WELL CONSTRUCTION PROGRAMENVIRONMENTAL HEALTH PROGRAMS UNITDRINKING WATER & ENVIRONMENTAL HEALTH SECTIONRESOURCE MANAGEMEN...
Statute: Part 127 – Water Supply and Sewer SystemsAct 368, PA 1978, as amended (Public Health Code)              (MCLA 333...
U. S. Commerce, Bureau of Census1990 Detailed Housing Characteristics                1.12 million             household we...
PROPER  SANITARY              WELL                 TRAINED    WELL            CONSTRUCTION           PROFESSIONAL COMPLETI...
DEFICIENT WELL HEAD    OLD WELLS WITH            (CRACKED WELL CAP        CORRODED              OR OPEN VENT)         WELL...
What is the total annual footage of water wells drilled in Michigan ?  Answer :  Year             Million Feet  2005 ……………...
WATER WELL USE             PUBLIC SUPPLY             AGR. IRRIGATIONOTHER 2%     INDUSTRIAL             TEST WELL         ...
RADIUS OF   STATIC WATER LEVEL     INFLUENCEWATER TABLE            DRAWDOWN CONE OFDEPRESSION                 PUMPING   AQ...
DRILLEDDRIVEN  DUG
 Provide well that meets needs of owner Obtain highest yield with minimal drawdown(consistent w/ aquifer capabilities) ...
DRILLED WELLS   Terminated in glacial drift (sand,gravel) or bedrock    Constructed with rotary, cabletool, jetting, hollo...
DRILLED WELLS  Casing material: Steel or PVC plastic  Installed by well drilling contractors  Much more common than driven...
WATER WELL DRILLING METHODS                   IN MICHIGAN  MOST COMMON:                   LESS COMMON:                    ...
Rotary   Cable Tool
TABLE       MUD                           MAST DRIVE       HOSEROTARY                                SWIVEL               ...
TOP HEAD DRIVE ROTARYTOP HEAD                             DERRICKDRIVE UNIT                           OR MASTDRILLING MUDR...
DRILLING RIG OPERATORCHECKING DRILL CUTTINGS                                 DRILLING                                 FLUI...
DRILLER COMPLETING THE  WATER WELL RECORD                WATER WELL & PUMP                RECORD DESCRIBES:               ...
TYPICAL         ROTARY WELL CONSTRUCTION                 SEQUENCE1                2                 3    OVERSIZED        ...
Bentonite Drilling Fluid              - Functions -• REMOVAL OF DRILL CUTTINGS FROM BOREHOLE• STABILIZE THE BOREHOLE• COOL...
Temporary well cap -installed betweenwell drilling andpump hook-up
Sanitary well cap(overlapping &self-draining)      Screened air                    vent on underside                    of...
This drilled wellhas an older stylewell cap that doesnot seal tightly tothe well casing.Insects and smallanimals can enter...
DRILLED WELL COMPONENTSWELL CAP or   SEAL BOREHOLE       SCREENED CASING           WELL GROUT PACKER SCREEN
DRILLED WELL COMPONENTS WELL CAP                 BEDROCK BOREHOLE                  WELL CASING GROUT OPEN HOLE IN     NO C...
BOREHOLE                    MINIMUM 2 IN.                    LARGER THANVertical circular   CASING IF                    G...
CASING Steel or plastic pipe installed to  keep borehole    wall from    collapsing                       STANDARD        ...
WELL CAP or   SEAL                       OVERLAPPINGMechanical device     to prevent       SEALED TIGHTLY                 ...
Device that seals   space between      casing & telescoped screen  to keep sand out       of well   PACKER(Coupling withne...
Intake device toallow water to enterwell and keep sand        outStructural support of   aquifer material                 ...
K - PACKER SCREEN BLANKWELL SCREEN
Impermeable cement or                          GROUT  bentonite clay slurryplaced in annular space between borehole and   ...
DOWNWARD LEAKAGE AROUND    UNGROUTED CASING                    INFILTRATION FROM                    SURFACE CONTAMINANTS  ...
UPWARD LEAKAGE AROUND     UNGROUTED CASING           (Artesian Condition)                            STATIC WATER LEVELUNC...
BENEFITS OF WELL GROUTING• PREVENT CONTAMINANT MIGRATION  FROM SURFACE (Keeps surface runoff  from moving downward along w...
WELL GROUTING MATERIALS    TYPE        COMPOSITION                  CHARACTERISTICS               POWDERED BENTONITE      ...
