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Salt & Nutrient Management Plan Pajaro ValleyStakeholder Meeting #2March 28, 2013

1AgendaSNMP OverviewExisting Groundwater ConditionsLoading Analysis ApproachNutrient loading risk analysis/findingsSalt loading risk analysis/findingsAssimilative Capacity DiscussionSNMP Objective Development Discussion

Brian L2SNMP Development Process Primary Tasks ScheduleTask 1. Stakeholder Outreach4 Stakeholder Meetings at critical milestonesTask 2. Conceptual ModelDraft included Task 3. Salt and Nutrient Loading AnalysisDraft included Task 4. Assimilative Capacity EstimateDraft Fall 2013 Task 5. Develop or update objectivesDraft Fall 2013Task 6. Develop or update priority program/projectsDraft Fall 2013Task 7. SNMP Monitoring PlanDraft Fall 2013Task 8. Conduct anti degradation analysisDraft Fall 2013Task 9. Complete SNMPDraft Spring 2014Final Summer 2014Brian L3Stakeholder Feedback ProcessDraft sections iteratively vetted with stakeholdersGo to PVWMA website for report and Stakeholder comment form

Must be submitted in writing, compiled on comment siteRecommended alternatives requiredComments due by 04/12/2013Responses tracked and available to all

BL4Existing Groundwater ConditionsApproach295 PVWMA Production/Monitoring Wells w/ data14 City of Watsonville Production WellsSummarize samples by site/constituent for 2002-2011Interpolate decadal average and max concentrations using IDW for 5 closest wells (3 wells for max)Results are interpolated concentration contoursBL5

TDSConcentration Rangeacres / % of total0-450 mg/L35,300 / 52%>450 mg/L 1000 mg/L27,900 / 41%>1000 mg/L 1800 mg/L3,550 / 5%>1800 mg/L637 / 1%6

TDSConcentration Rangeacres / % of total0-450 mg/L29,300 / 43%>450 mg/L 1000 mg/L30,500 / 45%>1000 mg/L 1800 mg/L6950 / 10%>1800 mg/L900 / 1%7

ChlorideConcentration Rangeacres / % of total0-100 mg/L55,500 / 82%>100 mg/L 250 mg/L8870 / 13%>250 mg/L 500 mg/L2600 / 4%>500 mg/L644 / 1%8

ChlorideConcentration Rangeacres/% of total0-100 mg/L52,900 / 78%>100 mg/L 250 mg/L10,400 / 15%>250 mg/L 500 mg/L3170 / 5%>500 mg/L1200 / 2%9

NitrateConcentration Rangeacres / % of total0-10 mg/L25,500 / 38%>10 mg/L 45 mg/L28,400 / 42%>45 mg/L 100 mg/L10,500 / 16%>100 mg/L3260 / 5%10

NitrateConcentration Rangeacres/% of total0-10 mg/L24,600 / 36%>10 mg/L 45 mg/L23,100 / 34%>45 mg/L 100 mg/L12,600 / 19%>100 mg/L7410 / 11%11Groundwater Condition SummaryPVGB Area: 67,500 acresConstituentConcentration ThresholdFraction above threshold AVERAGE (%)Fraction above threshold MAX (%)TDS1000 mg/L611Chloride100 mg/L1822Nitrate-NO345 mg/L213012Loading Analysis ApproachRelative risk for each primary source Utilize available data and applicable literatureMinimize focus on accurate and precise valuesMaximize focus on primary factors driving loadingFocus confidence on relative risk designations to prioritize locations/practices where improvements would be most beneficialNB13Nitrate Loading Risk Analysis

NB14Agricultural N Risk AnalysisAg land use PVWMA 2009, 2011 and 2012 categorize crop typesFertilizer use as N lbs/acre/yr by crop typeData/info usedIrrigation use as ac ft/acre/yr by crop typeData info usedSoil holding capacityNRCS soil survey; relative classificationBP15

Land Use CategoryAcres% of totalArtichokes, Nursery, Vegetable Row17,77825Strawberries5,8988Raspberries and Blackberries3,9776Deciduous (Apple Orchards)2,9144Other, Unknown Agriculture, Vine/Grapes1,7943Fallow or other non-agricultural land uses38,06854Total70,42910016

Annual fertilizer application categoryMeasured(%)Expected (%)Very High0%40%High73%33%Moderate21%21%Low6%6%Total agricultural land use (Acres)32,362Total non-agricultural land use (acres)38,06817

Annual irrigation intensity category%High55Moderate31Low15Total agricultural land use32,362Total non-agricultural land use 38,06818

19Agricultural N Risk Analysis

20Agricultural N Risk Analysis

Agricultural nitrate loading riskAcres% of totalHIGH15,89949MODERATE14,15044LOW2,2967Total agricultural land use32,344100Ag Risk Map21Septic N Risk AnalysisSeptic GIS data Monterey and SC CoMonterey Co data generated using CAD plans by 2N. 4500 of septic systems in PVWMARisk is presence and soil type

22Septic nitrate loading riskNumber of septic systemsSC/Mo%HIGH18891023 / 86642MODERATE21521955 / 19748LOW431311 / 12010Total 4472100Septic N Risk Analysis

Septic nitrate loading riskNumber of septic systemsSC / Mo County% of totalHIGH18891023 / 86642MODERATE21521955 / 19748LOW431311 / 12010Total 447210023Sewer N Risk AnalysisSewer GIS data Monterey and SC CoMonterey Co data generated using CAD plans by 2N. 146 miles of sewer lines in PVWMARisk is presence and soil type

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Sewer nitrate loading riskTotal Length (miles)% of totalHIGH19.413%MODERATE72.750%LOW53.737%Total 145.8100%25Stream Infiltration N Risk AnalysisPlace holder for now. 26Nutrient Loading Risk AnalysisOther SourcesRiparian Zone Land Use RiskBuffer approachUrban Stormwater Runoff

We wont show maps just discuss27N loading across sourcesViers et al 2012 N loading to gw mass balanceEstimate N loading/unit source/yrUse for order of magnitude comparisons for PVGB

28N loading across sourcesAgriculture: 2100 t N/yr Tulare/Salinas 40% high fertilizer demand crops 145 lbs N/acre/yr applied PVGB 85% high fertilizer demand crops 200 lbs N/acre/yr appliedAVE : 134 lbs N/acre/yr leached to groundwater Use 130 lbs N/acre/yr * 32,000 acres of ag29N loading across sourcesSEWER (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 (11 t N/yr) 6.6 million GPD treatedMass Balance: 96% annual nitrate loaded Ag practices

30Salt Loading Risk AnalysisSeawater Intrusion:Developed using GW well Cl concentrations20% of groundwater volumes >100 mg/L ChlorideRisk BoundariesWithin existing seawater intrusion boundary (2011): High Risk0-0.5 miles inland: Moderate Risk>0.5 miles inland: Low Risk

31Salt Loading Risk AnalysisSeawater Intrusion

32Salt Loading Risk Analysis

33Salt Loading Risk AnalysisIrrigation Salt Loading RiskAnnual water useIrrigation water TDS contentWHC

34Salt Loading Risk AnalysisSummary of Findings

Irrigation salt loading riskAcres% of total Ag-LandHIGH8,97828MODERATE13,72143LOW9,24629Total agricultural land use31,945100Non-agricultural land use34,00435Assimilative Capacity DiscussionPotential intent is to identify if places where conditions are perhaps below standards. No specific GW standards for PVGBCurrent areas of known issues Clarify from Regional Board requested36SNMP Objective Development37Final Questions/Comments38