FINAL
Construction Site Best Management Practices
(BMP) Manual
CTSW-RT-24-425.11.1
March 2024
California Department of Transportation
Division of Environmental Analysis, Storm Water Program 1120 N Street
Sacramento, California 95814
http://www.dot.ca.gov/hg/env/stormwater/index.htm
Caltrans Technical Report Documentation Page
1. Report No.: CTSW-RT-24-425.11.1
2. Type of Report: Guidance Manual
3. Title and Subtitle: Construction Site Best
Management Practices (BMP) Manual
4. Report Date: March 2024
5. Copyright Owner(s): California Department of Transportation
6. Caltrans Project Coordinator(s): Andrew Bui
7. Performing Organization Names and Addresses:
Brown and Caldwell
201 N. Civic Drive, Suite 300,
Walnut Creek, CA 94596-3864
8. Contract No.: 43A0425
9. Task Order No.: 11
10. Sponsoring Agency Name and Address:
California Department of Transportation
Division of Environmental Analysis
Stormwater Program MS-27
1120 N Street
Sacramento, CA 95814
www.dot.ca.gov/hq/env/stormwater/inde
x.htm
11.Caltrans Functional Reviewer(s): Andrew Bui, Arthur Hedayati, Mel Ghiglieri Mohammad Hajeer, Charlow Arzadon,
Travis Deem
12. Supplementary Notes:
13. External Reviewer(s):
14. Key Words: stormwater, guidance, manual, BMPs,
installation, maintenance SWPPP, WPCP
15. Distribution Statement:
16. No. of pages: 272
17. Abstract: The Manual presents guidance for
California Department of Transportation
(Caltrans) staff, Consultants, and
Contractors to use to determine
applicability of Best Management
Practices for implementation in
construction projects.
DISCLAIMER
Any statements expressed in these materials are those of the individual authors and do not necessarily represent the views of CALTRANS, which takes no responsibility for any statement made herein. CALTRANS has not independently verified the results, conclusions or claims presented herein.
No reference made in this publication to any specific method, product, process, or service constitutes or implies an endorsement, recommendation, or warranty thereof by CALTRANS.
The materials are for general information only and do not represent a finding of fact, standard of CALTRANS, nor are they intended as a reference in purchase specifications, contracts, regulations, statutes, or any other legal document. CALTRANS makes no representation or warranty of any kind, whether expressed or implied, concerning the accuracy, completeness, suitability, or utility of any information, apparatus, product, or process discussed in this publication, and assumes no liability therefore. This information should not be used without first securing competent advice with respect to its suitability for any general or specific application.
Anyone utilizing this information assumes all liability arising from such use, including but not limited to infringement of any patent or patents.
Technical Memoranda are used for timely documentation and communication of preliminary results, interim reports, or more localized or special purpose information that may not have received formal outside peer reviews or detailed editing.
Software applications are provided by CALTRANS “as is” and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall CALTRANS be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and on any theory of liability, whether in contract, strict liability, or tort (including negligence or otherwise) arising in any way out of the use of this software, even if advised of the possibility of such damage.
Copyright (2024) California Department of Transportation All Rights Reserved
NOTICE
This document has been checked for ADA compliance using built in checkers in Microsoft Word and Adobe Acrobat Pro.
Accessibility Assistance: Caltrans makes every attempt to ensure our documents are accessible. Due to variances between assistive technologies, there may be portions of this document which are not accessible. Where documents cannot be made accessible, we are committed to providing alternative access to the content. Should you need additional assistance, please contact us at (916) 654-2852 and/or (916) 956-6187 Voice, or dial 711 to use a relay service or visit https://dot.ca.gov/request-ada-compliant-documents. iii
Table of Contents
List of Tables ................................................................................................................................................ v List of Figures ............................................................................................................................................... v List of Abbreviations ................................................................................................................................... vi
1. Introduction .........................................................................................................................................1-1
1.1 Overview ...................................................................................................................................1-1
1.2 Regulations and Stormwater Permits .....................................................................................1-2
1.2.1 Federal Regulations ...................................................................................................1-2
1.2.2 Caltrans NPDES Statewide Permit and NPDES Construction General Permit .......1-2
1.2.3 Other NPDES Permits ................................................................................................1-4
1.3 Caltrans Stormwater Manuals and Websites .........................................................................1-5
2. Caltrans Construction Stormwater Management Program Requirements .....................................2-1
2.1 Stormwater Pollution Prevention Plan and Water Pollution Control Program ......................2-1
2.2 Construction BMP Applicability ...............................................................................................2-2
2.3 Minimum Construction BMPs ..................................................................................................2-5
2.3.1 Surface Water Buffers ...............................................................................................2-7
2.4 BMP Inspection Frequency ......................................................................................................2-7
3. Temporary Soil Stabilization BMP .....................................................................................................3-1
3.1 Temporary Soil Stabilization ....................................................................................................3-1
3.1.1 SS-1 Scheduling .........................................................................................................3-2
3.1.2 SS-2 Preservation of Existing Vegetation .................................................................3-5
3.1.3 SS-3 Temporary Hydraulic Mulch ..............................................................................3-9
3.1.4 SS-4 Temporary Hydroseed .................................................................................... 3-12
3.1.5 SS-5 Temporary Soil Binder ................................................................................... 3-15
3.1.6 SS-6 Temporary Tacked Straw ............................................................................... 3-21
3.1.7 SS-7 Temporary Cover and Rolled Erosion Control Products (RECP) .................. 3-24
3.1.8 SS-8 Temporary Mulch ........................................................................................... 3-33
3.2 Temporary Concentrated Flow Conveyance Controls ......................................................... 3-36
3.2.1 SS-9 Earth Dikes/Drainage Swales & Lined Ditches ............................................ 3-37
3.2.2 SS-10 Outlet Protection/Velocity Dissipation Devices ......................................... 3-42
3.2.3 SS-11 Slope Drains ................................................................................................. 3-44
3.2.4 SS-12 Streambank Stabilization ............................................................................ 3-46
4. Temporary Sediment Control BMP ....................................................................................................4-1
4.1 Temporary Sediment Controls .................................................................................................4-1
4.1.1 SC-1 Temporary Silt Fence ........................................................................................4-2
4.1.2 SC-2 Sediment/Desilting Basin.................................................................................4-8
4.1.3 SC-3 Sediment Trap/Curb Cutback ....................................................................... 4-17
4.1.4 SC-4 Temporary Check Dam .................................................................................. 4-20
4.1.5 SC-5 Temporary Fiber Rolls .................................................................................... 4-24 Construction Site Best Management Practices (BMP) Manual Table of Contents iv
4.1.6 SC-6 Temporary Gravel Bag Berm/Earthen Berm ................................................ 4-30
4.1.7 SC-7 Street Sweeping ............................................................................................. 4-33
4.1.8 SC-8 Sandbag Barrier ............................................................................................. 4-35
4.1.9 SC-9 Temporary Straw Bale Barrier ....................................................................... 4-38
4.1.10 SC-10 Temporary Drainage Inlet Protection .......................................................... 4-42
4.1.11 SC-11 Temporary Compost Sock ........................................................................... 4-51
4.1.12 SC-12 Flexible Sediment Barrier ............................................................................ 4-56
5. Wind Erosion Control BMP .................................................................................................................5-1
5.1 Wind Erosion Control ...............................................................................................................5-1
5.1.1 WE-1 Wind Erosion Control........................................................................................5-2
6. Tracking Control BMP .........................................................................................................................6-1
6.1 Tracking Control .......................................................................................................................6-1
6.1.1 TC-1 Temporary Construction Entrance ....................................................................6-2
6.1.2 TC-2 Temporary Construction Roadway....................................................................6-6
6.1.3 TC-3 Entrance/Outlet Tire Wash ............................................................................ 6-11
7. Non-Stormwater Management BMP .................................................................................................7-1
7.1 Non-Stormwater Management ................................................................................................7-1
7.1.1 NS-1 Water Conservation Practices ..........................................................................7-2
7.1.2 NS-2 Dewatering ........................................................................................................7-4
7.1.3 NS-3 Paving, Sealing, Saw Cutting, Grooving, and Grinding Activities ...................7-7
7.1.4 NS-4 Temporary Stream Crossing .......................................................................... 7-11
7.1.5 NS-5 Clear Water Diversion .................................................................................... 7-15
7.1.6 NS-6 Illegal Connection and Illicit Discharge Detection and Reporting .............. 7-27
7.1.7 NS-7 Potable Water/Irrigation ................................................................................ 7-30
7.1.8 NS-8 Vehicle and Equipment Cleaning .................................................................. 7-32
7.1.9 NS-9 Vehicle and Equipment Fueling .................................................................... 7-34
7.1.10 NS-10 Vehicle and Equipment Maintenance ........................................................ 7-36
7.1.11 NS-11 Pile Driving ................................................................................................... 7-38
7.1.12 NS-12 Concrete Curing ........................................................................................... 7-40
7.1.13 NS-13 Material and Equipment Use Over Water .................................................. 7-42
7.1.14 NS-14 Concrete Finishing ....................................................................................... 7-44
7.1.15 NS-15 Structure Removal Over or Adjacent to Water ........................................... 7-46
8. Waste Management and Materials Pollution Control BMPs ...........................................................8-1
8.1 Waste Management and Materials Pollution Control ............................................................8-1
8.1.1 Waste Management BMPs ........................................................................................8-1
8.1.2 Materials Pollution Control BMPs .............................................................................8-1
8.1.3 WM-1 Material Delivery and Storage ........................................................................8-2
8.1.4 WM-2 Material Management ....................................................................................8-5
8.1.5 WM-3 Stockpile Management ...................................................................................8-8
8.1.6 WM-4 Spill Prevention and Control ........................................................................ 8-11
8.1.7 WM-5 Solid Waste Management ........................................................................... 8-15
8.1.8 WM-6 Hazardous Waste Management .................................................................. 8-18 Construction Site Best Management Practices (BMP) Manual Table of Contents v
8.1.9 WM-7 Contaminated Soil Management ................................................................ 8-22
8.1.10 WM-8 Concrete Residuals and Washout Wastes ................................................. 8-26
8.1.11 WM-9 Sanitary and Septic Waste Management ................................................... 8-31
8.1.12 WM-10 Liquid Waste Management ....................................................................... 8-33
9. TMDL Implementation Requirements ...............................................................................................9-1
9.1 Introduction ..............................................................................................................................9-1
9.2 Waste Load Allocations ...........................................................................................................9-1
9.2.1 Additional TMDL Requirements ................................................................................9-2
10. Post-construction Treatment BMPs ...................................................................................... 10-1
10.1 Regulatory Environment ....................................................................................................... 10-1
10.2 List of Approved TBMPs ........................................................................................................ 10-1
10.3 Construction Implementation Checklist .............................................................................. 10-2
10.4 TBMP Maintenance Indicators ............................................................................................. 10-4 Appendix A: Definition of Terms .................................................................................................................. A Appendix B: Selection of Temporary Soil Stabilization Controls ............................................................... B Appendix C: Active Treatment Systems ...................................................................................................... C List of Tables
Table 1-1. Relevant Caltrans Stormwater Documents, Manuals, and their Purpose 1 ........................1-5 Table 1-2. Stormwater-Related Websites ................................................................................................1-6 Table 2-1. Construction Site BMPs ..........................................................................................................2-5 Table 2-2. Monitoring Requirements for CGP .........................................................................................2-8 Table 2-3. Monitoring Requirements for LTCGP .....................................................................................2-9 Table 3-1. Temporary Soil Stabilization BMPs ..................................................................................... 3-36 Table 4-1. Temporary Sediment Control BMPs .......................................................................................4-1 Table 5-1. Wind Erosion Control BMPs ....................................................................................................5-1 Table 6-1. Tracking Control BMPs ............................................................................................................6-1 Table 7-1. Non-Stormwater Management BMPs ....................................................................................7-1 Table 8-1. Waste Management and Materials Pollution Control BMPs ................................................8-1 Table 10-1. Approved TBMPs ................................................................................................................ 10-1 List of Figures
Figure 1-1. Map of California with Regional Water Quality Control Boards and Caltrans Districts .....1-3 Figure 2-1. Construction Site BMP Applicability Flowchart ....................................................................2-4 Construction Site Best Management Practices (BMP) Manual Table of Contents vi
List of Abbreviations
AC Asphalt Concrete
ATS Active Treatment System
BMP Best Management Practice
Caltrans State of California, Department of
Transportation
CCS Cellular Confinement System
CFR Code of Federal Regulations
CGP Construction General Permit
COI Change of Information
CSBMP Construction Site Best Management
Practices
CWA Clean Water Act
DSA Disturbed Soil Area
DWQ Division of Water Quality
EA Expenditure Authorization
EPA Environmental Protection Agency
H:V horizontal versus vertical
lb/ac pound(s) per acre
LTCGP Lake Tahoe Hydrologic Unit Construction
General Permit
MMBN Middle-Mile Broadband Network
MS4 Municipal Separate Storm Sewer
System
NONA Notice of Non-Applicability
NOT Notice of Termination
NPDES National Pollutant Discharge Elimination
System
PID Project Initiation Document
PPDG Project Planning and Design Guide
PSE Plans, Specifications, and Estimate
QPE Qualifying Precipitation Event
QSD Qualified SWPPP Developer
QSP Qualified SWPPP Practitioner
RE Resident Engineer
REAP Rain Event Action Plan
RECP Rolled Erosion Control Products
RUSLE2 Revised Universal Soil Loss Equation v2
RW Receiving Water
RWQCB Regional Water Quality Control Board
SMARTS Storm Water Multiple Application
Reporting and Tracking System
SS Settleable Solids
SWMP Stormwater Management Program
SWPPP Stormwater Pollution Prevention Plan
SWRCB State Water Resources Control Board
TBMP Treatment Best Management Practice
TMDL Total Maximum Daily Load
WLA Waste Load Allocation
WPC Water Pollution Control
WPCD Water Pollution Control Drawing
WPCP Water Pollution Control Program
1-1
Section 1
Introduction
1.1 Overview
This Construction Site Best Management Practices (CSBMP) Manual (Manual) provides guidance on the selection and implementation of Best Management Practices (BMP) into construction projects within the State of California, Department of Transportation (Caltrans) right-of-way.
The primary objective of this CSBMP Manual is to provide the overall process for selecting, installing, and maintaining temporary BMPs in Caltrans construction projects. The CSBMP Manual provides a general background of stormwater documents and references to other stormwater manuals, includes a flowchart showing applicable BMP triggers for each of the six Construction Site BMP categories, and detailed guidance for the selection, installation, and required maintenance for individual BMPs. The Manual ties into the Caltrans 2023 Standard Specifications applicable to BMP installation and maintenance frequency. If there is a conflict between this Manual and a Caltrans Standard Specification, either due to a Specification revision or modification, the Caltrans Standard Specifications will control.
This Manual is organized as follows:
• Section 1 – Introduction provides a background on regulations and stormwater permits, and relevant stormwater guidance documents and websites.
• Section 2 – Caltrans Construction Stormwater Program Requirements describes general documents prepared for or related to the construction phase of the project, instructions for selecting and implementing Construction Site BMPs, and details of the minimum BMP inspections required for construction sites.
• Section 3 – Temporary Soil Stabilization BMPs provides an overview of the Soil Stabilization BMP category and a listing and working details for Caltrans Construction Site BMPs for Temporary Soil Stabilization.
• Section 4 – Temporary Sediment Control BMPs provides an overview of the Sediment Control BMP category and a listing and working details for Caltrans Construction Site BMPs for Temporary Sediment Control.
• Section 5 – Wind Erosion Control BMPs provides an overview of the Wind Erosion BMP category and a listing and working details for Caltrans Construction Site BMPs for Wind Erosion Control. • Section 6 – Tracking Control BMPs provides an overview of the Tracking Control BMP category and a listing and working details for Caltrans Construction Site BMPs for Temporary Tracking Control.
• Section 7 – Non-stormwater Management BMPs provides an overview of the Non-stormwater Management BMP category and a listing and working details for Caltrans Construction Site BMPs for Non-stormwater Management.
• Section 8 – Waste Management and Material Pollution Control BMPs provides an overview of the Waste Management and Materials Pollution Control BMP category and a listing and working details for Caltrans Construction Site BMPs for Waste Management and Materials Pollution Control.
Construction Site Best Management Practices (BMP) Manual Section 1 1-2
• Appendix A – provides definitions of terms used throughout this Manual. • Appendix B – provides guidance on the selection of temporary soil stabilization controls. • Appendix C – provides guidance on the requirements for implementing an Active Treatment System (ATS) to comply with the Construction General Permit (CGP) or the Lake Tahoe Hydrologic Unit Construction General Permit (LTCGP).
1.2 Regulations and Stormwater Permits
1.2.1 Federal Regulations
The Clean Water Act (CWA) is a federal regulation that deals in part with controlling discharges of pollutants from Municipal Separate Storm Sewer Systems (MS4), construction sites, and industrial activities as part of the National Pollutant Discharge Elimination System (NPDES) permit process. In 1990, the Environmental Protection Agency (EPA) promulgated federal stormwater regulations requiring municipal, construction, and industrial stormwater discharges to comply with an NPDES permit.
In California, the EPA delegated its authority to issue NPDES permits to the State Water Resources Control Board (SWRCB). The SWRCB has nine regional water quality control boards across the State.
Figure 1-1 presents a depiction of the nine regional board boundaries in relation to the Caltrans Districts.
1.2.2 Caltrans NPDES Statewide Permit and NPDES Construction General Permit On July 15, 1999, the SWRCB issued the first NPDES Permit, Statewide Stormwater Permit and Waste Discharge Requirements for the State of California, Department of Transportation (NPDES No.
CAS000003) hereby called Caltrans Permit. The Caltrans Permit requires the preparation and implementation of the Caltrans Statewide Stormwater Management Plan (SWMP). The SWMP describes how Caltrans plans to implement the Caltrans Permit requirements and describes Caltrans’ program that addresses stormwater pollution control related to various activities, including planning, design, construction, maintenance, and operation of roadways and facilities.
The Caltrans Permit regulates stormwater discharges from Caltrans properties, facilities, and activities, and requires that the Caltrans’ construction program comply with the requirements of the NPDES General Permit, waste discharge requirements for Discharges of Stormwater Runoff Associated with Construction Activity (NPDES No. CAS000002) issued by the SWRCB and hereby called Construction General Permit or CGP.
Both the Caltrans Permit and the CGP have been reissued since 2009. The current Caltrans Permit Order 2022-0033-DWQ became effective January 1, 2023, and requires construction projects with 1 acre or more of soil disturbance to comply with the CGP Order WQ 2022-0057-DWQ and amendments thereto. There are a small number of Caltrans projects that are situated in the Lahontan Regional Board area (Lake Tahoe specifically); those projects are subject to the LTCGP Order No.R6T-2016-0010. The CGP and the LTCGP require that the authorized Stormwater Pollution Prevention Plan (SWPPP) and all other relevant documents and data for SWPPP projects be uploaded to the SWRCB’s Stormwater Multiple Application and Report Tracking System (SMARTS).
Construction Site Best Management Practices (BMP) Manual Section 1 1-3
Figure 1-1. Map of California with Regional Water Quality Control Boards and Caltrans Districts Construction Site Best Management Practices (BMP) Manual Section 1 1-4
1.2.3 Other NPDES Permits
There are other permits that might be applicable to Caltrans construction projects depending on the specific activities or regional requirements. Any construction project might trigger the Statewide Industrial Permit coverage if the project involves a proposed batch plant or other industrial activities, as outlined below. In addition, there are specific regional permits that might be applicable for projects that propose dewatering operations.
1.2.3.1 Industrial Permit
Industrial activities are not covered under the Caltrans Permit. The Statewide Permit for Stormwater Discharges Associated with Industrial Activities (i.e., the Industrial General Permit [IGP]) (Order 2014- 0057-DWQ) as amended in 2015 and 2018 regulates nine broad categories of industrial activities.
There are activities that might occur ancillary to construction projects; for those operations, the industrial permit is triggered. Caltrans contracts include language requiring the Contractor to implement BMPs and seek coverage as required under the IGP.
1.2.3.2 Dewatering Permit
Dewatering discharge requirements vary among the nine regional boards. Caltrans has developed a Dewatering Manual that should be referred to in order to determine appropriate requirements for the individual construction site. The Dewatering Manual can be accessed via the website link included in Table 1-2.
This Manual reflects permit language up to its publication date. Any permit renewals subsequent to the publish date of this Manual, will dictate the latest requirements.
Construction Site Best Management Practices (BMP) Manual Section 1 1-5
1.3 Caltrans Stormwater Manuals and Websites
Caltrans has devised a comprehensive stormwater program to comply with Caltrans Permit requirements. In addition to the SWMP, Caltrans has developed several stormwater guidance manuals that are available on their website for staff, consultants, and anyone in the public to use to implement appropriate BMPs.
Table 1-1 presents a list of the primary reference material to be used for determining applicable permit requirements and specific compliance mechanisms developed by Caltrans. This Manual is intended to be used in conjunction with the SWPPP/Water Pollution Control Program (WPCP) Preparation Manual as both are directly related to water pollution control when performing construction operations within Caltrans projects and rights of way.
Table 1-1. Relevant Caltrans Stormwater Documents, Manuals, and their Purpose 1 Document Purpose
Caltrans Stormwater Management
Plan (SWMP)
Describes how Caltrans plans to implement the Caltrans Permit requirements. The SWMP describes the Caltrans’ program and addresses stormwater pollution control related to various activities, including planning, design, construction, maintenance, and operation of roadways and facilities.
Stormwater Quality Handbooks:
Project Planning and Design Guide
(PPDG)
Guides project planning staff in preparing and selecting appropriate Best Management Practices, BMPs, for inclusion into Contract Plans. Includes step-by-step guidance for documenting the selection and implementation of BMPs.
Appendix E - Stormwater Data Report
(SWDR)
Document prepared by the Project Engineer or Landscape Architect that formsthe basis for ensuring compliance with the Caltrans Permit requirements for the Design Division. Determination of SWPPP/WPCP applicability based on disturbed soil area and BMP line items included as part of the Contract Plans.
Stormwater Pollution Prevention Plan
(SWPPP) and Water Pollution Control
Program (WPCP) Preparation Manual
Guides Contractors and Caltrans staff through the process of preparing a SWPPP and WPCP. This manual provides detailed step-by-step procedures, instructions, sample text, and a template that Contractors must use to prepare the SWPPP/WPCP. Templates conform to CGP requirements based on risk level; LTCGP requirements, including deviations from CGP language; and Caltrans requirements for preparing WPCPs.
Construction Site Monitoring Program
Guidance Manual
This manual presents guidance for Caltrans staff and Contractors to use in planning and implementation of stormwater monitoring programs at construction sites. Describes and provides guidance on developing sampling and analysis plans, standard operating procedures for pH and turbidity sampling, and other requirements of the CGP and LTCGP.
Guidance for Temporary Soil
Stabilization
This document guidesthe planning, selection, and implementation of Caltrans temporary soil stabilization BMPs.
Field Guide to Construction Site
Dewatering
This dewatering guide informs and guides intended users in selecting, implementing, and monitoring construction site dewatering operations.
Erosion Prediction Procedure (RUSLE2)
Manual
Describes the method established by headquarters Office of Hydraulics and Stormwater Design for the prediction of erosion rates before, during, and after construction of Caltrans projects to meet the erosion and sediment control and TMDL requirements identified in the Caltrans Permit, the CGP, and/or the LTCGP.
1. There may be other relevant manuals that pertain to specific enforcement or general criteria; see Table 1-2 for additional manuals and links.
Construction Site Best Management Practices (BMP) Manual Section 1 1-6
Table 1-2 presents website links for Caltrans manuals, procedures, and other documents. This Manual is intended as guidance for Construction Operations within Caltrans ROW. Any users should follow the NPDES Permit, the Caltrans SWMP, the Caltrans Standard Specifications, and then lastly any stormwater guidance documents.
Table 1-2. Stormwater-Related Websites
Description Websites
EPA U.S. Environmental Protection Agency http://www.epa.gov Laws/ Regulations Code of Federal Regulations (CFR) http://www.gpo.gov/fdsys/browse/collectionCfr.action?co llectionCode=CFR
NPDES Permit Caltrans NPDES Statewide Stormwater Permit (Caltrans Permit)
https://www.waterboards.ca.gov/water_issues/programs/
stormwater/caltrans.html
NPDES Permit Construction General Permit (CGP) https://www.waterboards.ca.gov/water_issues/programs/ stormwater/construction.html
NPDES Permit Lake Tahoe Construction General Permit (LTCGP) https://www.waterboards.ca.gov/water_issues/programs/ stormwater/construction.html
NPDES Permit Industrial General Permit (IGP) https://www.waterboards.ca.gov/water_issues/programs/ stormwater/industrial.html
Caltrans Stormwater
Program
Caltrans Statewide Stormwater Program –
Headquarters Division of Environmental Analysis
https://dot.ca.gov/programs/environmentalanalysis/stormwater-management-program State Water Resources
Control Board SWRCB SMARTS https://smarts.waterboards.ca.gov/smarts/faces/SwSmartsLogin.xhtml Caltrans Stormwater
Manual
Division of Construction - Stormwater Quality Link.
Contains links to resources for developing SWPPP,
WPCP, field guide to construction site dewatering
and other manuals and resources.
https://dot.ca.gov/programs/construction/storm-waterand-water-pollution-control Caltrans Stormwater
Manual
Caltrans Construction Stormwater Quality manuals
and handbooks
https://dot.ca.gov/programs/construction/storm-waterand-water-pollution-control/manuals-and-handbooks Caltrans SSPs
Caltrans Construction Contract Standards
Specifications, Plans, Standard Special Provisions
(SSPs) 1
https://dot.ca.gov/programs/design/ccs-standard-plansand-standard-specifications Caltrans Stormwater
Costs Estimating
Guidance
Caltrans cost-estimating guidance https://dot.ca.gov/programs/design/cost-estimatingimprovements
1. Contract Documents could include specific project requirements such as monitoring requirements under Clean Water Act 401 WQC or 404 Permit, or others included as part of the Informational Handout. 2-1
Section 2
Caltrans Construction Stormwater
Management Program
Requirements
2.1 Stormwater Pollution Prevention Plan and Water Pollution Control Program
Caltrans requires Contractors to prepare and implement a program to effectively control water pollution during the construction of all projects (see Standard Specification Section 13 Water Pollution Control). Projects resulting in 1 acre or more of disturbed soil area (DSA) are subject to the CGP or the LTCGP depending on the project location. Caltrans Standard Specifications require that for these projects, Contractors prepare and submit a SWPPP.
If two or more small construction projects (less than 1 acre of soil disturbance) in the same corridor (typically set up by Caltrans under the same Expenditure Authorization (EA) or parent EA) are part of a larger common plan of development (1 acre or more), these small projects are also subject to the CGP or LTCGP requirement to develop and implement a SWPPP. For construction projects within a larger common plan of development, located at least one-quarter mile apart and the area between the projects is not being disturbed, each individual project may be regulated as a separate construction project. This determination is done by the Project Engineer and is further discussed in the PPDG. This does not apply for Middle-Mile Broadband Network (MMBN) Projects; see specific MMBN guidance.
There also may be instances where a SWPPP is required even when there is less than 1 acre of DSA if it is determined that the construction project poses a significant water quality risk; this determination will be made by the District/Regional NPDES Coordinator if mandated by the Regional Water Quality Control Board (RWQCB), SWRCB, or another regulatory agency. Potential examples of when this might occur could be work over a 303d waterbody and water implosions. The Contract Documents will specify whether the construction project is to be implemented as a SWPPP or a WCPP.
If a construction project exceeds 1 acre of DSA and is not hydrologically connected to Waters of the United States, it can be exempted from CGP coverage as it meets the Notice of Non-applicability (NONA) requirements. The project must be certified in SMARTS and a Technical Report must be submitted, see PPDG Section 1.4.4.
Caltrans requires that a WPCP addressing control measures be prepared and implemented by the construction Contractor for construction projects resulting in soil disturbance of less than 1 acre. The specific requirements and detailed instructions are included in Section 4 of the SWPPP/WPCP Preparation Manual. These general requirements are included in the Construction BMP Applicability Flowchart, Figure 2-1.
Construction Site Best Management Practices (BMP) Manual Section 2 2-2
Construction projects that have a DSA between 1 and less than 5 acres and have a duration of less than 1 year may qualify for a rainfall erosivity waiver under the CGP if the rainfall erosivity factor (R factor) is less than a value of five. The R factor considers project location, length of construction, and time of year, so projects that begin and complete construction within a short period are likely to qualify for a rainfall erosivity waiver. To calculate the R value, refer to Section 1.4.2.1 of no SWPPP/WPCP Preparation Manual; a link to the manual is provided in Table 1-2.
Construction projects that qualify for a rainfall erosivity waiver do not need to prepare a SWPPP but are required to submit proper documentation via SMARTS (to be exempted from the CGP) as well as prepare and implement a site-specific WPCP.
2.2 Construction BMP Applicability
The flowchart presented in Figure 2-1 guides the user as to whether the project triggers a SWPPP or a WPCP and where to find additional information, if needed. The determination for a SWPPP or a WPCP applicability will be made by the Project Engineer, but it is included here for completeness. The flowchart also includes general questions to determine applicability of BMP categories that are described in Sections 3 through 8 of this Manual.
The steps described below correspond to the steps shown in Figure 2-1.
Step 1 - Start
The Contractor, the Water Pollution Control (WPC) Manager, the Qualified SWPPP Developer (QSD) or the Qualified SWPPP Practitioner (QSP) must use Figure 2-1, the guidance provided in this section, and the SWPPP/WPCP Preparation Manual to determine the project’s entire BMP selection and applicability for the duration of the construction phase.
Step 2 - Is a Construction project being proposed?
A construction project is defined as any activity, including but not limited to, clearing, grading, grubbing, or excavation. Routine maintenance to maintain original line and grade, hydraulic capacity, or original purpose of the facility is not deemed a construction activity that requires a SWPPP or a WPCP.
If the project qualifies as a construction project, proceed to step 3.
If the project does not meet the definition of construction, then the project is subject to Maintenance BMPs; refer to the Caltrans July 2016 SWMP or the Caltrans Maintenance Staff Guide.
Step 3 - Will the project create 1 acre or more of DSA? If the construction project will disturb more than 1 acre of soil it is subject to either the CGP or the LTCGP depending on its location and an up-to-date SWPPP must be prepared and maintained during the entire project duration.
If the construction project disturbs less than 1 acre of soil, the project must have a WPCP prepared and implemented; see Section 4 of the SWPPP/WPCP Preparation Manual for specific instructions.
Step 4- Can the construction project qualify for a Notice of Non-applicability (NONA)? If the construction project exceeds 1 acre of DSA and is not hydrologically connected to waters of the United States, the project can qualify for a NONA.
If you answered yes, the project does not need coverage under the CGP but it still requires certification in SMARTS and a No Discharge Technical Report must be uploaded. In addition, a WPCP must be prepared and implemented.
If the project does not qualify for a NONA, proceed to step 5.
Construction Site Best Management Practices (BMP) Manual Section 2 2-3
Step 5 - Can the construction project qualify for a Rainfall Erosivity Waiver? If a project will be of short duration and is more than 1 acre but less than 5 acres of soil disturbance, it might qualify for an EPA rainfall erosivity waiver as discussed in Section 1.4.2 of the SWPPP/WPCP Preparation Manual.
If you answered yes, the project does not need coverage under the CGP but it still requires some paperwork to be filed via SMARTS. In addition, a WPCP must be prepared and implemented.
If you answered no, then project is subject to SWPPP requirements. See Section 3 of the SWPPP/WPCP Preparation Manual for further guidance on SWPPP preparation.
Step 6- Are any soil areas expected to be exposed and need stabilization as part of the project or is there a need to stabilize concentrated flow conveyances? Projects are required to implement appropriate controls year-round. If the project has exposed soil areas or unlined conveyances, the WPC Manager or QSP must be diligent in ensuring appropriate BMPs are implemented. See Section 3 of this Manual for specific BMP factsheets and proceed to Step 6. For further guidance on proper selection and costs, see Appendix B of this Manual.
If there are no soil areas needing stabilization and no unstable conveyances, then proceed to Step 6.
Step 7 - Will the project require temporary controls to intercept/slowdown on-site or off-site flows? If the project has areas where offsite flows are coming onto the project area, flows should be prevented from commingling with materials, operations or contaminants, including soil, to prevent them from being carried by the offsite flows. Onsite flows must be conveyed in accordance with HDM Section 800 to reduce potential for turbid flows. See Section 4 of this Manual for specific BMP factsheets to control sediment-laden runoff.
Step 8 - Will the project require a dust control plan or is there a potential for dust control BMPs to be applicable?
Use Section 5 of this Manual for specific BMP factsheets if the contract documents require the preparation and implementation of a Dust Control Plan or if there is a potential for dust to be generated at any time during the duration of the construction project.
Step 9 - Will the project require tracking controls in any area within project limits? Any areas where construction vehicles are entering or exiting the project must be stabilized to prevent tracking of sediment or other materials. See Section 6 of this Manual for specific BMP factsheets for tracking control. Additionally, SC-7, Street Sweeping should be evaluated and implemented either on its own or in combination with other BMPs to ensure compliance with all permits and contract documents.
Step 10 - Will the project day-to-day operations require good housekeeping practices or have a need for non-stormwater BMPs?
Section 7 of this Manual includes a list of source control BMPs that prevent pollution by limiting or reducing potential pollutants at their source before they come in contact with stormwater.
Step 11 - Will the project include material storage, spill prevention needs, waste management, or other housekeeping practices?
All materials or wastes either stored or generated during the construction phase must be properly stored and disposed. Section 8 of this Manual includes lists of BMPs that must be used at the Contractor’s yard, where the materials are stored, or where construction activities are being conducted to ensure proper usage, containment, and disposal of materials and waste products.
Construction Site Best Management Practices (BMP) Manual Section 2 2-4
END - Specific BMP factsheets must be reviewed, and the Project’s SWPPP or WPCP text and tables, along with the Water Pollution Control Drawings and the Water Pollution Control Schedule must be modified to ensure appropriate controls are implemented year-round.
Figure 2-1. Construction Site BMP Applicability Flowchart Construction Site Best Management Practices (BMP) Manual Section 2 2-5
2.3 Minimum Construction BMPs
This section provides the minimum construction BMPs required for a project subject to the CGP or the LTCGP or one that requires WPCP preparation and implementation. It is important to note that the requirements of this Section are minimum requirements, and that Caltrans contracts may impose more-stringent requirements. Working details of Construction Site BMPs are presented in Sections 3 through 8 of this Manual.
Construction Site BMPs (also sometimes called temporary control practices or BMPs) are best conventional technology/best available technology (BCT/BAT)-based BMPs that are consistent with the BMPs and control practices required under the CGP and the LTCGP. Caltrans Construction Site BMPs are divided into six categories, as shown in Table 2-1.
Stormwater pollution control requirements are intended to be implemented on a year-round basis at an appropriate level. The requirements must be implemented in a proactive manner during all seasons while construction is ongoing. Appropriate water pollution control includes the implementation of an effective combination of both soil stabilization and sediment controls, implementation of wind erosion measures, tracking controls, non-stormwater and waste management, and material pollution BMPs. Some BMPs can be implemented as a standalone device while others can be combined to improve effectiveness and compliance.
Section 2 of the SWPPP/WPCP Preparation Manual describes in detail specific requirements under the applicable CGP. The CGP and LTCGP both require minimum controls and require BMPs based on the projects’ calculated risk level to apply linear sediment controls along the toe of the slope, face of the slope, and at the grade breaks of exposed slopes to comply with sheet flow lengths.
Table 2-1. Construction Site BMPs
ID BMP Name
Minimum
Requirement4
CGP
Minimum
Requirement4
LTCGP
Temporary Soil Stabilization
SS-1 Scheduling X X
SS-2 Preservation of Existing Vegetation X X
SS-3 Temporary Hydraulic Mulch X1 X1
SS-4 Temporary Hydroseed X1 X1
SS-5 Temporary Soil Binder X1 X1
SS-6 Temporary Tacked Straw X1 X1
SS-7 Temporary Cover and Rolled Erosion Control Products (RECP) X1 X1 SS-8 Temporary Mulch X1 X1
SS-9 Earth Dikes/Drainage Swales & Lined Ditches - -
SS-10 Outlet Protection/Velocity Dissipation Devices2 X X SS-11 Slope Drains - -
SS-12 Streambank Stabilization - -
Construction Site Best Management Practices (BMP) Manual Section 2 2-6
Table 2-1. Construction Site BMPs
ID BMP Name
Minimum
Requirement4
CGP
Minimum
Requirement4
LTCGP
Temporary Sediment Control
SC-1 Temporary Silt Fence X1 X1
SC-2 Sediment/Desilting Basin - -
SC-3 Sediment Trap/Curb Cutback - -
SC-4 Temporary Check Dam - -
SC-5 Temporary Fiber Rolls X1 X1
SC-6 Temporary Gravel Bag/Earthen Berm X1 X1
SC-7 Street Sweeping X -
SC-8 Sandbag Barrier - X
SC-9 Temporary Straw Bale Barrier X1 X1
SC-10 Temporary Drainage Inlet Protection X X
SC-11 Temporary Compost Sock X1 X1
SC-12 Flexible Sediment (Temporary Foam) Barrier X1 X1
Wind Erosion Control
WE-1 Wind Erosion Control X X
Tracking Control
TC-1 Temporary Construction Entrance X X
TC-2 Temporary Construction Roadway - -
TC-3 Temporary Entrance/Outlet Tire Wash - -
Non-Stormwater Management
NS-1 Water Conservation Practices - -
NS-2 Dewatering - X3
NS-3 Paving, Sealing, Saw Cutting, Grooving, and Grinding Activities X X NS-4 Temporary Stream Crossing - -
NS-5 Clear Water Diversion - -
NS-6 Illegal Connection and Illicit Discharge Detection and Reporting X X NS-7 Potable Water/Irrigation - -
NS-8 Vehicle and Equipment Cleaning X X
NS-9 Vehicle and Equipment Fueling X X
NS-10 Vehicle and Equipment Maintenance X X
NS-11 Pile Driving - -
NS-12 Concrete Curing - -
NS-13 Material and Equipment Use Over Water - -
NS-14 Concrete Finishing - -
NS-15 Structure Removal Over or Adjacent to Water - -
Construction Site Best Management Practices (BMP) Manual Section 2 2-7
Table 2-1. Construction Site BMPs
ID BMP Name
Minimum
Requirement4
CGP
Minimum
Requirement4
LTCGP
Waste Management and
Materials Pollution Control
WM-1 Material Delivery and Storage X X
WM-2 Material Management X X
WM-3 Stockpile Management X X
WM-4 Spill Prevention and Control X X
WM-5 Solid Waste Management X X
WM-6 Hazardous Waste Management - X
WM-7 Contaminated Soil Management - X
WM-8 Concrete Waste Management X X
WM-9 Sanitary and Septic Waste Management X X
WM-10 Liquid Waste Management - X
1. Can be selected as a standalone BMP or a combination of temporary soil stabilization BMPs depending on site conditions; minimum requirement is met when the individual BMP or the combination is properly implemented.
2. Only applicable when outlet protection/velocity dissipation is required.
3. When dewatering is expected, must have a dewatering and/or diversion plan as required under LTCGP Section N, or CGP Attachment J if no specific dewatering permit is applicable.
