HomeMy WebLinkAboutAgenda Report - July 20, 2016 C-10TM
CITY OF LODI
COUNCIL COMMUNICATION
AGENDA ITEM
C-io
AGENDA TITLE: Adopt Resolution Authorizing City Manager to Execute Task Order No. 28 with
Langan Treadwell Rollo, of San Francisco, for Engineering Services for Preparing
a Preliminary Water Balance Evaluation ($31,100)
MEETING DATE: July 20, 2016
PREPARED BY: Public Works Director
RECOMMENDED ACTION: Adopt resolution authorizing City Manager to execute Task Order
No. 28 with Langan Treadwell Rollo, of San Francisco, for
engineering services for preparing a preliminary water balance
evaluation, in the amount of $31,100.
BACKGROUND INFORMATION: In January 2016, City Council elected to form a Groundwater
Sustainability Agency (GSA) as defined in the 2014 Sustainable
Groundwater Management Act (SGMA). Through its membership in
the Eastern San Joaquin County Groundwater Banking Authority (GBA), Lodi has been actively working
with San Joaquin County and other agencies located within the North San Joaquin Groundwater Basin
(Basin) towards complying with SGMA requirements.
Agencies within the Basin have until June 30, 2017 to either form independent GSA's, or join a GSA
being formed by San Joaquin County that overlies the county boundary excepting those areas that intend
to form independent GSA's. SGMA also requires that high- and medium -priority groundwater basins be
managed under a Groundwater Sustainability Plan (GSP) by January 31, 2020. The GSP is intended to
become the guidance document to sustainably manage groundwater within the Basin. Currently within
the GBA membership, there is general agreement that all GSA's formed within the Basin would be
managed by one, basin -wide, GSP.
Langan Treadwell Rollo was commissioned in 2004 to assist the City in remediating tetrachloroethene
(PCE) and/or trichloroethene (TCE) groundwater contamination plumes. These chemicals were
prominently used in the dry cleaning and printing industries. The multi-year remediation effort eventually
included development of a comprehensive groundwater flow and contaminant transport computer model
that has been used to effectively determine the action needed to contain and treat the groundwater
contamination.
Prior to developing the model, Langan Treadwell Rollo estimated the potential safe yield of the aquifer
underlying the City of Lodi. Safe yield is defined as that amount of groundwater the City may extract
without further decline in groundwater elevations. The 2006 evaluation estimated the City's safe yield
between 14,600 acre-feet per year (afy) and 15,800 afy. A safe yield of 15,000 afy has been utilized for
purposes of groundwater planning, and is the safe yield identified in the City's 2010 and 2015 Urban
Water Management Plan updates.
APPROVED: Irj'Air�1�t
ephen c It+ _ • . er, City Manager
K:\WP\COUNCIL\2016\CC Langan TO 28.doc 7/7/16
Adopt Resolution Authorizing City Manager to Execute Task Order No 28 with Langan Treadwell Rollo, of San Francisco, for Engineering Services for Preparing a
Preliminary Water Balance Evaluation ($31,100)
July 6, 2016
Page 2
If approved, Langan Treadwell Rollo will develop a preliminary water balance evaluation for the City
utilizing a modified version of the groundwater contaminant transport model referenced above. The
results are expected to validate the 2006 estimated safe yield calculations, and provide better
understanding of the groundwater aquifer as it is influenced by the City's water management practices,
and by the water management practices being implemented in the outlying boundaries that include
Woodbridge Irrigation District and North San Joaquin Water Conservation District. This information will
further substantiate the City's groundwater sustainability and be critical in establishing the City's role as a
GSA when the basin -wide GSP is being prepared under the collective direction of the GBA.
FISCAL IMPACT: The costs associated with this work have been included in the Fiscal Year
2016/17 Water Operating Fund.
FUNDING AVAILABLE: Water Operating Fund ($31,100)
JordaP Ayers
Deputy City Manager/Internal Services Director
C'k QSR,Q
Charles E. Swimley, Jr.
