Development of a Regional Well
Rehabilitation and Replacement
Program
Russell J. Kyle, MS, PG, CHG
GEOSCIENCE Support Services, Inc.
Scott Rogers, PE
Riverside Public Utilities Water Division
American Water Works Association
California-Nevada Section
Annual Fall Conference 2014
Reno, Nevada
October 21, 2014
AWWA Annual Fall Conference 2014 – Reno, Nevada
Overview
• Background & Purpose
• Well Evaluation
– Preliminary Condition Ranking
– Final Rehabilitation Ranking
– Relevance to System
• Recommendations
AWWA Annual Fall Conference 2014 – Reno, Nevada
Background
• City of Riverside
– Population of 300,000
– 65,000 customer services
– 72 square miles
– Demands
• Maximum Day: 89 MGD
• Average Day Demand: 59 MGD
AWWA Annual Fall Conference 2014 – Reno, Nevada
Background
• City of Riverside
– Supply
• Groundwater Primary Supply
• Water Independency Importance
• Metropolitan Water District Alternative Supply
– Supply Costs
• $200 to $400 per acre-foot from groundwater
• $800 to $1,000 per acre-foot from MWD
AWWA Annual Fall Conference 2014 – Reno, Nevada
City Wells and Well
Fields
AWWA Annual Fall Conference 2014 – Reno, Nevada
Well Rehabilitation andReplacement Program
• Declining Production
Total Well Capacity
Year Percentage of Design Capacity
Annual Decrease
2009 79 % 6%
2010 74% 3%
2011 72% 3%
2012 69% 2%
2013 68% ?
Why develop a program?
AWWA Annual Fall Conference 2014 – Reno, Nevada
Well Rehabilitation and Replacement Program
• Declining Water Tables
Why develop a program?
Location2009-10 2010-11 2011-12 2012-13 2013-14
Average 2009-13
Spring Fall Spring Fall Spring Fall Spring Fall Spring Fall Spring Fall
Bunker Hill -2.3% 3.0% -8.1% 1.1% 3.7% -0.4% -7.7% 0.2% -5.1% ? -3.9% 1.0%
Colton basin 1.9% 8.9% 0.5% -1.6% 7.3% 0.2% -4.5% -0.7% -2.3% ? 0.6% 1.7%
Riverside North -3.6% -0.3% 24.5% 3.0% -61.9% -22.2% -10.0% -3.4% -11.1% ? -12.4% -5.7%
Riverside South 1.2% -0.1% 1.8% 0.7% -4.4% 0.6% -0.2% -1.6% -1.9% ? -0.7% -0.1%
AWWA Annual Fall Conference 2014 – Reno, Nevada
• Assessment of Existing Well Conditions– Age
– Materials
– Methods of Construction
• Budget, budget, budget
• Proactive Well Maintenance
Why develop a program?
Well Rehabilitation andReplacement Program
AWWA Annual Fall Conference 2014 – Reno, Nevada
Purpose and Scope
• “Develop a Plan for Well Rehabilitation and
Replacement that Ensures Adequate Ground
Water Supply to Meet Future Demands”
– Review and Summarize Well Historical Data
– Develop Well Rehabilitation, and
– Well Replacement Priority List
AWWA Annual Fall Conference 2014 – Reno, Nevada
Type of Wells by Construction Method
41 Wells (66%)
Cable Tool
1 Well (2%)Mud Rotary
20 Wells (32%)Fluid
Reverse Circulation
Rotary
66% of All City Wells were
Constructed by Cable Tool Methods
AWWA Annual Fall Conference 2014 – Reno, Nevada
Type of Wells by Steel Type
66% of All City Wells were
Constructed of “Hard Red”
and Kai-Well Steel
26 Wells (42%)
Red Steel
15 Wells (24%)
Kai-Well Steel
18 Wells (29%)
Mild Steel
3 Wells (5%)Copper-
Bearing Steel
AWWA Annual Fall Conference 2014 – Reno, Nevada
Wells by Age
14%(<20 Years
Old)
18%(20-40
Years Old)
15%(40-60
Years Old)17%
(60-80 Years Old)
36%(80-114
Years Old)
53% of All City Wells are Over
60 Years Old
Garner 1 and 4 are 115 Years Old!