4. Minimum requirements are based on CGP Attachment D and LTCGP.
2.3.1 Surface Water Buffers
A surface water buffer is a 50-foot undisturbed natural buffer from the edge of DSAs to any receiving water’s top of bank. Where surface water buffers cannot be maintained, The CGP requires the project to provide and maintain an undisturbed natural buffer that is less than 50 feet and is supplemented by erosion and sediment controls that achieve, in combination, the sediment load reduction equivalent to a 50-foot undisturbed natural buffer. The equivalent sediment load may be calculated using the Revised Universal Soil Loss Equation, version 2 (RUSLE2) or another method approved by the Regional Water Board.
2.4 BMP Inspection Frequency
The SWPPP or WPCP implemented on Caltrans construction projects includes specific visual monitoring requirements to comply with the CGP, LTCGP, and/or Caltrans Permit. All BMPs deployed on construction sites must be inspected on a frequency as described below. Improperly installed or damaged BMPs must be corrected immediately, unless a later date is approved by the Resident Engineer (RE). Corrections must be made before the onset of forecasted rain event, qualifying precipitation event (QPE), or qualifying rain event as used by the Caltrans standard specifications, the CGP, and/or the LTCGP. Routine inspections of Construction Site BMPs are to be conducted at a minimum as follows:
• Daily for LTCGP projects
• Daily for certain activities for SWPPPs or WPCPs
• Within 72 hours prior to a QPE
Construction Site Best Management Practices (BMP) Manual Section 2 2-8
• Within 2 days after a QPE if 0.5 inches or more precipitation is measured during the duration of the QPE using the on-site rain gauge
• At 24-hour intervals during extended rain events
• Weekly throughout the duration of the construction project Some visual inspections are required to be performed by specific personnel under the CGP, while all other routine inspections may be performed by a trained delegate.
The following inspections must be performed by a QSD:
• Once within 30 days of construction activities starting • Once within 30 days of a change in site QSD
• Once between August 1 and October 31 of each year
• Once between January 1 and March 31 of each year
• Within 14 calendar days after a numeric action level exceedance • Within 14 calendar days of an inactive project status • As requested by Water Board staff
The following inspections must be performed by a QSP:
• Once every calendar month
• Once within 72 hours of each forecasted QPE
• Within 14 days after a numeric action level exceedance • Before the final Notice Of Termination (NOT) or Change Of Information (COI) of all or part of the site
Table 2-2 shows the monitoring requirements for projects subject to CGP. The SWPPP/WPCP Preparation Manual includes more details on what each inspection should include.
Table 2-2. Monitoring Requirements for CGP
Risk Level
Visual
Inspections
Pre-storm
Weekly/Daily 1
(if applicable)
Visual
Inspections
Post-storm
Daily Storm
BMP 2
Visual
Inspections
Post-Storm
Sampling 3
Non-visible
Pollutant
Sampling 3
Stormwater
Discharge
Sampling 3
Receiving
Water
CGP 1 X X X X - -
CGP 2 X X X X X -
CGP 3 X X X X X X
1. A pre-, during, or post-QPE inspection also satisfies the daily visual inspection requirement.
2. Visual inspections are not required during dangerous weather conditions or when access to the site is infeasible (e.g., due to snow accumulation) or unsafe.
3. Other sampling, such as ATS, might be required but it is based on site operations and not risk level.
Construction Site Best Management Practices (BMP) Manual Section 2 2-9
Under the LTCGP, inspections of Construction Site BMPs are to be conducted at a minimum as follows:
• Prior to a forecasted storm event
• After a qualified rain event that causes runoff from the construction site • At 24-hour intervals during extended rain events
• Daily throughout the duration of the construction project Table 2-3 shows the monitoring requirements for projects subject to the LTCGP. The SWPPP/WPCP Preparation Manual and Construction Site Monitoring Guidance Manual includes more details on what each inspection should include.
Table 2-3. Monitoring Requirements for LTCGP
Visual
Inspections
Daily, including
Non-stormwater
Discharges
Visual
Inspections
Pre-storm
Baseline
Visual
Inspections
Pre-storm
REAP
Visual
Inspections
Post-storm
Post-storm
Sampling
Non-visible
Pollutant
Sampling
Stormwater
Discharge
Sampling
Receiving
Water
LTCGP X X X X X X X
3-1
Section 3
Temporary Soil Stabilization BMP
3.1 Temporary Soil Stabilization
Temporary soil stabilization consists of preparing the soil surface and applying one of the BMPs shown in Table 3-1, or a combination thereof, to DSAs. Temporary soil stabilization must be applied to DSAs of construction projects in conformance with Contract Documents and this Manual. Refer to Appendix B for additional guidance on the selection of temporary soil stabilization controls.
SS-1
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Scheduling SS-1
March 2024 1 of 3
Scheduling
Standard Symbol
Definition and Purpose
This BMP involves developing, for every project, a schedule that includes construction activity sequencing with implementation of construction site BMPs such as temporary soil stabilization and temporary sediment control measures. The purpose is to reduce the amount and duration of soil exposed to erosion by wind, rain, runoff, and vehicle tracking, and to perform the construction activities and control practices in accordance with the planned schedule.
Appropriate Applications
Construction sequencing should be scheduled to minimize land disturbance during the wetter months for all projects. In addition, any construction windows required by regulatory permits, and any winter suspension work, should be described in the schedule. Appropriate BMPs must be implemented year-round.
Limitations
Environmental constraints such as nesting season prohibitions reduce the full capabilities of this BMP.
Standards and Specifications
General Requirements
■ Developing a schedule and planning the project operations to minimize erosion and the potential to discharge pollutants to stormwater are the critical first steps in an effective stormwater program. The construction schedule must be incorporated into the Stormwater Pollution Prevention Plan (SWPPP) or Water Pollution Control Program (WPCP). Refer to Scheduling SS-1
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Scheduling SS-1
March 2024 2 of 3
Section 8 and 13 of the Standard Specifications for specific requirements of what the schedule must include for water pollution control.
■ The schedule should clearly show when work activities that could pollute stormwater with sediment or other contaminants (e.g., grading, move-in, move-out, stockpiling, pile driving) would occur and when soil stabilization, sediment control, and other BMPs associated with each phase of construction would be implemented.
■ The schedule should include details on the implementation and deployment of BMPs related to:
− Temporary and permanent soil stabilization
− Temporary sediment control
− Tracking control
− Wind erosion control
− Non-stormwater
− Waste management and materials pollution control
■ The schedule needs to be updated as part of the SWPPP annual winterization plan. ■ The schedule should also include dates for significant long-term operations or activities that may have planned non-stormwater discharges, such as dewatering, saw cutting, grinding, drilling, boring, crushing, blasting, painting, hydro-demolition, mortar mixing, bridge cleaning, etc. ■ The construction schedule should reflect requirements for in-water work and other construction activities with potential to disturb water and biological resources specified in regulatory agency permits and approvals (RWQCB 401 Water Quality Certification, U.S. Army Corps of Engineers 404 permit, 1602 permit, etc.).
■ The construction schedule should also include dates when an active or passive treatment system is expected to be used. There are specific notification requirements in SMARTS that need to be processed prior to the commencement of these systems.
Recommendations
■ Schedule work to minimize soil-disturbing activities during predicted rain events. Consider rescheduling activities for dry periods to minimize maintenance requirements. ■ Develop the sequencing and timetable for the start and completion of each item, such as site clearing and grubbing, grading, excavation, paving, pouring foundations, installing utilities, etc., to minimize the active construction area.
■ Schedule major grading operations during dryer months when practical. ■ Stabilize inactive areas within 15 days from the cessation of soil-disturbing activities or 1 day prior to the onset of precipitation, whichever occurs first. It is important to consider manufacturer’s recommendations for the selected soil stabilization BMP to ensure they meet the minimum dry time required. See Appendix B of this Manual for additional guidance. ■ Monitor the weather forecast for storm events, which are storms that produce or are forecast to produce at least 0.1 inch of precipitation within a 24-hour period. There is a qualifying precipitation event per CGP that begins with the 24-hour period when 0.5 inches has been forecast and continues on subsequent 24-hour periods when 0.25 inches of precipitation or more is forecast. When a rain event is predicted, adjust the construction schedule to allow the Scheduling SS-1
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Scheduling SS-1
March 2024 3 of 3
implementation of soil stabilization, sediment controls, and, if applicable, sediment treatment controls on all disturbed areas prior to the onset of rain. ■ Ensure an ample supply of BMP materials are on site in order to quickly mobilize and implement required BMPs, particularly ahead of rain events when materials may be in short supply or back ordered.
■ Be prepared year-round to deploy soil stabilization and sediment control practices. Erosion may be caused during dry seasons by unseasonal rainfall, wind, and vehicle tracking. Keep the site stabilized year-round, and retain and maintain sediment trapping devices in operational condition.
■ Sequence trenching activities so that most open portions are closed before new trenching begins. Trenched material should be stored on the upstream side of the trenches. ■ Incorporate staged seeding and re-vegetation of graded slopes as work progresses. ■ Consider the early planting and establishment of permanent vegetation in the schedule to maximize plant establishment success and minimize irrigation and continuous maintenance needs.
■ Apply permanent erosion control to areas deemed substantially complete during the project’s defined seeding window
Maintenance and Inspection
■ Verify that work is progressing in accordance with the schedule. If progress deviates, take corrective actions.
■ Keep the schedule up to date and ensure it is consistent with the Contractor’s 3-week lookahead or other routine schedule submitted to the RE under the contract. ■ Amend the schedule when changes are warranted or when directed by the RE.
SWPPP or WPCP
■ A Water Pollution Control Schedule (WPCS) must include construction operations and BMP implementation for the entire duration of the project. The WPCS is to be included as an attachment (Attachment I) and discussed in Sections 600.1.1 and 600.1.2 of the SWPPP and Section 30.2.1 of the WPCP.
SS-2
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Preservation of Existing Vegetation SS-2 March 2024 1 of 4
Preservation of Existing Vegetation
Standard Symbol
Definition and Purpose
Preservation of existing vegetation is the identification and protection of desirable vegetation that provides erosion and sediment control benefits.
Appropriate Applications
■ To preserve existing vegetation at areas on a site where no construction activity is planned or will occur at a later date. This BMP is very applicable for multi-year or multiple location projects, for which existing vegetation can be preserved until the area becomes active. ■ On a year-round basis, temporary fencing shall be provided prior to the start of clearing and grubbing operations or other soil-disturbing activities in areas. ■ Clearing and grubbing operations should be staged to preserve existing vegetation. ■ Areas where natural vegetation exists and is designated for preservation. Such areas often include steep slopes, a watercourse, and building sites in wooded areas. ■ Areas where local, state, and federal government require preservation, such as vernal pools, wetlands, marshes, certain oak trees, etc. Clearly marking and leaving a buffer area around these unique areas during construction will help to preserve these areas as well as take advantage of natural erosion prevention and sediment trapping. ■ For any trenching or tunneling. Trenching shall be as far away from tree trunks as possible, usually outside of the tree drip line or canopy. Curve trenches around trees to avoid large roots or root concentrations. If roots are encountered, consider tunneling under them.
Preservation of Existing Vegetation SS-2
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Preservation of Existing Vegetation SS-2 March 2024 2 of 4
■ When trenching and/or tunneling near or under trees are to be retained, tunnels shall be at least 8 inches below the ground surface, and not below the tree center, to minimize impact on the roots. Tree roots shall not be left exposed to air; they shall be covered with soil as soon as possible, protected, and kept moistened with wet burlap or peat moss until the tunnel and/or trench can be completed.
Limitations
■ Protection of existing vegetation requires planning and may limit the area available for construction activities.
■ For sites with diverse topography, it is often difficult and expensive to save existing trees while grading the site satisfactorily for the construction project.
Standards and Specifications
General Requirements
■ Specifications for preservation of existing vegetation can be found in Standard Specifications Section 5-1.36A.
■ Section 14 “Environmental Stewardship” of the Standard Specifications specifies the requirements related to environmental compliance and resource management, including requirements related to Environmentally Sensitive Areas (ESA). ■ Refer to Section 16-2.03 of the Standard Specifications for “Temporary High-Visibility Fences” used to delineate ESAs.
■ Refer to 16-2.04 of the Standard Specifications for “Temporary Construction Mats” used to protect wetlands and other areas.
Schedule
■ Preservation of existing vegetation must be provided prior to the start of clearing and grubbing operations or other soil-disturbing activities in areas identified on the plans to be preserved, including areas designated as ESAs.
■ Preservation of existing vegetation should conform to scheduling requirements set forth in the special provisions.
Design and Layout
■ Mark areas to be preserved with temporary fencing (Temporary High-Visibility Fence). The temporary fencing must be made of high-visibility fabric secured with 6-foot (minimum) posts.
Refer to Section 16-2.03B of the Standard Specifications for more information on temporary high-visibility fence materials.
■ Fence posts can be either wood or steel, at the Contractor’s discretion, as appropriate for the intended purpose. The post spacing must be 8 feet center-to-center (maximum) and embedded at least 16 inches into the ground to completely support the fence in an upright position. ■ See Standard Plan T65 for “Temporary Water Pollution Control Details (temporary high-visibility fence).”
Preservation of Existing Vegetation SS-2
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Preservation of Existing Vegetation SS-2 March 2024 3 of 4
Installation
■ Construction materials, equipment storage, and parking areas should be located where they will not cause damage to vegetation designated for preservation. This could include keeping equipment away from trees to prevent trunk and root damage, considering the impact of grade changes to existing vegetation and the root zone, and minimizing disturbed areas by avoiding stands of trees and shrubs and following existing contours to reduce cutting and filling for temporary roads.
■ Maintain existing irrigation systems.
■ Employees and subcontractors must be instructed to honor protective devices. No heavy equipment, vehicular traffic, or storage piles of any construction materials is permitted within the drip line of any tree to be retained. Removed trees should not be felled, pushed, or pulled into any retained trees. Fires should not be permitted within 100 feet of the drip line of any retained trees. Any fires must be of limited size and must be kept under continual surveillance. No toxic or construction materials (including paint, acid, nails, gypsum board, chemicals, fuels, and lubricants) should be stored within 50 feet of the drip line of any retained trees, nor disposed of in any way that would injure vegetation.
■ The last activity after all other work is complete is to remove fences and barriers. This is to help protected trees that may otherwise be destroyed by carelessness during the final cleanup and landscaping.
Preservation of Existing Vegetation SS-2
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Preservation of Existing Vegetation SS-2 March 2024 4 of 4
SS-3
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Hydraulic Mulch SS-3 March 2024 1 of 3
Temporary Hydraulic Mulch
Standard Symbol
Definition and Purpose
Temporary hydraulic mulch consists of using hydroseeding equipment to apply a mixture of natural fibers and a stabilizing compound to temporarily protect exposed soil from erosion caused by raindrop impact or wind. This is one of five temporary soil stabilization alternatives to consider.
Appropriate Applications
■ Temporary hydraulic mulch is applied to disturbed areas that require temporary protection until permanent vegetation is established, or disturbed areas that must be re-disturbed following an extended period of inactivity.
Limitations
■ Wood fiber hydraulic mulches are generally short-lived (only last a part of a growing season) and require time (24 hours or more) to dry before rainfall occurs to be effective. ■ Paper mulches are not permitted.
■ Avoid use in areas where the mulch would be incompatible with immediate future earthwork activities and would have to be removed.
■ Cellulose fiber mulches alone may not perform well on steep slopes or in coarse soils.
Temporary Hydraulic Mulch SS-3
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Hydraulic Mulch SS-3 March 2024 2 of 3
Standards and Specifications
General Requirements
■ See Standard Specifications Section 13-5.03D to 13-5.03G for placing various types of hydraulic mulch.
■ Standard Specifications Section 21-2.02D and 21-2.02E contain material specifications for fiber and tackifier, respectively.
■ A certificate of compliance, as required under Standard Specifications Section 21-2.01C(4), is required for tackifier and bonded fiber matrix (BFM).
■ Hydraulic matrices require time to dry before rainfall occurs to be effective. Refer to the manufacturer’s specifications for drying times.
■ Avoid mulch over-spray onto the traveled way, sidewalks, lined drainage channels, and existing vegetation.
■ Selection of hydraulic mulches by the Contractor must be approved by a licensed professional. ■ Prior to application, roughen embankment and fill areas by rolling with a crimping or punchingtype roller or by track walking. Track walking should only be used where other methods are impractical.
Temporary Hydraulic Mulch
■ Temporary hydraulic mulch contains mixtures of fiber and tackifier that is applied to soil with hydraulic spray equipment.
■ Fiber for temporary hydraulic mulch must be at least 50 percent wood fiber. The remaining percentage must be cellulose fiber, alternate fiber, or a combination of these fibers. ■ Temporary hydraulic mulch application rates must follow the manufacturer’s recommendations.
If not provided, apply at a rate of 2,000 pounds per acre (lb/ac). ■ Tackifier should be applied per the manufacturer's instructions for the slope, soil, and wind conditions
Temporary BFM Hydraulic Mulch
■ BFM contains 100 percent wood fiber and tackifier, sometimes combined with seed and fertilizer that is applied to soil hydraulically.
■ BFM application rates must follow the manufacturer’s recommendations. If not provided, apply at a rate of 3,500 lb/ac.
■ Tackifier used for BFM must be:
− Bonded to the fiber or prepackaged with the fiber by the manufacturer − Contain a minimum of 10 percent of the combined weight of the dry fiber, activating agents, and additives
− Organic, high-viscosity colloidal polysaccharide with activating agents or a blended hydrocolloid-based binder
Temporary Hydraulic Mulch SS-3
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Hydraulic Mulch SS-3 March 2024 3 of 3
Temporary Cementitious Binder Hydraulic Mulch
■ Temporary cementitious binder hydraulic mulch is a mixture of fiber and a cementitious binder that is applied to soil with hydraulic spray equipment. ■ Application rates of temporary cementitious binder hydraulic mulch must be according to the manufacturer’s specifications. If not provided, apply at a rate of 2,000 lb/ac; apply cementitious binder at a rate of 4,000 lb/ac.
■ Additional standards for cementitious binder are provided in Standard Specifications Section 13
5.03G.
■ Additional guidance on the selection of soil stabilization BMPs can be found in Appendix B of this Manual.
Maintenance and Inspections
■ A certificate of compliance under Standard Specifications Section 21-2.01C(4) for the applicable BMP must be submitted to the Resident Engineer prior to application to ensure proper mix is being used.
■ It is recommended that a small test area/mock-up occur prior to large-area application to verify sufficient cover for the approved mix.
■ Maintain unbroken, temporary mulched ground cover throughout construction when the soils are not being reworked. Inspect before expected rainstorms, and repair any damaged ground cover and re mulch exposed areas of bare soil.
■ After any rainfall event, the Contractor is responsible for maintaining all slopes to prevent erosion.
■ Areas where temporary hydraulic mulch Temporary will be implemented must be shown in the WPCDs and match site conditions.
SWPPP or WPCP
■ Temporary hydraulic mulch, temporary BFM hydraulic mulch or temporary cementitious hydraulic mulch must be discussed in Section 600.1.2 of the SWPPP, or Section 30.2.1 of the WPCP.
SS-4
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Hydroseed SS-4
March 2024 1 of 3
Temporary Hydroseed
Standard Symbol
Definition and Purpose
Temporary hydroseed typically consists of applying a mixture of wood, fiber, seed, fertilizer, and stabilizing emulsion with hydromulch equipment, which temporarily protects exposed soils from erosion by water and wind.
Appropriate Applications
■ Hydroseeding is applied on disturbed soil areas that require temporary protection until permanent vegetation is established, or on disturbed soil areas that must be re-disturbed following an extended period of inactivity.
■ Can be used in conjunction with other rolled erosion control products.
Limitations
■ Hydroseeding may be used alone only when there is sufficient time in the season to ensure adequate vegetation establishment and erosion control. Otherwise, hydroseeding must be used in conjunction with a soil binder or mulch, such as temporary soil binders (see SS-5) and temporary tacked straw (see SS-6).” Temporary Tacked Straw ■ Steep slopes are difficult to protect with temporary seeding. ■ Temporary seeding may not be appropriate in dry periods without supplemental irrigation. ■ Temporary vegetation may have to be removed before permanent vegetation is applied. ■ Temporary vegetation is not appropriate for short-term inactivity. ■ Hydroseeding should not be used in areas subject to heavy traffic. ■ Hydroseeding could trigger non-visible sampling if the appropriate application timeframe (before a rain event) and manufacturer recommendations are not followed.
Temporary Hydroseed SS-4
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Hydroseed SS-4
March 2024 2 of 3
Standards and Specifications
General Requirements
■ Refer to Standard Specifications Section 13-5.03I “Temporary Hydroseed.” ■ To select appropriate hydroseeding mixtures, an evaluation of site conditions shall be performed with respect to:
− Soil conditions − Maintenance requirements
− Site topography − Sensitive adjacent areas
− Season and climate − Water availability
− Vegetation types − Plans for permanent vegetation
■ Selected hydroseeding mixtures must be approved by the licensed professional. ■ Seed mix must comply with Standard Specifications Section 21-2.02F “Seed” and the project’s special provisions.
■ Seed may be dry applied to small areas not accessible by hydroseeding equipment if authorized.
■ Seeds must not contain seeds of prohibited noxious weeds and must not contain more than 1.0 percent total weed seed by weight. Seeds must be delivered to the project site with each species in separate, unopened containers with the seed tag attached. Measure individual seed species and mix in the presence of the RE.
■ Fiber must be at least 50 percent wood fiber. The remaining percentage must be cellulose fiber, alternate fiber, or a combination of these fibers.
■ Commercial fertilizer must conform to the requirements of the California Food and Agricultural Code. Fertilizer can be pelleted or granular form.
Application Procedures
■ Prior to application, roughen the slope, fill area, or area to be seeded with the furrows trending along the contours. Rolling with a crimping or punching-type roller, or track walking, is required on all slopes prior to hydroseeding. Track walking should only be used where other methods are impractical.
■ Add water to hydroseed materials as recommended by the manufacturer and mix sufficiently to ensure an even application. A dispersing agent may be added to the mixture if authorized. ■ Equipment must have a built-in continuous agitation and discharge system capable of producing a homogeneous mixture and a uniform application rate. The tank must have a minimum capacity of 1,000 gallons. A smaller tank can be used if authorized by the RE. ■ Apply temporary hydroseed at the following rates:
− Apply seed at rates specified in the project’s erosion control plans. − Apply fiber at 2,000 pounds per acre.
− Apply tackifier according to manufacturer’s recommendations for the slope, soil, and wind conditions.
Temporary Hydroseed SS-4
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Hydroseed SS-4
March 2024 3 of 3
− Apply materials in locations, rates, and number of applications shown and as follows:
− Start application within 60 minutes after adding seed to the tank. − Apply in successive passes as necessary to achieve the specified application rate. − Apply all hydroseed materials shown for a single area within 72 hours. ■ If hydroseed materials are applied to areas covered by rolled erosion control products (RECP), apply hydroseed materials to the RECP as follows:
− Verify the RECP is in uniform contact with the slope surface. − Spray materials into the RECP perpendicular to the slope and integrate well. − Do not displace or damage the RECP.
− After the final application, do not allow pedestrians or equipment on the treated areas. − Follow-up applications shall be made as needed to cover weak spots and to maintain adequate soil protection.
− Avoid over-spray onto the traveled way, sidewalks, lined drainage channels, and existing vegetation.
■ Additional guidance on the selection of soil stabilization BMPs can be found in Appendix B of this Manual.
Maintenance and Inspection
All seeded areas must be inspected for failures and re-seeded, fertilized, and mulched within the planting season, using not less than half the original application rates. Any temporary revegetation efforts that do not provide adequate cover must be reapplied at a scheduled recommended by the licensed professional.
■ A certificate of compliance under Standard Specifications Section 21-2.01C(4) for the applicable BMP must be submitted to the RE prior to application to ensure proper mix is being used. ■ It is recommended that a small test area/mock-up occur prior to large-area application to verify sufficient cover for the approved mix.
■ After any rain event, the Contractor is responsible for maintaining all slopes to prevent erosion. ■ Areas where hydroseeding will be implemented must be shown in the WPCDs. Application timeframes (dates) must be included in the WPCS.
■ Must ensure correct application rates and passes (different directions) take place to ensure adequate coverage.
SWPPP or WPCP
■ Hydroseeding must be discussed in Section 600.1.2 of SWPPP, or in Section 30.2.1 of the WPCP
SS-5
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Soil Binder SS-5 March 2024 1 of 6
Temporary Soil Binder
Definition and Purpose
Temporary soil binder consists of applying and maintaining a soil stabilizer to exposed soil surfaces.
Soil binders are materials applied to the soil surface to temporarily prevent water-induced erosion of exposed soils on construction sites. Soil binders also provide temporary dust, wind, and soil stabilization (erosion control) benefits. This is one of five temporary soil stabilization alternatives to consider.
Appropriate Applications
Temporary soil binder is typically applied to disturbed areas requiring short-term temporary protection. Because soil binder can often be incorporated into the work, it may be a good choice for areas where grading activities will soon resume. It can be applied on stockpiles to prevent water and wind erosion.
Limitations
■ Soil binders are temporary in nature and may need reapplication. ■ Soil binders require a minimum curing time until fully effective, as prescribed by the manufacturer. Soil binders may need reapplication after a storm event. ■ Soil binders will generally experience spot failures during heavy rainfall events. If runoff penetrates the soil at the top of a slope treated with a soil binder, it is likely that the runoff will undercut the stabilized soil layer and discharge at a point further down slope. ■ Soil binders do not hold up to pedestrian or vehicular traffic across treated areas.
Temporary Soil Binder SS-5
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Soil Binder SS-5 March 2024 2 of 6
■ Soil binders may not penetrate soil surfaces made up primarily of silt and clay, particularly when compacted.
■ Some soil binders may not perform well with low relative humidity. Under rainy conditions, some agents may become slippery or leach out of the soil.
■ Soil binders may not cure if low temperatures occur within 24 hours of application.
Standards and Specifications
General Considerations
■ Site-specific soil types will dictate appropriate soil binders to be used. ■ A soil binder must be environmentally benign (non-toxic to plant and animal life), easy to apply, easy to maintain, and economical, and shall not stain paved or painted surfaces. Refer to Standard Specifications Section 13,18 and 21.
■ Some soil binders are compatible with existing vegetation. ■ Performance of soil binder performance depends on temperature, humidity, and traffic across treated areas.
■ Avoid over-spray onto the traveled way, sidewalks, lined drainage channels, and existing vegetation.
■ Storm water quality runoff sampling is required for many soil binders. Refer to the Construction Site Monitoring Program Guidance Manual to determine if the applicable copolymers/polymers require non-visible sampling. The following binders have been found as not discharging pollutants, and therefore water quality sampling and analysis is not required for them: Super Tak, M-binder, Fish Stik, Pro40dc, Fisch-Bond, Soil Master WR, and EarthGuard.
Soil Binder Applications
■ After selecting an appropriate soil binder, the untreated soil surface must be prepared before application. The untreated soil surface must contain sufficient moisture to assist the agent in achieving uniform distribution. In general, the following steps shall be followed:
− Follow manufacturer’s recommendations for application rates, pre-wetting of application area, and cleaning of equipment after use.
− Prior to application, roughen embankment and fill areas by rolling with a crimping or punching-type roller or by track walking. Track walking shall only be used where rolling is impractical.
− Consider the drying time for the selected soil binder and apply with sufficient time before anticipated rainfall. Soil binders shall not be applied during or immediately before rainfall. − Avoid over-spray onto the traveled way, sidewalks, lined drainage channels, sound walls, and existing vegetation.
− Soil binders shall not be applied to frozen soil, areas with standing water, under freezing or rainy conditions, or when the air temperature is below 4o C (40oF) during the curing period.
− More than one treatment is often necessary, although the second treatment may be diluted or have a lower application rate.
Temporary Soil Binder SS-5
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Soil Binder SS-5 March 2024 3 of 6
− Generally, soil binders require a minimum curing time of 24 hours before they are fully effective.
Refer to manufacturer’s instructions for specific cure times. ■ For liquid agents:
− Crown or slope ground to avoid ponding.
− Uniformly pre-wet ground at 0.03 to 0.3 gallons per square yard (gal/yd2) or according to manufacturer’s recommendations.
− Apply solution under pressure. Overlap solution 6 to 12 inches. − Allow treated area to cure for the time recommended by the manufacturer, typically at least 24 hours.
− In low humidities, reactivate chemicals by re-wetting with water at 0.1 to 0.2 gal/yd2 .
Selecting a Soil Binder
Properties of common soil binders used for erosion control are provided in Table 1 and Appendix B.
Use Table 1 to select an appropriate soil binder.
Table 1
Properties of Soil Binders for Erosion Control
Chemicals
Plant Material
Based
(Short Lived)
Plant Material
Based
(Long Lived)
Polymeric
Emulsion
Blends
Cementitious-based
Binders
Relative Cost Low Low Low Low
Resistance to Leaching High High Low to
Moderate
Moderate
Resistance to Abrasion Moderate Low Moderate to
High
Moderate to High
Longevity Short to Medium Medium Medium to Long Medium
Minimum Curing Time before Rain 9 to 18 hours 19 to 24 hours 0 to 24 hours 4 to 8 hours Compatibility with Existing Vegetation Good Poor Poor Poor Mode of Degradation Biodegradable Biodegradable Photodegradabl e/ Chemically
Degradable
Photodegradable/
Chemically Degradable
Labor Intensive No No No No
Specialized Application Equipment Water Truck or
Hydraulic
Mulcher
Water Truck or
Hydraulic
Mulcher
Water Truck or
Hydraulic
Mulcher
Water Truck or Hydraulic
Mulcher
Liquid/Powder Powder Liquid Liquid/Powder Powder
Surface Crusting Yes, but
dissolves on
rewetting
Yes Yes, but
dissolves on
rewetting
Yes
Cleanup Water Water Water Water
Erosion Control Application Rate Varies (1) Varies (1) Varies (1) 4,500 to 13,500 kg/ha (1) Dependent on product, soil type, and slope inclination Temporary Soil Binder SS-5
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Soil Binder SS-5 March 2024 4 of 6
Factors to consider when selecting a soil binder:
■ Suitability to situation – Consider where the soil binder will be applied; determine if it needs a high resistance to leaching or abrasion and whether it needs to be compatible with any existing vegetation. Determine the length of time soil stabilization will be needed and if the soil binder will be placed in an area where it will degrade rapidly. In general, slope steepness is not a discriminating factor for the listed soil binders.
■ Soil types and surface materials – Fines and moisture content are key properties of surface materials. Consider a soil binder’s ability to penetrate, likelihood of leaching, and ability to form a surface crust on the surface materials.
■ Frequency of application – The frequency of application can be affected by subgrade conditions, surface type, climate, and maintenance schedule. Frequent applications could lead to high costs. Application frequency may be minimized if the soil binder has good penetration, low evaporation, and good longevity. Consider also that frequent application will require frequent equipment cleanup.
After considering the above factors, the soil binders in Table 1 will be generally appropriate as follows:
Plant-material Based (Short Lived)
■ Guar: Guar-gum-based tackifier must be derived from the ground endosperm of the guar plant, Cyanmopsis tetragonolobus. It must be treated with dispersing agents for easy mixing. It shall be diluted at the rate of 1 to 5 lb per 100 gallons of water, depending on application machine capacity. Recommended minimum application rates are as follows:
Slope (V:H): Flat 1:4 1:3 1:2 1:1
Kilograms per hectare (kg/ha) 45 50 56 67 78
Pounds per acre (lb/ac) 40 45 50 60 70
■ Psyllium: Psyllium is composed of the finely ground muciloid coating of plantago seeds that is applied as a dry powder or in a wet slurry to the surface of the soil. It dries to form a firm but rewettable membrane that binds soil particles but permits seed germination and growth.
Psyllium requires 12 to 18 hours of drying time. Psyllium shall be applied at a rate of 80 to 200 lb/ac, with enough water in solution to create a uniform slurry flow. ■ Starch: Starch is non-ionic, water soluble granular cornstarch. The material is mixed with water and applied at the rate of 150 lb/ac. Approximate drying time is 9 to 12 hours.
Temporary Soil Binder SS-5
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Soil Binder SS-5 March 2024 5 of 6
Plant-material Based (Long Lived)
■ Pitch and Rosin Emulsion: Generally, a non-ionic pitch and rosin emulsion has a minimum solids content of 48 percent. The rosin shall be a minimum of 26 percent of the total solids content. The soil stabilizer shall be non-corrosive, water-dilutable emulsion that upon application cures to a water-insoluble binding and cementing agent. For soil erosion control applications, the emulsion is diluted and shall be applied as follows:
For clayey soil: 5 parts water to 1 part emulsion
For sandy soil: 10 parts water to 1 part emulsion
Application can be by water truck or hydraulic seeder with the emulsion/ product mixture applied at the rate specified by the manufacturer. Approximate drying time is 19 to 24 hours.
Polymeric Emulsion Blends
■ Acrylic Copolymers and Polymers: Polymeric soil stabilizers shall consist of a liquid or solid polymer or copolymer with an acrylic base that contains a minimum of 55 percent solids. The polymeric compound shall be handled and mixed in a manner that will not cause foaming or shall contain an anti-foaming agent. The polymeric emulsion shall not exceed its shelf life or expiration date; manufacturers shall provide the expiration date. Polymeric soil stabilizer shall be readily miscible in water, non-injurious to seed or animal life, non-flammable, shall provide surface soil stabilization for various soil types without totally inhibiting water infiltration, and shall not re-emulsify when cured. The applied compound shall air cure within a maximum of 36 to 48 hours. Liquid copolymer shall be diluted at a rate of 10 parts water to 1 part polymer and applied to soil at a rate of 1,175 gallons per acre (gal/ac).
■ Liquid Polymers of Methacrylates and Acrylates: This material consists of a tackifier/sealer that is a liquid polymer of methacrylates and acrylates. It is an aqueous 100 percent acrylic emulsion blend of 40 percent solids by volume that is free from styrene, acetate, vinyl, ethoxylated surfactants, or silicates. For soil stabilization applications, it is diluted with water in accordance with manufacturer’s recommendations and applied with a hydraulic seeder at the rate of 20 gal/ac. Drying time is 12 to 18 hours after application. ■ Copolymers of Sodium Acrylates and Acrylamides: These materials are non-toxic, dry powders that are copolymers of sodium acrylate and acrylamide. They are mixed with water and applied to the soil surface for erosion control at rates that are determined by slope gradient Slope Gradient (V:H) kg/ha (lb/ac)
Flat to 1:5 3 to 5
1:5 to 1:3 5 to 10
1:2 to 1:1 10 to 20
■ Polyacrylamide and Copolymer of Acrylamide: Linear copolymer polyacrylamide is packaged as a dry-flowable solid. When used as a stand-alone stabilizer, it is diluted at a rate of 1 lb/100 gal of water and applied at the rate of 5 lb/ac.
Temporary Soil Binder SS-5
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Soil Binder SS-5 March 2024 6 of 6
■ Hydro-Colloid Polymers: Hydro-colloid polymers are various combinations of dry-flowable polyacrylamides, copolymers and hydro-colloid polymers that are mixed with water and applied to the soil surface at rates of 53 to 62 lb/ac. Drying times are 0 to 4 hours.
Cementitious-based Binders
■ Gypsum: This is a formulated gypsum-based product that readily mixes with water and mulch to form a thin protective crust on the soil surface. It is composed of high-purity gypsum that is ground, calcined, and processed into calcium sulfate hemihydrate with a minimum purity of 86 percent. It is mixed in a hydraulic seeder and applied at rates of 4,000 to 12,000 lb/ac. Drying time is 4 to 8 hours.
Additional guidance on the selection of soil stabilization BMPs can be found in Appendix B of this Manual.
Maintenance and Inspection
■ Reapplying the selected soil binder may be needed for proper maintenance. High-traffic areas shall be inspected daily, and lower-traffic areas shall be inspected weekly. ■ A certificate of compliance under Standard Specifications Section 21-2.01C(4) must be submitted to the RE prior to application.
■ It is recommended that a small test area/mock-up occur prior to large-area application to verify sufficient cover for the approved mix.
■ After any rainfall event, the Contractor is responsible for maintaining all slopes to prevent erosion.
■ Maintain an unbroken, temporary stabilized area while DSAs are inactive. Repair any damaged stabilized area and re-apply soil binder to exposed areas. ■ Cleaning of equipment must be done in a designated area that can collect the water to prevent triggering of non-visible and non-stormwater requirements.
SWPPP or WPCP
■ Soil Binders must be discussed in Section 600.1.2 of the SWPPP, or Section 30.2.1 of the WPCP. If non-visible sampling is required, Section 1100 of the SWPPP is also applicable.
SS-6
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Tacked Straw SS-6 March 2024 1 of 3
Temporary Tacked Straw
Definition and Purpose
Temporary tacked straw mulch consists of placing and then incorporating a uniform layer of straw into the soil with a studded roller or anchoring it with a tackifier or rolled erosion control product (RECP). This is one of several temporary soil stabilization alternatives available for consideration.
Appropriate Applications
■ Temporary tacked straw is typically used for soil stabilization and temporary surface cover on disturbed areas until soils can be prepared for revegetation and permanent vegetation is established.
■ Typically used in combination with temporary and/or permanent seeding strategies to enhance plant establishment.
Limitations
Availability of erosion control contractors and straw may be limited prior to rain events due to high demand.
■ The introduction of weed-seed and unwanted plant material is a possibility. ■ Temporary tacked straw applied by hand is more time-intensive and potentially costly. ■ May have to be removed prior to permanent seeding or soil stabilization. ■ “Punching” of straw does not work in sandy soils; a tackifier must be used Standard Symbol
Temporary Tacked Straw SS-6
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Tacked Straw SS-6 March 2024 2 of 3
Standards and Specifications
General Requirements
■ Straw and tackifier must conform to Standard Specifications Sections 21-2.02H, 21.2-03G, and 21-2.02E.
■ A certificate of compliance for straw must be submitted before application. If weed-free straw is used, the certificate of compliance must include the certificate of quarantine compliance. ■ Straw must be derived from wheat, rice, or barley.
■ A tackifier is the preferred method for anchoring straw mulch to the soil on slopes. ■ Selected tackifier must be environmentally benign (non-toxic to plants and animal life) and not pose a threat to water quality.
■ Crimping, “punch” roller-type rollers, or track-walking may be used to incorporate straw mulch into the soil on slopes. Track-walking shall only be used where other methods are impractical. ■ Avoid placing straw onto the traveled way, sidewalks, lined drainage channels, sound walls, and existing vegetation.
■ Temporary tacked straw should not be applied during or immediately before a rain event.
Application Procedures
■ Apply loose straw either by machine or by hand distribution at the rate indicated. ■ Distribute the straw mulch evenly on the soil surface. ■ Straw may be anchored in place by incorporating it into soil or using a tackifier. Additionally, in small areas and/or steep slopes, straw can also be held in place using RECP. Refer to BMP SS-7, “Temporary Cover and Rolled Erosion Control Products.” ■ If a tackifier will be used to anchor the straw in lieu of incorporation, roughen embankment or fill areas by rolling with a crimping or punching-type roller. Track-walking should only be used where rolling is impractical.
■ A tackifier acts to glue the straw fibers together and to the soil surface. Factors influencing tackifier selection include longevity and ability to hold the fibers in place. ■ Apply tackifier according to the manufacturer’s instructed rate for the slope, soil, and wind conditions.
