OCEAN CURRENTS AND CIRCULATION AVARUA - MOTUTOA, RAROTONGA COOK ISLANDS

Brendan Holden SOPAC Technical Secretariat

April 1992 SOPAC Technical Report 143

Prepared for: South Pacific Applied Geoscience Commission (SOPAC) Coastal and Nearshore Programme, Cook Islands Project: CK.4 [3]

TABLE OF CONTENTS

Page SUMMARY ...... 5 ACKNOWLEDGEMENTS ...... 6

OBJECTIVES ...... 7 INTRODUCTION ...... 7

METHODS ...... 10 RESULTS Wind ...... 13 Waves ...... 13 Water Levels ...... 15 Water Temperatures ...... 16 Current Data ...... 19 Avarua Top ...... 19 Avarua Bottom ...... 19 Motutoa Top ...... 20 Motutoa Bottom...... 21 Motutoa Drogues and Dye ...... 21

DISCUSSION Currents ...... 22 Sewer Outfalls ...... 23

CONCLUSIONS ...... 48 RECOMMENDATIONS ...... 48

REFERENCES ...... 49

APPENDICES A Rarotonga Tide Predictions (January - April 1991) B Notes on Data Analysis Methods (Malcolm Greig)

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LIST OF FIGURES

Figure Page 1 Rarotonga Site Map ...... 8 2 Avarua - Motutoa Site Map ...... 9 3 Current Meter Mooring ...... 11 4 Drogue : Window blind type ...... 12 5 Wind Rose : Southern Cook Islands ...... 14 6 Avarua - Water level data ...... 17 7 Avarua - Filtered Water Level Data ...... 18 8 Avarua Top - Current Meter Data ...... 24 9 Avarua Top - Filtered Non Tidal Data ...... 25 10 Avarua Top - Tidal Current ...... 26 11 Avarua Top - Current Rose ...... 27 12 Avarua Top - Progressive Vector ...... 28 13 Avarua Bottom - Current Meter Data ...... 29 14 Avarua Bottom - Filtered Non Tidal Data ...... 30 15 Avarua Bottom - Tidal Current ...... 31 16 Avarua Bottom - Current Rose ...... 32 17 Avarua Bottom - Progressive Vector ...... 33 18 Motutoa Top - Current Meter Data...... 34 19 Motutoa Top - Filtered Non Tidal Data...... 35 20 Motutoa Top - Tidal Current ...... 36 21 Motutoa Top - Current Rose...... 37 22 Motutoa Top - Progressive Vector ...... 38 23 Motutoa Bottom - Current Meter Data ...... 39 24 Motutoa Bottom - Filtered Non Tidal Data ...... 40 25 Motutoa Bottom - Tidal Current ...... 41 26 Motutoa Bottom - Current Rose ...... 42 27 Motutoa Bottom - Progressive Vector ...... 43 28 Drogue and Dye Tracks - 15 March 1991 ...... 44 29 Drogue Tracks - 19 March 1991 ...... 45 30 Drogue Tracks - 25 March 1991 ...... 46 31 Current Rose and Resultant Vector Summary ...... 47

[TR143 - Holden] SUMMARY

In the early 1980s, a sewage collection system with a marine outfall was proposed off Aavarua Harbour. Since there were no current data off Avarua, the Government of the Cook Islands requested SOPAC to undertake Task 91.CK.4d: Physical Oceanography of Avarua - Avatiu and nearshore areas. This task began with the mooring of current meters off Avarua early in 1991. During the course of this field work, it became known that another proposal was recommending a more extensive sewage collection system with an outfall off Motutoa near the airport.

Subsequently Task 91 .CK.4d was extended to include Motutoa, and current meter moorings with two Aanderaa current meters (top & bottom) were deployed off both Avarua and Motutoa. In addition, rhodamine dye and drogues were released and tracked off Motutoa. The current meter data off Avarua showed a net southeasterly current (onshore) at the top meter and a net southwesterly current (into the harbour) at the bottom meter. The current meter data off Motutoa showed a net northwesterly current (away from Rarotonga) on both the top and bottom meters.

It is recommended that the sewer outfall proposal for Avarua be abandoned because the currents are not suitable to carry away the effluent. It is recommended that the proposal for a sewer outfall off Motutoa be considered further because it is more environmentally safe.

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ACKNOWLEDGEMENTS

This work was supported by the Canadian International Development Agency (CIDA) and the Government of the Cook Islands.

Gratitude is expressed to the many Cook Islands Government personnel who assisted with the field work for this study : Stuart Kingan, SOPAC National Representative; Tony Utanga, Ministry of Internal Affairs; George Cowan, Ministry of Public Works; K. Kamana and T. Short, for use of the Tug boat; R. Story and other personnel of Marine Resources for diving and current meter retrieval; Ata Herman, Sonny Tatuava, Tara Tairea and John Temata for drogue tracking.

Data was processed, analysed and plotted by Malcolm Greig of New Zealand Oceanographic Institute (NZOI), DSIR, under contract to SOPAC with financial assistance from the New Zealand government.

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OBJECTIVES

This work was carried out to fulfill the requirements of the 1991 SOPAC Work Plan, Task 91 .CK.4d: Physical oceanography of Avarua - Avatiu harbours and nearshore areas. The objective of this task was to determine the ocean current regime off Avarua as design and planning data for a proposed sewer outfall. A later proposal for a sewer outfall off Motutoa (airport) required that the task be extended to include this area. This report describes and discusses the ocean current data collected off Avarua and Motutoa in 1991 and the implications of these current data on the location of a sewer outfall.

INTRODUCTION

Avarua, Avatiu and Motutoa (Lat 21' 12'S, Lon 159' 47'W) are located on the north side of Rarotonga, Cook Islands (Figures 1 & 2). Avarua and Avatiu are adjacent small towns with a total population of about 5000. Both towns have small fresh water streams and gaps in the reef which provide entrances to the small harbours. Motutoa is a small island on a wide section of the reef flat off the airport where there is no gap in the reef. The bottom slope at both sites is 5% from the reef crest out to about the 25 m depth and then increases rapidly to 40% into deep water.

The purpose of this report is to describe and discuss the currents and circulation off Avarua and Motutoa on the north side of Rarotonga, Cook Islands (Figure 1). The gathering of these data has been described in previous SOPAC preliminary reports (Holden 1991a, Holden 1991 b). The original task was SOPAC Task 91.CK.4d: Physical Oceanography of Avarua, Avatiu and nearshore areas, which was extended to include Motutoa (Figure 2). This report represents the completion of Task 91.CK.4d under the title "Ocean Currents and Circulation: Avarua - Motutoa''.

This task was originally requested by the Government of the Cook Islands because of a proposal to put a sewer outfall off Avarua Harbour (Ludwig 1980, 1981, Ludwig et al 1982). During the field work to moor current meters off Avarua, it was discovered that a more recent sewer outfall proposal was being considered for Motutoa (Tonkin & Taylor 1988). It appears that no current meter data had ever been collected at either of these sites. Both sewer outfall proposals (Ludwig et al 1982, Tonkin & Taylor 1988) proceeded on the assumption that the current flowed westward in this area. It is quoted by Tonkin & Taylor (1988) from the Ludwig et al (1982) report'' No measured ocean current data is available ... the direction of surface currents has been

[TR143 -Holden]

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Figure 2. Aval site

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observed at the edge of the coral reef in the vicinity of Avatiu Harbour ... there was no tendency for movement into the harbour ...". Following the discovery of the second sewer outfall proposal, again without current meter data, it was recommended that current meter data also be collected off Motutoa.

Subsequently, a similar current meter array was moored off Motutoa (Figure 3) and current meter data were collected for six weeks at both sites. In addition, drogues (Figure 4) and rhodamine dye were tracked off Motutoa and a water level recorder was placed in Avarua Harbour. Both the Avarua and Motutoa data are included in this report since the common purpose is the planning of a sewer outfall location.

METHODS

The first step in this study was to review any previous work on the physical oceanography of the north side of Rarotonga. It appears that the two sewage outfall proposals (Ludwig et al 1982, Tonkin & Taylor 1988) were prepared on the assumption that the currents were westward. There is no known current meter data previous to the data presented in this report.

