Sadly, many people try to demythologize the Scriptures, watering down the miraculous events. The Church says in Denzinger (sourcebook for official Catholic teaching):
“If anyone shall have said that miracles are not possible, and hence that all accounts of them, even those contained in Sacred Scripture, are to be banished among the fables and myths; or that miracles can never be known with certitude…let him be anathema. (#1818).
Concerning how the Church determines the literal sense of Scripture, the Catechism says the following:
115 According to an ancient tradition, one can distinguish between two senses of Scripture: the literal and the spiritual, the latter being subdivided into the allegorical, moral and anagogical senses. The profound concordance of the four senses guarantees all its richness to the living reading of Scripture in the Church.
116 The literal sense is the meaning conveyed by the words of Scripture and discovered by exegesis, following the rules of sound interpretation: "All other senses of Sacred Scripture are based on the literal."83
117 The spiritual sense. Thanks to the unity of God’s plan, not only the text of Scripture but also the realities and events about which it speaks can be signs.
The allegorical sense. We can acquire a more profound understanding of events by recognizing their significance in Christ; thus the crossing of the Red Sea is a sign or type of Christ’s victory and also of Christian Baptism.84
The moral sense. The events reported in Scripture ought to lead us to act justly. As St. Paul says, they were written “for our instruction”.85
3.The anagogical sense (Greek: anagoge, “leading”). We can view realities and events in terms of their eternal significance, leading us toward our true homeland: thus the Church on earth is a sign of the heavenly Jerusalem.
119 “It is the task of exegetes to work, according to these rules, towards a better understanding and explanation of the meaning of Sacred Scripture in order that their research may help the Church to form a firmer judgement. For, of course, all that has been said about the manner of interpreting Scripture is ultimately subject to the judgement of the Church which exercises the divinely conferred commission and ministry of watching over and interpreting the Word of God.”
See *Catechism Catholic Church * 289 and 390
On Noah’s Ark:
*Catechism of the Catholic Church * no. 1219:
“The Church has seen in Noah’s ark a prefiguring of salvation by Baptism, for by it “a few, that is, eight persons, were saved through water”: The waters of the great flood
you made a sign of the waters of Baptism, that make an end of sin and a new beginning of goodness.
"The covenant with Noah after the flood gives expression to the principle of the divine economy toward the “nations”, in other words, towards men grouped “in their lands, each with [its] own language, by their families, in their nations”.
*Commentary on Genesis * by Father William Most:
*Free From All Error * By Father William Most
*Basic Scripture * by Father William Most
(excellent source for information on the genre approach to defending the inerrancy of Scripture)