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1.
The 33 086 ha mixed land use Fall Creek watershed in upstate New York is part of the Great Lakes drainage system. Results from more than 3500 water samples are available in a data set that compiles flow data and measurements of various water quality analytes collected between 1972 and 1995 in all seasons and under all flow regimes in Fall Creek and its tributaries. Data is freely accessible at https://ecommons.cornell.edu/handle/1813/8148 and includes measurements of suspended solids, pH, alkalinity, calcium, magnesium, potassium, sodium, chloride, nitrate nitrogen (NO3-N), sulphate sulphur (SO4-S), phosphorus (P) fractions molybdate reactive P (MRP) and total dissolved P (TDP), percent P in sediment, and ammonium nitrogen (NH4-N). Methods, sub-watershed areas, and coordinates for sampling sites are also included. The work represented in this data set has made important scientific contributions to understanding of hydrological and biogeochemical processes that influence loading in mixed use watersheds and that have an impact on algal productivity in receiving water bodies. In addition, the work has been foundational for important regulatory and management decisions in the region. 相似文献
2.
Water quality is often highly variable both in space and time, which poses challenges for modelling the more extreme concentrations. This study developed an alternative approach to predicting water quality quantiles at individual locations. We focused on river water quality data that were collected over 25 years, at 102 catchments across the State of Victoria, Australia. We analysed and modelled spatial patterns of the 10th, 25th, 50th, 75th and 90th percentiles of the concentrations of sediments, nutrients and salt, with six common constituents: total suspended solids (TSS), total phosphorus (TP), filterable reactive phosphorus (FRP), total Kjeldahl nitrogen (TKN), nitrate-nitrite (NOx), and electrical conductivity (EC). To predict the spatial variation of each quantile for each constituent, we developed statistical regression models and exhaustively searched through 50 catchment characteristics to identify the best set of predictors for that quantile. The models predict the spatial variation in individual quantiles of TSS, TKN and EC well (66%–96% spatial variation explained), while those for TP, FRP and NOx have lower performance (37%–73% spatial variation explained). The most common factors that influence the spatial variations of the different constituents and quantiles are: annual temperature, percentage of cropping land area in catchment and channel slope. The statistical models developed can be used to predict how low- and high-concentration quantiles change with landscape characteristics, and thus provide a useful tool for catchment managers to inform planning and policy making with changing climate and land use conditions. 相似文献
3.
Analytical study of ground motion caused by seismic wave propagation across faulted rock masses
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Studying seismic wave propagation across rock masses and the induced ground motion is an important topic, which receives considerable attention in design and construction of underground cavern/tunnel constructions and mining activities. The current study investigates wave propagation across a rock mass with one fault and the induced ground motion using a recursive approach. The rocks beside the fault are assumed as viscoelastic media with seismic quality factors, Qp and Qs. Two kinds of interactions between stress waves and a discontinuity and between stress waves and a free surface are analyzed, respectively. As the result of the wave superposition, the mathematical expressions for induced ground vibration are deduced. The proposed approach is then compared with the existing analysis for special cases. Finally, parametric studies are carried out, which includes the influences of fault stiffness, incident angle, and frequency of incident waves on the peak particle velocities of the ground motions. 相似文献
4.
Sdsealbedoisdefinedasaratioofreflectivesolarradiationtototalacradiation,whichcanindicatetheaborptionandreflectivecapabilityofthe~hforsolarradiation.Itisan~tfactortoinfluencethes~radiationbalance,espeiallyfortheformationandvariationoflocalndcroclirnate.Generally,theactualdatafromo~tionalstationSforrebationareedintheanalysisofsolacealal.HOwever,therepresentativenessOfthedateisIratedduetothescarcityofobservationalstationandunevendistributionofs~condition.Afterthe1960s,theanalysisfors~ealbedoise… 相似文献
5.
