Stormwater Management

Stormwater Management (SWM) reviews grading and stormwater management plans for proposed construction activities and requires inspection and maintenance of public and privately-owned stormwater management facilities.

STORMWATER ENGINEERING REGULATIONS

Runoff from impervious surfaces affects local streams by increasing erosion along stream banks, silting in stream beds and depositing trash in waterways. The cumulative effect is a reduction in water quality, aquatic resources and the health of streams and the Chesapeake Bay. To improve the effects of stormwater runoff, and thereby improve the quality of the Chesapeake Bay, the Maryland legislature passed the Storm Water Management (SWM) Act of 2007. Baltimore County has revised its Code to incorporate these State-mandated changes. This is under County Code Article 33, Title 4.

This Act significantly affects the design of stormwater components for land development projects. Some of the more significant changes are:

  • Environmental Site Design (ESD) to the Maximum Extent Practicable (MEP) must be addressed for all projects, including redevelopment.
  • Three sequential plan submissions and reviews are now required: Concept SWM Plan; Development SWM Plan; and Final SWM Plan.
  • Redevelopment projects require 50 percent reduction in impervious surface or equivalent water quality management.
  • No grading or building permits may be issued until sediment control and SWM plans are signed.

To review the COMAR revisions and become familiar with all the changes to the Design Manual, visit the Maryland Department of the Environment website.

GRADING AND STORMWATER PLAN REVIEW

Use the checklists and forms below when preparing plans for review by Stormwater Engineering.

  • Grading and Sediment Control Review Procedures
    This document details the procedures for grading submittals to the various Baltimore County agencies responsible for plan approval.
  • TR-55 Design Computation
    Baltimore County’s spreadsheet for TR-55 design and typical to the industry.
  • SWM and Grading Plans Stamps
    Shows the various approval stamps to be placed on Grading and Stormwater Plans. Sentences in red are for location information and not to be placed on plan.
  • SWM Certifications and As-Built Note
    Shows the various certifications to be placed on Stormwater Management Plans. Sentences in red are for location information and not to be placed on plan.
  • Summary Tables for Structural BMPs
    Shows required design summary and pond specifications for MD-378 ponds.
  • Operation and Maintenance Schedules
    Shows the operation and maintenance schedules for privately owned and maintained ESD practices.
  • SWM Data Sheet
    Engineers complete and provide data for the project SWM facility, BMP or ESD credit. This information is required for complete and accurate reporting to Maryland Department of the Environment (MDE). Use the following information sheets to assist in completing the Facility Data Sheet.
  • As-Built Submittal Requirements
    Construction inspection and item requirements for engineer's as-built submission to Baltimore County's Stormwater Engineering Section.

SWM FACILITY INSPECTION AND MAINTENANCE

Stormwater management facilities collect the stormwater runoff from all of the drainage area for the communities that they service. Their primary function is to provide water quantity and quality management to lessen the impact of runoff that enters the downstream stream system during and immediately after a storm event. County facilities are allowed to naturalize in order to provide enhanced water quality for the first inch of rainfall—the rainfall that is most likely to be carrying pollutants washed from the impervious surfaces within the community.

INSPECTIONS

The Department of Environmental Protection and Sustainability (DEPS) staff and contractors inspect all publicly and privately-owned SWM facilities in Baltimore County. Facilities are first inspected by the County following the submission and approval of as-built plans. The next inspection occurs following a one-year maintenance period to ensure the facility is functioning as designed. After passing the one-year inspection, the facilities are reinspected every three years.  

Inspectors use the Inspection Report Sheet in the field for SWM and Water Quality facilities to determine compliance with Baltimore County stormwater management regulations. 

MAINTENANCE

Unlike inspections, property owners are responsible for the maintenance of a SWM facility. Following each inspection, the property owner receives written confirmation the facility passed inspection, or a written list of repair and maintenance items. The property owner is then responsible for repairing the facility at their own expense.  

For questions regarding maintenance of a publicly-owned SWM facility, contact Scott Porter, SWM Operations Supervisor at 410-887-3768 or sporter@baltimorecountymd.gov.