Definition of Stormwater
Stormwater is the discharge of water due to runoff from precipitation. Stormwater runoff occurs
when precipitation from rain or snowmelt flows over impervious surfaces. Impervious surfaces are areas that impede the infiltration of water into the soil. Concrete,
asphalt, rooftops and even severely compacted areas of soil are
Stormwater can pick up debris, chemicals, dirt and other pollutants. These substances are then carried directly to a waterway or into a storm drain/inlet. Storm drains are connected to a series of underground pipes that lead to waterways (stream or river). Stormwater systems are not designed to capture debris or treat the water as in a sanitary sewer system that leads to a wastewater treatment plant. They carry stormwater directly, without treatment, to local waterways. This discharge can destroy aquatic habitat, lessen aesthetic value and threaten public
health (with contaminated food, drinking water supplies, and recreational
waterways). For more information on preventing waterways pollution go to Project Clean Rivers.
The following are guidelines for preventing stormwater pollution:
- Compost or mulch yard waste. Don't leave it in the street or sweep into storm drains or streams.
- Use lawn care products (ie: fertilizer, herbicides, and pesticides) sparingly.
- Plant trees and vegetation. The root system stabilized the ground and thus slowing runoff and erosion.
- Properly dispose of
household hazardous waste (ie: engine oils, paints, pesticides, etc),
yard waste, pet waste, and kitchen grease.
- Never dump anything into storm drains and sewers (it is illegal).
- Keep drainage ditch and swales free of debris, litter, and obstructions.
- Wash cars at a commercial wash or over areas of gravel or grass.
- Sweep debris from sidewalks and driveways rather than washing debris away.
- Report hazardous spills, illegal dumping, blockages, and unusual odors.
Gahanna Woods Detention Basin
The Gahanna Woods Detention Basin is located off of Taylor Station Rd just south of Havens Corners Rd. The basin is part of the Gahanna Woods Park and is adjacent to the Gahanna Woods Nature Preserve. It was built in 2012 to detain peak stormwater flows and improve water quality in the stream. Click here for more details.
Sycamore Run Stream Restoration
Upstream development has caused high water flows along the lower reaches of the Sycamore Run Watershed during storm events. This in turn has resulted in severe stream erosion, floodplain degradation and increased pollutant loads along the stretch of stream adjacent to the Sycamore Woods Condominiums. In addition, the increase of water flow during such events enables the stream channel to erode to a deeper channel. This prevents water from extending into the floodplain where water can be stored and sediment and pollution can be trapped.
The City has secured a federal grant through the Section 319(h) Nonpoint Source Program to fund a stream restoration project. The project consists of restoring over 1,000 feet of the Sycamore Run by stabilizing the stream channel, reconnecting the wooded floodplain to the stream, developing floodplain wetlands, installing grade control structures and planting native riparian vegetation to reinstate natural stream habitat. The water quality downstream of the project will be improved through biological processes within the stream and the trapping of sediments in the new floodplain. The increased floodplain area will also help reduce flow velocity of the stream during rain events. This will allow natural stream bank vegetation to thrive, thus stabilizing the banks from erosion while providing habitat for native wildlife. After the project is complete, the area will be accessible to the public and will include a trail and interpretive signs. Click here for more details.
Rain Barrels and Rain Gardens
When it rains, water from impervious surfaces (roof, driveway, parking lot, road, etc) is directed to storm drain inlets. Before this runoff reaches the storm drain, it picks up pesticides, excess nutrients from fertilizers, litter, pet waste, fluids from leaking cars and other pollutants as it moves over the land. Once the runoff enters the storm sewer system it travels, unfiltered and untreated, directly to the nearest stream. This pollutant load is harmful to the aquatic environment and degrades the stream’s water quality. In addition, the sudden surge and velocity of runoff during a storm event causes stream erosion, floodplain degradation and sometimes flooding.
Stream degradation due to stormwater runoff is a problem affecting streams all across Franklin County. Stormwater is entering local streams in ever increasing amounts. Streams that were once trickles are now torrents during rain events. Rain barrels and rain gardens are two measures that you can take at home to combat stormwater and protect our waterways.
A rain barrel is a drum barrel that is used as a cistern to collect and store rainwater from your roof. Rainwater that would otherwise be lost as runoff can then be used to water your lawn/flowers, wash your car, top off a swimming pool and other such activities. One advantage of rain barrels is that they save homeowners money while protecting waterways. If a homeowner waters for only one hour each week with a 1/2-inch garden hose, the savings from using a rain barrel can amount to nearly $90 over the growing season! Gahanna is a participant in Franklin Soil and Water Conservation District’s GreenSpot Backyards Conservation Program. The low-cost rain barrel that is available to Gahanna homeowners through the program is an attractive, terracotta colored barrel with a lid that can be reversed to hold summer flowers. The barrel has a diverter that installs easily in a downspout and eliminates overflow problems.
