Questions & Answers

 

 

What is erosion and sediment controls?

Erosion Control is the practice of preventing or controlling wind or water erosion in agriculture, land development, coastal areas, riverbanks and construction. It is important to control erosion and sediment when doing construction, especially near stream banks to prevent sediment from entering the stream and harming aquatic life. Erosion control involves protecting the soil surface against erosion with the goal of keeping sediment in place. Some strategies for erosion control are surface mulch, seeding to establish vegetative cover before construction and erosion control blankets, mats and wattles.

 

A Sediment Control is a practice or device designed to keep eroded soil on a construction site, so that it does not wash off and cause water pollution to a nearby stream, river, lake, or sea. Some methods include silt fences, sandbag barriers, riparian vegetation, storm inlet filters, etc.

 

 

 

Why is erosion a potential environmental issue?

Erosion Control is nothing to take lightly. In addition to posing a threat to the environment via sediment runoff that pollutes storm drains, nearby streams and other bodies of water, storm water related erosion poses immediate health and safety concerns to your employees, site occupants and neighbors. It is a natural process affected by human activities. Erosion causes soil or layers of soil to be moved or worn away. Erosion is a potential environmental issue because it usually washes away nutrient rich topsoil from lands. Because of this, erosion is considered one of the most influential natural forces in nature.

 

Water Erosion is typically erosion caused by water that begins at the surface and as the first layer of dirt and vegetation or ground cover is washed away, the ensuing water will continue to etch it's way through longer and deeper sections of earth. In worst-case scenarios, water runoff causes deep, wide areas of stream and channel erosion, resulting in thousands of pounds of displaced earth that winds up being deposited elsewhere.

 

 

 

Why is erosion and sediment control important?

Erosion and sediment control is very important because erosion affects wildlife, public and private property, and contributes to pollution. Job site erosion control is especially important because excess dirt, construction materials, chemicals, and other pollutants will be carried into runoff, if proper steps are not taken.

 

 

 

What is stormwater runoff?

Stormwater runoff is natural precipitation from rain or melting snow that does not soak into the ground where it falls. When rain hits hard, impervious surfaces such as driveways, sidewalks, streets, rooftops and parking lots, it channels the runoff toward stormwater drainage systems transporting soil, sewage, sludge, chemical wastes, pesticides, fertilizers, oil, grease, leaves, litter, radioactive materials, rock, agricultural waste and other harmful pollutants. In most communities, these drainage systems empty into natural waterways. As a matter of fact, you don't even need a heavy rainstorm to send pollutants rushing toward streams, wetlands, lakes, rivers and oceans. Even areas that are not close to a waterfront are impacted by polluted storm water. Contrary to popular belief, most storm sewers do not carry storm water to wastewater treatment plants. Storm and sanitary sewers may even be combined in some older communities.

 

 

 

Why is stormwater runoff a problem?

Urban and suburban stormwater runoff is untreated. It clouds water, degrades habitat for fish and water plants, pollutes swimming areas, erodes streams, floods homes, degrades our lakes, wetlands and rivers and causes many other problems. Nutrients such as phosphorus and nitrogen promote the growth of algae, which crowds out other aquatic life. Toxic chemicals, such as antifreeze, oil from leaking cars, carelessly applied pesticides, and zinc from galvanized metal gutters and downspouts can threaten 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.

 

As many people have discovered, storm water can be a problem closer to home. It can flow into basements and cause damage that is difficult and costly to clean up. Storm water can also flow down a poorly sealed well shaft and contaminate drinking water. In areas with very porous soils or geology, pollutants in runoff may reach groundwater.

 

 

Negative effects of uncontrolled stormwater runoff:

•  Large volumes can overwhelm storm drains causing localized flooding & stream bank erosion
•  Contaminated streams, rivers and coastal water causes habitat destruction and infrastructure damage
•  Increased turbidity (muddiness is created by stirred up sediment) from erosion
•  Runoff gathers sediment and pollutants, which can wind up in natural waterways
•  Water that doesn't soak into soil cannot recharge local groundwater sources.
 
