Maryland's Green Infrastructure—Using Landscape Assessment Tools to Identify a Regional Conservation Strategy

Maryland is growing at a very rapid pace. Compounding the problems associated with rapid growth is the scattered pattern of development that consumes an excessive amount of land and fragments the landscape. As land use changes, wildlife habitat and migration corridors are lost and normal ecosystem functions are disturbed or destroyed. While land use planners and developers are attempting to minimize such impacts, they do not always know where key natural lands and corridors are situated. The Green Infrastructure Assessment (GIA) provides this information and can be used to identify a greenway network that will protect the most critical lands in the state before they are gone foreover. Using GIS and principles of landscape ecology, the Maryland Department of Natural Resources is identifying an interconnected network of "hubs" and "corridors" that are now the focus of state and local agency deliberations and revisions. Elements of the network are being prioritized for conservation and restoration activities based on ecological parameters (e.g., sensitive species, important wetlands or riparian zones, etc.) and threat parameters (e.g., protection status, development pressure, etc.). The goal of GIA is to help identify an ecologically sound open space network, and ultimately, to incorporate the agreed upon network into state and local land conservation planning.     

Bio-indicators and the quality of the Wadden Sea

The definitions of the notions bio-indicator and water quality are critically reviewed; it is shown that both have been used ambiguously.The quality of the Wadden Sea is discussed using a number of indicators for pollution effects; the Wadden Sea is now an unsuitable environment for a number of marine mammals, and, to a lesser extent, for some bird species. It cannot be shown whether or not this pollution has any effect on r-selective species.Paper presented at a Symposium held on 14 and 15 October 1982, in Utrecht, The Netherlands.     

Climate and Water Conflicts Coevolution from Tropical Development and Hydro‐Climatic Perspectives: A Case Study of Costa Rica

Costa Rica is a nation with a vast wealth of water resources; however, recently the country has faced water conflicts (WC) due to social, economic, legal, and political impediments in response to limited water availability during El Niño events and inefficient use of its water resources. This study presents a spatial distribution and temporal analysis of WC in Costa Rica from 2005 to 2015. In total, 719 WC were analyzed of which 54% were among private individuals and government. The largest urban areas and the Grande de Tárcoles Basin were identified as the main “hot spot” for the conflicts. WC were mainly caused by spills of wastewater, water pollution, water shortage, infrastructure damage, and flooding, and can be predicted using a multiple linear model including the population size and the number of hydro‐meteorological events (HME) (R² = 0.77). The identified HME also coevolved significantly with the changes in precipitation regimes (r = 0.67, p = 0.021). Our results suggest that there is a need to recognize that water infrastructure longevity across the country concatenates and amplifies WC, mainly in the most populated area located in the Central Valley. Implications of our findings include the need for truly integrated water resources management plans that include, for example, WC as indicators of hydro‐climatic changing conditions and water supply and sanitation infrastructure status.     

Nanotechnology and groundwater remediation: A step forward in technology understanding

Nanotechnology application to contaminated site remediation, and especially the use of nanoscale zero‐valent iron particles to treat volatile organic compound (VOC)‐impacted groundwater, is now recognized as a promising solution for cost‐effective in situ treatment. Results obtained during numerous pilot tests undertaken by Golder Associates between 2003 and 2005 in North America (United States and Canada) and Europe have been used to present a synthetic cross‐comparison of technology dynamics. The importance of a comprehensive understanding of the site‐specific geological, hydrogeological, and geochemical conditions, the selection of appropriate nanoscale particles, the importance of monitoring geochemical parameters during technology application, and the potential of nanoparticle impact on microbial activity are discussed in this article. The variable technology dynamics obtained during six pilot tests (selected among numerous other tests) are then presented and discussed. © 2006 Wiley Periodicals, Inc.     

