JUNE 2015

Appendix B: Groundwater Levels, Borehole Lithological Data, and Thickness of Organic Soils and Mud Deposits Steven J. Deverel*1, Christina E. Lucero1, and Sandra Bachand2

Volume 13, Issue 2 | June 2015 * Corresponding author: [email protected] 1 Hydrofocus, Inc., 2827 Spafford Street, Davis, CA 95618 USA 2 Tetratech, Inc., 509 Fourth Street, Suite D, Davis, CA 95616 USA Article doi: http://dx.doi.org/10.15447/sfews.2015v13iss2art4

METHODS 2012 were used. We retrieved water level data from a 57-foot deep USGS well on with Groundwater Levels data from 1983 through 1987 (http://nwis.waterdata. To assess groundwater levels, we used the Delta usgs.gov/nwis/). We also used groundwater level data Wetlands Project groundwater level data col- collected on by HydroFocus personnel lected from 1989 –1995 for wells located on or near from 2006 to 2008. Surveyed measuring point eleva- the levees throughout the Delta (Harding Lawson tions were reported for all these wells, which we used Associates 1991; Hultgren –Tillis 1995). We used to calculate the groundwater elevations relative to these data and groundwater-level measuring point NAVD-88. elevations reported in the Delta Wetland Project documentation (relative to the NGVD-29 datum) to Borehole Lithological Data and Thickness of calculate groundwater elevations. We also obtained Organic Soils and Mud Deposits groundwater level data measured by transducers every 15 minutes during 2004 and 2005 as part of We obtained well and bore-hole logs from the Delta the Upper flood monitoring (Hultgren – Wetlands Project (Harding Lawson Associates 1991; Tillis 2005). We converted all groundwater-level mea- Hultgren-Tillis 1995), the 2004 Jones Tract Flood suring point elevations to NAVD-88 using VERTCON Report (Hultgren-Tillis 2005) and from CDWR (2012 (http://www.ngs.noaa.gov/TOOLS/Vertcon/vertcon. data transfer set to Christina Lucero from Joel Dudas, html) and calculated the groundwater elevations by unreferenced, see “Notes”). These data and data pre- subtracting the depth to water from the measuring- sented in Atwater (1982) were used to define the bot- point elevations. tom elevation of the organic and mud deposits. Using logs available from CDWR, Atwater (1982) posted We also used 2011 and 2012 data for wells from 1,081 useable values for the bottom elevation of the the Dutch Slough groundwater monitoring project organic soils and 562 useable values for the bottom (HydroFocus, Inc. 2012) where water-level data was elevation of the tidal mud deposits on 24-min U.S. recorded every 15 minutes using transducers. Also, Geological Survey (USGS) quadrangle maps. We also manual groundwater level measure- extracted the organic-soil- and mud-bottom eleva- ments collected by HydroFocus, Inc. from 2001 to tions from well logs obtained from CDWR and pub- SAN FRANCISCO ESTUARY & WATERSHED SCIENCE lished in the Delta Wetland Project reports from other of interpolation from measured values of some vari- projects throughout the Delta. able z measured at n locations relies on the deter- mination of the spatial covariance or semivariogram Information sources included: the Alternative of the variable at points x . The semivariogram (γ) is Delta Facilities Special Studies (1976), West Delta i defined as: Temporary Barriers (1977), Hotchkiss Tract Sewage Collection System (1977), Evaluation of Levees variance z ()xi z ()x j at Aqueduct Crossing (1981), γ ()h Supplementary Engineering Studies (1981), McDonald 2 (B-1) Island Piezometer Installation Report (1984), Brannan where; Levee Project (1987), Sherman Island Pipeline 131 Levee Stability Study (1987), Delta Wetlands Project h is the lag or average distance between data (1988), Hotchkiss Tract Treatment Plant Ponds (1988), points, and Hotchkiss Tract PG&E Pipeline Crossing (1990), North Fork Setback Levees (1992), z is the elevation of the organic soil or mud Levee Improvements 2000-2001 (2001), bottom. Jersey Island Triple Decker Project (2003), Bethel We therefore calculated the semivariogram to esti- Island Liquidation Investigation Delta Coves (2003), mate the spatial covariance in the area shown in Jersey Island Geotechnical Data (2004), Groundwater Figure 9 (See page 17 in the paper, http://escholar- Monitoring Jones Tract Flood (2005), Webb Tract ship.org/uc/item/5nv2698k). We then interpolated Geotechnical Investigation Stations 317 & 435 (2007), with kriging which uses a linear combination of Levee Rehab Station 55 to 250 (2008), weighting factors and measured values of that mini- Sherman Island Landslide Setback Habitat Project mizes the estimation variance. (2008), and Horseshoe Bend (2011). We calculated and plotted directional semivariograms Using the Atwater definitions for organic soil and to determine anisotropy. The west to east directional mud bottoms, we extracted 134 organic-soil bottom semivariogram showed the most drift, especially at elevation points and 86 mud bottom elevation points greater distances. In contrast, the north to south from these sources, for dates ranging from the 1970s direction showed the least drift. The greater trend or to 2011. The land surface elevation datum was either drift in the east–west direction reflected increasing listed on the log or assumed to be NGVD-29. We mud and organic soil thickness from east to west, incorporated the locations and elevations of all data especially at the western edge of the Delta. points into a GIS database, resulting in 1,215 organ- ic-soil bottom elevation points and 648 mud-bottom We attempted to model the semivariograms that elevation points. Finally, we converted all points to best represented data for a large geographic area for the vertical datum NAVD-88 using VERTCON. organic-soil-bottom and mud-bottom elevations. The directional spherical and exponential semivariograms To characterize the spatial distribution of the organ- normal to the maximum drift (north–south direction) ic-soil-bottom and mud-bottom elevations and showed the lowest sill variance and were used for thickness, as related to geomorphic processes and kriging for the organic-soil-bottom and mud-bottom the WNMF areas, we used the theory of regionalized elevations, respectively. The semivariogram models variables or geostatistics and Geostatistical Analyst were iteratively verified and refined to minimize the within ArcGIS to create mud bottom and organic-soil estimation variance for both variables. bottom elevation grids. The theory of regionalized variables as described by Matheron (1963), Journel After creating a grid of estimated organic-soil-bottom and Huijbregts (1978), David (1977) and others relies and mud-bottom elevations by kriging, we created a on the description of data collected in geographic mud thickness map by subtracting the mud-bottom areas as randomly distributed. “Kriging," the process elevation grid from the organic-soil-bottom elevation

