SLIDE NOTES
10
Title
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Small islands do not have any significant surface water sources and as a result generally
rely on groundwater and rainfall capture for potable water supplies. The fact that groundwater
is obviously hidden from view and therefore invisible makes it poorly understood by the nonspecialist. Another complicating factor for small islands is that rainfall is often highly variable
and as a result hard to manage.
12
The Pender Islands encompass the range of water issues found on small marine islands
The Penders have a mixture of water distribution systems in a complex legal and institutional
(government) framework (system). The geology and as a result the groundwater is perhaps
more complex than many small islands.
Key Questions to ask include:
•What are the groundwater resources?
•How can groundwater resources be determined in a cost effective manner?
•Where do groundwater resources occur?
•Who and what control groundwater resources?
•How can knowledge of groundwater resources be incorporated and implemented into
community plans?
13
Although it sounds relatively simple, the fact that water runs downhill is a very
important part of the groundwater assessment process and should play a role in any water
management strategy for the Penders.
Fresh water is not as dense as salt water and as a result floats on top of salt water.
The province owns all of the water but it has been incredibly slow in enacting legislation for
groundwater. Until recently it was the only jurisdiction in North America that had no
groundwater legislation
Ultimately the only source of freshwater for the Pender Islands is rainfall. It is what replenishes
the groundwater supplies and the levels in water wells will vary with the amount of rain.
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List of Groundwater Issues
15
One of the purposes of this slide is to illustrate the complexity of groundwater
management. There are 3 major components: Physical Setting, Risk, and Governance. The
major components cannot be treated individually but are very closely tied to one another.
Within each major component, there are sub-components that are also highly inter-related. For
the Physical Setting, the components are Climate, Geology, and Geophysics; for Governance, the
components are legal and institutional; while for Risk, the components are drought, seismic
activity (earthquakes) and contamination which includes salt water intrusions.
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So to discuss the physical setting first, this is a list approaches to assist in better
understanding the physical setting to enable a better understanding of the groundwater
resources.
Airphotos for the Penders from the 1930’s exist and are useful since there was little
development then and the airphotos can be used to map geology and geologic structures such
as faults that play a large role in groundwater.
Remote sensing in conjunction with airphotos can be used to identify vegetation that indicates
the location of springs.
Geologic mapping provides an understanding the soil and bedrock types which determine how
much groundwater can be stored and where
Geophysics can be used to provide information on geology in areas where the geology is hidden
under the ground. On the Penders it was very useful in determining how far below ground
surface salt water occurs; an important piece of information because the entire island is
ultimately underlain by salt water.
Reviewing the existing water well data provides more information on availability of
groundwater. The water well records when I was doing my research had not been kept up to
date and were only available to about 1996 or 10 years out of date.
Climate records have been kept for the Penders since about 1925 and in recent years by island
residents/communities.
All of the geology mapping needs to be tied to laboratory data to get a better understanding of
what the porosity of the different bedrock and soil types may be which determines what the
storage capacity of groundwater will be as well as the permeability which determines how
connected the pore spaces are which determines how much of the groundwater can be
accessed.
17
This slide simply illustrates the interrelationship between the various natural processes
that impact groundwater. What this slide also illustrates is that a change in any one process will
result in changes to all other processes.
The interrelationships presented become significantly more complex when viewed with the
varying space and time scales involved. Impacts from a change in one process may not be
noticed within a specific time frame until it is impossible to alter the outcome without
significant expenditure of human capital.
As an example, since groundwater resources are invisible, often slow moving and generally not
well monitored, it has been found that there can be a significant time lag before negative
impacts are noticed.
18
As mentioned previously, rainfall represents the only source of fresh water and
replenishment of the aquifers on the Penders. As such it represents a very important part of this
presentation. As you are aware the climate changes with the seasons and from year to year.
There are other elements of climate such as temperature which are also important as they have
an influence on how much water from rainfall actually makes it to recharge groundwater.
19
This has been a particularly bad year from a rainfall perspective.
20
The hydrologic cycle can be defined by the water balance equation, also known as the
hydrologic equation, which simply states (Domenico and Schwartz, 1998):
Inputs = Outputs + Changes in Storage
(1)
The inputs to the water balance equation for many small islands are restricted to precipitation
(Falkland, 1991).
Since the climatic factors controlling water supply on small islands vary both spatially and
temporally, this variation poses many problems for management of the resource
This equation for water balance can be viewed just like a bank account; what is deposited is
equal to what is withdrawn plus the bank balance. If more is taken out than deposited then the
balance in the account shrinks. It is no different with the groundwater resources; there is simply
no bank book to provide a balance of the account.
Similar to a bank account there are other outputs which in banking might simply be called
service fees whereas in the water balance there are outputs from evapotranspiration
21
Since inputs to the water balance equation for many small islands are restricted to
precipitation (Falkland, 1991) the water balance equation can be rewritten
where P = precipitation, R = surface runoff, O = groundwater outflow, G = change in
groundwater storage, S = change in soil moisture, I = interception, C = communication with
surrounding area, M = water recharge/discharge due to human activity, and E =
evapotranspiration.
Changes in land use patterns have impacts on surface runoff, infiltration, evapotranspiration,
and can ultimately alter the local climatic conditions.
22
The key to this slide is the interrelationship between climate, water resources, water
management and water and land use. The tie to water and land use illustrates the importance
of what will be referred to as institutional or government involvement.
