Cecil County, MD
 
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Table of Contents
Table of Contents
A. 
The minimum control requirements established in this section and the Design Manual are as follows:
(1) 
The Department of Public Works shall require that the planning techniques, nonstructural practices, and design methods specified in the Design Manual be used to implement ESD to the MEP. The use of ESD planning techniques and treatment practices must be exhausted before any structural BMP is implemented. Stormwater management plans for development projects subject to this chapter shall be designed using ESD sizing criteria, recharge volume, water quality volume, and channel protection storage volume criteria according to the Design Manual. The MEP standard is met when channel stability is maintained, predevelopment groundwater recharge is replicated, nonpoint source pollution is minimized, and structural stormwater management practices are used only if determined to be absolutely necessary.
(2) 
In the coastal plain, the following minimum control requirements apply in accordance with the Design Manual and must be addressed utilizing ESD to the MEP:
(a) 
Water quality volume;
(b) 
Recharge volume;
(c) 
Channel protection storage volume; and
(d) 
Overbank flood protection volume for the two-year-frequency storm event may be required if the Department determines downstream conditions so warrant. (Structural practices may be considered only if ESD measures implemented to the MEP cannot provide the necessary volume.).
(3) 
In the Piedmont Region, the following minimum control requirements apply in accordance with the Design Manual and must be addressed utilizing ESD to the MEP:
(a) 
Water quality volume;
(b) 
Recharge volume;
(c) 
Channel protection storage volume; and
(d) 
Overbank flood protection volume for the ten-year-frequency storm event may be required if the Department determines downstream conditions so warrant (Structural practices may be considered only if ESD measures implemented to the MEP cannot provide the necessary volume.).
(4) 
Except as provided below, in the Transition Region the minimum control requirements shall be those as specified for the Piedmont Region. If an applicant demonstrates that the site to be developed within the Transition Region contains predominantly coastal plain characteristics for topography and soils, then the minimum control requirements shall be that of the coastal plain. To be considered predominantly coastal plain topography, the average slope on the site to be developed, from the highest elevation to the lowest elevation, must be 8% or lower. To be considered predominantly coastal plain soils, at the concept plan phase a soils report indicating that the site to be developed contains greater than 50% of soils determined by the Engineer to be classified as coastal plain. At the preliminary plan phase, the soils report must be certified and sealed by a Maryland-registered geotechnical engineer [See § 325-14(A)(6) for the minimum information required in a soils report.] for any proposed structural practices.
(5) 
In addition to the applicable requirements above, all development and redevelopment activities that take place in the intensely developed areas (IDA) of the Chesapeake Bay Critical Area shall result in a reduction of pollutant loadings from the site by at least 10%. The process for determination of pollutant loading reduction shall be as outlined by the Critical Areas Commission in "A Framework for Evaluation of Compliance with the 10% Rule in the Critical Area," April 1987, or a comparable methodology as approved by the Department of Public Works.
(6) 
The Department of Public Works may require more than the minimum control requirements for overbank flood protection for the two- and ten-year-frequency storm event if hydrologic or topographic conditions warrant or if flooding, stream channel erosion, or water quality problems exist downstream from the proposed project.
B. 
Stormwater management and development plans, where applicable, shall be consistent with adopted and approved watershed management plans or flood management plans as approved by the Maryland Department of the Environment in accordance with the Flood Hazard Management Act of 1976.[1]
[1]
Editor's Note: See Environment Article, Title 5, Subtitle 8, § 5-801 et seq., Annotated Code of Maryland.
The ESD planning techniques and practices and structural stormwater management measures established in this chapter and Design Manual shall be used, either alone or in combination, in a stormwater management plan. A developer shall demonstrate that ESD has been implemented to the MEP before the use of a structural BMP is considered in developing the stormwater management plan.
A. 
ESD planning techniques and practices.
