Making It Work on the Waterfront

By Ken Kastman, PE

We all like water. Who doesn’t enjoy sipping coffee, tea or wine on a veranda overlooking a river? But, what if the river is dark, brown, stagnant and has a pungent odor … the common state of many urban rivers in areas of brownfield redevelopment?

Restoration of water aesthetics is essential to riverfront redevelopments, but often raises difficult technical issues:

• What cleanup is necessary, and how is it best accomplished?
• Whose contamination is it? (Contaminants can enter the water from many sources and can travel downstream with the sediments.)
• Who pays for cleanup? (Many times the property stops at the water’s edge and the state owns the water.)

Sediment Management

The U.S. Army Corps of Engineers estimates there are tens of millions of tons of sediments clogging our waterways. The U.S. EPA Great Lakes Program Office estimates that some 340,000 cubic yards of sediments have been remediated at 36 sites within the Great Lakes basin alone from 1997 through 2004. Sources of sediments include stormwater flow from city streets and erosion from farm fields. Sediments can consist of fine-grained clays, silts or coarser sandy materials.

The physical characteristics (e.g., grain size, water content, solids content and organic content) of the dredged sediments become critical and there are numerous techniques to handle sediments efficiently. The most common techniques for dealing with sediments are capping them in place or dredging them and placing them in an upland disposal area, typically in a landfill or a confined disposal facility (CDF).

Most of the time the CDF is located adjacent to the water body and the sediments can be hydraulically dredged and pumped to the facility.  At other times, the CDF may be away from the water, and the sediments need to be transported to the facility. However, none of the techniques is particularly cost effective when dealing with large quantities of materials, even if the sediments are not contaminated.

One recent innovative solution, called “Mud to Parks,” dredged a section of the Illinois River near Peoria, Illinois, and barged the sediments to Chicago to create cover soils for a new city park on a brownfield site.

Contamination Cleanup

Not all sediments are contaminated, although most have some level of constituents not normally found in natural river deposits. People tend to think that the contamination is typically from industrial pollutants, and historically this was certainly true. With more active industrial outfall control and water management programs starting in the 1960s, many rivers have become
cleaner through natural cleansing (i.e., natural biodegradation processes) and lower levels of constituents being allowed to enter the water. That is not to say that the problem is going away, but is headed in the right direction.

Today, contamination is more likely a result of the remaining combined sewer overflows, non-point source inputs (particularly in agricultural areas), and in some cases, natural causes like urban geese. Hot spot removal and disposal, chemical stabilization and land farming (i.e., to promote biodegradation) are some remediation techniques. But again, none of these solutions are particularly low-cost.
 
Who Pays?

Financing for a brownfield cleanup often involves cobbling together various sources of funding. The Great Lakes National Program Office and U.S. Army Corps of Engineers sponsor and track active river rehabilitation programs, and many states have some cleanup dollars available under their water-related programs. Most likely, the rest of the cleanup dollars need to be calculated into the property redevelopment costs and anticipated in the pro-forma at the strategic development decision phase of a project. 

There are no simple or low-cost solutions. However, unique solutions can be found, such as using stabilized sediments as cover or under parking areas, creating constructed wetlands, or placing innovative edge plantings to keep geese away from the water. Owners should challenge their consultants and regulators to solve the issues in a way that blends into the remediation. BFN

Ken Kastman is a vice president and senior principal engineer at URS Corporation in Chicago. He is the leader of the URS Property Redevelopment Network.