Time-lapse cameras aid water monitoring in the Ramsar-listed Apsley Marshes

You may have heard about our eco-hydrological investigation into the Moulting Lagoon and Aspley Marshes Ramsar sites on the east coast of Tasmania (read more about the project here) – an important project we are delivering in partnership with NRM South and the Australian Government.

As part of the monitoring program at the Ramsar-listed Apsley Marshes in Tasmania, we installed two time-lapse cameras back in April 2022, on elevated hills adjacent the western margin of the mid and lower Marshes. These cameras have been actively taking images from set locations daily, at an interval of 30 minutes.

Map of monitoring locations in the Apsley Marshes, Tasmania (pink stars = time-lapse cameras; yellow dots = water surface level loggers)

The resulting imagery not only provides us with interesting insights to the fluctuations of water levels in the Marshes, but it also enables us to look at how the water level in the Marshes responds to rainfall and tide events. This visual catalogue is complementary to the water level data being recorded by our in situ water loggers (a preliminary analysis of which was shared in this previous article), also installed in April 2022, as part of the Apsley Marshes eco-hydrological monitoring program.

The images below show the water levels observed over about a week in August 2022 (13-21 August) and highlight the response of the western wetland to 30 mm of rain received in Bicheno on the 14th of August 2022. Within 24 hours water levels rose and remained elevated for up to one week after the rainfall event.

Time-lapse camera imagery for the Western Wetland, August 2022 (top = 13th August, middle = 15th August and bottom = 22nd August)

The images below were taken from the same locations after a 100 mm rainfall event which occurred in October 2022 over a period of four days (22-26 October). In this instance, water levels rose higher than those recorded in August; however, they receded over a similar time-frame. One week after the rainfall event, water levels had returned to previous levels.

Time-lapse camera imagery for the western wetland, October 2022 (top = high water levels on the 26th October, and bottom = water levels back to previous on the 3rd November)

The wetter than average La Niña conditions have extended over the spring period of 2022, and continued to bring high freshwater inflows from the Apsley River, so we are yet to experience any dry conditions. Observing dry conditions in the Marshes will allow us to to observe the sole effect of high tides on the lower Marshes. Hopefully with La Niña easing over summer and into autumn, we will begin to gain insights to the influence of Moulting Lagoon tidal movements on the Marshes, which is an important part of our investigation into the eco-hydrology of this special place.

The collection of images captured by the time-lapse cameras provides another tool that will continue to assist us in unravelling the mysteries of the gem that is the Apsley Marshes.

This important work is supported by NRM South, with funding provided via the Australian Government’s National Landcare Program.

Bec Sheldon