A rain garden is a shallow depression located near a source of runoff that is planted with deep-rooted native vegetation. Native plants slow the flow of stormwater from impervious surfaces and allow the runoff to slowly infiltrate the ground. Rain gardens are designed to withstand high concentrations of nutrients, specifically nitrogen and phosphorous, that are common in stromwater runoff. Prime locations for rain gardens are near downspouts, driveways, sump pump outlets or in the path of stormwater flow through a yard. The Central Ohio Rain Garden Initiative (CORGI) is a cost share program that offers homeowners up to $250 to install a rain garden on their property (number of grants available each year are limited).
Both alternative approaches to stormwater management help to eliminate pollution distribution into the stream, control erosion, prevent flooding and improve water quality. If you would like further information about rain barrels or rain gardens or to register for one, call Franklin Soil and Water Conservation District at 614-486-9613 or visit www.franklinswcd.org. Click here for the 2015 informational flyer.
NPDES Phase II Program
The City owns and maintains a system of storm drains and pipes that are designed to carry stormwater (rain and snowmelt) from areas of potential flooding (ie: streets and parking lots) to the closest stream. This system, which also includes roadside ditches, is known as a municipal separate storm sewer system or MS4 for short. Unlike sanitary sewer systems, MS4s do not lead to a wastewater treatment plant. They carry stormwater directly, without treatment, to local waterways.
The U.S. Environmental Protection Agency and the Ohio Environmental Protection Agency enforce urban stormwater regulations. These regulations are associated with a program known as the National Pollutant Discharge Elimination System (NPDES). This program requires local governments to develop a plan to reduce stormwater pollution in order to protect and improve waterways.
The program is comprised of six control measures that will reduce pollutant discharge. These include the following:
- Public Education and Outreach: newsletters, websites, and workshops relating stormwater issues
- Public Participation and Involvement: programs and events that involve people in stormwater management (ie: the rain garden initiative and stream cleanup days)
- Illicit Discharge Detection and Elimination: ensures that only rainwater and snowmelt go down the drain
- Construction Site Runoff Control: review construction project's site plans to certify sediment, excessive runoff, and pollution will not enter streams or waterways
- Post-Construction Runoff Control: verify that runoff and pollution control structures are maintained
- Pollution Prevention and Good Housekeeping: measures taken by the City to protect waterways (ie: street sweeping and catch basin maintenance)
The City is required to submit a NPDES report for their MS4 system every year to the Ohio EPA in order to receive a permit to allow stormwater to enter streams and rivers. Click here to review the Gahanna's 2013 NPDES report.
Illicit Discharge Detection and Elimination (IDDE) PLan
The Illicit Discharge Detection and Elimination (IDDE) Plan is a component of the National Pollutant Discharge Elimination System (NPDES) program described above. This plan outlines how the City will find and eliminate pollutants that are entering the MS4 illegally to ensure that only rainwater and snowmelt go down the storm drain. Pollutants are categorized as anything other than clean rainwater or snowmelt. These ‘illicit discharges’ can enter through a storm drain on a street or parking lot, a pipe from a poorly functioning household sewage treatment system or a home or workplace drain connected to the MS4 instead of the sanitary sewer system.
The primary method that Gahanna uses to monitor pollutants entering its MS4 is dry-weather screening. Inspectors check outfalls, where storm sewer pipes empty to local waterways. If there has been no rain for a few days, and water is flowing from the pipes, where is it coming from? If it is clean, it may be from groundwater infiltration or a small stream that was enclosed in a pipe during development. Unfortunately, it is often from a poorly functioning septic system and is contributing nutrients, detergents and E. coli to a local stream. Other instances of illicit discharge might be washing machines incorrectly draining into basement sumps, car repair or other small business floor drains connected to storm sewer lines and homeowners dumping paint, automotive fluids, dead leaves, pet waste, etc down curbside storm drains.
Another important aspect of the City's IDDE plan is encouraging residents to report when they see or smell signs of pollutants in local streams or ditches. If you see or smell signs of pollutants please contact the Department of Public Service at 614-342-4005 between 8:00 am and 5:00 pm, Monday through Friday.
For more information and an opportunity to review the IDDE Plan, click here. The City welcomes public comments on the plan. If you are interested in submitting comments, click here.
Stormwater management plan
The City is required to submit a stormwater management plan to the Ohio EPA during the first term of the permit cycle. The report outlines the City's compliance status with permit regulations (such as NPDES), an evaluation of management procedures and analysis of progress goals. The Stormwater Management Plan can be found by clicking here.
Ohio Department of Natural Resources, ODNR:
Franklin Soil and Water Conservation District, FSWCD:
Ohio Environmental Protection Agency, OhioEPA: