Post-Fire Monitoring Update and Preliminary Results LECL TMDL Task - PowerPoint PPT Presentation

Post-Fire Monitoring Update and Preliminary Results LECL TMDL Task Force Meeting February 21, 2019 1

Agenda Holy Fire 1 Sampling Design 2 StormEvents 3 4 Preliminary Results 2

Holy Fire 1 Began on August 06, 2018 Cleveland National Forest 22,877 acres burned • 14% high soil burn severity • 71% moderate burn severity • 15% low soil burn severity Potential Fire Impacts • High debris flows in watersheds with steep slopes and high-to-moderate soil burn severity • Exacerbated debris flows within 1-3 years of the fire Schwartz, J.Y., and T. Stempniewicz. 2018. Burned Area Emergency Response (BAER) Assessment: Geological Hazards. Cleveland National Forest, CA. 3

Sampling Design • Assess the potential impacts of the Holy Fire • Not part of Permittee’s required compliance monitoring • Expedited process to capture ‘first flush’ • Contracting/mobilization/equipment • Feedback from the LECL TMDL Task Force • Followed SMC Post-Fire Water Quality Monitoring Plan: “Effects of Post-fire Runoff on Surface Water Quality: Development of a Southern California Regional Monitoring Program with Management Questions and Implementation Recommendations” (SCCWRP, 2009). http://ftp.sccwrp.org/pub/download/DOCUMENTS/TechnicalReports/598_SoCalRegionalFireMonitorin gPlan.pdf 4

SMC Po Post-Fi Fire W e Water Q Qua uality M Monitoring ng Plan P n Priority M Mana nagem emen ent Q Que uestions ns: How does post-fire runoff affect contaminant flux? 1. 2. What is the effect of post-fire runoff on downstream receiving waters? What are the factors that influence how long post-fire runoff effects persist? 3. Sampling Design to Address Question #1 • Sample post-fire runoff from the terminal end of burned catchments 1 • Downstream of debris basins • Compare the data to reference or control sites • Assess the effects of the Holy Fire: • Hydrologic response • Sediment and pollutant loads 5

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3 Storm Events Event #1 11/29/2018 ‘First Flush’ • McVicker • Horsethief • Adobe Reference Event #2 1/14/2019 • McVicker 1/17/2019 • Horsethief 7

McVicker Debris Basin-Leach Canyon Pre-Storm Post-Storm 10/1/2018 11/30/2018 8

Horsethief Canyon Post-Storm Pre-Storm 11/30/2018 10/1/2018 9

Leach Canyon Dam Post-Storm Pre-Storm 11/30/2018 01/08/2019 10

Lake Elsinore Pre-Storm Post-Storm 01/08/2019 01/18/2019 11

Prel eliminar ary 2. 1. Anal alyte C e Concen entration ons 1 12

Post-Fire Event #1 Post-Fire Event #2 Total Phosphorus Total Phosphorus 11/29/2018 1/14/2019 and 1/17/2019 Total Nitrogen Total Nitrogen 60 60 58 56 56 52 52 48 48 44 44 40 40 36 36 33 32 32 mg/L mg/L 28 28 25 24 24 20 20 16 16 16 16 12 12 9.6 7.3 8 8 4.6 4 4 0.25 0.12 0 0 Adobe McVicker Horsethief McVicker Horsethief Creek Debris Canyon Debris Canyon Reference Basin Basin 13

Total Hardness Post-Fire Event #1 Post-Fire Event #2 Total Hardness Total Dissolved Solids 11/29/2018 1/14/2019 and 1/17/2019 Total Dissolved Solids Total Suspended Solids Total Suspended Solids 140,000 140,000 130,000 130,000 130,000 120,000 120,000 110,000 110,000 100,000 100,000 90,000 90,000 80,000 80,000 mg/L mg/L 70,000 70,000 60,000 60,000 50,000 50,000 40,000 40,000 30,000 30,000 20,000 20,000 16,000 15,000 10,000 6,900 10,000 2,200 1,500 930 ND(<2) 770 830 180 300 290 160 300 0 0 0 Adobe McVicker Horsethief McVicker Horsethief Creek Debris Canyon Debris Canyon Reference Basin Basin 14

