It's legal, but see how whitewater kayaks and canoes are excepted:
(1)(a) The commission shall promulgate rules to prohibit the operation of vessels on any waters of the state and ordering the removal of vessels from any waters of the state when such operation constitutes or may constitute a hazard to human life or safety.
(b) For purposes of this subsection (1), “vessels” shall not include whitewater canoes and kayaks except in the case of:
(I) A state of disaster emergency pursuant to section 24-33.5-704
or 24-33.5-709, C.R.S
(II) Disaster relief efforts that are underway and that may include debris removal;
(III) An accident or other emergency that occurs in or immediately adjacent to the water body;
(IV) Rescue efforts for victims that are actively underway and such efforts would be hindered by additional waterway traffic; or
(V) Active construction or transportation projects authorized under state or federal law.
(2) Any parks and recreation officer or other peace officer as defined in section 33-10-102
has the authority to enforce this section under the rules promulgated by the commission.
(3) Any person who fails to obey an order issued under this section is guilty of a class 2 petty offense and, upon conviction, shall be punished by a fine of one hundred dollars.