Designing Sustainable Landscapes in Hot and Dry Climates: How and What to Consider?

Article by Giacomo Guzzon We explore designing sustainable landscapes in hot and dry climates by taking a closer look at the Lake Garden by Iúri Chagas, in Olhão, Algarve, Portugal Since I am a landscape architect who works and lives in London, you wouldn’t expect that I often deal with schemes that have to withstand drought and prolonged periods of heat, but the reality is that London is getting hotter and dryer, and in the UK there is an increasing need for water-wise and sustainable design. Analysing projects facing such problems is crucial for every designer who intends to create landscapes that are both visually appealing and sustainable. Every landscape architect should be familiar with sustainable interventions that are universal, regardless of the climate he or she is working in.

Designing Sustainable Landscapes

The Lake Garden in southern Portugal illustrates some important sustainable design interventions. Designed by landscape architect Iuri Chagas, the Lake Garden covers 900 square metres in the Algarve, an area that gets more than 3000 hours of sun per year and with an average rainfall of only 500 mm per year.

Meticulous Choice of Native and Drought-Tolerant Species

Designing planting schemes in a dry and hot climate is surely more challenging than working in a mild cool environment where basically everything thrives. In such arid Portuguese locations, the rule to follow pretty strictly is ‘the right plant for the right place’ because otherwise there is little chance that the planting will be successful. Native plants are the most adapted to the climatic and edaphic conditions of an area and therefore should be prioritized, but often there is a need to enrich a scheme with species that are not native but equally tough and which possess special characteristics.

Using Mediterranean Species

In the Lake Garden the bulk of the plants is native and reflects typical Mediterranean species such as Olea europaea (olive), Prunus dulcis (almond) and very common shrubs, like Arbutus unedo, Myrtus communis, Viburnus tinus, Nerium oleander, Lavandula and Rosmarinus offinalis. Nevertheless, the designer also included, among native species, some exotic grasses and perennials to add drama and give the garden a more ornamental and dynamic look. He included, in particular, ornamental grasses to add movement to the planting, such as Pennisteum ‘Rubrum’, Stipa tenuissima, Festuca glauca and perennials like Phormium tenax.

Working with Local Materials

Considering that the Algarve region’s topography is hilly and the geology rocky, I would expect a lot of local rocks in the garden. The Algarve coast is famous for its picturesque limestone cliffs, a material widely used in the Lake Garden.

Here the designer opted to use this local material as mulch and to frame the ponds and streams that will inevitably feel more a part of the wider landscape archetype. Actually, the buff colour of the stone blends very well with the colours of the Algarve’s dry landscape. The stone feels right because it was sourced locally, which adds the benefits of minimizing the cost, helping the local industry, and being environmentally sustainable. Trying to use local materials and visiting regional quarries is very important for landscape architects in order to better familiarize themselves with the material peculiarities of the region and, more importantly, providing projects that are ethically sensitive.

Using Water as a Means of Habitat Creation

This garden has several ponds that follow the sloping topography of the site and are connected by a stream which meanders through the garden and encloses areas of lawn and planting. Using water in a landscape that is actually dry seems at first glance a controversial decision, but if you consider the amount of habitat that a simple pond could create for the local fauna, then the decision to use water seems an environmentally sound one. Water bodies in this garden not only convey a ‘refreshing’ illusion to its users, especially in this hot location, but more importantly, they attract many wildlife species. All ponds’ banks in this garden are gently sloped with rocks and vegetation, creating the ideal conditions for insects, spiders, amphibians, reptiles and small mammals to easily access the water. The banks were covered with pebbles from the Algarve rivers, which helps to create riverside conditions similar to those found in the area.

Horticultural Practices

Since water is very limited in the area, every horticultural practice is aimed to save it and to keep the soil moist as long as possible. The designer decided to mulch all flower beds with gravel from the region. The gravel layer keeps the soil moist and inhibits weeds growth.

Moreover, since smaller plants establish better than large container-grown plants, all plants were planted when small. In this way plants will adapt better to the environment and this will also minimize the cost for planting. Irrigating is necessary for establishing all plants, even if they were selected according to their low water requirement. To encourage plants to root deeply, it is best to water infrequently but heavily because if plants get water very often they will root close to the surface, becoming weaker and more dependent on irrigation. Creating resilient landscapes that are able to cope with a more extreme and unpredictable weather pattern is a challenge that every landscape architect will have to face. Being able to design within these complicated situations is necessary for professionals and it requires a deep understanding of the wider landscape archetype where the project is located. The topics above are only a starting point to reflect on how important it is to choose local materials but also on how small interventions and horticultural practices can make a scheme work in a hot and arid environment. The Lake Garden shows us how a simple but thought-out design can achieve a lot for the environment, while creating an enjoyable place for its owners. What do you think could have been done to make this project even more beneficial for the environment and wildlife?

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Full Project Credits For Lake Garden :

Project: Lake Garden Designer: Iúri Chagas Location: Olhão, Algarve (Portugal) Size: 900sq/m Completion Date: 2015 Client: Private Landscape Contractors: Jardimgarve Recommended Reading:

• Becoming an Urban Planner: A Guide to Careers in Planning and Urban Design by Michael Bayer
• Sustainable Urbanism: Urban Design With Nature by Douglas Farrs

Article by Giacomo Guzzon

Published in Blog