EFFECTS OF SURFACE RUNOFF AND WASTE DISCHARGE

INTO THE SOUTHERN SECTOR OF KANEOHE BAY:

JANUARY - APRIL 1968

by

Edison L. QuanReginald H. F. Young

Nathan C. Burbank, Jr.L. Stephen Lau

Technical Report No. 35

January 1970

The progr~ls and activities described herein were supported in part byfunds provided by the Department of Health of the state of Oregon andthe Federal Water Pollution Control Administration.

ABSTRACT

A study of the surface water quality in the southeastern portion

of Kaneohe Bay was undertaken between February and mid-April, 1968.

The aims of this project were to determine: (1) the effect of surface

runoff on water quality in the Bay, (2) the chemical and bacterial

content of wastewaters emerging from two sewage treatment plant out­

falls, and (3) whether the overall water quality standards were met.

High rainfall and subsequent high surface runoff introduce high

concentrations of nitrate-nitrogen and fecal streptococci into the

lower reaches of Keaahala and Kaneohe st~eams. High concentrations of

fecal streptococci also occur in waters overlying a clam bed during

high stream flows, suggesting that a potential public health hazard

may exist during the rainy period. High land runoff lowers the water

temperature by 2°C over dry weather flow and causes silt turbidity

along the nearshore waters in the Bay.

Phosphate-phosphorus concentrations in the Bay waters at the loca­

tion of waste discharge averaged 0.046 mg/l for the Kaneohe sewage treat­

ment plant and 0.033 mg/l for the Kaneohe Marine Corps Air Station sewage

treatment plant, exceeding the limit established for Class A waters by

0.02l and 0.U08 mg/l, respectively. Surface runoff is not a significant

contributor of phosphates into the Bay compared to the sewage waste

discharge.

In general, the dissolved oxygen content and pH adequately met the

water quality standards at all stations except for two low dissolved

oxygen readings in Keaahala Stream. Fpom mid-bay to the northePn

portion of the Bay, the parameters utilized indicated that the overall

water quality met the standards established for both Class AA and A

waters.

iii

CONTENTS

LIST OF FIGURES v

LIST OF TABLES vi

INTRODUCT ION 1

METHODS AND PROCEDURES 4

Sampling Stations 4Sampling Schedule 5Sampling Techniques 7Labora tory Analyses 9

RESULTS AND DISCUSSION 10

Hyd rolog i c Data 10Waste Discharge 12Parameters of Water Quality Studied 13

CONCLUS IONS 33

ACKNOWLEDGEMENTS 33

BIBLIOGRAPHY 35

APPENDIX 39

LIST OF FIGURES

Figure1

2

3

4

5

6

Reference Map Showing Location of Sampling Sites and Classi-fication of Surface Waters in Kaneohe Bay, Oahu 2Tidal Stages During Surveys Performed at Kaneohe Bay, Oahu,1968 6A J-Z Sampler Used at Kaneohe Bay, Oahu, to Collect Sub-surface Samples for Bacterial Analysis 8A Van Doren Sampler Used at Kaneohe Bay, Oahu, to CollectSubsurface Samples for Chemical Analyses 8Subdrainage Basins in the Southeastern Portion of KaneoheBay, Oahu, Showing Locations of Rainfall and StreamflowGaqing Stations llMean Daily Discharges from Kaneohe and KMCAS Sewage Treat­ment Plants into Kaneohe Bay, Oahu, 1968 ................•.. 14

v

7 Variations in Rainfall and Streamflow with Respect toNitrate-nitrogen, Fecal Streptococci, and Phosphate­phosphorus Concentrations in the Kaneohe Stream, off theStream Mouth, and from the Municipal Sewage Outfall, 1968 .. 15

8 Variations in Fecal Streptococci Concentrations at Station4 in Kaneohe Bay, Oahu, 1968 18

9 Variations in Fecal Streptococci Concentrations at Stations5 and 6 in Kaneohe Bay, Oahu, 1968 13

10 Variations in Fecal Streptococci Concentrations at Stations7 and 9 in Kaneohe Bay, Oahu, 1968 20

11 Variations in Fecal Streptococci Concentrations at Station8 in Kaneohe Bay, Oahu, 1968 20

12 Variations in Nitrate-nitrogen Concentrations at Stations5 and 6 in Kaneohe Bay, Oahu, 1968 23

13 Variations in Nitrate-nitrogen Concentrations at Stations7,9, and 8 in Kaneohe Bay, Oahu, 1968 23

14 Variations in Phosphate-phosphorus Concentrations at Stations5 and 6 in Kaneohe Bay, Oahu, 1968 24

15 Variations in Phosphate-phosphorus Concentrations at Stations7 and 9 in Kaneohe Bay, Oahu, 1968 24

16 Variations in Phosphate-phosphorus Concentrations at Station8 in Kaneohe Bay, Oahu, 1968 24

17 Ch10rinity Variations at Stations 1, ?, and 3 in Kaneohe Bayin Kaneohe Bay, Oahu, 1968 27

18 Ch10rinity Variations at Stations 5 and 6 in Kaneohe Bay,Oahu, 1968 27

19 Ch10rinity Variations at Stations 7,8, and 9 with Respectto Rainfall Recorded at Coconut Island in Kaneohe Bay,Oahu, 1968 28

LIST OF TABLES

Table1 Classification of Kaneohe Bay Waters by Uses and Specific

Standards 32 pH Range at Each Sampling Station in the Southern Portion

of Kaneohe Bay, Oahu 31

vi

INTRODUCTION

Surveys were conducted on Kaneohe Bay during a ten-week period

between February and mid-April 1968 to determine:

1. The effects of surface runoff on the physical, chemical, andbacterial quality of drainage waters in the southern portionof Kaneohe Bay,

2. The chemical and bacterial quality at two sewage treatmentplant outfalls located in the southeastern portion of KaneoheBay, and

3. Whether the overall water quality standards set forth by theState Health Department were met.

Because very few sanitary surveys have been performed in the streams

and nearshore waters of Hawaii, it was also the aim of this short-term

project to provide recommendations for future water-pollution studies.

A la-foot fiberglass boat powered by a 6-horsepower outboard motor

was used to collect water samples and to measure certain parameters in

situ at nine established sampling sites. Physical parameters such as

temperature and water transparency were observed in the field. Samples

collected for dissolved oxygen content were pretreated in the field and

final determinations were performed in the laboratory.

Two sets of water samples for chemical and bacterial analyses were

collected from each station except from the waters overlying a clam bed

where only a sample for bacterial analysis was collected. The chemical

parameters determined in the laboratory included nitrate-nitrogen, solu­

ble pho~phate-phosphorus, chlorinity, and pH. The fecal streptoccal

group of bacteria was analyzed by using the membrane filter technique.

The hydrologic data which included rainfall and streamflow were

obtained through the courtesy of the U. S. Weather Bureau and the U. S.

Geological Survey, respectively. Effluent samples were obtained from

the Kaneohe Sewage Treatment Plant and the Kaneohe Marine Corps Air

Station Sewage Treatment Plant through the cooperation of the Sewers

Division of the City and County of Honolulu and the Naval Facilities

Engineering Command, Department of the Navy, respectively.

