Recently in Hardscape Category

Stormwater runoff in urban and suburban areas is one of the leading sources of water pollution in the United States. Runoff can cause increased flooding and erosion and more pollution to surface waters.

EPA is using sustainable techniques for reducing the effects of stormwater runoff at its facilities, such as installing a 3,000 square foot green roof as well as using rain gardens and cisterns to capture and reuse stormwater.

The U.S. Environmental Protection Agency (EPA) has issued guidance to help federal agencies minimize the impact of federal development projects on nearby water bodies. The guidance is being issued in response to a change in law and an Executive Order signed by President Obama, which calls upon all federal agencies to lead by example to address a wide range of environmental issues, including stormwater runoff.

Peter S. Silva, assistant administrator for EPA's Office of Water said, "By taking these steps to create more sustainable facilities, federal agencies can lead by example in reducing impacts in the local watershed."

EPA worked closely with other federal agencies to develop this document, which provides background information, key definitions, case studies and guidance on meeting the new requirements of the Energy Independence and Security Act of 2007.

Under the new requirements, federal agencies must minimize stormwater runoff from federal development projects to protect water resources.

Federal agencies can comply using a variety of stormwater management practices often referred to as "green infrastructure" or "low impact development" practices, including reducing impervious surfaces, using vegetative practices, using porous pavements and installing green roofs.

More information on the guidance: http://www.epa.gov/owow/nps/lid/section438/

Did you know... 65% of new impervious cover can be classified as car habitat!

What is "car habitat"?  

"...the geometry of roads, parking lots, sidewalks, cul-de-sacs and other new development infrastructure."  That's car habitat.

Local development codes enforce how much impervious surface is allowed.  They take into consideration how water drains and is absorbed by local soil conditions, as well as the level of development already affecting the watershed.

Better site design can reduce flooding by improving absorption of heavy water deluges into nature's groundwater infrastructure.  Snowpack might be nature's LARGEST water reservoir, but groundwater is also a very valuable service provided by nature in lowlands. 

Better Site Design (BSD), can include greater use of

• swales
• relaxed lot geometry
• natural area conservation
• open-space subdivisions
• pervious paving
• and other site design techniques

Several dozen communities across the country have changed their local codes and ordinances to promote BSD through a roundtable process to gain consensus among development stakeholders.

Better Site Design Can Reduce Development Costs

The strength of the BSD approach is that numerous modeling studies have demonstrated it can reduce impervious cover, pollutants and development costs by as much as 10 to 40% at individual development sites.

The weakness of BSD is that it lacks a watershed context and therefore reductions in site IC may be not be enough to meet subwatershed objectives.

SOURCE:
Chesapeake Stormwater Network, CSN Technical Bulletin No. 3, "Implications of the Impervious Cover Model".

Wading through the sources of lake contamination

Contamination of urban lakes and streams by polycyclic aromatic hydrocarbons (PAHs) is widespread and has been increasing over the last 40 years in the United States.

PAHs are Toxic to Fish Humans and Other Organisms

These PAHs can be toxic to bottom-dwelling organisms, can cause tumors in fish, and several are believed to cause cancer in humans. 

In this study, researchers examined five sources of PAHs in 40 urban lakes from across the United States, including coal-tar-based pavement sealcoat, coal combustion, oil combustion, vehicle emissions and wood combustion.

Sealcoat Contributes to PAH Contamination

Of the five sources studied, sealcoat was the strongest contributor to PAH contamination in lake sediment. This research can help those trying to reduce pollution levels in the urban environment by providing them with a better understanding of PAH sources. 

This study, "Sources of PAHs to urban lakes in the United States," was conducted by USGS at the Society of Environmental Toxicology and Chemist  

To remove debris from sidewalks and driveways, sweep or blow,
never use a hose to wash these areas.

Make sure sprinklers don't water the driveways or sidewalks. This contributes to stormwater runoff, taking the oils and chemicals to the creeks, lakes and drinking water supply.

Permeable Hardscape

Another solution is to provide paving with holes for plants to grow in...or permeable concrete that is so porous that water will drain right through it.

Research is showing that plants and the microbes in the soil are our best friends -- they work constantly to remove pollutants from groundwater -- so take advantage of this free filtration system by respectfully directing rainwater, stormwater and your home wash water INTO the ground.  The earthworms will thank you !