Investigating How Tidal Changes Affect the Chemical Composition of Water in
Zones 1, 3, and 5 of the Ala Wai Canal
Calvin Chan, Emily Cockey, Shayne Rasay, Janine Yim
AP Biology – Shimamoto Period 2
January 14, 2011
Abstract: The project investigated the effect of tidal changes on the chemical composition of
water (pH, salinity, turbidity, total dissolved solids, dissolved nitrate and oxygen concentration,
and conductivity) in zones 1, 3, and 5 of the Ala Wai Canal in Honolulu, Hawaii. A YSI sonde
collected data every 0.5 second for one minute at each of the zones over a period of three days,
once at low tide and once at high tide on every day. The experiment showed that pH and total
dissolved solids were unaffected by tidal changes. On the other hand, levels of dissolved oxygen
and nitrogen and salinity were higher at high tide whereas turbidity was higher at low tide.
Levels of salinity and oxygen were also found to be related as salinity levels rose at a higher rate
than the levels of dissolved oxygen. Turbidity was found to be inversely related to the dissolved
oxygen measurements in all three sites.
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I. Introduction & Research
The Ala Wai Canal is a small drainage estuary in Honolulu, Hawaii located at the western
entrance to Waikiki. It is a narrow artificial waterway created in the 1920s in order to to trap the
“combined drainage” of the Manoa and
Palolo Streams (Glenn CR, 1995). In
general, the canal is a “class A” saltwedge estuary, the most stratified of all
types of estuaries, affected by tidal
flushing (De Carlo EH, 1995). In a saltwedge estuary, fresh water floats on a layer of salt water that thins seaward and the denser
saltwater moves along the bottom of the estuary as it thickens landward (Mann, 2011). For the
purposes of this investigation the Ala Wai has been divided into five approximately equal sites,
with site five nearest to the mouth of the Ala Wai where the salt water flows into the fresh water.
One of the chemical properties of water calculated is pH and how it changes at different
tides. pH measures the hydrogen ion (H+) concentration on a logarithmic scale from one to
fourteen. The pH of a solution is neutral at seven
indicating that the H+ concentration is equivalent to
the hydroxide (OH-) concentration. When pH is below
seven, a solution is acidic because the concentration of
H+ is greater than the OH- concentration. Vice versa,
when pH is above seven, the solution is basic as the
OH- concentration is greater than the H+
concentration. Each step on the pH scale is ten times
3
more intense than its predecessor. In other words, a pH three solution is ten times more acidic
than a pH four solution (Senese, 2010).
The optimum pH differs in all bodies of water. Depending on the pH, different organisms
live in certain areas. Most waters have a pH range from 6.5 to 8.0 The range of pH can however
vary due to certain conditions such as acid rain (lower pH) and waste dumped into the water,
which can potentially harm the organisms that are used to living with a certain pH. Organisms
function best at a constant pH so buffers that prevent variation in pH are important in all bodies
of water. The property that indicates a body of water’s ability to maintain a stable pH is called
alkalinity. A high alkalinity is beneficial to organisms and can be produced by certain rocks and
salts that aid in the buffering process (Addy, 2003).
Another water property observed is
salinity. Salinity, or the measure of salt
concentration, varies in estuaries due to
geographic location, tides, and weather
(National Ocean Service, 2008). In general,
salinity varies according to one’s position
near the ends of the estuary. By
convention, sea water has a rather consistent salinity of approximately 32 - 35 ppt, or parts per
thousand and fresh water has a salinity closer to 0 ppt (Richard Stockton College, 2010). Thus,
the source of ocean water at the mouth of the estuary has the highest salinity while the source of
fresh water found further inland has the lowest salinity.
Tides also affect the salinity. During ebb tides, in which river water flows towards the
mouth of the estuary, salinity decreases inland. In flood tides, in which sea water flows inland,
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salinity increase near the mouth of the estuary (Richard Stockton College, 2010). Hence, the
distribution of salinity regions fluctuate with tides. Weather also changes salinity. During
seasons of high precipitation, excess water dilutes the concentration of salt in the water, thus
causing salinity to decrease. When temperatures rise, evaporation of water increases, which
leaves more solute in the water and thereby increases salinity. Hence, wetter seasons typically
decrease salinity and warmer seasons increase salinity.
