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Full text of "Snow survey report, east and middle Oakville Creeks drainage basin, 1968-1969"

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.ON) 




Water mansgement in Ontario 



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Onlario 

Water Resources 

Corrifflissioiitr ^'-v^ 
MAR 15 1971 







J^m^r Resources 
Bulletin 4-1 

J2limatic series 



SNOW SURVEY 
REPORT 

EAST AND MIDDLE 
OAKVILLE CREEKS 
DRAINAGE BASIN 
1968-1969 



IHD 

1965 



CANADA iy74 

„.;::« DH I 



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WATER RESOURCES 
BULLETIN 4- 1 
Climatic series 



SNOW SURVEY REPORT 

EAST AND MIDDLE 
OAKVILLE CREEKS 
DRAINAGE BASIN 

1968—1969 



By 
L.A.Logan 



ONTARIO WATER RESOURCES COMMISSION 
DIVISION OF WATER RESOURCES 



TORONTO 



ONTARIO 



1971 



TABLE OF CONTENTS 



ACKNOWLEDGEMENT 
ABSTRACT ...... 

INTRODUCTION . . , 
OBJECTIVES ,,-..: 



BASIC CONCEPTS ...,.., ...... 

Assumptions ....... . .•.••.•. • • • 

Statistical Procedures ........ 



FIELD INVESTIGATION . . 

Snow Survey Network , , , 

Snow- Samp ling EqiiipiDent .,,,....,.......,..«. 

Data Collection .............. . ............ . . 

SNOW COURSE EVALUATION ....... 

Single- Index Ranking ., 

Multiple- Indices Ranking 

SNOW DEPTH AND WATER EQUIVALENT .... , . .... . . . . , , 

Areal Variability 

Empirical Relationship 

PRECIPITATION (SNOW) STORAGE ESTIMATES ....,.,. , 
Arithmetic Method ..,,.,,..,,,,.,,.,,.,.,.,.. 

Thiessen Method , , , , , , , 

Area-Elevation Method .................... . . , 

Isohyetal Method 



CONCLUSIONS , . . 
RECOMMENDATIONS 
BIBLIOGRAPHY . . 



APPENDICES -DATA SIMIARIES AND RESULTS 

OF ANALYSES 

Appendix I .,,.....,,,,.,,,.,.,.., 

Appendix II ....,.................,,,,, 

Appendix III 

Appendix IV ............................... • • 



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38 

39 



42 

43 
56 
67 
71 



ACKNOWLEDGEMENT 

"Xtie snow survey prograni is being carried out 
as part of the hydrologlc studies being undertaken 
by the River Basin Research Branch of the Division of 
Water Resources . 

Mr. D, Puccini j Engineer, established the 
snow survey network; collection of data and the 
preparation of a preliminary draft snow survey report 
was carried out by Mr. A. Sweetman, Engineer, with the 
assistance of Mr. D. Donohue, Technician of the River 
Basin Research Branch, 



ABSTRACT 

Snow-cover Investlgatioii in the East and Middle 
Oakvllle creeks drainage basin is one of several phases of 
hydro logic studies being carried out by the Division of Water 
Eesources , Ontario Water Resources Comnissionp as part of 
Its International Hydrological Decade representative basin 
program. The snow survey data collection program. Initiated 
in the winter season of 1968-1969, forms part of a precursory 
study for arriving at aeceptable hydrologic parameters for 
use in evaluating general water balances in the basin. The 
established sampling network facilitated the collection of 
an adequate quantity of data, for use In estimating basin 
snowpack index water equivalents and the extent of snow 
cover in the specific areas . The gravimetric method of 
sampling employed provides the measurements of snow depth, 
core length and weight measurenient of equivalent depth of 
melt water. Statistical evaluation of the data established 
the accuracy and reliability of the sampling, the acceptable 
quality of the data and the adequacy of the designed 
network. Further reliability and consistency of the data 
were ascertained through a simple linear regression, with 
verification that under the prevalUng conditions of the 
Investigation, the graviinetric technique was adequate 

- 11 - 



for providing sample estimates of the snowpack water 
equivalents . The adequacy of the s^npllng network was 
substantiated by the comparison of estimates of the basin 
snowpack indices determined by different methods of data 
evaluation. 



- ill - 



SNOW SURVEY REPORT 

If 

EAST AND MIDDLE OAK¥ILLE CREEKS DRAINAGE BASIN 

1968-1969 

INTRODUCTION 

The Ontario Water Resoiirces Commission 
Initiated the stody of winter precipitation and snow 
cover in the East and Middle Oakvllle creeks International 
Hydro logical Decade (I.H.D.) representative drainage 
basin In the winter of 1968. The drainage basing located 

in southern Ontario, covers an area of 76 square miles. 

o 
Its boundaries extend approximately between 79 45 'W and 

80° O'W longitude and 43° 20 'N and 43° 38 'N latitude. 
The topography has moderate slopes, with Increased surface 
nndtilations in the most elevated areas. The elevation 
ranges from 1,200 feet above sea level at the main stream 
source to 600 feet above sea level at the lowest streamflow 
gauging station. Approximately 28 per cent of the drainage 
area is enclosed between elevation 800 feet and 1,200 
feet above sea level. The vegetative covers are pre- 
dominantly crops and pastures, with sparse distribution 
of improved and unimproved forested areas. 



- 1 - 



Snow accumulation and complete areal snow 
cover are normal events in the basin for three to five 
months of the year. From the condition of the snowpack 
(accunulated snow) , a measure of the winter precipitation 
amounts in the basin can be estimated. 

Itn approach towards providing estimates of 
the basin snowpack conditions at a given time is by 
way of snow survey investigations . Snow surveys are 
normally carried out by way of data collection from a 
sampling network comprised of a number of snow courses « 
The gravimetric method, which entails weight measure- 
ments of core samples from the snowpack, is one of 
several sampling techniques employed for obtaining the 
data necessary for evaluating the basin snowpack condition, 
This sampling technique provides an estijnate of the 
areal extent of the basin snow cover, an indication of 
the trend of snow accumulation and depletion, and an 
index of the basin runoff potential from snowmelt. 

This report deals with preliminary analyses 
for the evaluation of the data collected from the first 
of a series of seasonal snow survey investigations , 
Subsequently, the data will be used in analyses of runoff 
and water balances in the basin. 



- 2 - 



OBJECTIVES 

The basic objectives which characterize the 
snow survey Investigation may be summarized as follows; 

1. To determine the point values of the 
snowpack depth, water equivalent, core 
length, and density for all the selected 
snow courses In the drainage basin. 

2. To determine the uniformity of snow cover 
on each snow course and the adequacy of 
representation of the basin snow cover 

In the designated areas . 

3. To evaluate the comparative reliability and 
quality of the individual point measure- 
ments, as well as the relative reliability 
of the data between the snow courses . 

4. To determine and establish, by a practicable 
and reliable method, satisfactory precipi- 
tation storage estimates or hydrologlc 
Input Indices for the drainage basin for 
the winter precipitation period. 



- 3 - 



BASIC CONCEPTS 

The density of snow may be defined as the 
ratio between the volinne of melt water from a given 
sample of snow and the Initial volume of the sample (7)^. 
For a given snowpack, the density Is known to vary widely 
with time, to vary directly with depth and stratifica- 
tion of the pack, and to exhibit areal variability 
within a region of snow accumulation (1, 4, 5, 9, 14), 

The gravimetric method of sampling attempts 
to provide direct estimates of an index of the water 
stored in the snowpack. From a number of point measure- 
ments of snow depth and water equivalent (equivalent 
depth of melt water, as determined from the weight of 
the sample), an Integrated average of the snowpack water 
equivalent and density may be determined (4, 5, 7), 

By operating with the above -mentioned basic 
relationship between the snowpack indices (depth, water 
equivalent and density) and with the support of a number 
of apparent assumptions, the quality and reliability of 
the data collected may be evaluated analytically. 



* References in Bibliography 



- 4 - 



Assumptions 

Snow deposition on a drainage basin is known 
to be heterogeneous in distribution (5, 13) . It Is, 
therefore, necessary to be aware of the llinttations of 
the method of sampling employed. The successful use 
of the gravimetric method in this investigation is 
subject to a number of limitations . The main purpose ' 
for the summarized assumptions given below is to facilitate 
meaningful and rational physical interpretations of the 
analysed data. The following are assumed: 

I, The selected sampling network provides a 
sufficient nuraber of samples for reliable 
estimates of the basin snowpack indices. 
M:i The large-scale effects of the regional 
orographic factors (elevation, exposure, 
rise and orientation) with respect to storm 
experiences in the basin are general for 
all locations . 
1* The nature of snow deposition and distribu- 
tion at a selected site is influenced 
entirely by the combined effects of the 
local terrain parameters or environmental 
factors, such as vegetation, ground slopes, 

aspects and degree of protection from the wind . 

- 5 - 



4, The average density of the snowpack 
detemlned from the simultaneous point 
measurements of depth and water equivalent, 
on a particular date, represents a constant 
for the basin at that time period. 

5 , The point measurements taken from the 
snowpack on a particular survey represent 
a statistical sample drawn at random from 
a normal finite population. 

Statistical Procedures 

Statistical procedures can be used to 
evaluate the accuracy and limitations of the point 
measurements and the reliability and quality of the 
data for use in obtaining basin snowpack index water 
equivalents . 

By accepting the assumption of normality and 
randomness of a sample, bias introduced into the data 
by selective sampling is neglected; hence, the sampling 
errors and variations of a sample may be determined by 
application of standard statistical equations (6, 8, 11) 
of the forms: 



- 6 - 



1=1 

N 



nh 



(Xi - X) 



N-1 



... (1) 



... (2) 



S 



• ■ • V"*/ 



^ 



... (4) 



where: X - sample average; 

X " 1 point measurement; 

S » standard deviation; 
N - number of observations; 
C • coefficient of variation; 
S~ « standard error of average; 

1 «1, 2, 3,.,,N observations. 

