Good Landscaping for Water Quality

Landscaping Best Practices

There is plenty you can do right in your own yard to improve the water quality of water bodies around you.

Leaves

Leaves are your tree’s way of getting nutrients back into the soil. Hauling off leaves every year will slowly degrade your soil. Healthy soil acts like a sponge to absorb rainwater and reduce runoff on your property.

Mow leaves on your lawn and let them enrich your soil
Leave them in place as mulch in your flower beds
Extra leaves can be composted with kitchen scraps to use later
If you must dispose of them, never pile them in water ways. Unnaturally large amounts of leaves will alter water nutrients and harm aquatic life

Pile extra leaves near the street but NOT on impervious surfaces where rain could wash them into the storm drains.
- For guidance and schedule for leaf collection, see Leaf Collection. A Public Works crew will come to take the leaves to the wood recycling center to be composted.If you want free leaf compost, visit the City's Wood Recycling Center

Mulching Practices

Mulching can be very useful in retaining moisture in your soil and preventing unwanted vegetation (weeds), but reapplying mulch year after year should be avoided.

Reduce mulch zones and increase the area covered by plants
“Fluff” hardened mulch with a cultivator or rake to allow water to soak through to your plants. Do this also before applying new mulch so that you can reduce the amount needed
Do not use dyed mulch – The dye can be used to cover inconsistencies from varieties of treated and scrap wood, which can come from multiple sources that contain potentially harmful chemicals

Do not pile mulch against tree trunks or plant stems. This will increase the risk of fungal disease, inadequate oxygen, and strangeling adventitious roots
Mulch rings for new trees or shrubs should be wide, but not too deep (2'' or 3'' is a good rule of thumb).

Lawn and Mowing

There are more than 40 million acres of lawn in the US- making its area coverage three times larger than any other irrigated crop in the US! TN has 1,040,000 acres. Lawn care often requires lots of pesticides, herbicides and fertilizers, which can runoff and harm streams.

Reduce the amount of lawn on your property. Lawn does not infiltrate water into the ground as well as taller vegetation. Traditional turf lawn and any impervious surface like roofs or concrete will cause more rain water to “run-off” your property washing excess nutrients, sediment, and possible pesticides into the storm drain and then to the nearest creek or river

Do not mow too low. A lawn that has been mowed too closely will experience root die-off which will stress the grass more in drought times. Reduced root depth will also mean less rain water is soaked up by your lawn, leading to more stormwater runoff
Leave grass clippings on the lawn to decompose and enrich the soil

Erosion Prevention

Sediment is the most prevalent pollutant in Chattanooga. If water is washing off your property, is it clear or brown?

What is erosion? Bare spots where soil is exposed because there is no vegetation cover. Avoid clearing steep slopes whenever possible. Destabilizing slopes can be a danger to your property or even personal safety. Reinforce slopes or banks with native vegetation

Stream Buffers

If you have a waterway in your yard, are the banks bare, sheer, or overhanging the water? These are all signs of erosion, which leads to poor water quality.

What is a buffer? In a natural setting, creeks and streams have a variety of plant life growing on the banks. Trees, shrubs, grasses, sedges, & ground cover all work to keep the creek banks stabilized with their root systems. This is called a buffer zone. Buffers are the last line of defense for the health of aquatic ecosystems. They filter surface runoff before it gets into the waterway

When stockpiling bulk soil, compost, or mulch choose a spot for your pile where rain cannot wash these materials onto roads or storm drains. Surround these materials with silt fencing or straw bales if there is a potential for this to happen.

Designing Landscapes for Water Quality

Native plants are great for water quality and wildlife:

Plants that are native to TN or this region are better suited to this climate and the local soils. This helps you spend less money on fertilizers, pesticides, and water bills. After an establishment year, you may not need to water new plants at all
Design for less impervious surface by asking yourself if the same service/function canbe accomplished with previous alternatives

Think about where the water will go when it rains
Design for as little “mulch zone” as possible. Allow plants to fill in the planting area.
Dense, tall vegetation is best for intercepting rainwater and infiltrating it into the soil

Chemical Treatment

Herbicides & Pesticides – While commonly used, herbicides & pesticides are detrimental to water quality. Residues lingering in the soil can be washed into waterways.

Follow the instructions on the label. These directions have been authorized by the EPA for your safety as well as environmental protection
Generally, herbicides should not be applied when a rain event is predicted within 24 hours

Consider the "cut-stump method" instead of foliar spray when removing exotic invasives. This will reduce non-target impact and the volume of chemical needed to treat each plant
Consider mechanical/hand removal to avoid using chemicals at all. Specialized tools exist to considerably help in these instances

Fertilizers

Nutrients are important for plant growth, but too many of them can be a problem.

Fertilizers are a form of nutrients and when they wash off into water bodies they can cause a buildup of phosphorus and nitrogen. These are nutrients that algae feed on and when they are found in excess” with “and cause algal blooms when found in excess. Algal blooms can release toxins, block out the sun, and smell bad. When they die, bacteria start to decompose them, which uses up oxygen in the water needed by aquatic life to survive. This process is called Eutrophication

Incorporate fertilizers into the soil so they do not wash off in a storm

Rain Gardens

Rain gardens are a landscaping features that help reduce stormwater runoff and support native wildlife and insect species by using native plants.

Rain gardens are great way you can reduce excess runoff coming from your roof
Thinking of installing a rain garden on your property? The City's Stormwater Division has a residential reimbursement program called RainSmart, that may be able to help!Visit the RainSmart page for more info

Watering

Native plants are a more water efficient choice. After they are established, they require either significantly less, or no watering at all because they are adapted to the local climate.

If you need to water, try to do so in the mornings, or at the least hot time of day
Bare soils dry out quickly, often making it difficult for water to really soak in during those short summer showers. Try to keep soil healthy and fluffy, so that it can absorb rain like a sponge. More plants are best, but mulch can also help soils retain moisture by shading out the sun and acting as insulation for the soil

Rain barrels are a great way you can reduce excess run-off coming off your property while collecting free water for non-potable jobs. This water can be used to water your garden or just drained off slowly in preparation for the next rain event. The City’s Stormwater Division is now offering reimbursement for approved rain barrels! Visit our Rain Smart Rain Barrels page for more information

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