Salinity has a variety of effects on organisms and the solubility of solutes. One
determinant of an organism’s survival in an environment is its ability to osmoregulate. In
estuaries, salinity changes frequently and spontaneously with environmental shifts. If the
ecosystem is hypertonic to the organism in salt concentration, water will flow out of the
organism through osmosis. However, if too much water flows out of the organism, the
organism’s cells may shrivel and die. If the ecosystem is hypotonic to the organism in salt
concentration, water will flow into the organism. When too much water enters the organism, the
organism's cells may become turgid for plants or lyse. While fluctuations in salinity have little
effect on organisms that have adapted to salinity changes via, for instance, contractile vacuoles
or active transport, changes in salinity may adversely affect the survival of organisms with low
tolerances to salt changes. A limited amount of solute can dissolve in a given solvent. When
additional solute molecules are added to a saturated solution, which contains the maximum
amount of dissolved solute, the molecules will not dissolve but crystallize. Hence, higher
concentrations of dissolved salt, leads to lower concentrations of dissolved solutes such as
oxygen and vice versa.
The third property investigated in the project was turbidity. Turbidity measures the
cloudiness of water due to suspended matter such as “clay, silt, finely divided organic matter,
5
microscopic organisms, and similar material” (American Public Health Association, 1917).
Measured in nephelometric turbidity units (NTU), turbidity is a measure of the amount of light
scattered by particles while traveling through water. As the amount of suspended substances
increase, the scattering of light and thereby turbidity increases accordingly (Murphy, 2007).
Bodies of water that appear relatively clear to the naked eye can have maximum turbidity
measure of 25 NTU while muddy water has a minimum turbidity measure of 100 NTU (Myre,
2006). Mainly due to its primary contributor, the Manoa drainage basin, turbidity levels in the
Ala Wai Canal are high (Lau, 2006).
High flow rates, soil erosion, urban runoff, waste water discharge, decaying organisms,
bottom-feeding fish, algal blooms, and flooding are all factors that affect turbidity. Hence, total
dissolved solids (TDS) values are closely related to turbidity. When a body of water has a high
flow rate (fast running water), the current is able to carry more organic particles and sediments,
which increases the amount of suspended substances on the surface of the water. Similarly,
eroded soil particles and other substances carried downstream from industrial, commercial, and
industrial communities by way of flooding increases the turbidity of the water. Water discharge
that contains solids and organic materials from waste water treatment plants has the same effect.
Within the water system itself, particles of decaying organisms, algal production, and the
presence of bottom-feeding fish that stir up sediments from the bottom all contribute to turbidity
(Murphy, 2007).
Another important chemical property of water researched was the total dissolved solids of
the estuary. The total dissolved solids (TDS) in water are directly related to the conductivity of
the water. The solids that are present in the water can be natural or man-made and can be
organic or inorganic. TDS is usually measure by evaporating a known value of the water and
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massing the remaining solute, but conductivity is also a viable, if not less accurate, measure of
TDS. Conductivity is the ability of a substance to carry a charge, and water’s conductivity
increases as more solids are dissolved in it to help carry the charge. The polar nature of water
makes it naturally conductive, but as the amount of solids increases the natural conductivity of
water increases due to an increase of ions (FM River, 2004).
Furthermore, the nitric oxide concentration of the canal was also investigated. Nitric
oxide, or specifically nitrogen monoxide, is a byproduct gas of industrial combustion as well as
the decay of organic materials. Nitrogen monoxide is a key molecule in many biological
processes ranging from signaling to organ protection, but can also cause death in higher
levels. The dawn of the industrial age and wide use of combustion led to an increase in
atmospheric nitrogen monoxide from the burning of nitrogen gas and oxygen. Beside the toxic
properties of the gas itself, the molecule can react with more oxygen to form nitrogen dioxide,
which in turn dissolves in water to make nitric acid (Sam Houston State University, 2010). The
concentration of nitrogen oxides can be an indicator of acidity of the water as wells as the
amount of organic matter that decays in water depending on the tide.