 

 

 

Common sources of storm water pollutants:

 

Pollutant Common Sources
   
Silt, sand, clay particles, other debris Construction sites; bare spots in lawns and gardens; wastewater from washing cars and trucks on driveways or parking lots; unprotected stream banks
   
Nutrients Over-used or spilled fertilizers; pet manure; grass clippings and leaves left on streets and sidewalks; leaves burned in ditches
   
Disease organisms Pet manure and garbage
   
Hydrocarbons Car and truck exhaust; leaks and spills of oil and gas; burning leaves and garbage
   
Pesticides Pesticides over-applied or applied before a rainstorm; spills and leaks
   
Metals Cars and trucks (brakes and tire wear, exhaust); galvanized metal gutters and downspouts

 

 

Land Development and Construction Site Operations:

When it rains, stormwater washes over the loose soil on a construction site, along with various materials and products being stored outside. As stormwater flows over the site, it can pick up pollutants such as building materials, concrete washout waste, paint, fuel, wastewater, oil,  solvents, sediment, debris, and chemicals from the loose soil and transport them to nearby storm sewer systems or directly into rivers, lakes, or coastal waters.

 

Land Development and Construction site operations are heavily regulated and enforced upon by federal, state, and local storm water agencies. The purpose is to make sure they have the proper stormwater controls in place so that construction can proceed in a way that protects your community’s clean water and the surrounding environment.

 

The NPDES stormwater program requires permits and control measures for discharges from construction activities that disturb one or more acres, and discharges from smaller sites that are part of a larger common plan of development or sale. Depending on the location of the construction site, either the state or EPA will administer the permit.

 

 

If your project is greater than 1 acre or you’re building in a larger common plan of development, you are required by the State of Texas, and many other states, to comply with the storm water regulations stated in the construction general permit. These regulations affect new construction, additions to existing projects, demolitions, off-site/utility construction, and linear construction. These regulations can be extremely costly and confusing! We want to make sure that you maintain compliance by having the proper erosion and sediment control measures installed in order to avoid fines or work stop orders, and we want to keep your cost of compliance as low as possible.

 

 

The goal of managing stormwater runoff includes:

•  Decreasing the volume
•  Minimizing the pollutants
 

The EPA mantra for stormwater runoff management is:

1) slow it down
2) spread it out
3) soak it in

 

Understanding the basic principles of erosion and sediment control?

♦  Reduce erosive forces and increase resistive forces: Reducing the amount of power exerted by water and wind, combined with implementing techniques that resist these forces are the overarching goals of any erosion control program.

♦  Implement erosion and sediment control. It is almost always more cost-effective to prevent the erosion of sediment than it is to pay for the equipment/man power required to remove sediment that has been deposited elsewhere.

♦  Modify topography: Short, shallow slopes will erode slower and allow erosion-preventative vegetation to take root more firmly than longer, steeper slopes.

♦  Limit soil exposure. The less contact soil has to water and wind, the less it will erode. Leave vegetation and other shelter in place wherever necessary and try to divert excess water away from exposed soil when possible. Also, try to schedule activities that disturb established soil during the dryer seasons, avoiding ground disturbance when water and wind are more likely.

♦  Protect Trees and add plants:  Like other plant roots, tree roots help absorb and filter runoff. Tree canopies also slow rainfall and spread it over a larger area. Incorporate vegetation and plantings, especially in areas where runoff collects. As runoff soaks into the soil, plant roots help to absorb and filter out pollutant.

♦  Reduce runoff velocity. Altering slope, and increasing surface roughness via specialized grading, rock dams and so on will help to reduce runoff velocity. Keep in mind that rock dams are not recommended for steeper slopes.

♦  Inspect and repair regularly. Once in place, erosion control techniques should be inspected on a regular basis. They should be evaluated within 24-hours after a storm, at least every seven days while a site is active and approximately every 14-days on inactive job sites.

