A Continuous Flow-Through Water Quality Monitoring Systems for Highway Stormwater Management

Focus Area

Water Quality/Wetlands


Natural Resources






1-2 years

Research Idea Scope

Efficient and effective water-quality monitoring is key
to understanding and setting water-quality objectives and meeting local, state,
and federal stormwater regulations. Inaccurate representation of contaminants
in urban runoff can lead to the design of under- or over-sized BMPs, rendering
them either ineffective or unnecessarily costly. Current methods for collecting
and transporting samples are time-consuming, expensive, and sometimes
dangerous.  Accurate monitoring of
stormwater pollutants is difficult to accomplish, especially in regards to
short-lived and erratic storm events. 


The objective of this project is to further improve a
prototype system developed by U.S. Geological Survey for autonomous and
self-sustained water quality sensing and to demonstrate it for field monitoring
of water quality near a highway.


The innovation in the project lies in the coupling of
depth-integrated, automated water-quality samplers with flow-through monitoring
systems at select highway outfalls as a means to develop real-time measurements
of sediment and sediment-associated constituent concentrations. The U.S.
Geological Survey has already developed a new depth-integrated sampler arm
(DISA) to reduce solids stratification bias commonly found in urban runoff


Continuous water-quality sensors have been on the market
for several years and are readily available. While these devices work well in
open channel environments, they are generally not designed for use in closed
conduits such as storm sewers. A flow-through system could alleviate that
limitation. The research proposed will apply these combined technologies as a
way to help DOTS meet future water quality monitoring needs at storm sewer

Urgency and Payoff

This research is urgently needed in light of the increasingly
stringent environmental regulations related to water quality. The autonomous
feature of the system minimizes the need for frequent manual sampling and
testing, a time-consuming, costly, and sometimes dangerous task. Also, the in
situ features of the system will enable near-real-time monitoring of water
quality, and minimize the possibility of missing short-lived events due to the
need to collect water samples.  Such
near-real-time data on water quality at distributed locations along highways
will enable DOTs in early detection and prompt mitigation of toxins and
pollutants in highway runoff. Finally, the system provides DOTs an efficient
tool to identify seasonal trends in selected parameters of water quality along
highways, to assess the impact of various highway activities on the water
quality, and to evaluate the performance of various highway-runoff BMPs over
time.  Deploying such systems may
initially require a high capital investment but in the long term, cost savings
will be significant as this equipment minimizes laboratory costs and labor
hours required for more traditional water quality monitoring. 

Suggested By

Xianming Shi & Bill Selbig Western Transportation Institute & USGS Wisconsin Water Science Center 406-994-6846

[email protected]