-Pollution Prevention In Your Hands - Construction BMPs - Long-term Stormwater BMPs -
-
Low Impact Development - Stream Crossing BMPs - Forestry BMPs -
Activities we conduct in our day-to-day lives, whether a significant effort like building a new home or something more mundane like washing a car, have an impact on the environment. “Best management practices” (BMPs) are simply a different way to go about those activities in ways that are more environmentally friendly. Because BMPs are designed specific to a project, its location, and the environmental effects trying to be minimized (e.g. stormwater runoff vs. dust control), BMPs are as diverse as the ways in which we change the landscape. Some BMPs are as simple as washing your car on the grass instead of in your driveway, while others are based on the most current water treatment technology.
The Cumberland HCPs are designed to avoid, minimize, and mitigate for impacts of human activities on threatened and endangered species. The minimization component of the HCPs is addressed through the use of BMPs. Below is a sampling of BMPs pertinent to the HCP covered activities. (Note – Agriculture is not a covered activity under the Cumberland HCPs. To learn more about agricultural BMPs in Tennessee, start here or contact your local UT Extension Agent).
Pollution Prevention In Your Hands
There are many ways you can help protect water quality and threatened and endangered species in the Cumberlands.
What you can do… |
Around the House
|
- Make sure all faucets are completely turned off when not in use.
- Fix leaky faucets and toilets.
- Turn off faucets while shaving or brushing your teeth.
- Run the dishwasher and clothes washer only when they’re full.
- Install aerators in the faucets in your kitchen and bathroom
- Install low-flow showerheads and toilets.
- Dispose of unwanted pharmaceuticals in the trash, not the toilet or sink.
- Take unused cleaning products, leftover paint, and other chemicals to a hazardous waste collection event (contact TDEC or your City/County)
|
Septic System Care
|
- Inspect your system every 2 to 3 years and pump as recommended.
- Use water efficiently.
- Use toilets to flush waste only (not kitty litter, diapers or other trash).
- Don’t dispose of household hazardous wastes in sinks or toilets.
- Care for your drain field. Avoid driving or parking vehicles on your drain field. Plant only grass over and near your drain field to avoid damage from roots.
|
Lawn and Garden Care
|
- Become involved in the Tennessee Yards and Neighborhoods Program (contact Cumberland County Yards and Neighborhoods Program for information).
- Fill out the ”Tennessee Yardstick Workbook” and use its advice to make your yard more environmentally friendly.
- Plant grass or other vegetation in bare areas of your yard.
- Direct downspouts to areas with vegetation, not driveways or sidewalks.
- Use pesticides and fertilizers sparingly.
- Irrigate only when plants need water, and then early in the morning or in the evening.
- Compost yard waste instead of sweeping it into the street.
- Follow the application instructions closely for any fertilizers or pesticides.
- Sweep up any fertilizer that is spread onto driveways or sidewalks.
- Maintain natural vegetation and use native plants to provide wildlife habitat.
- When replacing a driveway, sidewalk, patio, or deck, consider materials that allow water to soak into the soil (e.g. brick, gravel, or paving stones) instead of asphalt or concrete.
If you use a lawn service, ask them questions about these and other best management practices that they follow.
|
Car Care
|
- Use a commercial car wash that treats or recycles its wastewater.
- Wash your car on your yard (instead of the driveway) so the water infiltrates into the ground.
- Inspect your car and repair leaks promptly.
- Dispose of used auto fluids and batteries at designated drop-off or recycling locations (contact a local auto parts store, TDEC, or your City/County for locations).
|
Managing Pet Waste
|
- When walking your pet or in your yard, pick up their waste and dispose of it properly. Flushing pet waste or bagging it in the trash is best. (Composting is an option, but the location needs to be chosen carefully because buried pet waste can be a health risk if it is close to a garden or play area).
|
Structural Stormwater BMPs
Stormwater is often seen as a nuisance and potential threat to be managed. Structural stormwater BMPs minimize these threats by decreasing pollutant levels and increasing infiltration. These principles help protect downstream water quality, minimize flooding, and decrease streambank erosion. However, stormwater can also be seen as a resource. BMPs that increase infiltration help recharge groundwater which maintains streamflow during periods of drought and provides the instream flow needed to buffer wastewater plant discharges. Storwmater can also be stored and reused for irrigation. The variety of stormwater BMPs reflects the diversity in stormwater impacts and potential benefits. The following principles are key to effective stormwater treatment:
- Preserving and using existing natural features and treatment processes;
- Managing stormwater as close to the source as possible;
- Sustaining the hydrologic balance of surface and ground water;
- Disconnecting, decentralizing and distributing sources and discharges;
- Slowing runoff down, not speeding it up;
- Extending the time it takes for water to travel from the source to the receiving water;
- Preventing potential water quality and quantity problems;
- Minimizing problems that cannot be avoided;
- Integrating stormwater management into the initial site design process; and
- Inspecting and maintaining all BMPs.
