Stories from DEP is a collection of feature articles
published in DEP's internal newsletter, Weekly Pipeline.
This article was originally published April 19, 2011.
They’re G-r-r-r-r-ate! Catch Basin Crews Storm City’s Drains
For most New Yorkers, it’s just another feature of the urban landscape — barely acknowledged until a ring or an iPhone is dropped down the ominous metal grate. While catch basins may not be the most glamorous piece of infrastructure, they perform a critical role in ensuring the health, safety, and economic vitality of New York City.
A catch basin is a type of storm drain located adjacent to a curb that collects rainwater from the street and transports it either to one of DEP’s 14 wastewater treatment plants (for combined sewers) or directly into a waterbody (for stormwater sewers). The catch basin is typically covered by a metal grate, which prevents large objects from falling in. Catch basins function primarily as a draining mechanism during heavy storms to prevent flooding and allow rainwater to flow off of the city’s impermeable streets and sidewalks. With more than 144,000 catch basins, some of them are bound to get clogged once in a while.
To ensure clogged catch basins are a rare occurrence, BWSO’s field operations unit carries out a comprehensive catch basin inspection program which ensures that each of the catch basins is inspected at least once every three years. BWSO also responds to 311 complaints regarding clogged catch basins and street flooding, and a special rain patrol is also sent out during heavy storms to focus on clearing debris off the top of catch basins. When a weather event is forecast, crews also preinspect areas prone to flooding to ensure infrastructure is operating properly.
During a scheduled inspection, BWSO staff examines the surrounding concrete, sidewalk, and the iron grate itself to ensure that there are no structural issues. Next, they measure the accumulation of debris in the catch basin to determine if cleaning is required. Anytime the level of debris in a catch basin comes within 18 inches of the outlet to the sewer system, a cleaning is required. To clean the catch basin, BWSO uses a truck mounted crane, which first lifts the metal grate off of the catch basin and then uses a clamshell bucket to remove the debris.
When you inspect so many catch basins each year, you’re bound to make some unexpected discoveries. According to Dennis Delaney, Chief of Maintenance and Repairs for the Bronx, Manhattan, and Staten Island, his crews have found raccoons, swans, and baby ducks living in catch basins. His crew was even called on recently to rescue a small kitten that had fallen through the metal grate and down into the catch basin. BWSO also occasionally receives calls from the NYPD to assist in a weapon search when it is believed that a suspect dumped a gun or knife into a catch basin.
Although sewer maintenance crews are happy to help with the rescue of a kitten or even a lost iPhone, their primary responsibility is always to ensure the overall integrity of the sewer system. And catch basin cleaning remains a critical sewer maintenance activity. Rick Nelson, the Acting Chief of Maintenance and Repairs for Brooklyn and Queens, points out that by reducing the likelihood of flooding, catch basin cleaning “ensures the health, security, and well-being of the general public.” So the next time you’re walking down the street, take a moment to notice the catch basins beneath your feet and the thousands of miles of connecting sewers that make it possible to live comfortably in New York City.