The errors associated with each sample average 
may be determined and examined from confidence limits 
specified by given probability levels. The confidence 
Interval for the population average, ^ , for depth 
or water equivalent^ may be determined from the general 
expression: 

- 7 - 



where t^ ^c# is the value of the standard normal deviate 

at the five per cent probability level for (N-1) degrees 
of freedom (6, 8, 11, 12) , 

By operating with the stated assumption that 
the average density of the snowpack is a constant at a 
specific time, tests for consistency and reliability 
of the data can be carried out by an examination of 
the statistical association between the measured depths 
and water equivalents . These tests can be applied to 
data collected on a particular date from a snowpack of 
a given areal extent. The statistical association 
between the two variables was derived from a developed 
empirical function based on an assumed linear regression 
(8, 11, 12) . Water equivalent, W, is the dependent 
variable and depth, D, the applied independent variable. 
By using the least-square technique with the added assump- 
tion that the origin of the line Is at the point of 
averages (11, 12) , the derived function is of the form: 



Wj, « A + bD ^ 



in which 



# Standard table of 't '-distribution 



- 8 - 



N 
y^ (M^ - W) (D^ - D) 

b - 1^1 ... (6a) 

ir (Di - D)^ 

and 

A - W - bD, ... (6b) 

where W^ Is the predicted estimate of the water equlvalentt 

b the regression coefficient (an estimate of the defined 
constant density), A the intercept on the ordinate. 
In the ease of the regression treatment, the least-square 
derivation for the empirical function obviates the 
assumption of a type of distribution or randomness of 
the data. 

The regression Is distributed with a residual 
variance estimated by: 

2 X (Wl - Wc) 

e - — 

^ N-2 

where S^ Is the standard error of estimate, 
e 

The corresponding variance associated with 

the regression coefficient may be estimated by: 

S^ - ° . •.. (8) 



Ji <°i - ^^' 



where S^ Is the standard error of the regression 
coefficient . 

- 9 - 



Due to practical knowledge of the nature of 
the variables, the line of regression may be forced 
through the origin-, that Is, for D - 0, W - 0. Equation 
(6b) gives an estimate of this condition for the popula- 
tion with estimated variance: 



2 2 

,S,- ™ S 
a e 



1 + 

N N 



m2 



S ^"i ■ 



D) 



... (9) 



mS 



where S^ Is the standard error of the Intercept. 

the practical significance of the regression 

may be determined by the coefficient of determination: 
2 
r^ - 1 - ^ . -25 < r^ 4 1-0 • -.• (W) 



where r is the coefficient of correlation and S^ is 

the standard deviation of the water equivalent. Equation 

2 
(10) indicates that if the computed value of r Is greater 

than or equal to .25 then the regression may be regardad 

as practically significant (11, 12) . 

A test of linearity of the regression, based 

on the 'F' -distribution. Is given by the general form: 
2 



. P(F(1, N-2) >F) <.05, ... (11) 



2/(N-2) 



- 10 - 



5 2 2 
where Sj^ == Sy - S is the variance accounted for by 

the regression. Equation (11) Indicates that the 
linear regression may be regarded as significant If 
the computed F-value Is greater than or equal to the 
corresponding F-value (F) determined from a standard 
table of 'F' -distribution (8, 11) for the defined 
degrees of freedom (1, N-2) at a given probability level 
(P - .05). 

The confidence interval on the population 
regression coefficient,-^ , may be obtained by replac- 
ing // f X, and Sy in equation (5) by^ , b, and S^, 
respectively; similarly for the population intercept, 
oC , the confidence interval may be obtained by replacing 
//, X, and Sy by cC • A and S., respectively. The 

value of the standard normal deviate remains at tQ Q5, 
in this case for (N-2) degrees of freedom. 



- 11 - 



FIELD INVESTIGATION 

With the aid of a topographic map of tha basin, 
a desirable number of snow courses were selected by 
way of an elimination process through field surveys 
and site investigations. Itie implementation of a 
designed sampling program facilitated the collection of 
a desirable quantity of data which were necessary for 
the network evaluation. The sampling equipment employed 
were the conventional tube-type snow samplers (2, 3, 
7, 10). 

Snow Survey Network 

The survey network consists of eight snow 
courses. The basic criteria for selecting these snow 
courses were basin topography and vegetative cover. 
The unique location of the drainage basin within a 
larger geographic region and the relatively graded, 
uniform topography supported the acceptance of the as- 
sumption of the large-scale effect of the regional 
orographic factors with respect to storm experiences 
in the basin. Operating with the above-mentioned 
criteria and assiuiption, eight snow courses were select- 
ed throughout the range of topography and major types 

- 12 - 



of vegetation In the basin. The locations of the 
selected sites are shown on Map 1 of Appendix I. 

The selection of the individual sites for 
each snow course was directed by accepted guidelines 
(3, 5, 10), including conditions such as well-sheltered 
area, well-drained site on clean litter or soil free 
from stumps or debris, uncultivated, and a readily 
accessible location. A standard snow course consists 
of ten sampling points with spacing of 100 feet in a 
straight line. Changes in local ground slopes and 
limited property boundaries necessitated some modifica- 
tions in layout at a few sites . Figures 1 to 8 of 
Appendix I are diagrannnatic sketches of the Individual 
site layouts. 

The network density was approximately one 
snow course per 9 .5 square miles . 

Snow- Samp ling Equipment 

TWO types of snow-samplers were employed, 
the Mount Rose sampler and the MSC Type-I sampler. 
Each sampler consists of a duralumin tube, with a saw- 
toothed cutter as an integral attachment at one end« 
the toothed cutter allows for easy insertion of the 

- 13 - 



tube into the snowpack. Each tube has graduation in 
inches on the outer surface which provides for depth 
measurement to the nearest 0.1 inch. The unit length 
of each Mount Rose sampler tube is 42 Inches with an 
inside diameter of 1.485 inches. The length of the 
MSC Type- I sampler tube Is 43 inches with an inside 
diameter of 2.785 Inches. 

A tubular extensible spring balance was pro- 
vided with the samplers for obtaining a direct estimate 
of the equivalent depth of melt water In each sampled 
core by weighing. The balance has two separate scale 
calibrations, one for each sampler. Unit calibrations, 
weight ^ 1.0 ounce, for the Mount Rose sampler and 
weight * 3.5 ounces for the MSC Type-I sampler, are 
equivalent to a snowpack water equivalent of 1.0' inch. 
The Mount Rose sampler was recommended for sampling in 
a very deep powdery snowpack, while the MSC Type-I was 
recommended for sampling in shallow and less powdery 
snow (3 ) . 

Other accessories were a wire cradle for 
suspending the tube on the balance, a turning and driv- 
ing wrench for operating the sampler, spanner wrenches 
for assembling tube units of the Mount Rose sampler, 
cleaning tools and carrying cases. 

- 14 - 



Da t a Co 1 lee t ton 

Prior to the expected winter precipitation 
period, each selected snow course was prepared for 
observation. Preparations involved checking and staking 
the designed layout and clearing tall grasses and debris 
from within a radius of five to ten feet of each staked 
point . 

It was planned to commence snow surveys 
when snow had accumulated to an estimated depth of two 
inches in the basin, but the first major snowfall 
occurred in early January, 1969, with an accumulation 
of greater than twelve inches . Snow surveys conmienced 
immediately after this major storm event. Subsequent 
surveys were done at least once every two weeks* 

Point measurements obtained at each of the 
ten sampling points on each snow course were: snowpack 
depth, water equivalent and core length. Each core 
sample was obtained by inserting the tube sampler into 
the snowpack, held normal to the ground slope and driven 
to the full extent of the snowpack depth. Table 1 of 
Appendix I shows a compiled, sample, snow survey data 
report sheet. Notes were made on the visual appearance 
of average conditions of the snowpack (e.g. presence 
or absence of crust and ice layers) and of the soil 

- 15 - 



condition beneath the snowpack (e.g. frozen or moist). 
A sumoary of the data collected Is given In Table 2 of 
Appendix I. These are averages of the respective ten- 
point observations, with the corresponding average snow 
density on each snow course. 

During the Initial survey, the Mount Rose 
sampler was employed for stapling In the deep powdery 
snow; the MSC Type-I sampler was employed during all 
subsequent surveys . Observational errors were kept at 
a minimum by strict adherence to the measurement pro- 
cedures. Special efforts were made to minimize the 
wind effect on the spring balance during the weighing 
operations . 



- 16 - 



SNOW COURSE EVALUATION 

The snow courses were compared and evaluated 
on the basis of the variability in accumulation. The 
variations about the average snowpack indices were 
determined statistically and used as measures of the 
snow cover uniformity on the respective snow course. 
A good to near excellent snow course would have the 
least variation about each sample average snowpack index. 

The standard deviation and coefficient of 
variation were computed for each sample size by applying 
the standard equations (1) to (3) on page 7. Tables 1, 
2, 3 and 4 of Appendix II show the computed averages 
and respective deviations for snow depth, water equivalent, • 
core length, and density on each snow course. The 
analysis was done for each survey for the period of 
snowfall. The effects of the local terrain parameters 
on snow deposition appeared to be more appreciable during 
the accumulation period. It is believed that the terrain 
parameters impart similar effects to precipitation experi- 
ences, snow as well as rain, in the basin. These effects on 
snowfall are the more pronounced during the snow accumula- 
tion period. On the other hand during the major snowmelt 
period, the expected differences in melt rates on 
different areas of the basin would introduce variations 

- 17 - 



in the data not accounted for by the effect of terrain 
parameters on snow deposition, Ihe data from this melt 
period were therefore omitted from this analysis. 

Single-Index Ranking 

Field experiences gained in sampling the snowpack 
showed that the possible observational errors associated 
with the measuring of the snowpack Indices were the least 
for snow depth. Consequently, for practical purposes, 
snow depths were regarded as the most accurately measured 
values . This condition therefore qualifies depth as the 
most suitable, single Index for use in comparing snow cover 
variability within and between courses . The variability 
was assessed by an examination of the series of coefficients 
of variation of depth. Table 5 of Appendix 11 shows the 
snow courses ranked according to the increasing order of 
magnitude of the variation coefficients . The table was 
derived by summing the rai^s of each snow course for the 
four survey periods; the group totals were then re-ranked 
to give the most uniform course (highest rank 1) and the 
least uniform course (lowest rank 8) . An examination of 
the results showed that snow course number 8 acquires the 
highest rank and snow course number 4 acquires the lowest 
rank, indicating that the snow cover was the most uniform 

- 18 - 



in depth on snow course number 8^ and least uniform in 
depth on snow course number 4 for the specified accumula- 
tion period. This deduction compares reasonably with field 
observations; that Is, snow course number B satisfied iiost 
of the basic selection requirements for a good snow course, 
whereas snow course number 4 was noticeably the least 
sheltered. Snow courses number 2, 5, and 6 had comparable 
uniform depth of snow cover, and courses number 1, 3, and 
7 had fair to poor coverage. 

