r'

REPORT TO

HUGHES PROPEXTIES LTD.

ON GROUNDWATER ,HYDROLOGY STUDY FOR

SITES ON HIGHWAY 97 NORTH

KELOWNA, BRITISH COLUMBIA

P r o j e c t Number I 7419/2 Report Date D i s t r i b u t i o n

r September 5, 1974 : Hughes P r o p e r t i e s Ltd.,2 copies

South Okanagan Heal th Uni t , 2 copies South Okanagan Union Board of Heal th , 1 copy Associated Geotechnical Consul tants , 2 cop ie s

Associated Geotechnical Consultants PROFESSIONAL ENGINEERS

September 5 , 1974

Hughes P r o p e r t i e s L t d . , 2417A Harvey Ave., Keloma, B.C.

At tent ion: M r . R . B. Hughes

Dear S i r s :

Re: Sewage Disposal Permit Appeal

I n accordance with your reques t , Associated Geotechnical Consul tants

c a r r i e d out a groundwater study a t t h e above s i te .

a summary of our f indings.

Th i s r e p o r t con ta ins

Applicat ions made by Hughes P rope r t i e s Ltd . and Braelyn Developnent L t d .

t o t h e South Okanagan Heal th Unit on J u l y 25, 1974, for sewage d i sposa l

permits f o r two adjacent l o t s were rejected on J u l y 29, 19’74.

a r e loca ted on t h e e a s t s i d e of Highway 97 North, Kelowna, near i ts

i n t e r s e c t i o n with Dilworth Road as shown on Figtire 1.

These l o t s

The purpose of our involvement was t o i d e n t i f y t h e groundwater regime i n

t h e area beneath t h e s i te . This data was then t o be s t u d i e d t o a s s e s s t h e

v a l i d i t y of ob jec t ions r a i s e d by t h e l o c a l a u t h o r i t i e s t o t h e d ischarge of

dones t ic sewage i n t o a ground absorp t ion f i e l d at t h i s s i te .

GROITNDWATE3 & SOILS DATA

The s i t e was v i s i t e d on August 6, 1974, by t h e undersigned. An earlier

ASSOCIATED GEOTECHNICAL CONSULTANTS LTD.. 1256 W. PENDER ST.. VANCOUVER, B.C., V6E 2S8 685-271 1

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v i s i t by n connection with a s i t e s o i l s i nves t iga t ion has

been repor ted sepa ra t e ly (our r e p o r t da ted Yarch 11, 1974).

v i s i t was f o r t h e purpose of acqu i r ing t h e s o i l and groundwater data

r equ i r ed f o r foundation design of t h e s t ruc tu res .

by was so le ly f o r t h e purpose of co l l ec t ing d a t a on groundwater

observat ions i n t h e v i c i n i t y of t h e s i te .

t h e s t r u c t u r e on t h e south l o t uas p a r t i a l l y b u i l t .

The subsequent v i s i t

A t t h e time of t h e second v i s i t

The part of Kelowna i n which t h e l o t s a r e s i t u a t e d is under la in by

a l l u v i a l fan depos i t s .

foundat ion inves t iga t ion gene ra l ly cons is ted of 2 f t . t o 4 f t , of sand

and s i l t y sand containing gravel .

of sand and g rave l with some cobbles and occasional boulders.

The s u b s o i l condi t ions exposed dur ing t h e

This depos i t is under la in by a s t ra tum

Tour piezometers have been i n s t a l l e d by t h e firm of S. R , Leggett &

Associates f o r t h e purpose of groundwater monitoring. Readings of water

l e v e l s wi th in t h e s e devices have been taken by t h e same surveying company

at i n t e r v a l s between Ju ly 7, 1974, and t h e present time.

I n add i t ion t o e s t ab l i sh ing t h e water l e v e l s at t h e piezometer l oca t ions ,

on Aumst 27, 1974, t h e surveyors determined water l e v e l s at t h e c l o s e s t

p o i n t s of t l i s s ion Creek and M i l l Creek t o t h e s i te .

and t h e s i t e piezometers were reduced t o Geodetic da tu1 t o accommodate

r e fe rence t o groundwater data from o the r sources.