The Department of Health, State of Hawaii, has defined and classi­

fied the nearshore and offshore waters according to water uses with

specific standards according to multiple uses. Figure 1 shows the

boundaries of the waters classified and Table 1 summarizes the specific

standards according to classifications. Of the 10 specific standards

""

FIGURE 1. REFERENCE MAP SHOWING LOCATION OF SAMPLING SITES ANDCLASSIFICATION OF SURFACe WATERS IN KANEOHE BAY7 OAHU.

3

TABLE 1. CLASSIFICATION OF KANEOHE BAY WATERSBY USES AND SPECIFIC STANDARDS

SPECIFIC STANDARDSTOTAL P, TOTAL N, D.O.,

CLASS USES MG/L MG/L MG/L TEMPERATURE TURBIDITY

AA OCEANOGRAPHIC RESEARCH 0.020 0.10 &.0 NOT TO CHANGE SECCHI DISC ORPROPAGATION OF SHELL- MJRE THAN 1. 5°F EQUIVALENT ASFISH AND MARINE LIFE FRO'1 NATURAL "EXTINCTIONCONSERVATION OF CORAL CONDITIONS COEFFICIENT"REEFS AND WILDERNESS SHALL NOT BEAREAS AND ESTHETIC ALTERED FRO'1ENJOYMENT NATURAL

CONDITI ONS MJRETHAN: 5%

A RECREATIONAL, INCLUDING 0.025 0.015 5.0 SAME 10%FISHING, SWIMMING,BATHING, AND OTHERWATER CONTACT SPORTSAND ESTHETIC ENJOYMENT

B SMALL BOAT HARBORS 0.030 0.20 4.5 SAME 20%CQI1MERCIALSHIPPING AND INDUSTRIALBAIT FISHINGESTHETIC ENJOYMENT

TOTALBACTERIA, DISSOLVED

CLASS PH-UNITS COLIFORM/100 ML SOLIDS, MG/L SALINITY RADIONUCLIDES

AA 8.0-8.5 MEDIAN 70 28.00 FRESH WATER INFLUX 1/30THNOT TO CAUSE OF THE MPC

230 ANYTIME PERMANENT CHANGES IN w

ISOHALINE PATTERNSBY MORE THAN 10%

A 7.0-8.5 MEDIAN 1,000 NON-APPLI CABLE NON-APPLI CABLE SAME AS ABOVE10% 2,400

FECAL COLI FORMSA. 200 FOR 30-

DAY PERIODB. 10% 400

B 7.0-8.5 FECAL COLI FORMS NON-APPLI CABLE NON-APPLI CABLE SAME AS ABOVEA. 400 FOR 30-

DAY PERIODB. 10% 1,000

4

applicable to bay waters, this investigation examined 6 of the para­

meters. Although the fecal streptococcal group of bacteria was ana­

lyzed, it was not one of the choice indicator organisms approved by the

Federal Water Pollution Control Administration for water quality in any

of the state's waters. The coliform group of bacteria which has been

adopted for over half a century as an indicator organism was continued

as their parameter of fecal contamination. The other parameters which

were not measured in the present study included dissolved solids, ap­

plicable to Class AA waters only, and background radiation.

METHODS AND PROCEDURES

Sampling Stations

The sampling sites are described below and numbered on the refer­

ence map (Figure 1) to show the relative position of the stations. Each

of the nine sites can be determined readily by prominent features in the

Bay or by sighting two or three landmarks. Hereafter, all sampling sta­

tions will correspond to the site descriptions presented below:

Station Number

1. Kaneohe Stream

2. Kaneohe Streammouth

3. Kaneohe sewagetreatment plantoutfall

4. Clam bed

5. Keaahala Stream

Description

This station is located approximatelyvSC yards upstream from the mouth of thestream.

This station is approximately 100 yardsnorth of the stream mouth. It is quiteshallow, generally less than three feetdeep.

This station IS marked with two one­gallon clorox containers on either sideof the outfall plume. It is approximately650 yards north of the eastern shore ofKaneohe Stream mouth in line with the endof the pier west of Kaneohe Stream.

The shallow area to the west of KaneoheStream mouth contains a clam bed. Thesampling site is marked by a pilingapproximately 200 yards northwest ofKaneohe Stream mouth. Samples were col­lected from this station for bacteriolog­ical analysis only.

This station is located in a pool areaapproximately 150 feet upstream from theKaneohe Marina boat launch.

Station Number

6. Keaahala Streammouth

7. East ofCoconut Island

8. Kaneohe MarineCorps AirStation (KMCAS)sewage treatmentoutfall

9. Buoy '27'

5

Description

This station is located in the bayapproximately 150 yards northeast of thestream mouth.

The thTee landmarks used to identify this.station are:

1. the southeastern tip of Coconut Island

2. the mouth of Kaneohe Stream

3. the second hanger counting from the eastat the Kaneohe Marine Corps Air Station.

The outfall plume can be identified bythese landmarks:

1. the end of the boat pier of KMCAS

2. the third piling in the Bay due south ofthe first piling west of the sewagetreatment plant.

3. the alignment of the end of the boatpier and third piling in the Bay so thatthe outfall plume is perpendicular tothe third piling along the beach.

This is directly north of Coconut Islandand it marks the seaweed side of the shipchannel.

Sampling Schedule

Water samples were collected from Kaneohe and Keaahala streams and

from the selected sites in the southeastern portion of the bay for

chemical and bacteriological analyses. Of the ten surveys conducted

between February and mid-April, five were made on a Saturday, one on a

Sunday, and four during a weekday. All of the surveys were made between

the hours of 9 A.M. to 12 P.M. with the exception of one survey which

was made between 7 to 9:30 A.M. The surveys were scheduled during the

morning hours for several reasons: (1) the bay was generally calm during

the morning hours, (2) the peak discharge from the sewage treatment plant

occurred between 9-10 A.M., and (3) the time lag between sample collection

and bacteriological analysis could be kept to a minimum.

Figure 2 shows the survey times in relation to tidal variations in

Kaneohe Bay. The surveys between February 10 to 26 were conducted between

the high low and low high tides. Between March 31 and April 4, the sur-

6

2

ot-----

2

o ~----Al------....FEB. 10 MAR. 31

-I -I

2

o

2

o~--

0 0

FEB. 24 APR. 4-I -I

....W 3 3WL1..~ 2 2

W<.!)<X 1....00

...J0 0

<X MAR. 9 APR.S0-1 -I....

3 3

2 2

MAR. 23-I

APR. II-I

22

0 0

MAR. 2S APR. 13-I -I

I ,0 0 0 0 0 0 0 0 0 80 ~ 0 0 0 0 0 0., 0 ., ., ID !!!

.,N 0 ~ !!! N N 0 ~ N

T I M E

FIGURE 2. TIDAL STAGES DURING SURVEYS PERFORMEDAT KANEOHE BAY, OAHU, 1968.

7

veys were made during low tide and on April 6, it was during the ebb

flow of a low high tide. On April 11 and 13, the surveys were made

immediately following low tide on the incoming high tide.

Hydrological data were obtained from both the U. S. Weather

Bureau and the U. S. Geological Survey. The Weather Bureau generally

measured rainfall daily at the gaging stations. The U. S. Geological

Survey maintained a streamflow and rainfall gaging station near the

mouth of Kamooalii Stream, a tributary to Kaneohe Stream.

Waste discharge flow data from the Kaneohe Municipal Sewage Treat­

ment Plant were provided by the Division of Sewers, City and County of

Honolulu. Similarly, the data from the Kaneohe Marine Corps Air Sta­

tion was provided by the Sanitation Division of the U. S. Navy.