23
This slide presents the average monthly rainfall over about a 75 year period for North
Pender. Rather than use a calendar year, it starts in the spring on the left and ends in the winter
on the right. This simply helps to keep the fall and winter rains together and they are very
significant in that it is the fall and winter rainfall that plays the major role in replenishing the
groundwater bank account.
A comparison of the average monthly precipitation for wet (October to March) and dry (April to
September) periods indicates that 75% of the average annual rainfall occurs during the October
to March time frame
The seasonal nature of precipitation is significant. During the dry months, the population of the
islands tends to triple, due to the influx of tourists, placing increased demands on water supply
when there is the least potential for replenishing that supply
The seasonal nature is also important for the timing of drilling a water well to prove that
sufficient water is available for a given lot. A well drilled in March will look much better than a
well drilled in September after a long dry summer.
24
Unfortunately I have not had the opportunity to update the rainfall for the period 2003-
2015. This slide presents the annual rainfall for the period 1925-2002. There are a few gaps in
the data. The key year is 1943 when there was a severe drought on the Penders.
Recent studies on the Athabasca River drainage area using tree rings have found that during the
past 900 years there have been a number of severe droughts that have not been repeated in
recent history but which management plans should be prepared for.
Of particular note is the average annual rainfall is an amount that rarely ever falls on the
Penders. The actual rainfall is generally either higher or lower. This would indicate that using the
average annual rainfall for planning purposes may be a mistake. It might be better for planning
purposes to use the precautionary principle and select a number that is closer to the minimum
annual rainfall.
25
Since precipitation is the only source of replenishment for groundwater supplies, it is
important to investigate the dry periods in more detail. As Dracup et al (1980) stated, the study
of droughts has been seriously neglected.
Droughts should be closely tied to security of water supply issues. Koshida (1991) defines
droughts as prolonged periods of abnormally dry weather producing a moisture shortage that
affects crops and forests, and reduces water resources to a degree, thus creating serious
environmental, economic or social problems.
The most severe drought conditions on record occurred between August 1942 and September
1944, when population on the islands was low. During this period 50% of the months received
less than 60% of the average monthly rainfall and the majority of these months were the winter
months. For the period September 1943 to September 1944, the only month that did not
receive less than 60% of the monthly average rainfall was October 1943.
26
The monthly precipitation statistics presented in this slide illustrate the chaotic
distribution. The range of precipitation for each month is very large. A review of the per cent of
recorded precipitation data for each month indicates that during the summer months of July
and August, there are drought conditions every second summer, on average. This figure
decreases to every third spring and fall and every fourth winter. It also appears that
precipitation varies least from the average for December. This is significant, since the winter
months are when the groundwater supplies are replenished on the island. These statistics are
also important from a planning perspective, in that they indicate that drier than normal
conditions can be anticipated on a regular basis for all months.
Solley et al (1998) provide a water relation of 25.4 millimetres (1 inch) of rain equalling
approximately 25 million litres of water per square kilometre. In view of the average annual
precipitation of 803 mm for North and South Pender Islands, this translates into 813 million
litres of water per square kilometre, a significant volume of water. On the sole basis of these
calculations, there should be no shortage of water resources on the islands, and a water
resource assessment would be a waste of both time and resources. It is, however, important to
refer back to the water balance equation. Its variables indicate that a large portion of
precipitation does not necessarily contribute to groundwater recharge; instead, much of the
water is lost to other aspects of the hydrologic cycle, such as evapotranspiration, surface runoff
and the soil moisture conditions at the commencement of a precipitation event.
th
This is a map of drought conditions in B. C. for August 7 of this year and the Penders
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were in Category 4 drought conditions.
28
Outline of Category 4
29
Temperature is not directly related to the water balance equation but it is a controlling
factor for evapotranspiration and additionally, temperature impacts the type and distribution of
vegetation. Vegetation, in turn, influences surface runoff, interception of precipitation, and
evapotranspiration.
Temperature records for North Pender Island are only available from 1971 to 1994.
0
0
The average annual temperature ranges from 8.7 C to 11.2 C. Given the short duration of the
temperature records, it is difficult to make any inferences on the average annual temperature.
0
The average monthly temperature ranges from a low of 4 C in January to a high of
30
0
16.5 C in July and August (Henderson, 1998). The warmest months occur during the driest part
of the year. As will be discussed in Section 4.2.3, the warmest months also have significant
evapotranspiration which can result in net moisture losses during the warm, dry summer
months.
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Evapotranspiration is defined as the process by which water moves from the soil to the
atmosphere.
Evapotranspiration is a complex and ambiguous component of the water balance equation, it
should be pointed out that all methods of calculating evapotranspiration provide only estimates
of the average evapotranspiration. For North and South Pender Islands on average as much as
64% of the annual precipitation may be lost due to evapotranspiration.
The range in evapotranspiration should, however be, compared to the annual
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precipitation. This ratio is referred to as the drying index and has an influence on the amount of
precipitation that is lost to surface runoff. The drying index ranges from 53% to 72%. If we use
the figure of 64% of precipitation lost to evaporation, then for an average annual rainfall, there
would be 293 million litres of water per square kilometre available. This number would be
further reduced by losses due to surface runoff, which can be significant due to the topography,
thin soil cover and human impact. For areas having little or no soil cover, the rocks are often not
capable of retaining water for subsequent evapotranspiration. When evapotranspiration is
combined with other moisture losses for variables of the water balance equation, only a small
percentage of the precipitation is available for replenishing water resources.
An understanding of the physical groundwater resource base ultimately provides the
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basis for defining management options.
