Water, Water, Everywhere, But Where Is It All Going: Three Tips for Watershed Scale Stormwater Monitoring

Effectively monitoring stormwater management systems can be difficult, especially if you intend to look beyond a single project and piece together a bigger picture. As more regions are adopting TMDL programs, updating SWMM models, and preparing for climate change, it’s becoming apparent that regional scale data is a necessity. Here, we share three tips for effective watershed-scale stormwater monitoring:

(1) Use a Control

This is the first rule of every scientific study, right? You’d think—but due to budget and/or timing constraints, this portion of the study is often the first to be cut. For watershed-scale projects, finding a proper control can be tricky. The go-to method of using pre-construction comparisons is often not possible when we are talking about a large area with multiple stormwater projects. If you’re lucky, there may be published pre-development data for your region.  U.S. EPA’s  water quality portal is a good place to look for that information. If you’re not so lucky, one approach that can work well is the use of a reference watershed. An undeveloped area that is close in proximity and is similar in size, topography, and climate to the one in your study is a good choice for a reference.

Example: The Consortium of Universities for the Advancement of Hydrologic Science has provided a  Webinar that gives a detailed explanation of how to use this method for a multiple watershed approach.

(2) Utilize Established Data Networks

Watershed scale monitoring requires “eyes” everywhere. That can get complicated (and expensive!) really fast. While collecting as much targeted data as possible is a great goal, it’s also great to be aware of the data networks you can use to supplement your efforts. The National weather service provides current and historic precipitation data that can be easily downloaded and correlated with field measurements. In a coastal area? Pull your local tide records from NOAA.  Inland? Grab your local stream or well data from USGS.


Example: A recent study in Baltimore, MD was among the first to quantify the effects of Green infrastructure on a watershed scale. They were able to do this by relying heavily on a network of USGS stream gauges in addition to the data and field measurements they collected.

(3) Integrate Real-time Data

One of the newest technologies to enter the stormwater sphere is real-time data access. This form of information can be especially useful when monitoring on the watershed scale. Your test watershed most likely has several types development and stormwater controls. In the past, researchers had to wait until a storm was over to download data and determine how BMPs had performed, and this was usually done on a project by project basis.  Now, it is possible to know in real time during a storm event where pipes are filling up fastest, where overflows are occurring most often, and where systems are functioning most smoothly. This knowledge can help close the loop and link effects you’re seeing downstream to specific upstream controls, which allows you to better prioritize future stormwater management efforts.


At StormSensor, our focus is on providing real-time, regional scale stormwater data. We are able to do this within almost anyone’s budget because we have developed our own sensors that are priced in such a way to allow for watershed-scale deployment. Our sensors, called Scutes™, track water level, temperature, and velocity within the pipe.  All of our data is cloud-based and immediately accessible via our dashboard. Our software also pulls hyper-local weather data to correlate with sensor measurements.  We are currently developing machine-learning algorithms to learn baseline flows and detect and quantify events such as overflows, illicit discharges, and storm surges. Contact us if you are interested in learning more about how StormSensor could work in your watershed!

About the author

Suzie Housley

Suzie sees her role in the stormwater world as a “go between” the technical and the general communities. She uses her years of experience to decipher scientific studies and government policies to communicate a practical message.