An essential part of the environmental assessments is the characterization of the subsurface hydrogeology. Hydrogeological characterization involves establishing the hydrologic and geologic conditions and incorporating this information into groundwater flow and contaminant transport models.
Landfill Gas Emissions Model (LandGEM) estimates air pollutant emissions from municipal solid waste (MSW) landfills. The model can be used to estimate emission rates for methane, carbon dioxide, nonmethane organic compounds, and individual air pollutants from landfills. It can also be used by landfill owners and operators to determine if a landfill is subject to the control requirements of the federal New Source Performance Standard (NSPS) for new MSW landfills or the emission guidelines for existing MSW landfills. The model is based on a first order decay equation and can be run using site-specific data are available, using default values: one set based on the requirements of the NSPS and emission guidelines, and the other based on emission factors in EPA`s Compilation of Air Pollutant Emission Factors, AP-42.
Fires that burn through forests cause changes in wood anatomy and growth that can be used to reconstruct fire histories. Fire is important in Sequoia sempervirens (D. Don) Endl. (coast redwood) forests, but fire histories are limited due to difficulties crossdating annual rings of this species. Here we investigated three fires (1985, 1999, 2008) in two old-growth forests (Montgomery Woods State Natural Reserve and Landels-Hill Big Creek Reserve, California, USA) to quantify these responses via crossdated increment cores from lower trunks of 53 trees, including 10 that were climbed and cored at 10 m height intervals. Redwoods frequently responded to fire by producing anomalous growth during the fire year; 100 of 240 lower trunk cores recorded at least one anatomical indicator (i.e., intra-annual density fluctuation, faint latewood, resin, or scar). Following fire, radial growth decreased by 29% to 43% compared to the fire year. After accounting for climatic influences, radial growth was 27% to 32% lower than expected in the post-fire year and declined to as low as 46 % after three years. Growth suppression persisted for up to seven years after fire, followed by up to 40% higher than expected radial growth. Several of the climbed trees expressed disruption of incremental growth along the height gradient following fire. The 1985 event consistently generated stronger growth and anatomical responses than the 1999 and 2008 events, and showed a co-occurrence between faint latewood during the fire year and subsequent narrow or missing rings. We used post-fire low growth relative to drought combined with anatomical indicators to detect past fires, identifying five additional events at Landels-Hill Big Creek Reserve dating back to 1634. Although other disturbances could have initiated these responses, our detection method enhances current capabilities for the spatiotemporal resolution of redwood fire histories via non-scar indicators on increment cores from living redwoods.
This document provides the geophysical logs ABP-3C to MSB-17BB for the Groundwater Transport investigation and determination of the hydrogeologic setting of the A/M Area.
Soil degradation is one of the most serious ecological problems in the world. In arid and semi-arid northern China, soil degradation predominantly arises from wind erosion. Trends in soil degradation caused by wind erosion in northern China frequently change with human activities and climatic change. To decrease soil loss by wind erosion and enhance local ecosystems, the Chinese government has been encouraging residents to reduce wind-induced soil degradation through a series of national policies and several ecological projects, such as the Natural Forest Protection Program, the National Action Program to Combat Desertification, the “Three Norths” Shelter Forest System, the Beijing-Tianjin Sand Source Control Engineering Project, and the Grain for Green Project. All these were implemented a number of decades ago, and have thus created many land management practices and control techniques across different landscapes. These measures include conservation tillage, windbreak networks, checkerboard barriers, the Non-Watering and Tube-Protecting Planting Technique, afforestation, grassland enclosures, etc. As a result, the aeolian degradation of land has been controlled in many regions of arid and semiarid northern China. However, the challenge of mitigating and further reversing soil degradation caused by wind erosion still remains.
This document provides potentiometric and isoconcentration maps of the Savannah River A/M Area. These are presented as part of the determination of the hydrogeologic setting of the A/M Area in studying ground water transport.
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