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DRAFT
SIERRA LAKES PROJECT
INTEGRATED FLOOD CONTROL,
WATER CONSERVATION,
AND
STORM WATER QUALITY
MANAGEMENT CONCEPT
August 1993
Prepared by:
Jahn M. Tettemer, President
Alan A. Swanson, Vice President, Engineering
Harold A. Vance, Consulting Engineer
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TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY ............ ............................... viii
A. An Integrated Concept .......... ............................... viii
B. Multiple Benefits ................ ............................... ix
C. Design, Installation, and Maintenance Criteria ......................... ix
D. Implementation ................. ............................... x
I. INTRODUCTION .............. ............................... 1
A. Project Location and Description .............................. 1
B. Hydrology, Water Conservation, and Water Quality Issues ........... 1
C. Purpose of Report .......... ............................... 4
D. Conclusions ............... ............................... 5
E. Recommendations .......... ............................... 8
II. BACKGROUND .............. ...............................
10
A.
Soil Investigations ......... ...............................
10
B.
Infiltration Tests .......... ...............................
10
C .
Hydrol ogy ............... ...............................
12
D.
Golf Course Flood Water Storage Basins
.......................
13
E.
Flood Routing- Infiltration Study Findings
......................
13
F.
Infiltration Facility Concept .. ...............................
14
G.
Water Quality Considerations ...............................
16
III. FIELD INFILTRATION TEST SETUP ............................
18
A.
Test Pit Location ......... ...............................
18
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TABLE OF CONTENTS
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B. Water Delivery and Metering ............................... 18
C. Steady State Flow Conditions ............................... 19
D. Meter Verification ........ ............................... 19
E. Test Pit Filling ........... ............................... 19
F. Test Sequence ............ ............................... 20
IV. FIELD INFILTRATION TEST PROGRAM ......................... 21
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A. Test Programs ............ ............................... 21
B. Test Program No. 1 ........ ............................... 21
1. Test Pit Configuration . ............................... 21
2. Results of Test Program No. 1 ......................... 22
3. Investigation of Edge Conditions ........................ 22
C. Test Program No. 2 ........ ............................... 23
1. Test Pit Configuration . ............................... 23
2. Results of Test Program No. 2 ......................... 24
D. Evaluation of Test Program Nos. 1 and 2 ...................... 24
1. Selection and Testing of Rapid Sand Filter Material ......... 24
2. Sizing of the Sand Filter .............................. 26
E. Test Program No. 3 ........ ............................... 27
1. Test Pit Configuration . ............................... 27
2. Results of Test Program No. 3 ......................... 28
F. Test Program No. 4 ........ ............................... 29
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TABLE OF CONTENTS
Page
1. Test Pit Configuration . ...............................
29
2. Results of Test Program No. 4 .........................
30
G.
Test Program No. 5 ........ ...............................
32
1. Test Pit Configuration . ...............................
32
2. Results of Test Program No. 5 .........................
33
H.
Test Program No. 6 .......................................
33
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1. Test Pit Configuration . ...............................
33
2. Results of Test Program No. 6 .........................
33
V.
DISCUSSION OF TEST PROGRAM RESU LTS .......... • • • •
35
A.
Evaluation of Laboratory Flow Test Data ......................
35
and Piezometer Data
.
B.
Flownet Analyses ......... ...............................
37
1. Flownet Construction . ...............................
37
2. Flownet Analyses .... ...............................
38
C.
Effective Infiltration Rates .. ...............................
39
D.
Size Relationship of Sand Filter Area to Infiltration Area ..........
40
VI.
RECOMMENDED DESIGN PARAMETERS .......................
41
41
A.
Ratio of Sand Filter Area to Infiltration Area ...................
B.
Infiltration Rate Curve ..... ...............................
41
1. Sand Filter Maintenance Criteria .......................
41
2. Recommended Infiltration Rate Curve ...................
41
C.
Sand Filter /Gravel Layer Material Specifications .................
42
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TABLE OF CONTENTS
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1. Gravel Layer ....... ...............................
42
2.. Sand Filter ......... ...............................
43
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3. Filter Fabric ........ ...............................
43
1
D. Safety Factor ............ ...............................
43
E. Possible Failure Modes and Mitigation ........................
48
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VII.
OPERATION AND MAINTENANCE REQUIREMENTS ..............
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A. Delivery System .......... ...............................
51
1. Off -Site Flood Flows .. ...............................
51
Flows ............. ..
2. On -Site FloodF1 o •••••••••••- ••••••
52
B. Water Quality Facilities .... ...............................
53
1. Description and Purpose of Proposed Facilities .............
53
2. Objective of the Operation and Maintenance Program .......
55
3. Maintenance Philosophy ..............................
56
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4. Maintenance Program Elements ........................
56
5. Interim Operation of the Wetland Facilities ...............
58
6. Preparation of the Wetland Field Operations Manual ........
62
7. Wetland Monitoring .. ...............................
64
C. Sand Filter Infiltration Facilities .............................
64
67
VIII.
RESPONSIBILITY FOR OPERATION, MAINTENANCE . .............
AND MONITORING
67
A. Flood Control and Storm Drain Delivery Systems ................
B. Water Quality Wetlands .... ...............................
67
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TABLE OF CONTENTS
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1. From Construction to 2 Years Later ..................... 68
2. After Two Years ..... ............................... 68
C. Sand Filter Infiltration Facilities ............................. 69
IX. ROLE AND RESPONSIBILITY OF THE DEVELOPER ............... 70
AND GOVERNMENT AGENCIES
A. Lewis Homes ............ ............................... 70
B. City of Fontana ........... ............................... 71
C. San Bernardino County ..... ............................... 72
Transportation/Flood Control District
D. Golf Course Owner /Operator ............................... 73
X. LIABILITY .................. ............................... 74
XI. PHASING OF CONSTRUCTION .. ............................... 75
XII. FINANCING OF CONSTRUCTION AND OPERATION . .............. 76
MAINTENANCE, MONITORING, AND REPORTING
XIII. FIGURES .................... ............................... 77
Figure 1: Location Map
Figure 2: Conceptual Development and Recharge
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Basin Location Plan
Figure 3:
Location Map, RMA Group Percolation
Tests
Figure 4:
Typical Water Quality Wetland Facility
Figure 5:
Sand Filter /Gravel Layer Infiltration
Concept
Figure 6:
Test Program No. 1, Plan and Section
Figure 7:
Infiltration Test Results, Depth vs.
Rate of Infiltration, Test Program No. 1
Figure 8:
Infiltration Test Results, Flownet Analysis,
Test Program No. 1
Figure 9:
Test Program No. 2, Plan and Section
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Page 1:
Page
Figure 10:
Infiltration Test Results, Depth vs.
Page 2:
Rate of Infiltration, Test Program
Figure 11:
Nos. 1 and 2
Sand Gradation Plots
Figure 12:
Laboratory Flow Test Results
Figure 13:
Figure 14:
Sample Computation of Sand Filter Size
Test Program No. 3, Plan and Section
Figure 15:
Infiltration Test Results, Depth vs.
Page 7:
Rate of Infiltration, Test Program Nos.
1, 2, and 3
Figure 16:
Test Program Nos. 4A, 4B, 4C, Plan and
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Figure 17:
Section
Infiltration Test Results, Depth vs.
Rate of Infiltration, Test Program Nos.
3, 4A, 413, 4C
Figure 18:
Silt Migration Data
Figure 19:
Test Program No. 5, Plan and Section
Figure 20:
Infiltration Test Results, Depth vs.
Rate of Infiltration, Test Program Nos.
3 and 5
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Figure 21:
Test Program No. 6, Plan and Section
Figure 22:
Infiltration Test Results, Depth vs.
Rate of Infiltration, Test Program Nos.
3 and 6
Figure 23:
Recommended Design Infiltration Rate
Curve, Location I
Figure 24:
Proposed Off -Site and On -Site Drainage
Facilities
Figure 25:
Typical Rapid Sand Filter Testing Locations
XIV. PHOTOGRAPHS .............. ............................... 78
Page 1:
Photographs of Flow Meters and Transmission
Line
Page 2:
Test Program No. 1
Page 3:
Test Program No. 2
Page 4:
Test Program No. 3
Page 5:
Test Program No. 4
Page 6:
Test Program No. 5
Page 7:
Test Program No. 6
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XV. APPENDICES (under separate cover) .............................. 79
LIST OF TABLES
Table 1: Summary of Auger Hole Infiltration Tests ...................... 10
Table 2: Comparison of Computed (Laboratory) and ..................... 35
Measured (Piezometers) Loss of Head in Feet
through the Sand Filter
Table 3: Adjustment Factors to be Applied to Infiltration ................. 39
Rate Design Curve Ordinates for Varying
Infiltration Area Widths
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Appendix
A:
RMA Infiltration Test Reports
1. Soil Percolation Report for
Sierra Lakes, Highland and
Sierra Avenues
2. Additional Soils Percolation Testing
for Feasibility of Onsite Storm Water
Appendix
B:
Retention, 640 Acre Sierra Lakes Project
Hydrologic Feasibility Study
Appendix
C:
Laboratory Test Results
1. Particle Size Analysis
2. Flow Test Data
Appendix
D:
Field Data Records
Appendix
E:
List of Visitors at Test Site
Appendix
F:
Pre -Storm Season Inspection Report
Form
Appendix
G:
Wetland Monitoring and Inspection
Form
LIST OF TABLES
Table 1: Summary of Auger Hole Infiltration Tests ...................... 10
Table 2: Comparison of Computed (Laboratory) and ..................... 35
Measured (Piezometers) Loss of Head in Feet
through the Sand Filter
Table 3: Adjustment Factors to be Applied to Infiltration ................. 39
Rate Design Curve Ordinates for Varying
Infiltration Area Widths
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P s i
EXECUTIVE SUMMARY
A. An Integrated Concept
This report presents a conceptual integrated flood control -water conservation -
water quality management plan for Sierra Lakes. The plan is conceptual only due
to the preliminary nature of the golf course grading plan and the flood water
collection systems. The integrated concept itself is practical and valid, soundly
based on extensive soil studies and a carefully designed and executed field testing
program to develop design criteria for infiltration facilities to be incorporated into
the golf course fairways. It has been tested by applying the San Bernardino
County Transportation/Flood Control Department (SBCTFCD) multiple -day
design storm and routing the resulting hydrographs through the system of golf
course basins.
E l It can be concluded that, due to the high infiltration rates exhibited by the porous
gravelly soil on the site, the concept can be developed into a viable plan,
compatible with the current golf course layout and development plan. Under this
concept, off -site and on -site drainage will be collected, temporarily stored in golf
course fairways gently graded to form basins, and allowed to infiltrate into the
porous alluvial soil. Special infiltration facilities resembling golf course bunkers
t will
be placed along some of the fairways to assure that planned infiltration rates
will be maintained over the long term. Special water quality wetlands will remove
drainage system so these
first -flush storm runoff and urban nuisance flow from the Y
polluted flows never enter the infiltration facilities. The water quality wetlands
will remove sediments, minimize silt build -up in the infiltration facilities, reduce
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maintenance requirements, and enhance the quality of water being infiltrated to
the aquifer. Under design flood conditions there will be no runoff from the site.
Runoff from the extreme southerly end of the site will also be managed through
infiltration systems to be incorporated into the development plan.
B. Multiple Benefits
The traditional drainage approach is to collect off -site and on -site flows, carry
them safely through the development in an adequate flood control system, and
deliver them to downstream facilities.. The concept described herein offers several
advantages over the traditional approach. By storing the water and allowing it to
infiltrate, downstream flow rates and the cost of downstream flood control works
are reduced. At the same time, the water is conserved by recharging the aquifer.
Also, due to the water quality wetlands, the quality of water infiltrated is expected
to be superior to that typical of runoff in the region. As a result of the pollutant
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removals in the water quality wetlands and the "zero- runoff' from the site, there
will be a virtual "zero- discharge" of pollutants from the site.
C. Design, Installation, and Maintenance Criteria
The report presents design criteria for the infiltration facilities based on the field
infiltration tests. Monitoring, maintenance, and operational criteria and
procedures are presented to assure the continued reliable performance of the
infiltration facilities, the water quality wetlands, and the flood water collection and
conveyance system. The report describes an interim monitoring, maintenance, and
operation program for the water quality wetlands which calls for supervision by a
in he plant establishment eriod and the etlands specialist during t p p preparation of a p p
Field Operations Manual based on the experience gained during this period.
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Safety p factors to be incorporated into the design, and mitigation measures for
floods greater than the SBCTFCD design flood and other contingencies are
provided.
D.
Implementation
The report describes the steps needed to proceed with implementation, including
final design of the golf course, flood water collection and conveyance system,
water quality wetlands, infiltration facilities, and flood contingency plans. Also
described is the need to reach agreement among the agencies and private parties
involved on roles and responsibility for implementation, monitoring, maintenance,
operation, and reporting on the various system components. The liability attached
to is described.
each party
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I. INTRODUCTION
A. Project Location and Description
Curtis Avenue, on the west by Catawba Avenue, and by Citrus Avenue on
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the east.