Key resources for more information:
Below is a description of common storwmater BMPs (primarily from EPA’s Overview of Stormwater BMPs).
Storwmater BMPs Focused on Managing Water Quality |
BMP |
Description |
Applicability |
Bioretention |
Bioretention areas are landscaping features adapted to provide on-site treatment of stormwater runoff. Bioretention areas are shallow, landscaped depressions with an engineered “layer cake” of the soil/planting mixture, a gravel bed, filter fabric, and an under drain system which connects to a storm drain.
Bioretention uses the chemical, biological and physical properties of plants, microbes and soils to treat stormwater. Bioretention areas can also be designed to manage stormwater volume by mimicking natural hydrologic conditions. |
Bioretention is well suited to integration in urban landscapes such as parking lots and can provide significant aesthetic benefits as well as stormwater management.
Because they contain an underdrain system, bioretention areas can treat more stormwater than a typical rain garden. |
Catch Basin Inlets |
Catch basin inlets, also known as storm drain inlets or drop inlets, are a basket and a sump placed inline with the gutter to capture sediment, debris, and pollutants. The ability of catch basins to remove sediments and other pollutants depends on its design and maintenance procedures to regularly remove accumulated sediment. |
Typically used as pretreatment in combination with other BMPs or in areas where trash removal is the key goal. Applicable to settings where a storm sewer system exists. |
Constructed Wetlands |
Constructed wetlands are essentially wet ponds that incorporate wetland plants into the design. As stormwater runoff flows through the wetland, pollutant removal is achieved through settling and biological uptake. Wetlands are among the most effective stormwater practices in terms of pollutant removal and they also offer aesthetic and wildlife benefits. As opposed to natural wetlands (which should not be used for storwmater treatment), stormwater wetlands are designed specifically for the purpose of treating runoff and typically have less biodiversity than natural wetlands. |
Because of flexibility in their design, constructed wetlands are applicable in many urban and rural settings and can provide long-term stormwater treatment benefits. |
Dry Ponds |
Dry detention ponds (a.k.a. detention ponds, extended detention basins) are basins whose outlets have been designed to detain stormwater runoff for a set time to allow sediment and pollutants to settle. Unlike wet ponds, dry ponds do not have a large permanent pool of water. They can also be used to provide flood control by including additional flood detention storage. |
Dry ponds generally provide less pollutant removal benefits than wet ponds, but can have significant volume control benefits. Dry ponds are widely applicable, with the exception of highly urbanized settings (due to land availability). |
Hydrodynamic Separators |
A variety of products called swirl or hydrodynamic separators contain an internal component that creates a swirling motion as stormwater flows through a cylindrical chamber. This traps oil and trash and allows sediment to settle out. Regular maintenance is key to the performance of hydrodynamic separators. |
|
Infiltration Trenches |
An infiltration trench is a rock-filled trench with no outlet. Stormwater runoff passes through a combination of pretreatment measures, such as a swale and detention basin, and into the trench. There, runoff is stored in the void space between the stones and infiltrates through the bottom and into the soil matrix. The primary pollutant removal mechanism of this practice is filtering through the soil. |
Infiltration trenches can be used in areas where minimal land is available for stormwater infrastructure. They are typically paired with another BMP in a treatment train. |
Pervious Concrete |
Pervious concrete is concrete with reduced sand or fines and allows water to drain through it. Pervious concrete is installed over a gravel storage bed that reduces stormwater runoff volume, rate, and pollutants. |
Pervious pavement has significant benefits in managing stormwater in developments with little open space. |
Rain Gardens |
Rain gardens are used to manage and treat small volumes of stormwater runoff using a conditioned planting soil bed and planting materials to filter runoff stored within a shallow depression. They are most commonly used in residential settings. Rain gardens are typically smaller than bioretention and are generally designed as a more passive filter system without an underdrain. |
Rain gardens can provide significant aesthetic benefits and are feasible for individual homeowners to install (see the TN Yards and Neighborhoods Program for more details). |
