Flowpath

Double pass A split-flow tray with two liquid flowpaths on each tray. Each path handles half of the total liquid flow. 

The processes through which rainfall is turned into runoff, together with the nature of the material through which water moves, control the chemical characteristics of streamflow. Specific runoff mechanisms operating in a landscape control the flowpaths by which water moves through the landscape. Flowpath-depen-dent differences, such as the total time that water spends in contact with different soil horizons or bedrock (residence time), can strongly influence runoff amounts and timing, the relative contribution of event (new) versus stored (old) water, and runoff chemistry. 

The combined influences of runoff generation mechanisms, runoff flowpaths, and soil properties together control runoff chemistry. In spite of the wide range of interactions that characterize terrestrial environments, a few broad generalities can be offered, as the chemical composition of streamflow typically contains... 

Fisher SG, Sponseller RA, Heffeman JB (2004) Horizons in stream biogeochemistry flowpaths to progress. Ecology 85 2369-2379... 

Hydrologic flowpath Short-circuited Shallow Deep N/A... 

Sensitive sites would include sites that are receiving high inputs of atmospheric Hg deposition and sites with aquatic ecosystems where top end predators have high levels of Hg. We also recommend that urban sites with elevated atmospheric Hg deposition and forest sites with shallow hydrologic flowpaths, wetlands, and unproductive aquatic ecosystems should strongly be considered as candidate sites. 

Figure 8 shows basic elements of a feedback control system as represented by a block diagram. The functional relationships between these elements are easily seen. An important factor to remember is that the block diagram represents flowpaths of control signals, but does not represent flow of energy through the system or process. 

Fig. 4. Diagram of the numerous possible environmental flowpaths of humic substances...

Bullen TD, Kendall C (1998) Tracing of weathering reactions and water flowpaths a multi-isotope approach. Iir. Isotope Tracers in Catchment Elydrology Kendall, McDonnell JD (eds) Elsevier Science, Amsterdam, p 611-646... 

The initial and final waters used in these simulations were selected from among the analyses listed in Table 7. Although a number of simulations were made for various different flowpaths deemed likely on the basis of the hydrogeological model, the presentation here is restricted solely to investigations of the evolution of the mature pumped waters at Whittle Drift Borehole (Fig. 6) from a range of possible precursor waters. The mature Whittle Drift pumped water is of Ca- Na SC)4 facies, with a pH around 7.5 and <45 mg/L dissolved Fe. The possible precursor waters were identified as follows ... 

Figure 14.3 Variation in concentrations of important dissolved redox species along the flowpath of a contaminant plume in ground-water. This sequence results in several zones of characteristic microbial metabolism and corresponding redox conditions (adapted from Bouwer et al., 1984).

Flow of fluid through porous medium" (Darcy s Law, see Eq. 25-5) n i 8 = q (m s 1) h (m) Kq (m s 1) Discharge per area Hydraulic head (pressure change along flowpath x) Hydraulic conductivity of medium... 

When aquifers were amended with nitrate in order to stimulate biodegradation, the results were generally consistent with those obtained in laboratory investigations. In a field injection experiment at Seal Beach, California, Ball et al. (1994) demonstrated complete removal of w-xylene and the m-,/-xylene fraction decreased significantly in parallel bioreactor experiments. A Canadian study showed a decrease in m- and /-xylene of 14% and 15%, respectively, over aim flowpath in the Borden aquifer (Barbara et al., 1992). Very little degradation was observed beyond that point, presumably due to the availability of preferred electron donors in the landfill leachate impacted aquifer. 

CNG dispensers typically incorporate stainless steel for the flowpath of the natural gas, and no materials compatibility problems are likely. CNG dispensers do not typically incorporate filters—if filtering is deemed necessary, it is usually done at the outlet of the compressor before the CNG enters the storage system. 

Control of an interface for the selection of the flowpath and the positioning of the peaks in the system. 

There have been a number of regional analyses showing that stream and river DOC concentrations appear to be highly influenced by the flowpath of water across the landscape. Streams draining landscapes dominated by water flowpaths at the land surface in contact with organic-rich soil horizons... 

Water flowpath through soil is also an important determinant of variations in DOC concentration over time within individual streams. In well-drained catchments numerous studies have shown that stream DOC... 

Hinton, M. J., S. L. Schiff, and M. C. English. 1998. Sources and flowpaths of dissolved organic carbon during storms in two forested watersheds of the Precambrian Shield. Biogeochemistry 41 175—197. 

Findlay, S., J. M. Quinn, C. W. Hickey, G. Burrell, and M. Downes. 2001. Effects of land-use and riparian flowpath on delivery of dissolved organic carbon to streams. Limnology and Oceanography 46 345—355. 

Tindall, J. A. and W.K. Vencill (1995). Transport of atrazine, 2,4-D, and dicamba through preferential flowpaths in an unsaturated claypan soil near Centralia, Missouri. J. Hydrol., 166 37-59. 

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