The Sierra Lakes project is being developed by Lewis Homes of California
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as a planned community consisting of residential and commercial land uses
to be constructed around an 18 -hole golf course. The conceptual land use
plan and golf course configuration for the one square mile portion of the
project are shown on Figure 2.
B. Hydrology, Water Conservation, and Water Quality Issues
The Sierra Lakes project is located in the northern portion of the City of
Fontana (City) (Figure 1). The project site includes the one square mile
bounded on the north by Summit Avenue, on the west by Citrus Avenue,
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on the east by Sierra Avenue, and on the south by Highland Avenue. Also
included in the project area is the 60 -acre parcel bounded on the north by
Curtis Avenue, on the west by Catawba Avenue, and by Citrus Avenue on
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the east.
The Sierra Lakes project is being developed by Lewis Homes of California
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as a planned community consisting of residential and commercial land uses
to be constructed around an 18 -hole golf course. The conceptual land use
plan and golf course configuration for the one square mile portion of the
project are shown on Figure 2.
B. Hydrology, Water Conservation, and Water Quality Issues
Development of the Sierra Lakes project will require drainage and flood
control features to meet City, SBCTFCD, and Federal Flood Insurance
standards. Water quality management features or practices will be required
to meet City and SBCTFCD requirements under the National Pollutant
Discharge Elimination System (NPDES) permit issued by the Santa Ana
Regional Water Quality Control Board SARWQCB . Water conservation
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is a priority issue in the region and should be incorporated into runoff
management plans whenever feasible.
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The site is located on a broad, sloping alluvial plain or cone laid down over
geologic time by Lytle Creek. Lytle Creek passes about 2 miles north -east
of the site and does not affect the site. The plain on which the site is
located slopes from north to south. The site is subject to runoff from the
local off -site tributary drainage area immediately to the north, and from the
site itself. The off -site area consists of 440 acres. The portion of the
project area including the golf course consists of a section of land, or 640
acres gross. The southerly edge of this portion of the project is reserved
for the future Foothill Freeway and is not part of the development nor
included in the hydrology study described herein.
Various options are available for managing the runoff affecting the site.
One option is to collect the off -site and on -site water, carry it safely
through the site, and discharge it at an approved location downstream
(south) of the site. The site and its tributary drainage area are included in
an existing drainage master plan for San Sevaine Creek.
Another option, described herein, is to collect the off -site and on -site
water, store it temporarily in golf course fairways graded to form basins,
and allow it to infiltrate into the soil. This option is made possible by the
unusually high infiltration rates known to exist in the porous soils and
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of the alluvial cone. If design, maintenance, and operational
criteria can be satisfactorily developed and implemented, this option offers
the following advantages over the one described above:
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■ Savings in the cost of the San Sevaine Creek system by reducing
flow requirement;
■ Water conservation, which is a high priority objective within the City
and throughout Southern California; and
■ Enhanced groundwater quality. because the water quality
management facilities will remove first -flush storm runoff and urban
drainage system, together with any pollutants
nuisance flow from the Y
that they contain, so they never enter the infiltration facilities.
■ Enhanced surface water quality downstream of the project, because
the system produces virtually no runoff, a nd thereby discharges
virtually no pollutants.
The feasibility of this approach depends on satisfactory resolution of the
following issues:
■ Adequate collection and desilting systems for off -site and on -site
flows;
■ Adequate system of golf course fairway basins and inter -basin
conveyances within the site;
■ Adequate infiltration rates within the golf course;
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■ Adequate design of infiltration facilities; and
■ Adequate monitoring, maintenance, and operational criteria.
C. Purpose of Report
This report has been prepared to demonstrate that key issues in the above
list are satisfactorily resolved, and the remaining issues can be readily
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addressed in the design phase of the Sierra Lakes project. The report
accomplishes the following purposes:
■ Presents the hydrologic setting of the Sierra Lakes project.
• Describes flood flow rates and volumes of runoff to be managed,
including multiple -day storms, based on existing land use plans and
preliminary drainage collection assumptions.
• Describes the field testing program carried out to evaluate the
infiltration rates of the native soils on the site and of a sand filter -
gravel layer infiltration facility that can be incorporated into the golf
course design. The testing program included step -by -step testing of:
• the native soil;
• each component of the infiltration facility;
• the infiltration facility under various levels of siltation;
• the infiltration facility with silt- contaminated layers removed
and replaced with clean sand; and
• the native soil covered with golf course turf.
(12.0 A(s12.OVRmnantEended design criteria for the infiltration facility,
including:
( 12.0 the ratio of area of sand filter to gravel layer;
• the infiltration rate curve; and
• specifications for the gravel, sand, and filter fabric.
■ Evaluates possible modes of failure and presents reliable mitigation
strategies.
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■ Presents a water quality management program to remove first -flush
storm runoff and urban nuisance flow from the drainage system
upstream of the golf course fairways and infiltration facilities, to
reduce the buildup of silt in the infiltration facilities, minimize
maintenance costs, enhance the quality of the water being infiltrated,
and enhance the quality of runoff downstream of the project.
■ Develops monitoring, maintenance and operation requirements for
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the entire system, including the flood water delivery system, the
water quality wetlands, and the infiltration facilities.
■ Recommends the assignment of responsibility for monitoring,
maintenance, and operation of each component of the system.
■ Describes the roles and responsibilities of the developer, the golf
course operator, and the various public agencies involved.
■ Describes the liability assumed by the project engineers, the
developer, and the public agencies involved.
■ Discusses phasing of construction; and
■ Reviews possible financing of construction, monitoring, maintenance,
operation, and reporting.
D. Conclusions
This report is one of a series. Previous studies have suggested the validity
of the concept of incorporating golf course storage and infiltration of storm
runoff into the flood management plan for the property (Appendix A).
The Federal Emergency Management Agency, which administers the
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National Flood Insurance Program, has indicated it is aware of projects
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which have successfully used infiltration as a means of managing flood
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waters.
To determine whether the concept is actually viable for Sierra Lakes,
compatible with the development plan and golf course layout, and capable
of controlling the design floods, it was necessary to simulate design flood
routings for multiple -day storms; confirm the infiltration rates that can be
achieved within the golf course; evaluate the performance of the infiltration
system under a range of silting conditions; consider water quality
management concepts; determine monitoring, maintenance and operational
requirements; and consider legal issues, liability, and the roles of the parties
involved.
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The hydrologic analysis, flood routing studies, and field infiltration tests
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performed for this report demonstrate the feasibility of golf course storage
and infiltration, along with suitable water quality management, monitoring,
maintenance, and operation procedures, as a flood control concept for
Sierra Lakes. The golf course grading, flood delivery system, inter -basin
conveyances, and water quality wetland configurations used in this study are
conceptual only, and are subject to adjustment and refinement in the
design stage. Likewise, the location and configuration of infiltration
facilities is subject to revision and adjustment as the golf course design is
developed.
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Though such details are subject to final design adjustments, the following
conclusions are valid, based on the field tests and analyses:
■ The concept of golf course storage and infiltration, combined with
water ualit management, monitoring, maintenance, and operation,
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is a feasible concept for meeting flood control requirements for
Sierra Lakes.
■ n facility resembling a golf course sand trap or bunker,
An mfiltratio y g g p
with a gravel base layer, can be relied on to provide infiltration
rates as a function of head in accordance with the infiltration rate
curves presented herein.
■ First -flush storm flows and urban nuisance flows can be reliably
removed from the drainage system upstream of the fairways and
infiltration facilities and introduced into water quality wetlands for
treatment. These flows and any pollutants contained will never
enter the infiltration system. This arrangement removes silts from
the flow, reduces filter maintenance requirements, and enhances the
quality of water to be infiltrated into the aquifer.
■ Even when substantially impaired by siltation, the infiltration
facility described herein exhibits high infiltration capacity and can
be relied on to perform as predicted by the field tests.
■ Long term success of the infiltration system is dependent on
effective maintenance of the water quality wetlands. A responsible,
qualified organization or agency should assume responsibility for
monitoring, maintaining, and operating them as NPDES facilities in
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h criteria to be presented in the Field Operations
bed herein.
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A4X c a posed herein has the potential to recharge the
` asin in the amount of approximately 770 acre -feet per
��'�� 4 !? �,, d -•" imated value of $308,000• The present worth of this
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a,�tr�S- is $5,000,000.
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afety factors can be incorporated into the system
design to account for floods greater than the design flood and other
E ll contingencies. The safety factors are discussed in Section VI.D of
this report.
■ The integrated flood control -water conservation -water quality
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system described herein is a combination of public and private
facilities. The roles and responsibilities of all parties involved need
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to be clearly defined.
Recommendations
■ Adopt the concept of an integrated flood control -water conservation-
water quality management system as described herein for
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development and implementation in Sierra Lakes.
■ Proceed with planning and design studies to finalize the golf course
grading, the off -site and on -site drainage collector systems, the
water quality wetlands, and the infiltration facilities as conceptually
described herein.
■ Initiate discussions with the City and the SBCTFCD with a view
toward entering into an agreement covering the respective roles and
responsibilities of the parties regarding financing, facility
maintenance, monitoring, operating, reporting, and liability.
■ Adopt the design criteria, safety factors, and mitigation measures
for the golf course basins, inter -basin conveyances, and infiltration
facilities set forth in Section VI.
■ Adopt the operation and maintenance criteria set forth in Section
VII.
■ Adopt the monitoring program set forth in Section VII.
■ Adopt the water quality wetland interim operation plan described in
Section VII, including the preparation of a Field Operations
Manual.
■
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which led up to this report are described below.
A. Soil Investigations
y
During the last several years many engineering studies and field investigations
have been conducted to establish the factual basis for proceeding with the current
built n and expanded the knowledge
study. Each study and investigation w t upo e a p g
developed from the previous work. Several of the significant background studies
which led up to this report are described below.
A. Soil Investigations
y
Appendix C contains the results of sieve analyses made on soil samples
collected from the site. The samples contain relatively small percentages of
fine silt particles passing the No. 100 and No. 200 sieves, and relatively
large percentages in the coarse sand sizes represented by sieve No. 16 and
smaller and gravel sizes up to three inches. The analyses indicate
extremely porous soils which may have infiltration rates high enough to
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warrant consideration of infiltration as a component of the flood control
strategy.
B. Infiltration Tests
A number of tests have been conducted in the past to determine infiltration
rates at several locations on the property. RMA Group, the geotechnical
consultant on the project, conducted infiltration tests at auger holes drilled
at the locations shown on Figure 3. Details of these investigations are
r presented in Appendix A. The test results are summarized below:
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Summary of Auger Hole Infiltration Tests
Auger
Hole
No.
Infiltration
Rate *
(feet per day)
P -1
108.1
P -2
48.0
P -3
120.0
P -4
114.3
P -5
77.9
P -6
137.9
P -7
108.1
P -8
90.2
P -9
114.3
P -10
120.0
P -11
114.3
P -12
108.1
P -13
58.8
P -14
126.3
P -15
126.3
P -16
114.3
P -17
131.9
P -18
126.3
P -19
120.0
P -20
36.0
Average
105.1
* Calculated based on the "Falling Head
Percolation Data" published in RMA
Group's report "Soil Percolation Report
for Sierra Lakes ", November 8, 1989
(see Appendix A)
Note: RMA Group's rates are based on
the time for the water to drop 1 foot in
a 1 -foot deep test hole.
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RMA Group also conducted a more detailed infiltration test using an on-
site test pit approximately 6 feet deep with a bottom dimension of
approximately 20 feet square. The results of this test indicated infiltration
rates of up to 30 feet per day. The infiltration rates determined from these
tests are significantly greater than rates measured at existing groundwater
recharge facilities in Southern California. These high infiltration rates
suggest that infiltration can play a significant role in flood management
strategy.
deliver storm water to the fairway areas. A small portion of the south end
of the property cannot be conveniently drained to the golf course fairways
and is not included in the hydrology study. This area, however, will be
included in more detail as a part of future studies.
A HEC -1 model was developed for flood routing purposes. Two -day and
five -day storms were developed in accordance with the manual. The
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C.
Hydrology
}
To evaluate the feasibility of the infiltration concept a hydrology study was
4
performed to determine the actual flood volumes and rates of flow that
J
must be managed. The study was conducted in accordance with the
procedures set out in the SBCTFCD Hydrology Manual, assuming fully
developed watershed conditions. The study considered off -site tributary
k } or
areas as well as those within the project site which will be directed to the
golf course recharge basins, for a total of 969 acres. On -site subareas were
defined which could feasibly be provided with storm drain facilities to
deliver storm water to the fairway areas. A small portion of the south end
of the property cannot be conveniently drained to the golf course fairways
and is not included in the hydrology study. This area, however, will be
included in more detail as a part of future studies.
A HEC -1 model was developed for flood routing purposes. Two -day and
five -day storms were developed in accordance with the manual. The
08/25/93 -12-
H
ma area
drainage s, watershed soils, development, cover assumptions,
p
rainfall intensity- duration characteristics, routing schematic, and other
details are presented in Appendix B.