Mult iple- Indices Ranking 

In order to test further the degree of vari- 
ability summarized by Table 5 of Appendix II, a multiple 
^ranking procedure was carried out for all the snowpack 
indices , Table 6 of Appandix II gives a summary of the 
multiple ranking. The indices for water equivalent, 
core length, and density were ranked similarly to depth 
(Table 5 of Appendix II) , The grouped totals for each 
index were sunaned and the grand totals were then re-ranked. 
The result did not differ significantly from that of 
the single- index ranking. An examination of the results 
showed that the depth of snow cover on snow course 
number 4 was undoubtedly the least uniform. Using both 
forms of ranking, the same snow courses can be divided 



- 19 - 



into two major groups* The first group, Bnavf courses 
number 1 , 2 , 5 , 6 and 8 can be regarded as the more 
representative of the basin cover. These courses were 
located in the areas of ideal orientation and exposure 
to all forms of precipitation. The second group, 
snow courses nianber 3, 4, and 7 were less representative, 
consisting of courses that were the least sheltered 
and thereby were subjecting the snow cover to sub- 
stantial amounts of wind drift. 



- 20 - 



SMQW DEPTH AND WATER EQiriVALENT 

For the purpose of a group evaluation of the 
data, all of the point measurements from a particular 
survey ware grouped in one sample analysis, excluding 
data from courses with poor measurements (< 50 per cent 
snow covered) • A simple computer program*, based on 
equations (1) to (11) of pages 7 to 10, was utilized to 
perform the statistical analysis. The results of the 
analysis facilitated an examination for the areal varia- 
tions inherent in the snow cover distribution on the 
drainage basin and the degrees of confidence and accuracy 
placed on the data for use in obtaining overall averages 
of the basin snowpack condition. The empirical relation^ 
ships determined were examined for their practical and 
statistical significance as a basis for establishing 
data reliability and coniistency. 

Areal Variability 

The sampling errors and variability of the 
snowpack condition in the drainage basin were determined 
from each group of data, analysed by equations (1) to 
(4). Tables 1 and 2 of Appendix III summarize the results 



* QUIKTIAN System - IBM Digital Computer 

- 21 - 



of the analyses , 

The coefflcleints of variation of depth (Table 1 

of Appendix III) indicated a progressive Increase in 
values from ,209 for the Initial survey, to .957 for 
the survey on February 26, 1969, Similarly, for the 
water equivalent, the coefficient of variation (Table 2 

of Appendix III) ranges fron ,139 to 1,014 for the same 
respeetive time period. 

The extent to which a measure of confidence 
could be placed on the data, with such large variations, 
was determined from equation (5); that is, equation (5) 
gives a measure of the eonfidence limit or Interval 
asaociated with each estimate of the basin average depth 
or water equivalent. For example, applied tO' Table 2 
of Appendix III,,, the confidence interval on the popula- 
tion average water equivalent for' the Initial survey 
pertod, would be given by 2.8 + *043 tg qc Inches and 

for the final survey, would be given by 2.7 + .313 t^ qc 

inches, where tg q^ ^ 1.99 for (N-2) degrees of freedom. 

For the case of the average snow depth (Table 1 of 
Appendix III), the range of confidence interval on the 

population .average would be 12,7 + .6 inches to 7.4 + 

1,8 inches for the initial and final survey period, 

- 22 - 



respectively. A further examination of the results 
showed that the errors associated with the respective 
estimates of the snowpack averages for the basin were 
less than 15 per cent at the 95 per cent confidence 
level for the major snow accumulation period (January 2 
to 15, 1969), 

The general trend of a decrease in accuracy 
of the estimates of the snowpack condition, shown in the 
results, was attributed to the break-up of the pattern 
of distribution of minor snow storms, to the dominant 
effects of wind drifts on exposed accumulations and to 
varying rates and stages of the snow metamorphosis on 
the basin. 

An attempt was made to examine the effect on 
the accuracy pf the estimates of the snowpack condition 
by a 50 per cent reduction in the sampling network. 
Four snow courses, number 1, 2, 6, and 8, with the most 
uniform snow cover were selected from Table 6 of Appendix 
II. A similar statistical analysis, as outlined pre- 
viously (equations (1) to (4)), was carried out for this 
group of data. Tables 3 and 4 of Appendix III show 
the selected results. A cursory examination of the 
results showed that the reduction of the number of snow 
courses (guided by the ranked evaluation) gave an 

- 23 - 



Increase in the values of the estimate of the basin 
average water equivalents and an appreciable reduction 
In areal variation; however, a careful examination of 
the results, as outlined In the previous paragraphs, 
showed that the accuracy of the estimates (within 15 
per cent at the 95 per cent confidence level) was con- 
fined to the same major snow accumulation period. 

Empirical Relationship 

Ihe computation of the average snowpack density 
from a sample of measured depths and water equivalents 
was based on a direct relationship between the two vari- 
ables; that is, an implicitly assumed linear regression 
with the line forced through the origin was utilized 
in the computations . As this implicit relationship was 
accepted for use in computing average snowpack density 
from the data of each snow course, it was extended to 
the computation of the basin snowpack Integrated average 
density, from the combined data from all courses, on a 
particular survey. Subsequently, the knowledge of this 
implicit and accepted relationship was utilized to 
examine and evaluate the reliability of the point measure- 
ments and the quality and reliability of the grouped 
data among the snow courses . If a set of data was 

- 24 - 



reliable and consistent in measurements , the empirical 
relationship derived (equation (6)) would be reliable 
and significant (equations (5) and (7) to (11)) » 

The results of the regression analyses, based 
on equations (6) to (11), carried out on the different 
groups of data, are summarized in Tables 5 and 6 of 
Appendix III. An exaraination of the results (Table 5 
of Appendix III), showed that each coefficient of 

determination was equal to or greater than the accepted 

2 
iralues of r ^ ,25; hence, the regressions were of 

practieal significance. The computer F-values (equation 
(11)) employed for the test of linearity of the regres- 
sions, showed that each F-value was highly slgnlf leant , 
indicating that the variations in the estimated water 
equivalents could be explained nearly entirely by the regres- 
sion. With the appropriate application of equation (5), 
explained on page 11, the confidence limit on the regression 
.coefficients can be detemined; applied to the results 
(Table 5 of Appendix III), the confidence interval on the 
population regression coefficient can be shown to range 
from .21 + ,040 to .33 + .030 from the second to the final 
survey period, respectively. The initial survey gave the 
most sensitive regression coefficient, of value ,07 + ,028, 
These confidence limits gave a measure of the accuracy 

- 25 - 



of the slope of the regression lines. 

From practical knowledge, the origin should 
be a point on the line of regression; however, because 
of errors in measurements, the intercept (equation (6b)) 
may not be equal to zero. The confidence limit on the 
intercept gave a measure of the departure of the regres- 
sion line from the origin. These confidence intervals 
of the intercepts (equation (5)), appropriately applied 
to Table 5 of Appendix III, may be shown to range about 
the origin, with values from .32 + .58 inch on January 15, 
1969, to .19 + .28 inch on March 14, 1969. Alternative- 
ly, the confidence level on the Intercept may be determined 
indirectly from computed t-values; that is, the ratio 

between the respective intercept. A, of a regression 

A 
and its standard error, S^. When t = /§. was computed 

from Table 5 of Appendix III, it was seen that the results 
from only the first and third survey period gave a 
t-value that was respectively greater than tQ qc * 1.99, 

indicating that the Intercepts of the regression from 
the other survey periods were not significant at the 
95 per cent confidence level. In the case of the regres- 
sion coefficients, the corresponding t-value (t - /Sw), 

whan computed from Table 5 of Appendix III, was found to 

- 26 - 



be much greater than t^ «£ = 1.99 for all survey periods, 

indicating, therefore, that the coefficients of regression 
for the respective regressions were in each case very 
significant* 

By operating with the knowledge of the above 
interpretations, regression analyses for the regression 
line forced through the origin, 0(0,0), were carried 
out for the same set of snow data , Table 7 of 
appendix III summarises the results. The regression 
coefficients were measures of the average densities of 
the snowpack. The product of the raspective standard 
error Ej^ and the value of tQ 05 gave a neasure of the 

error associated with each coefficient at the 95 per cent 
confidence level. If appropriately applied, the confidenoe 
interval (equation (5)) on the population regression 
coefficients (Table 7 of Appendix III) gave, for eKample, 
values of .22 + ,032 and ,36 + .046 for the initial and 
final survey period, respectively. Similarly, the t-value, 
when computed for the respective coefficients, was, in 
each case, greater than tQ qj = 1.99; that is, the 

coefficients were all significant. 

Similar regression analyses, as outlined and 
discussed for the total survey data, were performed on 

- 27 - 



the data from the four most uniform snow courses (number 1, 
2, 6, and 8). The results of the analyses are suimnarlzed 
in Tables 6 and 8 of Appendix III, The results followed 
parallel deductions to those of Tables 5 and 7 of 
Appendix III, but showed appreciable increases in the 
ranges of the confidence intervals on the intercepts 
about the origin, with values from ,82 + .98 inch on 
January 27, 1969, to .82 + 1.72 inches on March 14, 1969, 
(equation (5), appropriately applied to Table 6 of 
Appendix III). Similarly, the t -values, when computed. 
Indicated that the value of the intercept was significant 
only for the initial two survey parlods . 

The general Indication was that the regression 
equation (6) of page 8, with the regression line forced 
through the origin, could be applied for the analysis of 
the data, thereby supporting reliability and consistency 
in the point measurements; that Is, based on the validity 
of the implicit relationship between snow depth and water 
equivalent, the compiled data were of acceptable quality 
and accuracy for use in obtaining estimates of the basin 
snowpack water equivalents. It appeared, however, that 
a necessary requirement for practical application of the 
regression 0(0,0) was an appreciable amount of snow 

- 28 - 



accunulaclon, plus a time lapse to allow £or destructive 
and constructive snow metamorphosis (initial settling 
of the pack, loss of shape of the original snow crystals 
and increases in grain size). 



