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Frequently Asked Questions

The City and County of Honolulu Storm Water Quality Branch receives many questions regarding storm water pollution through the Environmental Concern Line at 768-3300 and at public events. These questions range from general ones about storm water to specific topics such as area topography, types of pollutants found, and what the City is doing to combat storm water pollution. The following are some of the most commonly asked questions:

Q: What is the Clean Water Program?
A: More than 20 years ago, the federal Clean Water Act became law, prohibiting the discharge of pollutants into surface waters by private and public industries. As a result, industrial pollution of America's waters is largely a thing of the past.

But smaller amounts of pollution, much of it carried by storm water runoff, continue to harm our waters each day. This runoff is more difficult to identify and eliminate. In fact, storm water runoff may be our most severe environmental problem on Oahu. The City and County of Honolulu established the Clean Water Program to eliminate this problem.
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Q: What is NPDES?
A:
The federal government implemented the National Pollutant Discharge Elimination System (NPDES) regulations for storm water discharges to address the national problem associated with polluted runoff.

These regulations require all large U.S. cities, including Honolulu, to keep their storm drains and sewers as free of pollutants as possible. There are specific requirements for monitoring and evaluating lakes, streams, and shoreline waters. Local governments are required to educate residents and business on ways to keep waters clean.
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Q: Why is it important to use pesticides sparingly?
A:
Pesticides consist of a group of toxic organic compounds including insecticides, herbicides, fungicides and rodenticides whose presence in the aquatic environment can be particularly dangerous. Excessive application of pesticides or application shortly before a storm can result in toxic chemicals being carried from agricultural lands, construction sites, parks, golf courses, and residential lawns and gardens to ponds, streams, and near-shore waters. Many pesticide compounds are extremely toxic to aquatic organisms and can kill fish.
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Q: Why shouldn't I use a lot of fertilizer to make my yard look greener?
A:
Fertilizer, animal wastes, detergents, and organic matter such as lawn clippings, leaves and rainfall itself are all contributors to nutrient levels in urban and agriculture storm water runoff. Phosphorus and nitrogen are the principal nutrients of concern in storm water runoff.

Phosphorus especially can cause algae blooms and excessive plant growth in bays, estuaries and ponds. Decaying algae can cause foul-smelling odors in ponds and stagnant waters and may adversely affect many beneficial uses of the receiving waters, including aesthetic quality.
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Q: How does the nitrogen in fertilizers affect our environment?
A:
Organic and ammonia nitrogen in receiving waters such as streams and the ocean, undergo transformation into nitrite and nitrate through a process called "nitrification" that greatly reduces oxygen levels in the water to the point where it may kill fish. Ammonia can also harm fish and aquatic organisms. Nitrates from fertilizers and manure can seep into ground water and into the fresh water aquifer and drinking water wells, causing health problems, particularly for children. Drinking waters high in nitrate levels are known to cause "blue baby syndrome" or methemeglopbinemia, which can cause death.
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Q: Yard clippings and leaves are natural, so they don't cause problems if swept into storm drains, right?
A:
Grass, leaves and yard clippings that are repeatedly swept into catch basins can clog the drainage and cause flooding. They can also become a breeding ground for rodents and insects. Grass and leaves that enter the ocean contribute to new plant growth and lower oxygen levels, threatening fish and other organisms. For more information refer to the tips for residents and backyard conservation guide.
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Q: Why does the City stencil the storm drains with a picture of a fish and the message, "Dump No Waste - Take Care of our Ocean?"
A:
The City and County of Honolulu, as part of an interagency effort with the State, tries to minimize dumping of pollutants through this effort. Volunteers stencil storm drains with the fish and the words "DUMP NO WASTE - TAKE CARE OF OUR OCEAN" as a reminder of the harmful effects on our environment that results from careless or thoughtless dumping of pollutants into the storm drain system. Everyone is encouraged to do their part in keeping our storm water system pollution-free.
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Q: Are sanitary sewers and storm drains the same thing?
A:
No. They are two separate systems. Wastewater from homes and businesses travels through the sanitary sewer system to wastewater treatment plants, where they are treated and cleaned up before reuse or discharge into the ocean. Runoff from streets, parking lots, yards, etc. enters the storm drain system and generally receives no treatment before it flows directly to streams and out to the ocean.
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Q: What is a catch basin?
A:
A catch basin is a curbside, box-like receptacle that drains water from the street gutter to the underground storm drain pipe to prevent street flooding. There are more than 20,000 catch basins on Oahu. Each is an entry point to the storm drain system.
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Q: Why isn't a net/fence/barrier installed at the outlets of storm drain channels to collect trash?
A:The City has placed floating booms in the Ulehawa Channel in Nanakuli, principally to capture trash and debris.

It has no effect on smaller items--- bacteria from human and animal feces, or dissolved pollutants like oil, grease, pesticides, and various metals.
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Q: What kind of pollutants are found in the storm drain system? How can I be a part of the solution?
A:
Paint thinner and paint products, motor oil, pesticides, foam cups, paper products of all kinds, animal feces, antifreeze, golf balls, dirty diapers and dead animals are but a few of the pollutants found in the system on a daily basis.

