The purpose of this page is to inform interested parties about the the overall statewide diversion rate calculation for 1999. This information was first released in a memorandum from Ralph E. Chandler, Executive Director of the California Integrated Waste Management Board to Winston H. Hickox, Secretary of the California Environmental Protection Agency, on February 2, 2000.

1999 Diversion Rate: 37 Percent

California continues to make excellent progress toward the ambitious 50 percent diversion goal. In 1999 the statewide diversion rate reached 37 percent, a 12 percent increase over the 1998 statewide diversion rate of 33 percent. This increase in diversion is the largest single year measured increase since 1992. Please see the attached, "Estimated California Solid Waste Tonnages and Diversion Rates," a table representing ten years of diversion program performance.

Each year the Diversion, Planning, and Local Assistance Division (DPLA) reports on statewide progress toward the diversion goals of the Integrated Waste Management Act of 1989. Prior to 1997 the statewide diversion rate estimate was typically available in late spring. This was due to the Disposal Reporting System schedule and availability of information provided by other state agencies. Because concerns were raised about this delayed reporting, starting in 1997 staff made efforts to ensure earlier, more uniform diversion rate estimates. The statewide diversion rate estimates are now based on the Federal Fiscal Year (October 1998 through September 1999) to provide an estimated diversion rate as close to the beginning of each year as possible.

Calculation Methodology

The purpose of AB 939 was to conserve resources and extend landfill capacity, not to penalize jurisdictions for increases in population or economic growth. Thus, having more residents or more businesses will not automatically cause jurisdictions to fail to meet the diversion goals. The impacts of demographic changes on the waste stream must be considered when calculating diversion rates. By incorporating these demographic factors, the Board-approved Adjustment Method allows valid comparisons between years regardless of the changes in population and economics.

Because the information needed for diversion rate estimation and disposal fee revenue estimation is very similar, DPLA and the Administration & Finance Division’s General Financial Services Branch worked closely to locate data and verify results. Use of the Federal Fiscal Year results in differences between the disposal amounts shown in the attached graph, "Estimated California Solid Waste Tonnages and Diversion Rates from 1990 through 1999", and disposal tonnage calculated for revenue purposes. Other methods of disposal (such as transformation and export) are included in the diversion rate estimation but are not included in revenue calculations based on landfill disposal, so the disposal amounts are different.

The first step in performing the calculation was to determine the 1999 statewide waste generation tonnage. Generation is the total amount of waste disposed and diverted. To arrive at this number, we started with the statewide base year (1990) generation tonnage. We applied the Board Approved Adjustment Method, which uses changes in population and economics, to adjust 1990 generation forward to 1999. Using the Adjustment Method, 1999 estimated statewide generation was 59.7 million tons.

The next step was to determine statewide disposal. Disposal is the total amount of waste that is landfilled, exported out of the state, and transformed. The Disposal Reporting System (DRS) tracks the amount of waste disposed by each jurisdiction in the state. In 1999 total disposal was 37.5 million tons. By dividing this number by statewide generation, we arrived at a disposal rate of 63 percent.

To determine the 1999 diversion rate we subtracted disposal (63 percent) from generation (100 percent) to get 37 percent. Approximately 22.2 million tons were diverted from landfills in 1999, an increase of about 3.7 million tons over 1998. While total generation increased by 3.8 million tons, disposal only increased by about 100,000 tons (less than 1 percent). Virtually all of the increase in generation tonnage from 1998 to 1999 was diverted.

Return to current year diversion rates memo to view previous years' statewide diversion rates.

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