HomeMy WebLinkAboutPackets - Council Packets (1538) AGENDA
ORO VALLEY TOWN COUNCIL JOINT STUDY SESSION
WITH ORO VALLEY WATER UTILITY COMMISSION, MARANA TOWN
COUNCIL, AND METRO DOMESTIC WATER IMPROVEMENT DISTRICT
BOARD OF DIRECTORS
APRIL 28, 1999
ORO VALLEY TOWN COUNCIL CHAMBERS
11,000 N. LA CANADA DRIVE
CALL TO ORDER -AT OR AFTER 7:00 P.M.
ROLL CALL
1. INA ROAD WPCF RECLAIMED WATER DISTRIBUTION SYSTEM
FEASIBILITY STUDY - PIMA COUNTY
POSTED:
4-23-99
4:30 p.m.
ih
TOWN OF ORO VALLEY
COUNCIL COMMUNICATION MEETING DATE: April 28, 1999
TO: HONORABLE MAYOR & COUNCIL
FROM: David G. Hook, P.E.
Water Utility Director
SUBJECT: Ina Road WPCF Reclaimed Water Distribution System Feasibility
Study- Pima County
SUMMARY:
After some discussion in the fall of 1998, the Mayor and Council directed Oro Valley
Water Utility (OVWU) staff to give preferred status to the reclaimed water option involving
Pima County's concept to expand treatment facilities at the Ina Road wastewater
treatment plant and extend a distribution facility up the CDO Wash to Oro Valley. This
direction was consistent with the recommendation forwarded to Mayor and Council by the
Water Utility Commission (Commission) and was primarily based on the appearance of
Pima County's option providing the best timetable and cost ranges for the Oro Valley
community.
Subsequently, staff has coordinated with Pima County staff and consultants as they
prepared the feasibility report on this concept. Attached for your reference is a scope of
work for that contract between Pima County and Malcolm Pirnie. Contact with the
Bureau of Reclamation was also initiated regarding the effluent rights awarded to the
Indian nations through the SAWRSA settlement. Preliminary information discussed
during the development of the report indicated that favorable feasibility findings were
highly probable, with costs per acre-foot below that of Tucson's reclaimed water sales.
Recently, the City of Tucson initiated litigation with Pima County regarding the County's
efforts to implement the Ina Road reclaimed water concept. This has delayed the
issuance of the County's report on the matter as well as staffs ability to report back to the
Commission and the Mayor and Council.
Originally scheduled for release in February 1999, the County is now prepared to present
the findings of their feasibility study at this joint meeting to the officials of Oro Valley,
Marana and the Metropolitan Domestic Water Improvement District. The Oro Valley
Water Utility Commission has been invited to the Study Session this evening to hear the
presentation.
FISCAL IMPACT:
The fiscal impact of this reclaimed water option is expected to be discussed by Pima
County staff during their presentation. Of particular interest to OVWU staff will be the
methodology used by the County to distribute costs of treatment. Staff desires to
understand that regular wastewater ratepayers will not subsidize the treatment and
TOWN OF ORO VALLEY
COUNCIL COMMUNICATION PAGE 2 OF 2
delivery of reclaimed water to golf courses. Additionally, staff is anxious to understand
the assumptions of the County regarding the cost of water rights and assumptions
regarding the operation and maintenance of the distribution system within Oro Valley as
the reclaimed water is delivered to the irrigation customers.
RECOMMENDATIONS OF THE WATER UTILITY COMMISSION:
The Commission has not heard or discussed the County's report on this reclaimed water
option. The Commission stands ready to take the information provided by the County
and return to the Mayor and Council at its earliest opportunity with a formal
recommendation on this matter.
ATTACHMENTS:
1. Scope of Work between Pima County and Malcolm Pirnie for reclaimed water
feasibility study.
SUGGESTED MOTION:
None provided.
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PIMA COUNTY WASTEWATER MANAGEMENT DEPARTMENT
INA ROAD WPCF RECLAIMED WATER DISTRIBUTION SYSTEM
FEASIBILITY STUDY
SCOPE OF PROFESSIONAL SERVICES
This scope of professional services has been prepared based on a draft scope of work
developed by Pima County Wastewater Management Department (PCWMD) and from
discussions with PCWMD staff on Friday, September 25, 1998. This scope of services is
composed of the following sections:
I. Background
II. Scope of Work
III. Project Budget
IV. Project Schedule
I. BACKGROUND
Pima County, the Metropolitan Domestic Water Improvement District (MDWID), the
Flowing Wells Irrigation District (FWID), and the Towns of Oro Valley and Marana are
interested in preparation of a feasibility study to assess potential development of a reclaimed
water supply and distribution system originating at the Ina Road Water Pollution Control
Facility(WPCF). The proposed reclaimed water distribution system would be developed to
serve three general areas: the Canada del Oro (CDO) valley, area along the Santa Cruz River
within the Town of Marana, and selected areas along the Rillito Creek from Interstate
Highway 10 (I-10) to the vicinity of Craycroft Road.
The PCWMD scope of work included conducting a feasibility study for a distribution system
to convey 20,000 acre-feet per year of Ina Road WPCF effluent through the proposed system
to various reuse points. The feasibility study would include: a review of regulatory
requirements, a reclaimed water market study, a pipeline route study, a treatment and storage
capacity evaluation, a conceptual design, system optimization, cost opinions for pipelines and
facilities, and a rate analysis. For the purpose of this study, the scope of work was developed
assuming that the stake holders will be able to obtain agreements to utilize effluent. If
agreements are not obtained by stake holders for effluent use, the distribution system will be
sized for the volume of Pima County-controlled effluent, which is estimated to be
approximately 7,000 acre-feet per year.
