Louisiana Yards and Neighborhoods

Reduce Stormwater Runoff

www.lsuagcenter.com/lyn

Reduce Stormwater Runoff

• Stormwater runoff– Definition – Problems – Solutions

• Best Management Practices (BMPs)

– Prevent runoff – Vegetative cover

• Alternatives • Groundcovers

– Reduce pollutants – Fertilizer – Pesticides

Hydrologic Cycle• Water on earth is constantly recycled• Components of water cycle:

– Soil Infiltration– Evaporation– Transpiration - the process by which plants release water into the atmosphere– Surface and channel storage– Groundwater storage

The soil matrix filters and somewhat detoxifies impurities from water as it travels through the ground.

UrbanizationIntensity of land useAmount of impervious surfacesWater quality degradation

Nonpoint source pollution Sources of pollution that cannot be pinpointed to any single cause. Usually associated with trash, car oil, chemical lawn products and other residues that are easily carried away by flowing water.

Stormwater Runoff - Rainwater that flows off yards, roads and parking lots, carrying

pollutants into our waterways.

According to the EPA, polluted runoff is the #1 water quality issue in Louisiana

Nutrients Toxins Sediments

Thermal Stress Debris

Pathogens Photo courtesy of NEMO

Stormwater ContaminantsMetals

zinc, cadmium, copper, chromium, arsenic, lead

Organic chemicals pesticides, oil, gasoline, greasePathogen viruses, bacteria, protozoa

Biochemical oxygen demand (BOD)

grass clippings, fallen leaves,human and animal waste

Sediment sand, silt and other particlesSalts sodium chloride, calcium chlorideNutrients nitrogen, phosphorus

The Problem• Increased volume of surface runoff

• Increased velocity of surface runoff

• Concentration of pollutants in runoff

Erosion

Sedimentatio

n

Flooding

Lowered

water

quality

Elevated nutrients can cause:Elevated nutrients can cause:– Polluted drinking water Polluted drinking water – Excessive aquatic plant growthExcessive aquatic plant growth– Lower dissolved oxygen levelsLower dissolved oxygen levels– Fish killsFish kills

The Solution• Use practices or methods to prevent,

reduce, retard or remove stormwater runoff contaminants before reaching receiving waters.

• Best Management Practices (BMPs) are a series of direct recommendations based on research, evaluation and educated assumptions.

Be Louisiana FriendlyRegardless of the type of property you own, you can help preserve Louisiana’s natural resources by:

1) Preventing runoff2) Increasing vegetative cover3) Reducing pollutants

Keep rain and irrigation water on your property and

out of storm drains.

Prevent Runoff

Factors Affecting Stormwater Runoff:• Rainfall intensity, flow rate, season• % impervious surfaces• Watershed size, slope• Soil type, soil compaction• Type of vegetation• Density of vegetation

Within our control Not within our control

Minimize Runoff by Using Pervious Surfaces…

for walkways, patios and driveways

Direct Downspouts and Gutters Toward Porous Areas

If downspouts drain to planted areas, be sure to select plants adapted to periodic

flooding.

Collect Rain Water

Use a rain barrel or a cistern to collect and store runoff for irrigation purposes.

Cistern

• Water during early morning hours.– Plants are already wet.– Less evaporation losses.

• Water less frequently in cooler months.

• Water “as needed,” not routinely.• Do not irrigate if rain is expected.

Plan Irrigation Schedules According to the Weather

Earth ShapingIf your property is sloped, you may want to make minor grade changes to divert runoff. This can be accomplished with terraces.

Terracing can be an attractive design

element in your yard.

Berms and SwalesCreating swales (low areas) and berms (raised earthen areas) will help to catch, hold and filter storm water. Elevations and depressions as small as 3-6 inches can make a huge difference.

Vegetative CoverVegetative CoverPlanting groundcovers on slopes is an excellent way to:• Catch and filter storm water.• Slow the velocity of water movement.• Reduce erosion.

Turf grass is a versatile groundcover that is effective at filtering

nutrients.

• Attractive• Insulates the soil• Acts as a living mulch that

helps build up humus levels in the soil

• Provides habitat and cover for beneficial insects and other predators

Covering the Ground With a Carpet of Vegetation Has Other

Advantages

Blanketflower Gaillardia pulchella

Disadvantages• If the ground cover is too

vigorous, it may require containment.

• It can compete with other plants for water and nutrients.

The following factors should also be taken into account, when choosing the

right plant for the right place…

Sweet potato Ipomea batatas ‘Margarita’

Select Plants Based on Site Conditions

• Acid, alkaline - (test your soil’s pH)• Dry, moist• Full sun, shade• Heat, cold• Salt• Space• Obstructions

Periwinkle Catharanthus roseus

‘Diva’

Alternative GroundcoversAlternative GroundcoversFor Shaded Areas

Lilyturf Liriope muscari (USDA Zone 6-11)

Periwinkle Vinca major (USDA Zone 8-11)

Cast Iron Plant Aspidistra elatior (USDA Zone 8-11)

Beach Sunflower Helianthus debilis (USDA Zone 8B-11)

Alternative GroundcoversAlternative Groundcovers

Clover Trifolium repens (USDA Zone 5-11)

Perennial Peanut Arachis glabrata (USDA Zone 8-11)

Alternative GroundcoversAlternative Groundcovers

Junipers (USDA Zone 8-

11) Juniperus spp.

For Sunny Areas

Asiatic Jasmine (USDA Zone 8-11) Trachelospermum asiaticum

Tree CanopyTree CanopyIncorporate trees in the landscape

– Intercept rainfall– Reduce soil compaction, thus improving

water infiltration into soil– Increase the property

value– Energy efficient way

to cool the home

Reduce Pollutants

• Sweep grass and soil back onto lawns.

• Sweep up any fertilizer on impervious surfaces.

• Remove trash.• Clean up oil spills and

leaks with cat litter.• Pick up after pets.

Because water can wash off our yards, it is important to reduce the amount of

pollutants on our property.

It is unrealistic, even unwise, to strive for an insect, disease and weed-free yard. Instead:

• Learn to identify key pests associated with the plants in your yard.

• Check plants regularly for signs of pest problems.

• Determine what amount of damage warrants action.

Manage Yard Pests Responsibly

• Avoid routine applications of pesticides.

• Choose the least harmful method of control.

• Treat only affected area rather than spraying the entire yard.

Fertilize Appropriately

• Follow printed instructions carefully!

• Do not apply fertilizer or pesticides before a heavy rainstorm.

If applied improperly, excess fertilizers can run off our yards into waterways or leach

into groundwater.

Louisiana Yards and Neighborhoods

Reduce Stormwater Runoff

www.lsuagcenter.com/lyn