ESTIMATING EROSION RISKS ASSOCIATED WITH LOGGING AND FOREST ROADS IN NORTHWESTERN CALIFORNIA1

ABSTRACT: Erosion resulting from logging and road building has long been a concern to forest managers and the general public. An objective methodology was developed to estimate erosion risk on forest roads and in harvest areas on private land in northwestern California. It was based on 260 plots sampled from the area harvested under 415 Timber Harvest Plans completed between November 1978 and October 1979. Results confirmed previous findings that most erosion related to forest management occurs on a small fraction of the managed area. Erosion features larger than the minimum size inventories in this study (> 13 yd³) occupied only 0.2 percent of the area investigated. Linear discriminant analysis was used to develop two equations for identifying critical sites (sites with erosion >100 yd³ac^?1). The equations were based on slope, horizontal curvature (an expression of local topography), and soil color (on road sites) or the strength of the underlying rocks (on harvest sites). The equations can be used in planning to estimate the erosion risk of proposed activities. They can also be used to estimate acceptable risk thresholds based on the value of competing resources.     

Biosolids-amended soils: Part II. Chemical lability as a measure of contaminant bioaccessability.

Biosolids recycling by amending agricultural soils has increased significantly over the last few decades. The presence of contaminants in small, bioavailable quantities has generated concerns about health threats resulting from accumulation of potential toxins in the food chain. In this study, land application of biosolids was evaluated for environmental risk. Chemical lability tests for metals were used for the test soils and included analyses for water soluble, exchangeable, and metals extractable by the physiologically based extraction test. Chemical extractions detected slight increases in labile metal concentrations for many of the treated soils, particularly those receiving long-term applications of 5 years or more. Significantly higher metal concentrations were observed in the soils that had been exposed to biosolids before the U.S. Environmental Protection Agency (Washington, D.C.) 503 Rule (U.S. EPA, 2004) was implemented.     

Environmental education in Sweden

Summary Schools and higher education institutions in Sweden have developed a wide range of innovative and demanding curricula to meet the objectives of Sweden's environmental policy. Environmental education in compulsory schools is taught principally through biological sciences, although social studies are beginning to occupy a substantial component of the environmental curriculum. Upper secondary schools offer more opportunities to develop environmental awareness, understanding and practical skills than comparable sixth form and post-secondary colleges in England. In Sweden there is a strong emphasis on practical work developed through projects based on contemporary environmental issues and their resolution. The development of environmental education has been well supported by a substantial input of new resources, especially materials developed by the Swedish Environmental Protection Agency and Industry. Universities have also begun to adopt new organisational structures to help develop inter-disciplinary teaching and research teams. Several universities are experimenting with common core courses, parts of which comprise environmental elements.Dr P. Brown is currently Visiting Professor of Environmental Education, in the School of Natural Sciences at the University of Hertfordshire. All five authors were until recetly members of Her Majesty's Education Service Inspectorate.     

THE EFFECT OF EL NIÑO-RELATED DROUGHT ON THE RECOVERY OF ACIDIFIED LAKES

Although SO₂ emissions and deposition rates havedeclined substantially since the implementation of sulphuremission control programmes in North America [1], recovery(measured as decreases in concentrations) of affected lakes in central Ontario has been much less substantial thananticipated based on the decrease in deposition. The slowrecovery is attributed to the reoxidation and release of storedsulphur in catchments. Reduced sulphur retained in previousyears when sulphur deposition was higher is exposed to air andoxidized during severe droughts, then exported duringsubsequent wet periods. Elevated stream concentrations and export rates occur in the autumns of yearswith prolonged severe droughts, particularly in catchments withextensive wetlands. Drought in our study catchments occurred inyears following strong El Niño events. When the SouthernOscillation Index (SOI) was strongly negative (1976–77, 1982–83,1986–87, 1991–92, 1993–94) the frequency of occurrence ofdrought the following summer in small catchments with shallowoverburden was extremely high. A lakes rate of recovery fromacidification depends upon the amount of excess reduced Sthat has been stored in anoxic zones in the catchment (largely afunction of the extent of wetlands) during years of elevated Sdeposition rates, and the frequency and severity of droughts. Iflong-term changes in global or regional climate alter thefrequency or magnitude of El Niño-related droughts, therecovery of acidified lakes will be affected.     

Modeling radium and radon transport through soil and vegetation

A one-dimensional flow and transport model was developed to describe the movement of two fluid phases, gas and water, within a porous medium and the transport of 226Ra and 222Rn within and between these two phases. Included in this model is the vegetative uptake of water and aqueous 226Ra and 222Rn that can be extracted from the soil via the transpiration stream. The mathematical model is formulated through a set of phase balance equations and a set of species balance equations. Mass exchange, sink terms and the dependence of physical properties upon phase composition couple the two sets of equations. Numerical solution of each set, with iteration between the sets, is carried out leading to a set-iterative compositional model. The Petrov-Galerkin finite element approach is used to allow for upstream weighting if required for a given simulation. Mass lumping improves solution convergence and stability behavior. The resulting numerical model was applied to four problems and was found to produce accurate, mass conservative solutions when compared to published experimental and numerical results and theoretical column experiments. Preliminary results suggest that the model can be used as an investigative tool to determine the feasibility of phytoremediating radium and radon-contaminated soil.     

WATER SUPPLY OPTIONS IN A NEW MEXICO WATER PLANNING REGION1

ABSTRACT: The population in the Jemez y Sangre Water Planning Region of New Mexico has reached the point at which the demand for water exceeds available supplies, particularly when precipitation is below average, as has frequently occurred in recent years. The desire to develop a sustainable water supply that relies on renewable supplies in wet years and preserves the water in storage for times of drought motivated a diverse set of stakeholders in the region to participate in regional water planning. The planning effort culminated in development of the Jemez y Sangre Regional Water Plan, which was adopted by municipal and county governments in the region. The plan assesses and compares water supply and demand in the region and recommends alternatives for protecting and restoring the existing water supply and addressing the pending gap between supply and demand anticipated by the year 2060. To convey to decision makers the alternatives available to solve the future water shortage, option charts were developed to portray the amount of water that could be obtained or conserved through their implementation. The option charts show that the projected gap between supply and demand cannot be met through one alternative only, but will require a combination of alternatives.