New Contruction Turbidity Standards

Land and Water Magazine: Reducing Turbidity, ELG’s, and Compost-Based BMPs

Summary

The final rule for the US EPA Effluent Limitation Guideline for the Construction and Development Industry (40 CFR Part 450 of the Federal Register) went into effect in February 2010. The new rule creates storm water quality performance standards for soil disturbance on construction sites 10 acres or greater. The land owner will be required to monitor and report the daily average nephelometric turbidity (NTU) from waters discharged from the construction site. The turbidity standard (numerical limit) to trigger a violation was originally 280 NTUs.

Under the current rule, the US EPA will begin enforcement on construction sites with a total active soil disturbance of 20 acres of 20 acres or greater as of August 2011. Sites that disturb 10 acres or greater will undergo active enforcement starting February 2014. For large developments this includes the sum total area of disturbance at any given time, including small sections under the acre limit.

Effluent Limitation Guideline (ELG) states the permitted party must report the daily average turbidity from all site storm water discharge areas. A violation will only occur if the daily average exceeds the NTU threshold, whereas, one reading in breach of the NTU limit does not constitute a violation. Also, if the 2yr 24hr storm event is surpassed for the local area where the construction site is located, the turbidity standard will not be enforced.

Storm water sampling frequency, number of daily samples required, sampling methodology, sampling equipment, method of measurement, and reporting method is up to the local permitting authority. Although, the US EPA will likely release a guidance document which will likely steer the permitting authorities.

The Final Rule does not dictate what type of best management practices can be used as the US EPA does not want to limit strategies that may help permitted parties comply with the new rule. They estimate that full enforcement and compliance with the new rule will encompass 73% of construction site soil disturbance nationally and should reduce annual sediment discharges from construction sites by 77%

For those with sites of 20 acres or greater, this rule will be effecting you very soon. The new standards have been described as strict and depending on the site type may be difficult to comply with. Remember that the owner is in-charge of reporting the daily average NTU, and should also be considering ways to reduce the turbidity level to keep it under limitations. The link below gives an article which includes suggestions for reducing turbidity levels: http://viewer.zmags.com/publication/f15cb27c#/f15cb27c/24

EPA Launches Green Infrastructure Strategy

WASHINGTON – The U.S. Environmental Protection Agency (EPA) is launching a new strategy to promote the use of green infrastructure by cities and towns to reduce stormwater runoff that pollutes our nation’s streams, creeks, rivers, lakes and coastal waters. Green infrastructure decreases pollution to local waterways by treating rain where it falls and keeping polluted stormwater from entering sewer systems. In addition to protecting Americans’ health by decreasing water pollution, green infrastructure provides many community benefits including increased economic activity and neighborhood revitalization, job creation, energy savings and increased recreational and green space.

“Through this agenda, we’ll help cities and towns across the nation clean up their waters and strengthen their communities by supporting and expanding green infrastructure,” said Deputy Administrator Bob Perciasepe, who announced the agenda at a Green Street, Green Jobs conference focused on fostering green infrastructure in the Washington, DC metropolitan area. “Green infrastructure changes improve the health of our waters while creating local jobs, saving communities money and making them healthier and more prosperous places to raise a family and start a business.”

Stormwater is one of the most widespread challenges to water quality in the nation. Large volumes of polluted stormwater degrade our nation’s rivers, lakes and aquatic habitats and contribute to downstream flooding. Green infrastructure captures and filters pollutants by passing stormwater through soils and retaining it on site. Effective green infrastructure tools and techniques include green roofs, permeable materials, alternative designs for streets and buildings, trees, rain gardens and rain harvesting systems.

As part of the strategy, EPA will work with partners including local governments, watershed groups, tribes and others in 10 cities that have utilized green infrastructure and have plans for additional projects. EPA will encourage and support expanded use of green infrastructure in these cities and highlight them as models for other municipalities around the country. The 10 cities are: Austin, Texas; Boston, Mass.; Cleveland, Ohio; Denver, Colo.; Jacksonville, Fla.; Kansas City, Mo.; Los Angeles, Calif.; Puyallup, Wash.; Syracuse, N.Y.; and Washington, DC and neighboring Anacostia Watershed communities.

Energy savings is one of the greatest benefits of green infrastructure. On and around buildings, green infrastructure can reduce heating and cooling costs. For example, green roofs reduce a building’s energy costs by 10 to 15 percent, and an additional 10 percent of urban tree canopy can provide 5 to 10 percent energy savings from shading and windblocking. Green infrastructure also conserves energy by reducing the amount of stormwater entering combined collection and treatment systems, which reduces the amount of wastewater processed at treatment plants.

EPA will continue to work with other federal agencies, state and local governments, tribes, municipalities, and the private sector to identify opportunities for using green infrastructure and provide assistance to communities implementing green approaches to control stormwater. EPA will also provide additional tools to help states and communities leverage green infrastructure opportunities within other innovative environmental projects.

For more information on EPA’s green infrastructure agenda: http://epa.gov/greeninfrastructure

Green Roof for Tulsa City-County Central Library!

The Tulsa City-County Central Library, constructed in 1965, formerly included two reflecting pools flanking the main library entrance.  The reflecting pools were built over an underground parking structure - and over time -the pools began to leak, damaging cars and creating a hazard.  And so, the pools were emptied and sat abandoned for years.  They became an eyesore, and a maintenance issue. 

The library evaluate using the former pools as landscaping, but faced challenges due to soil loads on the parking structure roof.  But, observing rooftop gardens, they began to see other opportunities for reuse. 

After consultation with structural engineers, the library confirmed that a roof system would be feasible.  The project was fully funded by the American Recovery and Reinvestment Act "Green Project Reserve" adminstered by the Oklahoma Water Resources Board. 

The first step was to remove the old terrazzo and install a new waterproof membrane to correct leakage problems.  The next step was to add insulation and a root-stop barrier.  The bottom white later is styrofoam insulation, which was also helped to raise the bed.

Next, a moisture retention layer was added.  This was critical due to the long, hot, dry summer in Tulsa as well as the garden's location on a southern exposure.  Roof top gardens often also have moisture loss from constant winds.  Rather than using soil, LiteTop(r) growing media was utilized to help minimize weight. 

Plants were chosen to minimize the need for irrigation and maintenance.  A drip irrigation system was installed to assure plant survival while minimizing water consumption.  The landscaping design was developed specifically to deter misuse or vandalism of the beds.  The final installation is an attractive as well as educational addition to the library.  Along with overall beautification, the library has seen a decrease in the amount of abuse and litter in the surrounding plaza.