Download Retention Ponds - Hillsborough County Extension Office

03/26/2013
Retention Ponds
Florida-Friendly Landscaping™
Hillsborough County Extension
University of Florida, IFAS
Retention Ponds – Quick Facts
 Legislation was enacted in the 1980’s, which
required treatment of stormwater
 Most were built within the past 20 years
 Largest number in Florida
 Commonly referred to as “lakes”
Image source: Winnipeg.ca.
Retention vs. Detention Ponds
 Retention ponds are designed to RETAIN
water.
– Permanent pool of water
– Water level fluctuates in response to precipitation
and runoff from the contributing areas.
Watersheds
 It’s All Connected - Even
Retention vs. Detention Ponds
 Retention ponds are designed to RETAIN
water.
 Detention ponds are designed to DETAIN
water.
– Slows down water flow
– Holds stormwater for a short period of time
– Usually dry, except for during or after rain
Stormwater Ponds
Water after a storm or heavy rain event either:
if you don’t live on the waterfront,
your land is still directly connected
to a nearby waterbody.
 Percolates (i.e. sinks into) through soil, recharging
groundwater (or the aquifer) directly
 Like a Bowl -
A Watershed
is the area of land where all of the
water that is under it or drains off of
it goes into the same place.
 Aquifer Connection
– All
watersheds are connected to the
underground aquifer, which
supplies most of Florida’s drinking
water.
Image source: Marmaton Wraps.
Original image source: FAO – United Nations.
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Stormwater Ponds
Water after a storm or heavy rain event either:
 Percolates (i.e. sinks into) through soil, recharging
groundwater (or the aquifer) directly OR
 Runs off of impervious surfaces, where excess water
is collected in the retention pond
Stormwater Management Systems
 Prevents flooding by
detaining stormwater after
a storm event
 Improves water quality by
providing a natural filter for
pollutants
 Wildlife habitat
 Recreational activities and
a neighborhood amenity
Original image source: FAO – United Nations.
Pond Maintenance - Now What?
 Turned over to communities to maintain
 Responsibility applies to all homeowners
 Ignorance of the importance of pond
maintenance
 Affects pond lifespan, future maintenance
costs and property values
 Communities and environment downstream
Lake or Pond Eutrophication
Image source: University of Florida.
Retention Ponds – Sad Reality
 In the process of dying
 Will have to be re-dredged
 Lifespan: 20 – 25 years
Eutrophication Affects:
 Algae
 Quantity and type of aquatic
plants
 Water quality
 Water clarity and depth
 Fish populations
 Note: Sometimes Beneficial
 Process of nutrient
enrichment of lakes
– Nitrogen and Phosphorus stimulate
the growth of aquatic plants,
including algae.
 Caused by natural and
human factors
– Wastewater disposal
– Agricultural practices
– Urban run-off (From yards, golf
courses, shopping centers and
roads)
 Repercussions downstream
– Flooding
– Pollution discharge
Image source: University of Florida.
Original image source: University of Florida.
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Pollution
 Point Source
– Readily identified source
– Contribution greatly lessoned, due to
environmental regulations
 Non-Point Source
– Not easily traced to source
Pollution Sources – Urban Settings
Construction activities
Degrading roads/pavement
Emissions from motor vehicles
Vegetation, which as leaves,
grass and other yard debris
 Litter and trash, including pet
wastes
 Chemicals
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– Fertilizers
– Pesticides
– Herbicides
 Wastewater, including overflow
from septic systems
Algae
 Single celled, almost
microscopic organism
 Live in large colonies
 Not exactly a terrestrial plant –
No roots, stems or leaves
 Performs photosynthesis
 Similar growth requirements as
plants
– Nutrients
– Light
 30,000 species
“Good” Algae - Chara
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Attaches to pond sediments
Found 2 – 3’ below surface
Indicator of clear water
Forms mats when free-floating
Helpful to stormwater systems
Take care not to kill off
Phosphorus is key:
– In waters with low levels of P
(< 20 micrograms/L)
– Filamentous green algae requires
high P levels
“Good” vs. “Bad” Algae
 4 Types
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Cyanobacteria – blue-green
Chrlorophyta – green
Phaephyta – brown
Rhodophyta - red
 “Good” algae
– Includes many types of green algae
– Indicates a healthy water system
 “Bad” algae
– Includes red, brown and blue-green
varieties
– System is out of balance
Stormwater Pond
Best Management Practices (BMP’s)
 General definition: Methods or techniques found to be the most
effective and practical means in achieving an object (such as
preventing or minimizing pollution) while making the optimum use of
available resources.
 In terms of stormwater management: Both structural or engineered
control devices and systems (e.g. retention ponds) to treat polluted
stormwater, as well as operational or procedural practice (e.g.
minimizing use of chemical fertilizers and pesticides).
