Session A1 - Perspectives for the transposition of the EU Directive on stormwater management

Cerema is providing technical support to the Directorate for Water and Biodiversity (DEB) for the transposition of the stormwater component of the Directive. These considerations regarding the transposition of DERU2 on stormwater management aim to provide a national overview of the performance of systems as currently reflected in regulatory self-monitoring data, and, if possible, to identify areas for improvement and lessons learned beyond the purely regulatory aspect.

This article presents the process of developing Goiânia’s Urban Drainage Master Plan (PDDU), describing the technical institutional diagnosis, the structuring of a geospatial database, and the process of constructing management, vulnerability, and performance indicators, as well as the first results already incorporated by the municipal administration. The starting point was a context marked by the absence of an up-to-date register of stormwater networks, the recurrent occurrence of flooding, and asymmetries between legal frameworks and urban planning instruments, with a view to building an integrated approach that combines gray infrastructure, nature-based solutions (NbS), and indicator based governance. The results include the approval of a new drainage law aligned with the PDDU, the incorporation of standardized hydrologic parameters, the adoption of the plan’s protocols by Civil Defense, and the preparation of data for continuous performance monitoring. The study reinforces the centrality of reliable information, hydrodynamic modeling, and the use of indicators as instruments to guide decision making, prioritize investments, and reduce urban socioenvironmental vulnerabilities.

Cities and urban areas are pollution factories for water, waste, air, carbon and several other pollutants. As a society, it is critical that we build cities to be in harmony with nature and avoid polluting the places we love. This paper outlines how an integrated use of assets that are required to meet this goal, and demonstrates it is possible to design cities for stormwater volume reduction targets.  It requires a careful and methodological application of green roofs, rainwater tanks, infiltration systems, passively watered trees and trenches, raingardens and central median strips.  Examples range from 50 to 98% volume reduction, in projects at the lot to the precinct level.