Federal legislators urged the Sierra Club not to delay the Tahoe Regional Planning Agency’s Regional Plan Update prior to the environmental group’s challenge to the wide-ranging plan this week.The existence of the TRPA, as well as millions of dollars in federal funding, could be jeopardized by delays in implementation of the RPU, according to a Feb. 1 letter to the Sierra Club from U.S. Sens. Harry Reid and Dianne Feinstein.The Sierra Club and Friends of the West Shore filed a lawsuit to stop implementation of the TRPA’s RPU in federal court on Monday. The TRPA passed the plan regulating land use in the Lake Tahoe Basin in December. The environmental groups question the ability of the new regulations to achieve the agency’s environmental goals and criticizes an effort by the TRPA to give more control to local governments.Feinstein and Reid encouraged the Sierra Club to “refrain from any actions that might result in the dissolution of the bi-state compact or setback our efforts to pass legislation to help restore lake clarity.”“The adoption of the plan is the result of nearly a decade of work by TRPA, local government, residents, business owners and environmental groups and takes into account more than 5,000 public comments,” according to the letter. “The plan reflects policy compromises of this diverse group of stakeholders with the overarching goal of restoring Lake Tahoe’s world-famous clarity while at the same time supporting desperately needed revitalization.”Any delays to the implementation of the Regional Plan Update could jeopardize the Bi-State Compact that established the TRPA, the senators wrote.“This compact, which was first ratified by Congress in 1969, is vital to the preservation of Lake Tahoe,” according to the letter. “If either state were to withdraw from the compact, as proposed under existing Nevada state law, the decades-long investment we have collectively made in Lake Tahoe’s restoration would be undermined.”The senators said they would welcome Sierra Club input on a reauthorization of the Lake Tahoe Restoration Act, which previously enabled more than $1 billion in environmental improvements at the lake. “However, we urge you not to take any steps which might foster the misperception that California and Nevada disagree on Lake Tahoe restoration plans, undermining our bipartisan legislation and jeopardizing hundreds of millions of dollars in federal support for restoration work over the next decade.”Representatives from Reid’s and Feinstein’s offices did not immediately return a request for comment late Thursday evening.Bruce Hamilton, the deputy executive director of the Sierra Club, said the environmental group hoped to extend the deadline for a lawsuit in order to negotiate further with the TRPA.“We agreed with the Senators that it was far better to work out a better plan than to litigate, so we made a good faith effort to get TRPA to agree to extend the deadline to sue in order to facilitate negotiations in the hope of avoiding a suit — but they refused,” Hamilton said in an email. “That refusal left us with the choice of either letting a terrible plan that won’t protect the lake go forward unchallenged, or to proceed with the litigation. For the sake of Lake Tahoe, a national treasure, and all Americans who enjoy the lake’s pristine clarity, we chose the latter.”An initial hearing date has not been set in the lawsuit challenging the RPU. The Sierra Club is seeking an injunction to stop implementation of the plan, but TRPA officials have said they will continue moving forward with the plan until a judge says otherwise. The TRPA has 21 days to answer the complaint after being served with the lawsuit, according to online court documents.