Water Depth Determination

In areas where detailed bathymetry is required, a precise multibeam echo soimder may be used. There are many considerations when evaluating such a system, such as the vertical accuracy, resolution, acoustic beamwidth of the transmit/receive beam, and the acoustic frequency of the transducer. Most hydrographic echo sounders are dual frequency, that is, they have a low-frequency pulse (typically aroimd 24 kHz) that can be transmitted at 

Towed devices for geophysical surveys. (From Sullivan, R.A., Marine Geotech., 4, 1-30, 1980. Reprinted with permission of Taylor Francis Group.) 

The speed of sound in water and sediments is assmned to be the same and constant. In reality, this is never true however, assuming it is true is good for a first approximation for shallow subbottom depths. Most recorders are set assimiing a sound speed of 1.5 km/s. If more accuracy is needed, you can refer fo Matthew s tables (1927) for water and Hamilton (1974) for sediments. Most charted ocean depths are based on echo sounding, which use an average or standard seawater sound speeds. 

---

Enter failure probabilities (ones) in the system model to determine the plant damage states as a function of water depth... 

Cotton paper (100%) obtained from Mead Corporation in South Lee, Massachusetts, was pulped at Krofta Engineering Corporation (KEC), Lenox, MA.59 A known amount of pulp was suspended in tap water to determine the percent recovery by a circular DAF cell (Model Supracell Type 3 diameter = 0.91 m [3 ft] depth = 55.88 cm [22 in.] flow = 45L/min [12gal/min]). The initial total... 

The expressions in Table 4.7 show that sewer systems and flow characteristics determine the magnitude of KLa. Figure 4.5 illustrates how K,a varies with the flow in a gravity sewer with a diameter D = 0.7 m and a slope s = 0.003 at a temperature of 15°C. The figure also depicts the corresponding water depth-to-diameter ratio (y/D) and a full-flowing pipe at about 530 m3 h 1 (1471 s-1). 

This stratified estuary has a depth of 40 m, with an upper fresh or brackish water layer of 0.2-4 m, depending on the river flow. The main source of pollution is untreated municipal wastewater, which is discharged into the estuary. Water samples were collected at different distances from these sewage outlets at two water depths from the fresh and the marine water layers. Furthermore, at one location, a vertical profile of the water column was made, including a sample of the water surface micro layer. Total A9PEOn, and individual AgPEOi, A9PEO2 and NP concentrations were determined with normal phase HPLC-FL analysis. 

Some particles, particularly the biogenous ones, are prone to alteration as they settle onto the sediments and then imdergo burial. The likelihood of particle preservation is generally enhanced in settings where the trip to the seafloor is short and burial rates are fast. The time a particle takes to settle onto the seafloor is determined by water depth and particle sinking rates. The latter is a function of particle shape and density. Seawater... 

To determine the H202 decay rate correlated with depth, two locations were studied station 212 in Lake Ontario and Station 23 in Lake Erie. At both sampling locations the rate decreased with depth (i.e., the H202 half-life increased. For example, at station 212, the tm increased from 14.7 h in the surface-water sample to 21.6 h in the sample obtained at 10 m. At station 23 the surface tm was 9.6 h, and it increased to 20.2 h in the sample from a water depth of 16.4 m. 

Evidently, if the value of dy/dx as determined by Eq. (10.128) is positive, the water depth will be increasing along the channel if negative, it will be decreasing. Looking first at the numerator, S may be considered as the slope, such as would be obtained from Eq. (10.124), which would carry the given discharge at depth y with uniform flow. Let y0 denote the depth for uniform flow on the bed slope S0- Then, by Eq. (10.125), written for the unit width flow,... 

The problem of determining where a hydraulic jump will occur is a combined application. In the case of supercritical flow on a mild slope, for instance, the tail water depth y2 is determined by the uniform flow depth jo for that slope. The rate of flow and the application of Eq. (10.133) then fix yu and the length of the M3 curve required to reach this depth from the upstream control may be computed from Eq. (10.123). Similarly, in the case of subcritical flow on a steep slope, the initial depth is equal to y0, the tail water depth is given by Eq. (10.133), and the length of the Si curve to the jump from the downstream control is computed from Eq. (10.123). For application of the hydraulic jump to design problems, and for analysis of the jump in circular and other nonrectangular sections, the reader is referred to more extensive treatises on the subject [42],... 

Langhorne, D.N. (1977) Consideration of meteorological conditions when determining the navigational water depth over a sand wave field. Inti. Hydrogr. Rev. LIV, 17-30. 

