Tina Laidlaw US EPA 1

Transcription

1 Tina Laidlaw US EPA 1

2 Many states have developed approaches for listing waterbodies for nutrient-related impairments based on the narrative standard Existing state approaches are similar to CO s proposal If there is interest in learning more details about a particular State s approach, we can follow-up after this meeting and gather more information. 2

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4 19 states with site specific nutrient criteria Cover a range of waterbody types TN criteria adopted in 11 states 8 states have adopted statewide criteria VT and FL have adopted statewide TN criteria for streams and lakes 4

5 Surface waters shall be free from substances in amounts, concentration, or combinations which produce a predominance of undesirable aquatic growth (CO) Surface waters of the state shall be free from floating, suspended, or submerged matter of any kind in concentrations causing nuisance or objectionable conditions or that may impair designated beneficial uses. (ID) All surface waters at all times and at all places shall be free from substances, materials attributable to municipal, industrial, agricultural and other land practices, that are in concentrations or combinations that will cause or contribute to the growth of aquatic plants or algae to such a degree as to (i) create a nuisance, (ii) be unsightly, or (iii) otherwise impair the designated uses. (IN) 5

6 "Nutrient-Related" TMDLs Compared to "Other" TMDLs 18% "Nutrient-Related" Causes of Impairment Compared to "Other" Causes of Impairment on 303(d) Lists 21% 82% Nutrient-Related TMDLs Other TMDLs 79% Nutrient-Related Causes of Impairment Other Causes of Impairment Of the ~71,000 waterbody-pollutant combinations listed nationally, over 15,000 (21%) can be categorized as nutrient-related (defined as nutrients, organic enrichment/oxygen depletion, noxious plants, algal growth, and ammonia ). Of the ~44,000 TMDLs that have been developed nationally, over 8,000 (18%) address nutrient-related causes of impairment. \ Based on CWA Section 303(d) data available in ATTAINS as of March 29,

7 CWA Section 303(d) Program Area Impaired Waters (unique) Streams/ Creeks/ Rivers Lakes/ Reservoirs/ Ponds Bays Coastal Ocean Wetlands Other Nutrientrelated Listings 11,451 7,394 (64%) 2,024 (18%) 1,242 (11%) 128 (1%) 177 (2%) 36 (<1%) 450 (4%) Nutrientsrelated TMDLs 5,198 3,049 (59%) 1,070 (21%) 85 (2%) 10 (<1%) 14 (<1%) 18 (<1%) 952 (18%) Based on CWA Section 303(d) data available in ATTAINS as of March 29,

8 Number of CWA Section 303(d) Listed Nutrientrelated Waterbody-pollutant Combinations by Region & State R1: 1,309 (9%) R2: 687 (4%) R3: 3,895 (25%) R4: 2,564 (17%) R5: 2,213 (14%) R6: 720 (5%) R7: 1,278 (8%) R8: 740 (5%) R9: 895 (6%) R10: 1,004 (7%) 0 to 10 nutrient-related listings (5) 10 to 100 nutrient-related listings (23) 101 to 300 nutrient-related listings (14) 301 to 500 nutrient-related listings (5) 501 to 1,000 nutrient-related listings (6) 1,000 to 2,000 nutrient-related listings (3) Based on CWA Section 303(d) data available in ATTAINS as of March 29, 2011 Alaska Hawaii CNMI Guam American Samoa Virgin Islands Puerto Rico

9 Number of CWA Nutrient-related TMDLs by State R1: 282 (4%) R2: 505 (6%) R3: 1,704 (21%) R4: 1,674 (21%) R5: 782 (10%) R6: 437 (5%) R7: 753 (9%) R8: 791 (10%) R9: 314 (4%) R10: 767 (10%) 0 to 10 nutrient-related TMDLs (8) 10 to 100 nutrient-related TMDLs (24) 101 to 300 nutrient-related TMDLs (14) 301 to 500 nutrient-related TMDLs (8) 501 to 1,000 nutrient-related TMDLs (2) Based on CWA Section 303(d) data available in ATTAINS as of March 29, 2011 Alaska Hawaii CNMI Guam American Samoa Virgin Islands Puerto Rico

10 Single Indicator/ WOE/Flow Chart (sequential) Some states relied on single indicators for listings (e.g., chla, numeric nutrient threshold) Absent criteria, impairment thresholds may be identified Weight-of-evidence approach Weighting different indicators as primary and secondary tiers Followed a sequential approach (e.g., flow diagram) Impairment tied to exceeding 2-3 indicators In general, states use a combination of causal and response variables 10

11 Flow Chart Example 11

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15 Indiana Total Phosphorus data Nitrogen (measured as NO 3 + NO 2 ) Dissolved oxygen ph measurements Excessive Algal Conditions 15

16 In general, states used the following approaches for listing waters for nutrients: evaluation against DO criteria (lakes); comparison to biological thresholds; and/or use of numeric water quality thresholds 16

17 Biological Assessments Macroinvertebrates Often cited cause unknown May use indices Some states use individual metrics Algae Diatom metrics Biofilm % algal cover Aquatic macrophytes Fish 17

18 Chl Concentrations Visual Assessments Comparison to threshold Nutrient thresholds TP TN BOD DO concentrations/flux Bacterial patches / slime Photo by Nashville EFO 18

19 Chlorophyll measurements (avg., max) Trophic State Index (TSI) Secchi depth Blue-green algae Dominance Presence/ abundance of nuisance types Concentrations Duration and frequency of blooms Photo credit: Larry Dupont, VT CAC 19

20 ph DO concentrations Fish Kills Water Quality Trends 20

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23 Ohio TIC = P chla + P DO + B + N Metric P chla P DO Description Representative benthic chlorophyll a (scrapings from rocks in stream bed) Minimum & average instream DO; and 24-hour range (max value minus min value) Metric Score* (Default = 1) B Biological survey results 0 6 N TP (total phosphorus) and DIN (dissolved inorganic nitrogen = NH3-N + NOX-N) 0 4 Acceptable >8/9 no nutrient problems Threatened 4/5 to 7/8 enrichment likely now or future Impaired - <3/4 documented enrichment 23

24 Complaints from the public in 2007 concerning algae in the Greenbrier River Narrative standard Conducted a special study 24

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27 Add classification step to refine numeric triggers? Numeric Indicators N P Response Indicators Primary Production Compositional Indicators Functional Indicators Chl a DO Social Values Macroinvertebrates Algae Stream Metabolism Nutrient Limitation Organic Matter Storage Decomposition Mechanistic Models

28 Adding the limiting nutrient will have the greatest affect on algal growth Nutrient Diffusing Substrates (NDS) Control, N, P, & N + P Analyze algal growth under different nutrient additions

29 Stream Metabolism Functional Indicator Indicator Group Thresholds GPP (go 2 /m 2 /day) Good < 6.0 > Fair < 10.0 > Poor ER (go 2 /m 2 /day) Good < 5.0 > Fair < 9.0 > Poor Nutrients increase rates of GPP and ER High rates of GPP and ER lead to more minimum DO impairments Percent DO Exceedance c b a Low Medium High GPP Group c Direct tie to aquatic life uses Percent DO Exceedance a b 0 Low Medium High ER Group

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