D. Golf Course Flood Water Storage Basins
Using the current golf course grading plan, the volume of flood water
storage that could be developed within the fairway areas was determined.
Basin stage - storage - discharge relationships were computed and input into
the HEC -1 model.
E. Flood Routing- Infiltration Study Findings
The previous field infiltration tests had identified infiltration rates of up to
30 feet per day. For the flood routing- infiltration study a value of 15 feet
per day was assumed. Infiltration was modeled as a "divert" in the HEC -1
model. To determine the required infiltration area at this infiltration rate,
a modeling criteria was established that required the golf course basins to
be drained in 24 hours. Under this criteria, it was found that 30 acres of
infiltration area would be required.
This study indicated that the infiltration concept is hydrologically feasible,
based on the generalized natural soil infiltration rates determined from the
previous field tests, and the simplified rate assumed for the study described
above. To verify its feasibility in the context of the actual golf course
environment, and to verify that a reliable infiltration facility can be
developed which can practically be maintained to retain its infiltration
capacity over the years, the present study was undertaken. Among other
08/25/93 -13-
things, the present study considers factors not previously evaluated, such as
the effects of varying head and siltation.
F. Infiltration Facility Concept
Preparatory to undertaking the field studies described herein, an infiltration
P rY g
facility concept was developed which met the following criteria:
■ Infiltration effectiveness: Drain the golf course fairways within an
acceptable time.
■ Maintainability: Be capable of restoration to the design infiltration
capacity at acceptable cost.
■ Accessibility: Be easily accessed for inspection and maintenance.
■ Reliability: Be impervious to mechanical damage, structural
deterioration, corrosion, chemical contamination, and other
foreseeable hazards.
■ Compatibility: Blend in gracefully with the golf course. If possible,
L
serve as an occasionally useable part of the golf course, such as a
sand trap or bunker.
Wq
The most promising configuration that meets these requirements is a
concept reminiscent of the simple sand filters used in municipal water
treatment facilities in the 19th century. It consists of a layer of filter sand
supported by a layer of gravel placed on the subgrade soil beneath the
surface of the golf course fairway. The gravel layer, which transmits water
to the native soil, is much larger in surface area than the sand filter. The
portion of the gravel layer outside of the sand filter is covered by native
08/25/93
-14-
fl
soil and g olf course turf. Filter fabric is placed between the layers to
prevent migration of fines into the coarser media, with resultant
impairment of infiltration capacity.
The concept described above is shown on Figure 5. The gravel layer, which
in the test program was placed directly on the subgrade soil, is 18 inches
thick. The particle size of the gravel is approximately 1.5 to 2 inches.
Filter fabric is placed over the gravel layer to prevent the movement of
�i
fines into the gravel layer. The sand filter layer is 30 inches thick.
Gradation of the sand and gravel are important considerations. It is
intended that the sand filter perform as a rapid sand filter. Rapid sand
filters generally are comprised of fairly course grained open graded sands
varying from 0.5 millimeter to over 1 millimeter in size. The open graded
condition of the sand will reduce the potential for stratification of the finer
grained materials near the bottom of the filter, and provides maximum
infiltration capacity.
The rate of infiltration for rapid sand filters is about 125 million gallons
per acre per day or approximately 2 gallons per minute per square foot. It
will be important to achieve a rate of infiltration near this value in order to
obtain a reasonable balance between the sand filter area and the area of
infiltration beneath the gravel layer. Because of the importance of these
parameters in developing a reliable infiltration system, a comprehensive
n
gradually diminish the infiltration capacity.
To avoid impairment of infiltration capacity the integrated concept
presented herein incorporates water quality wetland facilities. These
wetlands will be located on the golf course near the outlets of local storm
drain facilities. First -flush storm runoff and urban nuisance flow will be
removed from the drainage system and diverted to the water quality
wetlands for treatment. Water entering the wetlands will be consumed by
evapo - transpiration or will infiltrate into the ground after receiving the
benefits of wetlands treatment. A typical water quality wetland is shown on
Figure 4. Wetland operation and maintenance criteria are discussed in
Section VII.
Under this concept, pollutant -laden first -flush storm flows and urban
nuisance flows are removed from the drainage system and never enter the
infiltration facilities. During larger storms the relatively clean
post- first -flush storm runoff will by -pass the water quality wetlands and
n facilities. Without the first -flush pollutants these
proceed to the infiltration p
08/25/93 -16-
infiltration testing procedure was developed to evaluate the various
elements of the proposed sand filter concept.
G. Water Quality Considerations
The long -term performance of the infiltration system is influenced by the
quality of the storm water. If sediment -laden storm water is allowed to
enter the infiltration system the sediments will accumulate in the filter and
gradually diminish the infiltration capacity.
To avoid impairment of infiltration capacity the integrated concept
presented herein incorporates water quality wetland facilities. These
wetlands will be located on the golf course near the outlets of local storm
drain facilities. First -flush storm runoff and urban nuisance flow will be
removed from the drainage system and diverted to the water quality
wetlands for treatment. Water entering the wetlands will be consumed by
evapo - transpiration or will infiltrate into the ground after receiving the
benefits of wetlands treatment. A typical water quality wetland is shown on
Figure 4. Wetland operation and maintenance criteria are discussed in
Section VII.
Under this concept, pollutant -laden first -flush storm flows and urban
nuisance flows are removed from the drainage system and never enter the
infiltration facilities. During larger storms the relatively clean
post- first -flush storm runoff will by -pass the water quality wetlands and
n facilities. Without the first -flush pollutants these
proceed to the infiltration p
08/25/93 -16-
I flows can be accommodated by the infiltration facilities. Monitoring and
maintenance criteria are presented in Section VII.
+ When the off -site watershed is fully developed its sediment production rate
will be lower than it is now due to stabilization of the watershed and the
implementation of water quality best management practices. In its existing
condition, however, its surface soil is extremely erodible and sediment
production is relatively high. The acceptance of this sediment -laden water
into the Sierra Lakes water quality wetlands would result in a rapid
accumulation of sediment, and the need for frequent cleanout. Since
M�
sediment removal requires removal of wetland vegetation, it is desirable to
{ i_
minimize the frequency of cleanout. For this reason, until the off -site
k ;
watershed is stabilized by development, a temporary or interim off -site
debris control facility will be needed. This facility will be located
01 immediately adjacent to and upstream of Summit Avenue. Since this land
is not currently owned by Lewis Homes, it has been assumed that the
necessary rights can be acquired.
1
1 08/25/93 -17-
III. FIELD INFILTRATION TEST SETUP
This section describes the test facility which was constructed for the field
infiltration tests described herein, the water delivery and metering system, the
operational criteria and the general filling and testing approach.
P g g g pp
A. Test Pit Location
The location of the test pit which was used to conduct the various tests is
in the vicinity of fairway I, as shown on Figure 2. This site was chosen
because of its proximity to the source of water used to conduct the tests.
B. Water Delivery and Metering
The source of water used in conducting the tests was an on -site well
located approximately 600 feet from the test pit. A pump was placed in
the well approximately 400 feet below the surface. The water table is
approximately 300 feet below the surface.
The pump discharge line was fitted with both 3 -inch and 6 -inch flow
meters. These two meters were necessary to accurately monitor flow to the
1
08/25/93 -18-
test pit (Photograph Nos. 1, 2, and 3). Both meters were equipped with
totalizer dials to record the total volume of water delivered to the test pit.
The 3 -inch water meter was used to record the inflow to the pit for steady
state flow conditions. The accuracy of this meter was approximately plus
or minus 5 gallons per minute. Both the 3 -inch and 6 -inch meters were
used to determine the flow delivered to the test pit during initial filling.
1
08/25/93 -18-
1 C. Steady State Flow Conditions
Steady state flow conditions have been defined for purposes of this test as a
condition where the level in the pit does not change by more than 1 /100th
of a foot over a one -hour period. One hour hold times were used at each
test elevation level. After maintaining a constant water level for the one
hour period, the inflow rate into the pit was recorded as the steady state
infiltration rate at that p
h t articular water level. It should be noted that a
steady state flow condition is further assured by the time required to fill the
test pit. Prior to testing, it took approximately 8 hours to fill and maintain
a full pit condition.
OR
D. Meter Verification
In order to check the accuracy of the meter readings, the total number of
gallons delivered to the pit was also recorded from the 3 -inch meter
totalizer dials. The total number of gallons delivered to the pit over the
one hour time period was used to compute of the total gallons per minute
inflow. This computed inflow rate was compared with the actual meter
needle readings. In addition to this check, the time for the water level to
drop between test levels was recorded and the approximate infiltration rate
was computed based on the estimated volume in the pit between test levels.
E. Test Pit Filling
Because of the volume of the test pit, it was necessary to begin filling the
pit between 10:00 p.m. and 11:00 p.m. in order to assure that the pit would
be filled in time to begin testing at daylight. Erosion control provisions
g g P
were placed in the bottom of the test pit, when testing the various
08/25/93 -19-
[I
elements, to assure that the subgrade soils and /or the other elements of the
test pit configuration would not be eroded by the high flow rates used to
fill the pit.
F. Test Sequence
The tests were conducted by filling the pit, reaching a steady state flow
condition, documenting water level, time, and flow rate, and then allowing
the water level in the pit to drop. At eac h water level increment the steady
state flow condition was re- established and the water level, time, and flow
L
rate were documented.
[I
IV. FIELD INFILTRATION TEST PROGRAM
A. Test Programs
The following test programs were performed to evaluate the various
elements of the infiltration concept.
■ Test Program No. 1: determine infiltration rate of the subgrade soil
as a function of head.
■ Test Program No. 2: determine the infiltration rate of the subgrade
soils, the gravel, and the filter fabric as a function of head.
■ Test Program No. 3: determine the infiltration rate of the subgrade
soils, the gravel, the filter fabric, and the sand filter overlying the
filter fabric as a function of head.
■ Test Program No. 4: determine the effect of various levels of
siltation on the infiltration rate of the sand filter.
■ Test Program No. 5: determine the effect on infiltration rate
recovery by removing contaminated layers of the sand filter and
replacing them with clean sand.
■ Test Program No. 6: determine the infiltration rate of golf course
turf placed over 30 inches of native soil materials as a function of
head.
B. Test Program No. 1
1. Test Pit Configuration
The configuration for Test Program No. 1 is shown on Figure 6.
The pit was excavated approximately 11 feet deep by approximately
25 -foot square at the base. The pit side slopes were excavated
08/25/93 -21-
approximately 1.25 horizontal to 1 vertical. Two layers of 10 mil
visqueen were placed around the side slopes to assure that all the
percolated water passed through the base of the pit. A 2 -inch by
12 -inch timber frame was constructed on the floor of the pit to
insure a 25 -foot square infiltration area. In an effort to reduce
seepage around and under the visqueen liner, the visqueen liner was
extended approximately 6 to 8 inches creating a cutoff below the
bottom of the pit. The effect of creating this additional cutoff of
the visqueen liner resulted in a net effective infiltration area
dimension of approximately 27 -feet by 27 -feet. In the center of the
PR
pit, a 10 -foot staff gauge was installed. This staff gauge was a
conventional survey rod graduated in 1 /100 -foot increments
(See Photograph Nos. 4, 5, 6, and 7).
2. Results of Test Program No.l
The test results from Program No. 1 are shown on Figure 7. The
figure shows that infiltration rate increases with head. For example,
the infiltration rates at water levels of 4 feet and 6 feet were
approximately 12 feet per day and 32 feet per day respectively. At a
water depth of 9.6 feet, the infiltration rate is 59 feet per day.
3. Investigation of Edge Conditions
At the conclusion of Test Program No. 1, the visqueen was removed
from the northwest corner of the test pit to investigate the extent of
seepage behind the visqueen liner. A trench approximately 3 feet
wide by 5 feet deep was excavated (See Photograph No. 8).
08/25/93
-22-
Inspection of the wetted soil in the trench walls showed the water
rose outside the visquedn to a level 5.5 feet above the bottom of the
pit. Using this data point to establish the water surface elevation
outside of the visqueen, the flownet shown on Figure 8 was
constructed. Calculations were performed to estimate the affect of
lateral seepage near the edges of the pit on the infiltration rates.
The flownet and the resulting calculations indicate that the flow
around and underneath the visqueen liner is greater than the flow
near the center of the pit. The flownet findings are valuable in
identifying the most efficient configuration for infiltration facilities.
This subject is discussed further in the next section.
C. Test Program No. 2
1. Test Pit Configuration
The configuration for Test Program No. 2 is shown on Figure 9.
For Program No. 2 an 18 -inch thick gravel layer with particle sizes
from 1.5 inches to 2 inches was placed directly on the subgrade soils
and covered with a filter fabric. The fabric used in the test was
Mirafi MON, a nonwoven material. Sandbags were placed on top of
the fabric to secure it in position during filling of the pit. No other
changes were made to the configuration used for Test Program No.