Sampling Techniques

All of the surveys were conducted from a 10-foot fiberglass boat

powered by a six-horsepower outboard motor. The time required for each

survey ranged from 2.5 to 3.5 hours depending upon the weather and water

conditions.

Water transparency was measured with a l2-inch (ca. 30 ~m.) Secchi

d~c. The surface of the metal disc was painted white and a lead weight

was attached to the underside of the disc. The disc was lowered to a

depth at which the white surface was no longer apparent and the depth at

which the disc disappeared was measured to the nearest 0.5 meters.

A J-Z Sampler was used to collect water samples from one meter

below the water surface for bacterial analysis of fecal streptococci.

The sampler (Figure 3) consists of a metal frame equipped with a break­

ing device for the glass tube and a clamp to securely hold a sterile

300-ml bottle. The sample was stored in an ice chest containing canned

ice and returned to the laboratory for analysis.

Water samples were collected with a 2-liter Van Doren sampler. An

l8-inch rubber tube was attached to the lower spigot of the Van Doren

sampler to collect a sample for dissolved oxygen determinations. The

end of thf? tub: 'lg was placed on the bottom of a 300-ml BOD bottle. Be­

tween 500 to 600 ml of water were allowed to overflow from the bottle

before a sample was collected for pretreatment. This procedure was fol-

FIGURE 3. A J-Z SAMPLER USED AT KANEOHE BAY7

OAHU7 TO COLLECT SUBSURFACE SAM­PLES FOR BACTERIAL ANALYSIS.

FIGURE 4. A VAN DOREN SAMPLER USED AT KANEOHEBAY 7 OAHU 7 TO COLLECT SUBSURFACESAMPLES FOR CHEMICAL ANALYSES.

00

9

lowed to minimize the possibility of measuring oxygen entrained in the

water during the bottle filling process. The remainder of the water

in the sampler was transferred to a I-liter polyethylene bottle which

was stored in an ice chest.

Dissolved oxygen samples were fixed in the field immediately after

collection and brought to the laboratory for titration. The azide mod­

ification of the iodometric method was utilized as outlined in Standard

Methods (1965).

Water temperature was measured by immersing the bulb end of a

centigrade thermometer below the water surface in the Van Doren Sampler.

The temperature was read to the nearest 0.5 degree while the thermometer

was immersed.

Laboratory Analyses

The procedure to test the presence of the fecal streptococcal

group as outlined in Standard Methods (1965) was used although the method

is specified, as being tentative.

Nitrate-nitrogen was determined by the procedure outlined by Kahn

and Brezenski (1967) using the brucine method described by Jenkins and

Medsker (1964) with modifications to give more consistent analytical

calibration curves which follow the Beer-Lambert Law from 0 to 0.6 mg of

nitrate-nitrogen per liter.

Orthophosphate or reactive phosphorus was determined by the pro­

cedure of Murphy and Riley (1962) as outlined by Strickland and Parsons

(1965). Prior to analysis, all water samples were filtered through a

membrane filter with 0.45-m~ pore size to remove silt and biological

detritus.

Chlorinity determinations were made by titration using the low

precision method outlined by Strickland and Parsons (1965).

Strickland and Parsons (1965) recommended that a large volume of

sea water be collected from below 50 meters in the open ocean with a

chlorinity near to 18 parts per thousand (0/00) to serve as a standard,

however, a synthetic sea water was utilized containing the two principal

halogen~, chloride and bromide, with a chlorinity of 18.11 0/00 checked

with a Hytech Portable Laboratory Salinometer, Model 6210, at the U. S.

10

Bureau of Commercial Fisheries Laboratory.

The pH of the collected water samples was measured electrometrically

by using a Beckman pH meter.

RESULTS AND DISCUSSION

Hydrologic Data

Rainfall and streamflow are closely related in the Kaneohe Bay

drainage basin. The rainfall distribution increases rapidly from the

Coconut Island area to the Koolau mountain area. This is a relatively

short distance. Also centered around the southern portion of the bay

drainage basin is the Kaneohe urban area.

RAINFALL. The U. S. Weather Bureau maintains four rain gaging stations

within the drainage basins of Kaneohe and Keaahala streams while the

U. S. Geological Survey maintains one. Figure 5 shows the relative

location of each gaging station.

The stations range in elevation from near sea level (Coconut

Island) to approximately 400 feet (Pali Golf Course). Because of the

orographic rainfall pattern along the windward coast, precipitation

increases directly with elevation. During the months of February,

March, and April, the rainfall measured at Coconut Island were 2.26,

10.06, and 5.90 inches, respectively. For the same period, the rain­

fall at Luluku gaging station (elevation 250 feet) was, respectively,

5.0, 24.6, and 10.8 inches. The rainfall reported at Kaneohe mauka

(inland or towards the mountain) gaging site (elevation 200 feet) was

4.72, 17.62, and 7.41 inches, respectively, while at the Pali Golf Course

it was 4.26, 18.57, and 10.10 inches, respectively.

Of the ten surveys performed, the highest rainfall occurred on

March 23 with 0.24 inches recorded at Coconut Island between 8 A.M. on

March 23 to 8 A.M. on March 24. For the same period, the Luluku gage

recorded 1.8 inches. The highest 24-hour rainfall occurred on March

13, with 2.31 and 10.2 inches measured at the Coconut Island and Luluku

gages, respectiJely.

The median annual rainfall over the southeastern portion of the

bay area ranges from 40 inches at the northern portion of the Bay to

KANEOHE8 A r

FIGURE 5. SUBDRAINAGE BASINS IN THE SOUTHEASTERN PORTIONOF KANEOHE BAY, OAHU, SHOWING LOCATIONS OFRAINFALL AND STREAMFLOW GAGING STATIONS.

11

12

50 inches at the southern portion of the Bay. The median annual rain­

fallon top of the Koolau Range within this drainage area is 75 inches.

During the survey period, a total of 18.2 inches of rainfall was re­

corded at Coconut Island, and 46.4 inches at the Luluku gaging station,

located near the foot of the Koolau Range.

STREAMFLOW. The only streamflow gaging station within the two stream

drainage basins is located near the mouth of Kamooalii Stream, a tribu­

tary to Kaneohe Stream. The gage is located approximately one mile

above the mouth of Kaneohe Stream at an elevation of 38.8 feet.

The average daily streamflow during the 10 surveys ranged from

a low of 14.4 to a high of 43.0 cubic feet per second (cfs). The low

flow occurred on the March 9 survey and the high flow, on the March 23

survey. In general, the streamflows in February and early March were

low. A peak, recorded on March 23, gradually declined until approximate­

ly the February level was reached in April.

Overall, the streamflow pattern followed the rainfall pattern

during the survey period. Although all the streamflow data from Kamoo­

alii Stream was not tabulated for 1968, the runoff remains high for

only a short period following a heavy rainfall of short duration.

Many reaches of the streams and canals within the southeastern

portion of the Kaneohe Bay drainage basin are lined to prevent scouring

action on the stream bed and erosion of the stream banks following heavy

rainfall which at times produce flash floods. With urban development

continuing rapidly within the drainage basin, the amount of land area

available to absorb rainfall and the cover of vegetation to retard

surface runoff will become less in the coming years. Therefore, stream­

flows and the associated silt load and other contaminants can be expected

to increase.

