State Water Resources Research Institute Program
Project ID: 2009PA98B
Title: Stream Storm Flow Dynamics Below Combined Sewer Systems: Human and Runoff Inputs
Project Type: Research
Start Date: 3/01/2009
End Date: 2/28/2010
Congressional District: 14th
Focus Categories: Water Quality, Hydrology, Surface Water
Keywords: hydrology, water
Principal Investigator: Bain, Daniel (University of Pittsburgh)
Federal Funds: $ 17,500
Non-Federal Matching Funds: $ 35,977
Abstract: Urban areas in Western Pennsylvania and across the United States have inherited a legacy of sewer systems specifically designed to overflow during wet weather periods. These systems intentionally route large quantities of contaminated water to local waterways. Recent regulatory activity is spurring a concerted effort in Western Pennsylvania to eliminate these overflows, necessitating either treatment of large volumes of water or reduction of storm flow in these systems. However, strategic decision making is hampered by limited data on specific hydrologic flow paths and sources.
In addition, the rehabilitation and restoration of fluvial ecosystems is an emerging option in the management of water quality. Pittsburgh's Nine Mile Run has been physically rehabilitated in the hopes of recreating a healthy fluvial system within the city limits. However, while many stream restoration projects are not evaluated following installation, a comprehensive data set on chemical, biological, and physical features is being collected in Nine Mile Run. This sort of monitoring information is vital to the successful utilization of stream restoration as a landscape management tool.
The proposed research will address both information needs by developing an urban hydrologic tracer from fluoride (F) added to domestic drinking water. As mineral sources of F are rare, F observed in the system can be assumed to originate from domestic water sources, providing a method to quantify the contribution of domestic water to surface water systems. While preliminary data is promising, this technique must be evaluated rigorously before it can be applied more widely.
Further, fluoride is particularly promising as a relatively inexpensive high temporal resolution tracer due to relatively stable and robust ion selective electrode technology developed for water treatment and other production facilities. Transfer of F ion selective electrode technology to urban streams should allow for unprecedented information on F content in these waters, and when coupled with emerging low cost temperature loggers, unprecedented information on urban hydrologic source and pathway.
In Nine Mile Run, F tracers, quantified using logged information from ion selective electrodes, should allow hydrograph separation into domestic water and other water. This separation will be essential in the evaluation of the contribution of human activity to flow dynamics in urban systems. For example, storm hydrographs from Nine Mile Run that span the early morning period contain secondary peak structures between six and nine am, a period of substantial human waste water production. Do these peaks reflect human inputs which extend and exacerbate overflow conditions? If so, can we utilize this information to ameliorate overflow conditions through peak flow pricing or other strategies?
In summary, the proposed research will develop F as a hydrologic tracer for urban systems and apply that tracer to Nine Mile Run, a restored urban stream system. These efforts will provide novel data on urban hydrologic flow paths and the efficacy of restored urban systems, addressing information gaps and therefore improving our ability to strategically address contemporary water quality problems.
Progress/Completion Report, 2009, PDF