Changes to Regulations

1. Changes to Regulations • Triennial Review • Required by State & Federal Regs • Colorado Process 5 years • Required for; • Basic Standards • Stream Standards • Site Specific Standards • Other regulations

2. Standards implementation Basic Stds Discharge Permit Stream Stds >2008 June 2005 Arkansas River 2008

3. Basic Standards 2005 • New definitions • Effluent dependent stream • Effluent dominated stream • E.coli • Ambient Quality Based Stds. • Clarification (95th percentile) • Temporary Modifications • Clarification (Reg.31 & 61)

4. Basic Standards 2005 cont. • Antidegradation Provisions • Use protected designation • Change methodology • Statewide Standards • Clarification of radionuclide analysis • Add Tributyltin (TBT) • Recreation Classification

5. Basic Standards 2005 Cont. • Temperature Standards • Daily Maximum (“DM”) • Cold 23.8 C • Warm 32.5 C • Cool 29.4 C • Maximum weekly average Maximum temperature (“MWAT”) • Cold 19.3 C • Warm 29.2 C • 24.2 C

6. Basic Standards 2005 Cont. • Ammonia Standards • EPA’s 1999 criteria • New calculation • Total –vs- unionized • Impacts to POTWs • Cold water – some relief • Warm water – more stringent (LOWER NH3)

7. Basic Standards cont. • Metals • Aluminum • Revise based on pH • Arsenic • Acknowledge MCL • Antimony • Eat more fish • Others-

8. Standards implementation Basic Stds Discharge Permit Stream Stds >2008 June 2005 Arkansas River 2008