|
* Update on Hydrilla *
Hydrilla is the non-native, invasive, vine-like plant that has established a strong presence in the Swift Creek Reservoir (SCR). First observed in 2009 at the northwest end of SCR, it now grows out from most of the shoreline of the reservoir. In 2021, the growth of hydrilla was very strong (three times as dense as in 2020).
In SCR, hydrilla has crowded out most native aquatic plants and it impedes many recreational uses and it can create an unappealing appearance when it grows to the surface of the water.
Total elimination of hydrilla is not an option. Reservoirs and lakes need some native vegetation in order to remain “healthy.” Without vegetation, large “blooms” of algae can occur and the habitat for fish, etc., is destroyed. The algae makes water processing more difficult and it can be toxic, unsightly, and smelly.
The Chesterfield Utilities Department, which “owns” the water in SCR, has taken on the responsibility of providing the “primary” control of hydrilla. This is done by adding large numbers of “vegetarian” grass carp to SCR. The carp eat the hydrilla. Because of variations in water temperature, sunlight, precipitation, etc., estimating the right number of carp to add each year is difficult. Thus, we can expect variations from year to year in the amount of hydrilla in SCR.
“Secondary” controls of hydrilla (such as mechanical “mowing”) to improve recreational uses of SCR and improve its appearance are left to residents and Home Owner Associations.
In 2010, a team called the Reservoir Hydrilla Management Group (RHMG) was formed to address the hydrilla issue. The RHMG is made up of co-chairpersons from the Utilities Department, Woodlake, Brandermill, and “at-large" representatives of other concerned parties.
The RHMG holds annual public meetings to report results and plans related to hydrilla control. The 2022 meeting was held last Tuesday, March 15.
The major conclusions reported at the meeting were:
- There was exceptional growth of hydrilla in 2021
- It is believed that large quantities of hydrilla-eating carp were washed over the dam during the major floods of 2018 and 2020, enabling the dense growth seen in 2021
- 3500 carp will be added to the lake in April (the largest addition since 2010).
- These 1 -2-pound carp are expected to have a moderate impact in 2022 and a much stronger impact in 2023 as their appetites increase.
- Secondary controls are under active review by the RHMG.
Comprehensive meeting notes and a link to the County Powerpoint presentation can be found HERE.
| 
