How Everglades Restoration Can Mitigate Some

Effects of Sea Level Rise in South Florida

By the Arthur R Marshall 2013 Interns: Sarah Denisen, Casey Hickcox, Jessica

James, Tomena Scholze, and Kelsie Timpe

Climate Change and Sea Level Rise

Fig 1: NOAA, Climate.gov

Pre 1870s: 180-280 ppm

May 9, 2013: Mauna Loa above 400 ppm

Fig 2: IPCC 2007

Climate Change and Sea Level Rise

Fig 3: NOAA 2012

• The US National Climate Assessment predicts with high confidence that the sea will rise at least 0.2 m (8 inches) and no more than 2 m (6.6 ft) by 2100 (NOAA 2012).

Climate Change and Sea Level Rise

Table 1: NOAA 2012

Sea Level Rise: The Future of Florida

History of Everglades Restoration

Historic Flow Current Flow CERP Future Plan Flow

Threats to the urban environment• Saltwater Intrusion• Increased flooding• Infrastructure damage

Threats to the natural environment• Storm Surge• Saltwater Inundation• Mangrove Destruction• Habitat Conversion• Trophic Disruption

Outline of Sea Level Rise Threats

Threats to the Natural Environment: Storm Surge

http://www.disaster.qld.gov.au/getready/images/storm-surge.png

Physical Erosiono Sediment removalo Mangrove

destruction and removal

o Soil subsidence

Chemical Erosiono Saltwater inundation

Wetland Destructiono Almost 3100 acres in

S.Fla due to Hurricane Wilma

Healthy Ecosystems Provide Natural Protection

Mangroves - 'Natural wall'o Create peat dam o Increases drag on water

motiono Absorbs wave energyo Decreases fetch in wave

action

Inland plants o Prevent creation of waveso Increases drag on water

motiono Holds sediment in place

Peat decomposition

o Oxidative destruction

Nutrient Enrichment

o Phosphorus

Salinity increase

Threats to the Natural Environment: Saltwater Inundation

Seawater Okeechobee Everglades Goal

Mangrove Threatso Soil Erosiono Too fine sedimento Hypersalinity

Migration Capacity Limitedo SLR <9 cm/yr - Acceptableo SLR 9-12 cm/yr - Stressedo SLR >12 cm/yr - Threatened

Threats to the Natural Environment: Mangrove Destruction

• Salinity increases and reduced freshwater

-> vegetation community shiftso aquatic vegetation regime shiftso tidal marsh shifts and submergenceo buttonwood/coastal hammock loss

• Differing rates of migration -> elimination of some habitats

Threats to the Natural Environment:

Habitat Conversion

Salinity-induced vegetation shifts reduce ecosystem values

Total Ecosystem Valuation

(TEV)

Total Ecosystem Value (TEV) Decreases as Habitats Shift

• TEV decreases to $5 billion with 5 ft. of SLR

• Losses occur as ecosystems degrade to less valuable habitats through salinity changes

• C sequestration values decreased from $32 million to $490 k due to mangrove loss

• TEV is $74 billion with no SLR effects in study area

• Biological effects of physical changes caused by SLR and flow alterations o disrupted trophic interactionso productivity effectso population/community structure

changes

• Examples:o coastal fish nurserieso wading bird nesting/feeding o periphyton composition

Threats to the Natural Environment:

Trophic Disruption

The Urban Side• 2010 population along the lower east coast was

approx. 5.6 million

• 2010 gross water demand of 1,775,000,000 gallons per day

• 2030 population projected to increase by 18% to approx. 6.6 million

• 2030 gross water demand for all uses is projected to increase by 213 million gallons per day (12%)

Climate Change Threatens Water Supply

• Warming will change in the rate of evapotranspiration

• Unpredictable weather patterns and rising temperatures may increase water demands

• Less frequent but more intense rainfall, with longer dry periods in between, may increase total annual rainfall but decrease total useable rainfall - more water may be lost to tide or runoff.

• This scenario increases the necessity for long term water storage for use during dry periods.