Off Avarua, a current meter array consisting of two Aanderaa RCM 4 meters (Figure 3) was moored from 29/01/91 to 14/03/91 (Figure 2). These meters were retrofitted with the new rotors and rotor cages now used on the RCM 7 meters. These new rotors are less influenced by wave action than the original savonius rotors. It was hoped to moor the current meter array closer to the end of the proposed outfall but the offshore bottom slope was too steep (40% ) and there was some risk of the anchor tumbling down the slope. Since the nearshore bottom slope is about 5%, the array of two meters and the site at 24 m depth were chosen as a compromise. The top and bottom meters respectively, were moored 9 m down from the surface (15 m off the bottom) and 20 m down from the surface (4 m off the bottom). Both these current meters had sensors for conductivity, temperature, pressure, speed and direction and functioned throughout the data collection period. The details of the mooring of this current meter array are given in Holden (1991).

Off Motutoa, a similar current meter array consisting of two Aanderaa RCM 7 meters (Figure 3) was moored from 19/03/91 to 30/04/91 (Figure 2). Because this site had the same general bottom slopes as at Avarua, the same mooring arrangement and water depth (24 cm) was chosen. The top and bottom meters respectively, were moored 9 m down from the surface (15 m off the bottom) and 20 m down from the surface (4 off the bottom). Both these current meters had

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CURRENT MOORING

SURFACE-

2m

marker rope ( floating) I 11m

I

e{;t Currentmeter

4m Bottom line -50m (floating rope) Chain, -~--v /\- SMALL

Figure 3. Current meter mooring.

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METER [12]

DROGUE (For Tracking Ocean Currents) r:>

MARKER FLOAT--

ROPEADJUSTABLE I

WOOD STRIPS

FABRIC MATERIAL

115cm

WEIGHTED ROD IN POCKET

Figure 4. Drogue: window blind type.

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~ [13]

sensors for temperature, speed and direction and functioned well throughout the data collection period. The details of the mooring of these meters are given in Holden (1991).

During the field trip to moor the Motutoa current meters, drogues and a rhodamine dye patch were tracked and an Aanderaa water level recorder was placed adjacent to the permanent TOGA tide gauge in Avarua Harbour. This water level recorder was installed to obtain tide data which were readily compatible with the current meter data. Some additional drogue tracking was done during April by personnel of the Cook Islands Government.

The current meter and water level data were first read and transferred to an IBM - PC at SOPAC using Aanderaa equipment and software (P 3059 Data Reading Program). Initial data processing and preliminary analysis of the data was done at SOPAC with the same Aanderaa software. Further processing, plotting and more detailed analysis of the data was done by Malcolm Greig at the New Zealand Oceanographic Institute (NZOI). The drogue and rhodamine dye tracks were plotted and drafted at SOPAC. The final analysis of the data and report writing was done at SOPAC.

RESULTS

Wind

The only available wind summary for Rarotonga is from the New Zealand Meteorological Service (Thompson 1986). Rarotonga lies in the South Pacific trade wind zone and winds from the easterly quadrant blow over 50 percent of the time. Since Rarotonga is a sizeable island, diurnal direction changes result from local land and sea breeze effects. The land and sea breezes can enhance or diminish the dominant easterly trade winds. Open ocean surface wind estimates (Thompson 1986) have been plotted as a wind rose (Figure 5) to show the dominance of the easterly trade winds off Rarotonga.

Waves

Wave measurements were made by a Waverider buoy off the south east coast of Rarotonga from July 1987 to January 1991. These wave data are available on IBM-PC compatible diskette at SOPAC or from Oceanor (Olsen et al 1991).

[TR143 - Holden] [14]

N /""""",,"""~~-' '-1 I ~ "'" / +/.-- ~"" I '-" -'/' " "'" / "" / \

E

/ / / / -'/' '---""- /

/ J'~ -"""" ~~~~-_/

0-9 10-14 15-19 20-24 25+ Knots

WIND ROSE

SOUTHERNCOOK ISLANDS

OPEN OCEAN SURFACEWIND ESTIMATES

Nt. ZealandMt'trxolagicm s..v;ct

SOPAC-CK904

Figure 5. Wind Rose: Southern Cook Islands.

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"'//,,-"""~---lJ...1~'\./ [15]

The most common sea states observed by the wave buoy are between 1.75 and 2.25 m with an everage of 2.2 m significant wave height. Slightly higher wave heights are observed in winter (April - October), with an average significant wave height of 2.27 m, compared to summer (November - March) when the average is 1.93 m. This is due to the combined effect of higher swell energy in the winter (from storms mostly to the south and southwest) and somewhat higher wind seas due to higher trade winds at that time of year (Olsen et al 1991).

It is estimated that about 1-2 tropical cyclones affect the Southern Cook Islands each year; however, only one cyclone significantly affected the wave climate during the measurement period. This was cyclone Peni which passed close to Rarotonga on 15th February 1990. Although winds only just exceeded gale force at Rarotonga (the storm having hurricane force winds near its center) significant wave height reached 7.6 m at about the time of the storm center’s nearest approach. Although Cyclone Ofa was situated off Western Samoa on 2-4 February 1990, and Cyclone Sina passed through Tonga 28-29 November 1990, there were no indications of very large waves on the Rarotonga data.

It is difficult to estimate extreme wave heights likely to be encountered at Rarotonga based on one cyclone event, but it is likely that significant wave height exceeding 10 m will be experienced. Maximum wave height may be assumed to be 1.8-1.9 times the significant height. Associated wave periods are not likely to be greater than 15-18 secs.

On the northern coast of Rarotonga, average wave conditions are likely to be somewhat lower than at the measurement site as this coast is relatively sheltered from the southerly swells and south to southeasterly trade wind seas. However, extreme cyclone driven seas may be as high as those described above (written communication Barstow, Olsen et al 1991).

Water Levels

The astronomical tides at Avarua are based on the standard tidal reference port of Auckland, New Zealand. The Rarotonga tides are mainly semi-diurnal with two high and two low tides each day. The maximum astronomical tidal range is about 1.1 m although this range will only occur a few times in the 18.6 year astronomical cycle. The mean spring tidal range is about 0.6 m and this can be expected to occur about every two weeks around the time of new and full moons (Admiralty Tide Tables 1990).

[TR143 - Holden] [16]

The TOGA Sea Level Center maintains a tide gauge at Avarua and makes tide predictions for Rarotonga, based on the data collected at Avarua. These predictions indicate a maximum tidal range of about 0.9 m at Avarua for the 1991 year (Wyrtki 1991). These tide predictions were used in planning field work and analysing the data and are included as Appendix A.

An Aanderaa water level recorder was moored adjacent to the TOGA tide gauge in Avarua Harbour from 20 March to 30 April 1991. This instrument was moored to facilitate comparisons with the current meter data at Motutoa. The instrument recorded both water level changes and water temperatures throughout the data collection period. These data are plotted as a time series in Figure 6 and as filtered data in Figure 7*.

The water level recorder data from Avarua Harbour shows semi-diurnal tides with fortnightly lunar cycles of spring and neap tides. The daily tidal range varied from a minimum of about 0.2 m on 9 April to a maximum of about 1 m on 19 April. This water level recorder was not surveyed to chart datum or mean sea level so the data cannot be assumed to represent water level or mean sea level. For a more extensive study, the long term tide record can be obtained from the TOGA Sea Level Centre in Hawaii (Wyrtki 1991).

Water Temperatures

The water temperature data from the Aanderaa water level recorder indicate that the water temperature in Avarua Harbour had a usual daily range between 27' C and 29' C over the period of record (Figure 6). The highest water temperature was 29.37' C on 30 March and the lowest was 26.51' C on 19 April 1991. The data showed diurnal heating and cooling with the lowest temperatures usually at dawn and highest in late afternoon. There was also a slight lowering of the average water temperature from March to the end of April, a seasonal cooling effect (Figure 7).

There was one anomalous period of several days (2-5) April) when the data did not show the usual diurnal heating and cooling (Figure 6). The Nadi weather charts show a low pressure system and cloud cover over the Rarotonga area for this period and it is believed that heavy cloud cover could have shielded against solar heating and prevented the daily heating and cooling.

......

*Onwards of Figure 7, see from page 24.

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[19]

Current Data

Current meter data was collected by a vertical array of two current meters off both Avarua and Motutoa (Figure 2). The two sites had the same mooring arrangement with the bottom meter near the anchor and the top meter just under the subsurface float (Figure 3). These meters are referred to as top and bottom at each site.