The work will culminate in the production of a report that summarizes the results of each task ,
and presents backup information in appendices.
P971562 - 1 - October 1998
II. SCOPE OF WORK
In response to PCWMD's request for a detailed scope of work, schedule, and budget during
our September 25 meeting, Malcolm Pirnie has prepared a scope of work to accomplish the
Ina Road WPCF Reclaimed Water Distribution System Feasibility Study as described by
PCWMD. We recognize that the project goals must be completed over an expedited schedule
to provide decision-makers with the feasibility study results on an "as soon as possible" basis.
Because of the accelerated schedule for the project, the scope of work was developed using
project meetings rather than technical memoranda to convey information on work progress
and to solicit comments from PCWMD staff and share holders.
The scope of work is organized into the following seven tasks:
1. Conduct Preliminary Investigations
2. Perform Route Study and Develop Conceptual Designs
3. Develop Reclaimed Water Storage and Recovery Alternatives
4. Evaluate Wastewater Treatment
5. Optimize Conceptual Design and Perform Rate Analysis
6. Prepare Report
7. Perform Project Management
TASK 1 CONDUCT PRELIMINARY INVESTIGATIONS
The major parameters and informational resources needed to conduct the study will be
assembled and summarized in Task 1. This task is structured to develop information
necessary for the analysis of treatment, storage, and conveyance of reclaimed water within
the study area.
Subtask 1.1 - Determine the Study Area Boundary
In consultation with PCWMD and the stake holders, the study area boundaries for the project
will be delineated, described, and mapped. The study area is expected to generally
correspond to the areas associated with CDO valley, the Rillito Creek from I-10 to Craycroft
Road, and the Santa Cruz River area within the Town of Marana. A GIS-based map of the
study area with available topographic information will be developed and used as a base map
for overlay of potential reclaimed water users and infrastructure options throughout the
project.
Subtask 1.2- Identify Potential Reclaimed Water Users and Characterize Water Use
An inventory of existing and potential reclaimed water users within the study area will be
developed for the categories presented in the Regional Effluent Utilization Plan, Phase B
(Malcolm Pirnie, 1995) and shall include golf courses, parks, schools, agricultural and
commercial properties, and street landscape irrigation. Information on water use by each of
these facilities will be developed based on available information from the Arizona Department
P971562 -2- October 1998
of Water Resources (ADWR) and supplemental records, if required, from each user.
Interviews with water users will be conducted to determine individual water use
characteristics and requirements. Time for up to 25 such meetings will be budgeted.
Historical water use over the past five years will be documented for each water user in terms
of annual water use. Accurate documentation of variations in water use, which can be
significant for all users, but most significant for agriculture and turf irrigation facilities, will
also be very important for development and analysis of reclaimed water delivery system
alternatives. For this reason, peak water demands, time of occurrence, and monthly water
demand information will be obtained for each user and entered into a database for use
throughout the project. Potential direct recharge facilities within the study area, at sites
established in the Regional Recharge Plan(ADWR, 1998), will also be identified, along with
water users with potential interest in participating in the recharge projects.
Locations of the water users will be accurately added to the GIS project base map, and
elevations of the user's facilities, and potential reclaimed water delivery points for each user
will be identified.
Subtask 1.3- Prepare Demand Projections and Determine Flow Parameters
Total annual water demand projections and potential reclaimed water demand projections will
be calculated and tabulated for each potential reclaimed water user based on available
information from ADWR. Average and peak reclaimed water use projections for potential
users will be tabulated on an annual basis for the first 10 years and at five-year intervals
thereafter through a 30-year total planning horizon.
Reasonable factors derived from historical water use data will be used to characterize the total
annual demand projections in terms of average and peak demands for each user.
Seasonal/monthly demand patterns will be used to estimate required storage volumes for
potential reclaimed water users with significant demand variations. Both in-system and on-
site storage will be assessed.
Subtask 1.4-Assess Water Quality Issues
Existing water supplies for potential reclaimed water users will be identified. Key water
quality parameters will be compared with water quality targets for the proposed biological
nutrient removal secondary treatment train at the Ina Road WPCF. Any water quality
concerns for direct use of reclaimed water by potential users and prospective recharge will
be summarized. Water quality of secondary wastewater effluent from the existing pure
oxygen activated sludge treatment train at the Ina Road WPCF will also be evaluated for use
in the reclaimed system.
Subtask 1.5- Prepare a Regulatory Overview
Federal, State, and local regulations affecting the construction and operation of reclaimed
water treatment, storage, and conveyance facilities will be summarized. The overview will
focus on regulatory requirements for wastewater reuse, conveyance system construction, and
operation of underground storage and recovery facilities for reclaimed wastewater.
P971562 -3 - October 1998
Reclaimed water quality requirements for underground storage and recovery and aquifer
protection requirements will be examined. Potential regulatory permitting and construction
requirements for pipelines within washes will also be addressed in this subtask.
TASK 2 PERFORM ROUTE STUDY AND DEVELOP CONCEPTUAL
DESIGNS
Based on the results of the baseline data development in Task 1 regarding potential reclaimed
water uses, alternative routes for reclaimed water delivery infrastructure extensions to serve
identified potential uses will be developed for technical, and conceptual cost analyses in
consultation with PCWMD. The most feasible alternative delivery routes will be selected
through cost-based and non-cost-based analyses.
Subtask 2.1 - Identi:fy Alternative Routes
In close coordination with PCWMD, three alternative reclaimed water delivery pipeline
corridors will be evaluated:
• CDO Valley;
• Along the Rillito Creek between 1-10 and Craycroft Road; and
• Santa Cruz River within the Town of Marana.
