Stormwater

What is stormwater?
Stormwater is water from rain or melting snow that does not soak into the ground. It flows from rooftops, over paved areas and bare soil, and through sloped lawns. As it flows, it collects and transports soil, pet manure, salt, pesticides, fertilizer, oil and grease, leaves, litter and other potential pollutants. A garden hose can supply enough water to transport pollutants toward streams, wetlands, lakes and oceans.

Storm water flows via storm drains and sewers from urban and rural neighborhoods into the nearest body of water. Some  storm sewers do not carry storm water to wastewater treatment plants in some communities but may be combined with storm drains in some older communities.

Why should you be concerned?
Polluted storm water degrades our lakes, wetlands and rivers. Soil clouds water and degrades habitat for fish and water plants. Nutrients such as phosphorus and nitrogen promote the growth of algae, which impact food production for aquatic life. Toxic chemicals, such as antifreeze and oil from leaking cars, excess pesticides, and zinc from galvanized metal gutters and down spouts are additional hazards that threat water bodies and the  health of fish and other aquatic life. Bacteria and parasites from pet manure can make nearby lakes and bays unsafe for wading and swimming after storms.

Storm water can also be a problem in homes. It can flow into basements and cause damage that is difficult and costly to clean up. Storm water can also flow down poorly sealed well shafts and contaminate drinking water. In areas with very porous soils or geology, pollutants in runoff may reach groundwater.

Public officials are focusing pollution control efforts on storm water management in urban and rural areas. Storm water pollution cannot be treated in the same way as water pollution from discharge pipes because it comes from many sources.

Keeping Debris out of Stormwaters

What can you do?

Where does storm water go? The next time you are home during a rain shower, head outdoors with your boots and umbrella and watch where the rainwater goes.  On a sketch of your property, draw arrows showing the direction that storm water flows off driveways, rooftops, sidewalks, and yards.  Does water soak into the ground quickly, or does it puddle in places and flow off lawns and driveways?  Your soil type affects water infiltration (soaking into the ground).  As you might expect, water infiltrates sandy soil quickly but has a hard time seeping into fine-grained silt or clay soils.

Note how far it is to the nearest storm sewer, ditch, wetland, stream or body of open water. Note whether runoff flows onto your land from adjacent streets, lands or storm water systems. If you live at or near the bottom of a hill, you may have special problems. Be sure to go out during more than one rain shower to get a good understanding of runoff flow during small and large storms.

• Oil stains, outdoor spills of antifreeze, brake fluid, and other automotive fluids are easily carried away by a rainstorm. Use pans, carpet scraps or matting to catch drips. Routine maintenance can prevent your car from leaking and help identify potential leaks. If you change your own oil, be careful to avoid spills and collect waste oil for recycling.
• Oily car parts and fluid containers should be stored where rain and runoff cannot reach them. Never dump used oil, antifreeze, or gasoline down a storm drain, in a ditch, or on the ground. These wastes will end up in a nearby lake or stream, or they may pollute your drinking water.
• Washing a car in the driveway creates runoff without the help of a rainstorm — a hose provides plenty of water. The dirty, soapy runoff drains directly into storm sewers, picking up oil and other pollutants as it goes. Wash your car on the lawn use commercial car wash or spray booth that sends its dirty water to a wastewater treatment plant.
• Most households store lawn and garden products like weed killers, insect killers and fertilizers. If storm water or floodwater reaches these products, it can transport them into surface water and possibly a well.
• Pool chemicals, salt for water softeners, and a wide variety of other chemical products can pollute water if they are washed away.
• Keeping such products in waterproof containers and storing them on higher levels and out of the potential path of runoff or floods is important. Avoid storage problems by buying only what you need for a particular task and then using up the product.
• Prevent the freezing of liquid products. Most pesticides, and some fertilizers, are liquid and may be subject to freezing. This may burst containers or render the product unusable.