1 (See Photograph Nos. 9, 10, 11, and 12).
k�
08/25/93 -23-
The results of Test Program No. 2 are shown on Figure 10. Figure
go 10 shows that placement of the gravel layer and filter fabric resulted
in a reduction of infiltration rate. The reduction ranges from
approximately 15 feet per day at a water depth of 9.6 feet to
approximately 4 feet per day at a water depth of 4 feet.
This reduction is believed to be caused by the placement of the
gravel layer directly on the subgrade material. Where the fine
subgrade material works between the gravel particles, the porosity of
the mixed media is less than that of either material by itself. This
zone therefore becomes a restriction in the flow. For this reason it
is planned to use filter fabric between the subgrade material and the
gravel in the final design to prevent the mixing of different sized
particles.
D. Evaluation of Test Programs Nos. 1 and 2
1. Selection and Testing of Rapid Sand Filter Material
The results of Test Programs Nos. 1 and 2 were used to determine
the size of the sand filter which will overlay the gravel bed material
beneath it. As stated previously, the sand filter should have the
capacity to produce an infiltration rate of 2 gallons per minute per
square foot. A number of varying sand gradations were obtained
and tested in the lab to determine their flow characteristics. The
sands examined included washed concrete sand, No. 30 silica sand,
08/25/93
-24-
No. 20 silica sand, and No. 12 silica sand. A particle size analysis
was performed and the resulting gradation plotted on Figure 11.
The gradation plot shows that the washed concrete sand is a
relatively well graded material. As mentioned earlier in this report,
1 the most appropriate rapid sand filter material would be a material
that is relatively open graded with very few fines. The washed
concrete sand does not exhibit these characteristics. However, the
® silica sands begin to approach a relatively open graded material.
Based on the particle size analysis, the No. 12 silica sand was
selected as the material most likely to produce the desired flow rate
of 2 gallons per minute per square foot and be capable of filtering
I fine grained materials.
All of the above mentioned sands were subjected to flow tests at the
RMA Group laboratory facilities. The data obtained from these
tests were the material permeability and flow rate per square foot
1 for 0.5 foot of head loss. The laboratory flow test data of the No.
12 silica sand shown is on Figure 12. The tabulated data indicate
that the No. 12 silica sand has a permeability of approximately 0.36
feet per minute and exhibits a flow rate of 2.7 gallons per minute
per square foot resulting from 0.5 foot of head loss. The material is
relatively coarse and may exhibit a tendency to move finer grain
materials at a deeper depth through' the filter. The effect of silt
11
0 08/25/93 -25-
migration through the sand filter was examined during Test Program
No. 4.
it
2. Sizing of the Sand Filter
Using the results of Test Program No. 2 and the results of the
laboratory flow test data, the required sand filter area was
determined. A number of computations were made assuming
to
various dimensions for the sand filter. A sample computation
11111 assuming a 9 -foot square sand filter is shown on Figure 13. The
computations shown represent a trial and error procedure where the
ow
objective is to balance the sand filter inflow with the subgrade
inflow. For example, at a water level of 10 feet (6 feet of water on
the sand filter surface) the discharge flowing through the sand filter
using 1.8 gallons per minute per square foot generated 146 gallons
0.1 per minute. Based on the laboratory flow test data, the head loss
.• created by 1.8 gallons per minute per square foot is 1.67 feet. The
km
remaining head available to drive the water through the filter fabric
and the gravel layer and into the ground is 8.33 feet. Using the
results of Test Program No. 2 and entering the curve with 8.33 -foot
of available head, indicates that 0.196 gpm /ft or 143 gallons per
minute can he infiltrated through the subgrade soils. Comparing
143 gallons per minute through the subgrade with
.. 146 gallons per minute through the sand filter shows close
ON
agreement. This computational procedure was repeated for water
levels of 8, 6, and 5 feet giving infiltration rates of 105, 61, and
.. 08/25/93 -26-
st
41 gallons per minute, respectively. Based on these computations, a
sand filter dimension of 9 -foot square was determined as the
appropriate configuration for Test Program No. 3.
E. Test Program No. 3
11 1. Test Pit Configuration
The configuration for Test Program No. 3 is shown on Figure 14.
To construct the sand filter area required for Test Program No. 3, a
wei
9 -foot square frame was constructed on top of the filter fabric in the
center of the pit area used for Test Program No. 2. Backfill was
0
placed up against this frame and then raised using side slopes of
approximately 1.25 horizontal to 1 vertical. The visqueen previously
installed for Test Program Nos. 1 and 2 was left in place (See
Photograph No. 13). Two additional layers of 10 mil. visqueen were
0 also placed completely around the side slopes of the pit and down to
the bottom of the 9 -foot square frame to assure that the entire flow
passed through the 9 -foot square area. The staff gauge used in the
previous test programs remained in place for monitoring the test
water levels.
■w
An important consideration in constructing Test Program No. 3 was
the delivery of water to the test pit. When delivering water to the
ins
pit, the surface of the sand filter should not be disturbed or eroded.
If disturbance or erosion occurred, the sand filter thickness would
•
change, introducing uncertainty into the test results. In order to
m
•• 08/25/93 -27-
111
achieve a uniform, nonerosive delivery of water to the pit, a 6 -inch
perforated PVC pipe was installed around the perimeter of the pit
outside of the sand filter, but below the surface level of the sand
s " (Figure 14). The pipe was laid in a gravel pack with the
rR
perforations on the bottom of the pipe (See Photograph No. 14).
When the water was delivered to this PVC pipe at high flow rates,
r was dispersed b flowing u through the
energy p y g p ravel before g g
reaching the top surface of the sand. After installing the PVC pipe,
No. 12 silica sand was placed in the filter area and compacted (See
Photograph Nos. 15 and 16).
Two piezometer wells were installed on opposite sides of the pit to
determine the loss of head due to flow through the sand filter.
2. Results of Test Program No.3
The results of Test Program No. 3 are shown on Figure 15. As a
result of installing the sand filter, an additional reduction in
infiltration rate occurred. At the 9.6 -foot water level, the reduction
was approximately 7 feet per day. At the 8 -foot water level, the
reduction was approximately 5 feet per day, and at the 6 -foot water
level, it was approximately 2 feet per day, compared to Test
Program No. 2.
The infiltration rate curve computed from the lab tests is also shown
on Figure 15. The computed infiltration rate curve predicted a
greater loss of infiltration rate than actually occurred. This result
08/25/93 -28-
in the field, was not as large as measured in the laboratory.
The infiltration rate curve from the surface of the sand to almost 2
Pq feet above the surface shows a higher rate than was measured in
Test Programs Nos. 1 and 2. Infiltration rates of approximately 20
feet per day were measured in this depth range. In this range, the
change in head had almost no influence on the infiltration rate.
This apparent increase in infiltration rate can be explained as a
result of the difference in the capacity of the filter at this low water
depth to the capacity of the gravel layer beneath it. Flows are
restricted through the sand filter to a larger degree than they are in
the gravel layer beneath it. The greater capacity of the gravel layer
beneath the sand filter, in both storage volume and flow capability,
is essentially drawing the flow through the sand filter at a higher
rate than would occur if the sand filter had a greater capacity at this
low head.
F. Test Program No. 4
1. Test Pit Confieuration
The configuration for Test Program No. 4 is shown on Figure 16.
The configuration for Test Program No. 4 is identical to that used
for Test Program No. 3 with the exception that a layer of silt is
placed on the surface of the sand. The silt materials used for this
test were obtained from the Owl Rock Plant in Lytle Creek.
08/25/93
-29-
insufficient silt available on -site to economically produce the volume
of material needed to perform the tests. Therefore, silt materials
determined by the geotechnical consultants to closely represent the
actual silt materials on the site were obtained from the Owl Rock
Plant and used for testing purposes. The particle size analysis of the
silt indicated the percentage of material passing the No. 100 and
200 sieves was 92 and 76, respectively (see Appendix C).
Three levels of siltation were used in Test Program No. 4. For the
initial testing of the siltation effects, 1.5 inches of silt was applied to
the filter (Test 4A). The second application of silt included an
additional 1.5 inches of silt (Test 413), and finally, the third
application of silt included another 1.5 inches of silt (Test 4C) for a
total of 4.5 inches of silt (See Photograph Nos. 17 and 18).
2. Results of Test Program No. 4
The results of the individual silt tests are shown on Figure 17. This
Figure shows that a continuing reduction of infiltration rate occurred
due to siltation. The application of the first 1.5 inches of silt
IJ
D
J
1 08/25/93
created a reduction in infiltration rate of about 5 feet per day. The
addition of the second 1.5 inches of silt created an additional
reduction in infiltration rate of 4 feet per day, and the third 1.5
inches of silt resulted in a further reduction in infiltration rate of
approximately 1 foot per day. With a total silt application of 4.5
-30-
H'i
inches, the infiltration rate at the 9.6 water level (approximately 6
foot of depth on the sand filter) was approximately 30 feet per day.
With water at the 8 -foot and 6 -foot levels (4 -foot and 2 -foot depth
levels on the sand filter), infiltration rates of approximately 20 feet
per day and 10 feet per day of infiltration were measured,
in respectively.
At the completion of each individual test, drive samples were taken
through the sand filter at 6 inch increments (See Photograph Nos.
19 and 20). These samples were taken to the laboratory for particle
size analyses and flow tests. The percentage of the material
contained in the samples, passing the No. 200 sieve, is plotted on
Figure 18 (refer to Appendix Q. For each 6 -inch increment of
depth in the sand filter, the percentage of material passing the
No. 200 sieve is shown. For Test Program No. 4A, approximately
6 percent passing the No. 200 sieve was accumulated in the upper
6 inches. For Tests 4B and 4C, (3 and 4.5 inches of silt applied),
approximately 11 percent and 12 percent of the material passing the
08/25/93 -31-
No. 200 sieve was contained in the upper 6 inches, respectively. For
Test 4A, approximately 3 percent of the material passing the
No. 200 sieve was contained within the 6 to 12 -inch layer, and for
Tests 4B and 4C approximately 5 percent and 8 percent of material
passing the No. 200 sieve was contained in the second layer from
08/25/93 -31-
6 to 12 inches, respectively. As we go deeper into the sand filter, we
find a continuing drop in the percentage of material passing the
No. 200 sieve in the filter. From a depth of 18 to 30 inches within
the filter, we find that the percent of material passing the No. 200
sieve is approximately 1 percent, or essentially equivalent to the
original clean silica sand. It is concluded from the test plots that,
h tests conducted the migration for the three to ration of the silt materials did g
not progress much below a depth of 18 to 20 inches in the filter.
As the filter sand was removed from the test pit, the filter material
overlying the gravel layer was examined. This examination indicated
little or no fine material accumulated on the fabric itself further
verifying that the migration of silts did not progress to the complete
depth of the filter.
G. Test Program No. 5
1. Test Pit Configuration
The test configuration for Test Program No. 5 is shown on Figure
19. The configuration for Test Program No. 5 is identical to Test
Program No. 4. The contaminated upper layers of the sand filter
were removed and replaced with clean sand. During the removal
process, it was observed that the majority of the siltation occurred in
the upper 10 inches of the filter. Based on these observations, 10
inches were removed and replaced with clean silica sand (See
Photograph Nos. 21, 22, and 23).
C 1
08/25/93 -32-
e
c
2. Results of Test Program No. 5
The results of Test Program No. 5 are shown on Figure 20. Figure
20 shows that approximately 6 feet per day of the 10 feet per day of
infiltration rate reduction measured in Test Program No. 4C was
recovered. This result, combined with the laboratory particle size
analysis data, indicates that if an additional 8 inches of material had
been removed from the filter, almost full infiltration rate recovery
0
would have been obtained (Figure 18).
H. Test Program No. 6
1. Test Pit Configuration
The configuration of Test Program No. 6 is shown on Figure 21.
For this test program, all of the sand materials in the pit were
L
removed and replaced with native soils. The native soils were
tamped in place with a hand held compactor. A turf material
proposed to be used within the fairway areas was placed on the
native soils. No other changes were made for Test Program No. 6
�r relative to the configuration for Test Program No. 5 (See
Photograph Nos. 25, 26, and 27).
2. Results of Test Program No. 6
The results of Test Program No. 6 are shown on Figure 22. The
test results indicate a significantly smaller infiltration rate for turf
over the native soils, compared to the sand - gravel filter. The test
results indicate that, at the 10 -foot water level, approximately 10 feet
per day of infiltration could be expected. This infiltration rate is
08/25/93 -33-
relatively high when compared to existing water conservation
spreading grounds, but because the test did not address the long-
term accumulation of silts in the turf and soil zone, it is not planned
to take credit for infiltration through the turfed fairway areas in the
g Y
design of the flood control system. However, it should be kept in
mind that even with a relatively low infiltration rate, the large area
of turf within the fairways will infiltrate substantial amounts of water
over and above the design requirements.
V. DISCUSSION OF TEST PROGRAM RESULTS
A. Evaluation of Laboratory Flow Test Data and Piezometer Data
The laboratory test data for the No. 12 silica sand was used to compute the
'"' anticipated loss of head through the sand filter for different flow rates.
