ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01132.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01133.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01135.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThis paper considers the development of standards for the discharge of wastewaters from the perspectives of (a) the developed world, (b) the developing world, and (c) the newly industrializing nations. It considers the potential environmental benefits which can be obtained by the imposition of stringent effluent standards, and weighs this against the economic costs of meeting such standards. By means of case studies it considers how inappropriate standards can often arise in other countries of the world and how the imposition of unjustifiably high standards can be demoralizing, costly, and produce no environmental improvements. Finally, it considers how a more pragmatic approach to the setting of standards, especially in the newly industrializing and developing nations, place them in context of applicability, affordability, regulation and enforcement.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01136.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe introduction of ultraviolet disinfection in Jersey has achieved significant improvements in water quality. However, bathing waters in St Aubin's Bay and shellfish flesh have failed to comply with microbial standards. Streams and seepages from coastal structures were investigated as potential indicator organism sources (total and faecal coliforms, faecal streptococci). Seepages were an unimportant bacterial source as concentrations were low. Geometric mean concentrations in streams were up to four orders of magnitude higher than in final sewage‐treatment works effluent, and concentrations increased significantly at high stream discharge. Rainfall‐induced pulses of poor water quality occurred two to three times per week during the 1993 summer season. Natural discharges from island catchments thus contribute significantly to the bacterial load received at the coast, especially during high flow events. These observations have implications for other UK and European schemes using tertiary disinfection technology to attain water quality targets in coastal wat

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01137.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe construction of a road, runway or other paved surface on the outcrop of an aquifer introduces an impermeable area into an otherwise permeable environment. Surface water must be drained from these areas, and the most convenient and inexpensive way of disposing of this water is usually to lead it into soakaways in the unsaturated zone of the aquifer. This approach is acceptable in that it can provide valuable recharge to aquifers in times of low rainfall. However, it carries the risk that pollutants from the surface can also be carried into the aquifer. These pollutants can be generated from (a) normal abrasion, (b) maintenance operations such as de‐icing and defoliation, and (c) accidental spillages. Although there is evidence that such drainage can carry a pollutant load, and that drainage entering soakaways can reach a public‐ supply well, there does not seems to be any evidence available at present of any public supply in the UK being seriously affected by such drain

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01138.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe Kannai‐Yamashita district, which is Yokohama's administrative and economic heart, was the first part of the city to be installed with a modern sewerage system. This district is served by combined sewers, many of which have extensive pipe deterioration, shallow covering, and insufficient capacity. Whilst rehabilitation of these sewers has therefore been an urgent priority, flood alleviation has been given even greater precedence.It was consequently decided (a) to construct supplementary storm trunk sewers and a stormwater pumping station to mitigate flooding, and (b) to implement a systematic rehabilitation of the sewers on a gradual basis. Studies of branch sewer rehabilitation also used a surcharge model in the interest of achieving an economical and efficient desig

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01139.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTWater levels in the lower reaches of most rivers are controlled by the interaction of fluvial flows and tides. Assessment of the risk of over‐bank inundation therefore requires an estimation of the probability of experiencing combinations of river floods and high tides and calculation of the water levels resulting from their interaction. This may be achieved by numerical integration of the marginal probability distributions of river floods and sea‐levels, but this is complex mathematically and requires explicit knowledge of the correlation structure. In this paper a solution is developed for risk assessment in the lower River Roding, by reconstructing the historical water levels from river flow and tidal records using a hydraulic model. The resulting water‐level series is then analysed statistically to estimate the probability that certain critical levels will be exceeded. The model allows for operation of the River Roding's flood‐protection barrier and for the effects of a general rise in se

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01140.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe paper describes a project in which colour and infra‐red video images were used as the basis for assessing the percentage impermeability of subcatchments for a WALLRUS model. The imagery was obtained from helicopter‐mounted video cameras. Computer processes were developed to convert raw data, which were in analogue format, into a format which could be manipulated and displayed by the computer. The computer was able to assess the total permeable and impermeable areas in each subcatchment. These data were used in the WALLRUS model and compared with the results obtained using manually derived data and results from the flow verification sur

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01141.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTBetween 1988 and 1992, an asset study of North West Water Limited's three largest aqueducts was carried out to assess their condition and rehabilitation needs. About 360 km of the aqueduct system, including approximately 1700 structures, 160 km of tunnel and conduit, 700 km of pipeline and 4000 valves, were covered by the study. A wide range of survey techniques was used, some being specially developed as part of the study, and a unified system of condition assessment and prioritization of rehabilitation needs was devised.The paper (a) describes the overall approach and survey techniques, (b) discusses the methods of assessment used, (c) summarizes the conditions of the assets whose ages vary from 20–100 years, and (d) reviews some of the rehabilitation works proposed and execute

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01142.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY