MRP Steering Committee MeetingApril 24, 2006

New and Redevelopment Performance Standards

Sue MaS.F. Bay Regional Water Quality Control

Board

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Workgroup Members

• Sue Ma – Water Board Staff• Jan O’Hara – Water Board Staff• Tom Dalziel – CCCWP1

• Jill Bicknell – EOA• Matt Fabry – STOPPP2

• Susan Schwartz – Friends of Five Creeks• Mondy Lariz – NCCFFF3

1 Contra Costa Clean Water Program2 San Mateo Countywide Stormwater Pollution Prevention Program3 Northern California Council Federation of Fly Fishers

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• Current Size Threshold for Treatment– All projects with > 10,000 ft2 of

new/ replaced impervious surface – Treatment BMPS sized (C.3.d)

C.3.c. New and Redevelopment Performance Standards

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C.3.c. BASMAA Option

• Maintain current size thresholds• Collect and analyze impervious

surface data over term of MRP• Evaluate future size thresholds based

on data

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C.3.c. ENGO Option 1• Dischargers can lower threshold to 5000 ft2

and/or• Adopt measures to increase infiltration and

treatment of runoff. Examples of measures: – Ordinances requiring minimum pervious

surfaces – Strong positive incentives to

• disconnect residential roof leaders• install permeable parking areas and driveways

– Banning impermeable surfacing of parking strips

– Banning direct connection of roof and yard drains

– Funds for combined controls for small projects

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C.3.c. Water Board Option• Evaluate impervious surface data to

determine if threshold should be lowered (1000 to 5000 ft2)– Implement new threshold in 3rd year of

MRP• Require impervious data collection

first 2 years of MRP– Adjust threshold up or down

• Require development of standard specifications for lot-scale treatment measures first 3 years of MRP.

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C.3.c. ENGO Option 2

Lower threshold at beginning of MRP to 500 ft2.

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C.3.c. Single Family Homes (SFH)

• Currently exempted from installing sized treatment BMPs (C.3.d.)

• Projects creating > 1 acre new/replaced impervious surface should treat runoff with source control, site designs and landscaping

• Santa Clara only: Bullet 2 threshold is 10,000 ft2

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C.3.c. (SFH) BASMAA Option

• Maintain current requirements (source control, site design, and treatment in landscaping) for projects with > 1 acre of new/replaced impervious surface

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C.3.c (SFH) ENGO Option 1

• Keep current requirements (source control, site design, and treatment in landscaping) for projects at or above threshold defined in C.3.c.

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C.3.c. (SFH) Water Board Option

• Require projects at or above threshold defined in C.3.c. to implement one or more BMPS from a list of options (to be determined and specified in the MRP)

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C.3.c. (SFH) ENGO Option 2

• Require sized treatment BMPS (C.3.d.) for projects above the threshold defined in C.3.c.

• No Discharger inspections of these treatment BMPs

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C.3.c. Comments

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C.3.e. Operation & Maintenance of Treatment Measures

• Current language requires Dischargers to:– Compile list of properties and

responsible operators– Inspect subset of prioritized treatment

measures with follow-up and correction– Require signed statements accepting

O&M responsibility and granting access permission

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C.3.e.

• Workgroup agreed treatment BMP maintenance and potential conflict with protection of endangered species should be addressed.

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C.3.e. BASMAA Option• No change from current language• Until BMP/endangered species

issue is resolved, include “safe harbor” language provision:– Dischargers are expected to work in

good faith with other agencies to obtain maintenance approvals, but if they are not granted, Dischargers will still be considered in compliance with C.3.e.

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C.3.e. Water Board Option

• Specify the following:– Minimum contents of O&M Programs– Priorities for inspection frequency

•Minimum percentage (20%) facilities inspected annually

•Minimum percentage of facilities with vault systems inspected annually

– Reporting requirements– Vector control agency coordination

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C.3.e. Comments

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C.3.f. Limitations on Increase of Peak Stormwater Runoff Rates

• Programs develop Hydromodification Management (HM) Plans for Board approval

• All HM Plans have been submitted

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C.3.f. BASMAA Option• Retain existing basic “rules”

– Threshold is 1 acre or more of new/replaced impervious surface

– No increase in runoff peaks, volumes or durations from existing site conditions

– No requirements if discharging to hardened channels or tidally influenced areas

– No requirements if no increase in impervious area

• Each Program implement its HMP• Each Program commit to effectiveness evaluation

and continuous improvement of its HMP • Revise language to reflect current status of HMPs

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C.3.f. ENGO Option 1•Retain existing basic “rules” with changes to reduce existing extreme flows:–Merge thresholds for treatment and HM–Exempt hardened channels and tidal areas if increases would not impact beneficial uses or increase flooding

–For new development, no increase in runoff peaks, volumes, or durations

–Projects redeveloping > 50% of threshold, phase in requirements to reduce runoff peaks, volumes and/or durations from existing conditions. Allow variation in local programs and exceptions based on impracticability

–Require one HMP monitoring project per Program (except Vallejo), or cooperation on 3 region-wide projects

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C.3.f. Water Board Option 1

• Retain existing basic “rules” as in BASMAA Option, Bullet 1

• Sites < X acres may size HM controls by using sizing charts or continuous simulation modeling

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C.3.f. Water Board Option 1 (cont’d)• Sites > X acres use continuous simulation

model meeting performance standards below:– 30+ years of local rainfall data; flow duration

matching for entire rainfall period of record– HM unit size and low-flow discharge will not

increase erosion potential of receiving water. Lacking other data, low-flow will be 0.1Q2.

– Post-project flow duration curve shall not deviate above pre-project curve by more than 10% over more than 10% of length of the curve

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C.3.f. Water Board Option 1 (cont’d)

• Reference each Program’s HMP and its status. Establish consistencies where needed in MRP

• Require one HM Monitoring project per Program (except Vallejo), or cooperation on 3 region-wide projects

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C.3.f. Water Board Option 2

• Same as Option 1 but add schedule to reduce flows from redevelopment projects:– If project has high risk reaches

between project and Bay, must reduce erosion potential by 50%

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C.3.f. ENGO Option 2•Projects discharging to headwaters, including all catchments with < 25% impermeable surface, regardless of grade– All new and redevelopment projects

implement HM controls– Redevelopment projects of some workable

size (5000 ft2) decrease impervious surface by 25% or implement HM controls to reduce post-project flows as in WB Option 2 for entire redeveloped area

– Projects with up to 5000 ft2 impervious surface may use sizing charts for HM controls

– Larger projects use continuous simulation model

– Implement in 1 year

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C.3.f. ENGO Option 2 (cont’d)

• Projects discharging to transition zone, including all catchments with 25% - 70% impermeable surface, regardless of grade– New development projects of 1 acre or more

of impervious surface implement HM controls

– Redevelopment projects of 1 acre or more impervious surface decrease impervious surface by 25%, or implement HM controls to reduce post-project flows as in WB Option 2 for the entire redeveloped area

– Implement in 2 years

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C.3.f. ENGO Option 2 (cont’d)• Projects discharging to flat or built-

out zone, defined as including tidally influenced reaches and catchments with > 70% impervious surface– No HM requirements, unless evidence of

anadromous fish or special-status species or flooding

– If evidence of flooding or special-status species, Dischargers propose treatment in their HM plans

– If HMPs have not been approved by Water Board, projects follow rules for projects discharging to transition zone

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C.3.f. ENGO Option 2 (cont’d)

• Require one HM monitoring project per Program (except Vallejo), or cooperation on 3 region-wide projects

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C.3.f. Comments

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C.3.g. Alternative Compliance Based on Impracticability and Requiring

Compensatory Mitigation

• Current permits allow Dischargers to establish programs where projects may request alternative compliance with requirement to install sized onsite treatment BMPs (C.3.d.)

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C.3.g. BASMAA Option

• Maintain intent and approach of current permits and allow variation among local programs

• No finding of impracticability for granting equivalent offsite treatment alternative

• If an alternative compliance program is prescribed in the MRP, allow individual Dischargers to bring local compliance programs to Water Board for approval

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C.3.g. ENGO Option 1

• Simplify requirements and allow for variation among local programs while retaining a preference for onsite or nearby treatment

• No special treatment for brownfields, low- income housing, transit villages, etc.

• See flowchart

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Regulated Project Are onsite treatment, hydromod controls, or both impracticable?

Offsite Treatment• Maximize site design• Provide equivalent treatment and HM controls in same or nearby watershed • Capped at 2% of project costs

Sized Onsite Treatment and Hydromod Controls

Regional Project • Maximize site design• Provide equivalent treatment and HM controls• Same or nearby watershed

Regional Project• Maximize site design• Provide equivalent treatment and HM controls in same or nearby watershed • Capped at 2% of project costs

Funds for Equivalent Water Quality Benefit

• Maximize site design• Pay funds into projects that provide equivalent water quality benefit • Capped at 2% of project costs

Provision C.3.g. ENGO Option 1 Flowchart

yes

no

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C.3.g. ENGO Option 2

• If special treatment for brownfields, low-income housing, etc. retained:– Use EPA brownfield definition but project

must receive subsidy/benefits for redevelopment

– Low-income treatment applied proportionally to % that is actually low-income housing

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C.3.g. Water Board Option

• C.3.g. will be alternative compliance option (model program) for facilities that cannot install treatment BMPs onsite

• Dischargers will not have option to develop individual alternative compliance programs

• All alternative compliance programs approved by EO superseded by MRP

• See Attached Flowchart

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Regulated Project

Onsite Treatment

Impracticable?

Redevelopment and Brownfield; Low- or Moderate-Income or Senior Housing; or

Transit Village?

Install Sized Onsite Treatment

Minimize Impervious Surface Onsite Equivalent Offsite Treatment at

Regional Project

Maximize Site Design Treatment Controls

Equivalent Offsite Treatment Equivalent Water Quality Benefit

C.3.g. Water Board Option Flowchart

no

yes

yes

no

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C.3.g. Comments

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C.3.n. Reporting

C.3.a.– Report on changes Dischargers

made to ordinances, regulations, procedures to facilitate treatment and decreasing hydromodification (ENGO)

– Continue reporting as part of general effectiveness evaluation (BASMAA)

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C.3.n. Reporting (cont’d)

C.3.c.– Tabular form with specific column

headings (Water Board)– Deviations from Water Board

option (BASMAA):•No basis of impracticability required•No pre- and post- project flow duration curves required

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C.3.n. Reporting (cont’d)

C.3.c. (Water Board)– Reporting requirements for

new/replaced impervious surface from small projects

– Reporting requirements for source control, site design and any treatment measures installed for single-family homes

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C.3.n. Reporting (cont’d)

C.3.e.– Tabular form with specific column

headings (Water Board)– Summary form (BASMAA)– Deviations from Water Board

option (BASMAA):•No reporting of compliance status•Provision to re-evaluate reporting requirements in 3 years

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C.3.n. Reporting (cont’d)

General Requirements (Water Board)– For O&M Inspections:

•Overall compliance rates •Compliance rates for types of BMPs •Evaluation of compliance rates over time

– Discussion of effectiveness of program

– Proposed changes to improve program

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C.3.n. Reporting (cont’d)

General Requirements (BASMAA)– Evaluation of program

effectiveness using methods specified as guidance and not requirements

– Proposed changes to improve program

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C.3.n. Comments

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