These computed losses were compared against the loss of head as
determined from the piezometers. These comparisons were made for Test
Program Nos. 3 4A 4B and 4C. The results of these comparisons are
C, g , P
shown in Table 2 below:
Table 2
Comparison of Computed (Laboratory) and Measured (Piezometers)
Loss of Head in Feet through the Sand Filter
L
Test
Program
Water Level
9.6
8.0
6.0
5.0
I Comp.
Meas.
Comp.
Meas.
Comp.
Meas.
Comp.
Meas.
3
1.67
N/A
1.20
0.50
0.88
0.60
0.87
0.75
4A
2.57
1.60
1.89
1.50
1.13
1.40
0.94
1.30
4B
2.85
3.00
1.65
2.85
1.14
2.90
0.53
3.05
4C
3.73
3.70
2.40
3.30
2.00
3.05
0.85
3.20
Comparing the results from Test Program No. 3 indicates fairly good
agreement for the 6 -foot and 5 -foot water levels (2 -foot and 1 -foot of depth
on the surface of the sand filter, respectively). At the higher water levels,
agreement between the computed and measured values was poor. Aside
from the obvious differences between laboratory and field conditions, the
poor comparisons at the higher levels may be due to the fact that the
08/25/93
-35-
laboratory tests were performed under low head conditions, i.e. 1 foot. For
the 6 -foot and 5 -foot water levels, the head on the filter is closer to the
laboratory conditions.
For Tests 4A, 413, and 4C, the laboratory test data was used to compute the
loss of head through each 6 -inch increment of depth through the sand filter
for each steady state flow condition. The computed losses through each
6 -inch increment were accumulated to determine the total loss of head
through the 30 -inch thick sand for each steady state condition. For Test
4A, the loss in piezometric head was reasonably close to the computed
values except for the 9.6 -foot water level. This result may have occurred
for the same reason as described above for the unsilted sand filter.
For Tests 4B and 4C, the loss in piezometric head agrees quite closely with
the computed losses for the 9.6 water level. For the 6- and 5 -foot testing
levels, the piezometric losses were significantly greater than the losses
computed from the laboratory data. The piezometric losses also do not
vary significantly with head. Figure 17 shows that the addition of the third
1.5 inches of silt (Test 4C) did not significantly further reduce the
infiltration rates recorded after the second application of silt (Test 4B).
Since the piezometric head loss for Test 4C is only slightly higher than for
Test 413, it appears consistent with measured infiltration rates (Figure 17).
It can be concluded that the computed loss of head through the sand filter
based on laboratory flow tests showed reasonably good agreement for the
08/25/93 -36-
lower operating heads for the clean and the marginally silted sand filter.
The effect of heavier siltation significantly increased the piezometric losses
which were not reflected in the computed losses, based on the laboratory
test data, for the water levels of 8 feet and lower.
B. Flownet Analyses
1. Flownet Construction
As mentioned previously, a trench was excavated at the northwest
corner of the test pit to examine the extent of seepage which
occurred beneath the visqueen liner. This inspection indicated moist
soils to a level of about 5.5 feet above the bottom of the test pit. It
is reasonable to conclude that this level of seepage occurred during
?" the highest testing level, or the 9.6 -foot level. This single data point,
representing a loss of head of approximately 4.1 feet (9.6 feet minus
5.5 feet) was used to sketch the flownet.
The flownet is shown on Figure 8. The flow lines are shown as solid
lines. The equipotential lines are shown as dashed lines. A total of
nine flow paths have been sketched. The net has been constructed
® assuming a two - dimensional flow condition exists, and that Darcy's
permeability coefficient, k, is a constant. It was also assumed that
the visqueen liner was an effective impermeable membrane. The
equipotential lines were constructed with equal loss of head of
a
1 foot. The intersection of the flow lines and the equipotential lines
were drawn perpendicular and a "square" configuration maintained
as much as possible.
2. Foownet Analyses
When the flownet is properly constructed, the flow through each
path will be the same. For the 9.6 -foot water level, the steady state
m r 9 m ft 729 square foot infiltration
flow was 225 gp o 0.30 gp / ( q
area). Assuming a 1 -foot wide strip of a length equal to one half of
�., the pit width (13.5 feet), the total flow through the strip is 4.17 gpm.
Since each flow path carries the same flow, the infiltration along the
13.5 -foot long strip can be determined on a per foot basis by scaling
a the length of the individual elements of the flownet.
Performing the analysis described above indicates that approximately
30 percent of the total infiltration occurs near the edge of the test
3
pit. This result suggests that the use of relatively long and narrow
sand /gravel filter and infiltration areas will be more efficient than
areas which are more square in configuration.
The proposed infiltration concept will not be constructed in the field
with visqueen lined side slopes. Therefore, the edge flow condition
described will not be as pronounced as in the test case. The
adjacent soils; however, will have significantly lower permeabilities
than the sand and gravel materials creating a flow condition similar
to that shown by the flownet diagram, but to a lesser degree.
08/25/93
-38-
C. Effective Infiltration Rates
The flownet analyses has indicated that, for the test pit configuration, the
flow beneath and laterally to the visqueen is a significant portion of the
total flow. Larger infiltration areas than were used in field tests will be
used within the golf course areas. The use of these larger areas will reduce
the proportion of the total flow which passes through the edges of the
infiltration area. This suggests that the average infiltration rates
determined from the field test be adjusted to reflect the more predominate
rates near the center of the pit which are not affected by the edge
conditions. To account for the edge effects, the flow net studies were used
to compute adjustment factors to be applied to the recommended design
infiltration rate curve (Section VI). These adjustment factors are to be
applied to all ordinates of the curve dependent upon the width of the
infiltration area. The following table indicates the required adjustment
- 0
factors:
Table 3
Adjustment Factors to be Applied to Infiltration Rate
Design Curve Ordinates for Varying Infiltration Area Widths
F'
0
H
u
08/25/93
Infiltration
Area Width, Feet
Adjustment Factor
to be Applied to Design
Curve Ordinates
27
1.00
30
0.96
60
0.79
120
0.71
180
0.68
240
0.66
-39-
D. Size Relationship of Sand Filter Area to Infiltration Area
The results of Test Program No. 3 indicated that the 9 -foot square sand
filter area produced a flow rate per square foot of 1.80 gpm /ft'. This
configuration represented a balanced condition where the flow delivered b
g P Y
the filter was equal to the infiltration capacity of the subgrade soils. For
the infiltration area of 729 ft', the sand filter was 11 percent of the
infiltration area.
-40-
For design purposes, the sand filter area should not be less than 11 percent
f the required infiltration area. The sand filter and infiltration areas
o q
should be relatively long and narrow.
B. Infiltration Rate Curve
1. Sand Filter Maintenance Criteria
The infiltration rate to be used for design of the infiltration system
must be related to the proposed filter maintenance criteria. It is
proposed that the criteria for filter maintenance be based on the
level of filter siltation which occurred as a result of Test Program
No. 4A. Figure 18 shows the level of silt materials passing the
No. 200 sieve which were found to be in the various levels of the
a
sand filter based on particle size analyses. It is proposed that the
filter maintenance criteria be as follows:
■ The sand filter materials be removed and washed or replaced
should materials passing the No. 200 sieve be found in
percentages exceeding those defined by curve No. 4A of
Figure 18 within any 6 -inch layer of the filter.
2. Recommended Infiltration Rate Curve
The infiltration rate curve, as determined from Test Program
No. 4A (Figure 17), should be used in Recharge Basin I for initial
sizing of infiltration areas on the fairway and for developing
08/25/93
-41-
stage - discharge curves for flood routing purposes. For ponding
levels above the 10 -foot water level (6 feet above the sand filter),
the infiltration rate shall be assumed a constant. The recommended
infiltration rate curve is shown on Figure 23. This curve must be
adjusted to reflect the proposed width of the infiltration area in
accordance with Table 3 in Section V of this report.
Infiltration rate curve 4A is site specific to recharge basin location I.
Individual infiltration rate curves will be developed for the other
recharge basin locations as identified on Figure 2. The curves for
the other locations will be based on testing to be conducted in the
future at these locations. It is intended that only the infiltration rate
of the subgrade soils be determined at the other recharge basin sites.
Since the effect of the gravel, the filter fabric, and the filter sand is
known, there is no need to repeat tests of these elements.
Layer Material Specifications
C. Sand Filter /Gravel
1. Gravel Later
The gravel layer shall be washed No. 2 gravel conforming to the
following gradation:
Sieve Size Percent Passing
2 100
1 1/2 90- 100
1 5 -40
3/4" 0- 15
3/8" 0- 15
08/25/93
-42-
The specified gravel is readily available at Owl Rock, Lytle Creek,
California.
2. Sand Filter
The sand filter material shall be washed No. 12 silica sand
conforming to the following gradation:
Sieve Size Percent Passiny,
No. 4 100
No. 8 96- 100
No. 16 5 -15
No. 30 0- 10
No. 50 0- 10
+,
No. 100 0-5
No. 200 0- 1
The No. 12 silica sand is readily available at Corona Industrial Sand,
�*
Corona, California.
�r
3. Filter Fabric
The filter fabric material shall be a nonwoven fabric, type 140N as
manufactured by Mirafi or equal. The permeability of the filter
fabric shall be equal or greater than 0.2 centimeter per second and
the water flow rate shall be 285 gpm per square foot or greater.
D. Safety Factor
The design infiltration rate safety factor is the ratio of the expected actual
infiltration rate to the recommended design infiltration rate. The various
factors which contribute to additional infiltration, but were not included in
the recommended design infiltration rate are the following:
08/25/93
-43-
1. Infiltration through the golf course turf.
reliina hydrology studies of Recharge Basin I, the
Based on the m
P rY
ponding area at the peak flood level covers an area of 6.9 acres. Of
this 6.9 acres, 5.6 acres is required for underground infiltration area.
Since h capacity of the sub grade soils in this 5.6 acre area is full
S ce t o p ty g y
utilized, no additional water can be infiltrated. However, the
acreage beyond the infiltration area, 1.3 acres, which is turfed, can
infiltrate additional storm runoff. At a depth of 9.6 feet, the turfed
j
infiltration rate is 9 feet per day (Figure 23). This rate of
infiltration is equivalent to 2.1 feet per day over the gravel
infiltration area of 5.6 acres. Including the turfed area will increase
the recommended design infiltration rates for the 10 -, 8 -, and 6 -foot
�
�
water levels as tabled below:
Change in
MM
Infiltration % Change
Water Level Rate, Ft /day in Desi_cn Rate
9.6 +2.1 +6.5
�r
8 +1.4 +5.6
6 +0.7 +4.8
9.0Q.3 = 2.1 + /day
5.6
Including the turfed areas of the fairways increases the design
infiltration rate by an average of 5.6 percent.
r
2. Effect of underground storage in the gravel layer and sand filter and
infiltration prior to ponding occurring on the sand filter surface.
0
A preliminary flood routing study was made to determine the effect
of utilizing the available underground storage within the gravel and
sand materials. The volume of materials was estimated based on the
required infiltration area of 5.6 acres and assuming 40 percent voids.
The inflow hydrograph volume was altered by removing the volume
within the leading edge of the hydrograph in the amount of the
underground storage volume plus the water volume which infiltrated
prior to filling all voids. By iterating the stage - discharge curve, an
infiltration rate was finally determined where routing the altered
hydrograph matched the results of routing the original hydrograph.
This study showed that the effect of the underground storage was
equivalent to an additional 2.3 feet per day of infiltration or an
increase of approximately 9 percent.
P" 3. The allocation of 50 percent of the difference between the
moderately silted (Test 4A) infiltration curve and the clean sand test
(Test Program No. 3) infiltration rate curve.
It is reasonable to assume that one half of the difference in available
infiltration capacity will be effective over the time period of gradual
siltation. This difference (between Test Program Nos. 3 and 4A) in
infiltration rates for the 10 -, 8 -, and 6 -foot water levels is tabled
below:
08/25/93 -45-
Change in
Infiltration % Change
Water Level Rate, Ft /day* in Desiizn Rate
9.6 2.5 7.5
8 1.5 10.0
6 3.0 20.3
* Determined from Figure 17
Using 50 percent of the siltation loss results in an average increase
in the design infiltration rate of 12.6 percent.
4. Effect of 1.5 feet of ponding depth above o e t h e peak 100-year flood
level in the recharge basins.
It is proposed to establish the overflow elevations of the escape
routes at the downstream limits of recharge basins at 1.5 feet above
the peak 100 -year flood levels. The effect of this additional
surcharge storage was determined by flood routing. The
recommended design infiltration curve ordinates (Figure 23) were
reduced until the peak flood level rose 1.5 feet. The results of this
have be
analysis indicated that the design curve ordinates would to
reduced 46 percent to create a 1.5 -foot rise in the peak flood level.
This represents an additional safety factor of 46 percent or 16.3 feet
per day of infiltration rate at the peak flood level.
