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SACFEM Model Development Update

SACFEM Model Development Update

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SACFEM Model Development Update

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  1. SACFEM Model Development Update Sacramento Valley March 19, 2009

  2. Discussion Topics • Status of Task Order CH2M-DPLA-001 • Status of Task Order CH2M-DPLA-008 • Review of historical GW/SW data • Model grid revision • Stream flow triggers • Develop surface water budget terms for new model grid • Steady state calibration • Transient calibration

  3. Task Order CH2M-DPLA-001 • Task 1 – Micro-FEM Workshop and Support • Task 1.1 – Micro-FEM Model Workshop • Task 1.2 – Micro-FEM Model Support • Task 2 – Sacramento Valley Water Management Agreement Policy Support • Task 3 – Project Management and Administration

  4. Task Order 001 Status • Task 1 has not yet been performed • DWR requested that the training workshop be delayed until the transient version of SACFEM becomes available • Task 2 is complete • Approximately $17,000 remains on this task order to conduct a training workshop and provide additional on-call support • Additional funds will be necessary to achieve “user level” training of DWR staff

  5. Task Order CH2M-DPLA-008 • Task 1 – Model Enhancement and Refinement • Model grid revision • Develop surface water budget terms for revised grid • Develop initial conditions for 2009 evaluation period • Evaluate stream recharge timing

  6. Task Order CH2M-DPLA-008 • Task 2 – Transient Calibration • Task 3 – Technical Memorandum • Task 4 – Application of SACFEM model

  7. Task Order 008 Status • Model grid revision – complete • Develop surface water budget terms for new model grid – complete • Develop initial conditions for 2009 Evaluation Period – will select based on final results of transient calibration runs • Evaluation of stream recharge timing – complete

  8. Task Order 008 Status • Transient calibration – • Due to delays in developing a final grid applicable to both Phase 8 and water transfers, a formal transient calibration on the original SACFEM grid has been completed • A steady-state calibration on the new grid is complete • The final transient calibration runs using the new grid are in progress

  9. Task Order 008 Status • Technical Memorandum – a technical memorandum documenting the transient version of SACFEM will be prepared following completion of calibration • Application of SACFEM – Two proposed transfer/conjunctive use projects will be evaluated using SACFEM following completion of calibration

  10. Review of Available Data • Ground water elevation • Stream flows • Precipitation

  11. New Grid Development • The original objective of this task was to develop a new finite-element grid that is refined in areas where water transfers are anticipated • The overall gridding approach was discussed with DWR modeling staff, and it was decided that we should try to develop one grid that would suffice for both the SVWMP and water transfer analysis

  12. New Grid Development • Due to prior commitments, SVWMP projects need to be evaluated at a grid resolution of ~100 meters • Potential water transfer participants were identified by DWR and also incorporated into the grid at a resolution of ~250 meters • The Sacramento and Feather River corridors were also represented at higher resolution • The final grid contains approximately 120,000 surface nodes

  13. Stream Flow Triggers • Better estimate of ephemeral stream recharge • Identification of streams used for conveyance of irrigation supplies • Identification of flood flows

  14. Stream Flow Triggers • AMERICAN_RIV • ANTELOPE_CR • BEAR_RIV • BIG_CHICO_CR • BUTTE_CR • CACHE_CR • COLUSA_BD • CONSUMNES_RIV • DEER_CR_BUTTECO • DEER_CR_CONSUMNES • DRY_CR_PUTAH • ELDER_CR • FEATHER_RIV • FRENCH_CR • FUNKS_CR • GCID_CANAL • LITTLE_CHICO_CR • MILL_CR_BUTTECO • MOKELUMNE_RIV • NF_WALKER_CR • PAYNES_CR • PUTAH_CR • Sac_River_BendtoRB • Sac_River_GCID_to_Wilkins • Sac_River_RB_To_GCID • Sac_River_Wilkins_End • SALT_RIV • SAN_JOAQUIN_RIV • SAND_CR • SEVENMILE_CR • SF_WILLOW_CR • STONE_CORRAL_CR • STONEY_CR • TC_CANAL • THOMES_CR • WALKER_CR • WILLOW_CR • WILSON_CR • YUBA_RIV Elder Creek

  15. Example of Streams UsedFor Water DistributionGCID

  16. Sacramento Basin Floodplain • Flood plane not included in GW model Frequency of Freemont Weir Flow

  17. Water Budget Development • Water budget terms include: • Deep percolation • Applied water • Precipitation • Groundwater pumping • Monthly time-series for each gw model element

  18. Crop Unit Factors GW Model Grid Water Budget Development cont. Land Use Data

  19. Crop Unit Factor Tables • Developed with IWFM Demand Calculator • 19 crop types + native vegetation • Water budget terms calculated for one acre • Sacramento Valley broken into approximately 72 demand units based on location, water source, contracts, etc.

