Salt & Nutrient Management Plan Pajaro Valley Water Management Agency

1. Salt & Nutrient Management Plan Pajaro Valley Water Management Agency Stakeholder Workshop #2 March 28, 2013

2. Agenda 9 am – 1pm • SNMP Overview (10 min) • Existing Groundwater Conditions (30 min) • Loading Analysis Approach • Nutrient loading risk analysis/findings (1 hr) • Salt loading risk analysis/findings (30 min) • Assimilative Capacity Discussion (15 min) • SNMP Objective Development Discussion (30 min) • Stakeholder Next Steps (10 min)

3. SNMP Development Process

4. Stakeholder Feedback Process • Plan developed in iterative sections • Drafts vetted with stakeholders • Go to PVWMA website for report and Stakeholder comment form http://www.pvwma.dst.ca.us/board-and-committees/salt-nutrient.php • Comments must be submitted in writing, compiled on comment site • Comments due by 04/12/2013 • Responses tracked and available to all

5. Existing PVGB Groundwater Conditions Approach • Analyze existing groundwater data • 295 PVWMA Production & Dedicated Monitoring Wells • 14 City of Watsonville Production Wells • Calculate statistics by site and constituent for the 10-year period: 2002-2011 • Map statistical results and then interpolate the decadal average and maximum concentrations using Inverse Distance Weighted method • To protect the confidentiality of the well owner, results are maps that show interpolated concentration contours, but do not display individual well data

6. Inverse Distance Weighted Method • Predicts values at unmeasured locations based on measured values surrounding the prediction location. • Local influence from measured data diminishes with distance. • Method is being used to develop SNMPs elsewhere in the state.

7. Metered & UnmeteredWells

8. Groundwater Average TDS

9. Groundwater Maximum TDS

10. Groundwater Average Cl

11. Groundwater Maximum Cl

12. Groundwater Average NO3

13. Groundwater Maximum NO3

14. PVGB Groundwater Condition Summary PVGB Area mapped: 67,500 acres

15. SNMP Pollutant Loading Analysis RISK ANALYSIS APPROACH • Relative risk for each primary source • Identify primary factors driving potential loading • Identify available data to inform factor contribution • Categorize relative contribution of sources based on factors in risk matrices • Generate spatially explicit distribution of relative risk within PVGB area.

16. SNMP Pollutant Loading Analysis ADVANTAGES • Relative risk for each primary source • Sensitive to same inputs as complex models, but less debate on accuracy. • Transparent and easy to communicate • Focus confidence on relative risk designations • Informs priority locations/practices where improvements would be most beneficial

17. Nitrogen – NO3 Risk Analysis Relevant components of the NITROGEN CYCLE Atmosphere [N2(g)] Air Pollution [N2O] fixation deposition Stormwater [NH4+, NO3-] denitrification Plants [N organic] runoff Animal waste [NH4+, NO3-] Irrigation water [NH4+, NO3-] mineralization mineralization uptake Septic/sewer systems [NH4+, NO3-] Fertilizer [NH4+, NO3-] Soil [NH4+, NO3-] applications leaks KEY leaching Controllable sources Groundwater [NO3-] Key reservoirs Downgradient migration Upgradient sources process

18. Agricultural Fertilizer NO3 Loading Risk Analysis Factors evaluated • Soil water holding capacity • Land use patterns • Annual irrigation volumes • Amount of N applied as fertilizer Data sources used • NRCS Soil survey • PVWMA Ag crop land use data (2012 and 2011) • PVWMA and MCWRA water usage data and grower surveys • NASS survey data and published literature values

19. Agricultural Fertilizer NO3 Loading Risk Analysis Soil water holding capacity • NRCS data used for 1-100 cm soil depth • 4 categories based on amount of water held by soil, soil texture data and slope • Categories are specific to the diversity of soil conditions within the Pajaro Valley Categories • Low – capacity to hold up to 0.75 AF per acre • Moderate – capacity to hold 0.75 – 1.25 AF per acre • High – capacity to hold 1.25 – 1.5 AF per acre • Very High – capacity to hold 1.5 – 2.3 AF per acre

20. Relative Soil Water Holding Capacity

21. Agricultural Fertilizer NO3 Loading Risk Analysis Land use patterns • PVWMA Ag land use data averaged for 2011 – 2012 • 6 categories based on crop groups specific to agricultural land use within the Pajaro Valley Categories • Vegetable row crops including artichokes, broccoli, cabbage, cauliflower, celery, lettuce, spinach and other leafy greens • Horticulture nurseries including bulb production facilities, cut flower operations, landscape plants and transplant operations • Strawberries • Caneberries • Deciduous trees – orchards • Other agriculture production including vines, grapes and miscellaneous crops

22. PVGB Ag Land Use

23. Agricultural Fertilizer NO3 Loading Risk Analysis Irrigation intensity • PVWMA usage data, MCWRA usage data, and published literature data sources • 3 categories based on range of values by crop group • Categories are specific to the irrigation requirements based on both crop and cool climate within the Pajaro Valley • Individual agriculture operations may have usage patterns different than values used for each crop group Categories • Low – usage of 0.5 – 1.7 AF per acre, such as grapes and orchards • Moderate – usage of 1.8 – 2.3 AF per acre, such as strawberries, caneberries and other acreage on drip irrigation • High – usage of 2.4 – 3.0 + AF per acre, such as double cropped vegetable row crops and other acreage utilizing sprinkler irrigation

