1. Western placer county groundwater management plan model
Model Development and Site Conceptual Model

2. Model Domain Bear River Sierra Nevada Feather River Sacramento River
Mokelumne River

3. Model Layering and Outcrops

4. Riverbank Formation Model Layer 1 General Features:
View Facing North
View Facing South
General Features:
Middle to Late Pleistocene deposits (formerly the Victor Formation)
Consists of sands, silts, and clays from floodplain and alluvial deposits
Superjacent ancestral stream channels cut across this formation creating
lateral channels of gravels and unconsolidated sediments
Hardpan deposits are prevalent in this formation that inhibit vertical
infiltration of recharge from applied water and precipitation

5. Turlock Lake Laguna Formation
Model Layers 2 and 3
View Facing North
View Facing South
General Features:
Early Pleistocene to late Pliocene deposits (formerly the Fair Oaks Formation)
Predominantly consists of sands, silts, and clays
Superjacent ancestral stream channels cut across this formation, creating
lateral channels of gravels and unconsolidated sediments
Characteristic feature: white to grey tuff and tuffaceous silts “white clay”

6. Mehrten Formation Model Layers 4 and 5 General Features:
View Facing North
View Facing South
General Features:
Pliocene deposits formed during an erosional sequence following chain of
volcanic eruptions
Composed of two dominant units:
Black andesitic sands “salt and pepper sand” and blue and brown clays
Hard gray and black tuff-breccias “lava”
Localized confining units , degree of confinement increases to the west
Significant water bearing unit

7. Valley Springs Formation
Model Layer 6
View Facing North
View Facing South
General Features:
Middle Miocene deposits formed during sequence of volcanic eruptions
Consists of rhyolite ash, quartz sand , and ashy clay
Characteristic features: olive green – greenish gray tone of clays, silts
Typically low permeable deposits
Near Lincoln area, productive zone with upward groundwater gradients

8. Ione Formation Model Layer 7 General Features:
View Facing North
View Facing South
General Features:
Consists primarily of sandstone and clays deposited during the Eocene epoch,
a time when the ancient sea became fresh to brackish.
The Ione Formation outcrops to the east, where freshwater remains at
shallow depths
Generally low in permeability, although secondary fracturing near the
outcrops is believed to provide a source of water to unit

9. GeoSections

10. Hydrogeology

11. Ancestral Streams

12. Rivers Rivers Begin with a simplified approach
River stage data used as model input
Flow data used for calibration (net flux)
Locations along the Sacramento River have been
adjusted for tidal influences
Flow at river confluences estimated using upstream
gages
Assumption that a portion of the flow discharges
from the Sacramento River to the Deep Water
Channel and Steamboat Slough
Streams package is available if warranted

13. Recharge 1 2 3 4 5 6 7 Estimating Recharge in the WPCGMP Model:
Ungaged Watersheds
Estimating Recharge in the WPCGMP Model:
Gridded Surface Subsurface Hydrologic Analysis
Simulation Modeling (GSSHA):
2D Grid Based Hydrologic Model
Overland Flow, Stream Flow, Infiltration
Soil Data (Soil Data Mart)
Land Use Data (Farm Data)
Precipitation Gages
Meteorological Data
Water Year Classifications
Custom codes for output and data processing
GSSHA Simulations run for representative water
years to develop recharge factors for specific water
year classifications
19 Soil Type Land Use Combinations (STLUs)
Recharge factors for each of the 19 STLUs were
developed, accounting for change in land use and
water year type, and used to develop subsurface
infiltration from precipitation and applied irrigation
water and inflow from ungaged watersheds

14. ESRI Model Builder Applications
Recharge Work Flow
ESRI Model Builder Applications
Estimating Recharge in the WPCGMP Model :
Parameter-elevation Regressions on Independent Slope Model (PRISM)
monthly gridded precipitation data published by the PRISM Climate
Group (monthly)
Correlation with local rainfall gages
Applied water from irrigation (monthly) – output from Water Demand
Model
Recharge factors from GSSHA simulation modeling