Waste Discharge

During the survey period, the Kaneohe municipal sewage treatment

plant discharged between 1.8 to 2.3 MGD of sewage effluent, an average

of 2.1 MGD, into the southern portion of the Ba} (Figure 6). This is

a secondary treatment plant with a biofiltration process that usually

provides 85 percent biochemical oxygen demand (BOD) removal. During and

13

following the survey period, an expansion program of the treatment

plant was underway since the design hydraulic capacity of the plant

was already exceeded. The flow through this unit operation was by­

passed on several occasions because the distributor arms of the trick­

ling filters required cleaning. This caused a surge of 5 MGD through

the chlorination unit for a 10 to 15 minute period. Samples were not

collected during these peak flows ..

The Kaneohe Marine Corps Air Station discharged between 0.7 to

1.0 MGD of effluent with an average of 0.8 MGD into the Bay during the

survey period (Figure 6). This is a primary treatment plant, a type

of plant that usually provides approximately 30 to 35-percent BOD removal.

On the first four surveys, the samples were not directly collected from

the outfall plumes; therefore, the data is not indicative of the quality

of plant effluent with minimum mixing and dilution.

The personnel of the Hawaii Institute of Marine Biology located on

Coconut Island ranges between 25 to 50. The sewage from this small popu­

lation is discharged raw into the ship's channel area at the northeast

section of the fringing reef. This raw waste discharge was not assessed

because most of the surveys were conducted on a Saturday or Sunday when

activities on the Island were at a minimum. Although four surveys were

performed on a Tuesday and three on a Thursday, only one attempt was

made to observe the outfall area. The location of the outfall at the

edge of the fringing reef would make any study by boat on the waste con­

tribution difficult because of the wave action in that area. Furthermore,

the small volume of sewage contributed from the island population should

be diluted rapidly in the channel; consequently, it is doubtful that

significant water quality effects could be detected.

Parameters of Water Quality Studied

FECAL STREPTOCOCCI. Because warm-blooded animals are the only species

known to harbor fecal streptococci, this group of microorganisms is a

useful indicator of fecal contamination in waterways. It is especially

useful as an indicator in estuarine and marine waters because of the

organisms' ability to tolerate a higher saline environment than the

coliform group of bacteria which has been so popular for the past fifty

years as the bacterial indicator of water quality.

14

3.0STPg KANEOHE (3)

-KMCAS (8)

0 2.5(.!)

~

..w~ 20<t:I:Ueno~ 1.5<toW

~ 1.0 ~ ~w ..... "e-......... ,~ '-....-.--.--.. ...

0.5

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

0.0 '--_.....L----L_.....L----L_~___J_~___J_.....L...___I

FIGURE 6. MEAN DAILY DISCHARGES FROM KANEOHEAND KMCAS SEWAGE TREATMENT PLANTSINTO KANEOHE BAY, OAHU, 1968.

.ii

14.00

13.00 , .LULUKU GAGEELEVATION=250 FT.

~OOr II KANEOHE STREAMORAINAGE

11.00

10.00

9.00

f:l 8.00x~.; 7.00...J

5~ 6.00

5.00

4.00

3.00

2.00

1.00

0.00

IMEAN OAILY FLOW

45.00'KAMOOALII STREAM

40.

'" MOOIL0

•~30.00:::Ei:5~"'2500

20.00

15.00

0.00. QKANEOHE STREAM (tJ

-100 YOs. FROM KANEOHE STR. NO (2J0.60 t-6KANEOHE ~ STP I!JJ

I,0~5t- II

, I

I \0.50 t- I I

I \0.45 , ,

I-: I \~ 0.40 I \

Z I \

~ 0.35 I ...'"I \

!:: \Of 030 QI\

~ r ,10.25

, -I, \ II \020 I \ I

I \,

0.15 l- I \ I\ I

I \ I0.10 I-

.JA \ I0.05 A

,~

000 QKANEOHE STREAM OJ• -100 YOS. FROM KANEOHE STR. NO 12J

10 6KANEOHE STP OUTFALL (!JJ

i§ 10'

Iu ._.

,I

[

e KANEOHE STREAM (I)

e,ooyDS. FROM KANEOHE STH. Ma (2)

aKANEOHE STP I!I)

~~... 10'

Ie!

to"

I,,,I,,

\5j\f;\ I\ I\ I

~

J4.0~

3.0 iitg

2.0 ...

~

10·. I '" I J • , I , I

10249232&31461113FEB. MARCH APRIL

:;;...e<Ii 10"::>

II

i~ll. 10'·

FIGURE 7. VARIATIONS IN RAINFALL AND STREAMFLOW WITH RESPECT TO NITRATE-NITROGEN,FECAL STREPTOCOCCI, AND PHOSPHATE-PHOSPHORUS CONCENTRATIONS IN THE KANEOHESTREAM, OFF THE STREAM MOUTH, AND FROM THE MUNICIPAL SEWAGE OUTFALL, 1968.

17

The concentration of fecal streptococcal bacteria observed in the

streams (Stations 1 and 5) and nearshore stations (2, 4, 6) fluctuated

according to rainfall (Figures 7, 8, and 9) streamflow (Figure 7) and

ch10rini ty (see "Ch1orinity" on p. 28 for a discussion). During the high

rainfall and the subsequent high streamflow observed on March 23, the

bacterial population also reached a high density. This phenomenon

indicates that the high surface runoff was transporting an unusually high

concentration of streptococci into the Bay. Since many other studies have

shown that most warm-blooded animals harbor this group of organisms, part

of the high concentration can be attributed to the domestic animal popu­

lation in the urban area. Another possible source of the microorganism

may be attributed to overflow from the cesspools within Kaneohe since

that community is not yet completely sewered.

The bacterial density observed at Station 5 (Keaahala Stream)

generally was higher than that observed at Station 1 (Kaneohe Stream)

(Figures 7 and 9). This may possibly be explained by the differences

in size of the drainage basins and systems. In comparison, the Kamooalii­

Kaneohe drainage basin is approximately 4.38 square miles and the Keaaha­

la basin is 0.59 square miles. Through visual inspection, the community

within the Kamooalii-Kaneohe Stream drainage basin is much more developed

than that within the Keaahala drainage basin. It would appear that the

dilution factor may be the reason for the overall lower streptococci

densities observed in Kaneohe Stream.

At Station 4 (Figure 8) where only bacterial samples were collected

from the waters overlying a clam bed, the streptococci density followed the

same trend as the streamflow and Stations 1 and 2 (Figure 7). The high pop­

ulations observed at Station 4, especially following high rainfall and

streamflow suggest a possible health hazard during the active clam digging

season between November and February.

At the Kaneohe sewage treatment plant outfall, the streptococci

concentration was relatively low with the exception of two samples which

yielded 230 and 312 organisms per 100 ml (Figure 7). Of the ten samples

collected, six yielded concentrations of less than 16 per 100 mI. During

each of the surveys, the effluent discharge rate was on the average

approximately 0.5 to 1.6 million gallons per day (MGD) above the average

daily discharge. There is, however, no well-defined correlation between

104

CLAM BED10

4

Q KEAAHALA STR (5)

• /00 YDS FROM KEAAHALA STR MQ (6)

.....00

.,

I,, v:/\ I, \ I, \ II \ II \ /I \ /I \/I ,

I,I

•

~I~uuou~a..lJJ0::l­V)

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

10°' I I ' I I I , , I ,

..J

~IdlJJLL

Eoldo"-V)

~V)

Z<fC>0::o

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

10° , I I .. I I I I I , I

102

E 103

oo"-V)

~V)

Z<fC>0::o

uuouoIi:lJJ0::l­V)

<1. 10'ulJJLL

FIGURE 8. VARIATIONS IN FECAL STREPTOCOCCICONCENTRATIONS AT STATION 4IN KANEOHE BAY, OAHU, 1968.