 

The goal is always to use the smallest time and cost investment initially, implementing thoughtful and efficient erosion control methods, to avoid costly repairs, fines and damage down the road.

 

Meet with the local building department

In an effort to reduce erosion on active construction sites, many city councils and building departments have put specific ordinances into place. These ordinances are designed to accommodate the region's typical climate patterns and may also have stipulations in place for more severe weather patterns as well. In many cases, erosion and sediment control measures are required to be put in place between certain calendar dates, regardless of whether or not it rains or snows.

 

Observe drainage patterns on the property

If you have the luxury of observing a job site in the midst of, or directly after, a storm - lucky you. You'll be able to watch water runoff in action. If not, walk the property and look for evidence of water runoff and sediment deposits via rivulets, seasonal stream beds or recent sand and gravel deposits. This will give you an idea of how water moves naturally, and you can augment this movement accordingly.

 

What is a BMP?

In the context of Civil Engineering, it's referring to Best Management Practice. ... BMP's are basically split up into two separate categories: Construction level, and Permanent. Construction level BMP's are erosion and/or sediment control measures put into place that help prevent pollutants from the construction site from reaching storm sewers.

 

Some Effective Ways to Control Erosion & Sediment at Construction Sites:

Several things can be done to prevent erosion and sedimentation at your construction site, from installing fences and storm inlet protection to planting vegetation or installing a BMP facility. Below are some erosion and sediment control products that we offer:

 

Every situation calls for specific solutions based on the site and the severity of the problem. Controlling erosion and sedimentation is important not just for preserving the construction site and protecting the new structure but also for minimizing the environmental impact that the project has on the surrounding area. Manufacturers are continually developing innovative products to minimize cost as well as environmental impact. 

 

 

 Geotextile Fabrics

Geotextiles are commonly used to control erosion and improve soils over which roads, embankments, pipelines, and earth-retaining structures are built. Depending on the application, geotextiles may have an open mesh weave, a warp-knitted structure, or a closed fabric or nonwoven surface. The specific type of geotextile used is based on several criteria, including separation, filtration, drainage, reinforcement, sealing, and protection.

 

 

 

Erosion Control Blankets

Erosion Control Blankets are biodegradable materials that can be used to protect disturbed slope and channel areas from wind and water erosion. The blanket materials are natural materials such as straw, wood excelsior, coconut, or are geotextile synthetic woven materials such as polypropylene.

 

 

 

Coconut Coir Logs

Coconut Coir Logs are biodegradable fiber rolls for erosion control on hills, banks, shorelines, and other erosion prone areas. Easy to place, use, and install, our coir fiber logs create a natural control area that helps establish growth and control erosion.

 

 

 

Geogrid

A Geogrid is geosynthetic material used to reinforce soils and similar materials. Geogrids are commonly used to reinforce retaining walls, as well as subbases or subsoils below roads or structures. Soils pull apart under tension. Compared to soil, geogrids are strong in tension.

 

 

 

Inlet Protection Products

Inlet protection products are a solution to filter runoff water around a storm drain drop or curb inlet. Our products help prevent sediment, debris and other particles from entering any storm drainage system

 

 

 

Silt Fences

Silt fences control sediment runoff from construction sites during active construction. Silt Fence slows the water long enough to cause sediment to drop out, allowing water to pass through the fabric. Slit fences are designed to capture sediment at the base of slopes but are not intended for use on slopes or around storm drains. Incorrect installation and use of slit fences can increase erosion damage so use best practices when implementing this method.

 

 

 

Straw Wattles

Straw erosion wattles are a great option for filtration around storm drains, construction perimeters and other areas dealing with erosion or polluted storm water runoff. Wattles are round in structure and are most are commonly used on slopes, streams and other low flow areas. They are designed to naturally biodegrade over short periods of time.

 

 

Taking the extra time to implement erosion control methods on the job site protects the environment and makes for safer and more pleasant job site conditions for you and your employees.