TERRA Engineering, Ltd. provided construction documents for an innovative “pilot project” that included approximately 8 square blocks of new streets and alleys consisting of nearly 2.0 miles of street and alley improvements. The project was labeled a “pilot project” because it incorporated a new green alley concept, proposed and designed by TERRA. TERRA was also the landscape and civil engineer for the land development on the properties adjacent to the right-of-way improvements. This allowed for an opportunity to evaluate the overall development and utilities in the area to provide a design that both would best benefit the municipality’s and future residents interests.

In addition to the new streets and alleys for the residential development, the redevelopment had very few available utilities. New sewer mains, water mains, electrical services, and telecom lines were routed throughout the site to feed the future residences. The improvements also included new street lighting, updated accessibility ramps and sidewalks, and landscaped parkways.

The land development project consisted of individual residential lots that would typically not require detention due to the size of each of the properties. In an effort to protect residents from flooding or other problems stemming from a sewer system at near capacity, and recognizing the potential offend by the porosity of the underlying soils TERRA proposed providing detention for the individual residences in a proposed green alley system. The system is ultimately maintenance free for the city and requires only minimal maintenance for the residences. While protecting the City from liability, the system reduces the capacity stress of the sewer, and provides superior protection for each resident by reducing flow to the combined sewers; the concept also reduces the City’s treatment costs.


Chicago Department of Transportation