SOUTH LAKE TAHOE, Calif. — Alternative energy credits are designed to reduce the world's dependence on fossil fuel.

Carbon credits are used to reduce the amount greenhouse gases entering the atmosphere.

And “Lake Clarity Credits” could soon be used to try and reverse Lake Tahoe's historic clarity decline.

The Lahontan Regional Water Quality Control Board, the Nevada Division of Environmental Protection and the Tahoe Regional Planning Agency are developing a “Lake Clarity Crediting Program” to track implementation of the Lake Tahoe Total Maximum Daily Load, known as the TMDL.

Lahontan and NDEP have developed the TMDL since 2001 to determine the amount of nitrogen, phosphorus and fine sediment that needs to be prevented from reaching Lake Tahoe in order to restore the lake to approximately 100 feet of clarity. The three pollutants have been blamed for reducing the lake's average clarity from 102.4 feet in 1968 to 69.6 feet in 2008.

Seeing 100 feet

To achieve approximately 100 feet of clarity, fine sediment particles entering the lake need to be reduced by 65 percent, phosphorus entering the lake needs to be reduced by 35 percent and nitrogen needs to be reduced by 10 percent, according to a June draft of the TMDL. The reductions could take 60 years or more, according to the document.

In the meantime, Lake Tahoe Basin water quality regulators have set the first milestone for achieving 100 feet of clarity at 24 meters — about 79 feet — by 2028. Meeting the milestone will require a 32 percent reduction of fine sediment particles, a 14 percent reduction in phosphorus, and a 4 percent reduction in nitrogen entering the lake, according to the June draft.

The crediting program is designed as an accounting system to quantify the progress each jurisdiction at the lake makes toward reaching those reductions, according to a handbook about the program sent to local stakeholders in September.

Counting the particles

Under the program, the city of South Lake Tahoe, Caltrans, the Nevada Department of Transportation and El Dorado, Placer, Washoe and Douglas counties will be given requirements for the reduction of pollutants over five-year periods.

Each jurisdiction would then be awarded credits annually based on their effectiveness in accomplishing the requirements. Each credit would represent 10 quadrillion fine sediment particles — about 200 pounds worth — that a jurisdiction prevented from reaching the lake.

The credit system would be used to determine if each jurisdiction is in compliance with National Pollutant Discharge Elimination System permits and Memoranda of Agreements issued by the water board and NDEP, according to the handbook.

Jurisdictions that don't meet requirements could face monetary penalties, said Bob Larsen, an environmental scientist with the Lahontan water board.

Whether jurisdictions are showing effort to comply with the crediting program will be taken into consideration when the board considers consequences for not meeting the program's requirements, Larsen said.

The water board has been good about reaching out to local jurisdictions to help them implement the important and “very complex” program, said Norma Santiago, El Dorado County Supervisor and TRPA Board member.

“It is challenging, but it seems like Lahontan is willing to work with us,” Santiago said.

What about clarity “debits”?

Basin conservation groups have sounded off about the program.

One significant problem is that the program does not contain a “debit” component that could be used to dock local jurisdictions when their activities negatively affects water quality, said Carl Young, program manager with the League to Save Lake Tahoe.

The crediting program is wrong to assume every project can be mitigated to a negligible effect, let project developers do their own monitoring, and not take into account undeveloped land's effect on water quality, Young said.

Self-reporting is like letting “the wolves guard the hen house,” Young said.

“The crediting system needs more work to both safeguard water quality and make sure the investments that are made are worthwhile and not wasteful,” Young said.

Existing water quality regulations already hold jurisdictions that negatively effect water quality accountable and the credit program will target fine sediment runoff from urban areas first because of the prominent role the areas play in Lake Tahoe's clarity loss, Larsen said.

Fine sediment accounts for about two thirds of lake clarity loss and 70 percent of the fine sediment particles reaching the lake are generated from urban stormwater runoff, according to the handbook.

Updates to the program are expected to occur in summer and fall, with incorporation TRPA, water board and NDEP policies permits and code as soon as the fall of 2010.