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Revised
Measuring-Point Elevations for Selected Wells in the Waihee and Iao Aquifer
Areas on the Island of Maui
The USGS has been
working with the National Geodetic Survey (NGS) to update benchmark and well
measuring-point elevations in central Maui as part of a ground-water
availability study with the Maui Department of Water Supply. The purpose of
this effort is to ensure that water-level monitoring wells used in this study
are tied to a common and accurate vertical datum.
Benchmark
and reference-mark elevations were determined by the NGS using differential
GPS (Global Positioning System) methods during September 2-4, and November
18-20, 2003.
Well
measuring-point elevations were determined by the USGS using vertical
leveling surveys from NGS benchmarks and USGS reference marks during
September 22-26, and December 15-19, 2003.
Measuring-point
elevations for selected wells in the Waihee and Iao aquifer areas are
provided below. The difference between the previously reported and the
revised measuring-point elevation for each well is also provided. Leveling
notes and photographs of the measuring points are available in well folders
maintained by the USGS Water Resources office in Honolulu.
It is important to
recognize that the revised well measuring-point elevations will result in a
modification of the absolute water levels (referenced to mean sea level), but
not the relative change in water levels measured over time (trend).
Historical water levels
measured in these wells may be revised pending further research into possible
causes for the differences between the previously reported and the revised
well measuring-point elevations. Future water-level measurements will be
based on the revised well measuring-point elevations.
An additional set of measuring-point
elevations were updated to provide a common datum for a synoptic water-level
survey conducted on May 17, 2005. Benchmark and reference-mark elevations
were determined by the NGS using differential GPS (Global Positioning System)
methods during May 10-12, 2005. Well measuring-point elevations were
determined by the USGS using vertical leveling surveys from NGS benchmarks
and USGS reference marks during September 19-23, September 26-28, and
November 29 - December 1, 2005. A second table of the additional measuring-point
elevations is provided below.
Related links:
Ground-Water Availability in Central Maui -
Project description
Recent Hydrologic Conditions, Iao Aquifer area,
Maui - Updated every three months
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Well
measuring-point elevations, in feet above mean sea level, for selected
wells in the Waihee and Iao aquifer areas on Maui
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Released
January 6, 2004; Updated May 21, 2004 using final NGS benchmark elevations.
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[RM, reference
mark; MP, measuring point; ft, feet; --, no data]
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Well
name
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State well number
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Revised1
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Previous
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Difference2
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Notes
regarding previous well measuring-point elevations 3
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Kupaa 1
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5731-03
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638.77
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639.37
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-0.60
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C.
Takumi Engineering report (1/31/00) provides MP elevation of 639.37 ft for
top of casing, based on leveling from a benchmark elevation of 631.87 ft
located about 200 ft from well (Exhibit A-1, Mink & Yuen, 6/21/99).
Driller's well-completion report provides MP elevation of 638.10 ft for top
of casing (5/20/99). No record of MP survey notes and initial benchmark. Wailani Drilling and Ed Valera
(surveyor) combined trigonometric leveling (using a total station and
vertical angles) from Tanaka's work and a carpenter's level to get the
initial height of casing.
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Kanoa
TH
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5731-05
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303.56
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305.22
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-1.66
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USGS
reports MP elevation of 305.22 ft for top of casing, based on leveling from
nearby RM - 1-inch pipe (1/22/03). RM elevation of 304.50 ft provided by C.
Takumi Engineering. No record of RM survey notes and initial benchmark. K.
Tanaka set the 1/2-in. pipe using trigonometric leveling (using a total
station and vertical angles).
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Kanoa 1
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5731-02
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308.14
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--
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--
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Driller's
well-completion report has elevation of 309.15 ft for top of pump base
plate (5/29/99). No record of MP survey or initial benchmark.
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Kanoa 2
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5731-04
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280.48
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--
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--
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Driller's
well-completion report has MP elevation 281.83 ft for top of sounding tube
(6/7/00). C. Takumi Engineering report (Aug. 2000) has 281.38 ft for top of
sounding tube (Exhibit A, Mink & Yuen, 7/12/00).