GRANULAR BENTONITE                                 POURED INTO                                  MIX WATER                 ...
WELL GROUTING         ROTARY             VS.            CABLE TOOLGROUT PIPE IN                     DRY GRANULAR BENTONITE...
BEDROCK  WELL DETAILS          CASING PIPE                          SHALE TRAP                                OR          ...
Groundwater Concerns in Karst Bedrock                                                                   UNPLUGGED     AGRI...
PROPER WELL CONSTRUCTION IN KARST   SURFACEGLACIAL DRIFT              CASING & GROUT EXTENDING    OVER                    ...
POOR WELL CONSTRUCTION IN KARST   SURFACEGLACIAL DRIFT    OVER  BEDROCK                 CASING & GROUT ONLY EXTEND INTO   ...
WELL CASING DEPTH IN KARST            GLACIAL DRIFT                OVER              BEDROCK          SEVERELY WEATHERED  ...
PVC PLASTIC             VS.           STEELNon-corroding                    CorrodesLower strength                   Highe...
TYPICAL 5 IN. DIAMETERHOUSEHOLD WELLCONTRACTOR ISCUTTING PVC CASINGTO FINISHED HEIGHT(MIN. 12 IN. ABOVEGROUND)
WELL DIAMETER:             Doubling well diameter   MYTH      appreciably increases                   well yield          ...
Naturally             FilterDeveloped             Packed                   (a/k/a Gravel-Packed)  WELL SCREEN      SET IN ...
BENEFITS  Greater porosity     Faster development  Higher hydraulic      Easier groutingconductivity                      ...
FILTER-PACKED WELL CONSTRUCTION                      CASINGFILTER-PACK                     GROUTSAND PLACEDBETWEEN        ...
DISINFECTED FILTERSAND POURED INTOANNULUS AFTERCASING & SCREENARE INSTALLED ANDDRILLING MUD ISFLUSHED FROMBOREHOLE
WELL SCREEN SELECTION CRITERIA• Maximize % open area       BEST             WORST  CONTINUOUS SLOT        SAW – CUT    WIR...
SCREEN SELECTION CRITERIAScreen opening size based on aquifer materialsize:       SIEVE ANALYSIS vs. S.W.A.G.NATURALLY-DEV...
ENTRANCE VELOCITY = PUMPING RATE                   SCREEN OPEN AREA  Example:    6 in. Pipe Size X 8 ft. length           ...
IN KNOWN FLOWING WELL AREAS:   CEMENTCASING INTO CONFINING    LAYER   BEFORE              CONFINING LAYERPENETRATING  ARTE...
SURFACE  HIGH-CAPACITY WELL                                    16 “ OUTER   DESIGN CONCERNS                               ...
CLEAN WATER PUMPEDFROM WELL DURINGFINAL DEVELOPMENTSTAGE
DRIVEN WELLS   Installed in glacial drift only -CANNOT be driven thru boulders orinto bedrock   Well point driven into gro...
DRIVEN WELLS  Installed by property owners  Common around lakes and highwater table areas  Most <35 ft. deep, limited yiel...
TRIPOD             WELLS BEING               DRIVENCASINGDRIVER   1 ¼ IN.   CASING
DUG WELLS  Large diameter (18-48 in.)   Found in low yield areas (Thumb& SE Michigan)   Casing material - concrete crocksw...
SHALLOW UNSANITARY DUG CROCK WELL
OLD UNSANITARY HAND-DUG WELL    LINED WITH FIELD STONE
DUG WELLS   Older wells - hand dug   Now installed (on very limited basis) w/bucket augers (backhoes – phased out)   Low w...
CDC Findings on Dug Wells• Dug/bored wells had a positive  coliform bacteria rate of about 85%• Wells with brick, concrete...
DUG WELLS• Needs LHD approval  under R 325.1674 of well  code….before installation30 in. diameter fiberglass casing(NSF St...
Water Quality in theNew WorldIn 1610, Jamestown’s Governor proclaimed:“There shall be no man or woman dare to wash any unc...
