HomeMy WebLinkAboutLeach Field Analysis Letter5155 VENTURE PARKWAY • REDDING, CA 96002 • (530) 244-0202
June 7, 2022
2630.10
SENT BY EMAIL ONLY
kandoe@palermok8.org
Kathleen Andoe-Nolind, Superintendent
Palermo Union Elementary School District
7390 Bulldog Way
Palermo, CA 95968
Dear Kathleen,
Subject: Honcut Elementary School Water Main Alignment and Relocation of Leach Field Analysis
Palermo Union Elementary School District (District) applied for Technical Assistance through the
State Water Resources Control Board (SWRCB) to complete planning efforts for construction of a
new well as part of a Corrective Action Plan required by Butte County Environmental Health (BCEH).
The purpose of this letter is to analyze three different alignments for new water to the three
existing classrooms.
A technical memorandum, dated December 2021, was completed discussing the existing
deficiencies within the Honcut School water system. The proposed project includes the
following items:
• Concrete masonry unit (CMU) block well building to house the new well with a separate
chlorine room.
o The new building is sized large enough to house future treatment equipment if
needed.
• 50 GPM submersible well pump.
• Chlorine day tank, pump, and appurtenances.
• 400-gallon bladder tank.
• Piping and appurtenances to connect the new well to all three classrooms and irrigation
system.
• Automatic transfer switch and connection to a new generator. (Generator is not
included in the Scope of Work for this project.)
• Fencing to protect the water system infrastructure.
• Destroy the old well per Department of Water Resources (DWR) Bulletin 74-81 and 74-90.
• Remove the building and all aboveground appurtenances associated with the old well.
Palermo Union Elementary School District June 7, 2022
Page 2 2630.10
Due to the unknown condition of the water line behind the three classrooms and the uncertainty
of the water main’s location behind the classrooms, it was recommended the new water main
extend all the way to Classroom No. 1 and a stub out for Classroom No. 2 and the future modular
building. Classroom No. 2 currently does not have any water fixtures inside the building. There
are three alternatives for the water main alignment, see Figure 1. The advantages and
disadvantages of each alternative alignment are discussed herein. A preliminary construction
cost estimate for each alternative is also included.
Alternative 1 – Water Main Alignment South of the Classrooms
From the new well, this alignment crosses East Street, follows the fence line to the west end of
the basketball court, and cuts through the new asphalt to Classroom No. 3 and south of the
classrooms to Classroom No. 1. In this alternative, the leach field would remain as is.
Advantages:
• Construction costs are less than other alternatives.
Disadvantages:
• Has approximately nine feet of horizontal separation and unknown vertical separation
from the school’s existing leach field. Per California Code of Regulations, Title 22,
Section 64572, new water supply lines shall not be installed in the same trench as any
pipeline conveying untreated, primary, or secondary treated sewage and shall be at
least 25 feet horizontally from the nearest edge of septic tank and sewage leach field.
Since the new water main cannot meet the minimum separation requirements from the
existing leach field, it is recommended a dual-wall water pipe be installed in this area.
This solution will need to be approved by Division of Drinking Water (DDW) and BCEH.
o Less than one foot of horizontal separation from the septic tank.
o New water supply will cross over the sewer lateral for each classroom (two
crossings on pipeline containing sewer).
o Leaks in dual-wall pipe are more difficult to detect. If the District ever needed to
replace the dual-wall pipe, they will have to special order the pipe. In other
words, a dual-wall pipe that is NSF approved cannot be found in local hardware
stores. The closest supplier is located over an hour away in either Rocklin or
Sacramento, California.
• Contractor must hand dig approximately 70 feet behind the classrooms due to unknown
utilities and their location.
Preliminary Construction Cost Estimate:
A preliminary construction cost estimate is included in Table 1. Since all project components
will be the same within the well building, they are not included in this preliminary construction
cost estimate. As can be seen therein, the construction cost is approximately $44,600. It
should be noted, budgetary cost estimates are likely to change depending on how busy
suppliers and contractors are at bid time.