Finally, the oxygen and carbon dioxide concentrations were also observed. Dissolved
gases in the water are indicators of the biological processes that occur in the water. Saturation of
the water by dissolved gases can be increased by a decrease in temperature, decrease in salinity,
and increase in depth (Hurst, 2002). Carbon dioxide is a byproduct gas of cellular respiration as
well as an ingredient for photosynthesis and the reverse is true for oxygen gas. These two gases
are usually balanced in the water due to the photosynthesizing organisms that either consume the
oxygen present or have other organisms consume it. An increase in oxygen leads to an increase
of respiration in order to generate energy while an increase in carbon dioxide leads to an increase
7
of photosynthesis. Dissolved carbon dioxide also plays an important role in regulating sea water
and the atmosphere due to carbon dioxide’s reactions that control pH, rapid changes in carbon
dioxide concentration, and distribution of sediments (Hurst, 2002).
II.Materials and Methods
YSI multi-parameter probe (Sonde Model 6920 V2)
Data Display / Logger (YSI 650 MDS)
7.5 hp Zodiac Boat
6-foot aluminum rod to which YSI sonde is attached
1. The 7.5 hp Zodiac Boat was used to access the different zones.
2. The YSI sonde was secured to a 6-foot aluminum rod to place the probe at approximately
one meter in zones 1, 3, and 5.
3. The hand-held data logger stored data files at 0.5 second intervals for one minute in each
zone.
4. The experiment was performed over three days—twice a day during high tide and low
tide
III.Data
See the last page
IV. Discussion
According to the investigation, pH was not significantly affected by tidal changes. While
it fluctuates in a range from 0.0115 to 0.637 on November 13, 2010, in which there was outlying
data as found in standard deviation, there is no apparent pattern to this fluctuation in reference to
changes in the tide. Except for one outlying piece of data, pH of 4.92 in site one on November
13, 2010, which may have been attributed to faulty readings from the YSI or human error, the pH
remains at an average of 7.396, a pH that is well within the optimal pH for estuaries of 6.5 to 8.0,
regardless of day, tide, or weather. This is beneficial for the animal and plant life living in the
Ala Wai because it allows them to live in a stable environment. The stability of pH shows that
the Ala Wai has a high level of alkalinity and can support the constant lifestyle needed by
organisms such as those that live in the Ala Wai Canal.
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The salinity of the water did not follow a precise trend based on the sites’ positions from
the mouth of the estuary. The average salinity for all the data taken during high tide was 31.41
ppt deviating by only 5.42, while the low tide was 22.79 deviating by 16.33. On October 21,
2010, during low tide, site 1 recorded a salinity of 0.46 ppt, site 3 a salinity of 1.22 ppt, and site 5
a salinity of 1.66 ppt. During high tide, site 1 recorded a salinity of 16.33 ppt, site 3 a salinity of
29.23 ppt, and site 5 a salinity of 37.35 ppt. Data from sites during low tide on October 30 also
followed this trend. Since sea water has a higher salinity (between 32 – 35 ppt) than fresh water
(about 0 ppt), the closer a site to the mouth of the estuary, the higher that site’s salinity.
However, data collected on October 30, 2010 during high tide and November 13, 2010
did not follow this trend. Data from October 30, 2010 and November 13, 2010 showed that
salinity was slightly higher in sites during high tide (with the exception of site one on November
13). This data confirmed that during high tides more sea water enters from the mouth of the
estuary causing salinity in the estuary to rise. On November 13, 2010, the YSI multi-parameter
probe recorded a salinity of 0 ppt at site 1 at a tide of 0.52 m. High precipitation on the
14th caused an ebb tide in which water from the Manoa and Palolo Streams flowed towards the
mouth of the Ala Wai Estuary. The increase in fresh water at site 1 caused this extremely low
salinity.
