Extremely invasive lake weed
October 14, 2021
Hydrilla sp. - cute name, but not so cute in our lake!
While collecting data around the lake, Mike has also been harvesting -
140 cubic feet of hydrilla.
"Hydrilla is a perennial plant that forms dense colonies and can grow to the surface in water over 20 feet deep. Hydrilla branches profusely and after reaching the surface it extends across it forming thick mats. Hydrilla can reproduce by fragmentation, from seeds, from turions (axillary buds), and from tubers. Leaves are blade-like about 1/8 inch and 3/8 inch long with small tooth margins and spines on the underside of the midrib that make them feel rough. Leaves are usually 4 to 8 in a whorl".
(ref: The Pond Guy)
Feel free to do some harvesting too.
Please make sure it is not disposed of in other water ways.
Our Lake - Keep it Healthy - Keep it Safe
Water Quality UPDATE 5-10-2021
According to our Water Quality Manager, Mike Casteel, Ph.D.,
we should remain at the CAUTION Level.
The water has been fairly clear algae free however, we should NEVER let down our guard and remain vigilant to any increases in visible algae.
If you see anything you think might be of concern please contact Mike at
tele. 434-400-8816
email: mjc@fig8.org
or any Board Member.
He will continue to monitor the lake for any changes as well.
The lake water quality is currently at CAUTION level.
Water quality update 9-3-2020
Figure 1. Composite sample of lake water collected on 8-22-2020; the picture on the left shows the sample immediately after collection; the picture on the right shows the same sample that was left undisturbed for 24 hours.
Accumulations of bright green material were observed on the surface of the lake on 8-22-20, and close observation of a composite sample collected on that date clearly showed both blue and green organisms (see Figure 1). These organisms were different than the filamentous algae that is routinely observed and that is abundant on the bottom of the lake (Fig. 2).
A sample showing green, filamentous algae (left picture). This type of algae is abundant on the bottom of the lake and most species are not considered harmful. When this type of algae dies, it floats to the surface and is often referred to as muck, scum, or mats (right picture).
Figure 3. Cyanobacteria attached to a floating, decaying strand of the aquatic plant Hydrilla(left) and other organic material (right).
Based on this information, blue-green algae (i.e., cyanobacteria) were considered to be present; consequently, lake users were cautioned (signs posted at beach / pavilion, mailboxes, and website) in regards to contact with the water. Presumptive cyanobacterial colonies ranging in size from a few millimeters (mm) to several centimeters (cm) (about one to a few inches (in.)) continued to be observed around all areas of the lake from 8-22-20 to 8-30-20, including the shoreline from the beach to the end of dam, and at distances up to 23 meters (m; about 75 feet (ft.)) from the shore. These organisms are occurring at various depths in the water column and are also found at the surface and attached to other organic material and aquatic plants such as Hydrilla (Fig. 3).
Precipitation event of 8-31-20. Runoff from the beach (left) and a large mass of cyanobacteria in the water immediately adjacent to the beach (right).
During and following the precipitation event experienced by the area on 8-30-2020 to 8-31-2020 (Fig. 4), larger colonies (some up to 25-30 cm) of cyanobacteria were observed in the lake, and these colonies have persisted as of 9-3-2020. A large mass of Hydrillaand other material, estimated to be about 3-4 m in diameter and containing cyanobacteria, was observed in the center of the lake on 9-1-2020
A circular (about 3-4 m in diameter) accumulation of Hydrilla and other material in the center of the lake. The beach is seen towards the upper right corner of the picture. Cyanobacterial colonies were observed in this material.
While some physical removal (followed by composting off-site) of accumulated organic material and cyanobacterial colonies along the shoreline from the beach to the dam has been performed (to date, >300 pounds has been removed).
Presumptive cyanobacteria continues to be present, and lake users should continue to heed the warnings and recommendations posted on the signs.
