SNAM plant green area
The project involved the irrigation system for green areas within the SNAM plant at the Tarsia town (in Italy). The total area is about 12 hectares and is composed of green lawn beds. The terrain is purely flat.
Through a well the water is collected in an accumulation tank that hydraulically separates the constant flow coming from the well and the irrigation system that requires higher flow rates and shorter durations. The pump that feeds the irrigation system from the accumulation tank has been sized for the different shifts so as not to exceed the volume of compensation.
The plant is composed of more than 3000 m of DN90 main pipelines and problems of different crossings for existing works have been tackled. Several sectioning solenoid valves have been inserted so as to divide the main network and command which sections to engage and which to exclude.
In order to manage the 19 shifts, made up of groups of sectors chosen to balance the flow rate around a set average value in the various shifts, 56 solenoid valves and two control units have been provided to control the valves and the pump in two groups.
Targets of the project
The timing of the shifts was drawn up as to:
- have a similar flow for each turn
- cover irrigation within a day
- verify the equivalence between the incoming and the outgoing volume from the supply tank
- simulate further hydraulic conditions.
The turf of the green areas is irrigated with more than 500 pop-up sprinklers (dynamic and static), while the perimeter part with hedges and shrubs is irrigated with dripping (self-compensating) laterals. The pluviometric overlap of wet circles and the uniformity of distribution was verified. More than 40 pressure reducers have been inserted to keep the pressure below certain limits in some areas of the system (especially for the drip part which requires less pressure to operate).
In the project, different scenarios were assessed (some discarded due to lack of uniformity, efficiency and balancing of flow rates per shift), and finally chosen the one that at the same time reaches the daily requirement to irrigate the entire surface, has an adequate intensity of rain, an acceptable uniformity and is compatible with the conditions of compensation, volume and flow of the source.