Avarua Top

This meter worked well throughout the data collection period, except the conductivity readings had considerable data noise. Data for temperature, current speed and direction are plotted on Figures 8 to 12.

The salinity readings varied alternately between 30% and 40% or between 34% and 50% throughout the data collection period, indicating that the conductivity sensor on this meter was faulty.

The water temperature was generally about 28' C throughout the period with no clear evidence of either diurnal or seasonal heating or cooling tends. The temperature fluctuated slightly for the first two weeks of February with a maximum of 29.37' C and a minimum of 26.59' C (Figures 8,9).

The current speed was generally between 5 and 10 cm/sec with a few short duration peaks up to a maximum of 26.9 cm/sec on 2 March 1991 (Figure 8). The current direction varied around all points of the compass with a slight bias of westerly and southeasterly directions (Figures 8,11). The progressive vector diagram (Figure 12) shows a net southeastward current toward the reef. The resultant current vector over the 44 days of record was 1 km per day toward 124' true.

Avarua Bottom

This meter worked well throughout the data collection period. Data for temperature current speed and direction are plotted on Figures 13 to 17.

[TR143 - Holden] [20]

The salinity was about 35% with some fluctuations throughout the data collection period.

The water temperature was slightly below 28' C throughout most of this period and showed no evidence of either diurnal or seasonal heating or cooling trends. The temperature fluctuated throughout the data collection period and fluctuated more than at the top meter for the first three weeks of the record. The temperature had a maximum of about 28.4' C and minimum of about 25.5'C (Figures 13, 14).

The current speed was generally about 5 cm/sec with some short duration peaks up to a maximum of 23.9 cm/sec on 2 March 1991 (Figure 13). The speed was slightly lower than the top current meter at this site. The current direction varied around the compass with a slight bias of westerly and southeasterly directions, similar to the top meter (Figure 13, 16). The progressive vector diagram (Figure 17) shows a net southwestward current toward Avarua Harbour entrance. The resultant current vector over the 44 days of record was 0.33 km per day toward 212' true.

Motutoa Top

This meter worked well throughout the data collection period. The data for temperature, current speed and direction are plotted on Figures 18 to 22.

The water temperature showed little short term fluctuation throughout this period, gradually changing from about 28.5' C in late March to about 27.5' C at the end of April. The maximum temperature was 28.61' C and the minimum was 27.25' C. The lowering of water temperature over this data collection period is believed to be seasonal cooling. There was no evidence of any diurnal heating and cooling (Figures 18, 19).

The current speed fluctuated with the tidal cycle from zero up to a maximum of 96.7 cm/sec on 23 March 1991 (Figure 18). The current direction usually varied between easterly and westerly with the dominant direction being west-northwestward (Figures 18, 21). On several occasions the current direction remained west-northwestward for over 24 hours (Figure 18). The progressive vector diagram (Figure 22) shows a strong net current toward the west northwest away from Rarotonga. The resultant current vector over the 42 days of record was 5.2 km per day toward 284' true.

[TR143- Holden] [21]

Motutoa Bottom

This meter worked well throughout the period of data collection. The data for temperature, current speed and direction are plotted in various ways as Figures 23 to 27.

Although water temperature showed more and greater downward fluctuations than the top meter at this site, the filtered temperature (Figure 24) was not significantly different than the top meter. The water temperature gradually changed from about 28.3' C in late March to about 27.5' C at the end of April, indicating seasonal cooling. The maximum temperature was 28.52' C and the minimum was an instantaneous low reading of 25.95' C. There was no evidence of diurnal heating and cooling in this data (Figures 23, 24). The downward temperature fluctuations are believed to be caused by intrusions of cooler deep ocean water.

The current speed fluctuated with the tidal cycle from zero up to a maximum of 46.4 cm/sec on 23 March (the same time the top meter speed peaked). The current direction usually varied between easterly and westerly with the dominant direction being west-northwestward (Figure 23, 26). On several occasions, the current direction remained west-northwestward for over 24 hours (Figure 23). The progressive vector diagram (Figure 27) shows a strong net current toward the west-northwest, away from Rarotonga. The resultant current vector over the 42 days of record was 3.9 km per day toward 290' true.

Motutoa Drogues and Dye

Drogues (Figure 4) were tracked off Motutoa (Figure 2) on 15, 19 and 25 March and on the 5, 8, 12, 15, 22, and 26 April 1991. On 15 March, rhodamine dye was also released at the Motutoa current meter mooring and tracked until it was no longer visible. The drogue and dye tracks for 15, 19 and 25 March, are plotted on Figures 28 - 30.

On 15 March 1991, two surface drogues, two 20 m depth drogues and rhodamine dye were released at the Motutoa current meter mooring site (Figure 2, 4). The releases were made at high tide and tracked for about three hours (Figure 28). Although the wind was from the east throughout this exercise, all the drogues and the dye patch moved eastward relatively fast. This current direction was unexpected and was the first proof that the current cannot be assumed to be always westward. The dye patch moved eastward and offshore at about 15 cm/sec and was no longer visible after about two and a half hours. The surface drogues moved east at about the

[TR143 - Holden] [22]

same speed as the dye patch for the first two hours and then slowed to about 5 cm/sec. The 20 m depth drogues moved fastest at about 20 cm/sec eastward and passed east of Avatiu Harbour entrance about three hours after high tide.

On 19 March 1991, two surface drogues and two 20 m depth drogues were released at the Motutoa current water mooring at high tide and tracked for about three hours (Figure 29). During this exercise the wind was from the west. All these drogues first moved westward slowly at about 10 cm/sec for about two hours and then turned eastward. When the drogues turned eastward, the surface drogues stayed together and moved faster (50 cm/sec) than the 20 m depth drogue (40 cm/sec). One of the 20 m depth drogues went aground near the reef (Figure 29).

On 25 March, two surface drogues and two 10 m depth drogues were released at the Motutoa current meter mooring about one hour after low tide and tracked for two hours (Figure 30). The wind was from the southeast and the swell from the east during this exercise. The surface drogues moved eastward for the first hour at about 20 cm/sec and then northwest at about 15 cm/sec. The 10 m depth drogues moved east and then northeast at about 6 cm/sec (Figure 30).

DISCUSSION

Currents

The current roses for all four current meters are presented together with the resultant current vectors on Figure 31 for this discussion comparing Motutoa and Avarua currents.

The current meter data for Avarua do not indicate a dominant current direction. Both current meters at Avarua show rotation about the compass with only a slight bias of west and east-southeast directions. The resultant current vector for the top meter is 1 km/day 124' T (toward the shore) and the resultant vector for the bottom meter is 0.33 km/day 212' T (toward Avarua Harbour entrance). This indicates that pollutants at this site would drift onshore and toward the entrance of Avarua Harbour. It is concluded that the ocean currents off Avarua Harbour are not suitable for sewage disposal.

The current meter data for Motutoa indicate the strong dominance of west-northwest and east-southeast current directions. The resultant current vectors for the top and bottom meters are

[TR143 - Holden] [23]

5.2 km/day and 3.9 km/day respectively toward 284' T and 2900 T. The drogue and dye tracking exercises off Motutoa indicate that the current moves both east and west. The drogue tracks of 15 March (Figure 28) indicate that pollutants could move as far east as Avatiu Harbour in about three hours; however, these pollutants would be significantly dispersed before reaching Avatiu, as was the rhodamine dye patch. It is concluded that the ocean currents off Motutoa are much more favourable than at Avarua for a properly designed sewer outfall, to disperse sewage and carry it away from Rarotonga.

Sewer Outfalls

The location of a sewer outfall is dependent on many factors, including engineering, economics, population, topography, ocean bottom features, waves, and ocean currents. This report presents data only on ocean currents.

The choice of Avarua for the earlier sewer outfall proposal (Ludwig 1982) was partly because of the relative ease of laying a sewer pipeline out through the reef gap (Figure 2). No current meter data had been collected. It is now known that the currents off Avarua are not suitable for a sewer outfall so this proposal must be abandoned.

Motutoa has more favorable ocean currents but there is no natural gap in the reef. The problem of putting a sewer outfall pipe through the reef crest will add additional engineering and economic problems to the project. The site off Motutoa has certain other advantages. The reef flat is relatively wide and the bottom slope is flatter off Motutoa so that the outfall would be about double the distance offshore for the same water depth as at Avarua. Since the Motutoa area is dominated by the airport, a sewage plume drifting onshore would not be as offensive as near Avarua - Avatiu or near a major hotel. The small island Motutoa is also a possible location for some sewer system facilities.