Riparian Buffers |
A riparian or forested buffer is an area of natural (or restored) vegetation along a shoreline, wetland, or stream across which water flows before entering the waterbody. Riparian buffers situated in flat soils effectively remove sediment, nutrients, and bacteria from stormwater and can reduce water temperatures. Buffers can also provide wildlife habitat. The most significant benefit of riparian buffers is minimizing streambank erosion, especially when paired with a filter strip or spreader swale that maintains sheet flow through the buffer. |
Riparian buffers are widely used in both rural and urban settings. Buffers represent a key conservation measure in the Northern Cumberlands Forest Resources HCP. |
Sand Filters |
Sand filters contain a filter bed filled with sand or another filtering media. As stormwater flows into the first chamber, large particles settle out, and then finer particles and other pollutants are removed as stormwater flows through the filtering medium. In addition to reducing pollutants, sand filters can help reduce runoff temperature. |
As flow-through systems, sand filters generally do not provide volume reduction benefits and thus are limited to small drainage areas. |
Swales |
The term swale (a.k.a. grassed channel, dry swale, wet swale, biofilter, or bioswale) refers to a vegetated open channel designed specifically to slow and infiltrate stormwater runoff. As stormwater flows through a swale, sediment is removed by slowing down the water and infiltration provides pollutant removal and groundwater discharge benefits. Riparian buffers differ from filter strips in that water flows lengthwise down a swale, instead of crosswise through a filter strip or buffer. |
Swales are well suited for treating highway or residential road runoff because they are linear practices. Swales are also useful as part of a treatment train conveying water between other BMPs. |
Vegetated Filter Strips |
Vegetated filter strips (a.k.a. grassed filter strips, grassed filters) are vegetated surfaces that are designed to treat sheet flow from adjacent surfaces. Filter strips slow runoff velocity and filtering out sediment and other pollutants, and provide some infiltration into underlying soils. With proper design and maintenance, filter strips can provide relatively high pollutant removal. Maintaining sheet flow through the filter strip (as opposed to channelized flow) is critical to its effectiveness. Filter strips differ from riparian buffers in that they are not always located directly adjacent to a waterbody. |
Filter strips are best suited to treating runoff from roads and highways, roof downspouts, very small parking lots, and pervious surfaces. They are also ideal components of the "outer zone" of a stream buffer (see Riparian/Forested Buffer fact sheet |
Wet Ponds |
Wet ponds (a.k.a. stormwater ponds, wet retention ponds, wet extended detention ponds) are constructed basins that have a permanent pool of water for extended periods of time during the year. Ponds treat incoming stormwater runoff by allowing particles to settle and algae to take up nutrients. The primary removal mechanism is settling as stormwater runoff resides in this pool, and pollutant uptake, particularly of nutrients, also occurs through biological activity in the pond.
What is the difference between retention and detention? |
As with dry ponds, wet ponds are widely applicable, except in highly urbanized settings. |
Subdivision Design
One of the most effective best management practices is thoughtful subdivision design that minimizes the impact of development on aquatic and terrestrial habitats. This approach falls under the umbrella of “Low Impact Development” or “LID.” In an LID approach, BMPs are integrated into the subdivision design and put into place prior to construction, in contrast to traditional stormwater BMPs which are typically fit into the landscape after the site plan has been developed. One of the primary goals of the LID approach is to reduce the impervious footprint of a site, thus decreasing the overall amount of stormwater generated by the development. Less stormwater generated means less to treat and fewer impacts to streams and rivers. Stormwater that remains is detained in small-scale stormwater management features and slowly released downstream, mimicking natural hydrology and allowing time for natural physical, chemical, and biological process to improve stormwater quality. The LID approach is particularly effective when practices are linked from the lot scale up to the subdivision scale. In addition to stormwater benefits, decreasing the footprint of development can also result in preservation of natural land cover, bringing the habitat protection and economic benefits of mature forest habitat to the community.