AWWA Annual Fall Conference 2014 – Reno, Nevada
AWWA Annual Fall Conference 2014 – Reno, Nevada
Purpose
“Develop a Plan for Well Rehabilitation and
Replacement that Ensures Adequate Ground
Water Supply to Meet Future Demand”
– Review and Summarize Well Historical Data
– Develop Well Rehabilitation and Well Replacement Priority List
AWWA Annual Fall Conference 2014 – Reno, Nevada
Data Review and Well Histories
• Data Types Reviewed
– Downhole Video Survey Logs
– DWR Well Completion Reports
– City Records• Water Levels (static and pumping)
• Production
• Prior Well Rehabilitation Efforts
– CDPH Water Quality Database
– Drilling Companies
• Well Histories Summarized in Comprehensive Data Sheet
AWWA Annual Fall Conference 2014 – Reno, Nevada
Down Hole Video Surveys
• Used To Assess Condition of Casing And Screen– Verify Construction Details
• Casing and Screen Depths• Perforation Type• Reducers• Liners & Patches
– Encrustation and Clogging– Locate Ruptures– Floating Turbine Oil– Debris in Well– Identify Areas for Sidewall
Sampling
AWWA Annual Fall Conference 2014 – Reno, Nevada
AWWA Annual Fall Conference 2014 – Reno, Nevada
Driller’s Logs
AWWA Annual Fall Conference 2014 – Reno, Nevada
Summary of Well Construction,
Condition, and Operational
Details
Decision Tree for Well Rehabilitation or Replacement
Well Rehabilitation and Replacement Decision Tree
DEFINE PROBLEM
Score and Rank Well ProblemsAccording to Weighted Criteria
High Score = Numerous ProblemsLow Score = No Problems
Well Information Data Sheet
Probability of Successful Rehabilitation / Repair?
Y
N
Reasonable Cost of Rehabilitation / Repair?
Y
N
Consider Well Rehabilitation
High Relevancy to the System?
N
Consider Well Replacement
Y
GEOSCIENCE Support Services, Inc. 23-Dec-13
AWWA Annual Fall Conference 2014 – Reno, Nevada
Ranking Matrix Methodology• Develop Scoring Criteria
– Construction
– Physical Inspection
– Operation alConcerns (i.e., Water Levels and Specific Capacity)
• Scoring (0-3)
• Weighting Factor (1-3)
• Preliminary Condition Score and Rank
– Highest Rank Equates to Most Problematic Well
• Final Rehabilitation Score and Rank
– Probability of Successful Rehabilitation (Higher = More Successful)
– Rehabilitation Cost (Higher = Less Expensive)
– Cost for Repair (Higher = Less Expensive)
• Total Score and Final Rehabilitation Rank
– Higher Rank is Problematic Well with Greatest Chance of Successful, Low-Cost Rehabilitation
• Relevancy to System Overlay
AWWA Annual Fall Conference 2014 – Reno, Nevada
Preliminary Condition Ranking• Construction:
– Well Age– Well Casing and Screen Steel Type– Well Screen Perforation Type– Remaining Well Life– Potential for Underdevelopment
• Physical Inspection:– Structural Issues– Risk of Collapse– Casing Ruptures and/or Holes– Fill Present in the Well– Biofouling and/or Mineral Encrustation
• Operational Concerns:– Specific Capacity Trends– Water Levels within the Well Screen– Pumping of Sand and/or Gravel
0
50
100
150
200
250
300
350
400
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
Dis
char
ge R
ate
, gp
m
Spe
cifi
c C
apac
ity,
gp
m/f
t
Discharge Rate and Specific Capacity
Electric Street Well
Discharge Rate
Specific Capacity
Attach
men
t D
May 2007: Bottom of Well Plugged at 305 ft bgs
AWWA Annual Fall Conference 2014 – Reno, Nevada
Preliminary Condition Matrix Scoring• Scoring Criteria
– Construction
– Physical Inspection
– Monitoring
• Scoring (0-3)
– 0: No Problem
– 1: Mild Problem
– 2: Moderate Problem
– 3: Severe Problem
• Importance (Weighting) Factor (1-3)
– 1: Low Importance
– 2: Medium Importance
– 3: High Importance
AWWA Annual Fall Conference 2014 – Reno, Nevada
Preliminary Condition Matrix Scoring
AWWA Annual Fall Conference 2014 – Reno, Nevada
Steel Types
• Hard Red (pre-1942)
• Kai-Well (post-1945)
• Mild
• Copper-Bearing
• High Strength Low Alloy (HSLA)
• Stainless Steel
AWWA Annual Fall Conference 2014 – Reno, Nevada
Expected Well Life by Steel Type
