The refurbishment of Gomeznarro park in Madrid focused on storm water retention (2014)
As a result of its topography and impermeable ground surface, the Gomeznarro Park in Madrid was affected by erosion during heavy rainfall events, and the surrounding residential areas suffered from flash flooding. In response to these problems, in 2003 complex works aiming at improving the natural drainage and rain water retention were carried out in the park. These included removal of impervious pavement and use of permeable surfaces, restoration of compacted soils, revegetation of the areas at risk of erosion and installation of underground rainwater collection system and storage tanks. These measures eliminated the problem of erosion and flash flooding in the area, reduced pressure on wastewater management system and established a more natural water cycle in the area. An additional benefit came from the increased moisture in the soil that also helps to ameliorate the Urban Heat Island effect in and around the park.
Case Study DescriptionChallenges
The park is characterised by steep slopes. This, in combination with compacted soils and considerable proportion of sealed surfaces in the park resulted in little infiltration of water into the ground, and intense water runoff and erosion during heavy rain events. The housing nearby was regularly affected by flooding, and the basements and ground floors were suffering from dampness, causing inconvenience and health hazard to local residents. In addition, the runoff carried a considerable amount of suspended matter that was a burden for the waste water management system in the city. Low rates of infiltration implied low moisture levels in the soil. As a consequence, the park area had difficulties in supporting substantial vegetation and thus was not providing as much cooling as possible during hot weather. The state of the park area had already caused problems for residents in terms of flooded buildings as a result of cloud bursts; leading to protests by inhabitants were the driver for including the improvement of the park’s drainage system in a programme of urban rehabilitation. Although not explicitly addressing increasing risks of cloud bursts and droughts under changing climate conditions, the solution adopted will contribute to improving the resilience of the residential area to heavy rainfall events and drought. In addition, increased infiltration capacity and the increased water availability for the park vegetation, as well as reduced surface run-off, will improve the microclimate, especially important during heat spells.
The aim of this initiative was to restore the natural water cycle in the urbanised area of Gomeznarro Park. The specific objectives were:
- Regeneration of the park landscape;
- Elimination or significant reduction of runoff processes;
- Reduction of the volume of water with high levels of suspended matter, whose quantity and quality affected the urban drainage system during heavy rain events;
- Demonstration of the efficiency of new water sensitive materials and rainwater management techniques.
The 10,000 square meters area of the Gomeznarro Park located in the southern part of Madrid, in Hortaleza District, underwent a transformation through application of a combination of grey and green infrastructure. The changes in the park included:
- Restructuring and/or replacement of the eroded and compacted soil;
- Removal of impervious pavements and their replacement with permeable surfaces, thereby facilitating water drainage and collection;
- Installation of underground storage tanks under the pavements and the associated water collection and distribution system;
- Re-vegetation of the eroded areas.
In 2004, the project received a ‘good practice’ qualification as part of the best practice award scheme by the UN Habitat. The water infiltration and collection technology has been subsequently replicated in a number of projects in Madrid (e.g. green areas in Valdebebas development; Madrid Rio - M-30 motorway; sports areas Daoiz y Velarde and Marques de Samaranch; Alzheimer Centre Fundación Reina Sofia) and elsewhere in Spain (e.g. the shopping centre car-park in Autonomous Community of Galicia and a park in Urbanización Torré Baró in Barcelona).Relevance
Case mainly developed and implemented because of other policy objectives, but with significant consideration of CCA aspects
The project was driven and funded by the Madrid municipality. The technology and consultancy for the intervention was provided by a private consultancy company. The park is surrounded by social housing built in the 1960s. Tenants’ complaints about the dampness in their houses caused by flash flooding provided an impulse for the housing association to refurbish the residential buildings. This process was integrated with the municipality’s plan and the revitalisation of the Gomeznarro Park.
The technology and materials applied were novel in Spain. This caused delays in implementation, as the design had to be carefully planned; approval criteria for the solutions proposed by the private consultant and provider of the technology had to be defined; and the contractors had to be thoroughly briefed. A particular difficulty arose as a result of the need to engage different municipal departments (water management, construction, planning, environment and others) in the planning and delivery. The drainage of urban green spaces approach adopted in this case study has been replicated in other locations in Madrid and elsewhere in Spain.
The municipality of Madrid financed the project. The construction cost was €343,600 (approximately € 34/m2). Whilst the benefits have not been assessed in monetary terms, there are no additional maintenance costs in comparison to traditional landscaping solutions used in parks. The project resulted in reduced erosion, risk of flooding and pressure on the drainage systems. The park receives yearly about 5 million litres of rain water, which now does not enter the drainage system but instead recharges the groundwater levels and results in a lower need for additional watering by park maintenance. Further benefits include improved air quality and reduced air temperatures in and around the park.
In 2002, the Municipality of Madrid introduced compulsory environmental impacts assessment for any urban transformation undertaken in the city (Ley 2/2002, De 19 de Junio, de Evaluación Ambiental de la Comunidad De Madrid), including the reduction of water consumption as one of the assessment criteria.
Following the completion of the project, a municipal by-law for efficient use of water was introduced (Ordenanza de Gestión y Uso Eficiente del Agua en la Ciudad de Madrid ANM 2006\50) which explicitly requires measures for reduction of water consumption and creation of water reserves in Madrid.
Planning: 3 months.
Realization: 3 months (January - March 2003).
The infrastructure is still in place and functioning. Provided that there is no damage to the underground water distribution and collection system, there is no lifespan limit for the solution.
Javier del Palacio Fernandez-Montes
Ayuntamiento de Madrid
Tel: +34 91 5887643