1. Fish Impingement and Survival on “Fish Friendly” Traveling Water Screens Alabama Water Resources Association Conference Orange Beach, Alabama September 07, 2012 Justin B. Mitchell APC Compliance Studies

2. Introduction Impingement- The death of fish and aquatic organisms that are pinned on the cooling water intake structure (CWIS). Impingement- The death of fish and aquatic organisms that are pinned on the cooling water intake structure (CWIS).

3. Impingement

4. Proposed Impingement Rule Section 316(b) of the Clean Water Act Section 316(b) of the Clean Water Act Withdraw >2 MGD from waters of the US Withdraw >2 MGD from waters of the US >25% used for cooling purposes >25% used for cooling purposes Primary Compliance Options: Primary Compliance Options: 1. Cooling Towers 2. Intake velocity <0.5 fps 3. Traveling Screen Modifications and Biological Monitoring Fish Buckets Fish Buckets Fish Return System Fish Return System 48 hr Mortality Limit Criteria: 48 hr Mortality Limit Criteria: Average annual mortality rate <12% Monthly maximum mortality rate <31% Monthly maximum mortality rate <31%

5. Gorgas Steam Plant Walker County, AL Black Warrior River (Mulberry Fork) 1,200 MW 5 generating units FGD (scrubber) 2 separate CWIS Units 6-7 Units 8-10

6. Gorgas Approach SSI Band Screen Retrofit Cost effective, $1.3M Cost effective, $1.3M Operationally feasible Operationally feasible Moribund fish (i.e. fish health) exceptions Moribund fish (i.e. fish health) exceptions Entrapment Entrapment Can this technology achieve the mortality limits? Can this technology achieve the mortality limits?

7. Modified Band Screen with Fish Buckets

8. Low and High Pressure Spray Fish Trough Debris Trough Intake Flow

9. Fish Return and Aquaria System

10. Study Objectives 1. Characterize Fish Impingement Rates Debris trough Debris trough Fish trough Fish trough 2. Evaluate Screen Operational Efficiency 3. Investigate 48 hr Latent Impingement Mortality 4. Examine Rates of Sick or Moribund Fish

11. Impingement Samples Collected to Date Fish Return Trough Fish Return Trough Debris Trough 3 8-hr sample/day 3 8-hr sample/day Day Day Evening Evening Night Night 4 days/week (Jan-Feb) 4 days/week (Jan-Feb) 2 days/biweek (Mar-Jun) 2 days/biweek (Mar-Jun) Total Samples = 72 8-hr samples/trough Total Samples = 72 8-hr samples/trough

12. Species Diversity 5,300 fish 30 species 11 families Recreationally Important spp. Fragile spp.

13. Common Species

14. Shad & Non-shad Composition 80% 0.9% 8% 11%

15. Fish Separation 87.6% 12.4% 92.5% 7.4%

16. Survivability Experimental Design Biweekly Impingement Biweekly Impingement Fish Return Trough only Fish Collection Fish Collection 2 days/week 48 Hourly Latent Impingement Mortality (LIM) Observations 48 Hourly Latent Impingement Mortality (LIM) Observations ShiftMondayTuesdayWednesdayThursdayFriday 0600-1400 Fish Collection & LIM Observations LIM Observations 1400-2200 Fish Collection & LIM Observations LIM Observations 2200-0600 Fish Collection & LIM Observations LIM Observations

17. Other Study Components Water Quality Water Quality Intake Intake Aquaria system Aquaria system CWIS Flow CWIS Flow Circ Pumps On, Unit offline Circ Pumps On, Unit offline Intake Velocity Intake Velocity Weather and River Weather and River Flow conditions

18. 24 and 48 hr Latent Impingement Mortality

19. Fish Health Diagnosis

20. Preliminary Conclusions Impingement comprised mostly of shad Impingement comprised mostly of shad 24 hr and 48 hr Impingement Mortality > 12% Limit 24 hr and 48 hr Impingement Mortality > 12% Limit Shad (89-100%) Shad (89-100%) Non-shad (20-60%) Non-shad (20-60%) Disease prevalence among all survival categories Disease prevalence among all survival categories LIM studies are time and labor intensive LIM studies are time and labor intensive Future Research: Explore ways to optimize impingement survival Future Research: Explore ways to optimize impingement survival

21. Questions? Justin Mitchell (205)664-6184jusmitch@southernco.com