The Potential Effects Of Acid Deposition On Aquatic Ecosystems Of The Sierra Nevada California

Acidic deposition and its effect on aquatic ecosystems have become major scientific and public policy issues in the United States since the early 1970s, and many diverse studies have been completed. This book is the first comprehensive, integrated synthesis of available information on current and potential effects of acidic precipitation on lakes and streams in geographic regions with a high number of low-alkalinity surface water from the Adirondacks and the Southern Blue Ridge to the Upper Midwest to the Rocky Mountains, the Sierra Nevada, and the Cascades. Written by leading authors, the book examines the current status of water chemistry and characterizes the processes controlling water chemistry on a regional basis by using and comparing high-quality data sets. Methods for the assessment of long-term changes in water chemistry and their effects in fish and other biota are also presented. The book amply illustrates the substantial diversity among geographical regions with respect to the nature of surface waters and the complexity of their response to acidic deposition. This volume will be of great interest to researchers in limnology, aquatic ecology, environmental chemistry, hydrology, and atmospheric sciences. It will also serve as an important reference for environmental managers and policy makers.

The 1977 Clean Air Act legally mandated the prevention of significant deterioration (PSD) of air quality related values (AQRVs) on wilderness lands. Federal land managers are assigned the task of protecting these wilderness values. This report contains guidelines for determining the potential effects of incremental increases in air pollutants on natural resources in wilderness areas of the National Forests of California. These guidelines are based on current information about the effects of ozone, sulfur, and nitrogen on AQRVs. Knowledge-based methods were used to elicit these guidelines from scientists and resource managers in a workshop setting. Linkages were made between air pollutant deposition and level of deterioration of specific features (sensitive receptors) of AQRVs known to be sensitive to pollutants. Terrestrial AQRVs include a wide number of ecosystem types as well as geological and cultural values. Ozone is already high enough to injure conifers in large areas of California and is a major threat to terrestrial AQRVs. Aquatic AQRVs include lakes and streams, mostly in high elevation locations. Current sulfur and nitrogen deposition is probably too low to warrant immediate concern in most areas (with the exception of nitrogen deposition at some locations in southern California), although the low buffer capacity of many aquatic systems in California makes them sensitive to potential future increases in acidity. Visibility is considered as a discrete AQRV. Guidelines are presented for determining degradation of visibility based on sensitive views in wilderness areas. Estimates of current deposition of ozone, sulfur, and nitrogen are compiled for all California wilderness areas. Recommendations are included for resource monitoring, data collection, and decision criteria with respect to the disposition of permit applications.

The completion of the initial phase of the U.S. National Acid Precipitation Assessment Program (NAPAP) in 1990 marked the end of the largest environmental research and assessment effort to that time. The resulting series of 27 State of Science and Technology (SOS/T) Reports and the NAPAP Integrated Assessment represent a decade of work by hundreds