Your SlideShare is downloading. ×

Deq wb-dwehs-wcu-waterwellconst 221591-7(1)

216

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
216
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
9
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. WELL CONSTRUCTION PROGRAMENVIRONMENTAL HEALTH PROGRAMS UNITDRINKING WATER & ENVIRONMENTAL HEALTH SECTIONRESOURCE MANAGEMENT DIVISION
  • 2. Statute: Part 127 – Water Supply and Sewer SystemsAct 368, PA 1978, as amended (Public Health Code) (MCLA 333.12701 – 12715) R 325.1601 – 325.1781 • Part 1 – Well Construction Code • Part 2 - Drilling Contractors’ & Pump Installers’ Registration • Part 3 – Drilling Machines & Service Vehicles • Part 4 - Dewatering Wells FIRST BECAME EFFECTIVE FEB. 14, 1967 LAST REVISION – EFFECTIVE APRIL 21, 1994 For public water supply wells - Apply Part 8, Act 399, PA 1976 in addition to Part 127, Public Health Code
  • 3. U. S. Commerce, Bureau of Census1990 Detailed Housing Characteristics 1.12 million household wells in Michigan HIGHEST IN
  • 4. PROPER SANITARY WELL TRAINED WELL CONSTRUCTION PROFESSIONAL COMPLETION MATERIALS WATER WELL PRACTICES CONTRACTORS COMPONENTS OF A SAFE & RELIABLE WATER WELL TARGET PROPERAQUIFER HAS WATERAMPLE YIELD SUFFICIENT ROUTINE SYSTEM & SEPARATION MONITORING MAINTENANCESAFE WATER FROM OF CONTAMINATION WATER SOURCES QUALITY
  • 5. DEFICIENT WELL HEAD OLD WELLS WITH (CRACKED WELL CAP CORRODED OR OPEN VENT) WELL CASINGPOOR CONSTRUCTION SHALLOW DEPTH(UNSEALED ANNULUS (OR SHORT CASING OR DUG WELL) IN BEDROCK) WELLS MOST VUNERABLE TO MICROBIAL CONTAMINATION FLOODING, SEWER LINE BREAK, BURIED WELL HEAD TOO CLOSE TO SEWAGE OVERFLOW OR SUBMERGED SEPTIC SYSTEM, OR CROSS- IN WELL PIT AGRIC. RUNOFF OR CONNECTION ABANDONED WELL
  • 6. What is the total annual footage of water wells drilled in Michigan ? Answer : Year Million Feet 2005 ………………………. 3.2 2006 ………………………. 2.7
  • 7. WATER WELL USE PUBLIC SUPPLY AGR. IRRIGATIONOTHER 2% INDUSTRIAL TEST WELL OTHER HOUSEHOLD 98%
  • 8. RADIUS OF STATIC WATER LEVEL INFLUENCEWATER TABLE DRAWDOWN CONE OFDEPRESSION PUMPING AQUIFER WATER LEVEL
  • 9. DRILLEDDRIVEN DUG
  • 10.  Provide well that meets needs of owner Obtain highest yield with minimal drawdown(consistent w/ aquifer capabilities) Provide suitable quality water (potable andturbidity-free for drinking water wells) Provide long service life (25+ years)NEW: Minimize impacts on neighboring wells &aquatic environments
  • 11. DRILLED WELLS Terminated in glacial drift (sand,gravel) or bedrock Constructed with rotary, cabletool, jetting, hollow rod or augerdrilling methods 2 in. or larger casing(Domestic wells: 4 – 6 inch diameter)
  • 12. DRILLED WELLS Casing material: Steel or PVC plastic Installed by well drilling contractors Much more common than driven ordug wells Most are >50 ft. deep (avg. 125 ft.) MOST SANITARY WELL TYPE
  • 13. WATER WELL DRILLING METHODS IN MICHIGAN MOST COMMON: LESS COMMON: CABLE TOOL AUGER 10% 2.5% ROTARY (Mud & Air) JETTING 1% 84% HOLLOW ROD OTHER 0.5% 2% EMERGING TECHNOLOGYDUAL TUBE ROTARY HORIZONTAL SONIC