Geology includes:
•
Variability of soil type and thickness
•
Bedrock type
•
Porosity and permeability of different bedrock types. Island specific geology controls the
primary porosity and permeability which in turn constitutes the major limits to storage
capacity of groundwater resources. Primary porosity and permeability are related to
inter-granular spaces
•
Identification of fault and jointing patterns (structure) (secondary porosity and
permeability which are where the best water wells on the Penders are located.
Secondary porosity and permeability are related to openings created after the rock was
formed.
•
Depth to water table
•
Depth to salt water
Many of the topographic highs have little or no soil cover, and its absence has implications in
terms of vegetative cover as well as surface runoff/groundwater recharge.
34
The bedrock geology of the study area consists of poorly sorted, massive sandstone,
shale and conglomerate of the Nanaimo Formation of the Upper Cretaceous age (approximately
80 million years ago) (Halstead and Treichel, 1966). The bedrock geology plays a large role in
the topography of the islands, with the steep rugged topography following the trends of the
major resistant bedrock units (sandstones and conglomerates); the valleys are located over less
resistant shale and along fault lines (Williams and Pillsbury, 1958).
The bedrock geology of North and South Pender Islands consists of essentially non-porous,
impermeable sedimentary rock in a complex, tectonically active area.
The general lack of primary porosity and permeability for the bedrock units on North and South
Pender Islands indicates the reduced potential for water storage and accessibility.
35
This is a geologic cross-section of the bedrock geology between Thieves Bay through
Shingle Point to Clam Bay. Between Thieves Bay and Shingle Point the bedrock is very steeply
dipping. There is a fault in Shingle Point as well as faulting in both Ella Bay and Otter Bay. These
faults have resulted in an offset in the bedrock at depth. On the east side of the island near
Calm Bay the bedrock does not dip as steeply as on the west.
What is important is the location of the faults and the contacts between the different bedrock
formations as these are generally locations of increased porosity and permeability.
36
This is a different geological cross-section of the bedrock between Swanson Channel
towards Medicine Beach and Port Browning then to Auchterlonie Point. The Pender Fault is
intersected in Port Browning while the Allison Fault is located east of Port Browning. As in the
previous cross-section, the bedrock dips more steeply in the west than in the east.
37
As we move farther to the south, this geological cross-section illustrates the bedrock
geology between Wallace Point in Trincomali across Bedwell Harbour to the about the midpoint of the east coast of South Pender Island. There are 3 faults with the Pender and Spalding
Faults being the most significant from a groundwater perspective. In general terms the bedrock
dips to the east.
38
The last geological cross-section is at the south end of South Pender and goes from
Gowlland Point in the west to Teece Point in the east. It intersects 4 faults although the Pender
Fault is now located beneath Plumper Sound. This is significant in that it indicates that the
Pender Fault has the potential farther to the north to be a pathway for saltwater to move
inland.
39
Just to illustrate that I wasn’t making up the fact that the bedrock is not flat lying this
slide illustrates a deeply dipping bedrock shale unit.
40
There may be as little as 0.5% of the precipitation available to recharge groundwater
aquifers. This would still translate into 4 million litres of water per square kilometre. If it is
assumed that each resident uses 75 litres of water per day, and that the average lot size is one
acre having two persons per residence, then the human requirements on an annual basis would
be approximately 13.5 million litres of water per square kilometre. This simple calculation would
indicate that at full build out there would be a groundwater deficit of 8.5 million litres per
square kilometre assuming that no other water sources. If we were to examine 1943, the driest
year on record on North and South Pender Islands, then the water available at an estimate of
0.5 % of the rainfall, would be 0.85 million litres per square kilometre before human
consumption. There would be a deficit of 12.65 million litres per square kilometre after human
consumption.
Natural recharge on North and South Pender Islands comes from deep percolation of
precipitation. Deep percolation is influenced by a number of factors, including the texture of
near surface materials and their permeability, the vegetative cover, the frequency, intensity and
volume of precipitation, topography, and temperature (American Society of Civil Engineers,
1996). When recharge is equal to discharge then groundwater conditions have achieved a
steady state. Human activities such as water well withdrawals, change this equilibrium and can
only be accounted for by increased recharge, decreased discharge, or some combination of
these two.
41
So how does the bedrock geology and structure impact water resources for the islands?
It gets back to the initial part of the presentation and the truth that water runs downhill.
Rainfalls on the island and follows the path of least resistance by entering fault and fractures in
the bedrock as well as seeping into the soil to get into the underground plumbing that makes up
the bedrock aquifers for the islands.
Unfortunately for the Penders, there are no places with thick soil cover. As a result the reliance
then is on the interconnectedness of the fractures that contain the most water.
42
The purpose of this slide is to stress a popular misconception that what I do on my
property has no impact on my neighbours. If my well is deeper than my neighbours and I
overpump my well then I have the potential to make my neighbours well run dry by drawing
down the water levels. This can create a huge headache from a water management perspective
as how can non-enforced regulations protect individual well owners.
43
The following few slides present some of the current issues in water resource
management. The slides indicate the relative importance of the legal and institutional
frameworks under which groundwater management exists, as well as the significance of the
relationship of water to the overall environment.
This slide lists some of the issues related to water availability, requirements placed on water and
water use.
44
Idea of integrating geology and geophysics in resource assessment is not new; it is
routinely used in oil and gas and mineral exploration and development
Geophysics is however rarely used in groundwater assessment and it should be noted that it is
not mentioned in the aquifer classification guidelines for B.C.
