Lisbon Drainage Master Plan

Contracting entity:
Câmara Municipal de Lisboa (Lisbon City Council)

Project description

This study intended to update and review the information and interventions prosed in the previous Lisbon Drainage Master Plan, ensuring that the interventions to be prioritized for 2016-2030 are compatible with the PGDL and city evolution, including the revitalization of Lisbon neighbourhoods. The PGDL (2016 – 2030) totalizes a catchment area of approximately 10 000 ha with 701 050 inhabitants (INE, 2011) and 1 430 km network. The PGDL review focused mainly on stormwater drainage systems and flood control, and was elaborated with the following main objectives:

• Update the information on the main stormwater drainage system, considering the works carried out till present and those planned within a short term period.
• Compare flow estimates presented in PGDL with the existing results on precipitation and flow monitoring.
• Check to what extent a set of planned interventions are compatible with PGDL, for the current mandate, and are considered as a development opportunity.
• Review PGDL interventions plan, determining which solutions envisaged in the plan are still compatible with the current interests, proposing alternatives if need and prioritize each intervention estimating its costs.
• Analyse the solutions proposed for flooding mitigation in PGDL and propose preliminary solutions to control floods in critical Lisbon areas.
• Identify additional sections in the drainage system where monitoring is needed and submit a register updated plan, given the priorities defined herein.

The recommended solution fell on the construction of two tunnels, Monsanto – Santa Marta – Santa Apolonia tunnel (approximately with 5.5 m inner diameter and 5 km length) and Chelas – Beato tunnel (approximately 1 km long and 5,5 m inner diameter). The solution also encompassed structural solutions such as detention/retention/infiltration ponds; reinforcement and rehabilitation of main trunks and secondary networks; diversion weirs and source control solutions and, soft solutions such as monitoring and warning system programme; training and capacity. Investments amounted to approximately 114  M€ (2016-2020) and 64  M€ (2021-2030).

Name of Associate Consultant: ENGIDRO – Estudos de Engenharia, Lda. And BLUEFOCUS.