24. Irrigation Intensity

25. Agricultural Fertilizer NO3 Loading Risk Analysis Agriculture crop fertilizer use • NASS surveys, PVWMA surveys, and published literature data sources • 4 categories based on a range of values by crop group • Categories are specific to the diversity of crops and the soil fertility conditions within the Pajaro Valley • Individual agriculture operations may have usage patterns different than values used for each crop group Categories • Low – usage of 35 – 75 lbs. N per acre, such as grapes, certain horticultural operations and miscellaneous crops • Moderate – usage of 76 – 149 lbs. N per acre, such as orchards, caneberries • High – usage of 150 – 250 lbs. N per acre, such as strawberries , vegetable row crops and certain horticultural operations • Very High – usage of over 250 lbs. N per acre, as may occur under certain conditions of crop production

26. Fertilizer Intensity

27. Agricultural Fertilizer NO3 Loading Risk Analysis Soil Water Holding Capacity Fertilizer Intensity Irrigation Intensity Based on crop type Agricultural N Risk Matrix

28. Agricultural Fertilizer NO3 Loading Risk Analysis Agricultural N Risk Matrix

29. Agriculture N Risk

30. Septic N Risk Analysis • Factors : presence and soil type • Septic GIS data Monterey and SC Co • Monterey Co data generated using CAD plans by 2N. • 4500 of septic systems in PVWMA • Density exceeds 400 units/sq mi in some locations

31. Septic N Risk Analysis Septic N Risk

32. Sewer N Risk Analysis • Factors : presence and soil type • Sewer GIS data Monterey and SC Co • Monterey Co data generated using CAD plans by 2N. • 146 miles of sewer lines in PVWMA

33. Sewer N Risk

34. Surface water infiltration N Risk Analysis Factors : stream bed conductivity and mean Q3 [NO3]

35. Streamflow Infiltration

36. Surface water infiltration N Risk Analysis Streamflow N Risk

37. Subordinate Sources N loading • Agricultural Irrigation • Potential opportunity to manage fertilizer apps • Similar outcome as fertilizer risk • Riparian land use risk • Buffer approach • Urban storm water runoff • Localized • Low recharge in Sloughs • Atmospheric • Uncontrollable • Animal Waste • Minimal presence

38. N loading ACROSS sources

39. N loading ACROSS sources Agriculture: 1742 t N/yr Mass of N leaching to gw per year per acre * acres of Ag in PVGB 130 lbs N/acre/yrx 26,799 acres of ag • 134 lbs N/acre/yr (Viers et al 2012; study area average) • 123 lbs N/acre/yr (Viers et al 2012; Mo Co area average)

40. N loading ACROSS sources SEWER (67 t N/ yr) • Fraction of N per person lost (1-25%) 25% of 55,000 people waste SEPTIC (66 t N/yr) • Fraction of N per person lost (85%) 16,100 people on septic WWTP (80 t N/yr) • 6.6 million GPD treated, 50% infiltrated @ 16 mg/L NO3 Stream flow recharge (746 t N/yr) • USGS annual recharge (AF/yr) * NO3 SW conc. 18,300 AF/yr * 30 mg/L

41. Salt loading risk analysis Sources in PVGB • Seawater Intrusion • Irrigation practices • Surface water recharge

42. Seawater Intrusion Seawater Intrusion Risk

43. SALT CYCLING ON IRRIGATED LAND Salt content of irrigation water HIGH Low Evapotranspiration HIGH Evapotranspiration Low Irrigation volumes Plant Growth HIGH Plant Growth HIGH Low L Soil SALT adsorption HIGH Soil SALT adsorption Low SALT leaching Low SALT leaching HIGH Aquifer SALT Low Aquifer SALT HIGH

44. Irrigation salt loading risk Factors • Annual water use • Irrigation water TDS content • Soil water holding capacity

45. Irrigation Salt Risk

46. Surface water infiltration SALT Risk Analysis Factors : stream bed conductivity and mean Q3 [TDS]

47. Streamflow Salt Risk

48. Assimilative Capacity Discussion • Required Task of SNMP • Intent of task is to identifyareas of concern and areas where standards are met • No specific GW standards for PVGB • Clarification from Regional Board requested

49. SNMP Objective Development Useful strategy implementation objectives are: • Future vision statements and time frame • Measurable • Used to communicate and track progress toward future vision • Used to guide strategy/project development and prioritization • Used to guide monitoring needs, purpose and use of data

50. Pajaro River Watershed IRWM WQ Goal and Objectives Water Quality Goal: Protect and improve water quality for beneficial uses consistent with regional community interests and the RWQCB basin plan objectives through planning and implementation in cooperation with local and state agencies and regional stakeholders. Water Quality Objectives: • Meet or exceed all applicable groundwater, surface water, wastewater, and recycled water quality regulatory standards. • Identify and address the drinking water quality of disadvantaged communities in the Pajaro River Watershed. • Protect groundwater resources from contamination including salts and nutrients. • Address impacts from surface water runoff through implementation of Best Management Practices or other surface water management strategies. • Meet or exceed delivered water quality targets established by recycled water users.