(1) 
The following planning techniques shall be applied according to the Design Manual to satisfy the applicable minimum control requirements established in § 325-10 of this chapter:
(a) 
Preserving and protecting natural resources;
(b) 
Conserving natural drainage patterns;
(c) 
Minimizing impervious area;
(d) 
Reducing runoff volume;
(e) 
Using ESD practices to maintain 100% of the annual predevelopment groundwater recharge volume;
(f) 
Using green roofs, permeable pavement, reinforced turf, or other alternative surfaces;
(g) 
Limiting soil disturbance, mass grading, compaction and placing four inches of topsoil on any area(s) which has been disturbed;
(h) 
Clustering development; and
(i) 
Any practices approved by the Administration.
(2) 
The following ESD treatment practices shall be designed according to the Design Manual to satisfy the applicable minimum control requirements established in § 325-10 of this chapter:
(a) 
Disconnection of rooftop runoff;
(b) 
Disconnection of non-rooftop runoff;
(c) 
Sheet flow to conservation areas;
(d) 
Rainwater harvesting;
(e) 
Submerged gravel wetlands;
(f) 
Landscape infiltration;
(g) 
Infiltration berms;
(h) 
Dry wells;
(i) 
Micro-bioretention;
(j) 
Rain gardens;
(k) 
Swales;
(l) 
Enhanced filters; and
(m) 
Any practices approved by the Administration.
(3) 
The use of ESD planning techniques and treatment practices specified in this section shall not conflict with existing state law or local ordinances, regulations, or policies. Counties and municipalities shall modify planning and zoning ordinances and public works codes to eliminate any impediments to implementing ESD to the MEP according to the Design Manual. In the event that there is a conflict between local ordinances and the Cecil County Stormwater Management Ordinance, the Stormwater Management Ordinance shall take precedence.
B. 
Structural stormwater management measures.
(1) 
The following structural stormwater management practices shall be designed according to the Design Manual to satisfy the applicable minimum control requirements established in § 325-10 of this chapter:
(a) 
Stormwater management ponds;
(b) 
Stormwater management wetlands;
(c) 
Stormwater management infiltration;
(d) 
Stormwater management filtering systems; and
(e) 
Stormwater management open channel systems.
(2) 
The performance criteria specified in the Design Manual with regard to general feasibility, conveyance, pretreatment, treatment and geometry, environment and landscaping, and maintenance shall be considered when selecting structural stormwater management practices.
(3) 
Structural stormwater management practices shall be selected to accommodate the unique hydrologic or geologic regions of the state.
C. 
ESD planning techniques and treatment practices and structural stormwater management measures used to satisfy the minimum requirements in § 325-10 of this chapter must be contained within an easement recorded in the land records of Cecil County and remain unaltered by subsequent property owners. Whenever feasible, ESD planning techniques and treatment practices and structural stormwater management measures must be contained within common open space areas. Placing stormwater management measures within areas which will become County right-of-way should be avoided. Prior approval from the Department of Public Works shall be obtained before any stormwater management practice is altered.
D. 
Alternative ESD planning techniques and treatment practices and structural stormwater measures may be used for new development runoff control if they meet the performance criteria established in the Design Manual and all subsequent revisions and are approved by the Administration. Practices used for redevelopment projects shall be approved by the Department of Public Works.
E. 
For the purposes of modifying the minimum control requirements or design criteria, the owner/developer shall submit to the Department of Public Works an analysis of the impacts of stormwater flows downstream in the watershed. The analysis shall include hydrologic and hydraulic calculations necessary to determine the impact of hydrograph timing modifications of the proposed development upon a dam, highway, structure, or natural point of restricted stream flow. The point of investigation is to be established with the concurrence of the Department of Public Works, downstream of the first downstream tributary whose drainage area equals or exceeds the contributing area to the project or stormwater management facility.
The basic design criteria, methodologies, and construction specifications, subject to the approval of the Department of Public Works and the Administration, shall be those of the Design Manual.