■ If incorporation of straw into soil is the selected method for anchoring, then do as follows:
− Use a spade or shovel to incorporate straw into soil in small areas. − On slopes with soils that are stable enough and of sufficient gradient to safely support construction equipment without contributing to compaction and instability problems, straw can be “punched” into the ground using a knife-blade roller or a straight bladed coulter, known commercially as a “crimper” under Section 21-2.03J of the Standard Specifications.
Temporary Tacked Straw SS-6
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Tacked Straw SS-6 March 2024 3 of 3
Maintenance and Inspections
■ Straw needs to last long enough to achieve erosion control objectives. ■ Maintain an unbroken, temporary mulched ground cover while disturbed soils areas are inactive.
Repair any damaged ground cover and re-mulch exposed areas. ■ Reapplication of straw mulch and tackifier may be required by the RE to maintain effective soil stabilization over disturbed areas and slopes.
■ After any rainfall event, the Contractor is responsible for maintaining all slopes to prevent erosion.
SWPPP or WPCP
■ Temporary tacked straw must be discussed in Section 600.1.2 of the SWPPP or Section 30.2.1 of the WPCP.
SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 1 of 9
Temporary Cover and Rolled Erosion Control
Products
Standard Symbol
Definition and Purpose
This BMP involves the placement of geosynthetics, turf reinforcement mats, plastic covers, or rolled erosion control products (RECPs), including erosion control blankets, to stabilize disturbed soil areas and protect soils from erosion by wind or water. This is one of several temporary soil stabilization alternatives for consideration.
Appropriate Applications
■ These measures are used when disturbed soils may be particularly difficult to stabilize, including the following situations:
− Steep slopes, generally steeper than 3:1 (H:V).
− Slopes with high erosion potential.
− Slopes and disturbed soils where mulch must be anchored. − Disturbed areas where plants are slow to develop.
− Channels with flows exceeding 3 ft/s.
− Channels to be vegetated.
− Slopes adjacent to receiving waters or ESAs.
■ Standards for plastic sheeting used for stockpile covers are provided in Section 14-11.05A of the Standard Specifications.
Temporary Cover and Rolled Erosion
Control Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 2 of 9
Limitations
■ Blankets and mats are typically more expensive than other erosion control measures due to labor and material costs. This usually limits their application to areas inaccessible to hydraulic equipment or where other measures are not applicable, such as channels. ■ May delay seed germination due to reduction in soil temperature. ■ Plastic netting should not be used when regulatory permits prohibit their use or if there is a potential for plastic netting to endanger wildlife.
■ Blankets and mats are generally not suitable for excessively rocky sites or areas where the final vegetation will be mowed (since staples and netting can catch in mowers). ■ Blankets and mats should be removed and disposed prior to application of permanent soil stabilization measures as required by the contract plans. Long-term erosion control blankets must be Class 8 Rock Slope Protection fabric.
■ Plastic sheeting is easily vandalized, easily torn, and photodegradable, and must be disposed at a landfill; it requires extensive inspection and maintenance. ■ Plastic results in 100 percent runoff, which may cause serious erosion problems in the downstream areas receiving the increased flow.
■ The use of plastic should be limited to covering stockpiles or very small, graded areas for short periods (e.g., through one imminent storm event) until alternative measures, such as seeding and mulching, can be installed.
■ Geosynthetics, mats, plastic covers, and RECPs have maximum flow rate limitations; consult the manufacturer for proper selection.
■ Additional guidance for soil stabilization BMP selection is provided in Appendix B of this Manual.
Standards and Specification
Material Selection
■ There are many types of temporary cover material and RECPs, and selection of the appropriate type is based on the specific form of application and site conditions. Selection(s) made by the Contractor must be approved by the Resident Engineer; certification of compliance must be in accordance with Standard Specifications Sections 6-2 and 21-2.01C and 21-2.02O.
Temporary Cover – Geosynthetics
■ Material shall be a woven polypropylene fabric with minimum thickness of 0.06 inches, minimum width of 12 feet, and meet all requirements of Standard Specification Section 96-1 Temporary Cover. Material shall have a minimum tensile strength of 150 lb (warp) and 80 lb (fill) in conformance with the requirements in ASTM Designation D4632. The permittivity of the fabric must be approximately 0.07 sec –1 in conformance with the requirements in ASTM Designation D4491. The fabric must have an ultraviolet stability of 70 percent in conformance with the requirements in ASTM Designation D4355. Geotextile blankets should be secured in place with wire staples or sandbags and by keying into tops of slopes and edges to prevent surface water infiltration. Staples should be made of minimum 16 gauge steel wire and be U-shaped with 8- inch legs and 2-inch crown.
Temporary Cover and Rolled Erosion
Control Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 3 of 9
■ Geotextiles may be reused if, in the opinion of the Resident Engineer, they are suitable for the use intended.
■ Submit a certificate of compliance for each type of geosynthetic material used.
Temporary Cover – Plastic Sheeting
■ Plastic sheeting shall comply with Standard Specification Section 13-5 and 96-1, which require 10-mil-thick, single-ply geomembrane material complying with ASTM Designation D2103 and be keyed in at the top of slope and firmly held in place with one of the following:
− Gravel-filled bags roped together and placed no more than 6 feet apart − Wooden board and steel restrainer. Wood board must be 2 by 4 inches, 8 feet long, and made from fir or pine. Steel reinforcing bars must be spaced not more than 4 feet apart along the wooden board.
− Other weights as authorized by the RE. Seams are typically taped or weighted down their entire length, and there should be at least a 24-inch overlap of all seams. Edges must be embedded a minimum of 6 inches in soil.
■ All sheeting must be inspected periodically after installation and after rain events to check for erosion, undermining, and anchorage failure. Any failures must be repaired immediately. If washout or breakages occur, the material should be re-installed after repairing the damage to the slope or area.
Rolled Erosion Control Products
■ RECPs are typically composed of jute fibers, curled wood fibers, straw, coconut fiber, or a combination of these materials. For a RECP to be considered 100 percent biodegradable, the netting, sewing, or adhesive system that holds the biodegradable mulch fibers together must also be biodegradable.
− Jute mesh is made from a natural fiber that is spun into a yarn then loosely woven into a biodegradable mesh. It is designed to be used in conjunction with vegetation and has longevity of approximately 1 year. The material is supplied in rolled strips that are secured to the soil with steel U-shaped staples. Jute mesh shall comply with all requirements of the jute mesh table included in Standard Specifications Section 21-2. − Erosion control blanket is a machine-produced mat made of processed natural fibers that are bound together to form a continuous matrix surrounded by two natural nets. The processed natural fibers comprising the matrix of the blanket may be a mixture of straw (70 percent) and coconut (30 percent), woven coir (100 percent), or excelsior (curled wood fiber) (80 percent). Erosion control blankets must be furnished in rolled strips a minimum of 72 inches wide and secured in place with steel U-shaped staples. Erosion control blankets must also comply with Section 13-5.02B and 21-2.02O(4) of the Standard Specifications. − Netting consists of pure coconut fibers, or coir, woven into a matrix. Coir netting must be furnished in rolled strips a minimum of 72 to 158 inches wide and 0.3 inches thick. There are three classes of coir netting: Type A, Type B, and Type C. See Section 21-2.02O(3) of the Standard Specifications for the minimum requirements for each type of netting.
Temporary Cover and Rolled Erosion
Control Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 4 of 9
■ Non-biodegradable RECPs are typically composed of polypropylene, polyethylene, nylon, or other synthetic fibers. In some cases, a combination of biodegradable and synthetic fibers is used to construct the RECP. Netting used to hold these fibers together is typically nonbiodegradable as well. Check contract special provisions to determine whether nonbiodegradable products are prohibited based on regulatory requirements. − Turf reinforcement mat is a nondegradable, open-weave textile made of synthetic fibers, filaments, nets, wire mesh, or other elements processed into a permanent three-dimensional matrix. Turf reinforcement mats must be a minimum of 72 inches wide and 0.25 inches thick.
There are three classes of turf reinforcement mat: Type A, Type B, and Type C. See section 21-2.02O(5) of the Standard Specifications for the minimum requirements for each type of netting.
Preparation
■ Proper site preparation is essential to ensure that the products and covers will have complete, direct soil contact. To achieve this, crews must:
− Grade and shape the area of installation.
− Remove all rocks, clods, vegetation or other obstructions larger than 1 inch in size. Fill voids or depressions.
Seeding
■ If applicable, seed the area before RECP installation for erosion control and revegetation. ■ Check all lots and other areas disturbed during installation must be re-seeded. ■ For turf reinforcement mats, seeding is often specified to occur after installation.
Anchoring
■ U-shaped wire staples, metal stake pins, triangular wooden stakes, or fasteners recommended by manufacturers can be used to anchor mats and blankets to the ground surface in conformance with Standard Specifications Section 13-5, 13-6, or 21-2.02R. ■ Staples should be made of minimum 11 gauge steel wire and be U-shaped with 6-inch legs and 1-inch crown.
■ Metal stake pins should be 0.188-inch-diameter steel with a 1.5-inch steel washer at the head of the pin, and 8 inches in length.
■ Wire staples and metal stakes should be driven flush to the soil surface. ■ All anchors should be 6 to 18 inches long and have sufficient ground penetration to resist pullout. Longer anchors may be required for loose soils.
Installation on Slopes
■ Refer to Standard Plans T53 and T54 for details regarding installation on slopes for temporary uses, and H52 for permanent uses.
Temporary Cover and Rolled Erosion
Control Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 5 of 9
Installation in Channels
■ Refer to Standard Plan T55 for details regarding installation in channels. ■ Installation shall be in accordance with the manufacturer’s recommendations.
Soil Filling (if specified for turf reinforcement)
■ Always consult the manufacturer’s recommendations for installation. ■ Do not drive tracked or heavy equipment over mat.
■ Avoid any traffic over matting if loose or wet soil conditions exist. ■ Use shovels, rakes, or brooms for fine grading and touch up. ■ Smooth out soil filling, exposing just the top netting of the mat.
Temporary Soil Stabilization Removal
■ When no longer required for the work, temporary soil stabilization becomes the property of the Contractor.
■ Temporary soil stabilization removed from the work site must be disposed outside the highway right-of-way in conformance with the provisions in Standard Specifications Section 14-10. If approved by the RE, the Contractor may leave the temporary soil stabilizer in place. ■ Caltrans must ensure that only environmentally friendly erosion control BMPs are implemented in the project.
Maintenance and Inspection
Areas treated with temporary soil stabilization must be inspected as specified in the Standard Specifications and special provisions. Areas treated with temporary soil stabilization must be maintained to provide adequate erosion control. Temporary soil stabilization should be reapplied or replaced on exposed soils when an area becomes exposed or exhibits visible erosion. ■ All blankets and mats must be inspected periodically after installation. ■ Installation should be inspected after significant rain events to check for erosion and undermining. Any failures must be repaired immediately. ■ If washout or breakage occurs, re-install the material after repairing the damage to the slope or channel.
SWPPP or WPCP
■ RECP must be discussed in Section 600.1.2 of the SWPPP or Section 30.2.1 of the WPCP.
Temporary Cover and Rolled Erosion Control
Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 6 of 9
Temporary Cover and Rolled Erosion Control
Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 7 of 9
Temporary Cover and Rolled Erosion Control
Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 8 of 9
Temporary Cover and Rolled Erosion Control
Products SS-7
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Cover and Rolled Erosion Control Products SS-7 March 2024 9 of 9
SS-8
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Mulch SS-8
March 2024 1 of 3
Temporary Mulch
Standard Symbol
Definition and Purpose
Temporary mulch consist of applying a mixture of shredded bark, wood chips, or tree trimmings on top of soil. Temporary mulch is mostly applicable to landscape projects.
The primary function of temporary mulch is to reduce erosion by protecting bare soil from rainfall impact, increasing infiltration, and reducing runoff.
Appropriate Applications
■ Temporary mulch is considered a temporary soil stabilization alternative in the following situations:
− As a stand-alone temporary surface cover on disturbed areas until soils can be prepared for revegetation and permanent vegetative cover can be established. − As short-term, non-vegetative ground cover on slopes to reduce rainfall impact, decrease sheet flow velocity, settle out sediment, and reduce wind erosion. − In combination with other BMPs to stabilize roadway embankment slopes and control wind erosion.
Limitations
■ Wood mulch may introduce unwanted vegetation species. ■ Shredded wood does not withstand concentrated flows and is prone to sheet erosion. ■ Green material has the potential for the presence of unwanted weeds and other plant materials.
Delivery system is primarily by manual labor, although pneumatic application equipment is available.
■ Mulch may need to be removed prior to further earthwork.
Temporary Mulch SS-8
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Mulch SS-8
March 2024 2 of 3
■ Mulch should not be used alone to stabilize embankments or sides of swales where concentrated flows could mobilize the material.
Standards and Specifications
Mulch Selection
There are many types of mulches, including tree bark, wood chip, shredded bark, and tree trimming. Selecting the appropriate type should be based on the type of application and site conditions. Before using wood mulches, obtain concurrence with the District Landscape Architect because some mulch used on construction projects may not be compatible with planned or future projects.
Selected wood mulches must comply with Standard Specifications Section 20-5.04 and must be approved by the RE.
Tree Bark Mulch
■ Tree bark mulch must be derived from cedar, Douglas fir, or redwood tree species. ■ Tree bark mulch must be ground such that at least 95 percent of the material by volume is less than 2 inches long in any direction, and no more than 30 percent by volume is less than 1 inch in any direction.
Wood Chip Mulch
■ Wood chip mulch must be derived from clean wood; it may not contain leaves or small twigs. ■ Wood chip mulch must contain at least 95 percent wood chips by volume with a width and thickness from 1/16 to 3/8 inches in any direction and 1/2 to 3 inches in length.
Shredded Bark Mulch
■ Shredded bark mulch must be derived from trees. The mulch must be a blend or loose, long, thin wood or bark pieces.
■ Shredded bark mulch must contain at least 95 percent wood strands by volume with a width and thickness of 1/8 to 1.5 inches in any direction and 2 to 8 inches in length Tree Trimming Mulch
■ Tree trimming mulch is derived from chipped trees and may contain leaves, small twigs, and green material.
■ Tree trimming mulch must contain at least 95 percent material by volume less than 3 inches and no more than 30 percent by volume less than 1 inch.
Application Procedures
■ Do not use soil sterilant or filter fabric.
■ Mulch should be placed uniformly from the outside edge of area designated for mulch.
Permanent landscape mulch should be placed after vegetation has been installed. ■ Mulch may be installed by manual application or with pneumatic devices.
Temporary Mulch SS-8
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Temporary Mulch SS-8
March 2024 3 of 3
■ Do not place mulch within 4 feet of drainage ditch flow lines or other channels or the edge of paved roads.
■ All material must be removed before re-starting work on the slopes.
Maintenance and Inspection
■ Wood mulch needs to last long enough to achieve erosion-control objectives. If the mulch is applied as a stand-alone erosion control method over disturbed areas (without seed), it should last the length of time the site will remain barren or until final re-grading and revegetation.
Additional information is provided in Appendix B of this Manual. ■ Where vegetation is not the ultimate cover, such as ornamental and landscape applications of bark or wood chips, inspection and maintenance should focus on mulch longevity and integrity. ■ May require reapplication when bare soil becomes visible.
SWPPP or WPCP
■ Wood mulch must be discussed in Section 600.1.2 of the SWPPP or Section 30.2.1 of the WPCP.
Construction Site Best Management Practices (BMP) Manual Section 3 3-36
3.2 Temporary Concentrated Flow Conveyance Controls
Temporary concentrated flow conveyance controls consist of a system of measures or BMPs that are used alone or in combination to intercept, divert, convey, and discharge concentrated flows with a minimum of soil erosion, both on site and downstream (off site). Temporary concentrated flow conveyance controls may divert flows around or through the project in a non-erodible fashion.
Temporary concentrated flow conveyance controls include the following BMPs:
• Earth Dikes/Drainage Swales & Lined Ditches
• Outlet Protection/Velocity Dissipation Devices
• Slope Drains
The QSD should evaluate the site conditions and determine if and when diversions are necessary.
Any diversion or additional BMPs for flow conveyance must be described in the SWPPP and shown in in the Water Pollution Control Drawings (WPCDs).
Table 3-1. Temporary Soil Stabilization BMPs
ID BMP Name
SS-1 Scheduling
SS-2 Preservation of Existing Vegetation
SS-3 Temporary Hydraulic Mulch
SS-4 Temporary Hydroseed
SS-5 Temporary Soil Binders
SS-6 Temporary Tacked Straw
SS-7 Temporary Cover and Rolled Erosion Control Products (RECP) SS-8 Temporary Mulch
Temporary Concentrated Flow Conveyance Controls
SS-9 Earth Dikes/Drainage Swales & Lined Ditches
SS-10 Outlet Protection/Velocity Dissipation Devices
SS-11 Slope Drains
SS-12 Streambank Stabilization
The remainder of this section shows the working details for each of the BMPs.
SS-9
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Earth Dikes/Drainage Swales and Lined Ditches SS-9 March 2024 1 of 5
Earth Dikes/Drainage Swales and Lined Ditches
Standard Symbol
Definition and Purpose
These are structures that intercept, divert, and convey surface run-on, generally sheet flow, to prevent erosion.
Appropriate Applications
■ Earth dikes/drainage swales and lined ditches may be used to:
− Convey surface runoff down sloping land.
− Intercept and divert runoff to avoid sheet flow over sloped surfaces. − Divert and direct runoff toward a stabilized watercourse, drainage pipe, or channel. − Intercept runoff from paved surfaces.
■ Earth dikes/drainage swales and lined ditches also may be used:
− Below steep grades where runoff begins to concentrate. − Along roadways and facility improvements subject to flood drainage. − At the top of slopes to divert run-on from adjacent or undisturbed slopes. − At bottom and mid-slope locations to intercept sheet flow and convey concentrated flows.
Limitations
■ Earth dikes/drainage swales and lined ditches are not suitable as sediment trapping devices. ■ May be necessary to use other soil stabilization and sediment controls, such as check dams, plastics, and blankets, to prevent scour and erosion in newly graded dikes, swales and ditches.
Earth Dikes/Drainage Swales and
Lined Ditches SS-9
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Earth Dikes/Drainage Swales and Lined Ditches SS-9 March 2024 2 of 5
■ Temporary swales and ditches, nor any other runoff diversion device, should not adversely impact upstream or downstream properties.
Standards and Specifications
■ Standard Specification Section 19-6 “Embankment Construction,” which covers allowable materials and construction procedures for dikes.
■ Standard Specification Section 72-5 “Concrete Slope Protection, Gutter, Ditch and Channel Lining” covers ditch and channel lining materials and construction procedures. ■ Care must be applied to correctly size and locate earth dikes, drainage swales, and lined ditches. Excessively steep, unlined dikes and swales are subject to erosion and gully formation. ■ Must complete a careful evaluation of the risks due to erosion of the selected measure based on flow velocity, soil types, potential for over topping, flow backups, washouts, and drainage patterns for each BMP location.
■ Conveyances shall be stabilized. Consider using a lined ditch for high flow velocities to prevent scour. Compact any fills or backfills to prevent unequal settlement. ■ Do not divert runoff from the highway right-of-way onto other property. ■ When possible, install and use permanent dikes, swales, and ditches early in the construction process.
■ Earthen berms should be 8 inches tall and 36 inches wide at a minimum. Earthen berms must be compacted either by hand or mechanical methods.
■ Provide stabilized outlets. Refer to SS-10, “Outlet Protection/Velocity/ Dissipation Devices.” Maintenance and Inspections
At a minimum, perform inspections weekly, prior to forecasted rain events, daily during extended rain events, and after the conclusion of rain events ■ Inspect ditches and berms for washouts. Replace lost riprap, damaged linings, or soil stabilizers as needed.
■ Inspect channel linings, embankments, and beds of ditches and berms for erosion and accumulation of debris and sediment.
■ Remove debris and sediment, and repair linings and embankments to ensure they function as intended.
■ Temporary conveyances should be completely removed as soon as the surrounding drainage area has been stabilized or at the completion of construction.
SWPPP or WPCP
■ Earth Dikes/Drainage Swales and Lined Ditches must be discussed in Section 600.1.1 and 600.1.2 of SWPPP or Section 30.2.1 of the WPCP
Earth Dikes/Drainage Swales and Lined Ditches SS-9
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Earth Dikes/Drainage Swales and Lined Ditches SS-9 March 2024 3 of 5
Earth Dikes/Drainage Swales and Lined Ditches SS-9
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Earth Dikes/Drainage Swales and Lined Ditches SS-9 March 2024 4 of 5
Earth Dikes/Drainage Swales and Lined Ditches SS-9
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Earth Dikes/Drainage Swales and Lined Ditches SS-9 March 2024 5 of 5
SS-10
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Outlet Protection/Velocity Dissipation Devices SS-10 March 2024 1 of 2
Outlet Protection/Velocity Dissipation Devices
Definition and Purpose
These devices are placed at pipe outlets to prevent scour and reduce the velocity and/or energy of stormwater flows.
Appropriate Applications
These devices may be used at the following locations:
■ Outlets of pipes, drains, culverts, slope drains, diversion ditches, swales, conduits, or channels. − Outlets located at the bottom of mild to steep slopes. − Discharge outlets that carry continuous flows of water. − Outlets subject to short, intense flows of water, such as flash floods. − Points where lined conveyances discharge to unlined conveyances.
Limitations
■ Loose rock may have stones washed away during high flows. ■ Grouted rock slope protection may break up in areas of freeze and thaw. ■ If there is not adequate drainage and water builds up behind grouted rock slope protection, it may cause the grouted rock slope protection to break up due to the resulting hydrostatic pressure.
■ Outlet protection may negatively impact the channel habitat.
Standard Symbol
Outlet Protection/Velocity
Dissipation Devices SS-10
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Outlet Protection/Velocity Dissipation Devices SS-10 March 2024 2 of 2
Standards and Specifications
■ There are many types of energy dissipaters; a flared end section and rock slope protection is shown in the photo on the previous page. Please note that this is only one example, and the RE may approve other types of devices proposed by the Contractor. ■ Flared end sections must comply with Standard Specifications Section 70-5.02. ■ Rock slope protection must comply with Standard Specifications Section 72. ■ Install rock slope protection, grouted rock slope protection, or concrete apron at selected outlet.
Rock slope protection aprons are best suited for temporary use during construction. ■ Carefully place rock slope protection to avoid damaging the filter fabric. ■ For proper operation of the apron:
− Align apron with receiving stream and keep it straight throughout its length. If a curve is needed to fit site conditions, consider placing it in the upper section of the apron. − If the apron rock slope protection area is large, consider protecting underlying filter fabric with a gravel blanket.
■ Outlets on slopes steeper than 10% should have additional protection.
Maintenance and Inspection
■ At a minimum, perform inspections weekly, prior to forecasted rain events, daily during extended rain events, and after the conclusion of rain events. ■ Minimize areas of standing water by removing sediment blockages and filling scour depressions. If persistent, it might be necessary to have a licensed professional re-evaluate the size and type of device implemented.
■ Inspect apron for displacement of the rock slope protection and/or damage to the underlying fabric. Repair fabric and replace rock slope protection that has washed away. ■ Inspect for scour beneath the rock slope protection and around the outlet. Repair damage to slopes or underlying filter fabric immediately.
■ Temporary devices should be completely removed as soon as the surrounding drainage area has been stabilized, or at the completion of construction.
SWPPP or WPCP
■ Outlet protection/Velocity dissipation devices must be discussed in Section 600.1.1 and 600.1.2 of SWPPP or Section 30.2.1 of the WPCP.
SS-11
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Slope Drains SS-11
March 2024 1 of 2
Slope Drains
Definition and Purpose
A slope drain is a pipe used to intercept and direct surface runoff or groundwater into a stabilized watercourse, trapping device, or stabilized area. Slope drains are used with lined ditches to intercept and direct surface flow away from slope areas to protect cut or fill slopes.
Appropriate Applications
■ On construction sites where slopes may be eroded by surface runoff. ■ As drainage for top of slope dikes or swales.
■ As drainage for top of cut-and-fill slopes where water can accumulate. ■ As an emergency spillway for a sediment basin.
Limitations
■ Severe erosion may result when slope drains fail by overtopping, piping, or pipe separation. ■ Sediment accumulation, scour depressions, and/or persistent non-stormwater discharges in energy dissipaters associated with slope drain outlets can result in suitable areas for vector production.
Standards and Specifications
■ Maximum slope generally limited to 2:1 (H:V), as energy dissipation below steeper slopes is difficult.
■ Direct surface runoff to slope drains with interceptor dikes. See BMP SS 8, “Earth Dikes/Drainage Swales, and Lined Ditches.”
Standard Symbol
Slope Drains SS-11
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Slope Drains SS-11
March 2024 2 of 2
■ Slope drains can be placed on or buried underneath the slope surface. ■ Recommended materials are plastic or corrugated metal, or comparable pipe. ■ When installing slope drains:
− Install slope drains perpendicular to slope contours. − Compact soil around and under entrance, outlet, and along length of pipe. − Securely anchor and stabilize pipe and appurtenances into soil. − Check to ensure that pipe connections are watertight. − Protect area around inlet with filter cloth. Protect outlet with rock slope protection or other energy-dissipation device. For high-energy discharges, reinforce rock slope protection with concrete or use reinforced concrete device.
− Protect inlet and outlet of slope drains; use standard flared-end section at entrance and exit for pipe slope drains 12 inches and larger.
Maintenance and Inspection
■ Inspect weekly during construction duration, and prior to forecasted rain events, daily during extended rain events, and after the conclusion of qualifying precipitation events. Inspect outlet for erosion and downstream scour.
■ If eroded, repair damage and install additional energy-dissipating measures. If downstream scour is occurring, it may be necessary to reduce flows being discharged into the channel. ■ Inspect slope drainage for accumulations of debris and sediment. ■ Remove built-up sediment from entrances, outlets, and within drains as required. ■ Make sure stormwater is not ponding onto inappropriate areas (e.g., active traffic lanes, material storage areas, etc.).
SWPPP or WPCP
■ Slope drains must be discussed in Sections 600.1.1 and 600.1.2 of SWPPP or Section 30.2.1 of the WPCP.
SS-12
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Streambank Stabilization SS-12 March 2024 1 of 5
Streambank Stabilization
Standard Symbol
Definition and Purpose
Drainage systems, including the stream channel, streambank, and associated riparian areas, are dynamic and sensitive ecosystems that respond to changes in land use activity. Streambank and channel disturbance resulting from construction activities can increase the stream’s sediment load, which can cause channel erosion or sedimentation and have adverse affects on the biotic system.
BMPs can reduce the discharge of sediment and other pollutants and minimize the impact of construction activities on watercourses. Streams included on the 303(d) list by the State Water Resources Control Board (SWRCB) may require careful evaluation to prevent any increases in sedimentation, siltation, and/or turbidity to the stream.
Appropriate Applications
These procedures typically apply to all construction projects that disturb or occur within stream channels and their associated riparian areas. Streambank stabilization typically consists of a combination of several BMPs to prevent destabilization and enhance stability of eroding streambanks.
Limitations
Specific permit requirements or mitigation measures such as Regional Water Quality Control Board 401 Certification, U.S. Army Corps of Engineers 404 Permit, and approval by California Department of Fish and Wildlife Service may be included in Contract Documents. Specific requirements could include in-water work windows, vegetation species, seed mixes, stabilization measures, water quality monitoring protocols and specific reporting requirements. If numerical-based water quality standards are mentioned in any of these and other related permits, testing and sampling may be required. Streams included on the 303(d) list by the SWRCB because of sediment, silt, or turbidity impairment are required to conduct sampling to verify that there is no net increase in sediment load due to construction activities.
Streambank Stabilization SS-12
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Streambank Stabilization SS-12 March 2024 2 of 5
Standards and Specifications
PLANNING
■ Proper planning, design, and construction techniques can minimize impacts normally associated with in-stream construction activities. Poor planning can adversely affect soil, fish, and wildlife resources, land uses, or land users. Planning should take into account scheduling, avoidance of in-stream construction, minimizing disturbance area and construction time period, using predisturbed areas, selecting crossing location, and selecting equipment and proper stabilization techniques once the activity is completed.
Scheduling (SS-1)
■ Construction activities should be scheduled according to the relative sensitivity of the environmental concerns and in accordance with SS-1, “Scheduling.” Scheduling considerations will be different when working near perennial streams vs. ephemeral streams and are as follows:
− Construction work near perennial streams should optimally be performed during the dry season (see below).
− When working in or near ephemeral, intermittent, or perennial streams, construction should be performed during the dry season and in accordance with regulatory agency permits and approvals. By their very nature, ephemeral and intermittent streams are usually dry in the summer, and therefore in-stream construction activities will not cause significant water quality problems. For perennial streams, clear water diversion (see NS-5 for “Clear Water Diversion”), dewatering (see NS-2 for “Dewatering Operations”) and water quality monitoring may be required.
− When closing the site at the end of the job, wash any fines that were formed in situ back into the channel bed material to decrease pollution from the first rainstorm (first flush) of the season. When working near stream channels, erosion and sediment controls (e.g., silt fences, straw bale barriers, etc.) should be implemented on the banks to keep sediment out of the stream channel.
− Regulatory permits might require or allow for the stockpiling of native bed material to be backfilled during stabilization.
Minimize Disturbance
■ Minimize disturbance by selecting the narrowest crossing location, limiting the number of equipment trips across a stream during construction, and minimizing the number and size of work areas (e.g., equipment staging areas and spoil storage areas). Provide stabilized access to the stream when in-stream work is required. Field reconnaissance should be conducted during the planning stage to identify work areas.
■ Comply with regulatory permit requirements, if none are applicable, place work areas (e.g., stage area, active construction) at least 50 feet from the stream channel. Perform each of the following activities at least 100 feet from a drainage course if it is performed within the floodplain, or at least 50 feet outside the floodplain: stockpiling materials, storing pile-driving equipment and liquid waste containers, washing vehicles and equipment, and fueling and maintaining vehicles and equipment.
Streambank Stabilization SS-12
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Streambank Stabilization SS-12 March 2024 3 of 5
■ Locate access and staging areas in paved or pre-disturbed areas when possible. If not possible, select access and staging areas that minimize disturbance to aquatic species, riparian vegetation, and habitat.
■ Avoid steep and unstable banks, highly erodible or saturated soils, or highly fractured rock, wherever possible.
■ Select equipment that reduces the amount of pressure exerted on the ground surface and therefore reduces erosion potential, and/or use overhead or aerial access for transporting equipment across drainage channels. Use equipment that exerts ground pressures of less than 5 or 6 pounds per square inch where possible. Low ground pressure equipment includes wide or high flotation tires (34 to 72 inches wide), dual tires, bogie axle systems, tracked machines, lightweight equipment, and central tire inflation systems.
STREAMBANK STABILIZATION
Preservation of Existing Vegetation (SS-2)
■ Preserve existing vegetation in accordance with SS-2, “Preservation of Existing Vegetation.” In a streambank environment, preservation of existing vegetation provides the following benefits:
Water Quality Protection
Vegetated buffers on slopes trap sediment and promote groundwater recharge. The buffer width needed to maintain water quality ranges from 15 to 100 feet. On gradual slopes, most of the filtering occurs within the first 30 feet of the buffer. Steeper slopes require a greater width of vegetative buffer to provide water quality benefits.
Streambank Stabilization
The root system of riparian vegetation stabilizes streambanks by increasing tensile strength in the soil. The presence of vegetation modifies the moisture condition of slopes (e.g., infiltration, evapotranspiration, interception) and increases bank stability.
Riparian Habitat
Buffers of diverse riparian vegetation provide food, shelter, and shade for riparian and aquatic organisms. Minimizing impacts to fisheries habitat is a major concern when working near streams and rivers. Riparian vegetation provides shade, shelter, organic matter (leaf detritus and large woody debris), and other nutrients that are necessary for fish and other aquatic organisms. Buffer widths for habitat concerns are typically wider (100 to 1,500 feet) than those recommended for water quality concerns.
When working near watercourses, it is important to understand the work site’s placement in the watershed. Riparian vegetation in the headwater streams has a greater impact on overall water quality than vegetation in downstream reaches. Preserving existing vegetation in upstream areas is necessary to maintain water quality, minimize bank failure, and maximize riparian habitat downstream of the work site.
■ Local county and municipal ordinances regarding width, extent, and type of vegetative buffer required may exceed the specifications provided here; these ordinances should be investigated prior to construction.
■ As a general rule, the width of a buffer strip between a road and the stream is recommended to be 50 feet plus four times the percent slope of the land, measured between the road and the top of stream bank.
Streambank Stabilization SS-12
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Streambank Stabilization SS-12 March 2024 4 of 5
Temporary Hydraulic Mulch (SS-3), Temporary Hydroseed (SS-4), and Temporary Soil Binder (SS-5)
■ Apply hydraulic mulch, hydroseed, or soil binders on disturbed streambanks above the mean high water level to provide temporary soil stabilization. ■ Do not place hydraulic mulch, tackifiers, fertilizers, or soil binders below the mean high water level, as these materials could wash into the channel and impact water quality or possibly cause eutrophication.
Straw Mulch (SS-6)
■ Apply straw mulch to disturbed streambanks in accordance with SS-6, “Temporary Tacked Straw.”
■ Do not place straw mulch or tackifiers below the mean high water level, as this material could wash into the channel and impact water quality.
Temporary Cover and Rolled Erosion Control Products (SS-7) ■ Install geosynthetics, rolled erosion control product, and plastic as described in SS-7, “Temporary Cover and Rolled Erosion Control Products” to stabilize disturbed channels and streambanks.
■ Not all applications of SS-7 should be installed in a channel. For example, certain geotextile netting may snag fish gills and are not appropriate in fish-bearing streams. Geotextile fabrics that are not biodegradable are not appropriate for in-stream use. Additionally, geotextile fabric or blankets placed in channels must be adequate to sustain anticipated hydraulic forces.
Earth Dikes/Drainage Swales, and Lined Ditches (SS-9)
■ Convey, intercept, or divert runoff from disturbed streambanks using SS-9, “Earth Dikes/Drainage Swales, and Lined Ditches.”
■ Do not place earth dikes in watercourses, as these structures are only suited for intercepting sheet flow and should not be used to intercept concentrated flow.
Outlet Protection/Velocity Dissipation Devices (SS-10)
■ Place outlet protection or velocity dissipation devices at outlets of pipes, drains, culverts, slope drains, diversion ditches, swales, conduits, or channels in accordance with SS-10.
Slope Drains (SS-11)
■ Use slope drains to intercept and direct surface runoff or groundwater into a stabilized watercourse, trapping device, or stabilized area in accordance with SS-11, “Slope Drains.” The use of slope drains minimizes potential streambank erosion from overland flows.
STREAMBANK SEDIMENT CONTROL
Temporary Silt Fences (SC-1)
■ Install silt fences in accordance with SC-1, “Temporary Silt Fence” to control sediment. Silt fences should only be installed where sediment-laden water can pond, thus allowing the sediment to settle out.
Streambank Stabilization SS-12
Caltrans Stormwater Quality Handbooks Section 3
Construction Site BMP Manual Streambank Stabilization SS-12 March 2024 5 of 5
Temporary Fiber Rolls (SC-5)
■ Install fiber rolls in accordance with SC-5, “Temporary Fiber Rolls” along slope contour above the high water level to intercept runoff, reduce flow velocity, release the runoff as sheet flow, and remove sediment from the runoff. In a stream environment, fiber rolls should be used in conjunction with other sediment control methods such as SC-1, “Silt Fence” or SC-9, “Straw Bale Barrier.” Install silt fence, straw bale barrier, or other erosion control methods along the toe of slope above the high water level.
Temporary Gravel Bag Berm (SC-6)
■ A gravel bag berm or barrier can be used to intercept and slow the flow of sediment-laden sheet flow runoff in accordance with SC-6, “Temporary Gravel Bag Berm.” In a stream environment, gravel bag barriers can allow sediment to settle from runoff before water leaves the construction site and can be used to isolate the work area from the stream. Gravel bag barriers are not recommended as a perimeter sediment control practice around streams.
Temporary Straw Bale Barrier (SC-9)
■ Install straw bale barriers in accordance with SC-9, “Temporary Straw Bale Barrier” to control sediment. Straw bale barriers should only be installed where sediment-laden water can pond, thus allowing the sediment to settle out. Install a silt fence in accordance with SC-1, “Silt Fence” on the down-slope side of the straw bale barrier closest to the stream channel to provide added sediment control.
Temporary Compost Sock (SC-08)
■ Compost socks are a mesh sock containing compost that acts as three-dimensional, biodegradable structures that intercept and filter sheet flow. Compost socks can filter runoff, retain sediment, and reduce sheet flow velocities. Compost may be pre-seeded to assist in vegetation establishment. Compost socks may be used as either a temporary or permanent sediment control measure.
Inspection and Maintenance
■ Inspect BMPs daily during construction.
■ Maintain and repair BMPs.
■ Remove accumulated sediment as necessary.
SWPPP or WPCP
■ Streambank stabilization must be discussed in Section 600.1.1 and 600.1.2 of the SWPPP or Section 30.2.1 of the WPCP.
4-1
Section 4
Temporary Sediment Control BMP
4.1 Temporary Sediment Controls
Temporary sediment controls include those practices that intercept and slow or detain the flow of stormwater to allow sediment to settle and be trapped. These practices can consist of installing temporary linear sediment barriers (such as temporary silt fences, sandbag barriers, and temporary straw bale barriers); providing temporary fiber rolls, temporary gravel bag berms, or temporary check dams to break up slope length or flow; or constructing a temporary sediment/desilting basin on sediment trap. Linear sediment barriers are typically placed below the toe of exposed and erodible slopes, downslope of exposed soil areas, around temporary stockpiles, and at other appropriate locations along the site perimeter.
Temporary sediment control practices must be implemented in conformance with the criteria presented in Section 2 of this Manual and the SWPPP/WPCP Preparation Manual. Temporary sediment control practices include the BMPs listed in Table 4-1.
Table 4-1. Temporary Sediment Control BMPs
ID BMP Name
SC-1 Temporary Silt Fence
SC-2 Sediment/Desilting Basin
SC-3 Sediment Trap/Curb Cutback
SC-4 Temporary Check Dam
SC-5 Temporary Fiber Rolls
SC-6 Temporary Gravel Bag Berm/Earthen Berm
SC-7 Street Sweeping
SC-8 Sandbag Barrier
SC-9 Temporary Straw Bale Barrier
SC-10 Temporary Drainage Inlet Protection
SC-11 Temporary Compost Sock
SC-12 Flexible Sediment Barrier
The remainder of this section describes the working details for each of the temporary sediment control BMPs.
SC-1
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Silt Fence SC-1
March 2024 1 of 6
Temporary Silt Fence
Standard Symbol
Definition and Purpose
A silt fence is a temporary linear sediment barrier of permeable fabric designed to intercept and slow the flow of sediment-laden sheet flow runoff. Silt fences allow sediment to settle from runoff before water leaves the construction site.
Appropriate Applications
■ Below the toe of exposed and erodible slopes.
■ Down-slope of exposed soil areas.
■ Around temporary stockpiles.
■ Along streams and channels.
■ Along the perimeter of a project.
Limitations
■ Not effective unless trenched and keyed in.
■ Not intended for use as mid-slope protection on slopes greater than 4:1 (H:V). ■ Must be maintained.
