The Leonhardt Lagoon at Fair Park A review of current water quality and guidelines for remediation Presented by David Jones, KHA Koi & Water Garden Club of North Texas

History When Patricia Johanson first visited Fair Park Lagoon in the 1980’s, years of local lawn fertilization had washed fertilizer into the lagoon, causing algal bloom. A green slime covered the water, and there were hardly any plants or animals..

1980’s Renovation Major refurbishment 1980’s Major refurbishment 1980’s Lagoon dredged, eroding banks rebuilt Lagoon dredged, eroding banks rebuilt Concrete structures were built Concrete structures were built Restocked with native species of plants & fish Restocked with native species of plants & fish Perimeter trail became a “living exhibit” Perimeter trail became a “living exhibit” The Lagoon became a jewel in Fair Park The Lagoon became a jewel in Fair Park

Current Water Quality Issues Uncontrolled algae growth Uncontrolled algae growth Decomposing plant life is adding to bio load Decomposing plant life is adding to bio load High CO2 and Hydrogen Sulfite levels High CO2 and Hydrogen Sulfite levels Dissolved oxygen is low Dissolved oxygen is low City water additions are harmful to fish and other organisms City water additions are harmful to fish and other organisms

Green Slime Algae 8/18/06

What is The Status Quo? Algae problems are increasing Algae problems are increasing Water quality has deteriorated due to runoff and cumulative effects of many issues Water quality has deteriorated due to runoff and cumulative effects of many issues The Lagoon is now in ecological decay The Lagoon is now in ecological decay Stagnant water body with no flow and no turnover Stagnant water body with no flow and no turnover Low oxygenation levels have led to an unhealthy lake condition known as eutrophication Low oxygenation levels have led to an unhealthy lake condition known as eutrophication

What is Eutrophication? It is a condition in an aquatic ecosystem where high nutrient concentrations stimulate blooms of algae - phytoplankton. It is a condition in an aquatic ecosystem where high nutrient concentrations stimulate blooms of algae - phytoplankton. This enhanced plant growth, often called an algal bloom, reduces dissolved oxygen in the water when dead plant material decomposes and can cause other organisms to die. This enhanced plant growth, often called an algal bloom, reduces dissolved oxygen in the water when dead plant material decomposes and can cause other organisms to die. This condition creates water with a low concentration of dissolved oxygen and is not a suitable habitat for fish or other lake organisms This condition creates water with a low concentration of dissolved oxygen and is not a suitable habitat for fish or other lake organisms

The Start of Lake Decay

Eutrophic Body of Water CO2H2SO4 Anaerobic Bacteria

Algae Blooms in The Lagoon Copper Sulfate treatment used in early August to rid the Lagoon of unsightly algae blooms Copper Sulfate treatment used in early August to rid the Lagoon of unsightly algae blooms Chemical treatment destroyed the algae bloom but had detrimental effects Chemical treatment destroyed the algae bloom but had detrimental effects Dead and decaying algae and plant material will worsen the eutrophic condition Dead and decaying algae and plant material will worsen the eutrophic condition Copper Sulfate is NOT bio-degradable and may have undesirable side effects Copper Sulfate is NOT bio-degradable and may have undesirable side effects

Effects of Copper Sulfate Copper Sulfate kills algae Copper Sulfate kills algae Copper Sulfate kills plants Copper Sulfate kills plants Copper Sulfate kills fish eggs and fry Copper Sulfate kills fish eggs and fry Algae sinks to bottom and starts to decay Algae sinks to bottom and starts to decay Decaying plant materials provide nutrients for new crop of algae... it’s a vicious circle! Decaying plant materials provide nutrients for new crop of algae... it’s a vicious circle!

Copper Sulfate Sprayed 8/06

Summary of Present Conditions Large body of water with no circulation Large body of water with no circulation Runoff from surrounding areas adds nutrients Runoff from surrounding areas adds nutrients Ineffective water mixing by fountain Ineffective water mixing by fountain Algaecides have added to present condition Algaecides have added to present condition Water stratifies - warm upper and cooler deeper Water stratifies - warm upper and cooler deeper Lots of decay processes in deeper water Lots of decay processes in deeper water Very low D.O. in deeper water can’t support life Very low D.O. in deeper water can’t support life The whole water column needs remediation The whole water column needs remediation

New Water Quality Goals Introduce top to bottom circulation to water by using aeration to add oxygen to deeper water Introduce top to bottom circulation to water by using aeration to add oxygen to deeper water Add routine enzymes to dissolve decaying muck Add routine enzymes to dissolve decaying muck Use non-chlorinated water supply from Aquarium Use non-chlorinated water supply from Aquarium Replant marginal plant areas – let Nature work Replant marginal plant areas – let Nature work Water quality program to monitor progress Water quality program to monitor progress No further chemical treatments No further chemical treatments

Problem - Solution Storm water runoff/fertilizers Storm water runoff/fertilizers Recurrent Algae blooms Recurrent Algae blooms Dead plants from chemical spray Dead plants from chemical spray High level of nutrients from decaying plants High level of nutrients from decaying plants Minimal circulation Minimal circulation Low dissolved oxygen Low dissolved oxygen Water supply issue Water supply issue

Water Supply Aquarium’s well has high capacity Aquarium’s well has high capacity Previous history – used Aquarium water maintained a constant level in the Lagoon Previous history – used Aquarium water maintained a constant level in the Lagoon Transfer pipe was damaged in mid 1990’s Transfer pipe was damaged in mid 1990’s Since then, falling water level augmented by city water (chlorinated) Since then, falling water level augmented by city water (chlorinated) Aquarium wastes useable water in sewer Aquarium wastes useable water in sewer

Circulate Water With Aeration

Aeration in Action

Aeration Remediation

Action Timeline Survey the lagoon for silt buildup and bottom depth – needed to select oxygenation equipment Survey the lagoon for silt buildup and bottom depth – needed to select oxygenation equipment Choose site for air pump cabinet, plumbing, GFI wiring etc, for aeration locations in the lagoon Choose site for air pump cabinet, plumbing, GFI wiring etc, for aeration locations in the lagoon Install air pump equipment in accessible location Install air pump equipment in accessible location Add enzymes to help dissolve muck Add enzymes to help dissolve muck Establish supply from Aquarium to use “good” water which is dumped in the sewer at present Establish supply from Aquarium to use “good” water which is dumped in the sewer at present

Aeration Equipment in Box

What’s Next? Engineering drawings of Lagoon Engineering drawings of Lagoon Boat access to water for survey of lake bottom Boat access to water for survey of lake bottom Choice of equipment needed based on survey Choice of equipment needed based on survey Final agreement on plan – and CoC Final agreement on plan – and CoC Funding for equipment purchase Funding for equipment purchase Equipment installation by Park staff and me Equipment installation by Park staff and me Water supply from Aquarium established Water supply from Aquarium established Update Nature Trail Update Nature Trail

Discussion