Up to three potentially feasible reclaimed water delivery system routes will be delineated for
each service area to serve potential users identified in Task 1. The alternative routes will be
based on the following:
• Alternative 1: Use existing public road rights-of-way;
• Alternative 2: Use existing public sewer and utility easements generally
located along the Santa Cruz River, the CDO Creek, and the Rillito Creek;
and
• Alternative 3: Use existing public rights-of-way of the County Flood Control
District in river and creek bottoms within the Santa Cruz River, the Rillito
Creek, and the CDO Creek.
Physical and operational constraints will be described for each alternative. Physical
constraints will include right-of-way/easement availability, existing utility conflicts, washes,
hills, rock outcroppings, traffic considerations, compressible soils, archaeological sites, and
construction impacts. Operational constraints include hydraulic requirements, capacity
limitations, seasonal/scheduling delivery requirements, and permitting issues.
Subtask 2.2- Develop Conceptual Level Design of Alternative Routes
A conceptual-level design will be completed for each of the alternative delivery system routes
identified in Subtask 2.1 within each of three service areas. Each conceptual-level design will
include:
P971562 -4- October 1998
• Schematic plan of the alignment using Arcview GIS-based mapping and
topographic data provided by Pima County Technical Services.
• Identification and location of specific infrastructure requirements, including
pumps, turnouts, storage facilities, and treatment facilities (if required). Two
delivery scenarios will be evaluated:
1) Maximum capacity of 20,000 acre-feet per year.
2) Maximum capacity of 7,000 acre-feet per year.
• Elevations and current land ownership (i.e., County, State, City, or private)
based on GIS data prepared by Pima County Technical Services and easement
requirements based on County Assessor maps.
• Pipelines will be sized to meet maximum day demands, and turnout facilities
will be sized to meet specific user hydraulic and demand requirements.
The conceptual-level design will include the evaluation of the "primary" pump station and
main reservoir located at or in the vicinity of the Ina Road WPCF. Facilities will be sized and
cost opinions prepared based on water demand information identified in Task 1.
Subtask 2.3- Prepare Preliminary Cost Opinions for Alternative Routes
Conceptual-level cost opinions will be prepared for each alternative delivery system route.
The estimates will include probable construction costs, estimated land acquisition and
easement costs, and opinions of annual operating and maintenance costs. Ina Road WPCF
power generation facilities will be evaluated for estimating power costs for the primary
pumping station. Additional preferred power sources will be evaluated and costs estimated.
Subtask 2.4- Analyze Alternative Routes
A comparative matrix analysis of the alternative reclaimed water delivery routes will be
performed for each of the three delivery corridors based upon a series of cost-based and non-
cost evaluation criteria and weighting factors developed in cooperation with PCWMD. Cost-
based evaluations will be performed on the basis of calculated estimated unit costs of
reclaimed water. Unit costs for reclaimed water will be based on total cost opinions for each
alternative divided by the total water demand for the specific service area. Non-cost
evaluations will be performed by scoring individual segments of pipeline for each alternative
based on the non-cost criteria including: utility conflicts, right-of-way acquisition
requirements, traffic impacts, flood plain conflicts, residentiaUcommercial impacts,
archaeological sites, and environmental impacts. Utility maps will be collected from major
utility providers including PCWMD, Tucson Electric Power, Trico Electric, MDWID, Tucson
Water, Jones Intercable,U.S. West Communications, and Southwest Gas. County Assessor's
maps will be obtained to evaluate right-of-way.
Alternative delivery routes will have cost-based scores and non-cost-based scores combined
to assign final rankings among route alternatives for each of the three service areas. The
routes with the lowest scores will be selected as the preferred delivery routes.
P971562 -5 - October 1998
TASK 3 - DEVELOP RECLAIMED WATER STORAGE AND RECOVERY
ALTERNATIVES
Subtask 3.1 -Develop Reclaimed Water Storage Alternatives
Based on the results of the Task 2 route study, potential locations and sizings of surface
storage reservoir facilities will be determined. The main reservoir will be located at or in the
vicinity of the Ina Road WPCF. The number and sizes of reservoirs will be determined by
the results of Tasks 1 and 2.
Subtask 3.2-Develop Underground Storage and Recovery Alternatives
Locations for potential underground storage and recovery projects will be determined based
on information presented in the Regional Recharge Plan (ADWR, 1998). An evaluation of
the use of the sand and gravel pit located north of the Ina Road WPCF will be included as a
part of the scope. Evaluations of potential recharge sites will be based on the review of the
Arizona Department of Environmental Quality(ADEQ) Aquifer Protection Permit (APP) and
ADWR Underground Storage and Recovery (IJS&R) permit for the Sweetwater Recharge
Facility,which is a similar facility that is currently operating. Review of the Sweetwater APP
and US&R permit will provide insight into ADWR and ADEQ requirements for the operation
of a new reclaimed water underground storage and recovery facility. No new hydrogeological
evaluations will be performed as part of this task. Hydrogeological evaluations are ultimately
needed to determine the feasibility of conducting recharge at any location.
TASK 4 EVALUATE WASTEWATER TREATMENT
An evaluation of the proposed expansion and upgrade to the Ina Road WPCF will be
performed to determine the likelihood that effluent quality from the new biological nutrient
removal(BNR) secondary process train will be sufficient for water uses described in Task 1.
Tertiary treatment requirements for secondary effluent produced at the Ina Road WPCF will
be evaluated based upon a comparison of wastewater reuse regulations and projected effluent
qualities after the Ina Road WPCF expansion. The BNR process is projected to produce up
to 12.5 million gallons per day (MGD) or approximately 14,000 acre-feet per year(AF/yr).