FIGURE 9. VARIATIONS IN FECAL STREPTOCOCCICONCENTRATIONS AT STATIONS 5 AND 6IN KANEOHE BAY, OAHU, 1968.

19

rate of discharge and bacterial count. On April 6, the discharge rate

was 3.7 MGD and the bacterial density was 14 per 100 mI. However, on

April 13, when the discharge rate was 3.5 MGD, the count was 310 organisms

per 100 mI. The fluctuation of the bacterial population may be more

closely related to chlorination dosage and contact time.

The bacterial populations at Stations 2 and 6, immediately beyond

the mouth of the two streams, yielded lower population densities than

the streams with the exception of three samples obtained from Station 2

on March 31 and April 4 and 6, which may be attributed to the lower

chlorinity observed on those dates. Gundersen and Stroup (1967) collected

four sample~ during August 1967 in the vicinity between Stations 3 and

6 and found 60 and 4 streptococci per 100 ml in two samples. Iha (1960)

determined the reduction in coliform and enterococci in Kailua Bay,

Oahu by releasing raw sewage marked with fluorescein dye and tagged

with l4C in the surface water. He sampled the sea water periodically

and noted that a 99.99 percent mortality was observed within 30 minutes

of exposure in the sea. Hence, he concluded that bactericidal action of

sea ~1ater was the most important process in the reduction of sewage

bacteria.

A small population of streptococci was observed at Station 7 (Figure

10) during the survey period. Out of four surveys at this approximate

location, Gundersen and Stroup (1967) observed a population density of

12 organisms per 100 mI. Bathen (1968) stated that this particular area

was an eddy for nearshore waters. Therefore, some of the viable bacte­

ria were probably transported to this station site by the circulating

current. Slanetz, et al. (1965), in studying the survival of fecal strep­

tococci in sea water by placing sewage effluent in dialysing cellophane

bags suspended in the Bay, observed that complete die-off occurred within

7-11 days.

Only on three occasions, March 26, April 11, and 13, were samples

collected directly from the KMCAS outfall plume (Figure 11). Of the three

samples obtained, two yielded population densities of 1,140 and 1,500

organisms per 100 mI. It is believed that the concentration of bacterial

density recovered in the laboratory is influenced by a number of factors

from the effluent plumes. One important factor may be the residual

chlorine present in the sample. The residual chlorine produces a bacte-

102

EAST OF COCONUT /S (7)

104

KMCAS STPOUTFALL AREA

No

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

10°' I I ' I , , , , , ,

E0103

o"-en~enZ<l(!)a::o

...:102

uuoug0..lJJa::t­en

...J<l101

~IL.

BUOY '27' (9)

100 I I WI' I W 1« I I)' !

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

• °U 10 I I I IU W , Io I I I , I \ !

Ug0..lJJa::t­en

...J<lUlJJ 10'IL.

E~ 10

1

"­en~enZ<l(!)a::o

FIGURE 10. VARIATIONS IN FECAL STREPTOCOCCICONCENTRATIONS AT STATIONS 7 AND 9IN KANEOHE BAY, OAHU, 1968.

FIGURE 11. VARIATIONS IN FECAL STREPTOCOCCICONCENTRATIONS AT STATION 8IN KANEOHE BAY, OAHU, 1968.

21

ricidal action in the time between the collection and processing of the

sample. It is advisable to add sodium thiosulfate to sample bottles

used to collect effluent samples to nullify the action of chlorine in future

surveys of this nature.

Very few streptococci were encountered in 5 of the 10 samples ob­

tained at Station 9 near the ship's channel (Figure 12). Gundersen and

Stroup (1967) did not sample in the immediate area but they observed 2

organisms per 100 ml at a station to the right of this station. Bathen

(1968) noted that most of the surface water leaves the southwest basin

through the channel area near Buoy 27 which would account for the detec­

tion of some streptococci at this station.

NITRATES. The nitrate data indicate that the greatest source of this

nutrient is from land runoff, especially following a heavy rain and high

streamflow (Figures 7 and 12). In Kaneohe Stream (Station 1) the high

concentrations of nitrates show an inverse relationship with the chlori­

nity content, indicating that nitrates are associated with fresh-water

sources. During the high rainfall on March 23, a maximum concentration

of 0.60 mg/l was observed at Station 2. Similarly, on the same date,

Keaahala Stream (Station 5) yielded a concentration of 0.45 mg/l -- the

maximum observed out of eigh~ samples.

Weibel, et aZ. (1966) measured 0.50 mg/l of nitrate-nitrogen in

an urban storm-water runoff during a storm in 1965 from a 27-acre resi­

dential, light commercial area in Cincinnati, Ohio. In an earlier study

(Weibel, et aZ., 1964) in the same area, they found between 0.1 to 1.5

mg/l of N03-N resulting from urban land runoff over a nine-month period.

Sylvester (1960) found up to 2.80 mg/l of N03-N in storm-water samples

from Seattle street gutters between 1959 and 1960.

The effluent samples from both sewage treatment plants (Stations 3

and 8) contained low concentrations of N03-N with the exception of one

sample collected from Station 3 on March 23 which contained 0.1 mg/l.

Standard Methods (1965) states that effluent from trickling filter

treatment systems may contain from 0 to 50 mg/l nitrate-nitrogen, de­

pending upon the total nitrogen content of the influent, the degree of

loading, and the temperature of the sewage. Without the benefit of

parallel samples of collected effluent prior to its discharge through

22

the outfall, it is difficult to evaluate the role of dilution in the

discharge of sewage through multiple outlets.

The nitrate-nitrogen content in the offshore waters (Stations 7

and 9) generally were consistently low, usually less than 0.03 mg/l

(Figure 13). However, the concentrations of nitrate-nitrogen at the

lower reaches of the streams and at the nearshore areas immediately

beyond the stream mouths approached the upper limit or exceeded the

water quality standards for all nitrogen forms for Class A waters

whenever the stream runoff was high. Nitrogen expressed as nitrates

present in the sewage outfall plumes and offshore areas adequately met

the standards for Class A and AA waters.

PHOSPHATES. The phosphate-phosphorus concentration generally was low

at all sampling sites except at sewage outfall Station 3 and occasionally

at Station 8 (Figures 7, 14, 15, and 16). High rainfall and streamflow

did not appear to be a significant contributor of this nutrient to the

Bay. The high concentrations observed on several occasions at Stations

1 and 5, Kaneohe and Keaahala streams, respectively, originated from

the Kaneohe sewage treatment system. On both April 6 and 11, the

soluble phosphate concentrations were 0.023 and 0.014 mg/l when the

chlorinities were, respectively, 16.35 and 14.90 %0. Bathen (1968)

suggested that the high concentrations in the two streams are generally

due to the intrusion of surface water from around the Kaneohe outfall

during the incoming tide or during strong trade winds.

During the survey period, the average concentration of phosphate­

phosphorus from the Kaneohe sewage outfall was 0.046 mg/l as compared

to the 0.0443 mg/l average given by Bathen (1968) for a l3-month period.