Cluster development, a key LID approach, is an excellent example of how subdivision design can work to protect aquatic and terrestrial habitat. Traditional subdivision design results in larger lots with less intact natural areas/habitat being preserved. In a cluster design, smaller house lots result in more acreage of natural lands/habitat being protected and incorporated into the subdivision as common open space. Although specific to each development, the financial benefits of proximity to natural areas can offset the financial impacts of smaller lot sizes.
When combined with smaller minimum road widths, landscaping islands in cul-de-sacs, minimal cul-de-sac sizes, smaller minimum parking requirements, and similar design decisions in residential and commercial developments, a clustering approach can also result in less road and utility infrastructure required to serve the development. Adding in stormwater BMPs such as pervious pavement, swales, bioretention, and rain gardens further minimizes the effect of development on aquatic and terrestrial species.
LID has tremendous potential within the HCP to bring together development and the avoidance and minimization of covered species impacts.
More information about the LID approach to subdivision design:
Construction Site BMPs
Bare dirt + rain = erosion. It’s a simple equation, but it does not always have to be true. Construction activities near waterways have significant potential to cause water pollution and stream degradation. However, many BMPs are available (and required by TDEC on most construction sites) to manage the effects of construction site erosion.
Contact TDEC for more information about construction site runoff permitting:
Example Construction Site BMPs |
Project Sequencing |
The sequencing of tasks during construction can minimize 1) the amount of bare dirt at any given time; 2) the total disturbed area; and 3) soil compaction. Minimizing soil compaction helps maintain the ability of water to soak into the ground – the best way to prevent erosion. |
Storm Drain Inlets (Crossville): |
Inlets can be protected with gravel filled sand bags or similar material that slows down water and allows sediment to settle out before stormwater enters the storm drain. |
Truck Entrance |
A gravel entryway for construction vehicles minimizes sediment that is tracked off-site. |
Site Stabilization |
After earth is disturbed or exposed, bare soil should be stabilized with vegetation or mulch as soon as possible to reduce erosion. |
Structural Sediment Controls |
Dikes, silt fences, sediment basins, or sediment traps are examples of this type of control. These methods divert runoff, filter out sediments, and reduce runoff velocity so sediments can naturally settle out. |
Material and Chemical Storage |
Soil stockpiling must be done with care. Stockpiles should not be
located near water bodies or storm drains. Silt fencing can be used around stock piles. Plastic covers can be used to minimize erosion.
Solvents, paints, cements, bonding agents, fuels, etc. have a high potential to
cause water pollution. Pollution from these chemicals can be prevented by installing a containment structure around fuel tanks and fueling areas and storing solvents, paints, etc. in an enclosed structure. |
Concrete Washing |
A dedicated area where concrete equipment is washed helps minimize polluted runoff. |
Equipment Maintenance and Repair |
Confine maintenance, repair, and fueling activities to a specifically designated
area. Inspect equipment regularly and repair leaks promptly. |
Dewatering |
Cloudy water from a sump hole can be impounded to allow particles to settle out or infiltrate into the soil. |
Inspection and Maintenance |
Structural controls need to be inspected and maintained throughout construction to ensure they are serving their purpose. |
Stream Crossing BMPs
Bridges and culverts have potential to directly impact aquatic species. Impacts include physical barriers presented by a vertical drop at the inlet or outlet of a culvert, high and low flow extremes, turbulence, debris accumulation, sedimentation from streambank erosion, and loss of stream substrate. These direct effects can also cut off fish from upstream or downstream habitat, isolating populations and limiting reproductive success. Modifications to culvert shape, depth, slope, materials, bridge pylon design, and similar BMPs can minimize the negative effects of stream crossings on aquatic species. The Cumberlands HCP may include stream crossings as a covered activity. See the CHCP page for more details.
More information about fish-friendly culvert design:
National Fish Passage Program (USFWS)
Planning, Design, and Construction of Fish-Friendly Stream Crossings (USFWS)
Biologically Sound Stream Crossings
Landowners Guide to Building Forest Access Roads (US Forest Service)
Forestry BMPs
Tennessee has adopted BMPs for forestry operations. BMPs apply to road construction, log landings, skid trails, and harvest locations to minimize the environmental impact of forest management and logging activities. They are designed to be low-cost, practical and easily applicable to all forestry operations. During development of the FRHCP, TWRA evaluated the state forestry BMPs and identified those which they could implement more intensively to protect threatened and endangered species. Requirements of the Sustainable Forestry Initiative certification program were also evaluated. See the FRHCP page for more details.
|
