When hydraulic design decisions are made in a watershed, engineers rely on estimation of the design discharge. Historically, they have applied empirical methods to do this, but empirical methods can only describe the hydrologic characteristics of the watersheds from which they were derived. Although more advanced methods now exist, engineers find them challenging to use because of the abundant ...

Advances in computational tools and modelling techniques combined with enhanced process knowledge have, in recent decades, facilitated a rapid progress in hydrologic modelling. From the use of traditional lumped models, the hydrologic science has moved to the much more complex, fully distributed models that exude an enhanced knowledge of hydrologic processes. Despite this progress, uncertaintie...

Research on ecosystem and societal response to global environmental change typically considers the effects of shifts in mean climate conditions. There is, however, some evidence of ongoing changes also in the variance of hydrologic and climate fluctuations. A relatively high interannual variability is a distinctive feature of the hydrologic regime of dryland regions, particularly at the desert ...

Hydrologic data collection over scales from centimemrs to continents, from minutes to years is difficult and expensive, so hydrologic models usually conceptualize processes based on simple, often homogeneous, views of nature. This forced oversimplification impedes cientific understanding and management of water resources. As the focus of hydrologic research shifts to larger regional and global ...

The basic principles underlying the most commonly used physically-based models of the rainfall-runoff transformation process are reviewed. A thorough knowledge of these principles is a pre-requisite for flood hazard studies and, thus, this chapter reviews several physically-based methods to determine flood discharges, flow depths, and other flood characteristics. The chapter starts with a thoro...

Hydrologic analyses are commonly based on a single conceptual model. Yet hydrologic environments are open and complex, rendering them prone to multiple interpretations and conceptualizations. Considering conceptual model uncertainty is a critical process for the assessment of hydrologic uncertainty. This study assesses recharge and geologic model uncertainty for the Climax Mine area of the Neva...

Ice-wedge polygons and related microtopographic variations are ubiquitous to landscapes underlain by permafrost. Highand low-centered polygons are typical but surprisingly, their role on hydrologic fluxes and stocks is not well quantified. We performed hydrologic modeling analyses using the physically-based model WaSiM-ETH that was forced by data from the Biocomplexity Experiment, Barrow, Alask...

Both local and large-scale processes affect the Amazon hydrologic cycle. We investigate the impact of deep soils on the atmosphere through local feedbacks. The Simple Biosphere model, version 3 (SiB3), is coupled to a single column model. Historically, land surface schemes parameterize soil moisture stress based on shallow soils and incorrectly capture seasonal cycles in the Amazon. Following o...

Emerging problems of environmental change and of long range hydrologic forecasting demand knowledge of the hydrologic cycle at global rather than catchment scale. Changes in atmosphere and/or landscape characteristics modify the earth's metabolism through changes in its biogeochemical cycles. The most basic of these is the water cycle which directly affects the global circulation of both atmosp...

Two instrumented test sections were constructed in summer 1999 at the Kiefer Landfill near Sacramento, California to test the hydraulic performance of two proposed alternative final covers. Both test sections simulated monolithic evapotranspiration (ET) designs that differed primarily in thickness. Both were seeded with a mix of two perennial and one annual grass species. Oleander seedlings wer...