- 29 - 



PRECIPITATION (SNOW) STORAGE ESTIMATES 

The estimation of the winter precipitation 
storage In the snowpack was a necessary procedure for 
obtaining the input Index required for use In the 
hydrologlc calibration of the basin. The direct or 
indirect measurement of the snow water equivalent pro- 
vides for estimating the water stored In the pack at a 
specific time, or for the change in storage between 
time periods* 

An attempt was made to use different methods 
of integrating the individual point measurements of the 
snowpack into basin indices for a quantitative measure 
of depth of water on the basin. The different methods 
were applied mainly for the purpose of comparing the 
estimates determined by weighted average methods to those 
estimates determined by a simple arithmetic procedure. 

Arithmetic Method 

The statistical analysis of snow depth and 
water equivalent data showed that the errors and 
variabilities associated with the averages for the 
basin during the initial periods of snow accimiulatlon 
were acceptable. The snow courses were distributed 

- 30 - 



throughout the range of the basin elevation, thereby 
supporting the expectation of satisfactory Indices of 
basin snowpack condition, if estimated by simple 
aritlnnetic averages . Table 3 of Appendix XV sionmarizes 
the results, showing the precipitation storage in the 
snowpack In terms of estimates of average water 
equivalent or snow depth of given average density, for 
several survey periods during the season. 

All of the measured data from each snow course 
per survey period were included In the computation, 
Including estimates of data from courses with less than 
50 per cent of snow cover. 

Thlessen Method 

The Thlessen method was accepted as applicable 
for estimating the basin snowpack indices, because of 
the assiunptlons with regard to large-scale effects of 
meteorological conditions on the basin and that the 
effects of the local terrain parameters on roinor storm 
distributions and snow cover variability on the basin 
were to be neglected. Outlined on Map 1 of Appendix I 
are the snow course locations and the polygon-area 
distributions. Ihe areas enclosed by each polygon were 

- 31 - 



planimetered on a topographic map of scale 1 inch ■■ I mile. 
The per cent areal distributions from Table 1 of 
Appendix IV were applied to weight the data for the 
respective snow courses to determine estijnates of the 
winter precipitation storage. The results are summarized 
in Table 4 of Appendix IV, in terms of the basin snowpack 
indices for several survey periods , The estimates for 
snow depth were less than the arithmetic average estimates, 
but in general, there were no significant or appreciable 
differences between the estimates of either method. 

Area -Elevation Method 

The snow courses were placed Into zonal areas 
based on 100-foot rises in basin elevation from a lower 
elevation of 600 feet. The area -elevation distribution 
was developed by planimeterlng the areas enclosed by 
each elevation from a basin topographic map of scale 
1 inch > 1 mile. It was assumed that the snow accumula- 
tion in a respective zonal area was approximately equal. 
Table 2 of Appendix III shows the area-elevation and 
zonal area distributions. The zonal area distribution 
factors were applied to weight the average snowpack 
indices on the respective snow course or group of snow 

- 32 - 



courses within the zonal area. Table 5 of Appendix III 
shows a summary of the weighted averages of the basin 
precipitation storage In the snowpack for several survey 
periods , An examination of the results and a comparison 
with the estimates of the previous methods showed that 
there were no significant differences between the 
different estimates . 

Isohyetal Method 

A series of Isohyetal maps were developed for 
the basin snowpack depth for the survey periods, as shown 
in Figures 1 to 6 of Appendix IV. Each map was developed 
Independently from the snow course average values by 
isollne Interpolation. Isohyet interval values used 
were at least twice the standard error of the respective 
average snow depth for the basin. By imposing this limit 
on the isohyet intervals, the interpolation was restricted 
to the same degree of errors associated with the sampling. 
The respective empirical relationship for the regression 
line forced through the origin (for the regression 0(0,0)), 
between depth and water equivalent, with the associated 
standard errors, is shown on each depth isohyetal map 
for the periods of major snowfall (January 2 to 
February 5, 1969). 

- 33 - 



these maps facilitate a qualitative or visual 
Interpretation of areal distribution of snow cover In 
the basin and the changes that occurred between surveys, 
^ch map was analysed for area-lsohyet distribution, 
fhe area enclosed between the Isohyet Intervals was 
planlmetered on a topographic map of scale .5 Inch ■ 
1 mile and used to weight the respective average Isohyet 
value, to determine ultimately the basin Index weighted 
average value. Table 6 of Appendix IV summarizes the 
area-lsohyet distribution of snow depth and the respective 
basin Index. The results show no significant differences 
from the basin Indices derived by the previous methods, 
thereby indicating that the snow courses were adequately 
distributed for use In estimating snow accumulation 
throughout the basin. 



- 34 - 



CONCLUSIONg 

Various observations, analysas and interpre- 
tations of the snow survey data contributed to the follow- 
ing smmiarized conclusions: 

1. A substantial amount of seasonal snow 
accumulation on the basin facllltatad the collection 
of an adequate number of samples for a meaningful 
analysis , 

2. Intra-season freeze and thaw cycles created 
difficulties in obtaining ideal core samples, thereby 
reducing the desirable accuracy of point measurements. 

I. Evaluation of the data by statistical analysis 
facilitated the identification of the snow courses with 
poor or doubtful measurements . More uniform distribu- 
tion of snow cover and acceptable representation were 
achieved from five snow course locations (snow courses 
number 1, 2, 5, 6, and 8). 

4. The major period of snow accumulation provided 
adequate data for the determination of estimates of 
winter precipitation amounts for a degree of accuracy 
within 15 per cent at the 95 per cent confidence level. 

3 . The quality of the data was ascertained 
through a simple linear regression, which verified that 

- 35 - 



practical estimates of the snowpack water equivalent 
could be derived from the measured snow depth of a 
given average density. Although the computed regres- 
sions were good prediction equations, they were, however, 
specific to the basin snowpack conditions of the winter 
season of 1968-1969. 

6. Reliable estimates of indices of the basin 
snowpack condition could be derived from a 50 per cent 
reduction in the evaluated sampling network. 

ft. Determination of estimates of the precipi- 
tation storage in the basin snowpack, for specific time 
periods, by several methods, showed no significant 
difference between the respective estimates . This in- 
dicated that the areal distribution of the snow courses 
throughout the basin was adequate and that their evaluation 
was limited mainly by the quality of the data. The 
arithmetic averages were desirable for easy computation 
of large volumes of data. The area-elevation and 
isohyetal method estimates were desirable for quantitative 
interpretation of the snow cover areal distribution and 
for the comparison of changes in the areal snow cover and 
snowpack conditions between certain time intervals , 

8. The pattern of the basin snow cover distribu- 
tion and time trends in acciunulation and depletion 

- 36 - 



showed that the snowpack depth and water equivalent 
increased with increased basin elevation. Major snow 
stoms tended to be more unifom and proportionally 
distributed on the basin. On the other hand, minor 
snow storm distributions were affected by local terrain 
parameters, thereby Increasing the areal variability 
of snow cover on the basin. 



- 3? - 



RECOMMENDATIONS 

1. The existing density of the sampling network 
should be maintained in order to ensure that the degree 
of represent iveness of snow cover evaluated is sufficient- 
ly reproducible over a number of seasons . 

2. Due to the poor quality of the data obtained 
from snow course nimiber 4, an alternative location 
should be Investigated. 

3. Upon establishing an acceptable degree of 
reproducibility in the snow cover on the basin from the 
existing network, a sampling network of at least five 
snow courses should be maintained. A minimimi of ten 
sampling points per course should be maintained In order 
to ensure representative statistical samples. 

4. The frequency of the snow survey period should 
be increased to once per week during the period of 
significant freeze-thaw cycles. 



- 38 - 



BIBLIOGRAPHY 



1. Adanis, W. and Roger son, R. - 1968 

"Snowfall and Snowcover at Knob Lake, Central 
Labrador, Ungava.", Proceedings of the 25th 
Annual Meeting of the Eastern Snow Confer encejp 
pp. 110-139. 



2, Beaumont, R, and Work, R. - 1963 

"Snow Sampling Results with Differing Snow 
Samplers", Proceedings of the 20th Annual 
Meeting of the Eastern Snow Conference, pp. 185-191 



Canada Department of Transport, 
Meteorological Branch 

- 1961 - "A Guide to the Selection of Snow 

Survey Courses", Cl-r . 3566, OBS-305 . 

* 1961 - "The Mount Rose Sampler", Cir. 3572, 
INS. -105. 

«• 1964 - "Instruction to Snow Surveyors", Cir* 
4113, OBS-329. 



4. Chow, V.T. - 1964 

"Handbook of Hydrology", McGraw-Hill Book Co, 
Inc . , New York . 



U, S, Army Corps of Engineers - 1959 

"Snow Hydrology", OTS-U.S. Department of Commerce, 
PB. 151-660. 



6. Fisher, R. - 1958 

"Statistical Methods for Research Workers", 
Hafner Publishing Co. Inc., New York. 



- 39 - 



?, Llfisley, R. et al, - 1949 

"Applied Hydrology", McGraw-Hill Book Co. Inc., 
New York. 



8. Mode, E. - 1961 

"Elements of Statistics", Prentice-Hall Inc., 
New Jersey. 



Nicholas, L, - 1963 

"Snow Survey Record", Proceedings of the 20th 
Annual Meeting of the Eastern Snow Conference, 
pp. 198-209. 



10. Puccini, D. - 1967 

"Snow Survey Report - Wllmot Creek Basin", 1966' 
1967, OWRC Preliminary Data Report No. 67-1. 



11. Snedecor, G, and Cochran, W. - 1968 

"Statistical Methods", Iowa State University, 
Press, Iowa, 



12. Thorn, H, - 1966 

"Some Methods of Climatological Analysis", 
WMO-No. 199, TP, 103, Technical Note No. 81 



13. Wilson, J. - 1966 

"Determination and Uses of Best Individual 
Sampling Points On Individual Snow Courses", 
Proceedings on the 34th Annual Meeting of the 
Wee tern Snow Conference, pp. 82-86. 



