Hydrologic Restoration of the Taylor Slough Region of Everglades National Park

Hydrologic Restoration of the Taylor Slough Region of Everglades National Park. Changes in Water Quality and Implications for Ecosystem Restoration

Paul Julian University of Florida Department of Soil and Water Science Acknowledgements • UF Water Institute • Department of Soil and Water Science • Wetland Biogeochemistry Lab • Dr Alan Wright (UF) • Dr Todd Osborne (UF) • Dr Garth Redfield (SFWMD) • Dr Donatto Surratt (NPS-ENP)

And Viewers like you!! Where in the world is Taylor Slough…

• Southern most extent of Florida. • Southeastern portion of Everglades National Park (ENP). • 2nd largest natural drainage in ENP. • Slight topographic depression.

(Sullivan et al 2014) 1994 1999 2007 2014

L31W

Pre 1994 2000-2010 • L-31W canal was constructed (1961 -1968). • Continued operation of the S-332D pump • L-31W canal operated for water supply to station and detention area. Taylor Slough via gravity flow (1969-1980). • Operation of the S-332B and S-332C and pump • S-332 pump stations installed South-Dade stations and detention areas (further north). Conveyance System operation commenced • Construction and operation of the Frog Pond (1981-1991). detention area. 1992 – 1999 • Construction and operation of the C-111 • S-332 pump station capacity was increased from Western Features (Comprehensive Everglades 4.7 m3 s-1(~160 cfs) to 14.2 m3 s-1 (~500cfs). Restoration Plan) located further south. • S-332D pump station and detention area commenced operation (1999). Everglades Water Quality and Quantity

Water Quality Water Quantity • Historically low-nutrient • Historically a system (i.e. oligotrophic). hydrologically connected system. • Phosphorus (P) limited system. • Compartmentalization and fragmentation altered • Due to stormwater run-off the Quantity, Time and some areas have become Distribution. eutrophic.

• High nutrients=altered ecosystem composition. Eutrophication Metric Soil

Peat Marl • Within the Everglades >500 mg/kg TP indicate enrichment. • More applicable to peat-based soils. • Developed using data from the Water Conservation Areas. • May not reflect eutrophication in hydrologically isolated depositional (solution holes) areas.

Scheidt D, Kalla PI (2007) Everglades ecosystem assessment: water management and quality, eutrophication, mercury contamination, soil and habitat: monitoring for adapyive management: a R-EMAP status report. United States Environmental Protection Agency, Athens, GA Eutrophication Metric Vegetation plants.ifas.ufl.edu

• Cattails (Typa spp.) are used as indicator species of eutrophication and disturbance. • Respond to changes in water quality. • Also respond to changes in hydrology.

Chen H, Mendelssohn IA, Lorenzen B, et al (2005) Growth and nutrient responses of Eloecharis cellulosa (Cyperaceae) to phosphate level and redox intensity. American Journal of Botany 92:1457–1466. Sklar F, Dreschel T, Warren K (2011) Ecology of the Everglades Protection Area. 2011 South Fla. Environ. Rep. Methods • Water Quality, flow, rainfall and stage data were retrieved from the South Florida Water Management District online database (DBHydro).

• Time Period May 1, 1985 to April 30, 2013 (WY1986-2013).

• Qualified data was screened.

• WQ data reported less than the MDL was set to the reported MDL.

• Statistical analysis was performed in R. Results: Hydrology

• Rainfall: No significant annual trend ( = 0.13, =0.34).

• Inflow (S332): Significant annual trend ( = 0.50, <0.01, Sen Slope=0.98 x 107 m3 yr-1).

• Outflow (TSB): Significant annual trend ( = 0.32, <0.05 , Sen Slope=0.24 x 107 m3 yr-1).

*Sen slope analysis performed using the “zyp” R package. Results: Hydrology

Piecewise regression

• R2=0.99, t-value=6.53, DF=22, <0.01 • Identified 1991 and 2000 as breaks. • Correspond to changes in water management.

