A06_Construction_Drawings_PORE_Water_Well_FY23.pdf

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LEGEND

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PZ?72ZZ2a STATE PARK BOUNDARY

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POINT REYES NATIONAL SEASHORE

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SUB

SHEET

TITLE OF SHEET

C1

C2

C3

C4

COVER SHEET

GALLAGHER WELLS SITE LOCATION

GALLAGHER WELL #1 EXISTING DETAIL

GALLAGHER WELL #4 DETAIL

GALLAGHER WELL #4 WELL SPECIFICATIONS AND SEQUENCE OF EVENTS

SCALE OF MILES

0 1 2 3

I I I I I I I 1 2 3

SCALE OF KILOMETERS

WELL

TITLE OF DRAWING DRAWING NO.

GALLAGHER WELL /14

UNITED STATES LOCATION WITHIN PARK

DEPARTMENT OF THE INTERIOR GALLAGHER WELLS PKG. SHEET

NO.

NAME OF PARK

166 [IJ NATIONAL PARK SERVICE POINT REYES NATIONAL SEASHORE

033 DENVER SERVICE CENTER REGION COUNTY STATE

5 PACIFIC WEST MARIN CALIFORNIA 1 OF

EXISTING GALLAGHER WELL #1

EXISTING GALLAGHER WELL #1 WELL HEAD

24" DIA. STEEL CASING

6" CASING

APPROXIMATE DEPTH OF

SAND PACK WITHIN THE

EXISTING 6" DIA. WELL

EXISTING CONCRETE

SLAB�

@ EXISTING WELL SECTION

C2

4 0 4 8 e- - -

VERTICAL SCALE OF FEET

-2' o'

5'

10'

15'

20'

25'

30'

35'

40'

45'

50'

DESIGNED:

L. Cantrell @mID

L. Cantrell

TECH. REVIEW:

L. Cantrell

DATE:

EXISTING CONCRETE PAD;

FIELD VERIFY SIZE

OF EXISTING PAD

EXISTING GALLAGHER WELL #1

CONCRETE WELL PAD PLAN AND SECTION

2 0 2 4 e- - -

HORIZONTAL AND VERTICAL SCALE OF FEET

SUB SHEET NO. TITLE OF SHEET DRAWING NO.

#1

C2

GALLAGHER WELL PMIS/PKG NO.

EXISTING DETAIL

166033

SHEET

POINT REYES NATIONAL SEASHORE (PORE)

,,.,L_ _____________________________________________________________________________ L_..;;;..,_.::..:,_.;.::___,_ ____ ...J.... _______________ ---J.,;==---==

10/2022 3 OF 5

DESTROY EXISTING GALLAGHER

WELL #1 ACCORDING TO MARIN

COUNTY REGULATIONS

NEW CONCRETE

SLAB

W '09

NEW

SEAL

NEW 6" CASING

NEW SCREEN

f ii1

CONSTRUCT NEW SUPPLY WELL

(GALLAGHER WELL #4);

SEE SHEET C5

@ WELL SECTION

C3

4 0 4 8 e- - -

VERTICAL SCALE OF FEET

-2' o·

5'

10'

15'

20'

25'

30'

35'

40'

45'

50'

,, ly

,a

¢2'-4"

FIELD

VERIFY

GALLAGHER WELL #1 (TO

BE DESTROYED)

2'-0"

MIN

GALLAGHER WELL #4

(REPLACEMENT TO WELL #1)

CONCRETE WELL PAD PLAN AND SECTION

2 0 2 4 e- - -

HORIZONTAL AND VERTICAL SCALE OF FEET

DESIGNED: SUB SHEET NO. DRAWING NO.

L. CANTRELL ???

@mID ????

L. CANTRELL

C3

PMIS/PKG NO.

TECH. REVIEW: 166033

L. CANTRELL SHEET

DATE:

TITLE OF SHEET

GALLAGHER WELL DETAIL

POINT REYES NATIONAL SEASHORE (PORE)

10/2022

Figure 2. GW#4

Depth (feet)

5'

10'

15'

20'

25'

30'

35'

40'

45'

50'

12" hole

Gallagher Well #4 (replacement to well

#1)

Land Surface

Install 6-inch sanitary seal

Install bentonite chip seal (0 to 20 ft)

Install 1 ¼" PVC sounding tube

Install submersible pump on 21 ft of

I½" diameter PVC drop pipe

Install Monterey Sand Pack (20 to 48 ft)

Drill 12" diameter hole to 50 feet

Install 6" diameter slotted PVC casing (28 to 48 ft) two centralizers toward bottom of slotted casing cap on bottom of slotted casing hang casing 2 ft off bottom

Well Specifications, Sequence of Events, and Comments Figure 2 Gallagher Water Supply Well #4

I. Obtain domestic water supply well drilling permit from Marin County Health Department.

2. A new well, well #4, will be drilled and constructed as a replacement to well #1. The well location will be on the same 10 ft by 10 ft cement pad as the existing well. The location should be far enough from the existing well and at least two feet from edge of the cement pad.