- 40 - 



14. Secratarlat of the Canadian National 

Coimilttee for IHD - 1966 

"Guidelines for Research Basin Studies," 
ProGeedlngs of the 14ational Workshop 
Seminar on Research Basin Studies, 
Canadian National Conraittee for IHD, 



• 41 - 



APPENDICES -DATA SUhOlARIES AND 



RESULTS OF ANALYSES 



- 42 - 



Appendix I 

Page 

Map 1 

Snow Course Locatloni M 

Figures 1 to 8 

Diagrammatic Sketches of Snow 45 " 

Course Layout: OSC-1 to 8 52 

Table 1 

River Baslii Research Branch ^ 

Snow Survey Report 

Table 2 

Summary of Snow Survey Data Si, 



- 43 - 



/ 






-/ 



r^ 



/\ 



\1* : -^^^ 









ONTARIO WATER RESOURCES COMMISSION 
DIVISION OF AA7ER RESOURCES 



INTERNATIONAL HYDROLOGICAL DECADE 

EAST AND MIDDLE OAKVILLE CREEKS 
DRAINAGE BASIN 



SCALE 1:100,000 

C 1 
H ' r-l l-J N I-. ! 1 



^^ ^^ Sub basin boundary jk Snow course 

Drainage basin . PoNgon {Thiessen) a Strsamftow gauging 

' " boundary boundan' ^ stalion 




Map 1. Snow course loeations. 




,25 mile to Federal gauge 



Township! Oakville 
Concesalon: VI 
Lot- 1 



n.t.s , 



FiRure 1 

Diagrammatic Sketch of Snow Course Layout: OSC-1 



SC - Snow Course 
n.t.s. ^ not to scale 



- 45 - 



Township: 


Oakville 


Concession: 


IX 


Lot: 


3 




Figure 2 

Dlagrmranatic Sketch of Snow Course Layout: OSC-2 



- 46 - 




Township: Oakville 
Concession: VII 
Lot: 13 



n.t: .s 



Figure 3 

Diagrammatic Sketch of Snow Course Layout: OSC-3 



- 47 - 




Township: Esqueslng 
Concession: V 
Lot: 6 



n.t .s 



Figure 4 

Diagrammatic Sketch of Snow Course Layout: OSC-4 



- 48 - 




Tovmship; Esqueslng 
Concession: X 
Lot? 5 



n.t ,s , 



Figure 5 

Diagrammatic Sketch of Snow Course Layout; OSC-5 



- 49 - 




n.t .s 



Figure 6 

Diagrammatic Sketch of Snow Course Layout: OSC-6 



- 50 - 



Orchard 




ti 



Township* Esqueslng 
Concession: VI 
Lot: IS 



Figure 7 

Diagrammatic Sketch of Snow Course Layout: OSC-7 



- 51 - 




Township: Esqueslng 
Concession: V 
Lot: 20 



Figure 8 

Diagrammatic Sketch of . Snow Course Layout: OSC-8 



- 52 - 



Table 1 

HIVER BASIN RESEARCH BRANCH 
SNOW SURVEY REPORT 

Basin : Oakville Creek S tat 1 on : OSC-8 



Date : February 5> 1969 Time : 3 : 00 - 3r30 Temp ;^ 17^ 

QbBerver; A. Sweetman & M. Long 



1. 

Sample 
Number 


2. 
Snow 
Depth 


3. 
Length 
of Core 


4. 
Weight 
of tube 


5. 

Weight of 

tube & snow 


6. 

Water 

Equivalent 


7. 
Density 


1 


14.7 


12.7 


4.3 


8.3 


4.0 


.27 


2 


16.5 


14.0 


4.3 


9.4 


5.1 


.31 


3 


14,0 


11.0 


4.3 


7.7 


3.4 


.24 


k 


12.0 


9.6 


4.3 


6.6 


2.3 


.19 


5 


16.1 


14.4 


4.3 


8 .7 


4.4 


.27 


6 


19.3 


15.3 


4.3 


8.3 


4.0 


.21 


7 


17.8 


14.8 


4.3 


8.6 


4.3 


.24 


8 


17.8 


17.8 


4.3 


10.3 


6.0 


,34 


9 


20.5 


14.7 


4,3 


9.3 


5.0 


.24 


10 


21.0 


15 .0 


4.3 


8.5 


4.2 


.20 


TOTAL 


169.7 


139.3 


43.0 


85.7 


42.7 


2.51 


MEAN , 


17.0 


13.9 


4.3 


8.6 


4.3 


.25 



Crust : 



hard 



Soil Conditions: frozen 



Ice Layers 



COMfffiNTS 



- snow is on grass layer 



- TiiiiPd.MSC Type -I sampler. 



- 53 - 



Table 2 



Summary of Snow Survey Data 









Water 




Snow 




Snow Depth 


Equtvalent 




Course 


Date 


(inches) 


Cinches ) 


Density 


OSC-1 


2-1-69 


12.6 


1*1 


.22 




15-1-69 


11.1 


S Ji>-S 


.25 




27-1-69 


4.9 


IJ 


.31 




5-2-69 


3.9 


0.4 


.11 




26-2-69 


- 


0.1 e 


- 




14-3-69 


0.0 


0.0 


0.00 




24-3-69 


0.0 


0.0 


0.00 


OSC-2 


2-1-69 


12.2 


2.5 


.20 




15-1-69 


17.3 


3.9 


.23 




27-1-69 


9.1 


3.2 


.35 




5-2-69 


10.4 


2.7 


.26 




26-2-69 


5.5 


1,5 


.26 




14-3-69 


0,9 


0.3 


.34 




24-3-69 


0.0 


0.0 


0.00 


OSC-3 


2-1-69 


11.5 


2.5 


.22 




15-1-69 


10.4 


2.2 


.21 




27-1-69 


5.3 


1.6 


.31 




5-2-69 


4.9 


1.0 


.20 




26-2-69 


1*7 


0,4 


.23 




14.3-69 


m 


0.2 e 


- 




24-3-69 


0.0 


0.0 


0.00 


OiC-4 


2-1-69 


11.9 


2,9 


.25 




15-1-69 


14.5 


3.8 


.26 




27-1-69 


6.7 


2.4 


.35 




5-2-69 


5.5 


1.8 


.26 




26-2-69 


3.1 


0.9 


.17 




14-3-69 


3.7 


1.4 


.37 




24-3-69 


0.0 


0.0 


0.00 



- 54 - 



Table 2 (cont'd) 









Water 




Snow 




Snow Depth 


Eqiilvalent 




Course 


Date 


(Inches ) 


(Inches) 


Density 


OSC-5 


2-1-69 


10.8 


2.7 


.25 




15-1-69 


12.7 


3.0 


.23 




27-1-69 


7.0 


2.1 


.30 




5-2-69 


5.1 


1.4 


.27 




26-2-69 


2.0 


0.4 


.18 




14-3-69 


0.8 


0.2 


.19 




24-3-69 


0.0 


0.0 


0.00 


OSC-6 


2-1-69 


11,0 


2.8 


.26 




15-1-69 


15.3 


4.3 


.28 




28-1-69 


9.8 


3.4 


.34 




5-2-69 


9.6 


3,4 


.35 




26-2-69 


i.4 


2.0 


.31 




14-3-69 


7.5 


3.1 


.42 




24-3-69 


0.0 


0.0 


0.00 


OSC-7 


2-1-69 


13.8 


2.9 


,U 




15-1-69 


13.0 


2.8 


.21 




28-1-69 


8.9 


2.2 


.26 




5-2-69 


7.2 


1.4 


.20 




26-2-69 


4.6 


1.0 


,21 




14-3-69 


3.5 


1.3 


.38 




24-3-69 


0.0 


0.0 


0.00 


OSC-8 


2-1-69 


18.2 


3.0 


.17 




15-1-69 


20.^ 


3.9 


.20 




28-1-69 


13.9 


3.3 


.24 




5-2-69 


17.0 


4.3 


.25 




26-2-69 


16.4 


4.1 


.26 




14-3-69 


14.9 


4.9 


.33 




24-3-69 


0*0 


0.0 


0.00 



e - estimated 



- 55 - 



Appendix II 

Page 

Table 1 

Average, Standard Deviation and Coeffl- Jf 

clent of Variation of Snowpack Depth by Snow 
Courses for the Period of Snow Accumulation 

Table 2 

Average, Standard Deviation and Coeffl- |9 

clent of Variation of Snowpack Water Equivalent 
by Snow Courses for the Period of Snow Accumu- 
lation 

Table 3 

Average, Standard Deviation and Coefficient #E 
of Variation of Snowpack Core Length By Snow 
Courses for the Period of Snow Accumulation 

Table 4 

Average, Standard Deviation and Coefficient 63 
of Variation of Snowpack Density by Snow 
Courses for the Period of Snow Accumulation 

Table 5 

Ranked Snow Courses by Coefficient of ii 

Variation, C^, of Snowpack Depth for the 

Period of Snow Accumulation 

Table 6 

Summary of Ranked (Multiple) Snow Courses by 66 
Coefficient of Variations of Snowpack Depth, 
Water Equivalent, Core Length and Density 
for the Period of Snow Accumulation 



- 56 - 



Table 1 

Average I Standard Deviation and 
Coefficient of Variation of Snoi^pack Depth By 
Snow Courses for the Period of Snow Ac cumulation 







Average 


Standard 


Cbef fie lent 


Survey 


Snow 


Depth. 


Deviation 


of 


Period 
(Date) 


Course 
(OSC- ) 

1 


mm. 

(In.) 
12.6 


Sd 

(in.) 
1.35 


Variation 


2.1.69 


.108 




2 


12.2 


1.82 


.149 




3 


11.5 


.81 


.071 




4 


11.9 


2.57 


.216 




5 


10.8 


.70 


.065 




6 


11.0 


1.14 


.103 




7 


13.8 


1.02 


.074 




8 


18.2 


1.74 


.096 


15,1.69 


1 


11.1 


1.45 


.131 




1 


17.3 


2.67 


.152 




I 


10.4 


2.17 


.209 




* 


14.5 


4.34 


.300 




i 


12,7 


1.84 


,145 




i 


15.3 


2.68 


.175 




f 


13.0 


3.05 


.234 




:i 


20.5 


3.22 


.158 


27.1.69 


1 


4.9 


1,67 


.341 




i 


9.1 


1.81 


.199 




I 


5,3 


1.41 


.276 




i 


6.7 


2.62 


.392 




i 


7.D 


1.81 


.259 




• 


9.8 


2.21 


.226 




r 


8.9 


1.69 


.190 




M 


13.9 


1.14 


.082 



- 57 - 



Table 1 (cont'd) 







Average 


Standard 


Coefficient 


Survey 


Snow 


Depth, 


Deviation, 


of 


Period 


Course 


D. 