First report from new Water Quality committee
Water Quality Manager Dr. Mike Casteel (Microbiology, Water Quality)
As reported in the October 2019 edition of the GAPOA newsletter, testing of Greene Acres Lake (GAL) provided some preliminary information about the water quality of GAL. Water quality is defined as a measure of the suitability of water for a particular use (e.g., swimming; fishing; boating) based on selected physical, chemical, and biological characteristics. In summary, the 2019 data showed that the water quality of GAL is consistent with other freshwater lakes in North America, and that our lake continues to be safe for recreational purposes. However, further monitoring was recommended, because the results showed that GAL contains a level of phosphorus within or above the upper recommended limits compared to many other lakes in Virginia (different lakes have different limits, depending on location). The data also showed the presence of several different species of algae, some of which are well known to be associated with situations commonly known as harmful algal blooms (HABs).
Algae are microscopic organisms that occur naturally in freshwater ecosystems, including the species associated with HABs. Under certain conditions, algae can quickly multiply or "bloom" to a point where algal colonies become visible without the need for a microscope, and blooms may look like foam, scum, mats, or paint floating on the surface of water. Algal blooms can cause damage to aquatic environments by blocking sunlight and depleting oxygen required by other aquatic organisms, restricting their growth and survival, and some species of algae contain toxins that can cause adverse health effects to humans, wildlife, and other animals such as dogs. When algal blooms impair aquatic ecosystems or have the potential to affect human and animal health, they are known as HABs.
While the 2019 data indicate that there is currently a low risk of occurrence and exposure to HABs in our lake, the frequency and geographic distribution of HABs has been increasing regionally (e.g., Lake Anna; Chris Greene Lake), nationally and globally. Starting this month, some of GAL's water quality parameters will be monitored routinely, including water temperature, water clarity, and levels of phosphorus. In addition, routine visual observation of all areas of the lake will be performed, and local meteorological data will be collected and archived. Such information will be used as an early warning system for the occurrence of an algal bloom in GAL. For example, there is a higher probability for the occurrence of an algal bloom when (i) water and ambient temperatures are highest, (ii) there is an increase above normal levels of phosphorus, (iii) there is a cycle of intense and heavy rainfall followed by drought-like conditions, and (iv) there is a high volume of stormwater runoff in to the lake resulting in increased turbidity (cloudiness or less clarity) of the lake's water. If an algal bloom is observed, remedial action will be taken immediately. This information will also serve as a baseline of results for comparison to future monitoring efforts.
The GAPOA community is encouraged to contact our new Water Quality Manager, Mike Casteel, with any comments or suggestions, or to provide any anecdotal or historical information about GAL. Mike would be happy to discuss any water quality and environmental issues and to talk to residents about how they could participate (i.e., become "citizen scientists"). Working together, we will continue to ensure and protect GAL's water quality.
Contact:
Michael J. Casteel, Ph.D.
Figure Eight Environmental, L.L.C.
371 High Ridge Road, Stanardsville, VA 22973-2557
tele. 434-400-8816
email: mjc@fig8.org
Our Lake - Keep it Healthy
Lake Water Quality Reports
NEW INFORMATION ON LAKE USE! 09/23/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
Due to cooling temperatures and ongoing robust water quality testing, the lake water quality and use status have been assessed as CAUTION level.
Please follow the posted signs and adhere to the information provided.
INFORMATION ON LAKE USE! 09/02/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
Please take note of the latest updates
on the lake water quality. (Click on the above graphic to enlarge it).
Monitoring the lake water and an assessment of the lake water quality specific to harmful algae is ongoing.
Please follow all recommended safety precautions and posted signs.
Check back regularly for updates.
USE LAKE AT YOUR OWN RISK!
CONTACT Environmental Chair.
LAKE WATER UPDATE 09/01/2022
LAKE WATER UPDATE 09/01/2022
LAKE WATER UPDATE 09/01/2022
- Significant amounts of potentially harmful algae blooms have been identified at ALL of the testing sites around the lake.
