MONITORING WELL CONSTRUCTION PROJECT

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Groundwater Monitoring Well in the Aromas & Purisima Formations (Component 10)

Proposition 50

State Water Resources Control Board

Integrated Regional Water Management Implementation Grant

Northern Santa Cruz County Integrated Regional Water Management Plan Agreement No. 07-507-550-0, as amended 07-507-550-2

May 2011

Prepared by:

Soquel Creek Water District

Regional Water Management Foundation

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- i - Grant Agreement No.: 07-507-550-0

Grant Agency: California State Water Resources Control Board Grant Program: Integrated Regional Water Management Program Total Grant Award: $12,500,000

Grantee: Regional Water Management Foundation Agreement Period: July 1, 2007 – May 1, 2011

Component Project No.:10

Component Title: Groundwater Monitoring Well in the Aromas & Purisima Formation Subgrantee/Component Lead: Soquel Creek Water District

Component Grant Award: $144,439 Matching Funds Total: $537,384 Watershed: Aptos

Project Type: Monitoring Well Construction

Funding for this project has been provided in full or in part through an agreement with the State Water Resources Control Board. The contents of this document do not necessarily reflect the views and policies of the State Water Resources Control Board, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. (Gov. Code, § 7550; 40 CFR 31.20)

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- ii - GRANT SUMMARY

Completed Grant Summaries are made available to the public on the State Water Resources Control Board’s (SWRCB) website at http://www.waterboards.ca.gov/funding/grantinfo.html

Date filled out: 6/17/2008; updated 5/30/2011

Grant Information: Please use complete phrases/sentences. Fields will expand as you type.

1. Grant Agreement Number: 07-507-550-0

2. Project Title: NORTHERN SANTA CRUZ COUNTY INTEGRATED REGIONAL WATER MANAGEMENT PLAN - Groundwater Monitoring Wells in the Aromas & Purisima Formation (Component 10)

3. Project Purpose – Problem Being Addressed: The Soquel Creek Water District (SqCWD) will install a new dedicated groundwater monitoring well cluster located at the County of Santa Cruz Polo Grounds Park to monitor inland groundwater levels and quality. Data from these wells will expand the existing monitoring network and improve the ability to evaluate the impacts of local pumping on shallow water levels and improve understanding of the

hydrologic connection between the Aromas and Purisima aquifers. The wells will be screened at three (3) different levels. This groundwater data will benefit the SqCWD, Central Water District, County of Santa Cruz, and private well operators in the vicinity by filling data gaps in the existing monitoring network and enabling more informed decision making. Benefits of this project include providing the ability to manage an expanded area of the groundwater basin that is not currently well understood, assessing the potential impacts of local pumping on surface water flows, and promoting collaboration among regional water management agencies.

4. Project Goals

a. Short-term Goals: Short term goals are to: 1) identify the optimal location and screening depths for the monitoring wells in the Polo Grounds Park; 2) Complete the design and construction specifications for the monitoring well cluster; 3) Construct the monitoring wells; 4) Incorporate the monitoring wells into the existing data collection program.

b. Long-term Goals: Long term goals include the continued use of the groundwater quality and level monitoring data to augment the existing network of monitoring wells. The monitoring data will document conditions over time, detect changes in water levels and quality, and better enable Soquel Creek Water District and other local water agencies to manage water resources.

5. Project Location: (lat/longs, watershed, etc.) Aptos Watershed

a. Physical Size of Project: (miles, acres, sq. ft., etc.) Work area < 1 ac.

b. Counties Included in the Project: Santa Cruz

c. Legislative Districts: (Assembly and Senate) Assembly 27 and Senate 15 6. Which SWRCB program is funding this grant? Please “X” box that applies.

Prop 13 Prop 40 Prop 50 EPA 319(h) Other

Grant Contact: Refers to Grant Project Director.

Name: 1. Christina Cuevas 2. Laura Brown

Job Title: 1. Grant Project Director 2. SqCWD General Manager Organization: 1. Regional Water Management Foundation

2. Soquel Creek Water District

Webpage Address:1. www.cfscc.org/RWMF 2. http://www.soquelcreekwater.org

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Address:1. 7807 Soquel Drive, Aptos, CA 95003

2. 5180 Soquel Drive, Soquel, CA 95073 (P.O. Box 1550, Capitola, CA 95010)

Phone:1. 831-662-2000 2. 831-475-8500 Fax: 1. 831-477-0991 2. 831-475-4291 E-mail: 1. christina@cfscc.org 2. LauraB@soquelcreekwater.org

Grant Time Frame: Refers to the implementation period of the grant.

From: 7/1/2007 To: 3/31/2011

Project Partner Information: Name all agencies/groups involved with project. Soquel Creek Water District, Regional Water Management Foundation

Nutrient and Sediment Load Reduction Projection: (If applicable) N/A

Please provide a hard copy to your Grant Manager and an electronic copy to your Program Analyst for SWRCB website posting. All applicable fields are mandatory. Incomplete forms will be returned.

