development of a regional well rehabilitation and replacement … · 2016. 11. 8. · development...

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


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


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


City Wells and Well

Fields


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?


Well Rehabilitation and Replacement Program

• Declining Water Tables


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%


• Assessment of Existing Well Conditions– Age

– Materials

– Methods of Construction

• Budget, budget, budget

• Proactive Well Maintenance


Well Rehabilitation andReplacement Program


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


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


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


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!


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


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


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


Driller’s Logs


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


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


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


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


Preliminary Condition Matrix Scoring


Steel Types

• Hard Red (pre-1942)

• Kai-Well (post-1945)

• Mild

• Copper-Bearing

• High Strength Low Alloy (HSLA)

• Stainless Steel


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+


Mineral Encrustation

Encrustation in Russell C Well(Likely Calcium Carbonate)

• Well Screen / Near-Well Zone

• Factors

– Water Chemistry

– Operation (Excessive Drawdown)


Corrosion

Garner B Well

EnlargedPerforations

Hole in Casing


Corrosion

Twin Springs Well

Severe Corrosion


Clogged Mill Slots Due to Corrosion


Biofouling inGarner B Well


Casing Alignment

Twin Springs Well

Severe Dogleg


Discharge Rate and Specific Capacity


Water Levels within the Screen

Top of Perforations


Pumping Test Analysis

Very LowWell Efficiency

Design Drawdown

DesignDischarge

Rate


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


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


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


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


Final Ranking

Worst Condition, Highest Probability of Successful Rehab at Relatively Low

Cost

Minimal or No Rehabilitation Recommended


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


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


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


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


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


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


Sustainable Yield Example

RECHARGE = 100PUMPING = 200

STORAGE CHANGE = - 100

Long Term Pumping Greater Than RechargeExceeds Sustainable Yield


Sustainable Yield Example

RECHARGE = 100PUMPING = 200

STORAGE CHANGE = 0

Artificial Recharge Increases Sustainable Yield

ARTIFICIALRECHARGE = 100


• 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?

development of a regional well rehabilitation and replacement … · 2016. 11. 8. · development...

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