Sj), 


Variation, 


(Date) 


(OSC- ) 
1 


(in.) 
3.9 


(in.) 


% 


5.2.69 


1.11 


.285 




2 


10.4 


2,45 


.236 




i 


4.9 


1.86 


.380 




i- 


53 


4.15 


.755 






sa 


2.23 


.436 




i 


^,6 


2.29 


.237 




f 


7.2 


2.96 


.413 




ft 


17.0 


2.89 


.169 



- 58 - 



Table 2 

Average, Standard Deviation and 
Coefficient of Variation of Snowpack Water Equivalent 
By Snow Courses for the Period of Snow Accumulation 







Average 


^^ , , Coeffieient 
Standard ^^ 


Survey 
Period 


Snow 
Course 


Water 
Equivalent 


Deviation variation 
% r 


(Date) 


(OSC- ) 
1 


W (in.) 
2.7 


(in.) 


W 


2.1.69 


.13 


,048 




2 


2,5 


.36 


.144 




1 


2.S 


.29 


.116 




4 


2.9 


,51 


.175 




1 


2.7 


.37 


.137 




1 « 


2.8 


.27 


.097 




1 


2.9 


.41 


,141 




i 


3.0 


.38 


.127 


15.1,69 


1 


2.8 


.49 


.175 




2 


3.9 


,BB 


.225 




3 


2.2 


.62 


,282 




4 


3.8 


1.54 


.405 




5 


3.0 


.68 


.227 




6 


4.3 


.81 


.188 




7 


2,8 


.76 


.271 




a 


3.9 


1.14 


.292 


27.1.69 


1 


1.6 


.61 


.381 




2 


3.2 


.76 


.237 




A 


1.6 


.59 


.369 




4 


2.4 


1.19 


.495 




1 


2,1 


.82 


.390 




i 


3.4 


1.20 


.354 




f 


2,2 


.67 


.305 




• 


3.3 


.87 


.263 



* 59 - 



Table 2 (cont'd) 







Average 
Water 


Standard 


Coefficient 


Survey 


Snow 


Deviation 


of 


Period 


Course 


Equivalent 


% 


Variation 


(Date) 


(OSC- ) 


W (in,) 


(in.) 


% 


5.2.69 


1 


.4 


.14 


.350 




1 


2.7 


1.14 


.415 




i 


1.0 


.50 


.500 




# 


1.8 


1.32 


,745 




1 


3.4 


.79 


.565 




1 


3.4 


.96 


,283 




t 


1.4 


.87 


.620 




i 


4.3 


l.Ol 


.236 



- 60 - 



Table 3 

Average p Standard Deviation and 
Coefficient of Variation of Snowpack Core Length 
By Snow Courses for the Period of Snow Aceumiilatlon 











Coefficient 


Survey 


Snow 


Average 


Standard 
Deviation 
\ (in.) 


of 


Period 


Course 


Core Length 


Variation 


(Date) 


(OSC- ) 
1 


L (in.) 
8.9 


Cl 


2.1.69 


.078 




2 


8.8 


1.23 


.140 




J 


7.6 


.97 


.128 




♦ 


8.8 


2.47 


.281 




s 


8.3 


1.08 


.130 




i . 


9.3 


1.16 


.125 




t 


9.8 


1.83 


.187 




i 


10.3 


1.66 


.161 


15.1.69 


1 


9.7 


1.51 


.156 




t 


14.1 


3.01 


.214 




i 


7.5 


2.48 


.331 




4 


12.9 


5.30 


.411 




1 


11.0 


1.92 


.175 




i 


14.1 


2.45 


.174 




1 


10.2 


2.74 


.268 




i 


14.4 


3.54 


.246 


27.1.69 


1 


4.4 


1.29 


.294 




1 


8.3 


1.76 


.213 




1 


4,6 . 


.89 


.194 




# 


6.1 


2.62 


.430 


'f 


■ s 


6.6 


1.81 


.275 




i 


9.4 


2.21 


.236 




f 


7 .4 


1.32 


.178 




i 


9.7 


2.81 


.290 



- 61 - 



Table 3 (cont'd) 











Coefficient 


Survey 


Snow 


Average 


Standard 


of 


Period 


Course 


Core Length 


Deviation 


Variation 


(Date) 


(OSC- ) 
1 


L (in.) 
3.7 


Sl (in.) 
.92 


Cl 


5.1.69 


.248 




2 


9.4 


2.36 


.252 




3 


4.5 


1.62 


.360 




4 


5.2 


3.90 


.750 




5 


4.9 


2.13 


.435 




6 


9.2 


2.44 


.265 




7 


6.2 


2.04 


.329 


* 


8 


13.9 


2.32 


.169 



- 62 - 



Table 4 

Average j Standard Deviation and Coefficient 
of Variation of Snowpack Density 
by Snow Courses for the Period of Snow Accumulation 



Survey 
Period 


Snow 
Course 


Average 
Denis ty 


Standard 
Deviation 


Coefficient 
of Variation 


(Date) 


(OSC- ) 
1 


d (in.) 
.22 


Sd (in.) 
.022 


Cd 


2.1.69 


.100 




2 


.20 


,017 


.085 




3 


.22 


.020 


.091 




4 


.25 


.014 


.056 




S 


.25 


.030 


.120 




6 


.26 


.014 


.054 




7 


.21 


.028 


.134 




8 


.17 


.026 


.153 


15.1.69 


1 


.25 


.037 


.148 




2 


.23 


.032 


.139 




3 


.21 


.035 


.167 


». 


4 


.26 


.036 


,138 




5 


.23 


.030 


,131 




6 


.28 


.014 


.050 




7 


.21 


.014 


.067 




8 


.20 


.056 


.280 


27.1.69 


1 


.31 


.047 


.151 




a 


.35 


.056 


.160 




t 


,31 


.063 


.204 




A 


.35 


.041 


.117 




5 


.30 


.046 


.153 




6 


.34 


.057 


.168 




7 


.26 


.096 


.370 




-i 


.24 


.061 


.254 



- 63 - 



Table 4 (cont'd) 



Survey 


Snow 




Average 


Standard 


Coefficient 


Period 


Coursi 


e 


Density 


Deviation 


of Variatioii 


(Date) 


(OSC- 
1 


A 


L 


(111.) 
.12 


Sd '" ^ 


(in.) 
.098 


Cd 


5.2.69 


.815 




2 






.27 




.081 


.300 




1 






.20 




.039 


.195 




4 






.26 




.119 


.457 




i 






.27 




.094 


.347 










.35 




.059 


.169 




f 






.20 




.064 


.320 




* 






•25 




.023 


.092 



•- 64 - 



Table 5 
Ranked Snow Courses by Coefficient of 
Variation, Cj^, of Snowpack Depth for the Period 

of Snow Accumulation 














ACCUMULATION PERIOD 
- STATISTICAL PARAMETERS 


. 






DATE 


2.1J 


S9 


15.1 


.69 


27.1.69 


5.2 


.69 


Total 


Group 


Snow 


















Course 


r 


Rank 


c 


Rank 


r 


Rank 


c 


Rank 


Rank 


Rank 


OSC- 


% 


Oc) 


^D 


(k) 


% 


(k) 


% 


(k) 


(Xk) 


(K) 


1 


.108 


6 


.131 


1 


.341 


7 


.285 


4 


18 


5% 


2 


.149 


7 


.152 


3 


.199 


3 


.236 


2 


15 


2h 


3 


.071 


2 


.209 


6 


.276 


6 


.380 


5 


19 


7 


4 


.216 


8 


.300 


8 


.392 


8 


.755 


8 


32 


8 


5 


.065 


1 


.145 


2 


.259 


5 


,436 


7 


15 


2h 


6 


-103 


5 


.175 


5 


.226 


4 


.237 


3 


17 


4 


7 


.074 


3 


.234 


7 


.190 


2 


.413 


6 


18 


5h 


8 


.096 


4 


,158 


4 


.082 


1 


.169 


1 


10 


1 



Table 6 
Summary of Ranked (Multiple) Snow Courses by 
Coefficient of Variations of Snowpack Depth, Water Sjuivalent, 
Core Length and Density for the Period of Snow Accumulation 



'9i 



Snow 

Course 

OSC- 




GROUP RANK K 








Total 
Group 
Rank 
(IK) 


Multiple 
Rank 
(R) 


Depth 


Water 
Equivalent 


Core Length 


Density 


Ik 


K 


Tk 


K 


Ik 


K 


Ik 


K 


1 


18 


5% 


11 


2 


11 


1 


21 


6 


14% 


3 


2 


15 


2% 


15 


4 


15 


3 


16 


3 


12% 


2 


3 


19 


7 


19 


5 


18 


4% 


20 


5 


21% 


6 


4 


32 


8 


32 


8 


32 


8 


14 


2 


26 


8 


5 


15 


2% 


22 


7 


19 


eh 


18 


4 


20 


5 


6 


17 


4 


10 


1 


12 


2 


9 


1 


8 


1 


7 


18 


5% 


21 


6 


19 


6% 


22 


7 


25 


7 


8 


10 


1 


14 


3 


18 


4^ 


24 


8 


16% 


4 



Appendix III 



Table 1 



Table 2 



Table 3 



Table 4 



Table 5 



Page 



Standard Deviations and Variations 69 

of Basin Snowpack Measured Depths by 
Survey Periods 



Standard Deviations and Variations 70 

of Basin Snowpack Measured Water 
Equivalents by Survey Periods 



Standard Deviations and Variations of 71 
Basin Snowpack Measured Depths for the 
Most Uniform Snow Courses (OSC-1, 2, 6 
and 8) by Survey Periods 



Standard Deviations and Variations of 72 
Basin Snowpack Measured Water Equi- 
valents for the Most Uniform Snow 
Courses (OSC-1, 2, 6 and 8) by Survey 
Periods 



Statistical Association of Basin Snow- 73 
pack Measured Depths and Water 
Equivalents by Survey Periods 



- 67 - 



Page 

Table 6 

Statistical Association of Basin Snow- fi 
pack Measured Depths and Water Equi- 
valents for the Most Unlfom Snow Courses 
(OSC-1, 2, 6 and 8) by Survey Periods 

Table 7 

Statistical Association of Basin Snow- f| 
pack Measured Depths and Mater Equi- 
valents by Survey Periods for the 
Regression 0(0,0) - (Wc = bD) 

Table S 

Statistical Association of Basin Snow- fi 
pack Measured Depths and Water Equi- 
valents for the Most Unifomi Snow 
Courses (OSC-1, 2-6, and 8) by Survey 
Periods for Regression 0(0,0) 

(W = bD) 
c 



- 68 - 



Table 1 

Standard Deviations and Variations of 
Basin Snowpack Measured Depths by Survey Periods 

Standard 



Survey 
Period 
(Date) 


Average 
Depth, 
B (in.) 