Approximately 6,000 AF of reclaimed wastewater would be required from the existing Ina
Road pure oxygen activated sludge treatment train to provide the total planned reclaimed
delivery capacity of 20,000 AF/yr.
Subtask 4.1 - Evaluate the Ina Road WPCF Expansion
An evaluation of the Ina Road WPCF will be performed to determine the ability of the
existing treatment plant and the proposed expansion to meet the water quality and quantity
requirements for reclaimed water users described in Task 1. The Aquifer Protection Permit
(APP) application for the Ina Road WPCF will be obtained and reviewed to evaluate the
existing facility. The Ina Road WPCF Expansion Design Report will be obtained and
reviewed to compare the potential effluent quality from the proposed BNR facility to
reclaimed water quality goals described by Task 1.
P971562 -6- October 1998
Subtask 4.2-Evaluate Potential Tertiary Treatment for Reclaimed Water
Tertiary treatment of secondary effluent from the existing Ina Road WPCF will be evaluated
to provide the potential make-up volume of total reclaimed wastewater to meet potential
demand. Tertiary treatment will be based on water quality requirements defined by Task 1.
Cost opinions will be developed for potential tertiary treatment of secondary effluent for the
make-up volume and for potential tertiary treatment from the BNR process based on results
of the evaluation presented in Subtask 4.1.
TASK 5 SUMMARIZE CONCEPTUAL DESIGN AND PERFORM RATE
ANALYSIS
A conceptual design of the entire reclaimed water treatment, storage, and delivery system will
be developed from information presented in Tasks 2, 3, and 4. The conceptual design will
include GIS-based plan maps with locations of, preliminary sizing of, and cost opinions for
all proposed reclaimed system components. The cost opinion information will be used to
perform a rate analysis for reclaimed water. Task 5 will be completed in four subtasks
described below.
Subtask 5.1 - Conceptual Design Plan
The conceptual design plan will be developed using GIS-based mapping to illustrate the
horizonal alignment of the recommended pipeline routes, storage facilities, booster facilities,
and potential recharge facilities. The plan will identify existing major geographic features,
such as topography, waterways, and roads, based on GIS information provided by Pima
County Technical Services. Major underground features, such as large pipelines and
communication lines will also be illustrated on plans. Locations of underground utility lines
will be determined from information provided by local utility companies.
Subtask 5.2-Develop Cost Opinions
Construction and operations and maintenance (O&M) cost opinions based on the conceptual
design will be developed. The cost opinions will include material take-offs and best available
costing data from recent available bid tabulations, standard construction estimating manuals,
manufacturers' quotes, and engineering judgment. Representative cost factors for
contractor's overhead and profit, engineering design and construction support fees, right-of-
way acquisition, power costs, maintenance costs, and contingencies will be included and
documented. Cost opinions will be based on 1999 dollars.
Subtask 5.3- Perform Rate Analysis
Based on the cost opinions developed from Subtask 5.2, a financial rate analysis will be
performed to determine estimated unit costs for reclaimed water using four pricing scenarios:
• Individual rates for each leg of the system (CDO, Rillito, and Santa Cruz)
without defining individual charges based on elevation zones.
P971562 -7- October 1998
• Individual rates for each leg of the system with rates adjusted along the system
to account for pumping costs at different elevation zones.
• Single flat unit reclaimed wastewater rate for all customers.
• Fixed rate schedule with a commercial rate based on the rate analysis
presented in this task and a public-benefit rate that would be developed for the
balance of reclaimed water delivered to facilities that benefit the public.
TASK 6 PREPARE REPORT
The findings and results of Tasks 1 through 5 will be summarized and incorporated into one
project report. The preparation of the project report will be conducted in three subtasks.
Subtask 6.1 - Prepare Draft Report
A draft report will be prepared that includes summary text, figures, maps, plans, tables, and
other exhibits that summarize the execution and findings of the project. The draft report will
identify the following key elements of the project:
• Project Study Area, Goals, and Planning Horizon
• Locations of Potential Reclaimed Water Users and Associated Demands
• Alternative Pipeline Routes and Facility Locations Investigated
• A Discussion of the Optimal Treatment, Storage, Recharge, and Delivery
Systems
• A Discussion of the Cost Opinions for Recommended Facilities
• A Discussion of the Rate Analysis
The draft report will be organized as an executive summary. Summaries of each task and
detailed technical support documentation will be provided as appendices to the draft report.
Fifteen copies of the draft study report and appendices will be submitted to PCWMD and the
stake holders for review and comment. An oral presentation of the project results will be
conducted at the time that the draft report is provided.
Subtask 6.2-Prepare and Submit Final Report
Upon receipt of a written summary of PCWMD review comments, a single copy of the final
report will be prepared that incorporates comments provided by PCWMD and the share
holders on the draft report. Upon PCWMD approval of the final report, thirty copies of the
final report will be prepared and submitted to PCWMD.
P971562 -8- October 1998
TASK 7 PROJECT MANAGEMENT
Task 7.1 - Coordination and Monitoring
Throughout performance of the project, overall project management activities will include
coordination of project tasks, monitoring project budget and schedule, and facilitating
technical project meetings.
Task 7.2 - Technical Project Meetings
Technical project meetings will be used to update PCWMD on project approach and findings
and to provide a vehicle to solicit comments in lieu of submission of written technical
memoranda. Interim technical memoranda will not be produced in order to facilitate an
accelerated project schedule. Malcolm Pirnie will prepare and distribute agendas for each
project meeting. Malcolm Pirnie will also prepare presentation materials and task summaries
for each project meeting. Comments from PCWMD staff will be solicited during each project
meeting, or a written summary of review comments will be provided within one week
following project meetings to maintain the project schedule. Malcolm Pirnie will prepare
meeting minutes that describe the issues raised during each technical project meeting and the
agreed approaches to ensuing project tasks. Four technical project meetings are proposed
for the course of this feasibility study:
First Project Meeting. The initial project meeting will be held within one week
following Notice-to-Proceed. The first project meeting will be used to outline the
project goals, approach, and schedule and to define key assumptions.
