Lake Report

RA’s Management Philosophy

Aquatic plant invasions can sometimes be beautiful but are sometimes unsightly and can affect boat navigation. Managing plant invasions can also be costly.

Reston Association manages our lakes for multiple benefits and it is a delicate balance between ecological health, aesthetics and recreation, and the management actions required for each. We do not manage the lakes for swimming, as this activity is not permitted. We evaluate control methods of aquatic plants and algae from both a budget and ecological impact standpoint.

Water Quality Report

Reston’s lake water quality is monitored monthly during the summer season.

The latest water quality report discusses the results of the environmental monitoring program conducted from April through September for lakes Anne, Thoreau, Audubon and Newport. The Reston Association has been monitoring water quality in the lakes since 1981.

Lake Newport was added to the monitoring program in 1992. Two additional water bodies were added to the monitoring program in 2003 – Bright and Butler Ponds. The lake monitoring has been conducted by Aquatic Environment Consultants, Inc., following procedures established in previous years to ensure the data collection was compatible with previous data. By using similar methods and comparing data, long-term trends can be studied in the water quality of the lakes.

Plants of Concern in Reston

Each lake is unique in its plant communities and infestations. At each lake, RA staff monitor and manage for Purple Loosestrife (see information below).

Lake Newport

In addition to stocking grass carp, RA treated Lake Newport for bladderwort in spring 2016 and dredged to remove 5000 cubic yards of sediment in February 2017.

White Water Lily, Nymphaea odorata, is a perennial plant that often forms dense colonies. The leaves arise on flexible stalks from large thick rhizomes that grow in mucky or silty bottom sediments up to 5 feet deep. The leaves are round, bright green, 6 to 12 inches in diameter with a slit about 1/3 the length of the leaf. Leaves usually float on the water’s surface. Flowers arise on separate stalks and have brilliant white petals with yellow centers. The white water lily can spread from seeds or rhizomes.

Lake Thoreau

Lake Thoreau plants include Northern Water Milfoil, Fanwort, Hydrilla, Alligator Weed and native plants Chara, and Variable-leaf Pondweed. Fanwort was treated in June 2017. Lake Thoreau dredging began in May 2018 which increased turbidity. Water clarity normally takes a month to go back to normal post-dredging.

Fanwort, Cabomba caroliniana is a rooted, mostly submerged aquatic plant with multi-branched leaves. Small elliptical floating leaves are associated with flowering. Fanwort is capable of rapidly spreading on its own by stem fragments or rhizomes. It creates large floating mats of vegetation which obstruct water traffic and prevent light penetration for growth of native plants.

Alligator weed, a plant native to South America, forms dense mats that crowd out native species and impede recreational activities such as boating and fishing. Alligator weed was found growing along the dam and shoreline areas near Lakewinds Drive.

Lake Audubon

RA treats Lake Audubon monthly for blue-green algae in the summer, following monitoring by a third-party consultant. Lake Audubon has few nuisance plant concerns, though Water Lettuce (Pistia stratiotes) has been seen once on this lake. This is an easily removed but potentially prolific invader.

Lake Anne

RA treats Lake Anne monthly for blue-green algae control in the summer. Be on the lookout…Water primrose is becoming a regular plant found at Lake Anne. RA members are encouraged to remove it from shoreline areas by hand pulling.

Water primrose is a perennial plant that grows along the shoreline and can form long runners out across the water surface. It produces yellow flowers and can regrow from seeds and any remaining roots.

Water Quality Report

Reston’s lake water quality is monitored monthly during the summer season.

The latest water quality report discusses the results of the environmental monitoring program conducted from April through September for lakes Anne, Thoreau, Audubon and Newport. The Reston Association has been monitoring water quality in the lakes since 1981.

Lake Newport was added to the monitoring program in 1992. Two additional water bodies were added to the monitoring program in 2003 – Bright and Butler Ponds. The lake monitoring has been conducted by Aquatic Environment Consultants, Inc., following procedures established in previous years to ensure the data collection was compatible with previous data. By using similar methods and comparing data, long-term trends can be studied in the water quality of the lakes.

Invasive Plant Invades Reston Lakes - Purple Loosestrife, Lythrum salicaria

RA is locating, mapping and removing the Purple Loosestrife from Lake Newport and all other lakes to try to eradicate this plant from Reston.

Purple loosestrife is a very aggressive exotic weed introduced from northern Europe during the mid-1800s and is now invading Reston’s lake shorelines. Although attractive while blooming, established plants send up several stalks, each containing 300,000 seeds. If left unchecked, purple loosestrife can take over acres of shoreline, out-competing native plants for growing space.

Reston Association first noticed purple loosestrife on Lake Newport and discovered it on Lake Anne during the National Lake Survey on July 12, 2007. RA would like to remove all of the purple loosestrife that we find along the lakes. We are lucky that there are only small infestations of the plant, which makes it amenable to being pulled by hand, preferably before seeds set. We encourage landowners to grant us permission to remove the plant from private property along the lakes.

If you notice purple loosestrife on Reston Association property or if you have it on your own property and would like us to remove it, please contact the Watershed department, watershed@reston.org, 703 435 6535.

For a detailed fact sheet on purple loosestrife click here. The information in linked pages is not produced or monitored by Reston Association. Reston Association is therefore not responsible for the information contained in these linked pages.