Catch Basins

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Q: What is a catch basin?

A: A catch basin is a curbside receptacle whose function is to convey water from streets and other urban surfaces into the storm drain system. The design of this drainage structure includes a sump that captures and temporarily stores some pollutants such as oils and sediment. Regular maintenance to clean out the sump removes the stored pollutants and prevents them from washing further into the storm drain system and into receiving waters such as the Truckee River.

Q: Are sewers and storm drains the same thing?

A: No. They are two completely separate systems. The sewer system, also known as the sanitary sewer or wastewater sewage system, conveys household, commercial and industrial wastewater through a separate plumbing system into an underground sewer pipe system. Wastewater in the sanitary sewer system is from sources such as water and waste from sinks, toilets, washers, and car washes, to name but a few. Discharges to the sanitary sewer system receive extensive treatment and filtration at wastewater treatment plants, such as the Truckee Meadows Water Reclamation Facility, prior to being discharged into the Truckee River. The storm drain system on the other hand, receives only limited or no treatment, and discharges directly into the Truckee River or other water basins such as Silver Lake or Lemmon Lake untreated.

Storm Drain System

 

Q: Do catch basins and storm drains get cleaned out?

A: Yes. Within the Truckee Meadows, there are over 9,100 catch basins that are cleaned at least twice a year with vacuum trucks. There are a number of problematic locations throughout the area where certain catch basins, because of either location or repeated illegal dumping, are cleaned more frequently. Currently storm drainpipe maintenance in the area varies between jurisdictions. The City of Sparks hydro-flushes their entire storm drainpipe system annually. Whereas the City of Reno and Washoe County clean their storm drain pipe systems on a complaint driven or problem area basis. Open ditches and detention basins are also part of the areas storm drain system. These facilities are routinely checked and cleaned of weeds, trash, debris and rodents at least once a year.

Q: Can catch basins be cleaned out right before a storm?

A: Some catch basins with noted clogging or illegal dumping problems can be cleaned with vacuum trucks prior to forecasted storm events. However, with over 9,100 catch basins in the Truckee Meadows, it's not possible to clean out all of the catch basins before the rain begins to fall. There are just too many catch basins and not enough resources or crews to make sure all of them are clean before every storm.

Q: What kinds of pollutants are found in the storm drain system?

A: Paint thinner and paint products, used motor oil and antifreeze, pesticides and fertilizers, sediments containing heavy metals, styrofoam cups and paper trash, human and animal feces, golf balls, dirty diapers, and dead animals are but a few of the pollutants found in the system on a daily basis.

Q: Can filters or screens be installed in front of catch basins?

A: It sounds like a good idea. But during a rainstorm, leaves and trash in the streets are quickly swept into catch basins. Filters or screens installed in front of catch basins could cause leaves and trash to accumulate and clog the grate, preventing proper drainage and causing flooding hazards.Temporary filters or screens are sometimes placed in front of catch basins located near construction sites. These structures are also known as Best Management Practices (BMPs) and are required in some communities to prevent sediment and construction site wastes from entering the storm drain system. Ponding will occur at protected catch basins causing possible short-term flooding hazards. There are new technologies being developed in the form of filtration or screening devices that can be installed and inserted inside catch basins. The Truckee Meadows Interlocal Stormwater Committee is currently evaluating these new technologies for consideration.

Q: Why doesn't the County build a regional stormwater treatment facility?

A: Such a facility would be extremely costly to build and maintain. The huge volume of water produced by even a modest rainstorm would require a gigantic facility. However, this program proposes to build numerous relatively small stormwater treatment structures to capture and filter pollutants transported in runoff.

Q: How much water passes through the storm drain system?

A: In urban areas where much of the natural surface has been replaced by pavement and buildings, the majority of the water from storms runs off these hard surfaces and flows into and through the storm drain system. In addition, dry weather flows from individuals washing their cars, draining their pools and over-watering their lawns, to name but a few activities, also flows into the storm drain system. On a typical dry summer day, watering and washing activities can produce hundreds of thousands of gallons of water draining into the system and eventually into the Truckee River. During a heavy rainstorm, this flow can increase to millions or even billions of gallons.