everglades west coast total maximum daily load (tmdl) reports (dissolved oxygen) 2008

Everglades West CoastTotal Maximum Daily Load (TMDL)

Reports (Dissolved Oxygen)2008

Dissolved Oxygen* TMDLs Completed this Year (2008)

Highest Priority to 1998 303D List

• Hendry Creek (WBID 3258B) & Hendry Creek Marine (WBID 3258B1) DO TMDL

• David Tyler and Kyeongsik Rhew

• Imperial River (WBID 3258E) DO TMDL• Kristina Laskis, Nathan Bailey, and Rob McTear

• Gordon River Extension DO TMDL(3278K)• Nathan Bailey

*Note: Dissolved Oxygen TMDLs Typically Focus on Reduction of causative pollutants TN, TP, and/or BOD

HendryCreek Marine:6,920 acre WBID

HendryCreek:533 acre WBID

ImperialRiver:5,873 acre WBID

Gordon RiverExtension:5,154 acre WBID

Lee County

Collier County

Approx. 6 miles long

Land Use Overview

Landuse Description

Hendry3258B

Hendry M3258B1

Imperial3258E

Gordon3278K

Acres % Acres % Acres % Acres %

Urban and Built up 336 63 1,730 25 1,884 32 3,602 70

Agriculture * * 267 4 187 3 57 1

Rangeland 17 3 267 4 511 9 193 4

Upland Forests 83 16 1,056 15 393 7 453 9

Water 12 2 531 8 232 4 194 4

Wetland 39 7 2,949 43 2,452 42 48 9

Barren Land * * 19 0 54 1 22 0

Transportation, Communication,

& Utilities 45 9 98 1 158 3 147 3

Total 533 100 6,920 100 5,873 100 5,154 100

WBID: Hendry Creek

Imperial River

Gordon River Extension

Hendry Creek Marine

Class. 3F 3M

DO

Dissolved Oxygen shall not be less than 5 mg/L; this includes normal daily and seasonal fluctuations.

Shall not average less than 5.0 mg/L in a 24-hour period and shall never be less than 4.0 mg/L. Normal daily and seasonal fluctua tions above these levels shall be maintained.

BODShall not be increased to exceed values which would cause dissolved oxygen to be depressed below the limit established for each class and, in no case, shall it be great enough to produce nuisance conditions.

Nutrients

In no case shall nutrient concentrations of a body of water be altered so as to cause an imbalance in natural populations of aquatic flora or fauna [Note: For Class III waters in the Everglades Protection Area, this criterion has been numerically interpreted for phosphorus in Section 62-302.540, F.A.C.].

Assessment of TMDL Streams for DO

Waterbody

Total #

of Samples

IWR Required Exceedances

for impairment

Total Number of

Exceedances

(and %)

Conclusion

Hendry Creek Marine

39 7 34 (87%) Impaired

Hendry Creek 59 10 31 (53%) Impaired

Gordon River

Extension72 12 70 (97%) Impaired

Imperial River 99 15 77 (78%) Impaired

Developing Nutrient Criteria for Rivers and Streams (EPA’s Technical Guidance Manual)

Two ways of Establishing a Reference ConditionMethod 1

• Choose the upper 25th percentile (75th percentile) of a reference population of streams. This is the preferred method to establish a reference condition.

• The 75th percentile was chosen by EPA since it is likely associated with minimally impacted conditions, will be protective of designated uses, and provides management flexibility.

Developing Nutrient Criteria for Rivers and Streams (EPA’s Technical Guidance Manual)

Two ways of Establishing a Reference ConditionMethod 2

• When reference streams are not identified, the second method is to determinethe lower 25th percentile of the population of all streams within a region.

• The 25th percentile of the entire population was chosen by EPA to represent asurrogate for an actual reference population.

