California s New Construction General Permit Thursday, October 01, 2009
Workshop Agenda 1:00 1:05 Introductions 1:05 1:20 FMFCD Storm Drain System 1:20 2:00 Construction General Permit Coverage» Status of Existing Projects» Transition to New Permit» Permit Registration Documents» Risk Level Determination» SWPPP Developers & Practitioners 2:00 2:45 Mandatory Site Management Practices 2:45-3:00 Break 3:00 3:30 Quantitative Performance Standards 3:30 3:40 Rain Event Action Plans 3:40 4:10 Construction Project Phasing 4:10 4:20 Reporting Requirements 4:20 4:25 Terminating Permit Coverage 4:25 4:30 Closing Comments
State Water Resources Control Board Web Site Construction General Permit Documents http://www.swrcb.ca.gov/water_issues/programs/stormwater/constpermits.shtml
Why is Stormwater Regulated? The Increased Volume of Runoff Generated by Increased Impervious (developed) Areas Damages Streams and Rivers and also Decreases the Amount of Water that Soaks into the Ground Carries or Transports Pollutants into Streams, Rivers and Oceans (Contributes to pollutant load in Receiving Waters)
40% evapotranspiration 38% evapotranspiration 10% runoff 20% runoff 25% shallow infiltration Natural Ground Cover 25% deep infiltration 21% shallow infiltration 10%-20% Impervious Surface 21% deep infiltration 35% evapotranspiration 30% evapotranspiration 30% runoff 55% runoff 20% shallow infiltration 35%-50% Impervious Surface 15% deep infiltration 10% shallow infiltration 75%-100% Impervious Surface 5% deep infiltration
Clean Water Act Prohibits certain discharges of stormwater containing pollutants except in compliance with a National Pollutant Discharge Elimination System (NPDES) permit Clean Water Act authority delegated to the State of California through the Construction General Permit (CGP)- (umbrella coverage) The CGP authorizes discharges of stormwater associated with construction activities so long as the discharger comply with all requirements, provisions and prohibitions of the CGP
Trickle Down Regulations Federal Government Clean Water Act State Water Resource Control Board Porter Cologne Act (State's Clean Water Ac) Permit Adoption and Document Submittals (SMARTS) Stormwater Multi-Application and Report Tracking System Regional Water Quality Control Board Local State Inspections and Enforcement Fresno Metropolitan Flood Control District Local Agency Oversight (Municipal Stormwater Permit) Training, Inspection and Enforcement
State Stormwater Permits CWA NPDES Permits Construction General Permit Individual Municipal Permits Fresno/Clovis Metropolitan Area Industrial General Permit
Why a new CGP? Manage pollutant loads from construction Total Maximum Daily Load (TMDL) CWA 303 (d) List Takes into account all pollutant sources within a watershed, into a receiving water and then allocates to each source an allowable amount Manage increased stormwater runoff volume from development Poor compliance with precious permit conditions Desire for numerical limits by State and Environmental Groups to measure compliance One-stop measurement
Bank scouring
After Development Volum e Before Development Time Source: Dan Cloak Consulting and Contra Costa Clean Water Program
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Pollution
Ponding Basin After Development Before Development
152 Ponding Basins 500 Miles of Pipe 200 Square Miles San Joaquin River Big Dry Drainage Direction FCR Kings River
After Development Before Development Milburn Ave Herndon Ave.
San Joaquin River Basin EK
After Development Before Development
CN Dual Use Recreation Basin Baseball Upper Floor Stormwater Storage and Recharge Lower Floor
G Dual Use Recreation Basin Baseball and Soccer Upper Floor Stormwater Storage Lower Floor Adjacent Playground No Flood Storage
URBAN STORM WATER FLOWS 90% 10% 5 % 25% 70% 55%
Risk in the 2009 CGP Considers two risk factors Sediment discharge risk Receiving water risk Risk factors combine to yield a project Risk Level Requirements increase as the project Risk Level increases Waiver for very low risk projects Existing projects have a risk determination exemption until July 1, 2011
Spreadsheet tool output
Risk Level 0 Rainfall Erosivity Waiver essentially operates as a zero risk level for small projects Small projects are those between 1 and < 5 acres Waives permit requirements for projects with an R- factor of 5 or less Based on USEPA R-factor waiver in the Phase II stormwater rule Use the EPA R-factor calculator http://cfpub.epa.gov/npdes/stormwater/lew/lewcalculat or.cfm
Permit requirements are tied to the project Risk Level Permit requirements increase moving from Risk Level 1 through Risk Level 3 REAP Compliance assessment Minimum BMPs Water quality monitoring Reporting