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- i - TABLE OF CONTENTS

EXECUTIVE SUMMARY ... 1 

PROBLEM STATEMENT & RELEVANT ISSUES ... 2 

PROJECT GOALS ... 5 

PROJECT DESCRIPTION ... 5 

PUBLIC OUTREACH ... 12 

CONCLUSIONS ... 13 

APPENDIX A ‐ REFERENCES  APPENDIX B ‐ LIST OF DELIVERABLES  APPENDIX C ‐ LIST OF SUBCONTRACTORS  APPENDIX D – WELL COMPLETION REPORT  APPENDIX E ‐ WATER QUALITY DATA  APPENDIX F – TECHNICAL MEMORANDUM DATA LOGGER INSTALLATION AND SUMMARY DATA  APPENDIX G ‐ AQUIFER TEST ANALYSIS  LIST OF FIGURES Figure 1: Locations of Existing and New Wells ... 4 

Figure 2: Polo Grounds Park and Well Location ... 7 

Figure 3: Polo Grounds Construction Schematic (no vertical exageration) ... 8 

Figure 4: Cross-Section Line Location ... 9 

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Executive Summary

Component 10 of the Northern Santa Cruz County Integrated Regional Water Management Plan involved installing a cluster of three monitoring wells in Santa Cruz County’s Polo Grounds Park. The location of the monitoring wells is near an irrigation well that is to be converted by Soquel Creek Water District (SqCWD) to a water supply well. The monitoring wells were installed to meet four goals:

Design and install wells capable of providing accurate groundwater elevation data.

Measure the drawdown from pumping the Polo Grounds well.

Estimate whether groundwater in local aquifers is in direct communication with Valencia Creek.

Assess if there is a sharp visible interface between the Aromas and Purisima Formations.

The total cost of the project was $681,823, with $144,439 funded by an IRWMP (Prop 50) Grant and

$537,384 coming from matching funds provided by SqCWD.

The three wells were screened at three different depths. The well depths were chosen to measure groundwater levels in the same aquifers that are screened by the Polo Grounds well, to clearly show any vertical groundwater gradients, and to assess the interaction between shallow aquifers and Valencia Creek. The three wells were screened as follows:

1. SC-20A - the deepest well screens the same horizon as the bottom screen in the nearby Polo Grounds well. It is screened from -180.6 to -200.6 feet NGVD29;

2. SC-20B - the middle well screens the same horizon as the uppermost screen in the Polo Grounds well. It is screened from 14.3 to –15.7 feet NGVD29;

3. SC-20C - the shallowest well is screened just below the elevation of nearby Valencia Creek to look for shallow groundwater interactions with the creek. It is screened from 99.3 to 79.3 feet NGVD29

The three monitoring wells have met all of the project goals and desired outcomes listed in the Project Assessment and Evaluation Plan (PAEP) that was prepared for this grant:

The monitoring wells were successfully installed as designed. The middle and lower two wells provide accurate groundwater level data for the local aquifers, as well as accurate vertical gradient data. The shallowest well provides data regarding interactions between Valencia Creek and the shallow aquifers.

The monitoring wells were used as observation wells for an aquifer test performed on the nearby Polo Grounds well. Water level transducers and data loggers were installed in each of the three monitoring wells for continuously recording groundwater levels during the aquifer test. The test successfully estimated aquifer properties.

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The shallowest monitoring well is dry, demonstrating that there is an unsaturated zone between Valencia Creek and the local aquifers. Therefore there is no direct communication between Valencia Creek and the local aquifers.

No clear interface was discernable between the Purisima Formation and the Aromas Formation.

In addition to meeting all of the goals listed in the PAEP, the three monitoring wells have been incorporated into SqCWD’s ongoing groundwater level measuring program, with the data from these wells collected and analyzed regularly by SqCWD. Funding for this ongoing monitoring and data analysis is completely provided by SqCWD revenue. These monitoring wells will continue to provide valuable information and data as SqCWD works cooperatively with other local agencies to manage and optimize local groundwater resources. The new monitoring wells will provide groundwater level data that can be used to map groundwater flow directions and demonstrate the ongoing impact from pumping the Polo Grounds well.

Problem Statement & Relevant Issues

SqCWD has an active, ongoing program to reduce the threat of seawater intrusion into the Soquel- Aptos Basin. Part of this program involves shifting groundwater pumping away from the coast. New inland wells, however, may influence streams or other sensitive habitats.

An existing irrigation well located in the Santa Cruz County Polo Grounds Park will be converted to a municipal production well by SqCWD to supply water to the local service area. This new municipal well is located in an area with limited existing municipal production. A map showing existing and planned municipal wells and dedicated monitoring wells is shown on Figure 1. The limited existing nearby municipal production is advantageous because there will be no interference with nearby wells.

However, the lack of wells in the area results in limited hydrogeologic information about this area.

The work performed under this component provided the hydrogeologic information needed to adequately assess the impacts of converting the existing Polo Grounds Park well into a municipal well. In particular, the following outstanding questions were addressed:

What are the groundwater levels in this portion of the Soquel-Aptos Basin?

How much drawdown can be expected from the municipal well?

How closely connected is the local groundwater with nearby Valencia Creek? If local

groundwater levels are near the elevation of the base of Valencia Creek, pumping may impact flows in Valencia Creek. If local groundwater levels are well below the base of Valencia Creek, then pumping will have no impact on Valencia Creek flows.

What is the interface between the Aromas and Purisima Formations? The County of Santa Cruz was interested in seeing whether a sharp contact between the two formations can be observed in the cuttings.

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A new monitoring well cluster was installed by SqCWD in the Polo Grounds Regional Park to address the issues documented above. These monitoring wells continue the inland expansion of the existing monitoring well network used by SqCWD to characterize groundwater levels and hydrology, as shown on Figure 1. As with all inland monitoring wells in SqCWD’s network, groundwater quality data are collected from the nearby municipal production wells. At this location, groundwater quality data will be collected from the Polo Grounds Well that is being retrofitted under Component 9.