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[48]

CONCLUSIONS

1. The ocean currents off Avarua Harbour have a net drift toward the shore and the harbour entrance and are not suitable for sewage disposal.

2. The ocean currents off Motutoa have a significant net drift west-northwestward away from Rarotonga are suitable for a properly designed sewer. The Motutoa area has some additional advantages of having a wider reef flat and not being a residential or recreational hotel area.

RECOMMENDATIONS

1. That a sewer outfall not be located off Avarua Harbour.

2. That the Motutoa sewer outfall proposal be examined further with respect to engineering problems specific to the site.

3. That additional current data should be collected if the sewer outfall is to be moved significantly from the site of the Motutoa current meter mooring.

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REFERENCES

Admiralty Tide Tables 1990: Pacific Ocean and Adjacent Seas. Published by the Hydrographer of the Navy.

Holden B. 1991a: Physical Oceanography of Ngatangiia Harbour - Muri Lagoon and Avarua Harbour, Rarotonga Cook Islands. SOPAC Preliminary Report 30.

Holden B. 1991b: Physical Oceanography of Avarua - Avatiu - Motutoa, Rarotonga Cook Islands SOPAC Preliminary Report 31.

Ludwig R.G. 1980: Marine outfall sewer Planning and Preliminary Design, Avarua, Rarotonga, Cook Islands, WHO/PEPAS Assignment Report ICP/EHP/003.

Ludwig, R.G. 1981: Finalisation of designs for sewerage facilities including Marine outfall, Avarua, Rarotonga, Cook Islands, PEPAS/WHO Assignment Report, Reference ICP/EHP/003.

Ludwig, R.G., Ramos, M.C., Videnov, T. and Sirikige, P., 1982: ''Avarua CommonSewerage Effluent Collection System with Marine Outfall" Final Report Environmental Health Engineering Advisory Services Project, Cook Islands.

Olsen, E., Barstow, S.F., Selanger, K. 1991: Wave Data Collection, Rarotonga, Cook Islands, July 1987 - January 1991 Oceanor, Tronheim. Norway Oceanor Report OCN R 91071.

Thompson, C.S. 1986: The Climate and Weather for the Southern Cook Islands. New Zealand Meteorological Service. Miscellaneous Publication 188 (2).

Tonkin & Taylor International. 1988: Second Multiproject, Cook Islands, Rarotonga Sewerage system Subproject, Government of the Cook Islands, Ministry of Planning and Economic Development, Reference 8282.

Wyrtki, K. 1991: Toga Sea Level Centre. Tropical Ocean Global Atmosphere Project, University of Hawaii, Honolulu.

[TR143 - Holden] APPENDIX A

Rarotonga Tide Predictions

January 1991 - April 1991 TOGA SEA LEVEL CENTER University of Hawaii, 1000 Pope Road, MSB 430 Honolulu, Hawaii, 96822, USA. HIGH AND LOW WATERPREDICTIONS FOR Rarotonga LAT:21 12S LONG:159 46W, local time, heights' in feet NOTE: These tide predictions are based on data collected between May 1987 and June 1988. The mean sea level during this period was 1.86 feet. The datum for these tide predictions is the zero point of the tide staff at Avarua Harbour, Rarotonga Cook Island established in 1977. Please note that the quoted values are not related to chart datum and should be used with caution.

JANUARY 1991

Time Feet Time Feet Time Feet Time Feet 1 0344 0.6 9 0402 2.7 17 0453 1.2 25 0358 2.8 0953 2.9 0959 1.5 1059 3.0 0952 1.4 Tu 1600 0.8 W 1616 2.9 Th 1657 1.3 F 1622 3.2 2212 3.3 2257 1.5 2259 3.1 2302 1.3

2 0439 0.6 10 0458 2.6 18 0526 1.2 26 0503 2.7 1049 3.1 1048 1.6 1133 3.1 1054 1.5 W 1657 0.8 Th 1715 2.9 F 1733 1.2 Sa 1733 3.1 2307 3.3 2335 3.2

3 0531 0.6 11 0003 1.5 19 0559 1.2 27 0013 1.3 1142 3.2 0601 2.5 1207 3.2 0616 2.7 Th 1751 0.7 F 1146 1.7 Sa 1810 1.2 Su 1211 1.5 2358 3.3 1819 2.8 1848 3.1

4 0620 0.6 12 0109 1.5 '20 0012 3.2 28 0125 1.2 1230 3.3 0708 2.5 0632 1.2 0731 2.8 F 1842 0.8 Sa 1254 1.7 Su 1241 3.3 M 1336 1.4 1922 2.8 1849 1.2 2001 3.2 5 0048 3.3 13 0209 1.4 21 0051 3.2 29 0233 1.1 0706 0.8 0809 2.5 0706 1.2 0842 2.9 Sa 1315 3.3 Su 1401 1.6 M 1315 3.3 Tu 1453 1.2 1930 0.9 2018 2.8 1929 1.2 2107 3.3 6 0136 3.2 14 0259 1.4 22 0132 3.2 30 0335 1.0 0749 .1.0 0902 2.6 0741 1.3 0945 3.1 Su 1358 3.2 M 1456 1.5 Tu 1352 3.3 W 1556 1.1 2018 1.1 2105 2.9 2013 1.2 2205 3.4

7 0223 3.0 15 0342 1.3 23 0215 3.1 31 0429 0.9 0832 1.1 0945 2.7 0819 1.3 1039 3.3 M 1440 3.2 Tu 1541 1.4 W 1434 3.3 Th 1650 1.0 2107 1.2 2146 3.0 2101 1.3 2257 3.5,

80311 2.9 16 0419 1.2 24 0303 2.9 0914 1.3 1024 2.8 0901 1.4 Tu 1525 3.1 W 1620 1.4 Th 1523 3.2 2159 1.3 2223 3.1 2157 1.3 TOGA SEA LEVEL CENTER University of Hawaii, 1000 Pope Road, MSB 430 Honolulu, Hawaii, 96822, USA. HIGH AND LOW WATERPREDICTIONS FOR Rarotonga LAT:2112S LONG:159 46W, local time, heights in feet

NOTE: These tide predictions are based on data collected between May 1987 and June 1988. The mean sea level during this period was 1.86 feet. The datum for these tide predictions is the zero point of the tide staff at Avarua Harbour, Rarotonga Cook Island established in 1977. Please note that the quoted values are not related to chart datum and should be used with caution.

FEBRUARY 1991

Time Feet Time Feet Time Feet Time Feet

1 0516 0 .9 9 0503 2.6 17 0534 1.3 25 0558 2-.8 1126 3.5 1048 1.8 1140 3.5 1204 1.6 F 1738 0.9 Sa 1726 2.8 Su 1751 1.2 M 1840 3.1 2344 3.5 2354 3.5

2' 0600 0.9 10 0019 1.7 18 0607 1.3 26 0111 1.4 1208 3.6~ 0614 2.5 1214 3.6 0721 2.8 Sa 1823 1.0 Su 1200 1.9 M 1830 1.2 Tu 1337 1.5 1838 2.8 1957 3.2

3 0028 3.5 11 0127 1.7 19 0032 3.4 27 0222 1.3 0640 1.0 0727 2.6 0641 1.3 0833 3.0 Su 1248 3.6 M 1320 1.8 Tu 1250 3.6 W 1450 1.4 1906 1.0 1944 2.9 1910 1.2 2101 3.3

4 0109 3.4 12 0225 1.6 20 0112 3.4 28 0322 1.2 0718 1.1 0829 2.7 0716 1.3 0932 3.2 M 1325 3.5 Tu 1427 1.8 W 1328 3.6 Th 1547 1.2 1947 1.2 2037 2.9 1953 1.2 2155 3.4

5 0150 3.2 13 0311 1.6 21 0154 3.2 0755 1.3 0916 2.8 0754 1.3 Tu 1403 3.4 W 1517 1.6 Th 1410 3.5 2030 1.3 2122 3.1 2040 1.3

6 0231 3,.1 14 0351 1.5 22 0240 3.1 0831 1.4 0956 3.0 0838 1.4 W 1442 3.3 Th 1558 1.5 F 1500 3.4 2115 1.5 2201 3.2 2135 1.4 7 0314 2.9 ~ 15 0427 1.4 23 0334 2.9 0910 1.6 1032 3.2 0930 1.5 Th 15263.1 F 1636 1.4 Sa 1601 3.2 2207 1.6 2239 3.3 2240 1.4

8 0403 2.7 16 0500 1.4 24 0439 2.8 0953 1.7 1106 3.4 1037 1.6 F 1620 2.9 Sa 1713 1.3 Su 1717 3.1 2309 1.7 2316 3.4 2354 1.5'"

[c;~"". TOGA SEA LEVEL CENTER University of Hawaii, 1000 Pope Road, MSB 430 Honolulu, Hawaii, 96822, USA.