15. GMS Zone Codes GMS Zone Codes Assignment of Demand Factors
Budget Summary
Supply Data
Surface Water
Supply
Additional
Groundwater
Pumping

16. Change from Non-urban to Urban
Land Use Patterns
Master Land Use File
Farm Data
Change from Non-urban to Urban

17. Supply and Delivery Data
Groundwater Supply Data
Western Placer Groundwater Storage Study
SGA Data Management System
City of Lincoln Summary Data
Surface Water Entitlements
PCWA
City of Roseville
City of Lincoln
Natomas Central Mutual Water Co.
Pleasant-Grove Verona Mutual Water Co.
South-Sutter Water District
Surface Water Delivery Data
City of Roseville Supply Data
City of Lincoln Supply Data
SGA Data Management System
City of Lincoln Groundwater Management Plan
Wrime Technical Report:
Model Refinement North Area
City of Lincoln Supply and Private Contracts
15% of private supply comes from GW
Nevada Irrigation District – all SW
Surface Water Delivery Summary for:
City of Sacramento
Rio Linda/Elverta Community WD
Natomas Central Mutual Water Co.
City of Folsom
Aerojet Area
Florin-Vineyard Gap Community Plan
Summary of Sacramento County General Plan
Master Water Study for the Florin-Vineyard
Community Plan
Zone 41 Urban Water Management Plan
California American Water Supply Assessment

18. Water Unit Demand Factors
Agricultural Demand Factors (DWR)
Model Output for Representative Water Years
Urban Demand Factors
Normalization Factor based on Water Year Index
Monthly Conversion Factors
Water Year Index
2002 ITRC Crop Evapotranspiration
Rates for Eto Zone 14
ITRC Report , funded by
CALFED and Agricultural Research
Initiative of California State Univ.

19. Water Demand Model Workflow Assign WUD factors (monthly)
Determine Change in Land Use (every two years)
Assign WUD factors (monthly)
Regional Urban Demand Factors for “New Growth” developed for each WP
Calculate Acreage
Calculate Total Demand (monthly)
Tabulate Total Surface Water Supply (monthly)
Tabulate Total Groundwater Pumping (monthly)
Tabulate Surface Water Entitlements (annual)
Assign Deficit in Budget to Existing Wells for each GMS Zone Code (monthly)

20. Comparison with Existing Models
WPCGMP
Aerojet Model
SACIGSM v3
Modeling Platform: Public Code (MODFLOW) Public Code (MODFLOW) Proprietary Code (IGSM w updates)
Model Processes: Finite Difference Finite Difference Finite Element
Pre-Post Processors: GMS & Arc Hydro Groundwater GWVISTAS v IGSM
Domain: Regional (3 subbasins) Local Scale (Aerojet) Regional (multiple models)
Projection: NAD 83, State Plane, CA 2 (ft) NAD27, State Plane, CA2 (ft) UTM Zone 10, NAD27 (m)
Model Layers: 7 Layers Layers 5 Layers (2 fresh-water aq.)
Layering Approach: Wedge (outcrops) Flat – Stacked Flat – Stacked
Base of Model: Modified Continental Deposits Bedrock/Cont. Deposits Continental Deposits (DWR)
Input Assignments: Materials Approach Grid Assignment Interpolated Nodes
Conceptual Model: Stored in Model External to Model External to Model
Grid Refinement: Automated, map over inputs Manual w/o CM Manual
North Boundary: Bear River (gage data) General Heads Links to NARIGSM models (post 1995 values held constant)
South Boundary: Mokelumne River (gage data) No flow Links to STNIGSM models (post 1993 values held constant)
West Boundary: Sacramento & Feather Rivers General Heads Links to CVIIGSM models (post 1995 values held constant)
East Boundary: Ungaged Watersheds No flow Ungaged Watersheds
Primary Inflow: Streamflow Recharge Deep Percolation
Primary Outflow: Pumping Pumping Pumping
Calibration Period: (Phase 1)