Naturalizing the yard increases its water absorption capacity and reduces rainfall runoff. It also improves the quality of the runoff water. Tree and shrub leaves and stems break the force of the rainfall on the soil; their roots hold soil in place and absorb nitrate and phosphate fertilizers. Mulch also breaks the force of the rain; it also keeps root plants moist. Porous paving has holes which allow rain falling on driveways, walkways and patios to soak into the ground. A rain garden is a planted shallow landscaped depression which functions as a ground water recharge area. A cistern harvests water from a home roof for irrigation which might otherwise runoff into the street.
The result of these improvements is a large reduction in rainfall runoff. Before landscape naturalization, the rainfall runoff was 180,000 gallons per year; this is two-thirds of the total 270,000 gallons per year rainfall. After landscape naturalization, the total was only 67,500 gallons/year or 25% of the rainfall total.
With a lawn in front of our home we are kings and queens of our castle. We harken back to old English manor houses surrounded by sheep-cropped grass and specimen oaks.
A lawn is a wonderful surface on which to rest, play or party—very useful. But too much lawn area has a shadow side.
The fertilizers and pesticides, used to maintain lush lawns, are washed off by rain and end up as pollution in local waters. Lawn watering puts severe strain on water supply. Lawns have a limited capacity to absorb rainwater and contribute to flooding. They take a high degree of maintenance.
Ground covers and shrubs are practical alternatives to lawns. The use of native and low-water species can minimize fertilizer and pesticide use. Mulch in non-lawn areas keeps down weeds, conserves water, and is attractive in appearance.
Lawns should be fertilized with compost or a small amount of slow release fertilizer. Overwatering should be avoided, and pests controlled with eco-friendly methods.
Like in all things moderation is key. Plant as much lawn as you need for outdoor activity, and the rest in trees, shrubs, and edible landscapes. Maintain what lawn you do have with best practices.
A cistern is a rain storage tank. Most cisterns are fed from roof-runoff collected by means of gutters and downspouts. A one-inch rain, falling on a 2,000 square foot-roof would yield 1,200 gallons of runoff.
Most cisterns installed in homes are placed above ground and hold 1,000 to 2,500 gallons. Some cisterns may be 10,000 gallons or more; these are usually placed underground.
Cisterns are usually constructed of fiberglass, concrete, or metal and have a few accessories to improve its function. It is common to have a device which diverts the first few flush of runoff, to minimize the amount of roof debris entering the cistern. In addition, the water is filtered before entering the cistern. Another device diverts water when the cistern is full.
Water is withdrawn from a cistern by gravity by means of a hose near the bottom of the cistern, or by a pump. Cistern water is commonly used for yard irrigation.
A cistern has a double benefit. It conserves water and reduces the amount of yard runoff. For a 2,500 gallon cistern, Sarasota County provides an approximately 11% reduction in storm water assessment.
A 2,500-gallon cistern in Sarasota, Florida (54 inches annual rainfall) could collect 20,000 gallons annually of useable irrigation water. This would be 20% of the annual outdoor usage of 100,000 gallons.
A lower cost DIY option is a rain barrel. If you have gutters on your house, you may be able to collect 55 gallons of water during a ½ inch rain by directing a downspout to a rain barrel.
Trees and shrubs multi-task in a home landscape. They prevent erosion by holding soil and breaking the force of the rain. Falling leaves and twigs mulch the soil, protecting it from scalding sun and rain. These functions improve runoff water quality and reduce the strain on drainage facilities.
Long-lived trees and shrubs are an important element of a low maintenance, Florida Friendly landscape. Native and drought tolerant types reduce irrigation demand.
Shade trees are especially valuable to shield east-and west-facing windows from direct hot summer sun. They can prevent rooms from overheating and reduce your conditioning bill. They also keep your yard and patio air temperatures cooler, while adding to our homes attractiveness.
A home orchard can produce hundreds of pounds of fruit annually. And in doing so, provide hours of bliss for the proud home hobbyist.
The hard surfaces of sidewalks, patios, driveways and roads are the bane of urban water management. Rain, hitting these surfaces, rushes in polluted torrents to the nearest storm drain or water body.
Porous paving was developed to solve this problem. It has the marvelous capacity to support foot or car traffic, and drain water.
The simplest porous paving is crushed rock useful in low traffic areas. In “porous turf” systems, used in parking lots, grass grows in a supporting plastic grid system.
Three of the most common permeable pavements are: interlocking concrete pavers: concrete grid pavers, and permeable concrete. Interlocking concrete grid pavers drain in spaces between the blocks. Concrete grid pavers drain through holes in the grid, and through the porous concrete blocks themselves. Porous concrete uses only coarse sand, allowing the formation of interconnected drainage holes during curing.
Field tests of various porous paving systems have shown they can reduce runoff by acting like a sponge. For example, one field study showed that interlocking concrete pavers could absorb 2.5 inches of rain in an hour. Concrete grid pavers and porous concrete could absorb water in the range rate of 1.0 to 1.5 inches per hour. (ref:
North Carolina State University Permeable Pavement Research).
A rain garden captures storm runoff and allows it to slowly seep into the ground. During a rain storm, a rain garden transforms into a shallow, temporary pond. A sand and gravel bottom allows the water to drain into local groundwater within 1 to 2 days. Bio-swales are broad shallow-sloped ditches which serve the same function.
Rain garden/bio-swales are frequently planted with hardy native plants able to tolerate extremes of moisture. Providing a beautiful landscape accent, they attract butterflies, birds and other wildlife. They also recharge groundwater and reduce the need irrigation for nearby plants.
Rain gardens/bio-swales restore the natural balance of a watershed, which has been lost in the process of urban development. They decrease urban flooding and soil erosion and scrub pollutants from urban runoff.
The slow drainage of water through sand, gravel and soil clarifies the water by removing soil particles and leaves. Soil microbes can even convert car oils to harmless water and carbon dioxide. Plants growing in or near the rain garden/bio-swale purify the water by removing nitrates and phosphates which can cause green “scum’ of algae on local lakes and bays.
A 250 square foot (e.g.,10 foot long by 25 feet wide) rain garden, with an average depth of two feet can capture the drainage of a one-inch rain over 6,000 square feet of roof, sidewalk, patio, or driveway surface.
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