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Abstract The new Swedish guidelines for the estimation of design floods for dams and spillways are presented, with emphasis on high-hazard dams. The method is based on a set of regional design precipitation sequences, rescaled for basin area, season and elevation above sea level, and a full hydrological model. A reservoir operation strategy is also a fundamental component of the guidelines. The most critical combination of flood generating factors is searched by systematically inserting the design precipitation sequence into a ten year climatological record, where the initial snowpack has been replaced by a statistical 30-year snowpack. The new guidelines are applicable to single reservoir systems as well as more complex hydroelectric schemes, and cover snowmelt floods, rain floods and combinations of the two. In order to study the probabilities of the computed floods and to avoid regional inconsistencies, extensive comparisons with observed floods and frequency analyses have been carried out. 相似文献
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Book reviewed in this article:
M. J. Hambrey and W. B. Harland (eds.): Eurth spre-Pleisro-cene glacial record 相似文献
M. J. Hambrey and W. B. Harland (eds.): Eurth spre-Pleisro-cene glacial record 相似文献
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JOAKIM DONNER 《Boreas: An International Journal of Quaternary Research》1980,9(4):270-270
Book reviewed in this article:
J. J. Lowe, J. M. Gray & J. E. Robinson (eds.): Studies in the Lateglacial of North-west Europe 相似文献
J. J. Lowe, J. M. Gray & J. E. Robinson (eds.): Studies in the Lateglacial of North-west Europe 相似文献
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JAN MANGERUD SVEND T. ANDERSEN BJÖRN E. BERGLUND JOAKIM J. DONNER 《Boreas: An International Journal of Quaternary Research》1974,3(3):109-126
Principles and terminology for classification of the Quaternary are discussed, including lithostratigraphy, biostratigraphy. morphostratigraphy, climatostratigraphy and chronostratigraphy. The main conclusion is a proposal for a common chronostratigraphical classification of the Quaternary in Norden (and partly continental NW Europe). The Quaternary is subdivided into the Pleistocene and the Holocene Series. The Pleistocene is further subdivided into several provisional stages (Weichselian, Eemian, etc.), based on the sequence of glacials/interglacials. but with the boundaries preferably defined by stratotypes. The Late Weichselian and the Flandrian (Holocene) are subdivided into chronozoncs (Bolling, Older Dryas, Allerød, Younger Dryas, Preboreal, Boreal, Atlantic, Subboreal, Subatlantic) with the boundaries dcfined in conventional radiocarbon years. 相似文献
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Radiocarbon dating of shells from marine Holocene deposits in the Disko Bugt area, West Greenland 总被引：1，自引：0，他引：1
JOAKIM DONNER HÖGNE JUNGNER 《Boreas: An International Journal of Quaternary Research》1975,4(1):25-45
Shells were collected from marine sediments in the area youth of Disko Bugt from various altitudes up to 50 m. Radiocarbon dates showed that only some of the shells were from sands and gravels formed at or near sea level and could be used to date the land/sea level changes. The shell dates show a regression from about 43 m at 7000 B.P. to about 8 m at 4000 B.P. All sediments with shells are Holocene in age, the oldest date being nearly 9000 B.P. The date of the Fjord Stage moraine in Orpigsoq is estimated at about 8000 B.P. on the basis of the altitude of the marine limit at 62 m. Extrapolations dated the older marine limits, falling from an altitude of 130 m to 80 m, at about 11,000 B.P. to 9000 B.P. These are approximate dates for the deglaciation of the area outside the Fjord Stage moraine. The distribution of shells in the sediments was shown to be largely dependent on habitat and water depth. At least some changes ill fauna were caused by a decrease of water depth due to the relative uplift of land. No tilting or warping of the land surface could he detected in the at-ea about 100 km long from the coast towards the Inland Ice. 相似文献
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Rapid tunnel-valley formation beneath the receding Late Weichselian ice sheet in Vendsyssel, Denmark 总被引：1，自引：0，他引：1
PETER B. E. SANDERSEN FLEMMING JØRGENSEN NICOLAJ KROG LARSEN JOAKIM H. WESTERGAARD ESBEN AUKEN 《Boreas: An International Journal of Quaternary Research》2009,38(4):834-851
Interpretation of Transient ElectroMagnetic (TEM) data and wire-line logs has led to the delineation of an intricate pattern of buried tunnel valleys, along with new evidence of glaciotectonically dislocated layers in recessional moraines in the central part of Vendsyssel, Denmark. The TEM data have been compared with recent results of stratigraphical investigations based on lithological and biostratigraphical analyses of borehole samples and dating with Optically Stimulated Luminescence (OSL) and radiocarbon. This has provided an overview of the spatial distribution of the late Quaternary lithostratigraphical formations, and the age of the tunnel valleys has been estimated. The tunnel valleys are typically 5–10 km long, 1 km wide and are locally eroded to depths of more than 180 m b.s.l. The valleys are interpreted to have been formed by subglacial meltwater erosion beneath the outermost part of the ice sheet during temporary standstills and minor re-advances during the overall Late Weichselian recession of the Scandinavian Ice Sheet. The formation of the tunnel valleys occurred after the retreat of the Main ice advance c . 20 kyr BP and before the Lateglacial marine inundation c . 18 kyr BP. Based on the occurrence of the tunnel valleys and the topography, four ice-marginal positions related to the recession of the northeastern Main advance and seven ice-marginal positions related to the recession from the following eastern re-advance across Vendsyssel are delineated. All the tunnel valleys were formed within a time interval of a few thousand years, giving only a few hundred years or less for the formation of the tunnel valleys at each ice-marginal position. 相似文献
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