This can significantly elevate the risk to anyone using the lake- including swimming, fishing, and other recreational water activities.
USE LAKE AT YOUR OWN RISK!
* Wash with FRESH CLEAN water as soon as possible after using the lake!
* DO NOT let your pets swim, play, drink lake water, or eat lake sludge!
* DO NOT fish - wash all equipment with FRESH CLEAN WATER, if they come into contact with lake water!
* DO NOT break up any algae blooms
* Monitor any deteriorating health conditions and seek medical help immediately!
Read and follow ALL posted signs at the lake, and on this website.
LAKE WATER UPDATE 08/22/20222
LAKE WATER UPDATE 09/01/2022
LAKE WATER UPDATE 09/01/2022
The Lake water quality status has been elevated to WARNING!
The report below explains the changes that have occurred, and what you can do to be safe under these conditions.
USE THE LAKE AND BEACH AT YOUR OWN RISK
To read the full report
click on this link
Lake Water Quality Reports
NEW INFORMATION ON LAKE USE! 09/23/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
Due to cooling temperatures and ongoing robust water quality testing, the lake water quality and use status have been assessed as CAUTION level.
Please follow the posted signs and adhere to the information provided.
INFORMATION ON LAKE USE! 09/02/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
NEW INFORMATION ON LAKE USE! 09/23/2022
Please take note of the latest updates
on the lake water quality. (Click on the above graphic to enlarge it).
Monitoring the lake water and an assessment of the lake water quality specific to harmful algae is ongoing.
Please follow all recommended safety precautions and posted signs.
Check back regularly for updates.
USE LAKE AT YOUR OWN RISK!
CONTACT Environmental Chair Fred Turck.
LAKE WATER UPDATE 09/01/2022
LAKE WATER UPDATE 09/01/2022
LAKE WATER UPDATE 09/01/2022
- Significant amounts of potentially harmful algae blooms have been identified at ALL of the testing sites around the lake.
This can significantly elevate the risk to anyone using the lake- including swimming, fishing, and other recreational water activities.
USE LAKE AT YOUR OWN RISK!
* Wash with FRESH CLEAN water as soon as possible after using the lake!
* DO NOT let your pets swim, play, drink lake water, or eat lake sludge!
* DO NOT fish - wash all equipment with FRESH CLEAN WATER, if they come into contact with lake water!
* DO NOT break up any algae blooms
* Monitor any deteriorating health conditions and seek medical help immediately!
Read and follow ALL posted signs at the lake, and on this website.
LAKE WATER UPDATE 08/22/20222
LAKE WATER UPDATE 09/01/2022
LAKE WATER UPDATE 09/01/2022
The Lake water quality status has been elevated to WARNING!
The report below explains the changes that have occurred, and what you can do to be safe under these conditions.
USE THE LAKE AND BEACH AT YOUR OWN RISK
To read the full report
click on this link
Restocking of Grass Carp at the Lake on March 21, 2023
Stocking for Aquatic Vegetation Control
Stocking for Aquatic Vegetation Control
Stocking for Aquatic Vegetation Control
150 sterile Triploid Grass Carp were released into the Greene Acres lake on the evening of March 21, 2023. Grass carp, under good conditions, are used to help control aquatic vegetation. Permitted under the Virginia Wildlife Resources (DFV)
Give them time to do their job
Stocking for Aquatic Vegetation Control
Stocking for Aquatic Vegetation Control
Under good conditions, a five-pound fish will eat about five pounds of aquatic plants a day.
Our newcomers need at least 12 months to settle in their new home - so if you catch one, please gently release them back into the lake.
There are bigger fish to catch!
Carp ready to take the plunge at GA
Stocking for Aquatic Vegetation Control
Carp ready to take the plunge at GA
Grass carp generally only consume submerged vegetation that has soft/tender, non-fibrous stems and leaves. Some common plants they will readily consume are hydrilla, elodea, bladderwort, coontail, najas, milfoil, potomegton spp. (pondweeds), chara, and nitella.