Palermo Union Elementary School District June 7, 2022
Page 3 2630.10
Table 1 – Water Main Alternative 1 – Preliminary Cost Estimate
No. Item Qty Unit Unit Cost Total Cost
1 Construction Cost
2 Water Main
3 2-inch Water Main w/Class "C" Bkfl 65 LF $100 $6,500
4 2-inch Water Main w/Class "A1" Bkfl 55 LF $160 $8,800
5 2-inch Water Main w/Class "A5" Bkfl 25 LF $180 $4,500
6 2-inch Dual-Wall Water Main w/Class "A3" Bkfl 25 LF $225 $5,625
7 2-inch Dual-Wall Water Main w/Class "C" Bkfl - Hand Dig 70 LF $200 $14,000
8 1-inch Water Main w/Class "C" Bkfl 10 LF $100 $1,000
9 1-inch Gate Valve 4 EA $40 $160
10 Water Main Construction Cost Subtotal: $40,585
11 Contingency at 10%: $4,000
12 Construction Cost Total: $44,600
Notes:
1. All costs are in May 2022 dollars (ENR CCI = 13,004).
Alternative 2 – Water Main Alignment Follows Fence Line
This alignment crosses East Street and follows the fence line south of the classrooms to the tie-in
at Classroom No. 1. This alternative will require relocation of the leach field. There are a few
factors to be considered when installing/replacing a septic system and leach field including:
• Is the old septic tank watertight and sized correctly?
• Will pumping be required to relocate the leach field?
• What are the soil properties of the new location?
o Will the soil allow for percolation?
BCEH has the following requirements for a new septic system:
• Must meet current code.
• Soils evaluation/percolation test must be completed.
• Must meet Butte County (County) setback requirements from existing property lines,
potable water wells, and other leach fields as shown in Table 2. PACE Engineering, Inc. (PACE)
has completed preliminary research of the neighboring systems, and County setback
requirements can be met, see Figure 1.
Palermo Union Elementary School District June 7, 2022
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Table 2 - Butte County Septic System Location and Setbacks
Distance Required From From Drain Field From Septic Tank, ATU, or
Lined Sand Filter
Public well 150 ft 150 ft
Private well 100 ft 50 ft
Other wells, excluding monitoring wells 100 ft 50 ft
Reservoirs or lakes (downslope from wastewater
system) 200 ft 50 ft
Reservoirs or lakes (upslope from wastewater
system) 100 ft 50 ft
Year-round springs, streams, creeks, or ponds 100 ft 50 ft
Intermittent streams and drainage swales 50 ft 50 ft
Cuts manmade in excess of 2.5 ft or escarpments 4x height of bank to a
maximum of 50 ft 20 ft
Property lines and foundation lines of any structure,
including garages, out buildings, in-ground
swimming pools, and/or water lines
5 ft 5 ft
Public access easement 20 ft 20 ft
Other easements Clear Clear
The County also requires a Certified Designer be involved since the septic system is for a school.
PACE reached out to a handful of Certified Designers on the County’s current list of approved
designers to include the average cost for design in the preliminary construction cost estimate
for this alternative.
The County has also indicated that if the leach field will be on a neighboring property, even if it
is owned by the District, the property will need to have a Deed Restriction recorded.
Advantages:
• Requires less fittings.
• Alignment can stay in a straight line and not under asphalt.
• Per California Code of Regulations, Title 22, Section 64572, horizontal and vertical
separation requirements are met even when crossing perpendicular over the new leach
line, including concrete encasement at crossing.
o Only one crossing of any pipeline containing sewer.
• Same type of pipe through entire pipe alignment (i.e., dual-wall pipe is not needed).
Disadvantages:
• Must have County-approved Certified Designer involved.
• District must file a Deed Restriction.
Preliminary Construction Cost Estimate:
A preliminary construction cost estimate is included in Table 3. Since all project components
will be the same within the well building, they are not included in this preliminary construction
cost estimate. As can be seen therein, the construction cost is approximately $84,600.
