Water Quality

Water Testing

 

We test to get required data for our DEQ chemical treatment permits. Test data is done every year and documents the health of the lake.

1. Temperature: A lake with uniform water temps mixes easily and supports fish population. Lake Sherwood mixes easily top to bottom which is very good.


2. Dissolved oxygen: A high dissolved oxygen percent saturation is good for aquatic organism and is an indicator of a healthy lake. Lake Sherwood measures high which is very good.

 

3. Phosphorus and nitrate nitrogen testing: Lakes with a phosphorus concentration of 20 parts per billion or greater are considered to be nutrient-enriched and result in abundant plant growth. Lake Sherwood phosphorus range 19-28 (still high) & nitrate range 65-309 (normal).

 

4. Chlorophyll A testing: This test estimates algae density. Chlorophyll is still high in canals probably because of lawns versus water ratio. More resident help is needed.

 

5. Water Clarity: Secchi disk readings are taken throughout the summer season. Lake Sherwood 2005 readings were very good. See next page for more details on Secchi disk readings.

 

6. Bottom Sedimentation: Analysis show that organic material is building up which is aging the lake faster than normal. Residents need to rake more and should not re-sand their beach.

 

 

2022 Water Quality Study has been conducted on the water quality of Lake Sherwood by LSA’s limnologist Dr. Jude. If you would like to download a pdf copy of this report, please click here.

Standard Aquatic Vegetation
Summary 2006 Standard Aquatic Vegetation Map 2006
Water Car Guide (Huron Valley Watershed)

 


Testing for Water Clarity -Secchi Disk


From June to Sept weekly data are gathered on water quality clarity. The process consists of lowering an 8 in. dia. disk (painted in black & white quadrants) into the water until it can no longer be seen clearly. The disk is attached to a line that can measure distance into the water. This is done by the same person, at the same place, at approximately the same time of day. 2005 data reported clarity depths of 5'3(the shortest depth) on May 6th, to 13'6 (the deepest depth) on June 1st. Data is included in our annual Water Quality Studies report by Dr. Fusilier, our limnologist.

E. Coli

Oakland County Public Health does have the Driftwood A-lot beach on its roster for E.Coli testing. They conduct tests on a five year rotation with other residential beach fronts. The association has worked with Oakland Country to add other beachfronts on their testing site list. If you want to conduct E. Coli testing of your beachfront, you must follow the correct procedure to make the information meaningful. One water sample from any given beach will not give you useful information. Three samples must be taken at one time and then the process must be repeated five times within 30 days to get an idea of the geometric average of colonies at your beachfront. Results of E. Coli testing are only indicative of the area sampled, not the lake as a whole. If you would like information on the correct procedure to collect water samples, contact our lake director or you can go to Oakland County Health, 1200 N. Telegraph Road, Pontiac, 810-858-1312. They will provide you with sample bottles and a xerox of the correct collection procedure.

 

What are some factors that contribute to high E.Coli colonies?

Wildlife (ducks, geese, & seagulls), Weather Conditions (hot temperatures), Wind Direction, Storm Water Runoff, Number and frequency of swimmers, Land Development, and Land Use (dog feces not removed from yards) and Malfunctioning Septic Systems.

 

 

 

Weed Control

The following is a list of different types of algae found in our lake:

Planktonic Algae: Looks like pea soup or paint, green or brownish appearance. Natural die-off may cause summer kill of fish due to oxygen depletion.


Filamentous Algae: Also known as “pond scum” or “moss”, it usually begins its growth along the edges of shore and “mushrooms” to the surface buoyed by the oxygen it has produced.


Chara, attached-erect algae: Gray-green or yellow, this algae is often mistaken for plants. Chara has a hollow stem with leaf-like structures and has a musky odor and gritty, bristly feel. Water is usually clear.

Fanwort: Leaves on stem are fan-shaped and dissected into many narrow segments; flower is white to light yellow. In 2005 it clogged Upper Lake Sherwood, just north of us. It is invasive and very hard to treat. It is used for aquarium tanks because it flourishes so well. 

Photos of algae and weed plants common to Lake Sherwood

 

 

Chemical Treatment

 

WATERING GUIDELINES DURING WEED TREATMENT: Watering restrictions after chemical treatment vary from ―non to ―indefinite. Sometimes lawns get watered during a watering restriction. Since the chemicals are weed killers, watering probably (no guarantee) won't cause damage to the grass but would affect delicate flowers and vegetable gardens. When installing automatic sprinkler systems, try to separate the flower/vegetable zones so that these zones can be turned off separately during entire restriction period.

Treatments: The first scheduled treatment is for the entire lake. Then treatments are done as needed. Alternate methods of weed eradication have been researched and chemical treatment is the best choice for our lake.

Treatment Notification: Posting is required every 100 feet on the shoreline. Residents need to provide a wooden post (or tree) at their shoreline area available for a posted notice. Posting will show 1 day swimming restriction when treating; this is to ensure that residents stay off the lake while treatment is being done.

Chemicals used to treat weeds in Lake Sherwood

* Herbicide: There are two kinds of herbicide. Contact herbicide destroys the exposed portion of the plant that the herbicide contacts. Plants will re-grow in about 6-8 weeks and will have to be treated again. Contact herbicides are less expensive. Systemic herbicide is absorbed by the plant and effects its growth. A systemic herbicide will knock down the vegetation for much longer than a contact herbicide, but it is double the price and sometimes only affects certain plants.

