Your guide to managing water

Every development must respond to environmental conditions but the value that ecologically informed landscape can bring is rarely embraced. Landscape design is too often seen as a beautifying function, not an essential resource to harness the opportunities of sustainable infrastructure.

Sustainable infrastructure

Landscapes and the green infrastructure of our towns, suburbs and near-urban areas can deliver massive benefits and serve many functions: water collection, recycling and reuse; amelioration of microclimates for all living organisms and the reduced energy consumption of buildings; energy and resource efficiency, including the use of recycled materials, low embodied energy materials and on-site renewable energy production; the protection and the creation of habitat to enhance biodiversity; opportunities for local food production; the creation of a sense of place and community; and promotion of human health and well-being.

This article is a practical guide to some of the solutions available for the practical management of water.

SUDS

SUDS or sustainable urban drainage systems provide flexible, long-term solutions for the control of surface water.

SUDS must take account of the quantity and quality of run-off and deal with it close to where rain falls. They must harness the amenity value of surface water in the urban environment, manage potential pollution at source, and protect water resources from pollution (such as accidental spills) and other sources. Importantly, they can also provide a habitat for wildlife and encourage natural groundwater recharge.

SUDS can be used in soft landscapes and hard surfaced areas, in areas of no or little infiltration, on brownfield and contaminated sites and where space is limited. They can also potentially enable new development in areas where existing sewerage systems are close to full capacity. They can cost the same or less than existing urban drainage systems, which may cause flooding, pollution or other damage to the environment.

The design of SUDS involves selecting the best options against the associated risks. The development area is sub-divided based on different drainage characteristics and land uses and will incorporate a range of components from swales and filter strips to large-scale basins or ponds.

Swales and filter strips

Swales and filter strips, ideal for high-risk areas, are vegetated depressions which lead surface water over impermeable land. They typically use the green space of a roadside margin and convey water from the drained surface to storage or discharge systems.

Landscape architects are not post-hoc embellishers of development. They have a major role to play in sustainable masterplanning

Both can be used to replace or reduce the need for conventional roadside kerbs, saving construction and maintenance costs. By mimicking natural drainage patterns, they allow rainwater to run through vegetation, which acts to slow its force and filter pollutants.

Compared to a conventional ditch, a swale is shallow and relatively wide, providing temporary storage, conveyance, treatment, the possibility of infiltration and the ability to increase the wildlife value by creating new habitats. Filter strips, because they are gently sloping areas of ground, only attenuate the flow slightly but can be used to lessen the impermeable area.

Importantly, swales and filter strips are natural, cost-effective and multi-functional solutions that require little maintenance or management.

Basins and ponds

Basins and ponds act as a contingency component to prevent flooding and pollution in higher risk areas by storing run-off in wetter periods of the year. They allow for extended natural treatment of the run-off.

Basin structures include flood plains and basins, usually a vegetated depression, which vary from those that are dry for most of the year except after storm events to those where all collected run-off is stored to allow time for natural processes to remove pollutants.

Ponds, on the other hand, always contain water in dry weather but are designed for additional capacity. These include balancing ponds which attenuate flows by storing runoff during the peak flow and release it at a controlled rate, flood storage reservoirs, lagoons, retention ponds and wetlands. Each has its own benefits.

The different types of ponds and basins can be mixed to enable permanently wet areas for wildlife, to provide opportunities for leisure, sports and recreation, and to deliver public spaces that reflect and marry the different natural elements while having a functional purpose. managing risk

The common fear when introducing basins, ponds and swales, is the risk that they pose to health and safety, particularly drowning or overturning vehicles. A good landscape architect will manage these risks, creating ponds with shallow side slopes or shelving edges and incorporating barrier vegetation.

the value of landscape Ecologically informed landscape architecture provides a sustainable infrastructure that exploits every component of a regeneration scheme for the benefit of the environment, the community and the long-term viability of the scheme. Landscape architects are not “post-hoc embellishers of developments”; they have a major role to play in sustainable masterplanning that starts with integrated green infrastructure.