Where does our water come from?

Greater Vancouver's water cornes from
rain and snowmelt that is stored in three
mountain reservoirs — Capilano, ;
Seymour and Coquitlam. The Coquitlam
reservoir is the Jargest source, but the
GVRD shares this water with BC Hydro
and must pay BC Hydro for some of the
water.

is there enough water?

Yes and no. While it rains a fot here, the
three mountain reservoirs are only large
enough to store a sufficient supply of
water for another 10 years. By the year
2005, we will need to expand storage by
building a new, higher Seymour Falls
Damn or by negotiating with BC Hydro for

. fights to more Coquitlam reservoir water.
Aggressive water conservation meas-
ures could help to delay this by several
years, however this choice is also
related to water quality and earthquake
upgrading.

Why are we concerned about
future water supply when itr rains
so much here? °

Most rain falls during the fall, winter and

spring when demand for water is low.

-.. Because the GVRD has limited storage.
capacity, much of the water that falls in

... this fow-demand period cannot be
. stored: In the: summer, high demand

strains.our, limited storage. reserves.

The Lower
‘Mainland’ Ss
first water. main

s built in 1889

Since the Seymour Fails Dam
does not meet modern earthquake
Standards what can be done to
make it safer?

The existing dam can be upgraded to
modern earthquake standards or a new,
higher, seismically sound dam can be
constructed. Construction of a new dam
would address two concerns: it would
ensure seismic stability and would
provide more storage.

Construction of a new dam will cost $90
million, while seismic upgrading of the
present dam will cost approximately $18
million,

is the water safe to drink?

There have been no confirmed health
problems related to the quality of this
region's drinking water. However, the

- water does not consistently meet gov-

ernment standards and the risk of

- waterborne disease will persist if steps

are not taken to ensure that the water is
safequarded.

How is the water treated now?

The water is run through a coarse
screening system and is chlorinated at
all three sources (primary disinfection)
as it enters the regional distribution
system.

Water Quality Problems & Solutions

Waterborne | Cysts ate olten detected
Disease in the water system at

(Giardiasis low levels
potential)

Bacterial feveis are too
high; occurence exceeds
standards; disinfectant
depletes along system

Colifo7m
Bacteria

Turbidity Often too high,
“ iness especially at Capilano &
(Cloud ) Seymour. High turbidity

Solution

Kill the cysts with a

simary disinfectant at
low turbidity and remove
them with fillration at
higher turbidity

Provide secondary
disinfectant — either
chlorine or chloramine

throughout the system

Draw from cleaner
source and {iter turbid
source

GVRD Option

eUse Chlorine disinfectant
«Filter Seymour
«Fitter Capilano

*Rechlorinate or
Chioraminate

*Shut down the source
and use Westerly -
Transfer as an interim

. interferes with
disinfection

Natural acidity causes
corrosion of metal pipes
and faucets

Corrosive
Water

Wilf the GVRD add a disinfectant
in addition to the chlorine that is
already added at source (near the
reservoirs)?

Yes. Secondary disinfection (the addition
of chlorine or chloramine) is needed to
safeguard drinking water in the distribu-
tion system. A primary disinfectant such
as chlorine will sti! be added at source.

How will the water taste after a
secondary disinfectant is added?.

lf rechlorination is selected, most areas.
will have a higher potential for chlorinous
tasting water, especially near
rechlorination stations. Chloramination
will have a less chiorinous taste.

Do chiorine and chloramine cause
cancer?

There is no evidence that.chlorine or
chloramine alone are carcinogenic at.
concentrations typically used in drinking
water systems. The combination of
chlorine ana ;satural organics in the
water (such as decaying vegetation) do -
combine to form compounds known as

#s|. disinfection by-products, which have

Greater Vancouver's
Water System
serves more than
1.6 million people

been linked, using very high doses, to
cancer in laboratory animals. Acceptable
limits for these by-products are set out in
the Canadian Drinking Water Guidelines.
Chloramine produces significantly lower
levels of disinfection by-products than
chlorine dees.

Raise the pH of the
water

solution only

Filter Seymour
*Filter Capilano

eAdd minerals
to reduce corrosion
(carbonate)

Why not eliminate all chlorine to

avoid the cancer risk?

Health Canada and other health agen-
cies throughout the world maintain that
the risk of waterborne disease resulting:

frorn untreated water is of much greater:
_ concern than the very smail risk of

cancer associated with chlorination. «

Which secondary disinfectant

option do health officials preter? °

The following is an excerpt froma letter.
sent to the GVRD from the metropolitan
Medical Health Officers: :

“Since chloramination appears to give :
the best tasting water, will adequately
provide good disinfection, wiil meet the
(guidelines for disinfection by- products).
and will delay or reduce the need for’.
filtration, the Medical Health Officers’ -
unanimously support chioramination as °
the future secondary disinfection proc-
ess for the GVRD”. e .

Are there environmental impacts
associated with chloramine and ;
rechlorination? :

Both chloramine. and chiorine can kill

.. fish if treated water is released into a::

fish-bearing stream. Both are toxic to:
fish because they damage ‘the gills of
fish, preventing the ‘transfer of oxygen.
from the water to he bicod stream.

Chlorine diss ipat: os more quickly: and i is
unlikely to kill as many fish as ,
chloramine. ;

aos!

Chiorine & Chloramine Comparison.

Issues

Drinking Water
(Health) Guidelines
by-products

Environmental
Risk

Aesthetic Taste‘Odor
Costs:
Capital.

Annual Operation
& Maintenance

Filtration

$40 - $50 million
$3 - $5 million

Coquitlam

Environmental Up to $55 million

Response
Implementation

The Waier Distribution
System covers a land
_area of more than
2;000 sq. km.

Rechlorination
Fair to Good, Filtration may be
required to control disinfection

Low to severe depending on
conditions - Dept. of Fisheries -
prosecution potential is low

$360 millisn more for filtering

Chioramination.

Good. Filtration not required tn: :
control disinfection by-products

1 to 20 times more than - :
rechiorination. Dept. of Fisheries”.
prosecution potential is high as some | .
fish kills will undoubtedly occur.

Chiorinous taste Almost no {laste

$1 - $2 million

$500,060 “$600. isiele) of

Filtering Coquitlam not required

Up to $70 million

& - 10 years. 50 - 60 rechiorination| 3 years. 3 chloramination stations
Stations throughout region

at sources

The three: -
watersheds cover
an area of |
585 square | kilometres