Minimum Flows and

Levels for the

Peace River

FLOW 2008

October, 2008

Marty Kelly http://www.swfwmd.state.fl.us/projects/mfl/

The Issues that Led to the Instream flows Process/Studies

Shell Creek

Joshua Creek

ArcadiaHorse Creek

Charlie Creek

Zolfo Springs

Bartow

USGS Gage Site

Minimum Flows and Levels - Florida Statutes, Section 373.042 -

The minimum flow for a given watercourse shall be the limit at which further withdrawals would be significantly harmful to the water resources or ecology of the area

The Policy Context

The Science Done

• Flow Regime – Building Block Approach• Benchmark Period • Multiple MFLs - address seasonality• Percent of Flow Reduction Technique• Significant Harm - 15% reduction in

available habitat

Colorado River near Grand Canyon, AZ - Comparison of Median Daily Flow for Three Time Periods (1940-1969 blue,

1970-1994 green, 1995-2005 orange)

0.0000

0.0010

0.0020

0.0030

0.0040

0 100 200 300

Flo

w (

m3

/se

c/k

m2

)

Flow Regime gone Bad

Minimum Flows and Levels

Components of an MFL (from Beecher 1990)

1. a goal – (e.g., non-degradation or, for the District’s purpose, protection from significant harm

2. identification of resources of interest to be protected

3. a unit of measure (e.g., flow in cfs, habitat in useable area, etc.)

4. a benchmark period, and

5. a protection standard statistic.

Peace River at Arcadia - Comparison of Median Daily Flow for Peace River at Arcadia, FL for Three Time Periods (1940-1969 blue, 1970-

1994 green, 1995-2005 orange)

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20

40

60

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100

0 50 100 150 200 250 300 350

Flo

w (

m3/

sec)

Two Benchmark Periods

Blame it on Hal………………

Peace River at Arcadia - Comparison of Mean Daily Flow for Three Time Periods (1940-1969 blue, 1970-1994 green, 1995-2005 orange)

0

20

40

60

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100

120

140

0 50 100 150 200 250 300 350

Flo

w (

m3/

sec)

In their peer review report on the Upper Peace River, Gore et al. (2002) stated,

“in general, instream flow analysts consider a loss of more than 15% habitat, as compared to undisturbed or current conditions, to be a significant impact on that population or assemblage."

15%

Low Flow Threshold - Wetted PerimeterUsed for All Blocks

Low Flow Threshold - Fish PassageUsed for All Blocks

Physical Habitat Simulation SystemUsed for Blocks 1 and 2

• Depth• Velocity• Substrate

FloodplainFloodplain

SnagsSnags

Exposed Exposed RootsRoots

Long-Term Inundation AnalysisUsed for Blocks 2 and 3

The PreliminaryResults

Flow Prescription – Percent of Flow and Seasonality (middle Peace River at Arcadia)

0

400

800

1200

1600

2000

0 50 100 150 200 250 300 350

Flo

w (

cfs)

10%

8%

13%

18%

LFT = 67 cfs

Stationary vs. Dynamic Habitat

Stationary

Dynamic - Salinity

• The volume of water in the system less than a given salinity – e.g. available fish habitat in given salinity zone

• The bottom area in the system less than a given salinity – e.g. benthic invertebrate habitat

• The shoreline length in the system less than a given salinity – e.g. amount of shoreline vegetation

Establishment of an MFL requires identification of a critical biologically-relevant variable that can be defensibly and quantitatively related to variation in freshwater flows.

Analytical Tools

“Modelers are people who like to play with numbers, but don’t have the personality to become

engineers.”

– Jimmy Carter

Allowable Percent Reduction in Flow Under: Block

Median Flow (cfs) Low Flow Condition High Flow Condition

Block 1 (April 20 – June 25) 221 10% 26% Block 2 (October 27 – April 19) 330 14% 21% Block 3 (June 26 – October 26) 1370 12% 15%

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1000

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0 100 200 300

Day of Year

Flo

w (

cfs

)

Block 1 Block 2Block 2 Block 3

LFT = 90 cfs

Based on Combined Flows of Horse, Joshua and Arcadia Gages

The Public Dialogue• MFL Priority List and Schedule – Annual Update• Proposed MFL – Report for Peer Review and Public

Dissemination• Public Meetings • Waterbody Advocates and TAC’s and NEP’s• Peer Review Report• Staff Response• (Recovery Strategy) $$$$$• Rule Development• Rule Adoption• The Role of the Governing Board

Recommendations for Others /

Lessons Learned

• Legislative mandate has greatly facilitated process

• ad valorem taxing authority of WMDs

• Peer review process

• Recovery

Peace River by P. Metz - USGS

Recovery Strategies

Questions

Photo: Richard Gant – Silver River 2007 Florida photographic collection