Public Works Director
Prepared by Andrew Richie, Water Plant Superintendent
CES/ASR/tdb
Attachment
K:\WP\COUNCIL\2016\CC Langan TO 28.doc 7/7/16
LANGAN TREADWELL ROLLO
31 March 2016
Mr. Charles Swimley
Director - City of Lodi Public Works Department
P.O. Box 3006
Lodi, California 95241-1910
Subject: Proposed Scope of Work for Estimating Preliminary Water Budget
Task Order No. 28
City of Lodi, California
Dear Mr. Swimley
Technical Excellence
Practical Experience
Client Responsiveness
As requested by the City of Lodi (City) during our 21 March 2016 meeting, Langan Treadwell
Rollo (Langan) has prepared the following Scope of Work (SOW) to estimate the Preliminary
Water Budget for the City. It is our understanding that the City has formed a groundwater
sustainability agency (GSA) as defined in the 2014 Sustainable Groundwater Management Act
(SGMA). The City GSA would allow the City to develop strategies to manage their own
groundwater including gathering groundwater data, monitoring water usage, regulating wells,
and imposing water usage fines, among other duties. The City GSA shares a sizable border
along western Lodi with the Woodbridge Irrigation District (WID), with some overlap to the
west of Lower Sacramento Road. Both the City of Lodi and WID have already committed to
adjusting any shared boundaries as needed. Additionally, the City also overlaps the North San
Joaquin Water Conservation District (NSJWCD) GSA.
SCOPE OF WORK
The objective of our SOW is to assist the City in estimating the preliminary Water Budget.
Langan proposes to use the existing Lodi groundwater flow model (Model) to develop initial
estimates of flow within the City boundaries. The Model, in its current state, comprises
approximately 25% of the WID and approximately 30% of the NSJWCD areas within its model
domain. Additionally, the Model simulates conditions up to 2012 for the area outside the City
of Lodi boundaries. Currently, Langan is involved in estimating the preliminary Water Budget
for the WID, including the estimated pumping from the land in the WID that is not controlled by
the WID (non-WID land). Langan proposes the following tasks for meeting the stated
objectives.
Task 1 — Data Compilation & Evaluation
As part of our evaluation, per the City's request, Langan proposes to collect data related to
groundwater pumping and monitoring wells within the Model boundaries. The monitoring and
groundwater pumping data will permit Langan to estimate the preliminary water budget for the
City as well as help us understand the impact of recharge from WID and pumping from
NSJWCD. As part of this Task, Langan will collect the following data:
• Supply, monitoring, and extraction well lithologic and geophysical logs and associated well
construction details from the California Department of Water Resources (DWR) for the
NSJWCD areas;
3320 Data Drive, Suite 350 Rancho Cordova, CA 95670 T: 916.476.6790 F: 916.476.6792 www.langan.com
California • New Jersey • New York • Connecticut • Pennsylvania • Ohio • Washington, DC • Virginia • Florida • Texas • North Dakota • Abu Dhabi • Athens • Doha • Dubai • Istanbul
Proposed Scope of Work for Estimating Preliminary Water Budget
Task Order No. 28
City of Lodi, California
Lagnan Project: 730392338
31 March 2016
Page 2 of 4
• Historical groundwater level data for California Statewide Groundwater Elevation
Monitoring (CASGEM) wells located within the NSJWCD boundaries within the model
domain ;
• Land use data from WID, NSJWCD, and San Joaquin County for the areas within the WID
and NSJWCD GSAs; and,
• Extraction data from City of Lodi supply wells.
Following the data compilation, Langan will evaluate the data and identify water use data gaps,
if any, regarding the data. The existing data will then be used to develop a conceptual model to
calculate the water budget within the City boundaries, as well as determine the impact of
pumping from agricultural areas that lie outside the City coverage area and in the WID and
NSJWCD areas.
