“Prepare for the worse and hope for the best”.
Due to the number of calls we’ve had from customers and clients asking for advice on preparing for hurricanes, we are providing some general comments. Specific recommendations depend upon the characteristics of your watershed and lake or pond design. Nevertheless, these tips will help you know what to expect.
How hurricanes affect Lakes and ponds
Lakes and ponds are most affected by heavy runoff of rain water and huge amounts of pine straw, leaves and other organic matter that blow and wash into lakes. Runoff of extreme amounts of rain can overwhelm a lake drain system. The emergency spillway should allow excess water to flow around the end of the dam without serious damage. However, sometimes the emergency spillway is undersized, partially clogged with trees and vegetation or the amount of rain is simply too great for the design. Obviously, if another dam in the same watershed fails, extreme pressure may be put on your dam.
The most common lake problems we see with hurricanes are fish kills associated with depleted dissolved oxygen in the few days following the storm. Hurricanes often occur when the lake water is warm, stratified (warm at the surface, cold at the bottom) and stressed for dissolved oxygen anyway. Huge amounts of pine needles, leaves, grass clippings, mulch, sticks and other debris blow or wash into the lake or pond and rapidly begin to decay. The decay consumes the limited dissolved oxygen available and the fish die. Often the largest, most valuable fish die first.
Here's what you can do to prepare your lake or pond for the storm
Consider opening your drain valve
As a rule, we don’t recommend opening the drain valve before an expected hurricane approaches. Opening the valve a day or two before the storm is expected can lower the water level and provide additional storage for heavy runoff. However, you must consider your risks. If the valve has not been “exercised” at least once per year, it may be seized and not open or may not close after opening. There is a possibility a piece of debris will enter the valve and prevent it from being able to be closed. Also, you may be so busy with other cleanup activities you forget to close the valve after the water level returns to normal.
TURN OFF ELECTRICAL POWER TO AERATORS, FOUNTAINS, FISH FEEDERS AND OTHER EQUIPMENT
Fluctuations in electrical power can damage the equipment.
MAKE SURE ALL EQUIPMENT IS SERVICED WITH ADEQUATE SUPPLIES AND FUEL ON HAND
Fuel may be in short supply after the storm. Consider having at least minimal building materials on hand to make repairs
MOVE EQUIPMENT THAT MAY BLOW OR WASH INTO THE LAKE AWAY FROM THE SHORELINE
Move or securely fasten fish feed storage barrels, fish feeders, boats, chairs, fishing gear, irrigation pumps and other portable equipment.
LAY DOWN PLANT MATERIAL
If you have any potted plants, lay them over in a protected area or parallel to the direction of wind you expect.
MAKE SURE YOUR DRAIN TRASH RACK IS CLEAN
Remove existing leaves, sticks and debris from the drain so it can flow as effectively as possible. If you don’t have a trash rack, make one. You don’t want debris to clog the drain pipe. One inexpensive, easy to make device is an outer sleeve. Use a piece of single-wall corrugated plastic drain pipe, at least twice the diameter of your standpipe riser. Insert two short pieces of steel rod (rebar or concrete reinforcement rod works well) through the pipe about 12 inches from one end. The steel rods should cross, forming an “X” inside the pipe. As the plastic pipe is placed over the existing drain standpipe, the steel rod will rest on top of the standpipe. The top of the plastic drain pipe will extend above the water surface. Water from below the lake surface, containing much less debris, will enter below the outer sleeve and flow out the standpipe. Even if water does flow over the top of the outer sleeve, the crossed pieces of rod or pipe will prevent large sticks, turtles, etc. from clogging the drain.
MAKE SURE YOUR EMERGENCY SPILLWAY IS NOT OBSTRUCTED
Most lake dams have a wide, flat, slightly lower area at one end. This allows water to escape over the stable end of the dam when it exceeds the capacity of the drain system. Consider trimming weeds, trees and generally clearing the emergency spillway so it can flow unobstructed.
REMOVE LOOSE STICKS AND FIREWOOD STACKED ALONG THE LAKE SHORELINE
As many people trim trees along the lake shoreline, they stack it near the shoreline to be used for firewood. When the water level rises, due to heavy rain, the sticks and firewood float into the lake or pond. This may not be an issue this summer since we have had high lake water levels several times already.
CONSIDER HOW YOU CAN AERATE THE WATER AFTER THE STORM
Try to find a water pump that can be used to spray water onto the lake surface to provide supplemental aeration. You may not have electricity available. Can you power an electric pump with a portable generator? Can you get a gasoline or diesel fueled pump to spray water? Night time is the right time to aerate a lake. Oxygen is created during daylight, but is consumed by the lake organisms at night. Midnight until dawn is often the most critical time. If you see fish gasping at the surface, immediately begin pumping water. Even a relatively small spray of water, hitting the lake surface at an angle to create a current, can save the fish. Discharge the water spray at least 4 feet above the lake surface so it can absorb as much oxygen as possible while falling through the air. In a bind, you can even use an outboard motor to agitate and circulate the lake water.
DOWNLOAD THE "READYNC" APP FOR YOUR SMART PHONE
You will have local weather, road conditions, power outages, open shelters, evacuation routes, flood gages, disaster assistance and an emergency supplies list at your fingertips.
We all hope this hurricane gets swept out to sea. However, these tips will help you prepare and minimize damage to your lake or pond. We know from past experience how hectic the cleanup and recovery can be. Knowing what to look for and having some contingency plans makes sense.