  • 14. Rotary Cable Tool
  • 15. TABLE MUD MAST DRIVE HOSEROTARY SWIVEL TABLE DRILL RODS MUD MIXER BENTONITE DRILL DRILLING MUD PIT BIT FLUID
  • 16. TOP HEAD DRIVE ROTARYTOP HEAD DERRICKDRIVE UNIT OR MASTDRILLING MUDRETURN FLOWHOSE DRILL RODS
  • 17. DRILLING RIG OPERATORCHECKING DRILL CUTTINGS DRILLING FLUID STRAINER EXITING BOREHOLE DRILLING MUD TANK
  • 18. DRILLER COMPLETING THE WATER WELL RECORD WATER WELL & PUMP RECORD DESCRIBES: WELL DEPTH CASING LENGTH GEOLOGIC MATERIALS PENETRATED STATIC WATER LEVEL PUMPING WATER LEVEL PUMPING RATE GROUTING MATERIALS WELL LOCATION PUMPING EQUIPMENT DRILLERS NAME DRILLING RIG OPERATOR
  • 19. TYPICAL ROTARY WELL CONSTRUCTION SEQUENCE1 2 3 OVERSIZED IDENTIFY INSTALL CASING BOREHOLE AQUIFER (& SCREEN) DRILLED6 5 4 YIELD TEST GROUT WELL & ANNULAR DEVELOPMENTWATER SAMPLING SPACE
  • 20. Bentonite Drilling Fluid - Functions -• REMOVAL OF DRILL CUTTINGS FROM BOREHOLE• STABILIZE THE BOREHOLE• COOL AND LUBRICATE DRILL BIT• CONTROL FLUID LOSS TO GEOLOGIC FORMATIONS• DROP DRILL CUTTINGS INTO MUD PIT• FACILITATE COLLECTION OF GEOLOGIC DATA• SUSPEND CUTTINGS WHEN DRILLING FLUID CIRCULATION STOPS
  • 21. Temporary well cap -installed betweenwell drilling andpump hook-up
  • 22. Sanitary well cap(overlapping &self-draining) Screened air vent on underside of well capTight sealbetween capand casing Electrical conduit Well casing pipe
  • 23. This drilled wellhas an older stylewell cap that doesnot seal tightly tothe well casing.Insects and smallanimals can enterthe well andcontaminate thedrinking water.Caps of thisdesign are notacceptable andshould bereplaced.
  • 24. DRILLED WELL COMPONENTSWELL CAP or SEAL BOREHOLE SCREENED CASING WELL GROUT PACKER SCREEN
  • 25. DRILLED WELL COMPONENTS WELL CAP BEDROCK BOREHOLE WELL CASING GROUT OPEN HOLE IN NO CASING BEDROCK IN ROCK BOREHOLE AQUIFER
  • 26. BOREHOLE MINIMUM 2 IN. LARGER THANVertical circular CASING IF GROUTING boring to reach THRU CASING aquifer (waterbearing geologic MINIMUM 2 7/8 IN. LARGER THAN material) CASING IF GROUTING WITH GROUT PIPE OUTSIDE CASING
  • 27. CASING Steel or plastic pipe installed to keep borehole wall from collapsing STANDARD LENGTHS STEEL 21 FT. Housessubmersible pump PLASTIC 20 FT.or turbine bowls & MINIMUM 25 FT. CASING drop pipe LENGTH BELOW GRADE
  • 28. WELL CAP or SEAL OVERLAPPINGMechanical device to prevent SEALED TIGHTLY TO CASING contaminants(including insects) SCREENED AIR VENTfrom entering well casing TIGHT SEAL TO ELECTRICAL CONDUIT
  • 29. Device that seals space between casing & telescoped screen to keep sand out of well PACKER(Coupling withneoprene rubber flanges)
  • 30. Intake device toallow water to enterwell and keep sand outStructural support of aquifer material SCREENWire-wrapped screen most common
  • 31. K - PACKER SCREEN BLANKWELL SCREEN
  • 32. Impermeable cement or GROUT bentonite clay slurryplaced in annular space between borehole and casing to: TOP VIEW prevent well contamination maintain separation of aquifers preserve artesian aquifers CASING BOREHOLE