Palermo Union Elementary School District June 7, 2022
Page 5 2630.10
While the preliminary construction cost estimate includes the cost to complete percolation
testing, the following assumptions were made:
• Soils are such that percolation can occur.
• Pumping will not be required from the septic tank to the new leach field.
• The existing septic tank does not need to be resized but will be replaced to meet current
code requirements.
Table 3 – Water Main Alternative 2 – Preliminary Cost Estimate
No. Item Qty Unit Unit Cost Total Cost
1 Construction Cost
2 Water Main
3 2-inch Water Main w/Class "A1" Bkfl 55 LF $160 $8,800
4 2-inch Water Main w/Class "A5" Bkfl 25 LF $180 $4,500
5 2-inch Water Main w/Class "C" Bkfl 155 LF $100 $15,500
6 1-inch Water Main w/Class "C" Bkfl 30 LF $100 $3,000
7 1-inch Gate Valve 4 EA $30 $120
8 Water Main Construction Cost Subtotal: $31,920
9 Leach Field
10 Site Evaluation with County 1 LS $500 $500
11 Certified Designer Cost 1 LS $2,500 $2,500
12 Percolation Testing and Analysis 1 LS $2,000 $2,000
13 New Septic Tank and Leach Field 1 LS $40,000 $40,000
14 Leach Field Construction Cost Subtotal: $45,000
15 Construction Cost Subtotal: $76,920
16 Contingency at 10%: $7,700
17 Construction Cost Total: $84,600
Notes:
1. All costs are in May 2022 dollars (ENR CCI = 13,004).
Alternative 3 – Water Main Alignment North of the Classrooms
From the new well, this alignment crosses East Street and cuts through the playground asphalt
north of the three classrooms. A service line for Classroom Nos. 2 and 3 will run along the east
side of Classroom No. 3 and south of Classroom No. 3, immediately behind the building, to
Classroom No. 2. A service line for Classroom No. 1 and the future modular building will run
along the west side of Classroom No. 1 and then on the south side of Classroom No. 1 to its
connection point. In this alternative, the leach field will remain as is.
Advantages:
• Per California Code of Regulations, Title 22, Section 64572, horizontal and vertical
separation requirements are met, except for the service line behind Classroom Nos. 1 and 3.
o These service lines would cross over the sewer service lateral for each classroom.
(Two crossings of pipeline containing sewer.)
Palermo Union Elementary School District June 7, 2022
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Disadvantages:
• Water main would be under the playground asphalt.
• Per California Code of Regulations, Title 22, Section 64572, horizontal separation
requirements cannot be met for the approximate 60 feet of service line behind
Classroom Nos. 1 and 3.
Preliminary Construction Cost Estimate:
A preliminary construction cost estimate is included in Table 4. Since all project components
will be the same within the well building, they are not included in this preliminary construction
cost estimate. As can be seen therein, the construction cost is approximately $89,700.
Table 4 – Water Main Alternative 3 – Preliminary Cost Estimate
No. Item Qty Unit Unit Cost Total Cost
1 Construction Cost
2 Water Main
3 2-inch Water Main w/Class "C" Bkfl 55 LF $100 $5,500
4 2-inch Water Main w/Class "A1" Bkfl 45 LF $160 $7,200
5 2-inch Water Main w/Class "A5" Bkfl 20 LF $180 $3,600
6 2-inch Water Main w/Class "A3" Bkfl 250 LF $225 $56,250
7 2-inch Water Main w/Class "C" Bkfl - Hand Dig 25 LF $200 $5,000
8 1-inch Water Main w/Class "C" Bkfl 40 LF $100 $4,000
9 1-inch Gate Valve 4 EA $40 $160
10 Water Main Construction Cost Subtotal: $81,710
11 Contingency at 10%: $8,000
12 Construction Cost Total: $89,700
Notes: 1. All costs are in May 2022 dollars (ENR CCI = 13,004).
Recommended Alternative
Alternative 1 does not meet the California Code of Regulations, Title 22, Section 64572
horizontal separation requirements of 25 feet. This alternative also requires specialty pipe to
be installed that will not only be difficult but also costly for the District to replace in the future.