This concentration is two times the upper limit of 0.02 mg/l for Class

A waters. In comparing the sewage treatment plant discharge rate with

the concentrations of phosphates, it is evident that the concentration

will be exceeded when the discharge rate exceeds 3.0 MGD.

A total of three samples were collected from the KMCAS outfall

plume on March 26 and April 11 and 13. The mean phosphate concentration

from these saml les was 0.033 mg/l. However, of the three values used

to compute the average concentration, only one exceeded the limit for

Class A waters. Bathen (1968) found a mean value of 1.073 ~g-at P/l

(0.0333 mg/l) over a l3-month period at this station.

0.55, Q KEAAHALA STR (5)

• /00 Y05. FROM KEAAHALA STR (6)

0.10 EAST OF COCONUT /5. (7)

0.50

BUOY 27 (9)

KMCAS STP AREA (8)

0.05

0.00' I I I , " , I , I ,

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

_ 0.00' , , I I I I , , ,

~O.IOE

0.05

~

ZWC)

~ 0.05~

zI

WI-~ 0.00 I , I , I - I I I I I

t: 0.10z

~\

0.15

0.10

0.05

0.40

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

0.00' , " I I I - I I

0.45

-"'­enE~ 0.35

zw<!)00.30a:::~

zI 0.25

w~~ 0.20z

FIGURE 12. VARIATIONS IN NITRATE-NITROGENCONCENTRATIONS AT STATIONS 5 AND6 IN KANEOHE BAY7 OAHU7 1968.

FIGURE 13. VARIATIONS IN NITRATE-NITROGENCONCENTRATIONS AT STATIONS 77 97AND 8 IN KANEOHE BAY7 OAHU7 1968.

NVI

24

10"'

gKEAAHALA STR (5)

e/OO YOS FROM KEAAHALA STR Mo. (6)

i\ ~I 'I. / \I" I \I \ J \I -.-... \I

~I

/---.4

10"' l..---"---'---'--'--'--'---'------'----..............10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

FIGURE 14. VARIATIONS IN PHOSPHATE-PHOSPHORUSCONCENTRATIONS AT STATIONS 5 AND 6IN KANEOHE BAY? OAHU? 1968.

gEAST OF COCONUT ISLAND (7)

• BUOY '27' (sn.~ 102

a::o:I:11.CJloit,I '"W E!i:I:11.CJlj! ,11. \

103L.-_.L..-.;"'-"-...........-~--'------'----'_...L---'-_

10 24 9 23 26 31 4 6 II 13FE~ MARCH APRL

FIGURE 15. VARIATIONS IN PHOSPHATE-PHOSPHORUSCONCENTRATIONS AT STATIONS 7 AND 9IN KANEOHE BAY? OAHU? 1968.

10

KMCAS STP AREA

....EUl:>

'"~ 162

a.UloJ:a.w~J:a.UloJ:a.

10"' '-----.J10'---'2-4"'-'9.L...J.23,.----L26~31--"-4--:-6----'-11---:13

FEB. MARCH APRIL

FIGURE 16. VARIATIONS IN PHOSPHATE-PHOSPHORUSCONCENTRATIONS AT STATION 8IN KANEOHE BAY? OAHU? 1968.

25

In addition to the Kaneohe outfall plume area, the nearshore

stations beyond the mouths of Kaneohe and Keaahala streams exceeded

the phosphorous limit of 0.025 mg/l for Class A waters on one and two

occasions.

Piyakarnchana (1965) and Tseu (1952) both concluded that the

phosphate concentration in the waters of Kaneohe Bay did not exceed 0.5

myg-atom per liter (0.0155 mg/l). Piyakarnchana obtained samples of

phosphates at a location approximately northwest of the Kaneohe sewage

treatment plant outfall. During two diurnal surveys, July and December,

1963, he found an increase in the phosphate concentration during the

night (near midnight) and a decrease during early morning hours (0500

to 0800 hours). He concluded that the fluctuation in phosphates was

primarily the result of photosynthetic activity during the day.

TRANSPARENCY. Turbidity measurements were taken on each survey with a

12-inch Secchi disc. Because of its many inherent limitations and the

shallowness, especially during low tide, of many of the streams and near

shore sampling stations, readings could not be obtained on a continuous

basis except at Stations 3, 6, 7, 8, and 9.

The readings at Station 1 ranged from 0.5 to 1.5 meters. Only one

reading was obtained from Station 2 on March 23, with a reading of 1

meter. During the other surveys, the water was too shallow to obtain a

reading. At the Kaneohe sewage treatment plant outfall (Station 3)

readings ranging from 0.5 to 2.5 meters were observed. Only five read­

ings were obtained at Station 5 with transparency ranging from 0.5 to

1.0 meters. At Station 6, eight readings were observed with transparency

ranging from 0.5 to 3.0 meters.

From mid-bay to the northern portion of the Bay, the turbidity was

less than that observed at the nearshore stations along the southern

portion of the Bay. At Station 7, the observed transparencies ranged

from 3.5 to 7.5 meters. (The high reading was recorded while the ob­

server wore polaroid sunglasses, a practice which should be avoided.)

However, this single reading was the only one in the whole study ob­

tained in this fashion so that the other transparency data are not af­

fected.

In the vicinity of the KMCAS sewage outfall, the transparency

26

observations ranged from 1.5 to 4.0 meters. The 4.0-meter reading was

not in the plume nor were the three other readings observed during the

early period of the surveys. The highest overall transparency readings

occurred at Station 9 in the channel with readings ranging from 3.0

to 5.5 meters.

Following high streamflows, the streams and the nearshore areas on

either side of the stream mouths carry predominantly silty turbidity.

Over a l3-month study, Piyakarnchana (1965) concluded that the turbid

waters off Keaahala Stream mouth originated from land runoff, bringing

large amounts of silt and small sand particles into the Bay. The sus­

pended silt was then spread throughout the Bay by wind and water move­

ment.

Turbidity and the subsequent siltation reduce the quality of estu­

arine waters for intended uses and alter the estuarine system as a biolo­

gical habitat. Silt is a pollutant and the rate at which it is intro­

duced into estuarine systems has been grossly accelerated by man's

activities.

Turbidity standards have been established for Class A waters, based

upon the Secchi disc equivalent coefficient, not to exceed those under

natural conditions by more than 10 percent. However, natural conditions

following a heavy rain at either stream mouth should not be compared to

the water clarity at mid-bay, for example. These two environments are

different in that one receives the suspended load from the adjacent land

and the other is nearly unaffected by surface runoff. As more surveys

are conducted, however, an accumulation of transparency data will be

acquired so that baselines for turbidity determinations can be estab­

lished. This would certainly eliminate an array of turbidity standards

which may be established by each investigator.

