Catchment area

Bimetallic corrosion in atmospheres is confined to the area of the less noble metal in the vicinity of the bimetallic joint, owing to the high electrolytic resistance of the condensed electrolyte film. Electrolytic resistance considerations limit the effective anodic and cathodic areas to approximately equal size and therefore prevent alleviation of atmospheric galvanic corrosion through strict application of the catchment area principle. 

In all cases where water is used for cooling, but more especially where it is being evaporated, the hardness figure should be obtained from the local water supply authority. Enquiries should also be made as to possible variations in the supply, since many cities draw their water from two or more catchment areas, and the type and quantity of hardness may change. 

Imhoff, K. R., Koppe, P. and Dietz, F. (1980). Heavy metals in the Ruhr River and their budget in the catchment area. Progr. Water Technol. 12, 735-749. 

The Llobregat River (NE Spain) is 156 km long and covers a catchment area of about 4,957 km. Its watershed is heavily populated (more than three million inhabitants). 

Regier DA, Farmer ME, Rae DS, et al Comorhidity of mental disorders with alcohol and other drug abuse results from the Epidemiologic Catchment Area (EGA) Smdy. JAMA 264 2511-2518, 1990... 

Narrow WE, Regier DA, Rae DS, et al (1993). Use of services by persons with mental and addictive disorders. Findings from the National Institute of Mental Health Epidemiologic Catchment Area Program. 

The description of a water body and its catchment area underpins the pressures and impacts analysis. Useful information includes climate, geology, and land and soil use. In addition to a general description of the water body, it is essential to identify the driving forces that may be exerting pressures on the water body. Driving forces... 

It is also essential to consider that a specific pressure will not always cause a particular impact. Scale, both temporal and spatial, is one of the issues that determines the impact of a pressure. Other characteristics of the catchment area of the water body may also have an influence and the particular characteristics relates to the nature of the pressure. 

In summary, a successful pressures and impact assessment will be a study in which there is a proper understanding of the objectives, a good description of the water body and its catchment area (including monitoring data), and a knowledge of how the catchment system functions. 

Nelson, E., Rice, J. (1997). Stability of diagnosis of obsessive-compulsive disorder in the Epidemiologic Catchment Area Study. American Journal of Psychiatry,... 

Robins, L. N., Locke, B. Z.,. Regier, D. A. (1991). An overview of psychiatric disorders in America. In L. N. Robins D. A. Regier (Eds.), Psychiatric disorders in America The Epidemiologic Catchment Area Study (pp. 328-366). New York Free Press. 

The podzol profile samples were taken from the groundwater catchment areas from humus (A0) eluvial (A) and illuvial (B) horizons and the parent material (C). In coarse-grained sand areas the profile waspoorly developed and mainly 20 cm thick, the thickness in till areas ranged from 40 to 80 cm. 

Relatively high contents of As in Drava River samples (ME-23 and ME-24) are a consequence of the Drava River catchment area characteristics. 

Fig. 2. Derivation of natural background levels by (a) superimposing sample points on geological units (left) and by (b) relating sample points to catchment areas (right).

FIGURE 8.6. The Emscher river catchment area with existing and originally planned biologi-cal/chemical wastewater treatment plants. 

Figure 9 gives the simplified mass balance for heavy metals in a catchment, including both a soil compartment in the catchment area and the aquatic system with water and sediment compartments. A complete steady-state mass balance of heavy metals for a catchment equals ... 

The runoff export was about 0.03 g/ha of Hgt per year. This value lies within the range of 0.008 to 0.059 g Hg/ha/yr, derived from a number of catchment studies in Sweden. The output of methylmercury from catchment area was 0.0015 g/ha/yr of Hg. This is substantially lower than the input to the catchment. There appears to be an ongoing net accumulation of Hgm in the terrestrial ecosystems, similar to the pattern previously shown for the total mercury. 

These uncertainties and differences in interpretation would be less important were it not for the environmental and economic aspects of the issue described in preceding sections of this chapter. If the Recommendation were honoured to the letter and all OSPAR area chlor-alkali plants were to be forced to close or convert by 2010, we would see no environmental gain but considerable economic and social damage. EU lawyers might also like to consider the situation for major producer countries like France and Spain where some of their plants are within the OSPAR catchment area and others - with drainage to the Mediterranean basin -are not ... 

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