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Lake Mead

Quagga Mussels in Southern Nevada David Johnson, Treatment Manager Southern Nevada Water System July 15, 2008. The Southern Nevada Water Authority is a regional water agency that provides drinking water to 2 million people and 40 million annual visitors.

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Lake Mead

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  1. Quagga Mussels in Southern NevadaDavid Johnson, Treatment Manager Southern Nevada Water SystemJuly 15, 2008

  2. The Southern Nevada Water Authority is a regional water agency that provides drinking water to 2 million people and 40 million annual visitors. • The SNWA operates two treatment plants with a combined production capacity of 900 MGD.

  3. North LasVegas Nellis Las Vegas Valley Water District Lake Mead AMSWTF Intake 1 Intake 2 Henderson RMWTF Boulder City • Southern Nevada Water Authority System North South

  4. The SNWA’s raw water infrastructure, which is susceptible to quagga infestation, includes: • Five Pumping Stations • 20 Miles of Tunnels and Pipelines • Pressure and Instrument Sensing Line • Surge Systems • Pump Motors • Cooling Systems

  5. Existing Intake Features Proposed Intake No. 3 Features Lake Mead June 2006 Preliminary Concepts To RMWTF IPS-2 1000 ft Control Gate Forebay To AMSWTF IPS-1 1000 ft North Forebay Boulder Harbor Interconnection Saddle Island To AMSWTF IPS-3 860 ft Saddle Island Control Gate Forebay ~ 3 miles

  6. Risk Analysis by RNT Consulting

  7. Lake Mead’s warm temperatures allow quaggas to multiply far more quickly than in the Great Lakes. • Veligers (free floating) into treatment plant • Maximum – 98 Billion/Day • Average – 22 Billion/Day • Attached mussels near intake • 137,000/m2 • Without intervention, quaggas could decimate Southern Nevada’s drinking water infrastructure.

  8. Chlorine is effective at controlling quagga mussels. • However, it may not be a viable long-term solution because of: • Safe Drinking Water Act regulations related to chlorination byproducts • Equipment limitations and maintenance

  9. Additional measures currently being taken by the SNWA include: • Installation of new chemical injection points • Evaluation of alternative control strategies • Installation of control strategies at new intake and pump station

  10. Both temporary and permanent quagga management strategies have significant financial ramifications. • Temporary Measures • Capital - $5 Million • Permanent Measures • Capital - $24 Million • Annual O&M - $1 to 4 Million

  11. Research Needs Workshop • Sponsored by Awwa Research Foundation, Metropolitan Water District of Southern California, and SNWA • Thirty-two invited guests developed research needs – 14 experts and 18 agencies • Three research topics • Chemical Inactivation and Barriers • Population Management • Standard Methods – QA/QC

  12. Research Needs Identified – Chemical Inactivation and Barriers • Determination of Viability in Quagga Mussel Veligers and Assessments of Chemical Treatment Efficacy • Hydraulic Effects on Veliger Mortality in Engineered Systems • Quagga Mussel Vulnerability Assessment and Response Management Tool Development

  13. Research Needs Identified – Chemical Inactivation and Barriers • Demonstrate Alternative, Non-Chemical Control Technologies for Quagga Mussels for Deployment at Water Treatment Facilities • Molluscicides and Biocides for Control of Dreissenid Mussels in Water Resources • Coatings and Materials for Control of Dreissenid Mussel Attachment in Water Resource Projects

  14. Research Needs Identified – Population Management • Response of Quagga Mussel Veligers to Limnological Variables • Application of Biological Agents to Control Quagga Mussels • Applying Knowledge of System Ecology as a Control Strategy • Quantitative Tools for Management of Mussels in the Colorado River System

  15. Research Needs Identified – Population Management • Quantitative Evaluation of Quagga Mussel Outreach and Education Activities • Shifts from Planktonic to Benthic Regimes in Response to Quagga Mussel Invasion • Early Detection Methodology and Rapid Assessment Protocols for Quagga Mussels • Impact of Quagga Mussel Invasion on the Quality of Domestic Water

  16. Research Needs – Standard Methods QA/QC • Decision to work with Standard Methods to develop methods to be published in “Standard Methods for the Examination of Water and Wastewater” • Enumeration • Adults • Veligers • Sampling • Adults • Veligers • Early Warning • Substrate samplers • Polymerase Chain Reaction (PCR)

  17. The Southern Nevada Water Authority and Metropolitan Water District of Southern California on May 15 and June 24, 2008 urged Congress to: • Invest in research related to effective quagga eradication or management methods ($20 Million) • Lead and coordinate efforts by stakeholder agencies

  18. Questions?

  19. Expert Presentations • Quagga Mussels in the West • Optimizing Chemical Disinfection for Dreissenid Mussels • Control of Dreissenid Mussels by Chemical Oxidants • Freshwater Bivalve Infestations: Risks to Assets and Available Control Options 5. Dreissenid Mussel Control for Large Flow, Once Through Systems 6. Dreissena’s in Warm Water 7. Threat of Dreissenid Mussels to Reclamation Water Systems

  20. Expert Presentations • Quagga and Zebra Mussels: Patterns of Reproduction • Invasive Mussel Tracking and Monitoring in Lakes • Quagga Mussel Population Behavior • Role of Modeling in Assessment and Management of Quagga Mussels • Winter Lake Drawdown as a Strategy for Zebra Mussel Control: Results of Pilot Studies in Minnesota and Pennsylvania 13. Dreissenid Mussels in Riverine Ecosystems

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