CHLORINITY. The chlorinity data (Figures 17, 18, and 19) indicate that

extreme variations in salt content occurred in the lower reaches of

Kaneohe and Keaahala streams (Stations 1, 2, 5 and 6). Figures 17 and

18 show the chlorinity concentrations at these four stations. Follow­

ing high rainfall and subsequent high streamflow, the dilution effect

of fresh water is observed approximately 100 yards beyond these two

streams. The chlorinity data at Stations 1 and 2 also show that the

(6)

(5)

,--, KEAAHALA STR MCUTH

"

\ ~ ....\ /

I \ ~

"j\ (I \ 'I \ I

J. \ I\ I\ /~ ,\ / \ I~ \,

~

18.0

0.0! '. .'. ' d3 d6 ~I ~ ~ il 1'3

MARCH APRIL

4.0

16.0

2.0·

6.0

14.0

20.0

o~ 12.0o

>­....Z 10.0ii:g:I:U 8.0

--..,,I,I\IIIIIIIIIII\IIIIII

~,2.0

6.0

4.0

16.0

14.0

18.0

10 24 9 23 26 31 4 6 II 13FEB. MARCH APRIL

• KANEOHE STP (3)20.0 r QKANEOHE STREAM 0)

.MOUTH OF KANEOHE STREAM (2)

0.0 I " I - I I I I ..

g 12.0.....

>-~ 10.0~a::gG 8.0

FIGURE 17. CHLORINITY VARIATIONS AT STATIONS1, 2, AND 3 IN KANEOHE BAY, OAHU,1968.

FIGURE 18. CHLORINITY VARIATIONS AT STATIONS5 AND 6 IN KANEOHE BAY, OAHU, 1968.

N-...J

28

4.0

30If)

W:J:UZ-. 2.0...J...J

~Z

~ 1.0

18.0

oo"'17.0~~

Z

§16.0:J:u

15.0

COCONUT ISLAND

EAST OF COCONUT ISLAND (7)

14.0 I-l...-l...-l...-.l..-l...-.l..-.l..--L.-..L-..L-...L.-...L.-...L.-............19.0

~ 18.0~~za:917.0

5 KMCAS STP AREA (8)

16.0 I-l...-l...-l...--L.-.l..--L.-.l..--L.-..L-..L-...L.-...L.-"""'-............19.0

o~ 18.0

~~za:9 17.0:J:u

Dour '27' (9)

16.0 L...-5.l..-I.l-O -,.1-&-20-'--2-'-5-2-'-'----'-5----'-'O----'-15----'-20---&.25----L51~&~'O~15

FEBRUARY MARCH APRIL

FIGURE 19. CHLORINITY VARIATIONS AT STATIONS7, 8, AND 9 WITH RESPECT TO RAIN­FALL RECORDED AT COCONUT ISLANDIN KANEOHE BAY, OAHU, 1968.

29

source of nitrate-nitrogen is land runoff. An inverse relation between

nitrate-nitrogen and chlorinity occurred at Keaahala Stream and beyond

its mouth (Stations 5 and 6).

Figure 17 shows the chlorinity concentrations observed at the

Kaneohe municipal outfall (Station 3). The trend is similar to that at

Stations 1 and 2 but not as pronounced. The lowest observed concen­

tration was 10.81 0/00 on March 26. The chlorinity level then gradually

recovered to 17.91 and 17.72 0/00 in early April. It is possible that

the fan of fresh-water runoff in late March was of sufficient volume to

effect some dilution on the surface water at this station.

Figure 19 shows the chlorinity levels at the three stations, from

mid-bay to the northern portion of the Bay, with respect to rainfall

recorded at Coconut Island. Of the three sampling sites, the one east

of Coconut Island (Station 7) showed the widest variation in chlorinity,

especially following almost four inches of rainfall recorded at Coconut

Island. Between ten days of sampling, from March 26 to April 4, the

chlorinity decreased from 17.23 to 14.90 0/00. Only a slight decrease

in chlorinity was observed at the KMCAS outfall area (Station 8) for this

same interval. However, after the March 31 decrease in chlorinity, none

of these stations recovered to the chlorinity levels prior to the heavy

rainfall period. At Station 8, the lowest chlorinity was observed at

17.04 0/00 on April 6, which did not follow the general pattern at

Stations 7 and 9.

Chlorinity and salinity observations in this portion of the Bay

by other workers (18.7 to 19.6 0/00 by Tseu, 1952, Piyakarnchana, 1965

and Bathen, 1968) indicate that the concentrations reported in this

study were generally lower than in past years.

The highest chlorinity observed was 18.3 0100 (33.06 0/00 S) on

several occasions during this study. The lower overall chlorinity

observed during this project may have been the result of analytical

technique or the presence of a low-salinity water mass off the Hawaiian

Islands. The Bureau of Commercial Fisheries Laboratory have spot

checked the salinity from waters collected at their fish trap (off the

fringing reef southeast of KMCAS pier). They also observed salinities

below normal during the early spring of 1968 (Ito).

30

DISSOLVED OXYGEN. The dissolved oxygen content observed in the Bay was

generally quite high in March and April. Oxygen saturation levels were

d~termined using Richards and Corwin's (1956) nomogram which presents the

solubility of oxygen as a function of temperature and chlorinity. The

dissolved oxygen concentrations ranged from 90 to approximately 120 per­

cent. On two occasions, March 9 and 31, oxygen saturations were 69 and

45 %0, respectively, at Station 5, Keaahala Stream. Since the two

samples represent observations prior to and following high rainfall and

streamflow, it is possibie that a sufficient amount of organic matter

settled into the pool area where the bacteria utilized some of the oxygen

during the active decomposition process.

Oxygen enters water from the atmosphere and through photosynthesis

production. The oxygen samples collected during these surveys were from

a depth of one meter below the surface so that oxygen introduced at the

surface by partial-pressure differential and through wind-induced tur­

bulence would be at a minimum. Therefore, the oxygen saturations above

100 percent can be attributed to the phytoplankton biomass present in

the surface waters. Piyakarnchana (1965) observed during a diurnal sur­

vey in July 1963, that the subsurface (7.6 meters) oxygen content was

slightly lower than that observed at the surface. He also observed on

three diurnal surveys -- April, July, and December 1963 -- that the oxygen

content in the surface water generally remained above supersaturation.

The temperature regime observed in Kaneohe Bay did not vary wide­

ly during the survey period. Prior to the heavy rain observed on March

23, the temperatures recorded at all stations averaged about 25°C.

During the high rainfall and streamflow on March 23, the temperature in

o °the streams and nearshore areas showed a drop of 2 to 21 and 22 C,

while from mid-bay to the northern area, the temperature dropped to 23°C.

On April 6, the temperatures at all stations returned to 25 to 26°C and

remained fairly constant through April 13. It can be concluded that the

temperature variation observed will vary with rainfall and the amount of

sunlight available. Since the samples were collected 1 meter below the

surface, air temperature probably had minimal effect on water tempera­

ture. Similar results with lower readings in February and March rising

to about 24 to 25°C in April were observed by Tseu (1952), Piyakarnchana

(1965), and Bathen (1968).

31

pH. The pH values observed in the streams and in the Bay were on the

alkaline side, ranging from 7.8 to 8.6. These values are listed in

Table 2.

TAB LE 2. PH RANGE AT EACH S,AJv1PLI NG STATI ON I N THESOUTHERN PORTION OF KANEOHE BAY7 OAHU

PH

STATION MINIMUM MIlJ< IMUM

8.0 8.6

2 7.9 8.2

3 8.1 8.6

5 7.8 8.1

6 8.0 8.6

7 8.1 8.5

8 8.1 8.5

9 8.1 8.5

The pH observations, unfortunately were not measured in the field,

but in the laboratory. The possible changes in pH units which may have

occurred between collection and determination are therefore unknown. It

is also difficult to assess the significance of the limited pH data in

relation to some of the other parameters such as dissolved oxygen and

temperature since no defined trends can be established from these

limited measurements. In general, however, the pH observations

at all of the stations met the standards established for water quality

in Kaneohe Bay with the exception of two samples collected on March 31

at Stations 3 and 6. Both samples yield~d a pH reading of 8.6 which is

0.1 pH unit above the upper limit established for Class A waters.

