Client: Birdlife Cyprus
Within the framework of the Darwin Plus project “DPLUS141: Habitat restoration and wise use for Akrotiri and Cape Pyla”, which was funded by the Darwin Plus UK, I.A.CO Environmental & Water Consultants was assigned by BirdLife Cyprus to conduct a Hydrological study for Makria Lake at Zakaki area in Limassol.
The Darwin Plus project aimed to restore and enhance key wildlife habitats within the Cyprus Sovereign Base Areas (SBAs), focusing on the Akrotiri wetlands and the native scrubland on Cape Pyla (Dhekelia), while also developing eco-tourism opportunities to support the local economy and encourage wise use.
The overall goal of the hydrological study was the identification of the hydrological regime of the Makria Lake for a thorough understanding of the Lake’s operation and water balance. Further to the hydrological study, an ecological assessment and a review of management options was carried out by the Darwin project, aiming to the rehabilitation of the habitat and the improvement of the conservation of the target species.
For achieving the Hydrological study’s goal and further objectives, the following tasks were implemented:
Task 1: Elaboration of a hydrological operation study
A comprehensive hydrological operation study was conducted in order to identify the hydro-morphological regime of Makria Lake. The hydro-morphological conditions, as well as the lake’s response to different rainfall events were determined, in order to provide a better insight towards deciding about any conservation actions related to an improved water management of the lake.
Within this task, the following sub-tasks were executed:
- A brief historical report regarding the hydrological regime changes of the Lake during the recent years, such as the development of stormwater drainage infrastructure with outlets discharging runoff water into the Lake, etc.
- Site visits for thoroughly understanding all hydrological features related to the Makria’s Lake operation conditions.
- Collection of all the necessary data facilitating the elaboration of an operation study, such as historical rainfall data, evaporation data, groundwater data, existing stormwater drainage networks discharging into to the Lake, high-resolution topographical survey data (LiDAR) from the Department of Lands and Surveys (DLS), etc.
- Development of the Storage-Elevation-Area curves of the Lake, which are essential for the implementation of the water operation study.
- Development of a water balance model for facilitating the Lake’s operation computations. The computations took into account all inflow sources, such as runoff from Zakaki’s stormwater drainage system, direct precipitation, groundwater seepage, losses such as evapotranspiration and overspill, etc. The computations were carried out in three stages: a) Inflow computations before evapotranspiration, b) Outflow calculations including evapotranspiration and overspilled losses, and c) Evaluation of the final Lake’s water balance.
- Production of monthly inundation maps based on the water balance results.
Task 2: Topographical survey of Lake’s basin
In order to develop a creditable topographical profile of the Lake’s basin, due to the existing dense reed vegetation which hinders any effective in situ surveying works, the latest available high-resolution topographical data (LiDAR) were obtained from the Department of Lands and Surveys (DLS), and a number of spot ground elevation measurements (using high accuracy GPS equipment) were carried out.
Task 3: Assessment of the water quality characteristics of the Lake
The assessment of the water quality of the Lake was conducted through a water sampling campaign. The sampling campaign was performed over a one (1) year duration, and was conducted as follows:
- Two (2) samples were collected from the existing culvert outflow into the Lake, and two (2) samples from the Lake itself, after rainfall events.
- Two (2) samples were collected from the channel that routes water from the Lake towards the Akrotiri Salt Lake.
Key Result
The hydrological regime of the Makria Lake has been changed over the year, mainly after the construction of stormwater drainage system (between 2003-2008) that discharges into the Lake. At the current conditions, the stormwater inflow into the Makria Lake is more than 95% of the total annual inflow of the lake, with a water quality that is related to an urban environment.
Makria Lake can retain less than 5% of the volume of water that inflows to it, as the remaining volume of water is overflowing towards the Akrotiri Salt Lake (500.000 to 800.000m3/year).
As a result, the role of reeds, its water purification potential and how these are purifying/filtering the water quality that overflows towards the Akrotiri Salt Lake, such as their ability of extracting nutrients from the water column and Lake sediments, improving the quality of the water flowing into the Akrotiri Salt Lake, must be taken into consideration.
