Before a drop of water can move to the coast, IID must finish an environmental impact report and environmental impact statement addressing the effect the transfer would have on the environment.
The habitat conservation plan would be included as part of the environmental impact reports.
IID General Manager Jesse Silva said he thinks it could take six months to finish all the environmental reports, adding the timeline calls for IID to start transferring water in 2002.
He said he is hopeful the district can stick to the timeline. However, like Horne, Silva said he is concerned the cost of mitigation activities could reach the hundreds of millions of dollars, based on the talks with federal wildlife officials.
Silva said if that did occur, the district would have to consider other options.
Horne said the federal and state governments would have to provide money to make the transfer happen if the costs for mitigation reached a level the district could not afford.
Horne said the largest mitigation cost would relate to the Salton Sea, which could be affected by the effort to conserve water for the transfer.
Conservation efforts could reduce the flow of water into the sea, which could reduce the sea's level. If that were to occur the salt concentration of the sea, already high, would rise.
IID officials said talks on the habitat conservation plan would not only affect the water transfer but all other water agreements related to settling the question of how much water the state is entitled to from the Colorado River.
One such agreement is the quantification settlement, which creates a 75-year period of "peace" between IID, the Coachella Valley Water Authority and the Metropolitan Water District of Southern California.
The settlement calls for IID to transfer 100,000 acre-feet per year to be divided between the two water agencies. In return CVWA and MWD would not challenge IID's right to sell water to San Diego.
Another key agreement being developed, the California Colorado River Use Plan, is dependent upon the water transfer to San Diego coming to fruition.
The river use plan would cut California's dependence on the Colorado to 4.4 million acre-feet per year. The transfer to San Diego is a part of that plan.
Horne said if the transfer to San Diego does not occur, "it would be like the proverbial house of cards" in that all the water agreements would be in jeopardy.
IID officials have said the transfer must happen to protect the interests of the district.
They have said without the transfer they are concerned the state or federal government would demand water from the Imperial Valley to meet the needs of coastal areas.
Staff Writer Darren Simon can be reached at 337-4082.