The salinities at the sites during high tide on October 30 and November 13 were all very
close to 35 ppt (with the exception of site 1 on November 13). Although the Ala Wai is stratified
between freshwater and saltwater, it also contains areas in which the two waters mix. The higher
the tidal current is, the more mixing occurs. Hence, during high tide, the waters mixed
producing a nearly uniform mixture in salinity.
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Discrepancies arose because groups measured salinity at differing depths when data was
collected. Salinity at sites 1 and 3 during low tide on October 21 were significantly lower than
salinity at low tides on October 30 and December 11. Perhaps since tidal currents were low
during low tide, water at this time and at such a shallow depth (.46 m) was highly stratified with
fresh water floating on top the salt water.
When compared to the data on the other days, the salinity measured at the sites on
October 21 during high tide was extremely low. While such low salinity may have resulted from
a mistake on the YSI multi-parameter (since it was the group’s first time using the device), it
may have also resulted due to the high presence of dissolved oxygen. The higher the salinity, the
lower the percent of dissolved oxygen and vice versa. Hence, a limited solute can dissolve in a
given amount of solvent.
According to the data from October 30, 2010 and November 13, 2010 turbidity
measurements were higher during low tide for all sites. On Oct. 30, 2010 the biggest difference
between high tide and low tide measurements of turbidity was in Site 3 at 2.65 NTU; the smallest
difference was in Site 5 at 0.65 NTU. However, on Nov. 13, 2010 the biggest difference between
high tide and low tide measurements of turbidity was in Site 1 at 5.26 NTU; however, the
smallest difference remained in Site 5 at only 0.02 NTU. In contrast, the data from Oct. 02, 2010
shows that turbidity measurements were higher at high tide for Sites 1 and 5 while higher at low
tide in Site 3. Furthermore, the data set supports the Oct. 30, 2010 data which shows that
turbidity difference between tides was the highest in Site 3 at 8.16 NTU. However, the data
deviates from the other two because its smallest turbidity difference was in Site 1 at 3.56 NTU.
Overall, the data demonstrates that the tidal changes most affect the turbidity of Site 3 and least
affects Site 5.
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A high turbidity value indicates that the water is murky or brackish. Turbidity increases
during low tide for all sites because a lower water volume is disproportionately combined with
the suspended solids in the canal. In other words, a combination of less water and more sediment
leads to a high turbidity. Turbidity is especially high in Site 3 because of its location in the
middle of the estuary. The total amount of suspended solids from the Manoa-Palolo Valley in
Site 1 and the sea in Site 5 is heavily concentrated where they meet in the middle. Thus, turbidity
is at its highest in the center of the estuary. On the other hand, low turbidity value indicates that
the water is less murky and is closer to clear water. Turbidity is lowest in Site 5 because
sediment and suspended solids collected from the drainage in Site 1 is significantly less in Site 5
because it is farther away. Sea water carries fewer solids and therefore contributes to a low
turbidity value.
The turbidity levels also showed a recurrent pattern of inverse relationship with the level
of dissolved oxygen in the water. The data from Oct. 30, 2010 had the highest turbidity level at
6.88 NTU in Site 3 during low tide. At the same time, the dissolved oxygen concentration was at
its lowest at 50.75%. Likewise, in the Nov. 13, 2010 data, the highest turbidity level was at 5.38
NTU while the dissolved oxygen concentration was at its lowest at 56.71%. The relationship
between the two chemical properties shows that turbidity can impact the level of dissolved
oxygen in water in many ways. Turbidity is the measure of how much light is absorbed by the
particles in the water. When the sun’s rays are absorbed by the particles, energy is released as
heat. Hence, water with a high turbidity value can be heated more rapidly by the sun, which
causes the water to lose its ability to retain dissolved oxygen. This also gives insight to another
inverse relationship between water temperature and levels of dissolved oxygen. Furthermore, soil
particles and runoff from the Manoa-Palolo drainage may have carried with it nutrients that can
11
cause an outgrowth of algae. The decomposition of algae involves the consumption of significant
quantities of oxygen, thereby decreasing the overall level of dissolved oxygen in the water. Thus,
the algal blooms caused by high turbidity levels can cause a decrease in the amount of dissolved
oxygen. Finally, the runoff can also have carried microorganisms and particles that have a high
biological oxygen demand, which can again decrease the overall level of dissolved oxygen in the
water.