08/25/93
-46-
IL
5. The effect of increased infiltration rates for water depths above 6
1 feet.
The recommended design infiltration rate curve (Figure 23)
indicates a constant infiltration rate of 35.5 feet per day for water
depths above 6 feet., This recommendation was made since the
depth of water on the surface of the sand filter did not exceed 6 feet
during infiltration testing. The test results indicate, however, that
there is a clear, nearly linear trend indicating a continuing increase
in infiltration rates with water depth. To evaluate the effect of this
'
increased infiltration capacity, the slope of the infiltration rate curve
was extrapolated as the average slope between the vertical and the
slope of the curve between the 6- and 10 -foot ordinates. This
revised curve was used as the
stage - discharge relationship for a routing study where the effect of
'
peak flood level using the extrapolated curve.
reducing the curve ordinates on the peak flood level was examined.
'
This study indicated that to create a 1.5 -foot rise in the water
surface elevation within the excess storage area, the design curve
ordinates would have to be reduced by 56 percent. This represents
an additional safety factor of 56 percent or 22 feet per day at the
'
peak flood level using the extrapolated curve.
Combining the effects of all five factors will increase the design infiltration
rate by 5.6+9+12.6+46+56 = 129.2 percent representing a factor of safety
of 2.3.
08/25/93 -47-
It should be noted that a substantial additional factor of safety is inherent
in the flood surcharge storage volume available in all recharge basins from
the peak 100 -year flood level to the finish floor elevations of the adjacent
residences.
E. Possible Failure Modes and Mitigation
All flood control and drainage systems are designed to meet defined
regional and nationally accepted standards for capacity and performance.
When the storm events exceed the accepted standard, overflow or other
modes of "failure" can be expected.
In this case, an infiltration system is being used to manage flood flows.
The flood water is being diverted to the soil. The system must maintain its
integrity during extreme storms and possible damage to property must be
minimized. The following lists the possible modes of failure of the
infiltration concept and methods built into the plan to reduce the problems
of possible failure to insignificance.
Problem: Sand filters do not perform as well as the clean filters used in the
field test.
Solution:
a. Design the system to discount the filter capacity by using for filter
capacity the infiltration rate for the filter after the application of
1.5 inches of silt. This is a 13 percent reduction compared to the
new filter condition. This will result in an increase in total area
08/25/93 -48-
required for the sand filter elements. Operation and maintenance
criteria are set to maintain at least this capacity.
b. The monitoring program will assume that the filters are at "design
capacity." Golf course fairway infiltration rates of up to 10 feet per
Y
day will supplement sand filter infiltration rates but have not been
included in the design capacity.
C. The other factors discussed in Paragraph D above also significantly
supplement infiltration rates but have not been included in the
design capacity.
Problem: A storm occurs which is more severe or of longer duration than the
SBCTFCD 100 year multi -day storm, which was used for design.
Solution:
a. The golf course fairway basins will be designed to collectively hold
the 100 -year multi -day storm volume less the infiltration volume,
and will include 3 foot of freeboard.
facilities that
b. An escape route will be designed in the to assure
should the basins fill to 1.5 foot above their design elevation, they
will start to discharge over a durable aesthetically attractive
"spillway" swale. This escape route system will be incorporated into
all inter -basin conveyances within the golf course. This will assure
no loss of stored storm water due to embankment failures. At the
southern boundary of the property, the overflow during these rare.
2
events will be directed into one or more streets at low velocities and
aligned directly downstream.
r J
L
08/25/93 -50-
VII.
OPERATION AND MAINTENANCE REQUIREMENTS
The concept of managing storm flows by allowing ponded storm water to infiltrate
within a golf course is feasible from a hydrologic standpoint, as demonstrated
h in In the field success of the conee t relies on consistent ear -in ear -out
r
herein. p Y ,y
performance of the drainage and flood flow delivery system, the quality of the
flows to be infiltrated, and the condition of the sand filter infiltration facilities.
All three of these must be monitored, maintained, and operated to assure they are
always in good working condition so that Sierra Lakes and the downstream
community are protected from floods and receive the planned water quality and
water conservation benefits.
L
The operation and maintenance program has three elements:
�1
■ Delivery
system;
■ Water quality facilities; and
■ Sand filter infiltration facilities.
A. Delivery System
1. Off -Site Flood Flows
Off -site flows approach the Sierra Lakes project from the north.
They will be collected in reinforced concrete pipe or box storm
drains and brought under Summit Avenue to the Sierra Lakes
project site. These collection facilities will be constructed by Lewis
Homes as art of the regional flood controls stem. Within the site,
p g Y
the off -site flows will be carried in storm drains and golf course
swales to the golf course sand filter infiltration facilities. They will
08/25/93
-51-
VW
also be carried from upstream fairway basins to downstream basins
to efficiently distribute the water throughout the system.
Distribution of flood flows within Sierra Lakes is a critical aspect of
the system. The reinforced concrete facilities and surface swales
that are currently proposed to transmit flood flows are shown on
Figure 24. These are major flood control facilities and must be
inspected, operated, and maintained as such.
All the systems identified on Figure 24 are to be inspected each year
between September 1 and September 15 to assure that they are
clean, free of obstructions, structurally sound, and ready for the
upcoming storm season. The inspection report to be filled out by
the inspector is attached as Appendix F. The inspection will be
conducted by the SBCTFCD. The inspection report will be signed
�* by the inspector and a copy provided to the Fontana City Engineer.
i
6W
Any work required to bring the facilities up to designed conditions
will be accomplished by the SBCTFCD prior to October 15.
2. On -Site Flood Flows
On -site drainage and flood control facilities will normally be
reinforced concrete facilities or durable drainage swales used to
transport storm runoff from the in -tract drainage systems to the
water quality wetlands and sand filter infiltration facilities within the
golf course. These facilities, the in -tract drainage systems, and all
catch basins will be visually inspected annually between September 1
„�, 08/25/93 -52-
practicable due to pipe size diameters, T.V. inspections will be
conducted every three years. These inspections will be conducted by
the SBCTFCD using he inspection report in Appendix F. The
� P P PP
inspection report will be signed by the inspector and a copy provided
to the Fontana City Engineer.
F
B. Water Quality Facilities
1. Description and Purpose of Proposed Facilities
The water quality wetlands are essential elements of the sand filter
infiltration system and also further the goals of the NPDES water
quality program. The wetlands will resemble the voluntary wetlands
seen throughout the area at storm drain outlets.
The water quality wetlands will be located near the outlets of the
flood control and storm drain systems (Figure 24). They will remove
urban nuisance flows from the storm drains. They will have more
than enough capacity to handle nuisance flows.
Nuisance flows occur throughout the year as a result of lawn
watering, car washing, and the like. Nuisance flows carry some
urban pollutants which will be removed or reduced in the water
quality wetlands. The nuisance flows will nourish the wetland
vegetation. Any water in excess of plant evapo- transpiration
requirements will infiltrate or evaporate.
08/25/93 -53-
�i
iv j �
First -flush storm flows which carry a large percentage of the storm
water -borne pollutants from roofs, parking lots, streets, etc. will also
be directed into the water quality wetlands.
The water quality wetlands are designed to accommodate the runoff
from a first -flush storm event. The inlets to the wetlands are
designed so that when the wetland has received the first -flush and is
filled to the design capacity, further inflow cannot occur. The
relatively clean post- first -flush water by- passes the diversion
structure and continues to the golf course fairways and the sand
filter infiltration facilities.
!a The purpose of the water quality wetlands is to collect and treat
L
urban nuisance and first -flush flows. This process removes from the
d golf course sand filter infiltration facilities these flows and their
attendant fine sediment, trash, litter, and other materials that would
�r
tend to reduce the infiltration rates. In addition, by consuming the
+ nuisance flows, the wetlands will prevent the delivery of nutrients to
the infiltration facilities, reducing the risk of algae growth. The
growth of algae in sand filters is undesirable because it obstructs the
pores in the sand and reduces the infiltration rate.
There are two major mechanisms at work in these wetlands. The
first is the removal of sediments by settling. Many urban runoff
pollutants attach themselves to sediment particles. When the
08/25/93 -54-
and plant materials are removed and disposed of in an approved
disposal site.
2. Objective of the Operation and Maintenance Prop-ram
The objectives of the operation and maintenance program are:
■ To protect the water quality in the North Fontana area by
monitoring removal of pollutants in the wetlands and
maintaining the facilities in effective operating condition.
■ To assure the initial establishment of the vegetation and to
stabilize its operation.
• To prepare a comprehensive Field Operations Manual on the
operation, maintenance, and monitoring of the wetlands.
• To maintain the plants in the water quality wetlands in a
healthy, robust condition for optimum pollutant removal.
• To assure that routine maintenance requirements are
identified and sediment removal activities are conducted in a
timely manner to prevent any undesirable pollutant
accumulation in the sediment.
-55-
sediments settle to the bottom the pollutants go with them. Other
pollutants are dissolved in the runoff. Some of the dissolved
pollutants are taken up by the wetland plants. These pollutants are
retained in the ant tissues. When pollutant levels in the bottom
P
sediments and plant tissues reach prescribed values, the sediments
and plant materials are removed and disposed of in an approved
disposal site.
2. Objective of the Operation and Maintenance Prop-ram
The objectives of the operation and maintenance program are:
■ To protect the water quality in the North Fontana area by
monitoring removal of pollutants in the wetlands and
maintaining the facilities in effective operating condition.
■ To assure the initial establishment of the vegetation and to
stabilize its operation.
• To prepare a comprehensive Field Operations Manual on the
operation, maintenance, and monitoring of the wetlands.
• To maintain the plants in the water quality wetlands in a
healthy, robust condition for optimum pollutant removal.
• To assure that routine maintenance requirements are
identified and sediment removal activities are conducted in a
timely manner to prevent any undesirable pollutant
accumulation in the sediment.
-55-
The wetlands will be supervised by golf course personnel to
discourage trespass and vandalism. One of the routine
inspection and maintenance activities will be to check security
and perform routine cleanup and housekeeping. Also, the
wetlands will be checked for insect or nuisance problems and
corrective action initiated if necessary.
b. Sediment removal and plant harvest
Accumulated sediment volume will be monitored to assure
that adequate water storage capacity is available. Sediment
configuration will be monitored to assure that first - flush,
nuisance flows, and supplemental irrigation water are well
distributed among the plants. Pollutant concentrations in the
08/25/93 -56-
■ To assure that plant harvesting activities are undertaken in a
timely manner to remove the accumulated pollutants from the
wetlands.
■ To maintain conditions which minimize nuisances to
neighboring residences.
3. Maintenance Philosophy
The aintenance philosophy will be based on the concept of regular
e p PY P �
monitoring to evaluate wetland conditions against established
standards, followed, when necessary, by operation or maintenance
routines to restore conditions to the established standard.
4. Maintenance Proeram Elements
a. Security and housekeeping
The wetlands will be supervised by golf course personnel to
discourage trespass and vandalism. One of the routine
inspection and maintenance activities will be to check security
and perform routine cleanup and housekeeping. Also, the
wetlands will be checked for insect or nuisance problems and
corrective action initiated if necessary.
b. Sediment removal and plant harvest
Accumulated sediment volume will be monitored to assure
that adequate water storage capacity is available. Sediment
configuration will be monitored to assure that first - flush,
nuisance flows, and supplemental irrigation water are well
distributed among the plants. Pollutant concentrations in the
08/25/93 -56-
sediment will be monitored so that sediment removals may be
scheduled before unacceptable concentrations are reached.
Plant materials will be monitored to assure that plant harvests
and cleanouts are scheduled before excessive plant materials
accumulate or pollutant concentrations in the plants reach
undesirable levels.
The wetlands will be designed so a portion of the area can
be sectioned off for drainage and maintenance without
disturbing the remainder. Every five to ten years, as
indicated by the monitoring, a section of wetland can be
isolated, drained, and cleared of sediment and excess plant
LW materials. The cleanouts will be scheduled during the
summer, when the remaining undisturbed wetlands can fully
accommodate the nuisance flow. The re- establishment of
P
plants in the cleaned area will be facilitated by transplanting
of plants from the other wetland areas.
�4
J
The removed materials will be disposed of in an approved
manner. <Experience has indicated that the materials will be
r.
® suitable for disposal in a sanitary landfill. The monitoring
program is specifically designed to allow the scheduling of
cleanouts before pollutants reach unacceptable levels.
HI
C. Readiness, repair, and restoration
The wetlands and appurtenances will be located at the outlets
of the in -tract drainage systems. They will be subject to
occasional storm flows. Berms and embankments may be
subject to burrowing by animals. The annual maintenance
cycle will provide for repairs and rehabilitation to be
scheduled for the summer months so the facilities will be in
good working order prior to each rainy season.
5. Interim Operation of the Wetland Facilities
Upon completion of construction and planting of the facilities, Lewis
Homes will engage a wetland specialist familiar with the facilities to
operate, maintain, and monitor them on an interim basis until the
following conditions have been met:
i� ■ The facilities have operated through two storm seasons.
