However, the 2000 spring survey showed that the mean biomass of Egeria densa in the lake was still only 11 percent of the biomass present in the lake before treatment and five years after the whole lake Sonar treatment. Managers of reservoirs and some lake systems may have the ability to lower the water level as a method of managing aquatic plants. Goldsby and Sanders reported that consecutive drawdowns in Black Lake, Louisiana eradicated Brazilian elodea. They noted that consecutive drawdowns may be more effective than an individual drawdown. Using mechanical controls while the plant is still invading, will tend to enhance its rate of spread.
Harvesting removes surfacing mats and creates open areas of water.
Harvesting has been used extensively on Long Lake, Kitsap County to control Brazilian elodea. It is unknown what insects or pathogens have biocontrol potential for Brazilian elodea. This may have potential as a biological control agent for Brazilian elodea. Brazilian elodea is highly preferred over most native species and theoretically, it should be possible to remove Brazilian elodea while favoring the growth of native species. However, in practice, grass carp often remove the entire submersed aquatic community and should be used with great care.