Here is the  Summary Report (PDF) recently issued by the Regional Water Quality Control Board detailing what is being proposed with the MS4 permit update and what has changed in the recently released revised draft of the new regional stormwater permit. 

Below find an excerpt from attachment F of the draft permit which explains a bit of stormwater history, and the current draft differs from previous stromwater permits.

V. REGIONAL MS4 PERMIT APPROACH

The Fifth Term Permit, or Regional MS4 Permit, shifts the focus of the permit

requirements from a minimum level of actions to be implemented by the Copermittees

to identifying outcomes to be achieved by those actions. Order No. R9-2013-0001

represents an important paradigm shift in the approach for MS4 permits within the San

Diego Region.

Historical Permitting Approach

The First and Second Term Permits were very broad and provided little specificity

about what was required to be developed and implemented by the Copermittees. The

Third Term Permits began to become more specific about the minimum level of

implementation required by the Copermittees. The Fourth Term Permits, or current

permits, subsequently increased in specificity. The MS4 permits have progressively

become more detailed and focused on specifying the minimum level of actions

expected to be implemented by the Copermittees. As detailed and specific as the

MS4 permits have become, however, they include very little detail about what the

desired outcomes of the required actions are expected to achieve. Compliance with

the permit requirements has essentially been tracking numbers of actions and

reporting, not tracking progress or actual improvements in the quality of receiving

waters or discharges from the MS4s. The result has been an increase in actions being

implemented by the Copermittees with little or no ability or expectations to determine

whether or not improvements in water quality are being achieved.

The Fourth Term Permits result in significant resource expenditure by the

Copermittees to report permit compliance information to the San Diego Water Board in

the form of annual jurisdictional runoff management program, watershed program, and

monitoring program reports. The San Diego Water Board must then expend much of

its limited resources on reviewing more than 50 voluminous reports submitted annually

by the Copermittees. The information currently reported by the Copermittees is of

limited value when trying to measure progress toward achieving improvements in the

quality of receiving waters or discharges from the MS4s. Oversight of the MS4 permits

is further complicated by the inconsistencies among the requirements issued to the

Orange County, San Diego County, and Riverside County Copermittees under three

separate MS4 permits.

Under the Fourth Term Permits, the Copermittees must expend a significant portion of

their limited resources collecting data of limited value, and putting together reports to

submit that information to the San Diego Water Board. Likewise, the San Diego Water

Board must expend most of its limited resources reviewing reports, and developing

permits instead of working directly with the Copermittees to identify solutions to

problems causing impacts to water quality. This is an unsustainable course that will

continue to demand more resources from the Copermittees and the San Diego Water

Board, and would continue to result in unknown water quality benefits.

New Permitting Approach

The goal of the Regional MS4 Permit is twofold: 1) bring a consistent set of MS4

permit requirements to all of the Copermittees within the San Diego Region; and, 2)

provide a MS4 permit with requirements that will allow the Copermittees to focus their

efforts and resources on achieving goals and desired outcomes toward the

improvement of water quality rather than completing specific actions.

The overall approach included in the Regional MS4 Permit with respect to the

jurisdictional runoff management programs will not differ significantly from the current

permits. The general requirements for the jurisdictional runoff management program

components and compliance with those requirements will remain and be applied

consistently throughout the San Diego Region under the Regional MS4 Permit.

The most significant difference in the new permitting approach is the specific manner

of implementation for those jurisdictional runoff management programs.

Implementation will be based on decisions made by the Copermittees in accordance

with what they have identified as their highest priority water quality conditions. In other

words, the Copermittees will have significant control in how to implement the

jurisdictional runoff management programs to best utilize their available resources in

addressing a specific set of priorities effectively, instead of trying to address all the

water quality priorities ineffectively.

The Copermittees are given the responsibility of identifying their highest priority water

quality conditions that they intend to address. The Copermittees will develop goals

that can be used to measure and demonstrate progress or improvements toward

addressing those priorities. In addition to the goals, the Copermittees will provide a

schedule for achieving the goals for those highest priorities. The measurement of

progress toward achieving the goals for those highest priorities requires a better

defined and more focused program of monitoring and assessment than under the

Fourth Term Permits.

The monitoring and assessment program must be designed to inform the

Copermittees of their progress, and the need for modifications in their jurisdictional

runoff management programs and schedules to achieve their goals to improve water

quality. The monitoring and assessment program requirements will have a more

central role in the Regional MS4 Permit than in earlier permits. The monitoring and

assessment requirements must also be designed to enable the Copermittees to focus

and direct their efforts in implementing their jurisdictional runoff management

programs toward their stated desired outcomes to improve the quality of receiving

waters and/or discharges from the MS4s.

By providing a MS4 permit that allows the Copermittees to make more decisions about

how to utilize and focus their resources, along with a better defined monitoring and

assessment program to inform their water quality management decisions, the

Copermittees will have the opportunity to:

1) Plan strategically. The Copermittees must have the ability to identify their available

resources and develop and implement long term plans that can organize, collect,

and use those resources in the most strategically advantageous and efficient

manner possible. This ability to develop long term plans will allow the Copermittees

to focus and utilize their resources in a more concerted way over the short term and

long term to address specific water quality priorities through stated desired

outcomes.

2) Manage adaptively. The Copermittees must be given the ability to modify their

plans as additional information and data are collected from the monitoring and

assessment programs. The Copermittees’ plans may require modifications to the

programs, priorities, goals, strategies, and/or schedules in order for the

Copermittees to achieve a stated desired outcome.

3) Identify synergies. The Copermittees must be given more flexibility to identify

efficiencies within and among their jurisdictional runoff management programs as

the strategies are developed and implemented to increase the Copermittees’

collective effectiveness. The Copermittees must also be able to identify and utilize

resources available from other agencies and entities to further augment and

enhance their jurisdictional runoff management programs and/or to collectively work

with those other agencies and entities toward achieving a stated desired outcome.

The Regional MS4 Permit requirements will provide the Copermittees the flexibility and

responsibility to decide what actions will be necessary to achieve an outcome that is

tailored and designed by the Copermittees to improve specific prioritized water quality

conditions. The San Diego Water Board expects the approach of the Regional MS4

Permit to give the Copermittees a greater sense of ownership for restoring the quality

of receiving waters in the San Diego Region by becoming an integral part of the

decision making process in identifying water quality conditions to be addressed, as

well as determining the best use of their resources.

(Link to actual document)