(Data analyses to date indicate that the lower 25th percentile from an entire population roughly approximates the 75th percentile for a reference population)

References:• NYSDEC (New York State Department of Environment and Conservation). 2000. Memorandum from Scott

Kishbaugh to Jay Bloomfield, September 26, 2000, regarding reference lakes for nutrient criteria.• TNDEC (Tennessee Department of Environment and Conservation). 2000. Letter to Geoff Grubbs, October

5, 2000, containing comments on draft nutrient criteria recommendations.• U.S. EPA. 2000a. Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs, U.S. Environmental

Protection Agency, Washington, DC. EPA-822-B00-001.• U.S. EPA. 2000b. Nutrient Criteria Technical Guidance Manual: Rivers and Streams, U.S. Environmental

Protection Agency, Washington, DC. EPA-822-B00-002.

Criteria for “Reference” Waterbodies

• Waterbody in Everglades West Coast in Region of Impaired

• Waterbody of Same Class as Impaired• Waterbody has “Not Impaired” status for DO• If there are no bodies meeting No. 3,

Waterbody, has “Not Impaired” status for Chl_a

• Whether using 3 or 4, waterbody cannot have annual average Chl_a above 6.0 ug/L

FDEP’s Reference Approach in Everglades West Coast

FOR ‘SWIMMABLE-FISHABLE’ FRESH WATER WBIDS (3F)• Utilize Method 1 for the Fresh Water Streams where there are more WBIDs which

satisfy all pre-determined high criteria for Reference Stream (Consistent with Method 1, we use the 75 Percentile level as the reference condition.)

FOR ‘SWIMMABLE-FISHABLE’ MARINE WBID (3M) • Utilize a More Conservative Modification of Method 1 because there are no WBIDs

completely meeting Reference Criteria, but there is a nearby area (WBID 3258A) that satisfies most pre-determined criteria for Reference. The main divergence is that 3258A has urban-built-up above 10%. (Thus for MARINE WBID (3M) we will use the Median of the Reference waterbody as the reference condition).

Hendry Creek Marine& Estero Bay Wetland (Reference WBID)

Imperial River, Gordon River Extension & Reference WBIDs

WBID

Parameter of

Concern

Number of

Samples

MedianConcentration (mg/L) During

Verified Period

Local Reference Concentration

(mg/L) 75th Percentile (3F)

Median (3M)

Imperial River

BOD5 88 1.2 1.85

TN 98 0.94 0.76

TP 78 0.039 0.04

Gordon River Exten-sion

BOD5 17 2 1.85

TN 60 0.89 0.76

TP 66 0.07 0.04

Hendry Creek

BOD5 29 1.5 1.85

TN 30 0.78 0.76

TP 29 0.03 0.04

Hendry Creek Marine

BOD5 67 1.3 1.3

TN 67 0.89 0.6

TP 48 0.0535 0.057

Subsequent Efforts to identify Causative Pollutants involve looking at relationships between DO and Potential Causative

TN vs DO Estero Bay Estuary

y = -0.4495Ln(x) + 1.4593

R2 = 0.2885

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000 9.000

DO Concentration

TN

Co

nce

ntr

atio

n

TN MEDIAN

Log. (TN MEDIAN)

Freshwater Stations > 20 Observations

Station Medians during Verified Period Freshwater Estero Bay Stations w ith more than 20 observations

y = -0.0511x + 1.1004

R2 = 0.24

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000

DO (mg/L)

TN

(m

g/L

)

Station Medians during Verified Period Estuary Estero Bay Stations w ith more than 24 observations

y = -0.1077x + 1.2657

R2 = 0.42

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000

DO (mg/L)

TN

(m

g/L

)Marine Stations with more than 24 Observations

FRESH WATER STREAM SAMPLE STATION MEDIAN CONCENTRATIONS(In FDEP TMDL Southwest Coast Planning Unit, For Sampling during Cycle 2 Verified Period)

Linear Regression Equation: Dissolved Oxygen = -4.9948 TN + 8.0762 R2 = 0.4597

0

1

2

3

4

5

6

7

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Total Nitrogen, mg/L

Dis

solv

ed O

xyg

en, m

g/L

Sample Station Median Linear (Sample Station Median)

Fresh Water Stream Sample Station in Estero Bay Median TN Concentrations during Verified Period

