BIRKENHEAD got bogged down in the dreadful conditions as they just missed out in this National Three North clash.
Relentless rain led to an error-strewn first period and it was little better later.
Rochdale capitalised on Park errors for two first-half penalties via Steve Collins.
The visitors closed to within a point with a corner try by Dave Hall following steady pressure after an hour but Rochdale held on in a dour struggle best forgotten.
Andy Trotter tried hard on the wing for Park. Ryan Stead and Jon Feldman did their best after going on as replacements in the second period but little went right for Park with too many players having an off day.
