Green Infrastructure, Standing The Test Of Time

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Long before the buzz to use green infrastructure began, Craig Cawrse, CT Consultant’s Director of Landscape Architecture, had been using and evaluating the benefits of these techniques and their use on his projects. Craig saw how other regions of the world used pervious pavements and other green infrastructure techniques in their designs and realized the environmental and storm water management benefits of employing such techniques. Thus began his desire to be an early champion for taking a more natural approach to land development and the greening of our communities.

Aerial taken shortly after construction of new office building featuring sustainable site design.

Not only did Craig begin promoting the benefits to his clients and peers, but he took it one step further and really owned it. He made a financial commitment and a statement to the industry by developing the site for his new office building in a sustainable manner using eco-friendly LEED principles 13 years ago. These principles sought to restore and retain the natural systems through a design that was conscientious of the natural environ. This included a storm water treatment train using a combination of permeable pavers, a rain garden, a bio-swale, and bio retention.

Site features included:

  • Permeable pavers to reduce runoff through infiltration; an underdrain system under the pavers drains water to an outlet on the east side of the parking area to the vegetated swale.
  • A rain garden that captures a portion of the roof runoff and allows for infiltration and uptake by plants.
  • Vegetated swale which reduces flows and increases infiltration of runoff from the parking area underdrain and a portion of the roof.
  • A storm water pond or wet-extended detention pond that reduces runoff and increases water quality using wetland plants and special soil mixes.
  • Pervious Pavers

 

USGS Monitoring Equipment

The Chagrin River Watershed Partners recognized the value of Craig’s vision and awarded the project a grant to help defray the cost of the green infrastructure improvements and monitor their success/impact. This set the stage for 11 years of research and data collection. USGS installed monitoring equipment, including automatic samplers, a flow gauge, and rain gauge to track the performance of the storm water measures to address the quality and quantity of storm water impact.

For Craig and his team, it has been rewarding to experience firsthand the results of this project addressing both water quality and quantities. Highlights of the data collection to-date include:

  • Substantial reduction of storm water runoff and delayed discharge to the vegetated swale with no pollutants of concern from the pavement.
  • Maturation of green infrastructure has continued to perform well and even enhance natural flows and infiltration.
  • Phosphorus, dissolved nitrates, nitrates, and chloride levels which impact aquatic environments are below established thresholds.

This project helped to address the many misconceptions about green infrastructure. Although the initial costs are higher than traditional pavements, the long term maintenance has been minimal. The permeable pavers have held up well with a life expectancy of 30-35 years. Winter snow removal has not been an issue and contractors have not needed to adapt equipment. The permeable pavers have also reduced the amount of deicing materials applied to the pavement, further enhancing water quality to the receiving stream.

If you’re considering green infrastructure, know that when done correctly it provides long-term cost savings, measurable benefits to the surrounding environment and stands the test of time. Craig and the CT team’s expertise in sustainable design and green infrastructure within the context of site planning and landscape design also includes rain gardens, permeable paving, bio-cells, bio-swales, bio-detention, green roofs, and the use of native plant materials.

In 2018, wanting to expound on his knowledge and teach the next generation, Cawrse & Associates joined CT Consultants further adding to CT’s already deep expertise in watershed management and green infrastructure practices. At CT, with even greater depth of expertise, Craig continues to offer practical solutions for sustainable storm water management techniques, now in additional uses and applications. Craig can be reached directly at ccawrse@ctconsultants.com or 440.530.2261.

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