HendryCreek

&HendryCreekMarineSampleStations

ImperialRiver

SampleStations

GordonRiver

ExtensionSampleStations

Percent Reduction = [Measured Exceedance – TN Target] * 100 Measured Exceedance

Percent Reduction for Total Nitrogen

Sample Date Station Observed TN Value (mg/L)

Target Concentration

(mg/L)

% Reduction

1/13/200021FLEECOHENDG

R110.98 0.64 34.69


R200.73 0.64 12.33


R111.02 0.64 37.25


R200.85 0.64 24.71


R111.35 0.64 52.59


R200.74 0.64 13.51


R111.4 0.64 54.29


R111.11 0.64 42.34


R111.06 0.64 39.62


R200.83 0.64 22.89

Final Percent Reduction is Median of Percent Reductions for all samples collected during Verified Period

etc.

TMDL WLAs Wastewater + WLAs NPDES Stormwater + LAs + MOS

WBID

TMDLTotal

Nitrogen(mg/L)

WLA LA Reduction

MOSWastewater (lbs/year)

NPDES Stormwater(Percent Reduction)

Imperial River

0.76 N/A 22 % 22 % Implicit

Gordon River

Extension0.76 N/A 29 % 29 % Implicit

Hendry Creek

*0.6 N/A * 44% * 44 %Implicit

Hendry Creek Marine

0.6 N/A 44 % 44 %Implicit

Maximum Daily Loads for Total Nitrogen for the DO Impaired WBIDs (based on Reference 75th Percentile)

* Required to protect downstream marine segment

Recommendations

• Commence collection of stream flow data on Hendry Creek Marine, Imperial River, and the Gordon River Extension throughout the dry and wet seasons.

• Increase water quality sampling in those stations where there are higher concentrations.

• Utilize water quality computer models to simulate the watershed hydrology to increase understanding of the factors contributing to impairment conditions.

• Sample ground water quality and monitor ground water contribution to stream flow.

It is recommended that the following activities occur to advance the goals of the TMDLs described;

Pat Fricano Nathan BaileyBureau of Watershed Management Bureau of Watershed Management Watershed Planning and Coordination Watershed Assessment Section

(850) 245 - 8559 (850) 245 - [email protected] [email protected]

MORE INFORMATIONFDEP Websites:

TMDL Program Website: http://www.dep.state.fl.us/water/tmdl/index.htm

Basins 411 Website: http://www.floridadep.org/water/basin411/default.htm

Florida Department of Environmental Protection

David Tyler Kyeongsik RhewBureau of Watershed Management Bureau of Watershed Management Watershed Assessment Section Watershed Assessment Section

(850) 245 - 8559 (850) 245 - [email protected] [email protected]

Kristina Laskis Jan Mandrup-PoulsenBureau of Watershed Management Bureau of Watershed Management

Watershed Assessment Section Watershed Assessment Section(850) 245 - 8559 (850) 245 - 8465

[email protected] [email protected]

PUBLIC COMMENTS

The Everglades West Coast Basin

Extends North from Everglades National Park to southern edge of the Caloosahatchee River Basin.

Extends East from the Gulf of Mexico to the western edge of Dade and Broward Counties.

Includes southern Lee and Hendry Counties, all of Collier County, and very small portions of western Dade, Broward, and northern Monroe Counties.

EWC Basin is Subdivided into 3 Planning Units • Estero Bay (20 WBIDs)• Southwest Coast (49 WBIDs)• Interdrainage Area (11 WBIDs)• TOTAL OF 80 WBIDs (Including Coastal WBIDs)

Fresh Water Reference Locations

Marine Reference Waterbody: Estero Bay Wetland

Therefore Target Concentrations were determined to be…

• For TP, the consistently low concentrations throughout the waterbodies was argument against setting TP target

• For TN, based on reference waterbodies and regression analysis, a TN Target Concentration of 0.76 mg/L for Fresh Water and 0.6 mg/L for Marine Segments was set

• The median BOD5 of Reference Waterbodies was 1.85 mg/L (fresh water) and 1.7 mg/L (Marine Water), generally higher than the median BODs for the Impaired WBIDs.

everglades west coast total maximum daily load (tmdl) reports (dissolved oxygen) 2008

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