As such, this alternative is not recommended.
While Alternative 3 does not require relocation of the leach field, California Code of Regulations,
Title 22, Section 64572 horizontal separation requirements still cannot be met behind the
classrooms. Alternative 2 is the only alternative where the separation requirements can be met.
Assuming percolation can occur, pumping is not required, and the existing septic tank does not
need to be resized, Alternative 2 is also the most cost-effective option. Therefore, Alternative 2
is the recommended alternative.
Palermo Union Elementary School District June 7, 2022
Page 7 2630.10
PACE would like to thank District staff for their able assistance in its preparation. Please contact
us with any questions.
Sincerely,
Nicole Humphreys
Staff Engineer
Enclosure
M:\Jobs\2630 UEI CSUS\2630.10 Honcut School Well\Design\Leach Field\Leach Field Analysis Letter.docx
X X X X XXXX
XX X X X
HB
EE
E EE
P
W
XXXXXXXXXX XXXXX1" = 20'9.6'18'9'EAST ST(E) STORAGE
BLDG
ROOM 1 ROOM 2 ROOM 3
1+40.89
APPROX LOCATION OF
FUTURE MODULAR BLDG
APN: 028-073-014
(E) SHED
(E) AC
APN:028-073-001
APN:028-074-001(E) WELL BLDG
AND WELL
(E) SCHOOL
LEACH LINE
(E) SCHOOL
SEPTIC TANK
APPROX LOCATION
OF GENERATOR
(INSTALLED BY OTHERS)
APPROX 100' RADIUS FROM
NEAREST NEIGHBORING WELL
(N) 3" IRRIG W
(N) 2" PW
(E) WELL
SEE NOTE 2
PROPERTY
BOUNDARY
DUAL-WALL
PIPE
36.7'(E) APPROX PROP
BOUNDARY, TYP, SEE NOTE 17.1'0.9'(N) CMU
WELL BLDG
11'8'FIGURE 1
DATE: 5/12/22
JOB # 2630.10
WATER MAIN ALIGNMENT
ALTERNATIVES
NOTES:
1.PACE CONDUCTED RECORDS RESEARCH FROM READILY AVAILABLE SOURCES INCLUDING BUTTE COUNTY RECORDS
TO OBTAIN THE REQUISITE RECORD DOCUMENTS THAT DESCRIBE OR DEPICT THE PROPERTY LINE FOR THIS PROJECT. ON
JULY 8, 2020, PACE CONDUCTED A FIELD SURVEY TO LOCATE A SUFFICIENT NUMBER OF CONTROLLING MONUMENTS
AND/OR PHYSICAL FEATURES TO GEOGRAPHICALLY CORRELATE THE OBTAINED RECORD INFORMATION TO THE
PROJECT'S COORDINATE SYSTEM. WITH THIS INFORMATION, PACE WAS ABLE TO PREPARE AN AUTOCAD DRAWING
DEPICTING THE APPROXIMATE LOCATION OF SAID PROPERTY LINES. THE PROPERTY LINES ARE PLOTTED TO A SUFFICIENT
ACCURACY FOR THE DESIGN CONSTRAINTS (± SEVERAL FEET). IN THE EVENT THE DISTRICT REQUIRES A HIGHER DEGREE
OF ACCURACY FOR SPECIFIC PORTIONS OF THE PROJECT, ADDITIONAL FIELD WORK AND ANALYSIS WILL BE REQUIRED.
2.UNKNOWN UTILITIES BEHIND EXISTING CLASSROOMS. CONTRACTOR TO HAND DIG THIS AREA. (N) POTABLE WATER
SHALL BE DUAL-WALL PIPE AND HAVE 24 INCHES OF COVER IN THIS AREA.
LINE LEGENDLINE LEGEND
WATER MAIN ALTERNATIVE 1 ALIGNMENT
WATER MAIN ALTERNATIVE 2 ALIGNMENT
(E) SEPTIC TANK AND LEACH FIELD
PROPOSED LEACH FIELD
LINE LEGEND
WATER MAIN ALTERNATIVE 3 ALIGNMENT