The low standard deviation values, ranging from approximately 0.25 to 1.0, for high tide
turbidity measurements on Oct. 30, 2010 and on Nov. 13, 2010 indicate that the values were very
consistent because they were relatively close to the average value. Hence, deviation from high
turbidity value in all sites especially Site 3 during low tide and deviation from a low turbidity
value in Site 5 may be due to the weather. The week of Nov. 13, 2010 included some rainy days,
which may have added to the runoff from Manoa-Palolo Valley, thereby contributing to the
amount of suspended solids in the estuary.
Total Dissolved Solids (TDS) in the estuary do not seem to show any dominant trend in
the data. Out of the days sampled, high tide shows a slightly higher concentration in some of the
sites on certain days, but the amount of average TDS during low tide was dramatically higher
than the high tide. The varying heights of the TDS on some days in some sites represent a lack
of correlation between TDS and tide. There is a drop of TDS in a site during high tide, but an
increase in tide also increases the TDS amount to levels similar to lower tide conditions. The
average amount of TDS measured in the estuary is 26.96 g/L.
The only conclusion drawn from the TDS data is the lack of correlation between tide and
TDS. Since the Ala Wai estuary contains a vast amount of sediments from fresh and salt-water
environments, the estuary tends to contain a constant amount of dissolved solids in the
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water. Water can only dissolve so much sediment before it enters a state of saturation, or
dissolved as much solid as the water can hold. Due to the lack of knowledge around the exact
nature of the solids, the saturation level of the estuary is unknown and could easily be the levels
measured. Whatever the height of the tide, the water in the estuary will maintain a constant
amount of dissolved solids by depositing sediments on the bed of the canal to adjust for oversaturation (more solids dissolved in the water than the water can hold) or dissolving more solids
to adjust for under-saturation (a state where water hold less dissolved solids than it can
hold). The feature of the estuary to maintain a constant amount of dissolved solids allows a
variety of plankton and other microorganisms to exist in its waters. For the first couple of
moments during the tide change, fresh water and salt-water pockets could indicate an amount of
dissolved sediments different from the actual amount, but overall the TDS is relatively
unaffected by the nature of the tides. Hence, the Ala Wai estuary maintains a constant TDS that
can dissolve in the water during any given tide.
The nitrate data consistently shows a higher concentration of nitric oxide during high tide
than during low tide. Besides showing a trend of higher amounts of nitrate during high tide, the
data shows some days where the amount of nitrate was significantly higher than on the other
days. Although the data for October 2, 2010 is significantly higher than the other days, the data
collected from the low tide is proportionally higher than the other days as well. There are a few
days where the low tide data drops significantly despite the proximity of the time the tides and
data were measured. The average nitrate concentration during the days of high tide is 5.723mg/L
deviating by 7.663 mg/L and the average concentration during low tide is 1.003 mg/L deviating
by 1.0705.
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The data shows a correlation between higher tides and higher amounts of nitric oxide in
the water of the estuary. Since the tide goes up due to the inflow of seawater into the estuary, the
increase of nitric oxide likely came from the main canal. The difference between the low tide
and high tide amount of nitrate is smaller in site 5 than site 1. The fresh water flowing from
upstream makes up a large amount of the estuary water during low tide and has small amounts of
organic matter. The salty seawater that flows in from the ocean during low tide carries
organisms, decaying organic matter, and human waste that contributes to the higher nitrate of the
estuary during high tide. The higher concentration of nitrate generally means a higher amount of
present organic substances are brought in during high tides and pushed out during low
tides. Hence, as an abundance of nitrate moves in the estuary during high tide, the estuary
naturally flushes back out that nitrate during low tide preventing the nitrate levels from becoming
too inhospitable for life.
