O-82-967 - 8/26/1982ORDINANCE NO.
67 te
AN ORDINANCE AMENDING THE STORMWATER DRAINAGE
POLICY ADOPTED IN ORDINANCE NO. 951 AND AMENDING
CHAPTER 3., SECTION 9.0.(f) CODE OF ORDINANCE, CITY
OF ROUND ROCK, TEXAS.
BE IT ORDAINED BY THE COUNCIL OF THE CITY OF ROUND ROCK,
TEXAS,
I.
That the Stormwater Drainage Policy adopted in Ordinance
No. 951 is amended so that Section I.A.4 of said ordinance is
hereby amended to read as follows:
4. All development establishing impervious cover or
otherwise modifying an existing site shall
incorporate facilities to prevent any increase
in the peak rate of runoff from a 25 -year
frequency storm. Impervious cover is defined as
man made or constructed coverage of the natural
ground surface with roofs, parking lots,
streets, drives, etc. The City Engineer shall be
authorized to waive this requirement under one
or more of the following circumstances:
a. Approved off-site storage is provided for the
required regulation of peak flows.
b. Construction of a single or two-family
residential structure on any legally platted
lot creates no more impervious ground cover
than 30% of the gross lot surface area.
c. Certified engineering data and calculations
are presented which demonstrate the absence
of adverse impact on all downstream convey-
ances and property between the proposed
development and the receiving major stream. A
"major stream" shall be defined as a water
course draining 50 or more acres.
d. Certified engineering data and calculations
are presented which fully describe, explain
and justify recommended alternatives.
Waiver of this requirement for any reason shall
not relieve the owner of responsibility under
civil law to adjacent and downstream property
owners.
II.
That Chapter 3. Section 9.0.(f), Code of Ordinances,
City of Round Rock, Texas is hereby amended to read as
follows:
(f) All development establishing impervious cover
or otherwise modifying an existing site shall
incorporate facilities to prevent any increase
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in the peak rate of runoff from a 25 -year
frequency storm. Impervious cover is defined as
man made or constructed coverage of the natural
ground surface with roofs, parking lots,
streets, drives, etc. The City Engineer shall
be authorized to waive this requirement under
one or more of the following circumstances:
(i) Approved off-site storage is provided for
the required regulation of peak flows.
(ii) Construction of a single or two-family
residential structure on any legally platted
lot creates no more impervious ground cover
than 30% of the gross lot surface area.
(iii) Certified engineering data and calculations
are presented which demonstrate the absence
of adverse impact on all downstream convey-
ances and property between the proposed
development and the receiving major stream.
A "major stream" shall be defined as a water
course draining 50 or more acres.
(iv) Certified engineering data and calculations
are presented which fully describe, explain
and justify recommended alternatives.
Waiver of this requirement for any reason shall
not relieve the owner of responsibility under
civil law to adjacent and downstream property
owners.
III.
A. All ordinances, parts of ordinances, or resolutions
in conflict herewith are expressly repealed.
B. The invalidity of any section or provision of this
ordinance shall not invalidate other sections or provisions
thereof.
(Mark through the following alternative that is not appli-
cable)
Alternative 1.
By motion duly made, seconded and passed with an affirma-
tive vote of all the Council members present, the requirement
for reading this ordinance on two separate days was dispensed
with.
/)/ Tfl
READ, PASSED, and ADOPTED on first reading this Q[(p
day of ,(QALtt, , 19 f .
Alternative 2.
READ and APPROVED on first reading this the day
of , 19
READ, APPROVED and ADOPTED on second reading this
the day of
ATTEST:
, 19
LA" RY L. ' •NN , Madr
City of Round Rock, Texas