■ Must be removed and disposed.
■ Do not use below slopes subject to creep, slumping, or landslides. ■ Do not use in streams, channels, drain inlets, or anywhere flow is concentrated. ■ Do not use silt fences to divert flow.
■ Do not use in locations where ponded water may cause a flooding hazard.
Temporary Silt Fence SC-1
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Silt Fence SC-1
March 2024 2 of 6
Standards and Specifications
Design and Layout
■ The drainage area above any fence should not exceed a quarter of an acre, (100 feet of silt fence per 10,000 square feet of DSA).
■ Slope of area draining to silt fence should be less than 1:1 (H:V). ■ Silt fences must be placed parallel to the slope contour. ■ Silt fences rely on temporary ponding to encourage sediment deposition and achieve water quality benefits. Limit application to areas where ponding and deposition may occur on the uphill side of the silt fence.
■ Temporary silt fence fabrics generally have life spans ranging between 5 and 8 months.
Projects with longer durations may require replacing silt fence fabric. ■ Silt fences constructed across concentrated flows are susceptible to washout. Silt fences shall not be installed across concentrated flows.
■ For slopes adjacent to water bodies or environmentally sensitive areas (ESA), additional temporary soil stabilization BMPs should be used.
■ For any 50-foot section of silt fence, the elevation of the base of the fence may not vary by more than 1/3 of the fence height.
■ Install along a level contour to prevent water ponding more than 1.5 feet at any point along the silt fence.
■ Join separate sections to form reaches not more than 500 feet without openings. Ensure there are no gaps between posts.
Reinforced Silt Fence
■ Temporary reinforced silt fence is typically used in areas affected by high winds. They are also often used on slopes steeper than 2:1 (H:V) that contain a high number of rocks or large dirt clods that tend to dislodge, or where area draining fence contains moderate sediment loads. ■ Temporary reinforced silt fence (type 2) may also be used to provide sediment control and delineate ESAs.
Materials
■ Silt fence fabric should be a woven or unwoven geosynthetic textile that complies with Section 96-1.02E of the Standard Specifications. The Contractor must submit a certificate of compliance for silt fence fabric in accordance with Standard Specifications Section 6-2.03C. ■ Wood posts should be untreated fir, redwood, cedar, or pine lumber. Each silt fence post should be at least 4 feet long, except reinforced silt fence posts, which should be at least 6 feet for Type 1 and 5 feet for Type 2 installations. Posts should be free from decay, splits, or cracks longer than the thickness of the post or other defects that would weaken the posts and cause the posts to be structurally unsuitable. Steel posts may be used as well. Posts should comply with the requirements in Standard Specifications sections 16-2.03B and 13-10.02C. ■ Anchors may be used. Anchors consist of a number 4 steel reinforcing bar. End protection shall be provided for any exposed bar reinforcement.
Temporary Silt Fence SC-1
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Silt Fence SC-1
March 2024 3 of 6
■ Staples used to fasten the fence fabric to the posts and to join adjacent silt fence sections shall be U-shaped and have 1/2-inch legs and a 1-inch crown. Staples should be 1/16-inches in diameter. At least four staples should be installed on each silt fence post for adequate fastening, with a maximum of 8 inches between each staple.
Installation
■ Install in accordance with pages 5 and 6 of Standard Plans T51 “Temporary Silt Fence” and T60 “Temporary Reinforced Silt Fence”.
■ Generally, silt fences should be used in conjunction with soil stabilization source controls up slope to provide effective erosion and sediment control. ■ Excavate a trench that is 6 inches deep and 6 inches wide with a length consistent with the project design plans. Place the bottom of the silt fence fabric in the trench. Backfill the trench with soil over the base of the silt fence fabric. Compact the backfill soil by hand or mechanical methods.
■ Construct the length of each reach so that the change in base elevation along any 50-foot reach does not exceed 1/3 the height of the barrier; in no case should any reach of temporary silt fence exceed 500 feet in length.
■ Construct silt fences with a set-back of at least 3 feet from the toe of a slope. Where a silt fence is determined to be not practical with a 3-foot set-back from the toe due to specific site conditions, the silt fence may be constructed at the toe of the slope, but as far from the toe of the slope as practical.
Maintenance and Inspection
■ Repair undercut silt fences.
■ Repair or replace split, torn, slumping, or weathered fabric. ■ Inspect silt fence when rain is forecasted. Perform necessary maintenance, or maintenance required by the Engineer.
■ Inspect silt fence following rain events. Perform maintenance as necessary, or as required by the Engineer.
■ Maintain silt fences to provide an adequate sediment-holding capacity. Sediment should be removed when the sediment accumulation reaches 1/3 of the barrier height. ■ Silt fences that are damaged and become unsuitable for the intended purpose should be removed from the site of work, disposed outside the highway right of way in conformance with the Standard Specifications, and replaced with new silt fence barriers. ■ Holes, depressions, or other ground disturbance caused by the removal of the temporary silt fences should be backfilled and repaired in conformance with the Standard Specifications. ■ Remove silt fence when no longer needed. Fill and compact post holes and anchorage trench, remove sediment accumulation, and grade fence alignment to blend with adjacent ground. ■ Silt fence placement is to be shown in the WPCDs along with other BMPs.
Temporary Silt Fence SC-1
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Silt Fence SC-1
March 2024 4 of 6
SWPPP or WPCP
■ Temporary silt fence or reinforced silt fence must be discussed in Section 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP.
Temporary Silt Fence SC-1
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Silt Fence SC-1
March 2024 5 of 6
Temporary Silt Fence SC-1
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Silt Fence SC-1
March 2024 6 of 6
SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 1 of 9
Sediment/Desilting Basin
Standard Symbol
Definition and Purpose
A sediment/desilting basin is a temporary basin formed by excavating and/or constructing an embankment so that sediment-laden runoff is temporarily detained under quiescent conditions, which allows sediment to settle out before the runoff is discharged (refer to Figures 1 through 4).
Appropriate Applications
Sediment basins shall be designed in accordance with the State of California NPDES General Permit for Storm Water Discharges Associated with Construction Activities (CGP). If there is insufficient area to construct a sediment basin in accordance with the CGP requirements, then the alternate desilting design standards specified herein may be used as approved by the RE.
Sediment/Desilting basins should be considered for use:
■ On construction projects with disturbed soil areas (DSA) during the wetter months, typically October through May.
■ Where sediment-laden water may enter the drainage system or watercourses. ■ At drainage outlets of DSAs (with areas between 5 and 10 acres (ac)).
Limitations
■ Alternative BMPs must be thoroughly investigated for erosion control before selecting temporary sediment/desilting basins.
■ Requires large surface areas to permit sediment settling. ■ Size may be limited by availability of right-of-way.
■ Not appropriate for drainage areas greater than 75 ac.
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 2 of 9
■ Not to be located in live streams.
■ For safety reasons, basins should have protective fencing. ■ Not to be used as a standalone BMP; it requires proper BMP implementation upstream and downstream of its location.
Standards and Specifications
General Requirements
■ Sediment basins should be designed in accordance with the methods referenced in the CGP. ■ Areas under embankments, structural works, and sediment basin must be cleared and stripped of vegetation in accordance with Standard Specifications Section 16 – “Temporary Facilities.” ■ Earthwork should be in accordance with Standard Specifications Section 19 – “Earthwork.” Contractor is specifically directed to Standard Specifications Sections 19-5, “Compaction,” and 19-6, “Embankment Construction.”
■ Chain-link fencing should be provided around each sediment basin to prevent unauthorized entry to the basin or if safety is a concern. Fencing should be in accordance with Standard Specifications Section 80 – “Fences.”
■ This BMP may be implemented on a project-by-project basis with other BMPs when determined necessary and feasible by the RE.
■ The outflow from the basins must have outlet protection to prevent erosion and scouring of the embankment and channel. See BMP SS-10, “Outlet Protection/Velocity Dissipation Devices.” ■ Avoid dewatering of groundwater to the sediment basin during the wetter months. Insignificant quantities of accumulated precipitation may be dewatered to the sediment basin unless precipitation is forecasted within 24 hours. Refer to NS-2, “Dewatering.” Other Considerations
■ Basin should be located: (1) by excavating a suitable area or where a low embankment can be constructed across a swale, (2) where post-construction (permanent) detention basins will be constructed, (3) where failure would not cause loss of life or property damage, (4) where the basins can be maintained on a year-round basis to provide maintenance access for sediment removal and stockpiling in a protected area, and to maintain required capacity. ■ Construct sediment basins prior to the rainy season and construction activities. ■ Sediment basins, regardless of size and storage volume, should include features to accommodate overflow or bypass flows that exceed the design storm event. The calculated basin volume and proposed location should be submitted to the RE for approval at least 3 days prior to basin construction.
■ Construct an emergency spillway to accommodate flows not carried by the principal spillway.
Spillway should consist of an open channel (earthen or vegetated) over undisturbed material (not fill) or constructed of a non-erodible rock slope protection. ■ The spillway control section, which is a level portion of the spillway channel at the highest elevation in the channel, should be a minimum of 20 feet (ft) long.
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 3 of 9
■ Limit the contributing area to the sediment basin to only the runoff from DSAs. Use temporary concentrated flow conveyance controls to divert runoff from undisturbed areas away from the sediment basin.
■ A forebay constructed upstream of the basin may be provided to allow debris and larger particles to settle out of suspension before entering the basin. ■ Basin inlets should be located to maximize travel distance to the basin outlet and resulting sediment deposition benefits.
■ Rock or vegetation should be used to protect the basin inlet and slopes against erosion. ■ The outlet structure should be placed on a firm, smooth foundation with the base securely anchored with concrete or other means to prevent floatation. ■ Discharge from the basin should be accomplished through a water quality outlet. An example is shown in Figure 3. The principal outlet should consist of a corrugated metal, high-density polyethylene (HDPE), or reinforced concrete riser pipe. The outlet should have dewatering holes and an anti-vortex device and trash rack attached to the top of the riser to prevent floating debris from flowing out of the basin or obstructing the system. This principal structure should be designed to accommodate the inflow design storm.
■ A rock pile or rock-filled gabions can serve as alternatives to the debris screen, although the designer should be aware of the potential for extra maintenance involved should the pore spaces in the rock pile clog.
■ Proper hydraulic design of the outlet is critical to achieving the desired basin performance. The water quality outlet should be designed to drain the basin within 24 to 96 hours (also referred to as drawdown time; the 24-hour limit is specified to provide adequate settling time; the 96-hour limit is specified to avoid vector control concerns). Local agencies may have more stringent drawdown time requirements.
■ The two most common outlet problems that occur are: (1) the capacity of the outlet is too great and results in only partial basin filling and drawdown time that is less than designed for; and (2) the outlet clogs because it is not adequately protected against trash and debris. To avoid these problems, the following outlet types are recommended: (1) a single orifice outlet with or without the protection of a riser pipe, and (2) a perforated riser. Design guidance for single orifice and perforated riser outlets are:
■ Flow Control Using a Single Orifice At The Bottom Of The Basin (see Figure 1).
The outlet control orifice should be sized using the following equation:
■
Where:
a = area of orifice (ft2
) (1 ft2 =0.0929m2)
A = surface area of the basin at mid elevation (ft2
)
C = orifice coefficient
T = drawdown time of full basin (hrs)
G = gravity (32.2 ft/s2
)
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 4 of 9
H = elevation when the basin is full (ft)
Ho = final elevation when basin is empty (ft)
With a drawdown time of 40 hours, the equation becomes:
■ Flow Control Using Multiple Orifices (see Figure2):
With terms as described above except:
at = total area of orifices
hmax = maximum height from lowest orifice to the maximum water surface (ft) hcentroid of orifices =height from the lowest orifice to the centroid of the orifice configuration (ft) Allocate the orifices evenly on two rows; separate the holes by 3x hole diameter vertically, and by 120 degrees horizontally (refer to Figure 3).
Because basins are not maintained for infiltration, water loss by infiltration should be disregarded when designing the hydraulic capacity of the outlet structure.
Care must be taken in the selection of “C”; 0.60 is most often recommended and used; however, based on actual tests, (GKY, 1989), "Outlet Hydraulics of Extended Detention Facilities for Northern Virginia Planning District Commission,” recommends either of the following:
C = 0.66 for thin materials, where the thickness is equal to or less than the orifice diameter C = 0.80 when the material is thicker than the orifice diameter ■ The Contractor should verify that the outlet is properly designed to handle the design and peak flows.
■ If rock is used for energy dissipation or to prevent erosion it must comply with Highway Design Manual Chapter 860.
■ Attach riser pipe (watertight connection) to a horizontal pipe (barrel) that extends through the embankment to toe of fill. Provide anti-seep collars on the barrel. ■ Cleanout level should be clearly marked on the riser pipe. ■ Basins with an impounding levee greater than 5 ft tall measured from the lowest point to the impounding area to the highest point of the levee, and basins capable of impounding more than 35,300 cubic ft, should be designed by a professional Civil Engineer registered with the state of California. The design must be submitted to the RE for approval at least 7 days prior to the basin construction. The design should include maintenance requirements, including sediment and vegetation removal, to ensure continuous function of the basin outlet and bypass structures.
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 5 of 9
Maintenance and Inspection
■ Inspect sediment basins before and after rainfall events and weekly year-round. During extended rainfall events, inspect at least every 24 hours. ■ Examine basin banks for seepage and structural soundness. ■ Check inlet and outlet structures and spillway for any damage or obstructions. Repair damage and remove obstructions as needed.
■ Remove standing water from the basin within 72 hours after accumulation. ■ Check inlet and outlet area for erosion and stabilize if required. ■ Remove accumulated sediment when its volume reaches one-third the volume of the sediment storage. Properly dispose sediment and debris removed from the basin. ■ Check fencing for damage and repair.
SWPPP or WPCP
■ Sediment/Desilting basin must be discussed in Section 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP.
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 6 of 9
Source: CASQA
Figure 1
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 7 of 9
Source: CASQA
Figure 2
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 8 of 9
Source: CASQA
Figure 3
Sediment/Desilting Basin SC-2
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sediment/Desilting Basin SC-2 March 2024 9 of 9
Source: CASQA
Figure 4
SC-3
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Sediment Trap/Curb Cutback SC-3 March 2024 1 of 3
Temporary Sediment Trap/Curb Cutback
Standard Symbol
Definition and Purpose
A sediment trap/curb cutback is a temporary containment area that allows sediment in collected storm water to settle out during infiltration or before the runoff is discharged through a stabilized spillway. Sediment traps are formed by excavating or constructing an earthen embankment.
Curb cutback is implemented when the construction project uses the removed section of pavement and uses the depression of the curb as a temporary containment to collect sediment before reaching a storm drain.
Appropriate Applications
■ Sediment traps may be used on construction projects where the drainage area is less than 5 acres (ac). Traps should be placed where sediment-laden stormwater enters a storm drain or watercourse.
■ As a supplemental control, sediment traps provide additional protection for a water body or for reducing sediment before it enters a drainage system.
Limitations
■ Requires large surface areas to permit infiltration and sediment settling. ■ Size may be limited by availability of right-of-way.
■ Not appropriate for drainage areas larger than 5 ac.
■ Only removes large and medium-sized particles and requires upstream erosion control. ■ Sediment traps may appear attractive and dangerous to children, requiring protective fencing. ■ Sediment traps should not be located in live streams.
Temporary Sediment Trap/Curb
Cutback SC-3
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Sediment Trap/Curb Cutback SC-3 March 2024 2 of 3
■ Curb cutback typically does not allow for a large storage area and therefore requires frequent maintenance to prevent sediment-laden discharges.
Standards and Specifications
General Requirements
■ Areas under embankments, structural works, and sediment traps must be cleared and stripped of vegetation in accordance with Standard Specifications Section 17-2 – “Clearing and Grubbing.”
■ Earthwork must be in accordance with Standard Specifications Section 19 – “Earthwork.” Contractor is specifically directed to Standard Specifications Sections 19 5 and 19 6 entitled, “Compaction” and “Embankment Construction,” respectively. ■ Fencing, in accordance with Standard Specifications Section 80 – “Fences,” should be provided to prevent unauthorized entry.
■ Remove and dispose deposited solids from sediment traps under Standard Specifications Section 14-10 – “Solid Waste Disposal and Recycling” unless another method is authorized. ■ This BMP may be implemented on a project-by-project basis with other BMPs when determined necessary and feasible by the Resident Engineer (RE).
■ The outflow from sediment traps may be provided with outlet protection to prevent erosion and scouring of the embankment and channel. See BMP SS-10, “Outlet Protection/Velocity Dissipation Devices.”
■ For curb cutback, excavate soil from behind the curb, sidewalk, or roadway at least 3 to 4 inches down from the top of the hardscape and bring the soil back, at a minimum, 3 to 4 feet from the hardscape. Site conditions might allow for increase in capacity.
Other Considerations
■ The sediment trap should be situated according to the following criteria: (1) by excavating a suitable area or where a low embankment can be constructed across a swale, (2) where failure would not cause loss of life or property damage, and (3) to provide access for maintenance, including sediment removal and sediment stockpiling in a protected area. ■ Sediment traps should be sized to accommodate a settling zone and sediment storage zone with recommended minimum volumes of 67 cubic yards per acre (yd3/ac) and 33 yd3/ac of contributing drainage area, respectively, based on 0.5 inches of runoff volume over a 24-hour period. Multiple traps and/or additional volume may be required to accommodate site-specific rainfall and soil conditions.
■ Use rock or vegetation to protect the trap outlets against erosion. ■ Traps with an impounding levee greater than 4.5 feet tall measured from the lowest point to the impounding area to the highest point of the levee, and traps capable of impounding more than 35,000 cubic feet, must be designed by a Civil Engineer registered with the state of California.
The design must be submitted to the RE for approval at least 7 days prior to basin construction.
The design should include maintenance requirements to ensure continuous function of the trap outlet and bypass structures.
Temporary Sediment Trap/Curb
Cutback SC-3
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Sediment Trap/Curb Cutback SC-3 March 2024 3 of 3
Maintenance and Inspection
■ Inspect sediment traps/curbs before, during, and after rainfall events and weekly year-round.
During extended rainfall events, inspect sediment traps at least every 24 hours. ■ If captured runoff has not completely infiltrated within 96 hours, then the sediment trap must be dewatered.
■ Inspect trap banks for embankment seepage and structural soundness. ■ Inspect outlet structure and rock spillway for any damage or obstructions. Repair damage and remove obstructions as needed or as directed by the RE. ■ Inspect outlet area for erosion and stabilize if required, or as directed by the RE. ■ Remove accumulated sediment when the volume has reached one-third the original trap volume.
■ Inspect fencing for damage and repair as needed or as directed by the RE. ■ Temporary sediment trap/ Curb cutback locations must be shown in the WPCDs along with other BMPs.
SWPPP or WPCP
■ Temporary sediment trap/curb cutback must be discussed in Section 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP
SC-4
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Check Dams SC-4
March 2024 1 of 4
Temporary Check Dams
Standard Symbol
Definition and Purpose
Temporary check dams reduce scour and channel erosion by reducing flow velocity and encouraging sediment settlement. A check dam is a small device constructed of rock, gravel bags, compost socks, fiber rolls, or other proprietary product placed across a natural or man-made channel or drainage ditch.
Appropriate Applications
■ Temporary check dams may be installed:
− In small open channels that drain 10 acres (ac) or less. − In steep channels where storm water runoff velocities exceed 5 feet/second. − During the establishment of grass linings in drainage ditches or channels. − In temporary ditches where the short length of service does not warrant establishment of erosion-resistant linings.
■ This BMP may be implemented on a project-by-project basis with other BMPs when determined necessary and feasible by the Resident Engineer (RE).
Limitations
Not to be used in live streams.
■ Not appropriate in channels that drain areas larger than 10 ac. ■ Not to be placed in channels that are already grass lined unless erosion is expected, as installation may damage vegetation.
■ Requires extensive maintenance following high-velocity flows.
Temporary Check Dams SC-4
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Check Dams SC-4
March 2024 2 of 4
■ Promotes sediment trapping, which can be re-suspended during subsequent storms or removal of the check dam.
■ Not to be constructed from straw bales or silt fence.
Standards and Specifications
General Requirements
■ Remove obstructions, rocks, clods, and debris greater than 1 inch in diameter from the ground before installing temporary check dams.
■ If check dams are used in combination with rolled erosion control product (RECP) or blanket, install the RECP or blanket first.
■ Place a temporary check dam perpendicular to the centerline of the ditch or drainage line. ■ Install the check dam with enough spillway depth to prevent flanking of a concentrated flow around its ends.
■ Type 1 or Type 2 check dams are appropriate for unlined ditches. Type 2 check dams are appropriate if the ditch is concrete lined.
Fiber Roll (Type 1) Check Dam
Refer to SC-5, “Fiber Rolls.”
■ Secure the fiber rolls with rope and notched wood stakes. ■ Drive the stakes into the soil until the notch is even with the top of the fiber roll. ■ Lace rope between the stakes and over the fiber roll. Knot the rope at each stake. ■ Tighten by driving the stakes further into the soil and forcing the fiber roll against the surface of the ditch or drainage line.
Gravel-filled Bag (Type 2) Check Dam
Bag Material: Bags are a geosynthetic material, either polypropylene, polyethylene, or polyamide woven fabric with (1) a minimum unit weight of 4 ounces per square yard, (2) mullen burst strength exceeding 300 pounds per square in (psi) in conformance with the requirements in ASTM designation D3786, and (3) ultraviolet stability exceeding 70 percent, in conformance with the requirements in ASTM designation D4355.
Bag Size: Each gravel-filled bag shall be 24 to 32 inches long, 16 to 20 inches wide, and 3 inches thick. Alternative bag sizes must be submitted to the RE for approval prior to deployment.
Gravel: Fill material is between 3/8 and 3/4 inches in diameter and must be clean and free from clay balls, organic matter, and other deleterious materials. Gravel-filled bags should be secured when being opened so gravel does not escape. Gravel-filled bags weigh between 30 and 50 pounds. Fill material is subject to approval by the RE.
■ Place a Type 2 temporary check dam as a single layer of gravel-filled bags, placed end-to-end to eliminate gaps.
Temporary Check Dams SC-4
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Check Dams SC-4
March 2024 3 of 4
■ If you need to increase the dam height, add more layers of gravel-filled bags. Stack the bags in the upper row to overlap the joints in the lower row. Stabilize the rows by adding more rows of bags in the lower layers.
■ Tightly abut bags and stack gravel bags using a pyramid approach. Gravel bags should not be stacked any higher than 3 feet.
■ Upper rows of gravel bags should overlap joints in lower rows.
Other Considerations
■ Check dams should be placed at a distance and height to allow small pools to form behind them. Install the first check dam approximately 15 feet from the outfall device and at regular intervals based on slope gradient and soil type.
■ For multiple check dam installation, backwater from the downstream check dam should reach the toe of the upstream dam.
■ High flows (typically a 2-year storm or larger) should safely flow over the check dam without an increase in upstream flooding or damage to the check dam. ■ Where grass is used to line ditches, check dams should be removed when grass has matured sufficiently to protect the ditch or swale from erosion. ■ Check dam materials should consist of biodegradable materials whenever feasible. ■ Rock check dams might be more applicable if concentrated flows are possible.
Maintenance and Inspection
■ Check dams must be inspected at a minimum weekly, prior to forecasted rain events, daily during extended rain events, and after the conclusion of rain events. ■ Replace missing rock, bags, fiber rolls, etc., that have degraded or become damaged. ■ Remove sediment when depth reaches one-third of the check dam height. ■ Remove accumulated sediment prior to permanent seeding or soil stabilization. ■ Remove check dam and accumulated sediment when check dams are no longer needed or when directed by the RE.
■ Removed sediment can be incorporated in the project at locations designated by the RE or disposed outside the highway right of way in conformance with the Standard Specifications.
SWPPP or WPCP
■ Temporary check dams must be discussed in Sections 600.1.1 and 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP.
Temporary Check Dams SC-4
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Check Dams SC-4
March 2024 4 of 4
SC-5
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Fiber Rolls SC-5 March 2024 1 of 6
Temporary Fiber Rolls
Standard Symbol
Definition and Purpose
A temporary fiber roll consists of wood excelsior, rice or wheat straw, or coconut fibers that are rolled or bound into a tight tubular roll and placed on the toe and face of slopes to intercept runoff, reduce its flow velocity, release the runoff as sheet flow, and remove sediment. Temporary fiber rolls may also be used for drainage inlet protection and as check dams under certain situations.
Appropriate Applications
■ This BMP may be implemented on a project-by-project basis with other BMPs when determined necessary and feasible by the Resident Engineer (RE).
■ Fiber rolls may be applied as both temporary and permanent sediment controls (after receiving approval from Division of Maintenance).
■ Fiber rolls may be used as check dams in unlined ditches or as temporary drainage inlet protection down-slope of exposed soil areas.
■ Along the toe, top, face, and at grade breaks of exposed and erodible slopes to shorten slope length and spread runoff as sheet flow.
■ Below the toe of exposed and erodible slopes.
■ Around temporary stockpiles.
■ Along the perimeter of a project.
Limitations
■ Runoff and erosion may occur if fiber roll is not adequately trenched in. ■ Fiber rolls at the toe of slopes greater than 5:1 (H:V) may require the use of a large sediment barrier as specified in Standard Specifications Section 13 – 10.03D Temporary Large Sediment Temporary Fiber Rolls SC-5
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Fiber Rolls SC-5 March 2024 2 of 6
Barrier or installations achieving the same protection (i.e., stacked smaller-diameter fiber rolls, etc.).
■ Difficult to move once saturated.
■ Fiber rolls could be transported by high flows if not properly staked and/or trenched in. ■ Fiber rolls have limited sediment capture zone.
■ Do not use fiber rolls on slopes subject to creep, slumping, or landslide. ■ Plastic netting should not be used.
■ Plastic netting is only allowed where fiber rolls will be used for short durations and will be removed (requires RE approval).
Standards and Specifications
Materials
■ Fiber rolls must be pre-manufactured and filled with weed-free rice or wheat straw, wood excelsior, or coconut fiber. Fiber rolls must be covered with biodegradable jute, sisal, or coir fiber netting secured tightly at each end.
■ Fiber rolls must have a minimum functional longevity of 1 year. ■ Fiber rolls must be:
− 8 to 10 inches in diameter and at least 1.1 pounds per foot (lb/ft) − 10 to 12 inches in diameter and at least 3 lb/ft
■ Large sediment barriers are a subset of fiber rolls. Large sediment barriers must be:
− 18 to 22 inches in diameter
− At least 8 feet in length
− At least 6.5 lb/ft
■ Fiber rolls used within the jurisdiction of the Lahontan Regional Water Quality Control Board must be made entirely of biodegradable materials if the project is near an environmentally sensitive area, are intended to be left in place after construction is completed, or regulatory permits prohibit the use of non-photo/biodegradable fiber rolls. ■ Submit a Certificate of Compliance for fiber rolls.
■ Rope to fasten fiber rolls must be 1/4 inches in diameter and biodegradable, such as sisal or manila.
■ Wood stakes must be untreated fir, redwood, cedar, or pine and cut from sound timber. The ends must be pointed for driving into the ground. Notched stakes must be at least 1 by 2 by 24 inches in size. Stakes without notches must be at least 1 by 1 by 24 inches.
Temporary Fiber Rolls SC-5
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Fiber Rolls SC-5 March 2024 3 of 6
Typical Temporary Fiber Roll Installation
■ Before installing fiber roll, remove obstructions from the ground, including rocks, clods, and debris greater than 1 inch in diameter.
■ For any 20-foot section of fiber roll, prevent the fiber roll from varying more than 5 percent from level.
■ Use the following spacing unless otherwise noted on the project plans or special provisions:
− 10 feet apart for slopes steeper than 2:1 (H:V)
− 15 feet apart for slopes from 2:1 to 4:1 (H:V)
− 20 feet apart for slopes from 4:1 to 10:1 (H:V)
− 50 feet apart for slopes flatter than 10:1 (H:V)
■ For Type 1 installations:
− Place in a furrow that is from 2 to 4 inches deep.
− Fasten with wood stakes every 4 feet along the length of the fiber roll. − Fasten the ends of the fiber roll by placing a stake 6 inches from the end of the roll. − Drive the stakes into the soil so the top of the stake is less than 2 inches above the top of the fiber roll.
■ For Type 2 installations:
− Fasten with notched wood stakes and rope.
− Drive stakes into the soil until the notch is even with the top of the fiber roll. − Lace the rope between stakes and over the fiber roll. Knot the rope at each stake. − Tighten the fiber roll to the surface of the slope by driving the stakes further into the soil. ■ If more than one fiber roll is placed in a row, the rolls should overlap, not abut. Stagger overlapping joints in adjacent rows by 5 to 10 feet.
Typical Large Sediment Barrier Installation
■ Place a single row of fiber rolls end-to-end approximately parallel with the slope contour. For any 20-foot section of fiber roll, do not allow the fiber roll to vary by more than 5 percent from level.
■ Place the fiber rolls in a furrow that is from 6 to 8 inches deep. ■ Secure the fiber rolls with wood stakes 4 feet apart. ■ Place a stake 18 inches from each end of each fiber roll. ■ Drive the stakes into the soil such that the top of the stakes are less than 2 inches above the top of the fiber rolls.
■ Angle the last 6 feet upslope at the downhill end of the run.
Temporary Fiber Rolls SC-5
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Fiber Rolls SC-5 March 2024 4 of 6
Removal
■ For permanent installations, do not remove fiber rolls. Fiber rolls will degrade over time, while underlying soils are stabilized by other BMPs.
■ For temporary installations, remove fiber rolls, collect and dispose sediment accumulation, and fill and compact holes, trenches, depressions or any other ground disturbance to blend with adjacent ground.
Maintenance and Inspection
■ Remove sediment from behind the fiber roll if sediment is 1/3 of fiber roll height above ground. ■ Repair or adjust the fiber roll if rills or other evidence of concentrated runoff occur beneath the fiber roll.
■ Repair or replace the fiber roll if they become split, torn, or unraveled. ■ Add stakes if the fiber roll slumps or sags.
■ Replace broken or split wood stakes.
■ Remove sediment deposits, trash, and debris from fiber roll as needed. If removed sediment is deposited within project limits, it must be stabilized and not exposed to erosion by wind or water. ■ Perform maintenance as needed or as required by the RE or by Construction General Permit or the Lake Tahoe Hydrologic Unit Construction General Permit requirements. ■ Inspect fiber rolls before and following rainfall events and a least daily during prolonged rainfall.
Perform maintenance as needed or as required by the RE. ■ Maintain fiber rolls to provide an adequate sediment holding capacity and runoff velocity reduction.
■ Fiber roll placement must be shown on the WPCDs.
SWPPP or WPCP
■ Fiber rolls must be discussed in Sections 600.1.1 and 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP and the respective WPCDs.
Temporary Fiber Rolls SC-5
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Fiber Rolls SC-5 March 2024 5 of 6
Temporary Fiber Rolls SC-5
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Fiber Rolls SC-5 March 2024 6 of 6
SC-6
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Gravel Bag/Earthen Berm SC-6 March 2024 1 of 3
Temporary Gravel Bag/Earthen Berm
Standard Symbol
Definition and Purpose
A temporary gravel bag berm consists of a single row of gravel bags that are installed end to end to form a barrier across a slope to intercept runoff, reduce its flow velocity, release the runoff as sheet flow, and provide some sediment removal. Gravel bags can be used where flows are moderately concentrated, such as ditches, swales, and storm drain inlets (see SC-10, “Drainage Inlet Protection”) to divert and/or detain flows.
Temporary earthen berms are linear sediment barriers designed to intercept sheet flows. Water gets impounded upstream of the earthen berm, which allows sediment to settle out and release runoff as sheet flow, preventing erosion.
Appropriate Applications
BMP may be implemented on a project-by-project basis with other BMPs when determined necessary and feasible by the Resident Engineer (RE).
■ Along streams and channels.
■ Below the toe of exposed and erodible slopes.
■ Down slope of exposed soil areas.
■ Around stockpiles.
■ Across channels to serve as a barrier for utility trenches or provide a temporary channel crossing for construction equipment to reduce stream impacts. ■ Parallel to a roadway to keep sediment off paved areas. ■ At the top of slopes to divert roadway runoff away from disturbed slopes. ■ Along the perimeter of a site.
Temporary Gravel Bag/Earthen Berm SC-6
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Gravel Bag/Earthen Berm SC-6 March 2024 2 of 3
■ To divert or direct flow or create a temporary sediment basin. ■ During construction activities in stream beds when the contributing drainage area is less than 5 acres.
■ When extended construction period limits the use of either silt fences or straw bale barriers. ■ When site conditions or construction sequencing require adjustments or relocation of the barrier to meet changing field conditions and needs during construction. ■ At grade breaks of exposed and erodible slopes to shorten slope length and spread runoff as sheet flow.
Limitations
■ Degraded gravel bags may rupture when removed, spilling contents. ■ Installation can be labor intensive.
■ Limited durability for long-term projects.
■ When used to detain concentrated flows, maintenance requirements increase. ■ Earthen berms should not be used to intercept flows with moderate to high velocities that may erode the earthen berm.
■ Earthen berms are susceptible to erosion from concentrated flows.
Standards and Specifications
Materials
■ Bag Material: The gravel bag material must comply with Section 96-1.02F Gravel-Filled Bag of the Standard Specifications.
■ Bag Size: Each gravel-filled bag should be 24 to 32 inches long, 16 to 20 inches wide, and 3 inches thick. Alternative bag sizes must be submitted to the RE for approval prior to deployment.
■ Gravel: Fill material should be between 3/8 and 3/4 inches in diameter and be clean and free from clay balls, organic matter, and other deleterious materials. The opening of gravel-filled bags must be secured such that gravel does not escape. Gravel-filled bags weigh between 30 and 50 pounds. Fill material is subject to approval by the RE. ■ Earthen berms must comply with Standard Specifications Section 13-10.03I Installation
■ When used as a linear control for sediment removal:
− Install along a level contour.
− Place gravel-filled bags end to end to eliminate gaps in a gravel-bag berm. − Angle the last 6 feet upslope at the downhill end of the run. − Stack the bags such that the upper row overlaps the joints in the lower row.
Temporary Gravel Bag/Earthen Berm SC-6
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Gravel Bag/Earthen Berm SC-6 March 2024 3 of 3
− Add layers of gravel-filled bags to increase the height of a temporary gravel-bag berm if needed. Stack the bags in the upper row to overlap the joints in the lower row. Stabilize the rows by adding rows of bags in the lower layers.
■ Generally, gravel-bag barriers can be used in conjunction with temporary soil stabilization controls up slope.
■ Construct gravel-bag barriers with a setback from the toe of a slope. Where it is determined to be not practicable due to specific site conditions, the gravel-bag barrier may be constructed at the toe of the slope but be constructed as far from the slope toe as practicable. ■ Refer to SC-4, “Temporary Check Dams” when used for concentrated flows. ■ Submit a Certificate of Compliance for gravel-filled bag material. ■ Earthen berms are constructed with either native soil or an alternative selected material. ■ Earthen berms must be at least 8 inches high and 36 inches wide. ■ Earthen berms must be compacted, either manually or mechanically.
Maintenance and Inspection
■ Gravel-bag/earthen berms must be inspected in accordance with CGP requirements for the associated project type and risk level, or with the LTCGP. At a minimum, BMPs must be inspected weekly, prior to forecasted rain events, daily during extended rain events, and after the conclusion of rain events.
■ Reshape or replace gravel bags as needed, or as directed by the RE. ■ Repair washouts or other damages as needed, or as directed by the RE. ■ Inspect gravel-bag/earthen berms for sediment accumulations and remove sediment when accumulation reaches one-third of the berm height. Removed sediment can be incorporated in the project at locations designated by the RE or disposed outside the highway right of way in conformance with the Standard Specifications.
■ Remove gravel-bag berms when no longer needed. Remove sediment accumulations and clean, re-grade, and stabilize the area.
■ If using earthen berm, ensure soil remains compacted through the duration of the berm. ■ Maintain earthen berms to provide sediment-holding capacity and to reduce concentrated flow velocities.
■ Repair the berm if rills or other evidence of concentrated runoff has overtopped it. ■ Gravel bag/Earthen berm placement must be shown on the WPCDs and reflect site conditions.
SWPPP or WPCP
■ Gravel bag/Earthen berm must be discussed in Sections 600.1.1 and 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP and shown in the respective WPCDs.
SC-7
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Street Sweeping SC-7
March 2024 1 of 2
Street Sweeping
Standard Symbol
SS
Definition and Purpose
BMPs to remove tracked sediment to prevent the sediment from entering a storm drain or receiving waters.
Appropriate Applications
These practices are implemented anywhere sediment is tracked from the project site onto public or private paved roads, typically at jobsite entrances and exits.
Limitations
Sweeping and vacuuming may not be effective when soil is wet or muddy.
Standards and Specifications
General Requirements
■ Sweep by hand or mechanical methods, such as vacuuming. Kick brooms or sweeper attachments may not be used.
■ At least one street sweeper in good working order must be at the job site at all times when street sweeping work is required.
■ Use one of the following types of street sweepers:
− Mechanical sweeper followed by a vacuum-assisted sweeper − Vacuum-assisted, dry, waterless, sweeper
− Regenerative-air sweeper
Street Sweeping SC-7
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Street Sweeping SC-7
March 2024 2 of 2
■ Submit the number and type of street sweepers that will be used on the project for each activity at least 5 business days before starting the activities listed above. Keep and submit street sweeping activity records that include sweeping times, locations, and the quantity of material collected.
■ Sweep paved roads at construction entrance and exit locations and on-site paved areas:
− During clearing and grubbing, earthwork, trenching, and pavement-structure construction activities.
− When vehicles are entering and leaving the job site.
− After soil-disturbing activities.
− After observing off-site tracking of material.
■ Sweep within 1 hour if sediment or debris is observed during the activities described above that require sweeping.
■ Sweep within 24 hours if sediment or debris is observed during activities that do not require sweeping.
■ Keep dust to a minimum during street sweeping activities. Use water for dust control or a vacuum whenever dust generation is excessive or sediment pickup is ineffective. Refer to WE-1 for wind erosion control BMPs.
■ Remove collected material, including sediment, from paved shoulders, drainage inlets, curbs and dikes, and other drainage areas.
■ After sweeping is finished, collected material may be stockpiled. Stockpiles protection is included in WM-03 Stockpile Management. If not mixed with debris, trash, or potentially hazardous objects, consider incorporating the removed sediment back into the project if approved by the Resident Engineer. Otherwise, dispose stockpiled material at least once per week according to Standard Specifications Section 14-10. ■ Street sweeping does not void the requirements for residue collection included in other work activities, such as grooving, grinding, or asphalt concrete planning.
Maintenance and Inspection
■ Inspect potential sediment tracking locations daily.
■ Monitor and inspect tracking control BMPs such as TC-1, “Temporary Construction Entrance” to reduce sediment accumulation on roads.
■ Be careful not to sweep up any unknown substance or any object that may be hazardous. ■ Adjust brooms frequently; maximize efficiency of sweeping operations. ■ Sweeper material must be disposed in compliance with waste regulations.
SWPPP or WPCP
■ Street sweeping must be discussed in Section 600.1.3 of the SWPPP or Sections 30.2.2 and
30.2.3 of the WPCP.