  • 33. DOWNWARD LEAKAGE AROUND UNGROUTED CASING INFILTRATION FROM SURFACE CONTAMINANTS STATIC WATER LEVELCONTAMINANT PLUME UNSEALED ANNULAR SPACE AROUND CASING DOWNWARD LEAKAGE UNCONFINED AQUIFER
  • 34. UPWARD LEAKAGE AROUND UNGROUTED CASING (Artesian Condition) STATIC WATER LEVELUNCONFINEDAQUIFER CONFINING LAYERCONFINED UPWARD LEAKAGEAQUIFER
  • 35. BENEFITS OF WELL GROUTING• PREVENT CONTAMINANT MIGRATION FROM SURFACE (Keeps surface runoff from moving downward along well casing)• SEAL OFF POOR QUALITY AQUIFERS (Prevents mixing of water from different aquifers)• PRESERVE ARTESIAN AQUIFER PROPERTIES• ADDED SEALING OF CASING JOINTS
  • 36. WELL GROUTING MATERIALS TYPE COMPOSITION CHARACTERISTICS POWDERED BENTONITE FLEXIBLE LOWER STRENGTH SEAL & WATER MAY SUBSIDE IN VADOSE ZONE BENTONITE MOST POPULAR DUE TO LOWER COST SLURRY GRANULAR BENTONITE, AND TARGETED MARKETING POLYMER & WATER WASH-OUT UNDER ARTESIAN PRESSURE NO HEAT OF HYDRATION MORE WIDELY USED IN OIL FIELD THAN PORTLAND CEMENT & WATER WATER WELLS HIGHER STRENGTH RIGID SEALNEAT CEMENT BEST CHOICE FOR BEDROCK WELLS & FLOWING WELLS HEAT OF HYDRATION & MICROANNULUS CONCERNS PORTLAND CEMENT, SAND MORE PERMEABLE THAN NEAT CONCRETE & WATER CEMENT GROUT MORE DIFFICULT TO PUMP (ABRASIVE) GROUT GOOD CHOICE FOR LARGE DIAMETER WELLS
  • 37. GRANULAR BENTONITE POURED INTO MIX WATER PORTABLE GROUTING MACHINE (MIXER & PUMP) GROUT PIPE TO BOTTOM OF ANNULAR SPACE BENTONITE GROUT RETURN AT SURFACE(GELATIN – OATMEAL TEXTURE)
  • 38. WELL GROUTING ROTARY VS. CABLE TOOLGROUT PIPE IN DRY GRANULAR BENTONITEANNULAR SPACE POURED AROUND CASING WELL CASING GROUT FOLLOWS DRIVE SHOE IN OVERSIZED AS CASING IS DRIVEN BOREHOLE • DEPTH OF GROUT TRAVEL IS UNCERTAINGROUT PUMPED FROM BOTTOM • LIMITED BY HIGH WATER TABLE
  • 39. BEDROCK WELL DETAILS CASING PIPE SHALE TRAP OR GROUT SHALE PACKER PREVENTS GROUTTOP OF BEDROCK SPILLAGE INTO BEDROCK BOREHOLEBEDROCK BOREHOLE BETTER SEAL AT(SMALLER DIAMETER BEDROCK INTERFACETHAN CASING)
  • 40. Groundwater Concerns in Karst Bedrock UNPLUGGED AGRICULTURAL SEWAGE ABANDONED WASTE & RUNOFF SYSTEM WELL SINKHOLE CONTAMINATED WATER SEEPS DOWNWARD THROUGH THIN SOIL LAYER INTO FRACTURES & CREVICES IN KARST BEDROCKSIGNIFICANT RAINFALL OVER SHALLOW CARBONATE BEDROCKCAN CAUSE:• SURGE IN WATER LEVELS (Increases hydraulic pressure)• INCREASED SURFACE WATER-TO-GROUNDWATER INTERCHANGE• FLUSHING OF TURBIDITY & ORGANIC MATTER INTO GROUNDWATER
  • 41. PROPER WELL CONSTRUCTION IN KARST SURFACEGLACIAL DRIFT CASING & GROUT EXTENDING OVER THRU UPPER BEDROCK BEDROCK IF BEDROCK WITHIN 25 FT OF SURFACE: MINIMUM 25 FT OF CASING GROUTED WITH NEAT CEMENT – BENTONITE GROUT NOT PERMITTEDTOP OF BEDROCK SEVERELY WEATHERED LIMESTONE BEDROCK FRACTURES & INTERCONNECTED SOLUTION CHANNELS SHALE UNCASED BOREHOLE LIMESTONE IN BEDROCK
  • 42. POOR WELL CONSTRUCTION IN KARST SURFACEGLACIAL DRIFT OVER BEDROCK CASING & GROUT ONLY EXTEND INTO TOP OF BEDROCK EVEN THROUGH CASING & GROUTING EXTENDS 25 FT. SAFE WATER QUALITY CANNOT BE ASSURREDTOP OF BEDROCK SEVERELY WEATHERED LIMESTONE BEDROCK FRACTURES & INTERCONNECTED SOLUTION CHANNELS BECAUSE BOREHOLE BELOW CASING INTERCEPTS SHALE SHALLOW, FRACTURED BEDROCK… WELL IS VULNERABLE TO CONTAMINATION FROM SEPTIC SYSTEMS, LUSTs, AGRICULTURAL CHEMICALS & SURFACE WATER INFILTRATION UNCASED BOREHOLE SYMPTOMS – E.COLI OR SURFACE WATER INDICATORS PRESENT LIMESTONE AND SUSCEPTIBLE TO TURBIDITY AFTER HEAVY RAINFALL IN BEDROCK