45
Objectives of Geophysics
46
On small islands, another concern is the location of saline water (Fitterman and
Hoekstra, 1984; Mills et al, 1988). Fresh water is less dense than salt water and as a result
generally forms a lens floating on top of the salt water (Falkland, 1991). The depth to the salt
water has been estimated by the Ghyben-Hertzberg equation:
hs = (Pf / (Ps-Pf))(hf)
(3)
where hs is the depth of freshwater below sea level, Pf is the density of freshwater, Ps is the
density of sea water, and hf is the height of the freshwater table above sea level (ASCE, 1996).
The Ghyben-Hertzberg equation can be used to provide an estimate of the freshwater column
thickness. This estimate can be useful in determining optimal depths and pumping rates for
water wells to limit the risk of saline intrusion as well as in enabling a better understanding of
the groundwater resources available.
47
This is an example of a time domain electromagnetic sounding measured at Roesland.
Without going into a really detailed explanation of the method and watching everyone’s eyes
glaze over I will only touch on the critical points. Time domain electromagnetics is used to find
conductors and salt water is a very good conductor. The portion on the left of the slide
corresponds to the raw data. Measurements were made at different times and with increasing
time there is an increase in depth of exploration. The dots represent the measurement points
and the lines represent the model fit of the data. On the right portion of the slide, the solid line
represent the model used to fit the data points and the dotted lines represent models that
would also fit the data set reasonably well. What is important is that there is little or no
variation in the depth to the bottom layer which has a resistivity slightly above 1 ohm-m. There
are very few things in nature that have resistivities this low but salt water is one of them and as
a result, the depth to salt water at this location is about 56 m.
This gets back to what the truths about water are and the fact that freshwater is lighter than
salt water and therefore floats on top of saltwater.
48
I had to include this conceptual model for medicine beach as it is a unique ecosystem on
North Pender. The salt water marsh exists because there is a clay layer that does not allow salt
water to migrate downward by essentially trapping it near the ground surface. There is
freshwater that flows underneath the slat water marsh and ends up in the ocean offshore from
Medicine Beach.
The conceptual model is actually backed-up by geophysical measurements that were made
along the beach at low tide.
49
This slide illustrates how overpumping can cause an upwelling of saltwater in a water
well. This slide is taken from a report prepared for the district of Nanaimo and does not
represent the typical water wells on the Penders since most water wells on the Penders get
their water from fractures in the bedrock. There are ways to combat saltwater intrusions for a
widespread aquifer in soils but there is not much that can be done for individual water wells in
fractured bedrock. Consultation with some experts in hydrogeology provided some interesting
insight. They basically stated that if it took 15 years of pumping to result in the saltwater
intrusion that it would take 15 years of no pumping to have upwelling of saltwater decrease a
little. On this basis for residents along the coast line, pumping rates and monitoring of the
salinity of the well water should be a prime concern.
50
Population Growth
The community plans for the island list 2101 lots, with a projected
total population of approximately 4200 persons at full lot development (Islands Trust, 2003).
The permanent resident population, as of the 2001 census, was listed as 1776 (Islands Trust,
2005).
The most recent perspective from Islands Trust is that not all lots will be developable and as a
result the population at full lot development will be reduced.
51
North Pender Island occupies an area of 2,728 hectares. It has the highest population
density of any of the Outer Gulf Islands at 0.51 persons/hectare. This slide illustrates both the
approved lots as well as the groundwater vulnerability. Not all of the high groundwater
vulnerability areas are restricted to along the coastline. The area around Port Washington, Hope
Bay, Trincomali, Razor Point, and MacKinnon Road are all in groundwater vulnerable areas.
One of the risks associated with maps is that the information presented may be accepted as
factual, when in reality, it is not. The groundwater vulnerability map is an example, in that it
does not indicate significantly high risk in the vicinity of known faults. It is well established that
secondary porosity and hydraulic conductivity may increase substantially in the vicinity of major
faults, enabling migration of contaminants and therefore increased groundwater vulnerability.
The maps also do not include areas of known water quality issues as presented by Mordaunt
(1981) and Henderson (1998); those areas should be shown as having increased groundwater
vulnerability
52
This slide illustrates the development potential for North Pender. The pink areas are
parks or protected areas while the green areas are deemed to be agricultural. There is some
overlap between some of the agricultural areas and high groundwater vulnerability
The groundwater vulnerability map is much more useful when viewed in combination with the
sub-division potential map for North Pender Island (Figure 6.7). There are several regions of
North Pender Island possessing both a high degree of groundwater vulnerability and subdivision potential. An example is in the vicinity of Port Washington and is indicative of the lack
of integration of groundwater resources into the community planning process.
53
The combined protected, agricultural reserve, and forest reserve lands on North Pender
Island comprise 28% of the landmass of the island. This portion of the island would currently be
unavailable for residential development. This amount of land represents approximately one
half of the proportional land that would not be currently available for development on South
Pender Island.
54
Since the island has 2101 lots (Islands Trust, 2004), it would appear that the water well
database does not include all water wells. Thirty-eight lots have had multiple water wells
drilled, and these account for 94 of the 504 wells (18.6%). That figure indicates either poor
production or a decrease in water quality in the initial water well necessitating additional
drilling. This situation translates into the water well’s database including information from a
mere 21% of the lots on the island. This number may also reflect the fact that 1241 lots are
located within Magic Lake Estates, which has a community water supply system. Perhaps not as
many water wells have been drilled in Magic Lake Estates. Nevertheless, the limited percentage
of lots with water wells in the database cannot be explained solely by the potential lack of
water wells from Magic Lake Estates. There is clearly water well information that has not been
included in the database. In view of the number of lots on the island, the ratio of water wells to
lots is one water well per four lots.