SC-8
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sandbag Barrier SC-8
March 2024 1 of 3
Sandbag Barrier
Definition and Purpose
A sandbag barrier is a temporary linear sediment barrier that consists of stacked sandbags designed to intercept and slow the flow of sediment-laden sheet flow runoff. Sandbag barriers allow sediment to settle from runoff before water leaves the construction site.
Appropriate Applications
■ Along the perimeter of a site.
■ Along streams and channels.
■ Below the toe of exposed and erodible slopes.
■ Down slope of exposed soil areas.
■ Around stockpiles.
■ Across channels to serve as a barrier for utility trenches or provide a temporary channel crossing for construction equipment, and to reduce stream impacts in accordance with the approved Temporary Creek Diversion Plan.
■ Parallel to a roadway to keep sediment off paved areas. ■ At the top of slopes to divert roadway runoff away from disturbed slopes. ■ To divert or direct flow or create a temporary sediment/desilting basin. ■ During construction activities, in stream beds when the contributing drainage area is less than 5 acres.
■ When extended construction period limits the use of either silt fences or straw bale barriers. ■ Along the perimeter of vehicle and equipment fueling and maintenance areas or chemical storage areas.
Sandbag Barrier SC-8
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sandbag Barrier SC-8
March 2024 2 of 3
■ To capture and detain non-stormwater flows until proper cleaning operations occur. ■ When site conditions or construction sequencing require adjustments or relocation of the barrier to meet changing field conditions and needs during construction. ■ To temporarily close or continue broken, damaged, or incomplete curbs.
Standards and Specification
Materials
■ Sandbag Material: Sandbags can be woven polypropylene, polyethylene, or polyamide fabric with (1) a minimum unit weight of 4 ounces per square yard, (2) mullen burst strength exceeding 300 pounds per square inch in conformance with the requirements in ASTM designation D3786, and (3) ultraviolet stability exceeding 70 percent in conformance with the requirements in ASTM designation D4355. Use of burlap is not acceptable.
■ Sandbag Size: Each sand-filled bag should be 18 inches long, 12 inches wide, and 3 inches thick, and have a mass of approximately 33 pounds. Bag dimensions are nominal and may vary based on locally available materials. Alternative bag sizes must be submitted to the RE for approval prior to deployment.
■ Fill Material: All sandbag fill material can be non-cohesive, Class 1 or Class 2 permeable material free from clay and deleterious material, conforming to the provisions in Standard Specifications Section 47-2.02D – “Permeable Material.” The requirements for the Durability Index and Sand Equivalent do not apply. Fill material is subject to approval by the Resident Engineer (RE).
Installation
■ When used as a linear sediment control:
− Install along a level contour.
− Turn ends of sandbag row upslope to prevent flow around the ends. − Generally, sandbag barriers may be used in conjunction with temporary soil stabilization controls upslope to provide effective erosion and sediment control. ■ Construct sandbag barriers with a setback of at least 3 feet from the toe of a slope. Where it is determined to be not practical due to specific site conditions, the sandbag barrier may be constructed at the toe of the slope, but should be constructed as far from the slope toe as practicable.
Limitations
■ Limit the drainage area upstream of the barrier to 5 acres. ■ Degraded sandbags may rupture when removed, spilling sand. ■ Installation can be labor intensive.
■ Limited durability for long-term projects.
■ When used to detain concentrated flows, maintenance requirements increase.
Sandbag Barrier SC-8
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Sandbag Barrier SC-8
March 2024 3 of 3
■ Consider using gravel bags whenever possible since they often do not require as much maintenance or impact wildlife when used near environmentally sensitive areas.
Maintenance and Inspection
■ Inspect sandbag barriers before and after each rainfall event, and weekly year-round. ■ Reshape or replace sandbags as needed, or as directed by the RE. ■ Repair washouts or other damages as needed, or as directed by the RE. ■ Inspect sandbag barriers for sediment accumulations and remove sediments when accumulation reaches one-third the barrier height. Removed sediment can be incorporated in the project at locations designated by the RE or disposed outside the highway right of way in conformance with the Standard Specifications 14-10.
■ Remove sandbags when no longer needed. Remove sediment accumulation and clean, re-grade, and stabilized the area. No sandbags should be left in place after construction activities are complete.
SWPPP or WPCP
■ Sandbag barriers must be discussed in Sections 600.1.1 and 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP.
SC-9
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Straw Bale Barrier SC-9 March 2024 1 of 4
Temporary Straw Bale Barrier
Standard Symbol
Definition and Purpose
A temporary straw bale barrier is a temporary linear sediment barrier consisting of straw bales designed to intercept and slow sediment-laden sheet flow runoff. Temporary straw bale barriers allow sediment to settle from runoff before water leaves the construction site.
Appropriate Applications
■ Along the perimeter of a site.
■ Along streams and channels.
■ Below the toe of exposed and erodible slopes.
■ Downslope of exposed soil areas.
■ Around stockpiles.
■ Across minor swales or ditches with small catchments. ■ Around above-grade-type temporary concrete washouts (see WM-8, “Concrete Waste Management”).
■ Parallel to a roadway to keep sediment off paved areas.
Limitations
■ Installation can be labor intensive.
■ Temporary straw bale barriers are maintenance intensive. ■ Degraded straw bales may fall apart when removed or if left in place for extended periods. ■ Cannot be used on paved surfaces.
Temporary Straw Bale Barrier SC-9
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Straw Bale Barrier SC-9 March 2024 2 of 4
■ Not to be used for drain inlet protection.
■ Not to be used in areas of concentrated flow.
■ Can be an attractive food source for some animals.
■ May introduce undesirable non-native plants to the area.
Standards and Specifications
Materials
■ Straw must conform to the provisions in Standard Specifications Section 21-2.02H – “Straw.” ■ Each straw bale should be a minimum of 14 inches wide, 18 inches high, 36 inches long, and have a minimum weight of 50 pounds (lb).
■ The straw bale must be composed entirely of vegetative matter, except for the binding material. ■ Bales can be bound by either wire, nylon, or polypropylene string placed horizontally. Jute and cotton binding may not be used. Baling wire should be at least 16 gauge. Nylon or polypropylene string should have a diameter of approximately 0.08 inches with a breaking strength of 80 lb.
■ Wood or metal posts should be used as stakes. Posts for straw bale barriers must comply with Standard Specifications Section 16-2.03 – “Temporary High-visibility Fences.” Installation
■ Place a single row of straw bales end to end and parallel with the slope contour. Do not allow any 20-foot section of straw bale barrier to vary by more than 5 percent from level. ■ Place straw bales in a trench or key them into the slope. Place the bales such that the binding wire or string does not come in contact with the soil. Use wood or metal posts as stakes. ■ Secure each straw bale with two posts. The first post in each bale must be driven toward the previously laid bale to force the bales together. Drive the posts into the soil such that the top of the post is less than 2 inches above the top of the straw bale. The post must extend a minimum of 2 feet in the ground below the bottom of the straw bales. ■ Angle the last 6 feet upslope at the downhill end of the run. ■ See page 4 of this Fact Sheet for installation detail.
Other Considerations
■ Construct straw bale barriers with a setback of at least 3 feet from the toe of a slope. Where it is determined to be not practical due to specific site conditions, the straw bale barrier may be constructed at the toe of the slope but be constructed as far from slope the toe as practical. ■ This BMP may be implemented on a project-by-project basis in addition to other BMPs when determined necessary and feasible by the Resident Engineer (RE). ■ Straw bale barriers may be used in combination with a silt fence (see SC-2 – “Temporary Silt Fence”) for additional sediment control.
Temporary Straw Bale Barrier SC-9
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Straw Bale Barrier SC-9 March 2024 3 of 4
Maintenance and Inspection
■ At a minimum, BMPs must be inspected weekly, prior to forecasted rain events, daily during extended rain events, and after the conclusion of rain events. ■ Inspect straw bale barriers for sediment accumulations and remove sediment when depth reaches one-third the barrier height. Removed sediment should be disposed outside the highway right-of-way in conformance with the Standard Specifications. ■ Replace or repair damaged bales as needed or as directed by the RE. ■ Repair washouts or other damages as needed or as directed by the RE. ■ Remove straw bales when no longer needed. Remove sediment accumulation, and clean, re-grade, and stabilized the area.
SWPPP or WPCP
Straw bale barriers must be discussed in Section 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP. Straw bale barrier placement must be shown on the WPCDs and reflect current site conditions.
Temporary Straw Bale Barrier SC-9
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Straw Bale Barrier SC-9 March 2024 4 of 4
SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 1 of 9
Temporary Drainage Inlet Protection
Standard Symbol
Definition and Purpose
Temporary drainage inlet protection consists of devices used at storm drain inlets that detain and/or filter sediment-laden runoff prior to discharge into storm drainage systems. This is achieved by allowing sediment to settle, and/or filtering sediment upstream of a linear sediment barrier.
Appropriate Applications
■ Where ponding will not encroach into highway traffic. ■ Where sediment-laden surface runoff may enter an inlet. ■ Where disturbed drainage areas have not yet been permanently stabilized. ■ Where the drainage area is 1 acre or less.
■ Can be used year-round.
Limitations
■ Requires an adequate area for water to pond without encroaching upon traveled way; it should not present an obstacle to oncoming traffic.
■ May require other methods of temporary protection to prevent sediment-laden stormwater and non-stormwater discharges from entering the storm drain system. ■ Sediment removal may be difficult in high-flow conditions or if runoff is heavily sediment laden. If high-flow conditions are expected, use other on-site sediment trapping techniques, such as SC-4 – “Temporary Check Dams,” in conjunction with temporary drainage inlet protection. ■ Frequent maintenance is required.
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 2 of 9
■ Silt fence inlet protection is appropriate in open areas that are subject to sheet flow and for flows not exceeding 0.5 cubic feet per second (cfs).
■ Gravel bag barriers for inlet protection are applicable when sheet flows or concentrated flows exceed 0.5 cfs and it is necessary to allow overtopping to prevent flooding. ■ Fiber rolls and foam barriers are not appropriate for locations where they cannot be properly anchored to the surface.
■ Excavated drop inlet sediment traps are appropriate where relatively heavy flows are expected and overflow capability is needed.
■ For drainage areas larger than 1 acre, runoff should be routed to a sediment trapping device designed for larger flows. See BMPs SC-2, “Sediment/Desilting Basin” and SC-3, “Sediment Trap/Curb Cutback.”
Standards and Specifications
General Requirements
■ Refer to Standard Specifications Section 13-6.03C for “Temporary Drainage Inlet Protection” and 13-6.03F for “Rigid Plastic Barriers.”
■ Identify existing and/or planned storm drain inlets that have the potential to receive sedimentladen surface runoff. Determine if storm drain inlet protection is needed, and which method or combination of methods to use. Update inlet protection as site conditions change. ■ Use a linear sediment barrier to redirect runoff and control ponding to prevent ponding from encroaching on the traveled way or overtopping the curb or dike. ■ Prior to installation, clear the area around each inlet of obstructions, including rocks, clods, and debris greater than 1 inch in diameter.
■ Install linear sediment barriers upstream of the inlet and parallel with the curb, dike, or flow line to keep sediment from entering the inlet.
■ Remove accumulated sediment according to maintenance and inspection recommendations.
Accumulated sediment may be disposed outside the highway right-of-way in conformance with Standard Specifications Section 14-10.
Type 1 – Silt Fence
■ This method should be used for drain inlets that require protection in areas where finished grade is established and erosion control seeding has been applied or is pending. The silt fence (Type 1) protection is illustrated on page 6. Do not place filter fabric underneath the inlet grate since the collected sediment may fall into the drain inlet when the fabric is removed or replaced.
Type 2 – Excavated Drop Inlet Sediment Trap
■ This method may be used for drainage inlets that require protection in areas that have been cleared and grubbed, and where exposed soil areas are subject to grading. The excavated drop inlet sediment trap (Type 2) is illustrated on page 7. Construction is similar to a temporary silt fence; see BMP SC-1, “Temporary Silt Fence.” Size the excavated trap to provide a minimum storage capacity calculated at the rate of 67 cubic yards per acre of drainage area.
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 3 of 9
Type 3A – Gravel Bag Berm for Combined Inlets
■ This method may be used for drain inlets surrounded by asphalt concrete (AC) or paved surfaces. The gravel-bag berm for combined inlets (Type 3A) is illustrated on pages 8-9. Flow from a severe storm must not overtop the curb. In areas of high clay and silts, use filter fabric and gravel as additional filter media. Construct gravel bags in accordance with BMP SC-6, “Temporary Gravel Bag/Earthen Berm.” Gravel bags are used due to their high permeability.
Type 3B – Gravel Bag Berm for Grate Inlets
■ This method may be used for drainage inlets surrounded by AC or paved surfaces. The gravel bag berm for grate inlets (Type 3B) is illustrated on page 10. In areas of high clay and silts, use filter fabric and gravel as additional filter media. Place gravel bags in accordance with BMP SC6, “Temporary Gravel Temporary Bag/Earthen Berm.” Gravel bags are used due to their high permeability.
Type 4A – Flexible Sediment Barrier for Grate Inlets
■ This method may be used for drainage inlets that require protection in areas that have been cleared and grubbed, and where exposed soil areas are subject to grading. Flexible sediment barrier for grate inlets (Type 4A) is placed around the inlet and keyed and anchored to the surface. They are intended for use as inlet protection where the area around the inlet is unpaved and the foam barrier or fiber roll can be secured to the surface. Place fiber rolls over the erosion control blanket. Resident Engineer (RE) or appropriate licensed professional approval is required.
Type 4B – Flexible Sediment Barrier for Combined Inlets ■ This method may be used for drainage inlets that require protection in areas that have been cleared and grubbed, and where exposed soil areas are subject to grading. Flexible sediment barrier for combined inlets (Type 4B) is placed in rows upstream of the inlet and along the curb or dike. The barriers are keyed and anchored to the surface. They are intended for use as inlet protection where the area around the inlet is unpaved and the foam barrier or fiber roll can be secured to the surface. Place the barrier to provide a tight joint with the curb or dike. Cut the cover fabric or jacket to ensure a tight fit. RE approval is required.
Type 5 – Sediment Filter Bag
■ This method may be used in areas with vehicle and equipment traffic that could damage aboveground inlet protection devices. To install the sediment filter bags, (1) remove the drainage inlet grate, (2) place the sediment filter bag in the opening, and (3) replace the grate to secure the sediment filter bag in place.
Type 6A – Catch Basin with Grate
■ Catch basin with grate (Type 6A) is shown on page 16. Cover grate inlet with rigid plastic barrier and secure on each end with gravel-filled bags. If using a rigid sediment barrier and the grated inlet does not have a curb opening, placed the barrier using a gasket to prevent runoff from flowing under the barrier. Secure the barrier to the pavement with nails and adhesive, gavelfilled bags, or a combination of both.
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 4 of 9
Type 6B – Curb Inlet without Grate
■ Curb Inlet without Grate (Type 6B). Place the flexible sediment barrier across the curb inlet opening and secure with gravel-filled bags.
Maintenance and Inspection
General Requirements
■ Inspect all drainage inlet protection devices before and after every rainfall event and weekly year-round. During extended rainfall events, inspect inlet protection devices at least once every 24 hours.
■ Inspect the storm drain inlet after severe storms to check for bypassed material. ■ Remove all drainage inlet protection devices within 30 days after the site is stabilized or when the inlet protection is no longer needed.
− Bring the disturbed area to final grade and smooth and compact it. Appropriately stabilize all bare areas around the inlet.
− Clean and re-grade area around the inlet and clean the inside of the storm drain inlet, as it must be free of sediment and debris at the time of final inspection.
Type 1 – Filter Fabric Fence
■ Make sure the stakes are securely driven in the ground and are structurally sound (i.e., not bent, cracked, or splintered and are reasonably perpendicular to the ground). Replace damaged stakes.
■ Replace or clean the fabric when it becomes clogged with sediment. Make sure the fabric does not have any holes or tears. Repair or replace fabric as needed or as directed by the RE. ■ At a minimum, remove the sediment behind the fabric fence when accumulation reaches onethird the height of the fence or barrier height.
Type 2 – Excavated Drop Inlet Sediment Trap
■ Remove sediment from basin when its volume has been reduced by one-half.
Type 3A – Gravel-bag Berm for Combined Inlets
■ Inspect bags for holes, gashes, and snags.
■ Check gravel bags for proper arrangement and displacement. Remove the sediment behind the barrier when it reaches one-third the height of the barrier.
Type 3B – Gravel-bag Berm for Grate Inlets
■ Inspect bags for holes, gashes, and snags.
■ Check gravel bags for proper arrangement and displacement. Remove the sediment behind the barrier when it reaches one-third the height of the barrier.
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 5 of 9
Type 4A – Flexible Sediment Barrier for Grate Inlets
■ Check flexible sediment barrier for proper arrangement and displacement. Remove the sediment behind the barrier when it reaches one-third the height of the barrier.
Type 4B – Flexible Sediment Barrier for Combined Inlets ■ Check flexible sediment barrier for proper arrangement and displacement. Remove the sediment behind the barrier when it reaches one-third the height of the barrier.
Type 5 – Sediment Filter Bag
■ Change sediment filter bag carefully, ensuring captured sediment does not spill into the drainage inlet.
Type 6A – Catch Basin with Grate
■ Check barrier and gravel-filled bags for proper arrangement and displacement. Routinely remove accumulated sediment.
Type 6B – Curb Inlet without Grate
■ Check barrier and gravel-filled bags for proper arrangement and displacement. ■ Remove the sediment behind the barrier when it reaches one-third the height of the barrier.
SWPPP or WPCP
■ Temporary drainage inlet protection must be discussed in Section 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP. Temporary drainage inlet protection placement type must be shown on the WPCDs and reflect site conditions.
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 6 of 9
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 7 of 9
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 8 of 9
Temporary Drainage Inlet Protection SC-10
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Drainage Inlet Protection SC-10 March 2024 9 of 9
SC-11
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Compost Stocks SC-11 March 2024 1 of 5
Temporary Compost Stocks
//////CS///////
Standard Symbol
Definition and Purpose
Temporary compost socks are a mesh sock that contains compost that acts as three-dimensional, biodegradable structures that intercept and filter sheet flow. Compost socks can filter runoff, retain sediment, and reduce sheet flow velocities. Compost socks may be used as either a temporary or permanent sediment control measure.
Appropriate Applications
■ As both temporary and permanent sediment controls.
■ Along the toe, top, face, and at grade breaks of exposed and erodible slopes to shorten slope length and spread runoff as sheet flow.
■ Along the perimeter of a project.
■ As check dams in unlined ditches.
■ Downslope of exposed soil areas.
■ At operational storm drains as a form of inlet protection. ■ Around temporary stockpiles.
Limitations
■ Compost can potentially leach nutrients into runoff and negatively affect water quality.
Compost should not be used directly upstream from a nutrient-impaired water body. ■ Compost socks are susceptible to damage by traffic. Compost socks may be used around heavy machinery, but frequent disturbance decreases sock performance.
Temporary Compost Stocks SC-11
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Compost Stocks SC-11 March 2024 2 of 5
Standards and Specifications
General Requirements
■ Compost socks must comply with Standard Specifications 13-10.03J, 21-2.02Q and 21-
2.03Q.
■ Compost for compost socks must comply with Standard Specifications Section 21-
2.01D(2) and 21-2.02K.
■ Compost sock installation is illustrated in Standard Plan H51. ■ Compost socks consist of a 12-inch-diameter mesh tube filled with compost. The mesh tube must be composed of a natural biodegradable product, such as cotton, jute, sisal, burlap, or coir. The mesh tube must be clean, evenly woven, and free of encrusted concrete or other contaminating materials, cuts, tears, broken or missing yarns, and thin, open, or weak places.
■ Compost socks must have a functional longevity of 1 year.
Installation
■ Before installing a compost sock, remove obstructions from the ground, including rocks, clods, and debris greater than 1 inch in diameter.
■ For any 20-foot section of compost sock, prevent the compost sock from varying more than 5 percent from level.
■ Use the following spacing unless otherwise noted on the project plans or special provisions:
− 10 feet apart for slopes steeper than 2:1 (H:V)
− 15 feet apart for slopes from 2:1 to 4:1 (H:V)
− 20 feet apart for slopes from 4:1 to 10:1 (H:V)
− 50 feet apart for slopes flatter than 10:1 (H:V)
■ Place mesh tube, secure the end, and fill uniformly with compost. Secure the remaining end.
■ For Type 1 installations:
− Place in a furrow that is from 2 to 4 inches deep.
− Fasten with wood stakes every 4 feet along the length of the compost sock. − Fasten the ends of the compost sock by placing a stake 6 inches from its end. − Drive the stakes into the soil so the stake top is less than 2 inches above the top of the compost sock.
■ For Type 2 installations:
− Fasten with notched wood stakes and rope.
Temporary Compost Stocks SC-11
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Compost Stocks SC-11 March 2024 3 of 5
− Drive stakes into the soil until the notch is even with the top of the compost sock. − Lace the rope between stakes and over the compost sock. Knot the rope at each stake.
− Tighten the fiber roll to the surface of the slope by driving the stakes further into the soil.
■ If more than one compost sock is placed in a row, the socks should overlap, not abut.
Stagger overlapping joints in adjacent rows by 5 to 10 feet.
Removal
■ For permanent installations: do not remove compost socks. Compost socks will degrade over time.
■ For temporary installations: remove sock, rope, and stakes if ordered by the Resident Engineer. Cut sock and empty contents in place.
Other Considerations
■ Compost may be pre-seeded before placement into the mesh tube to assist in establishing vegetation. Once established, vegetation root systems provide additional soil stability and runoff filtration.
■ Permanent compost sock applications are particularly advantageous below embankments, especially adjacent streams, by limiting re-entry and disturbance to sensitive areas.
■ Organic material in compost is important for pollutant removal and vegetation establishment. Organic content of the compost should range from 30 to 65 percent, depending on site conditions.
Maintenance and Inspection
■ Inspect compost socks before and after each rainfall event, and weekly year-round. ■ Remove sediment from behind the compost sock if sediment is 1/3 of compost sock height above ground.
■ Repair or adjust the compost sock if rills or other evidence of concentrated runoff occur beneath the sock.
■ Repair or replace compost socks if they become split, torn, or unraveled. ■ Add stakes if the compost sock slumps or sags.
■ Replace broken or split wood stakes.
■ Maintain compost socks to provide an adequate sediment-holding capacity and runoff velocity reduction.
Temporary Compost Stocks SC-11
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Compost Stocks SC-11 March 2024 4 of 5
SWPPP or WPCP
■ Compost socks must be discussed in Section 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP.
Temporary Compost Stocks SC-11
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Compost Stocks SC-11 March 2024 5 of 5
SC-12
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Foam Barrier SC-12 March 2024 1 of 4
Temporary Foam Barrier
Standard Symbol
Definition and Purpose
Temporary foam barriers are one type of flexible sediment barriers. They are synthetic alternatives to fiber rolls, compost socks, and straw bale barriers and consist of a geosynthetic fabric with a urethane foam-filled core and a fabric apron that helps prevent undermining and scour. These synthetic linear sediment barriers are generally more robust sediment controls than standard fiber rolls and may be appropriate for continuous use in stormwater collection areas.
Appropriate Applications
■ Along the perimeter of a project.
■ As check dams in ditches, channels, or other stormwater collection areas. ■ Down-slope of exposed soil areas.
■ At operational storm drains as a form of inlet protection. ■ Around temporary stockpiles.
■ On either paved surfaces or soil.
■ As a linear sediment control for SC-10, “Temporary Drain Inlet Protection.” Limitations
■ Frequent maintenance is required if sediment-laden discharges are upstream of the BMP to maintain operability.
Temporary Foam Barrier SC-12
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Foam Barrier SC-12 March 2024 2 of 4
Standards and Specifications
General Requirements
■ Temporary foam barriers must comply with Standard Specifications Sections 13-10.02I and 13-
10.03H.
■ Temporary foam barriers consist of:
− A urethane foam-filled core.
− Geosynthetic fabric cover and flap.
− Triangular, circular, or square cross section.
− Vertical height of at least 5 inches after installation. − Horizontal flap at least 8 inches in width.
− Length of at least 4 feet per unit.
− Ability to interlock separate units into a long barrier such that water will not flow between units.
■ Geosynthetic fabric for temporary foam barriers covers must have:
− Minimum grab break load of 200 pounds, per ASTM D4632. − Minimum apparent elongation of 15 percent, per ASTM D4632. − Average water flow rate of 100 to 150 gallons per minute per square foot, per ASTM D4491. − Minimum permittivity of 0.05 1/sec, per ASTM D4491.
− Maximum apparent opening size of the 40 U.S. standard sieve size, per ASTM D4751. − Minimum ultraviolet radiation resistance of 70% retained grab breaking load at 500 hours of exposure, per ASTM D4355.
■ Submit a Certificate of Compliance for flexible sediment barriers.
Installation
■ Remove obstructions from the ground, including rocks, clods, and debris greater than 1 inch in diameter.
■ Secure temporary foam barriers to pavement with either:
− 1-inch concrete nails, 1-inch washers, and solvent-free adhesive − Gravel-filled bags
− A combination of both of the above methods
■ Secure temporary foam barriers to soil with 6-inch nails and 1-inch washers. ■ Secure connection points of two adjacent sections of temporary foam barriers with two nails. ■ Do not pierce the foam core of the barrier with nails.
Temporary Foam Barrier SC-12
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Foam Barrier SC-12 March 2024 3 of 4
Maintenance and Inspection
■ Inspect temporary foam barriers before and after each rainfall event, and weekly year-round. ■ Maintain temporary foam barriers to provide sediment-holding capacity and to reduce concentrated flow velocities.
■ Repair or adjust the temporary foam barriers if rills or other evidence of concentrated runoff occur beneath it.
■ Repair or replace split, torn, or unraveled material. Add or replace posts, stakes, or fasteners as needed to prevent sagging or slumping.
■ Reattach any temporary foam barriers that detach from the pavement. ■ Remove sediment deposits if the sediment exceeds 1/3 of the height above the ground behind a foam barrier.
■ Remove all flexible sediment barriers once construction is complete.
SWPPP or WPCP
■ Flexible sediment barriers, such as temporary foam, must be discussed in Section 600.1.3 of the SWPPP or Section 30.2.2 of the WPCP.
Temporary Foam Barrier SC-12
Caltrans Stormwater Quality Handbooks Section 4
Construction Site BMP Manual Temporary Foam Barrier SC-12 March 2024 4 of 4
5-1
Section 5
Wind Erosion Control BMP
5.1 Wind Erosion Control
Wind erosion control consists of applying water or other dust palliatives as necessary to prevent or alleviate dust nuisance. Wind erosion control BMPs are shown in Table 5-1.
Table 5-1. Wind Erosion Control BMPs
ID BMP Name
WE-1 Wind Erosion Control
Other BMPs that are sometimes applied to DSAs to control wind erosion are BMPs SS-3 through SS-7, shown in Section 3 of this Manual; BMP TC-2, shown in Section 6; and BMP NS-7, shown in Section 7. The remainder of this section describes the working details for the wind erosion control BMP.
WE-1
Caltrans Stormwater Quality Handbooks Section 5
Construction Site BMP Manual Wind Erosion Control WE-1
March 2024 1 of 2
Wind Erosion Control
Standard Symbol
Definition and Purpose
■ Wind erosion control consists of applying water or other dust palliatives as necessary to prevent or alleviate erosion by the forces of wind. Dust control must be applied in accordance with Caltrans standard practices. Covering small stockpiles or areas is an alternative to applying water or other dust palliatives; see SS-7 for “Temporary Cover and Rolled Erosion Control Products.”
■ Must comply with local agencies, such as air quality management districts that require dust control plans or dust control permits, as well as any Clean Air Act requirements.
Appropriate Applications
This practice is generally implemented on all exposed soils subject to wind erosion.
Limitations
■ Effectiveness depends on soil, temperature, humidity, and wind velocity. ■ Chemically treated subgrades could cause soil to become water repellant, preventing infiltration or the long-term re-vegetation of the site.
Standards and Specifications
Standard Specification Section 10-5 contains general requirements for dust control. ■ Effective dust control is accomplished by applying dust palliatives, temporary soil stabilization BMPs, and/or tracking controls, and by managing stockpiles. ■ Dust palliatives are covered under Section 18 of the Standard Specifications. Acceptable dust palliatives include water, dust-control binders, and dust suppressants. Dust-control binders must comply with specifications for tackifier. Dust suppressants include petroleum-based organic Wind Erosion Control WE-1
Caltrans Stormwater Quality Handbooks Section 5
Construction Site BMP Manual Wind Erosion Control WE-1
March 2024 2 of 2
product, nonpetroleum-based organic product, hygroscopic product, and synthetic polymer emulsion.
■ If a dust suppressant or tackifier is used, submit a Dust Treatment Plan. Submit a Certificate of Compliance for dust suppressants, tackifiers, and fibers. ■ Identify and stabilize key access points with the use of tracking control BMPs. ■ Minimize the impact of dust by anticipating the direction of prevailing winds. ■ Temporary soil stabilization BMPs, such as SS-3, “Temporary Hydraulic Mulch;” SS-4, “Temporary Hydroseed;” SS-5, and “Temporary Soil Binder” also provide wind erosion control benefits.
■ Ensure proper implementation of BMPs WM-3, “Stockpile Management,” and SC-7, “Street Sweeping,” as these BMPs provide wind erosion control benefits. ■ Ensure that water is applied by means of pressure-type distributors or pipelines equipped with a spray system or hoses and nozzles to ensure even distribution. ■ All distribution equipment should be equipped with a positive means of shutoff. ■ Chemical dust suppression products could have environmental water quality impacts.
Depending on the product and the time of application, water quality sampling for non-visible pollutants should be assessed when a storm event is forecasted. ■ Many products are available for chemical or petroleum-based organics stabilization. These products should not create any adverse effects on stormwater, plant life, or groundwater and should meet all applicable regulatory requirements, including inspection, documentation, monitoring, and reporting.
■ Unless water is applied by means of pipelines, at least one mobile unit should be available at all times to apply water or dust palliative to the project. ■ If reclaimed water is used, the sources and discharge must meet California Department of Health Services water reclamation criteria and the RWQCB requirements. Non-potable water must not be conveyed in tanks or drainpipes that will be used to convey potable water, and there must be no connection between potable and non-potable supplies. Non-potable tanks, pipes, and other conveyances must be marked “NON-POTABLE WATER - DO NOT DRINK.” ■ Appendix B of this Manual includes additional information on selecting temporary soil stabilization products that could be used for wind erosion control.
Maintenance and Inspection
■ Check areas daily for erosion and visible dust.
■ Most water-based dust-control measures require frequent application. Obtain vendor or independent information on longevity of chemical dust suppression.
SWPPP or WPCP
■ Wind erosion control must be discussed in Sections 300 and 600.1.5 of the SWPPP or Section
30.2.4 of the WPCP
6-1
Section 6
Tracking Control BMP
6.1 Tracking Control
Tracking control consists of preventing or reducing vehicle tracking from entering a storm drain or watercourse. Tracking control BMPs are shown in Table 6-1.
Table 6-1. Tracking Control BMPs
ID BMP Name
TC-1 Temporary Construction Entrance
TC-2 Temporary Construction Roadway
TC-3 Entrance/Outlet Tire Wash
The remainder of this section describes the working details for the tracking control BMPs.
TC-1
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Entrance TC-1 March 2024 1 of 4
Temporary Construction Entrance
Definition and Purpose
A temporary construction entrance is defined as a point of entrance to a construction site that is stabilized to reduce the tracking of mud and sediment onto public roads by construction vehicles.
Appropriate Applications
■ Where dirt or mud can be tracked onto public roads.
■ Adjacent to water bodies.
■ Where poor soils are encountered.
■ Where dust is a problem during dry weather conditions.
Limitations
■ Site conditions will dictate design and need.
■ Limit the points of entrance/exit to the construction site. ■ Limit speed of vehicles to control dust.
Standards and Specifications
General Requirements
■ Temporary construction entrance must comply with Standard Specification Section 13-7.03 – “Temporary Construction Roadways and Entrances.”
■ Corrugated steel panels must be pressed or shop welded. They should have a slot or hook for coupling the panels together.
Temporary Construction Entrance TC-1
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Entrance TC-1 March 2024 2 of 4
■ Class 8 RSP fabric shall be used to line a temporary construction entrance/exit. Do not drive on the fabric until the rock is spread. Repair damaged fabric by placing new fabric over the damaged area with at least an 18-inch overlap on all edges. ■ Type A rock should be used for a Type 1 temporary construction entrance. Type A rock must comply with Section 13-7.03B (2) of the Standard Specifications. ■ Type B rock should be used for a Type 2 temporary construction entrance. Type B rock must comply with Section 13-7.03B (2) of the Standard Specifications. ■ Submit details for alternative construction entrances at least 5 business days before installation.
This may include alternatives for the sump and corrugated steel panels or to eliminate the sump.
Installation
■ Prepare the location for the temporary construction entrance/exit by:
− Removing vegetation and clearing debris.
− Grading the ground to a uniform plane.
− Removing sharp objects that could damage the fabric.
− Compacting the top 1.5 feet of soil to at least 90 percent relative compaction. ■ Construct the temporary construction entrance by (standard plans attached below):
− Placing the fabric along the length of the construction entrance/exit. − Overlapping fabric ends by at least 12 inches.
− Covering the fabric with rock within 24 hours.
− Spreading rock over the fabric in the direction of traffic. − Keeping a 6-inch layer of rock over the fabric to prevent damage from the spreading equipment.
■ For a Type 2 temporary construction entrance, place rock under the corrugated steel panels.
Use at least six corrugated steel panels for each entrance. Couple the panels together to prevent movement.
■ If a sump is used, install it within 20 feet of the temporary construction entrance.
Other Considerations
■ Implement BMP SC-7, “Street Sweeping” as required under Section 13-4.03F and 13-7 of the Standard Specifications.
■ Require all employees, subcontractors, and suppliers to use the temporary construction entrance. If the construction entrance has metal plates as part of the BMP, all vehicles must be required to use them.
■ Route runoff from temporary construction entrances through a sediment-trapping device before discharge.
■ Design a temporary construction entrance to support the heaviest vehicles and equipment that will use it.
Temporary Construction Entrance TC-1
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Entrance TC-1 March 2024 3 of 4
■ The use of asphalt concrete grindings is not allowed (high potential for leaching hydrocarbons) unless it complies with the Caltrans SWMP. Designate combination or single purpose entrances and exits to the construction site to maintain smooth flow of traffic.
Maintenance and Inspection
■ Inspect before, during and after each rainfall event, and weekly year-round. ■ Inspect immediate site access roads daily; implement SC-7, “Street Sweeping” as needed. ■ Remove aggregate, separate it, and dispose of sediment if temporary construction entrance is clogged with sediment.
■ Keep all temporary construction entrance ditches clear.
SWPPP or WPCP
Tracking control BMPs are to be included and discussed in Section 600.1.4 for the SWPPP and Section 30.2.3 of the WPCP.
Temporary Construction Entrance TC-1
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Entrance TC-1 March 2024 4 of 4
TC-2
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Roadway TC-2 March 2024 1 of 5
Temporary Construction Roadway
Standard Symbol
Definition and Purpose
A temporary construction roadway is a stabilized access road. It is designed to control dust and erosion created by vehicular tracking.
Appropriate Applications
■ Use construction roadways and short-term detour roads:
− Where mud tracking is a problem during wet weather.
− Where dust is a problem during dry weather.
− When road is adjacent to water bodies.
− Where poor soils are encountered.
− Where there are steep grades and additional traction is needed.
Limitations
■ Materials will likely need to be removed prior to final grading and stabilization. ■ Site conditions will dictate design and need.
■ May not be applicable to very-short-duration projects. ■ Limit speed of vehicles to control dust.
Temporary Construction Roadway TC-2
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Roadway TC-2 March 2024 2 of 5
Standards and Specifications
General Requirements
■ Refer to Standard Specification Section 13-7.03 for temporary roadway standards. ■ Class 10 RSP fabric must be used to line temporary construction roadways. Do not drive on the fabric until the rock is spread. Repair damaged fabric by placing new fabric over the damaged area with at least an 18-inch overlap on all edges.
■ Type A or Type B rock may be used for temporary construction roadways. Type A and B rock must comply with Standard Specifications Section 13-7.03B(2). Coordinate materials with those used for stabilized construction entrances. Refer to TC-1, “Temporary Construction Entrance/Exit.”
■ The use of cold mix asphalt, AC grindings, or blast furnace slag for stabilized construction roadways is not allowed (high potential to leach hydrocarbons) unless it complies with the Caltrans SWMP.
Installation
■ Prepare the location for the temporary roadway by:
− Removing vegetation and clear debris.
− Grading the ground to a uniform plane.
− Grading the ground surface to drain in a way that prevents runoff from leaving the construction site.
− Removing sharp objects that could damage the fabric.
− Compacting the top 1.5 feet of soil to at least 90 percent relative compaction. ■ Construct the temporary construction roadway by (standard plans attached below):
− Placing the fabric along the length of the roadway.
− Overlapping fabric ends by at least 12 inches.
− Covering the fabric with rock within 24 hours.
− Spreading rock over the fabric in the direction of traffic. − Keeping a 6-inch layer of rock over the fabric to prevent damage from the spreading equipment.
Other Considerations
■ Design stabilized access to support the heaviest vehicles and equipment that will use it. ■ Implement TC-1, “Temporary Construction Entrance” and TC-3, “Entrance/Outlet Tire Wash” in combination with temporary construction roadway for maximum tracking control.
Temporary Construction Roadway TC-2
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Roadway TC-2 March 2024 3 of 5
Maintenance and Inspection
■ Inspect before and after each rainfall event, and weekly year-round. ■ Inspect immediate site access roads daily; implement SC-7, “Street Sweeping” as needed. ■ Keep all temporary roadway ditches clear.
■ When no longer required, remove stabilized construction roadway and re-grade and re-vegetate as necessary.
SWPPP or WPCP
Tracking control BMPs are to be included and discussed in Section 600.1.4 of the SWPPP, or Sections 30.2.3 and 30.2.4 of the WPCP.
Temporary Construction Roadway TC-2
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Roadway TC-2 March 2024 4 of 5
Temporary Construction Roadway TC-2
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Construction Roadway TC-2 March 2024 5 of 5
TC-3
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Entrance/Outlet Tire Wash TC-3 March 2024 1 of 2
Temporary Entrance/Outlet Tire Wash
Standard Symbol
Definition and Purpose
A tire wash is an area located at stabilized construction access points to remove sediment from tires and undercarriages and to prevent sediment from being transported onto public roadways.
Appropriate Applications
■ On construction sites where construction vehicles may track dirt and mud onto public roads. ■ On a project-by-project basis with other BMPs when determined necessary and feasible by the Resident Engineer.
Limitations
■ Requires a supply of wash water and way to collect or capture tire wash area runoff. ■ Requires a turnout or doublewide exit to prevent entering vehicles from driving through the wash area.
Standards and Specifications
■ Require all employees, subcontractors, and others that leave the site with mud-caked tires and/or undercarriages to use the wash facility.
■ Incorporate with a temporary construction entrance/exit. See TC-1, “Temporary Construction Entrance.”
■ Construct on level ground when possible, on a pad of Type A or Type B rock. Either Class 8 or 10 RSP fabric should be placed below the rock.
■ Wash rack must be designed and constructed/manufactured for anticipated traffic loads. ■ Vehicle wash water is non-stormwater that requires management and disposal. See NS-8, “Vehicle and Equipment Cleaning.”