  • 43. WELL CASING DEPTH IN KARST GLACIAL DRIFT OVER BEDROCK SEVERELY WEATHERED LIMESTONE BEDROCK FRACTURES & INTERCONNECTED SOLUTION CHANNELS BENEFITS OF EXTENDING WELL CASING THROUGH UPPER FRACTURED BEDROCK: 1. TRAVEL TIME OF AQUIFER RECHARGE WATER IS INCREASED UNCASED BOREHOLELIMESTONE 2. DIE-OFF OF PATHOGENS MORE LIKELY TO OCCUR IN BEDROCK 3. IMPROVES CHANCES OF COLIFORM-FREE WATER
  • 44. PVC PLASTIC VS. STEELNon-corroding CorrodesLower strength Higher strengthFewer water quality Rusty watercomplaintsRotary construction only Suitable for any drilling method1/3 cost of steel No heat of hydration impact from cement groutSDR 17 needed past 200 ft.
  • 45. TYPICAL 5 IN. DIAMETERHOUSEHOLD WELLCONTRACTOR ISCUTTING PVC CASINGTO FINISHED HEIGHT(MIN. 12 IN. ABOVEGROUND)
  • 46. WELL DIAMETER: Doubling well diameter MYTH appreciably increases well yield DOUBLING WELL DIAMETER 10% YIELD INCREASE FACT DOUBLING SCREEN LENGTH DOUBLES WELL YIELD
  • 47. Naturally FilterDeveloped Packed (a/k/a Gravel-Packed) WELL SCREEN SET IN GRADED-WASHED NATIVE GEOLOGIC SAND PLACED MATERIALS OUTSIDE(SAND OR GRAVEL) WELL SCREEN
  • 48. BENEFITS Greater porosity Faster development Higher hydraulic Easier groutingconductivity Longer well life Reduced drawdown Improved well Higher yield rehabilitation Reduced entrance Reduce sandvelocity pumping
  • 49. FILTER-PACKED WELL CONSTRUCTION CASINGFILTER-PACK GROUTSAND PLACEDBETWEEN CASINGBOREHOLE & CENTERINGSCREEN BEFORE GUIDESGROUTING (OPTIONAL)FILTER PACK IS NOTALLOWED TO EXTENDMORE THAN 10 FEET SCREENABOVE TOP OF SCREEN
  • 50. DISINFECTED FILTERSAND POURED INTOANNULUS AFTERCASING & SCREENARE INSTALLED ANDDRILLING MUD ISFLUSHED FROMBOREHOLE
  • 51. WELL SCREEN SELECTION CRITERIA• Maximize % open area BEST WORST CONTINUOUS SLOT SAW – CUT WIRE WOUND OR GAUZE-COVERED• Non-clogging openings• Corrosion resistance STAINLESS STEEL vs. PVC PLASTIC• Column & collapse strength
  • 52. SCREEN SELECTION CRITERIAScreen opening size based on aquifer materialsize: SIEVE ANALYSIS vs. S.W.A.G.NATURALLY-DEVELOPED WELL: 40% RETENTION OF AQUIFER MATERIALFILTER-PACKED WELL: 90% RETENTION OF FILTER SANDScreen diameter: BASED ON CASING SIZE MINERAL PROVIDE WATER ENTRANCE VELOCITY INCRUSTATIONOF… <0.1 FT./SEC. Lower velocity reduces mineral incrustation EXTENDS WELL SERVICE LIFE
  • 53. ENTRANCE VELOCITY = PUMPING RATE SCREEN OPEN AREA Example: 6 in. Pipe Size X 8 ft. length 10 SLOT = 10/1000 IN. OPENING 10 slot Continuous slot SS Pumping rate = 75 GPMScreen open area (from manufacturer) = 0.21 ft2/lin ftTotal screen area = 8 ft x 0.21 ft2/lin ft = 1.68 ft2CONVERT GPM TO FT3/SEC75 GPM x 1 ft3/7.48 gal x 1 min/60 sec = 0.167 ft3/sec0.167 ft3/sec / 1.68 ft2 = 0.099 ft/sec CROSS-SECTIONIs an entrance velocity of 0.099 ft/sec OF SCREEN WIREacceptable?