Adapted from: Home-A-Syst publication EQM102, April 15, 2001, Fact Sheet 2: "How to Manage and Control Storm Water Runoff," Missouri Farm-A-Syst/Home-A-Syst Program, 205 Agricultural Engineering Building, University of Missouri-Columbia, Columbia, MO 65211

Urban Land Use

General
Runoff from construction sites – for example, highways, shopping centers, office buildings, new homes - is the major source of sediment in urban areas under development. There are two main reasons why construction activities increase pollutant loads in runoff, the volume and rate of runoff typically increase, providing a larger capacity to transport pollutants to rivers and lakes, and the vegetation is removed, leaving bare soil that is much more vulnerable to erosion.

Typical sediment loading rates from construction sites vary from 100 to 200 tons per acre per year and can range upwards to 1,100 tons per acre per year. By comparison, for farmland to maintain its productive capacity, erosion should be limited to no more than 1 to 5 tons/acre/year, depending on soil type.

Raindrop impact is the major cause of soil particle detachment, which can result in particles moving down slope in flowing water - known as sheet erosion - during a rainfall event. Flowing water can also detach soil particles if the velocity is high enough, usually where water starts to concentrate. If the velocity is reduced sufficiently, particles will settle out. The velocity at which settling begins is dependent on particle size and density, as is the time required for the particles to settle out. Large, dense particles, such as grains of sand, settle first. Fine clays settle out slowly and only in relatively still water.

Erosion control measures can disrupt the phases of erosion by making soil more stable, by managing runoff, and by sediment control. By preventing splash and sheet and rill erosion, soil stabilization measures, such as soil amendments, vegetation, and mulch, can interrupt the first phase of the erosion cycle, the detachment of soil particles. Vegetative cover can provide effective soil stabilization, but sometimes the vegetation needs the extra stability and protection of additional measures, such as erosion control blankets, silt fences, terraces, and diversions.

Erosion - and sediment-control structures should be installed and maintained in accordance with local jurisdictions, manufacturers' specifications or engineering drawings:

• Vegetative cover: Vegetative cover is the most effective and practical control of erosion and sediment loadings but it takes time for establishment. Sodding can reduce the time required for grass establishment and can be used to control erosion in some channels in lieu of riprap or concrete. The roots of vegetation, such as grass, bind soil particles together to resist erosion and vegetation helps absorb the impact of raindrops to prevent detachment of soil particles.
• Mulch: Natural mulch, such as straw and wood chips, and artificial mulch, such as fabric blankets, are effective in absorbing raindrop impact to reduce soil detachment and are effective as soon as they are applied. Mulch is normally used in combination with seeding to provide ground cover during the establishment period for a temporary or permanent vegetative cover. A disadvantage of a strawlike mulch is that it can blow or wash away.
• Soil amendments: Polymer soil amendments known as polyacrylamides (PAM) can help bind soil particles together to reduce erosion and sedimentation. Polyacrylamides are not a cure-all, but they can be a good addition to other sound management practices.
• Silt fence barriers: A silt fence is a temporary barrier of fabric used to intercept sediment-laden runoff from small drainage areas. A silt fence can be used to promote sheet flow, to reduce runoff velocity, and to help retain transported sediment on the site, thus reducing erosion and enhancing water quality. Silt fences are usually installed on the contour with each end turned upslope, causing the runoff to form a pond.
• Straw bale barriers: A straw bale barrier is a temporary entrenched and anchored barrier used to intercept sediment-laden runoff and to provide some retention of sediment from small drainage areas. A straw bale barrier can be used to promote sheet flow and to reduce runoff velocity, thus reducing erosion and improving water quality.
• Temporary sediment trap: A temporary sediment trap is a control device used to intercept sediment-laden runoff and to trap sediment and prevent or reduce off-site sedimentation. A temporary sediment trap can be formed by excavation or by embankments constructed at designated locations that are accessible for cleanout.
• Diversions: A diversion is a dike, a ridge, an excavated channel or a ditch used to prevent sediment-laden waters from leaving a site and to prevent off-site or upstream waters from entering a site. Typical diversions are a combination of two or more types and may be temporary or permanent structures.
• Check dams: Check dams are small, temporary dams constructed across a swale or channel. They can be constructed using gravel, straw bales, sand bags or fiber rolls and are used to reduce the velocity of concentrated flow and, therefore, to reduce the erosion in a channel or ditch.
• Rock dam sediment basins: A rock embankment may be used as an alternative to a standard sediment basin for a drainage area of 20 acres or less. It may be preferable to standard sediment basins where an earthen embankment would be difficult to construct. Dam height is normally limited to 8 feet and the design life to three
• Inlet protection: A temporary, woven, high-strength textile barrier can be placed around a drop inlet to prevent sediment from entering storm drains during construction. This practice applies where early use of the drains is necessary.