12.7 


Standard 
Deviation, 
Sd (in.) 

2.64 


Error of 
Average 
Depth, 
$5 (in.) 

.295 


Coeffi- 
cient of 
Variation, 


2.1.69 


.209 


15.1.69 


14.4 




4.13 


Ml 


.288 


27.1.69 


8.1 




3.29 


.368 


.404 


5.2.69 


8.0 




4.77 


.533 


.599 


3*26.2.69 


5.7 




5.43 


.650 


.957 


*14.3.69 


7.4 




5.71 


.903 


,774 



/ OSC-1 excluded ) 

) or^c: 50% snow cover 
* OSC-1, 2, 3, and 5 excluded ) 



- 69 - 



Table 2 

Standard Deviations and Variations of 

Basin Snowpack Measured Water Equivalents 

by Survey Periods 



Survey 
Period 
(Date) 


Average 
Water Equi- 
valent , 
W (in.) 


2.1.69 


2.8 


15.1.69 


3.3 


27.1.69 


2.5 


5.2.69 


2.1 


#26.2.69 


1.5 


*14.3,69 


2.7 



Standard 
Deviation, 
Sw (in.) 


Standard 
Error of 
Average 
Water 

Equivalent, 
Sw (in.) 

.043 


Coeffi- 
cient of 
Variation 

Cw 


m' 


.139 


1.12 


.125 


.335 


1.08 


.121 


.434 


1.51 


.169 


.735 


1.49 


.178 


1.014 


1.98 


.313 


.745 



J* OSC-1 excluded ) 

) or <r 501 snow cover 
* OSC-1, 2, 3 and 5 excluded) 



- 70 - 



Table 3 

Standard Davlatldns and Variations of 

Basin Snowpack Measured Depths for the Most Uniform 

Snow Courses (OSC-1, 2, 6 and 8) by Survey Periods 

Standard 



Survey 
Period 
(Date) 


Average 
Depth 
B (in.) 

13,4 


Standard 
Deviation, 
S^ (in.) 

3.13 


Error of 
Average 
Depth, 
S]5 (in.) 

.494 


Coeffi- 
cient of 
Variation 

^D 


^ 2.1.69 


.234 


15.1.69 


16,0 


4.25 


.672 


.265 


27.1.69 


9.3 


3.74 


.591 


.400 


5.2.69 


10.2 


5.18 


.818 


.505 


?t26.2.69 


9.4 


5.76 


1,052 


,610 


*14.3.69 


11,2 


4.52 


1.009 


.404 



f OSC-1 eiccluded ) 

) or < 50% snow cover 
* OSC-1 and 2 excluded ) 



- 71 - 



Table 4 

Standard Deviations and Variations of 
Basin Snoi^ack Measured Water Equivalents for the 
Most Uniform Snow Courses (OSC-1, 2, 6 and 8) by 
Survey Periods 



Survey 
Period 
(Date) 


Average 
Water 
Equivalent 
W (In.) 


2.1.69 


2.8 


15.1.69 


3.7 


27.1.69 


2,9 


5.2.69 


2.7 


3*26.2.69 


2.6 


•14.3.69 


4.0 





Standard 






Error of 






Average 


Coeffi- 


Standard 


Water Equi- 


cient of 


Deviation, 


valent , 


Variation 


Sy (in.) 


.055 


Cy 


.35 


.126 


1.00 


.156 


.268 


1.14 


.181 


.400 


1.67 


.265 


.620 


1.51 


.276 


.589 


1.42 


.316 


.358 



•ff OSC-1 excluded ) 

) or 
* OSC-1 and 2 excluded) , 



50% snow cover 



- 72 - 



Table 5 

Statistical Association of Basin Snowpack Measured 
Depths and Water Equivalents by Survey Periods 



l4 



Survey 
Period 
(Date) 


Average 
Water 
Equi- 
valent 
W (in.) 


Intercept 
A (in.) 


Regres- 
sion 
Coeffi- 
cient, b 


STANDARD ERROR OF 


1 

Coeffi- 
cient of 
Determina- 
tion 
r2 


F-Value 


Estimate 
Se (in.) 


Intercept 
Sa (In,) 


Regres - 
sion 
Coeffi- 
cient 

Sb 


2.1.69 


2.8 


1.81 


.07 


.330 


.li3 


.014 


.25 


27.9 


15.1.69 


3.3 


.31 


.21 


Jll 


.290 


.019 


.58 


117.8 


2?. 1.69 


2.5 


.46 


.25 


.707 


.212 


.024 


.57 


105.2 


5.2,69 


2.1 


-,lf 


.28 


.686 


.150 


.016 


.79 


306.2 


?t26.2.69 


1.5 


M 


.26 


.518 


.090 


.012 


.88 


503.4 


*14.3.69 


2.7 


M 


.33 


.534 


.139 


.015 


.93 


496.8 



# OSC-1 excluded | 

) or < 50% snow cover 

* OSC-1, 2, 3 and 5 excluded ) 



* 



Table 6 

Statistical Association of Basin Snowpack 
Measured Depths and Water Equivalents for the 
Most Ifeiform Snow Courses (OSC-1, 2, 6 and 8) by Survey Periods 






: 


Average 
Water 


; 


Regres- 


STANDARD ERROR OF 


1 

Coeffi- 






.: 


Regres- 
sion 


Survey 
Period 
(Date) 


Equi- 
valent 
W (in.) 


Intercept 
A (in.) 


sion 
Coeffi- 
cient, b 


Estimate 
Se (in.) 


Intercept 
Sa (in.) 


Coeffi- 
cient 

Sb 


cient of 
Determina- 
tion, r^ 


F-Value 


2.1.69 


2.8 


2.02 


.06 


.306 


.245 


.016 


.23 


12.4 


15.1.69 


3.7 


1.46 


.14 


.812 


.626 


.031 


.34 


21.4 


27.1.69 


2.9 


.82 


.22 


.810 


.492 


,035 


.50 


40.0 


5.2.69 


2.7 


-.19 


.28 


.830 


.594 


.026 


.76 


121.7 


A26.2.69 


2.5 


.36 


.23 


.705 


.536 


.023 


.78 


104.9 


*14.3.69 


3.9 


.82 


.28 


.651 


,863 


.033 


.79 


71.7 



f OSC-1 excluded ) 

) or < 50% snow cover 
* OSC-1 and 2 excluded ) 



Table 7 

Statlitleal Association of 
Basin Snowpack Measured Depths and Water Iquivalents 
by Survey Periods for the Regression 0(0,0) 



Survey 
Period 
(Date) 


Average 
Water 
Equivalent 
^ (in.) 


2.1.69 


2.8 


15.1.69 


3.3 


27.1.69 


2.5 


5.2.69 


2.1 


#26.2.69 


1.5 


*14.3.69 


2.7 



(W - bD) 
c 


-J 




Regression 
Coefficient, 
b 


Standard 
Error of 
Estimate, 
Sg (in.) 

.497 


Standard 
Error of 
Reg, Coef. 

^b 


.22 


.016 


.23 


.717 


.021 


.31 


.728 


. .029 


.27 


.693 


.028 


.26 


.519 


.024 


.36 


.547 


.023 



# OSC-1 excluded ) 

) or < 50% snow cover 

* OSC-1, 2, 3 and 5 excluded ) 



- 75 - 



Table 8 

Statistical Association of 

Basin Snowpack Measured Depths and Water Equivalents 

for the Most Oniform Snow Courses 

(OSC-1, 2, 6 & 8) by 

Survey Periods for Regression 0(0»0) 

(% - bD) 



Average Standard Standard 

Survey Water Regression f ^J'^ ^^ f ^^^,°^ 

Period Equivalent Coefficient ftl^f ^e Reg. Coef 

(Date) W (in.) b ^e ^^"'-^ ^b 



2.1.69 2,8 .21 ,558 .023 

15.1.69 3,7 .23 .897 .035 

27.1.69 2,9 .31 .867 .045 

5.2.69 2*7 .27 .836 .042 

#26.2.69 2.6 .28 .731 .038 

*14.3.69 4.0 ,35 .725 .035 



# OSC-1 excluded ) 

) or <• 5 OX snow cover 

* OSC-1, 2, 3 and 5 excluded) 



" 76 -^ 



Appendix IV 



Table 1 



Area! Distribution of Snow Courses 
(Thies s en ' s Method ) 



Page 



78 



Table 2 



Area- Elevation and Zonal-Area 
Bistribution of Snow Courses 



79 



Table $ 



Arithiietic Averages of Basin Snow- 
pack Indices by Survey Periods 



81 



Table 4 



Weighted Averages (by Thiessen's Method) 
of Basin Snowpack Indices by Survey Periods 



82 



Table 5 



Weighted Averages (by Area -Elevation Method) 
of Basin Snowpack Indices by Survey Periods 



83 



fable 6 



Area-Isohyet Distribution and Basin Weighted 
Average Snowjpack Depth by Survey Feriods 



84 



Figures 1 to 6 

Isohyets of Snowpack Depth in Inches 
(Survey Periods: 2.1.69 to 14.3.69) 



m - m 



- 77 - 



Table 1 

Areal Distribution of 
Snow Courses (l^iessen's Method) 



Snow 

Course 

OSC- 


Site 

Elevation 
- Feet 
(a.s.l.) 


i Sub- Basin 

2 
Drainage Area in Mi 


Areal 
Cover - 
. age 

(Mi^) 


Percent 
Areal 
Cover- 
age 
(%) 


0-1 


0-2 


0-3 


0-4 


1 


600 


- 




.66 


- 


6.62 


8.8 


2 


625 


- 


- 


.02 


.19 


7.06 


9.4 


3 


625 


- 


- 


10.97 


3.76 


18.99 


25.2 


4 


725 


2.67 


4.85 


14.78 


- 


14.78 


19.5 


5 


775 


- 


- 


1.65 


3.06 


6.88 


9.1 


6 


800 


- 


- 


3.66 


2.33 


5.99 


7.9 


7 


850 


6,26 


6.26 


8.91 


- 


8.91 


11.8 


8 


1,000 


6.29 


6.29 


6.29 


- 


6.29 


8.3 


Total 
Area 
















mn 




15.22 


17.40 


46.94 


9.34 


75.52 


100.0 


Percent 
Area (X) 




20.2 


23.0 


62.0 


12.3 


100.00 





Mi - square miles 
a.s.l. > above sea level 



- 78 - 



Table 2 

Area- Elevation and Zpnal-Area 
Dlstrlbucion of Snow Courses 





Area Below 


Area 


Zonal 






Elevation 


Enclosed 


Area 


Snow Course & 


Elevation - 


2 


2 


2 


Distribution 


Feet (a.s.l.) 