2 JUNE 2015 elevation grid from the organic-soil-bottom elevation REFERENCES grid in GIS. Similarly, we created an organic-soil- bottom thickness map by subtracting the organic- Atwater BF. 1982. Geologic maps of the Sacramento- soil-bottom elevation grid from the LiDAR (Light San Joaquin Delta, . U.S. Geological Survey Detection and Ranging) land–surface elevation grid Map MF-1401. Reston (VA): U.S. Geological Survey. (CDWR 2007), which is reported in NAVD-88. David M. 1977. Geostatistical ore reserve. New York (NY): Elsevier Scientific. RESULTS Harding Lawson Associates. 1991. A Report Prepared Groundwater Elevations for Delta Wetlands: Groundwater Data Transmittal No. 2 Delta Wetlands Monitoring Program We examined groundwater elevations using available Sacramento- Delta. HLA Job No. data for the aquifer underlying the organic deposits. 18749,007.03. Examination of hydrographs (Figure B1) for wells installed throughout the Delta generally demonstrated [Hultgren-Tillis] Hultgren-Tillis Geotechnical temporally stable groundwater elevations during the Engineers. 1995. Groundwater data transmittal no. last 20 years. There are three exceptions. First, there 4 Delta Wetlands Project Sacramento-San Joaquin was a slight downward trend in groundwater eleva- River Delta. Project No. 101.03. Concord (CA): tions for well WO-26 on Woodward Island. However, Hultgren-Tillis Geotechnical Engineers. data collected during 2003 and 2004 indicate stable [Hultgren-Tillis] Hultgren-Tillis Geotechnical groundwater elevations from 1995 to 2004. Second, Engineers. 2005. Groundwater monitoring Jones Tract data collected in wells MC-13 and MC-14 on flood Sacramento-San Joaquin Delta, California. McDonald Island indicate precipitous declines and Prepared for the California Department of Water recovery during 1990 and 1991 when groundwater Resources. Project no. 101.22. Concord (CA): levels returned to close to previous levels. Third, there Hultgren-Tillis Geotechnical Engineers. was an apparent downward trend on Medford Island. Recent data for wells on Upper Jones and Palm HydroFocus, Inc. 2012. Dutch Slough restoration area Tract demonstrate a lack of significant water-level first and second quarters 2012 groundwater semi- change during the longer term from 1989 to 2004. annual groundwater monitoring report. Prepared The hydrograph for Upper Jones Tract shows the for the California Department of Water Resources, effect of the levee breach in 2004 and then a return October 5, 2012.Journel AG, Huijbregts CHJ. 1978. to groundwater levels similar to those measured in Mining geostatistics. New York (NY): Academic Press. the 1990s. Also, the Twitchell Island data shows no Journel AG, Huijbregts CHJ. 1978. Mining multi-year trend from 2001 to 2013. geostatistics. New York (NY): Academic Press. Matheron G. 1963. Principles of geostatistics. Econ Geol 58:1246-1266. doi: http://dx.doi.org/10.2113/ gsecongeo.58.8.1246

NOTES Dudas J. 2012. Soil test data folder. Data transfer to Christina Lucerro containing borehole logs and shapefiles of locations in the Sacramento-San Joaquin Delta. Located on server at Hydrofocus, Inc., 2827 Spafford Street, Davis, CA 95618.