Reward (Diquat dibromide): Do not use the treated water for swimming for 1 day (MDEQ restriction). Do not treated water to irrigate turf or non-food crops for a period of three [3] days after treatment. Do not use the treated water for watering food crops, animal watering (farm stock -- not incidental drinking by a domestic pet), or drinking purposes for a period of five [5] days after treatment. There is NO restriction on fish consumption. Diquat dibromide is the active ingredient. No swimming restriction exists on the federal label of this product.

Navigate / Aquakleen (2,4-D): Do not use the treated water for swimming for 1 day (MDEQ restriction). Do not use treated water for irrigating plants, mixing sprays for agricultural or ornamental plants, watering dairy animals, or domestic water supplies. "Irrigation" includes watering gardens --however it does NOT include established grasses. Domestic use means using lake water inside your house. There is no restriction on fish consumption. 2,4-D is the active ingredient. No swimming restriction exists on the federal label of this product.

Renovate 3 (Triclopyr): Do not use the treated water for swimming for 1 day (MDEQ restriction). Do not use treated water for irrigation of any plants except turf grass for 120 days or until the active ingredient has dissipated below a non detectable level as determined by water testing (usually after 2 weeks). This restriction does not apply to established turf grass watering. There is no restriction on fish consumption. Triclopyr is the active ingredient. No swimming restriction exists on the federal label of this product.

Aquathol-K, Super Aquathol-K, Hydrothol-191 (Endothall): Do not use treated water for swimming for 1 day (MDEQ restriction). Do not use treated water for lawn watering for a period of 7-14 days. Do not use treated water for household uses, animal watering [farm stock], or similar uses for 14 days. Do not take fish for food use or feed use for a period of 3 days. Endothall is the active ingredient in each of these products. No swimming restriction exists on the federal label of this product.

Sonar/Avast (Fluridone): Do not use the treated water for swimming for 1 day (MDEQ restriction). It is suggested that lawn and garden watering be restricted from 7 to 30 days. The suggested number of days depends on the rate applied and whether you are on a lake or canal and the type of irrigation. The sign we post when we treat will give the details for your area. Fluridone is the active ingredient. There is no restriction on fish consumption. No swimming restriction exists on the federal label of this product.

Cygnet Select (Water Dye): Do not use the treated water for swimming for 1 day (MDEQ restriction). No restriction for fishing and watering. Organic dye is the active ingredient. The label restriction for swimming is "several hours" after application or after even mixing.

Copper Sulfate / Chelated Copper / Earthtec (Copper based algaecides): NO WATER USE RESTRICTIONS. Informational posting only.

 Komeen/Nautique(Copper based herbicide): NO WATER USE RESTRICTIONS on the federal label. Informational posting only. MDEQ recommends a 24 hours swimming restriction.

Rodeo/Eagre/Shoreclear (Glyphosate): Used primarily for lily and emergent plant control. The active ingredient is Glyphosate. There is a 1day no swimming restriction (MDEQ restriction). There is no restriction on watering or fishing. No swimming restriction exists on the federal label of this product.

 

Homeowner Weed Control

  • To remove aquatic weeds from shoreline use a light aluminum 30 lake rake and pile on dock or grass to dry; then put in yard waste container.

  • To remove filament algae use a skimmer net.

  • If weeds are heavy, use a pitchfork to lift bunches of weeds.

  • A rake cutter can also be helpful in getting rid of plants growing on the bottomland.

 

 

Water Levels

WATERING: In 2005 a 20-year MSU study found that Michigan grass needs only an 8-minute mist mid-day to stay cool and therefore green. If resident watered an hour every day (assuming a 1 1/2” inlet, 1 1/2 HP/40psi, 21gal/min), it would take approximately 500,000 gallons/day, twice our lake's well pump supply. Save your pump and electric bills by using this new watering method.

AUGMENTATION WELL PUMP: There is one well pump (on Leafwood) and three natural water inlets; Wildwood Canal (Teeple Lake), Driftwood A-lot culvert, and Commerce Road/Jungle Island culvert (Cranberry Lake). The well received a new pump in 2007, is turned on from April through October, and is maintained spring and fall with “pool chlorine” to combat bacteria sulfates. The well pumps approximately 230,000 gallons of water a day into the lake. The annual electrical cost of running the pump is budgeted at $2400. Additional larger well would cost $10,000 (feasibility study), $400,000 (well), $9,000-$24,000 (annual maintenance). Spring rain, groundwater and evaporation are major factors for lake level and not the well pump.

LAKE WATERSHED: Part of the Huron Valley water shed system. Incoming water flows from Teeple Lake (Highland Recreation) and also Tray Lake/Cranberry Lake. It then flows through Lake Sherwood and into the Huron River, east of Milford. Sleeth Road Dam runs 1,600 feet long, measures 100 feet at top and 200 feet at bottom.

DAM: The lake's only outlet is the Sleeth Road dam. Stop logs (wood boards) are put in place from April through October to bring lake levels up approximately 18 inches. Boards are removed during the off season to lower lake level and allow shoreline to dry out (helps weeds to die off) and prevents ice flows from reaching and damaging seawalls.

Under Michigan Dam Safety Act 1994, LSA is required to have the dam inspected for safety, function, maintenance, etc. Last inspected Oct 7, 2005 by Gary F. Croskey, P.E., Dam Safety Consultant, 336 University Drive, East Lansing, MI 48823. (Previous inspections 1994 & 2001). Spring rain, groundwater and evaporation are major factors for lake level and not the dam after all the boards have been installed for the summer.

If the dam “fails”, an emergency action plan on file with the DNR instructs residents on either side of the dam to call the dam operator, who would contact Oakland County Emergency Response & Preparedness (248-858-5300), Oakland County Sheriff (911), Commerce Police, MDEQ (1-800-292-7800), and Oakland County Rd Commission.