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Figure 1: Locations of Existing and New Wells

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Project Goals

The goal of this project was to install a new cluster of groundwater level monitoring wells that augment the existing network of monitoring wells. This goal has been achieved. A second goal was to document groundwater level conditions over time, detect changes in water levels, and better enable SqCWD and other local water agencies to manage water resources by developing a better understanding of groundwater flow directions. This ongoing goal has been started, and monitoring of these wells will continue as part of SqCWD’s regular groundwater monitoring efforts.

The desired outcome of this project was that the new monitoring wells provide data that enables improved understanding of seasonal and annual variations in local groundwater levels and informs management decisions about the amount and location of groundwater pumping. Specific desired outcomes included the following:

Design and install wells capable of providing accurate groundwater elevation data. If there are multiple aquifers, the wells should provide groundwater elevation data that can show any vertical gradients. This outcome was achieved. Three monitoring wells were designed and installed that measure groundwater elevation data from three aquifers.

Measure the drawdown from pumping the Polo Grounds well. Use this drawdown information to estimate the hydrologic parameters in the area. This outcome was achieved. Groundwater levels were measured in the new monitoring wells during an aquifer test performed on the Polo Grounds Park well. These data were used to estimate local aquifer parameters.

Design and install the monitoring wells such that the groundwater level data can be used to estimate whether groundwater in local aquifers is in direct communication with Valencia Creek.

This outcome was achieved. The shallowest monitoring well is dry, demonstrating that there is an unsaturated zone between Valencia Creek and the local aquifers. Therefore, there is no direct communication between Valencia Creek and the local aquifers.

Acquire accurate drill cuttings to see if there is a sharp visible interface between the Aromas and Purisima Formations. This outcome was achieved. The drill cuttings showed no sharp interface between the Aromas and Purisima Formations. The fluvial deposits of the Aromas Formation appear similar to some of the shallow marine sediments of the Purisima Formation.

Project Description

Design and Install Wells Capable of Providing Accurate Groundwater Elevation Data The Soquel Creek Water District (SqCWD) installed a cluster of three new dedicated groundwater monitoring wells at the County of Santa Cruz Polo Grounds Regional Park. The wells are named SC- 20A, SC-20B, and SC-20C. The total cost and funding sources for installing the wells are shown in Table 1.

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Table 1: Component 10 Costs and Funding Sources Polo Grounds Park Monitoring Wells

Funding Source Cost

Grant Funds IRWMP (Prop 50) Grant $144,439

Matching Funds Soquel Creek Water District $537,384

Total Funds $681,823

The three wells are located between 142 and 159 feet from the Polo Grounds Well, and lie between the Polo Grounds Well and Valencia Creek (Figure 2). The depths of the three wells were chosen as follows:

The deepest well (SC-20A) screens the same geologic horizon as the bottom screen of the Polo Grounds Well. It is screened from -180.6 to -200.6 feet NGVD29;

The middle well (SC-20B) screens the same geologic horizon as the uppermost screen of the Polo Grounds Well. It is screened from 14.3 to –15.7 feet NGVD29;

The shallowest well (SC-20C) is screened just below the elevation of nearby Valencia Creek to look for shallow groundwater interactions with the creek. It is screened from 99.3 to 79.3 feet NGVD29.

The completion depths of the three monitoring wells, as well as the completion information for the Polo Grounds Well are shown on Figure 3. Figure 3 includes ground surface elevations surveyed along a cross-section line near the new monitoring wells. The surveyed location of the cross-section line is shown in Figure 4. These ground surface elevations demonstrate how the depths of the three new monitoring wells relate to the depth of nearby Valencia Creek.

A fourth monitoring well was contemplated that would be screened in the same geologic horizon as the middle screen of the Polo Grounds well. The lithology in this middle screen area was sandier, and apparently more transmissive, than the lithology corresponding to the bottom screen area. The project, however, was only funded for three wells, and it was decided that monitoring the top and bottom screens of the Polo Grounds well would show the greatest vertical gradient, fulfilling one of the desired outcomes.

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Figure 3: Polo Grounds Construction Schematic (no vertical exageration)

Well Construction Drawing shown in Appendix D Well Completion Report, Plate 2

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Figure 4: Cross-Section Line Location

Polo Grounds Well Approximate Monitoring

Well Locations

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All well installation activities were overseen by California registered geologists from Pueblo Water Resources, Inc. The geologist’s oversight assured that the monitoring wells were installed in a way that provides accurate groundwater elevation data. The three monitoring wells were constructed using direct rotary drilling techniques. A geophysical survey was conducted on the deepest borehole.

Appendix D contains the lithologic log, the geophysical log, and photographs of the cutting samples.

The well casings consist of flush-threaded, Schedule 80 PVC. Well screens consist of perforated sections of casing with 0.040-inch, machine cut horizontal slots. The casings were centered in the borehole with centering guides placed immediately above and below the well screens, and at

approximate 80-feet intervals throughout the blank portions of the monitoring wells. Gravel pack for all of the wells consisted of an RMC No. 8 blend. The gravel pack was placed from the base of the well to 10 feet above the screen.

