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Sie Taga RENN FMR td AE

SENN Toy CET,

ee eS te ne a oe ee NTR it Bie ee

TO: Members of Council . March 8th, 1973
FROM: Mayor L.B. Scott ir x q fl Py & ‘a fl q
4 i i ‘<1
| VU OUI
Re: G.V.R.D. Meeting - March 7th, 1973 3 é

MAR 421975
The Board hag approved a requesc from Delta Municipality that a complete hydrological Sa'tys?s be made

of all land within the Regional District to determine the effects of furcher intensified development and the
capability of al1 lands to handle future drainage needs, including storm water flows; and further that such a
study include consideration of building designs which would assist in restricting the rapid runoff caused by
storm conditions.

The Sewerage District is the proper legal bedy to consider this request. The objects of the Severage
and Drainage District as laid out in its legislation is che construction, maintenance, Operation, and administra
tion of the major sewerage and drainage facilities of the area in substantial accordance with the awn Report:

among its objectives is -

"The investigation and evaluation of possible methods of providing sterm water drainage for the entire

area. Such study includes the determination of the moat appropriate type of drainage works for each

drainage basis. Anticipated future development within each such basis will in large measure determine

the nature of such drainage facilities." .

This study was carried out more than twenty years ago and the development of the area at that time did
not apparently warrant the detail Studies which may now seem appropriate. Since the publishing of the Rawn Report
the Sewerage District has carried out limited studies in certain Specific areas such as for the flood control work.
for Mosquito Creek, Hastings Creek, and Capilano River ia North Vancouver which were also constructed by the
District, and for four of the major creeks in West Vancouver. The District has also administered the Still Creck-_
Burnaby Lake-Brunette River drainage facilities as well as Musqueam Creek and the drainage shaft in the University

Endowment Lands. It also maintains rainfall gauges throughout the area. .

In light of the vase developments in area since the Rawn Report work and the seriousness of vecent flocd~

ing incidents, ic is time that the Rawn Report covering drainage of the Greater Vancouver area be reviewed and up-
dated in the same way thae the sewerage system covered in the Rawn Report was updated in 1968 and 1969.

The following terms of reference have been prepared. Tre study will concern itself with the drainage re-
quirements of the Greater Vancouver Region under the following headings:

L Past History and Existing Oblieations

The past history of drainasce undertakings to be reviewed and existing obligations catalogued.
Ir Drainage Area

(a) Through studies of existing topographical information identify major drainage areas in the Region and
delineate the major drainare facilities in these areas.

(b) Obtain and study data on previous flooding and flood damage related to the major drainage facilities.

Itz Desien Criteria

(a) Rainfall analysis: in co-operation with Environment Canada review existing data from Sewerage District
and other rainfall records and through statiscical analysis prepare or update intensity duration curves
for periods of from 5 minutes to 48 hours for 2 years to 25 years summer and winter frequency for design

purposes for various parts of the Districr. ceseetont'd. Page - 2 ~