{ "culture": "en-US", "name": "", "guid": "", "catalogPath": "", "snippet": "Bathymetric survey of Tom Paine Slough from 2013 and 2018. Both surveys included various along-axis profiles that sometimes overlapped. Nine cross sections were collected during both as well. The cross sections overlapped more closely than the profiles. However, accurate comparisons were challenging because of the often-low data density in 2013 and other possible sources of inaccuracy\n\nThe associated data are considered DWR enterprise GIS data, which meet all appropriate requirements of the DWR Spatial Data Standards, specifically the DWR Spatial Data Standard version 3.5, dated April 12, 2023. DWR makes no warranties or guarantees \u2014 either expressed or implied \u2014 as to the completeness, accuracy, or correctness of the data. DWR neither accepts nor assumes liability arising from or for any incorrect, incomplete, or misleading subject data. Comments, problems, improvements, updates, or suggestions should be forwarded to GIS@water.ca.gov.", "description": "

May 2013 - performed by Kjeldsen, Sinnock & Neudeck Inc. (KSN) at the request of Reclamation District 2058 to assess bed elevation change versus 2004 and 2005 DWR surveys. The KSN survey consisted one single-beam sonar along-axis profile that included direct GPS observation points through the non-navigable, weed-filled eastern reach of the slough (starting at about cross section 8). The nine cross sections were surveyed with direct GPS observations of limited data density due to the method used.<\/SPAN><\/SPAN><\/P>

January 2018 \u2013 performed by DWR, North Central Region Office at the request of Bay Delta Office to assess channel elevations. This survey was intended to fully cover the target area with three along-axis profiles and the nine cross sections. All data was collected with sonar.<\/SPAN><\/SPAN><\/P>

The 2013 KSN dataset was very sparse in areas, with as much as 125 feet separating points along the profile, on average, and as few as five observations within the channel banks for cross sections. The 2018 DWR survey had much improved data density, but the comparison is necessarily limited by the availability of data from 2013. An estimate of bed elevation change in Tom Paine Slough along the centerline was made by subtracting 2013 elevation from calculated 2018 elevation for points that were within a 5-foot radius of one another according to an algorithm calculating the weighted average of nearest neighbor points (WANN). Change for the cross sections was analyzed separately. No attempt was made to produce an estimate of change for the whole of Tom Paine Slough because the data from 2013 only contained one centerline and the cross sections were too far apart to reasonably interpolate a surface. Change along the 2013 centerline was further broken down by 3,000 foot segments along the profile to examine change more locally. To prevent under-weighting areas with fewer qualifying data points, all statistics were calculated on an evenly-spaced dataset, with change in elevation interpolated to one foot intervals. Analysis of change along the centerline indicates a small, but significant, net deposition of sediment in Tom Paine Slough between 2013 and 2018. Sediment trends vary locally and are sensitive to differences in boat path 1, but suggest increasing deposition from west to east, with a short reach of scour near cross section 7. Since accuracy for two surveys was 0.24 ft and 0.16 ft for KSN and DWR, respectively, as much as 0.4 ft of difference could be explained by systematic survey error. However, this does not explain the increasing trend of deposition along Tom Paine Slough. The difference in data collection methods used by KSN \u2014 sonar for most of the slough, with direct GPS observation in weedy areas \u2014 could also be responsible for some of the increase seen towards the eastern end of the survey. There was a much higher mean elevation change for KSN points collected by direct observation (1.1 ft) compared to points collected by sonar (0.6 ft). Despite this, it is entirely possible that this observed difference between collection techniques was caused by an actual trend in deposition. It appears most likely that both are true: some of the increase in elevation towards the east is due to differing collection techniques, but most of it probably reflects an actual increase in elevation. Mean change in elevation and change in cross-sectional area was calculated for each individual cross section. Because the 2013 KSN cross sections were all conducted by labor intensive manual GPS observations, data points within the channel were sparse, but land elevations beyond the channel banks were included. The 2018 DWR survey was conducted by sonar within the navigable channel limits, and thus had much greater data density within the channel, but without land elevations beyond the banks.<\/SPAN><\/SPAN><\/P><\/DIV><\/DIV><\/DIV>", "summary": "Bathymetric survey of Tom Paine Slough from 2013 and 2018. Both surveys included various along-axis profiles that sometimes overlapped. Nine cross sections were collected during both as well. The cross sections overlapped more closely than the profiles. However, accurate comparisons were challenging because of the often-low data density in 2013 and other possible sources of inaccuracy\n\nThe associated data are considered DWR enterprise GIS data, which meet all appropriate requirements of the DWR Spatial Data Standards, specifically the DWR Spatial Data Standard version 3.5, dated April 12, 2023. DWR makes no warranties or guarantees \u2014 either expressed or implied \u2014 as to the completeness, accuracy, or correctness of the data. DWR neither accepts nor assumes liability arising from or for any incorrect, incomplete, or misleading subject data. Comments, problems, improvements, updates, or suggestions should be forwarded to GIS@water.ca.gov.", "title": "i06_Bathy_NCRO_20180621_TomPaineSlough", "tags": [ "Elevation", "ISO 006", "Bathymetry", "Sacramento", "San Joaquin Delta", "Walnut Grove", "Ryde", "Slough", "June", "2018", "Single Beam", "Tom Plaine Slough", "DWR GIS Atlas" ], "type": "", "typeKeywords": [], "thumbnail": "", "url": "", "minScale": 150000000, "maxScale": 5000, "spatialReference": "", "accessInformation": "California Department of Water Resources (DWR), North Central Region Office (NCRO).", "licenseInfo": "

Not for use as a navigation aid. The data reflects measurements taken at specific time periods and the Department of Water Resources makes no claim as to the current state of these waterways. Do not share or publish this data without including proper attribution.<\/SPAN><\/P><\/DIV><\/DIV><\/DIV>", "portalUrl": "" }