I think that “lac aveugle” just means “blind lake”. It's a technical term in geography, and several lakes that are blind are called “Blind Lake”. There are places called (the local translation of) Blind Lake in France, in the US, in Austria (Blindsee), in Pakistan (Sheosar Lake), … I don't think they're all blind, for example the one in Pakistan doesn't seem to be.
A that a blind lake is one that doesn't have any runoff above ground. It is blind in the sense of having no exit (see e.g. Oxford British & World English, def. 3.2), which gives the example sentence
Such blind pools loose water by evaporation, or if below the water table remain as permanent bodies.
The Québec Grand Dictionnaire terminologique gives the following definition for aveugle in geography:
Qualifie la terminaison d'un chenal ou d'une vallée s'achevant par une contre-pente : - dans les régions karstiques, la vallée aveugle se termine par une perte de rivière; - sur les estrans, les chenaux de marée sont fréquemment aveugles.
My translation: “characterizes a channel or valley which ends in a reverse slope: in karstic areas, the blind valley ends with the loss of the river; on the foreshore, tide channels are often blind”.
The Trésor de la langue française does not give examples from geography, but cites “cavité aveugle” (“blind cavity”) in medecine (in both languages, that's a part of an organ that can contain fluid and that terminates in a dead end). In both French and English, this term is also used in plumbing (the Oxford dictionary gives the example “blind pipe”). It may have derived from uses in architecture, where “aveugle” (or “blind” in English) refers to an area with no openings that let the light in. This would bridge the meanings “unable to see” and “no opening”.