While it might not reach biblical proportions, a huge number of shares of Google (NASDAQ:GOOG) stock will be flooding the market, possibly doubling the amount outstanding. Last week, the lockup period expired for more than 39 million shares of insider-owned stock -- and the insiders have been lining up to dump their shares back on the market.

John Doerr, acting on behalf of venture capital firm Kleiner Perkins, filed to sell almost 6 million shares, which are worth $997 million. Google itself had previously adopted the SEC Rule 10b5-1 trading plan in September that will allow founders Larry Page and Sergey Brin and CEO Eric Schmidt to sell their shares as part of an 18-month diversification plan.

The SEC adopted Rule10b5-1 to protect executives from charges of insider trading by allowing them to legally buy or sell shares in their company even if they are aware of material non-public information so long as the trade was specifically laid out in a plan before the executive became aware of the information.

Many companies prohibit executives from trading stock two to four weeks before a quarter ends and several days after the earnings have been released. That prohibits officers from trading for as many as 24 weeks a year. And if a company is involved in mergers, management changes, or other events that would affect the share price, there might be precious few chances to buy or sell shares. The Rule 10b5-1 trading plan lets executives diversify their holdings when they otherwise would have had a difficult time finding a window of opportunity to do so.

Page and Brin intend to sell 7.2 million shares each over the next 18 months, while Schmidt has filed to sell more than 2 million. Collectively, the three own more than 90 million shares, representing 33% of the company's stock and almost 46% of the voting power. After the sale, they'll still own nearly 74 million shares and still control more than 40% of the voting power.

Google's stock has been on a tear since its IPO in August. The stock was offered at $85 a share and reached as high as $201 at the start of this month, before easing back 23% to $164 as investors eyed the lockup expiration and wondered whether it was overpriced at current valuations. At Friday's close, it had a $46 billion market cap, putting it in the realm of Yahoo! (NASDAQ:YHOO) at $49 billion and Disney (NYSE:DIS) at $53 billion, and not far from the likes of eBay (NASDAQ:EBAY) at $71 billion, but ahead of Amazon (NASDAQ:AMZN) at $16 billion. Even after pulling back, Google retains a lofty valuation.

Some analysts still see enough demand from the public to offset the dilution that will occur from the flood. And some folks are willing to buy this stock at any price. This Fool, however, while admiring the brand and the breadth of services it offers, will be wearing hip waders as the shares flood the market.

For related Foolish anlysis of Google, see:

Fool contributor Rich Duprey believes hip waders are incredibly more fashionable than Uggs. He does not own any of the stocks mentioned in this article.