1474                             Laws of Maryland                      [Ch. 521

The contributory drainage area for an impoundment constructed
across a waterway shall not be in excess of four hundred (400)
acres in any portion of the State northerly and westerly from the
main line tracks of the Baltimore and Ohio Railroad Company be-
tween the District of Columbia and the State of Delaware (en route
to Wilmington, Delaware); and the contributory drainage area shall
not be in excess of seven hundred (700) acres in any portion of the
State southerly and easterly from such main line tracks. However,
impoundments created by diverting water from an existing water-
course to an off-site storage or bypass pond may be constructed
without regard to the watershed area of the stream from which
water is diverted, except that the directly contributing watershed
area shall not be in excess of one hundred (100) acres.

If a grass covered spillway is used, the maximum velocity of the
flow of water over the spillway shall not be in excess of an amount
that will produce scouring, as determined in each instance by the
State Soil Conservation Committee. A spillway shall not be con-
structed on an artificial embankment or made-fill, but shall be cut
only from natural and undisturbed earth, seeded or sodded and com-
pacted by rolling.

The freeboard of the dam or embankment, measured upward from
the water elevation in the reservoir under design storm conditions,
shall be at least equal to frost depth plus one foot, or to wave height
plus one foot, whichever is the greater, except that in no event shall
it be less than thirty (30) inches.

Any limitation on contributing watershed area, depth of water,
and water surface area shall not be construed to apply to impound-
ments created entirely by excavation below the existing ground level,
these being known generally as dugout ponds. Also, ponds which
exceed any of the limitations described in this subsection may be
constructed in locations where there are no downstream hazards, if
approved in each instance by the Department.

The plans and specifications for any proposed pond or embankment
shall be submitted in advance to the Department for review, to
ascertain that they conform to the provisions and requirements of
this subsection. All construction work shall be under the continued
supervisory authority of the State Soil Conservation Committee or of
other persons satisfactory to the Department, to assure that it con-
forms to the provisions and requirements of this subsection.]

(C)    THE DEPARTMENT, BY REGULATION, MAY DESIG-
NATE INTERJURISDICTIONAL WATERSHEDS IN WHICH
ALL IMPOUNDMENT PROPOSALS SHALL BE SUBJECT TO
REVIEW AND APPROVAL BY THE DEPARTMENT FOR
STANDARDS RELATING TO SAFETY AND FLOOD CONTROL.
GWYNNS FALLS, JONES FALLS AND HERRING RUN, SIT-
UATED IN OR ADJACENT TO BALTIMORE CITY, ARE SO
DESIGNATED.

(D)    NOTHING WITHIN THIS SUBTITLE SHALL BE
DEEMED A RESTRICTION OR LIMITATION UPON THE DE-
PARTMENT OF NATURAL RESOURCES JURISDICTION OVER
WASTE TREATMENT STRUCTURES, INCLUDING BUT NOT
LIMITED TO DAMS, IMPOUNDMENTS, PONDS AND LA-