As a resident, you can make a difference, both on the job and in your community. When you're at home, share your knowledge with neighbors and friends. Click here for 9 simple yet effective actions to do around the home to reduce storm water pollution.  Visit the Learning Center to learn more.

To report an illegal discharge that has already occurred or to volunteer, call the Environmental Concern Line at 768-3300 or use the online request form at www.cleanwaterhonolulu.com.

The City and County of Honolulu, working under Federal Clean Water Act Guidelines, has a number of public education programs that focus on community involvement and targeted enforcement to eliminate or reduce illegal discharge practices. Existing projects include storm drain stenciling, Adopt-A-Stream Workshops, World Water Monitoring Day, and Adopt-A-Block cleanup and monitoring program. They provide opportunities to train an interested and committed neighborhood.

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Q: Why do the channels have to be concrete? Can't they be natural waterways?
A:
Concrete channels are designed to convey large amounts of water without taking up a lot of space. Natural waterways can handle the same amount of water, but require a wider area to handle flood events.
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Q: What makes storm water runoff unique in Hawaii area?
A:
The unique characteristics of Hawaii 's topography, climate and geology result in a highly variable and complex surface hydrology. Most streams originate in the mountains of Hawaii and terminate in the ocean. In general, each of Hawaii 's islands can be divided into two regions, windward and leeward, relative to the prevailing northeasterly trade winds and mountains. On the windward side, orographic rainfall results in high mean annual rainfall sometimes 15 times greater than the mean for Hawaii (25 to 30 inches annually). Consequently, the majority of Hawaii 's perennial streams are located on the windward side of islands. Mean annual rainfall on the leeward side can be in the single digits and intermittent streams that are dry during most of the year are more commonly located in leeward watersheds. Variations in ocean tides, rainfall, soil type, and geology can result in streams having both gaining and losing reaches (Oki, 2003).

Streams in Hawaii also experience extreme flash events characterized by high flows of short duration (stream levels can increase by several feet in less than an hour). These temporal variations in stream flow are due to frequent storms of intense rainfall, small watersheds, steep topography, and limited channel storage. These events can cause massive erosion and deliver tons of sediment to receiving water bodies (Oki, 2003).

What makes this problematic is that nearly most of the area in between is paved surface, not natural open space. That limits the opportunities for ability for the runoff to infiltrate into the soil and be absorbed into the underground water table. This storm water picks up every type of pollutant found on City streets and turns the flood control channels into rainy torrents.

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Q: What is the City and County of Honolulu doing about illegal dumping into storm drains?
A:
Revised Ordinance of Honolulu Section 14.12.23(a) Environmental Quality Control - Violation sates, "It shall be unlawful for any person to discharge or cause to be discharged any pollutant into any drainage facility which causes a pollution problem in state waters, or causes a violation of any provision of the city NPDES permit or the water quality standards of the State of Hawaii." Pollutant means any waste, cooking or fuel oil, waste milk, waste juice, pesticide, paint, solvent, radioactive waste, hazardous substance, sewage, dredged spoils, chemical waste, rock, sand, biocide, toxic substance, construction waste and material and soil sediment. The term also includes commercial FOG waste as defined under Section 14-5A.1.

"Pollution problem" means the discharge of any pollutant into state waters directly or by conveyance through a drainage facility which creates a nuisance or adversely effects the public health, safety, or welfare, or cause s drainage facility to violate any provisions of the city National Pollutant Discharge Elimination System permit or violates any water quality standards of the State of Hawaii. Revised Ordinance of Honolulu Section 14-12.2 Definitions.

Call the City's Environmental Concern Line at 768-3300 to report illegal dumping.

In addition, the Storm Water Program has provided a fact sheet to City employees on how to spot illegal discharge violations and encourages them to report these to the City's Environmental Concern Line.

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Q: I see people dumping used oil into storm drains. What can I do?
A:
Report it to the City's Environmental Concern Line at 768-3300 or the State Clean Water Branch at 586-4309. Dumping used oil is not only illegal but also severely harms the environment. One gallon of oil used can cause an oil slick the size of a football field.
Click here for more information about automobile fluids.
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Q: What happens if I see a neighbor, or know someone who's throwing trash or other pollutants into a storm drain?
A:
If it is someone who you feel is knowingly violating and repeatedly dumping into storm drains, call the City's Environmental Concern Line at 768-3300 or the State Clean Water Branch at 586-4309. If this is an emergency, call 911.

Storm drains are for the sole purpose of handling rain water runoff. Dumping trash, pollutants and debris into the catch basins is illegal. Call the City's Environmental Concern Line to report the illegal dumping. If you know the person, you might explain to them how their actions negatively impact the neighborhood as well as the environment, and that this behavior is highly illegal. Safe, legal alternatives to disposing of waste materials are available throughout the City.

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Q: Detention basin or retention basin, which one is it?
A: The two terms are not interchangeable.

Some terms and phrases used in the business of flood damage reduction seem to come into wide public use, often incorrectly.

DETENTION and RETENTION are two such terms.

Both detention basins and retention basins are devices that can be used to reduce flood damage.

Detention basins temporarily store excess storm water, but have outlets for releasing it. Retention basins do not have outlets and the water is held them until it drains into the soil, evaporates or is pumped out.

Detention Basin Retention Basin

 

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