Temporary Entrance/Outlet Tire Wash TC-3
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Temporary Entrance/Outlet Tire Wash TC-3 March 2024 2 of 2
■ Provide a drainage ditch that will convey the runoff from the wash area to a sediment trapping device or similar device. The drainage ditch should be of sufficient grade, width, and depth to carry the wash runoff.
■ Implement BMP SC-7, “Street Sweeping” as needed.
■ Refer to TC-1, “Temporary Construction Entrance” for details regarding design and installation of construction entrances and exits to the project site.
Maintenance and Inspection
■ Inspect before rain events, daily during extended rain events, after each rain event, and weekly year-round.
■ Inspect immediate site access roads daily; implement SC-7, “Street Sweeping” as needed. ■ Remove accumulated sediment in wash rack and/or sediment trap to maintain system capacity and performance.
■ Inspect routinely for damage and repair as needed. Document non-stormwater (sediment trapping device or similar device) in appropriate inspection form.
SWPPP or WPCP
■ Temporary Entrance/Outlet Tire Wash is to be included and discussed in Section 600.1.4 of the SWPPP or Section 30.2.3 of the WPCP.
7-1
Section 7
Non-Stormwater Management BMP
7.1 Non-Stormwater Management
Non-stormwater management BMPs are source control BMPs that prevent pollution by limiting or reducing potential pollutants at their source before they come in contact with stormwater. These practices involve day-to-day operations of the construction site and are usually under the control of the Contractor. These BMPs are also referred to as “good housekeeping practices,” which involve keeping a clean, orderly construction site.
Table 7-1 lists the non-stormwater management BMPs. It is important to note that all these BMPs have been authorized by Caltrans for statewide use, and they must be implemented depending on the conditions/applicability of deployment described as part of the BMP.
Table 7-1. Non-Stormwater Management BMPs
ID BMP Name
NS-1 Water Conservation Practices
NS-2 Dewatering
NS-3 Paving, Sealing, Saw Cutting, Grooving and Grinding Activities NS-4 Temporary Stream Crossing
NS-5 Temporary Creek Diversion Systems
NS-6 Illegal Connection and Illicit Discharge Detection and Reporting NS-7 Potable Water/Irrigation
NS-8 Vehicle and Equipment Cleaning
NS-9 Vehicle and Equipment Fueling
NS-10 Vehicle and Equipment Maintenance
NS-11 Pile Driving
NS-12 Concrete Curing
NS-13 Material and Equipment Use Over Water
NS-14 Concrete Finishing
NS-15 Structure Removal Over or Adjacent to Water
The remainder of this section describes the working details for each of the non-stormwater management BMPs.
NS-1
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Water Conservation Practices NS-1 March 2024 1 of 2
Water Conservation Practices
Standard Symbol
Definition and Purpose
Water conservation practices are construction methods that minimize the use of water on site or use water in a manner that avoids causing runoff, erosion, and/or the discharge of pollutants to the storm drain system or receiving waters. Proper use of this BMP reduces or prevents nonstormwater discharges.
Appropriate Applications
Water conservation practices are implemented on all construction sites wherever water is used.
Limitations
■ If not implemented correctly, discharges may trigger reporting and monitoring requirements and delay construction work.
Standards and Specifications
■ Keep water equipment in good working condition.
■ Ensure tracking controls are implemented in, near, and around water truck filling areas. ■ Repair water leaks promptly.
■ Authorization is required for activities that could potentially discharge water into a storm drain system or receiving waters.
■ Avoid using water to clean construction areas. Do not wash paved areas with water. Paved areas and roadways should be swept and vacuumed in accordance with SC-7, “Street Sweeping.”
■ Apply water for dust control in accordance with Standard Specifications Section 10-4 – Water Usage and BMP WE-1, “Wind Erosion Control.”
Water Conservation Practices NS-1
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Water Conservation Practices NS-1 March 2024 2 of 2
■ Direct construction water runoff to areas where it can infiltrate into the ground or be collected and reused.
■ Manage run-on to minimize contact with job site.
■ Retain water spilled while filling water trucks within the designated water truck filling areas.
Prevent tracking from water trucks and other equipment. ■ Report discharges to the Resident Engineer immediately.
Maintenance and Inspection
■ Inspect water equipment areas at least weekly, prior to a forecasted rain event, daily during extended rain events, and post storm events.
■ Inspect non-stormwater BMPs daily when non-stormwater operations are ongoing. ■ Repair water equipment as needed.
SWPPP or WPCP
Water Conservation Practices must be discussed in Section 600.1.4 of the SWPPP or Section
30.3.1 of the WPCP.
NS-2
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Dewatering NS-2
March 2024 1 of 3
Dewatering
Standard Symbol
Definition and Purpose
Dewatering is a practice that manages the discharge of pollutants when non-stormwater and accumulated precipitation (stormwater) must be removed from a work location so that construction work may be accomplished.
Appropriate Applications
■ For collection and discharge of non-stormwater and stormwater (accumulated rainwater) from excavations or temporary containment facilities. Non-stormwater includes, but is not limited to, groundwater, dewatering of piles, water from cofferdams, water diversions, and water used during construction activities that must be removed from a work area. ■ To manage the removal of accumulated precipitation (stormwater) from depressed areas at a construction site.
■ Stormwater mixed with non-stormwater should be managed as non-stormwater.
Limitations
■ Dewatering operations for non-stormwater will require, and must comply with, applicable local permits, project-specific permits, and regulations.
■ Site conditions will dictate design and use of dewatering operations. ■ Avoid dewatering discharges where possible via infiltration, reusing the water for dust control, etc.
■ If the dewatering discharge is not subject to a regional permit and it is absent of pollutants in quantities that threaten to cause pollution or a nuisance, dewatering under Attachment J of the CGP can be used.
Dewatering NS-2
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Dewatering NS-2
March 2024 2 of 3
Standards and Specifications
General Requirements
■ Dewatering shall be conducted in accordance with the Caltrans “Field Guide to Construction Site Dewatering Manual” and Standard Specifications Section 13-4.03G. ■ A dewatering and discharge work plan shall be submitted at least 15 days before the start of dewatering activities that details the location of dewatering and discharge activities, quantity of water to be used, equipment, and discharge point. The dewatering and discharge work plan must conform to Standard Specifications Section 13-4.01C and 13-4.01G. ■ Dewatering discharges must not cause erosion, scour, or sedimentation that could impact natural bedding materials.
■ Discharge the water within the project limits. Dispose the water if it cannot be discharged within project limits due to site constraints or contamination. ■ Do not discharge stormwater or non-stormwater that has an odor, discoloration other than sediment, an oily sheen, or foam on the surface. Immediately notify the Resident Engineer upon discovering any such condition.
■ The RWQCB may require a separate NPDES permit for a dewatering operation. These permits will have specific testing, monitoring, and discharge requirements. ■ Discharges must comply with regional and watershed-specific discharge requirements. ■ Additional permits or permissions from other agencies may be required for dewatering cofferdams or diversions.
■ Dewatering records shall be kept with the SWPPP or WPCP and maintained for a minimum of 3 years after the construction project is terminated.
■ The controls discussed in this BMP address sediment only. If the presence of polluted water with hazardous substances is identified as polluted in the contract, the Contractor shall implement dewatering pollution controls as required by the contract documents. If the quality of water to be removed by dewatering is not identified as polluted in the Contract Documents but is later determined by observation or testing to be polluted, the Contractor shall notify the RE and comply with Standard Specifications Section 4-1.06 – “Differing Site Conditions.” Sediment Treatment
■ A variety of methods can be used to treat water during dewatering operations from the construction site. The size of particles present in the sediment and/or RWQCB Dewatering Permit or receiving water limitations on sediment are key considerations for selecting sediment treatment option(s); in some cases, the use of multiple devices may be appropriate. ■ Refer to the sediment treatment options described in Appendix B of the Field Guide to Construction Site Dewatering to determine the optimal method to achieve sediment removal. ■ Refer to the applicable project dewatering and/or stormwater permit for monitoring and sampling forms and requirements.
Dewatering NS-2
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Dewatering NS-2
March 2024 3 of 3
Maintenance and Inspection
■ Inspect dewatering operation areas at least weekly, prior to a forecasted rain event, daily during extended rain events, and post qualifying precipitation events. ■ Accumulated sediment removed during the maintenance of a dewatering device may be disposed outside the right-of-way in conformance with Standard Specifications Section 14-10 “Solid Waste Disposal and Recycling.”
■ Accumulated sediment commingled with other pollutants must be disposed in accordance with all applicable laws and regulations.
SWPPP or WPCP
Dewatering must be discussed in Section 600.2.1 of SWPPP and specific sample collection, collection, and parameters must be discussed in Section 1100 (if using Attachment J) or 1300 if required by a specific RWQCB Dewatering Permit or in Section 30.3.1 of the WPCP.
NS-3
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Paving, Sealing, Sawcutting, Grooving, and Grinding Activities NS-3 March 2024 1 of 4
Paving, Sealing, Sawcutting, Grooving, and
Grinding Activities
Standard Symbol
Definition and Purpose
Procedures and practices for conducting paving, sealing, sawcutting, and grinding activities to minimize the transport of pollutants to the storm drain system or receiving water body.
Appropriate Applications
These procedures are implemented where operations such as paving, surfacing, resurfacing, grinding, coring, grooving, sealing, or saw cutting generate spoils, residue, or process water that may pollute storm water runoff or discharge to the storm drain system or receiving water body.
Limitations
■ Activities related to paving, sealing, sawcutting, grooving, and grinding operations should be limited when precipitation is forecasted to prevent the triggering for visible and non-visible pollutant monitoring.
■ Discharges of freshly paved surfaces can raise pH and trigger permit violations.
Standards and Specifications
General Requirements
■ Refer to Standard Specifications Section 13-4.03E(7) – “Paving, Sealing, Sawcutting, Grooving, and Grinding Activities.”
■ Do not allow the following materials to enter the storm drain system or receiving waters:
cementitious material, asphaltic material, aggregate or screenings, sawcutting, grooving, Paving, Sealing, Sawcutting,
Grooving, and Grinding Activities NS-3
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Paving, Sealing, Sawcutting, Grooving, and Grinding Activities NS-3 March 2024 2 of 4
grinding residue, pavement chunks, shoulder backing, methacrylate resin, and sandblasting residue. This list is not exhaustive.
■ Drainage inlets shall be protected, and linear sediment barriers (such as silt fences, gravel bag berms, or fiber rolls) shall be used to protect receiving waters during operations related to paving, sealing, sawcutting, grooving, or grinding.
■ Drainage inlets and manholes shall be protected during application of seal coat, tack coat, slurry seal, and/or fog seal. Refer to SC-10, “Temporary Drainage Inlet Protection.” ■ Whenever precipitation is forecasted, limit paving, sawcutting, and grinding to places where runoff can be captured. Grinding or grooving of pavement shall not be conducted when precipitation is forecasted unless runoff can be captured. ■ Seal coat, tack coat, slurry seal, or fog seal shall not be applied when precipitation is forecasted during the application or curing period.
■ Slurry shall be removed with a vacuum immediately after it is produced and shall be prevented from running off the pavement or into lanes open to traffic. ■ The residue from grooving and grinding activities shall be collected with a vacuum attachment on the grinding machine and shall be prevented from flowing across the pavement. See also WM-8, “Concrete Waste Management,” and WM-10, “Liquid Waste Management.” ■ Material removed from existing roadways may be stockpiled, if allowed, away from drainage inlets and receiving waters in accordance with BMP WM-3, “Stockpile Management” and Standard Specifications Section 13-4.03C(3) –“Stockpile Management.”. No materials should be stockpiled or used in a manner that may result in an unauthorized discharge. ■ Drip pans or absorbent materials shall be placed under paving equipment when not in use.
Refer to WM-4, “Spill Prevention and Control.” Equipment shall be cleaned in accordance with NS-8, “Vehicle and Equipment Cleaning.”
■ Do not coat asphalt trucks and equipment with substances that contain soap, foaming agents, or toxic chemicals.
Asphalt Concrete and Concrete Pavement Handling
■ Prevent sand and gravel from entering streets, storm drains, and receiving waters. ■ Substances used to coat asphalt transport trucks, asphalt trucks, and asphalt spreading equipment shall not contain soap, foaming agents, or toxic chemicals. ■ Asphalt spoils must be recycled or disposed in accordance with WM-5, “Solid Waste Management,” and/or WM-6, “Hazardous Waste Management.” ■ AC and CC grindings, pieces, or chunks approved by the RE for reuse in embankments or shoulder backing shall not be at risk of entering storm drain systems or receiving waters. ■ Temporarily protect inlets and receiving waters until the structure is stabilized or permanent controls are in place.
■ The reuse of AC or PCC grindings, pieces, or chunks as road base must be placed at least 5 feet above the seasonal high groundwater elevation, with the approval of the Resident Engineer (RE). Shoulder backing containing recycled asphalt pavement shall not be placed within 100 Paving, Sealing, Sawcutting,
Grooving, and Grinding Activities NS-3
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Paving, Sealing, Sawcutting, Grooving, and Grinding Activities NS-3 March 2024 3 of 4
feet measured horizontally from a culvert, watercourse, or bridge and must comply with the SWMP.
■ During chip seal application and sweeping operations, petroleum or petroleum-covered aggregate must not be allowed to enter storm drains or receiving waters. Temporarily protect inlets and receiving waters until stabilized.
■ Clean asphalt-coated equipment off site whenever possible. When cleaning dry, hardened asphalt from equipment, manage hardened asphalt debris in accordance with WM-5, “Solid Waste Management,” and/or WM-6, “Hazardous Waste Management” and NS-8 “Vehicle and Equipment Cleaning,” whichever is applicable.
■ Allow aggregate rinse to settle. Then, either allow rinse water to dry in a temporary pit as described in WM-8, “Concrete Waste Management” or dispose in accordance with WM-5, “Solid Waste Management.”
Thermoplastic Striping and Pavement Markers
■ Contractor shall not pre-heat, transfer, or load thermoplastic within 50 feet of drainage inlets or receiving waters.
■ Do not unload, transfer, or load bituminous material for pavement markers within 50 feet of drainage inlets or receiving waters.
■ All thermoplastic striper and pre-heater equipment shutoff valves shall be inspected to ensure that they are working properly to prevent thermoplastic from leaking. ■ The pre-heater shall be filled carefully to prevent splashing or spilling of hot thermoplastic.
Leave 6 inches of space at the top of the pre-heater container when filling thermoplastic to allow room for material to move when the vehicle is deadheaded. ■ Melting tanks shall be loaded with care, with a minimum of 6 inches of freeboard in case of splashing when vehicle is deadheaded. When servicing or filling melting tanks, ensure all pressure is released before removing lids to avoid spills. ■ Immediately remove drips, overspray, improper markings, paint, and thermoplastic tracked by traffic with an authorized method.
■ Collect and dispose bituminous material from the roadway after removal of markers in accordance with WM-5, “Solid Waste Management.”
■ Clean truck beds daily of loose debris and melted thermoplastic. When possible, recycle thermoplastic material. Thermoplastic waste shall be disposed in accordance with BMP WM-5, “Solid Waste Management” and/or WM-6, “Hazardous Waste Management,” as applicable.
Maintenance and Inspection
■ Inspect and maintain machinery and BMPs regularly to minimize leaks and drips. ■ Ensure that employees and subcontractors are implementing appropriate measures during paving operations.
■ If project operations trigger the Industrial General Permit (IGP) (industrial operations located within project limits regardless of whether the facility is within or outside Caltrans’ right-of-way and outside Caltrans’ right-of-way but within project limits), ensure that any run-on or runoff from Paving, Sealing, Sawcutting,
Grooving, and Grinding Activities NS-3
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Paving, Sealing, Sawcutting, Grooving, and Grinding Activities NS-3 March 2024 4 of 4
IGP activities does not have potential to create pollution onto Caltrans right-of-way. Refer to SWMP for additional guidance.
SWPPP or WPCP
Paving, Sealing, Sawcutting, Grooving and Grinding operations must be discussed in Section 600.2.1 of the SWPPP or Section 30.3.1 of the WPCP.
NS-4
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Temporary Stream Crossing NS-4 March 2024 1 of 4
Temporary Stream Crossing
Standard Symbol
Definition and Purpose
A temporary stream crossing is a structure placed across a stream or water body that allows vehicles to cross during construction and helps minimize, reduce, or manage erosion and downstream sedimentation caused by the vehicles.
Appropriate Applications
■ Where appropriate regulatory permits have been secured and requirements strictly followed. ■ Where construction equipment or vehicles need to frequently cross a waterway. ■ When alternate access routes impose significant constraints. ■ When crossing perennial streams or waterways causes significant erosion. ■ Where construction activities will not last longer than 1 year.
Limitations
■ Typically, stream crossings require regulatory permits such as RWQCB 401 Certification, U.S.
Army Corps of Engineers 404 Permit, and approval by California Department of Fish and Wildlife.
■ If numerical-based water quality standards are mentioned in any of these regulatory permits, monitoring and water quality sampling may be required and must comply with Standard Specifications Section 13-11 – “Water Quality Monitoring” or the contract special provisions. If monitoring related to these numerical-based water quality standards is not addressed in the Contract Documents, contact the Resident Engineer.
■ Ensure that project-specific requirements from regulatory permits for the installation, removal or restoration of creek banks are fully implemented.
Temporary Stream Crossing NS-4
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Temporary Stream Crossing NS-4 March 2024 2 of 4
■ Will usually disturb the waterway during installation and removal. ■ Installation may require dewatering or temporary diversion of the stream. See NS-2, “Dewatering” and NS-5, “Clear Water Diversion.”
■ May become a constriction in the waterway, which can obstruct flood flow and cause flow backups or washouts. If improperly designed, flow backups can increase the pollutant load through washouts and scouring.
■ Use of natural or other gravel in the stream for construction of a cellular confinement system (CCS) ford crossing will be contingent upon approval by fisheries agencies. ■ Ford crossings may degrade water quality due to contact with vehicles and equipment. ■ A CCS should not be used in excessively high or fast flows. ■ Upon completion of construction activities, CCS blocks must be removed from stream.
Standards and Specifications
General Considerations
■ Location of the temporary stream crossing shall address:
■ Site selection where erosion potential is low.
■ Areas where the side slopes from highway runoff will not spill into the side slopes of the crossing.
■ The following types of temporary stream crossings shall be considered:
− Culverts - Used on perennial and intermittent streams. − Fords - Appropriate during the dry season in arid areas. Used on dry washes and ephemeral streams, and low-flow perennial streams. A CCS is also appropriate for use in streams. − Bridges - Appropriate for streams with high flow velocities, steep gradients, and/or where temporary restrictions in the channel are not allowed.
− Design and installation requires knowledge of stream flows and soil strength. Designs shall be prepared under direction of, and approved by, a registered civil and/or structural engineer. Both hydraulic and construction loading requirements shall be considered with the following:
− Comply with the requirements for culvert and bridge crossings, as contained in the Caltrans Highway Design Manual, particularly if the temporary stream crossing will remain during high flow periods.
− Provide stability in the crossing and adjacent areas to withstand the design flow. The design flow and safety factor shall be selected based on careful evaluation of the risks due to over topping, flow backups, or washout.
− Avoid using oil, AC, or other potentially hazardous waste materials for the temporary traveled surface over the stream crossing.
Temporary Stream Crossing NS-4
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Temporary Stream Crossing NS-4 March 2024 3 of 4
Construction Considerations
■ Stabilize construction roadways, adjacent work area, and stream bed against erosion. ■ Construct during dry periods to minimize stream disturbance and reduce costs. ■ Construct at or near the natural elevation of the stream bed to prevent potential flooding upstream of the crossing.
■ Install temporary sediment control BMPs in accordance with sediment control BMPs presented in Section 4 to minimize embankment scour due to flow conditions. ■ Vehicles and equipment shall not be driven, operated, fueled, cleaned, maintained, or stored in the wet or dry portions of a water body where wetland vegetation, riparian vegetation, or aquatic organisms may be destroyed, except as authorized by the construction project regulatory permits as necessary to complete the work.
■ Temporary water body crossings and encroachments shall be constructed to minimize scour.
Cobbles used for temporary water body crossings or encroachments shall be clean, rounded river cobble.
■ The exterior of vehicles and equipment that will encroach on the water body within the project shall be maintained free of grease, oil, fuel, and residues. ■ Disturbance or removal of vegetation shall not exceed the minimum necessary to complete operations. Precautions shall be taken to avoid damage to vegetation. Disturbed vegetation shall be replaced with the appropriate soil stabilization measures. Appropriate use of highvisibility fencing should be conducted and maintain in accordance with SS-2, “Preservation of Existing Vegetation.”
■ Riparian vegetation, when removed pursuant to the provisions of the work, shall be cut off no lower than ground level to promote rapid re-growth. Access roads and work areas built over riparian vegetation shall be covered by a sufficient layer of clean river-run cobble to prevent damage to the underlying soil and root structure. The cobble shall be removed upon completion of project activities.
■ Any temporary artificial obstruction placed within flowing water shall only be built from material, such as clean gravel, that will cause little or no siltation. ■ Drip pans shall be placed under all vehicles and equipment placed on docks, barges, or other structures over water bodies when the vehicle or equipment is planned to be idle for more than 1 hour.
Specific Considerations
■ Culverts are relatively easy to construct and able to support heavy equipment loads. ■ Fords are the least expensive of the crossings, with maximum load limits. ■ Temporary fords are not appropriate if construction will continue through a period of high flows if thunderstorms are likely, or if the stream is perennial. ■ CCS crossing structures consist of clean, washed gravel and cellular confinement system blocks. CCSs are appropriate for streams that would benefit from an influx of gravel, e.g., salmonid streams, streams or rivers below reservoirs, and urban channelized streams. Many urban stream systems, such as dams, gravel mines, and concrete channels, are graveldeprived due to human influences.
Temporary Stream Crossing NS-4
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Temporary Stream Crossing NS-4 March 2024 4 of 4
■ CCSs allow designers to use either angular or naturally occurring rounded gravel because the cells provide the necessary structure and stability. In fact, natural gravel is optimal for this technique because of the habitat improvement it will provide after removal of the CCS. ■ A gravel depth of 6 to 12 inches for a CCS structure is sufficient to support most construction equipment.
■ An advantage of a CCS crossing structure is that relatively little rock or gravel is needed because the CCS provides the stability.
■ Bridges are generally more expensive to design and construct but provide the least disturbance to the stream bed and constriction of the waterway flows.
Maintenance and Inspection
■ Periodically remove debris behind fords, in culverts, and under bridges. ■ Replace lost protective aggregate from inlets and outlets of culverts. ■ Remove temporary crossing promptly when it is no longer needed. ■ Inspection shall, at a minimum, occur weekly and after each significant rainfall, and include checking for:
− Blockage in the channel, debris buildup in culverts or behind fords, and under bridges. − Erosion of abutments, channel scour, riprap displacement, or piping in the soil. − Structural weakening of the temporary crossing, such as cracks, and undermining of foundations and abutments.
SWPPP or WPCP
Temporary Stream Crossing must be discussed in Section 600.2.1 of the SWPPP or Section 30.3 of the WPCP.
NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 1 of 12
Clear Water Diversion
Standard Symbol
Definition and Purpose
Clear water diversion consists of a system of structures and measures that intercept surface water runoff upstream of a project site, transport it around the work area, and discharge it downstream with minimal water quality degradation from either the project construction operations or the diversion’s construction. Clear water diversions are used to reduce sediment pollution from construction work occurring in or adjacent to water.
Isolation techniques are clear water diversion methods that isolate near-shore work from a waterbody. Structures commonly used as part of this system include diversion ditches, berms, dikes, slope drains, rock, gravel bags, wood, sheet piles, aqua barriers, cofferdams, filter fabric or turbidity curtains, drainage and interceptor swales, pipes, or flumes.
Appropriate Applications
■ A clear water diversion is typically implemented where appropriate permits have been secured and work must be performed in a live stream or water body. Work in jurisdictional waters typically require the following, at a minimum: Clean Water Act Section 401 (RWQCB Water Quality Certification), Clean Water Act Section 404, and Fish and Game Code Section 1600 permits.
■ Clear water diversions are appropriate for isolating construction activities occurring within or near a water body, such as streambank stabilization, or culvert, bridge, pier, or abutment installation. They may also be used in combination with other methods, such as clear water bypasses and/or pumps.
■ Implement SS-12, “Streambank Stabilization” to minimize impacts to streambanks. ■ Where working areas encroach on live streams, barriers adequate to prevent the flow of muddy water into streams should be constructed and maintained between working areas and streams.
During barrier construction, muddying of streams should be held to a minimum.
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 2 of 12
■ Channel diversions are appropriate for small streams where there is adequate right-of-way to create a temporary channel around a construction work area and geosynthetics or rock can be used to handle the shear stresses associated with the expected flows. ■ Berms are appropriate for small perennial, intermittent, or ephemeral streams with temporary culverts or pipe diversions. Berms may also be used to shift flows to one side or the other within a channel.
■ Gravel-bag berms (SC-6, “Temporary Gravel Bag/Earthen Berms”) are appropriate for smaller streams where the hydraulic forces and water pressure can be adequately addressed with the weight of gravel-filled bags and plastic sheeting. This method results in a cofferdam-like isolation from the receiving water.
■ Cofferdams are appropriate for small streams and lakes to confine flows to one side, create a dry work area, or to berm entire small streams. Typically, cofferdams are used in association with structures at Caltrans, though some inflatable cofferdams may be used for smaller applications.
■ Pumped diversions are suitable for short-term projects in intermittent and low-flow streams.
Excavation of a temporary bypass channel, or passing the flow through a pipe (called a flume) is appropriate for diverting streams less than 20 feet wide and with flow rates less than 100 cubic feet per second.
■ Piped diversions are appropriate for short-term projects with little base flow. ■ Water quality monitoring must typically be performed before and during in-water work, including the installation, operation, and removal of clear water diversions. Follow the requirements outlined in the Standard Specifications or special provisions.
Limitations
■ Diversion/encroachment activities will usually disturb the waterway during installation and removal of diversion structures.
■ Specific permit requirements or mitigation measures, such as those required by the U.S. Army Corps of Engineers, California Department of Fish and Wildlife, Federal Emergency Management Agency, RWQCB, etc., may be included in Contract Documents because of clear water diversion/ encroachment activities.
■ Diversion/encroachment activities may constrict the waterway, obstruct flood flows, and cause flooding or washouts. Diversion structures should not be installed without identifying potential impacts to the stream channel.
■ Diversion or isolation activities should not completely dam streamflow. ■ The designer should consider the stream size, depth of water, and risks for temporary stream diversion. Use this BMP and specification for small streams and low-risk projects. ■ Cofferdams and more elaborate systems should be designed by engineering services staff with the appropriate structural background or by the Contractor. The design decision and design parameters should be coordinated by the project engineers that all permitting and highway design requirements are met.
■ Dewatering and removal may require additional sediment control or water treatment (See NS-2, “Dewatering”).
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 3 of 12
■ Heavy equipment driven in wet portions of a water body to accomplish work should be completely clean of petroleum residue. Water levels should be below the gearboxes of the equipment in use, or lubricants and fuels sealed such that water inundation should not result in leaks.
■ Mechanical equipment operated in the water shall not be submerged to a point above any axle of said mechanical equipment.
■ Excavation equipment buckets may reach out into the water to remove or place fill materials.
Only the bucket of the crane/excavator/backhoe may operate in a water body. The main body of the crane/excavator/backhoe shall not enter the water body, except as necessary to cross the stream to access the work site.
■ Stationary equipment such as motors and pumps located within or adjacent to a water body shall be positioned over drip pans.
■ Equipment shall not be parked below the high-water mark unless allowed by a regulatory agency’s permit or approval.
■ Drip pans shall be placed under all vehicles, and equipment placed on docks, barges, or other structures over water bodies, when the vehicle or equipment is planned to be idle for more than 1 hour.
■ Where possible, avoid or minimize diversion/encroachment impacts by scheduling construction during periods of low flow or when the stream is dry. See also the project special provisions for scheduling requirements.
■ Scheduling shall also consider seasonal releases of water from dams, fish migration and spawning seasons, and water demands due to crop irrigation. ■ Materials and equipment should be moved from diversion work areas prior to forecasted rain events to prevent non-storm water discharges.
Standards and Specifications
General Requirements
■ Most small stream diversions can be designed by the district and coordinated with the HQ OHSD. In many cases, the diversion can be located on the plan sheet referencing the nonstandard specification for temporary creek diversion. ■ Many projects will have multiple culverts, so it may be appropriate to develop a table of the lump-sum costs for each system. This should be provided to the RE for use in reviewing the Temporary Creek Diversion System Plan to help determine if all needed items are included. ■ The types of diversion for small to medium-sized streams may include:
− Pumped systems
− Temporary culverts
− Inflatable cofferdams (consult HQ OHSD for specifications) ■ For larger (large rivers, lakes, bays, and ocean areas) temporary creek diversions that have a higher risk to worker safety and a more extensive design is required to address the forces for the depth and flow of the water, the district’s structures representative should be consulted for the design (e.g., larger rivers where coffer dams are required). The engineer must consult and Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 4 of 12
follow the Caltrans Engineering Services Shoring Guidance and consult with Construction as the owner of the specification.
− Diversion can be constructed from timber, soil, or steel, but in most cases are designed and constructed with steel sheet piles. Refer to Standard Specifications Section 19-3.01C(2) Cofferdams.
− Guidance: Caltrans Shoring Guide (Engineering Services) − Dewatering: Field Guide to Construction Site Dewatering; NS-2, “Dewatering;” and Section 13-4.03G of the Standard Specifications for use with cofferdams or other large in-water work.
− May need to treat or control seepage water prior to discharge; consult appropriate requirements for treatment design needs.
■ When any artificial obstruction is being constructed, maintained, or placed in operation, sufficient water shall, at all times, be allowed to pass downstream to maintain aquatic life. ■ Disturbance or removal of vegetation shall not exceed the minimum necessary to complete operations.
■ Disturbed vegetation shall be replaced with the appropriate soil stabilization measures and in accordance with the project’s special provisions.
■ Riparian vegetation, when removed pursuant to the provisions of the work, shall be cut off no lower than ground level to promote rapid re-growth. Access roads and work areas built over riparian vegetation shall be covered by a sufficient layer of clean river-run rock to prevent damage to the underlying soil and root structure. The rock shall be removed upon completion of project activities.
■ Construct diversion structures with materials free of potential pollutants such as soil, silt, sand, clay, grease, or oil.
■ Clear water diversions incorporating clean washed gravel may be appropriate for use in salmon spawning streams.
■ Coordination with a variety of functional units at the Caltrans may be required to implement.
Design Considerations
■ Determine if the construction of the temporary diversion system causes more environmental damage to the riparian, wetland, or 100-year floodplain area than constructing the project without the diversion BMP. This is a consideration for all projects, but is usually appropriate for short-term construction projects for temporary or ephemeral streams, where scheduling the project when the stream is dry may be more effective than the construction of a large diversion system in a sensitive environmental area, where construction equipment could disturb fragile vegetation, roots, sensitive species, soil structure, and root systems. ■ Stream hydrology considerations include stream channel geometry, tributary watershed area, stream bed material, and predicted flow rates during construction. Follow methods in HDM Section 810 for the appropriate methods and rates for sizing the temporary diversion system. ■ In the past, when sizing systems, many temporary diversion system guidance documents required mandatory minimum return storms for sizing the systems, for example the 2-year, 5- year, or 10-year, 24-hour return period. This can result in temporary diversion systems as large as the drainage system they are replacing and result in large impacts to the stream riparian Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 5 of 12
zone, with large, disturbed soil areas. Overly conservative approaches for the hydrology sizing to protect the environment can inadvertently cause other impacts to the environment. Each project should be sized for the appropriate risks and be based on regulatory restrictions. ■ In coordination with District Hydraulics, consider the consequences for diversion exceedance, including public and work safety, environmental, legal, regulatory permit requirements, costs, space, and schedule.
Hydrology Sizing Methods
■ The sizing of clear water diversion systems varies by the time of year, local hydrology, and duration of the diversion. If there is a prescriptive storm size in a permit document, design to the required event size. A 2-year, 24-hour storm event has been used by many as a default event, but recent studies have shown that this may oversize the system and cause more disturbance in the sensitive stream zone than is necessary.
■ Diversion structures must be adequately designed to accommodate fluctuations in water depth or flow volume due to tides, storms, flash floods, etc. Careful analysis of the local hydrology history and risk analysis is required to minimize the diversion impacts.
Temporary Diversions/Encroachments
■ Construct diversion channels in accordance with SS-9, “Earth Dikes/Drainage Swales, and Ditches.”
■ In high-flow-velocity areas, stabilize slopes of embankments and diversion ditches using an appropriate liner, in accordance with SS-12, “Streambank Stabilization,” and SS-7, “Temporary Cover & Rolled Erosion Control Products (RECP),” or use rock slope protection, as described in Standard Specifications Section 72 2 – “Rock Slope Protection.” ■ Where appropriate, use natural streambed materials such as large cobbles and boulders for temporary embankment/slope protection, or other temporary soil stabilization methods. ■ Provide for velocity dissipation at transitions in the diversion, such as the point where the stream is diverted to the channel and the point where the diverted stream is returned to its natural channel. See also SS-10, “Outlet Protection/Velocity Dissipation Devices.” Temporary Dry Construction Areas
■ When dewatering behind temporary structures to create a temporary dry construction area, such as cofferdams, pass pumped water through a sediment settling device, such as a portable tank, settling basin, or active treatment system if necessary before returning water to the water body; see NS-2, “Dewatering” and Standard Specifications Section 13-8 – “Temporary Active Treatment System.”
■ If the presence of polluted water or sediment is identified in the contract, the Contractor shall implement dewatering pollution controls as required by the Contract Documents. If the quality of water or sediment to be removed while dewatering is not identified as polluted in the Contract Documents but is later determined by observation or testing to be polluted, the Contractor shall notify the RE and comply with Standard Specifications Section 4-1.06 – “Differing Site Conditions.”
■ Any substance used to assemble or maintain diversion structures, such as form oil, shall be non-toxic and non-hazardous.
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 6 of 12
■ Any material used to minimize seepage underneath diversion structures, such as grout, shall be non toxic, non hazardous, and as close to a neutral pH as possible.
Instream Construction Sediment Control
There are three options currently available for reducing turbidity while working in a stream or river.
The stream can be:
■ Isolated from the area in which work is occurring by means of a water barrier. ■ Diverted around the work site through a pipe or temporary channel.
Additionally:
■ One can employ construction practices that minimize sediment suspension. ■ The highest hazard for sedimentation from instream construction generally occurs when the sediment control structure is being installed and when it is being removed. Generally, the best time to install the stream isolation or diversion structure is when the stream flow is low.
Conversely, the optimum time to remove in-stream diversion or isolation structures may be during the rising limb of a storm hydrograph. A probable “worst time” to release high total suspended solids (TSS) into a stream system with diminishing aquatic habitat might be when the stream flow is very low, e.g., summer low flow. During these times, the flow may be low while the biological activity in the stream is very high. On the other hand, the addition of shortterm spike in TSS or sediment during a big storm discharge might have a relatively low impact on the aquatic habitat or turbidity because the stream is already turbid, and the stream energy is capable of transporting both suspended solids and large quantities of bedload through the system.
Techniques to Minimize Total Suspended Solids
■ Padding. Padding laid in the stream below the work site may trap some solids that are deposited in the stream during construction. After work is done, the padding is removed from the stream and placed on the bank to assist in revegetation. ■ Clean, washed gravel. Using clean, washed gravel decreases solid suspension, as there are fewer small particles deposited in the stream.
■ Excavation using a large bucket. Each time a bucket of soil is placed in the stream a portion is suspended. Approximately the same amount is suspended whether a small or large amount of soil is placed in the stream. Therefore, using a large excavator bucket instead of a small one will reduce the total amount of soil that washes downstream. ■ Use of dozer for backfilling. Using a dozer for backfilling instead of a backhoe follows the same principles – the fewer times soil is deposited in the stream, the less soil will be suspended.
■ Partial dewatering with a pump. Partially dewatering a stream with a pump reduces the amount of water, and thus the amount of water that can suspend sediment.
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 7 of 12
Washing Fines
■ Partial washing fines is an “in-channel” sediment control method that uses water, either from a water truck or hydrant, to wash any stream fines that were brought to the surface of the channel bed during restoration back into the interstitial spaces of the gravel and cobbles. This technique is useful in both intermittent or ephemeral stream channels with gravelly to cobble substrate and may be useful in perennial streams just prior to removing isolation structures. ■ The purpose of this technique is to reduce or eliminate the discharge of sediment from the channel bottom during the first seasonal flows, or “first flush.” Sediment should not be allowed into stream channels; however, occasionally in-channel restoration work will involve moving or otherwise disturbing fines (sand and silt-sized particles) that are already in the stream, usually below bank-full discharge elevation. Subsequent re-watering (resumption of flows) of the channel can result in a plume of turbidity and sedimentation. ■ This technique washes the fines back into the channel bed. Bedload materials, including gravel cobbles, boulders, and those fines are naturally mobilized during higher storm flows. This technique is intended to delay the discharge until the fines would naturally be mobilized. ■ This technique should be used when construction work is required in channels. It is especially useful in intermittent or ephemeral streams in which work is performed “in the dry” and which subsequently become re-watered.
Prior to using this technique consider the following:
■ The stream must have sufficient gravel and cobble substrate composition. ■ This technique requires consideration of time of year and timing of expected stream flows. ■ The optimum time for the use of this technique is in the fall, prior to winter flows. ■ Consultation with, and approval from, the Department of Fish and Wildlife and the RWQCB may be required.
The following items should be considered when preparing project plans and specifications when this technique is used:
■ Apply sufficient water to wash fines but not cause further erosion or runoff. ■ Apply water slowly and evenly to prevent runoff and erosion. ■ Consult with Department of Fish and Wildlife and the RWQCB for specific water quality requirements of applied water (e.g., chlorine).
Isolation Techniques
Isolation techniques are methods that isolate near-shore work from a waterbody. Techniques include sheet pile enclosures, inflatable cofferdams like Aqua Dam, berms or gravel-bag berms (see SC-6, “Temporary Gravel Bag/Earthen Berm”) with impermeable membrane or plastic sheeting, gravel bags, cofferdams, and K-rail.
Filter Fabric Isolation Technique
A filter fabric isolation structure is a temporary structure built into a waterway to enclose a construction area and reduce sediment pollution from construction work in or adjacent to water.
This structure is composed of filter fabric, gravel-filled bags, and steel t-posts.
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 8 of 12
■ Filter fabric may be used for construction activities such as streambank stabilization, or culvert, bridge, pier, or abutment installation. It may also be used in combination with other methods, such as clean water bypasses and/or pumps.
■ This method involves placement of gravel bags or continuous berms to “key-in” the fabric, and subsequently staking the fabric in place.
■ If spawning gravel (gravel between 1 and 4 inches) is used, all other components of the isolation can be removed from the stream and the gravel can be spread out and left as salmon spawning habitat if permitted in the project’s 404 permit. Whether spawning gravel or other types of gravel are used, only clean washed gravel should be used as infill for the gravel bags or continuous berm.
■ This is a method that should be used in relatively calm water, and can be used in smaller streams.