Bentonite chip transition seals were placed in the annulus on top of the gravel pack through a tremie pipe. Cement grout annular seals were installed in each of the wells. The grout consisted of 10-sack sand slurry. Bentonite was added to the mixture to slow the curing process, reduce the heat

generated during curing, and protect the integrity of the well casings. The cement grout was placed from the top of the bentonite transition seal to the surface. The seal prevents water from overlying formations or the surface from moving through the annular space between the casing and the borehole and being pumped into the well. A Santa Cruz County inspector was present to witness sealing operations for each well.

Each well was provided with a water-tight, flush-mounted, traffic-rated circular well vault set in place with concrete. The general construction features of the wells are shown on Figure 3. Complete drilling and construction details are included in the Monitoring well construction project (SC20 A, B, and C) well completion report (Pueblo Water Resources Inc., 2009).

The monitoring wells were developed by airlifting and surging. Well development removes drilling fluids from the well’s borehole, cleans fine sediment from the well, and improves the hydrologic connection between the well and the surrounding formation. This ensures that the groundwater levels and groundwater chemistries measured in the monitoring wells are representative of the surrounding aquifer. Development was performed until the discharge of each well following surges remained relatively clear. The deep and intermediate wells were sampled during the final stages of well development; the shallow well was dry and could not be sampled. Samples were analyzed for basic general mineral constituents. These water quality data were entered into Soquel Creek Water District’s groundwater quality database where they can be accessed for future groundwater quality analysis. The monitoring wells are not intended for regular water quality monitoring, however the water quality reports from the Polo Grounds production well will be made available for the County wide water quality monitoring data-base. A summary of the analytical data is presented in Table 2.

Complete analytical data are included in Appendix E.

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Table 2: Summary of Water Quality Data Polo Grounds Park Monitoring Wells

Intermediate Deep

Sample Date May 27, 2009 May 27, 2009

Specific Conductance,

µmhos/cm 516 487

TDS, mg/l 335 313

Calcium, mg/l 27 24

Magnesium, mg/l 36 34

Potassium, mg/l 2 2

Sodium, mg/l 26 23

Chloride, mg/l 25 23

Sulfate, mg/l 34 19

Bicarbonate (as HCO3), mg/l 233 243

Iron, µg/l 273 ND (< 50)

Manganese, µg/l 35 209

Nitrate (NO3), mg/l 3 ND (< 1)

ND – Not Detected

Shallow well dry – no sample collected.

Look for Sharp Interface Between Aromas and Purisima Formations

The lithologic logs and geophysical logs were reviewed for evidence of a sharp contact between the mapped overlying Aromas Formation and the underlying Purisima Formation. The geophysical logs collected during drilling included measurements of natural gamma radiation, spontaneous potential, short-and long-normal resistivities, and single point resistance. A sharp transition between the Aromas Formation and the Purisima formation may be indicated by a significant change in the lithologic descriptions, or a change in the shape of the geophysical logs. No clear demarcation between the two formations was observed. This suggests that the contact between the upper Purisima Formation and the lower Aromas Formation provides little or no hydrogeologic control. It may also suggest that the mapped contact between the Aromas Formation and Purisima Formation is incorrectly placed (Mike Cloud, County of Santa Cruz, personal communication, January, 2011).

Obtain Groundwater Level Information, and Assess Local Aquifer Connection to Valencia Creek

Water level transducers and data loggers were installed in each of the three monitoring wells on August 27, 2009. These transducers measure groundwater levels in the monitoring wells

automatically. The data loggers were set to read water levels every 30 minutes. These groundwater level data will be downloaded every month, and included in the District’s groundwater level database.

The groundwater level data will show how groundwater fluctuates in response to pumping of the nearby Polo Grounds well, as well as recharge from Valencia Creek. A complete description of the data logger installations are documented in the Water level loggers installed in Polo Grounds monitoring wells technical memorandum (HydroMetrics LLC, 2009b). The data logger depths and pressure ranges are summarized in Appendix F.

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The shallowest monitoring well was screened just below the bottom of Valencia Creek. If water was flowing out of Valencia Creek onto a perched water table, we would expect this shallow well to show groundwater levels slightly lower than the level of Valencia Creek. If groundwater was flowing into Valencia Creek, we would expect this shallow well to show groundwater levels slightly higher than the level of Valencia Creek. The shallowest monitoring well is dry, demonstrating that there is an

unsaturated zone between Valencia Creek and the local aquifers. Therefore there is no direct communication between Valencia Creek and the local aquifers. The District will continue to monitor groundwater levels in the shallowest well. Rising groundwater levels in this well may indicate

seasonal interaction between the local aquifers and Valencia Creek.

Observe Drawdown from Pumping the Polo Grounds Well, and Estimate Hydrologic Parameters

The new monitoring wells were incorporated into an aquifer test that was conducted in May, 2009.

The aquifer test was necessary for the Component 9 portion of the IRWMP grant, and the new monitoring wells were crucial to the success of the test. Water level data from the new monitoring wells were used to estimate aquifer properties and to determine the sustainable pumping rate of the existing irrigation well. The test was run for 21.3 hours between May 28 and May 29, 2009. Water level data were collected in two monitoring wells during the test: Polo Grounds Deep MW (SC-20A) and Polo Grounds Middle MW (SC-20B). Aquifer parameters estimated from the test are shown in Table 3. A discussion of the aquifer test analysis is included in Appendix G. Complete results from the aquifer test are documented in the Polo Grounds Well Test report (HydroMetrics LLC, 2009a).

