A clout-heavy Chicago law firm is helping the Trump Tower defend itself against charges that it’s breaking environmental laws and harming the Chicago River.

The Katten Muchin Rosenman LLP firm — which employs former Chicago Mayor Richard M. Daley — is representing the Trump Tower in the case filed last month by Illinois Attorney General Lisa Madigan, according to court records.

Madigan sued the Trump Tower on Aug. 13. She alleges that the 98-story tower in downtown Chicago is releasing 20 million gallons of water into the river without permits, potentially endangering fish and other aquatic life.

Nine days after Madigan sued, lawyers for Katten Muchin Rosenman entered their appearance for the Trump Tower in Cook County Circuit Court, records show.

Daley began at the firm when he left office in 2011 after a record-breaking 22-year tenure as mayor, joining close friend Terry Newman.

According to the firm’s website, Daley is “of counsel” at Katten Muchin Rosenman.

While Daley was mayor, the firm represented the city in the hotly criticized, 75-year privatization of Chicago’s parking meter system.

Daley’s longtime spokeswoman at City Hall, Jacquelyn Heard, also joined the firm and continues to be its communications chief. Heard declined to comment Friday.

A spokeswoman for the Trump Organization did not return calls. The Republican president’s company has said the suit filed by Madigan — who’s a Democrat — is “motivated by politics.”

Ald. Ameya Pawar (47th Ward) says the Trump Tower has the right to legal help in the case — but he doesn’t think Katten Muchin Rosenman should be providing it.

Pawar notes that, as president, Trump has tried to cut federal funding for the city in retaliation for Chicago’s “sanctuary city” policies.

“They’ve liked to position themselves as civic leaders, and I would ask them does it really make sense to represent the president, who is a racist, a bigot, and who’s actively working to penalize Chicago for being a welcoming city to immigrants,” Pawar said of Katten Muchin Rosenman.

Pawar similarly has criticized his City Council colleague Ed Burke, who represented the Trump Tower in property tax appeals cases for years.

That issue was raised repeatedly earlier this year in the primary defeat of Burke’s brother, state Rep. Dan Burke (D-Chicago).

Ed Burke’s small firm saved the Trump Tower $14 million in property taxes over 12 years by arguing for it before Cook County officials, the Chicago Sun-Times reported.

But the alderman — who’s up for re-election in February — stopped representing the Trump Tower in May, citing “irreconcilable differences.”

Dan Mihalopoulos is an investigative reporter for WBEZ. Follow him at @dmihalopoulos.