Steel Type Expected Well Life (Years)
Hard Red & Kai-Well (Cable Tool) 10-100+
Mild Steel (Wire-Wrap) 10-15
Mild Steel (Pipe-Based) 20-30
Copper-Bearing 30-45
High-Strength Low-Alloy (Corten) 45-60
304L Stainless 75-90
316L Stainless 90+
AWWA Annual Fall Conference 2014 – Reno, Nevada
Mineral Encrustation
Encrustation in Russell C Well(Likely Calcium Carbonate)
• Well Screen / Near-Well Zone
• Factors
– Water Chemistry
– Operation (Excessive Drawdown)
AWWA Annual Fall Conference 2014 – Reno, Nevada
Corrosion
Garner B Well
EnlargedPerforations
Hole in Casing
AWWA Annual Fall Conference 2014 – Reno, Nevada
Corrosion
Twin Springs Well
Severe Corrosion
AWWA Annual Fall Conference 2014 – Reno, Nevada
Clogged Mill Slots Due to Corrosion
AWWA Annual Fall Conference 2014 – Reno, Nevada
Biofouling inGarner B Well
AWWA Annual Fall Conference 2014 – Reno, Nevada
Casing Alignment
Twin Springs Well
Severe Dogleg
AWWA Annual Fall Conference 2014 – Reno, Nevada
Discharge Rate and Specific Capacity
AWWA Annual Fall Conference 2014 – Reno, Nevada
Water Levels within the Screen
Top of Perforations
AWWA Annual Fall Conference 2014 – Reno, Nevada
Pumping Test Analysis
Very LowWell Efficiency
Design Drawdown
DesignDischarge
Rate
AWWA Annual Fall Conference 2014 – Reno, Nevada
Operational Concerns
When Wells Are Pumped
Continuously,In Some Cases Cementation Occurs In The
Near Well Zone
Increasing Well Losses
Cementation in Near-Well
Zone
Mo
st P
rob
lem
atic
Leas
t
AWWA Annual Fall Conference 2014 – Reno, Nevada
Final Rehabilitation Ranking
• Probability of Successful Well Rehabilitation and/or Repair– Degree of Structural Problems– Degree of Biofouling and/or Mineral Encrustation– Stable Water Levels?
• Rehabilitation Cost– Rehabilitation Impossible– Chemical and Mechanical– Mechanical Only– Brushing and Disinfection
• Cost of Repair– Liner with Artificial Filter Pack– Liner Only– Casing Patches– No Repair
AWWA Annual Fall Conference 2014 – Reno, Nevada
Final Rehabilitation Matrix Scoring• Scoring Criteria
– Probability of Successful Well Rehabilitation and/or Repair
– Rehabilitation Cost
– Repair Cost
• Scoring (0-3)
– 0: Worst Case
– 1: Moderate Case
– 2: Mild Case
– 3: Best Case
• Importance (Weighting) Factor (1-3)
– 1: Low Importance
– 2: Medium Importance
– 3: High Importance
AWWA Annual Fall Conference 2014 – Reno, Nevada
Final Rehabilitation Matrix Scoring
• The “Kill Switch”:
– A Well Found to Have a High Risk of Casing Collapse
Was Scored “0”, Dropping it to the Bottom of the
Ranking Table and Flagging it for Future Replacement
0
20
40
60
80
100
120
140
0
2
4
6
8
10
12
14
16
Cum
ulat
ive
Co
st In
Tho
usan
ds O
f Do
llars
Th
ou
san
ds
Of
Do
llars
Cumulative Cost
Typical Costs For Well Rehabilitation
Add ~$50,000 for acid treatment
Add ~$10,000 for Well Patch1
Add ~$175,000 for Well Liner21 5 ft, 16-inch HSLA 2 800 ft, 14-inch x 5/16-in. wall HSLA
AWWA Annual Fall Conference 2014 – Reno, Nevada
Final Ranking
Worst Condition, Highest Probability of Successful Rehab at Relatively Low
Cost
Minimal or No Rehabilitation Recommended
AWWA Annual Fall Conference 2014 – Reno, Nevada
Relevance to the System
• Relevance to the System is an Overlay that Takes
into Account Criticality of Each Well to System
– Required Input from City Planners & Operators
– Scoring 0-3 (3 = Highly Relevant)
• Examples:
– Well Provides Feedwater to Treatment Plant
– Well is Critical to Meeting Demand in Particular Area
AWWA Annual Fall Conference 2014 – Reno, Nevada
Results
• Well Rehabilitation Ranking Table
– Not Static and Will Require Periodic Update
• Changing Hydrogeologic Conditions
• Changing Demand
• New Data
• Increasing Age of Wells
Results – Russell CCriteria Score Score Description Basis
Age 1 Mild Problem 10-30 Years
Potential for Being Undeveloped 2 Moderate Problem Mud Rotary
Steel Type 3 Severe Problem Mild Steel
Perforation Type 3 Severe Problem Mild Steel Wire Wrap
Remaining Life 2 Moderate Problem 25-15 Years
