Bad weather can be a test, as many of us know, and it appears that the torrential rains tht deluged Washington on Monday morning provided a test of the value of all the tunneling that has been going on for months beneath our feet.

According to the District’s water utility, the first section of its Anacostia River Tunnel System did its job. It kept about 170 million gallons of combined sewage and stormwater from gushing into the Anacostia River, said DC Water.

Late last month, the utility began operating the first section of the system, running from RFK Stadium to the Blue Plains Advanced Wastewater Treatment Plant.

It was not long, it appeared, before it got a trial in true storm conditions.

About two inches of rain fell at Reagan National Airport in about three hours early Monday.

That amount was “far more,” the utility said, than the city’s system of combined storm and sanitary sewers could handle.

But said DC Water’s interim CEO and general manager, the system worked as designed.

While the rain poured onto city pavements, and rushed into sewers, the system was storing – then treating—millions of gallons of combined sewage that otherwise would have overflowed to the river.

“That is great news for the Anacostia,” Brown said in a statement, “and it will only get better when the rest of the tunnel system is brought online.”

According to the utility, the part of the system that was placed into operation includes about seven miles of tunnel with an inside diameter of 23 feet. It can store, the utility said, more than 100 million gallons, while “ continuously processing another 225 million gallons per day” at the new Wet Weather Treatment Facility at Blue Plains.