In terms of dissolved oxygen, the low tide data shows a higher average percent across all
three zones than the low tide data. The data from October 2, 2010 shows the most dramatic
difference between the averages of dissolved oxygen. Due to the similarity of height of the tides
at the time of measuring the October 30, 2010 and November 13, 2010 data, the difference
between the high tide data than the low tide data is less noticeable, but the high tide still shows a
higher percent of dissolved oxygen. The percent of dissolved oxygen consistently maintains a
concentration of an average of 67.67% with a standard deviation of 29.94 during periods of high
tide and 49.91% deviating by 26.67 during low tide.
From the data, the Ala Wai estuary has a higher concentration of dissolved oxygen in the
high tide period than in the low tide period. By interpreting the dissolved oxygen data, the
concentration of dissolved carbon dioxide concludes to be higher during low tide and lower
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during high tide. Since the data shows the highest concentration difference occurring during
days when the difference between the high tide height and the low tide height was greatest, it can
be reasonably concluded that tide affects the temperature, sediments, or metabolic processes or
local organisms in a way that increases the concentration of carbon dioxide. A higher tide could
correlate with the time of most sun that allows photosynthetic organisms to photosynthesize
energy at a faster rate. An increase of cool, salty seawater into the estuary can decrease the
concentration of gases of the water and adversely selects the carbon dioxide produced closer to
the surface of the water to exit the water. The salinity of the water can inversely affect the
percentage of dissolved oxygen since the higher the salinity of the water, the lower the
percentage of dissolved oxygen. The data from the salinity measurements demonstrate an
inverse relationship with the concentration of oxygen. By maintaining an environment with a
high concentration of oxygen, the estuary can support a large amount of aerobic organisms when
they come in during high tide.
Error in this investigation may be due to faulty YSI readings, the weather, computer
errors, or human errors. Faulty YSI readings may have been due the inconsistent location at
which measurements were taken. Because the canal is a salt-wedge estuary, the salt water meets
the fresh water at different depths. Hence, at some points along the canal, the YSI may have been
gathering measurements from fresh water, salt water or both. The weather may have also played
a role, especially when the rain caused heavy runoff from the Manoa-Palolo Valley to enter the
canal. Also, in some areas the water was not deep enough for measurements to be taken at a
depth of one meter.
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V. Conclusions

Tide changes in the Ala Wai Canal do not affect either the pH or the total dissolved solids
of the water. This allows for a stable habitat and shows the high alkalinity of the Ala
Wai. Dissolved oxygen is higher at high tide than at low tide and allows aerobic
organisms to enter the estuary that can correlate to the increase of nitrates in the
water. Salinity is also greater at high tide due to the influx of seawater at that time and is
inversely related to dissolved oxygen levels. Turbidity increases at lower tides, making
the water more brackish than at high tides. The high turbidity levels during low tide
correlates to the low level of dissolved oxygen during low tide.

This experiment could be expanded by investigating these chemical properties at
different depths to see the effects of the change between salt and fresh water in the saltwedge estuary. Also, the animal life, or what is living in different sites at different tides
could be investigated to find the correlation between tide, chemicals, and life.

This investigation of chemical changes is important to life as it shows both how habitats
can stabilize themselves, such as with a high alkalinity so living organisms can be
constantly suited to their environment, and also how the chemicals can fluctuate to show
differing amounts of living organisms residing in the estuary at any particular tide.
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VI. Works Cited
Addy, Kelley , et al. 2003. pH and Alkalinity. Retrieved Oct. 30, 2010, from University
of Rhode Island Web site: http://www.uri.edu/ce/wq/ww/Publications/pH&alkalinity.pdf.