Salt Water Intrusion Threatens Water Supply

• The majority of public water supply is pumped from shallow wells

• Salt water contaminates shallow well fields, making them unusable

• Many coastal well fields are already experiencing salt water intrusion and must be abandoned

• Utilities at risk - Lake Worth, Lantana, Hillsboro Beach, Dania Beach, Hallendale Beach, Miami-Dade south wellfields, Florida City, Homestead, and the Florida Keys Aqueduct Authority.

The Aquifer Systems under South Florida

• Surficial Aquifer System (SAS)

• Floridan Aquifer System (FAS)

• SAS holds freshwater from surface level to about 200 ft in depth

• FAS holds brackish water in several layers

Photo Credit: SFWMD

How Saltwater Intrusion Works

• When water is withdrawn faster than it is recharged, seawater moves in

• With SLR, pressure from the a growing ocean will push more saltwater inland.

Photo Credit: USGS

Connection between Water Supply and the Greater Everglades

Water from Lake Okeechobee, the Water Catchment Areas (WCAs) and the C&SF Canals recharge the SAS and Biscayne

Aquifer

Photo Credit: SFWMD Photo Credit: SFWMD

How can we meet future water supply demand?

• Diversify our water sources

• Increase surface water storage

• Use reclaimed water and rain for non-potable uses

• Increase water conservation

• Restore the Everglades Photo Credit Ken Kaye

Alternative Water Supply Options

• Temporary fix - move Biscayne and surficial aquifer system (SAS) wells inland.

• Desalinize brackish water from the Floridan Aquifer System (FAS).

• Desalinize saltwater from the ocean.

SAS and the Biscayne Aquifer

• Salt water intrusion necessitates abandoning wells or moving them further inland.

• Moving wells is costly - Earl King, assistant director of utilities for the City of Hallendale Beach, estimates moving a small wellfield inland will cost $8,500,000.

• Only a temporary fix.

• Relying exclusively on the SAS and the Biscayne is not a viable option to meet future water demand.

• Other water sources must be explored.

Floridan Aquifer System - FAS

• FAS is brackish – requires treatment (RO)

• Construction is costly.

• RO highly energy intensive. • Deep injection wells (DIWs) are

necessary

Seawater Desalinization• Unlimited, drought-proof source of water

• RO is highly energy intensive and expensive

• Brine byproduct of RO can be damaging to marine ecosystems.

• Advances technology reducing cost

• Co-location of desal facilities and coastal power plants

Ten SAS Wells & One 20 mgd

Treatment Plant

Ten FAS Wells, Two DIWs, & One 20

mgd RO Treatment plant

One Seawater 20 mgd RO Treatment Plant & Two DIWs

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100000000

120000000

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Cost Comparison of Urban Water Supply Options for the Lower East Coast

Capital Costs Annual Maintnence and Operation Costs

20

13

US

D

*These costs do not include land, water mains, or pumps .

FAS

DESAL

SAS

Supplemental Sources and Conservation Measures

Rainwater harvesting, use of reclaimed water and water conservation practices will help reduce water supply demands

Photo Credit: EPA

Reclaimed Water• Used for irrigation, agricultural

and industrial uses• Reduces pumping from

groundwater• Reduces quantity of

wastewater disposed of via ocean outfalls and deep injection wells

• Reduces need for fertilizer• Wastewater flows predicted to

increase from 636 MGD in 2010 to 832 MDG by 2030

• Is no more dirty than ocean water!

Photo Credit: SunSentinel

Rainwater Harvesting

• Inexpensive• Reduces stress on water supplies• Reduces stormwater runoff,

pollution and flooding

Photo Credit: EcoFriend Photo Credit: SunSentinal

• Help recharge the shallow Biscayne Aquifer

• Provide more surface water storage

• Prevent peat degradation

• Push back saltwater intrusion

• Reduce nutrient enrichment

• Maintain freshwater habitats for plants and wildlife.

• Maintain the coastal mangrove storm barriers

The Solution: Everglades Restoration

More water in the Everglades ecosystem will:

THANK YOU!Questions?