurrent programs being conducted at AT&T'S Columbus Works to reduce overall waste produced by the facility by applying TQM practices.     

VOLATILE ORGANIC COMPOUNDS IN GROUND WATER FROM RURAL PRIVATE WELLS, 1986 TO 19991

ABSTRACT: The U.S. Geological Survey (USGS) collected or compiled data on volatile organic compounds (VOCs) in samples of untreated ground water from 1,926 rural private wells during 1986 to 1999. At least one VOC was detected in 12 percent of samples from rural private wells. Individual VOCs were not commonly detected with the seven most frequently detected compounds found in only 1 to 5 percent of samples at or above a concentration of 0.2 microgram per liter (μg/l). An assessment level of 0.2 μg/l was selected so that comparisons of detection frequencies between VOCs could be made. The seven most frequently detected VOCs were: trichloromethane, methyl tert‐butyl ether, tetrachloroethene, dichlorodifluoromethane, methylbenzene, 1,1,1‐trichloroethane, and 1,2‐dibromo‐3‐chloropropane. Solvents and trihalomethanes were the most frequently detected VOC groups in private wells. The distributions of detections of gasoline oxygenates and fumigants seemed to be related to the use patterns of compounds in these groups. Mixtures were a common mode of occurrence of VOCs with one‐quarter of all samples with detections including two or more VOCs. The concentrations of most detected VOCs were relatively small and only 1.4 percent of samples had one or more VOC concentrations that exceeded a federally established drinking water standard or health criterion.     

Regional planning acceptance by residents of Northern New York,USA

This study compares the effectiveness of two regional planning agencies in terms of public support for various planning activities. The Adirondack Park Agency and the Temporary State Commission on Tug Hill have fundamentally different approaches to planning. The Adirondack Park Agency has implemented a restrictive regulatory program with little citizen participation by Adirondack residents. The Tug Hill Commission has implemented an advisory and coordinating program with an emphasis on public input. Residents of two towns in each region were surveyed to determine environmental concern and support for regional planning activities. Respondents from both regions favored a planning agency that incorporates citizen input; controls air, water, and toxic waste pollution; and develops recreation areas. They strongly opposed an agency that regulates private land-use. Basic demographic characteristics and levels of environmental concern were similar in all four towns, but receptivity to various planning activities was consistently greater among residents of the Tug Hill Region. Paired comparisons of the four towns demonstrated no differences between towns of the same region and significant differences between towns of different regions. Public support for regional planning is greater in the Tug Hill Region than in the Adirondack Park.     

Eight-Hour Ozone Trends at Sites in Lake Michigan Ozone Nonattainment Areas

ABSTRACT

Temperature-adjusted trends in 1-hr and 8-hr ozone averages were calculated for ten sites near Lake Michigan for 1980-1995. Results show that ozone trends declined similarly according to both metrics for sites on the west side of the lake. This suggests that the factors underlying the trends were similar. These factors include, among others, ozone control programs designed to address the 1-hr standard. Thus, these control programs may have been similarly effective in moving these sites toward compliance with the 8-hr standard.     

Methane oxidation in a crude oil contaminated aquifer: Delineation of aerobic reactions at the plume fringes

High resolution direct-push profiling over short vertical distances was used to investigate CH(4) attenuation in a petroleum contaminated aquifer near Bemidji, Minnesota. The contaminant plume was delineated using dissolved gases, redox sensitive components, major ions, carbon isotope ratios in CH(4) and CO(2), and the presence of methanotrophic bacteria. Sharp redox gradients were observed near the water table. Shifts in δ(13)C(CH4) from an average of -57.6‰ (±1.7‰) in the methanogenic zone to -39.6‰ (±8.7‰) at 105m downgradient, strongly suggest CH(4) attenuation through microbially mediated degradation. In the downgradient zone the aerobic/anaerobic transition is up to 0.5m below the water table suggesting that transport of O(2) across the water table is leading to aerobic degradation of CH(4) at this interface. Dissolved N(2) concentrations that exceeded those expected for water in equilibrium with the atmosphere indicated bubble entrapment followed by preferential stripping of O(2) through aerobic degradation of CH(4) or other hydrocarbons. Multivariate and cluster analysis were used to distinguish between areas of significant bubble entrapment and areas where other processes such as the infiltration of O(2) rich recharge water were important O(2) transport mechanisms.     

The effects of pruning and nodal adventitious roots on polychlorinated biphenyl uptake by Cucurbita pepo grown in field conditions

Two cultivation techniques (i-pruning and ii-nodal adventitious root encouragement) were investigated for their ability to increase PCB phytoextraction by Cucurbita pepo ssp pepo cv. Howden (pumpkin) plants in situ at a contaminated industrial site in Ontario (Aroclor 1248, mean soil [PCB] = 5.6 μg g⁻¹). Pruning was implemented to increase plant biomass close to the root where PCB concentration is known to be highest. This treatment was found to have no effect on final shoot biomass or PCB concentration. However, material pruned from the plant is not included in the final shoot biomass. The encouragement of nodal adventitious roots at stem nodes did significantly increase the PCB concentration in the primary stem, while not affecting shoot biomass. Both techniques are easily applied cultivation practices that may be implemented to decrease phytoextraction treatment time.