Local storm water managers are often in need of quantifiable information to meet mandatory storm water permit requirements or to justify their storm water management budgets. Monitoring to track the effectiveness of local storm water programs is one of the best ways to collect such information, such as determining what pollutants need to be targeted, identifying the sources of pollutants and demonstrating which practices can best control pollutant sources.
Phase I National Pollutant Discharge Elimination System (NPDES) municipal separate storm sewer system (MS4) localities already are required to conduct monitoring, but they often find that trying to quantify the impact of MS4 storm water program activities can be challenging and expensive. Municipalities that fall under the Phase II NPDES storm water regulations are required to meet six measurable goals, including public education/outreach and construction site sediment and erosion control. Typically, the measurable goals are output-based (e.g., number of storm water treatment practices installed, number of educational brochures distributed), which is useful from a program accounting standpoint but does not allow changes in water quality as a result of these activities to be quantified.
As part of a U.S. Environmental Protection Agency grant, the Center for Watershed Protection and the University of Alabama prepared six monitoring study designs, outlined in the project's final manual, Monitoring to Demonstrate Environmental Results: Guidance to Develop Local Stormwater Monitoring Studies Using 6 Example Study Designs. This guidance is designed to navigate storm water managers through the complexities of implementing a monitoring program so they can be confident in their results and get the most out of their limited storm water dollars. The six study designs address the following questions:
What is the quality of the storm water at the outfall?
What are the sources of pollutants in storm water?
What is the effectiveness of individual storm water treatment practices in reducing pollutants?
Do implementation and maintenance factors affect storm water treatment practice function over time?
What is the effect of public education programs on water quality?
What is the cumulative effect of treatment within a watershed?
Each study design covers such essential elements as scoping, budgeting and staffing needs as well as equipment and sampling requirements. Special issues associated with each monitoring study design are also covered for those unforeseen but inevitable monitoring challenges.
This manual is available for free download from the Center for Watershed Protection's website, www.cwp.org.
