scholarly journals LONG-TERM FIELD OBSERVATION AND APPLICATION OF WEPP MODEL FOR SEDIMENT YIELD AND TRANSPORT IN NAGURA WATERSHED

2008 ◽  
Vol 52 ◽  
pp. 577-582 ◽  
Author(s):  
Kazutoshi OSAWA ◽  
Syunsuke IKEDA ◽  
Ryuzaburo KUBOTA ◽  
Keigo NODA ◽  
Yoshihisa AKAMATSU
Keyword(s):  
Sediment Yield ◽  
Field Observation ◽  
Term Field

SIMULATION OF NITRIFICATION AND DENITRIFICATION PROCESSES IN A TIDAL RIVER

1994 ◽  
Vol 30 (2) ◽  
pp. 43-52 ◽  
Author(s):  
Tetsuya Kusuda ◽  
Tohru Futawatari ◽  
Kyoko Oishi
Keyword(s):  
Water Quality ◽  
Field Observation ◽  
Tidal River ◽  
Sediment Surface ◽  
Water Volume ◽  
Water Quality Control ◽  
Laboratory Test Results ◽  
Nitrification And Denitrification ◽  
Term Field

Nitrification and denitrification processes in a well mixed tidal river in Japan are modeled, based on results of long term field observation on water quality and sediments in the river. Laboratory test results and values in references are used for the determination of parameters and coefficients in the model. In modeling of the processes, sediments, suspended solids, and overlying water are taken as elements and in computation a Lagrangian reference frame in terms of accumulated water volume is employed for reduction in numerical dispersion. Simulation results on ammonium and nitrate nitrogen, showing good agreement with long term field observation results, qualitatively explain well the processes in the river. The results indicate some countermeasures to reduce nitrate more such as the increase in the area of sediment surface. The simulation model is available for the estimation of water quality in well mixed tidal rivers and applicable for water quality control.

Long Term Field Test Results of Experimental EPDM and PUF Roofing

1990 ◽  
Author(s):  
David M. Bailey ◽  
Stuart D. Foltz ◽  
Myer J. Rosenfield
Keyword(s):  
Field Test ◽  
Test Results ◽  
Term Field

scholarly journals Soil erosion by snow gliding – a first quantification attempt in a subalpine area in Switzerland

2014 ◽  
Vol 18 (9) ◽  
pp. 3763-3775 ◽  
Author(s):  
K. Meusburger ◽  
G. Leitinger ◽  
L. Mabit ◽  
M. H. Mueller ◽  
A. Walter ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Sediment Yield ◽  
Soil Loss ◽  
Water Erosion ◽  
Erosion Rates ◽  
The Difference ◽  
Snow Gliding

Abstract. Snow processes might be one important driver of soil erosion in Alpine grasslands and thus the unknown variable when erosion modelling is attempted. The aim of this study is to assess the importance of snow gliding as a soil erosion agent for four different land use/land cover types in a subalpine area in Switzerland. We used three different approaches to estimate soil erosion rates: sediment yield measurements in snow glide depositions, the fallout radionuclide 137Cs and modelling with the Revised Universal Soil Loss Equation (RUSLE). RUSLE permits the evaluation of soil loss by water erosion, the 137Cs method integrates soil loss due to all erosion agents involved, and the measurement of snow glide deposition sediment yield can be directly related to snow-glide-induced erosion. Further, cumulative snow glide distance was measured for the sites in the winter of 2009/2010 and modelled for the surrounding area and long-term average winter precipitation (1959–2010) with the spatial snow glide model (SSGM). Measured snow glide distance confirmed the presence of snow gliding and ranged from 2 to 189 cm, with lower values on the north-facing slopes. We observed a reduction of snow glide distance with increasing surface roughness of the vegetation, which is an important information with respect to conservation planning and expected and ongoing land use changes in the Alps. Snow glide erosion estimated from the snow glide depositions was highly variable with values ranging from 0.03 to 22.9 t ha−1 yr−1 in the winter of 2012/2013. For sites affected by snow glide deposition, a mean erosion rate of 8.4 t ha−1 yr−1 was found. The difference in long-term erosion rates determined with RUSLE and 137Cs confirms the constant influence of snow-glide-induced erosion, since a large difference (lower proportion of water erosion compared to total net erosion) was observed for sites with high snow glide rates and vice versa. Moreover, the difference between RUSLE and 137Cs erosion rates was related to the measured snow glide distance (R2 = 0.64; p < 0.005) and to the snow deposition sediment yields (R2 = 0.39; p = 0.13). The SSGM reproduced the relative difference of the measured snow glide values under different land uses and land cover types. The resulting map highlighted the relevance of snow gliding for large parts of the investigated area. Based on these results, we conclude that snow gliding appears to be a crucial and non-negligible process impacting soil erosion patterns and magnitude in subalpine areas with similar topographic and climatic conditions.

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