  20. GIS Data Processing Land Use Data Water District Boundaries GW Model Grid

  21. Groundwater Pumping Calculation • IDC calculates total applied water demand • Separate GIS land use/demand unit file that includes water source attribute • Demand calculated for groundwater areas • Areas with mixed supplies calculated based on estimates of available surface water • Estimated by water rights/contracts • Water year type for non-district areas

  22. Database Analysis NODE 5005 SO CR GR OR AP • Crops • Demand Unit Type • Crop Name • Acreage

  23. Database Calculation Workflow Shapefile • Node cell number (value) • Many sub-crop areas within 1 node cell • Crop Type (value) • Demand Unit (value) • Acreage (value) Crop Tables • Crop Type (table) • Demand Unit (field) • Time step (value) Result Tables • Node number (value) • Time step (field) • Calculate and accumulate Acreage x DU for all crop types for each time step for every node.

  24. Time steps Node numbers For Node Number = 0 @ Timestep 1970.1 Time steps 2nd Crop = RI Area = 1.8739 2nd DU = 8N_PS2 From Crop Table ‘ri.dbf’: Field = “cr_8n_ps2” DU value = 0.51 Subtotal WD = 1.8739 x 0.51 = 0.956 1st Crop = CR Area = 0.5801 1st DU = 8N_PS2 From Crop Table ‘cr.dbf’: Field = “cr_8n_ps2” DU value = 0 Subtotal WD = 0.5801 x 0 = 0 Time steps Total AWD for Node number 0 @ Time step 1970.01 = 0 + 0.956 ~ 1.0 Node numbers Sample Database Process

  25. GW_Pumping Sample Database Process (cont’d) Get Minimum (MIN) DU_Lookup % GW AWD_TOTAL AWD_GW For each node and time step: GW_Pumping = (AWD_TOTAL – MIN) X %GW) + MIN e.g. Node 12502, TS 1970.07: GW_Pumping = (21.3 – min(21.3, 3.9)) x 0.1 + 3.9 = 5.6 e.g. Node 12502, TS 1970.08: GW_Pumping = (81.5 – min(81.5, 14.9)) x 0.1 + 14.9 = 21.6

  26. 1. DP of AW calculated for 2.0 M acres of agricultural lands in model 2. DP of precip calculated for 3.8 M acres total area in model, revised in GW model during calibration 3. GW pumping calculated for 860,000 acres of areas with gw or mixed water source attribute

  27. Annual Sac Valley Ag Pumping

  28. Water Budget Modifications • Water budget developed by MBK did not include urban pumping • Urban pumping was added to the model for communities with populations greater than 5,000 people (2000 census) • Assumed 200 gal/capita/day • Pumping added within city boundaries • Higher estimates used in Chico and Sacramento to match observed groundwater levels

  29. Water Budget Modifications • Mountain front recharge included to represent inflows to the model domain within watersheds of streams not explicitly represented in the model • PRISM rainfall data used to compute average annual rainfall for each polygon • Turner (1991) relationship used to estimate deep percolation quantity from rainfall data

  30. Water Budget Modifications • The deep percolation of precipitation provided by the modified MBK analysis was significantly higher than the estimates provided by the previous analysis and required reduction • Deep percolation of applied water and agricultural pumping quantities were input to the model as provided by MBK

  31. Water Budget Modifications • Deep percolation of precipitation was reduced based on: • Hydrologic soil groups (A-100%, B-80%, C-50% and D-20%) • Further adjustments made by water budget areas to improve agreement between simulated and observed groundwater levels

  32. Calibration • The groundwater model was calibrated to several quantitative and qualitative calibration targets: • Average 2000 groundwater elevations (257 wells used as calibration targets) • Areas of gaining and losing streams (approximate) • Approximate water budget quantities (order of magnitude comparison as no precise estimates available)

  33. Steady-State Calibration

  34. Transient Calibration • The first step in the transient calibration was to develop a target water level data set • The entire DWR CV database of almost 40,000 monitoring wells was screened based on: • Available construction information • Available data records within the 1970 through 2003 calibration period • Geographic distribution throughout the model domain and with depth

  35. Transient Scattergram

  36. Available Tools • Pre and post processors for SACFEM

  37. Pre- and Post-Processors During this effort several Excel based pre- and post- processing packages were developed in VBA code that will greatly simplify future input file creation and model output analysis and interpretation These packages include: A tool that reads well construction information and model interface elevations and reports percent of screen in each layer and assigns wells to the appropriate layer

  38. Pre- and Post-Processors Processing Packages (Continued): A tool that reads summary input files and creates monthly Micro-FEM input files including deep perc, pumping, stream properties, mountain front recharge, and model control parameters A tool that reads head output and a well list and automatically creates drawdown hydrographs for selected layer combinations

  39. Pre- and Post-Processors Processing Packages (Continued): A tool that reads transient head output and computes calibration statistics and creates multiple scattergrams as desired A tool that reads simulated stream fluxes and generates a plot of transient stream flow reduction for every stream in the model

  40. Summary • A revised model grid has been developed to support the SVWMP and water transfers • A GIS-based algorithm has been developed to project surface water budget components onto any model grid • The recharge behavior of west side tributary streams has been further evaluated and tools developed • The SACFEM model has been projected onto the new model grid

  41. Summary • The steady-state calibration of the SACFEM model on the new grid is complete • A transient calibration of SACFEM on the original model grid is complete and final calibration with the new grid is near completion