■ Prior to using this technique consider the following:
− Do not use if the installation, maintenance, and removal of the structures will disturb sensitive aquatic species of concern.
− Not appropriate for projects where dewatering is necessary. − Not appropriate to completely dam streamflow.
■ The following items should be considered when preparing project plans and specifications when this technique is used:
− For the filter fabric isolation method, a non-woven or heavy-duty fabric (refer to Standard Specifications Section 96-1.02B) is recommended over standard silt fencing. Using rolled geotextiles allows non-standard widths to be used.
− Anchor filter fabric with gravel-filled bags filled with clean, washed gravel. Do not use sand.
If a bag should split open, the gravel can be left in the stream if permitted under the project’s 404 permit to provide aquatic habitat benefits.
− Another anchor alternative is a continuous berm, made with the continuous berm machine.
This is a gravel-filled bag that can be made in very long segments. Berm length is usually limited to 20 feet for ease of handling.
− Place the fabric on the bottom of the stream and place either a bag of clean, washed gravel or a continuous berm over the bottom of the fabric, such that a bag-width of fabric lies on the stream bottom. The bag should be placed on what will be the outside of the isolation area. − Pull the fabric up and place a metal t-post immediately behind the fabric on the inside of the isolation area; attach the fabric to the post with three diagonal nylon ties. − Continue placing fabric as described above until the entire work area has been isolated, staking the fabric at least every 6 feet.
− During construction, inspect daily during the work week. − Schedule additional inspections during storm events.
− Immediately repair any gaps, holes, or scour.
− Remove sediment buildup.
− Ensure pipe diversion is properly anchored to prevent shifting or leaking during use.
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 9 of 12
− Remove BMP upon completion of construction activity. Recycle or re-use if applicable. − Re-vegetate areas disturbed by BMP removal if needed.
Turbidity Curtain Isolation Technique
■ A turbidity curtain is a fabric barrier used to isolate the nearshore work area. The barriers are intended to confine the suspended sediment. The curtain is a floating barrier, and thus does not prevent water from entering the isolated area; rather, it prevents suspended sediment from getting out.
■ Turbidity curtains should be used where sediment discharge to a stream is unavoidable. They are used when construction activities adjoin quiescent waters, such as lakes, ponds, lagoons, bays, and slow-flowing rivers. The curtains are designed to deflect and contain sediment within a limited area and provide sufficient retention time so that the soil particles will fall out of suspension.
■ Prior to using this technique consider the following:
− Turbidity curtains should not be used in flowing water; they are best suited for use in quiescent ponds, lakes, lagoons, bays, and very-slow-moving rivers. − Turbidity curtains should not be placed across the entire width of a channel. − Removing sediment that has been deflected and settled out by the curtain may create a discharge problem through the re-suspension of particles and by accidental dumping by the removal equipment.
− Turbidity curtains may require a higher level of maintenance, adjustments, and relocation when deployed in comparison to structural isolation methods. However, turbidity curtains consist of flexible materials and may be repositioned and reconfigured as the limits of construction activity change.
■ The following items should be considered when preparing project plans and specifications when this technique is used:
− Turbidity curtains should be oriented parallel to the direction of flow wherever possible to avoid exerting excessive pressure on the fabric.
− The curtain should extend the entire depth of the watercourse in calm-water situations. − In wave conditions, the curtain should extend to within 1 foot of the bottom of the watercourse, such that the curtain does not stir up sediment by hitting the bottom repeatedly. If it is desirable for the curtain to reach the bottom in an active-water situation, a pervious filter fabric may be used for the bottom 1 foot. − The top of the curtain should consist of flexible flotation buoys, and the bottom shall be held down by a load line incorporated into the curtain fabric. The fabric shall be a brightly colored impervious mesh.
− The curtain shall be held in place by anchors placed at least every 100 feet, or as recommended by the manufacturer based on site-specific conditions, such as flow rate, wind speeds, currents, tidal influence, and wave action. − Place the anchors first, then tow the fabric out in a furled condition and connect to the anchors. The anchors should be connected to the flotation devices and not to the bottom of the curtain. Once in place, cut the furling lines, and allow the bottom of the curtain to sink. A Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 10 of 12
second set of anchors may be required in tidally influenced waters to secure the curtain against both the flow and ebb tides.
− Sediment that has been deflected and settled out by the curtain may be removed if so directed by the on-site inspector or the RE. Consideration must be given to the probable outcome of the removal procedure. It must be asked if it will create more of a sediment problem through re-suspension of the particles or by accidental dumping of material during removal. It is recommended that the soil particles trapped by the turbidity curtain only be removed if there has been a significant change in the original contours of the affected area in the watercourse.
− Particles should always be allowed to settle for a minimum of 6 to 12 hours prior to their removal or prior to removal of the turbidity curtain.
− The curtain should be inspected daily for holes or other problems; needed repairs should be made promptly.
− Allow sediment to settle for 6 to 12 hours prior to removal of sediment or curtain. This means that after removing sediment, wait an additional 6 to 12 hours before removing the curtain. − To remove, install furling lines along the curtain, detach from anchors, and tow out of the water. Water quality monitoring is typically required before removing the turbidity curtain to verify that the entrained water, sediment, and other potential contaminants such as sulfides would not violate a water quality standard when released.
K-rail River Isolation
■ This is temporary sediment control or stream isolation method that uses K-rails to form the sediment deposition area or to isolate the in-stream or near-bank construction area. ■ Barriers are placed end-to-end in a pre-designed configuration and gravel-filled bags are used at the toe of the barrier and also at their abutting ends to seal and prevent sediment movement beneath or through the barrier walls.
■ The K-rail isolation can be used in streams with higher water velocities than many other isolation techniques.
■ Prior to using this technique consider the following:
− The K-rail method does not allow for full dewatering. ■ The following items should be considered when preparing project plans and specifications when this technique is used:
− To create a floor for the K-rail, move large rocks and obstructions. Place washed gravel and gravel-filled bags to create a level surface on which K-rail will sit. − Place the bottom two K-rails adjacent to each other and parallel to the direction of flow; fill the center portion with gravel bags. Place the third K-rail on top of the bottom two; there should be sufficient gravel bags between the bottom K-rails such that the top one is supported by the gravel. Place plastic sheeting around the K-rails and secure at the bottom with gravel bags.
− Further support can be added by pinning and cabling the K-rails together. Also, large riprap and boulders can be used to support either side of the K-rail, especially where there is strong current.
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 11 of 12
− The barrier should be inspected at least once daily, and any damage, movement, or other problems should be addressed immediately.
− Sediment should be allowed to settle for at least 6 to 12 hours prior to removal of sediment, and for 6 to 12 hours prior to removal of the barrier.
Stream Diversions
■ Stream diversions consist of a system of structures and measures that intercept an existing stream upstream of the project, transports it around the work area, and discharges it downstream. The selection of which stream diversion technique to use depends on the type of work involved, physical characteristics of the site, and the volume of water flowing through the project.
■ Pumped diversions are appropriate in areas where de-watering is necessary. ■ Dam-type diversions may serve as temporary access to the site. ■ Appropriate where work areas require isolation from flows.
Prior to using this technique consider the following:
− Pumped diversions have limited flow capacity.
− Pumped diversions require frequent pump monitoring.
− Large flows during storm events can overtop dams.
− Flow diversion and re-direction with small dams involves in-stream disturbance and mobilization of sediment.
■ The following items should be considered when preparing project plans and specifications when this technique is used:
− Installation guidelines will vary based on existing site conditions and type of diversion used. − Diversions shall be sized to convey design flood flows. − Pump capacity must be sufficient for design flow; the upper limit is approximately 10 cubic feet per second (the capacity of two 8-inch pumps).
− Adequate energy dissipation must be provided at the outlet to minimize erosion. − Dam materials used to create dams upstream and downstream of the diversion should be erosion resistant; materials such as steel plate, sheet pile, sandbags, continuous berms, inflatable water bladders, etc., would be acceptable.
− When constructing a diversion channel, begin channel excavation at the proposed downstream end and work upstream. Once the watercourse to be diverted is reached and the excavated channel is stable, breach the upstream end and allow water to flow down the new channel. Once flow has been established in the diversion channel, install the diversion weir in the main channel; this will force all water to be diverted from the main channel. − Inspect diversion/encroachment structures before and after significant storms, and at least once per week while in service. Inspect daily during construction. − Pumped diversions require frequent pump monitoring.
Clear Water Diversion NS-5
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Clear Water Diversion NS-5 March 2024 12 of 12
− Inspect embankments and diversion channels before and after significant storms, and at least once per week while in service for damage to the linings, accumulating debris, sediment buildup, and adequacy of the slope protection. Remove debris, and repair linings and slope protection as required. Repair holes, gaps, or scour. − Upon completion of work, the diversion or isolation structure should be removed and flow should be re-directed through the new culvert or back into the original stream channel.
Recycle or re-use if applicable.
SWPPP or WPCP
Clear Water Diversion must be discussed in Section 600.2.1 of the SWPPP or Section 30.3 of the WPCP.
NS-6
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Illegal Connection and Illicit Discharge Detection and Reporting NS-6 March 2024 1 of 3
Illegal Connection and Illicit Discharge
Detection and Reporting
Standard Symbol
Definition and Purpose
Procedures and practices designed for construction contractors to recognize illegal connections, illicit discharges, or illegally dumped or discharged materials on a construction site, and for reporting incidents to the Resident Engineer (RE).
Appropriate Applications
■ Illegal connection and illicit discharge detection and reporting is applicable anytime an illegal connection or illicit discharge is discovered or illegally dumped material is found on the construction site.
■ This BMP applies to all construction projects.
Limitations
■ Illegal connections and illicit discharges or dumping, for the purposes of this BMP, refer to discharges and dumping caused by parties other than the Contractor. ■ Procedures and practices presented in this BMP are general. Contractor shall use extreme caution, immediately notify the RE when illegal connections or illicit dumping or discharges are discovered, and take no further action unless directed by the RE. ■ If pre existing hazardous materials or wastes are known to exist on site, the Contractor’s responsibility will be detailed in separate special provisions. The on-site area should be clearly marked and described in the SWPPP or WPCP.
Illegal Connection and Illicit
Discharge Detection and Reporting NS-6
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Illegal Connection and Illicit Discharge Detection and Reporting NS-6 March 2024 2 of 3
Standards and Specifications
Inspection
■ Inspect site before beginning the job for evidence of illegal connections or illicit dumping or discharges.
Illegal Connection and Illicit Discharge Detection and Reporting ■ Solids – Look for debris or trash piles. Solid waste dumping often occurs on roadways with light traffic loads or in areas not easily visible from the traveled way. ■ Liquids – Signs of illegal liquid dumping or discharge can include:
− Visible signs of staining or unusual colors to the pavement or surrounding adjacent soils. − Pungent odors coming from the drainage systems.
− Discoloration or oily substances in the water, or stains and residues detained within ditches, channels, or drain boxes.
− Abnormal water flow during the dry weather season.
■ Urban Areas – Evidence of illegal connections or illicit discharges is typically detected at storm drain outfall locations or manholes. Signs of an illegal connection or illicit discharge can include:
− Abnormal water flow during the dry weather season.
− Unusual flows in subdrain systems used for dewatering. − Pungent odors coming from the drainage systems.
− Discoloration or oily substances in the water, or stains and residues detained within ditches, channels, or drain boxes.
− Excessive sediment deposits, particularly adjacent to or near active off-site construction projects.
■ Rural Areas – Illegal connections or illicit discharges involving irrigation drainage ditches are detected by visual inspections. Signs of an illicit discharge can include:
− Abnormal water flow during the dry weather season.
− Non-standard drainage junction structures.
− Broken concrete or other disturbances at or near junction structures.
Reporting
■ Notify the RE of any illegal connections or illicit dumping or discharge incidents at the time of discovery. Do not take further action unless ordered.
■ The RE will notify the District Construction Stormwater Coordinator, who should coordinate with the NPDES Coordinator for reporting. Form MTCE-07 is used to document the initial investigation.
Illegal Connection and Illicit
Discharge Detection and Reporting NS-6
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Illegal Connection and Illicit Discharge Detection and Reporting NS-6 March 2024 3 of 3
Inspection, Cleanup and Removal
■ The Contractor is not responsible for investigation and cleanup of illegal connections or illicit discharges or dumping not generated by the Contractor. Caltrans may direct the Contractor to clean up non hazardous dumped or discharged material on the construction site. Assume that unlabeled or unidentifiable material is hazardous.
■ Inspect the entire project site at least weekly to check for illegal connections or illicit discharges.
SWPPP or WPCP
Illegal Connection and Illicit Discharge Detection and Reporting must be discussed in Section 600.2.1 of the SWPPP or Section 30.3.1 of the WPCP.
NS-7
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Potable Water/Irrigation NS-7 March 2024 1 of 2
Potable Water/Irrigation
Standard Symbol
Definition and Purpose
Potable water/irrigation management consists of practices and procedures to manage the discharge of potential pollutants generated during discharges from irrigation water lines, landscape irrigation, lawn or garden watering, planned and unplanned discharges from potable water sources, water line flushing, and hydrant flushing.
Appropriate Applications
Implement this BMP whenever the above activities or discharges occur at or enter a construction site.
Limitations
None identified.
Standards and Specifications
■ Inspect irrigated areas within the construction limits for excess watering. Adjust watering times and schedules to ensure that the appropriate amount of water is being used and to minimize runoff. Consider factors such as soil structure, grade, relative compaction, time of year, and type of plant material in determining the proper amounts of water for a specific area. ■ Take precautions to prevent irrigation water from eroding soil, wetting vehicles and pavement, or otherwise causing sediment, hydrocarbons, and other non-visible pollutants that accumulate on those surfaces to discharge into a storm drain system or receiving waterbody. ■ When possible, discharges from water line flushing, temporary active treatment systems (see Appendix C “Temporary Active Treatment System) should be reused for landscaping purposes. ■ Resident Engineer (RE) approval is required before beginning any washing activities that could discharge to the storm drain or receiving waterbody.
Potable Water/Irrigation NS-7
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Potable Water/Irrigation NS-7 March 2024 2 of 2
■ Where possible, direct water from off-site sources around or through a construction site in a way that minimizes contact with the construction site.
■ Perform pressure tests on the irrigation system supply lines to test for leaks, which could result in erosion or runoff if breached.
■ Shut off the water source to broken lines, sprinklers, or valves as soon as possible to prevent excess water flow.
■ Protect downstream storm water drainage systems and receiving waters from water pumped or bailed from trenches excavated to repair water lines.
Maintenance and Inspection
■ Repair broken water lines as soon as possible or as directed by the RE. ■ Inspect irrigated areas regularly for signs of erosion and/or discharge.
SWPPP or WPCP
■ Potable water/irrigation must be discussed in Section 600.2.1 of the SWPPP or Section 30.3 of the WPCP.
NS-8
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Vehicle and Equipment Cleaning NS-8 March 2024 1 of 2
Vehicle and Equipment Cleaning
Standard Symbol
Definition and Purpose
Vehicle and equipment cleaning procedures and practices are used to minimize or eliminate the discharge of pollutants from vehicle and equipment cleaning operations to storm drain systems or to watercourses.
Appropriate Applications
These procedures are applied on all construction sites where vehicle and equipment cleaning is performed.
Limitations
■ This BMP may be limited or disallowed under regulatory agency permits, particularly near environmentally sensitive areas.
■ Generates non-stormwater that requires management and, in some cases, the disposal of hazardous waste.
Standards and Specifications
General Requirements
■ Limit vehicle and equipment cleaning or washing at the job site except for the safety and protection of the equipment and as needed to comply with regulatory agency permits and approvals.
■ Cleaning of vehicles and equipment with soap, solvents, or steam shall not occur on the job site unless the RE has been notified in advance and the resulting wastes are fully contained in accordance with Standard Specifications Section 14-11 or 13-4.03D(5), whichever is applicable.
Do not use diesel to clean vehicles, and minimize the use of solvents.
Vehicle and Equipment Cleaning NS-8
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Vehicle and Equipment Cleaning NS-8 March 2024 2 of 2
■ Vehicle and equipment wash water shall be contained for percolation or evaporative drying away from storm drain inlets or receiving waters and should not be discharged within the highway right-of-way. Apply other appropriate BMPs as applicable. ■ All vehicles/equipment that regularly enter and leave the construction site must be cleaned off site.
■ Resulting wastes and by-products shall not be discharged or buried within the highway right-ofway, but must be captured and recycled or disposed according to the requirements of WM 10, “Liquid Waste Management” or WM-6, “Hazardous Waste Management,” depending on the waste characteristics.
Implementation
■ When vehicle/equipment washing/cleaning must occur on site and the operation cannot be located within a structure or building equipped with appropriate disposal facilities, the outside cleaning area shall have the following characteristics, and shall be arranged with the QSD or WPC Manager:
− Located away from storm drain inlets, drainage facilities, or watercourses. − Paved with concrete or asphalt, and bermed to contain wash waters and to prevent run-on and run off.
− Configured with a sump to allow collection and disposal of wash water. − Wash waters shall not be discharged to storm drains or watercourses. − Used only when necessary.
■ When cleaning vehicles/equipment with water:
− Use as little water as possible. High-pressure sprayers may use less water than a hose and shall be considered.
− Use positive shutoff valve to minimize water usage.
− Facility wash racks shall discharge to a sanitary sewer, recycle system, or other approved discharge system; they shall not discharge to the storm drainage system or watercourses.
Maintenance and Inspection
■ The control measure shall be inspected at least weekly, prior to a forecasted rain event, daily during extended rain events, and post-qualifying precipitation events. ■ Inspect wash area and sump regularly. Remove liquids and sediment as needed or as directed by the Resident Engineer.
SWPPP or WPCP
■ Vehicle equipment cleaning must be discussed in Section 600.2.1 of the SWPPP or Section
30.3.1 of the WPCP.
NS-9
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Vehicle and Equipment Fueling NS-9 March 2024 1 of 2
Vehicle and Equipment Fueling
Standard Symbol
Definition and Purpose
Vehicle and equipment fueling procedures and practices are designed to minimize or eliminate the discharge of fuel spills and leaks into storm drain systems or to receiving waters.
Appropriate Applications
These procedures are applied on all construction sites where vehicle and equipment fueling takes place.
Limitations
■ This BMP may be limited or disallowed under regulatory agency permits, particularly near environmentally sensitive areas.
■ On-site vehicle and equipment fueling should only be used where it is impractical to send vehicles and equipment off-site for fueling.
Standards and Specifications
■ When fueling must occur on site, the contractor shall select and designate an area or areas to be used, subject to approval of the Resident Engineer.
■ Dedicated fueling areas shall be protected from stormwater run-on and runoff, and shall be located at least 50 feet from downstream drainage facilities and watercourses. Fueling must be performed on level-grade areas.
■ Protect fueling areas with berms or dikes to prevent run-on, runoff, and to contain spills. ■ For long-term projects, consider constructing roofs or using portable tents over maintenance and fueling areas.
Vehicle and Equipment Fueling NS-9
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Vehicle and Equipment Fueling NS-9 March 2024 2 of 2
■ Absorbent spill clean-up materials and spill kits shall be available in fueling areas and on fueling trucks. These materials should be used on small spills instead of hosing down or burying techniques. Affected absorbent material and spill kits should be removed promptly and disposed properly after use.
■ Drip pans or absorbent pads shall be readily available during vehicle and equipment fueling. ■ Vehicle and equipment fueling areas shall not be left unattended during fueling activities. ■ Nozzles used in vehicle and equipment fueling shall be equipped with an automatic shutoff to control drips.
■ Use vapor recovery nozzles to help control drips, as well as air pollution where required by the air quality management districts.
■ Ensure the nozzle is secured upright when not in use. ■ Fuel tanks shall not be “topped off.”
■ Federal, state, and local requirements shall be observed for any stationary above-ground storage tanks. Refer to WM-1, “Material Delivery and Storage” for specifics as to what needs to be included for BMP protection.
■ Portable fuel canisters should be kept in a flammable cabinet when not in use.
Maintenance and Inspection
■ Vehicles and equipment shall be inspected on each day of use for leaks. Leaks shall be repaired immediately, or problem vehicles or equipment shall be removed from the project site. ■ Fueling areas and storage tanks shall be inspected at least weekly, prior to a forecasted rain event, daily during extended rain events, and post-storm events. ■ Immediately clean up spills and properly dispose contaminated soil and cleanup materials.
SWPPP or WPCP
■ Vehicle and equipment fueling must be discussed in Section 600.2.1 of the SWPPP or Section
30.3.1 of the WPCP.
NS-10
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Vehicle and Equipment Maintenance NS-10 March 2024 1 of 2
Vehicle and Equipment Maintenance
Standard Symbol
Definition and Purpose
Procedures and practices to minimize or eliminate the discharge of pollutants to the storm drain systems or to receiving waters from vehicle and equipment maintenance activities.
Appropriate Applications
■ These procedures apply on all construction projects where an on-site uncovered yard area is necessary for storage and maintenance of heavy equipment and vehicles.
Limitations
■ This BMP may be limited or disallowed under regulatory agency permits, particularly near environmentally sensitive areas.
■ On-site vehicle and equipment maintenance should only be used where it is impractical to send vehicles and equipment off site for fueling.
Standards and Specifications
■ When maintenance must occur on site, the contractor shall select and designate an area to be used, subject to approval of the Resident Engineer and implement appropriate controls for the activities to be performed.
■ Dedicated maintenance areas shall be on level ground and protected from storm water run-on and runoff, and shall be located at least 50 feet from downstream drainage facilities and receiving waters.
■ Protect maintenance areas with berms or dikes to prevent run-on, runoff, and to contain spills. ■ For long-term projects, consider constructing roofs or using portable tents over maintenance areas.
Vehicle and Equipment Maintenance NS-10
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Vehicle and Equipment Maintenance NS-10 March 2024 2 of 2
■ Absorbent spill cleanup materials and spill kits shall be available in maintenance areas. They should be used on small spills instead of hosing down or burying techniques. Affected absorbent material and spill kits should be removed promptly and disposed properly after use. ■ Drip pans or absorbent pads shall be placed under vehicles and equipment when performing maintenance work that involves fluids. Vehicles and equipment maintenance areas shall not be left unattended during maintenance activities.
■ Drip pans or plastic sheeting shall be placed under all vehicles and equipment placed on docks, barges, or other structures over water bodies when the vehicle or equipment is planned to be idle for more than 1-hour.
■ Properly dispose or recycle used batteries and tires, as well as any other vehicle or equipment parts.
■ Substances used to coat asphalt transport trucks and asphalt-spreading equipment shall be non-toxic.
■ Properly dispose of used oils, fluids, lubricants, and spill cleanup materials. ■ Do not dump fuels and lubricants onto the ground.
■ Do not place used oil in a dumpster or pour into a storm drain or watercourse. ■ Do not bury used tires.
■ Repair fluid and oil leaks immediately.
■ Provide spill containment dikes or secondary containment around stored oil and chemical drums. Refer to WM-1, “Material Delivery and Storage” for details.
Maintenance and Inspection
■ Vehicles and equipment shall be inspected on each day of use for leaks. Leaks shall be repaired immediately or removed from the project site.
■ Maintenance areas and storage tanks shall be inspected regularly. ■ Maintain waste fluid containers in leak-proof condition. ■ Inspect equipment for damaged hoses and leaky gaskets routinely. Repair or replace as needed.
■ Inspection and maintenance of vehicle and equipment maintenance areas must be properly documented, and the WPC manager must ensure no potential for discharges occur from these areas as part of the non-visible monitoring requirements.
SWPPP or WPCP
■ Vehicle and equipment maintenance must be discussed in Section 600.2.1 of the SWPPP or Section 30.3 of the WPCP.
NS-11
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Pile Driving Operations NS-11 March 2024 1 of 2
Pile Driving Operations
Standard Symbol
Definition and Purpose
The construction and retrofit of bridges and retaining walls often include driving piles for foundation support and shoring operations. Driven piles are typically constructed of concrete, steel, or timber.
Driven sheet piles are used for shoring and cofferdam construction. Proper control and use of equipment, materials, and waste products from pile driving operations will reduce the discharge of potential pollutants to the storm drain system or receiving waters.
Appropriate Applications
These procedures apply to construction sites near or adjacent surface waters or groundwater where permanent and temporary pile-driving operations (impact and vibratory) take place, including operations using pile shells for construction of cast-in-steel-shell and cast-in-drilled-hole piles.
Limitations
None identified.
Standards and Specifications
■ Have spill kits and cleanup materials available at all pile driving locations. Refer to WM-4, “Spill Prevention and Control.”
■ Place drip pans, absorbent pads, or plastic sheeting with absorbent material under vehicles and equipment performing pile-driving activities. Refer to NS-9, “Vehicle and Equipment Fueling” and NS-10, “Vehicle and Equipment Maintenance.”
■ Protect pile-driving equipment, including hammers and other hydraulic attachments, by parking them on plywood and covering them with plastic sheeting when precipitation is forecasted. ■ When not in use, store pile-driving equipment on level ground away from concentrated flows of storm water, drainage courses, and inlets.
Pile Driving Operations NS-11
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Pile Driving Operations NS-11 March 2024 2 of 2
■ Use less-hazardous vegetable oil instead of hydraulic fluid when practicable. ■ Keep leak free all equipment that is in use in streambeds, or on docks, barges, or other structures over water bodies. The storage or use of equipment in streambeds or other water bodies shall comply with all applicable regulatory permits. Refer to NS-13, “Material and Equipment Use Over Water.”
■ Implement other BMPs as applicable, such as NS-2, “Dewatering;” WM-5, “Solid Waste Management;” WM-6, “Hazardous Waste Management;” and WM-10, “Liquid Waste Management.”
Maintenance and Inspection
■ Inspect pile-driving areas and equipment for leaks and spills daily when they are in operation or within or next to water.
■ Inspect pile-driving areas and equipment for leaks and spills at least weekly, prior to a forecasted rain event, daily during extended rain events, and post storm events. Depending on the specific operations; daily inspection may be required. ■ Inspect equipment routinely and repair equipment as needed (e.g., worn or damaged hoses, fittings, gaskets).
■ Inspection and maintenance of these areas must be properly documented, and the WPC manager must ensure no potential for discharges occurs from these areas as part of the nonvisible monitoring requirements.
SWPPP or WPCP
■ Pile-driving operations must be discussed in Section 600.2.1 of the SWPPP or Section 30 of the WPCP.
NS-12
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Concrete Curing NS-12
March 2024 1 of 2
Concrete Curing
Standard Symbol
Definition and Purpose
Concrete curing is used in the construction of structures such as bridges, retaining walls, and pump houses. Concrete curing includes the use of both chemical and water methods. Proper procedures to minimize any potential for runoff during concrete curing must take place.
Appropriate Applications
All concrete elements of a structure (e.g., footings, columns, abutments, stems, soffit, deck) are subject to curing requirements.
Limitations
None identified.
Standards and Specifications
Chemical Curing
■ Avoid over-spray of curing compounds.
■ Minimize the drift of chemical cure as much as possible by applying the curing compound close to the concrete surface. Apply an amount of compound that covers the surface but does not allow any compound runoff.
■ Use proper storage and handling techniques for concrete curing compounds. Refer to WM-1, “Material Delivery and Storage.”
Concrete Curing NS-12
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Concrete Curing NS-12
March 2024 2 of 2
■ Protect drain inlets before applying curing compounds. Refer to SC-10, “Temporary Drainage Inlet Protection.”
■ Implement WM-4, “Spill Prevention and Control.”
Water Curing for Bridge Decks, Retaining Walls, and Other Structures ■ Direct cure water away from inlets and receiving waters to collection areas for removal as approved by the RE and in accordance with all applicable permits. ■ Collect cure water and transport or dispose water in accordance with all applicable permits ■ Use wet blankets or a similar method that maintains moisture while minimizing the use and possible discharge of water.
Maintenance and Inspection
■ Ensure that employees and subcontractors implement appropriate measures for storage, handling, and use of curing compounds.
■ Inspect any temporary diversion devices, lined channels, or swales for washouts, erosion, runoff, or debris. Replace lining and remove debris as necessary. ■ Inspect cure containers and spraying equipment for leaks. Also, inspect concrete curing areas daily when there are ongoing operations.
■ The WPC Manager must ensure no concrete curing activities occur when rain is forecasted that could lead to a discharge.
SWPPP or WPCP
■ Concrete curing must be discussed in Section 600.2.1 of the SWPPP or Section 30.3.1 of the WPCP.
NS-13
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Material and Equipment Use Over Water NS-13 March 2024 1 of 2
Material and Equipment Use Over Water
Standard Symbol
Definition and Purpose
Procedures for the proper use, storage, and disposal of materials and equipment on barges, boats, temporary construction pads, or similar locations that minimize or eliminate the discharge of potential pollutants into storm drain inlets or receiving waters.
Appropriate Applications
These procedures shall be implemented for construction materials and wastes (solid and liquid) and any other materials that may be detrimental if released. Applies where materials and equipment are used on barges, boats, docks, and other platforms over or adjacent a watercourse.
Limitations
Specific requirements may be included in the Contract Documents and permit documents associated with regulatory agencies, such as the Regional Water Quality Control Board (RWQCB), U.S. Army Corps of Engineers, and California Department of Fish and Wildlife.
Standards and Specifications
■ Measures to prevent the discharge of potential pollutants into storm drain inlets or receiving waters while operating equipment or using materials over water are considered BMPs by the regulatory agencies and should be documented in the SWPPP. ■ Implement this BMP in accordance with all necessary permits required for construction within or near receiving waters, such as RWQCB, U.S. Army Corps of Engineers, Department of Fish and Wildlife, and other local permitting agencies.
Material and Equipment Use Over Water NS-13
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Material and Equipment Use Over Water NS-13 March 2024 2 of 2
■ Place drip pans and absorbent materials under equipment and vehicles and ensure that an adequate supply of spill clean-up materials are on site in accordance with a spill response plan, if applicable. Ensure that staff are trained regarding the deployment of the spill response plan. ■ Drip pans shall be placed under all vehicles and equipment placed on docks, barges, or other structures over water bodies when the vehicle or equipment is expected to be idle for more than 1 hour.
■ Install watertight curbs or toe boards to contain spills and prevent materials, tools, and debris from falling off the barge, platform, dock, etc.
■ Secure all materials to prevent discharges to receiving waters via wind. ■ Discharges to receiving waters shall be reported to the Resident Engineer immediately upon discovery.
■ Maintain vehicles and equipment in accordance with NS-10, “Vehicle and Equipment Maintenance.” If a leaking line cannot be repaired, remove equipment from over the water and repair immediately.
■ Collect and contain demolished material in accordance with NS-15, “Structure Removal Over or Adjacent to Water.”
■ Refer to WM-1, “Material Delivery and Storage” and WM-4, “Spill Prevention and Control.” ■ Ensure the timely and proper removal of accumulated wastes over water. Refer to WM-5, “Solid Waste Management” and WM-6, “Hazardous Waste Management.” Maintenance and Inspection
■ Inspect vehicles and equipment for leaks and spills daily when they are in operation; make necessary repairs.
■ Ensure that employees and subcontractors implement appropriate measures for storage and use of materials and equipment.
■ Inspect and maintain all associated BMPs and perimeter controls to ensure continuous protection of the watercourse.
■ Inspect materials and equipment for leaks and spills at least weekly, prior to a forecasted rain event, daily during extended rain events, and post storm events. ■ Inspect equipment routinely and repair equipment as needed (e.g., worn or damaged hoses, fittings, gaskets).
■ Inspection and maintenance of these areas must be properly documented and ensure no potential for discharges from these areas as part of the non-visible monitoring requirements.
SWPPP or WPCP
Material and equipment use over water must be discussed in Section 600.2.1 of the SWPPP or Section 30.3.1 of the WPCP.
NS-14
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Concrete Finishing NS-14
March 2024 1 of 2
Concrete Finishing
Standard Symbol
Definition and Purpose
Concrete finishing methods are used for bridge deck rehabilitation, paint removal, curing compound removal, and final surface finish appearances. Methods include sand blasting, shot blasting, grinding, or high-pressure water blasting. Proper procedures minimize the impact that concrete finishing methods may have on runoff.
Appropriate Applications
These procedures apply to all construction locations where concrete finishing operations are performed.
Limitations
Specific permit requirements may be included in the contract documents for certain concrete finishing operations.
Standards and Specifications
General Requirements
■ Follow containment requirements stated in the project special provisions. ■ Collect and properly dispose of water and solid waste from high-pressure water blasting operations.
■ Collect and properly dispose of water from water blasting operations, and sand and solid waste from sandblasting operations.
■ Protect drainage inlets within 50 feet of the sandblasting prior to beginning sandblasting operations. Refer to SC-10, “Temporary Drainage Inlet Protection.” Concrete Finishing NS-14
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Concrete Finishing NS-14
March 2024 2 of 2
■ Implement SC-7, “Street Sweeping” within the sandblasting and surrounding area. ■ Minimize the drift of dust and blast material as much as possible by keeping the blasting nozzle close to the surface.
■ Discharges to waterways shall be reported to the Resident Engineer (RE) immediately upon discovery.
Other Considerations
■ Direct water from blasting operations away from inlets and receiving waters to collection areas for removal (e.g., dewatering) as approved in advance by the RE and in accordance with applicable permits.
■ When blast residue contains a potentially hazardous waste, refer to WM-6, “Hazardous Waste Management.”
■ Implement WM-8, “Concrete Waste Management” in combination with this BMP.
Maintenance and Inspection
■ At a minimum, inspect containment structures, if any, for damage or voids prior to use each day and prior to a likely forecasted storm event.
■ At the end of each work shift, remove and contain the liquid and solid wastes from containment structures, if any, and from the general work area.
■ Inspect concrete finishing areas at least weekly, prior to a forecasted rain event, daily during extended rain events, and post qualifying precipitation events. ■ Inspection and maintenance of these areas must be properly documented and ensure no potential for discharges from these areas as part of the non-visible monitoring requirements.
SWPPP or WPCP
Concrete Finishing must be discussed in Section 600.2.1 of the SWPPP or Section 30.3.1 of the WPCP.
NS-15
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Structure Demolition/Removal Over or Adjacent to Water NS-15 March 2024 1 of 3
Structure Demolition/Removal Over or Adjacent
to Water
Standard Symbol
Definition and Purpose
Procedures to protect water bodies from debris and wastes associated with structure demolition or removal over or adjacent receiving waters.
Appropriate Applications
■ Full bridge demolition and removal projects.
■ Partial bridge removal (e.g., barrier rail, edge of deck) associated with bridge widening projects. ■ Projects that involve concrete channel removal.
■ Any other project with structure removal that could potentially affect water quality.
Limitations
■ Specific requirements may be included in the contract documents and permit documents associated with regulatory agencies such as the Regional Water Quality Control Board, U.S.
Army Corps of Engineers, and California Department of Fish and Wildlife.
Standards and Specifications
General Requirements
■ A plan summarizing material containment, collection, and handling may be required to be submitted and fully implemented with the SWPPP.
Structure Demolition/Removal Over or
Adjacent to Water NS-15
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Structure Demolition/Removal Over or Adjacent to Water NS-15 March 2024 2 of 3
■ Do not allow demolished material to enter storm drain systems and receiving waters. Use covers and platforms authorized by the Resident Engineer (RE) to collect debris. ■ Collect and contain all demolished material within the containment system, including process water and visible dust produced during demolition and cleaning operations daily. Handle debris according to Standard Specifications Section 13-4.03D.
■ Implement in combination with NS-13, “Material and Equipment Use Over Water” and WM-04 “Spill Prevention and Control” for handling of materials and equipment. ■ Routinely sweep and vacuum work area to remove excess dust and debris in accordance with SC-07, “Street Sweeping.”
■ Use inlet protection in accordance with SC-10, “Temporary Drainage Inlet Protection” to protect storm drain inlets.
■ Refer to NS-5, “Clear Water Diversion” to direct water away from work areas. ■ Stockpile accumulated debris and waste generated during demolition away from drainage inlets and receiving waters and in accordance with WM-3, “Stockpile Management.” ■ For structures containing hazardous materials (e.g., lead paint or asbestos) refer to WM-6, “Hazardous Waste Management.” For demolition work involving soil excavation around leadpainted structures, refer to WM 7, “Contaminated Soil Management.” ■ Discharges to drainage inlets and receiving waters shall be reported to the RE immediately upon discovery. A written discharge notification must follow. ■ Keep adequate spill kit material on site in accordance with a spill response plan, if applicable.
Ensure that staff are trained regarding the deployment of the spill response plan. ■ Ensure safe passage of wildlife; refer to Standard Specifications Section 83-3 – “Concrete Barriers.”
Other Considerations
■ Use attachments on construction equipment, such as backhoes and debris baskets, or barges to catch debris from demolition operations. Use plastic bibs to prevent hydraulic fuel leaks. ■ Install perimeter controls and secondary containment to prevent leaks and spills from entering receiving waters. Perimeter controls and secondary containment may include sealed plywood and/or plastic sheeting, plastic liners and/or tarps, netting, silt fences, drip pans, containment booms and berms, and absorbent material.
Maintenance and Inspection
■ Contractor must inspect demolition areas and containment systems over or adjacent receiving waters daily when operations are ongoing.
■ Any debris-catching devices and containment systems shall be emptied daily. Collected debris shall be removed and stored away from the drainage inlets and receiving waters and protected from run-on and runoff.
■ Inspect demolition and containment systems over or adjacent to waterbody for leaks and spills at least weekly (some operations require daily inspection), prior to a forecasted storm event, daily during extended rain events, and post qualifying precipitation events.
Structure Demolition/Removal Over or
Adjacent to Water NS-15
Caltrans Stormwater Quality Handbooks Section 7
Construction Site BMP Manual Structure Demolition/Removal Over or Adjacent to Water NS-15 March 2024 3 of 3
■ Inspection and maintenance of these areas must be properly documented and ensure no potential for discharges from these areas as part of the non-visible monitoring requirements.
SWPPP or WPCP
Structure Demolition/Removal Over or Adjacent to Water must be discussed in Section 600.2.1 of the SWPPP or Section 30.3.1 of the WPCP.
8-1
Section 8
Waste Management and Materials
Pollution Control BMPs
8.1 Waste Management and Materials Pollution Control
Like non-stormwater management, waste management and materials pollution control BMPs are source control BMPs that prevent pollution by limiting or reducing potential pollutants at their source before they come in contact with stormwater. These BMPs also involve day-to-day operations of the construction site and are under the control of the Contractor, and are additional “good housekeeping practices” that involve keeping a clean, orderly construction site. These controls must be implemented for all applicable activities, material usage, and site conditions.
8.1.1 Waste Management BMPs
Waste management consists of implementing procedural and structural BMPs for handling, storing, and disposing of wastes generated by a construction project to prevent the release of waste materials into stormwater discharges.
8.1.2 Materials Pollution Control BMPs
Materials pollution control (also called materials handling) consists of implementing procedural and structural BMPs for handling, storing, and using construction materials to prevent the release of those materials into stormwater discharges. The objective is to reduce the opportunity for rainfall to come in contact with these materials.
Table 8-1 lists the waste management and materials pollution control BMPs.
Table 8-1. Waste Management and Materials Pollution Control BMPs ID BMP Name
WM-1 Material Delivery and Storage
WM-2 Material Management
WM-3 Stockpile Management
WM-4 Spill Prevention and Control
WM-5 Solid Waste Management
WM-6 Hazardous Waste Management
WM-7 Contaminated Soil Management
WM-8 Concrete Residuals and Washout Wastes
WM-9 Sanitary and Septic Waste Management
WM-10 Liquid Waste Management
The remainder of this section shows the working details for each of the waste management and materials pollution control BMPs.