HIGH AND LOW WATERPREDICTIONS FOR Rarotonga LAT:21 12S LONG:159 46W, local time, heights in feet

NOTE: These tide predictions are based on data collected between May 1987 and June 1988. The mean sea level during this period was 1.86 feet. The datum for these tide predictions is the zero point of the tide staff at Avarua Harbour, Rarotonga Cook Island established in 1977. Please note that the quoted values are not related to chart datum and should be used with caution.

MARCH 1991

~ Time Feet Time Feet Time Feet Time Feet ~ L' 0412 1.1 9 0319 2.7 17 0428 1.4 _25 0430 2,8 1020 3.4 0910 1.6 1033 3.4 1039 1.5 F 1635 1.1 Sa 1531 2.9 Su 1649 1.1 M 1714 3.0 2241 3.5 2217 1.6 2252 3.4 2341 1.5

2 0455 1.1 10 0412 2.6 18 0503 1.3 ~ 26 0549 2.8 1102 3.6 1001 1.7 1109 3.6 1209 1.5 Sa 1719 1.0 Su 1633 2.8 M 1728 1.0 Tu 1836 2.9 2323 3.5 2321 1.7 2332 3.4 3 0535 1.1 11 0518 2.5 19 0539 1.2 l 27 0056 1.5 1141 3.6 1109 1.8 1147 3.7 0709 2.9 Su 1759 1.0 M 1747 2.7 Tu 1809 1.0 W 1334 1.4 1948 3.0

4 0003 3;5 12 0030 1.7 20 0012 3.4 28 0203 1.4 II 0612 1.1 0634 2.6 0617 1.1 0815 -3.0 rr M 1217 3.6 Tu 1235 1.8 W 1226 3.7 Th 1439 1.3 1838 1.0 1900 2.7 1851 1.0 2047 3.1 5 0041 3.4 13 0133 1.7 L 21 0054 3.3 29 0259 1.3 0646 1.2 0742 2.7 H 0656 1.1 ~ 0908 3.2 11 Tu 1252 3.5 W 1350 1.8 '- Th1308 3.6 F 1530 1.1 1917 1.1 2001 2.9 H 1936 1.0 2136 3.2 ,~ 6 0118 3.2 14 0227 1.6 L 22 0138 3.2 Y3()! 0347 1.2 0720 i.3 0834 2.9 H 0738 1.2 L '- 0953 3.3 W 1327 3.4 Th 1445 1.6 L F 1354 3.4 Sa 1614 1.0 1956 1.3 2051 3.0 H 2026 1.1 2219 3.3

7 0156 3.0 15 0312 1.6 L 23 0227 3.0 31 0429 1.1 0754 1.4 0917 3.1 H 0827 1.3 1034 3.4 Th 1403 3.2 F 1529 1.4 Sa 1448 3.3 Su 1655 0.9 2037 1.4 "--- 2133 3.2 # 2122 1.3 2259 3.3 "" 8 0235 2.9 ~ 16'0351 1.5 24 0323 2.9 0829 1.5 0956 3.3 0925 1.4 F 1443 3.1 Sa 1610 1.3 Su 1554 3.1 2123 1.5 2213 3.3 2228 1.4 . TOGA SEA LEVEL CENTER v University of Hawaii, 1000 Pope Road, MSB 430 Honolulu, Hawaii, 96822, USA. HIGH AND LOW WATERPREDICTIONS FOR Rarotonga LAT:21 12S LONG:159 46W, local time, heights in feet NOTE: These tide predictions are based on data collected between May 1987 and June 1988. The mean sea level during this period was 1.86 feet. The datum for these tide predictions is the zero point of the tide staff at Avarua Harbour, Rarotonga Cook Island established in 1977. Please note that the quoted values are not related to chart datum and should be used with caution.

APRIL 1991

Time Feet Time Feet Time Feet Time Feet

1 0506 1.1 9 0432 2.5 17 0513 0.9 25 0030 1.3 1111 3.4 \~ 1032 1.6 \ 1122 3.5 0646 2.8 M 1734 0:9 Tu 1658 ~:~ W 1749 0.6 Th 1317 1.2 2337 3.2 2329 1.6 2353 3.2 1928 2.8

20542 1.1 10 0539 2.5 18 0556 0.9 26 0132 1.3 1147 3 .41) --~ ~ ~ ~ ~ .~l. .1207 3 .5 074 6 2 .9 Tu 1812 0.9. W 1811 2.6 Th 1835 0.7 F 1416 1.1 2023 2.9 3 0014 3.1 11 0032 1.6 19 0040 3.1 27 0227 1.3 0616 1.1 0646 2.6 0642 0.9 0837 3.0 W 1221 3.3 Th 1305 1.5 F 1255 3.4 Sa 1505 1.0 1849 1.0 1917 2.7 1924 0.8 21l0 -2.9

4 0051 3.0 12 0130 1.5 20 0129 3.0 28 0315 1.2 0649 1.1 0743 2.8 0732 1.0 0922 3.1 Th 1255 3.1 F 1405 1.4 Sa 1347 3.2 Su 1550 0.9 1926 1.1 2011 2.8 2017 0.9 2154 2.9

5 0128 2.8 13 0221 1.5 21 0221 2.9 V 29 0358 1.1 0723 1.2 0831 3.0 0827 1.1 ' 1004 3.1 F 1331 3.0 Sa 1453 1.2 Su 1446 3.0 M 1631 0.8 2004 1.2 2058 2.9 2115 1.1 2234 2.9

6 0206 2.7 14 0307 1.3 22 0319 2.8 30 0438 1.0 0759 1~3 0914 3.2 0931 1.2 1042 3.1 Sa 1409 2.9 Su 1537 1.0 M 1554 2.9 Tu 1710 0.8 2045 1.3 --_2142 3.1 2218 1.2 2313 2.8 / \ /' 7 0247 2.6 I~\ 15 0349 1.2 23 0424 2.7 0839 1.4 0957 3.3 1045 1.3 Su 1453 2.7 M 1621 0.8 Tu 1709 2.8 2132 1.4 2225 3.1 2325 1.3

8 0334 2.5 16 0431 1.0 24 0537 2.7 0929 1.5 1039 3.5 1205 1.3 M 1549 2.6 Tu 1704 0.7 W 1823 2.8 2227 1.5 2308 3.2 APPENDIX B

Notes on Data Analysis Methods

by

Malcolm Greig New Zealand Oceanographic Institute NEW ZEALAND DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH

31 January 1992

BrendanHolden Coastal/OceanographyEngineer SOPAC Private Bag, SuvaE!Jl

Dear Brendan

Enclosedare the plots and tidal analysesfor the secondset of data. They consistof :

1) Time seriesplot of the data as recordedafter despiking etc. for eachcurrent meterand the tide gauge.

2) Progressivevector plot for eachcurrent series.

3) Currentrose for each current series.

4) Plot of filtered data. For theseplots the data was filtered using a low pass filter to remove the mainly tidal currents with periods less than about 30 hours. Then the longer period data was plotted as 'filtered current'. Also plotted is the short period currents which were obtainedby subtractingthe longerperiod flow from the original data. This later data set is labelled 'Tidal Flow' but it also includes all short period flows which are not due to the astronomicaltides.

5) Hannonic analysesfor eastand north componentcurrent and for the waterlevel data. These show that the astronomicaltides are small in this area with the strongest constituentMz having an elevation amplitude of 0.257 meters in the Avarua water level record.

6) Tidal current ellipse parameters for the constituents O1' K1, Mz, N2, and 82. The ellipse parameters show that the tidal cun-ents are only a small part of the total flow. The strongest tidal flow is due to M2 with an amplitude of 8.9 cm S.1in the top current meter record from Motutoa.