Second Project Meeting. The second project meeting will be conducted upon
completion of Task 1 (Conduct Preliminary Investigations). Task 1 results concerning
regulatory requirements and reclaimed water markets will be presented and discussed
with respect to ensuing tasks. Design criteria for conceptual pipelines will be
presented based on data collected in Task 1. Conceptual routes for Task 2 will be
discussed.
Third Project Meeting. The third project meeting will be held following completion
of Tasks 2 (Perform Route Study), 3 (Develop Reclaimed Water Storage and
Recharge Alternatives), and 4(Evaluate Wastewater Treatment). Results of the route
study will be presented along with recommendations for preferred alignments.
Reclaimed water quality requirements and treatment goals will be presented along
with results of the evaluation of the existing Ina Road WPCF. Results of the
evaluations of reclaimed water requirements for storage capacity and the
configuration of storage facilities will be presented. The conceptual layout for
reclaimed water treatment, storage, and transmission facilities will be presented for
the basis of Task 5.
Fourth Project Meeting. The fourth project meeting will be held following
completion of Task 5 (Summarize Conceptual Design and Perform Rate Analysis).
P971562 -9- October 1998
Results of these financial investigations will be discussed to develop recommendations
for the draft report. Report production and review schedules will be addressed.
Task 7.3 - Project Presentations
At the request of PCWMD, Malcolm Pirnie will attend up to a total of three meetings with
stake-holders (i.e., Pima County, the Town of Marana, the Town of Oro Valley, MDWID,
and FWID) for the purpose of reporting project status and study results.
P971562 - 10- October 1998
III. PROJECT BUDGET
A budget estimate has been prepared that identifies the anticipated number of work hours by
task and associated labor costs for Malcolm Pirnie to complete the Ina Road WPCF
Reclaimed Water Distribution System project. Contract terms used to prepare this estimate
are based on Appendix B in the contract for "Miscellaneous Engineering Design Services"
(MEDS), Contract No. 16-03-124538-0498.
IV. PROJECT SCHEDULE
A Gantt chart project schedule reflecting anticipated project progress is included in this
section. The schedule identifies the sequence and expected duration of each project task and
subtask and reflects an anticipated project completion of four months after receipt of notice-
to-proceed.
The interdependence of each task is a crucial element of the schedule. Each successive task
relies on information gathered and formulated in preceding tasks. Maintaining the project
schedule will, therefore, rely heavily on frequent and timely communication between all
parties and prompt comments on information presented in technical project meetings. The
schedule assumes a one-week period from each technical project meeting to provide
comments on completed tasks for use in performing ensuing tasks.
To ensure that the schedule is maintained, schedule status will be presented and discussed at
each technical project meeting. When encountered, schedule-related problems will be
identified promptly and brought to PCWMD's attention with a recommended plan of action.
P971562 - 11 - October 1998
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INA ROAD WPCF RECLAIMED WATER
DISTRIBUTION SYSTEM FEASIBILITY STUDY
EXECUTIVE SUMMARY
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Project No. 1094-079
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DEPARTMENT
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INA ROAD WPCF RECLAIMED WATER DISTRIBUTION SYSTEM
FEASIBILITY STUDY
PIMA COUNTY WASTEWATER MANAGEMENT DEPARTMENT
April 1999
DRAFT
MALCOLM PIRNIE, INC.
One South Church Avenue, Suite 540
Tucson, Arizona 85701
1094-079
EXECUTIVE SUMMARY
Introduction
The Ina Road WPCF Reclaimed Water Distribution System Feasibility Study is being
conducted to provide information concerning the physical and economic viability of
designing, constructing, operating and administering a reclaimed water distribution system
based at the Ina Road Water Pollution Control Facility (WPCF), nerving areas northwest of
the Tucson Metropolitan area. In November 1998, Pima County Wastewater Management
Department (PCWvtD) retained Malcolm Pirnie to conduct the feasibility study over a
three-month timeframe. Malcolm Pirnie is conducting the feasibility study in close
coordination with PCW\'ID staff and with input from management staff of the Town of Oro
Valley, the Town of Marana, the Metropolitan Domestic Water Improvement District, and
the Cortaro-Marana Irrigation District. Preliminary results to date, from the Ina Road WPCF
Reclaimed Water Distribution System Feasibility Study, indicate that the unit cost for
delivery of reclaimed water from the Ina Road WPCF could range from approximately$313
per acre-foot(AF) to $427/AF assuming an annual delivery volume of 16,000 AF, a 15-year
bond repayment period at 4 percent interest, a 30-year economic life, interruptible power rate
of$0.0525 per kilowatt-hour, and effluent purchase costs ranging from$34/AF to $129/AF.
Other scenarios have been evaluated that indicate unit costs for reclaimed water may be
reduced assuming lower power costs or increased delivery volumes. For example, assuming
use of Arizona Preference Power at $0.035er kilowatt-hour, cost savings from$17/AF to
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$22/AF could be realized. Based on these preliminary results, a new reclaimed water
distribution system, based at the Ina Road WPCF, is technically and economically feasible.