REMEMBER….. ALWAYS DRINK UPSTREAM OF THE HERD
Contact DEQ Well Construction Program           at 517-241-1377
Deq wb-dwehs-wcu-waterwellconst 221591-7(1)
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Deq wb-dwehs-wcu-waterwellconst 221591-7(1)

  1. 1. WELL CONSTRUCTION PROGRAMENVIRONMENTAL HEALTH PROGRAMS UNITDRINKING WATER & ENVIRONMENTAL HEALTH SECTIONRESOURCE MANAGEMENT DIVISION
  2. 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. 3. U. S. Commerce, Bureau of Census1990 Detailed Housing Characteristics 1.12 million household wells in Michigan HIGHEST IN
  4. 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. 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. 6. What is the total annual footage of water wells drilled in Michigan ? Answer : Year Million Feet 2005 ………………………. 3.2 2006 ………………………. 2.7
  7. 7. WATER WELL USE PUBLIC SUPPLY AGR. IRRIGATIONOTHER 2% INDUSTRIAL TEST WELL OTHER HOUSEHOLD 98%
  8. 8. RADIUS OF STATIC WATER LEVEL INFLUENCEWATER TABLE DRAWDOWN CONE OFDEPRESSION PUMPING AQUIFER WATER LEVEL
  9. 9. DRILLEDDRIVEN DUG
  10. 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. 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. 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. 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. 14. Rotary Cable Tool
  15. 15. TABLE MUD MAST DRIVE HOSEROTARY SWIVEL TABLE DRILL RODS MUD MIXER BENTONITE DRILL DRILLING MUD PIT BIT FLUID
  16. 16. TOP HEAD DRIVE ROTARYTOP HEAD DERRICKDRIVE UNIT OR MASTDRILLING MUDRETURN FLOWHOSE DRILL RODS
  17. 17. DRILLING RIG OPERATORCHECKING DRILL CUTTINGS DRILLING FLUID STRAINER EXITING BOREHOLE DRILLING MUD TANK
  18. 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. 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. 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. 21. Temporary well cap -installed betweenwell drilling andpump hook-up
  22. 22. Sanitary well cap(overlapping &self-draining) Screened air vent on underside of well capTight sealbetween capand casing Electrical conduit Well casing pipe
  23. 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. 24. DRILLED WELL COMPONENTSWELL CAP or SEAL BOREHOLE SCREENED CASING WELL GROUT PACKER SCREEN
  25. 25. DRILLED WELL COMPONENTS WELL CAP BEDROCK BOREHOLE WELL CASING GROUT OPEN HOLE IN NO CASING BEDROCK IN ROCK BOREHOLE AQUIFER
  26. 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. 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. 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. 29. Device that seals space between casing & telescoped screen to keep sand out of well PACKER(Coupling withneoprene rubber flanges)
  30. 30. Intake device toallow water to enterwell and keep sand outStructural support of aquifer material SCREENWire-wrapped screen most common
  31. 31. K - PACKER SCREEN BLANKWELL SCREEN
  32. 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. 33. DOWNWARD LEAKAGE AROUND UNGROUTED CASING INFILTRATION FROM SURFACE CONTAMINANTS STATIC WATER LEVELCONTAMINANT PLUME UNSEALED ANNULAR SPACE AROUND CASING DOWNWARD LEAKAGE UNCONFINED AQUIFER
  34. 34. UPWARD LEAKAGE AROUND UNGROUTED CASING (Artesian Condition) STATIC WATER LEVELUNCONFINEDAQUIFER CONFINING LAYERCONFINED UPWARD LEAKAGEAQUIFER
  35. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 45. TYPICAL 5 IN. DIAMETERHOUSEHOLD WELLCONTRACTOR ISCUTTING PVC CASINGTO FINISHED HEIGHT(MIN. 12 IN. ABOVEGROUND)
  46. 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. 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. 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. 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. 50. DISINFECTED FILTERSAND POURED INTOANNULUS AFTERCASING & SCREENARE INSTALLED ANDDRILLING MUD ISFLUSHED FROMBOREHOLE
  51. 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. 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. 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. 54. IN KNOWN FLOWING WELL AREAS: CEMENTCASING INTO CONFINING LAYER BEFORE CONFINING LAYERPENETRATING ARTESIAN AQUIFER ARTESIAN INSTALL TELESCOPED AQUIFER CASING WITHIN OUTER CASING
  55. 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. 56. CLEAN WATER PUMPEDFROM WELL DURINGFINAL DEVELOPMENTSTAGE
  57. 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. 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. 59. TRIPOD WELLS BEING DRIVENCASINGDRIVER 1 ¼ IN. CASING
  60. 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. 61. SHALLOW UNSANITARY DUG CROCK WELL
  62. 62. OLD UNSANITARY HAND-DUG WELL LINED WITH FIELD STONE
  63. 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. 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. 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. 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. 67. REMEMBER….. ALWAYS DRINK UPSTREAM OF THE HERD
  68. 68. Contact DEQ Well Construction Program at 517-241-1377

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