Comparing the phase lag of the Mz tide in the top current meter record from Motutoa (Phase of maximum flow with northward component PHA = 97) with the elevation phase lag at Avarua (210.4) we note that for this dominant tidal constituent tidal flow

Evans Bay Road, Greta Point, PO Box 14901,Xilbirnie, Wellington, New Zealand 6003 Telephone (04) 3861189, Facsimile (04) 386 2153 in the direction 285" (ORE n - the orientation of the major axis of the tidal ellipse with a northward direction) leads the elevation by 210 - 97 = 113 degrees. Conversely flow toward 105" lags the elevation by 67 degrees. Thus maximum flow toward 105' will lag high tide in the M constituent by 67/360 * 360/28.98 = 2.3 hours.

While the regular tidal currents are small the plots show short duration currents to the west of almost 100 cm s. These seem to occur most often on the rising tide but as to what drives them I don't know. I have had a quick look through our library for some published information but could not find anything useful. I imagine you have access to the Pacific Islands Pilot but in case not I note that it reports a current which sets west across Avatiu Harbour at rates from 1 to 3 knots (50 - 150 cm s) except after prolonged northerly winds when there is little current,

Comparing tidal elevation at Avarua and Muri the phase lag for the M constituent at Avarua is 210.4' and at Muri is 234.3'. This gives a delay of (234.3 - 210.4)/28.98 hours or 50 minutes. Many of the other constituents also show a delay at Muri behind Avarua.

Regarding your query on maximum flows there is nothing reliable that can be done with such a short record especially in light of the brief strong currents which occur. Tropical storms are likely to cause the strongest currents and swell, and these events may be the prime concern for the sewer pipe.

I realise that you will quite likely have a better understanding of many of these issues than myself but I have included the comments in case they are of some use to you.

Yours Sincerely,

Malcolm Greig ******** T.I.R.A. (G.P.) ******** OATAINPUT FROM FILE: avaruwlr.hPT DCt\.~ .(1-,1~ ~ ~".Atj ~ ,'S'- Alignment(deg.): 0--=- ~ ~

INITIAL OBS 20.1 79 1991 FINAL OBS 19.1 114 1991 OBS M= 0.10070+01 So= 0.21190+00 RES M=-0.85850-07 So= 0.39940-01

RELATEOCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0014 123.645

2 P1 K1 14.9589314 0.0241 123.645 3 PSI1 K1 15.0821353 0.0006 123.645 4 PHIl K1 15.1232059 0.0010 123.645 5 2N2 N2 27.8953548 0.0079 178.222 6 NU2 N2 28.5125831 0.0116 178.222 7 T2 S2 29.9589333 0.0048 304.666 8 K2 S2 30.0821373 0.0221 304.666

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 1.0056 0.000 2 MM 0.5443747 0.0208 77.580 3 MSF 1.0158958 0.0210 345.725 4 Q1 13.3986609 0.0048 95.715 5 01 13.9430356 0.0238 62.452 6 K1 15.0410686 0.0727 123.645 7 J1 15.5854433 0.0067 128.360 8 001 16.1391017 0.0043 84.675 9 MU2 27.9682084 0.0070 173.939 10 N2 28.4397295 0.0596 178.222 11 M2 28.9841042 0.2566 210.400 12 L2 29.5284789 0.0027 10.771 13 S2 30.0000000 0.0814 304.666 14 M03 42.9271398 0.0039 10.910 15 M3 43.4761563 0.0028 330.360 16 MK3 44.0251729 0.0059 188.865 17 MN4 57.4238337 0.0005 218.987 18 M4 57.9682084 0.0064 4.624 19 SN4 58.4397295 0.0011 161.303 20 MS4 58.9841042 0.0042 96.967 21 2MN6 86.4079380 0.0010 154.747 22 M6 86.9523127 0.0043 189.314 23 2MS6 87.9682084 0.0040 224.120 24 2SM6 88.9841042 0.0016 310.927

t \ ~~S;l. lCL3-c.t~.s:.

, ~l, hcA.~ ~ IV\ ******* T. I.R.A. (G.S.) ********

OATA INPUT FROMFILE: muri-wlr.hPT Alignment (deg.): 0

INITIAL OBS 21.8 344 1990 FINAL OBS 20.8 14 1991 OBS M= 0.96410+00 So= 0.19750+00 RES M= 0.91600-04 So= 0.14160+00

RELATEOCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0005 92.557

2 P1 K1 14.9589314 0.0083 92.557 3 PSI1 K1 15.0821353 0.0002 92.557 4 PHIl K1 15.1232059 0.0004 92.557 5 2N2 N2 27.8953548 0.0029 203.872 6 NU2 N2 28.5125831 0.0043 203.872 7 T2 S2 29.9589333 0.0035 293.937 8 K2 S2 30.0821373 0.0161 293.937

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 0.9583 0.000 2 MM 0.5443747 0.0168 79.846 3 MSF 1.0158958 0.0385 268.466 4 Q1 13.3986609 0.0108 197.131 5 01 13.9430356 0.0233 125.589 6 K1 15.0410686 0.0252 92.557 7 J1 15.5854433 0.0125 111.661 8 001 16.1391017 0.0060 270.648 9 MU2 27.9682084 0.0053 23.509 10 N2 28.4397295 0.0220 203.872 11 M2 28.9841042 0.1841 234.261 12 L2 29.5284789 0.0073 22.200 13 S2 30.0000000 0.0592 293.937 14 M03 42.9271398 0.0077 162.210 15 M3 43.4761563 0.0124 90.972 16 MK3 44.0251729 0.0064 46.452 17 MN4 57.4238337 0.0131 338.970 18 M4 57.9682084 0.0173 29.038 19 SN4 58.4397295 0.0109 208.490 20 MS4 58.9841042 0.0226 164.949 21 2MN6 86.4079380 0.0070 260.573 22 M6 86.9523127 0.0107 217.467 23 2MS6 87.9682084 0.0103 213.052 24 2SM6 88.9841042 0.0054 56.354 Output from ellipse. 31-JAN-92

PHA = Phase of max. flow with northward component V = Northward speed at max. flow D = max flow ORE = Orientation degrees true of major axis

Input from: avarutop

U GAMI V PHII Const. E PHO PHA V D ORE ORE n 1.59 267.5 0.07 325.0 01 0.04 1. 267. 0.0 1.6 89. 89. 2.62 15.2 0.46 196.3 K1 0.00 350. 195. 0.5 2.7 100. 280. 1.76 240.8 0.40 20.5 N2 0.14 350. 59. 0.3 1.8 100. 280. 0.37 216.8 0.98 264.7 M2 0.26 75. 261. 1.0 1.0 15. 15. 1.02 243.4 0.53 99.2 82 -0.26 335. 70. 0.5 1.1 115. 295.

Input from: avarubot

U GAMI V PHII Const. E PHO PHA V D ORE ORE n 0.64 222.5 0.09 38.9 01 0.01 352. 42. 0.1 0.6 98. 278. 0.95 344.0 0.06 289.6 K1 -0.05 2. 344. 0.0 0.9 88. 88. 1.49 242.0 0.43 77.8 N2 -0.07 344. 63. 0.4 1.5 106. 286. 0.96 202.7 0.30 19.4 M2 0.02 343. 22. 0.3 1.0 107. 287. 0.67 222.1 0.13 17.9 82 0.08 350. 41. 0.1 0.7 100. 280.

Input from: motuttop

U GAMI V PHII Const. E PHO PHA V D ORE ORE n 0.36 23.8 0.25 271.6 01 -0.58 337. 217. 0.1 0.4 113. 293. 1.93 8.9 0.47 147.0 K1 0.16 349. 187. 0.4 2.0 101. 281. 3.01 164.8 0.91 320.7 N2 0.11 344. 343. 0.8 3.1 106. 286. 8.60 278.1 2.28 85.1 M2 0.06 345. 97. 2.2 8.9 105. 285. 1.65 179.8 0.39 8.2 82 -0.03 167. O. 0.4 1.7 283. 283.