Post-Fire Event #1 Post-Fire Event #2 Total Aluminum Total Aluminum 11/29/2018 1/14/2019 and 1/17/2019 Total Iron Total Iron 4,000 4,000 3600 3,600 3,600 3400 3,200 3,200 2,800 2,800 2,400 2,400 mg/L mg/L 2,000 2,000 1,600 1,600 1,200 1,200 800 800 320 400 400 300 97 93 67 74 ND(0.074) 0 0.065 0 0 Adobe McVicker Horsethief McVicker Horsethief Creek Debris Canyon Debris Canyon Reference Basin Basin 15

Post-Fire Event #2 Post-Fire Event #2 Dissolved Aluminum Total Aluminum 1/14/2019 and 1/17/2019 1/14/2019 and 1/17/2019 Dissolved Iron Total Iron 360 360 320 320 320 300 280 280 240 240 200 200 mg/L mg/L 160 160 120 120 74 80 80 67 ND (<0.037) ND (<0.037) 40 40 0.015 0.015 0 0 0 0 McVicker Horsethief McVicker Horsethief Debris Canyon Debris Canyon Basin Basin 16

Post-Fire Event #1 Post-Fire Event #2 Total Manganese 11/29/2018 Total Manganese 1/14/2019 and 1/17/2019 225 225 210 200 200 175 175 150 150 125 125 mg/L mg/L 100 100 75 75 50 50 25 25 7 9.3 0.017 3.3 0 0 Adobe McVicker Horsethief McVicker Horsethief Creek Debris Canyon Debris Canyon Reference Basin Basin 17

Post-Fire Event #1 Total Cadmium Post-Fire Event #2 Total Cadmium 11/29/2018 1/14/2019 and 1/17/2019 Total Copper Total Copper Total Lead 10 Total Lead 10 Total Nickel Total Nickel 9.5 9.5 Total Zinc Total Zinc 9 9 8.5 7.9 8.5 8 8 7.5 7.5 7 7 6.5 6.5 5.7 6 6 5.1 5.5 5.5 mg/L mg/L 5 5 4.5 3.9 4.5 4 4 3.5 3.5 3 3 2.5 2.5 2 1.7 2 1.5 ND(0.00012) 1.5 ND(0.0002) 0.73 0.68 1 1 0.45 0.0062 0.0038 0.0015 0.0019 0.2 0.12 0.045 0.3 0.0017 0.5 0.033 0.21 0.064 0.2 0.024 0.013 0 0 0.5 0 0 Adobe McVicker Horsethief McVicker Horsethief Creek Debris Canyon Debris Canyon Reference Basin Basin 18

Post-Fire Event #2 Post-Fire Event #2 Total Cadmium Dissolved Cadmium 1/14/2019 and 1/17/2019 1/14/2019 and 1/17/2019 Total Copper Dissolved Copper Total Lead Dissolved Lead 2 2 Total Nickel Dissolved Nickel Total Zinc Dissolved Zinc 1.8 1.8 1.7 1.6 1.6 1.4 1.4 1.2 1.2 mg/L mg/L 1 1 0.8 0.8 0.6 0.6 0.45 0.4 0.4 0.3 ND (<0.00012) ND (<0.00012) ND (<0.0002) 0.21 ND (<0.0002) 0.2 0.2 0.2 0.064 0.0044 0.0016 0.0028 0.033 0.0024 0.0018 0.0006 0.0017 0.024 0.013 0 0 0 0 0 0 McVicker Horsethief McVicker Horsethief Debris Canyon Debris Canyon Basin Basin 19

1. How does post-fire runoff affect contaminant flux? Initial Takeaways 2. • High concentrations of sediment, nutrients, and metals • Significantly higher than reference data • Concentrations lower in Event #2 • Debris basins reduced downstream impacts Post-Fire Monitoring Report (expected May/June 2019) • Assessment of post-fire contaminant and flux • Pollutant concentrations 1 • Flow data • Event-based sediment and pollutant loads • Comparison with reference data 20

THANK YOU! Rebekah Guill Stormwater Monitoring Program Manager Riverside County Flood Control and Water Conservation District rguill@RIVCO.ORG Garth Engelhorn, CPSWQ, QISP/Tor Project Manager-Primary Point of Contact Garth.Engelhorn@altaenviron.com David S. Renfrew, PMP, CPSWQ, QISP/Tor, QSD Director of Water Resources, Vice President David.Renfrew@altaenviron.com 21