3 SAN FRANCISCO ESTUARY & WATERSHED SCIENCE JUNE 2015

Appendix B - A

Twitchell Island Webb Tract Brannan‐ Staten Island ‐15 ‐4 ‐2 ‐7 ‐10 29) 29) 29) 29) 29) ‐11

‐15.5 ‐6 ‐2.5 ‐8 ‐12 NGVD NGVD NGVD NGVD NGVD

‐3 ‐16 ‐8 ‐9 ‐13 (ft; (ft; (ft; (ft; (ft;

‐3.5 ‐14 ‐16.5 ‐10 ‐10 WE‐3 ‐4 BO‐16 ‐15 ST‐7 Elevation Elevation Elevation Elevation Elevation

OW‐25C BR‐22 ‐17 ‐12 WE‐4 ‐11 BO‐28 ‐16 ST‐8 ‐4.5 ‐17 ‐17.5 ‐14 ‐5 ‐12 ‐18 Groundwater Groundwater Groundwater Groundwater Groundwater

‐18 ‐16 ‐5.5 ‐13 ‐19

Tyler Island

Mandeville Island Brannan-Andrus ‐3 ‐6 ‐2.0 ‐3.5 29) 29)

‐2.5 29) Staten Island ‐8 ‐4 ST-8 ‐3.0 NGVD NGVD

NGVD ‐4.5 (ft; (ft;

‐10

(ft; ‐3.5 ‐5 BO-28 ST-7 ‐5.5 ‐12 ‐4.0 MA‐23 TE‐9 Elevation Elevation

‐6 Elevation EM‐31 MA‐24 BO-15 Terminous Tract TE‐10 ‐4.5 ‐14 ‐6.5 MA‐25 BO-16 TE-10 ‐5.0 Twitchell Island ‐7 ‐16 Bouldin Island ‐7.5 ‐5.5 BR-22 Groundwater Groundwater Groundwater OW-25C ‐8 ‐18 ‐6.0 VN-33 EM-31 VN-34 TE-9

Bradford Island Webb Tract Venice Island Venice Island Medford Island Bethel Island WE-3 Empire Tract 2 ‐4 2 WE-4 ‐4.5 MA-24 0 29)

29) Sherman Island MA-25 VN-32 29) 1 ‐2 ‐5 NGVD NGVD

0 ‐4 ‐5.5 NGVD BE-11

(ft;

(ft; ‐6

(ft; ‐6 ‐1 ‐6.5 BE-19 ‐8 VN‐32 ‐2 Medford Island

BE‐11 Elevation Elevation

‐10 VN‐33 ‐7 002N004E02L001M

Elevation Jersey Island BE‐12 ‐3 Bethel Island ‐12 VN‐34 ‐7.5 BE‐19 ‐4 HO-1 ‐14 ‐8 ‐8.5 ‐16 Groundwater ‐5 HK-18 Groundwater Groundwater BE-12 BA-5 MA-23 ‐18 ‐9 ‐6 HO-2 McDonald Island Hotchkiss Tract Holland Tract HK-17 Hotchkiss Tract Holland Tract McDonald Island Upper Jones Tract MC-13 2 ‐5 VE-20 MC-14 ‐8 0 ‐5.5 PA-29 29) 29) 29) 29)

1 ‐9 ‐2 ‐6 Veale Tract 0 PA-30 ‐10 NGVD NGVD NGVD NGVD ‐6.5 BA-35 ‐4 (ft; (ft; (ft; (ft;

‐11 ‐1 ‐7 ‐2 ‐7.5 Lower Jones Tract ‐12 ‐6 HK‐17 HO‐1 MC‐13 Elevation Elevation Elevation Elevation

‐3 ‐8 BA-6 ‐13 UJ‐21 HK‐18 HO‐2 WO-27 MC‐14 ‐8 ‐8.5 ‐4 ‐14 ‐9 UJ-21 ‐10 ‐5 ‐15

‐9.5 Groundwater Groundwater Groundwater Woodward Island Groundwater ‐6 ‐10 Upper Jones Tract ‐16 ‐12

WO-26

Veale Tract Palm Tract Woodward Island Bacon Island ‐7 0 ‐4 ‐8 29) 29) 29)

29) ‐7.5 ‐2 ‐6 ‐10 ‐8 ‐4 NGVD NGVD NGVD NGVD ‐8 ‐12 (ft; (ft; (ft;

(ft;

‐8.5 ‐6 ‐10 ‐9 ‐8 ‐14 BA‐5

PA‐29 Elevation Elevation Elevation WO‐26

‐12 Elevation ‐9.5 VE‐20 ‐10 PA‐30 WO‐27 ‐16 BA‐6 ‐10 ‐12 ‐14 ‐18 ‐10.5 ‐14 ‐16 Groundwater Groundwater Groundwater Groundwater ‐11 ‐16 ‐18 ‐20 0 2.5 5 10

Kilometers I

Figure B1 Map with groundwater hydrographs in the aquifer underlying organic deposits