Structural Issues 1 Mild Problem Exfoliation of Steel / Telescoping
Risk of Collapse 1 Mild Problem Exfoliating Casing / Minor Holes
Biofouling / Encrusting 3 Severe Problem Perforations Largely Obscured / Major Drop in Specific Capacity
Casing / Screen Ruptures or Holes 1 Mild Problem Minor Structural Issues
Fill 0 No Problem <10 ft
Pumping Sand or Gravel 1 Mild Problem Minor or Sporadic
Water Levels Below Screen 0 No Problem -
Specific Capacity Trend 0 No Problem No Trend
Problem Weighted Score = 43Preliminary Rank = 41 of 60
Results – Russell CCriteria Score Score Description Basis
Probability of Successful Rehabilitation 0 High Risk of Well Collapse / Low Probability of Success
Mild Steel Wire-Wrap / Aggressive Rehabilitation Needed
Rehabilitation Cost 0 Rehabilitation Impossible Severe Clogging
Cost for Repair or Liner 3 No Repair Required Mild Steel
Total Score = 0
Final Rank = 46 of 60 (Lowest Rank Possible)
“Candidate for Replacement”
Results – Moore GriffithCriteria Score Score Description Basis
Age 3 Severe Problem >50 Years
Potential for Being Undeveloped 1 Mild Problem Cable Tool
Steel Type 1 Mild Problem Hard Red / Kai-Well
Perforation Type 2 Mild Problem Mills Knife
Remaining Life 3 Severe Problem <5 Years
Structural Issues 1 Mild Problem Steel Exfoliation
Risk of Collapse 1 Mild Problem Exfoliating Casing
Biofouling / Encrusting 2 Moderate Problem Some Perforations Covered / Tubercles
Casing / Screen Ruptures or Holes 0 No Problem No Holes
Fill 2 Moderate Problem 20 – 50 ft
Pumping Sand or Gravel 2 Moderate Problem Pump Replacements / Repair
Water Levels Below Screen 1 Mild Problem Pumping Levels at Top of Screen
Specific Capacity Trend 0 No Problem No Trend
Problem Weighted Score = 45Preliminary Rank = 38 of 60
Results – Moore GriffithCriteria Score Score Description Basis
Probability of Successful Rehabilitation 3 Significant Improvement Possible Stable Water Levels and Specific Capacity but Declining Yield
(Well Losses)
Rehabilitation Cost 1 Chemical and Mechanical Rehabilitation
-
Cost for Repair or Liner 2 Patch Patching of Enlarged Perforations May be Necessary
Total Score = 4,050
Final Rank = 4 of 60Enlarged Mills-Knife
Perforation
AWWA Annual Fall Conference 2014 – Reno, Nevada
Recommendations
• Long-Term Plan to Maintain Ground Water Supply
– Annual Well Rehabilitation Program
– Annual Well Replacement Program
– Ranking Table Updates
• Rigorous Ground Water Monitoring
• Ground Water Management
AWWA Annual Fall Conference 2014 – Reno, Nevada
Well Maintenance and Replacement
• Operational
– Avoid Long Idle Time
– Avoid Continuous Operation
• Well Rehabilitation
– 2 to 10 per year (Depending on Steel Type)
• Well Replacement
– 1 to 2 per year
AWWA Annual Fall Conference 2014 – Reno, Nevada
Rigorous Monitoring
Develop an Ongoing Methodology to
Monitor Key Well Parameters to Ensure or
Improve Ground Water Supply and Minimize
Well Rehabilitation or Replacement Efforts
AWWA Annual Fall Conference 2014 – Reno, Nevada
Recommendations
Determine and Meet Sustainable Yield
• Annual Extractions That:
– Do Not Exceed Recharge on Long-Term Basis
– Do Not Permanently Lower The Water Table to an
Undesirable Level
– Do Not Allow Degradation of Water Quality
– Do Not Create Subsidence
AWWA Annual Fall Conference 2014 – Reno, Nevada
Sustainable Yield Example
RECHARGE = 100PUMPING = 200
STORAGE CHANGE = - 100
Long Term Pumping Greater Than RechargeExceeds Sustainable Yield
AWWA Annual Fall Conference 2014 – Reno, Nevada
Sustainable Yield Example
RECHARGE = 100PUMPING = 200
STORAGE CHANGE = 0
Artificial Recharge Increases Sustainable Yield
ARTIFICIALRECHARGE = 100
AWWA Annual Fall Conference 2014 – Reno, Nevada
• Annual Meeting
• Analysis of Hydrographs
• Recommended Pumping Schedule
• Ground Water Basin Model
• Annual Report
• Constant Updating of Pumping Schedule
• Update Rehabilitation and Replacement Ranking Every ~5 Years
Water Audit
Questions?