Table 3: Estimated Aquifer Properties

Parameter Calibrated Value

Vertical Resistance above Shallow Screen 190 days Transmissivity of Shallow Aquifer 177 feet2/day Transmissivity of Middle Aquifer 342 feet2/day Transmissivity of Deepest Aquifer 1,986 feet2/day

Public Outreach

Public outreach for the overall Northern Santa Cruz County IRWM Implementation grant has occurred on multiple occasions since the start of the grant. In 2008, at the kickoff of the grant, there were

outreach efforts to local newsprint media (GoodTimes, Santa Cruz Sentinel) which resulted in articles on the IRWM effort and the funded projects. A summary of the Monitoring Well, and the other

components funded by this grant, is posted on the Regional Water Management Foundation website (rwmf.org). There have been several public presentations on the local IRWM efforts and the funded projects. These include presentations in 2008 (John Ricker, Santa Cruz County) and 2009 (Chris Coburn, Santa Cruz County) at Blue Circle events. Started in 1996 by the Santa Cruz County

Resource Conservation District and Natural Resources Conservation Service, the Blue Circle provide an informal forum for local agencies, units of government, special interest groups, and concerned

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citizens to meet and exchange views on natural resource issues affecting residents living in the County’s watersheds.

Outreach to public agencies included coordination with the Santa Cruz County Environmental Health Department and Santa Cruz County Parks Department. The well siting and well design activities were both coordinated with these agencies through multiple meetings and telephone calls. These meetings ensured that the Santa Cruz County Parks Department would not be inconvenienced by the well installation; and that specific geological data of interest to the Santa Cruz County Environmental Health Department would be obtained as part of the project. In November 2008, Santa Cruz IRWM representatives (John Ricker, Santa Cruz County; Tim Carson, Regional Water Management Foundation) presented to the Central Coast Regional Water Quality Control Board on the projects funded by this grant. In November 2009, the IRWM partner agencies (including Soquel Creek WD) convened with interested local agencies to review current and future IRWM efforts.

Conclusions

Three monitoring wells were successfully installed and sampled at Polo Grounds Park in Aptos, California. These wells have provided important data, and will continue to provide additional data in the future, on a number of issues including:

1. Filling in critical gaps in the existing monitoring network

2. Improving the District’s ability to evaluate the impacts of local pumping on shallow groundwater levels.

3. Providing critical data for understanding the hydrologic connection between the Aromas and Purisima aquifers.

4. Helping assess the impacts of local pumping on surface water flows in nearby Valencia Creek.

All of the goals and desired outcomes listed in the PAEP were successfully met. The desired outcomes listed in the PAEP included:

Design and install wells capable of providing accurate groundwater elevation data. If there are multiple aquifers, the wells should provide groundwater elevation data that can show any vertical gradients. This outcome was achieved. Three monitoring wells were designed and installed that measure groundwater elevation data from three aquifers.

Measure the drawdown from pumping the Polo Grounds well. Use this drawdown information to estimate the hydrologic parameters in the area. This outcome was achieved. Groundwater levels were measured in the new monitoring wells during an aquifer test performed on the Polo Grounds Park well. These data were used to estimate hydrologic parameters.

Design and install the monitoring wells such that the groundwater level data can be used to estimate whether groundwater in local aquifers is in direct communication with Valencia Creek.

This outcome was achieved. The shallowest monitoring well is dry, demonstrating that there is an unsaturated zone between Valencia Creek and the local aquifers. Therefore there is no direct communication between Valencia Creek and the local aquifers.

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Acquire accurate drill cuttings to see if there is a sharp visible interface between the Aromas and Purisima Formations. This outcome was achieved. The drill cuttings showed no sharp interface between the Aromas and Purisima Formations.

The three monitoring wells have been incorporated into SqCWD’s ongoing groundwater level measuring program. Groundwater levels are currently being recorded every 30 minutes with

transducers and data loggers. The data from these data loggers are collected and analyzed regularly by SqCWD. Funding for this ongoing data collection and analysis program is completely provided by SqCWD revenue. These monitoring wells will continue to provide valuable information and data as SqCWD works cooperatively with other local agencies to manage and optimize local groundwater resources.

In addition to meeting the goals of the PAEP, the three targets listed in the Component 10 PAEP were fully achieved, or are currently being achieved. These three targets included:

1. Installing 100% functional monitoring wells. Three monitoring wells were installed. All three are providing important groundwater level data. Although the shallowest monitoring well is dry, it provides important data. The dry well definitively demonstrates a hydraulic separation

between Valencia Creek and the underlying aquifers. Should groundwater fill the shallow well, it will show at what times of the year Valencia Creek is in direct contact with the underlying aquifers.

2. Gathering 100% of relevant data generated at new monitoring wells to evaluate impacts of pumping new Polo Grounds production well on groundwater basin and nearby Valencia Creek.

The three new wells provided all the data necessary to estimate the impact of pumping the Polo Grounds well. Groundwater levels from the deep and middle monitoring well both visibly demonstrated the amount of expected drawdown from the Polo Grounds well, and allowed us to estimate local hydrologic parameters. The dry shallow monitoring well demonstrates how pumping the Polo Grounds well has no influence on nearby Valencia Creek.

