1. Nutrient recycling would be reduced or eliminated from dried, compacted
sediments.
2. Suitable substrate for rooted aquatic vegetation would also be a result.
This plan to lower the lake about 7 ft below normal water level was not
implemented, however, because of the projected cost (20 million USD) and because
of concern about environmental and economic impacts [36]. For example, the loss of
lake volume would minimize the freeze protection citrus growers received from the
large heat capacity of the lake.
In the 1970s, additional studies were conducted on water quality problems and on
restoration of Lake Apopka [37]. Studies of techniques that might be used to restore
the lake have continued. Biomanipulation of algal standing crops with gizzard shad
may actually increase standing crops of undesirable algae. A multimillion-dollar
feasibility study on growing and harvesting water hyacinths to remove nutrients
from the lake was launched [38]. The field test of this project in Lake Apopka was
abandoned when the enclosure that was to have been used for the experiment was
destroyed by water movements in the lake.
The St. Johns Water Management District began a feasibility study on using
marsh restoration to improve water quality in the lake [39]. The water management
district purchased muck farmland that will be flooded to restore the wetland by using
the wetland as a filter to remove nutrients. The hydrology of the wetland will be
manipulated so that highly nutrient-enriched water will flow from the lake into the
wetland and nutrient-depleted water from the wetland will be directed back to the
lake. If successful, this project will result in both a restored wetland and a
restored lake.
There seem to be two divergent views about Lake Apopka. One group contends
that the lake can be restored. This viewpoint is supported by the need to reduce
nutrient inputs to prevent accelerated eutrophication. Schneider and Little [35]
commented that the history of Lake Apopka “is not atypical” because other lakes
in Florida and reservoirs all over the south were being subjected to similar attacks.
They stated that the lake could be restored, but only with great expense and difficult
decisions (e.g., the extent to which a 10 million USD plus marginal muck farming
operation could expend money for nutrient removal). “The technical capabilities to
prevent accelerated eutrophication are and have been available for some time. The
planning and foresight needed to prevent the early demise of our lakes, however, has
come into being only lately. Today, we must consider the full ecological impact of
all our resource development activities if we are to eliminate the Lake Apopka
syndrome from our aquatic environment,” they emphasized.
At the other extreme is the viewpoint that restoration should not be attempted
because it will meet with failure or it is too expensive. This viewpoint can be
supported to a certain extent with results of studies on Lake Tohopekaliga (Lake
Toho), Florida. A number of restoration measures have been instituted on Lake Toho
since 1971, with little evidence of improvement in water quality [39]. In this lake,
nutrient inputs have been reduced by sewage treatment and by stormwater detention
and filtration. In addition, drawdown has been used as a restoration measure. What is
7 Lake Restoration
303
sediments.
2. Suitable substrate for rooted aquatic vegetation would also be a result.
This plan to lower the lake about 7 ft below normal water level was not
implemented, however, because of the projected cost (20 million USD) and because
of concern about environmental and economic impacts [36]. For example, the loss of
lake volume would minimize the freeze protection citrus growers received from the
large heat capacity of the lake.
In the 1970s, additional studies were conducted on water quality problems and on
restoration of Lake Apopka [37]. Studies of techniques that might be used to restore
the lake have continued. Biomanipulation of algal standing crops with gizzard shad
may actually increase standing crops of undesirable algae. A multimillion-dollar
feasibility study on growing and harvesting water hyacinths to remove nutrients
from the lake was launched [38]. The field test of this project in Lake Apopka was
abandoned when the enclosure that was to have been used for the experiment was
destroyed by water movements in the lake.
The St. Johns Water Management District began a feasibility study on using
marsh restoration to improve water quality in the lake [39]. The water management
district purchased muck farmland that will be flooded to restore the wetland by using
the wetland as a filter to remove nutrients. The hydrology of the wetland will be
manipulated so that highly nutrient-enriched water will flow from the lake into the
wetland and nutrient-depleted water from the wetland will be directed back to the
lake. If successful, this project will result in both a restored wetland and a
restored lake.
There seem to be two divergent views about Lake Apopka. One group contends
that the lake can be restored. This viewpoint is supported by the need to reduce
nutrient inputs to prevent accelerated eutrophication. Schneider and Little [35]
commented that the history of Lake Apopka “is not atypical” because other lakes
in Florida and reservoirs all over the south were being subjected to similar attacks.
They stated that the lake could be restored, but only with great expense and difficult
decisions (e.g., the extent to which a 10 million USD plus marginal muck farming
operation could expend money for nutrient removal). “The technical capabilities to
prevent accelerated eutrophication are and have been available for some time. The
planning and foresight needed to prevent the early demise of our lakes, however, has
come into being only lately. Today, we must consider the full ecological impact of
all our resource development activities if we are to eliminate the Lake Apopka
syndrome from our aquatic environment,” they emphasized.
At the other extreme is the viewpoint that restoration should not be attempted
because it will meet with failure or it is too expensive. This viewpoint can be
supported to a certain extent with results of studies on Lake Tohopekaliga (Lake
Toho), Florida. A number of restoration measures have been instituted on Lake Toho
since 1971, with little evidence of improvement in water quality [39]. In this lake,
nutrient inputs have been reduced by sewage treatment and by stormwater detention
and filtration. In addition, drawdown has been used as a restoration measure. What is
7 Lake Restoration
303