WM-1
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Material Delivery and Storage WM-1 March 2024 1 of 3
Material Delivery and Storage
MS
Standard Symbol
Definition and Purpose
Procedures and practices for the proper handling and storage of materials in a manner that minimizes or eliminates the discharge of these materials to the storm drain system or to receiving waters.
Appropriate Applications
These procedures are implemented at all construction sites with delivery and storage of the following:
■ Hazardous chemicals such as:
− acids
− lime
− glues
− adhesives
− paints
− solvents
− curing compounds
■ Soil stabilizers and binders
■ Fertilizers
■ Detergents
■ Plaster
Material Delivery and Storage WM-1
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Material Delivery and Storage WM-1 March 2024 2 of 3
■ Polymers
■ Petroleum products such as fuel, oil, and grease
■ Asphalt and concrete components
■ Pesticides and herbicides
■ Other materials that may be detrimental if released to the environment.
Limitations
■ Space limitation may preclude indoor storage.
■ Storage sheds must meet building and fire code requirements and be leak free.
Standards and Specifications
General
■ Train employees and subcontractors on the proper material delivery and storage practices. ■ Temporary storage area shall be located away from vehicular traffic. ■ Safety Data Sheets shall be supplied to the Resident Engineer for all materials stored. This can be done at any time but at least 5 days prior to material being used or stored on site. ■ Must comply with Caltrans Standard Specifications Section 13-4, “Job Site Management,” and 14-11, “Hazardous Waste and Contamination.”
Material Storage Areas and Practices
■ Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or 302 shall be stored in approved containers and drums and shall be placed in temporary containment facilities for proper storage.
■ Each temporary containment facility shall have a permanent cover and side wind protection, or be covered during non-working days and whenever a storm event is forecasted. ■ A temporary containment facility shall provide for a spill containment volume able to contain precipitation from a 24-hour, 25-year storm event, plus the greater of 10 percent of the aggregate volume of all containers or 100 percent of the capacity of the largest container within its boundary.
■ A temporary containment facility shall be impervious to the materials stored therein for a minimum contact time of 72 hours.
■ A temporary containment facility shall be maintained free of accumulated rainwater and spills. In the event of spills or leaks, accumulated rainwater and spills shall be collected and placed into drums. These liquids shall be handled as a hazardous waste unless testing determines them to be non-hazardous. All collected liquids or non-hazardous liquids shall be sent to an approved disposal site.
■ Sufficient separation shall be provided between stored containers to allow for spill cleanup and emergency response access.
Material Delivery and Storage WM-1
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Material Delivery and Storage WM-1 March 2024 3 of 3
■ Incompatible materials, such as chlorine and ammonia, shall not be stored in the same temporary containment facility.
■ Materials shall be stored in their original containers. The original product labels shall be maintained in place in a legible condition. Damaged or otherwise illegible labels shall be replaced immediately.
■ Bagged and boxed materials shall be stored on pallets and shall not be allowed to accumulate on the ground. To provide protection from wind and rain, bagged and boxed materials shall be covered during non-working days and prior to rain events. ■ Stockpiles shall be protected in accordance with WM-3, “Stockpile Management.” ■ Have proper storage instructions posted at all times in an open and conspicuous location and include it as an informal training component of the tailgates and ongoing WPC training. ■ Do not store hazardous chemicals, drums, or bagged materials directly on the ground. Place these items on a pallet, under cover, and in secondary containment. ■ Keep ample supply of appropriate spill clean-up material near storage areas. ■ Also, see WM-6, “Hazardous Waste Management” for storing of hazardous materials.
Material Delivery Practices
■ Keep an accurate, up-to-date inventory of material delivered and stored on site. ■ Employees trained in emergency spill clean-up procedures shall be present when dangerous materials or liquid chemicals are unloaded.
Spill Cleanup
■ Contain and clean up any spill immediately.
■ If significant residual materials remain on the ground after construction is complete, properly remove and dispose any hazardous materials or contaminated soil.
Maintenance and Inspection
■ Storage areas shall be kept clean, well organized, and equipped with ample clean-up supplies as appropriate for the materials being stored.
■ Perimeter controls, containment structures, covers, and liners shall be repaired or replaced as needed to maintain proper function.
■ Inspect storage areas before, during, and after rainfall events, and at least weekly during other times. Collect and place into drums any spills or accumulated rainwater and dispose properly. ■ Material delivery and storage areas must be shown on the WPCDs and reflect current site conditions.
SWPPP or WPCP
Material delivery and storage must be discussed in Section 600.2.2 of the SWPPP or Section
30.3.2 of the WPCP.
WM-2
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Material Management WM-2
March 2024 1 of 3
Material Management
MU
Standard Symbol
Definition and Purpose
These are procedures and practices for use of construction materials in a manner that minimizes or eliminates the discharge of these materials to the storm drain system or to receiving waters.
Appropriate Applications
This BMP applies to all construction projects. These procedures apply when the following materials are used or prepared on site:
■ Hazardous chemicals such as:
− acids
− lime
− glues
− adhesives
− paints
− solvents
− curing compounds
■ Soil stabilizers and binders
■ Fertilizers
■ Detergents
■ Plaster
■ Petroleum products such as fuel, oil, and grease
Material Management WM-2
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Material Management WM-2
March 2024 2 of 3
■ Asphalt and concrete components
■ Pesticides and herbicides
■ Other materials that may be detrimental if released to the environment Limitations
■ Safer alternative building and construction products may not be available or suitable in every instance.
Standards and Specifications
■ Safety Data Sheets shall be supplied to the Resident Engineer for all materials. ■ Latex paint and paint cans, used brushes, rags, absorbent materials, and drop cloths, when thoroughly dry, and are no longer hazardous and may be disposed with other construction debris.
■ Do not remove the original product label as it contains important safety and disposal information. Use the entire product before disposing the container. ■ Mix paint indoors or in a containment area. Never clean paint brushes or rinse paint containers into a street, gutter, or storm drain, or near a water body. Dispose any paint thinners, residue, and sludge(s) that cannot be recycled as hazardous waste. ■ For water based paint, clean brushes to the extent practical and rinse to a drain leading to a sanitary sewer where permitted, or into a concrete washout pit. For oil-based paints, clean brushes to the extent practical and filter and reuse thinners and solvents. ■ Use recycled and less-hazardous products when practical. Recycle residual paints, solvents, non-treated lumber, and other materials.
■ Use materials only where and when needed to complete the construction activity. Use safer alternative materials as much as possible.
■ Do not over-apply fertilizers and pesticides. Prepare only the amount needed. Strictly follow the recommended usage instructions.
■ Application of herbicides and pesticides shall be performed by a licensed applicator. Document the location, chemicals applied, and applicant’s name and qualifications. ■ Contractors are required to complete the “Report of Chemical Spray Forms” when spraying herbicides and pesticides.
■ Keep an ample supply of spill clean-up material near use areas. Train employees in spill clean up procedures.
■ Avoid exposing applied materials to rainfall and runoff unless sufficient time has been allowed for them to dry.
Material Management WM-2
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Material Management WM-2
March 2024 3 of 3
Maintenance and Inspections
■ Inspect storage areas before, during, and after rainfall events, and at least weekly during other times. Collect and place into drums any spills or accumulated rainwater and dispose properly. ■ Spot-check employees and subcontractors throughout the job; include appropriate practices as part of the informal tailgate training.
SWPPP or WPCP
Material Management must be discussed in Section 600.2.2 of the SWPPP or Section 30.3.2 of the WPCP. Material storage areas should be included in the WPCDs.
WM-3
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Stockpile Management WM-3
March 2024 1 of 3
Stockpile Management
Standard Symbol
Definition and Purpose
Stockpile management procedures and practices are designed to reduce or eliminate air and stormwater pollution from stockpiles of soil, and paving materials such as portland cement concrete (PCC) rubble, asphalt concrete (AC), AC rubble, aggregate base, aggregate subbase or pre-mixed aggregate, asphalt binder (so called “cold mix” asphalt) and pressure-treated wood.
Appropriate Applications
Implemented in all projects that stockpile soil and other materials.
Limitations
Use of plastic cover might be restricted depending on the location of the site and regulatory permits.
Standards and Specifications
Stockpiles must comply with Standard Specifications Section 13-4.03C(3) – “Stockpile Management.”
■ Stockpile protection is a year-round requirement.
■ Locate stockpiles a minimum of 50 feet from concentrated flows of storm water, drainage courses, and inlets.
■ Use run-on and runoff BMPs to ensure stockpile materials are protected and do not have the potential to discharge material.
■ Implement wind erosion control practices as appropriate on all stockpiled material. For specific information, see WE-1, “Wind Erosion Control.”
Stockpile Management WM-3
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Stockpile Management WM-3
March 2024 2 of 3
■ Stockpiles of contaminated soil shall be managed in accordance with WM-7, “Contaminated Soil Management.”
■ Bagged materials should be placed on pallets and under cover.
Protection of Inactive Stockpiles
Inactive stockpiles of the identified materials shall be protected further as follows:
■ Soil stockpiles:
− shall be covered or protected with soil stabilization measures and a temporary perimeter sediment barrier at all times. If no longer needed, they should be removed and disposed properly.
■ Stockpiles of PCC rubble, AC, AC rubble, aggregate base, or aggregate subbase:
− shall be covered or protected with a temporary perimeter sediment barrier at all times. If no longer needed, they should be removed and disposed properly. ■ Stockpiles of “cold mix”:
− shall be placed on and covered with plastic or comparable material at all times and surround by a berm.
■ Stockpiles/Storage of pressure-treated wood with copper, chromium, and arsenic or ammoniacal, copper, zinc, and arsenate:
− shall be covered with plastic or comparable material and placed on pallets.
Protection of Active Stockpiles
Active stockpiles shall be protected further as follows:
■ All stockpiles shall be covered, stabilized, or protected with a temporary linear sediment barrier prior to the onset of precipitation.
■ Stockpiles of “cold mix” shall be placed on and covered with plastic or comparable material prior to the onset of precipitation.
■ All stockpiles should be removed from the site and disposed properly. ■ At no time should stockpiles be allowed to commingle with stormwater run-on or runoff.
Maintenance and Inspections
■ Inspect stockpile management areas before, during, and after rainfall events, and at least weekly during other times.
■ Repair and/or replace perimeter controls and covers to keep stockpile management functioning properly.
■ Stockpile management areas must be shown on the WPCDs and reflect site conditions.
SWPPP or WPCP
Stockpile management must be discussed in Section 600.2.2 of the SWPPP or Section 30.3.2 of the WPCP.
Stockpile Management WM-3
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Stockpile Management WM-3
March 2024 3 of 3
WM-4
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Spill Prevention and Control WM-4 March 2024 1 of 4
Spill Prevention and Control
Standard Symbol
Definition and Purpose
These procedures and practices are implemented to prevent and control spills in a manner that minimizes or prevents the discharge of spilled material to the drainage system or watercourses.
Appropriate Application
■ This BMP applies to all construction projects. Spill control procedures are implemented any time chemicals and/or hazardous substances are stored. Substances may include, but are not limited to:
− Soil stabilizers/binders
− Dust palliatives
− Herbicides
− Growth inhibitors
− Fertilizers
− Deicing/anti-icing chemicals
− Fuels
− Lubricant
− Other petroleum distillates
■ To the extent that the work can be accomplished safely, spills of oil; petroleum products; substances listed under 40 CFR parts 110, 117, and 302; and sanitary and septic wastes shall be contained and cleaned up immediately.
Spill Prevention and Control WM-4
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Spill Prevention and Control WM-4 March 2024 2 of 4
Limitations
■ This BMP only applies to spills caused by the Contractor. Other spills or discharges observed or discovered must be reported to the RE.
■ Procedures and practices presented in this BMP are general. Contractor shall identify appropriate practices for the specific materials used or stored on site and follow the appropriate Safety Data Sheet(s).
Standards and Specifications
■ Must comply with Caltrans Standard Specifications Section 13-4.03B – “Spill Prevention and Control.”
■ To the extent that it doesn’t compromise clean -activities, spills shall be covered and protected from stormwater run-on.
■ Spills shall not be buried or washed with water. Potable water has chlorine, and therefore should not be allowed to be discharged off the project site. ■ Used clean-up materials, contaminated materials, and recovered spill material that is no longer suitable for the intended purpose shall be stored and properly disposed. ■ Water used for cleaning and decontamination shall not be allowed to enter storm drains or watercourses and shall be collected and disposed in accordance with WM-10, “Liquid Waste Management.”
■ Water overflow or minor water spillage shall be contained and shall not be allowed to discharge into drainage facilities or watercourses.
■ Proper storage, clean-up, and spill reporting instruction for hazardous materials stored or used on the project site shall be posted at all times in an open, conspicuous, and accessible location. ■ Waste storage areas shall be kept clean, well-organized, and equipped with ample clean-up supplies as appropriate for the materials being stored. Perimeter controls, containment structures, covers, and liners shall be repaired or replaced as needed to maintain proper function.
Education
■ Educate employees and subcontractors on what a “significant spill” is for each material they use, and what the appropriate response is for “significant” and “insignificant” spills. ■ Educate employees and subcontractors on potential dangers to humans and the environment from spills and leaks.
■ Hold regular meetings to discuss and reinforce appropriate disposal procedures (incorporate into regular safety meetings).
■ Establish a continuing education program to indoctrinate new employees. ■ The WPC Manager shall oversee and enforce proper identification of stormwater pollution potential, spill prevention, response, control measures and spill reporting. ■ The list of reportable quantities can be found at https://www.ecfr.gov/current/title-40/chapterI/subchapter-D/part-117/subpart-A/section-117.3.
Spill Prevention and Control WM-4
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Spill Prevention and Control WM-4 March 2024 3 of 4
Clean-up and Storage Procedures
■ Minor Spills:
− Minor spills typically involve small quantities of oil, gasoline, paint, etc., which can be controlled by the first responder at the discovery of the spill. − Use absorbent materials on small spills rather than hosing down or burying the spill. − Remove the absorbent materials promptly and dispose properly. − The practice commonly followed for a minor spill is:
− Contain the spread of the spill.
− Recover spilled materials.
− Clean the area and/or properly dispose contaminated materials. ■ Semi-significant Spills:
− Semi-significant spills still can be controlled by the first responder along with the aid of other personnel such as laborers and the foreman, etc. This response may require the cessation of all other activities.
− Clean up spills immediately:
− Notify the WPC Manager immediately. The WPC Manager shall notify the RE and prepare the proper notifications as required.
− Contain spread of the spill.
− If the spill occurs on paved or impermeable surfaces, clean up using “dry” methods (absorbent materials, cat litter, and/or rags). Contain the spill by encircling with absorbent materials.
− If the spill occurs in dirt areas, immediately contain the spill. Dig up and properly dispose contaminated soil.
− If the spill occurs during rain, cover spill with tarps to prevent contaminating runoff. ■ Significant/Hazardous Spills:
− For significant or hazardous spills that cannot be controlled by personnel in the immediate vicinity, the following steps shall be taken:
− Notify the RE immediately and follow up with a written report. − Notify the local emergency response by dialing 911. In addition to 911, the Contractor will notify the proper county officials. It is the Contractor’s responsibility to have all emergency phone numbers at the construction site.
− Notify the Governor's Office of Emergency Services Warning Center, (800) 852-7550 or 1- (916) 845-8911.
− For spills of federal reportable quantities, in conformance with the requirements in 40 CFR parts 110,119, and 302, the Contractor shall notify the National Response Center at (800) 424-8802.
Spill Prevention and Control WM-4
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Spill Prevention and Control WM-4 March 2024 4 of 4
− Notification shall first be made by telephone and followed up with a written report. The reporting form is located at: https://www.caloes.ca.gov/wp-content/uploads/FireRescue/Documents/304-Written-Report-Form.pdf − The services of a spill contractor or a Haz-Mat team shall be obtained immediately.
Construction personnel shall not attempt to clean up the spill until the appropriate and qualified staff have arrived at the job site.
− Other agencies that may need to be consulted include, but are not limited to, the Fire Department, Public Works Department, the Coast Guard, Highway Patrol, the City/County Police Department, Department of Toxic Substances, California Division of Oil and Gas, Cal/OSHA, RWQCB, etc.
Maintenance and Inspection
■ Verify weekly that spill control clean-up materials are located near material storage, unloading, and use areas.
■ Update spill prevention and control plans and stock appropriate clean-up materials when changes occur in the types of chemicals used or stored onsite. ■ Improper cleanup might trigger the need for water quality or soil testing. The WPC manager should be proactive in ensuring controls are in place and adequate to contain and prevent further issues.
SWPPP or WPCP
Spill Prevention and Control must be discussed in Section 600.2.2 of the SWPPP or Section 30.3.2 of the WPCP.
WM-5
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Solid Waste Management WM-5 March 2024 1 of 3
Solid Waste Management
Standard Symbol
SWM
Definition and Purpose
Solid waste management procedures and practices are designed to minimize or eliminate the discharge of pollutants to the drainage system or to water bodies as a result of the creation, stockpiling, or removal of construction site wastes.
Appropriate Applications
Solid waste management procedures and practices are implemented on all construction projects that generate solid wastes.
Solid wastes include but are not limited to:
■ Construction wastes, including brick, mortar, timber, steel and metal scraps, sawdust, pipe and electrical cuttings, non-hazardous equipment parts, and Styrofoam and other materials used to transport and package construction materials.
■ Highway planting wastes, including vegetative material, plant containers, and packaging materials.
■ Litter, including food containers, beverage cans, coffee cups, paper bags, plastic wrappers, and smoking materials, including litter generated by the public.
Limitations
None identified.
Solid Waste Management WM-5
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Solid Waste Management WM-5 March 2024 2 of 3
Standards and Specifications
Education
■ The WPC Manager shall oversee and enforce proper solid waste procedures and practices. ■ Instruct employees and subcontractors on identification of solid waste and hazardous waste. ■ Educate employees and subcontractors on solid waste storage and disposal procedures. ■ Hold regular meetings to discuss and reinforce disposal procedures (incorporate into regular safety meetings and tailgate sessions).
■ Require that employees and subcontractors follow solid waste handling and storage procedures.
■ Prevent debris or trash from being transported by wind or runoff. ■ Prohibit littering by employees, subcontractors, and visitors. ■ Wherever possible, minimize production of solid waste materials. ■ Must comply with Standard Specifications Section 14-10 – “Solid Waste Disposal and Recycling” and 13-4 – “Job Site .”Management.
Collection, Storage, and Disposal
■ Dumpsters of sufficient size and number shall be provided to contain the solid waste generated by the project, and be properly serviced. Must ensure that containers are watertight and have a cover.
■ Littering on the project site shall be prohibited.
■ To prevent clogging of the storm drainage system, litter and debris removal from drainage grates, trash racks, and ditch lines shall be a priority. ■ Trash receptacles shall be provided in the Contractor’s yard, field trailer areas, and at locations where workers congregate for lunch and break periods.
■ Construction debris and litter from work areas within the construction limits of the project site shall be collected and placed in watertight dumpsters at least weekly regardless of whether the litter was generated by the Contractor, the public, or others. Collected litter and debris shall not be placed in or next to drain inlets, storm water drainage systems, or watercourses. ■ Full dumpsters shall be removed from the project site and the contents shall be disposed outside the highway right-of-way in conformance with the provisions in Standard Specifications Section 14-10 – “Solid Waste Disposal and Recycling.”
■ Litter stored in collection areas and containers shall be handled and disposed by trash hauling contractors.
■ Stormwater run-on shall be prevented from contacting stored solid waste by berms, dikes, or other temporary diversion structures, or through the use of measures to elevate waste from site surfaces.
■ Solid waste storage areas shall be located at least 50 feet from drainage facilities and watercourses and shall not be located in areas prone to flooding or ponding.
Solid Waste Management WM-5
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Solid Waste Management WM-5 March 2024 3 of 3
■ Except during fair weather, construction and highway planting waste not stored in watertight dumpsters shall be securely covered from wind and rain by covering the waste with tarps or plastic sheeting.
■ Dumpster wash on the project site is not allowed.
■ Notify trash hauling contractors that only watertight dumpsters are acceptable for use on site. ■ Plan for additional containers during the demolition phase of construction. ■ Plan for more frequent pickup during the demolition phase of construction. ■ Construction waste shall be stored in a designated area and shown in the WPCDs. ■ Segregate potentially hazardous waste from non-hazardous construction site waste. ■ Keep the site clean of litter debris.
■ Make sure that toxic liquid wastes (e.g., used oils, solvents, and paints) and chemicals (e.g., acids, pesticides, additives, curing compounds) are not disposed in dumpsters designated for construction debris.
■ Dispose non-hazardous waste in accordance with Standard Specifications Section 14-10 – “Solid Waste Disposal and Recycling.”
■ For disposal of hazardous waste, see BMP WM-6, “Hazardous Waste Management.” Have hazardous waste hauled to an appropriate disposal and/or recycling facility. ■ Salvage or recycle useful vegetation debris, packaging, and/or surplus building materials when practical. For example, trees and shrubs from land clearing can be converted into wood chips, then used as mulch on graded areas. Wood pallets, cardboard boxes, and construction scraps can also be recycled.
Maintenance and Inspection
■ The WPC Manager shall monitor on-site solid waste storage and disposal procedures. ■ Specific locations for solid waste storage or containment must be shown in the WPCDs and must be inspected and maintained regularly.
■ Cover waste disposal containers at the end of every business day and during a precipitation event for SWPPP projects.
SWPPP or WPCP
■ Solid Waste Management must be discussed in Section 600.2.2 of the SWPPP or Section
30.3.2 of the WPCP.
WM-6
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Hazardous Waste Management WM-6 March 2024 1 of 4
Hazardous Waste Management
Standard Symbol
Definition and Purpose
These are procedures and practices to minimize or eliminate the discharge of pollutants from construction site hazardous waste to the storm drain systems or to watercourses.
Appropriate Applications
■ This BMP applies to all construction projects.
■ Hazardous waste management practices are implemented on construction projects that generate waste from the use of:
− Petroleum products
− Asphalt products
− Concrete curing compounds
− Pesticides
− Palliatives
− Acids
− Paints
− Stains
− Solvents
− Septic wastes
− Wood preservatives
Hazardous Waste Management WM-6
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Hazardous Waste Management WM-6 March 2024 2 of 4
− Roofing tar
− Any materials deemed a hazardous waste in California, Title 22 Division 4.5, or listed in 40 CFR Parts 110, 117, 261, or 302.
Limitations
■ Nothing in this BMP relieves the Contractor from responsibility for compliance with federal, state, and local laws regarding storage, handling, transportation, and disposal of hazardous wastes.
■ This BMP does not cover aerially deposited lead (ADL) soils. For ADL soils, refer to WM-7, “Contaminated Soil Management” and the project special provisions.
Standards and Specifications
Education
■ Educate employees and subcontractors on hazardous waste storage and disposal procedures. ■ Educate employees and subcontractors on potential dangers to humans and the environment from hazardous wastes.
■ Instruct employees and subcontractors on safety procedures for common construction site hazardous wastes.
■ Instruct employees and subcontractors in identification of hazardous and solid waste. ■ Hold regular meetings to discuss and reinforce hazardous waste management procedures (incorporate into regular safety meetings and tailgate sessions). ■ The WPC Manager must oversee and enforce proper hazardous waste management procedures and practices.
■ Make sure that hazardous waste is collected, removed, and disposed only at authorized disposal areas.
Storage Procedures
■ Wastes shall be stored in sealed containers constructed of a suitable material and shall be labeled as required by Title 22 CCR, Division 4.5 and 49 CFR Parts 172,173, 177 and 178, 179. ■ All hazardous waste shall be stored, transported, and disposed as required in Title 22 CCR, Division 4.5 and 49 CFR 261-263.
■ Waste containers shall be stored in temporary containment facilities that shall comply with the following requirements:
− Temporary containment facility shall provide for a spill containment volume able to contain precipitation from a 24-hour, 25-year storm event, plus the greater of 10 percent of the aggregate volume of all containers or 100 percent of the capacity of the largest tank within its boundary.
− Temporary containment facility shall be impervious to the materials stored there for a minimum contact time of 72 hours.
Hazardous Waste Management WM-6
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Hazardous Waste Management WM-6 March 2024 3 of 4
− Temporary containment facilities shall be maintained free of accumulated rainwater and spills. In the event of spills or leaks, accumulated rainwater and spills shall be placed into drums after each rainfall. These liquids shall be handled as a hazardous waste unless testing determines them to be non-hazardous. Non-hazardous liquids shall be sent to an approved disposal site.
− Sufficient separation shall be provided between stored containers to allow for spill cleanup and emergency response access.
− Incompatible materials, such as chlorine and ammonia, shall not be stored in the same temporary containment facility.
− Temporary containment facilities shall be covered during non-working days and prior to rain events. Covered facilities may include use of plastic tarps for small facilities or constructed roofs with overhangs. A storage facility having a solid cover and sides is preferred to a temporary tarp. Storage facilities shall be equipped with adequate ventilation. ■ Drums shall not be overfilled and wastes shall not be mixed. ■ Unless watertight, containers of dry waste shall be stored on pallets. ■ Paint brushes and equipment for water and oil-based paints shall be cleaned within a contained area and shall not be allowed to contaminate site soils, watercourses, or drainage systems.
Waste paints, thinners, solvents, residues, and sludges that cannot be recycled or reused shall be disposed as hazardous waste. When thoroughly dry, latex paint and paint cans, used brushes, rags, absorbent materials, and drop cloths shall be disposed as solid waste. ■ Ensure that adequate hazardous waste storage volume is available. ■ Ensure that hazardous waste collection containers are conveniently located. ■ To prevent accidental spills, designate hazardous waste storage areas on site away from storm drains or watercourses and away from moving vehicles and equipment. ■ Minimize production or generation of hazardous materials and hazardous waste on the job site. ■ Use containment berms in fueling and maintenance areas and where the potential for spills is high.
■ Segregate potentially hazardous waste from non-hazardous construction site debris. ■ Keep liquid or semi-liquid hazardous waste in appropriate containers (closed drums or similar) and under cover.
■ Clearly label all hazardous waste containers with the waste being stored and the date of accumulation.
■ Place hazardous waste containers in secondary containment. ■ Do not allow potentially hazardous waste materials to accumulate on the ground. ■ Do not mix wastes.
Hazardous Waste Management WM-6
Caltrans Stormwater Quality Handbooks Section 6
Construction Site BMP Manual Hazardous Waste Management WM-6 March 2024 4 of 4
Disposal Procedures
■ Waste shall be disposed outside the highway right of way within 90 days of being generated, or as directed by the Resident Engineer. In no case shall hazardous waste storage exceed requirements in Title 22 CCR, Section 66262.34.
■ Waste shall be disposed by a licensed hazardous waste transporter at an authorized and licensed disposal facility or recycling facility using properly completed Uniform Hazardous Waste Manifest forms.
■ An Environmental Laboratory Accreditation Program (ELAP)-accredited laboratory shall sample waste and analyze it to determine the appropriate disposal facility. ■ Make sure that toxic liquid wastes (e.g., used oils, solvents, paints) and chemicals (e.g., acids, pesticides, additives, curing compounds) are not disposed in dumpsters designated for solid waste construction debris.
■ Properly dispose of rainwater that may have mixed with hazardous waste in secondary containment.
■ Recycle any useful material such as used oil or water-based paint when practical. ■ Attention is directed to “Hazardous Material,” “Contaminated Material,” and “Aerially Deposited Lead” of the Contract documents regarding the handling and disposal of hazardous materials.
Maintenance and Inspection
■ The WPC Manager or QSP shall monitor on-site hazardous waste storage and disposal procedures.
■ Waste storage areas shall be kept clean, well-organized, and equipped with ample clean up supplies as appropriate for the materials being stored. ■ Storage areas shall be inspected in conformance with the provisions in the Contract Documents. At a minimum, storage areas must be inspected before, daily during extended storm events, after every storm event, and weekly year-round. Perimeter controls, containment structures, covers, and liners shall be repaired or replaced as needed to maintain proper function.
■ Hazardous spills shall be cleaned up and reported in conformance with the applicable Safety Data Sheet and the instructions posted at the project site. ■ The National Response Center, at (800) 424-8802, shall be notified of spills of federal reportable quantities in conformance with the requirements in 40 CFR parts 110, 117, and 302. ■ Copies of the hazardous waste manifests shall be provided.
SWPPP or WPCP
■ Hazardous Waste Management must be discussed in Section 600.2.2 of the SWPPP or Section
30.3.2 of the WPCP.
WM-7
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Contaminated Soil Management WM-7 March 2024 1 of 4
Contaminated Soil Management
Standard Symbol
Definition and Purpose
These are procedures and practices to minimize or eliminate the discharges of pollutants to the drainage system or to receiving waters from contaminated soil.
Appropriate Applications
■ Contaminated soil management is implemented on construction projects where soil contamination may have occurred due to spills, illicit discharges, or leaks from underground storage tanks.
■ It may also apply to highway widening projects in older areas where median and shoulder soils may have been contaminated by aerially deposited lead (ADL).
Limitations
■ The procedures and practices presented in this BMP are general. The Contractor shall identify appropriate practices and procedures consistent with the plans and specifications for the specific contaminants known to exist or discovered on site.
Standards and Specifications
Identifying Contaminated Areas
■ Contaminated soils are often identified during project planning and development with known locations identified in the plans and specifications. The Contractor shall review applicable reports and examine applicable call-outs in the plans and specifications.
Contaminated Soil Management WM-7
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Contaminated Soil Management WM-7 March 2024 2 of 4
■ The Contractor may discover contaminated soils not identified in the plans and specifications by observing spills and leaks, discoloration, odors or abandoned underground tanks or pipes. ■ Spills and leaks caused by the Contractor are the Contractor’s responsibility for removal, testing, and disposal.
■ If unanticipated asbestos or hazardous substances are discovered that were not released by the Contractor, the Contractor shall stop work in that area and immediately notify the Resident Engineer (RE). The Contractor shall not resume work in the area until directed to do so.
Education
■ Prior to performing any excavation work at the locations containing material classified as hazardous, employees and subcontractors shall complete a safety training program that meets 29 CFR 1910.120 and 8 CCR 5192, covering the potential hazards as identified. ■ Educate employees and subcontractors in identification of contaminated soil and on contaminated soil handling, containment, and disposal procedures. ■ Hold regular meetings to discuss and reinforce contaminated soil handling, containment, and disposal procedures (incorporate into regular safety meetings and tailgates).
Handling Procedures for Material with Aerially Deposited Lead (ADL) ■ Materials from areas designated as containing ADL may, if allowed by the contract special provisions, be excavated, transported, and used in the construction of embankments and/or backfill.
■ Must comply with Standard Specifications Section 14-11 – “Hazardous Waste and Contamination.”
■ Must comply with the DTSC ADL agreement for specific requirements regarding handling, stockpiling, and hauling of material.
■ Excavation, transportation, and placement operations shall result in no visible dust. ■ Use caution to prevent spillage of lead-containing material during transport. ■ Monitor the air quality during excavation of soils contaminated with lead.
Handling Procedures for Contaminated Soils
■ Contaminated soil shall be disposed properly in compliance with the specifications and all applicable regulations in Title 22, CCR, Division 4.5 and Standard Specifications Section 14-11. ■ If required by the specifications, test contaminated soils at a SWRCB Environmental Laboratory Accreditation Program (ELAP) certified laboratory.
■ If the soil is contaminated, work with the local regulatory agencies to develop options for treatment and/or disposal.
■ Avoid temporary stockpiling of contaminated soils or hazardous material. ■ If temporary stockpiling is allowed by the specifications, place plastic sheeting or tarps underneath material and cover the stockpile with plastic sheeting or tarps, if required by the specifications.
■ Install a berm around the stockpile to prevent run-on or runoff from leaving the area.
Contaminated Soil Management WM-7
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Contaminated Soil Management WM-7 March 2024 3 of 4
■ Do not stockpile in or near storm drains or receiving water. ■ Install berms or run-on controls to prevent stormwater from commingling with contaminated areas.
■ Contaminated material and hazardous material on exteriors of transport vehicles shall be removed and placed either into the current transport vehicle or the excavation prior to the vehicle leaving the exclusion zone.
■ Monitor the air quality during excavation operations if required. ■ Procure all permits and licenses, pay all charges and fees, and give all notices necessary and incident to the due and lawful prosecution of the work, including registration for transporting vehicles carrying the contaminated material and the hazardous material. ■ Collect water from decontamination procedures and treat and/or dispose it at an appropriate disposal site.
■ Collect non reusable protective equipment once used by any personnel, and dispose at an appropriate disposal site.
■ Install temporary security fence to surround and secure the exclusion zone. Remove fencing when no longer needed.
■ Excavation, transport, and disposal of contaminated material and hazardous material shall be in accordance with the rules and regulations of the following agencies (the specifications of these agencies supersede the procedures outlined in this BMP):
− United States Department of Transportation (USDOT).
− United States Environmental Protection Agency (USEPA). − California Environmental Protection Agency (CAL-EPA). − California Division of Occupation Safety and Health Administration (CAL-OSHA). − Local regulatory agencies.
Procedures for Underground Storage Tank Removals
■ If an unknown underground storage tank is discovered, the Contractor shall stop work in that area and immediately notify the RE. The Contractor shall not resume work in the area until directed to do so.
■ If tank removal operations are required by the contract, follow the contract requirements for obtaining permits and approval from the federal, state, and local agencies, which have jurisdiction over such work.
■ If tank removal operations are required by the contract, the underground storage tank, any liquid and/or sludge found within the tank, and all contaminated substances and hazardous substances removed during the tank removal shall be transported to disposal facilities as required by the contract specifications.
Contaminated Soil Management WM-7
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Contaminated Soil Management WM-7 March 2024 4 of 4
Water Control
■ Take all necessary precautions and preventive measures to prevent the flow of water, including ground water, from mixing with contaminated or hazardous materials or entering contaminated soil excavations. Such preventative measures may consist of, but are not limited to, berms, cofferdams, grout curtains, freeze walls, seal course concrete, or any combination thereof. ■ If water does enter an excavation and becomes contaminated, such water, when necessary to proceed with the work, shall be dewatered consistent with NS-2, “Dewatering” and the Caltrans Field Guide to Construction Site Dewatering Manual, and in compliance with the specifications.
Maintenance and Inspection
■ The WPC Manager shall monitor on-site contaminated soil storage and disposal procedures. ■ Monitor the air quality during excavation operations if required ■ Manage contaminated soils and hazardous substances/waste under the appropriate federal, state, and local requirements.
■ Inspect stockpiles, hazardous waste receptacles, and storage areas regularly.
SWPPP or WPCP
Contaminated Soil Management must be discussed in Section 600.2.2 of the SWPPP or Section
30.3.2 of the WPCP.
WM-8
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Concrete Waste Management WM-8 March 2024 1 of 5
Concrete Waste Management
Standard Symbol
Definition and Purpose
These are procedures and practices that are designed to minimize or eliminate the discharge of concrete waste materials to the storm drain systems or watercourses.
Appropriate Applications
■ Where concrete is used as a construction material or where concrete dust and debris result from demolition activities.
■ Where slurries containing portland cement concrete (PCC) or asphalt concrete (AC) are generated, such as from saw cutting, coring, grinding, grooving, and hydro-concrete demolition. ■ Where concrete trucks and other concrete-coated equipment are washed on site, when approved by the Resident Engineer (RE). See also NS-8, “Vehicle and Equipment Cleaning.” ■ Where mortar-mixing stations exist.
Limitations
■ None identified.
Standards and Specifications
Education
■ Educate employees, subcontractors, and suppliers on the concrete waste management techniques described herein.
■ The WPC Manager shall oversee and enforce concrete waste management procedures.
Concrete Waste Management WM-8
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Concrete Waste Management WM-8 March 2024 2 of 5
Concrete Demolition Wastes
■ Stockpile concrete demolition wastes in accordance with BMP WM-3, “Stockpile Management.” ■ Disposal of hardened PCC and AC waste shall be in conformance with Standard Specifications Section 14-10 – “Solid Waste Disposal and Recycling.”
Concrete Slurry Waste Management and Disposal
■ PCC and AC waste shall not be allowed to enter storm drainage systems or watercourses. ■ A sign shall be installed adjacent to each temporary concrete washout facility to inform concrete equipment operators to use the proper facilities.
■ The WPC manager must ensure that on-site concrete working tasks are being monitored, such as saw cutting, coring, grinding, and grooving to ensure proper methods are implemented. ■ Residue from saw cutting, coring, and grinding operations shall be picked up by means of a vacuum device. Residue shall not be allowed to flow across the pavement and shall not be left on the pavement surface. See also NS-3, “Paving, Sealing, Saw Cutting, Grooving, and Grinding Operations.”
■ Vacuumed slurry residue shall be disposed in accordance with WM-5, “Solid Waste Management” and Standard Specifications Section 13-4.03D – “Waste Management.” Slurry residue shall be temporarily stored in a facility as described below in “On-site Temporary Concrete Washout Facility, Concrete Transit Truck Washout Procedures,” or within an impermeable containment vessel or bin.
■ Collect and dispose all residues from grooving and grinding operations in accordance with Standard Specifications Section 14-10, – “Solid Waste Disposal and Recycling” and 14-11, “Hazardous Waste and Contamination.”
On-site Temporary Concrete Washout Facility, Concrete Transit Truck Washout Procedures
■ Temporary concrete washout facilities shall be located a minimum of 50 feet from storm drain inlets, open drainage facilities, and watercourses unless determined infeasible by the RE. Each facility shall be located away from construction traffic or access areas to prevent disturbance or tracking.
■ A sign shall be installed adjacent to each washout facility to inform concrete equipment operators to use the proper facilities. The sign shall be installed as shown on the plans and in conformance with the provisions in Standard Specifications Section 56 2 – “Overhead Sign Structures.”
■ Temporary concrete washout facilities shall be constructed above grade or below grade at the option of the Contractor. Temporary concrete washout facilities shall be constructed and maintained in sufficient quantity and size to contain all liquid and concrete waste generated by washout operations.
■ Temporary washout facilities shall have a temporary pit or bermed areas of sufficient volume to completely contain all liquid and waste concrete materials generated during washout procedures.
■ Perform washout of concrete mixers, delivery trucks, and other delivery systems in designated areas only.
Concrete Waste Management WM-8
Caltrans Stormwater Quality Handbooks Section 8
Construction Site BMP Manual Concrete Waste Management WM-8 March 2024 3 of 5
■ Wash concrete only from mixer chutes into approved concrete washout facility. Washout may be collected in an impermeable bag or other impermeable containment devices for disposal. ■ Pump excess concrete in concrete pump bin back into concrete mixer truck. ■ Concrete washout from concrete pumper bins can be washed into concrete pumper trucks and discharged into designated washout area, or properly disposed offsite. ■ Once concrete wastes are washed into the designated area and allowed to harden, the concrete shall be broken up, removed, and disposed in conformance with the provisions in Standard Specifications Section 13-4.03D(3), “) Concrete Waste;” 13-9, “ Temporary Concrete Washouts;” 15-1.03B, “Removing Concrete;” and 14-10, “Solid Waste Disposal & Recycling.” Temporary Concrete Washout Facility Type “Above Grade”
■ Temporary concrete washout facility type “Above Grade” shall be constructed as shown on