On the basis of the water requirements per lot as listed in the Official North Pender Island
Community Plan, approximately 10% of the water wells listed in the data base would not meet
current requirements for water supply,
It should be remembered that production of water does not necessarily translate into water
supply; these figures provide no information regarding water quality.
55
the statistical information presented can clearly be used to argue for either sufficient
groundwater resources to allow additional development or for limited development based on
poor productivity for a large number of water wells.
The range of productivity varies between 0.0 lpm and 378.5 lpm (100 gpm), but a histogram of
well productivity shows that the data are skewed to the right indicating that most wells are
generally considered to be poor producers (Figure 4.17). The average productivity of the water
wells is 17.87 litres/minute (4.72 gallons/minute), which would easily meet the daily
requirements for most residents. If the 41 best producing water wells are subtracted and the
average productivity re-calculated, the average drops to 10.18 litres/minute (2.69
gallons/minute) (see Table 4.11). This figure indicates that the subtraction of 41 out of 504
producing wells reduces the average productivity for the island by approximately 43%. Thus, a
few good wells can skew the average numbers for the island. The median productivity of the
water wells on North Pender Island is 7.57 litres/minute (2 gallons/minute),
56
subdivided the island into eight basic groundwater basins. The subdivision gets back to
one of the initial truths which is that water runs downhill.
57
Community Water Supply Systems There are 3 community water supply systems on
North Pender. Magic Lake Estates currently represents the highest population density on the
Outer Gulf Islands. The current water supply for Magic Lake Estates is Buck Lake. To ensure
security of supply for the community, a reserve was placed on Roe Lake. Magic Lake is currently
used as a supplemental water source for Buck Lake.
The Razor Point Road Development dates back to the 1960s. It consists of 31 properties, of
which 27 have been developed. The water supply for the development consists of a single water
well located in an adjacent development. Water pumped from the well is stored in a 4,540 litre
(1,200 gallon) storage tank and services the community through a gravity fed system of water
lines. A metering system has been established and is used primarily for leak detection. The
metering system also plays a role in the overall accounting system. The volume of water that is
pumped to the storage tank is recorded and compared to the volume of water consumed by
residents.
The Trincomali subdivision was established in 1968 and consisted of 104 lots. As of 1996, 79 of
these lots had been developed. The supply system comprised six water wells. The water from
these wells was pumped to two 45,450 litre (12,000 gallon) storage tanks located up slope from
the subdivision to allow for a gravity feed system.
Water meters have been used for several purposes, including identification of leaks and
recording daily consumption patterns. Daily consumption records of all residents are posted on
a bi-weekly basis on a community bulletin board and peer pressure is used as a means of
maintaining low levels of consumption
58
OW283
Observation well 283 is located in Port Washington is has been classified
by MOE as a type IIA aquifer which can be translated to be a moderately developed, high
vulnerability aquifer.
59
OW284
This slide presents the water level in Observation Well 284 located
on Pirates Road in Magic Lake Estates. It has been classified by MOE as a type IIB aquifer which
translates to a moderately developed, moderate vulnerability aquifer. It shows fluctuations in
water level from 1983 until the summer of this year. Up until about 2003 the pattern is relatively
consistent with recharge in the winter/spring and water levels falling off during the summer
months. That has changed since 2003 with the water levels in both the winter and summer
getting to progressively lower levels.
60
Currently, there are 281 residential lots, with 43 of these lots having the potential for
subdivision into an additional 191 residential lots (Islands Trust, 2002). The majority of the
residential lots are located along the coastline of the island. As previously mentioned, this
choice of location has implications from a water quality perspective, as there is a high potential
for salt water intrusions. Journeay et al (2004) have shown that there is a high risk of aquifer
contamination along the coastline of South Pender Island. Of the portion of the island available
for development, lot sizes vary, as they depend upon ocean frontage. Lots possessing ocean
frontage must be a minimum of 0.4 hectares in size, while lots without ocean frontage must be
a minimum of 0.8 hectares. The permanent resident population, as of the 2001 census, was
listed as 159 (Islands Trust, 2002). Agricultural reserve lands and forestry reserve lands
comprise 17.5% and 8% respectively of the island (Figure 4.4). In light of the current land use,
52% of the island presently dedicated to parks, agricultural reserve, and forest reserve, would
not be available for future development.
61
Responses to a questionnaire distributed by the local trustees of North Pender Island
show that a number of water wells cannot sustain the pumping rates listed in the water well
records, as some respondents have had their water wells run dry in the past (Henderson, 1998).
When combined with the statistical variability in water well production, this fact should raise a
flag about the usefulness of the statistics. On the basis of the available information, it would be
difficult or impossible to predict which water wells would run dry in any given year.
62
The current water well database maintained by B.C. Land, Water and Air provides
information on 165 water wells on South Pender Island. Of the total number of water wells on
record, 11 represent dug wells, which provide no information on water availability and often
little or no information on the soil type or depth to bedrock. There is a general tendency for the
early wells to have been either dug or drilled to a shallow depth, with most of the deeper wells
drilled in very recent times. The majority of the dug wells date to before 1950. The earliest
data is from a well dug in 1910, while the most recent data is from a well drilled in 1994.
Since the number of residential lots currently available is 281, it would appear that the water
well database does not include all water wells. At present, it is not required that water well
records be submitted to B.C. Land, Water, and Air for inclusion in the database, although the
submission of that information became a requirement in 2005 (B.C. Government, 2005). Eleven
lots have had multiple water wells drilled. Water well information is therefore only available for
approximately 50% of the lots on the island. It is unlikely that all water wells have been included
in the database.
