Johns Lake Water Level

Johns Lake Water Level

It’s High!

Stormwater Drainage Area, Outflow and Lake Levels

Johns Lake is located in west Orange County and east Lake County. The lake level is dependent on rainfall in an area (basin) comprised of 26 square miles. No streams or springs are known to enter the lake. This basin is located south of Lake Apopka as shown on the following maps outlined in red. The watershed includes fourteen contributing lake systems located primarily to the east of Johns Lake. Surface flow moves generally from east to west through the interconnected lake systems and associated wetlands sloughs. Discharge from Johns Lake is conveyed north to Lake Apopka through a series of cross culverts and open ditch segments. Some of the lakes that flow directly into Johns Lake are, Black Lake, Lake Tilden, and Lake Yarbo. Water levels in these lakes is generally consistent with Johns Lake.

The lake level is not controlled by any agency or group. During periods ofhigh water, the water will flow northward into Lake Apopka. (See the blue line in the current & next map) During the dry season water flow stops for the most part. The water level of Lake Apopka is on average approximately 20 feet lower than Johns Lake. Lake Apopka lake level is controlled via a series of locks and dams by St Johns River Water Management District. While they are interested in the amount of flow from the Johns Lake Drainage Area, they do not monitor it, nor the lake level.

The lake level as of 8/4/2018 was approximately 99.36 NAVD88. ( North American Vertical Datum of 1988 is the vertical control datum, or base measurement point established for surveying elevations .) The FEMA base 100 year flood elevation for the entire basin is determined to be 99.7 NAVD88. See the map below – you can use the URL listed to look at the flood elevation at your location.

Water is currently flowing about as fast as it can through the various culverts as depicted in the pictures on the following pages. One concern is that very little of the outfall canal/pathway is deeded to preserve integrity of hydraulic flow capacity and maintenance. The City of Oakland has maintained the pathway from Hwy 50 to Lake Apopka, but the pathway from Johns Lake to Hwy 50 crosses two privately owned parcels.

Culvert structure on the south side of Hwy 50, looking west
Culvert structure on the north side of Hwy 50, looking south west. Water is flowing well under Hwy 50, but the culverts are at maximum capacity.
Gate structure just north of Hwy 50. Gates are locked in full open position, and water is not blocked.

Due to recent high water, many docks are either underwater or very close. High water has created danger of submerged docks and posts. Boat wakes cause damage to structures at or nearly under water and cause boards to break free. This is costly for the dock owners and it creates a significant safety concern. Boat wakes are also causing lakeshore erosion in areas where owners have removed all vegetation, and have not planted desirable vegetation. Please be considerate, slow down and use caution as floating boards have already been spotted.

The high water is also causing vegetation to break away and create floating islands that could cause harm to boaters at night. The canal between Johns Lake and Black lake is navigable to the Greenspace Park, recently created off Avalon Road. During Hurricane Irma this canal became blocked to boat traffic with vegetation, so we worked with Orange County to get it cleared. Recently this canal became obstructed again but has been reopened. FWC (Florida Fish and Wildlife Conservation Commission) was out on the lake this weekend to survey the islands and determine the best way to remove them. If we get an update, we will be certain to update you all. 

The high-water situation is unlikely to change anytime soon, and with more rainy months ahead, it will likely worsen. Looking ahead: we are in hurricane season and tropical storms could amplify the problems.

Johns Lake Water Level Fluctuations Illustrated

In a previous edition of Cattales, the variability of the water level on Johns Lake was discussed. In that article, we talked about the fact that every approximately 20 to 30 years, extreme drought conditions cause the lake level to drop precipitously and expose large areas of the lake bottom to the drying elements of sun and wind. While this has a temporary but profound dampening effect on the recreational use of the lake, it affords the lake bottom the opportunity to naturally rid itself of accumulated muck and organic materials that may have gradually accumulated over the preceding years. After a period of time the drought conditions lessen, the rains return and the lake levels are restored …but with significantly less muck and organic material on the lake bottom and a much healthier lake. The following two aerial photos were taken in 2001 and illustrate this dramatic phenomenon.

