Find the most up-to-date information about City facility availability, services and programs on the COVID-19 page.

Stormwater Management

Press Enter to show all options, press Tab go to next option

City of Westerville
2014-2018 Stormwater Management Plan 

The City of Westerville maintains the storm water collection system through a series of Best Management Practices. These BMPs are listed as a part of the NPDES Stormwater Management Plan. The storm water collection system consists of the curb inlets, catch basins, manholes, channels, and retention/detention basins that convey the rain water runoff throughout the City of Westerville.

Flood level control is managed by a cooperative effort between the City of Westerville’s Engineering Department and Department of Public Service, The Office of the Franklin County Engineer, the Office of the Delaware County Engineer, the City of Columbus and the United States Corp of Engineers.

The City of Westerville is bounded on the east by the Big Walnut Creek drainage basin and the Alum Creek Drainage Basin is located on the west side.

The Big Walnut Creek drains into Hoover Reservoir well north of the City of Westerville. The waters of Hoover Reservoir are utilized by the City of Columbus to provide source water to the Hap Cramean Water Treatment Plant downstream of the City of Westerville. The waters from the reservoir are controlled by the City of Columbus through Hoover Reservoir Dam. The City of Westerville has a limited amount of drainage area that flows to the Big Walnut Creek drainage area. Downstream of the dam the City of Westerville has a small area of incorporated area.

Alum Creek flows through the western portion of the city. The United States Corp of Engineers has constructed a reservoir on Alum Creek north of the City of Westerville. The City of Columbus pumps water from the Alum Creek Reservoir to the Hoover Reservoir for treatment at the Hap Cramean Water Treatment Plant. The City of Westerville receives most of its source water for the Westerville Water Treatment Plant from Alum Creek just north of Main Street.  This plant is downstream from the Alum Creek Reservoir.   

The United States Corp of Engineers is responsible for flood control from the Alum Creek Reservoir and also must provide waters downstream of the dam for the use of the City of Westerville and to maintain the water levels in the creek.

A large portion of the City of Westerville is tributary to Alum Creek. The City of Westerville is responsible for stormwater quality control as well as flooding control of Alum Creek for the area of the basin contained within the corporate boundaries. There are unincorporated areas around the City of Westerville that contribute waters to Alum Creek. The Delaware County and Franklin County Engineers have responsibility for control of these areas of drainage.

Because of the flood controls in place on the major drainage courses in or near the City of Westerville there is little or no major flooding within the City. Minor flooding along smaller drainage channels may cause damage to open land areas. There has not been flood damage to structures in the City of Westerville in many years.

The City of Westerville’s Engineering Department and the Department of Public Service work in conjunction to maintain and upgrade the stormwater collection system. Through capital improvement projects and proactive maintenance over the last 30 years, the City of Westerville has eliminated virtually every stormwater runoff problem.

Stormwater Collection System Maintenance

The City of Westerville was required to submit a Stormwater Management Plan (SWMP) in accordance with Federal and Ohio Law. The document outlines the City of Westerville’s program to develop, implement and enforce a stormwater management program designed to reduce the discharge of pollutants to the maximum extent practicable, to protect water quality, and to satisfy the appropriate requirements of the Clean Water Act in accordance with the Ohio EPA Phase II program.

The SWMP addresses the six minimum control measures and the Best Management Practices (BMP) that have, or will be, implemented as required by state regulations. The plan also identifies the city’s legal authority to implement the BMPs. The Notice of Intent and SWMP for the original permit were submitted on March 7, 2003.

Legal Authority

The City of Westerville has adopted ordinances that will allow the City the authority to control the quality of separate stormwater discharge to its storm sewer system. This authority will address both industrial and municipal discharges. The City of Westerville has both the fiscal authority and legal resources to fully implement its stormwater management plan.

Through this ordinance, the Department of Public Service of the City of Westerville, develops, monitors, and reports on all BMPs, excluding Construction Site Runoff Control. The Construction Site Runoff Control BMPs are developed, monitored, and reporting performed by the Planning and Development Department of the City of Westerville.

Permit Coverage Area

The stormwater management plan encompasses all areas within the city limits. Westerville has a population of more than 37,000 residents, 170 miles of roadways, 133 miles of Storm Sewer Pipe, and 43 stormwater outfalls discharging to the waters that eventually enter the waters of the state at Alum Creek and Big Walnut Creek.

Reporting Requirements

The City of Westerville will submit its required stormwater report annually. The report includes the status of compliance with the permit conditions, an assessment of the appropriateness of the BMPs and progress towards achieving the measurable goals for each of the six minimum control measures. A summary of the activities the City of Westerville will undertake during the next reporting cycle and any changes to BMPs or measurable goals and all relevant data (monitoring) obtained during the reporting period will be included.

Stormwater Management Plan

This plan outlines the six minimum control measures that will result in significant reductions in pollutants discharged by the City of Westerville. The identified water quality pollutants are fecal coliform, grease, oil and suspended solids. The six minimum controls will address those identified water quality pollutants.

The six minimum controls are:

  1. Public Education/Outreach
  2. Public Participation/Involvement
  3. Illicit Discharge Detection/Elimination
  4. Construction Site Runoff Control
  5. Post Construction Runoff Control
  6. Pollution Prevention/Good Housekeeping.
System Maintenance

Utility Maintenance employees are assigned the task to inspect the public curb inlets, yard drains and piping systems throughout the City of Westerville. Any system defects are assigned to maintenance crews for repairs.

Employees routinely check the city-owned or maintained stormwater basins and open drainage channels for repairs or cleaning.

How You Can Help 

Here are some things that you can do to help prevent stormwater pollution:

  • Pick up litter!
  • Use environmentally friendly materials and follow application instructions carefully for fertilizers, herbicides and pesticides to maximize outcome with the least impact.
  • Never put anything into a stormwater drain other than stormwater.  A single gallon of oil can pollute 100,000 gallons of water.
  • Use rain barrels for irrigation which can help minimize flow downstream and help to minimize your water bill.
  • Use car washes or environmentally friendly cleaners to limit soap from finding reaching our waterways.
  • Do not disturb or mow the area near stream banks.  This will help limit erosion and filter pollutants prior to entering the stream.  
  • Clean up after your pets.  Fecal matter can be very damaging to ecosystems.  
Thank you for doing your part to reduce the impact of stormwater city pollution.  Every little bit counts!

Please direct any questions or concerns to the Department of Public Service, 614.901.6740, Monday - Friday, 7:00 a.m. to 4:00 p.m., or email:


Creek Bank Reclamination    
Creek Bank Reclamination Before Creek Bank Reclamination During Creek Bank Reclamination After
Before During After