At this time it is not possible to make an accurate estimate of the absolute uncertainty in the situ values of the apparent solubility constants for calcite and aragonite. An approximate maximum uncertainty can be determined for at 5000 m water depth and 2°C by using two different data sets. The maximum value for is obtained by using value and temperature coefficient calculated by Berner (26) and the effect of pressure of Ingle (32). The value for obtained by this method is 19.8 X 10" mole kg . The minimum value is obtained by using the v ue and temperature coefficient of Ingle. (25),... 

Figure 6.13 Relative rate of N2 production from anammox as a percentage of the total N2 production rate as determined from incubation experiments described in text. Although the relative rate of anammox increases with water depth, the ablsolute rate of N2 production generally decreases with increasing water depth. (Redrawn from Dalsgaard etal, 2005).

Chemicals may be removed from some aquatic environments by volatilization. The intrinsic potential for volatilization is determined by the Henry s Law constant (H) of the substance. Volatilization from the aquatic environment is highly dependent on the environmental conditions of the specific water body in question, such as the water depth, the gas exchange coefficients (depending on wind speed and water flow) and stratification of the water body. Because volatilization only represents removal of a chemical from water phase, the Henry s Law constant caimot be used for assessment of degradation in relation to aquatic hazard classification of substances. Substances that are gases at ambient temperature may however for example be considered further in this regard (see also Pedersen et al, 1995). 

Figure 4 Variations in of total OC (left axis %o, open circles) and the abundance of lignin-derived syringyl and vanillyl phenols (right axis A, mg per 100 mg OC, triangles) in surface sediments from various water depths of the Gulf of Mexico in the vicinity of the outflow from the Mississippi River system (after Goni et aL, 1997 Also shown are average values for the same parameters determined on suspended particulate matter from the upper and lower reaches of the Mississippi River (extreme left column, error bars = 1 SD data from Onstad et ai, 2000). In addition, values are indicated for one lignin phenol (syringic acid filled circles), for selected shelf and slope...

Figure 21 Comparison of vertical distribution of biomarker and microbial abundances in oceanic water columns, (a) Contour plots of concentration (ngL ) of hexadecanoic acid, (b) Crenarcheol at various depths in the water column and distances from shore on a northwest-to-southeast transect off Oman in the Arabian Sea (after Sinninghe Damste et al, 2002). Hexadecanoic acid serves as a biomarker proxy for eukaryotic and bacterial biomass and clearly shows the expected surface maximum, with concentrations dropping off steeply with increasing water depth. In contrast, crenarcheol, a molecular biomarker for planktonic crenarcheota, shows two maxima with one near 50 m and the other —500 m. (c) Vertical distributions of microbial concentrations in the North Pacific subtropical gyre bacteria (solid squares) and planktonic crenarcheota (open squares). Effectively, there are two microbial domains which were determined using a DAPI nucleic acid stain (after Karner et al., 2001). These data show the increasing proportion of planktonic archea in deep waters, with the result that at depths greater than 2,000 m, the crenarcheota are as abundant...

Measnre the water depth in the above container so that the depth of the Petri dish can be determined. 

The sulfate reducers, mainly Desulfovibrio spp. and Desulfotomaculum spp., are heterotrophs and the amount of utilizable organic matter determines their activity. The activity of sulfate-reducing organisms is generally rather low and will vary with water depth as verified by investigations in the Black Sea (Sorokin, 1964). Sorokin found that in the shallow... 

The specific dissipation due to wave power is strongly dependent on water depth and, therefore, will have sharply defined bounds in most estuaries. It Is determined by the depth, the available fetch, and the intensity of the winds having sufficient duration to raise a fully developed sea. For Long Island Sound the wave-dominated zone is that in water shallower than 18 m this constitutes 54% of the total area of the Sound. Within the wave-dominated zone the particle motion due to waves at the water surface is more effective in exciting sediment from the bottom than other causes of water movement. Large quantities of sediment may be set in motion by the waves and relatively small currents can then effect substantial transport of the material so excited. An example of an estuary in which wave-excited sediment is an important fraction of the total sediment available for estuarine processes is the Tay, where wave erosion followed by overland flow on bare mudflats exposed on the ebb of the tide results in large sediment concentrations in the water of the estuary (Buller et al., 1975). 

The latter should be directly related to the depth of water and salinity, which together determine the total production rate of from Instead, the h inventory (limited mainly to the top 5 cm of the sediment pile) is largely determined by the amount of fine-grained component present at each location, and this fine-grained component is homogenized over the range of water depths on a time scale rapid compared with the half-life of n h (24 days). 

---