• R2=0.99, t-value=4.96, DF=22, <0.01 • Identified 1992 and 2009 as breaks. • Delayed response to changes up-stream. • 2nd change due to the C-111 CERP project and Frog Pond Detention Area.

*Piecewise regression performed using the “segmented” R package. Surface Water Inflow Period Sheet-flow/Groundwater Period

1986 - 2002

Kotun K, Renshaw A (2014) Taylor Slough Hydrology: Fifty Years of Water Management 1961 - 2010. Wetlands 34:9–22. Surface Water Inflow Period Sheet-flow/Groundwater Period

1986 - 2002 2002 - Present

Kotun K, Renshaw A (2014) Taylor Slough Hydrology: Fifty Years of Water Management 1961 - 2010. Wetlands 34:9–22. Results: Water Quality (Phosphorus)

Flow-weighted Mean Concentration

Surface-water inflow period. • Significantly decreasing annual trend. •  = -0.42, <0.05, Sen Slope=-0.2 g L-1 yr-1

• Significantly decreasing annual trend. •  = -0.76, <0.01, Sen Slope=-0.1 g L-1 yr-1 Concentration-Loading Curve 101

Okay, here we go, short, short version! Piece Three • No more P being removed (i.e. reached its assimilation capacity).

Piece One • Any added P is contained (i.e. assimilated). • Background concentration (i.e. C*).

Kadlec RH (1999) The limits of phosphorus removal in wetlands. Wetlands Ecology and Management 7:165–175. Results: Concentration-Loading Curve

• Significant Log-Log Relationship (R2 0.34, F ratio 6.57, <0.05) with a slight decrease in FWM as PLR approaches 1.0 g/m2/yr. • Doesn’t follow the characteristic “one-gram rule” of a typical concentration- loading curve. • Exceeds the 1.0 g/m2/yr CERP restoration target. • Could indicate: 1. Different P-removal processes (i.e. Ca-P interactions), 2. Upper Taylor Slough hasn’t been loaded sufficiently to elicit a response. Cattail Observations

• Studies have suggested cattail expansion in the Upper Taylor Slough Region (Sadle 2008; Surratt et al 2012).

Annual FWM (g/L) Aerial Imagery Year S332 TSB Coverage 1994 No cattail detected 9.9 5.5 1999 No cattail detected 7.0 5.0 2004 ~ 8.1 ha 5.8* 4.2 2007 ~ 5.7 ha (field data) 5.4* 3.8 2009 ~ 7.9 ha 6.3* 3.1 * Surrogate S332D

• Surratt D, Shinde D, Aumen N (2012) Recent Cattail Expansion and Possible Relationships to Water Management: Changes in Upper Taylor Slough (Everglades National Park, Florida, USA). Environmental Management 49:720–733. • Sadle J (2008) Summary of cattail encroachment in Taylor Slough. South Florida Natural Resource Center, Homestead, FL Natural Enrichment Process…possible explanations of cattail occurrence and persistence.

Osborne TZ, Ellis LR (2015) Monitoring of Phosphorus Storage in Park Marsh Land Sediments: An assessment of the C-111 Spreader Canal Project. National Park Service, Everglades National Park Natural Enrichment Process…possible explanations of cattail occurrence and persistence. Total Phosphorus Inorganic Phosphorus

• Restoration efforts are still on-going.

• Changing from a direct surface-water inflow to groundwater/sheet-flow inflows has resulted in hydrologic improvements.

• Very low (ultra-oligotrophic) Total Phosphorus concentrations have been observed within Upper Taylor Slough.

• These low concentrations are hard to reconcile with assertions of region- wide enrichment.

• A natural enrichment processe of in-situ P recycling due to the combination of micro-topography, geology and hydrology in concert with a biotic accumulation cycle could facilitate cattail growth and expansion. Questions?

Thank You