Fire Severity,Water Repellency Characteristics and Hydrogeomorphological Changes Following the Christmas 2001 Sydney Forest Fires

Soil water repellency can enhance overland flow and erosion and may be altered by fire. The Christmas 2001 bushfires near Sydney allowed investigation of the relationship between fire severity, water repellency and hydrogeomorphological changes. For two sub-catchments with differences in fire severities in Nattai National Park, south-west of Sydney, this paper considers: (1) the links between fire severity based on SPOT image analysis and ground observation of fire severity and repellency; (2) the textural and organic/minerogenic characteristics of eroded sediment; and (3) erodibility, erosion and deposition of soils in both catchments. Ground surveys show that image analysis reflects well the degree of vegetation consumption by fire, but cannot adequately predict the degree of ground litter consumption, associated soil heating and repellency effects. Fire had varying effects on repellency, leaving it unchanged, destroying it or enhancing it, depending on the soil temperature reached. The main post-fire hydrogeomorphological changes have been widespread erosion and colluvial and alluvial deposition of topsoil in foot-slope locations and river systems, but only localised redistribution of the highly erodible, repellent sandy subsurface layer. The fire did not trigger major geomorphological change in the study area, but fires probably cause important topsoil and nutrient depletion and may also affect water quality.     

Water Quality of Small Rivers in the Zone of Influence of Gold-Mining Facilities in Krasnoyarsk Region

Environmental and sanitary estimation of small-river water quality is made in the zone of influence of gold-mining facilities in Krasnoyarsk Region. The estimates are based on data on the hydrochemical regime and the characteristics of phytoplankton, microphyto-periphyton, macrozoobenthos, and ichthyofauna collected during the vegetation period of 2000.     

Monthly Dispersion Characteristics over the South China Sea for Air Quality Modeling

— Monthly dispersion characteristics for air quality modeling over the South China Sea offshore the west coast of Borneo are studied using long-term ship measurements. It is found from monthly averages that the stability condition is nearly neutral throughout the year with the exception of April, May, and November which are slightly unstable. The lifting condensation level ranged from 338 to 450 m. The lowest value of the ventilation factor occurred in April and the highest in January. The friction velocity for each month is also provided to determine the vertical eddy diffusivity and horizontal and vertical dispersion coefficients.     

The Effect of the Development of Groundwater Deposits on Its Fluorine Content

Synthesis of regime observations of groundwater quality at deposits under operation and thermodynamic modeling of the geochemical interaction processes that govern the groundwater chemistry were used to recognize the geochemical causes and processes that bring about an increase in the groundwater fluorine content during water withdrawal accompanied by groundwater level drop and partial drying of the aquifer. The causes of the invalidity of previous forecasts are established.     

Modeling Lake Ladoga Zoobenthos and Studying Its Role in Phosphorus Exchange at the Water–Bed Interface

A zoobenthos submodel is included in an ecosystem model. The new model is used to assess the role of zoobenthos in the phosphorus exchange at the water–bed interface, in particular, the phosphorus cycle in the water body ecosystem is described more accurately. The calculated zoobenthos distribution over the bed of a lake can be used in modeling the lake ichthyocenoses.     

Analysis of Numerical Procedures for Solving Mass Transport Problems at a Regional Scale

The principal mass transport models and the ways of their implementation are considered. Some problems associated with the application of numerical methods for mass transport modeling in problems of dissolved chemicals migration at a regional scale are discussed. A new method proposed in this study allows the determination of the space structure of a groundwater flow and the simulation of steady-state convective mass transport.