Estimating ground water discharge by hydrograph separation     

Hannula SR  Esposito KJ  Chermak JA  Runnells DD  Keith DC  Hall LE 《Ground water》2003,41(3):368-375

Iron Mountain is located in the West Shasta Mining District in California. An investigation of the generation of acid rock drainage and metals loading to Boulder Creek at Iron Mountain was conducted. As part of that investigation, a hydrograph separation technique was used to determine the contribution of ground water to total flow in Boulder Creek. During high-flow storm events in the winter months, peak flow in Boulder Creek can exceed 22.7 m3/sec, and comprises surface runoff, interflow, and ground water discharge. A hydrograph separation technique was used to estimate ground water discharge into Boulder Creek during high-flow conditions. Total ground water discharge to the creek approaches 0.31 m3/sec during the high-flow season. The hydrograph separation technique combined with an extensive field data set provided reasonable estimates of ground water discharge. These estimates are useful for other investigations, such as determining a corresponding metals load from the metal-rich ground water found at Iron Mountain and thus contributing to remedial alternatives.  相似文献   

Response to comments on an article entitled 'A geochemical survey of spring water from the main Ethiopian rift valley,southern Ethiopia: implications for well-head protection' by McKenzie et al., Hydrogeology Journal (2001) 9:265–272     

Jeffrey?M.?McKenzieEmail author  Donald?I.?Siegel  D.?Jonathan?McKenzie 《Hydrogeology Journal》2003,11(2):316-317

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Radio emission observed by Galileo in the inner Jovian magnetosphere during orbit A-34     

J. Douglas Menietti  Donald A. Gurnett  Joseph B. Groene 《Planetary and Space Science》2005,53(12):1234-1242

The Galileo spacecraft encountered the inner magnetosphere of Jupiter on its way to a flyby of Amalthea on November 5, 2002. During this encounter, the spacecraft observed distinct spin modulation of plasma wave emissions. The modulations occurred in the frequency range from a few hundred hertz to a few hundred kilohertz and probably include at least two distinct wave modes. Assuming transverse EM radiation, we have used the swept-frequency receivers of the electric dipole antenna to determine the direction to the source of these emissions. Additionally, with knowledge of the magnetic field some constraints are placed on the wave mode of the emission based on a comparative analysis of the wave power versus spin phase of the different emissions. The emission appears in several bands separated by attenuation lanes. The analysis indicates that the lanes are probably due to blockage of the freely propagating emission by high density regions of the Io torus near the magnetic equator. Radio emission at lower frequencies (<40 kHz) appears to emanate from sources at high latitude and is not attenuated. Emission at is consistent with O-mode and Z-mode. Lower frequency emissions could be a mixture of O-mode, Z-mode and whistler mode. Emission for shows bands that are similar to upper hybrid resonance bands observed near the terrestrial plasmapause, and also elsewhere in Jovian magnetosphere. Based on the observations and knowledge of similar terrestrial emissions, we hypothesize that radio emission results from mode conversion near the strong density gradient of the inner radius of the cold plasma torus, similar to the generation of nKOM and continuum emission observed in the outer Jovian magnetosphere and in the terrestrial magnetosphere from source regions near the plasmapause.  相似文献   

THE EFFECT OF CADMIUM AND CHROMIUM ON TWO POPULATIONS OF THE POLYCHAETOUS ANNELID CAPITELLA CAPITATA     

Donald J. Reish 《中国海洋湖沼学报》1983,1(3):337-341

Bioassays are important laboratory experiments in an attempt to interprete what is occurring in the field. The effect of various potential pollutants, especially heavy metals, on marine organisms has resulted in many studies in recent years. Polychaetous annelids have been one of the more commonly used test organisms because of their importance in the marine environment. Interlaboratory experiments have been conducted using the polychaetes Capitella capitata and Neanthes arenaceodentata (Pesch and Hoffman, in press) in which  相似文献   

HYDROLOGIC MANAGEMENT IN BALI     

W. Donald McTaggart  Ph.D. 《Singapore journal of tropical geography》1989,9(2):96-111

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Meeting reports     

M. I. El-Sabh  T. S. Murty  Donald J. Goralski 《Natural Hazards》1989,2(2):185-191

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‘Truth or Consequences’ for the practicing hydrologist: on scientific certainty and ethics     

Donald I. Siegel 《水文研究》2001,15(3):521-523

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Comment on: “The photolytic stability of the Martian atmosphere” by R. C. Whitten and J.S. Sims     

Donald M. Hunten 《Planetary and Space Science》1974,22(5):878-879

It is pointed out that the models given contain internal contradictions: they produce more O₂ than they destroy by factors of 100 or more.  相似文献   

The occultation of Mariner 10 by Mercury     

Gunnar Fjeldbo  Arvydas Kliore  Donald Sweetnam  Pasquale Esposito  Boris Seidel  Taylor Howard 《Icarus》1976,29(4):439-444

An analysis of the Mariner 10 dual frequency radio occultation recordings has yielded new information on the radius and atmosphere of Mercury. The ingress measurements which were conducted near 1.1° North latitude and 67.4° East longitude on the night side of the planet, gave a value for the radius of 2439.5 ± 1 km. Egress near 67.6° North latitide and 258.4° East longitude in the sunlit side yielded a radius of 2439.0 ± 1 km. The atmospheric measurements showed the electron density to be less than 10³ cm^?3 on both sides of the planet. From the latter result one may infer an upper limit to the dayside surface gas density of 10⁶ molecules per cm³.  相似文献   

Comparison of calculational approaches for structural deformation in jointed rock     

Paul E. Senseny  Donald A. Simons 《国际地质力学数值与分析法杂志》1994,18(5):327-344

Results from five different computer models for structural deformation in jointed rock are compared for a problem involving stress-wave loading of a lined circular tunnel in a jointed medium. The computer models include two discrete element codes, The Direct Interacting Block Systems (DIBS) and The Universal Distinct Element Code (UDEC), and three finite element codes, The Finite Element Code for Largely Explicit Calculation (FLEX), The Explicit Calculations of Interacting Bodies Under Rapid Loading Code (EXCALIBUR), and PRONTO. The finite element codes used either slidelines or joint elements to simulate the motion on joints. All codes had some difficulties with a sequence of preliminary problems solved to ‘shake down’ the computer codes. However, most of the shortcomings of each code were readily overcome. Results showed that three codes could obtain similar answers for tunnel closure, stress around the tunnel and slip on the joints.  相似文献