Lake Flooding 2003

Why does the lake flood?  The lake receives water from the Grand Glaize watershed and receives the water through 2 pipes along Kinsale Dr.  As the lake rises, the water flows into the lake overflow, which is essentially a large concrete box which connects to a large culvert running under Dougherty Ferry Road and eventually to the Meremac River.  The overflow is protected by an iron grate, which keeps large objects from washing in.  A picture is displayed at right.

Unfortunately, debris washes into the lake and collects on the grate and eventually blocks the overflow.  Some of this debris is natural and resulting from creek erosion and other activities.  Most of the debris is clean cut however, and reaches the lake because of residents of our own subdivision, and other neighboring subdivisions dumping yard waste and tree trimmings into the creek.  This activity is both illegal and damaging to the environment, as well as costly to the subdivision.  Once the grate is clogged (as shown at right from the most recent flooding), the lake can rise and breach the dam in as little as 20 minutes due to the large amount of water that passes through the lake during heavy rains.  Before breaching the dam, the lake must rise to approximately 5 feet above the natural level.  The picture at right was taken when the lake was still 1 foot above flood stage.  This pile of debris on the grate was over 4.5 feet tall and covered the entire grate, which is approximately 12 feet long and 6 feet wide.  Some of the debris was logs in excess of 1 foot in diameter, and 7 feet long.  The widest opening of the grate is 5 inches.   The largest piece of debris ever pulled out was a tree trunk someone cut down that was over one foot in diameter and over 15 feet long.  When the dam is breached, the water exits the lake via the emergency overflow and into the ditches along Dougherty Ferry.  The emergency overflow is on the far east side of the lake.  When the lake floods, enormous pressure is put on the dam, and large whirlpool currents form in the lake.

Despite the efforts of residents along the lake to clean the grate after rainfalls, the subdivision still must pay approximately $500 to have the debris hauled away every time there is a heavy rain. 

What can you do?  Please report anyone you see dumping yard waste or tree trimmings into the creek, lake, or storm drains to both the trustees as well as the police.  Additionally, please follow through with the efforts for getting the City of Manchester involved with creek improvements.  The creek improvement page is here if you need more information.

The bottom picture at right, shows the creek on the south side of Dougherty Ferry Road that receives water from the lake after it passes through the overflow.  The picture was taken after the water had already receded approximately 4 feet.