Client: Municipality of Nicosia
The main objectives of the project was the elaboration of a hydrologic study for the Pedieos river reach between the bridge south of the Presidential Palace up to the bridge north of the old General Hospital, and a hydraulic study for the dimensioning of the active streambed to route flood events return period of 2, 5, 10, 25, 50, 100, 200 and 500 years, so that the area is not submerged.
The tasks that were successfully completed were:
- The present day conditions of the active channel and the floodplain were surveyed, itemized and the required reconstruction/ cleaning was recorded
- The rainfall record of M.S.640 at Nicosia for various intensities and return periods was evaluated
- The 12 catchments of Pedieos and of its tributaries were determined
- The time of concentration for each catchment was determined with a number of methods and a final value was selected
- The flow at various return periods was determined on the basis of flow data for two major catchments and with the rational formula for those that flow data were not available
- The software HEC – RAS (Hydrologic Engineering Center River Analysis System of the Army Corps. Eng.) was used to project the space and time movement of a flood event in the streambed providing the water level of the flow and the ability of the channel to contain the flood, under present conditions
- The velocity of flow and the stability of the channel slopes and of the streambed section were evaluated
- Recommendations for the dimensioning of certain sections of the stream were put forward
Main conclusions and recommendations:
- The streambed in the area studied has an active channel width varying between 10 to 40m or mean width of 25m.
- Erosion is limited and the stream is stabilized due to the extensive vegetation.
- It is concluded that the natural floodplain can accept and route floods of up to 500 years return period. Some problems may be expected at the Irish-type bridges.
- As a general conclusion the Linear Park traversing the active channel or the flood plain should be elevated above the active channel.