The creek water l e v e l s

Tests were performed on piezometers #1 and #2 on August 6 , 1974, and on

piezometers #3 and #4 on August 27, 1974, by Leggett & Associates , The

procedure cons is ted of f a l l i n g head tests which were intended t o determine

whether t h e piezometers were plugged o r were f r e e l y responsive t o

s33

s33

s33

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f l u c t u a t i o n s i n groundwater l e v e l .

t h a t piezometers #1, #3 and f4 were respons ive but #2 was plugged. The

readings from piezometer #3 were discounted because t h e water l e v e l was

found t o be below t h e s o i l l e v e l wi th in t h e hole. The above data were

used t o e s t a b l i s h t h e groundwater regime i n t h e area between Mission

Creek and M i l l Creek near t h e s i te .

The r e s u l t s of t h i s work ind ica t ed

GR OU NDWAT E 3 REG1 ME

The groundwater a n a l y s i s i n d i c a t e s a r e g i o n a l hydraul ic g rad ien t (i) i n

a d i r e c t i o n South 70' West.

computed as i = 8.6 x

grad ien t between t h e s i t e and mean water l e v e l a t Okanagan Lake,

i = 5.8 x 10

The magnitude of t h i s g rad ien t has been - .

This compares favourably with t h e o v e r a l l

-3 . As a check on t h e s e r e s u l t s t h e computed g rad ien t between t h e c reeks was

used t o p r e d i c t t h e water l e v e l i n piezometer #lo

a c t u a l l y recorded va lues were 1213.70 f t . and 1213.65 f t . , respec t ive ly .

T h i s shows very close agreement and l e n d s confidence t o t h e o v e r a l l

conclusions wi th regard t o t h e groundwater regime.

The predic ted and

The impl i ca t ion of t h i s r e s u l t is tlpt e f f l u e n t e n t e r i n g t h e groundwater

from a n absorp t ion f ie ld loca ted between t h e c reeks would flow i n a

wes ter ly direction ( S r / O W ) , i.e. approximately parallel t o t h e f lows of

t h e two creeks.

tendency t o flow towards M i l l Creek under t h e in f luence of t h e h igher

water l e v e l s i n Yission Creek as t h e component of hydraul ic g rad ien t i n

t h a t d i r e c t i o n is only 1.9 x

permeabi l i ty of 10'' cm/sec. f o r t h e s o i l strata beneath t h e watertable,

Water i n t h e groundwater system would not have a marked \

Using an average c o e f f i c i e n t of

I

\

4

( t h i s is a high es t imate f o r t h e a c t u a l s o i l cond i t ions i n t h i s area),

t h e time requ i r ed f o r e f f l u e n t l eav ing t h e s i t e t o r each M i l l Creek was

computed.. It has been c a l c u l a t e d t h a t i n excess of 8 y e a r s would be

require3 f o r e f f l u e n t t r a v e l l i n g i n t h e groundwater t o reach t h e c reek

at its nea res t po in t t o t h e s i te .

OBJECTIONS RAISED BY SOUTH OKANAGAN HZALTH IJNIT

The main ob jec t ions raised t o permit approval i n t h e South Okanagan

Health Uni t l e t t e r of J u l y 29, 1974, are d iscussed below i n t h e contex t

of information gained du r ing t h e r e c e n t groundwater s tudy as w e l l as our

e a r l i e r foundat ion inves t iga t ion .

Low Nutr ient Rc Water Retent ion

Low n u t r i e n t and water r e t e n t i o n above t h e watertable would be c o n s i s t e n t

with coarse gra ined s o i l s such as gravels . We fee l t h a t t h i s is

necessar i ly t h e case with s o i l s having p e r c o l a t i o n rates which are

comfortably wi th in t h e specified rate of 30 min./in.

provides fo r pe rco la t ion rates as low as 1 min./in. and appa ren t ly

considers lower numbers (rapid d i s s i p a t i o n of water) more desirable

than higher numbers (low permeabi l i ty ) .

t h a t t h e area of absorp t ion f ie ld requ i r ed by t h e Act f o r 1 min./in.

perco la t ion rate i s only 2% of t h a t r equ i r ed f o r 30 in./min.

The Heal th Act

Th i s is obvious from t h e fact

If h izher water and n u t r i e n t r e t e n t i o n are desired t h i s can be accomplished

by importing s o i l of a f i n e r g rada t ion than t h e n a t i v e material t o t h e

a r e a and p l ac ing it beneath t h e abso rp t ion field.

"Fliishi ng Action"

It is understood t h a t t h e r e is concern r ega rd ing t h e e f f e c t of "f lushing"

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a c t i o n from Yission Creek on t h e contaminating inf luence of t h e e f f l u e n t .