Input from: motutbot

U GAMI V PHII Const. E PHO PHA V D ORE ORE n 0.62 307.5 0.13 216.6 01 -0.21 360. 127. 0.0 0.6 90. 270. 1.30 20.9 0.20 182.5 K1 0.05 351. 201. 0.2 1.3 99. 279. 1.45 158.7 0.37 344.0 N2 -0.02 346. 339. 0.4 1.5 104. 284. 5.80 274.6 1.64 93.6 M2 0.00 344. 95. 1.6 6.0 106. 286. 1.13 179.6 0.45 1.2 82 -0.01 158. 360. 0.5 1.2 292. 292.

t l'

Pt-:,_.~I._.,,"'- e~~; PhQ.te.. \ Q..CJ0"- +-low I~ ~t ol,'r-tc.h~

\~~(CtJ:-t..cA b\./ OA..~""

D l'.r .t p-e.~ t>.f- tu.rr-W ~f M.~)t:". .t..tOW ,'",,- ~M /5". ******** T. I .R.A. (G.P.) ********

DATA INPUT FROMFILE: avarubot.xPT Alignment (deg.): 90

INITIAL OBS 22.3 29 1991 FINAL OBS 21.3 64 1991 OBS M=-0.4229D+00 SD= 0.4144D+01 RES M= 0.3489D-07 SD= 0.3763D+01

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0180 344.040

2 P1 K1 14.9589314 0.3133 344.040 3 PSI1 K1 15.0821353 0.0076 344.040 4 PHIl K1 15.1232059 0.0133 344.040 5 2N2 N2 27.8953548 0.1981 242.044 6 NU2 N2 28.5125831 0.2890 242.044 7 T2 S2 29.9589333 0.0397 222.122 8 K2 S2 30.0821373 0.1832 222.122

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 0.4290 180.000 2 MM 0.5443747 0.3459 213.811 3 MSF 1.0158958 0.3767 35.846 4 Q1 13.3986609 0.5420 0.967 5 01 13.9430356 0.6375 222.468 6 K1 15.0410686 0.9465 344.040 7 J1 15.5854433 0.2427 28.962 8 001 16.1391017 0.1362 171.919 9 MU2 27.9682084 0.5300 319.303 10 N2 28.4397295 1.4897 242.044 11 M2 28.9841042 0.9593 202.720 12 L2 29.5284789 0.1633 220.063 13 S2 30.0000000 0.6735 222.122 14 M03 42.9271398 0.1331 239.857 15 M3 43.4761563 0.2127 353.977 16 MK3 44.0251729 0.4401 63.902 17 MN4 57.4238337 0.1742 143.023 18 M4 57.9682084 0.2815 171.216 19 SN4 58.4397295 0.2142 318.099 20 MS4 58.9841042 0.2075 40.350 21 2MN6 86.4079380 0.4176 249.790 22 M6 86.9523127 0.2387 162.893 23 2MS6 87.9682084 0.2451 92.663 24 2SM6 88.9841042 0.0034 128.323 ******** T. I.R.A. (G.P.) ********

DATA INPUT FROMFILE: avarutop.xPT Alignment (deg.): 90

INITIAL OBS 22.3 29 1991 FINAL OBS 21.3 64 1991 OBS M= 0.9781D+00 SD= 0.6759D+01 RES M=-0.1326D-07 SD= 0.5978D+01

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONSTI PI1 CONSTK1 14.9178647 0.0498 15.151

2 PI K1 14.9589314 0.8667 15.151 3 PSI1 K1 15.0821353 0.0209 15.151 4 PHIl K1 15.1232059 0.0367 15.151 5 2N2 N2 27.8953548 0.2341 240.774 6 NU2 N2 28.5125831 0.3414 240.774 7 T2 S2 29.9589333 0.0602 243.429 8 K2 S2 30.0821373 0.2775 243.429

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

I ZO 0.0000000 0.9744 0.000 2 MM 0.5443747 0.8778 301.817 3 MSF 1.0158958 1.3475 14.630 4 Q1 13.3986609 1.4117 354.934 5 01 13.9430356 1.5858 267.458 6 K1 15.0410686 2.6185 15.151 7 J1 15.5854433 0.5797 352.881 8 001 16.1391017 0.4638 113.635 9 MU2 27.9682084 0.9644 350.650 10 N2 28.4397295 1.7599 240.774 11 M2 28.9841042 0.3724 216.795 12 L2 29.5284789 0.1362 195.893 13 S2 30.0000000 1.0201 243.429 14 M03 42.9271398 0.5340 223.232 15 M3 43.4761563 0.2777 15.825 16 MK3 44.0251729 0.3867 168.929 17 MN4 57.4238337 0.4311 176.550 18 M4 57.9682084 0.4016 53.596 19 SN4 58.4397295 0.4272 73.594 20 MS4 58.9841042 0.3460 157.985 21 2MN6 86.4079380 0.1762 308.506 22 M6 86.9523127 0.4507 224.571 23 2MS6 87.9682084 0.3166 147.176 24 2SM6 88.9841042 0.3792 152.290 ******** T.I.R.A. (G.P.) ********

DATA INPUT FROMFILE: motutbot.xPT Alignment (deg.): 90

INITIAL OBS 20.8 78 1991 FINAL OBS 19.8 113 1991 OBS M=-0.3961D+01 SD= 0.8295D+01 RES M= 0.2027D-06 SD= 0.6656D+01

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0248 20.926

2 P1 K1 14.9589314 0.4313 20.926 3 PSI1 K1 15.0821353 0.0104 20.926 4 PHIl K1 15.1232059 0.0182 20.926 5 2N2 N2 27.8953548 0.1930 158.748 6 NU2 N2 28.5125831 0.2815 158.748 7 T2 S2 29.9589333 0.0670 179.626 8 K2 S2 30.0821373 0.3087 179.626

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 3.7198 180.000 2 MM 0.5443747 1.7260 154.593 3 MSF 1.0158958 1.8653 259.793 4 Q1 13.3986609 1.0358 292.349 5 01 13.9430356 0.6194 307.485 6 K1 15.0410686 1.3030 20.926 7 J1 15.5854433 0.5953 85.082 8 001 16.1391017 0.0811 316.224 9 MU2 27.9682084 0.5420 238.012 10 N2 28.4397295 1.4512 158.748 11 M2 28.9841042 5.8042 274.601 12 L2 29.5284789 0.9208 164.224 13 S2 30.0000000 1.1349 179.626 14 M03 42.9271398 0.2347 36.927 15 M3 43.4761563 0.2567 135.236 16 MK3 44.0251729 0.3636 37.516 17 MN4 57.4238337 0.3992 34.227 18 M4 57.9682084 0.4714 255.365 19 SN4 58.4397295 0.5960 158.459 20 MS4 58.9841042 0.4933 133.974 21 2MN6 86.4079380 0.1457 272.217 22 M6 86.9523127 0.3590 120.931 23 2MS6 87.9682084 0.5155 188.578 24 2SM6 88.9841042 0.2550 162.417 ******** T.I.R.A. (G.P.) ********

DATA INPUT FROMFILE: avarubot.yPT Alignment (deg.): 0

INITIAL OBS 22.3 29 1991 FINAL OBS 21.3 64 1991 OBS M=-0.32440+00 so= 0.24910+01 RES M= 0.35110-07 so= 0.24130+01

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0012 289.561

2 P1 K1 14.9589314 0.0203 289.561 3 PSI1 K1 15.0821353 0.0005 289.561 4 PHIl K1 15.1232059 0.0009 289.561 5 2N2 N2 27.8953548 0.0573 77.824 6 NU2 N2 28.5125831 0.0836 77.824 7 T2 S2 29.9589333 0.0080 17.862 8 K2 S2 30.0821373 0.0367 17.862

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 0.3799 180.000 2 MM 0.5443747 0.1916 104.767 3 MSF 1.0158958 0.2415 85.616 4 Q1 13.3986609 0.1836 115.103 5 01 13.9430356 0.0933 38.891 6 K1 15.0410686 0.0612 289.561 7 J1 15.5854433 0.1549 237.437 8 001 16.1391017 0.0502 246.138 9 MU2 27.9682084 0.1938 89.472 10 N2 28.4397295 0.4307 77.824 11 M2 28.9841042 0.2986 19.353 12 L2 29.5284789 0.2285 276.260 13 S2 30.0000000 0.1349 17.862 14 M03 42.9271398 0.0834 179.713 15 M3 43.4761563 0.0566 122.194 16 MK3 44.0251729 0.0465 313.051 17 MN4 57.4238337 0.0826 29.663 18 M4 57.9682084 0.0423 224.080 19 SN4 58.4397295 0.2256 360.000 20 MS4 58.9841042 0.3349 208.729 21 2MN6 86.4079380 0.1650 17.914 22 M6 86.9523127 0.1499 230.281 23 2MS6 87.9682084 0.0949 190.334 24 2SM6 88.9841042 0.1165 226.045 ******** T.I.R.A. (G.P.) ********

