Stormwater Infrastructure
Arlington works to upgrade and maintain its stormwater infrastructure, reduce flood risks and help private property owners learn more about their flood risk.
When it rains, stormwater flows through Arlington's drainage system, which includes:
- 10,000 storm drains
- 373 miles of storm sewers
- Approximately 1,000 outfalls - where stormwater leaves the storm sewers and flows into open channels and streams
- 33 miles of open channels and streams.
Through the course of development, more than half of Arlington's original streams were replaced by a system of underground storm sewer pipes. Rain water in the storm sewer system is discharged to Four Mile Run, other Arlington streams, or the Potomac River.
Most storm sewers in Arlington County are reinforced concrete, corrugated metal or terra cotta. Most of the collection system has been inspected over the past 12 years and is in good condition, with repairs, replacements and rehabilitation implemented as necessary. Reinforced concrete pipes typically have a life span of 75–100 years, and rehabilitation can increase the life span another 25–40 years. Corrugated metal and terra cotta pipes have a significantly shorter life span, and therefore, pipes made of these materials are being proactively replaced with pipes made of reinforced concrete.
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