We understand t h e term "flushing" t o i n d i c a t e f l u c t u a t i o n s i n c reek water

l e v e l . The only in f luence f l u c t u a t i o n s i n Fiission Creek water l e v e l

could have on t h e r a t e of e f f l u e n t movement towards M i l l Creek would

be t o cause a n increase i n t h e hydraul ic grad ien t i n t h a t d i r e c t i o n .

F luc tua t ing water l e v e l s , because of t h e i r s h o r t du ra t ion ( r e l a t i v e t o

t r a v e l t ime) , a r e not s i g n i f i c a n t i n t h i s s i t u a t i o n and t h e c o n t r o l l i n g

f a c t o r would be t h e seasonal mean water l eve l s . However, as an example,

t h e effect of a permanent water l e v e l i nc rease of 5 f t . i n Mission Creek

was computed,

t r a v e l time from t h e s i t e t o M i l l Creek from about 8 yea r s t o 5 years ,

This , we f e e l , does not ma te r i a l ly a l ter t h e inf luence of t h e e f f l u e n t

on M i l l Creek.

Such a change would r e s u l t i n a reduct ion i n t h e groundwater

Highest Recorded Water Table

The h ighes t piezometric l e v e l recorded on s i t e i n a func t ioning u n i t

was t h a t measured i n piezometer #4 on August 8, 1974, when water was

encountered a t 5.4 f t . below ground l eve l . Th i s l e v e l is wl th in t h e

permiss ib le groundwater l e v e l f o r a d i sposa l s i t e .

a d d i t i o n a l dep th between ground l e v e l and groundwater su r face be requ i r ed

t h i s can be achieved by l o c a t i n g t h e absorp t ion f i e l d f u r t h e r west than

piezometer ,#k.

hor i zon ta l movement towards t h e west from piezometer #4.

However, should

About 1 f t . of depth w i l l be gained f o r each 120 f t .

Old Creek Bed

It has been suggested t h a t t h e old creek bed which passed near t h e

north boundary of t he s i t e would increase t h e rate a t which e f f l u e n t

6

could reach Xi11 Creek. The bed of t h i s creek was examined ou t s ide

t h e proper ty l i m i t s where it xix s t i l l un f i l l ed . The bed is s i l t

covered and i s t h e r e f o r e less pervious and less l i k e l y t o t ransmi t

f low than t h e surrounding ground, which i n our s i t e inves t iga t ion was

found t o be sand and g rave l with cobbles and boulders up t o 18 i n .

diameter . On t h e basis of t h e foregoing r e s u l t s and conclusions we feel t h a t

t h e ob jec t ions put forward by t h e South Okanagan Health Unit are

content ious and , in part , without basis, Accordingly, on August 7,

1974, w e informed t h e South Okanagan Union Board of Health of OLW

opinion t h a t t h e s i t e conforms with t h e r egu la t ions of t h e Heal th

A c t and of your wish t o appeal t h e dec is ion of t h e Medical Heal th

Officer.

We would be pleased t o discuss t h e conten ts of t h i s r e p o r t with any

i n t e r e s t e d par ty .

Yours t r u l y ,

_.

I S I T E P L A N lFiGURE ’

--SOUTH SITE

SCALE : 1 in. to 500 f t . approx.

$- PlEZOMETER

& WATER LEVEL

Associated Geotechnical Consultants

.'iE A L f H C EN1 R E S :

RUTLAND, O.C.

. KELOWNA, O.C.

PEACHLANO, O.C.

SUMMERLANO, B.C.

PENTICTON, O.C.

O L I V E R , B.C.

osoYoos, 0.c.

KEREMEOS. 0. C

PRINCETON, O.C.

December 24, 1974 '/

Mr. Ear l Anthony, P.F., Regional Engineer, Water Rights Branch, 1905 Kent Road, Keloma, B.C.

ADDRESS O F F I C I A L C O M M U N I C A T I O N S TO:

D I R E C T O R , S O U T H O K A N A C A N H E A L T H UNIT 390 Q U E E N S W A Y . K E L O W N A , B . C .

VlY 6S7

SOUTH OKANAGAN HEALTH UNIT

Dear S i r :

Re: Sewage and Drainage - Hughes' Property Shopping Centre - Highway 97

On December 20th, 1974, Fred Alcock, Senior Publ ic Health Inspector and myself met with you t o d i scuss t h e p o t e n t i a l s emge and drainage problems i n connection 166th t h e proposed development of a ground d i s A o s a l system for t h e Hughes' Shopping Centre Development (adjacent t o t h e Newsom farm).

