Credit: Photo by Steve Bohnel

At first glance, it doesn’t appear like much: a small gray box with some solar panels on a metal pole with a wire stretching down into Gunners Lake in Germantown.

But for Montgomery County and state officials, this flood sensor is one of 35 sensors that will be installed countywide by August, helping monitor when future flooding might occur, according to county officials. 

They will collect data and help pinpoint where there are quick increases and decreases in water levels in lakes, stormwater retention ponds and other areas countywide.

The federal Department of Homeland Security paid for sensors, officials said. Each sensor costs about $3,500 and the federal government will also cover the first two years of operating expenses, according to Jeff Booth, Sensors and Platforms Technology Center Director for DHS.

The sensors are expected to last about 10 years, he added.

Matt Miziorko, a specialist with the county’s Office of Emergency Management and Homeland Security, said that once the sensors are installed, they will be able to send notifications within 30 seconds that water levels are rising or falling at a given location. 


In an interview, Miziorko said the sensors are solar-powered and installed on poles. A wire runs down the pole to a device in the water. The device can measure water levels, including how quickly they are rising and falling, he said. 

That data is then sent to the Office of Emergency Management and Homeland Security, Montgomery County Fire & Rescue Service, Department of Transportation and other county officials if certain levels are reached, Miziorko said.

“What we’re always concerned about is if there’s a sharp rise, or a sharp decrease [in water levels],” Miziorko said. “A sharp rise is usually indicative of flash flooding — you have to get someone out there quickly if there’s a road. If it’s a sharp rise and it’s a dam, we have to get somebody down here to start physically monitoring the site.” 


“If it’s a sharp decrease, that’s a good thing if it’s on a road, because we can clean it up and open it back up, [but] if there’s a sharp decrease on something like a dam, that may mean there’s a hole developing and we have to begin evacuations.”

County officials demonstrated how the sensors would work at Gunners Lake on Friday and described how the program would work countywide. The sensors would be located at various points countywide, including at Rock Creek Woods Apartments near Rockville — where Melkin Cedillo, 19, died in severe flooding last year

Chris Conklin, director of the county’s Department of Transportation, and county Fire Chief Scott Goldstein said the sensors will help alert them and colleagues about where problem areas could arise. 


Goldstein reminded county residents not to drive into standing water. Six to eight inches of rushing water can knock down a person and less than a foot can displace a light vehicle, he said. 

Employing the sensors will help prevent such occurrences because county officials can shut down roads or other areas that become impassable, he said.

“This is a perfect tool for us, as a community, as a whole, to prevent the 911 call” for swift water rescues and other flooding emergencies, Goldstein said.


How might the sensors determine what infrastructure improvements are needed? 

County Executive Marc Elrich said at Friday’s news briefing that the sensors will help county officials keep track of potential flooding areas, especially as climate change is expected to cause rising temperatures and increased rainfall in the coming years.

In an interview, he said county officials are currently reviewing all drainage basins and areas that might be more flood prone. It’s important, however, to review how roads, streams and the natural environment all interconnect before county officials try to improve infrastructure to prevent further damage from flooding, he said. 


“We want to be able to put ourselves in a position to understand the hydrology of the area, to see what’s causing it, so that we can actually fix it,” Elrich said. 

Fixing infrastructure issues without addressing the wider, root causes of flooding wouldn’t be cost-effective, he added.

Adriana Hochberg, acting director of the county’s Department of Environmental Protection and the county’s climate change officer, led Friday’s news briefing. She said in an interview that county officials are gathering baseline data about historical flooding and how various county departments respond to those incidents.


Hochberg said the research and data collection — which will include information provided by the sensors — can help officials determine what regulatory or legislative changes are needed, along with future infrastructure projects.

It’s too early to say exactly what changes might be needed, but there are some broad proposals, she said.

“An example might be that with climate change, what is currently considered a 100-year-storm, those numbers are all going to change in the future,” Hochberg said. “And so perhaps, our regulatory structure needs to be more flexible, so that design standards can ramp up [and] those numbers can change over time to accommodate the changes that are happening in the climate around us. Right now, things are fixed in time, based on pre-climate change conditions.”


Miziorko said the placement of the water sensors was determined by looking at data from the National Weather Service and the county’s 911 dispatch center and seeing where common flood areas have occurred during the last two or three decades.

The sensors will be helpful in determining where a road might need to be raised by a couple of inches or where a bridge might need to be widened in order to prevent future flooding, he added. 

Booth said the sensors are examples of new devices that are in the realm of technology that connects to communications networks, and help informs officials via the exchange of information over those networks. 


There’s been such an explosion in that type of technology that residents may soon be able to purchase sensors to plug into their home security system in order to monitor future flooding. And insurance companies will want to take advantage of that, he added.

“They should see the benefit of homeowners knowing when a [flooding] event is coming, or what to do to prevent some of the damages that might occur,” Booth said. “That’s kind of where I see some of this technology going.”

Steve Bohnel can be reached at