1. Ranney Collector Rehabilitation Program
Purpose of discussion:
Overview of Program
Brief status re: Collector 3 project
Introduction to Collector 1 project
Board input/approval re: approach and next steps

2. Addressing Aging Infrastructure
Capital Improvement Plan:
~ 7 years to develop
approved November 2011
Ranney Collector Rehabilitation Program:
developed in parallel given importance of Collectors and lead-time to address

3. Ranney Collector Rehabilitation
One of highest priority areas:
50 years old and “worn”
Essential for service mission: high quality, reliable drinking water
Summer demands approaching capacity of 4 Collectors
(and one taken out of service for project)
Vastly different opinions on condition of laterals

4. Collector Well Schematic
Pumps & Pumphouse
(elevated for flood protection)
Reinforced Concrete Caisson
13-foot ID by 16-foot OD
Lateral Well Screens 12” Diameter, Perforated Carbon Steel, Variable Length (~ ft)
Two Tiers of Laterals (~60 – 80 ft bgs, ~30 ft below river bed)

5. Ranney Collector Rehabilitation Program
Original Goals:
Gather information re: condition of Collectors, especially laterals
Develop options and plan for longevity of system in most cost-effective manner
If possible, increase yield

6. Ranney Collector Rehabilitation Program
Three basic options:
Clean & rehab existing laterals
Install new laterals in existing Collectors
Install new Collectors (in entirety)

7. Summary of Assessment Work
1996 – Video Inspection of Caissons (Aqua Video)
2002 – Collector 2 Video Inspection of laterals and Pump Test (Reynolds, Inc.)
2003 – Ranney Collector Rehabilitation Feasibility Report (Winzler&Kelly)
2006 – Inspection and flow tests of laterals in Collectors 1, 1A, 3 and 4 (Collector Wells International)

8. Summary of Rehabilitation Work
District decided to start with Cleaning/Rehab Project: 2005 – Collector 2 lateral cleaning and rehabilitation (Collector Wells International) 2006 – Collector 2 Evaluation Final Report (Winzler&Kelly)

9. Summary of Rehabilitation Work
Results & Conclusions from Collector 2 Cleaning:
Provided valuable information re: condition of laterals
Increased specific capacity (yield) to limited extent
Based on economics, cleaning not recommended for other Collectors
Specific Capacity increased by 13%
Drawdown decreased by 1.8 feet
Cost savings <$1,000/year
Project cost was ~ $270,000
Cleaning does not increase longevity - laterals will still be 50-plus years old

10. Summary of Rehabilitation Work
Given results, District decided to pursue lateral replacement
development of groundwater model, geotech analysis and groundwater study (funded by DWR Local Groundwater Assistance Grant)
additional groundwater modeling and geotech work to plan new laterals at Collector 3
Installed new Laterals in Collector 3

11. Collector 3 Lateral Replacement Project
690 LF of new lateral installed
(vs. 430 LF of existing)
New stainless steel spiral-wound screens and stainless valves

12. Collector 3 Lateral Replacement Project
Yield:
4-5 MGD pre-replacement
~ 10 MGD post-replacement
Total cost = $1,066,000
Great learning experience
Results appear to have validated approach

13. Pump Station 3 Operational Data

14. Pump Station 3 Operational Data

15. Collector 3 Lateral Replacement Project

16. Collector 3 Lateral Replacement Project
Final Phase:
Install new pumps and motors (this year)
Install new transformer and upgrade electrical panel (this year)
Capstone: Assess performance and write final report

17. What’s Next? Determine next Collector to be rehabilitated
Install new laterals
Install new pumps/motors & electrical equipment
Assess and plan next steps

18. Where next? Recommend Collector1&1A:
Access - 1A is last “ground based” collector
Very good producer with flexible pumping arrangement
“Last chance” at water
Higher reliability (dedicated, below-ground 12kv electric feed)

19. Collectors 1&1A

20. Collector 1 - Background
Constructed in 1962
Sunk to depth 73-feet below river bed
Four pumps - two-350hp and two-200hp (two more than at other Collectors)
10 laterals located on two tiers (A and B)
Great producer, but problems with turbidity during winter

21. Collector 1- Background
Turbidity traced to three laterals
Ranney tried to correct problem by sealing and grouting laterals and installing manifold system
Did not work, and they agreed to construct Collector 1A and connect to Collector 1
All laterals in Collector 1 were “plugged”

22. Collector 1A - Background
Constructed in 1965
Sunk to depth 78-feet below ground
12 laterals on two tiers (A & B)
Total screen length 756 feet
Connected to Collector 1 via a 30-inch concrete- encased steel “siphon” pipe
Collector 1 has vacuum pumps connected to siphon pipe

23. Collectors 1&1A Connection

24. Collector 1A Assessment
1996 Aqua Video Inspection:
Concrete found to be in generally good condition
Siphon found to have corrosion on exterior but interior lining found to be good (as far as could see)
Valves and laterals highly encrusted with corrosion
Construction debris in caisson (which has been cleaned out)

25. 1996 Collector 1A Video Inspection

26. Collector 1 Assessment 2005 Pump Performance Test:
Pumps operating below performance curve
Pump 1.1 rebuilt
Pump 1.3 rebuilt and motor replaced
Pumps 1.2 and 1.4 have not been rebuilt or replaced

27. Collector 1 Assessment 2006 Collector Wells Inspection:
General condition good and well maintained
Did not assess Collector 1 laterals since “plugged”. Four laterals had some flow past plugs or valves
170 feet of 185 foot siphon line videoed with no obvious problems observed
Collector 1A laterals videoed with no obstructions or obvious deviations from horizontal observed

28. 2006 Collector Wells Inspection
All Collector 1A laterals had mineral deposits
Flow measured in each lateral
Observed specific capacity was high (rehabilitation of laterals would not likely produce additional flow)

29. Planning Work 2006 & 2008 Groundwater Modeling:
Recommended installing new laterals at Collector 3 first (done)
Recommended new laterals at Collectors 2 and 1/1A next
Model shows underutilized area downstream of 1A (meaning available water)

30. Collector 1 Work To-date
Carol, Dale, Barry, John Winzler & Pat Kaspari have been meeting to discuss findings and chart next steps
2012 Diver Survey
Established lateral locations, elevations and dimensions
Reassessed conditions of valves & plugs in both Collectors
2013 Collector 1 Valves
Installed two stainless valves on laterals B3 & B7 and blind flanges on all other laterals
2013 Initial Assessment Report
Collected and summarized data on Collectors 1&1A

32. Recommended Next Steps
Install 12 new stainless valves in Collector 1A
Develop work plan for testing laterals flow/water quality from laterals B3 & B7 in Collector 1
Test Collector 1 laterals (make sure short circuiting is not a problem)
Geotechnical assessment to map bedrock
Assess options for disposal of development water

33. Recommended Next Steps
Finalize layout of new laterals
287 feet needed to replace existing flow capacity. Will likely recommend installing 600 feet (4-150 ft or ft laterals)
Finalize what to do with siphon (cut off drop legs and replace vs. line it vs. leave alone)
Develop plans & specs and do CEQA (2014/15)
Install new laterals (2015/16)

34. Financing Estimated Project Cost $ 1,633,000 Funding Sources:
IRWMP Prop 84 Grant $ ,600
Advance Charges FY12/13 $ ,000
Current FY13/14 Charges $ ,000
Balance $ ,400
(customer charges, remaining DWFP Reserve, if any, or loan)