As t h i s modern shopping cen t r e (Complex -$l) has been constructed i n an o ld water course, which has been used f o r f i f t y yea r s o r more f o r i r r i g a t i o n and/or flood drainage, we would l i k e t h e a s s i s t a n c e of t h e rslat.er Rights Branch t o study t h e following items:

1. S u i t a b i l i t y of t h i s property f o r a major shopping cen t r e and t h e proposed i n s t a l l a t i o n of a ground d i sposa l system as well as t h e d isposa l of parking l o t drainage water.

2. High water l e v e l s throughout t h i s a rea i n l a t e winter and spr ing time and t h e i r s ign i f i cance i n r e l a t i o n t o t h e fou r foot r u l e f o r ground d i sposa l systems.

3. Map of t h e Area ou t l in ing major s t r u c t u r e s and r e l a t ionsh ips e.g., Mission Creek, M i l l Creek, and t h e s e v e r a l sur face drainage water courses, as wel l a s s i t i n g t h e shopping cen t r e complex and i t s proposed parking areas.

4. Water t a b l e gradients.

The S.O.H.U. vould be wi l l i ng t o provide one of our L.I.P. workers t o record water t a b l e l e v e l s i n t h e fou r t o s i x proposed t e s t holes t h a t you have suggested a s observat ion po in t s fo r thespr ing melt and t h e sp r ing run-off, and perhaps throughout a twelve month period.

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!4e thank you f o r your continued cooperation i n a team approach t o mutual environmental - heal th problems i n the Okanagan and Similkameen VP ? p a

Yours t r u l y ,

D. A. Clarke, M.D., M.P.H., Medical Health Officer.

DAC : mp

cc: - Fred Alcock, S/PHI - Wayne McGrath, Regional Env. Health

- Harold Cawston, PHI Ehgineer, Vernon

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1905 Kent b a d , Keloma VlY 7S4 Jan- 21, 1975.

Dear Sir:

Reference is &e to your letter of Dsomber 24, 1974 regarding your requeet for my asrristance in dealing with the problem associated with the development of a ground d i s p o s s l aystem for the above property. Z-have had an opportunity t o review this matter rMd t o conaider a report on thia arb&ct pret- wed @ ASSoCiSted G s a t e C h n i d COn6UltM;tS dated 5, 1974.

€’ran a atudgr of t h i a Wonnation, I have oonalw€ai that there is b u f f i c i e n t data available at this t b a t o provM6 cuqxrehenalve ~immr6 t o the queationr posed i n your letter. Tho Malysl6 urdertalcen by Aesociated Geotechnical Conaultrprts i8 baed on a very ehort period of‘ r 0 C o r d 6 during what could be 8 non-critical period of the year, In addition, the subterran0 of thie area is very uanplex url does not l a d itQslf to 8 i ~ 4 h analysis. The area has experienced an eventful gealogica3 psSt cmd the lo1108 are often die- C O ? l t ~ U O U S erd ir2”6-.

In the recent psust, the sit@ of this shopping uantre hrrs beon very wet. by ditches whiah tended to artifLCally raim the groMd water table. the tat1 water franr i r w t i o n ditches wa8 dumped into D r y Creek whioh floua through or edjscent t o the site,

UW. This chrvlge Zn lsnd w e bas raoulted in e ahango in the runoff pattern of surrounding laslds axxi prhape a reduction in the qnmtlty of water available to maintain the current tater table, net effect of thew changes has not been documented .

hrbg the f l lWb hll O f tM6 C m t U r g , th b u r r o r m d ~ -8 w8m hTlgatsd In additlon,

In 1973 the UIM of thew ditches w discontinued and the 6 m u d b g lrnd U 6 e h W ChW@ t o kpb F d d e a f s l Md C a m p s r G h l

cant hued. . . . .2/

I

Pago two

Dr. Do Clarke, H.D., H.P.H., M d l c S l d d t h Officer, South 0- I W t h Ut,

22. 1975

(3) As m n us water appwws in ths obsiennctfon w e l l , it is recl.arapendid that; dye be put d m the well every 7 &y8. It h rrlsa l-eccmmdeul that once a weak ample8 be taken W m the foU.c&q pM;e BI1ci analgzed for traceu of tbe dye:

(1) D r y Crersk at ita mouth

(2) Mu. creek, bdow t h mouth of aitche Eroaik

coO.rtinuad0 0 0 . . e e . . 0 . . .3/