■ The Field Operations Manual has been completed and
approved by SBCTFCD.
■ The Criteria for Plant Establishment presented below have
been met.
The purpose of this interim operation period of not less than two
years is to assure that the wetland plants are well established and
that operational procedures have stabilized and have been
documented in the Field Operations Manual prior to turning the
facilities over to the SBCTFCD. Criteria for plant establishment
08/25/93
-58-
and operational stability are presented below. The Field Operations
Manual is described in the following Section.
a. Criteria for plant establishment
The wetland plants will be considered to be established when
they reach the following conditions:
■ Plant coverage of 90 percent of the bottom of the
wetland area maintained for one year.
b. Criteria for operational stability
The facilities will be considered to have reached operational
stability when the following conditions are achieved:
■ At least two winter rainy seasons have been
experienced, with documentation of water levels and
durations in the wetland. The reaction of the wetland
plants to the storm inflow (storm damage, plant vigor,
pollutant impact) will be documented. Sediment
deposits, erosion, and storm damage at any of the
facilities will be documented and repaired as required.
C. Responsibilities of Wetland Specialist
As each of the wetlands is developed, the establishment
program described below will be implemented. For the first
three months, a monitoring/maintenance visit by a wetland
specialist will be conducted every two weeks. Thereafter, for
the remainder of the period, the visits will be conducted
monthly.
08/25/93
-59-
?M
L
■ Check security.
■ Pick up trash.
1. Monitoring/maintenance visit tasks
The following tasks will be performed during each
monitoring/maintenance visit.
in
�
■ Measure and record growth of selected plants.
■ Estimate and record plant cover.
■ Observe and document plant health, stress,
disease, or pests.
■ Inspect and activate irrigation system to check
effectiveness and adjust if necessary.
■ Inspect inflow distribution system and clear if
necessary.
?M
L
■ Check security.
■ Pick up trash.
■ Collect sediment sample if scheduled.
■ Check for storm damage, vandalism, animal
burrows.
in
■ If water is ponded wetland, record staff gage
elevation, check clarity, color, and odor.
■ Check for insect infestations.
"Wetland
■ Fill out and sign Monitoring and
Inspection Form" (Appendix G).
2. Plant replacement
The wetland specialist will be responsible for seeing
that dead and damaged plants are removed and
08/25/93
-60-
concentrations will be monitored every year and
recorded. This record will be examined every spring
08/25/93 -61-
replaced monthly during the first three months and
annually during late fall for the remainder of the
interim period.
3. Maintenance
The wetland specialist will be responsible for normal
"
maintenance routines. Additional visits will be
required for storm sampling, re air and preparedness
g P P P
work.
About April 15 each year the wetlands and
appurtenant facilities will be reviewed for storm
damage and wear. A work list will be prepared for
W
execution during the summer. Maintenance crews will
be scheduled during the summer to accomplish the
work.
L
About October 15 each year the facilities will be
for
reviewed to assure they are in good condition the
winter storm season. Again, all components will be
inspected. Any uncompleted work will be finished and
any new damage will be repaired.
Sediment accumulations and sediment pollutant
concentrations will be monitored every year and
recorded. This record will be examined every spring
08/25/93 -61-
0
0 and used to predict the likely date for a sediment
cleanout.
6. Preparation of the Wetland Field Operations Manual
Each wetland facility has its own characteristics, some of which
emerge only after the growth cycle is under way. The identification
the management response that has proven to be most effective, the
wetland specialist can assemble a Field Operations Manual that will
allow experienced public works maintenance personnel to
successfully perform this work.
Preparation of the Field Operations Manual is the last of a series of
P+
6 W activities in the planning and establishment of a wetland, marking
the transition from wetland development to routine operation.
It is intended that the Field Operations Manual stand alone as a
training guide for future wetland operating personnel. Recognizing
that there will be turnover in assigned staff, the manual will contain
of individual wetland characteristics and responses to stimuli and the
prescription appropriate rescri tion of a ro riate management responses is very important
and requires the services of an experienced wetland specialist. By
PR
documenting the conditions that arise in a particular wetland and
the management response that has proven to be most effective, the
wetland specialist can assemble a Field Operations Manual that will
allow experienced public works maintenance personnel to
successfully perform this work.
Preparation of the Field Operations Manual is the last of a series of
P+
6 W activities in the planning and establishment of a wetland, marking
the transition from wetland development to routine operation.
It is intended that the Field Operations Manual stand alone as a
training guide for future wetland operating personnel. Recognizing
that there will be turnover in assigned staff, the manual will contain
background information on the Sierra Lakes project, existing_ and
potential future drainage water quality problems, and the objectives
and elements of integrated flood control -water conservation -water
quality management system.
08/25/93
-62-
summary of the areas, capacities, and other engineering information
about the facility.
It will contain a brief description of the water - cleansing process that
takes place in a wetland, to provide a context in which to explain the
operation, maintenance, and monitoring requirements. It will
contain a brief description of the build -up of pollutants in plant
tissue and sediment and the need for monitoring and periodic
removal of these materials.
It will describe the soil moisture sensors in the wetland and explain
how to use them to determine the need for supplemental irrigation.
It will contain locations and descriptions of the water quality
monitoring stations, the sampling criteria, and instructions on
obtaining water samples for analysis.
It will contain an operation, maintenance, and monitoring schedule
and task list, and an inspection form.
It will contain the acceptable standards for housekeeping, security,
and maintenance of the facilities, and the procedures which have
proven to be effective and efficient for correcting unsatisfactory
conditions. A list of the necessary tools, equipment, manpower, and
supplies, along with an estimate of the time required, will be
included.
It will contain the name and telephone number of the appropriate
Ps
persons to call in the event of emergency or unusual conditions.
L
It will contain descriptions of any insect or plant pests that were
observed during the establishment period and the techniques that
were effective in dealing with them.
7. Wetland Monitoring
All wetlands will be monitored monthly to check for housekeeping
conditions, maintenance conditions, security, vandalism, and insect
infestations.
In addition, 2 wetlands will be selected to represent pollutant
accumulations from off -site and on -site drainage areas. These
levels in
wetlands will be sampled each spring to determine pollutant
the sediments and in the plant tissues.
C. Sand Filter Infiltration Facilities
The sand filter infiltration facilities will be located in the golf course
fairway areas. These areas will be graded to control the runoff from their
tributary areas for infiltration into the native alluvial material. The actual
infiltration areas will be elements of the golf course and will, therefore,
enjoy the benefits of professional management and daily supervision and
use.
08/25/93
-64-
The sand filter infiltration areas will normally only receive flows during
storms exceeding the first -flush storm. When this occurs, the early portion
of the hydrograph will carry fine sediments and most of the pollutants into
the water uali wetlands immediate) upstream. The water quality
q h' Y P q
wetlands will minimize the delivery of sediments and other material that
would reduce the filter effectiveness.
During major storm events, it can be expected that some sediment and
clogging materials will be washed onto the surface of the filters. Some will
enter the filter. In order to assure that adequate filter capacity is available
to safely and reliably infiltrate larger floods, a monitoring program is
required. The intent of the program is to alert the operators that remedial
work is required to return the filters to their required capacity, if necessary.
Based on the results of field tests previously described, economical testing
I procedures for the filter are presented below.
Figure 25 shows the locations for testing the sand filter infiltration areas.
The tests are to be conducted between September 1 and September 15
each year until it can be demonstrated that less frequent testing is prudent
and acceptable to the City of Fontana and SBCTFCD.
The tests will include obtaining drive samples of the filter at each location
shown. The samples will be taken in 6 -inch increments through the entire
30 -inch filter cross section. Particle size analyses will be performed for
each sample to determine the percent of material passing the No. 200 sieve
08/25/93
-65-
08/25/93 -66-
contained in each 6- inches of the filter. If any increment of the sand filter
contains material passing the No. 200 sieve exceeding the limits defined by
Test 4A as shown on Figure 18, the contaminated portion of the filter shall
be removed and either washed or replaced with new material. If the sand
material is washed, a minimum of three random samples of the washed
material shall be collected for a particle size analysis to assure that the
material meets the original material gradation specification. Any new
PR
material shall also be sampled and tested against the new material
gradation specifications.
L
If contamination is not found in all locations of the sand filter infiltration
area, only the contaminated areas need be restored to the as -built
condition subject to the approval of the SBCTFCD.
w
08/25/93 -66-
VIII.
RESPONSIBILITY FOR OPERATION, MAINTENANCE, AND MONITORING
Responsibility for operation and maintenance of the infiltration and water quality
system is conveniently separated into its three components; the flood water and
storm drain delivery system, the water quality wetlands, and the sand filter
infiltration facilities.
A. Flood Control and Storm Drain Delivery Systems
The flood control and storm drain systems are traditional facilities that are
e
designed and constructed by developers using plans approved by the
responsible agencies. For the Sierra Lakes project, it is expected that the
plans and specifications for these facilities will be prepared by Lewis
Homes. They will be reviewed and approved by the City of Fontana and
the SBCTFCD.
As these facilities are constructed, they will be dedicated to SBCTFCD for
operation and maintenance. The SBCTFCD will be provided sufficient
rights -of -way to allow for the operation and maintenance of surface and
underground facilities that are necessary for the successful performance of
the system.
B. Water Quality Wetlands
The water quality wetlands will be designed and constructed by Lewis
Homes using plans and specifications approved by the City of Fontana and
the SBCTFCD. To assure the successful development of the wetland
facilities into the Sierra Lakes project and provide for their satisfactory
long -term performance, it will be necessary to:
08/25/93 -67-
■ Oversee initial planting and start -up, and
■ Develop a Field Operations Manual based on the first two years
experience.
To accomplish the above requirements, the following operation and
maintenance responsibilities will be adopted.
1. From Construction to 2 Years Later
All wetlands will be owned and operated by Lewis Homes. During
this period, they will be planted, irrigated, and maintained by Lewis
Homes. The experiences gained during this two -year period will
allow the development of the Field Operations Manual. This
Manual will describe the detailed operation, maintenance,
monitoring, and reporting requirements for the complex of water
quality wetlands. A more detailed description of the content of the
Manual is contained in Section VII of this report.
2. After Two Years
At the end of the two -year period, following completion of
construction of the wetlands, they will be turned over to the
SBCTFCD for operation, maintenance, monitoring, and reporting as
a regional NPDES facility. The Field Operations Manual,
explaining the recommended policies and procedures, will be
provided to the SBCTFCD. This Manual will describe the role of
the golf course operator in performing routine irrigation and
08/25/93 -68-
maintenance of the wetlands. Monitoring, reporting, and wetland
renewal will be accomplished by the SBCTFCD. During the period
when Lewis Homes operates and maintains the water quality
wetlands, it will perform the water quality monitoring and wetland
management practices described in Section VII.
C. Sand Filter Infiltration Facilities
The sand filter infiltration facilities are integral portions of the golf course.
The surface of these facilities will be maintained by the golf course
operator. The monitoring of the filters through the particle size analyses
described in Section VII will be conducted by a certified soils laboratory in
the presence of an inspector or engineer representing the SBCTFCD.
Removal and replacement of filter material shall be done at the request of
the SBCTFCD by the golf course operator in the presence of an inspector
from the SBCTFCD. Should the golf course operator not comply with the
SBCTFCD request for remedial work, the District shall, using its rights -of-
way, perform the remedial work itself and assess the golf course owner.
Records of all operation, maintenance, monitoring, and reporting shall be
maintained by the SBCTFCD with copies provided to the City of Fontana
and the Regional Water Quality Control Board.
J
l
0
1 08/25/93 -69-
AGENCIES
A development of a regional flood control and water quality facility involves not
only the land developer but a number of government agencies. The following
describes the responsibility of each.
A. Lewis Homes
Lewis Homes is the landowner and developer. As such, it will arrange for
the design and phased construction of the flood control, drainage, water
quality, and infiltration systems as part of its development for housing and
commercial properties and a golf course. Lewis Homes will own and
operate each phase of each facility until they are dedicated, or by
agreement, transferred to another entity as described below:
1. Reinforced concrete boxes and channels to convey storm water in
Summit Drive and downstream to the infiltration facilities -
transferred to the SBCTFCD with adequate rights -of -way.
2. Surface swales for flood overflow within the golf course - transferred
I" to golf course owner /operator with adequate rights -of -way to the
16
golf course owner /operator and the SBCTFCD. In the event the
golf course owner /operator fails to perform, the SBCTFCD will
H__�
'1
r
08/25/93
assume operation and maintenance responsibilities and assess the
golf course owner /operator to recover its costs.
3. Local in -tract storm drains - transferred to the SBCTFCD with
adequate rights -of -way.
-70-
Field Operations Manual - transfer to the SBCTFCD for operation
and maintenance as a regional element of the NPDES program with
adequate rights -of -way Lewis Homes will maintain underlying rights
to adjust or otherwise modify the wetlands as required for proper
golf course management, provided such modifications are consistent
with the NPDES program. Aesthetic maintenance of the wetlands
will be performed by the golf course owner /operator with adequate
rights -of -way.
