do.usbr. Summary We investigate the applicability of the Two-dimensional, Runoff, Erosion and Export (TREX) model to simulate extreme floods on large watersheds in semi-arid regions in the western United States. Spatially-distributed extreme storm and channel components are implemented so that the TREX model can be applied to this problem. TREX is demonstrated via calibration, validation and si...

The method is applied to North Rhine-Westphalia (Western Germany) using the FOOT3DK mesoscale model for dynamical downscaling and ECHAM5/OM1 global circulation model climate projections. The method first classifies typical weather developments within the reanalysis period using K-means cluster algorithm. Most historical wind storms are associated with four weather developments (primary storm-cl...

A mathematical and statistical model for simulating contaminant removal from a surface sand filter is reported. The model was based on a mass balance equation and an advection-dispersion transport model. The unknown parameters of the model were the deposition rate and the hydrodynamic dispersion. Changes in space were allowed within the filter media depth and time variability of flow and influe...

We have modeled atmospheric effects, especially ozone depletion, due to a solar proton event which probably accompanied the extreme magnetic storm of 1-2 September 1859. We use an inferred proton fluence for this event as estimated from nitrate levels in Greenland ice cores. We present results showing production of odd nitrogen compounds and their impact on ozone. We also compute rainout of nit...

abstract researches of preservation valuation of natural resources and environment were done in order to create necessary awareness for making optimal decisions in the field of the ways of economic management of these resources and helping to establish sustainable regional development strategy. in this study, preservation value of lilium ledebourii estimated using single bounded dichotomous cho...

Monitoring programs for urban runoff have not been assessed for effectiveness or efficiency in estimating mass emissions. In order to determine appropriate designs for stormwater, total suspended solids (TSS) and flow information from the Santa Ana River was collected nearly every 15 min for every storm of the 1998 water year. All samples were used to calculate the "true load" and then three wi...