Berm Openings

Kaelepulu Stream Mouth Openings, 2014

The following recommended opening schedule for the Kaelepulu Stream mouth was sent to several engineers and the director of the City’s Department of Facilities Maintenance in early December, 2013. No commitment for openings has been received.

Month Day Time
Jan. 28, 08:00
Feb. 25, 08:00
Mar. 24, 16:00
Apr. 15, 08:00
May 13, 08:00
Jun. 11, 08:00
Jul. 09, 08:00
Aug. 04, 16:00
Sep. 01, 16:00
Oct. 08, 08:00
Nov. 05, 16:00
Dec. 02, 14:00

Kaelepulu Stream Mouth Openings, 2013

The ELRA board has been working with the City Department of Facilities Maintenance to improve the efficiency and scheduling of stream mouth openings at Kailua Beach.  When the sand removal at the stream mouth is timed correctly with the tides it results in a good exchange of water between the pond and the ocean and in increase in the water elevation within the pond.  This exchange improves water quality in the pond, allows fish larvae from the ocean to come in, and allows large fish to go out to sea.  If the opening is not timed properly with the tidal cycle, then the exchange can be poor and water level elevation within the pond can drop to very low levels.

The water surface elevation of the pond falls by about a quarter of an inch per day from evaporation.  So, over a period of a month the evaporation removes about 7 ½ inches of water from the pond.  During months when we don’t get 7 ½ inches of rain (June – September), this means that the elevation of the pond will fall unless supplemented with inflow from the ocean.

The ELRA provided the City with a list of “best” days and times to open the berm in coordination with the tides.  So far this year (Early October) there have been seven stream mouth openings conducted by the City.

DateOpened at Recommended Date     and     Time ?Total Days OpenedPond Higher after exchange?Total Exchange
January 29NO                    NO1NoPoor
February 27NO                    NO0.5NoPoor
April 9 Yes                   NO5NoGood
June 5Yes                    NO0.1NoAlmost None
July 10Yes                    Yes5NoGood
August 23Not Opened due to Permit & BMP ProblemsNone
October 21Yes                  Yes1NoPoor

 

The opening for November is scheduled for the 18th or 19th. The opening for December is not set yet, but best would be the 2nd. An alternative would be the 16th.

 

The graphic below shows how multiple openings (arrows) at the wrong time of the tide, allows the water to run out of the pond, but not back in due to the narrowness of the channel.

Lake levels related to tide levels