3. Sharing 100% of relevant Polo Grounds well data with Santa Cruz County Coordinated

Monitoring Program (Component 15). This target is currently being met. All groundwater level data and groundwater quality data from the new monitoring wells have been shared with the Santa Cruz County Coordinated Monitoring Program. All future data from the Polo Grounds well will continue to be shared with the Santa Cruz County Coordinated Monitoring Program.

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Appendix A - References

Hemker, C.J. 1999a. Transient well flow in vertically heterogeneous aquifers, Journal of Hydrology, vol. 225, pp. 1-18.

Hemker, C.J. 1999b. Transient well flow in layered aquifer systems: the uniform well-face drawdown solution, Journal of Hydrology, vol. 225, pp. 19-44

HydroMetrics LLC. 2009a. Polo grounds well test, 13 p., May.

HydroMetrics LLC. 2009b. Water level loggers installed in Polo Grounds monitoring wells, technical memorandum, 2 p., September.

Pueblo Water Resources Inc. 2009. Monitoring well construction project (SC20 A, B, and C); Polo grounds park, Santa Cruz County, California; Well completion report, 4 p., June.

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Appendix B - List of Deliverables

The reports produced as part of the Polo Grounds Park monitoring well project that were funded fully or partially through IRWMP grant number 07-507-550-0 include:

HydroMetrics LLC. 2009. Water level loggers installed in Polo Grounds monitoring wells, technical memorandum, 2 p., September.

Pueblo Water Resources Inc. 2009. Monitoring well construction project (SC20 A, B, and C); Polo grounds park, Santa Cruz County, California; Well completion report, 4 p., June.

Additionally, three well completion reports were produced and submitted to DWR as required by law.

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Appendix C - List of Subcontractors

HydroMetrics LLC

519 17th Street, Suite 500 Oakland, CA 94612 (510) 903-0458

Pueblo Water Resources Inc.

4478 Market St., Suite 705 Ventura, CA 93003

(805) 644-0470

Bradley & Sons Drilling 3625 S. Highland Del Rey, CA 93616 (559) 441-1401 Ifland Surveying 303 Potrero Street Santa Cruz, CA 95060 (831) 426-7941

Monterey Bay Analytical Services 4 Justin Court, Suite D

Monterey, CA 93940 (831) 375-6227

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Appendix D – Well Completion Report

Monitoring well construction project (SC20 A, B, and C) Polo grounds park, Santa Cruz County, California

June 2009

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PUEBLO WATER RESOURCES, INC • 4478 Market Street, Suite 705 • Ventura, CA 93003 805.644.0470 • 805.644.0480 FAX • www.pueblo-water.com

MONITORING WELL CONSTRUCTION PROJECT

(SC-20 A, B, and C) POLO GROUNDS PARK

SANTA CRUZ COUNTY, CALIFORNIA

Soquel Creek Water District

WELL COMPLETION REPORT

Prepared for:

HYDROMETRICS LLC 519 17th Street, Suite 500

Oakland, CA 94612

June 2009

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F:\PROJECTS\09-0030\09-0031 PG RPT JUN09.DOC

- ES1 -

Page EXECUTIVE SUMMARY ... ES1 INTRODUCTION ... 1 GENERAL STATEMENT ... 1 FINDINGS... 2

PILOT DRILLING ... 2 WELL CONSTRUCTION AND DEVELOPMENT... 2 WATER QUALITY... 3 CONCLUSIONS... 4

TABLES

ES-1 Summary of Well Information... ES1 ES-2 Well Cluster Construction Summary ... ES2 ES-3 Project Chronology... ES2 1 Well Completion Summary... 2 2 Summary of Water Quality Data ... 4

PLATES

Well Location Map ... 1 Well Construction Drawing... 2 Well Completions and Hydrogeology... 3

APPENDICES

APPENDIX A: WELL PERMITS, WELL LOGS, AND SURVEY DATA APPENDIX B: WATER QUALITY DATA

APPENDIX C: PROJECT PHOTOGRAPHS

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F:\PROJECTS\09-0030\09-0031 PG RPT JUN09.DOC

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Three monitoring wells were drilled and installe d for the So quel Creek Water District at Polo Grounds County Park, located at 2255 Huntington Avenue, in Aptos, California . The wells were constructed as a monitoring well cluster, where individual wells of varying depths were installed in three separate boreholes on the same site. T ables ES-1 through ES-3 provide a summary of the installation, location, and design of the wells.

Table ES-1. Summary of Well Information Polo Grounds Park Well Cluster

Well Cluster I.D.: Polo Grounds Park Wells (deep, intermediate, shallow) Well Owner: Soquel Creek Water District

Owner Well No. : SC-20A (deep), 20B (intermediate), and 20C (shallow) Well Location: Polo Grounds Park, 2255 Huntington Avenue, Aptos, CA.

