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Michael Suplee, Ph.D. MT Department of Environmental Quality Water Quality Standards Section

Numeric Nutrient Standards for Surface Waters of Montana. Michael Suplee, Ph.D. MT Department of Environmental Quality Water Quality Standards Section March 1, 2007. Why Numeric Nutrient Standards for Surface Waters?.

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Michael Suplee, Ph.D. MT Department of Environmental Quality Water Quality Standards Section

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  1. Numeric Nutrient Standards for Surface Waters of Montana Michael Suplee, Ph.D. MT Department of Environmental Quality Water Quality Standards Section March 1, 2007

  2. Why Numeric Nutrient Standards for Surface Waters? • Nationally, nutrient enrichment ranks among the top causes of water resource impairment • MT narrative standard: “state waters must be free from substances….that will: (e) create conditions which produce undesirable aquatic life” (ARM 17.30.637) • Can affect DO. DO must not be reduced below class specific criteria (e.g., ARM 17.30.623 [b]) • State-of-the-science is such that developing numeric criteria appears feasible

  3. Clark Fork River above The Little Blackfoot R., July 2004 Yellowstone River @ Miles City, August 2006

  4. EPA National Strategy for Numeric Nutrient Standards “EPA expects all States and Tribes to adopt and implement numerical nutrient criteria into their water quality standards by December 31, 2003.” Federal Register, June 25, 1998

  5. EPA National Strategy for Numeric Nutrient Standards • November 2001: EPA softened its 2003 adoption expectations • States develop plans/schedule for nutrient standards adoption • States conduct scientific studies at the State/regional level • About half of States planning to adopt numeric nutrient criteria in 2008

  6. Presented to WPCAC, April 2001

  7. Setting Up a Geospatial Framework • Nutrient concentrations vary naturally — geology, soils, climate, vegetation • DEQ needed a practical, easy-to-apply geospatial framework that explained a good proportion of nutrient-concentration variability in surface waters • Ecoregions (developed by Jim Omernik) • Lithology • Strahler Stream Order

  8. Level III Ecoregions of MT (Woods et al. 2002)

  9. USGS Geology Map of Montana (1955)

  10. Strahler Stream Order 1 1 1 1 1 1 1 1 2 1 2 2 2 3 3 1 4

  11. Conclusions • As a geospatial framework, level III & IV ecoregions outperformed lithology and stream order, in terms of statistical significance of measures of variation • Ecoregions explained a sufficient degree of nutrient variability that they may be used as a basis to establish criteria in Montana

  12. Determining Criteria • Criteria based on concentrations where beneficial-use impacts begin to occur • Recreation • Fisheries • Impact thresholds are determined using: • stressor-response studies (e.g., TN vs. DO correlation) • Reference stream data (sites with minimal impacts) • nuisance algae public opinion surveys

  13. Study of prairie streams in Northeastern Montana, 2001-2004

  14. Desirable? Desirable?

  15. Bottom Line on the Draft Criteria • Nutrient concentrations that protect uses are low Typical concentrations: • Total P: 0.05 mg/L • Total N: 0.3 mg/L • Difficult for current waste-water technologies to meet criteria • Low-flow streams, limited dilution

  16. Economic Considerations • Federal regs not intended to result in WQ standards so stringent that compliance would cause severe economic impacts on a community • Federal law requires economic impact to be “substantial” and “widespread” • For treatment beyond technology-based regulations • CWA Options: remove use, create use subcategories, do a variance • 75-5-301 (2) (a), § MCA: formulate and adopt standards of water quality, giving consideration to the economics of waste treatment and prevention.

  17. Economic Considerations-Example • Philipsburg, Montana • 930 people • Aging lagoon-based treatment system, can’t accommodate more growth • periodically out of compliance • New mechanical plant (BNR) and clean-up of lagoons: $6,131,987.00 • Per-household sewer rates would rise from ~$15/month to > $70/month

  18. Economic Considerations-Screening Step 1: EPA recommends the “Municipal Preliminary Screener” ; meets substantial test Municipal Preliminary Screener (MPS) = Mean total pollution control cost per household / median household income • MPS < 1% : Cost bearable, no further analysis • MPS 1-2%: Midrange impacts; further analysis possible • MPS > 2%: Unreasonable cost expected for many households • EPA Break points are recommendations; alternatives exist Step 2: Carry out widespread tests (methodology not explicit)

  19. Economic Considerations • DEQ wants to set up committee to evaluate & determine “how expensive is too expensive?” • WQ regulators • Economist(s) • Special interest groups • Affected parties • DEQ will later present this committee’s conclusions to WPCAC

  20. Wrap-Up • EPA continues to expect States to adopt numeric nutrient criteria into their water quality standards • DEQ continues to carry out studies to determine impact thresholds of nutrients on beneficial water uses (recreation, fisheries, aquatic life) • Draft criteria concentrations low; cost of treatment could be high • DEQ is planning to assemble a committee to evaluate “how expensive is too expensive?”

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