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North
Waihee 1
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5631-02
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283.76
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285.23
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-1.47
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USGS
reports MP elevation of 285.23 ft for top of measuring tube, based on
leveling from nearby RM - 3/4 inch pipe (8/12/97). RM elevation of 266.63
ft given by W.S. Unemori Engineering. No record
of RM survey notes and initial benchmark in well folder, however, Unemori confirms this elevation from their notes. From
information provided by Reed Ariyoshi of W.S. Unemori, and Wendy Taomoto,
MDWS, the best estimate of the difference between the top of the casing
prior to pump installation and the measuring tube after installation is
1.01 ft (old casing higher in elevation). As a result, the old mp for data
prior to August 1997, 284.78 ft, is very close to the new measuring tube
elevation plus 1.01 ft (284.77 ft).
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North
Waihee 2
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5631-03
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283.62
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--
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--
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Height
of measuring point modified after pump installation. Measuring tube
modified twice since pump installation in 1997 and leveling on 8/12/97.
USGS reports MP elevation of 284.39 ft for top of measuring tube on
8/12/97. USGS reports MP elevation of 284.33 ft for top of measuring tube
on 3/30/99 after first modification, based on measuring up from base plate
elevation of 284.11 ft. Previous leveling on 8/12/97 and 3/30/99 are based
on RM (3/4-inch pipe) elevation of 266.63 ft provided by W.S. Unemori Engineering. No record of RM survey notes and
initial benchmark in well folder, however, Unemori
confirms this elevation.
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Waihee
TH A1
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5631-01
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246.17
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248.05
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-1.88
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Driller's
well-completion report provides elevation of 248.05 ft for top of drilling
platform (10/15/74). Surveyed from State of Hawaii benchmark U-6: 250.37 ft
(1974). No record of survey notes.
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Waiehu
TH D
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5430-04
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380.95
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380.66
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0.29
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USGS
reports MP elevation of 380.66 ft for top of 1.75-inch PVC casing, based on
leveling from nearby RM - "X" chiseled in concrete at entrance to
TH D shelter (8/23/85). RM elevation of 380.01 ft provided by Dan Lum, DOWALD (8/29/83). No record of RM survey notes and
initial benchmark.
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Waiehu
Deep
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5430-05
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381.16
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380.84
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0.32
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USGS
reports MP elevation of 380.84 ft for top of 10-inch casing, based on
leveling from RM - "X" chiseled in concrete at entrance to TH D
shelter (8/23/85). RM elevation of 380.01 ft provided by Dan Lum, DOWALD (8/29/83). No record of RM survey notes and
initial benchmark.
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Waiehu
TH B
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5431-01
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492.15
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492.51
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--
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USGS
reports MP elevation of 492.51 ft for top of 1.5-inch PVC casing (9/24/75).
However, later field notes show top of casing as 491.79, and top of
surrounding wooden box as 492.51. No record of MP survey notes and initial
benchmark. Probably surveyed from State of Hawaii benchmark U-6: 250.37 ft
(1974). Driller's report provides elevation of 493.97 ft for top of
drilling platform. Well has been measured from top of wooden box since USGS
started measuring well in July, 1982. Well modified 3/31/04 by USGS, adding
0.74 ft to top of PVC casing. Revised MP (top of PVC casing) combines
changes due to recent surveying and modification. Elevation of top of box
was lowered by 0.42 ft from results of 2003/2004 surveying.
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Waiehu
Heights 2
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5430-02
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338.05
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--
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--
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Notes
in well folder show pump refurbishment in 1998. Measurement tube likely
installed at that time. No prior leveling notes or references in USGS well
folder.
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Waiehu
TH E
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5430-03
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415.65
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416.75
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-1.10
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Norman
Saito Engineering Consultants, Inc. provides MP elevation of 416.75 ft for
top of 1-inch casing (9/14/82). No record of MP survey notes and initial
benchmark. Probably surveyed from State of Hawaii benchmark U-6: 250.37 ft
(1974). Driller's report provides elevation of 415 ft for land surface.
