Hydrography of the Russian River Estuary - Sonoma County Water ...

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• Instrument precision The error associated with each of these terms is quantified for different inlet conditions, taking a worst-case scenario (i.e., conditions that would produce the worst possible error). Thus, this error analysis does not quantify actual error but rather seeks an upper bound to the possible error in calculating salt and oxygen masses. Section uniformity errors – The vertical distribution of salinity and dissolved oxygen in the water column is not entirely uniform throughout the estuary, even during closure. CTD profiles taken at the locations shown in Figure 2.1 may not be representative of the average vertical profile in each segment of the estuary. A fully accurate budget would require CTD profiles at many locations within each segment of the estuary, which is not feasible. The segmentation of the estuary shown in Figure 3.37 was chosen to provide reasonable accuracy while balancing time constraints. To obtain a quantitative estimate of the errors that this simplification creates, the profile in the segment was compared with the average of the profiles from the 2 adjacent segments. Tables 3.2 and 3.3 show that the total masses obtained using these average profiles differ from those from the actual CTD profiles by 1.0-8.1 percent for salt and 0.9-6.9 percent for dissolved oxygen. Elevation estimate errors – Since water level elevations were normalized to the Jenner gage, rather than tied to known coordinates using survey equipment, reported water levels may be inaccurate by several centimeters (see discussion in Section 2). Inaccuracies in water level cause misalignments between the stage-storage curve for each segment of the estuary and the corresponding CTD profiles. Assuming that water level estimates are accurate to within ± 5cm, these errors are below 3%, regardless of inlet condition (Tables 3.2 and 3.3). Pycnocline tilt errors – During high wind conditions, the surface of the estuary was observed to tilt by as much as 5cm in the upstream direction. A corresponding tilt (in the reverse direction) of the subsurface pycnocline is expected to be much larger and it would temporarily make the outer estuary saltier and the inner estuary fresher. Errors would arise if the tilt is non-uniform, or if the number of profiling locations is insufficient to determine its shape. The order of these errors was obtained by comparing masses estimated with a tilted pycnocline to those estimated during low-wind conditions. The maximum water surface tilt observed during CTD measurements was 2cm, which would result in a tilt of the pycnocline of about 0.8 meters (2.6 feet), estimated from the ratio between ρ and Δρ (Fischer et al. 1979). Errors for both total estuary salt and oxygen mass are below 7%, and are highest for most strongly stratified conditions (Tables 3.2 and 3.3). Most CTD measurements were taken during low wind conditions, so these results are intended to illustrate the maximum possible error observed in the data. 64
Bathymetry resolution errors – The resolution of the raster used to represent the bathymetry of the estuary may alter the budgets by influencing the stage-storage curve for each estuary segment. A 10m x10m raster was used as a simplification of the bathymetry data. It is difficult to assess the increase in accuracy that would be achieved by increasing this resolution, but the errors from this source are assumed to be small, since boundary cells make up a very small proportion of the estuary bathymetry even at this scale. Instrument precision errors – CTD precision errors for salinity and dissolved oxygen measurements are very low compared to the other error sources, and are neglected. The maximum possible error for the salt budget appears to be 13.7% and 12.5% for the oxygen budget. Actual errors are expected to be much smaller than this and to have no influence on the overall trends identified in the above sections on salt and oxygen budgets. Table 3.2. Error estimates for estuary salt budget Inlet condition, date Salt mass (10 6 kg) Nonuniform segment conditions Error estimates (%) ± 5cm elevation error 0.8m (2.6ft) Pycnocline tilt Total error (%) Tidal Aug 11 77 1.0 2.5 0.1 3.6 Oct 7 73 3.4 2.3 2.4 8.1 Muted Sep 1 53 5.6 2.7 1.6 9.9 tidal Sep 2 55 8.1 2.7 2.9 13.7 Close d inlet Sep 15 56 1.4 2.7 6.4 10.5 Sep 26 47 2.7 3.0 6.9 12.6 Oct 5 35 1.0 3.0 6.3 10.3 65
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HYDROGRAPHY OF THE RUSSIAN RIVER ES
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Executive Summary Circulation, stra
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Table of Contents 1. Introduction .
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1. Introduction The Russian River B
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The study was conducted from June t
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attached to each ADCP, and a third
Page 13 and 14: 3. Data Analysis The results from s
Page 15 and 16: existing SCWA-management protocol t
Page 17 and 18: 7. Loss to aquifers: This term quan
Page 19 and 20: Figure 3.7). A concurrent drop in e
Page 21 and 22: Histograms of the probability of fl
Page 23 and 24: Figure 3.8. Observed flow losses du
Page 25 and 26: easily over denser estuarine waters
Page 27 and 28: 3.2.2 - Current velocities at Heron
Page 29 and 30: Figure 3.14. Water levels (top pane
Page 31 and 32: This diurnal cycle in winds results
Page 33 and 34: Figure 3.18. Observed water levels
Page 35 and 36: All water properties are subject to
Page 37 and 38: 3.3.2 - Salt intrusion into inner e
Page 39 and 40: Figure 3.22. Water temperatures dur
Page 41 and 42: On closer inspection, one can see t
Page 43 and 44: Preliminary biochemical oxygen dema
Page 45 and 46: 3.4 - Stratification and water-colu
Page 47 and 48: Figure 3.29. Profiles of density, v
Page 49 and 50: diurnal variations during the sprin
Page 51: Using CTD profiles of ρ(z), time-s
Page 54 and 55: Figure 3.36. Decreasing bottom sali
Page 56 and 57: Figure 3.37. Estuary bathymetry fro
Page 58 and 59: water) or it may reflect vertical m
Page 60 and 61: Figure 3.40. Nearshore wave height,
Page 62 and 63: Figure 3.41. Change in dissolved ox
Page 66 and 67: Table 3.3. Error estimates for estu
Page 68 and 69: unaffected and remains resident for
Page 70 and 71: 5. Literature Reviewed Battalio, B.
Page 72: Simpson, J., J. Brown, J. Matthews,
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