American Public Health Association. 1917. Standard methods for the examination of
water and sewage. Boston. *book
De Carlo EH, Spencer KJ. 1995. Records of lead and other heavy metal inputs to
sediments of the Ala Wai Canal, O’ahu, Hawai’i. Pac Sci 49(4): 471-491. *academic journal
FM River. (2004). Water quality. Retrieved October 30, 2010 from FM River site:
http://www.eerc.und.nodak.edu/watman/FMRiver/PPTV/factsheets.asp
Glenn, CR, McMurtry, GM. 1995. Scientific studies and history of the Ala Wai Canal, an
artificial tropical estuary in Honolulu. Pac Sci 49(4): 307-318. *academic journal
Hurst, Steve. (2002). Dissolved gases in sea water. Retrieved October 3, 2010 from
Geology 117: The Oceans site: http://ijolite.geology.uiuc.edu/02SprgClass/geo117/
lectures/Lect18.html.
Lau, Stephen L. and John Francis Mink. 2006. Hydrology of the Hawaiian Islands.
University of Hawai’i Press.
Mann, Kenneth and William Mitsch. 2011. Boundary Ecosystem. Retrieved January 09,
2011 from Encyclopedia Britannica Online: http://www.britannica.com/EBchecked/topic/
75627/boundary-ecosystem/70746/Boundary-systems-between-waters?anchor=ref588710.
Murphy, Sheila. (2007). BASIN: Information on Water Quality Parameters. Retrieved
Oct. 31, 2010 from City of Boulder / USGS Water Quality Monitoring
site:
http://bcn.boulder.co.us/basin/data/NEW/info/Turb.html
17
Myre, Elizabeth, and Ryan Shaw. (2006). The Turbidity Tube: Simple and Accurate
Measurement of Turbidity in the Field. Retrieved from Michigan Technological University
site: http://www.cee.mtu.edu/sustainable_engineering.
National Ocean Service. (2008). Salinity. Retrieved Oct. 31, 2010 from NOAA’s
National Ocean Service Education site: http://oceanservice.noaa.gov/education/kits/estuaries/
media/supp_estuar10c_salinity.html.
Richard Stockton College. (2010). Seawater Properties. Retrieved Oct. 31, 2010 from
The Richard Stockton College of New Jersey site: http://intraweb.stockton.edu/eyos/
page.cfm?siteID=105&pageID=65.
Sam Houston State University. (2010). Atmospheric chemistry glossary. Retrieved
October 3, 2010 from Sam Houston State University site: http://www.shsu.edu/~chemistry/
Glossary/lmn.html
Senese, Fred. (2010). What is pH? Retrieved Oct. 30, 2010, from General Chemistry
Online! site: http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/what-is-pH.shtml
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III. Data
Chemical Composition of Water in Sites 1, 3, and 5 of the Ala Wai Canal
Chemical Composition
pH
Salinity
Turbidity
Total Dissolved Solids (TDS)
Dissolved Nitrate Concentration
Dissolved Oxygen Concentration
Chemical Composition
pH
Salinity
Turbidity
Total Dissolved Solids (TDS)
Dissolved Nitrate Concentration
Dissolved Oxygen Concentration
Chemical Composition
pH
Salinity
Turbidity
Total Dissolved Solids (TDS)
Dissolved Nitrate Concentration
Dissolved Oxygen Concentration
October 02, 2010
High Tide (0.55 m)
Site 1
Site 3
Site 5
7.81
7.67
7.62
0.46
1.22
1.66
9
8.7
8.8
0.67
1.53
2.3
20.49
15.89
15.48