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subdivided South Pender Island into groundwater basins (Figure 4.6). Each groundwater
basin encompasses a specific drainage/recharge area along with its soils, vegetative cover,
wildlife, land use and human activities. Water resource assessments in groundwater basins
represent a solid foundation for planning and management, but any groundwater resource
assessment represents only the conditions in place at the time of the assessment. Integration
of the geophysical data, geological mapping, precipitation records and groundwater wells within
each groundwater basin provides useful information that can readily be incorporated into
community plans. There are four basic groundwater basins on South Pender Island. On the
basis of the intrinsic vulnerability map produced by Journeay et al (2004), the only portions of
South Pender Island that possess a greater than moderate intrinsic vulnerability are located
along the coast line. Groundwater well data and structural mapping should be included to
increase the rated vulnerability along the fault line associated with the best producing water
wells.
64
For each groundwater basin, it is possible to calculate the storage capacity once the
bedrock type and its porosity are known. The information presented in Table 4.10 is only an
estimate of the storage capacity for each groundwater basin. These figures do not represent
the quantity of potable water available for human consumption.
65
The surficial materials encountered along Southlands Road (Figure 4.12) are interpreted
as clays (20 to 30 ohm-metres) near the surface, underlain by silty or sandy soils at depth. This
interpretation is based on increasing resistivity with depth. Agriculture Canada (1988) mapped
the surficial material as well drained gravelly, sandy loam overlying conglomerate. The
Agriculture Canada interpretation does not correlate well with the geophysical interpretation.
The geophysical interpretation is, however, consistent with the available water well information
on soil type.
The greatest depth to competent bedrock occurs in the vicinity of the channel-like feature.
Buried channels within the overburden represent zones of increased porosity and permeability
that may provide a useful source of freshwater for local residents.
The seismic refraction velocities for the competent bedrock vary between 3000 and 4700
m/sec. with the lowest velocities occurring beneath the channel-like feature. The channel was
likely responsible for increased weathering in the bedrock. That weathering would translate into
increased porosity and permeability and the channel represents a preferred drilling location for
water wells.
66
Groundwater Basins Groundwater basin SP-I occurs along the north shore of South
Pender Island and is separated from the remainder of the island by the topographic highs of
Mount Norman, Spalding Hill, and Hermit Hill. A major fault (Pender Fault) is located adjacent
to this basin and auxiliary faulting may be associated with the major fault, so that there may be
higher secondary porosity and permeability. Increasing secondary porosity and permeability
results in increased water production. The best producing wells form a linear pattern consistent
with the presence of faulting .
Groundwater basin SP-II (Figure 4.6) is situated in the central portion of the island. It is
bounded to the north by the topographic highs of Mount Norman, Spalding Hill, and Hermit Hill
and to the south by the topographic high of Curtis Peak. The underlying bedrock comprises De
Courcy Formation sandstones and conglomerates, Cedar Formation shales, and Protection
Formation sandstones. No water wells producing 37.9 lpm (10 gpm) or more are listed in the
water well database for this basin.
Groundwater basin SP-III (Figure 4.6) surrounds Greenburn Lake; the only surface water body on
South Pender Island. The underlying bedrock consists of Protection Formation sandstones,
Pender Formation shales, and Extension Formation conglomerates. No water wells in the water
well database with production rates of 37.9 lpm (10 gpm) or more are located within this basin.
Groundwater basin SP-IV (Figure 4.6) is located in the southern and eastern portions of the
island. It is bounded to the north by Stanford Hill. The basin is underlain by Extension
Formation conglomerates with low primary porosity and permeability. No major or minor faults
have been mapped within this basin.
67
The schematic presented in Figure 6.5 provides a more detailed description of the
interrelation of the groundwater basins, with South Pender Island as an example. That island
has been selected simply because there are fewer groundwater basins than on North Pender
Island. It is proposed that there be to have a Board of Directors for each groundwater basin.
The board members would represent the major stakeholders within each groundwater basin as
well as adjacent groundwater basins. Table 6.2 presents the recommended representation for
the Board of Directors for each groundwater basin on South Pender Island. The directors would
be required to reach a consensus on all water management issues. Additionally, no one board
member should have any greater power than any other. This model represents the application
of the collaborative planning process to groundwater management at a groundwater basin
level.
In case unanimity cannot be achieved, or a stakeholder group does not feel that it has been
adequately represented, it is necessary to have an appeal process in place. It is suggested that
the best mechanism would be a review panel consisting of representatives from off island, to
reduce any potential for bias or conflict. The review panel should include a representative of
Islands Trust, another from the provincial government, and the third member from a
groundwater basin on a different Gulf Island.
68
I have mentioned a number of times the importance of Governance in water
management so this part of the presentation will focus on the different levels of government
and government branches that have an influence on water management for the Penders.
69
Different levels of government influencing groundwater management
70
Water Management and Institutions Within the Outer Gulf Islands, there is no one
effective government agency responsible for water issues .
Sustainability implies the consideration of the needs of the entire community rather than the
needs of the individual. According to OECD (1998), this can be achieved through the promotion
of user “ownership” of water issues. As Henderson and Revel (2000) pointed out, the
Improvement District of Trincomali presently places the needs of the community as a whole
above those of any individual within the community.
71
Water Management and Institutions the most effective approach for altering water
consumption patterns is to combine top-down measures (i.e., regulatory controls, pricing) and
bottom-up strategies (i.e., education, information), with both occurring within a favourable
context (infrastructure).
