Submission and approval of a stormwater management plan will
comply with a comprehensive stormwater management plan review and
approval process administered by the Department that:
A. Considers all aspects of project planning, design, and construction
from initial conception through final approval;
B. Requires the submission, review, and approval of interim plans at
an increasing level of detail for specific stages of project development;
and
C. Provides for coordinated input for all plans from all appropriate
agencies, departments or divisions, including, but not limited to,
Planning, Zoning, Public Facilities and the District.
The stormwater management plan and all supporting documents
shall be signed and sealed by a professional engineer or other licensed
professional as allowed under Maryland law. If the BMP requires either
a dam safety permit or small pond approval, then the design shall
be prepared by a professional engineer.
The following additional information may be required at any
stage (concept, site and/or final) of the stormwater management plan
reviews:
A. Site characteristics:
(1) Intended use of the structures, including design criteria, trade-off
conditions and/or areas not managed (NRCS Engineering Field Manual,
Chapter II).
(2) Structure classification (NRCS Pond Standard Code 378).
(3) Soils investigations for construction of small ponds, infiltration
facilities and any other stormwater management system per the Design
Manual for review by the District and the Department.
(4) Topographic survey, including the area necessary to determine the
downstream effect from any proposed stormwater management structure.
(5) Topographical information of the contributing watershed based upon
United States Geological Survey (USGS) topographic quadrangles with
a field-verified drainage area and acreage noted on the plan or County
topographic maps at one inch equals 200 feet.
(6) Geotechnical investigations, including soils maps, borings, site-specific
recommendations, and any additional information necessary for the
proposed stormwater management plan design.
(7) Descriptions of all watercourses, impoundments, and wetlands on or
adjacent to the site or into which stormwater directly flows.
B. Computations:
(4) Unified sizing criteria volume computations according to the Drainage
Manual;
(5) For development proposed in the IDZ within the County critical area,
the predevelopment and post-development pollutant loadings; and
(6) Any other information as required by the County Engineer in a format
as approved by the Department.
C. Grading and sediment control plan (Charles County Grading and Sediment
Control Ordinance and Standards and Specifications for Soil Erosion and
Sediment Control in Developing Areas):
D. Construction cost estimate.
F. If the plans include precast structures, then the developer shall
be responsible to submit shop drawings (approved by the design engineer)
to the County prior to the placement of the precast structure. The
information required on the shop drawing is as outlined in the Plan
Preparation Package.
G. Adequate outfall study. The developer's study of the downstream
conditions shall extend to the point where an adequate outfall exists
as determined by calculations or to the point as determined by the
design engineer and as approved by the County Engineer.
H. Standards and specifications. Stormwater management plans must be
prepared in sufficient detail, with reference to appropriate standards
and specifications, to ensure understanding by those responsible for
review, installation, and inspection.
I. The developer will certify on the drawings that all clearing, grading,
construction and development will be accomplished strictly in accordance
with the final stormwater management plan. Changes made during the
construction process will not be permitted without prior written approval
of the Department and, where a small pond is involved, the District.
The licensed professional will certify on the drawings that the plan
meets all applicable, County, state and federal laws.
J. In the case of a small pond, the developer shall retain a licensed
professional to inspect the construction of the pond. The licensed
professional shall submit routine inspection reports with test results
at time intervals established by the County Engineer. The licensed
professional shall not accept any work not in compliance with state
or County requirements and shall notify the County immediately when
work is not in compliance.
K. The design plans will indicate the one-hundred-year floodplains,
backwaters, ponding for streams, culverts, storm drain systems, and
the maximum impounded water surface elevation of the stormwater management
structure during ultimate emergency spillway operation. The resultant
inundated area at this elevation shall be accurately delineated and
recorded on the site plan or plat as a perpetual stormwater management,
floodplain, backwater, or drainage easement, as applicable. Additional
buffer easements may be necessary or required for maintenance, access,
and/or safety purposes. No existing or proposed building structures
will be allowed within these easements without prior approval of the
Department. Peripheral construction may be granted, provided that
all floor elevations are at least one foot higher than the maximum
water surface elevation.
The Department will require stormwater management systems to
be protected by public or private easements or private inspection
and maintenance agreements. All inspection and maintenance agreements,
easement documents, and record plats shall be recorded prior to permit
issuance.
Unless approved otherwise by the County Engineer, stormwater
management for private residential, private commercial, private industrial
or institutional developments shall be located outside of County-owned
rights-of-way, properties and public easements.
A. Residential subdivisions. Structural stormwater management located
in residential developments shall be located outside residential lots
and shall be maintained by a homeowners' association. Nonstructural
stormwater management designed to address the stormwater management
requirements may be located on the lot if the stormwater management
measure is to address the lot development and not the infrastructure
development.
B. Nonresidential development. Stormwater management measures located
in nonresidential areas such as commercial, industrial and institutional
development shall be located on the developer's property or an
approved off-site property and shall be maintained by the owner of
the property.
C. Public development and maintenance. The County will maintain any
stormwater management system located in public rights-of-way or within
public easements dedicated to and accepted by the County.
Stormwater management and development plans shall be consistent
with adopted and approved watershed management plans or flood management
plans as approved by the Department in accordance with the Flood Hazard
Management Act of 1976 (Environment Article, Title 5, Subtitle 8,
Annotated Code of Maryland).
An operation and maintenance plan for all stormwater management
systems shall be required as a condition of final stormwater management
plan approval and shall be included on the stormwater management plan
sheets. A copy of the operation and maintenance plan shall be provided
to the parties responsible for the maintenance of the stormwater management
system.
If a project involves the discharge of some or all of the stormwater
runoff from the site in a manner that alters the water quality or
the flow characteristics of depth, velocity, width, rate, or volume
from that which exists in the pre-developed condition, the developer,
prior to the issuance of a permit, shall obtain from abutting property
owner(s) any necessary easement, right-to-discharge, or other property
interest concerning flow of water. Approval of a stormwater management
plan does not create or affect any right to direct runoff onto adjacent
property without that property owner's permission.