alabama’s nutrient criteria development 2012 annual meeting of the swpba november 16, 2012
TRANSCRIPT
Overview
• Goals of Nutrient Program• Alabama Implementation Schedule and Timelines• Tallapoosa River Basin Numeric Nutrient Criteria Study• Weeks Bay Numeric Nutrient Criteria Study• Gulf of Mexico Alliance Update
Goals of Nutrient Program
• ADEM’s goals are consistent with the Clean Water Act and EPA’s National Nutrient Strategy1. Develop and adopt nutrient criteria that support the beneficial uses designated for each
waterbody and that protect these waters from potential adverse effects associated with nutrient over-enrichment
2. Restore and maintain the chemical, physical, and biological integrity of each waterbody
3. Maintain the diversity and uniqueness of Alabama’s waterbodies
• Department’s rationale: establish nutrient criteria consistent with the “fishable/swimmable” goal of the Clean Water Act
Nutrient Criteria Implementation Schedule for the Waters of Alabama
Task/Description Date
Present proposed nutrient criteria for Frank Jackson, Bear Creek, Upper Bear Creek, and Woodruff Reservoirs to the AEMC
2013
Propose nutrient criteria for remaining rivers and streams, where necessary
2015
Propose nutrient criteria for estuarine and coastal waters not previously addressed, where appropriate
2015
Propose nutrient criteria for selected nutrient-sensitive wetlands 2016
Nutrient Criteria Implementation Schedule for Lakes and Reservoirs
Year Number of Reservoirs Major Basin(s) Name of Reservoirs
2001 4 Chattahoochee, Coosa, Tallapoosa West Point, W.F. George, Weiss, R.L. Harris
2002 9 Tallapoosa, Tennessee Martin, Yates, Thurlow, Guntersville, Wheeler, Wilson, Pickwick, Little Bear, Cedar
2004 11 Alabama
Black Warrior
Chattahoochee
Perdido-Escambia
Claiborne, Dannelly
Bankhead, Holt, Lewis Smith, Oliver, Tuscaloosa, Warrior
Harding
Gantt, Point A2005 5 Black Warrior
Perdido-Escambia
Lower Tombigbee
Upper Tombigbee
Inland
Jackson
Coffeeville
Demopolis, Gainesville2010 8 Cahaba
Coosa
Escatawpa
Upper Tombigbee
Purdy
Jordan, Lay, Logan Martin, Mitchell, Neely Henry
Big Creek
Aliceville2013 4 Alabama
Perdido-Escambia
Tennessee
Woodruff
Frank Jackson
Bear Creek, Upper Bear Creek
Tallapoosa River Basin NNC Study
• Goal: Develop numerical nutrient criteria (P & N) for wadeable streams • Data collected by ADEM and GSA; Study by AU Water Resources Center
– Data collected at 34 sites during 2010 growing season– Data statistically analyzed using CART analysis
• CART results – TP was nutrient driving changes in response variables for both
reservoir embayment and streams/rivers– Increased TP observed with decreased photic and Secchi depths,
increased Chl a, decreased fish species and Index of Biotic Integrity• Conclusion: More data will need to be collected and analyzed over several
years to better define actual causal relationships. Limit stream order and focus on sampling small streams to more clearly define nutrient/biota interactions.
Weeks Bay NNC Study
• Goal: Develop appropriate and protective nutrient criteria for estuaries.• Study by TetraTech
– Data collected at 13 stations in 2011; Weeks Bay, Bon Secour Bay, Fish River, Magnolia River, Cowpen Branch, and Polecat Creek
• Regression analyses reveal nitrogen and phosphorus associated with spectrophotometric Chl a concentration in the bay; TN is better predictor than TP
• Recommendations1. Daily minimum DO: not to be <5 mg/L, 50% of time during summer when daily mean
temperature is above 20°C
2. 25 µg/L fluorometric Chl a (EPA and NERRS long-term monitoring) recommended to control mag and freq of hypoxia stress on aquatic life
3. Spectrophotometric Chl a (ADEM) annual geometric mean Chl a <6.4 µg/L and Summer geometric mean Chl a <9.1 µg/L
4. Recommended NC: TP <0.09 mg/L & TN <1.5 mg/L • Determined by multiple regression model when mean relationship between TN and TP is assumed and Chl a
criterion = 9 µg/L • Values should be updated following subsequent data collections in Weeks Bay system and analyses relating them
to those of other G of M estuaries.
Weeks Bay NNC Study
• Conclusion: further studies necessary to explore true causal relationship between nutrient input from upstream sources, resulting algal blooms within Weeks Bay; thus enhancing scientific defensibility of NC.
Gulf of Mexico Alliance
• GOMA Conference held June 19-21, 2012 in Corpus Christi, TX• Ongoing nutrient studies (NSFTE): St. Louis Bay, MS; Weeks Bay, AL;
Galveston Bay, TX; Mission-Aransas Bay, TX• Continuing to identify environmental or biological indicators that are
sensitive to nutrients• Ongoing communication among Gulf states on nutrient criteria
development efforts• Establish technical workgroup to evaluate appropriate biological
assessment tools, endpoints, and thresholds based on NSFTE studies and other available information
• Develop Gulf-wide classification system for use in criteria development• Current and upcoming research projects to study hypoxia, reduce hypoxia,
and efforts to improve access to hypoxia data
Questions?
Lynn Sisk
Chief of Water Quality Branch
(334) 271-7826
Jennifer Haslbauer
Water Quality Branch
(334) 274-4250
Daniel Saliba
Water Quality Branch
(334) 271-7843