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Stormwater Pond
Best Management Practices (BMP’s)
Keep inflow and outflow structures clear
Weed control, including invasive vegetation
Shoreline stabilization
Pollution prevention - Keep anything other than
water from entering the stormwater system
 Establish a maintenance-free buffer zone
 Dredging and repair
 Monitoring
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BMP’s – Public Acceptance is Key
 Come to consensus
– Serves/benefits all members of a community
– Can adversely affect all
 Prioritize intended uses for ponds
– Top priorities – flood prevention and pollution control
– Other uses – irrigation, recreation and marketability
 Create community-wide awareness of the program
 Explain how individuals can help implement the plan
 Monitor the program and obtain feedback
BMP’s – Dredging
 Definition: To remove sand, silt, mud,
muck, etc. from the bottom of a stormwater
pond or other waterbody.
Stormwater Pond
Restoration Treatments
(Buying time before re-dredging)
 Aeration
BMP’s – Dredging
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Inevitable
Expensive
Long and complicated permitting process
Harmful to fish and wildlife
Dredged “muck” is harmful to environment
Stormwater Pond
Restoration Treatments
 Aeration
 Floating Wetland
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Stormwater Pond
Restoration Treatments
 Aeration
 Floating Wetland
 Grass Carp
Stormwater Pond
Restoration Treatments
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Stormwater Pond
Restoration Treatments
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Aeration
Floating Wetland
Grass Carp
Copper Sulfate
Dye
Restoration Treatments - Aeration
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Restoration Treatments –
Floating Wetland
 Plastic grid filled with native aquatic plants and
anchored in place within the pond
 Competes with algae for pond nutrients
 Harvesting of plants, necessary to remove
accumulated nutrients
 Aesthetically pleasing
 Effective
Aeration
Floating Wetland
Grass Carp
Copper Sulfate
Oxygenates water
Mixes water to prevent stratification
Controls accumulation of pond bottom muck
Can add 20 – 25 years to life of pond
Fountain ≠ Aeration
Should be run 24 hours a day
Most effective treatment method
High cost
Restoration Treatments –
Grass Carp
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Biological control – herbivorous fish
Sterile – live 10 years
“Grazer” – feeds on surface and shallow water plants
Not effective in controlling “bad” algae
Prefers Hydrilla and Chara
Effective on certain types of nuisance plants
Low cost
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Restoration Treatments –
Copper Sulfate
 pH of water needs to be measured prior to
treatment
 Can cause Oxygen concentrations to drop
 Can cause fish kills
 Linked to methylmercury
 Short-term - Can be effective
 Long-term - Starts a negative self-feeding cycle
 Relatively inexpensive
 Not recommended for low alkalinity or low oxygen
ponds
Key to Pond Maintenance –
Control What Enters the Pond
 Proper disposal of trash and waste
Key to Pond Maintenance –
Control What Enters the Pond
 Proper disposal of trash and waste
 Appropriate use of pesticides, herbicides and
fertilizers
 Apply fertilizer only when grass is actively
growing
Restoration Treatments - Dyes
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Darkens the water
Reduces sunlight penetration
Limits plant growth
Safe for aquatic wildlife
Spreads readily
Effective
Inexpensive
Key to Pond Maintenance –
Control What Enters the Pond
 Proper disposal of trash and waste
 Appropriate use of pesticides, herbicides and
fertilizers
Key to Pond Maintenance –
Control What Enters the Pond
 Proper disposal of trash and waste
 Appropriate use of pesticides, herbicides and
fertilizers
 Apply fertilizer only when grass is actively
growing
 Use fertilizer formulations that are at least
50% slow release
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Key to Pond Maintenance –
Control What Enters the Pond
 Proper disposal of trash and waste
 Appropriate use of pesticides, herbicides and
fertilizers
 Apply fertilizer only when grass is actively
growing
 Use fertilizer formulations that are at least
50% slow release
 Enforce municipal “illegal dumping”
ordinances
Key to Pond Maintenance –
Control What Enters the Pond
 Proper disposal of trash and waste
 Appropriate use of pesticides, herbicides and
fertilizers
 Apply fertilizer only when grass is actively
growing
 Use fertilizer formulations that are at least
50% slow release
 Enforce municipal “illegal dumping”
ordinances
 Post “No littering” signs that include a phone
number
 Periodic street sweeping
Buffer Zone Considerations
 Never grow grass to the edge of pond (or stormwater
drain)
 Don’t mow, fertilize or apply pesticides
 Don’t apply irrigation (after plants are established)
 Avoid loose grass clippings
 Prevent pet wastes from reaching water body
Key to Pond Maintenance –
Control What Enters the Pond
 Proper disposal of trash and waste
 Appropriate use of pesticides, herbicides and
fertilizers
 Apply fertilizer only when grass is actively
growing
 Use fertilizer formulations that are at least
50% slow release
 Enforce municipal “illegal dumping”
ordinances
 Post “No littering” signs that include a phone
number
Maintenance-Free Zone
 Create a low maintenance buffer zone
– At least 10 feet wide
– Can include low maintenance plants
– Remove invasive species
 Purpose
– Natural filter
– Attracts wildlife
– Prevents erosion
Aquascaping
 Practice of using aquatic and wetland plants
to landscape in and around water.