After the survey of pollution sources, a study on surface water quality assessment and forecast is given by means of grey
system method, fuzzy mathematical method and multiple-index method. Based on it, aquatic environment quality features, treatment
measures and environmental strategies of the area are proposed. The quality of aquatic environment of 5 rivers in the Tumen
River area is studied. The results show that the pollution of surface water is serious; water quality of most rivers is between
grade IV and V except the Hunchun River, being higher than grade IV standard; pollution levels of most rivers have been basically
controlled except the of Burhatong River, which is deteriorating gradually. Pollutants of the rivers are comparatively regular,
mainly are SS, COD, BOD, AR-OH, NH3-N. The main pollution trades are chemical fibre industry, pulp and paper making industry and mining industry. If the growth
rate of gross industrial product is higher than 25 percent under the encouraging-model of regional exploitation, the pollutants’
load will overtake the bearing capacity of aquatic environment. Thus some protection program against pollution must be worked
out in order to achieve the harmonious development of economy society and environment.
A project from “Studies on Earlier Stage of Regional Development” of the Chinese Academy of Sciences 相似文献
6.
The UV spectra of mixture solutions consisting of tyrosine,tryptophane,phenylalanine,cystine,histidineand 3,4-dihydroxyl phenylalanine have been measured.The numbers,identities and concentrations of theamino acids in the mixtures have been determined successfully using target factor analysis.The effectsof the wavelength range and the selected sampling interval on the results are discussed.Twenty-fivesynthetic mixture samples have been analysed successfully.The average recoveries are 98·9 for Tyr,96·5for Trp,105·6 for Phe,98·1 for Cys,98·9 for His and 106·4 for Di-phe.The results obtained are ingood agreement with those obtained by the Kalman filter method. 相似文献
7.
李新生 《地球科学与环境学报》1993,(Z2)
本文首先简述了斜坡演化过程与构造运动的关系,然后阐明了滑坡的空间分布、活动周期及活动规模与构造因素的联系。在此基础上指出:构造因素是滑坡产生的基础,对滑坡分布具宏观控制作用,并与滑坡的活动周期和活动规模密切相关,是滑坡研究及其灾害预测、预防研究工作中值得重视的重要因素。 相似文献
8.
In 1903 the Swiss Federal Research Institute WSL started its first forest hydrology measurements with the aim to deliver a sound scientific basis for the implementation of new forest legislation introduced in Switzerland in 1876. This legislation was triggered by several large floods that occurred in Switzerland, for which a major cause was widely seen as the poor condition of forests at that time. Consequently, hydrologic research at WSL first focused on the influence of forests on floods. In the second half of the 20th century, other hydrological issues such as water quality, snow hydrology and sediment transport complemented the hydrologic research at WSL. Some recent results of this work are presented in three papers joining this introductory paper to mark the 100th anniversary of hydrologic research at WSL. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
9.
Is Precipitation the Dominant Controlling Factor of High Inorganic Nitrogen Content in the Changjiang River and Its Mouth? 总被引:1,自引:1,他引:0
沈志良 《中国海洋湖沼学报》2003,21(4):368-376
The main reasons for the high content of inorganic N and its increase by several times in the Changjiang River and its mouth during the last 40 years were analysed in this work. The inorganic N in precipitation in the Changjiang River catchment mainly comes from gaseous loss of fertilizer N, N resulting from the increases of population and livestock, and from high temperature combustions of fossil fuels. N from precipitation is the first N source in the Changjiang River water and the only direct cause of high content of inorganic N in the Changjiang River and its mouth. The lost N in gaseous form and from agriculture non-point sources fertilizer comprised about 60% of annual consumption of fertilizer N in the Changjiang River catchment and were key factors controlling the high content of inorganic N in the Changjiang River mouth. The fate of the N in precipitation and other N sources in the Changjiang River catchment are also discussed in this paper. 相似文献
10.
Biogenic silicate accumulation in sediments, Jiaozhou Bay 总被引:1,自引:0,他引:1
1 INTRODUCTION Silicate, or silicic acid (H4SiO4), is a very im- portant nutrient in the ocean. Unlike other major nu- trients such as phosphate and nitrate or ammonium, which are needed by almost all marine plankton, silicate is an essential chemical req… 相似文献