Field and laboratory evaluation of the treatment of DNAPL source zones using emulsified zero‐valent iron

Emulsified zero‐valent iron (EZVI) is a surfactant‐stabilized, biodegradable emulsion that forms droplets consisting of a liquid‐oil membrane surrounding zero‐valent iron (ZVI) particles in water. This article summarizes the results obtained during the first field‐scale deployment of EZVI at NASA's Launch Complex 34 (LC34) located on Cape Canaveral Air Force Station, Florida, in August 2002 and presents the results of recent follow‐on laboratory tests evaluating the mechanisms, which contribute to the performance of the technology. The field‐scale demonstration evaluated the performance of EZVI containing nanoscale zero‐valent iron (NZVI) when applied to dense, nonaqueous phase liquid (DNAPL) trichloroethylene (TCE) in the saturated zone. Results of the field demonstration indicate substantial reductions in TCE soil concentrations (greater than 80 percent) at all but two soil boring locations and significant reductions in TCE groundwater concentrations (e.g., 60 percent to 100 percent) at all depths targeted with EZVI. Laboratory tests conducted in 2005 suggest that both NZVI particles and EZVI containing NZVI can provide significant reductions in TCE mass when used to treat TCE DNAPL in small test reactors. However, EZVI was able to reduce TCE concentrations to lower levels than were obtained with NZVI alone, likely as a result of the combined impact of sequestration of the TCE into the oil phase and degradation of the TCE with the NZVI. © 2006 Wiley Periodicals, Inc.     

SPATIAL VARIATION OF NUTRIENT BALANCE IN THE TRUCKEE RIVER,CALIFORNIA‐NEVADA1

ABSTRACT: Because the Truckee River connects two lakes along the Eastern Sierra Nevada Mountains with different limiting nutrients, this research addresses whether the nitrogen:phosphorus (N:P) balance of the river ecosystem changes longitudinally. Historical (1990 to 2000) total nitro‐gen:total phosphorus (TN:TP) ratios in river water exhibited the expected gradient from high N:P ratios upstream to low N:P ratios downstream, with the major gradient of the N:P balance occurring within the transition between montane and high desert terrain. During 2001, the river contained anomalously low total nitrogen concentrations in the far upper reaches and dissolved inorganic nitrogen concentrations in the lower reaches, resulting in a less apparent longitudinal gradient of N:P ratios. Measurements of periphyton growth and physiology (nutrient bioassays and ectoenzyme activities) and stoichiometry during the summer of 2001 also exhibited a complex picture of the spatial variation of N:P balance that was not entirely consistent with a strong N:P gradient. However, the compendium of the indicators did support the overall picture of an overarching longitudinal gradient from high to low N:P ratios. The results suggest that periphyton management efforts in the Truckee River should consider the overall spatial gradient as well as the small‐scale dynamics of the stream ecosystem structure.     

Experience with the use of LCA-modelling (EASEWASTE) in waste management.

Life-cycle assessment (LCA) models are becoming the principal decision support tools of waste management systems. This paper describes our experience with the use of EASEWASTE (Environmental Assessment of Solid Waste Systems and Technologies), a new computerized LCA-based model for integrated waste management. Our findings provide a quantitative understanding of waste management systems and may reveal consistent approaches to improve their environmental performances. EASEWASTE provides a versatile system modelling facility combined with a complete life-cycle impact assessment and in addition to the traditional impact categories addresses toxicity-related categories. New categories dealing with stored ecotoxicity and spoiled groundwater resources have been introduced. EASEWASTE has been applied in several studies, including full-scale assessments of waste management in Danish municipalities. These studies led to numerous modelling issues: the need of combining process-specific and input-specific emissions, the choice of a meaningful time horizon, the way of accounting for biological carbon emissions, the problem of stored ecotoxicity and aspects of crediting the waste management system with the savings inherent in avoided production of energy and materials. Interpretation of results showed that waste management systems can be designed in an environmentally sustainable manner where energy recovery processes lead to substantial avoidance of emissions and savings of resources.