95.8
89.5
88.4
Low Tide (0.43 m)
Site 1
Site 3
Site 5
7.31
7.4
7.69
16.33
29.23
37.35
5.44
16.86
1.05
17.29
29.4
36.35
2.78
2.41
2.64
46.53
22
27.87
October 30, 2010
High Tide (0.58 – 0.61 m)
Site 1
Site 3
Site 5
7.7
7.5
7.36
35.29
35.14
35.15
4.92
3.74
2.93
34.8
34.66
34.67
11
1.9
0.71
60.64
68.88
80.39
Low Tide (0.55 – 0.43 m)
Site 1
Site 3
Site 5
7.6
7.55
7.57
30.67
35.33
34.20
6.88
6.39
3.58
30.68
34.84
33.83
0.23
0.22
0.18
50.75
62.24
81.35
November 13, 2010
High Tide (0.52m)
Site 1
Site 3
Site 5
4.92
7.15
7.29
0
35.06
35.19
-0.18
3.13
1.94
0
34.57
34.68
0
0.24
0.27
99.54
75.77
82.38
Low Tide (0.27 m)
Site 1
Site 3
Site 5
7.76
7.58
7.65
34.85
37.01
34.05
5.29
5.38
1.96
34.44
36.32
33.71
0.05
0.05
0.06
71.42
56.71
92.87
19
Tide Levels
Time
Tide (m)
October 02, 2010
0.46
0.55
0.61
0.64
0.61
0.52
0.43
0.431
October 30, 2010
0.58
0.61
0.55
0.43
0.31
November 13, 2010
0.52
0.49
0.46
0.37
0.27
0.18
9:00
10:00
11:00
12:00
1:00
2:00
3:00
4:00
10:00
11:00
12:00
1:00
2:00
10:00
11:00
12:00
1:00
2:00
3:00
Standard Deviation Values
pH
Salinity
Turbidity
TDS
Nitrate
Oxygen
S1
0.075
0.085
0.248
0.075
3.569
8.488
October 30, 2010
S2
S3
S4
0.012 0.012 0.008
0.108 0.049 0.132
0.339 0.138 0.446
0.094 0.045 0.117
0.025 0.035 0.010
2.191 2.618 0.844
S5
0.03
0.113
1.025
0.097
0.043
3.368
November 13, 2010
S1
S2
S3
S4
0.637
0.132 0.097 0.101
0
6.836 1.411 0.537
0.562
0.159 0.256 0.344
2.265e-19 6.378 1.251 0.474
0
0.144 0.022 0.027
0.138
3.066 2.303 20.56
S5
0.035
0.366
0.423
0.320
0.019
3.444
20
9
Comparing the pH Measurements of Water from the Ala Wai Canal during
High Tide and Low Tide
8
7
6
pH
5
High Tide
Low Tide
4
3
2
1
0
Site 1
Site 3
Site 5
Site 1
10/2/2010
40
Site 3
Site 5
10/30/2010
Site 1
Site 3
Site 5
11/13/2010
Comparing the Salinity Measurements of Water from the Ala Wai Canal during
High Tide and Low Tide
35
30
Salinity (ppt)
25
20
High Tide
Low Tide
15
10
5
0
Site 1
Site 3
10/21/2010
Site 5
Site 1
Site 3
10/30/2010
Site 5
Site 1
Site 3
11/13/2010
Site 5
21
Comparing the Turbidity Measurements of Water from the Ala Wai Canal during
High Tide and Low Tide
18
16
14
12
Turbidity (NTU)
10
High Tide
Low Tide
8
6
4
2
0
Site 1
-2
Site 3
Site 5
Site 1
10/2/2010
Site 3
Site 5
Site 1
10/30/2010
Site 3
Site 5
11/13/2010
Comparing the Total Dissolved Solids Measurements of Water from the Ala Wai Canal
during High Tide and Low Tide
40
35
30
TDS (g/L)
25
20
High Tide
Low Tide
15
10
5
0
Site 1
Site 3
10/2/2010
Site 5
Site 1
Site 3
10/30/2010
Site 5
Site 1
Site 3
11/13/2010
Site 5
22
Comparing the Dissolved Nitrate Measurements of Water from the Ala Wai Canal during
High Tide and Low Tide
25
20
NO3 (mg/L)
15
High Tide
Low Tide
10
5
0
Site 1
Site 3
Site 5
Site 1
10/2/2010
Site 3
Site 5
Site 1
10/30/2010
Site 3
Site 5
11/13/2010
Comparing the Dissolved Oxygen Measurements of Water from the Ala Wai Canal during
High Tide and Low Tide
120
100
DO (%)
80
60
High Tide
Low Tide
40
20
0
Site 1
Site 3
10/2/2010
Site 5
Site 1
Site 3
10/30/2010
Site 5
Site 1
Site 3
11/13/2010
Site 5