The feasibility study summarized herein included the following tasks: a definition of
the project study area; an evaluation of existing and future reclaimed water demand in the
study area;route studies for distribution pipelines along the Rillito Creek, the Canada del Oro
(CDO), and the Santa Cruz River; evaluations of treatment and storage facilities required to
deliver reclaimed water for either reuse or recharge; conceptual layout designs for reclaimed
1094-079 1 DRAFT-April 1999
water treatment and distribution facilities; a study of the financial feasibility of constructing
and operating a reclaimed water facility based at the Ina Road WPCF; and an optimization
of the delivery scenarios and financing options.
Study Area
The project study area boundaries were developed to include the incorporated
boundaries for the Towns of Marana and Oro Valley, the Metropolitan Domestic Water
Improvement District, the Flowing Wells Irrigation District, and the Catalina State Park.
Figure 1 provides an illustration of the study area boundaries. The southeastern boundary
of the study area extends along the Rillito Creek from First Avenue to Craycroft Road.
Reclaimed Water Market Study
A market study was performed to identify potential reclaimed water users and
potential demands within the Ina Road WPCF Reclaimed Water Study Area. The total
current demand for reclaimed water in the overall Ina Road study area is estimated to be
approximately 7,100 acre-feet per year(AF/yr); excluding demands currently being served
by the Tucson Water Reclaimed Water System and the demands for turf irrigation at Arthur
Pack Golf Course. The projected peak year for direct reclaimed water demand is projected
to occur in 2020 at approximately 13,000 AF/yr. Approximately 60 percent of the total
_. existing and future reclaimed water demand in the study area is attributed to golf course turf
irrigation. School turf irrigation accounts for 15 percent of total demand, and turf irrigation
for public parks in the study area accounts for approximately 8 percent of total reclaimed
water demand.
Figure 2 provides an illustration of the relative reclaimed water demands for potential
users in the Ina Road study area. The study area is divided into three service areas based on
the central location of the Ina Road WPCF and the three major drainage channels in the
northwestern metropolitan area of Tucson: the Rillito Service Area, the CDO Service Area,
and the Santa Cruz Service Area. The peak reclaimed water demand in the Rillito Service
Area is projected to be approximately 1,200 AF/yr, with an additional 500 AF/yr projected
1094-079 2 DRAFT-April 1999
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for turf irrigation use at a future sports park near the Rillito Creek and La Cholla Boulevard.
The potential reclaimed water demand in the Rillito Service Area is dominated by a large
number of existing small-volume(<20 AF/yr)users scattered over the entire service area and
one future large-volume user near River Road and La Cholla Boulevard (future sports park).
The CDO Service Area is estimated to have approximately 6,600 AF/yr of peak demand for
reclaimed water, dominated by a small number of existing large-volume (>200 AF/yr) users.
Potential recharge projects in the CDO Service Area could account for an additional 10,000
to 15,000 AF/yr of reclaimed water demand. The Santa Cruz Service Area has little existing
reclaimed water demand; however, the future reclaimed water peak demand in this service
area is projected to be approximately 5,100 AF/yr. The future peak reclaimed water demand
in the Santa Cruz Service Area is projected to be primarily large-volume users.
Additional reclaimed water demand may be associated with municipal recharge
projects in the CDO Service Area. The Town of Oro Valley Water Company is currently
investigating an area in the vicinity of Big Wash and Honey Bee Canyon Wash for a 15,000
AF/yr recharge facility. High-quality reclaimed water(nitrate concentrations< 10 mg/1)may
provide an economically competitive source water for recharge at the Big Wash facility.
Metropolitan Domestic Water Improvement District officials have indicated an interest in
using up to 1,200 AF/yr of reclaimed water as a source for an in-channel recharge project in
the CDO Wash, near Cortaro Farms Road. The potential recharge projects in the CDO
Service Area may provide an additional market for reclaimed water that would help maintain
a low unit cost for the treatment and transport of reclaimed water. All evaluations of
reclaimed water transmission and use in the Santa Cruz Service Area include current
underground storage of effluent to meet future demands for reclaimed water.
Conceptual Designs and Capital Costs
The Ina Road yVPCFReclaimed Water Distribution System Feasibility Study includes
a pipeline route study in each of the three service areas and development of conceptual
designs for a variety of reclaimed water delivery alternatives with annual delivery volumes
ranging from 7,000 and 16,000 AF/yr. The 16,000 AF/yr volume assumes the blending of
1094-079 3 DRAFT-April 1999
14,000 AF/yr(12.5 million gallons per day) of effluent from the future BNR treatment train
blended with 2,000 AF/yr of effluent from the existing pure oxygen activated sludge
treatment train to meet a nitrate concentration of 10 mg/1 or less. Three reclaimed water
delivery scenarios were developed for the feasibility study: the CDO Alternative, the
Combined Alternative, and the Santa Cruz Alternative. The CDO Alternative and the
Combined Alternative provide plans to transport reclaimed water from the Ina Road WPCF
to potential users in the CDO Service Area, the western portion of the Rillito Service Area,
and specific existing users in the Santa Cruz Service Area. The Santa Cruz Alternative is
based on the construction of a gravity-flow transmission system for secondary effluent to the
lower Santa Cruz River for underground storage and recovery without distribution to
potential users. The Santa Cruz Alternative was the least expensive alternative for
developing a reclaimed water source based at the Ina Road WPCF. The alternative does not
include the costs for distribution to customers and is not included in the financial evaluation.
Figures 3 and 4 provide facility plans for the CDO Alternative and the Combined
Alternative,respectively. The CDO Alternative delivers almost the entire available amount
of reclaimed water from the Ina Road WPCF to the CDO and Rillito Service Areas. The
Rillito Service Area is truncated at La Canada Road, not Craycroft Road as considered early
in the investigation. The 16,000 AF/yr reclaimed water delivery volume exceeds the
combined reclaimed water demand of 6,820 AF/yr in the CDO and Rillito Service Areas.