72
There are a number of federal laws impacting water; the most relevant are the Fisheries
Act, the Canadian Environmental Protection Act, 1999, and the Health Act. Health Canada has
prepared a set of Guidelines for Canadian Drinking Water Quality (Health Canada, 2006).
Significantly, guidelines are voluntary and unenforceable, while standards are legally binding
and enforceable (Boyd, 2003). As a result, no jurisdiction within Canada is compelled to adhere
to the Canadian Drinking Water Quality guidelines.
There are federal lands on North and South Pender Islands including the following:
Pender Island Indian Reserve, South Pender Island
Greenburn Park, South Pender Island
Roesland, North Pender Island
These lands are administered by Indian and Northern Affairs in the first case, and Parks Canada
in the other two cases.
73
Provincial legislation relating to groundwater resources is widely fragmented throughout
a number of departments and agencies
Water Act
Drinking Water Protection Act
Health Act
Islands Trust Act
Highways Act Controlled Access Highways Act
Municipal Act Local Government Act
Agricultural Land Commission Act
Agricultural Waste Control Regulation
Farm Practices Protection Act
Energy Act
Water Utilities Act
Parks Act
Regional Parks Act
Land Registry Act
Land Titles Act
Pollution Control Act
Waste Management Act
Heritage Conservation Act
74
Local jurisdiction
These are all good statements but through a significant amount of
reading it is difficult to find how any of these might be implemented. The regulations only work
if enforced terms like should and encourage imply that there will be no new regulations to
enforce.
75
76
This is an excerpt from the Islands Trust prepared Gulf Islands Groundwater Protection –
A Regulatory Toolkit from last year. It uses a lot of the current buzz words but seems to promote
development which seems to be counter to groundwater protection. The aquifers on the Gulf
Islands have never been actually delineated so trying to establish development areas to protect
them seems like an interesting task.
The greatest lot density occurs along the coast line where the lots are smaller than inland and
the potential for saltwater intrusion is the greatest. The other obvious area is along any of the
faults in the bedrock as they tend to have higher porosity and permeability for greater
groundwater yields. These areas should not require further studies but should require constant
monitoring.
The term integrated water management planning is an interesting one as there is no agreement
among researchers what it actually means . For the community water supply districts
understanding both the surface water supplies and their relationship with groundwater can be
significant and this would apply to both Magic Lake and Razor Point. Rainwater management is
a very important aspect and it has been practiced for 4,000 years starting with residents of
Crete about 2,000 BC. The problem with rainwater management is that rainfall is unpredictable
and varies in both time and space. This makes it difficult to manage.
Government regulations are only useful if they are enforced.
77
From the same Islands Trust document, it is difficult to understand how when little is
known about the physical nature of the bedrock fractures that control groundwater supply that
cluster development can be recommended. The recent drought indicates that there is currently
insufficient groundwater resources to meet the needs of the current population without having
cluster developments.
The term encourage means that nothing is enforceable. There needs to be policies in place
along with economic incentives to have residents practice water conservation.
I should point out that the document also states that the policies developed in OCP’s are only as
good as the subsequent bylaws which again must be enforced.
78
It is likely too late for any of these bylaws to be effective since the islands are already
limited in additional development potential unless external water resources are available.
79
Once again the land use bylaws are stressing development when the reality may be that
with the limited groundwater supplies available for human consumption on the Gulf Islands
there may be little room for any additional development.
80
Given the potential land development map shown earlier in the presentation, there is
little or no room for further development which makes zoning of little or no use.
81
The major difficulty with the Water System Policies section of the Official Community
Plan is the lack of any definition outlining the procedures in place to carry out the policies listed.
The document does not state how the Trust Committee will support water supply systems,
water conservation, and education. It does not provide any references to the regulations that
may protect drinking water sources. The establishment of limits on the number of wells would
be impossible to regulate, since there has never been an assessment of the water supply
volumes on the island. In addition, the policies use phrases such as “shall be encouraged” and
“should be”. An example of the use of these phrases from the North Pender Island Official
Community Plan in Section 3.2.4 states “The quality of domestic water supplies and community
water systems ‘should be’ monitored regularly. Use of water saving devises is ‘encouraged’.”
These phrases indicate that all policies are voluntary and there are no penalties for not
voluntarily abiding by the policies.
82
In addition, proven water well production of 2045 litres/day/lot is less than the median
water well production for the islands. Thus, without a grandfathering clause, approximately
50% of the current lots would have insufficient water resources for development approval or
the issuance of a building permit.
83
B.C. Auditor General 2010
84
B.C. Auditor General 2010
85
B.C. Auditor General 2010
86
Aquifer Characterization Report 2012
87
Living Water Smart
88
Living Water Smart
89
Living Water Smart
90
Living Water Smart
91
Risks risks that impact groundwater encompass both water quantity and quality
Saline intrusions can be a result of overpumping of water wells or a natural response to
prolonged drought conditions. Salt water intrusion could also occur simply through the drilling
of a water well that is too deep from a well completed close to the freshwater/salt water
interface. Each of these situations could be circumvented by knowledge of the depth to the
water table and the depth to the freshwater/salt water interface.
The use of pesticides and herbicides should be prohibited to eliminate the potential for
groundwater contamination.
