Stabilizing Steep Stream Ravine Systems to Protect Residential Infrastructure
Emily Poynter Jenkins, PhD, PE, CFM
Farnsworth Group, Inc.
Champaign, IL
Several ravine systems in Danville, Illinois can be characterized by steep slopes and sandy soils that are fed mostly through stormwater. As such, four ravines were experiencing severe erosion to the point of threatening residential infrastructure like decks, sheds, and fences. Farnsworth Group was approached by the City of Danville to stabilize the ravines and protect the surrounding infrastructure.
Several challenges presented themselves throughout the design and construction phases, including stakeholder buy-in, project constructability, as well as the technical hydraulic design. The areas of the ravines are highly residential with many cul-de-sacs. Any design had to ensure access to all houses at all times, so installing culverts or pipes across roadways would need to include a carefully crafted traffic plan. The stakeholder outreach was substantial in this project; many residents were approached individually for temporary and permanent easements for the work. Some portions of the project and early concept designs were abandoned due to the inability to secure an easement on the property. Additionally, some residents upstream of unstable ravines did not want any improvements in their portion of the stream, rendering useless ideas to slow the water in the upper reaches, like infiltration basins.
The ravines have very steep sides and there are very limited access points between houses to gain access to the ravines for construction. As Farnsworth Group began the project, we designed everything with constructability in the forefront of our minds. In this presentation, we will discuss a few of the tangible ways we prepared for construction of the projects.
Finally, the technical design of the ravines with the existing constraints made for an interesting project. The basis of design is two-fold: reduce water velocities by encouraging infiltration and dissipating energy. With the sandy soils present, the ravine systems have high infiltration rates if the water can be held momentarily in infiltration basins or step pools. Additionally, our designs also utilize plunge pools and drop structures in manholes to dissipate energy in the ravines. The ravines construction are scheduled to be finished in early Summer 2026.
About Emily Poynter Jenkins, PhD, PE, CFM
Dr. Emily Poynter Jenkins is the Water Resources Group Lead and Champaign, Illinois Civil Engineering Manager at Farnsworth Group. Dr. Jenkins specializes in sustainable and ecological designs to manage stormwater and improve water quality, such as stream restorations and bank stabilizations, green infrastructure, and multi-functional stormwater detention. Other projects of hers include modeling rivers and storm sewers, assisting clients with development of stormwater master plans and rainwater management programs, and restoring ecosystems, such as wetlands and floodplains, to protect river health. Prior to Farnsworth Group, Dr. Jenkins worked at the Illinois State Water Survey, where she was a contributing author of the Illinois Model Ordinance for municipalities, and at private consulting firms within the Chesapeake Bay watershed to reduce sedimentation and improve water quality of the Bay. She earned a Civil Engineering degree from the University of Illinois at Urbana-Champaign (B.S.), an Ecological Engineering degree from the University of Maryland (M.S.), and a Ph.D. in Agricultural and Biological Engineering from the University of Illinois. Dr. Jenkins was a Forty under 40 recipient in Champaign County in 2021 and was recently appointed by the IL governor to the Ohio River Valley Water Sanitation Commission (ORSANCO).