Volumes of reclaimed water in excess of demand(approximately 9,000 AF/yr) delivered to
the CDO Service Area are assumed to be delivered to the proposed Big Wash Recharge
Project(Town of Oro Valley) under this alternative. The Combined Alternative facilitates
the delivery of large volumes of water to all three service areas. The reclaimed water
enhancement facilities, pump stations, storage reservoirs, and pipelines for the CDO and
Rillito Service Areas are the same for both alternatives. The Combined Alternative includes
a complete gravity flow pipeline from the Ina Road WPCF to the lower Santa Cruz River for
the purpose of delivering effluent to underground storage and recovery as well as soil aquifer
treatment facilities.
1094-079 4 DRAFT-April 1999
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approximately$52 million and$64 million,respectively. Table 1 provides a breakdown of
the components for the capital cost opinions for each of the CDO,Combined, and Santa Cruz
Alternatives. Figure 5 provides an illustration of the three service areas, the transmission
systems with the costs for individual components, the total service area costs, and maximum
capacities.
TABLE 1
BREAKDOWN OF CAPITAL COST OPINIONS FOR THE INA ROAD WPCF
RE CLAI_ IED WATER DISTRIBUTION SYSTEM ($ MILLION)
CDO Combined
Component Alternative Alternative
_ T
Pipelines
CDO Service Area $18.8 $18.8
Rillito Service Area $2.1 $2.1
Santa Cruz Service Area $1.9 $9.9
Subtotal $22.8 $30.8
Zziap
Stations $14.6 $14.0
Reservoirs $5.0 $5.0
Filtration, Flocculation, and
$9.5 $9.5
Disinfection Facilities
Recharge Facilities $0.0 $4.1
Total $51.9 L $63.9
Economic Evaluation
An evaluation of the 30-year economic unit capital costs was performed to determine
potential unit costs (S/AF) for reclaimed water from the Ina Road WPCF. The 30-year
period was selected as a representation of the average service life for system components.
To estimate the total potential unit cost for reclaimed water, the "purchase costs" for the
wastewater effluent owned by others was included in the analysis. The potential value of the
effluent was estimated by recent sales of properties with water rights, recent sales of other
types of water rights in Arizona, and using the 1999 Rate Schedule for Central Arizona
1094-079 5 DRAFT-April 1999
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e approaches, the value (potential cost) of effluent is assumed
Pro ect water. Based on thes pp
to range from $34/AF to $129/AF.
The 30-year economicp unit capital costs were calculated for the CDO Alternative and
the Combined Alternativeassuming
15-year bond repayment terms at 4.0 percent interest,
with the total amount paidequally distributed e uall over 30 years. The total volume of reclaimed
water delivered for each alternative was assumed to be 16,000 AF/year. Operations and
maintenance costs were estimated assuming an interruptible power rate of $0.0525 per
kilowatt-hour (kWh) and 9 percent tax.
Table 2 summarizes the results for estimated reclaimed water costs based on the 30-
year economic evaluation.
Estimates of reclaimed water unit costs for the CDO Alternative
ranged from $313/AF to $4 8/AF depending upon effluent purchase costs. The estimated
0 p � p
unit cost range for reclaimed water for the Combined Alternative ranged from $332/AF to
n, construction, and annual O&M cost forg
unit costs include design,$427/AF. The estimated �
y
the reclaimed water system based at the Ina Road WPCF, as well as the estimated effluent
purchase price.
TABLE 2
ESTIMATED TOTAL COSTS OF RECLAIMED WATER FOR THE CDO
AND COMBINED ALTERNATIVES ASSUMING 30-YEAR ECONOMIC
CAPITAL
REPAYMENT COSTS AND PURCHASED EFFLUENT COSTS
CDO Alternative ombinedAl .ernative-,
•
Annual Capital Repayment Cost' $4,660,000 $5,700,000
2
Annual Economic Cost(over 30 years)2 $2,330,000 $2,850,000
Unit Economic Cost ($/AF)
3 $146 $178
Unit O&M Cost ($/AF)
4 $133 $120
Wastewater
Effluent Cost S34/AF - $129/AF $34/AF - $129/AF
11.4Sa- • •••'� We - •
1 Annual Capital Repayment Cost for CDO Alternative Based on 15-year Bond Term at 4%Interest.
2-Economic Cost Based on Capital Depreciation Over 30 Years.
3 -Unit Economic Cost Assumes 16,000 AF of Reclaimed Water Delivered Annually.
4-O&M Cost Assumes Interruptible Rate of$0.0525 per kWh,9%tax,a Maximum of 18 Million kWh for the CDO
Alternative,and 13 Million kWh for the Combined Alternative.
1094-079 6 DRAFT- April 1999
A sensitivity analysis was performed on the O&M power cost assumption to
determine the potential effect of the lower power costs on the unit cost for reclaimed water
.
for each of the alternatives. If lower power costs are available, such as a State Preference
Power Rate, then the potential range of unit costs for reclaimed water would be reduced.
Table 3 provides a summary of the 30-year economic analysis assuming that a unit power
rate of$0.03 5/kWh could be obtained.
TABLE 3
30-YEAR ECONOMIC EVALUATION OF THE CDO AND COMBINED
ALTERNATIVES ASSUMING STATE-PREFERRED POWER RATE OF $0.035
PER KILOWATT-HOUR
CDO �Iternative Combined A ternative ,
Annual Capital Repayment Cost' 54.660.000 55,700,000
Annual Economic Cost (over 30 years)' 52.330,000 52,850,000
Unit Economic Cost (5/AF)3 $146 S178
Unit O&M Cost ($/AF14 $111 I $103
Wastewater Effluent Cost $34/AF - $129/AF 534/AF - $129/AF
Range of Reclaimed Water Cost S291/AF - S.386/ $315/AF - $410/AF
-Annual Capital Repayment Cost for CDO Alternative Based on 15-year Bond Term at 4%Interest.