Task 2 — Estimate Safe Yield
Langan will estimate the current safe yield for the City, specifically related to changes, if any,
due to the recent drought conditions, and compare it to the safe yield assessment that was
previously prepared for the City in 2007.
Task 3 — Modify the Model
As requested by the City, Langan has included this task outlining recommended modifications
to the existing Model. In 2015, Langan had modified the Model by simulating the impacts of
the current drought (2012 to 2015) on the groundwater flow and plume migration beneath the
City of Lodi. As part of our modification Langan had performed the following tasks —
1. Modified the existing Model by applying 2012 to 2015 City well pumping to evaluate the
impact of the drought;
2. Did not modify Ag well pumping for the drought years. The Ag well pumping simulated
for the drought years was based on the Ag extraction rates assumed for the years prior
to the drought; and,
3. Assumed 2015 City well pumping (30% decrease in City pumping) for years 2016 to
2025
Results of that modeling effort indicated the following:
a. Decreasing trend in groundwater levels in 2014 to 2015 (increasing trend observed in
years 2012 to 2014) indicating that the drought was having an impact on the
groundwater resources beneath the City
b. Decreasing capture zones of the Lodi extraction wells due to a decrease in the pumping
rates of the Lodi wells
c. Impact of Ag well pumping in drought years was observed to be significant based on
the following results from the model —
LANGAN TREADWELL ROLLO
Proposed Scope of Work for Estimating Preliminary Water Budget
Task Order No. 28
City of Lodi, California
Lagnan Project: 730392338
31 March 2016
Page 3 of 4
Difference in simulated and observed ground water levels in 2009 was between
0 to 6 feet when Ag wells were simulated
�i. Difference in simulated and observed ground water levels in 2014 (drought year)
was between 5 to 15 feet. This is because Ag wells have not been simulated
with their revised rates for the drought years.
We have previously observed that Ag well pumping has a significant impact on groundwater
levels and contaminant plume migration. The severe drought from 2011 to 2015 has resulted
in a significant drop in groundwater levels within the NSJWCD areas. This may have resulted in
some of the current Ag wells going dry, leading to the completion of deeper Ag wells within
the WID and NSJWCD areas. Also, changes in land use patterns from open pastures to cash
crops (like walnuts) that use significantly more water has created conditions where a decrease
in pumping by the City and an increase in pumping from the NSJWCD Ag wells would possibly
impact the migration of both the PCE and DBCP plumes within the City limits. We propose to
update the Ag well pumping from outside the City limits by applying the most recent land use
patterns within the WID and the NSJWCD areas along with any new Ag wells that may have
been installed since 2011. These changes in the model will provide a more accurate
understanding of groundwater flow, and subsequently contaminant plume migration, beneath
the City. Additionally, the modified model would be used to estimate the impact of both
recharge activities in the WID areas and the pumping activities in the NSJWCD areas on the
overall water budget for the City of Lodi.
Task 4 — Preliminary Water Budget
Following completion of Tasks 1 through 3, Langan will develop a preliminary water budget for
the City using the existing Model. The water budget will provide preliminary estimates of the
total groundwater recharge within the WID, the inflow to and outflow from the WID, City and
NSJWCD boundaries, and preliminary impacts of pumping from the non-WID land within the
WID boundaries and the NSJWCD areas. Langan proposes to use input from our work
currently being performed for the WID preliminary water budget. Our results will be presented
in a technical memorandum summarizing the methodology applied to estimate and check the
preliminary water budget. Additionally, if requested, we will prepare a graphical representation
of the water budget for presentation purposes.
Task 5 — Meeting
Following completion of the above activities, Langan will meet with the City staff to discuss
and present the safe yield assessment, the completed preliminary water budget results, and
the results obtained from the model modification.
FEE ESTIMATE
We propose to perform the work on a time -and -expense basis in accordance with terms of the
City of Lodi Professional Services Agreement. We have estimated the following costs for
Tasks 1 through 5. Additionally, the costs of this Scope of Work will not exceed an amount of
$31,100 without your prior authorization.
