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Home , Groundwater banking

STATEWIDE LAND SUITABILITY FOR RECHARGE

January 28, 2019

Presented To

Groundwater Resources Association

Mica Heilmann, CPSS, CPESC PRESENTATION OUTLINE

• Introduction to Land IQ • Introduction to Suitability Index • Overview of Data Inputs • Suitability Rating Methods • Groundwater Recharge Suitability Index Results LAND IQ BACKGROUND • Land Resource, Agricultural and Spatial Scientists

• Integrating land-based science with spatial analytics • Statewide Crop Mapping • Crop Age Determination • Land Classification and Consumptive Use Estimates • Spatial Evapotranspiration • Agricultural Yield • Central Valley Wide Groundwater Recharge Potential STATEWIDE GROUNDWATER RECHARGE SUITABILITY INDEX • #1 – Can you infiltrate & percolate water through the root zone? • #2 – Once it is through the root zone, can it be stored and/or will it be restricted for recharge? • Combines both surface and subsurface conditions in a sequential and logical approach STATEWIDE GROUNDWATER RECHARGE SUITABILITY Data Inputs: • Agricultural Groundwater Banking Index (SAGBI) • USGS Groundwater Levels • Central Valley Hydrologic Model (CVHM) • Irrigation District Coverage DATA INPUT: SAGBI • Soil infiltration rate/drainage capacity • Topography • Soil • Soil surface condition (propensity to erode or form crust)

• Identified 3.6 million acres with good potential for groundwater banking • Focused on surface (top 5 feet) • Did not account for subsurface factors DATA INPUT: DWR GROUNDWATER LEVELS

• Deeper groundwater allows greater capacity for storage • Even with excellent SAGBI scores, shallow groundwater is a concern DATA INPUT: USGS CVHM SEDIMENT DATA • Purpose is to include a deeper sediment analysis • Consider depth (if any) to restrictive horizons or less permeable sediments below the root zone. DATA INPUT: IRRIGATION DISTRICTS, & POINTS OF DIVERSION

• Areas served by water districts are more likely to have infrastructure needed for recharge implementation • Areas solely served by groundwater were assumed to not have supplies SUITABILITY CLASSIFICATION AND RATING

Step 1 Step 2 Limiting Layer Subsurface Sediment Ranking Limiting Groundwater Corcoran Layer Class Class Rank Level Clay Level (ft) CVHM (0-50ft) CVHM (50-150ft) Very Good 6 X 60+ 80-100 80-100 Good 5 40-60 60-80 60-80 Moderately Good 4 X 30-40 40-60 40-60 Moderately Poor 3 20-30 20-40 20-40 Poor 2 10-20 10-20 10-20 Very Poor 1 <10 0-10 0-10 Weight % influence 5 5 4 2 Weighted Score 20 0 16 0

Final Rating Calculation Example: (20 + 16 = 34)/9 = 4.0 GROUNDWATER RECHARGE INDEX RESULTS

SAGBI • Surface soil suitability • Can you infiltrate recharge water? GROUNDWATER RECHARGE SUSTAINABILITY INDEX RESULTS

LAND IQ SUBSURFACE • Subsurface soil suitability • Can you percolate and store recharge water below the crop root zone? GROUNDWATER RECHARGE SUSTAINABILITY INDEX RESULTS

LIMITING INDEX RESULT Groundwater recharge requires suitable conditions in both surface and subsurface soils GROUNDWATER RECHARGE SUSTAINABILITY INDEX RESULTS

COMBINED SUITABILITY INDEX APPLICATIONS OF THE INDEX

Crop specific groundwater recharge suitability

Where are almond orchards with suitable conditions for recharge? APPLICATIONS OF THE INDEX

Crop specific groundwater recharge suitability

• 29% of almond orchards are on soils ranked good to very good for groundwater recharge. ALMOND ACREAGE & GROUNDWATER RECHARGE SUITABILITY

Rank Class Total Acres % of Acres

6 Very Good 4,864 0.5%

5 Good 271,169 28.4%

4 Mod Good 395,735 41.5%

3 Mod Poor 153,934 16.1%

2 Poor 89,817 9.4%

1 Very Poor 39,195 4.1%

Total 954,714 100.0% STATEWIDE LAND USE MAPPING • Over 360,000 individually classified polygons

• 45 crop legend • Major land use categories classified • = 9.4 million acres • Urban = 4.79 million acres • Managed Wetlands = 0.66 million acres CROP AGE DETERMINATION • Once permanent crops are mapped, perform retrospective age analysis • Refined understanding of: • Agricultural practices and recharge potential • Evapotranspiration and applied water • Yield and Biomass, etc. OTHER MAPPING RESOURCES

• Historical & Projected Land Use • Historical, Current & Projected Irrigation Method • Native/Riparian Vegetation Mapping • Crop Evapotranspiration • Native/Riparian Vegetation Evapotranspiration • Root Depth Index QUESTIONS?