Seismic events (earthquakes) can impact water wells in a negative manner by changing
groundwater levels and reducing flow rates. These impacts can be of short or long term
duration
There is currently no drought management plan for either North or South Pender Island. Since
the climatic data for the islands indicate that droughts of varying degrees of severity have
occurred in the past (see Section 4.2.5), it would be prudent to develop a drought management
plan
If these risks are to be reduced, there is a need to understand the physical setting and establish
an institutional and legal framework based on this understanding that is supported both
politically and financially.
The last potential risk to be discussed is the possibility that changing legislation will over time
result in changes to lot size, and thereby increase sub-division potential or alter current landuse.
92
Given the recent wildfires caused by drought conditions in California, fire protection
should be of keen interest to all islands residents. The volume of water required to combat a
wildfire may end up being more than is readily available enabling the fire to grow and cause
significantly more damage.
93
A simple way to increase water supply is to decrease demand.
94
This slide has been borrowed from one of the flyers promoting this presentation. It
simply and effectively presents some of the options available to increase water supply through
reduced demand.
95
a list of means of water conservation including scientific and technical; economic; legal
and administrative; operational; educational; and political. These approaches are
complementary and work much better in tandem than individually.
Water saving devices for the individual household can significantly reduce water usage. These
include such features as low flow showerheads, waterless toilets, and efficient dishwashers and
clothes washers. Economic considerations for water efficiency and the resulting conservation
revolve around using pricing structures to control consumption. Chambouleyron (2003) states
that if the charge for water is not based on actual consumption, then the water user has no
incentive to reduce consumption.
96
The table in this slide presents a chart of water savings per household through the use of
higher efficiency water fixtures. It can quickly be seen that the increases in water efficiency
were high between 1970 and 1992, and somewhat lower between 1992 and 2003; this pattern
shows the law of diminishing returns.
The table is based on these assumptions:
1)
There are 2.7 persons/household.
2)
Based on an average of 37 minutes showering/person/week.
3)
Based on an average of 3 loads of laundry/person/week.
4)
Based on an average of 2 loads of dishes/person/week.
5)
Based on an average of 36 toilet flushes/person/week.
6)
Based on an average of 57 minutes of tap running/person/week.
Chaplin (1998) also notes that a study in Los Angeles found that graywater use could reduce
household consumption of potable water by 50%. The total annual saving per household if
changes had been made from 1970 to 2003 would be approximately 300,000 litres (79,260
gallons), which translates to about 820 litres/day/household (216 gallons/day/household).
Incorporating the use of gray water would double this figure.
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Water saving devices for the individual household can significantly reduce water usage.
Economic considerations for water efficiency and the resulting conservation revolve around
using pricing structures to control consumption. Chambouleyron (2003) states that if the
charge for water is not based on actual consumption, then the water user has no incentive to
reduce consumption.
It is often difficult to separate the influence of pricing policy from conservation measures, since
a well-conceived pricing scheme would also promote conservation (Cosgrove and Rijsberman,
2000). Tate (1990) states that use of water meters alone can reduce municipal water
consumption by 15 - 20% over pre-metering levels. The implementation of a block pricing
scheme would likely significantly reduce water consumption even further. Water efficient
plumbing fixtures have been proven to reduce water consumption (City of Calgary, 2002).
In 2015, the costs for metered water in Calgary have risen by 55% since 2005. while the costs for
unmetered water use have risen even more.
98
Conceptual Model
99
Recommendations
there can be a 10% reduction in water demand on the sole basis
of education. This reduction could mean the difference between maintaining the current water
supply system and requiring expenditure of significant capital to find alternative water sources.
The current database of water wells is of limited usefulness due to misinterpretation of bedrock
types and inadequate information regarding water bearing zones.
It would also be useful to have geophysical borehole logs included with new water well data, as
the water bearing zones would exhibit drastically different physical properties from the host
rock. The information gathered, if included in the water well database, would prove invaluable
to the understanding of groundwater flow and resource assessment in the Outer Gulf Islands,
and would consequently greatly enhance the planning and allocation of the water resources.
Without political support for groundwater management, it will be difficult to maintain a
reasonable groundwater management plan.
It would be prudent for residents and Islands Trust planners to establish emergency response
plans for natural disasters that may impact water supply on the islands. This should include:
droughts, floods, and earthquakes.
100
Recommendations
water meters in the Trincomali Improvement District and Razor
Point were useful in leak detection. Subsequent research for this dissertation found that the
water meters in the Trincomali Improvement District were an integral part of the water
accounting for the water supply system. Water meters on each water well would provide
information on pumping rates of the wells and on consumption, as well as establishing a basis
for the implementation of block pricing mechanisms
When the bedrock geology possesses steeply dipping horizons, it may be advantageous to
directionally drill water wells. This approach to drilling would encounter geologic boundaries
between formations more quickly. It is known that at the geologic contacts between
formations, there is often increased secondary porosity and permeability that may contribute to
enhanced water production.
Regular water quality testing, on an annual basis, for e-coli and total coliforms,
During severe water shortages, it may be necessary to limit the number of tourists visiting the
island at any particular time.
A number of small islands have used building codes as a means of increasing rainfall harvesting
and thereby decreasing reliance on limited groundwater resources. On North and South Pender
Islands, building codes could be adapted to ensure that rainfall harvesting occurred at the
individual property level. They could also be used to promote the use of gray-water for
functions such as toilet flushing that do not require potable water.
There should be strictly enforced regulations within the governing institutional framework to provide a
level of control for pumping rates. The installation of water meters for each residence would provide a
means of monitoring pumping rates. This same approach can also be applied to minimize the impact of
water well interference, which is also a result of overpumping.
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Benefits to Approach
102
Barriers to Approach
103
Barriers to Policy Implementation
104
Thanks