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Mokuhau 1 (Pump 2) 4
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5330-09
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353.37
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353.79
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-0.42
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USGS
reports MP elevation of 353.79 ft (12/1/99). No record of MP survey and initial
benchmark. Dan Lum (DOWALD) provides MP elevation
of 353.57 ft for access port at base of pump (1/17/72). H.A.R. Austin
Engineering provides elevation of 353.17 ft for top of casing (6/4/53).
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Wailuku
Shaft 33
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5330-05
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32.33
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32.17
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0.16
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USGS
reports MP elevation of 32.17 ft for top of casing, based on leveling from
Wailuku Courthouse NGS benchmark elevation of 331.066 ft (4/17/97).
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Waikapu
1
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5130-01
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551.04
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551.33
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-0.29
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USGS
reports MP elevation of 551.33 ft for top of 6-inch coupling, based on
leveling from RM - 0.5 inch pipe located on the east side of the concrete
foundation (4/11/75). RM elevation of 550.61 ft provided by Norman Saito
Engineering, based on leveling from Wailuku Courthouse NGS benchmark
(12/74). Dan Lum (DOWALD) provides elevation of
552.08 ft for top of 8-inch casing, and 551.15 ft for top of conductor pipe
(5/14/74).
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Waikapu
2
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5130-02
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518.96
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519.33
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-0.37
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USGS
reports MP elevation of 519.33 ft for top of casing, based on leveling from
Waikapu 1 well MP elevation of 551.33 ft (6/21/83). DOWALD as-built drawing
provides elevation of 519.47 ft for top of 20-inch casing.
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DWS
Waikapu Mauka
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5131-01
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764.87
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--
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--
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USGS
surveying on 12/29/03 to top of 6-inch threaded coupling welded to plate
that is welded to the top of the 18-inch casing (highest point after
removing plug). CWRM well completion report and Water Resources
International as-built drawing provides elevation of 764.7 ft for top plate
welded to 18-inch casing.
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1 Revised well measuring-point
elevations were determined by the USGS using vertical leveling from
National Geodetic Survey benchmarks and reference marks in December 2003.
NGS benchmark and reference mark elevations provided by NGS on 1/20/04.
Leveling notes and photographs of the measuring points are available in
well folders maintained by the USGS Hawaii District Office.
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2 Difference calculated by
subtracting the previous from the revised well measuring-point elevation.
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3 All information contained in
USGS well folder.
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4 Maui Department of Water Supply
refers to this well as Mokuhau Pump 2 (Well 502)
whereas Commission on Water Resource Management well index refers to this
well as Mokuhau 1.
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Well measuring-point elevations,
in feet above mean sea level, for selected wells in central Maui.
Released
June 15 2006.
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Well
name
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State well number
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Measuring point elevation
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Kihei Shaft Pump 1
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4727-01
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4.58
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Kihei Exploratory
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4824-01
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594.30
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Kihei Shaft Pump 3
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4825-01
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4.83
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Maalaea Power Plant (Pump 1)
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4829-02
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16.93
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Maalaea 272
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4831-01
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165.50
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Puunene Airport Shaft
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4928-02
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50.08
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Waikapu
Shaft Pump 7
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5128-02
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5.37
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Waikapu
Baseyard
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5129-02
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227.36
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Puunene Pump 9
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5224-02
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5.48
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Puunene Pump 5
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5226-01
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4.62
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Puunene Pump 6
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5226-02
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5.08
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Puunene Pump 19
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5227-05
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74.50
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Reynolds
2
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5228-07
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116.90
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Maui Lani 2
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5229-03
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151.29
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Kaheka Pump 18
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5321-01
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4.78
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Central
Power Plant
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5327-07
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3.86
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Cannery
Shaft
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5328-01
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4.28
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Maui
Central Park 1
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5329-19
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74.99
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Maui
Central Park 3
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5329-21
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51.28
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Paia Pump 17
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5422-02
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5.05
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Lower
Paia Pump 16
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5423-02
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4.52
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Sprecklesville Pump 4
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5424-01
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4.40
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Last Modified: 03.18.2005 15:10DSO
URL: http://hi.water.usgs.gov/projects/project_cmaui_mp.html
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