RAFAEL L. CORTADA, the new president of the University of the District of Columbia, has been quick to assess the needs of that troubled institution. Mr. Cortada wants to create an open-admission, two-year community college within the university. UDC's five baccalaureate colleges would also be condensed and revised into three -- one for professional studies, one for science, math and technology and one for the arts.

Mr. Cortada wants, and deserves, quick approval of the plan from UDC's board of trustees to put the changes in place for the 1988-89 school year. "We cannot take a leisurely approach," Mr. Cortada says, adding that too many high school students no longer view UDC as a serious choice. He's right. UDC enrollment has plummeted from a high of 15,000 students in 1979 to only 9,600 this year.

More than 85 percent of UDC's freshmen are below the ninth-grade level in English and math, and many have flunked UDC's college-level courses. Those students would get the remedial help they need in the two-year college and could then, upon successful completion, transfer into UDC's four-year programs. Revising the four-year programs is equally important. There have been no significant curriculum changes in the past six years. Mr. Cortada mentioned word processing and training undergraduates to do legal research as new offerings that would attract more students. UDC could also become "more visible and more competitive" by offering advanced course work to the city's gifted high school students. Despite an expensive media campaign, UDC officials don't even have brochures to distribute when they meet prospective students.

The restructuring is important for another reason. At some point, UDC must try to bring its far-flung classrooms and libraries to more centralized locations. The current arrangement discourages poor students who can't afford to criss-cross the city each day. A study shows that UDC will pay out $71 million in rent over the next 10 years. Congress refused to fund the creation of UDC's Mount Vernon campus because of the enrollment decline. That decline won't stop without the restructuring Mr. Cortada suggests. That's reason enough to support his plans