(Mi ) 


(Ml ) 


(Mi ) 


Factor 






1.05 






600 


1.05 


8.91 






625 


9.96 


12.85 




(OSC-1, 2 & 3) 


650 


22.81 












7.66 






675 


30.47 


5.06 






700 


36.53 




36.53 


.484 






7.32 






725 


43.85 


1.65 




(OSC-4, 5 & 6) 


750 


45.50 












8.65 






800 


54.15 




17.62 


.233 






8.78 






850 


62 .93 


37 




(OSC-7) 


900 


63.90 




9.75 


.129 













- 79 - 



Table 2 (cont'd) 



Elevation - 


Area Below 

Elevation 
2 


Area 
Enclosed 
2 


Zonal 

Area 
2 


Snow Cburse & 
Distribution 


Feet (a.s.l.) 


(Mi ) 


(Ml ) 


(Mi ) 


Factor 




! 


1.25 






950 


65.15 


2.37 






1.000 


67 .52 












.05 




(OSC-8) 


1,050 


67 .57 


3.34 






1,100 


70.91 












1.46 






1.150 


72.37 












3,15 






1,200 


75 .52 




11.62 


.154 



Mi 



square miles 



- 80 - 



Table 3 

Arithmetic Averages of Basin Snowpack 
Indices by Survey Periods 







BASIN INDEX 




Survey 
Period 
(Date) 




- Average - 




Depth, D 
(in.) 


Water Equivalent, 
W (In.) 


Density, ^ 
(in.) 


2.1.69 


12.7 


2.8 


mMMi 


15.1.69 


14.4 


3.3 


[ 


27.1.69 


8.1 


2.5 


m \ 


5.2.69 


8.i 


2.1 \ 


M ! 


26.2.69 


5.2 


1.3 




14.3.69 


4.0 


1.4 


■- 


24.2.69 


0.0 


0.0 


#ii 



- 81 - 



Table 4 

Weighted Averages (by Thlessen's Method) 
of Basin Snowpack Indices by Survey Periods 







BASIN INDEX 




Survey 
Period 
(Date) 




- Weighted Average - 




Depth, D 
(In.) 


Water Equivalent, 
VI (in.) 


Density, d 
(in.) 


2.1.69 


12.5 


2.7 


.12 ' 


15.1.69 


13.7 


3.2 


.23 


27.1.69 


7.5 


2.3 


.31 


5.2.69 


7.1 


1.8 


,23 


26.2.69 


4.2 


■1 

1.1 


.21 


14.3.69 


3-3 


1.2 


.29 


24.3.69 


0.0 


0.0 


.00 



- 82 - 



Table 5 

Weighted Averages (by Area -Elevation Method) 
of Basin Snowpack Indices by Survey Periods 







BASIN INDEX 




Survey 
Period 
(Date) 




- Weighted Average - 




Depth, D 
(in.) 


Water Equivalent, 
W (In.) 


Density, d 
(in.) 


2.1.69 


13.0 


2.7 


.22 


15.1.69 


14.4 


3.2 


.23 


27.1.69 


8.2 


2.4 


,31 


5.2.69 


8.2 


2.0 


.23 


26.2.69 


5.3 


1.4 


.21 


14.3,69 


4.0 


1.1 


.27 


24.3.69 


0.0 


0.0 


.00 



- 83 - 



Table 6 



Area-Isohyat Dlstrlbutlori and 
In Weighted Average Snowpack Depth by 
Survey Periods 



< 


;,, 


AREA EMCLOSED 


SNOW 


DEPTH 








Weighted 






1 ; 






Average 


Survey 








Average 


(Accumula- 


Period 


Isohyet 


2 




Isohyet 


tive) 


(Date) 


(in.) 


Mi 


% 


(In.) 


(in.) 


2.1.69 


10.0 


i 






! 






36.3 


48.0 


10.9 




•( 


12.0 












14.0 


23.1 


30.6 


13.0 








5.8 


7.7 


15.0 


,1 


i 


16.0 














3.8 


5.0 


17.0 






18.0 














6.5 


8.7 


18.1 


12.8 




20.0 










15.1.69 


10.0 


; 












15.1 


20.0 


11.1 


i 




12.0 








\ 






25.3 


33.5 


13.0 






14.0 














15.5 


20.6 


15.0 






16.0 














7.8 


10.3 


17,0 






18.0 














4.6 


6.1 


19.0 






20.0 












■ 


1 '■' 


9.5 


20.3 


14.5 



- 84 - 



Table 6 (cont'd) 







AREA ENCLOSED 


SNOW DEPTH 








Weighted 






' 






Average 


Survey 








Average 


(Accumula- 


Period 


Isohyet 


Mi2 




Isohyet 


tive) 


(Date) 


(in.) 


% 


(in.) 


(in.) 


27.1.69 


4.0 


. 


) 








1 


6.0 


19.1 


25.6 


4.9 


i 






23.1 


31.0 


7.0 




; 


8,0 














16.6 


21.0 


9.0 






10.0 














6.8 


9.0 


11.0 






12.0 














8.4 


11.2 


13.0 


; 


i 


14.0 








t 






1.5 


2.2 


14.0 


8.1 














5.2.69 


4.0 














31.2 


41.4 


5.0 


• 




6.0 








■ 




8.0 


18.9 


25.0 


7.0 


/ 






10.0 


13.2 


9.0 






10.0 












12.0 


3.3 


4.4 


11.0 






14.0 


3.0 


4.0 


13.0 








3.0 


4.0 


15.0 


1 




16.0 














6.1 


8.0 


17.0 


7.9 















- 85 - 



Table 6 (cont'd) 



' 




AREA 


ENCLOSED 


SNOW DEPTH 








Weighted 


ll 




i 






Average 


Survey 








Average 


(Accumula- 


Period 


Isohyet 


2 




Isohyet 


tive) 


(Date) 


(in.) 


Mi^ 


% 


(in.) 


(in.) 


26.2.69 




13.4 


17.6 


1.0 








2.0 














30.4 


40.3 


3.0 






4.0 














15.9 


21.0 


6.0 






8.0 














7.8 


10.3 


10.0 






12.0 














5.4 


7.1 


14.0 






16.0 














2.6 


3.7 


16.2 


5.3 


14.3.69 




34.0 


45.0 


1.0 






1 


2.0 










i 


i 


11.2 


14.8 


2.0 


,1 




4.0 














14.1 


18.6 


6.0 






8.0 










ii 




8.5 


11.3 


10.0 


' 




12.0 














7.8 


10.3 


13.5 


4.4 



- 86 - 



ONTARIO WATER RESOURCES COMMISSION 
DIVISION OF WATFR RESOURCES 

INTERNATIONAL HYDROLOGICAL DECADE 

EAST AND MIDDLE OAKVILLE CREEKS 
DRAINAGE BASIN 




Figure 1 . Isohyets of snovvpaek depth in inches - Survey period 2.1 .69. 



-^^^..-^rv>^ 






ONTARIO WATER RESOURCES COMMISSION 
DIV SION or AATER RESOURCES 



INTERNATIONAL HYDROLOGICAL DECADE 

EAST AND MIDDLE OAKVILLE CREEKS 
DRAINAGE BASIN 




Wnil" 



Figure 2. Isohyets of snowpack depth in inchas- Survey period 15.1 ,6§. 




Figure 3. Isohyets of snowpack depth in inches - Survey period 27.1 .69. 



ONTARIO WATER RESOURCES COMMISSION 
DIVISION OF WATER RESOURCES 

INTERNATIONAL HYDROLOGICAL DECADE 

EAST AND MIDDLE OAKVILLE CREEKS 
DRAINAGE BASIN 




Figyre 4. Isohyets of snowpack dspth in inches - Sorvey period 5.2.69. 




79*43' 













ONTARIO WATER RESOURCES COMMISSION 
DIVISION OF WATER RESOURCES 



INTERNATIONAL HYDROLOQICAL DECADE 

EAST AND MIDDLE OAKVILLE CREEKS 
DRAINAGE BASIN 



2 Miles 




Bnrlingtt 
Dundas 
HAMILTON 



KEY MAP 

Scale 1:1.000,000 



_^ , ^ i^-« — i::^ , L^ ^^ H-i— ' ^-r- ■ — ^ 




z a\ 



Figure 5. Isohyets of snowpack depth in inches - Survey period 26.2.69. 



ONTARIO WATER RESOURCES COMMISSION 
DIVISION OF WATER RESOURCES 



INTERNATIONAL HYDROLOGICAL DECADE 

EAST AND MIDDLE OAKVILLE CREEKS 
DRAINAGE BASIN 



] 2 Miles 




Figure 6. Isohyets of snowpack depth in inches - Survey period 14.3.69. 



*TtT3tDDDDDT15fl«