Johns Lake Improvement Association Financial Statement

Johns Lake Improvement Association Financial Statement

For year ended 12/31/17

Balance at 01/01/17
Member dues
Interest received
Balance with income
Cattails mailings
Corporate filing fee
P.O. box annual fee
Commercial service charge
Donation ONP
Donation FOLA
Total expenses
Balance at 12/31/17

State and Local Agencies

Lake County Aquatic Plant Management
(352) 343-9419
Lake County Department of Environmental Utilities
(352) 343-3776
Orange County Environmental Protection Agency
(407) 836-7400
Florida Department of Environmental Protection (EDPA)
(407) 893-3303
St. Johns River Water Management District
(386) 329-1429 or (407) 897-4346
Orange Storm Water Management
(407) 836-7990
Florida Fish & Wildlife Conservation Commission
(407) 858-6170
Town of Oakland
Dennis Foltz – town manager (407) 656-1117, ext 2103

JLIA Board of Directors

Martin Davis
407 877-3455

Ann Megler
407 654-1269

Don Hickman
407 656-2392

Mary Louise Grable
407 656-2919

Johns Lake Boat Parade: Save the Date!

Johns Lake Boat Parade: Save the Date!

The 18th Annual Johns Lake Holiday Boat Parade will be held on Sunday, Dec. 16, 2018. We will be sending out information, and looking for volunteers to help.

Next Meeting

An announcement will be sent before the next meeting. Anyone wanting to attend is welcome. If you want to get more involved, this is your opportunity.

Share the News

Share this newsletter with your neighbors, and ask them to let us know if they want to receive information regarding our lake.

Do You Have Aquatic Midges?

Do You Have Aquatic Midges?

(aka blind mosquitoes)

     Aquatic midges, or blind mosquitoes, don’t bite, suck blood, or carry diseases, but they can be a real problem for homeowners on the lake. They can be beneficial as a food source for fish, and lakes where the midge breeds are the best fishing lakes. However, the nuisance created by these little bugs far outweighs the benefit. 

One of our JLIA members shared this photo:

     The aquatic midge has four stages in their life cycle: egg, larvae, pupae and adult. The eggs are laid on the surface of the water in a gelatinous mass that can contain upward of 3,000 eggs that will hatch in 2-7 days. The larvae then feed on that gelatinous mass for about 2 days, they then burrow into the mud and feed off organic matter in the mud and water. After a period of 2-7 weeks, they transform into pupae and swim to the surface of the water. Within hours, the adult midge emerges- then look out!! The adult midges usually emerge in large numbers between April and November. During the day, they hang out in cool shady place and swarm at night to mate, preferring the lighted areas around homes (pools, porches, accent lighting). They do not feed, so they only live 3-5 days, then the life cycle begins again.

     Midges eventually attract spiders, their natural predator. The accumulation of midges in the webs results in frequent washing of home exteriors. As these midges die and decay, they can produce an offensive smell similar to rotting fish.

     Their occurrence and survival often indicates the type and amount of nutrients found in the water. Attempts at control involving insecticides or fogging units only address the adults (who have shown to develop a resistance to pesticides) and can even be counter-productive if it kills the natural predators.  These attempts at control are only temporary as the next generation emerges rapidly. Midges breed in water that is excessively rich in nutrients, frequently caused by runoff from the land that contains organic materials, fertilizers (phosphates), among other materials. These nutrients stimulate the growth of aquatic plant life (such as algae), resulting in the depletion of oxygen. As nutrients increase, so does the population of midges.

Recommendation for lakefront residents:

  • Reduce the use of unnecessary outdoor lighting, and indoor lighting that will attract midges to the
    windows and building
  • Use a “light trap” in a corner of your yard to attract midges. Use of bug zappers is not recommended because they kill beneficial insects as well as the midges.
  • Prevent nutrients from entering the lake by eliminating debris at the lakeshore (leaves, grass clippings, etc.)
  • Prevent fertilizer (phosphate) from washing into the lake by maintaining barriers to prevent runoff
    and by not fertilizing between the barrier and the lake.
  • Consider planting aquatic plants that improve the waterfront by removing excess nutrients that the larvae feed on. Though this is a slow process, it help to improve the overall lake health and wildlife habitat.

All of this information and more can be found on the following University of Florida site.