The ESD planning techniques and practices and structural stormwater
management measures established in this chapter and the Design Manual
shall be used, either alone or in combination with a stormwater management
plan. The applicant 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 §
14:4-14 of this chapter:
(a)
Preserving and protecting natural resources;
(b)
Conserving natural drainage patterns;
(c)
Minimizing impervious area;
(e)
Using ESD practices to maintain 100% of the annual predevelopment
groundwater recharge volume;
(f)
Using permeable pavement, reinforced turf, and other alternative
surfaces;
(g)
Limiting soil disturbance, mass grading, and compaction;
(h)
Clustering development; and
(i)
Other practices approved by the Administration.
(2) The following ESD treatment practices shall be evaluated according to the Design Manual to satisfy the applicable minimum control requirements established in §
14:4-14 of this chapter:
(a)
Disconnection of rooftop runoff;
(b)
Disconnection of non-rooftop runoff;
(c)
Sheet flow to conservation areas;
(g)
Submerged gravel wetlands;
(o)
Any practices approved by the Administration.
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 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 character of the site.
C. ESD planning techniques and treatment practices and structural stormwater
management measures used to satisfy minimum control requirements of
this chapter must be recorded in the land records of Queen Anne's
County and remain unaltered by subsequent property owners. Prior approval
from the Department shall be obtained before any stormwater management
practice is altered.
D. Alternative ESD 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.
E. For the purposes of modifying the minimum control requirements or
design criteria, the applicant shall submit to the Department 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 shall be established
with the concurrence of the Department.