DATA INPUT FROMFILE: avarutop.yPT Alignment (deg.): 0

INITIAL OBS 22.3 29 1991 FINAL OBS 21.3 64 1991 OBS M=-0.5220D+00 SD= 0.4719D+01 RES M=-0.2798D-07 SD= 0.4465D+01

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0088 196.255

2 P1 K1 14.9589314 0.1539 196.255 3 PSI1 K1 15.0821353 0.0037 196.255 4 PHIl K1 15.1232059 0.0065 196.255 5 2N2 N2 27.8953548 0.0534 20.532 6 NU2 N2 28.5125831 0.0779 20.532 7 T2 S2 29.9589333 0.0315 99.189 8 K2 S2 30.0821373 0.1452 99.189

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 zo 0.0000000 0.4083 180.000 2 MM 0.5443747 0.4604 246.941 3 MSF 1.0158958 0.5955 298.499 4 Q1 13.3986609 0.3286 159.758 5 01 13.9430356 0.0722 325.002 6 K1 15.0410686 0.4648 196.255 7 J1 15.5854433 0.4003 217.034 8 001 16.1391017 0.3982 259.143 9 MU2 27.9682084 0.2296 176.792 10 N2 28.4397295 0.4018 20.532 11 M2 28.9841042 0.9817 264.744 12 L2 29.5284789 0.3663 92.865 13 S2 30.0000000 0.5340 99.189 14 M03 42.9271398 0.2171 189.180 15 M3 43.4761563 0.7381 82.247 16 MK3 44.0251729 0.4297 253.304 17 MN4 57.4238337 0.2137 195.319 18 M4 57.9682084 0.3511 25.828 19 SN4 58.4397295 0.1595 237.020 20 MS4 58.9841042 0.3260 193.652 21 2MN6 86.4079380 0.4761 41.263 22 M6 86.9523127 0.6977 332.322 23 2MS6 87.9682084 0.2794 154.112 24 2SM6 88.9841042 0.3518 269.999 ******** T. I .R.A. (G.P.) ********

DATA INPUT FROMFILE: motutbot.yPT Alignment (deg.): 0

INITIAL OBS 20.8 78 1991 FINAL OBS 19.8 113 1991 OBS M= 0.1532D+01 SD= 0.2857D+01 RES M=-0.4438D-08 SD= 0.24780+01

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0039 182.485

2 P1 K1 14.9589314 0.0679 182.485 3 PSI1 K1 15.0821353 0.0016 182.485 4 PHIl K1 15.1232059 0.0029 182.485 5 2N2 N2 27.8953548 0.0494 344.030 6 NU2 N2 28.5125831 0.0720 344.030 7 T2 S2 29.9589333 0.0268 1.205 8 K2 S2 30.0821373 0.1237 1.205

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 1.5064 0.000 2 MM 0.5443747 0.3818 306.087 3 MSF 1.0158958 0.5297 78.013 4 Q1 13.3986609 0.3190 108.872 5 01 13.9430356 0.1287 216.616 6 K1 15.0410686 0.2050 182.485 7 J1 15.5854433 0.1062 269.280 8 001 16.1391017 0.1411 130.538 9 MU2 27.9682084 0.1807 337.683 10 N2 28.4397295 0.3712 344.030 11 M2 28.9841042 1.6447 93.598 12 L2 29.5284789 0.1667 315.625 13 S2 30.0000000 0.4547 1.205 14 M03 42.9271398 0.0279 283.368 15 M3 43.4761563 0.1568 330.367 16 MK3 44.0251729 0.2208 187.698 17 MN4 57.4238337 0.1399 338.754 18 M4 57.9682084 0.0553 29.308 19 SN4 58.4397295 0.3092 325.757 20 MS4 58.9841042 0.1370 343.945 21 2MN6 86.4079380 0.1621 102.874 22 M6 86.9523127 0.1026 294.386 23 2MS6 87.9682084 0.1156 320.822 24 2SM6 88.9841042 0.1117 51.118

j ******** T. I .R.A. (G.P.) ********

DATA INPUT FROMFILE: motuttop.xPT Alignment (deg.): 90

INITIAL OBS 20.8 78 1991 FINAL OBS 19.8 113 1991 OBS M=-0.5549D+01 SD= 0.1337D+02 RES M= 0.2027D-06 SD= 0.1121D+02

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0367 8.910

2 P1 K1 14.9589314 0.6399 8.910 3 PSI1 K1 15.0821353 0.0155 8.910 4 PHIl K1 15.1232059 0.0271 8.910 5 2N2 N2 27.8953548 0.4009 164.771 6 NU2 N2 28.5125831 0.5847 164.771 7 T2 S2 29.9589333 0.0975 179.810 8 K2 S2 30.0821373 0.4493 179.810

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 5.2846 180.000 2 MM 0.5443747 1.6978 207.363 3 MSF 1.0158958 2.3253 259.993 4 Q1 13.3986609 1.4911 286.906 5 01 13.9430356 0.3640 23.762 6 K1 15.0410686 1.9333 8.910 7 J1 15.5854433 1.0517 83.767 8 001 16.1391017 0.5709 321.382 9 MU2 27.9682084 0.8653 238.503 10 N2 28.4397295 3.0142 164.771 11 M2 28.9841042 8.6013 278.082 12 L2 29.5284789 1.6300 172.923 13 S2 30.0000000 1.6519 179.810 14 M03 42.9271398 0.5789 100.318 15 M3 43.4761563 0.5071 206.131 16 MK3 44.0251729 0.9015 81.418 17 MN4 57.4238337 0.6423 51.840 18 M4 57.9682084 0.9641 288.426 19 SN4 58.4397295 1.2194 158.129 20 MS4 58.9841042 0.6042 155.512 21 2MN6 86.4079380 0.0471 259.317 22 M6 86.9523127 0.4236 143.608 23 2MS6 87.9682084 0.6695 217.691 24 2SM6 88.9841042 0.3003 193.024

, ******** T. I.R.A. (G.P.) ********

DATA INPUT FROMFILE: motuttop.yPT Alignment (deg.): 0

INITIAL OBS 20.8 78 1991 FINAL OBS 19.8 113 1991 OBS M= 0.1454D+01 SD= 0.4137D+01 RES M=-0.6878D-08 SD= 0.3644D+01

RELATEDCONSTITUENTS

NO REL REF SPEED H G --CONST1 PI1 CONSTK1 14.9178647 0.0090 147.035

2 P1 K1 14.9589314 0.1567 147.035 3 PSI1 K1 15.0821353 0.0038 147.035 4 PHIl K1 15.1232059 0.0066 147.035 5 2N2 N2 27.8953548 0.1207 320.705 6 NU2 N2 28.5125831 0.176.1 320.705 7 T2 S2 29.9589333 0.0231 8.220 8 K2 S2 30.0821373 0.1067 8.220

MAJORCONSTITUENTS NSIG= 24

NO NAME SPEED H G

1 ZO 0.0000000 1.3959 0.000 2 MM 0.5443747 0.4694 45.831 3 MSF 1.0158958 0.5168 79.804 4 Q1 13.3986609 0.2966 144.397 5 01 13.9430356 0.2523 271.573 6 K1 15.0410686 0.4735 147.035 7 J1 15.5854433 0.4283 244.049 8 001 16.1391017 0.2914 132.191 9 MU2 27.9682084 0.1745 15.443 10 N2 28.4397295 0.9077 320.705 11 M2 28.9841042 2.2797 85.141 12 L2 29.5284789 0.4843 350.939 13 S2 30.0000000 0.3924 8.220 14 M03 42.9271398 0.1999 324.538 15 M3 43.4761563 0.3491 51.365 16 MK3 44.0251729 0.2639 195.906 17 MN4 57.4238337 0.1576 292.057 18 M4 57.9682084 0.2087 109.441 19 SN4 58.4397295 0.5496 312.557 20 MS4 58.9841042 0.1939 335.003 21 2MN6 86.4079380 0.1325 22.715 22 M6 86.9523127 0.0427 2.646 23 2MS6 87.9682084 0.2558 67.422 24 2SM6 88.9841042 0.2632 10.978

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