Spring 2020 brought plenty of rain and sunshine to Wetland Studies and Solutions, Inc.’s (WSSI) Gainesville, Virginia office, and our CU-Structural Soil® patio. In October 2018 we renovated the patio at our LEED-Gold certified headquarters, using this engineered soil blend to provide stormwater mitigation and support tree root growth. This sustainable feature joined many others that we have implemented on our grounds, and we are happy to report on its effectiveness.


We effectively created a mini laboratory so we could see this new green technology in action, adding sensors in monitoring wells so we could understand how rapidly water moves through the CU-Structural Soil® system to the groundwater below. The data show that the CU-Structural Soil® patio at WSSI has never had any stormwater runoff. Instead, all of the water that has fallen in the patio footprint has infiltrated into ground water, absorbing nitrogen and phosphorus along the way and providing water for the trees planted there. We would expect similar results for anywhere CU-Structural Soil® is used over or adjacent to permeable soils.


The Emerald Sunshine Elm (Ulmus propinqua ‘JFS-Bieberich’) trees installed in the patio are now in their second growing season, and new, healthy leaves and sprouts attest to their good health. They have overcome the typical transplant shock they experienced in their first growing season.  We will continue to monitor the tree growth, using ground-penetrating radar (GPR) to evaluate root spread.  We also could dig in to the soil to directly measure root volume.

Looking for the data analysis?
Click here.

We’ll Keep Watching

WSSI will continue to monitor the installation for years to come.  If you would like to know more about our patio or have questions about this alternative soil media for low impact development, please check our October 2018 seminar page, or contact Dillon Conner and Frank Graziano of WSSI, or Chris Fields-Johnson of The Davey Institute.

We built our LEED-Gold Certified headquarters office in 2005 to showcase innovative design and sustainability practices. WSSI’s applied research – here and with wetland, stream, and ecosystem restoration – is important to us for advancing the state of the science that helps balance land development with environmental stewardship.


  • Dillon Conner, PLA, ISA Certified Arborist

    Gainesville, VA

  • Frank Graziano, PE

    Gainesville, VA

  • Chris Fields-Johnson, PhD, ISA Certified Arborist, TRAQ

    Gainesville, VA