Project overview:
The SNAM compression station in Sulmona (Case Pente) is a strategic infrastructure project that forms part of the Adriatic Line pipeline system, aimed at strengthening gas transportation capacity throughout Italy. Supported by investments linked to the National Recovery and Resilience Plan (PNRR), the project is expected to be completed by June 2026 and will increase the network capacity by approximately 14 million m³ per day, despite years of environmental protests and local legal appeals.
The project includes the design and development of a comprehensive stormwater collection, attenuation, and discharge system intended to regulate and control the release of rainwater from the facility. The system has been engineered to limit the maximum discharge flow rate at the release point through a dedicated pumping station specifically programmed to manage the stored stormwater volumes.
The drainage network is divided into two independent functional sections serving the western and eastern sides of the plant respectively. Both systems collect stormwater runoff from the southern boundary of the site and convey it toward a dedicated attenuation basin. The western drainage network also serves the central turbocompressor area, which is paved with interlocking concrete blocks, as well as the facility’s main internal roads. This section handles a maximum flow rate exceeding 430 l/s and serves an equivalent drainage area of approximately 22,000 m². The eastern section, on the other hand, manages a drainage area of over 10,500 m² with a maximum flow rate of around 200 l/s.
The drainage infrastructure has been designed using PVC-U pipelines compliant with UNI EN 1401 and UNI 10972 standards, featuring SN4 ring stiffness and SDR 41 classification. The pipelines are installed in trenches with a minimum cover depth of 80 cm, while manholes and associated structures follow dedicated technical construction specifications. Hydraulic calculations for the system were developed using the Gauckler-Strickler and Chézy formulas, taking into account flow velocities, filling ratios, runoff coefficients, and storage effects for larger diameter pipelines. More conservative roughness coefficients were adopted for pipes with diameters below 200 mm to ensure additional reliability in the hydraulic performance analysis.
Particular attention was given to the maintainability and long-term efficiency of the network. Inspection chambers, catch basins, and manholes were designed to facilitate inspection and periodic maintenance activities, helping prevent sediment accumulation and ensuring proper hydraulic performance over time. Each collection point was dimensioned to manage a maximum discharge capacity of approximately 3 l/s.
The scope of work included the 3D modeling of reinforced vibrated concrete manholes, complete with cast iron covers, gratings, and catch basins, using AVEVA E3D software. The activity also involved the modeling and routing of the pipeline system connecting the manholes, ensuring the proper conveyance and management of stormwater throughout the entire facility.