Township/Range/Section: T11S R1E S8 GPS Coordinates: N 36o 58’ W 121o 52’

Approximate Site Elevation: 175 feet above mean sea level

Well Contractor: Bradley and Sons, Inc., Madera, California Drilling Method: Direct Rotary, with bentonite and additives

Drill Rig: Versa Drill 1555

Completion Date: May 2009

Total Pilot Hole Depth: 420 feet

Geophysical Data: Welenco: SP, Electric, Gamma Consultants: HydroMetrics LLC, Oakland, CA

Pueblo Water Resources, Inc., Ventura CA Martin B. Feeney, Ventura, CA

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- ES3 -

Table ES-2. Well Construction Details Polo Grounds Park Well Cluster

SC-20 A (Deep Well)

SC-20 B (Intermediate Well)

SC-20 C (Shallow Well) Top of Well Vault Elevation

(ft., m.s.l.) 174.37 174.29 174.32

Top of Casing Elevation

(north side; ft., m.s.l.) 174.16 174.02 173.93

Total Drilled Depth, (ft.) 420 205 105

Borehole Diameter (in.) 8.75 8.75 8.75

Casing Depth (ft.) 385 200 100

Casing Diameter (in.) 2 2 2

Casing Material PVC

Casing Grade Sch. 80 Sch. 80 Sch. 80

Screened Interval (ft.) 355 to 375 160 to 190 75 to 95

Gravel Pack Material Lone Star No. 8

Depth of Annular Seal (ft.) 343 150 65

Table ES-3. Project Chronology Polo Grounds Park Well Cluster

Date Activity

May 11, 2009 Contractor Mobilization May 12, 2009 Commence Pilot Hole Drilling

May 13, 2009 Complete Pilot Hole and Run Geophysical Log May 14-15, 2009 Construct Deep Well

May 19-20, 2009 Drill and Construct Intermediate Well May 21-22, 2009 Drill and Construct Shallow Well May 26-27, 2009 Develop Wells

May 27, 2009 Collect Water Quality Samples (Deep/Intermediate)

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F:\PROJECTS\09-0030\09-0032 polo grounds report june 2009.doc

- 1 - GENERAL STATEMENT

This report provides documentation of the drilli ng and construction of the Soquel Creek Water District’s (SqCWD) Polo Grounds Park Monitoring Well Cluster. The work associated with the project was performed between May 11 and May 27, 2009.

The wells are located at Polo Groun ds County Park, 2255 Huntington Avenue in Ap tos, California. The well site is situated at the far northeast portion of the park, at the northern end of what is referred to as the ‘Great Meadow’. Plate 1 shows the site an d well locations. Three wells are included in the cluster, and are informally referred to as Po lo Grounds Park Deep, Polo Grounds Park Int ermediate, and Polo Grounds Par k Shallow. The wells have been incorporated into the District’s monitoring well n etwork, and are formally identified as SC-20A, SC-20B, and SC-20C, respectively.

Bradley and Sons, Inc., of Madera, California served as the drilling and well construction Contractor for the project. HydroMetrics L LC served as hydrogeologic consultant to SqCWD.

HydroMetrics LLC coordinated the project and prepared the specifications for the well drilling and construction. Pueblo Water Resources, Inc. (PWR) and Martin Feeney (Feeney), Hydrogeologist, were subconsultants to HydroMetrics LLC, and served as field re presentative for SqCWD and HydroMetrics LL C. PWR and Feeney assisted with project coordination, provided oversight duri ng the collection of hydrogeologic data, documented drilling and well construction activities, and served as a liaison for HydroMetrics LLC and SqCWD. Welenco of Salinas, California provided geophysical survey services for the pr oject. Mo nterey Bay Analytical Services, Inc. of Monterey, California performed analyses of water quality samples.

This report compiles all relevant data pertaining to the project, including:

Lithologic and geophysical data;

Well construction details;

Water quality sampling and analytical results;

Project photographs.

The documentation cited above is provided within the text of the report and is included in the following appendices:

Appendix A - Well Permits, Well Logs, and Survey Data

Appendix B - Water Quality Data

Appendix C - Project Photographs

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F:\PROJECTS\09-0030\09-0032 polo grounds report june 2009.doc

- 2 - PILOT BOREHOLE DRILLING

Drilling was performed using the direct rotary method with a bentonite based fluid. Fluid was circulated and con ditioned in a system using mecha nical separation of solid s. The p ilot bore diameter was 8.75 inches. Drill pipe length s were twenty feet, and following ad vancement of each joint of pipe th e fluid was circulated and cleaned to provid e representative cutting samples and a balanced column of fluid. PW R collected cutting samples throughout the pilot boring and prepared a lithologic log of the borehole.

The total depth of the p ilot bore was 420 feet. A geoph ysical survey of the well was performed immediately after completing the pilot borehole. The g eophysical log include s measurements of natural gamma radiation, spontaneou s potential, short-and long-normal resistivities, and single point resistance. Appendix A contains the lithologic log, the geophysical log, and photographs of the cutting samples.

WELL CONSTRUCTION AND DEVELOPMENT

The clustered well approach (several wells, separate boreholes) to multiple completions at the site was selected over the nested well approach (several wells within the same borehole) because of the greater confidence in achieving complete isolation of separate completion zones.

The well co mpletion plan was developed by HydroMetrics LLC, with in put from PWR, Feeney, and SqCWD. The objectives of the well completion plan included monitoring isolate d zones within the aquifer from which the nearby Polo Grounds Park Well produces water, an d monitoring the shallowest groundwater at the sit e that may be in communication with Valencia Creek.

A summary of the monitoring well completion depths are provided in Table 1.

Table 1. Well Completion Summary Polo Grounds Park Well Cluster

SC-20 A (Deep Well)

SC-20 B (Intermediate Well)

SC-20 C (Shallow Well)

Total Drilled Depth, (ft.) 420 205 105

Casing Depth (ft.) 385 200 100

Casing Diameter (in.) 2 2 2

Screened Interval (ft.) 355 to 375 160 to 190 75 to 95

Depth of Cement Grout

Annular Seal (ft.) 343 150 65

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- 3 -

The well casings consist of flush-threaded, Schedule 80 PVC. Well screens con sist of perforated sections of casing with 0 .040-inch, machine cut horizontal slots. The casings were centered in the borehole with cen tering guides placed immediately above and b elow the well screens, and at approximate 80-feet intervals throughout the blank po rtions of the monitoring wells.