3. The first step to the well construction process is to set and install the surface seal. At least 20 feet of 12-inch diameter steel casing is required. Prior to any drilling, a hole must be cored in the concrete slab. The hole should be large enough to accommodate the drilling of the 18" hole (approximately 2 ft in diameter).

4. Rig up to conduct mud rotary drilling. Use the appropriate bits and equipment to drill an 18-inch hole to a depth of 20 feet.

5. Install the 12-inch diameter steel casing (0.375 wall thickness). Spud the casing and maintain a plumbness required for cementing. Mix up neat cement and install using a l ½" tremie pipe located in the annular space. Refer to the California Water Well Standards (Bulletin 77-1 ) for details and specifications for installing seals in water wells. Allow the seal to set up overnight prior to any further drilling.

6. Drill 12-inch diameter hole to a depth of 50 feet. Log in drill cuttings every five feet to determine the appropriate sand depths. The lithology should be similar to that from the original well #1. At a depth of 50 feet, maintain circulation until the hole is clean of any cuttings. Prepare to install 6-incb PVC casing.

7. Install 50 feet of6-inch Schedule 80 (or comparable) PVC casing. The casing can be flush-joint or coupled with slip couplings or belled couplings. The standard lengths shall be l O or 20 foot sections. Hang the casing 2 feet off bottom resulting in a casing height of2 feet above land surface.

8. The bottom joint (28 to 48 feet) will be slotted casing (0.020 slot). Prior to installation, thread bottom plug into bottom of the screen section. The remaining part of the well will be constructed with six-inch blank PVC casing (-2 feet to 28 feet).

9. Attach two small centralizers to the slotted section approximately two feet from the bottom. The centralizers shall be sized for the 6-inch PVC (6.5" OD diameter) in the twelve-inch hole (12" ID diameter). The installed sand pack shall to be placed below the centralizers.

10. With the casing string suspended 2 feet of bottom, prepare to install the sand pack (Monterey Sand 8-16).

The depth of the sand pack shall be at 20 feet below land surface. The remaining annular space (0 to 20 feet) will be sealed with bentonite chips.

11. Seal the remaining annular space with ¼" or 3/," bentonite chips.

12. Develop the well with air. Run the casing string up and down through the slotted interval to clean the well of mud. Continue co develop the well until the water is clean and sand free.

13. When the well is clean, conduct some brief airlift tests to determine the well yield and water quality characteristics of the well.

14. Secure well with vented well cap.

15. Remove test pump and equipment.

16. Install permanent pump and motor based on information collected from the pumping tests. The pump shall be submersible, stainless steel capable of pumping 50 GPM with a TDH of 370 feet. The motor shall be a 230 volt, 3 phase, 60 Hz (3450 rpm) model. The pump shall be equipped with a check valve at the top and sized with a 2-inch fitting for attachment to the 2-inch PVC drop pipe. Install 1 ¼" PVC sounding tube that can be used for collecting water level measurements and a permanent pressure transducer. Set the top of the pump at approximately a depth of 21-feet.

17. Prepare for pump tests on well. Conduct a 6-hour three step-drawdown test and an 8-hour constant rate pump test on the new well. Collect water level measurements. Other wells may be used as a monitoring well.

Collect final water sample. Check to top of storage tanks prior to test.

18. Secure well with sanitary well seal.

19. Perform any tests and water sampling required for permitting the well as a source of potable water for a domestic water system.

20. Reclaim site and repair damage to the concrete pad and construct new portion of pad.

DESIGNED: SUB SHEEf NO. TITLE OF SHEEf

L. CANTRELL FIG. 2 GALLAGHER

@r.1ill)

WELL #4

L. CANTRELL

C4 WELL SPECIFICATIONS

TECH. REVIEW: AND SEQUENCE OF EVENTS L. CANTRELL

DATE: POINT REYES NATIONAL SEASHORE (PORE)

DRAWING NO.

PMIS/PKG NO.

166033

SHEEf

5 OF5

,,.,,..._ ____________________________________________________________________________________ __._....._ 10/2022

Drill 18" diameter hole to 20 feet

Install 12" diameter steel casing

Cement 12" casing in 18" hole