  • 54. IN KNOWN FLOWING WELL AREAS: CEMENTCASING INTO CONFINING LAYER BEFORE CONFINING LAYERPENETRATING ARTESIAN AQUIFER ARTESIAN INSTALL TELESCOPED AQUIFER CASING WITHIN OUTER CASING
  • 55. SURFACE HIGH-CAPACITY WELL 16 “ OUTER DESIGN CONCERNS CASING 12” INNER CASING NEAT CEMENT STRING GROUTINNER CASING IS “PERMANENT CASING”. 100 FT.WELL CODE REQUIRES GROUTINGFROM NOT MORE THAN 10 FT. ABOVE FILTER PACKSCREEN UP TO SURFACE – ZONE FROM SAND100 FT. TO 190 FT. IS UNGROUTED AND (extendingVIOLATES R 325.1634a OF WELL CODE. into outer casing)PROBLEMS FROM THIS DESIGN MAYINCLUDE:• COMMINGLING OF WATER FROM SEPARATE AQUIFERS WELL• STAGNANT WATER IN FILTER PACK SCREEN ABOVE SCREEN (10 ft. length) 200 FT.
  • 56. CLEAN WATER PUMPEDFROM WELL DURINGFINAL DEVELOPMENTSTAGE
  • 57. DRIVEN WELLS Installed in glacial drift only -CANNOT be driven thru boulders orinto bedrock Well point driven into groundwith post-driver, tripod w/ weight orsledge hammer 1 1/4 in. to 2 in. diameter
  • 58. DRIVEN WELLS Installed by property owners Common around lakes and highwater table areas Most <35 ft. deep, limited yield (7gpm or less) MORE SUSCEPTIBLE TO SURFACE CONTAMINATION THAN DRILLED WELLS
  • 59. TRIPOD WELLS BEING DRIVENCASINGDRIVER 1 ¼ IN. CASING
  • 60. DUG WELLS Large diameter (18-48 in.) Found in low yield areas (Thumb& SE Michigan) Casing material - concrete crocksw/ loose joints Older wells: stones, brick-lined Water enters well through loosecasing joints
  • 61. SHALLOW UNSANITARY DUG CROCK WELL
  • 62. OLD UNSANITARY HAND-DUG WELL LINED WITH FIELD STONE
  • 63. DUG WELLS Older wells - hand dug Now installed (on very limited basis) w/bucket augers (backhoes – phased out) Low well yield - storage in casing(100’s of gallons) HIGHLY VULNERABLE TOCONTAMINATION
  • 64. CDC Findings on Dug Wells• Dug/bored wells had a positive coliform bacteria rate of about 85%• Wells with brick, concrete or wood casing (dug wells) had coliform positive rates of 60 – 90 %From A Survey of the Presence of Contaminants in WaterFrom Private Wells in Nine Midwestern States, Atlanta, Georgia, U.S.Dept. of Health and Human Services, Public Health Service, Centersfor Disease Control, 1996
  • 65. DUG WELLS• Needs LHD approval under R 325.1674 of well code….before installation30 in. diameter fiberglass casing(NSF Std. 61 listed) accepted by MDEQ for bucket auger wells REPLACEMENT FOR CONCRETE CROCKS
  • 66. Water Quality in theNew WorldIn 1610, Jamestown’s Governor proclaimed:“There shall be no man or woman dare to wash any unclean linen, wash clothes, … nor rinse or make clean any kettle, pot or pan, or any suchlike vessel within 20 feet of the old well or new pump. Nor shall anyone foresaid within less than quarter mile of the fort, dare to do the necessities of nature, since by these unmanly, slothful, and loathsome immodesties, the whole fort may be choked and poisoned.”
  • 67. REMEMBER….. ALWAYS DRINK UPSTREAM OF THE HERD
  • 68. Contact DEQ Well Construction Program at 517-241-1377

×