The Carrol County regulations (Carrol County Code Chapter 151) are compliant with the National Pollutant Discharge and Elimination System (NPDES) permit requirements for the county’s Municipal Separate Storm Sewer System (MS4). The Department of Land and Resource Management is responsible for the implementation of the NPDES MS4 program in Carrol County. Within the department, the Bureau of Development Review (BDR) reviews all residential, commercial, and industrial plans in the county, and the Bureau of Resource Management (BRM) ensures compliance with permit requirements within the county.
Carrol County encompasses 9 watershed areas, including:
(A) No person shall develop any land for residential, commercial, industrial, or institutional uses without providing for SWM measures that control or manage runoff, from such development except as otherwise provided in this chapter. The SWM measures shall be designed in accordance with this chapter, the Design Manual and the Supplement and constructed in accordance with the approved plan.
(B) This chapter does not apply to development projects with valid final SWM and sediment control approvals prior to May 4, 2010. Where phased developments are approved, each phase is a separate project. Phases where valid individual final SWM and sediment control approvals have not been obtained by May 4, 2010 are subject to the process and requirements of this chapter.
(C) The county may determine that this chapter applies to any development project if downstream flooding problems or danger to health and safety, or damage to property or the environment exist or may be created by runoff from the development.
(2004 Code, § 191-4) (Ord. 01-12, passed 9-27-2001; Ord. 04-07, passed 4-1-2004; Ord. 2010-05, passed 4-29-2010)
(A) SWM plans for redevelopment shall provide ESD to the MEP consistent with the Design Manual and the Supplement. Overbank flood protection volume requirements do not apply unless required by the county in uncommon situations such as historic flooding, or extreme erosion where more stormwater control than the minimum required may be necessary.
(C) All redevelopment project designs shall reduce those existing site impervious areas within the limit of disturbance (LOD) built in accordance with an approved site plan by at least 50% below conditions existing on the date of the most recent county geographic information system orthophotography or as depicted on the original approved site plan. Where site conditions prevent the reduction of impervious area, then SWM practices shall implement ESD to the MEP for at least 50% of the site’s impervious area. When a combination of impervious area reduction and ESD is used, the combined reduced and treated area shall equal no less than 50% of the site’s impervious area within the LOD. Where existing site impervious areas were constructed after July 1, 1984, without an approved SWM plan, SWM shall be provided in accordance with § 151.035 for all impervious surfaces on the parcel.
(D) Alternative SWM measures may be used to meet the requirements in division (B) above if the owner or developer satisfactorily demonstrates to the county that impervious area reduction has been maximized and ESD has been implemented to the MEP. Alternative stormwater management measures include but are not limited to:
(1) An on site structural BMP;
(2) An off site structural BMP to provide water quality treatment for an impervious area equal to or greater than 70% of the existing impervious area;
(3) A combination of impervious area reduction, ESD implementation, and an on site structural BMP for an area equal to or greater than 50% of the existing site impervious area within the LOD; or
(4) A combination of impervious area reduction, ESD implementation and an off site structural BMP for an area equal to or greater than 70% of the existing site impervious area within the LOD.
(E) The county policies for providing stormwater runoff treatment for redevelopment projects if it is proven to the county’s satisfaction that the requirements of divisions (A), (B), and (C) above cannot be met are as follows:
(1) Retrofitting of existing on site or off site BMPs that provide inadequate stormwater treatment for the impervious areas draining to them, identified by the county within the eight digit drainage basin of the project, to bring them up to current standards in accordance with the Design Manual and the Supplement. The retrofitted facilities must treat drainage from impervious areas that require additional treatment greater than that required for all site imperviousness within the LOD; or
(2) Fees paid into the Stormwater Management Fund established in § 151.067 for the exclusive purpose of providing management of stormwater . The fees shall be listed in the Supplement and updated annually based upon cost history and the square footage of site imperviousness within the LOD.
(2004 Code, § 191-8) (Ord. 01-12, passed 9-27-2001; Ord. 04-07, passed 4-1-2004; Ord. 2010-05, passed 4-29-2010,passed 11-29-2018)
(A) The design of SWM plans shall be prepared by a professional land surveyor or engineer.
(B) If a stormwater BMP requires a dam safety permit or small pond approval, the design shall be prepared by a professional engineer.
(2004 Code, § 191-15) (Ord. 01-12, passed 9-27-2001; Ord. 04-07, passed 4-1-2004)
(A) There is hereby established a Stormwater Management Fund (“the Fund”) to be administered by the Department of the Comptroller, or its successor agency.
(B) All penalties, fines, and retrofit, variance, or other fees paid pursuant to this chapter shall be deposited to the SWM Fund. Interest shall be deposited to the Fund. All money deposited to the Fund shall be used for program management and compliance with this chapter.
(2004 Code, § 191-17.1) (Ord. 01-12, passed 9-27-2001; Ord. 04-07, passed 4-1-2004; Ord. 2010-05, passed 4-29-2010)
Any grading or building permit issued by the county may be suspended or revoked after written notice is given to the permittee for any of the following reasons:
(A) Any violation of the conditions of the SWM plan approval;
(B) Changes in site runoff characteristics upon which an approval or waiver was granted;
(C) Construction not in accordance with the approved plan;
(D) Noncompliance with a correction notice or stop work order issued for the construction of the SWM ESD nonstructural or structural practices; or
(E) Immediate danger exists in a downstream area as determined by the county.
(2004 Code, § 191-18) (Ord. 01-12, passed 9-27-2001; Ord. 04-07, passed 4-1-2004; Ord. 2010-05, passed 4-29-2010)
(A) The county shall ensure that preventative maintenance is performed by inspecting all ESD, non-structural treatment systems and structural stormwater treatment measures. Inspection shall occur during the first year of operation and at least once every three years thereafter. In addition, a Stormwater Management Deed of Easement and Maintenance Agreement between the owner and the county shall be executed for ESD, non-structural treatment systems and structural stormwater treatment measures as required by this chapter.
(B) Inspection reports shall be maintained by the county for ESD, non-structural treatment systems and structural stormwater treatment measures.
(C) Inspection reports for ESD, non-structural treatment systems and structural stormwater treatment measures shall include the following:
(D) After notification of any deficiencies discovered from an inspection of a structural SWM facility, the owner shall have 30 days or other time frame as determined by the county to correct the deficiencies. The county shall conduct a subsequent inspection to ensure completion of the repairs.
(E) If repairs are not properly completed, the county may initiate enforcement proceedings.
(F) If, after an inspection by the county, the condition of a structural SWM facility presents an immediate danger to the public health or safety, the county may take action as may be necessary to protect the public and make the facility safe. Any cost incurred by the county shall be assessed against the owner pursuant to this chapter.
(2004 Code, § 191-23) (Ord. 01-12, passed 9-27-2001; Ord. 04-07, passed 4-1-2004; Ord. 2010-05, passed 4-29-2010, passed 11-29-2018)
(2004 Code, § 191-24) (Ord. 01-12, passed 9-27-2001; Ord. 04-07, passed 4-1-2004; Ord. 2010-05, passed 4-29-2010, passed 11-29-2018)
Carroll County Stormwater Design Manual Volumes I & II
Stormwater Review Fee Computation Sheet
Maryland Stormwater Design Manual