Gravel pack for all of t he wells consisted of a n RMC Pacific Materials No. 8 ble nd.

Gravel pack was installed into the annulus t hrough tremie pipe. The gravel packing was monitored and documented, and the final depth to the gravel pack was measured and recorded once gravel placement operations were completed.

Bentonite chip transit ion seals were placed in the annulu s on top of the gravel pack (through tremie pipe). One bag of bentonite chips translated to approximately 4 to 5 linear feet of annulus. Cement grout annular seals were then installed in each of the wells. The grout consisted of a 10-sack sand slurry supplied by Granite Rock. Benton ite was add ed to the mixture to s low the curing process, reduce the heat generated during curing, and protect the integrity of t he well ca sings. A Sa nta Cruz County inspe ctor was pr esent to wit ness sealing operations for each well.

Each well was provided with a water-tight, flush-mounted, traffic-rated circular well v ault set in place with concrete.

A drawing showing the general construction features of the wells is provided on Plate 2.

A depiction of the completion of each well with respe ct to the subsurface h ydrogeology (represented by the lithologic and geophysical logs) is presented on Plate 3.

The wells were developed by airlifting and surg ing. Development was performed until the discharge of each well following surges remained relatively clear.

Following development of each of the wells, water levels were allowed to recover, an d the following initial static water levels were measured (depths to water in feet from top of PVC casings):

Polo Grounds Deep – 139.22 feet depth to water

Polo Grounds Intermediate – 142.60 feet depth to water

Polo Grounds Shallow – dry, no standing water.

WATER QUALITY

The wells (deep and intermediate) were sa mpled during the final stages of well development. Samples were delivered to Monterey Bay Analytical Services laboratory, where they were analyzed for basic general mineral constituents. A summary of the analytical data is

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- 4 -

Table 2. Summary of Water Quality Data Polo Grounds Park Well Cluster

SC-20 B (Intermediate Well)

SC-20 A (Deep Well)

Sample Date May 27, 2009 May 27, 2009

Specific Conductance, µmhos/cm 516 487

TDS, mg/l 335 313

Calcium, mg/l 27 24

Magnesium, mg/l 36 34

Potassium, mg/l 2 2

Sodium, mg/l 26 23

Chloride, mg/l 25 23

Sulfate, mg/l 34 19

Bicarbonate (as HCO3), mg/l 233 243

Iron, µg/l 273 ND (< 50)

Manganese, µg/l 35 209

Nitrate (NO3), mg/l 3 ND (< 1)

ND – Not Detected

Shallow well dry – no sample collected.

CONCLUSIONS

Soquel Creek Water District’s Polo Grounds Park Monitoring Well Construction P roject was successfully executed and the following objectives for the project were met:

Acquiring key hydrogeologic data at the site.

Characterizing the aquifer and establishing baseline hydrogeologic conditions.

Installing discrete and separate monitoring well s to allow for monitoring of water level and water quality trends.

Providing data that may be used for future production well design.

This report has been prepared for the exclusive use of HydroMetrics LLC, for specific application to the Polo Grounds Pa rk site in S anta Cruz County, Cal ifornia. The findings, conclusions, and recommendation s presented herein were prepared in accordance with generally accepted hydrogeologic practices. No other warranty, expressed or implied, is made.

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PLATES

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Water-Tight Well Vault

'10-Sack' Cement Sand Slurry Sanitary Seal

8.75" Diam. Borehole

PVC Flush-Threaded Well Casing, 2-inch Diameter, Schedule 80

Casing Centralizer

Bentonite Pellet Transitional Seal

PVC Well Screen, 0.040-inch Slots

PVC Casing Cellar

Gravel Pack, RMC Pacific Materials #8

PLATE 2. WELL CONSTRUCTION DRAWING SC-20 Monitoring Well Cluster (Polo Grounds Park) HydroMetrics LLC/Soquel Creek Water District

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PLATE 3. WELL COMPLETIONS AND HYDROGEOLOGY SC-20 Monitoring Well Cluster (Polo Grounds Park) HydroMetrics LLC/Soquel Creek Water District 450

400 350 300 250 200 150 100 50 0

Depth from Ground Surface, in feet

-275 -250 -225 -200 -175 -150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150 175

ApproximateElevation,infeet-msl

-50 -40 -30 -20 -10 0

millivolts 0 40 80 120 API Counts

0 20 40 60 80 100

Ohm-M 0 10 20 30 40 50 Ohms

Dark Brown Sandy Clay Brown Sandy Clay

Brownish Gray Sand, Gravel

Grayish Brown Clay/Claystone

Dark Grayish Brown Fine Sand

Dark Gray to Black Clay/Claystone

Bluish Gray Fine Sand

Bluish Gray Clayey Sand/Sandy Clay Brownish Gray Clay

65 75

95 105

150 160

190

205

343 355

375

420

SP Gamma 64" Resistivity

Single

Point Resistance Deep

WELL COMPLETIONS

Shallow Intermediate

LITHOLOGY

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APPENDIX A

WELL PERMITS, WELL LOGS, AND SURVEY DATA

Figure

Updating...

References