504                             LAWS OF MARYLAND                      [CH. 240

fire-fighting apparatus, recreation, health, light and air, and for the
avoidance of congestion of population, including minimum width and
area of lots.] In exercising the powers referred to in Section 230 the
Howard County Planning Commission shall prepare regulations and
amendments thereto, governing the subdivision of land and building
development within its jurisdiction. Such regulations and amend-
ments may provide for (1) the harmonious development of the
county; (2) the coordination of roads within the subdivision with
other existing, planned, or platted roads or with other features of
the county or with the Commission's master plan or with any road
plan adopted or approved by the Commission as part of the Com-
mission's master plan; (3) adequate open spaces for traffic, recrea-
tion, light, and air, by dedication or otherwise, and the dedication to
public use or conveyance of areas designated for such dedication
under the provisions of zoning regulations relating to average lot
size, cluster subdivision or planned community development; (4) the
conservation of or production of adequate transportation, water,
drainage, and sanitary facilities; (5) the preservation of the loca-
tion of and the volume and flow of water in and other characteristics
of natural streams and other waterways; (6) the avoidance of popu-
lation congestion; (7) conformity of resubdivided lots to the charac-
ter of lots within the existing subdivision with respect to area, front-
age, and alignment to existing lots and streets; (8) regulation of
building development for residential, commercial and industrial land
improvements; (9) control of subdivision or building (except for
agricultural purposes) in flood plain areas of streams and drainage
courses, and on unsafe land areas; (10) preservation of outstanding
natural or cultural features and historic sites or structures; (11)
control of soil erosion during land development and building con-
struction; or (12) other benefits to the health, comfort, safety, or
welfare of the present and future population of the county.

(b) Such regulations shall provide standards and criteria for
preparing storm water run-off calculations and drainage structure
design, for reservation of storm easements and for the fifty year
flood plain to the county and for the installation or construction by
any owner or developer of residential, commercial, industrial or in-
stitutional property of all storm water or surface drainage systems
on-site to carry water coming onto and through the property.

[b] (c) Such regulations may also include provision as to the
extent to which streets and other ways shall be graded and improved
and to which water and sewer and other utility water mains, piping,
or other facilities shall be installed as a condition precedent to the
approval of the plat. The regulations or practice of the Planning
Commission may provide for a tentative approval of the plat previous
to such installation; but any such tentative approval shall be revoca-
ble and shall not be entered on the plat. In lieu of the completion of
such improvements, except where water mains and appurtenances or
sewerage facilities are to be installed prior to the final approval of
the plat, the Planning Commission shall require the applicant to
deliver to the County Commissioners a certified check or a bond
with corporate surety to secure to the County the actual construction
and installation costs of such improvements at a time, and according
to specifications fixed by, or in accordance with regulations of the
Planning Commission; and in the event water mains and appurte-
nances or sewerage facilities are to be installed in any subdivision,
the same shall not be finally approved by the Planning Commission