Adapted from: 'Controlling Runoff and Erosion at Urban Construction Sites,' Bob Broz, Don Pfost and Allen Thompson, Biological Engineering Department and MU Extension, a tutorial with emphasis on techniques, http://muexten-sion.missouri.edu/explore/agguides/agengin/g01509.htm 

Residential Water Usage

Residential Water Usage
The average family's indoor water usage is about 50 gallons of water per person per day. Flushing the toilet accounts for about 42 percent of the total, bathing is 32 percent, and laundry is 14 percent. The amount of water that is used for drinking or cooking is probably less than 4 percent of the total.

The Energy Policy Act of 1992 has maximum water-use standards for plumbing fixtures. Toilets manufactured after January 1, 1994, have a 1.46 gallon per flush flow (as opposed to 3.5 or 5 gallons per flush for older units), and shower heads will have a maximum flow rate of 2.5 gallons per minute. Replacing a shower head or an older-model toilet is a good investment.

Efficiency Hints

• Fix all leaks promptly;
• Don't let the water run while shaving or brushing your teeth;
• Use low-flow shower heads and faucet aerators;
• Take short showers and don't overfill the bathtub;
• Use your dishwasher wisely instead of washing dishes by hand;
• If you wash dishes by hand, don't let the water run for rinsing;
• Use full loads in your dishwasher and in the washing machine.

Lawn Irrigation
An irrigation system can be the most efficient method of watering a landscape if it is correctly designed, maintained, and calibrated according to plant needs and weather conditions. An owner should be aware of the system's operations and be alert to signs of trouble with equipment or scheduling. It's also important to adapt the system to maturing landscape and to consider improvements that can increase efficiency.

Good water management can improve lawn quality and lower water bills. Your choice of grass species will determine water needs. For example, a lawn of Kentucky bluegrass will demand higher input of water, chemicals and labor than any other type of grass. It needs more water than other grasses (1.2 inches weekly), but many owners give bluegrass excess water. Turf-type tall fescues have greater heat and drought tolerances than bluegrass and are better adapted to partial shade and they require only .8 inch of water per week. Zoysia or Bermuda grass lawns require only .5 inch per week.

Mowing height and frequency can affect water consumption as well. Slightly taller grass will develop deeper, more drought-hardy roots.

Efficient Irrigation

• Water your lawn only when needed;
• Water grasses heavily and deeply when they begin to wilt. Frequent, sprinkling produce poor root development
• Water during the coolest part of the day, generally early in the morning;
• Don't water during windy conditions;
• Position sprinklers so they water the lawn, not the pavement;
• Use mulch on your garden and flower beds to help keep soil moist. Use a broom, not a hose, to clean driveways and sidewalks;
• Don't run the hose while washing your car;
• Avoid letting children play in the hose or sprinkler;
• Check and repair leaks in hoses, hose couplings and outside faucets;
• Plant drought-resistant plants and trees;
• Use a water timer on hose sprinklers.

Adapted from: Missouri Department of Natural Resources, Outreach and Assistance Center, "Residential Energy Efficiency Water Usage," http://www.dnr.mo.gov/energy/residential/waterusage.htm

Wastewater Treatment Facilities (WWTF)