2-Economic Cost Based on Capital Depreciation Over 30 Years.
3 -Unit Economic Cost Assumes 16,000 AF of Reclaimed Water Delivered Annually.
4-O&M Cost Assumes Preference Power Rate of$0.035 per kWh,a Maximum of 18 Million kWh for the CDO
Alternative,and 13 Million kWh for the Combined Alternative.
The unit costs for the CDO Alternative would range from$291/AF to $3 86/AF depending
upon the effluent purchase cost. Using the same assumptions,the range of unit costs for the
Combined Alternative is from $315/AF to $410/AF.
Maximum Capacity Evaluation
An additional analysis was performed to determine the maximum capacity of the
conceptual design for the reclaimed water transmission system of the Combined Alternative.
The evaluations of pipeline and pump station hydraulics indicated that the maximum
capacity of the distribution system conceptually developed for the Combined Alternative can
deliver up to approximately 23,100 AF/yr of reclaimed water to the Ina Road Study Area.
1094-079 7 DRAFT-April 1999
An economic evaluation has not been performed for the Combined Alternative assuming the
maximum delivery of reclaimed water, because the unit costs developed as part of this
feasibility study do not include all potential costs associated with the annual delivery of
23,100 AF of reclaimed water.
The potential unit costs associated with the annual delivery of 23,100 AF of
reclaimed water from the expanded Ina Road WPCF would require additional treatment
costs. To achieve the nitrate standard of 10 mg/l, a maximum volume of 16,000 AF/yr of
reclaimed water can be produced by blending effluent from the new BNR treatment train
with effluent from the existing pure oxygen activated sludge treatment train. Any additional
reclaimed water from the existing treatment train at the Ina Road WPCF in excess of 16,000
AF/yr would require nitrogen removal. Additional analysis will be required to determine the
potential treatment costs associated with denitrifying 7,100 AF/yr of effluent from the pure
oxygen activated sludge treatment train at the Ina Road WPCF.
1094-079 8 DRAFT-April 1999
INA ROAD WPCF RECLAIMED WATER DISTRIBUTION SYSTEM
FEASIBILITY STUDY
Summary and Conclusions
Based on available information, assumptions, conceptualizations, hydraulic
analyses, economic factors, and resultant findings, the following conclusions have
been reached:
■ A new Ina Road WPCF-based reclaimed water distribution system is
technically and economically viable.
■ 30-year economic unit costs, including the purchase cost of wastewater
effluent, could range from $313/AF to $427/AF based on a 15-year
bond repayment term at 4 percent interest, an interruptible power rate
of $0.0525/kWh, delivery of 16,000 AF/year, and effluent value
ranging from X34/AF to $129/AF.
■ Assuming a State Preference Power unit cost of$0.035/kWh, for the
Combined Alternative at an annual delivery of 16,000 AF, the savings
in unit cost of reclaimed water would be $17/AF. The resultant range
of reclaimed water cost for this scenario would be $315 to $410/AF.
■ The maximum annual reclaimed water delivery capacity for the
Combined Alternative is approximately 23,100 AF. Maximum
capacities for the distribution systems for each of the service areas are
approximately 14,700 AF/yr for the CDO Service Area,2,800 AF/yr for
the Rillito Service Area, and 5,600 AF/yr for the Santa Cruz Service
Area.
■ The CDO Service Area appears to have the most existing and potential
reclaimed water demand.
■ The Santa Cruz Service Area can receive reclaimed water by gravity
and, as demand grows,provides opportunity to reduce unit costs for the
whole study area. The distribution system for the Santa Cruz Service
1094-079 9 DRAFT-April 1999
k ..
•
Area could be pressurized to increase the delivery capacity to this
s ervi c e area.
■ Unit cost evaluations indicate that it is not economically viable to
extend the Rillito corridor delivery system upgradient (easterly) of La
Canada Road.
■ The most cost-effective source combination maximizes the utilization
of the effluent from the new BNR process train (14,000 acre-feet per
year) blended with a portion of the existing Pure Oxygen Activated
Sludge effluent (2,000 acre-feet per year).
■ Achievement of proposed water quality standards for effluent end uses
through enhancement of the Ina Road WPCF is technically and
economically viable. Significant treatment cost savings could result
through successful Soil Aquifer Treatment and associated recharge and
recovery.
1094-079 10 DRAFT-April 1999
INA ROAD WPCF FLECLAIMED WATER DISTRIBUTION SYSTEM
FEASIBILITY STUDY
Recommendations
Based on the foregoing conclusions, Malcolm Pirnie offers the following
recommendations for consideration by Pima County:
■ PCWMD should continue to evaluate additional optimization
opportunities to further reduce total and unit costs.
■ PCWMD should partner with stakeholders to determine the potential
use of reclaimed water in constructed recharge projects to maximize the
total demand for reclaimed water within the study area.
■ Siting studies should be undertaken to identify potential locations for
recharge and Soil Aquifer Treatment near the Ina Road WPCF.
■ PCWMD should investigate the use and potential impacts of
interruptible power rates for the proposed facilities. Other potential
sources of power (for example, State Preference Power) for all or
portions of the proposed delivery system should be identified and
evaluated.
■ PCWMD should investigate potential treatment costs associated with
nitrogen removal for effluent from the pure oxygen activated sludge
treatment train to determine total unit cost for delivery of the maximum
capacity of the proposed reclaimed water system.
1094-079 11 DRAFT-April 1999