5. Sand filter infiltration facilities- transferred for surface operation
L and aesthetic maintenance and sand filter remedial work by the golf
P" course owner /operator with adequate rights -of -way. The SBCTFCD
will be provided with adequate rights and rights -of -way to assure the
proper operation, maintenance, and routine filter remedial work is
accomplished by the golf course owner /operator per SBCTFCD
requirements.
6. Spillway hardware; spillway, swales, etc. - transferred to golf course
owner /operator. The SBCTFCD will be provided adequate rights
and rights -of -way to assure proper maintenance and repair.
B. City of Fontana
The City of Fontana is responsible for approval of the Sierra Lakes project
including the flood control drainage facilities. Additionally, under its role
as a co- ermittee with the SBCTFCD the City will be r for the
p � h' P
implementation of storm water runoff quality controls.
08/25/93 -71-
The City will review and approve the flood control and drainage facilities
and the complex of NPDES Best Management Practices (BMPs), which
include the water quality wetlands and the sand filter infiltration system
within the golf course. The City may choose to transfer the entire flood
control system and the water quality facilities to the regional drainage
, agency which is the SBCTFCD for operation and maintenance as part of its
i
regional system.
err
If the City retains any of the facilities for operation and maintenance, it
will be responsible for their monitoring, inspection, and operation and
maintenance.
C. San Bernardino County Transportation /Flood Control District
1 0
k The Lewis Homes proposal to develop a comprehensive regional plan for
flood control, water conservation, and water quality management will have
a significant affect on related regional responsibilities of the SBCTFCD.
The groundwater recharge system, as proposed by Lewis Homes, will
a probably be implemented in other areas in the North Fontana area. This
type of regional planning will alter the flood management and water quality
requirements of downstream systems. It is proposed that the SBCTFCD
will accept the Lewis Homes facilities as part of its flood control and water
quality master plan. Once accepted, it is understood that it would accept
the transfer of the facilities for operation and maintenance from the City.
For this to happen, the District would need pre - approval of the concept
and the plans and specifications.
C ; 08/25/93 -72-
A
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n
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L
L
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L
D. Golf Course Owner /Operator
The golf course owner /operator will perform a number of very important
functions related to this flood control and water quality management
proposal.
Due to the owner /operator's continuous presence in the management and
operation of the golf course, he will be responsible for the prevention of
unauthorized access to the golf course, the wetlands, and the recharge
basins during storm times.
The owner /operator will maintain the water quality wetlands and the
surface of the rapid sand filter infiltration areas and will be responsible to
respond to the SBCTFCD requirements for remedial work such as
replacement of filter material if required.
In summary, the golf course owner /operator will:
■ Maintain security and prevent trespass of golf course areas,
particularly during storm periods;
■ Provide aesthetic maintenance of the water quality wetlands and the
rapid sand filters;
■ Perform remedial work as required for sand filters and other
drainage related facilities within the golf course areas; and
■ Cooperate with the City and SBCTFCD concerning monitoring or
maintenance of all flood control and /or water quality facilities.
08/25/93 -73-
X. LIABILITY
The liability accepted by each of the firms and public agencies involved in the
planning, design, approval process, and construction of the sand filter infiltration
system is summarized as follows:
Project Engineer - Errors and Omissions liability related to the planning and design
�. of the facilities.
Lewis Homes - responsibility for the construction per the approved plans and
specifications.
Golf Course Owner /Operator - responsible for any trespass or use of the golf course
year -round including during times of ponding in recharge basin areas of the golf
course and during times when ponded areas exist in the water quality wetlands.
Also responsible for aesthetic aspects of all facilities within the golf course.
rr+
Dior
City of Fontana - responsible for the effect of its approval of plans and
specifications and for operation and maintenance of any facilities it accepts.
�r. SBCTFCD - responsible for the effect of its approval of plans and specifications
and for operation and maintenance of any facilities it accepts.
H
u
E
XI.
PHASING OF CONSTRUCTION
Lewis Homes recognizes that this proposal to create a regional flood control and
6,
P"
water quality system, using sand filter infiltration facilities and wetlands, will take
between 1 and 3 years to obtain the necessary permits and construct. During this
time period, it will be necessary to phase the construction of these facilities to
meet the following objectives:
s
6
1. There will not be any increase in flood peaks downstream of the Sierra
04
Lakes project.
2. Interim BMPs will be used to prevent the degradation of surface runoff
water quality.
In addition, it will be necessary to develop a phasing plan for the development of
any temporary or permanent facilities required upstream or downstream of the
Sierra Lakes property. Sierra Lakes will prepare and receive approval from the
City of Fontana and the SBCTFCD of a phasing plan for the construction of the
flood control and water quality management facilities that will be up- dated, if
IP
necessary, every six months.
08/25/93
-75-
Fl�
XII. FINANCING OF CONSTRUCTION AND OPERATION, MAINTENANCE,
, MONITORING, AND REPORTING
The construction, operation, and maintenance of flood control and water quality
facilities that affect numerous properties are clearly regional in impact. As such,
it is reasonable that the beneficiaries share the cost of the planning design,
construction, and operation /maintenance of the facilities. It is common to
establish Area Drainage Plan (ADP) fee systems to finance the construction of the
facilities. Often a Benefit Assessment sub -zone or other mechanism is used to
raise the required operation and maintenance funds.
The ADP fees are charged to each developer in the "benefiting area" as they
develop. The Benefit Assessment is typically levied on each residential or
commercial unit in the benefiting area.
The Lewis Homes proposal represents a major link in the regional flood control
and water quality chain. The flood control, water conservation, and water quality
benefits of the integrated concept extend far downstream. It is appropriate that
the concept presented herein, once approved by the City of Fontana, be expanded
to maximize its benefits throughout the North Fontana region. It is also
appropriate that the City of Fontana act to establish the regional financial
framework of ADPs and Benefit Assessments or equivalent financing so that
Lewis Homes may recover that portion of its costs attributable to regional benefits
for other lands.
XIII. FIGURES
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1 08/25/93 -77-
San Gabriel Mountains
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Avenue
P
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Walnut U ¢ Avenue
CITY OF
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Proposed Freeway
TAKEN FROM: SIERRA LAKES SPECIFIC PLAN
PREPARED BY TURRINI & BRINK
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CITY OF
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Proposed Freeway
TAKEN FROM: SIERRA LAKES SPECIFIC PLAN
PREPARED BY TURRINI & BRINK
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INFILTRATION TEST RESULTS
DEPTH VS. RATE OF INFILTRATION
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INFILTRATION RATE ( G.PM PER SQUARE FOOT)
SIERRA LAKES DATE
�®® 8 -93
.H.•4..� INFILTRATION TEST RESULTS
DEPTH VS, RATE OF INFILTRATION FIGURE
JOMPI MTETTEMER& ASSOCIATES LM
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INFILTRATION RATE ( G.PJA PER SQUARE FOOT)
SIERRA LAKES DATE
INFILTRATION TEST RESULTS 8 -93
DEPTH VS. RATE OF INFILTRATION FIGURE
M EM@t &A550CWT61LTG TEST PROGRAM NOS. 3 AND 6 22
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VILLAGE
A.C.
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PA. M PA. is PA. ,U
8103MERS PARK -=-L,.-Cxzr
91 AC .5fAll
911 AC 14.1 AC
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LEGEND 1
OFF-SITE DRAINAGE COLLECTOR CONDUITS
ON-SITE IN-TRACT DRAINAGE CONDUIT WITH
WATER QUALITY WETLAND AT OUTLET
TEMPORARY DEBRIS CONTROL FACILITY
TAKEN FROM: SIERRA LAKES SPECIFIC PLAN
PREPARED BY TURRINI & BRINK
SIERRA LAKES DATE
PROPOSED OFF-SITE AND
❑ NTS ON-SITE FIGUR
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SAND FILTER SAMPUNG LOCATIONS (TYPICAL)
TYPICAL SAND FILTER
WASTE AREAS
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PLAN VIEW
N.T.S.
SIERRA LAKES DATE
8-93
' TYPICAL RAPID SAND FILTER FIGURE
v e JOMMKTErreMM&A560CLVMLa TESTING LOCATIONS
rtorneerymo Mquwenerrr ftmiumo 25
5151 Airway Avenue, Suite Q -1 Costa Mesa, CaKornia 92626
XIV. PHOTOGRAPHS
08/25/93 -78-
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GALLONS _
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Photograph No. 1: 3 -inch flow meter with totalizer dials. I Photograph No. 2: 3 -inch and 6 -inch flow meters plumbed into
lid 6 -inch discharge line.
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Photograph No. 3: 6 -inch pump discharge
line from pump to test pit.
DATE
SIERRA LAKES 8
• � PHOTOGRAPHS OF FLOW METERS
JoMnMTETT ,,LTD AND TRANSMISSION LINE PAGE
E 1h fKGIfiEERtNG MAMAIifMEfiT PLAf41OE1G
M51 Airway Avenue, Suite Q -1 Costa Me•,a California 92626
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Photograph No. 4: Test Program No. 1, placing of visqueen liner. '' ,i i r- Photograph No. 7: Test Program No. 1, near completion of Test
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: ,,,,< � z , �_ - Photogr No. 6: Test Program No. 1, testing in progress. ,,
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• Photograph No. 8: Test Program No. 1, examining side slope for
Photograph No. 5: Test Program No. 1, completed test pit. seepage after completion of Test No. 1.
DATE
SIERRA LAKES 8 -93
1..
TEST PROGRAM NO. 1 PAGE 1
JOHN M T£fTEMER & A550CAT1 LTD
-_ - - - ' ' ElIGINWJ1G MAtIAG MCf1T PLAfIMIriG 2
3151 Airway Avenue, Suite Q - Costa Mesa California 92626
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Photograph No. 9: Test Program No. 2, material used for 18 -inch Photograph No. 11: Test Program No. 2, beginning of testing.
thick gravel layer.
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Photograph No. 10: Test Program No. 2, placing 18 -inch thick Photograph No. 12: Test Program No. 2, near completion of
gravel layer. Test No. 2.
SIERRA LAKES DATE
�` TEST PROGRAM NO. 2 8 -93
PAGE
\ -- _ -/ JOPtn Fl T1 TTemER & ASSOCIATES. LTD
e NGlne[fUMC1 MAIACeMeMT PIAnnUf1G 3
5151 Airway Avenue. Suite Q1 Costa Meta. California 92626
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Photograph No. 13: Test Program No. 3, placing backfill Photograph No. 15: Test Program No. 3, placing No. 12 silica
adjacent to 9 -foot square sand filter frame.
‘11151literlenlitaR,711ri 1
sand filter material.
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Photograph No. 14: Test Program No. 3, installing 6 -inch Photograph No. 16: Test Program No. 3, near completion of
perforated PVC pipe. Test No. 3
i J SIERRA LAKES DATE
8 -93
- /$•�. TEST PROGRAM NO. 3 PAGE
Bonn ft Ttrrt d MEM P T �T�
c rxsineei r,o r-wt rnenr P 4
3151 Airway Avenue, Suite Q-1 Costa Mesa California 92626
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Photograph No. 17: Test Program No. 4, completed test pit with Photograph No. 19: Test Program No. 4, taking 6 -inch drive
1.5 inches of silt over silica sand (Test 4A). samples of sand filter after Test 4A.
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Photograph No. 18: Test Program No. 4, near completion of Photograph No. 20: Test Program No. 4, backfilling drive
Test 4A. sample locations.
DATE
SIERRA LAKES 8 _93
TEST PROGRAM NO. 4 PAGE
\--_-____/ JOt41 Mt TETrEt96i & A550CJATt 5 LTD
`_" Etoiri eEUnG M/VIACEMEF1T PlAnn,ri( 5
3151 A+rway Avenue • Suite Q -1 Costa Mesa California 92625
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Photograph No. 21: Test Program No. 5, removing silted silica
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Photograph No. 23: Test Program No. 5, replacing silted silica
filter sand.
sand with clean material.
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Photograph No. 22: Test Program No. 5, close -up of silted silica
sand filter showing clean sand at 8 -inch to 10 -inch depth.
1
DATE
SIERRA LAKES 1
8 -93
TEST PROGRAM NO. 5 PAGE
y JOHN M TETTEMER & A55OC ATES LTD
ENGINEERING rw1A6tMrNT PIAr t1Ir1G 6
M51 Airway Avenue. Suite Q -1 Costa Me<_a California 92626
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Photograph No. 24: Test Program No. 6, placing native material Photograph No. 26: Test Program No. 6, completed test pit.
backfill prior to placing turf.
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Photograph No. 25: Test Program No. 6, completing placement Photograph No. 27: Test Program No. 6, testing in progress.
of native soils prior to placing turf.
DATE
SIERRA LAKES 8 -93
'�'�` TEST PROGRAM NO. 6
- = PAGE
J0111 et TETTEMER & A550CWT6. L11:1 -- H70inetNn6 MMN6fMtM PLN4N11Q 7
5151 Airway Avenue, Suite Q-1 Costa Mesa. CM forma 92626