Stormwater and C.3 Overview

1
Stormwater and C.3Overview
Tom Dalziel, Assistant ManagerContra Costa Clean
Water Program
2
Programs C.3 web page

• www.cccleanwater.org/construction/nd.php
• The address is in the Guidebook and on the fact
  sheet
  
• Source for C.3 info and updates
• Presentation slides will be posted next week

3
Provision C.3 Topics

• Effects of New Development on water quality
• C.3 in a nutshell
• Why its called C.3
• Regulatory background
• How we got to this point
• Whats special about Contra Costas approach to
  implementing C.3
  
• BMPs and IMPs
• Objectives for todays workshop

4
Effects of New Development
Page 15
5
Runoff Before Development
6
Runoff After Development
7
Effects of increased runoff

• Increased flows and more frequent flooding leads
  to
  
• Increased streambank erosion, which leads to
• Hardening to prevent erosion, which leads to

8
Loss of Stream Functions
9
C.3 in a nutshell

• Projects subject to C.3 must
• Minimize imperviousness.
• Control potential pollutant sources.
• Treat stormwater before discharge.
• Match runoff peaks and durations to pre-project
  conditions.
  
• Maintain treatment and flow-control facilities
  in perpetuity.
  

10
Where C.3 comes from
The California Regional Water Quality Control
Board issued a
permit
requiring municipal governments to implement a
comprehensive program to control stormwater
pollutants.
Program Elements
Permit Provision C.3 requires municipalities to
mandate runoff controls as part of their
development review procedures.
Municipal Maintenance
Public Outreach
Industrial Inspections
Construction Site Inspections
Illicit Discharge Prohibition
11
Stormwater Regulatory History
12
C.3 Regulatory History
13
Contra Costas Approach

• Pro-actively assist developers to comply
• Aim for countywide consistency
• Model Stormwater Ordinance
• Stormwater Control Plan required
• Stormwater C.3 Guidebook
• Low Impact Development
• Continuous Improvement
• Updates posted on the Programs C.3 web page

14
Low Impact Development and C.3

• Low Impact Development (LID) Benefits
• Remove pollutants
• Mimic pre-development hydrology
• Program LID Strategy
• Quantify benefits so we can show compliance with
  the numeric criteria in the NPDES permit
  
• Create tools and procedures to make it easier to
  create and review LID designs

15
BMPs and IMPs
Page 19

• Best Management Practices (BMPs)
• Any procedure or facility designed to minimize
  the quantity of pollutants entering storm
  drains.
  
• Integrated Management Practices (IMPs)
• Part of a Low Impact Development approach
• Facilities that control flows and treat runoff
• Typically distributed throughout the site
• Integrated into landscape and site design
• Mimic pre-development hydrology

16
Objectives for Today

• Understand effects of hydrograph modification and
  get an introduction to stream stability analysis
  
  
• Learn the advantages and methods of implementing
  Low Impact Development
  
• Understand how C.3 fits into the development
  review process
  
• Know how flow-control facilities are analyzed
• Be able to use the Guidebook instructions and the
  Programs IMP sizing tool to design projects
  
• Discuss how you can help the Contra Costa Clean
  Water Program help you implement C.3