Data sources

Provenance & refresh cadence

Data sources

Every dataset Field Risk Atlas uses, with publisher, vintage, license, and a link to the canonical source page. All public; no proprietary or restricted data.

Regulatory and basin layers

Groundwater basin boundaries (Bulletin 118)

• Publisher: California Department of Water Resources (DWR)
• Source: B118 California Groundwater Basins (i08) · DWR Bulletin 118
• Vintage: 2025 release
• License: Public California state government data
• In the model: 515 basins and subbasins. Each parcel is assigned to the basin it falls in, which carries its priority and overdraft signals.

SGMA basin prioritization

• Publisher: DWR
• Source: SGMA Basin Prioritization
• Vintage: 2019 final prioritization
• License: Public CNRA data
• In the model: Each basin's priority (Very Low / Low / Medium / High) feeds the basin-priority component of the score. Statewide distribution: 410 Very Low, 48 Medium, 46 High, 11 Low.

Critically overdrafted basins

• Publisher: DWR
• Source: Critically Overdrafted Basins (i08 COD) · DWR Critically Overdrafted Basins page
• Vintage: Updated 2022-12
• License: Public CNRA data
• In the model: 21 basins flagged as critically overdrafted (pumped faster than they recharge). Binary signal in the composite.

Groundwater Sustainability Plan (GSP) areas

• Publisher: DWR / SGMA Portal
• Source: GSP Areas (i03) · SGMA Portal
• Vintage: DWR-maintained, monthly refresh
• License: Public CNRA data
• In the model: 121 GSP polygons across 92 unique basins. Joined at runtime to the GSP status crosswalk below, which captures SWRCB and DWR enforcement statuses the base layer doesn't reflect.

GSP status crosswalk (verified 2026-05-10)

Field Risk Atlas maintains a small crosswalk of current SWRCB / DWR enforcement statuses for the seven v1 subbasins where status diverges from the base GSP layer. Each entry is sourced from the State Water Resources Control Board:

Refresh cadence: monthly, or sooner when SWRCB / DWR action is announced.

Surface water

Water districts

• Publisher: DWR
• Source: Water Districts (i03)
• Vintage: DWR-maintained
• License: Public CNRA data
• In the model: 4,021 polygons covering Central Valley Project (CVP) contractors, State Water Project (SWP) contractors, agricultural water districts, urban districts, and wholesalers. Each parcel inherits the district(s) it overlaps.

ASFMRA water-tier ranking

• Publisher: American Society of Farm Managers and Rural Appraisers (ASFMRA)
• Source: ASFMRA Trends Report (annual; methodology reference)
• In the model: District-level reliability ranking (Tier 1 through Tier 4, plus "white-area" for parcels with no surface-water district). Tier 1 = senior CVP/SWP contracts with most-reliable deliveries; white-area = groundwater-only.

Crop coverage

Land IQ Statewide Crop Mapping

• Publisher: DWR
• Source: Statewide Crop Mapping · DWR Land Use Surveys
• Vintage: 2023 final release (2024 still provisional)
• License: Public DWR data
• In the model: Per-parcel dominant crop assignment. Land IQ covers ~67% of v1 ag parcels (it maps actively-cultivated commodity ag fields, not rangeland or fallowed acreage).

USDA Cropland Data Layer (CDL)

• Publisher: US Department of Agriculture (USDA) National Agricultural Statistics Service (NASS)
• Source: USDA NASS CDL · CropScape interactive viewer
• Vintage: 2024 release
• License: Public USDA data
• In the model: Fallback for the ~33% of parcels Land IQ doesn't cover. Most CDL-classified parcels resolve to grassland or pasture.

Groundwater (wells)

DWR well completion reports

• Publisher: DWR
• Source: Well Completion Reports (i07)
• Vintage: Continuously updated
• License: Public DWR data
• In the model: 1.1 million statewide records → 196,000 filtered to v1 counties → aggregated to ~12,000 Public Land Survey System (PLSS) sections. Median well depth per section informs the local-well-depth signal. DWR's metadata documents known missing and duplicate records; aggregating to section median is robust to outliers.

BLM PLSS section polygons

• Publisher: US Bureau of Land Management (BLM)
• Source: BLM Cadastral National Spatial Data Infrastructure (CadNSDI)
• Vintage: Continuously maintained
• License: Public BLM data
• In the model: PLSS section polygons (Township-Range-Section grid) are the spatial join key between well records and parcels. Mexican Land Grant rancho polygons in Sonoma don't carry T/R/S and are excluded — affected parcels won't have well-depth statistics.

Drought

US Drought Monitor (USDM)

• Publisher: National Drought Mitigation Center, USDA, and NOAA
• Source: US Drought Monitor · USDM Data Services API
• Vintage: Weekly publication; current snapshot 2026-05-05
• License: Public
• In the model: Per-county weekly severity (None / D0 / D1 / D2 / D3 / D4). The score uses a 52-week count of weeks where at least 50% of the county area was at D2 (severe drought) or worse. All 9 v1 counties currently sit at 0 weeks — California is in a wet period after the 2020–22 drought.

Parcels (per-county GIS)

Each county publishes parcel boundaries through its own assessor or GIS portal. Field Risk Atlas fetches each county's layer directly at ingest time:

Raw county parcel data is fetched at runtime and not committed to the repo (Kern's attribution disclaimer requires this posture; the others are also fine to fetch at runtime).

Reference tables (manually maintained)

A handful of small CSVs encode mappings the upstream sources don't provide:

• GSP status crosswalk — basin → current enforcement status (the table above)
• Water-tier crosswalk — water district → ASFMRA Tier 1–4 (or non-ag n/a)
• Crop class crosswalk — Land IQ crop codes → score-model crop class (almonds, vines, row crops, etc.)
• CDL class lookup — USDA CDL integer codes → crop name → score-model crop class

Refresh cadence

What is not in this project

• No proprietary, restricted, or organization-internal data, ever.
• No commercial parcel aggregators — license restrictions are incompatible with open-source release.
• No appraisal-grade data.