Application of HydroGeoSphere in Impact Analysis of Land Subsidence due to Increased Groundwater Withdrawal along the Delta-Mendota Canal

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1 Application of HydroGeoSphere in Impact Analysis of Land Subsidence due to Increased Groundwater Withdrawal along the Delta-Mendota Canal Kirk Nelson Nigel Quinn Lisa Rainger George Matanga 03/01/11 1 US Bureau of Reclamation Mid-Pacific Regional Office, Sacramento

2 Motivation Land subsidence impacts include Loss of GW storage 1 Damage to structures (e.g., aqueducts, roads, bridges, buildings, well casings) 1 Need to realign canals to regain constant gradient 2 Need to relevel furrowed fields 2 Increased potential for flooding and seawater encroachment USGS Professional Paper USGS Open-File Report

3 Historical Subsidence in Los Banos- Kettleman City Area (near DMC) From 1920 s to 1990, ~1/3 of GW pumped from storage in this area came from compaction of fine-grained sediments 1 Largest area of subsidence (~1500 mi 2 ) in the San Joaquin Valley (SJV) 1 Head declines of up to 500 ft in confined aquifer yielded up to 28 ft of subsidence 1 30% of sediments in upper 2000 ft of aquifer are fine-grained (highest in SJV) USGS Professional Paper 437-H 2. USGS Professional Paper 1766

4 Water Use/Subsidence Link in Los Banos-Kettleman City Area Importation of surface water in 70 s and 80 s greatly slowed or stopped land subsidence 1 In droughts ( ; ), GW pumpage, compaction increase potential subsidence 1 Thus, need exists to estimate the volume of GW, as well as its distribution in space and time, that can be safely pumped in drought periods. Spatial refinement of model predictions is key to protecting structures like the DMC USGS Professional Paper 1766

5 HydroGeoSphere (HGS) Land Subsidence Module Terzaghi s 1D instantaneous compaction principle 1 incorporated into HGS 2 Model applied to the Toluca Valley in Mexico 2 Calibrated model successfully reproduces observed hydraulic heads and compaction Terzaghi K. Earthworks mechanics based on soil physics. Erdbaumechanik auf 1037 bodenphysikalisher Grundlage. Vienna: Franz Deuticke; Calderhead et al. Simulating pumping-induced regional land subsidence with the use of InSAR and field data in the Toluca Valley, Mexico. Adv. Water Res. 34:

6 Application to DMC Project Status Initial parameterization completed largely via data transfer from CVHM 1 HGS code modified to accommodate spatial variability of compaction properties (e.g., fraction of compressible interbeds; preconsolidation heads) Parameter adjustments underway to reduce model run times for surface flow Calibration to historical head and compaction underway for subsurface flow USGS Professional Paper 1766

7 Model Grid Variable resolution allows more detailed simulation in areas of interest Spatially refined along major rivers and canals

8 CVHM HGS Data Transfer Utility program created to read CVHM input arrays, extract, manipulate, and format data for HGS input files. Interpolation algorithms Search for CVHM cell containing HGS element centroid for HGS elemental data Bilinear interpolation of data from 4 CVHM cells for HGS nodal data

9 Model Input Data 1 Parameter Horizontal and Vertical hydraulic conductivity (K xx and K zz ) Porosity (θ) Source CVHM input arrays of percentage of coarse-grained material (P c ) coupled with statistical relationships correlating P c with K xx and K zz (USGS PP 1766). CVHM input arrays of percentage of coarse-grained material (P c ) coupled with statistical relationships correlating P c with θ (USGS PP 1766). Specific storage Table C8 of USGS PP 1766 Elastic skeletal specific storage Table C8 of USGS PP 1766 Inelastic skeletal specific storage Table C8 of USGS PP

10 Model Input Data 2 Parameter Fraction of compressible interbeds Surface flow parameters (x and y friction, rill storage height, obstruction storage height, coupling length) Preconsolidation head Initial head Initial water depth in streams Source CVHM input arrays of percentage of fine-grained material (P c ) and model layer thicknesses. CVHM land use input arrays coupled with published values (e.g., from hydrology textbooks or scientific papers) based on correlations btw land use and flow parameters. CVHM input arrays (Preconsolidation heads were found by USGS to occur in 1961). CVHM input arrays To be determined by HGS steadystate model run

11 Model Input Data 3 Parameter Groundwater pumping Surface water deliveries Precipitation Stream inflows Evapotranspiration Source USGS and CCID datasets and maps CVHM farm package output arrays CVHM input arrays (original source: PRISM) GIS shapefile of CVHM data provided by Claudia Faunt (USGS) CVHM input arrays

12 Model Input Data Hydraulic Conductivity

13 Model Input Data Fraction of Compressible Interbeds

14 Model Input Data Groundwater Wells SW deliveries specified base on CVHM farm package water delivery areas GW pumping specified based on individual well locations (obtained from CCID and USGS databases)

15 Summary Initial model parameterization complete Initial calibration to historical head and compaction data underway for subsurface (variably saturated) flow Incorporation of surface flow to proceed in parallel Calibrated model (subsurface) expected ready for analysis of 2012 pumping plans

16 Acknowledgments Liz Partridge (USBR, Tracy) René Therrien (Univeristé Laval) Tom Heinzer, Diane Williams (USBR GIS) Clarence Leung (USBR intern, now BLM)

Appendix D. Sediment Texture and Other Soil Data

5 6 7 8 Appendix D. Sediment Texture and Other Soil Data This appendix describes the sediment texture of the aquifer system in the Restoration Area. The contents of this appendix describe the: Importance