 Many counties in Florida promote and
require Aquascaping of stormwater ponds.
 Maintenance – Aquascaping, like gardening
and landscaping, must be maintained.
Image source: Orange County, FL.
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Aquascaping - Purpose
Aquascaping
Pollutant filtration
Erosion control
Wildlife habitat
Invasive plant species
control
 Aesthetic value
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Image source: University of Florida.
Aquascaping – Plants
 Submersed
– grow entirely under water
– cannot survive out of water.
 Bacopa caroliniana, Lemon Bacopa
Aquascaping – Plants
 Floating
– float free on the water
– rooted in the ground with leaves floating on the surface
 Nelumbo lutea, American Lotus
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Determine average water level on a yearly basis
Measure maximum depth in the planting areas
Start in deepest zone and work toward shore
Marginal and transitional plants in buffer zone
Aquascaping – Plants
 Submersed
– grow entirely under water and
– cannot survive out of water.
 Ludwigia repens, Red Ludwigia
Aquascaping – Plants
 Floating
– float free on the water
– rooted in the ground with leaves floating on the surface
 Nymphaea odorata, Fragrant Waterlily
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Aquascaping – Plants
 Emergent - rooted in the ground
– Aquatic plants
 need to be rooted in the water
 leaves and flowers project above the water
Aquascaping – Emergent Plants
 Aquatic
– need to be rooted in the water
– leaves and flowers project above the water
 Iris virginica, Blue Flag Iris
– Canna flaccid, Golden Canna
Aquascaping – Emergent Plants
 Aquatic
– need to be rooted in the water
– leaves and flowers project above the water
 Pontederia cordata, Pickerelweed
Aquascaping – Emergent Plants
 Aquatic
 Short-stemmed marginal plants
– low growing bog-type plants that grow
well on wet mud or sand
 Drosera cappillaris, Pink Sundew
Aquascaping – Emergent Plants
 Aquatic
– need to be rooted in the water
– leaves and flowers project above the water
 Sagittaria lancifolia, Duck Potato
Aquascaping – Emergent Plants
 Aquatic
 Short-stemmed marginal plants
– low growing bog-type plants that grow
well on wet mud or sand
 Eriocaulon spp., Pipeworts
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Aquascaping – Emergent Plants
 Aquatic
 Short-stemmed marginal plants
 Marginal or transitional plants
Aquascaping – Emergent Plants
 Aquatic
 Short-stemmed marginal plants
 Marginal or transitional plants
– grow on the interface of wetland and
upland habitats
– prefer changing water levels
– grow on the interface of wetland and
upland habitats
– prefer changing water levels
 Helianthus angustifolius, Swamp Sunflower
 Cephalanthus occidentalis, Buttonbush
Aquascaping – Emergent Plants
Aquascaping – Emergent Plants
 Aquatic
 Aquatic
 Short-stemmed marginal plants
 Marginal or transitional plants
 Short-stemmed marginal plants
 Marginal or transitional plants
– grow on the interface of wetland and
upland habitats
– prefer changing water levels
– grow on the interface of wetland and
upland habitats
– prefer changing water levels
 Muhlenbergia capillaris, Gulf Muhly Grass
Aquascaping – Emergent Plants
 Aquatic
 Short-stemmed marginal plants
 Marginal or transitional plants
– grow on the interface of wetland and
upland habitats
– prefer changing water levels
 Taxodium distichum, Bald Cypress
 Zephyranthes atamasco, Rain Lily
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Retention Ponds
In the process of dying
Will have to be re-dredged
Lifespan: 20 – 25 years
Buy time by:
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Aeration system
Do not grow grass up to water’s edge
Establish maintenance-free zone
Prevent pollutants from entering
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Resources
Resources (cont.)
Adopt-A-Pond Program, Hillsborough County –
http://www.hillsborough.wateratlas.usf.edu/AAP/
IslandWalk Community DVD – Dr. Herb Schuchman, Co-chair, Lake
Committee – email: [email protected]
Center for Aquatic and Invasive Plants, University of Florida Institute of
Food and Agricultural Sciences – http://plants.ifas.ufl.edu/
Stormwater Systems in Your Neighborhood brochure – Southwest Florida
Water Management District http://www.swfwmd.state.fl.us/publications/type/all
Clemson Cooperative Extension –
http://www.clemson.edu/extension/natural_resources/water/stormwater_pon
ds/
The Florida-Friendly Landscaping Guide to Plant Selection and Landscape
Design – Southwest Florida Water Management District –
http://www.swfwmd.state.fl.us/publications/type/all
The Florida Yards & Neighborhoods Handbook – Florida-Friendly
Landscaping™ – http://fyn.ifas.ufl.edu/publications.htm
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