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

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

Model Layering and Outcrops

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

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”

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

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

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

GeoSections

Hydrogeology

Ancestral Streams

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

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

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

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

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

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

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 02-001, funded by CALFED and Agricultural Research Initiative of California State Univ.

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)

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 4.21 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 6 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: 1998-2008 (Phase 1) 1956-2006 1969-2004