Managing Water in Landscape and Hardscape Design
Help support New York State's natural resources while enhancing your environment by responsibly maintaining sustainable landscapes. See also the full EO 4 specification for Sustainable Landscaping.
In a natural water cycle, rainfall is intercepted by the tree canopy and other vegetation before eventually making its way to the ground where it penetrates the earth and is filtered by the soil. Thus cleansed of impurities, it recharges the groundwater and is taken up by plants that will return the water to the atmosphere to condense and fall as precipitation once again. Supporting this natural cycle helps to sustain an adequate supply of clean drinking water.
Development and hardscape disrupt the natural water cycle by preventing rainfall from reaching the earth. Instead, it may be collected by a sewer system that conveys it to a treatment facility, where if it exceeds the capacity, may cause raw sewage to be released, untreated. If stormwater is not absorbed by the ground, it runs over the surface, carrying contaminants directly to nearby ponds, lakes, streams, and rivers. Stormwater runoff is a major contributor to non-point source pollution.
The following strategies help to preserve water on the landscape and avoid stormwater runoff:
Use Green Infrastructure - Green Infrastructure (GI) recognizes the critical utilitarian value of the functions of natural systems and uses it strategically. At the landscape level, GI includes forests, grasslands, and wetlands. At the site level GI is street trees, vegetated swales, green roofs, rain gardens, permeable pavement, and other practices typically engineered to help manage stormwater.
Prioritize Natural Stormwater Penetration - Maximize stormwater ground penetration in the following prioritization:
- Diverse Native Plant Communities: The varied strata of leaf canopy of trees, shrubs, and herbaceous plants in natural plant communities intercept rainfall, enabling it to penetrate into the soil over time.
- Turf: This is the most commonly used groundcover, however, while turf allows penetration of rainfall, lacking canopy strata, it does not significantly intercept it, and excess rainfall easily runs over the ground to surface water bodies. Also, mowing equipment is a significant source of air and water pollution. Other low-growing, native groundcovers that provide greater interception and require less maintenance should be considered.
- Permeable Paving: Permeable paving allows rainfall to penetrate into the ground beneath it where natural filtering occurs and groundwater is recharged. This reduces run-off and the volume of stormwater to be managed.
- Non-Permeable Paving: Concrete and asphalt pavement do not allow rainfall to penetrate necessitating a system for stormwater collection and treatment. As paving prohibits the existence of natural systems and the life-supporting benefits they provide, it should be limited and replaced with permeable paving wherever possible.
Protect Streamside (Riparian) Buffers - Buffers of natural vegetation should be maintained along rivers and streams and around lakes and ponds to intercept stormwater and slow its entry into water bodies. Vegetated buffers also help prevent contaminants from reaching water bodies.
Reduce Watering - Reduce having to water or irrigate a landscape by using plants that are adapted to site conditions.
Anticipate Extreme Weather - Every site has unique susceptibilities in the event of extreme weather events and natural disasters. Landscaping that anticipates these events, like leaving floodplains undeveloped and giving streams room to meander will both help to avoid catastrophe and mitigate any damage done.
Soil - At the Root of Everything
Reduce Compaction - Soil compaction restricts rainfall penetration and reduces the aeration needed by plant roots. As trees are a particular concern, care should be taken to protect an area the diameter of the crown from vehicle or excessive foot travel.
Prevent Erosion - Any soil disturbance increases the likelihood that it will be carried overland, causing sedimentation into surface waterbodies. Take measures to keep soil onsite, particularly during construction.
General Landscape Maintenance
Reduce Turf Areas - A simple way to accomplish varied goals of an environmentally friendly landscape, while saving time, work, and money is to re-evaluate sites and reduce the area maintained as turf, allowing native plant communities to re-establish. This will benefit pollinators and other wildlife, and reduce the emissions from mowers that impact air quality as well as reducing noise.
Reduce Chemicals (& Save Money) - Pesticides and fertilizers are expensive, can be harmful to water quality and may be toxic to wildlife. Using plants that are adapted to the site - preferably native and definitely non-invasive - should eliminate the need for pesticides and fertilizers, except in rare cases. In cases where a chemical application is necessary, be sure to follow the instructions on the product label.
Plant Trees to Moderate Temperature - Strategically maintaining or planting trees to shade structures can reduce air conditioning costs. As windbreaks, trees also can reduce heating costs.
Support Local Pollinators - Plant native herbaceous plants preferred by pollinators in areas with access to other habitat requirements of water and bare soil to construct hives and nests.
Support New York State's Biodiversity
Prioritize Native Plants - Native plants are preferred, but where sites are so compromised they would no longer support native plants (e.g. where road salt is a factor) non-native plants may have to be used. Invasive plants must never be planted and should be controlled as much as possible where they naturally occur.
Showcase New York State Ecosystems - Landscaping with native plants educates residents and travelers alike about what makes New York unique.
Use Sustainable Landscape Design to Enhance the Greater Natural Landscape - Plant selection and strategic planning on a site can help to support the regional ecology. Landscaping can bridge developed areas to create connections between hubs of natural areas.
Public Awareness and Education
Install Signs and Labels - Not all aspects of sustainable landscaping will be immediately understood or appreciated by the general public. Deliberately allowing native plant communities to regrow in places previously maintained as lawn may be perceived as neglect. This is not neglect - it is by design! Labels that identify species and signs that explain the benefits of sustainable landscaping will help in the transition.
Work With Nature, Not Against It - Our culture evolved to value landscaping according to the money, time, work, and chemicals to maintain it in an un-natural state. This apparently demonstrated that the land was being "responsibly cared for." Unfortunately, this mindset has had many negative impacts that would be reduced or eliminated if we worked with nature rather than against it.