As more pH observations are accumulated, especially in conjunction

with diurnal studies of phytoplankton production and respiration, and

dissolved oxygen content, the pH determinations will be more meaningful

in interpreting the planktonic ecosystem in the southern portion of

Kaneohe Bay. Gundersen and Stroup (196/) observed pH values in the

southern portion of the Bay to vary from 7.5 to 8.1 in surface waters

32

and from 7.0 to 8.2 in the bottom waters at three station sites in the

southern, mid-, and northern portions of the Bay. Of six separate

samples obtained n~ar the Kaneohe sewage outfall plume, they observed

only one lower than 8.0 in the surface water and three in the bottom

water. They also concluded that pH is not necessarily indicative of

polluted waters and that it should be interpreted with caution.

33

CONCLUSIONS

Based upon ten surveys performed in the southeastern portion of

Kaneohe Bay between February and mid-April 1968, a number of conclusions

are presented.

1. The fecal streptococci population density coincides with the

amount of streamflow in Kaneohe Stream and in the waters over­

lying the clam bed to the west of the Kaneohe Stream mouth.

2. Of the two nutrients, nitrate-nitrogen increased greatly over

dry-weather flow in the lower reaches of the streams and near­

shore waters. Phosphate-phosphorus was not affected signifi­

cantly by surface runoff.

3. The turbidity in the streams and nearshore waters was caused

by silt during periods of high streamflow.

4. High surface runoff and rainfall lowered the surface water

temperature 2°C in the streams and throughout the southeastern

portion of Kaneohe Bay.

5. The primary contributors of phosphate-phosphorus were the

Kaneohe municipal and the Kaneohe Marine Corps Air Station

sewage treatment plants.

6. During periods of dry weather flow, the water quality in the

southeastern portion of Kaneohe Bay met the standards of

Class A and AA waters.

7. During wet-weather streamflows, nitrate-nitrogen exceeded the

standards for Class A waters in the streams and nearshore

waters.

8. When the Kaneohe municipal sewage treatment plant discharged

effluent above a rate of 3 MGD, the phosphate-phosphorus

concentration exceeded the limit for Class A waters.

ACKNOWLEDGEMENTS

The assistance of the following is gratefully acknowledged:

graduate students, Po Lau Chan, Jerry Nunogawa, and Billy F. Pearson,

who helped in the collection of samples from Kaneohe Bay; Dr. George

Markham, Assistant Professor of Environmental Sanitation, who also

34

helped with sample collections; and Dr. Kaare R. Gundersen and David

Stroupe of the Microbiology Department for providing sampling equip­

ment and supplies.

The assistance from the following agencies is also acknowledged:

the Division of Sewers, City and County of Honolulu; U. S. Navy Bureau

of Sanitation; U. S. Geological Survey; U. S. Weather Bureau; and U. S.

Fish and Wildlife Service, Bureau of Commercial Fisheries.

35

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American Public Health Association. 1965. Standard Methods for theExamination of Water and Wastewater. (1917) 12th Edition. TheAmerican Public Health Association, Inc., New York. XXXI. 769 p.

Bathen, K. H. 1968. A Descriptive Study of the Physical Oceanographyof Kaneohe BaY3 Oahu3 Hawaii. Technical Report No. 14. HawaiiInstitute of Marine Biology. University of Hawaii. 353 p.

Department of Health, State of Hawaii. 1968. Public Health Regulations.Chap. 37. Water Pollution Control. 4 p.

Department of Health, State of Hawaii.3?-A. Water Quality Standards.

1968.8 p.

Public Regulations: Chap.

Gundersen, K.KaneoheNo. 19.24 p.

R. and D. B. Stroupe. 1967. Bacterial pollution inBay 3 Oahu (June through August3 196?). Technical Report

Water Resources Research Center. University of Hawaii.

Iha, T. H. 1960. Survival of Sewage Bacteria in the Sea. M. S. Thesis.University of Hawaii. 54 p.

Ito, B. 1968. Personal Communication. U. S. Fish and Wildlife Service,Bureau of Commercial Fisheries. Honolulu, Hawaii.

Jenkins, D. and L. L. Medsker. 1964. "Brucine Method for Determinationof Nitrate in Ocean, Estuarine, and Fresh Waters." AnalyticalChemistry 36(4):610-612.

Kahn, L. and F. T. Brezenski. 1967. "Determination of Nitrate inEstuarine Waters: Comparison of a Hydrazine Reduction and aBrucine Procedure and Modification of a Brucine Procedure."Environmental Science and Technology 1(6):488-491.

Murphy, J. and J. P. Riley. 1962. "A Modified Single Solution for theDetermination of Phosphate in Natural Waters." Analytica ChimicaActa. 27(1):31-36.

Piyakarnchana, T. 1965. The Plankton Community in the Southern Partof Kaneohe BaY3 Oahu3 with the Special Emphasis on the Distribution3Breeding Season and Population Fluctuation of Sagitta EnflataGrassi. Ph.D. Thesis. University of Hawaii. 193 p.

Richards, F. A. and N. Corwin. 1956. "Some Oceanographic Applicationsof Recent Determinations of the Solubility of Oxygen in Sea Water."Limnology and Oceanography 1(4):263-267.

Slanetz, L. W. and C. H. Bartley. 1965. "Survival of Fecal Streptococciin Sea Water." Health Laboratory Science 2(3):142-148.

36

Strickland, J. D. H. and T. R. Parsons. 1965. "A Manual of Sea WaterAnalysis." Fisheries Research Board of Canada BuUetin. No. 125,2nd Edition. 203 p.

Sylvester, R. O. 1961. "Nutrient Content of Drainage Water fromForested, Urban and Agricultural Areas." In Algae and Metropo­litan Wastes. R. A. Taft Sanitary Engineering Center. SEC TRW6l-3:80-87.

Tseu, W. S. L. 1952. Seasonal Variations in the Physical Ecology ofthe Ponds at the Hawaii Marine Laboratory and the Adjacent Watersof Kaneohe Bay. M. S. Thesis. University of Hawaii. 87 p.

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APPENDIX: STATE OF HAWAII COMPREHENSIVEDEFINITION OF WATER POLLUTION

39

The state of Hawaii established water quality standards for all

coastal waters under the provisions of Sections 46-13 and 46-16, Revised

Laws of Hawaii 1955, Chapter 37 of the Public Health Regulations.

Chapter 37-A contains the amended standards of water quality based upon

the Water Quality Act of 1965, Public Law 89-234.

According to the Public Health Regulations, Department of Health,

State of Hawaii, Chapter 37, Water Pollution Control, the comprehensive

definition of water pollution is:

1. Such contamination, or other alteration of the physical,chemical or biological properties, of any waters of thestate, including change in temperature, taste, color,turbidity, or odor of the waters, or

2. Such discharge of any liquid, gaseous, solid, radio­active, or substance into any waters of the state, aswill likely to create a nuisance or render such watersunreasonably harmful, detrimental or injurious to publichealth, safety or welfare, including harm, detriment orinjury to public water supplies, fish and aquatic lifeand wildlife, recreational purposes, and agricultural,industrial, research and scientific uses of such waters.