Merimbula Lake is an inlet/lake system comprising a natural entrance, inlet channel, substantial marine delta into a large medium depth (3-4 metres) basin, and a much smaller southern shallow (0.3m) basin. Much of the major basin has a rocky shoreline, whilst the small basin shoreline is mangrove and sand based.
Merimbula is situated along the northern side of the inlet to Merimbula Lake. The Princes Highway joining Merimbula and Pambula (to the south) crosses the inlet at its narrowest point via a constrictive 250 m long causeway and relatively short bridge. The inlet and causeway offer considerable resistance to tidal penetration. Although the construction of the 200 m causeway in 1909 altered the hydraulic regime, records show the lower estuary channel and shoal patterns to be unchanged, suggesting that the impact of the causeway on overall hydraulics was not great. Mean lake level is super-elevated 0.25 m above mean sea level. Spring tidal velocities up to 2 m/s have been measured midway through the ebb cycle in the bridge throat area. There is no record of the entrance ever having been closed, and bar depths (1.4 m at low tide) are approximately unchanged since first European settlement.
You should have a sign near you giving lots of information. As the last Ice age came to an end the sea levels gradually rose to today’s level. The incoming sea slowly flooded valleys and washed sand back from the continental shelf to the changing coastline. Sand washed onto the shore by persistent wave action has formed a sand barrier and enclosed a body of water, reducing the estuary mouth to a narrow channel.
To log this cache send an email with the following answers.
1. How many years ago would you have been standing on a flood plain of a small river?
2. 7000 years ago you would have been standing in the froth of ______ ?
3. Is the water in the lake at this location fresh, salt or brackish(combination of salt + fresh)? (not on a sign, take a guess)
4. Post a photo of yourself and GPS (in your log) with the lake in the background. This is an option and not required to log the cache. Don’t put any of the answers in your log or it will be deleted.
If you do not send an email with your answers your entry will be deleted. Feel free to log this cache before sending an email, incorrect logs can be deleted.
I hope you enjoy your visit to this magnificent area.
Information for this cache is from Parks NSW and information signs around the board walk.
Before venturing into Parks check out the following web site for more info.
http://www.environment.nsw.gov.au/parksafety/
http://www.environment.nsw.gov.au/NationalParks/FireClosure.aspx
http://www.environment.nsw.gov.au/nationalparks/default.aspx