LANGAN TREAOWELL ROLLO
Proposed Scope of Work for Estimating Preliminary Water Budget
Task Order No. 28
City of Lodi, California
Lagnan Project: 730392338
31 March 2016
Page 4 of 4
TASK
FEE
Task 1 — Data Compilation & Evaluation
$6,800
Task 2 — Safe Yield Assessment
$2,300
Task 3 — Model Modification
$11,000
Task 4 — Preliminary Water Budget
$8,600
Task 5 — Meeting
$2,400
TOTAL
$31,100
Our fee is based on obtaining the following:
1. Most recent well log data from the Department of Water Resources (DWR); and,
2. Land use data of the WID and NSJWCD customers.
SCHEDULE
Our services can begin immediately upon receiving your written authorization. We anticipate
requiring four weeks to complete the project.
In summary, Langan proposes to provide a preliminary water budget for the City of Lodi GSA
using current monitoring data, the modified City of Lodi model, land use and pumping data from
WID and NSJWCD areas, and the current pumping from the City wells. We look forward to
assisting you on this project. If you have any questions, please do not hesitate to call Varinder
Oberoi at (415) 424-3009 or Mr. Philip Smith at (415) 955-5249.
Sincerely yours,
Langan Treadwell Rollo
Varinder Oberoi, PE #C69037 Philip G. Smith, CPGS
Senior Project Manager Managing Principal
Stephen Schwabauer
City Manager
Janice D. Mag c ich
City Attorney
Jennifer Ferraiolo Date
City Clerk
730392339.01 VO_Proposal
LANGAN TREADWELL ROLLO
RESOLUTION NO. 2016-136
A RESOLUTION OF THE LODI CITY COUNCIL
AUTHORIZING THE CITY MANAGER TO EXECUTE
TASK ORDER NO. 28 WITH LANGAN TREADWELL
ROLLO, OF SAN FRANCISCO, FOR ENGINEERING
SERVICES FOR PREPARING A PRELIMINARY
WATER BALANCE EVALUATION
WHEREAS, in January 2016, City Council elected to form a Groundwater Sustainability
Agency (GSA) as defined in the 2014 Sustainable Groundwater Management Act (SGMA); and
WHEREAS, through its membership in the Eastern San Joaquin County Groundwater
Banking Authority (GBA), Lodi has been actively working with San Joaquin County and other
agencies located within the North San Joaquin Groundwater Basin (Basin) towards complying
with SGMA requirements; and
WHEREAS, results are expected to validate the 2006 estimated safe yield calculations,
and provide better understanding of the overall groundwater aquifer as it is influenced by the
City's water management practices, and by the water management practices being
implemented in the outlying boundaries that include Woodbridge Irrigation District and North
San Joaquin Water Conservation District; and
WHEREAS, staff recommends authorizing the City Manager to execute Task Order
No. 28 with Langan Treadwell Rollo, of San Francisco, for engineering services for preparing a
preliminary water balance evaluation, in an amount not to exceed $31,100.
NOW, THEREFORE, BE IT RESOLVED that the Lodi City Council does hereby
authorize the City Manager to execute Task Order No. 28 with Langan Treadwell Rollo, of
San Francisco, California, for engineering services for preparing a preliminary water balance
evaluation, in an amount not to exceed $31,100.
Dated: July 20, 2016
I hereby certify that Resolution No. 2016-136 was passed and adopted by the City
Council of the City of Lodi in a regular meeting held July 20, 2016, by the following vote:
AYES: COUNCIL MEMBERS — Johnson, Kuehne, Mounce, and Mayor Chandler
NOES: COUNCIL MEMBERS — None
ABSENT: COUNCIL MEMBERS — Nakanishi
ABSTAIN: COUNCIL MEMBERS — None
4 . NIFER FERRAIOLO
City Clerk
2016-136